Medical implant

Abstract

The present disclosure provides a medical implant (3500), for example a neurostimulator or diagnostic implant, comprising: a housing assembly (3502) comprising: a tubular housing (3504); an electronics assembly received at least partially within the tubular housing; and a feedthrough comprising one or more feedthrough connectors connected to the electronics assembly; an electrode lead (3508) comprising one or more lead wires; and a lead connector configured to attach the electrode lead to the housing assembly, having one or more conducting paths that electrically connect the lead wires to the one or more feedthrough connectors, wherein the lead connector comprises a flexible substrate (3530) and the one or more conducting paths are provided in or on the flexible substrate, the flexible substrate being bendable to vary an angle between the electrode lead and the housing assembly.

Description

MEDICAL IMPLANT

[0001] This invention relates to a medical implant, such as a neurostimulator implant or a sensing or diagnostic implant. The medical implant is implantable into a patient’s tissue.BACKGROUND

[0002] It is known to provide a medical implant comprising a housing and an electrode. The medical implant, in particular the electrode, may be operated to sense one or more parameters of the patient, for example for health monitoring or diagnostics, and / or to provide neural stimulation. Typically, a power antenna, microcontroller, and communication antenna are disposed in the housing for receiving power from an external source. The external source is typically a wearable device and receives / transmits signals relating to the electrode. Examples of such medical implants are neurostimulator implants that may be used to treat specific conditions, such as chronic pain. Other examples may be health monitoring implants that detect one or more parameters of the patient, such as heart rate, blood pressure and the like. These medical implants have been designed to be small and energy efficient, and can be implanted in a minimally invasive procedure.SUMMARY

[0003] According to the invention there is provided a medical implant and a method of assembling a medical implant according to the appended claims.

[0004] According to the invention, there is provided a medical implant, for example a neurostimulator or diagnostic implant. The medical implant comprises a tubular housing formed of an electrically insulative material. The tubular housing has an electrode on an outer surface of the tubular housing and an electrode track extending from the electrode. The medical implant further comprises an electronics assembly housed within the tubular housing. The medical implant further comprises an end cap arranged to hermetically seal a first end of the tubular housing, the end cap comprising a conductive track arranged to connect with the electrode track and with the electronics assembly within the tubular housing to electrically connect the electrode and the electronics assembly.

[0005] Advantageously, the end cap thereby provides a hermetic seal at the first end of the tubular housing and provides a feedthrough for electrical connection of the electrode on the outside of the tubular housing to the electronics assembly on the inside of the tubular housing.

[0006] In examples, the end cap extends into the first end of the tubular housing. The end cap may be an end plug.

[0007] In examples, the electrode is spaced from the first end of the tubular housing, and wherein the electrode track extends along the outer surface of the tubular housing from the electrode towards the first end of the tubular housing.

[0008] In examples, the electrode track extends through the thickness of the tubular housing proximal to the first end of the tubular housing to define a contact on an inner surface of the tubular housing, and wherein the conductive track of the end cap extends to a side of the end cap for connection with the contact of the electrode track. For example, the conductive track may extend to a circumferential side of the end cap.

[0009] In examples, the electronics assembly is in contact with the inner surface of the end cap to form an electrical connection with the electrode track.

[0010] In examples, the conductive track of the end cap comprises a connecting pin connected to the electronics assembly. In examples, the connecting pin protrudes from an outer surface of the end cap, and wherein the electrode track comprises an arm connected to the connecting pin at the outer surface of the end cap.

[0011] In examples, the electronics assembly, in particular a printed circuit board, PCB, of the electronics assembly, is in contact with the inner surface of the end cap to form an electrical connection with the electrode track. The electronics assembly, in particular the PCB, may include one or more connection pads that contact the conductive track on the end cap. The conductive track may include a connecting pin arranged to connect the conductive track to the electronics assembly. The connecting pin may protrude from the inner surface of the end cap for connection to the electronics assembly, in particular the PCB.

[0012] In examples, the medical implant further comprises a coupling extending between the inner surface of the end cap and the electronics assembly to electrically connect the electronics assembly to the electrode track. The coupling may connect to the electronics assembly, in particular the PCB, via a friction fit and / or one or more contact pads. The coupling may include one or more spring contacts to contact the conductive track on the end cap.

[0013] In examples, the inner surface of the end cap comprises a socket. The conductive track terminates in the socket and defines a contact within the socket. In examples, the electronics assembly comprises a printed circuit board, PCB, and a connector, the connector having a first end joined to the PCB and a second end comprising a plug in engagement with the socket in theend cap. In examples, the connector comprises a conductive track extending from the plug, where it is in contact with the contact in the socket, to the first end, where it is connected with the PCB. In examples, the first end of the connector comprises a U-shaped opening to receive the PCB. The U-shaped opening may comprise one or more contacts for forming an electrical connection with the PCB. In examples, the connector comprises a rod between the first end and the second end. In examples, a tubular-shaped capacitor of the electronics assembly is housed about the rod.

[0014] In examples, the electronics assembly, in particular the PCB, is supported at an end opposite to the connector so that the electronics assembly is sandwiched within the tubular housing. The electronics assembly, in particular the PCB, may be supported by a feedthrough at the end opposite to the connector.

[0015] In examples, the electrode is formed in a recess or groove in the outer surface of the tubular housing. In examples, the electrode is a ring electrode extend circumferentially about the tubular housing. In examples, the tubular housing comprises a plurality of electrodes and a plurality of electrode tracks. In examples, the end cap comprises a plurality of conductive tracks, each conductive track being connected with one of the plurality of electrodes. In examples, two of the plurality of electrodes form an interdigitated electrode pair.

[0016] In examples, the tubular housing comprises a ceramic material, for example zirconia.

[0017] In examples, the end cap comprises a ceramic material, for example zirconia. In other examples, the end cap comprises a metallic material, for example platinum-iridium. In examples, the conductive track extends through the end cap, and the end cap further comprises an insulating sleeve arranged to insulate the conductive track from the metallic material of the end cap. In examples, the end cap is electrically connected to the electronics assembly such that the end cap forms an electrode. The electrode may be operable for sensing and / or stimulating.

[0018] In examples, the medical implant further comprises a weld ring attaching the end cap to the tubular housing. In examples, the weld ring is electrically connected to the electronics assembly and forms an electrode.

[0019] In examples, the or each electrode is operable for one or more of: sensing a parameter of the patient when the medical implant is implanted, for example a physiological parameter, a vital sign or a bioimpedance, providing stimulation to a target nerve or target location of the patient when the medical implant is implanted, and / or connecting to an external power source for powering the medical implant before and / or during implantation of the medical implant.

[0020] In examples, electrodes formed on the tubular housing and / or on the electrode lead may be configured as sensing electrodes. Two of more of the electrodes on the tubular housing and / or on the electrode lead may comprise different materials, in particular different metals such as gold and platinum. In examples, at least two of the electrodes on the tubular housing and / or on the electrode lead are formed of different materials (e.g., different metals) and used for differential bioimpedance sensing. For example, bioimpedance measurements taken by at least two of the electrodes may be used to determine a biochemical parameter at the implantation site, such as the presence and / or concentration of a chemical, for example proteins, alcohol, and glucose. Bioimpedance measurement data may be transmitted to the external device and may be combined with other data to form a biochemical sensing system for biochemical analysis.

[0021] In examples, the medical implant further comprises an electrode lead extending from a second end of the tubular housing opposite to the first end, the electrode lead comprising one or more electrodes.

[0022] In examples, the one or more electrodes are operable for one or more of: sensing a parameter of the patient when the medical implant is implanted, for example a physiological parameter, a vital sign, or a bioimpedance, detecting a neural signal of a patient's nerve when the medical implant is implanted, providing neural or non-neural stimulation to the patient when the medical implant is implanted.

[0023] In examples, the medical implant further comprises an electrode lead extending from a second end of the tubular housing opposite to the first end. The electrode lead comprises one or more electrodes and one or more corresponding electrode wires. The tubular housing comprises a feedthrough arranged to seal the second end of the tubular housing and provide an electrical connection between the or each electrode wire and the electronics assembly within the tubular housing. The feedthrough may be an end cap.

[0024] In examples, the medical implant further comprises a weld ring joined to the second end of the tubular housing. The feedthrough may be disposed within the weld ring. In examples, the weld ring is a first weld ring, and the medical implant further comprises a second weld ring joined to the end of the tubular housing, and wherein the first weld ring and the second weld ring are welded together. In examples, the or each weld ring is electrically connected to the electronics assembly such that the or each weld ring forms an electrode. The electrode may be operable for sensing and / or stimulation.

[0025] In examples, the electrode lead has a length of up to about 100 millimetres, for example up to about 50 millimetres, for example up to about 30 millimetres, for example up to about 25 millimetres, for example up to about 20 millimetres, for example about 20 millimetres.

[0026] In examples, the tubular housing has an outer diameter of less than about 5 millimetres, for example between about 1 millimetre and about 5 millimetres, for example between about 1 millimetre and about 3 millimetres, for example about 3 millimetres.

[0027] In examples, the tubular housing has a length of up to about 30 millimetres, for example up to about 25 millimetres, for example up to about 20 millimetres, for example about 20 millimetres.

[0028] In examples, the medical implant is a battery-less implant.

[0029] In examples, the medical implant may further comprise a piezoelectric or triboelectric sensor element. The piezoelectric or triboelectric sensor element may be formed on the tubular housing, for example on the outer surface of the tubular housing, for example in a ring extending about the tubular housing. In other examples, the piezoelectric or triboelectric sensor element may be formed on the end cap, feedthrough, cover or other part of the medical implant. The piezoelectric or triboelectric sensor element may be connected to the electronics assembly within the tubular housing through the end cap in the same manner as the electrode. The piezoelectric or triboelectric sensor element may be used for sensing one or more parameters, for example physiological parameters such as such as body temperature, blood pressure, or heart rate. In some examples, the medical implant comprises a piezoelectric or triboelectric insert on the tubular housing, end cap or other location. The piezoelectric or triboelectric insert may be used for power harvesting, for example to generate electrical power from movement and / or forces applied to the piezoelectric or triboelectric insert at the implantation site.

[0030] According to a further aspect of the present invention, there is provided a medical implant, for example a neurostimulator or diagnostic implant, comprising: a tubular housing, an electronics assembly housed within the tubular housing, an electrode lead extending from an end of the tubular housing, the electrode lead comprising one or more electrodes and one or more corresponding electrode wires, and a feedthrough arranged to seal the end of the tubular housing and having one or more connectors extending through the feedthrough to provide an electrical connection between the or each electrode wire and the electronics assembly within the tubular housing.

[0031] In examples, the feedthrough comprises a weld ring joined to the end of the tubular housing, and a body disposed within the weld ring. The one or more connectors extend through the body to provide an electrical connection between the or each electrode wire and the electronics assembly.

[0032] In examples, the body is a ceramic body. In other examples, the body is a metallic body, and the one or more connectors are insulated from the metallic body.

[0033] In examples, the weld ring is a first weld ring, and the medical implant further comprises a second weld ring joined to the end of the tubular housing, and wherein the first weld ring and the second weld ring are welded together. In examples, the tubular housing is ceramic and the second weld ring is brazed to the ceramic tubular housing.

[0034] In examples, the medical implant further comprises a lead connector joined to the electrode lead and surrounding the electrical connection between the or each electrode wire and the one or more connectors of the feedthrough. The medical implant may further comprise a flexible sleeve which surrounds at least part of the lead connector. The electrode lead may comprise a lead cover arranged to surround a portion of the electrode lead. The lead cover or flexible sleeve may comprise or essentially consist of silicone or pellethane. The flexible sleeve may reduce a strain associated with bending the flexible substrate for a given applied force.

[0035] In examples, the electrode lead further comprises an antenna wire extending at least partially along the electrode lead, and wherein the feedthrough comprises an antenna wire connector extending through the feedthrough to provide an electrical connection between the antenna wire and the electronics assembly.

[0036] In examples, the electrode lead has a length of up to about 100 millimetres, for example up to about 50 millimetres, for example up to about 30 millimetres, for example up to about 25 millimetres, for example up to about 20 millimetres, for example about 20 millimetres.

[0037] In examples, the tubular housing has an outer diameter of less than about 5 millimetres, for example between about 1 millimetre and about 5 millimetres, for example between about 1 millimetre and about 3 millimetres, for example about 3 millimetres.

[0038] In examples, the tubular housing has a length of up to about 30 millimetres, for example up to about 25 millimetres, for example up to about 20 millimetres, for example about 20 millimetres.

[0039] In examples, the medical implant is a battery-less implant.

[0040] In examples, the medical implant may further comprise a piezoelectric or triboelectric sensor element. The piezoelectric or triboelectric sensor element may be formed on the tubular housing, for example on the outer surface of the tubular housing, for example in a ring extending about the tubular housing. In other examples, the piezoelectric or triboelectric sensor element may be formed on the end cap, feedthrough, cover or other part of the medical implant. The piezoelectric or triboelectric sensor element may be connected to the electronics assembly within the tubular housing through the end cap in the same manner as the electrode. The piezoelectric or triboelectric sensor element may be used for sensing one or more parameters, for example physiological parameters such as such as body temperature, blood pressure, or heart rate. In some examples, the medical implant comprises a piezoelectric or triboelectric insert on the tubular housing, end cap or other location. The piezoelectric or triboelectric insert may be used for power harvesting, for example to generate electrical power from movement and / or forces applied to the piezoelectric or triboelectric insert at the implantation site.

[0041] According a further aspect of the invention there is provided a medical implant, for example a neurostimulator or diagnostic implant, comprising: a tubular housing, an end cap attached to an end of the tubular housing by a weld ring to hermetically seal the end of the tubular housing, and an electronics assembly housed within the tubular housing, wherein the weld ring is electrically connected to the electronics assembly and forms an electrode for sensing and / or stimulation.

[0042] In examples, the weld ring is attached to the tubular housing. In examples, the end cap comprises a second weld ring attached to the weld ring. In examples, the weld ring and the second weld ring together forming the electrode for sensing and / or stimulation.

[0043] In examples, the end cap is a metallic end cap, and wherein the end cap is electrically connected to the electronics assembly such that the end cap is part of the electrode.

[0044] In examples, the tubular housing further comprises a ring electrode formed on an outer surface of the tubular housing, and wherein the ring electrode is electrically connected to the electronics assembly via a conductive track in the end cap.

[0045] In examples, the tubular housing further comprises a ring electrode formed on an outer surface of the tubular housing. In such examples, the ring electrode may be electrically connected to the electronics assembly via a conductive track in the end cap. The conductive track may extend through the end cap and be electrically insulated from the end cap.

[0046] In examples, the medical implant further comprises an electrode lead extending from the end of the tubular housing. The electrode lead comprises one or more electrodes and one or more corresponding electrode wires, and wherein the end cap comprises one or more connectors for connecting the lead wires to the electronics assembly.

[0047] In examples, the electrode lead further comprises an antenna wire extending at least partially along the electrode lead. In such examples, the end cap comprises an antenna wire connector extending through the end cap to provide an electrical connection between the antenna wire and the electronics assembly.

[0048] In examples, the one or more electrodes are operable for one or more of: sensing a parameter of the patient when the medical implant is implanted, for example a physiological parameter, a vital sign, or a bioimpedance, detecting a neural signal of a patient's nerve when the medical implant is implanted, providing neural or non-neural stimulation to the patient when the medical implant is implanted.

[0049] According to a further aspect of the invention, there is provided a method of assembling a medical implant, for example a neurostimulator or diagnostic implant, comprising: providing a tubular housing, the tubular housing comprising a ceramic material and having a metallic weld ring attached to a first end of the tubular housing; providing an electronics assembly having a printed circuit board, PCB, and a metallic end cap attached to one end of the PCB; inserting the electronics assembly into the tubular housing; and welding the metallic end cap to the metallic weld ring.

[0050] In examples, the tubular housing has a second metallic weld ring attached to a second end of the tubular housing, wherein the electronics assembly comprises a second metallic end plug at an opposite end to the metallic end plug, and wherein the method further comprises welding the second metallic end cap to the second weld ring.

[0051] In examples, the second metallic end plug comprises one or more connectors extending therethrough, and wherein an electrode lead is attached to the second metallic end plug.

[0052] In examples, the connection between the metallic end cap and the metallic weld ring forms a hermetic seal. In examples, the connection between the second metallic end cap and the second weld ring forms a hermetic seal.

[0053] In examples, the metallic end cap and / or the second metallic end cap comprises a metallic weld ring and a ceramic body received within the metallic weld ring. The ceramic body may be joined to the metallic weld ring, for example by brazing or bonding.

[0054] In examples, the tubular housing comprises an electrode on an outer surface of the tubular housing and an electrode track extending from the electrode towards the first end, and wherein the metallic end cap comprises a conductive track extending through the metallic end cap and electrically insulated from the metallic end cap, and wherein the method comprises joining the electrode track to the conductive track at an outer surface of the end cap.

[0055] According to a further aspect of the invention, there is provided a method of assembling a medical implant, for example a neurostimulator or diagnostic implant, comprising: providing an electronics assembly having a printed circuit board, PCB, and a feedthrough comprising a ceramic body and a metallic insert disposed within a first weld ring, the metallic insert being in contact with the weld ring, the ceramic body comprising connectors extending through the ceramic body that are joined to the PCB on an internal side, and the metallic insert having a connecting pin extending therefrom and joined to the PCB on an internal side, providing a tubular housing having a second weld ring joined to an end of the tubular housing, inserting the electronics assembly into the tubular housing, and welding the first weld ring to the second weld ring to form an electrode in electrical connection with the PCB via the connecting pin.

[0056] In examples, the method further comprises attaching an electrode lead to the feedthrough. In examples, the electrode lead comprises one or more electrode wires that are electrically coupled to the connectors of the feedthrough.

[0057] In examples, the method further comprises sealing an end cap in an end of the tubular housing opposite to the feedthrough. In examples, the end cap engages the electronics assembly such that the PCB is sandwiched between the feedthrough and the end cap. In examples, the electronics assembly comprises a plug arranged to engage a socket of the end cap. In examples, the end cap is a feedthrough providing an electrical connection between one or more electrodes on the external surface of the tubular housing and the electronics assembly within the tubular housing.

[0058] According to another aspect of the invention there is provided a medical implant comprising a housing portion and an electronics assembly housed within the housing portion, and wherein the housing portion comprises a sensor element located on an external surface of the housing portion for detecting a parameter of a patient.

[0059] Preferably, the housing portion is made from an insulative material, such as a ceramic.

[0060] In one example, the sensor element comprises a piezoelectric or triboelectric material, for example an insert. The piezoelectric or triboelectric material is in electrical connection with the electronics assembly. The piezoelectric or triboelectric material is operable to detect a parameter of the patient, for example a physiological parameter such as body temperature, blood pressure or heart rate. The housing portion may include a tubular housing and an end cap sealing one end of the tubular housing. The piezoelectric or triboelectric material may be formed on an external surface of the tubular housing, and / or on the end cap. In some examples, the piezoelectric or triboelectric material may be used for power harvesting, for example to generate electrical power from movement and / or forces applied to the piezoelectric or triboelectric material at the implantation site.

[0061] In other examples, the sensor element may comprise one or more electrodes, such as metal electrodes. The electrodes may be provided in recesses on an external surface of the housing portion. The housing portion may be tubular, and the electrodes may extend circumferentially about the external surface of the housing portion, for example as ring electrodes. The electrodes may comprise the same material or different materials.

[0062] In some examples, the sensor element comprises first and second electrodes forming an interdigitated electrode pair. The electrodes may be provided in recesses on an external surface of the housing portion. The housing portion may be tubular, and the electrodes may extend circumferentially about the external surface of the housing portion, for example as ring electrodes. The electrodes may comprise the same material or different materials. The housing portion may comprise a second sensor element comprising a second interdigitated electrode pair. The or each interdigitated electrode pair may be operable as a differential bioimpedance sensor. In examples, a first interdigitated electrode pair may comprise a first metal, such as gold, and a second interdigitated electrode pair may comprise a second metal, such as platinum. Bioimpedance measurements taken by the two interdigitated electrode pairs may be used to determine a biochemical parameter at the implantation site, such as the presence and / or concentration of a chemical, for example proteins, alcohol, and glucose.

[0063] In various examples, the medical implant includes a plurality of electrodes for detecting a bioimpedance of tissue and fluid at the implantation site. The detected bioimpedance may be used for determining various parameters of the patient, including but not limited to blood glucose content (glycemia) and tissue composition (fat, water, etc...).

[0064] According to another aspect of the invention there is provided a housing portion for a medical implant, for example a neurostimulator or diagnostic implant, the housing portion comprising: a ceramic tubular housing for housing an electronics assembly, the ceramic tubular housing having a first end with a first mating face; and a metallic connecting ring having a second end with a second mating face, wherein the second mating face is brazed to the first mating face to form a flush joint between the metallic connecting ring and the ceramic tubular housing such that the first end and the second end form a level external surface of the housing portion.

[0065] The metallic connecting ring may be a weld ring.

[0066] The first end and the second end may form a level internal surface of the housing portion.

[0067] The first end may comprise a first recess defining at least part of the first mating face.

[0068] The second end may comprise a second recess defining at least part of the second mating face.

[0069] The first recess may extend around the circumference of the first end to form a first overhang portion.

[0070] The second recess may extend around the circumference of the second end to form a second overhang portion.

[0071] The first overhang portion may have an external diameter less than an external diameter of the remainder of the first end. The second overhang portion may have an external diameter less than an external diameter of the remainder of the second end.

[0072] The first overhang portion may have an internal diameter greater than an internal diameter of the remainder of the first end. The second overhang portion may have an internal diameter greater than an internal diameter of the remainder of the second end.

[0073] The external diameter of the housing portion may be equal at the first end and the second end.

[0074] A terminal face of the first overhang portion may abut a terminal face of the second overhang portion. Braze material may fill the first recess and / or the second recess.

[0075] The braze material may form part of the level external surface of the housing portion.

[0076] The braze material may form part of an internal surface of the housing portion.

[0077] The first overhang portion may have an undulating profile. The second overhang portion may have a correspondingly shaped undulating profile to engage the first overhang portion.

[0078] The undulating surface and correspondingly shaped undulating surface of the second end may be smooth or jagged, for example serrated.

[0079] A terminal face of the first overhang portion may be stepped so that the first overhang portion has a toothed profile. The second overhang portion may have a correspondingly shaped toothed profile to engage the first overhang portion.

[0080] The first recess may be configured to accommodate the second overhang portion.

[0081] The second recess may be configured to accommodate the first overhang portion.

[0082] One of the first overhang portion and the second overhang portion may surround the other of the first overhang portion and the second overhang portion.

[0083] The first overhang portion may have an external diameter less than an external diameter of a remainder of the first end. The second overhang portion may have an internal diameter that is greater than the internal diameter of a remainder of the second end.

[0084] The second overhang portion may have an external diameter less than an external diameter of a remainder of the second end. The first overhang portion may have an internal diameter that is greater than the internal diameter of a remainder of the first end.

[0085] Brazing material may be disposed between overlapping portions of the first overhang portion and the second overhang portion.

[0086] The first end may comprise a first set of teeth defining the first mating face.

[0087] The second end may comprise a second set of teeth defining the second mating face.

[0088] The first end may comprise a first set of teeth and a first set of sockets which together define the first mating face. The second end may comprise a second set of teeth and a second set of sockets which together define the second mating face.

[0089] The first set of teeth and the second set of teeth may interlock.

[0090] The housing portion may be configured such that when the metallic connecting ring is coupled to the ceramic tubular housing, the first set of teeth and the second set of teeth interlock.

[0091] Brazing material may be disposed between the first mating face and the second mating face.

[0092] The second set of teeth may project towards the ceramic tubular housing. The first set of teeth may project towards metallic connecting ring.

[0093] The first set of teeth may comprise a plurality of teeth members.

[0094] The second set of teeth may comprise a plurality of teeth members.

[0095] Each of the first set of teeth may comprise a curved outer surface with an external radius equal to the external radius of the ceramic tubular housing. Each of the second set of teeth may comprise a curved outer surface with an external radius equal to the external radius of the metallic connecting ring.

[0096] The housing portion may be configured such that interior surfaces of the first set of teeth and the second set of teeth align along the flush joint so that the first end and the second end form a level internal surface of the housing portion.

[0097] The first mating face and the second mating face may be configured to self-centre the metallic connecting ring and the ceramic tubular housing when the metallic connecting ring is translated towards the ceramic tubular housing during assembly of the housing portion.

[0098] The first mating face and the second mating face may be configured to axially align the metallic connecting ring with the ceramic tubular housing when an axial compressive force is applied to the housing portion.

[0099] The first end may comprise a first bevelled edge which defines the first mating face. The first mating face may which face a correspondingly shaped second bevelled edge defining the second mating face.

[0100] The first bevelled edge may be at a first angle to a longitudinal axis of the housing portion.

[0101] The second bevelled edge may be at a second angle to the longitudinal axis of the housing portion.

[0102] The first angle and the second angle may be supplementary angles.

[0103] The first bevelled edge may not be perpendicular to the longitudinal axis.

[0104] The second bevelled edge may not be perpendicular to the longitudinal axis.

[0105] The first bevelled edge may face the second bevelled edge along the whole length of the first and second bevelled edges.

[0106] The first angle may be between 125° and 145°. For example the first angle may be 135°. The second angle may be between 35° and 55°. For example, the second angle may be 45°.

[0107] The first angle may be between 35° and 55°. For example, the first angle may be 45°. The second angle may be between 125° and 145°. For example the second angle may be 135°.

[0108] The first bevelled edge may have a rounded rim.

[0109] The second bevelled edge may have a rounded rim.

[0110] The housing portion may further comprise an end cap coupled to the metallic connecting ring. The end cap may be coupled to the metallic connecting ring opposite the second end to seal an end of the housing portion, for example to hermetically seal the end of the housing portion.

[0111] The end cap may hermetically seal the end of the housing portion.

[0112] The end cap may comprise an electronics assembly housed within the ceramic tubular housing.

[0113] The end cap may comprise a conductive track extending from a position on an edge of the end cap that corresponds with the contact of the electrode track, to an inner surface of the end cap for connection with the electronics assembly within the tubular housing.

[0114] The end cap may be termed a first end cap. The housing portion may comprise a second end cap having any combination of the features discussed in association with the first end cap.

[0115] The first end of the ceramic tubular housing may be termed a front end of the ceramic tubular housing. The metallic connecting ring may be termed the first metallic connecting ring. The housing portion may include a second metallic connecting ring configured to be brazed to a rear end of the ceramic tubular housing. The second metallic connecting ring may have any of the features described herein in association with the first metallic connecting ring. For example, the second metallic connecting ring may be the same a the first metallic connecting ring rotated by 180°.

[0116] In a similar manner to how the first metallic connecting ring may be brazed to the front end of the ceramic tubular housing, the second metallic connecting ring may be brazed to the rear end of the ceramic tubular housing to form a flush joint between the second connecting ring and the ceramic tubular housing such that a front end of the second metallic connectingring and the rear end of the ceramic tubular housing form a level external surface of the housing portion.

[0117] The second end cap may be coupled to a rear end of the second metallic connecting ring to seal the rear end of the housing portion. The second end cap may or may not comprise the electronics assembly.

[0118] Either or both the first end cap or the second end cap may constitute a feedthrough, e.g., a front-end feedthrough, as described herein.

[0119] For example, a front end of the ceramic tubular housing may be brazed to a first end cap, such as a front-end feedthrough, while a rear end of the ceramic tubular housing may be brazed to a second end cap. Together, the first end cap and the second end cap may hermetically seal the electronics assembly within the housing portion.

[0120] The first end may terminate in a first flat rim which defines the first mating face. The first mating face may be oriented parallel to the radius of the ceramic tubular housing.

[0121] The second end may terminate in a second flat rim which defines the second mating face. The second mating face may be oriented parallel to the radius of the metallic connecting ring.

[0122] The first flat rim may be parallel to the second flat rim.

[0123] Together, the first end, the second end and the brazing material may define a level external surface of the housing portion.

[0124] An interior surface of the brazing material may be contiguous with interior surfaces of both the metallic connecting ring and the ceramic tubular housing, along the flush joint. The first end, the brazing material and the second end may form a level internal surface of the housing portion.

[0125] According to another aspect of the invention there is provided a method of assembling a housing portion for a medical implant, for example a neurostimulator or diagnostic implant, comprising the steps of: providing a ceramic tubular housing for housing an electronics assembly, the ceramic tubular housing having a first end with a first mating face; providing a metallic connecting ring having a second end with a second mating face; brazing the second mating face to the first mating face to form a flush joint between the metallic connecting ring and the ceramic tubular housing such that the first end and the second end form a level external surface of the housing portion; providing an end cap, comprising an electronics assembly, forsealing the first end of the ceramic tubular housing; inserting the electronics assembly into the ceramic tubular housing; and welding the end cap to the metallic connecting ring to form the housing portion.

[0126] The step of brazing the second mating face to the first mating face may be completed before the step of welding the end cap to the metallic connecting ring.

[0127] The first mating face and the second mating face may be configured to axially align the metallic connecting ring with the ceramic tubular housing when an axial compressive force is applied to the housing portion.

[0128] The first mating face may comprise a first bevelled edge the second mating face may comprises a second bevelled edge. The method may comprise moving the first mating face and the second mating face towards each other to axially align the ceramic tubular housing with the metallic connecting ring before brazing the second mating face to the first mating face.

[0129] The method may include a step of assembling the metallic connecting ring and the ceramic tubular housing and applying an axial compressive force to the metallic connecting ring and the ceramic tubular housing to axially align the metallic connecting ring with the ceramic tubular housing. Compressing the metallic connecting ring and the ceramic tubular housing together may slide the first bevelled edge against the second bevelled edge to centre the metallic connecting ring and the ceramic tubular housing.

[0130] The method may include laser welding the end cap to the metallic connecting ring to form the housing portion.

[0131] Steps of the method may be repeated to provide a housing portion with two end caps e.g., an end cap provided at both ends of the ceramic tubular housing.

[0132] The metallic connecting ring may be termed a first metallic connecting ring. The first end of the ceramic tubular housing may be termed the front end of the ceramic tubular housing. A rear end of the ceramic tubular housing may have a third mating face. The level external surface may be termed a first level external surface.

[0133] The method may include a step of providing a second metallic connecting ring having a front end with a fourth mating face.

[0134] The method may include a step of brazing the fourth mating face to the third mating face to form a flush joint between the second metallic connecting ring and the ceramic tubularhousing such that the front end of the second metallic connecting ring and the rear end of the ceramic tubular housing form a second level external surface of the housing portion.

[0135] The second level external surface of the housing portion may be level with the first level external surface of the housing portion.

[0136] The method may include a step of providing a second end cap for sealing the first end of the ceramic tubular housing.

[0137] The method may include a step of welding the second end cap to the second metallic connecting ring to seal the rear end of the ceramic tubular housing.

[0138] According to a further aspect of the invention there is provided a medical implant and a method of implanting a medical implant according to the appended claims.

[0139] According to a further aspect of the invention, there is provided a medical implant, for example a neurostimulator or diagnostic implant, comprising a housing assembly. The housing assembly comprises a tubular housing. The housing assembly further comprises an electronics assembly received at least partially within the tubular housing. The housing assembly further comprises a feedthrough comprising one or more feedthrough connectors connected to the electronics assembly. The one or more feedthrough connectors may extend to a terminal end of the feedthrough. The medical implant further comprises an electrode lead comprising one or more lead wires. The medical implant further comprises a lead connector configured to attach the electrode lead to the housing assembly. The lead connector has one or more conducting paths that electrically connect the lead wires to the one or more feedthrough connectors. The lead connector comprises a flexible substrate. The one or more conducting paths are provided in or on the flexible substrate. The flexible substrate is bendable to vary an angle between the electrode lead and the housing assembly.

[0140] Advantageously, the flexible substrate permits the electrode lead to bend relative to the housing assembly without compromising the integrity of the conductive paths that connect the lead wires to the feedthrough connectors. Therefore, the electrode lead and the housing assembly can each be implanted in the patient in a beneficial orientation. In particular, the electrode lead can be implanted at a target anatomical site, for example at or near a nerve, and the housing assembly can be implanted at a convenient position and orientation under the skin.

[0141] In some examples, the housing assembly includes a wireless power receiver, including an antenna, that receives power transmitted from an external device (e.g., a wearable). Beneficially, the flexible substrate allows the housing assembly to be implanted approximatelyparallel to the skin surface so as to provide good antenna orientation with low attenuation of the transmitted power. Meanwhile, the flexible substrate permits the electrode lead to extend from the housing assembly at various angles without the need for a curved path to avoid damage to the conductors. For example, the electrode lead may extend perpendicularly to the housing portion, or at an acute or obtuse angle relative to the housing portion, to reach the target anatomical site.

[0142] In examples, the flexible substrate may be a flexi-PCB. In examples, the flexible substrate may be a 2D PCB, which may be a flat moulded part with electrical tracks formed in a plane within the moulded part.

[0143] The feedthrough may comprise an end cap arranged to seal an end of the tubular housing. The one or more feedthrough connectors may each project through the end cap to enable electrical connection to the electronics assembly.

[0144] The flexible substrate may comprise or essentially consists of a flexible PCB. In examples, the flexible substrate may be a 2D PCB, which may be a flat moulded part with electrical tracks formed in a plane within the moulded part.

[0145] The one or more conducting paths may be arranged in a common plane which is substantially perpendicular to a longitudinal axis of the housing assembly.

[0146] The lead connector may be elongate. The lead connector may extend between: a first end proximal to the housing assembly; and a second end distal from the housing assembly, along a length of the lead connector.

[0147] The first end of the lead connector may be attached to the housing assembly. The first end of the lead connector may be aligned such that the first end is substantially perpendicular to the longitudinal axis of the housing assembly.

[0148] The electrode lead may be coupled to the second end of the lead connector. The electrode lead may be flexible.

[0149] The one or more lead wires may be coupled to the second end of the lead connector in a staggered arrangement.

[0150] Each of the one or more lead wires may be attached at a respective attachment point to a second end of the flexible substrate. The attachment points may be arranged such that for all directly neighbouring lead wires of the one or more lead wires, the attachment points are positioned at different longitudinal positions along the flexible substrate.

[0151] The length of the lead connector may be sufficient for the lead connector to project over a peripheral edge of the housing assembly.

[0152] The lead connector may extend radially from a front end of the housing assembly.

[0153] The flexible substrate may be operable to deflect between 30° and 250° relative to the housing portion, for example ±90° relative to the housing portion . In examples, in a nondeflected state the flexible substrate extends radially away from the housing portion (i.e., at 90 degrees to the housing portion and is deflectable in one direction up to 90 degrees to lie against the housing portion, and in the other direction up to 250 degrees. In some examples the flexible substrate is deflectable ±90° so that it can be deflected between a position in which it lays against the housing portion and a position in which it is parallel to the housing portion.Accordingly, in combination with rotation of the medical implant, the electrode lead can extend in any direction relative to the housing portion.

[0154] In examples, the flexible substrate may be deflectable at least between a position in which it lays against the housing portion and is parallel thereto, and a position in which it extends from the end of the housing portion and parallel to the housing portion (i.e., projecting along the longitudinal axis of the housing portion).

[0155] The lead connector may comprise an attachment plate which is coupled to the housing assembly and to the flexible substrate. The attachment plant may be coupled to the housing assembly and to the flexible substrate to attach the lead connector to the housing assembly.

[0156] The one or more feedthrough connectors may comprise a plurality of pins which are attached to the attachment plate and electrically connect the feedthrough to the flexible substrate.

[0157] The attachment plate may comprise or essentially consists of a rigid substrate having one or more conductive traces that electrically connect the one or more feedthrough connectors to the one or more conducting paths of the flexible substrate.

[0158] The one or more conducting paths of the flexible substrate may electrically connect each of the one or more conductive traces of the rigid substrate to a respective one of the one or more lead wires.

[0159] The rigid substrate may comprises or essentially consist of a rigid PCB.

[0160] The flexible substrate may have a first end and a second end. The first end may be opposite to the second end. The first end of the flexible substrate may be coupled to theattachment plate. The second end of the flexible substrate may be coupled to the electrode lead such that each of the one or more lead wires are connected to a respective one of the one or more conducting paths.

[0161] The medical implant may further comprise a flexible sleeve which surrounds at least part of the lead connector.

[0162] The electrode lead may comprise a lead cover arranged to surround a portion of the electrode lead.

[0163] The lead cover may comprise or essentially consist of silicone or pellethane.

[0164] The lead cover may surround the second end of the flexible substrate.

[0165] The flexible sleeve may comprises or essentially consist of silicone or pellethane.

[0166] The flexible sleeve may reduce a strain associated with bending the flexible substrate for a given applied force.

[0167] Each of the one or more lead wires may comprise an electrode for neurostimulation.

[0168] The medical implant may include one or more anti-migration members. The antimigration members may be provided on the tubular housing and / or on the electrode lead. The anti-migration members may function to hold the medical implant in position in the patient’s tissue. The anti-migration members may be configured to deploy during implantation of the medical implant in the patient.

[0169] The tubular housing may be a ceramic tubular housing for housing an electronics assembly. The housing assembly may comprise a housing portion. The housing portion may comprise: the ceramic tubular housing having a first end with a first mating face; and a metallic connecting ring having a second end with a second mating face. The second mating face may be brazed to the first mating face to form a flush joint between the metallic connecting ring and the ceramic tubular housing such that the first end and the second end form a level external surface of the housing portion.

[0170] The first end may terminate in a first flat rim which defines the first mating face. The second end may terminate in a second flat rim which defines the second mating face.

[0171] The first mating face and / or the second mating face may be oriented perpendicular to a longitudinal axis of the housing portion.

[0172] According to a further aspect of the invention, there is provided a delivery device for implanting the medical implant into a patient's tissue.

[0173] The delivery device may comprise a delivery sleeve. The medical implant may be received within the delivery sleeve.

[0174] According to a further aspect of the invention, there is provided a method of implanting a medical implant, for example a neurostimulator or diagnostic implant, in a patient. The method comprises the step of providing a delivery device for inserting the medical implant into the patient's tissue. The delivery device may comprise a delivery sleeve with the medical implant received therein. The method comprises the step of inserting part of the delivery sleeve into the patient’s tissue at an insertion angle and deploying the electrode lead from within the delivery sleeve into the patient’s tissue. The method comprises the step of changing the orientation of the delivery sleeve with respect to the patient’s tissue thereby bending the flexible substrate to vary an angle between the electrode lead and the housing assembly received within the delivery sleeve. The method comprises the step of deploying the housing assembly from within the delivery sleeve into the patient’s tissue at a deployment angle which is different to the insertion angle.

[0175] Prior to deploying the electrode lead from within the delivery sleeve into the patient’s tissue, the medical implant may be arranged within the delivery sleeve such that a front end of the housing assembly from which the electrode lead extends is directed oppositely to an opening of the delivery sleeve through which the electrode lead is deployed. Prior to deploying the electrode lead from within the delivery sleeve into the patient’s tissue, the electrode lead may overlie the housing assembly within the delivery sleeve and extend towards the opening.

[0176] According to a further aspect of the invention, there is provided a medical implant, for example a neurostimulator or diagnostic implant. The medical implant comprises a housing assembly. The housing assembly comprises a tubular housing and an electronics assembly received at least partially within the tubular housing. The medical implant further comprises an electrode lead extending from the housing assembly. The electrode lead comprises one or more lead wires electrically connected to the electronics assembly. The electrode lead comprises a helical portion.

[0177] The electrode lead may comprise at least one electrode. The helical portion may electrically connect the at least one electrode to the electronics assembly.

[0178] The electrode lead may comprise a lead cover which houses the helical portion.

[0179] The helical portion may have a first diameter which is substantially constant along a length of the helical portion. The helical portion may comprise a multi-filar array. For example, the helical portion may be formed using a multi-filar coil winder including a mandrel.

[0180] The helical portion may be a first helical portion. The electrode lead may further comprise a second helical portion. The second helical portion may have a second diameter. The second diameter may be greater than the first diameter.

[0181] The lead cover may house the second helical portion.

[0182] The electrode lead may comprise an outer cover which houses the second helical portion. The outer cover may comprise or essentially consist of silicone or pellethane. The outer cover may extend around a full circumference of the lead cover terminating at a position part-way along a length of the lead cover.

[0183] The electrodes may not be covered by the lead cover (and the outer cover where present).

[0184] The second helical portion may spiral around an outside of the first helical portion.

[0185] The first helical portion and the second helical portion may be co-axial.

[0186] The first helical portion may be operable as a wireless power antenna to supply power to the electronics assembly.

[0187] The second helical portion may be operable as a wireless power antenna to supply power to the electronics assembly.

[0188] The electrode lead may be flexible.

[0189] The second helical portion may be external to the housing assembly.

[0190] According to a further aspect of the invention, there is provided a feedthrough assembly for a medical implant, for example a neurostimulator or diagnostic implant. The feedthrough assembly is attachable to an end of a tubular housing of the medical implant to seal the end of the tubular housing, in particular to hermetically seal the end of the tubular housing. The feedthrough comprises a body that is attachable to or in the end of the tubular housing, and one or more conductors moulded with the body and extending through the body from an internal side to an external side. On the internal side the conductors are connectable to an electronics assembly housed within the tubular housing. On the external side the conductors extend into an electrode lead extending from the feedthrough. In some examples the conductors comprise lead wires that extend along the electrode lead to one or more electrodes formed on 1the electrode lead. In other examples, the conductors comprise conductive traces that extend part way along the electrode lead, and are in turn coupled to lead wires that extend to electrodes. Advantageously, this avoids any connection (e.g., a welded or soldered connection) between the conductors (conductive trace and / or lead wires) in the electrode lead and the feedthrough, which might be a point of weakness during bending of the electrode lead.

[0191] According to a further aspect of the invention, there is provided a housing assembly for a medical implant, wherein the housing assembly comprises a tubular housing, an electronics assembly housed within the tubular housing, and a battery end cap attached to an end of the tubular housing. The battery end cap is configured to house one or more battery cells.

[0192] In examples, the battery end cap may comprise a tubular body with an open end, and the open end may be attached to an end of the tubular housing. In examples, an outer dimension (e.g., an outer diameter) of the battery end cap may be the same as the outer dimension (e.g., an outer diameter) of the tubular housing. In this way, when connected, the battery end cup is an extension of the tubular housing and forming a flush outer surface.

[0193] In examples, the battery end cap comprises a sealing plate arranged to seal the battery cells within the battery end cap. In examples, the battery cells are electrically insulated from the tubular body of the battery end cap, for example by an insulative layer surrounding the battery cells. In examples, the battery cells are hermetically sealed within the battery end cap, in particular by the sealing plate. In examples, the battery end cap is hermetically sealed to the tubular housing.

[0194] In examples, one or more terminals may extend from the battery cells and / or sealing plate to connect with the electronics assembly within the tubular housing. In particular, the one or more terminals may connect with corresponding connectors, terminals or contact pads on the electronics assembly as the battery end cap is attached to the tubular housing. Advantageously, the electronics assembly can thus be assembled within the tubular housing, and the battery end cap can then be attached to the end of the tubular housing and form an electrical connection with the electronics assembly.

[0195] In examples, the battery end cap may comprise an insulative material or a conductive material, in particular a metal. If the battery end cap comprises a conductive material it may be connected to the electronics assembly and act as an electrode, for example a sensing or stimulating electrode. In examples where the battery end cap is made of an insulative material,for example a ceramic, it may be attached to the tubular housing by a weld ring or by a metalceramic braze.

[0196] In examples, an end of the tubular housing and / or an end of the battery end cap may comprise a bevel, step, recess or similar to engage the other of the tubular housing or the battery end cap to create an alignment between the two.

[0197] In examples, the battery end cap may comprise a conductive material, for example a metal. In such examples the battery end cap may form a part of an antenna, for example an arm of a (RF) dipole antenna. The antenna may be a power receiving antenna for receiving wireless power from an external device. In examples, the conductive material may be insulated, for example on an internal and external side, to act as a charge storage body (e.g., a capacitor).

[0198] In examples, the one or more battery cells may comprise a chemical battery cell (e.g., lithium ion), or an atomic battery cell (e.g., a tritium battery), or it may comprise a high density capacitor (supercapacitor).

[0199] Advantageously, the packaging of the battery cells within the battery end cap provides for use of larger battery and / or more battery cells within the same space because there is no battery casing in addition to the battery end cap. This advantageously provides for housing a larger battery within the same space, therefore increasing the energy density.

[0200] Features described in conjunction with a particular example or aspect of the invention are to be understood to be applicable to any other aspect or example described herein unless incompatible therewith. For example, the tubular housing of one example may have the features associated with the ceramic tubular housing of another example. It will be understood that the housing assemblies of any aspect of the invention may include the features associated with the housing portions of any aspect of the invention.

[0201] According to another aspect of the present disclosure there is a provided a medical implant having an electrode lead, the electrode lead being configured to be received in a needle of a delivery device, the needle comprising an opening extending along one side of the needle, wherein the electrode lead comprises one or more keys protruding from a side of the electrode lead so as to extend into the opening in the needle when the electrode lead is received in the needle, the key cooperating with sides of the opening to restrict rotation of the electrode lead within the needle.

[0202] In examples, the key acts an anchoring or anti-migration feature. In examples, the key protrudes beyond the circumference of the needle. In other examples, the key extendsmaximally to the diameter of the needle, or such that an outer face the key is within the diameter of the needle.

[0203] In examples, the electrode lead comprises a tine protruding away from the electrode lead. The tine may be resiliently biased to an angled extending position directed proximally (e.g., towards a housing assembly to which the electrode lead is attached). The tine may provide an anchoring or anti-migration function. The tine may extend from the key, or from a location on the electrode lead spaced from the key.

[0204] In examples, the tine is held in a retracted position, against the electrode lead, by the needle. In particular, the tine is wider than the opening in the needle such that the tine is held against the side of the electrode lead when the tine is aligned with the needle. During implantation of the medical device the needle may be retracted relative to the electrode lead and the tine may resiliently deploy into a position in which it protrudes away from the electrode lead to provide an anchoring or anti-migration function.

[0205] In examples, the key(s) and the tine(s) are separate features formed on the electrode lead. In other examples, the or each key may be a base portion of a tine, such that the tine extends from the key.

[0206] In examples, the base portion (key) may have a first thickness in the radial direction of the electrode lead, and the tine may have a second thickness in the radial direction of the electrode lead (when the tine is held against the side of the electrode lead), the second thickness being less than the first thickness. In this example, the tine can be held in the retracted position by the needle while the key extends into or through the opening in the needle to restrict rotation of the electrode lead relative to the needle.

[0207] In examples, the electrode lead may comprise a plurality of keys. In examples, the electrode lead may comprise a plurality of tines. In examples, the electrode lead may comprise a plurality of keys and one or more tines. In examples, the key(s) and / or tine(s) are overmoulded onto the electrode lead. In other examples, the key(s) and / or tine(s) are attached, e.g., adhered, to the electrode lead. In other examples, the key(s) and / or tine(s) are formed as a part of the electrode lead (e.g., in a body of the electrode lead or in a sheath of the electrode lead).

[0208] In examples, the key(s) and / or the tine(s) may comprise a resiliently deformable material. In examples, the key(s) and / or the tine(s) may comprise a polymer or a metal. In examples, the key(s) and / or the tine(s) may comprise may comprise a silicone, a pellethane, or a polyurethane. In examples, the key(s) and / or the tine(s) may comprise a metallic part (e.g., atitanium or nitinol (nickel titanium). In examples, the metallic part may be covered (coated or sheathed) with a softer material such as a polymer (e.g., a silicone, a pellethane, or a polyurethane).

[0209] All of the features disclosed herein and / or all of the steps of any methods disclosed herein, may be combined in any order, except combinations where at least some of such features and / or steps are mutually exclusive.BRIEF DESCRIPTION OF THE DRAWINGS

[0210] Embodiments of the invention are described with reference to the accompanying drawings, in which:

[0211] FIG. 1A illustrates an implantable medical implant.

[0212] FIG. IB illustrates an implantation site of the medical implant.

[0213] FIG. 2A illustrates a side view of a housing portion of the medical implant.

[0214] FIG. 2B illustrates a perspective view of the housing portion of the medical implant.

[0215] FIG. 2C illustrates a cross-section of the housing portion of the medical implant.

[0216] FIG. 2D illustrates a flexible sleeve of the medical implant.

[0217] FIG. 3A illustrates details of a first example tubular housing of the medical implant.

[0218] FIG. 3B illustrates details of the tubular housing of FIG. 3 A.

[0219] FIG. 4A illustrates a first example rear-end feedthrough of the medical implant.

[0220] FIG. 4B illustrates a connector of the rear-end feedthrough of FIG. 4A.

[0221] FIG. 4C illustrates an end cap of the rear-end feedthrough of FIG. 4A.

[0222] FIG. 4D illustrates further details of the rear-end feedthrough of FIG. 4A.

[0223] FIG. 5A illustrates an electronics assembly of the medical implant at an initial step of assembling the medical implant.

[0224] FIG. 5B illustrates the tubular housing of the medical implant at an initial step of assembling the medical implant.

[0225] FIG. 5C illustrates assembly of the end cap and the tubular housing at an initial step of assembling the medical implant.

[0226] FIG. 5D illustrates assembly of the electronics assembly and the tubular housing to form the housing portion of the medical implant.

[0227] FIG. 6A illustrates a second example housing portion of a medical implant.

[0228] FIG. 6B illustrates the tubular housing of the housing portion of FIG. 6A.

[0229] FIG. 7A illustrates an end cap of the housing portion of FIG. 6A.

[0230] FIG. 7B illustrates the end cap of the housing portion of FIG. 6A.

[0231] FIG. 8 illustrates assembly of the housing portion of FIG. 6A.

[0232] FIG. 9 illustrates a third example housing portion of a medical implant.

[0233] FIG. 10 illustrates assembly of the housing portion of FIG. 9.

[0234] FIG. 11 illustrates a fourth example of the housing portion of a medical implant.

[0235] FIG. 12 illustrates assembly of the housing portion of FIG. 11.

[0236] FIG. 13 illustrates an example medical implant with a piezoelectric sensor element.

[0237] FIG. 14A illustrates details of an alternative tubular housing of the medical implant.

[0238] FIG. 14B illustrates details of an alternative tubular housing of the medical implant.

[0239] FIG. 15A illustrates a front-end feedthrough of the medical implant.

[0240] FIG. 15B illustrates the front-end feedthrough.

[0241] FIG. 15C illustrates an aspect of the subject matter in accordance with one embodiment.

[0242] FIG. 15D illustrates connection of the front-end feedthrough to a PCB of the medical implant.

[0243] FIG. 16 illustrates attachment of the electrode lead to the housing portion to assemble the medical implant.

[0244] FIG. 17 illustrates a delivery device for implanting the medical implant in a patient's tissue.

[0245] FIG. 18 illustrates a cross-section of a housing portion for a medical implant.

[0246] FIG. 19 illustrates a cross-section of another example of a housing portion for a medical implant.

[0247] FIG. 20 illustrates a cross-section of another example of a housing portion for a medical implant.

[0248] FIG. 21 A illustrates an exploded view of another example of a housing portion for a medical implant.

[0249] FIG. 21B illustrates the housing portion of FIG. 21 A.

[0250] FIG. 22 illustrates a cross-section of another example of a housing portion for a medical implant.

[0251] FIG. 23 illustrates a cross-section of another example of a housing portion for a medical implant.

[0252] FIG. 24 illustrates a cross-section of another example of a housing portion for a medical implant.

[0253] FIG. 25 illustrates a method of assembling a housing potion for a medical implant.

[0254] FIG. 26 illustrates a delivery device for implanting the medical implant in a patient's tissue.

[0255] FIG. 27A illustrates a medical implant with a battery in a disassembled state.

[0256] FIG. 27B illustrates the medical implant of FIG. 27A in an assembled state.

[0257] FIG. 28 illustrates an implantable medical implant.

[0258] FIG. 29 shows an enlarged view of a front end of the medical implant of FIG. 28.

[0259] FIG. 30 shows the front end of the medical implant of FIG. 28 in a deformed configuration.

[0260] FIG. 31 shows a cross-sectional view of a housing assembly of the medical implant of FIG. 28 in isolation from other components of the medical implant.

[0261] FIG. 32 illustrates the medical implant of FIG. 28 and shows a flexible sleeve of the medical implant.

[0262] FIG. 33 illustrates an example feedthrough of the medical implant of FIG. 28.

[0263] FIG. 31 illustrates part of an electrode lead of a medical implant.

[0264] FIG. 32 illustrates part of an electrode lead of a medical implant.

[0265] FIG. 33 illustrates a delivery device for implanting a medical implant, such as the medical implant of FIG. 28, into a patient's tissue.

[0266] FIG. 37 illustrates a method of implanting a medical implant, such as the medical implant of FIG. 28, in a patient.

[0267] FIGS. 38A-38C illustrate an example electrode lead with a key and a tine, and a part of the delivery device of FIG. 17 or FIG. 26.DETAILED DESCRIPTION

[0268] FIG. 1A illustrates a medical implant 100. In examples, the medical implant 100 may be a neurostimulator implant and / or a diagnostic implant. The medical implant 100 comprises a housing portion 102 and an elongate electrode lead 104. The housing portion 102 may house an electronics assembly of the medical implant 100, as described further hereinafter. For example, the electronics assembly may include a printed circuit board (PCB), a wireless communications receiver / transmitter, a wireless power receiver, and / or sensor electronics. In examples, the housing portion 102 is hermetically sealed.

[0269] The electrode lead 104 extends from the housing portion 102 and is flexible. The electrode lead 104 includes at least one electrode 106a, in this example four electrodes 106a, 106b, 106c, 106d. In other examples, the electrode lead 104 may comprise one, two, three, five, six, or more electrodes. The electrodes 106a, 106b, 106c, 106d are spaced along the length of the electrode lead 104, particularly at an end of the electrode lead 104 opposite to the housing portion 102. The electrodes 106a, 106b, 106c, 106d are connected to the electronics within the housing portion 102. The electrodes 106a, 106b, 106c, 106d are metal, preferably a platinumiridium alloy or titanium.

[0270] In examples, the electrodes 106a, 106b, 106c, 106d are operated, by the electronics assembly housed in the housing portion 102, to provide electrical stimulation to stimulate a nerve of the patient. In other examples, the electrodes 106a, 106b, 106c, 106d are operated, by the electronics assembly housed in the housing portion 102, to sense or detect neural signals. In other examples, the electrodes 106a, 106b, 106c, 106d are operated, by the electronics assembly housed in the housing portion 102, to detect other (non-neural) parameters of the patient, for example bioimpedance, differential bioimpedance, blood pressure, or heart rate. In examples, at least two of the electrodes 106a, 106b, 106c, 106d may comprise different materials, in particular different metals, and may be operated to detect a differential bioimpedance. In examples, the electrodes 106a, 106b, 106c, 106d are operable in a first mode to detect neural signals, and operable in a second mode to stimulate a nerve of the patient. In examples, some of the electrodes 106a, 106b, 106c, 106d are operable to detect neural signals, and others are operable to stimulate the nerve. In examples, some of the electrodes 106a, 106b, 106c, 106d are operable to detect / stimulate a nerve, and others are operable to sense other (non- neural) parameters. In examples, the medical implant 100 may be implantable to sense and / or stimulate the greater occipital nerve, the tibial nerve, the sacral nerve (e.g., to treat urinaryincontinence), or the vagus nerve (e.g., to regulate pancreatic secretion). In other examples, the medical implant 100 may be implantable to sense and / or stimulate the Hypoglossal nerve (including the distal branches within the genioglossus muscle) and / or the Phrenic nerve and / or the Ansa Cervicalis nerve, for example to detect and / or treat sleep apnea.

[0271] The electronics assembly of the medical implant 100 includes a signal generator for generating signals for the electrodes 106a, 106b, 106c, 106d. In examples, in operation the electrodes 106a, 106b, 106c, 106d are provided with an electrical signal, such as a current, to stimulate the nerve. In examples, the electrical signal may be a voltage-regulated stimulation. Such stimulation can provide relief for chronic pain, for example occipital neuralgia, intractable migraine, and / or other therapeutic benefits.

[0272] In other examples, the medical implant 100 may be a diagnostic implant, for example a neurodiagnostic implant, operable to detect one or more neural signals in a nerve. In such examples the electrodes 106a, 106b, 106c, 106d are operable to detect neural signals. The neural signals may be analysed for the purposes of detecting, monitoring and / or diagnosing a condition.

[0273] In other examples, the medical implant 100 may be a diagnostic implant operable to detect one or more physiological parameters of the patient, or patient vital signs, for example bioimpedance, differential bioimpedance, body temperature, heart rate, electromyography (EMG), electrocardiogram (ECG), respiration rate, blood pressure, and / or blood gas concentration (e.g., oxygen (oxygen saturation), carbon dioxide, carbon monoxide). Detecting bioimpedance may allow the medical implant 100 to detect certain other parameters relating to the tissue and fluid (e.g., blood) surrounding the electrode lead 104 when implanted, for example blood glucose levels.

[0274] In examples, the housing portion 102 may have an outer diameter of less than about 5 millimetres, for example between about 1 millimetre and about 5 millimetres, for example between about 1 millimetre and about 3 millimetres, for example about 3 millimetres. The housing portion 102 may have a length of up to about 30 millimetres, for example up to about 25 millimetres, for example up to about 20 millimetres, for example about 20 millimetres. In examples, the electrode lead 104 may have a diameter of between about 0.3 millimetres to about 1.5 millimetres, for example between about 0.5 millimetres and 1.3 millimetres, for example about 0.8 millimetres. The electrode lead 104 may have a length of up to about 200 millimetres, for example up to about 150 millimetres, for example up to about 120 millimetres,for example about 120 millimetres. The electrodes 106a, 106b, 106c, 106d may each have a length (along the electrode lead 104) of up to about 15 millimetres, for example up to about 10 millimetres, for example up to about 5 millimetres, for example about 3 millimetres. The electrodes 106a, 106b, 106c, 106d may be spaced from each other along the electrode lead 104 by at least 2 millimetres, for example at least 3 millimetres, for example at least 5 millimetres. However, it will be appreciated that the dimensions of the housing portion 102 would correspond to the size of the electronics assembly within the housing portion 102, and the length of the electrode lead 104 would correspond to the anatomy surrounding the targeted nerve, so a shorter or longer electrode lead 104 may be appropriate depending on the depth of the nerve within the patient's tissue.

[0275] FIG. IB shows the medical implant 100 once implanted in a patient. The medical implant 100 is positioned below the surface of the skin, in particular below the epidermis 108. The housing portion 102 may be positioned in the dermis 110 or in the subcutaneous tissue 112. Positioning the housing portion 102 in the subcutaneous tissue 112, at a relatively shallow implantation depth, may be beneficial to reduce damage and / or irritation to the patient. In addition, implanting the housing portion 102 in the subcutaneous tissue 112 may provide for efficient wireless power transfer due to the shorter distance and less intermediate tissue.

[0276] As illustrated, the electrode lead 104 extends from the housing portion 102, through the underlying tissue, in particular muscle 114, to a position proximal to the target nerve 116. The electrode lead 104 is positioned such that the electrodes (106a, 106b, 106c, 106d, see FIG. 1) are close to, or even in contact with, the nerve 116, and so the electrodes 106a, 106b, 106c, 106d can be used to sense neural signals of the nerve 116 and / or to stimulate the nerve 116, and / or to sense non-.

[0277] The medical implant 100 may also include one or more anti-migration members. The anti-migration members may be provided on the housing portion 102 and / or on the electrode lead 104 and function to hold the medical implant 100 in position in the patient’s tissue. The anti-migration members are deployed during the implantation procedure.

[0278] In examples, the medical implant 100 is battery-less, i.e., it does not have an integrated power source. An external device 118 can wirelessly power the medical implant 100. The external device 118 may additionally wirelessly communicate with the medical implant 100, in particular the electronics assembly in the housing portion 102. The medical implant 100 may contain a wireless communications receiver / transmitter for communicating with the externaldevice 118. The medical implant 100 may also have a processor or controller configured to operate the medical implant 100. The external device 118 may be positioned on the patient's skin proximal to the medical implant 100. The external device 118 may be adhered to the skin proximal to the medical implant 100. The external device 118 may be a wearable device.

[0279] FIG. 2A and FIG. 2B show a first example of the housing portion 102 of the medical implant 100 in more detail. As shown, the housing portion 102 includes a front-end 202 at which the electrode lead 104 is attached, and a rear-end 206 opposite to the front-end 202. The housing portion 102 includes a tubular housing 208 that is sealed at both ends as described hereinafter. In the described examples the tubular housing 208 is circular, but it will be appreciated that it may have a square or triangular tubular shape, or other tubular shape.

[0280] The rear-end 206 of the tubular housing 208 is closed by an end cap 218 as described further hereinafter. As illustrated, the electrode lead 104 is attached to the front-end 202 of the housing portion 102 by a lead connector 210. A front-end feedthrough 224, which is described in more detail below, is provided at a front end of the tubular housing 208. The lead connector 210 is a second end cap at the front-end 202. The lead connector 210 may be a multi-lumen connector. The front-end 202 of the housing portion 102 is provided with a first weld ring 212 and a second weld ring 214 that act to seal the front-end 202 of the tubular housing 208 as described further below.

[0281] As shown in FIG. 2D, a flexible sleeve 226 may be provided. As shown, the flexible sleeve 226 is wrapped about at least a part of the lead connector (which is obscured b the flexible sleeve 226 in FIG. 2D) and at least a part of the electrode lead 104. The flexible sleeve 226 may comprise silicone or pellethane. The flexible sleeve 226 may be configured to provide strain relief to the electrode lead 104, in particular the conductive wires of the electrode lead 104. This may permit bending of the electrode lead 104 close to the front end 202. For example, as shown in FIG. 2D, the electrode lead 104 may be folded over against the tubular housing 208 and the flexible sleeve 226 provides strain relief for the conductors within the electrode lead 104.

[0282] Electrodes 216a, 216b, 216c, 216d are formed on the outer surface of the tubular housing 208. In this example, the electrodes 216a, 216b, 216c, 216d are ring electrodes extending circumferentially about the outer surface of the tubular housing 208. As explained further hereinafter, the electrodes 216a, 216b, 216c, 216d are connected to the electronics assembly within the tubular housing 208 through a feedthrough provided at the rear-end 206 ofthe housing portion 102. The electrodes 216a, 216b, 216c, 216d may be used to sense one or more parameters of the patient, and / or to provide stimulation, and / or for powering the medical implant 100 before and during delivery, as described further hereinafter.

[0283] As shown in FIG. 2C, an electronics assembly is housed within the tubular housing 208. In particular, a PCB 220 is housed within the tubular housing 208. The PCB 220 extends between the front-end 202 and the rear-end 206 and is supported at both ends. The PCB 220 includes various electronics components mounted to one or both sides of the PCB 220, including for example a processor or controller. An antenna 222 is also housed within the tubular housing 208. The antenna 222 is helical and wound around the PCB 220. The antenna 222 may be a wireless power antenna adapted to receive wireless power transmitted from the external device 118 illustrated in FIG. IB. In other examples, the electronics assembly may include more than one antenna within the tubular housing 208. In examples, there may be multiple wireless power antennas for receiving wireless power, for example at different wavelengths so that wireless power transmission can be improved. In examples, the electronics assembly may also include a wireless communications antenna within the tubular housing 208, although in this example the wireless communications antenna is provided in the electrode lead 104 as described further below.

[0284] The tubular housing 208 is formed of an electrically insulative material, preferably a ceramic material, in particular zirconia. The second weld ring 214 is attached to the front-end 202 of the tubular housing 208. The second weld ring 214 is preferably metal, in particular a platinum-iridium alloy or titanium. The second weld ring 214 is joined to the tubular housing 208, for example by adhesive, welding, or brazing. The second weld ring 214 forms a hermetic seal between the second weld ring 214 and the tubular housing 208. The first weld ring 212 is metallic, in particular a platinum-iridium alloy or titanium, and is joined to the second weld ring 214, preferably by welding. As explained further below, a front-end feedthrough 224 is provided in the first weld ring 212 that seals the housing portion 102. The lead connector 210 attaches the electrode lead 104 to the front-end feedthrough 224. The front-end feedthrough 224 provides an electrical connection between the electrode lead 104 and the PCB 220 within the housing portion 102. The front-end feedthrough 224 also acts as an end cap at the front-end 202 of the medical implant 100.

[0285] In alternative examples, the tubular housing 208 may include a piezoelectric material, for example formed as an insert similar to the electrodes 216a, 216b, 216c, 216d. In alternativeexamples, the front-end feedthrough 224 may additionally or alternatively comprise a piezoelectric material. In these examples, the piezoelectric material is electrically connected with the PCB 220 in same manner as the electrodes 216a, 216b, 216c, 216d, as described below. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure, or heart rate.

[0286] FIG. 3 A to FIG. 4D illustrate the rear-end 206 of the medical implant 100, and the rear-end feedthrough that electrically connects the electrodes 216a, 216b, 216c, 216d to the electronics assembly (in particular the PCB 220 shown in FIG. 2C) within the tubular housing 208.

[0287] As shown in FIG. 3 A, the electrodes 216a, 216b, 216c, 216d are provided on the outside of the tubular housing 208. The electrodes 216a, 216b, 216c, 216d are metal, preferably a platinum-iridium alloy or titanium. The electrodes 216a, 216b, 216c, 216d are preferably formed in recesses or grooves formed in the tubular housing 208. The recesses or grooves do not extend through the thickness of the tubular housing 208 so there is no requirement to seal the electrodes 216a, 216b, 216c, 216d to the tubular housing 208 in order to maintain the hermeticity of the housing portion 102. In other examples, the electrodes 216a, 216b, 216c, 216d are attached to the outer surface of the tubular housing 208, for example by adhesive or by brazing.

[0288] The housing portion 102 also includes electrode tracks 302a, 302b, 302c, 302d that extend from the electrodes 216a, 216b, 216c, 216d towards the rear-end 206. The electrode tracks 302a, 302b, 302c, 302d are metal, preferably a platinum-iridium alloy or titanium. The electrode tracks 302a, 302b, 302c, 302d are preferably formed in recesses or grooves formed in the tubular housing 208. The recesses or grooves do not extend through the thickness of the tubular housing 208 (apart from at their ends - see FIG. 3B) so there is no requirement to seal the electrode tracks 302a, 302b, 302c, 302d to the tubular housing 208 in order to maintain the hermeticity of the housing portion 102. In other examples, the electrode tracks 302a, 302b, 302c, 302d are attached to the outer surface of the tubular housing 208, for example by adhesive, welding, or brazing.

[0289] As shown in FIG. 3B, the electrode tracks 302a, 302b, 302c, 302d extend through the tubular housing 208 to an inner surface of the tubular housing 208 to define contacts 304a, 304b, 304c, 304d. As explained below, the positions of the contacts 304a, 304b, 304c, 304d correspond to the position of the end cap 218, which is sealed into the end of the tubularhousing 208 and thereby seals any path through the thickness of the tubular housing 208 at the contacts 304a, 304b, 304c, 304d to maintain the hermeticity of the housing portion 102. Therefore, advantageously, the end cap 218 maintains a hermetic seal and also provides a feedthrough at the rear end for connecting the electrodes 216a, 216b, 216c, 216d to the electronics within the tubular housing 208.

[0290] As illustrated, the end cap 218 is received in the end of the tubular housing 208, and abuts against the inner surface of the tubular housing 208. The end cap 218 may be an end plug.

[0291] FIG. 4A illustrates the end cap 218 that is received in the rear-end 206 of the tubular housing 208 shown in FIG. 3A and FIG. 3B. The end cap 218 is shown in isolation in FIG. 4C. When assembled, the end cap 218 is sealed in the end of the tubular housing 208, for example by brazing, bonding or adhesive.

[0292] As shown, the end cap 218 includes a socket 408. In this example the socket 408 is square but in other examples the socket 408 may be circular or have another polygonal shape, such as triangular or hexagonal. The socket 408 is formed on an inner surface of the end cap 218 that faces the interior of the tubular housing 208 when assembled.

[0293] The end cap 218 includes conductive tracks 410a, 410b, 410c, 41 Od that extend from an edge (i.e., the circumferential surface) of the end cap 218 and terminate at contacts 412a, 412b, 412c, 412d positioned in the socket 408. In this example, the contacts 412a, 412b, 412c, 412d are formed on side walls of the socket 408, with one contact 412a, 412b, 412c, 412d on each of the four side walls of the socket 408. However, it will be appreciated that different numbers of contacts may be provided and arranged differently in the socket 408.

[0294] The conductive tracks 410a, 410b, 410c, 41 Od each have an end on the circumferential surface that corresponds to the positions of the contacts 304a, 304b, 304c, 304d on the tubular housing 208 shown in FIG. 3B. In particular, the conductive tracks 410a, 410b, 410c, 41 Od extend from the socket 408 in a radial direction, onto the circumferential surface, and then about the circumferential surface to a position where the ends are proximate to each other. The arrangement of the ends of the conductive tracks 410a, 410b, 410c, 41 Od matches the arrangement of the contacts 304a, 304b, 304c, 304d on the tubular housing 208 shown in FIG. 3B. In this way, when the end cap 218 is assembled with the tubular housing 208 an electrical path is formed from each electrode 216a, 216b, 216c, 216d on the tubular housing 208 to the contacts 412a, 412b, 412c, 412d in the socket 408.

[0295] As shown in FIG. 2C, FIG. 4A and FIG. 4B, a connector 204 is provided between the end cap 218 and the PCB 220. The connector 204 includes a PCB connector 402 that connects with the PCB 220. The PCB connector 402 includes a U-shaped opening that receives the PCB 220. The PCB connector 402 includes electrical contacts that correspond to electrical contacts on the PCB 220.

[0296] The connector 204 also includes a rod 406 extending from the PCB connector 402 with a plug 404 formed on the end. The plug 404 is shaped to match the socket 408 on the end cap 218. The plug 404 includes electrical contacts that correspond to the contacts 412a, 412b, 412c, 412d in the socket 408. The contacts on the plug 404 are connected to the contacts on the PCB connector 402, which in turn is connected to the PCB 220. In this way, when the connector 204 is assembled between the end cap 218 and the PCB 220 there are electrical connections provided between the electrodes 216a, 216b, 216c, 216d and the PCB 220.

[0297] In this way, the end cap 218 provides an electrical feedthrough at the rear-end 206 of the tubular housing 208 to connect the electrodes 216a, 216b, 216c, 216d on the external surface of the tubular housing 208 to the PCB 220 inside the tubular housing 208 while maintaining the hermeticity of the rear-end 206 of the housing portion 102.

[0298] As shown in FIG. 4D, a capacitor 414 may be positioned about the rod 406 of the connector 204. The capacitor 414 may be a foil capacitor. The capacitor 414 may be too large to mount directly to the PCB 220, so positioning it about the rod 406 provides efficient packaging of the capacitor 414 within the tubular housing 208 as the internal diameter of the tubular housing 208 can be used more effectively.

[0299] In some examples, the tubular housing 208 does not comprise the electrodes 216a- 216d or the conductive tracks 302a-302d and contacts 304a-304d, as described above. In such an example, the connector 204 may be used to mount the capacitor 414 to the PCB 220 via the plug 402. In examples, the capacitor 414 may be a high-capacity capacitor, for example a supercapacitor. Advantageously, mounting the capacitor 414 in this way allows the size of the capacitor 414 to be increased as it is not constrained by being mounted directly on the PCB 220. In particular, the capacitor 414 can be sized to conform to the internal diameter of the tubular housing 208. A larger capacitor provides a higher energy density, giving more power for short term use by the medical implant.

[0300] In alternative examples, the end cap 218 may comprise a piezoelectric material. The end cap 218 may be made entirely from piezoelectric material, or may comprise a layer ofpiezoelectric material on the external surface. In these examples, the piezoelectric material is electrically connected with the PCB 220. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure or heart rate.

[0301] In alternative examples, the connector 204 may connect with the end cap 218 in an alternative manner. For example, the connector 204 may include one or more sprung pins that engage the conductive tracks 410a, 410b, 410c, 41 Od on the end cap 218. In alternative examples, the end cap 218 may directly connect to the PCB 220. For example, the PCB 220 or end cap 218 may include one or more sprung pins that engage the other of the PCB 220 and the end cap 218 to form an electrical connection between the conductive tracks 410a, 410b, 410c, 41 Od and the PCB 220. In other examples, the PCB 220 may be received in a cut out or recess in the end cap 218 to form an electrical connection between the conductive tracks 410a, 410b, 410c, 410d and the PCB 220. The PCB 220 and the end cap 218 may form a friction-fit. In other examples, conductive pins may extend from one of the PCB 220 and the end cap 218 and engage sockets on the PCB 220 and the end cap 218.

[0302] FIG. 5 A to FIG. 5D illustrate assembly of the housing portion 102 shown in FIG. 2A to FIG. 4D.

[0303] As shown in FIG. 5A, an electronics assembly 502 is initially assembled. The electronics assembly 502 includes the PCB 220, the first weld ring 212, the front-end feedthrough 224 and the antenna 222. The connector 204 and capacitor 414 are also assembled with the PCB 220. The front-end feedthrough 224is attached, e.g., soldered, to the PCB 220. In particular, as described with reference to FIG. 15D below, the electrode connectors 1504a, 1504b, 1504c, 1504d, the lead antenna connector 1506, and the connecting pin 1508 may be attached, e.g., soldered, to the PCB 220. The first weld ring 212 is attached, e.g., brazed, to the front-end feedthrough 224.

[0304] As shown in FIG. 5B, the tubular housing 208 (with the electrodes 216a, 216b, 216c, 216d) is attached, e.g., brazed or welded, with the second weld ring 214 at the front-end 202. The tubular housing 208 includes a stepped end 504 over which the second weld ring 214 is received. The second weld ring 214 may be joined to the stepped end 504 and / or to the end face of the tubular housing 208 adjacent to the stepped end 504. Preferably, the second weld ring 214 is attached to the tubular housing 208 before the electronics assembly 502 is combinedwith the tubular housing 208 to prevent damage to the PCB 220 that may be caused by brazing the second weld ring 214 to the tubular housing 208.

[0305] As shown in FIG. 5C, the end cap 218 is assembled into the rear-end 206 of the tubular housing 208. The end cap 218 can be attached to the tubular housing 208 by adhesive or by brazing. The end cap 218 hermetically seals the rear-end 206 of the tubular housing 208. As described above, the end cap 218 provides an electrical connection between the electrodes on the outer surface of the tubular housing 208 and the socket 408 (see FIG. 4A) facing the interior of the tubular housing 208. The end cap 218 covers and seals against the contacts 304a, 304b, 304c, 304d on the inner surface of the tubular housing 208 (see also FIG. 3B).

[0306] Next, as shown in FIG. 5D, the electronics assembly 502 shown in FIG. 5A is inserted into the tubular housing 208. Once fully inserted the plug 404 of the connector 204 will engage the socket 408 of the end cap 218 at the rear-end 206 (see FIG. 4A). At this position, the first weld ring 212 will abut the second weld ring 214. The first weld ring 212 and the second weld ring 214 are joined to each other, for example by welding. This hermetically seals the front-end 202 of the housing portion 102. Together with the end cap 218 at rear-end 206, the housing portion 102 is thereby hermetically sealed with the electronics assembly 502 housed inside the tubular housing 208.

[0307] The plug 404 and socket 408, being square or polygonal, will help ensure alignment between the contacts 304a, 304b, 304c, 304d on the tubular housing 208 (see FIG. 3B) and the conductive tracks 410a, 410b, 410c, 410d on the end cap 218 (see FIG. 4A).

[0308] FIG. 6A to FIG. 8 illustrate a further example housing portion 602 of the medical implant 100. In this example, the rear-end 604 differs from the example described above. FIG. 6A illustrates the rear-end 604 of the housing portion 602, and FIG. 6B illustrates the rear-end 604 without the end cap 608. FIG. 7A and FIG. 7B illustrate the end cap 608 and FIG. 8 illustrates assembly of the housing portion 602.

[0309] As shown in FIG. 6A and FIG. 6B, the housing portion 602 includes a tubular housing 606 having a plurality of electrodes 610a, 610b, 610c, 610d formed on the outer surface of the tubular housing 606 in the same manner as described above. Electrode tracks 612a, 612b (only two visible in FIG. 6 A) extend from each electrode 610a, 610b, 610c, 61 Od, respectively, to contacts 616a, 616b (only two visible in FIG. 6B). The contacts 616a, 616b extend through the tubular housing 606 and protrude into the interior of the tubular housing 606.

[0310] An end cap 608 is provided in the rear-end 604 of the tubular housing 606. A weld ring 614 is provided to secure the end cap 608 to the tubular housing 606 as described further hereinafter. As described below, the end cap 608 provides an electrical connection between the contacts 616a, 616b and an electronics assembly housed within the tubular housing 606.

[0311] As illustrated, the end cap 608 is received in the end of the tubular housing 606, and abuts against the inner surface of the tubular housing 606. The end cap 608 may be an end plug.

[0312] As shown in FIG. 7A and FIG. 7B, the end cap 608 includes a ceramic body 702. The ceramic body 702 is electrically insulative and may be made from other electrically insulative materials, such as a polymer.

[0313] A plurality of conductive inserts 704a, 704b, 704c (three are visible in FIG. 7A but it will be appreciated that there are an equivalent number of conductive inserts to electrodes on the tubular housing) are provided in the ceramic body 702. The conductive inserts 704a, 704b, 704c each provide a conductive track analogous to those described above with reference to FIG. 3A and FIG. 3B.

[0314] Each conductive insert 704a, 704b, 704c includes a groove 712. When the end cap 608 is assembled into the rear-end 604 of the tubular housing 606 shown in FIG. 6A and FIG. 6B, the contacts 616a, 616b engage the grooves 712 and form an electrical connection between the conductive inserts conductive insert 704a, 704b, 704c and the electrodes 610a, 610b, 610c, 61 Od on the tubular housing 606.

[0315] Connecting pins 706a, 706b extend from the conductive inserts 704a, 704b, 704c into the interior of the tubular housing 606 (only two are shown in FIG. 7A but it will be appreciated that each conductive insert 704a, 704b, 704c comprises a connecting pin). The connecting pins 706a, 706b are connected to, for example soldered or welded to, PCB contacts 708a, PCB contacts 708b on the PCB 220. In this way, when the housing portion 602 is assembled an electrical connection is formed between the electrodes 610a, 610b, 610c, 61 Od and the PCB 220 via the electrode tracks 612a, 612b, the conductive inserts 704a, 704b, 704c, the connecting pins 706a, 706b, and the PCB contacts 708a, 708b. This assembly thereby provides a rear-end feedthrough.

[0316] As shown in FIG. 6A, FIG. 7A and FIG. 7B, the ceramic body 702 of the end cap 608 is joined to the tubular housing 606 via the weld ring 614. The weld ring 614 includes one or more keys 714 that engage grooves in the ceramic body 702. The weld ring 614 is brazed, welded or adhered to both the tubular housing 606 and to the ceramic body 702 duringassembly as described further below and preferably provides a hermetic seal. The keys 714 may align with the grooves 712 in the conductive inserts 704a, 704b, 704c, and the grooves may extend through the ceramic body 702, allowing assembly of the different parts and ensuring alignment.

[0317] As shown in FIG. 7B, the ceramic body 702 may include holes 710a, 710b, 710c, 710d that receive the connecting pins 706a, 706b in such a way that they are secured in the ceramic body 702 and electrically connected to the conductive inserts 704a, 704b, 704c. The connecting pins 706a, 706b may be adhered in the holes 710a, 710b, 710c, 71 Od, or welded or brazed in the holes 710a, 710b, 710c, 71 Od. The connecting pins 706a, 706b may be sealed into the holes 710a, 710b, 710c, 710d to maintain hermeticity.

[0318] In alternative examples, the tubular housing 606 may include a piezoelectric material, for example formed as an insert similar to the electrodes 610a, 610b, 610c, 61 Od. In alternative examples, the front-end feedthrough may additionally or alternatively comprise a piezoelectric material. In these examples, the piezoelectric material is electrically connected with the PCB 220 in same manner as the electrodes 610a, 610b, 610c, 61 Od, as described above. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure, or heart rate.

[0319] In alternative examples, the end cap 608 may comprise a piezoelectric material. The end cap 608 may be made entirely from piezoelectric material, or may comprise a layer of piezoelectric material on the external surface. In these examples, the piezoelectric material is electrically connected with the PCB 220. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure or heart rate.

[0320] FIG. 8 illustrates an assembly process of the medical implant 100 described with reference to FIG. 6A to FIG. 7B. As shown, initially an electronics assembly 802 is assembled by joining the ceramic body 702 to the PCB 220 in the manner described above. The front-end feedthrough 224 is attached to the opposite end of the PCB 220 as will be described further hereinafter.

[0321] The tubular housing 606 is provided with a weld ring 614 attached at the rear-end 604. The tubular housing 606 is also provided with the second weld ring 214 at the front-end 202 in the same manner as described with reference to FIG. 5 A to FIG. 5D.

[0322] The electronics assembly 802 is then assembled into the tubular housing 606 from the front-end 202. The ceramic body 702 will engage the weld ring 614 and the contacts 616a, 616b illustrated in FIG. 6B, creating the electrical connections described above. The ceramic body 702 can then be joined to the weld ring 614 to secure and seal the housing portion 602. The ceramic body 702 may be joined to the weld ring 614 by adhesive, welding or brazing, preferably forming a hermetic seal.

[0323] A cover, for example a wrap or the like, may be provided over the rear-end 604 to cover over the end cap 608.

[0324] At the front-end 202, the first weld ring 212 can be joined to the second weld ring 214 to secure and seal the front-end 202. The first weld ring 212 may be joined to the second weld ring 214 by adhesive, welding or brazing.

[0325] Advantageously, the design of the housing portion 602 and the assembly process described allow the final assembly steps, particularly any welding or brazing, to be conducted from the exterior of the tubular housing 606 and away from any electronics, helping to prevent accidental damage during manufacture.

[0326] FIG. 9 shows a further example housing portion 902 of the medical implant 100. This example is similar to that of FIG. 6A to FIG. 8, except that the electrode tracks 914a, 914b do not extend through the thickness of the tubular housing 906 but rather extend around the rear- end 904 and form an electrical connection with the PCB 220 through an end cap 908 as described below.

[0327] As shown in FIG. 9, the housing portion 902 includes a tubular housing 906 having a plurality of electrodes 912a, 912b, 912c, 912d formed on the outer surface of the tubular housing 906 in the same manner as described above. Electrode tracks 914a, 914b (only two visible in FIG. 9) extend from each electrode 912a, 912b, 912c, 912d, respectively, to arms 916 that extend around the rear-end 904. The arms 916 may be integral with the electrode tracks 914a, 914b, for example folded ends of the electrode tracks 914a, 914b. The arms 916 connect with connecting pins 918 that extend through an end cap 908 provided in the tubular housing 906. The arms 916 may be in contact with the connecting pins 918, or they may be soldered or welded to each other. In this way, the arms 916 and the connecting pins 918 each form a conductive track.

[0328] As illustrated, the end cap 908 is received in the end of the tubular housing 906, and abuts against the inner surface of the tubular housing 906. The end cap 908 may be an end plug.

[0329] A weld ring 910 is provided to join and seal the tubular housing 906 and the end cap 908. The connecting pins 918 are sealed into holes formed in the end cap 908, for example by adhesive or epoxy. In one example, the end cap 908 is formed of an electrically insulative material, for example ceramic or polymer. In another example, the end cap 908 is formed from a metal, for example platinum-iridium. In such an example, the connecting pins 918 are insulated from the end cap 908, for example by an insulative coating on the connecting pins 918 or by using an insulative tubular insert that surrounds the connecting pins 918 within the end cap 908. In such an example, the end cap 908 can be welded directly to the weld ring 910 on the tubular housing 906 to attach the end cap 908 to the tubular housing 906. Additionally, the end cap 908 may be electrically connected to the PCB 220 and act as an electrode, for example for sensing and / or stimulation.

[0330] The connecting pins 918 are connected to the PCB 220 in the same way as shown in FIG. 7A.

[0331] A cover, for example a wrap or the like, may be provided over the rear-end 904 to seal over the arms 916 and the connecting pins 918.

[0332] In alternative examples, the tubular housing 906 may include a piezoelectric material, for example formed as an insert similar to the electrodes 912a, 912b, 912c, 912d. In alternative examples, the front-end feedthrough may additionally or alternatively comprise a piezoelectric material. In these examples, the piezoelectric material is electrically connected with the PCB 220 in same manner as the electrodes 912a, 912b, 912c, 912d, as described above. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure, or heart rate.

[0333] In alternative examples, the end cap 908 may comprise a piezoelectric material. The end cap 908 may be made entirely from piezoelectric material, or may comprise a layer of piezoelectric material on the external surface. In these examples, the piezoelectric material is electrically connected with the PCB 220. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure or heart rate.

[0334] FIG. 10 shows assembly of the housing portion 902 shown in FIG. 9. As shown, an electronics assembly 1002 is assembled with the end cap 908 joined to the rear-end and the front-end feedthrough 224 joined to the front-end.

[0335] The tubular housing 906 is provided with the weld ring 910 and arms 916 at the rear- end, and the second weld ring 214 at the front-end.

[0336] The electronics assembly 1002 is then assembled into the tubular housing 906 from the front-end. Once assembled, the connecting pins 918 on the end cap 908 engage the arms 916 forming an electrical connection between the electrodes 912a, 912b, 912c, 912d and the PCB 220. The end cap 908 is then joined to the weld ring 910 to secure and seal the housing portion 902. The end cap 908 may be joined to the weld ring 910 by adhesive, welding, or brazing. The connecting pins 918 and arms 916 may be joined together, for example by soldering or welding.

[0337] At the front-end, the first weld ring 212 can be joined to the second weld ring 214 to secure and seal the front-end 202. The first weld ring 212 may be joined to the second weld ring 214 by adhesive, welding or brazing.

[0338] FIG. 11 shows a further example housing portion 1102 of the medical implant 100. This example is similar to that of FIG. 9 and FIG. 10 in that the electrode tracks 1114a, 1114b extend around the rear-end 1104 and form an electrical connection with the PCB 220 through an end cap 1108 as described below.

[0339] As shown in FIG. 11, the housing portion 1102 includes a tubular housing 1106 having a plurality of electrodes 1112a, 1112b formed on the outer surface of the tubular housing 1106 in the same manner as described above. In this example, there are two electrodes 1112a, 1112b. Electrode tracks 1114a, 1114b extend from each electrode 1112a, 1112b, respectively, to arms 1116 that extend around the rear-end 1104. The arms 1116 may be integral with the electrode tracks 1114a, 1114b, for example folded ends of the electrode tracks 1114a, 1114b. The arms 1116 connect with connecting pins 1118 that extend through an end cap 1108 provided in the tubular housing 1106. The arms 1116 may be in contact with the connecting pins 1118, or they may be soldered or welded to each other. In this way, the arms 1116 and the connecting pins 1118 each form a conductive track.

[0340] As illustrated, the electrode tracks 1114a, 1114b are received in recesses formed in the tubular housing 1106 and the weld ring 1110. The recess in the weld ring 1110 may have an insulating liner that electrically insulates the weld ring 1110 and the electrode tracks 1114a, 1114b. The insulating liner may be a parylene coating. The insulating liner may be a sleeve about each electrode track 1114a, 1114b, or a liner within the recesses formed in the weld ring 1110. In some examples, the electrode tracks 1114a, 1114b may be a flexi-PCB having aconductive part that is insulated where the electrode tracks 1114a, 1114b overly the weld ring 1110 to insulate them.

[0341] As illustrated, the end cap 1108 is received in the end of the tubular housing 1106, and abuts against the inner surface of the tubular housing 1106. The end cap 1108 may be an end Plug.

[0342] A weld ring 1110 is provided to join and seal the tubular housing 1106 and the end cap 1108. The weld ring 1110 is attached t the tubular housing 1106, for example by brazing. The connecting pins 1118 are sealed into holes formed in the end cap 1108, for example by adhesive or epoxy. In one example, the end cap 1108 is formed of an electrically insulative material, for example ceramic or polymer. In another example, the end cap 1108 is formed from a metal, for example platinum-iridium. In such an example, the connecting pins 1118 are insulated from the end cap 1108, for example by insulating sleeves 1120 as illustrated. In such an example, the end cap 1108 can be welded directly to the weld ring 1110 on the tubular housing 1106 to attach the end cap 1108 to the tubular housing 1106. Additionally, the end cap 1108 may be electrically connected to the PCB 220 and act as an electrode, for example for sensing and / or stimulation.

[0343] The connecting pins 1118 are connected to the PCB 220 in the same way as shown in FIG. 7A.

[0344] A cover, for example a wrap or the like, may be provided over the rear-end 1104 to seal over the arms 1116 and the connecting pins 1118.

[0345] In alternative examples, the tubular housing 1106 may include a piezoelectric material, for example formed as an insert similar to the electrodes 1112a, 1112b. In alternative examples, the front-end feedthrough may additionally or alternatively comprise a piezoelectric material. In these examples, the piezoelectric material is electrically connected with the PCB 220 in same manner as the electrodes 1112a, 1112b, as described above. The piezoelectric material may be used to detect a parameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure, or heart rate.

[0346] In alternative examples, the end cap 1108 may comprise a piezoelectric material. The end cap 1108 may be made entirely from piezoelectric material, or may comprise a layer of piezoelectric material on the external surface. In these examples, the piezoelectric material is electrically connected with the PCB 220. The piezoelectric material may be used to detect aparameter of the patient when the medical implant 100 is implanted, such as body temperature, blood pressure or heart rate.

[0347] FIG. 12 shows assembly of the housing portion 1102 shown in FIG. 11. As shown, an electronics assembly 1202 is assembled with the end cap 1108 joined to the rear-end and the front-end feedthrough 224 joined to the front-end and joining the electrode lead 104 to the electronics assembly 1202.

[0348] The tubular housing 1106 is provided with the weld ring 1110 and arms 1116 at the rear-end, and the second weld ring 214 at the front-end.

[0349] The electronics assembly 1202 is then assembled into the tubular housing 1106 from the front-end. Once assembled, the connecting pins 1118 on the end cap 1108 engage the arms 1116 forming an electrical connection between the electrodes 1112a, 1112b and the PCB 220. The end cap 1108 is then joined to the weld ring 1110 to secure and seal the housing portion 1102. The end cap 1108 may be joined to the weld ring 1110 by adhesive, welding, or brazing. The connecting pins 1118 and arms 1116 may be joined together, for example by soldering or welding. A silicone or epoxy cap may be provided over the connecting pins 1118 and the arms 1116 to seal them.

[0350] At the front-end, the first weld ring 212 can be joined to the second weld ring 214 to secure and seal the front-end 202. The first weld ring 212 may be joined to the second weld ring 214 by adhesive, welding or brazing.

[0351] The example of FIG. 13 is similar that of FIG. 11 and FIG. 12 and includes a tubular housing 1106 having an electrode 1112a formed on the outer surface. An electrode track 1114a extends from the electrode 1112a towards the rear-end 1104 and connects with a connecting pin 1118 to connect with the electronics assembly within the tubular housing 1106. The weld ring 1110 and end cap 1108 provide a hermetic seal at the rear-end 1104 and the connecting pin 1118 extends through the end cap 1108. The electrode track 1114a is insulated from the weld ring 1110 as described above. In this example, only a single electrode 1112a is provided but it will be appreciated that more than one electrode 1112a may be provided.

[0352] In this example, the housing portion 1102 includes a piezoelectric insert 1302. The piezoelectric insert 1302 is provided on the end cap 1108, for example attached to the end cap 1108. The piezoelectric insert 1302 is connected with a second connecting pin that extends through the end cap 1108 in the same way as the illustrated connecting pin 1118. The piezoelectric insert 1302 is thereby electrically connected to the electronics assembly within thetubular housing 1106. A silicone or epoxy cap may be provided over the connecting pin 1118 to seal it, and the piezoelectric insert 1302 may be only partially covered by silicone or epoxy cap so that a part of the piezoelectric insert 1302 remains exposed.

[0353] The piezoelectric insert 1302 may be used as a sensor element, for example to sense a physiological parameter of the patient, such as blood pressure or heart rate. In other examples, the piezoelectric insert 1302 may be used for energy harvesting, utilising forces and / or movements at the implantation site to generate electrical current for powering the medical implant.

[0354] In other examples, the piezoelectric insert 1302 may alternatively be a triboelectric insert that is used as a sensor element or for energy harvesting in the same manner as described above for the piezoelectric insert 1302.

[0355] FIG. 14A and FIG. 14B illustrate an alternative housing portion 1402 of the medical implant 100. In this example, the housing portion 1402 includes a first electrode 1408 and a second electrode 1410 formed on the outside of the housing portion 1402 as an interdigitated electrode pair. That is, the first electrode 1408 and the second electrode 1410 both include overlapping interdigitated formations, as illustrated. The first electrode 1408 and the second electrode 1410 extend about the circumference of the housing portion 1402. Similarly, the housing portion 1402 includes a third electrode 1412 and a fourth electrode 1414 formed on the outside of the housing portion 1402 as an interdigitated electrode pair. That is, the third electrode 1412 and the fourth electrode 1414 both include overlapping interdigitated protrusions, as illustrated. The third electrode 1412 and the fourth electrode 1414 extend about the circumference of the housing portion 1402.

[0356] In this example, each of the interdigitated electrode pairs, 1408 and 1410, and 1412 and 1414 may be used as a bioimpedance sensor. Together, the two sets of interdigitated electrode pairs 1408 and 1410, and 1412 and 1414 may provide a differential bioimpedance sensor to detect differences in bioimpedance at the first pair 1408 and 1410 and at the second pair 1412 and 1414. Differential bioimpedance may be used, for example, to detect a heart rate of the patient, a blood pressure of the patient, or a movement of the patient, such as a breathing rate.

[0357] The first electrode 1408 and the second electrode 1410 may comprise the same or different conductive materials, and the third electrode 1412 and the fourth electrode 1414 maycomprise the same or different conductive materials. The electrodes 1408 - 1414 are made from a metal, preferably a platinum-iridium alloy or titanium.

[0358] As with the examples described above, the electrodes 1408 - 1414 are each connected to an electrode track 1416a, 1416b, 1416c, 1416d, respectively. The electrode tracks 1416a, 1416b, 1416c, 1416d extend along the housing portion 1402 towards the rear-end 1404 and connect to the end cap 1406 in the same way as described above and hereinafter.

[0359] The electrodes 1408 - 1414 and the electrode tracks 1416a, 1416b, 1416c, 1416d are preferably formed in recesses in the housing portion 1402.

[0360] FIG. 15A to FIG. 15D illustrate the front-end of the medical implant 100 described above. FIG. 15 A to FIG. 15D are based on the example of FIG. 2A to FIG. 2C, but it will be appreciated that the front-end feedthrough 224 may be the same for any of the other examples described herein.

[0361] As shown in FIG. 15 A, the electrode lead 104 is connected to a lead connector 210 that is attachable to the housing portion 102 of the medical implant 100. The lead connector 210 is attached to the first weld ring 212, for example by adhesive or epoxy. The lead connector 210 may overlap a part of the first weld ring 212. A front-end feedthrough 224 is attached within the first weld ring 212. The front-end feedthrough 224 provides electrical connections between the electrode lead 104 (specifically the electrodes 106a, 106b, 106c, 106d, see FIG. 1A) and the PCB 220 within the tubular housing 208 while also sealing within the first weld ring 212 to provide a hermetic seal at the front-end 202 of the housing portion 102.

[0362] FIG. 15B shows the front-end feedthrough 224 in isolation. In this example, the frontend feedthrough 224 includes a ceramic body 1502, preferably zirconia. The front-end feedthrough 224 is attached to the first weld ring 212 by adhesive or preferably by brazing. The front-end feedthrough 224 is hermetically sealed to the first weld ring 212. The front-end feedthrough 224 is preferably cylindrical and matches the inner diameter of the first weld ring 212.

[0363] As shown in FIG. 15C, the electrode lead 104 comprises a sheath 1510. The sheath 1510 is flexible. The sheath 1510 is electrically insulative. Within the sheath 1510 are electrode wires 1512a, 1512b, 1512c, 1512d that extend along the electrode lead 104 and each connect to one of the electrodes 106a, 106b, 106c, 106d. It will be appreciated that the electrode lead 104 may have a different number of electrodes 106a, 106b, 106c, in which case the electrode lead 104 will have a corresponding number of electrode wires 1512a, 1512b, 1512c. The electrodelead 104 also includes an antenna wire 1514 extending at least partially along the electrode lead 104. The antenna wire 1514 may be used for wireless communications with the external device 118 shown in FIG. IB. Alternatively, the antenna wire 1514 is a segment of the receiving antenna which contributes to wireless power transfer with the external device 118 shown in FIG. IB.

[0364] Referring to FIG. 15B, the front-end feedthrough 224 includes electrode connectors 1504a, 1504b, 1504c, 1504d that extend longitudinally through the front-end feedthrough 224 and protrude on both sides. On the inside, the electrode connectors 1504a, 1504b, 1504c, 1504d are connected to the PCB 220 in the housing portion 102 as shown in FIG. 15D. In particular, the electrode connectors 1504a, 1504c, 1504d can be joined to the PCB 220 by attaching them to contacts 1518 formed on the PCB 220. The electrode connectors 1504a, 1504c, 1504d contacts 1518 may be soldered or welded together. In other examples, the electrode connectors 1504a, 1504b, 1504c, 1504d may be connected to the PCB 220 by a plug and socket arrangement.

[0365] On the opposite side of the front-end feedthrough 224, the electrode connectors 1504a, 1504b, 1504c, 1504d are connected to the electrode lead 104. In particular, each of the electrode connectors 1504a, 1504b, 1504c, 1504d is connected to one of the electrode wires 1512a, 1512b, 1512c, 1512d shown in FIG. 15C. The electrode connectors 1504a, 1504b, 1504c, 1504d can be connected to the electrode wires 1512a, 1512b, 1512c, 1512d by soldering, or by using ferrules. The connections between the electrode connectors 1504a, 1504b, 1504c, 1504d and the electrode lead 104 also helps to secure the electrode lead 104 to the housing portion 102.

[0366] The front-end feedthrough 224 also includes a lead antenna connector 1506 extending through the front-end feedthrough 224 in the same manner as the electrode connectors 1504a, 1504b, 1504c, 1504d. On the inside, the lead antenna connector 1506 is connected to the PCB 220, and on the opposite side the lead antenna connector 1506 is connected to the antenna wire 1514 via the lead connector 210.

[0367] As shown in FIG. 15B, the front-end feedthrough 224 also includes a metallic insert 1516. The metallic insert 1516 is a metal, preferably platinum-iridium alloy or titanium. The metallic insert 1516 forms a part of the front-end feedthrough 224, in particular a segment of the front-end feedthrough 224. The metallic insert 1516 extends only partly through the thickness of the front-end feedthrough 224 in the axial direction. The metallic insert 1516 canbe brazed, or welded to the inside of the first weld ring 212 to secure the front-end feedthrough 224 within the first weld ring 212. Alternatively, the metallic insert 1516 can be formed by pouring molten metal into a recess in the front-end feedthrough 224 when the front-end feedthrough 224 is received in the first weld ring 212.

[0368] A connecting pin 1508 extends through the front-end feedthrough 224 at the metallic insert 1516. The connecting pin 1508 is attached to the electrode lead 104 and to the PCB 220 in the same manner as the electrode connectors 1504a, 1504b, 1504c, 1504d described above. The connecting pin 1508 may be used to improve mechanical connection between the electrode lead 104 and the front-end feedthrough 224, and between the front-end feedthrough 224 and the PCB 220.

[0369] The metallic insert 1516 electrically connects the first weld ring 212 to the PCB 220, see FIG. 2C) via the connecting pin 1508. This may be used to ground the first weld ring 212. Additionally or alternatively, the first weld ring 212 may act as an additional electrode of the medical implant 102. The first weld ring 212 may therefore be used for stimulation and / or sensing. As described above, during assembly the first weld ring 212 is joined to the second weld ring 214, so in some examples the combined first weld ring 212 and second weld ring 214 may provide an electrode.

[0370] Accordingly, the front-end feedthrough 224 provides a sealed end at the front-end 202 of the tubular housing 208 and electrical connections between the electrode lead 104 and the PCB 220 within the housing portion 102. The front-end feedthrough 224 may also provide an electrical connection between the first weld ring 212 and the PCB 220, which can provide an additional electrode for the medical implant 100.

[0371] In alternative examples, the front-end feedthrough 224 may comprise a metallic body, for example platinum-iridium. In this example, the electrode connectors 1504a, 1504b, 1504c, 1504d are electrically insulated from the front-end feedthrough 224, for example by insulative sleeves. In such examples, the front-end feedthrough 224 may be welded to the first weld ring 212, or directly to the second weld ring 214 on the tubular housing 208 (see FIG. 2A). In such examples the second weld ring 214 may be omitted and the front-end feedthrough 224 may be welded directly to the second weld ring 214 on the tubular housing 208.

[0372] In a final assembly step, shown in FIG. 16, the electrode lead 104 is attached by joining the lead connector 210 to the front-end feedthrough 224 and by joining the wires in the electrode lead 104 to the front-end feedthrough 224. Once the electrical connections have beenformed any space within the lead connector 210 can be filled with an epoxy to encase and seal the connections.

[0373] FIG. 17 illustrates an example delivery device 1702 for implanting the medical implant 100 in a patient. The delivery device 1702 is substantially as described in applicant's international PCT application PCT / EP2021 / 085998 (WO2022129234A1).

[0374] The delivery device 1702 includes a handle 1704 with a first needle 1706 and a second needle 1708 extending parallelly from the handle 1704. The first needle 1706 is larger than the second needle 1708, i.e., has a lumen with a larger internal diameter. The second needle 1708 extends further from the handle 1704 than the first needle 1706.

[0375] The housing portion 102 is held in a lumen of first needle 1706. The electrode lead 104 extends from the housing portion 102 and into the second needle 1708 and is held in a lumen of the second needle 1708. The second needle 1708 is retractable relative to the handle 1704. The second needle 1708 may be received in the lumen of the first needle 1706, or may extend alongside the first needle 1706.

[0376] During implantation, the second needle 1708 is inserted at a first depth in the patient's tissue to position the electrode lead 104 close to a nerve 116 (see FIG. IB). Simultaneously or subsequently, the first needle 1706 is inserted at a second, shallower, depth in the patients tissue to position the housing portion 102. The second needle 1708 is then retracted, for example by pulling pull tab 1720, to expose the electrode lead 104, in particular the electrodes 106a, 106b, 106c, 106d.

[0377] The position of the electrodes 106a, 106b, 106c, 106d relative to the nerve can be tested by powering the medical implant 100 before full implantation. As shown in FIG. 17, the delivery device 1702 includes a power supply 1710 that is connected to the medical implant 100 via a first contact 1716 and a second contact 1718 formed in the first needle 1706. In particular, the first contact 1716 and the second contact 1718 are in contact with a first electrode 1712 and second electrode 1714 on the housing portion 102 to provide power to the housing portion 102. The first electrode 1712 and the second electrode 1714 may be two of the electrodes 216a, 216b, 216c, 216d described with reference to FIG. 2A to FIG. 2C.

[0378] If testing determines that the position of the electrode lead 104 is not correct or not optimal, the second needle 1708 can be re-extended and the delivery device 1702 can repositioned . The above process can be repeated until the electrode lead 104 is appropriately positioned.

[0379] Once the electrode lead 104 and the housing portion 102 are appropriately positioned, the second needle 1708 can be fully retracted towards the handle 1704 and the delivery device 1702 can be removed from the patient leaving the electrode lead 104 and the housing portion 102 implanted. The housing portion 102 may be pushed out of the first needle 1706, for example using a pusher.

[0380] Accordingly, at least some, for example two, of the electrodes 216a, 216b, 216c, 216d on the housing portion 102 can be used to power the medical implant 100 during implantation.

[0381] Once the medical implant 100 has been implanted into the patient's tissue, at least some of the electrodes 216a, 216b, 216c, 216d on the housing portion 102 can be used to sense one or more physiological parameters of the patient, for example physiological parameters or vital signs of the patient. In particular, the electrodes 216a, 216b, 216c, 216d may be used to detect one or more of body temperature, heart rate, electromyography (EMG), electrocardiogram (ECG), respiration rate, blood pressure, and / or blood gas concentration (e.g., oxygen (oxygen saturation), carbon dioxide, carbon monoxide).

[0382] FIG. 18 to FIG. 20 illustrate example housing portions 2702, 800, 900 for a medical implant, for example a neurostimulator or diagnostic implant. The housing portion 2702 of FIG. 18 may be similar or identical to the housing portion 102 of FIG. 1A, and may be suitable for the medical implant 100 described above.

[0383] The housing portion 2702 comprises a ceramic tubular housing 2704 for housing an electronics assembly (not shown), such as the electronics assembly 502 described above. The ceramic tubular housing 2704 may be similar or the same as the tubular housing 208 of FIG.1A. For example, the ceramic tubular housing 2704 may have any combination of features discussed in relation to the tubular housing 208.

[0384] The housing portion 2702 further comprises a metallic connecting ring 2714 such as a weld ring. The metallic connecting ring 2714 may be similar or the same as the second weld ring 214. For example, the metallic connecting ring 2714 may have any combination of features discussed in relation to the second weld ring 214.

[0385] As shown in FIG. 18, the ceramic tubular housing 2704 includes a first end 2706 having a first mating face 2710. The metallic connecting ring 2714 includes a second end 2716 having a second mating face 2720. The first end 2706 may be a front end of the ceramic tubular housing 2704 while the second end 2716 may be a rear end of the metallic connecting ring2714. In this example, a front end of the metallic connecting ring 2714 is configured to receive an end cap such as the front-end feedthrough 224.

[0386] The first mating face 2710 of the ceramic tubular housing 2704 is joined to the second mating face 2720 of the metallic connecting ring 2714. In this example, the second mating face 2720 is brazed to the first mating face 2710 to form a flush joint 2724 between the metallic connecting ring 2714 and the ceramic tubular housing 2704. The first and second ends 2706, 2716 form a level external surface 2726 of the housing portion 2702.

[0387] Compared with a stepped or uneven joint, the level external surface 2726 of the housing portion 2702 may reduce tissue damage associated with movement of the medical implant e.g., during insertion.

[0388] In this example, the first end 2706 of the ceramic tubular housing 2704 and the second end 2716 of the metallic connecting ring 2714 also form a level internal surface 724 of the housing portion 2702.

[0389] The first end 2706 comprises a first recess 2708 which defines at least part of a first mating face 2710. The first recess 2708 forms a stepped end profile. The second end 2716 of the metallic connecting ring 2714 comprises a second recess 2718 defining at least part of the second mating face 2720. The second end 2716 may have a stepped profile. As shown in FIG. 18, the first recess 2708 extends around a circumference of the first end 2706 to form a first overhang portion 2712. As shown, the first overhang portion 2712 has an external diameter less than an external diameter of a remainder of the first end 2706.

[0390] The second recess 2718 extends around a circumference of the second end 2716 of the metallic connecting ring 2714 to form a second overhang portion 2722. The second overhang portion 1 2. has an internal diameter that is greater than an internal diameter of a remainder of the second end 2716. When assembled, the first overhang portion 2712 overlaps the second overhang portion 1 2. and the first mating face 2710 is parallel to, and overlapping, the second mating face 2720. Brazing material 2730 is disposed between the overlapping portions of the first and second overhang portions 2712, 21 2 to join the metallic connecting ring 2714 to the ceramic tubular housing 2704. The brazing material 2730 preferably comprises gold.

[0391] In this example, the ceramic tubular housing 2704 consists of a ceramic material such as zirconia. The metallic connecting ring 2714 is metallic, comprising a metal such as a platinum-iridium alloy or titanium. Creating a hermetic seal between dissimilar materials can be challenging. The first and second overhang portions 2712, 1 1 provide a greateroverlapping surface area for creating a hermetic seal therebetween than that provided by abutting end surfaces. The first and second overhang portion 2712, 21 2 are sized to ensure sufficient overlapping surface area for creating a hermetic seal therebetween. The first overhang portion 2712 may be configured to overlap with fixed length of the second overhang portion 1 2 around its circumference. For example, the fixed length may be greater than or equal to: 0.1mm; 0.25 mm; or 0.5 mm. In a preferred example, the fixed length may be greater than 1mm.

[0392] In an alternate arrangement (not shown), the mating faces 2710, 2720 may be swapped between the metallic connecting ring 2714 and the ceramic tubular housing 2704 such that the metallic connecting ring 2714 has a stepped end over which an overhang portion of the front end of the ceramic tubular housing 2704 is received.

[0393] In the example shown in FIG. 18, the first and second overhang portions 2712, 1 1 each terminate in respective flat end surface. In some examples, the first overhang portion 2712 may terminate in a contoured face. For example, the first overhang portion 2712 may have an undulating profile. Alternately, a terminal face of the first overhang portion 2712 may be stepped so that the first overhang portion 2712 has a toothed profile. The second overhang portion 1 2 has a correspondingly shaped profile to engage the first overhang portion 2712.

[0394] The housing portion 2702 may further comprise an end cap (not shown) such as the front-end feedthrough 224 or the end cap 218 coupled to the front end of the metallic connecting ring 2714 (opposite the second end 2716). The end cap may hermetically seal the first end of the housing portion 2702. The end cap may be termed a first end cap and the housing portion 2702 may comprise a second end cap such as a front-end feedthrough 224 or end cap 218. The metallic connecting ring 2714 may be termed the first metallic connecting ring 2714 and the flush joint 2724 termed the first flush joint 2724. The first end 2706 of the ceramic tubular housing 2704 may be the front end of the ceramic tubular housing 2704. The housing portion 2702 may include a second metallic connecting ring (not shown) configured to be brazed to a rear end of the ceramic tubular housing 2704. For example, the second metallic connecting ring may be the same as the first metallic connecting ring 2714 (rotated by 180°). Alternately, the second metallic connecting ring may be the same or substantially similar to the metallic connecting ring 2810 or the metallic connecting ring 2910 as described later in relation to FIG. 19 and FIG. 20.

[0395] The second metallic connecting ring may be brazed to the rear end of the ceramic tubular housing 2704 to form a second flush joint between the second connecting ring and the ceramic tubular housing 2704. A front end of the second metallic connecting ring and the rear end of the ceramic tubular housing 2704 may form a second level external surface of the housing portion 2702.

[0396] The second end cap may be coupled to a rear end of the second metallic connecting ring to seal the rear end of the housing portion 2702. The second end cap may or may not comprise an electronics assembly (e.g., the electronics assembly 502).

[0397] Either or both the first end cap or the second end cap may constitute a feedthrough, e.g., a front-end feedthrough 224, as described herein.

[0398] For example, a front end of the ceramic tubular housing may be brazed to the first end cap, such as a front-end feedthrough 224, while a rear end of the ceramic tubular housing is brazed to the second end cap such as end cap 218. Together, the first end cap and the second end cap may hermetically seal the electronics assembly within the housing portion 2702.

[0399] FIG. 19 shows another example housing portion 800 for a medical implant such as a neurostimulator or diagnostic implant. The housing portion 2800 of FIG. 19 comprises a ceramic tubular housing 2808, for housing an electronics assembly (not shown), having a first end 2801. The housing portion 2800 further includes a metallic connecting ring 2810, such as a weld ring. The metallic connecting ring 2810 has a second end 2811. The ceramic tubular housing 2808 may be the same as the ceramic tubular housing 2704 of FIG. 18, varying only by the configuration of the first end 2801. Similarly, the metallic connecting ring 2810 may be the same as the metallic connecting ring 2714 of FIG. 18, varying only by the configuration of the second end 2811.

[0400] As shown in FIG. 19, the first end 2801 of the ceramic tubular housing 2808 includes a first mating face 2803. The second end 2811 of the metallic connecting ring 2810 includes a second mating face 2813. The first end 2801 may be a front end of the ceramic tubular housing 2808 while the second end 2811 may be a rear end of the metallic connecting ring 2810. A front end of the metallic connecting ring 2810 may be configured to receive an end cap such as front-end feedthrough 224.

[0401] In this example, the first end 2801 comprises a first recess 2802. The first recess 2802 extends around a circumference of the first end 2801 of the ceramic tubular housing 2808 to form a first overhang portion 2805. As shown, the first overhang portion 2805 has an externaldiameter less than an external diameter of a remainder of the first end 2801. A terminal face of the first overhang portion 2805 defines a first mating face 2803 of the ceramic tubular housing 2808.

[0402] The second end 2811 of the metallic connecting ring 2810 comprises a second recess 2812. The second overhang portion 2815 has an external diameter less than an external diameter of a remainder of the second end 2811. A terminal face of the second overhang portion 2815 defines a second mating face 2813 of the metallic connecting ring 2810. The first mating face 2803 of the ceramic tubular housing 2808 is joined to the second mating face 2813 of the metallic connecting ring 2810 such that terminal faces of the first and second overhang portions 2805, 2815 abut. The first and second recesses 2802, 2812 connect to form a continuous circumferential groove in the housing profile.

[0403] As shown in FIG. 19, in this example the circumferential groove 2840 is defined by a rectangular cross-sectional profile. In alternate examples, the first and second recesses 2802, 2812 may be configured such that the circumferential groove 2840 is defined by any regular or irregular shaped profile. For example, the circumferential groove 2840 may have rounded edges and / or be defined by a hemispherical cross-sectional profile. In the example shown in FIG. 19, the cross-sectional profile is constant at each position around the circumferential groove 2840. However, the circumferential groove 2840 may instead have a cross-sectional profile which varies around the circumference of the housing portion 2800.

[0404] The second mating face 2813 is brazed to the first mating face 2803 to form a flush joint 2820 between the metallic connecting ring 2810 and the ceramic tubular housing 2808.

[0405] Brazing material 2830 fills the circumferential groove formed by the first recess 2802 and the second recess 2812, joining the metallic connecting ring 2810 to the ceramic tubular housing 2808. Preferably, the brazing material 2830 comprises gold. The first end 2801 of the ceramic tubular housing 2808, the second end 2811 of the metallic connecting ring 2810, and the brazing material 2830 form a level external surface 2822 of the housing portion 2800. Compared with a stepped or uneven joint, the level external surface 2822 of the housing portion 2800 may reduce tissue damage associated with movement of the medical implant e.g., during insertion.

[0406] Interior surfaces of the first overhang portion 2805 and the second overhang portion 2815 are contiguous along the flush joint 2820 so that the first end 2801 and the second end 2811 form a level internal surface 2824 of the housing portion 2800.

[0407] The housing portion 2800 may further comprise an end cap (not shown) such as the front-end feedthrough 224 or the end cap 218 coupled to the front end of the metallic connecting ring 2810 (opposite the second end 2811). The end cap may hermetically seal the first end of the housing portion 2800.

[0408] The end cap may be termed a first end cap and the housing portion 2800 may comprise a second end cap such as a front-end feedthrough 224 or end cap 218. The metallic connecting ring 2810 may be termed the first metallic connecting ring 2810 and the flush joint 2820 termed the first flush joint 2820. The first end 2801 of the ceramic tubular housing 2808 may be a front end of the ceramic tubular housing 2808. The housing portion 2800 may include a second metallic connecting ring (not shown) configured to couple to a rear end of the ceramic tubular housing 2808. For example, the second metallic connecting ring may be the same as the first metallic connecting ring 2810 (rotated by 180°). Alternately, the second metallic connecting ring may be substantially similar to the metallic connecting ring 2714 or the metallic connecting ring 2910 which is later described in relation to FIG. 20.

[0409] The second metallic connecting ring may be brazed to the rear end of the ceramic tubular housing 2808 to form a second flush joint between the second connecting ring and the ceramic tubular housing 2808. A front end of the second metallic connecting ring and the rear end of the ceramic tubular housing 2808 may form a second level external surface of the housing portion 2800.

[0410] The second end cap may be coupled to a rear end of the second metallic connecting ring to seal the rear end of the housing portion 2800. The second end cap may or may not comprise an electronics assembly (e.g., the electronics assembly 502).

[0411] Either or both the first end cap or the second end cap may constitute a feedthrough, e.g., a front-end feedthrough 224, as described herein.

[0412] For example, the front end of the ceramic tubular housing 2808 may be brazed to the first end cap, such as a front-end feedthrough 224, while a rear end of the ceramic tubular housing 2808 may be brazed to the second end cap (such as end cap 218). Together, the first end cap and the second end cap may hermetically seal the electronics assembly within the housing portion 2800.

[0413] FIG. 20 shows a further example housing portion 2900 for a medical implant such as a neurostimulator or diagnostic implant. The housing portion 900 of FIG. 20 comprises a ceramic tubular housing 2908, for housing an electronics assembly (not shown), having a firstend 2901. The housing portion 2900 further includes a metallic connecting ring 2910, such as a weld ring. The metallic connecting ring 2910 has a second end 2911. The ceramic tubular housing 2908 may be the same as the ceramic tubular housing 2704 of FIG. 18, varying only by the configuration of the first end 2901. Similarly, the metallic connecting ring 2910 may be the same as the metallic connecting ring 2714 of FIG. 18, varying only by the configuration of the second end 2911.

[0414] As shown in FIG. 20, the first end 2901 of the ceramic tubular housing 2908 includes a first mating face 2903. The second end 2911 of the metallic connecting ring 2910 includes a second mating face 2913. The first end 2901 may be a front end of the ceramic tubular housing 2908 while the second end 2911 may be a rear end of the metallic connecting ring 2910. A front end of the metallic connecting ring 2910 may be configured to receive an end cap such as front-end feedthrough 224.

[0415] In this example, the first end 2901 comprises a first bevelled edge 2902 which forms a first overhang portion 2905. The first bevelled edge 2902 defines forms part of the first mating face 2903 of the ceramic tubular housing 2908. The first bevelled edge 2902 is at a first angle 2904 to a longitudinal axis 2940 of the housing portion 2900. The first angle may be between 125° and 145° for example the first angle 2904 may be 135°.

[0416] The second end 2911 comprises a second bevelled edge 2912 which forms a second overhang portion 2915. The second bevelled edge 2912 is shaped correspondingly to the first bevelled edge 2902 and forms part of the second mating face 2913 of the metallic connecting ring 2910. The second bevelled edge 2912 is at a second angle 2914 to the longitudinal axis 2940. The second angle 2914 may be between 35° and 55°. For example, the second angle 2914 may be 45°. The first and second angles 2904, 2914 are supplementary, (i.e., they add to 180°). This configuration may ensure a close fit between the first bevelled edge 2902 and the second bevelled edge 2912 when the housing portion 2900 is assembled.

[0417] During assembly of the housing portion 2900, the first end 2901 of the ceramic tubular housing 2908 is positioned over the second end 2911 of the metallic connecting ring 2910. The second overhang portion 2915 overlaps and surrounds the first overhang portion 2905.

[0418] The first and second angles 2904, 2914 enable the metallic connecting ring 2910 and ceramic tubular housing 2908 to be assembled by translating the metallic connecting ring 2910 along the longitudinal axis 2940 towards the ceramic tubular housing 2908.

[0419] The first and second bevelled edge 2902, 2912 are configured to axially align the metallic connecting ring 2910 and the ceramic tubular housing 2908 when these components are assembled. Compressing the metallic connecting ring 2910 and the ceramic tubular housing 2908 together slides the first bevelled edge 2902 against the second bevelled edge 2912 to centre the metallic connecting ring 2910 and the ceramic tubular housing 2908. The first end 2901 of the metallic connecting ring 2910 is then brazed to the second end 2911 of the ceramic tubular housing 2908 to form a flush joint 2920. Brazing material 2930 disposed between the first and second bevelled edges 2902, 912 joins the metallic connecting ring 2910 to the ceramic tubular housing 2908.

[0420] In this example, the first overhang portion 2905 terminates in a flat rim 2906. The second mating face 2913 comprises a shoulder 2917 on which the flat rim 2906 rests. In this example, the flat rim 2906 has a width equal to a width of the shoulder 2917. In other examples, the flat rim 2906 may have any width less than or equal to the width of the shoulder 2917. In yet further examples, the first overhang portion 2905 may terminate at a rounded or sharp rim and the shoulder 2917 may be omitted.

[0421] As shown in FIG. 20, the brazing material 2930 fills a gap between the rounded rim 2916 of the second end 2911 and the first bevelled edge 2902. The first and second ends 2901, 2911 and brazing material 2930 form a level external surface 2922 of the housing portion 2900. Compared with a stepped or uneven joint, the level external surface 2922 of the housing portion 2900 may reduce tissue damage associated with movement of the medical implant e.g., during insertion.

[0422] Interior surfaces of the first end 2901 and the second end 2911 are contiguous along the flush joint 2920 so that the first and second ends 2901, 911 form a level internal surface 2924 of the housing portion 2900.

[0423] In this example, the first bevelled edge 2902 forms an outer facing surface of the ceramic tubular housing 2908 while the second bevelled edge 2912 forms an inner facing surface of the metallic connecting ring 2910. However, in other examples the first bevelled edge 2902 may form an inner facing surface of the ceramic tubular housing 2908 while the second bevelled edge 2912 forms an outer facing surface of the metallic connecting ring 2910 (i.e., the first overhang portion 905 may overlap and surround the second overhang portion 2915).

[0424] The housing portion 2900 may further comprise an end cap (not shown) such as the front-end feedthrough 224 or the end cap 218 coupled to the front end of the metallic connecting ring 2910 (opposite the second end 2911). The end cap may hermetically seal the first end of the housing portion 2900.

[0425] The end cap may be termed a first end cap and the housing portion 2900 may comprise a second end cap such as a front-end feedthrough 224 or end cap 218. The metallic connecting ring 2910 may be termed the first metallic connecting ring 2910 and the flush joint 2920 termed the first flush joint 2920. The first end 2901 of the ceramic tubular housing 2908 may be a front end of the ceramic tubular housing 2908. The housing portion 2900 may include a second metallic connecting ring (not shown) configured to be brazed to a rear end of the ceramic tubular housing 2908. For example, the second metallic connecting ring may be the same as the first metallic connecting ring 2910 (rotated by 180°). Alternately, the second metallic connecting ring may be substantially similar to the metallic connecting ring 2714 or the metallic connecting ring 2810 described previously in relation to FIG. 18 and FIG. 19 respectively.

[0426] The second metallic connecting ring may be brazed to the rear end of the ceramic tubular housing 2908 to form a second flush joint between the second metallic connecting ring and the ceramic tubular housing 2908. A front end of the second metallic connecting ring and the rear end of the ceramic tubular housing 2908 may form a second level external surface of the housing portion 2900.

[0427] The second end cap may be coupled to a rear end of the second metallic connecting ring to seal the rear end of the housing portion 2900. The second end cap may or may not comprise an electronics assembly (e.g., the electronics assembly 502).

[0428] Either or both the first end cap or the second end cap may constitute a feedthrough, e.g., a front-end feedthrough, as described herein.

[0429] For example, a front end of the ceramic tubular housing 2908 may be brazed to a first end cap, such as a front-end feedthrough 224, while a rear end of the ceramic tubular housing 2908 may be brazed to a second end cap (such as end cap 218). Together, the first end cap and the second end cap may hermetically seal the electronics assembly within the housing portion 2900.

[0430] FIG. 21 A and FIG. 2 IB show a further example housing portion 3000 for a medical implant such as a neurostimulator or diagnostic implant. As shown in FIG. 21 A, the housingportion 3000 comprises a ceramic tubular housing 3008, for housing an electronics assembly (not shown), having a first end 3001. The housing portion 3000 further includes a metallic connecting ring 3010, such as a weld ring. The metallic connecting ring 3010 has a second end 3011. The ceramic tubular housing 3008 may be the same as the ceramic tubular housing 2704 of FIG. 18, varying only by the configuration of the first end 3001. Similarly, the metallic connecting ring 3010 may be the same as the metallic connecting ring 2714 of FIG. 18, varying only by the configuration of the second end 3011.

[0431] As shown in FIG. 21A, the first end 3001 of the ceramic tubular housing 3008 includes a first mating face 3003. The second end 3011 of the metallic connecting ring 3010 includes a second mating face 3013. The first end 3001 may be a front end of the ceramic tubular housing 3008 while the second end 3011 may be a rear end of the metallic connecting ring 3010. A front end of the metallic connecting ring 3010 may be configured to receive an end cap such as front-end feedthrough 224.

[0432] In this example, the first end 3001 comprises a first set of teeth 3005 and a first set of sockets 3007 which together define the first mating face 3003. The second end 3011 may comprise a second set of teeth 3019 and a second set of sockets 3017 which together define the second mating face 3013. The first set of teeth 3005 project towards metallic connecting ring 3010 while the second set of teeth 3019 project towards the ceramic tubular housing 3008. The second set of sockets 3017 is configured to accommodate the first set of teeth 3005. Similarly, the first set of sockets 3007 is configured to accommodate the second set of teeth 3019.

[0433] In this example, the first set of teeth 3005 and the second set of teeth each comprise two teeth members (only one teeth member of the first set of teeth 3005 can be seen in FIG. 21A). The first set of teeth 3005 may comprise any number of teeth members e.g., 1, 2, 3, 4, 5 or more teeth members. Similarly, the second set of teeth 3019 may comprise any number of teeth members e.g., 1, 2, 3, 4, 5 or more teeth members.

[0434] As shown in FIG. 21A, the first set of teeth 3005 may be evenly spaced around the circumference of the first end 3001. Similarly, the second set of teeth 3019 may be evenly spaced around the second end 3011. The housing portion 3000 may be configured such that when the metallic connecting ring 3010 is coupled to the ceramic tubular housing 3008, the first set of teeth 3005 and the second set of teeth 3019 interlock.

[0435] FIG. 21 B shows the housing portion 3000 of FIG. 21 A, after the metallic connecting ring 3010 has been brazed to the ceramic tubular housing 3008.

[0436] As shown, the second mating face 3013 is brazed to the first mating face 3003 to form a flush joint 3020 between the metallic connecting ring 3010 and the ceramic tubular housing 3008.

[0437] In this example, each of the first set of teeth 3005 comprise a curved outer surface with an external radius equal to the external radius of the remainder of the ceramic tubular housing 3008. Each of the second set of teeth 3019 comprise a curved outer surface with an external radius equal to the external radius of the remainder of the metallic connecting ring 3010.

[0438] Brazing material 3030 is disposed between the first mating face 3003 and the second mating face 3013. Together, the first set of teeth 3005, the second set of teeth 3019 and the brazing material 3030 define a level external surface 3022 of the housing portion 3000. Compared with a stepped or uneven joint, the level external surface 3022 of the housing portion 3000 may reduce tissue damage associated with movement of the medical implant e.g., during insertion.

[0439] Interior surfaces of the first set of teeth 3005 and the second set of teeth 3019 are aligned along the flush joint 3020 so that the first end 3001 and the second end 3011 form a level internal surface (not shown) of the housing portion 3000.

[0440] The housing portion 3000 may further comprise an end cap (not shown) such as the front-end feedthrough 224 or the end cap 218 coupled to the front end of the metallic connecting ring 3010 (opposite the second end 3011). The end cap may hermetically seal the first end of the housing portion 3000.

[0441] The end cap may be termed a first end cap and the housing portion 3000 may comprise a second end cap such as a front-end feedthrough 224 or end cap 218. The metallic connecting ring 3010 may be termed the first metallic connecting ring 3010 and the flush joint 3020 termed the first flush joint 3020. The first end 3001 of the ceramic tubular housing 3008 may be a front end of the ceramic tubular housing 3008. The housing portion 102 may include a second metallic connecting ring (not shown) configured to couple to a rear end of the ceramic tubular housing 3008. For example, the second metallic connecting ring may be the same as the first metallic connecting ring 3010 (rotated by 180°). Alternately, the second metallic connecting ring may be substantially similar to the metallic connecting ring 2714, metallic connecting ring 2810, metallic connecting ring 2910 or the metallic connecting ring 3110 which is later described in relation to FIG. 22.

[0442] The second metallic connecting ring may be brazed to the rear end of the ceramic tubular housing 3008 to form a second flush joint between the second connecting ring and the ceramic tubular housing 3008. A front end of the second metallic connecting ring and the rear end of the ceramic tubular housing 3008 may form a second level external surface of the housing portion 3000.

[0443] The second end cap may be coupled to a rear end of the second metallic connecting ring to seal the rear end of the housing portion 3000. The second end cap may or may not comprise an electronics assembly (e.g., the electronics assembly 502).

[0444] Either or both the first end cap or the second end cap may constitute a feedthrough, e.g., a front-end feedthrough 224, as described herein.

[0445] For example, the front end of the ceramic tubular housing 3008 may be brazed to the first end cap, such as a front-end feedthrough 224, while a rear end of the ceramic tubular housing 3008 may be brazed to the second end cap (such as end cap 218). Together, the first end cap and the second end cap may hermetically seal the electronics assembly within the housing portion 3000.

[0446] FIG. 22 shows a further example housing portion 3100 for a medical implant such as a neurostimulator or diagnostic implant. As shown in FIG. 22, the housing portion 3100 comprises a ceramic tubular housing 3108, for housing an electronics assembly (not shown), having a first end 3101. The housing portion 3100 further includes a metallic connecting ring 3110, such as a weld ring. The metallic connecting ring 3110 has a second end 3111. The ceramic tubular housing 3108 may be the same as the ceramic tubular housing 2704 of FIG. 18, varying only by the configuration of the first end 3101. Similarly, the metallic connecting ring 3110 may be the same as the metallic connecting ring 2714 of FIG. 18, varying only by the configuration of the second end 3111.

[0447] As shown in FIG. 22, the first end 3101 of the ceramic tubular housing 3108 includes a first mating face 3103. The second end 3111 of the metallic connecting ring 3110 includes a second mating face 3113. The first end 3101 may be a front end of the ceramic tubular housing 3108 while the second end 3111 may be a rear end of the metallic connecting ring 3110. A front end of the metallic connecting ring 3110 may be configured to receive an end cap such as front-end feedthrough 224.

[0448] In this example, the first end 3101 terminates in a first flat rim 3106 which defines the first mating face 3103. The first mating face 3103 is oriented parallel to the radius of theceramic tubular housing 3108. Similarly, the second end 3111 terminates in a second flat rim 3116 which defines the second mating face 3113. The second mating face 3113 is oriented parallel to the radius of the metallic connecting ring 3110. When the metallic connecting ring3110 is brazed to the ceramic tubular housing 3108, the first flat rim 3106 is parallel to the second flat rim 3116.

[0449] As shown, the second mating face 3113 is brazed to the first mating face 3103 to form a flush joint 3120 between the metallic connecting ring 3110 and the ceramic tubular housing 3108. Brazing material 3130 is disposed between the first mating face 3103 and the second mating face 3113. Together, the first end 3101, the second end 3111 and the brazing material 3130 define a level external surface 3122 of the housing portion 3100. Compared with a stepped or uneven joint, the level external surface 3122 of the housing portion 3100 may reduce tissue damage associated with movement of the medical implant e.g., during insertion.

[0450] An interior surface 3123 of the brazing material 3130 is contiguous with interior surfaces of both the metallic connecting ring 3110 and the ceramic tubular housing 3108, along the flush joint 3120. As such, the first end 3101, the brazing material 3130 and the second end3111 form a level internal surface 3124 of the housing portion 3100.

[0451] The housing portion 3100 may further comprise an end cap (not shown) such as the front-end feedthrough 224 or the end cap 218 coupled to the front end of the metallic connecting ring 3110 (opposite the second end 3111). The end cap may hermetically seal the first end of the housing portion 3100.

[0452] The end cap may be termed a first end cap and the housing portion 3100 may comprise a second end cap such as a front-end feedthrough 224 or end cap 218. The metallic connecting ring 3110 may be termed the first metallic connecting ring 3110 and the flush j oint 3120 termed the first flush joint 3120. The first end 3101 of the ceramic tubular housing 3108 may be a front end of the ceramic tubular housing 3108. The housing portion 3100 may include a second metallic connecting ring (not shown) configured to couple to a rear end of the ceramic tubular housing 3108. For example, the second metallic connecting ring may be the same as the first metallic connecting ring 3110 (rotated by 180°). Alternately, the second metallic connecting ring may be substantially similar to the metallic connecting ring 2714, metallic connecting ring 2810, metallic connecting ring 2910 or the metallic connecting ring 3010.

[0453] The second metallic connecting ring may be brazed to the rear end of the ceramic tubular housing 3108 to form a second flush joint between the second connecting ring and theceramic tubular housing 3108. A front end of the second metallic connecting ring and the rear end of the ceramic tubular housing 3108 may form a second level external surface of the housing portion 3100.

[0454] The second end cap may be coupled to a rear end of the second metallic connecting ring to seal the rear end of the housing portion 3100. The second end cap may or may not comprise an electronics assembly (e.g., the electronics assembly 502).

[0455] Either or both the first end cap or the second end cap may constitute a feedthrough, e.g., a front-end feedthrough 224, as described herein.

[0456] For example, the front end of the ceramic tubular housing 3108 may be brazed to the first end cap, such as a front-end feedthrough 224, while a rear end of the ceramic tubular housing 3108 may be brazed to the second end cap (such as end cap 218). Together, the first end cap and the second end cap may hermetically seal the electronics assembly within the housing portion 3100.

[0457] FIG. 23 and FIG. 24 show further example housing portions 2302, 2402 for a medical implant such as a neurostimulator or diagnostic implant.

[0458] As shown in FIG. 23, the housing portion 2302 comprises a ceramic tubular housing 2304, for housing an electronics assembly (not shown). The housing portion 2302 further includes a metallic connecting ring 2306, such as a first weld ring. The metallic connecting ring 2306 has a first end that is brazed to the ceramic tubular housing 2304 at braze joint 2316. In this example, the end of the ceramic tubular housing 2304 and the end of the metallic connecting ring 2306 that are brazed together are both straight, flush edges. The braze joint 2316 may comprise gold or active brazing alloys (ABA).

[0459] As illustrated, the other end of the metallic connecting ring 2306 is attached to a second metallic connecting ring, in particular a second weld ring 2308. In this example, the second weld ring 2308 comprises a stepped inner end configured to receive the end of the metallic connecting ring 2306 in order to align the metallic connecting ring 2306 and the second weld ring 2308. The metallic connecting ring 2306 and the second weld ring 2308 are welded to each other at weld 2314.

[0460] A feedthrough 2310 is attached within the second weld ring 2308. The feedthrough 2310 comprises a ceramic body that is brazed to the inner surface of the second weld ring 2308, for example using gold or ABA. The feedthrough 2310 comprises one or more connectors, pins or conductors 2312 passing therethrough to provide an electrical connection across thefeedthrough 2310, in particular between an electronics assembly housed within the ceramic tubular housing 2304 and an electrode lead connected at the end, as described previously.

[0461] When assembling the housing portion 2302 of FIG. 23 the metallic connecting ring 2306 is first brazed to the end of the ceramic tubular housing 2304 at the braze joint 2316. This is beneficially performed before assembling the electronics assembly into the ceramic tubular housing 2304. The feedthrough 2310 is brazed into the second weld ring 2308. The second weld ring 2308, with the feedthrough 2310, is then welded onto the metallic connecting ring 2306 at weld 2314. Weld 2314 may be formed before or after assembling the electronics assembly into the ceramic tubular housing 2304. The braze joint 2316 and weld 2314 provide a hermetic seal.

[0462] The example housing portion 2402 of FIG. 24 is similar to the housing portion 2302 of FIG. 23. In particular, as shown in FIG. 24, the housing portion 2402 comprises a ceramic tubular housing 2404, for housing an electronics assembly (not shown). The housing portion 2402 further includes a metallic connecting ring 2406, such as a first weld ring. The metallic connecting ring 2406 has a first end that is brazed to the ceramic tubular housing 2404 at braze joint 2416. In this example, the end of the ceramic tubular housing 2404 and the end of the metallic connecting ring 2406 that are brazed together are both straight, flush edges. The braze joint 2416 may comprise gold or active brazing alloys (ABA).

[0463] As illustrated, the other end of the metallic connecting ring 2406 is attached to a second metallic connecting ring, in particular a second weld ring 2408. In this example, the ends of the metallic connecting ring 2406 and the second weld ring 2408 are straight, flush edges that are welded together. The metallic connecting ring 2406 and the second weld ring 2408 are welded to each other at weld 2414.

[0464] A feedthrough 2410 is attached within the second weld ring 2408. The feedthrough 2410 comprises a ceramic body that is brazed to the inner surface of the second weld ring 2308, for example using gold or ABA. The feedthrough 2410 comprises one or more connectors, pins or conductors 2412 passing therethrough to provide an electrical connection across the feedthrough 2410, in particular between an electronics assembly housed within the ceramic tubular housing 2404 and an electrode lead connected at the end, as described previously.

[0465] The housing portion 2402 of FIG. 24 can be assembled in the same manner as the example of FIG. 23.

[0466] In both of the examples of FIG. 23 and FIG. 24 the braze joint 2316, 2416, which may be termed a face braze 2316, 2416, advantageously joins the ceramic tubular housing 2304, 2404 to the metallic connecting ring 2306, 2406 in such a way that it does not increase the size of the outer diameter or reduce the size of the inner diameter.

[0467] FIG. 25 illustrates a method 3200 of assembling a housing portion for a medical implant for example a neurostimulator or diagnostic implant.

[0468] A first step 3201 of the method 3200 involves providing a ceramic tubular housing for housing an electronics assembly, the ceramic tubular housing having a first end with a first mating face.

[0469] A second step 3202 of the method 3200 involves providing a metallic connecting ring having a second end with a second mating face. This step may include assembling the metallic connecting ring and the ceramic tubular housing and applying an axial compressive force to the metallic connecting ring and the ceramic tubular housing to axially align the metallic connecting ring with the ceramic tubular housing. Compressing the metallic connecting ring and the ceramic tubular housing together may slide the first bevelled edge against the second bevelled edge to centre the metallic connecting ring and the ceramic tubular housing.

[0470] A third step 3203 of the method 3200 involves brazing the second mating face to the first mating face to form a flush joint between the metallic connecting ring and the ceramic tubular housing. The first end of the ceramic tubular housing and second end of the metallic connecting ring form a level external surface of the housing portion.

[0471] A fourth step 3204 of the method 3200 involves providing an end cap, comprising an electronics assembly, for sealing the first end of the ceramic tubular housing. The electronics assembly may be fixedly or reversibly fixed to the end cap. In some examples, the electronics assembly may comprise a PCB.

[0472] The medical implant may comprise an electrode lead. The end cap may provide electrical connection between the electrode lead and the PCB within the ceramic tubular housing. For example, the end cap may comprise a feedthrough such as front-end feedthrough 224 of FIG. 7A .

[0473] A fifth step 3205 may include inserting the electronics assembly into the ceramic tubular housing. This step may involve threading at least part of electronics assembly through the metallic connecting ring and into the ceramic tubular housing. After the fifth step 3205 iscompleted, a front end of the metallic connecting ring, opposite the second end, may contact a rear end of the end cap.

[0474] A sixth step 3206 may involve welding the end cap to the metallic connecting ring to form the housing portion. The rear end of the end cap may be welded to the front end of the metallic connecting ring e.g., by laser welding. This step may create a hermetic seal between the end cap and the metallic connecting ring.

[0475] The steps of the method 3200 may be performed in any suitable order. For example, the fifth and sixth steps 3205, 3206 of inserting the electronics assembly and welding the end cap to the metallic connecting ring may be performed after the third step 3203 of brazing the metallic connecting ring to the ceramic tubular housing. Beneficially, this order may allow a hermetic seal to be formed between the dissimilar materials of the ceramic tubular housing and the metallic connecting ring (by brazing) while preventing damage to the electronics caused by heating during the brazing process.

[0476] The second to sixth steps 3202-3206 of the method 3200 (second step 3202, third step 3203, fourth step 3204, fifth step 3205 and the sixth step 3206) may be repeated to provide a housing portion with two end caps e.g., an end cap provided at both ends of the ceramic tubular housing.

[0477] For example, the metallic connecting ring may be termed a first metallic connecting ring and the level external surface termed a first level external surface. The first end of the ceramic tubular housing may be termed the front end of the ceramic tubular housing. A rear end of the ceramic tubular housing may have a third mating face.

[0478] The method 3200 may include steps of: providing a second metallic connecting ring having a rear end with a fourth mating face; brazing the fourth mating face to the third mating face to form a flush joint between the second metallic connecting ring and the ceramic tubular housing such that the front end of the second metallic connecting ring and the rear end of the ceramic tubular housing form a second level external surface of the housing portion; providing a second end cap for sealing the rear end of the ceramic tubular housing and welding the second end cap to the second metallic connecting ring to seal the rear end of the ceramic tubular housing.

[0479] The method 3200 may be suitable for assembling the housing portion 102, 2702, 2800 or 2900 of FIGS. 7 to FIG. 20. For example, the ceramic tubular housing of the method 3200 may be any ceramic tubular housing discussed herein such as the tubular housing 208 or theceramic tubular housing 2704, 2808 or 2908. The (first and / or second) metallic connecting ring of the method 3200 may be the metallic connecting ring 2714, 2810, 2910 of FIG. 18 to FIG. 24. The (first and / or second) end cap may be the front-end feedthrough 224 or the end cap 218.

[0480] FIG. 26 illustrates an example delivery device 3402 for implanting the medical implant 100 in a patient. The delivery device 3402 is substantially as described in applicant's international PCT application PCT / EP2021 / 085998 (WO2022129234A1).

[0481] The delivery device 3402 includes a handle 3404 with a first needle 3406 and a second needle 3408 extending parallelly from the handle 3404. The first needle 3406 is larger than the second needle 3408, i.e., has a lumen with a larger internal diameter. The second needle 3408 extends further from the handle 3404 than the first needle 3406.

[0482] The housing portion 102 is held in a lumen of first needle 3406. The electrode lead 104 extends from the housing portion 102 and into the second needle 3408 and is held in a lumen of the second needle 3408. The second needle 3408 is retractable relative to the handle 3404. The second needle 3408 may be received in the lumen of the first needle 3406, or may extend alongside the first needle 3406.

[0483] During implantation, the second needle 3408 is inserted at a first depth in the patient's tissue to position the electrode lead 104 close to a nerve 116 (see FIG. IB). Simultaneously or subsequently, the first needle 3406 is inserted at a second, shallower, depth in the patients tissue to position the housing portion 102. The second needle 3408 is then retracted, for example by pulling pull tab 3420, to expose the electrode lead 104, in particular the electrodes 106a, 106b, 106c, 106d.

[0484] The position of the electrodes 106a, 106b, 106c, 106d relative to the nerve can be tested by powering the medical implant 100 before full implantation. As shown in FIG. 26, the delivery device 3402 includes a power supply 3410 that is connected to the medical implant 100 via a first contact 3416 and a second contact 3418 formed in the first needle 3406. In particular, the first contact 3416 and the second contact 3418 are in contact with a first electrode 3412 and second electrode 3414 on the housing portion 102 to provide power to the housing portion 102. The first electrode 3412 and the second electrode 3414 may be two of the electrodes 216a, 216b, 216c, 216d described with reference to FIG. 2A to FIG. 2C.

[0485] If testing determines that the position of the electrode lead 104 is not correct or not optimal, the second needle 3408 can be re-extended and the delivery device 3402 canrepositioned . The above process can be repeated until the electrode lead 104 is appropriately positioned.

[0486] Once the electrode lead 104 and the housing portion 102 are appropriately positioned, the second needle 3408 can be fully retracted towards the handle 3404 and the delivery device 3402 can be removed from the patient leaving the electrode lead 104 and the housing portion 102 implanted. The housing portion 102 may be pushed out of the first needle 3406, for example using a pusher.

[0487] Accordingly, at least some, for example two, of the electrodes 216a, 216b, 216c, 216d on the housing portion 102 can be used to power the medical implant 100 during implantation.

[0488] Once the medical implant 100 has been implanted into the patient's tissue, at least some of the electrodes 216a, 216b, 216c, 216d on the housing portion 102 can be used to sense one or more parameters of the patient, for example vital signs of the patient. In particular, the electrodes 216a, 216b, 216c, 216d may be used to detect one or more of body temperature, heart rate, electromyography (EMG), electrocardiogram (ECG), respiration rate, blood pressure, and / or blood gas concentration (e.g., oxygen, carbon dioxide, carbon monoxide).

[0489] FIG. 27A and FIG. 27B illustrate another example medical implant, in particular a housing assembly 4400 of a medical implant. In FIG. 27A the housing assembly 4400 is partially disassembled, and in FIG. 27B the housing assembly 4400 is assembled. In this example the housing assembly 4400 includes a battery. The battery may power the electronics assembly 4406 housed within the tubular housing 4402.

[0490] As illustrated, the housing assembly 4400 includes a battery housing cap 4414 that houses one or more battery cells 4420. The battery cells 4420 may be sealed within the battery housing cap 4414 by a sealing plate 4416 such that the battery housing cap 4414 and sealing plate 4416 form a battery casing. Terminals 4418 extend from the sealing plate 4416, or from the battery cells 4420 and through the sealing plate 44716. As shown, when the battery housing cap 44714 is attached to the tubular housing 4402, for example by a second weld ring 4412, the terminals 4418 connect to the electronics assembly 4406, for example on contacts. The opposite end of the tubular housing 4402 can be closed by an end cap 4404 that supports the electronics assembly 4406. The end cap 4404 can attach to a first weld ring 4410. However, in alternative examples the end cap 4404 may be a front-end feedthrough as described above.

[0491] In examples, the battery housing cap 4414 may be conductive, in particular metallic, and may be connected to the electronics assembly 4406 and act as a part (e.g., an arm) of an antenna, and / or as an electrode, for example a sensing electrode or a stimulating electrode.

[0492] As illustrated, the battery housing cap 4414 has an outer dimension, in this example an outer diameter, that matches the outer dimension of the tubular housing 4402. Accordingly, when the battery housing cap 4414 is attached to the tubular housing 4402 they form a flush outer surface.

[0493] Advantageously, housing the battery cells 4420 within a battery housing cap 4414 that forms a part of the housing assembly 4400 obviates the need for a separate battery housing that may add weight and / or size of the housing assembly 4400. Accordingly, the battery housing cap 4414 provides a convenient housing for a battery for a small medical implant.

[0494] FIG. 28 shows a medical implant 3500, comprising a housing assembly 3502. In this example, the medical implant 3500 is a neurostimulator which may be suitable for treating chronic pain. In other examples, the medical implant 3500 may be a diagnostic implant that monitors the health of a patient by detecting one or more parameters of the patient, such as heart rate or blood pressure or senses neural signals of the patient.

[0495] The housing assembly 3502 comprises a tubular housing 3504. In this example, the tubular housing 3504 is substantially cylindrical but it will be understood that the tubular housing 3504 may have any partially hollow shape (e.g., the tube have any regular or irregular shaped cross-section such as an octagonal cross-section or a oval shaped cross-section). An electronics assembly 3506 of the medical implant 3500 is received within the tubular housing 3504, as described further hereinafter.

[0496] As shown in FIG. 28, the medical implant 3500 comprises an electrode lead 3508 attached to the housing assembly 3502 via a lead connector 3524. The electrode lead 3508 has one or more lead wires 3510. In this example, the electrode lead 3508 comprises five lead wires 3510a, 3510b, 3510c, 3510d, 3510e. In other examples, the electrode lead 3508 may comprise two, three, four, six or more lead wires 3510.

[0497] The electrode lead 3508 is elongate and extends away from the housing assembly 3502. The electrode lead 3508 is flexible and comprises at least one electrode 3520 for neurostimulation. In this example, each of the five lead wires 3510a, 3510b, 3510c, 3510d, 3510e comprises a respective electrode 3520a, 3520b, 3520c, 3520d, 3520e. The electrodes 3520 are spaced along a length of the electrode lead 3508. The electrodes 3520 are positionedat an end of the electrode lead 3508 distal from the housing assembly 3502. The electrodes 3520 are connected to the electronics assembly 3506 within the tubular housing 3504 via the electrode lead 3508 and the lead connector 3524. In this example, the electrodes 3520 are metal, preferably a platinum-iridium alloy or titanium.

[0498] In examples, the electrodes 3520 are controlled by the electronics assembly 3506 housed in the tubular housing 3504 to provide electrical stimulation to stimulate a target nerve of the patient. In some examples where the medical implant is a diagnostic implant, the electrodes 3520 are operated by the electronics assembly 3506 housed in the housing assembly 3502, to sense or detect neural signals or other non-neural parameters of the patient (e.g., bioimpedance, differential bioimpedance, blood pressure, or heart rate). In examples, at least one of the electrodes 3520 may comprise different materials, in particular different metals, to another of the electrodes 3520 and may be operated to detect a differential bioimpedance. In examples, the electrodes 106a, 106b, 106c, 106d are operable in a first mode to detect neural signals, and operable in a second mode to stimulate the target nerve of the patient. In examples, some of the electrodes 3520 are operable to detect neural signals, while others of the electrodes 3520 are operable to stimulate the target nerve. In examples, some of the electrodes 3520 are operable to detect / stimulate the target nerve, and others are operable to sense other (non-neural) parameters.

[0499] In examples, the medical implant 3500 may be implantable to sense and / or stimulate the greater occipital nerve, the tibial nerve, the sacral nerve (e.g., to treat urinary incontinence), or the vagus nerve (e.g., to regulate pancreatic secretion). In other examples, the medical implant 3500 may be implantable to sense and / or stimulate the Hypoglossal nerve (including the distal branches within the genioglossus muscle) and / or the Phrenic nerve and / or the Ansa Cervicalis nerve, for example to detect and / or treat sleep apnea.

[0500] The electronics assembly 3506 of the medical implant 3500 may include a signal generator for generating signals for the electrodes 3520. In operation, the electrodes 3520 may be provided with an electrical signal, such as a current, to stimulate the nerve. The electrical signal may be a voltage-regulated stimulation. Such stimulation may provide relief for chronic pain, for example occipital neuralgia, intractable migraine, and / or other therapeutic benefits.

[0501] In examples, the medical implant 3500 is battery-less, i.e., it does not have an integrated power source. An external device (not shown) may wirelessly power the medical implant 3500. The external device may additionally wirelessly communicate with the medicalimplant 3500, in particular the electronics assembly 3506 within the tubular housing 3504. The medical implant 3500 may contain a wireless communications receiver / transmitter for communicating with the external device. The medical implant 3500 may also have a processor or controller configured to operate the medical implant 3500. The external device may be positioned on an external side of the patient's skin proximal to the medical implant 3500. The external device may be adhered to the skin in this position. The external device may be a wearable device. In other examples, the electronics assembly may comprise a battery for powering the medical implant 3500. Where present, the battery may be housed within the tubular housing 3504 and hermetically sealed therein.

[0502] In some examples where the medical implant 3500 is a diagnostic implant, for example a neurodiagnostic implant, the medical implant 3500 may be operable to detect one or more neural signals in a nerve. In such examples, the electrodes 3520 are operable to detect neural signals. The neural signals may be analysed for the purposes of detecting, monitoring and / or diagnosing a condition.

[0503] In other examples, the medical implant 3500 may be a diagnostic implant operable to detect one or more patient vital signs, for example bioimpedance, differential bioimpedance, body temperature, heart rate, electromyography (EMG), electrocardiogram (ECG), respiration rate, blood pressure, and / or blood gas concentration (e.g., oxygen, carbon dioxide, carbon monoxide). Detecting bioimpedance may allow the medical implant 3500 to detect certain other parameters relating to the tissue and fluid (e.g., blood) surrounding the electrode lead 3508 when implanted, for example blood glucose levels.

[0504] In examples, the tubular housing 3504 may have an outer diameter of less than about 5 millimetres, for example between about 1 millimetre and about 5 millimetres, for example between about 1 millimetre and about 3 millimetres, for example about 3 millimetres. The tubular housing 3504 may have a length of up to about 30 millimetres, for example up to about 25 millimetres, for example up to about 20 millimetres, for example about 20 millimetres. In examples, the electrode lead 3508 may have a diameter of between about 0.3 millimetres to about 1.5 millimetres, for example between about 0.5 millimetres and 1.3 millimetres, for example about 0.8 millimetres. The electrode lead 3508 may have a length of up to about 200 millimetres, for example up to about 150 millimetres, for example up to about 120 millimetres, for example about 120 millimetres. The electrodes 3520 may each have a length (along the electrode lead 3508) of up to about 15 millimetres, for example up to about 10 millimetres, forexample up to about 5 millimetres, for example about 3 millimetres. The electrodes 3520 may be spaced from each other along the electrode lead 3508 by at least 2 millimetres, for example at least 3 millimetres, for example at least 5 millimetres.

[0505] However, it will be appreciated that the dimensions of the tubular housing 3504 would correspond to the size of the electronics assembly 3506 within the tubular housing 3504, and the length of the electrode lead 3508 would correspond to the anatomy surrounding the target nerve, so a shorter or longer electrode lead 3508 may be appropriate depending on the depth of the nerve within the patient's tissue.

[0506] When the medical implant 3500 is implanted in the patient, it is positioned below the surface of their skin, in particular below the epidermis. The tubular housing 3504 may be positioned in the dermis or in the subcutaneous tissue. Positioning the tubular housing 3504 in the subcutaneous tissue, at a relatively shallow implantation depth, may be beneficial to reduce damage and / or irritation to the patient. In addition, implanting the tubular housing 3504 in the subcutaneous tissue may provide for efficient wireless power transfer due to the shorter distance and less intermediate tissue.

[0507] When the medical implant 3500 is implanted in the patient, the electrode lead 3508 extends from the tubular housing 3504, through the underlying tissue, in particular muscle, to a position proximal to the target nerve. The electrode lead 3508 is positioned such that the electrodes 3520 are close to, or even in contact with, the nerve, and so the electrodes 3520 can be used to sense neural signals of the nerve and / or to stimulate the nerve.

[0508] FIG. 29 shows an enlarged view of a front end 3551 of the medical implant 3500. As shown in FIG. 29, the housing assembly 3502 comprises a feedthrough 3516 comprising one or more feedthrough connectors 3518 connected to the electronics assembly 3506 and extending to a terminal end 3526 of the feedthrough 3516. The coupling between the electronics assembly 3506 and feedthrough 3516 is best shown in FIG. 29 below and described in the accompanying description.

[0509] The feedthrough 3516 may be shaped to form an extension of the tubular housing 3504. For example, where the tubular housing 3504 is cylindrical, the feedthrough 3516 may be cylindrical. Where the tubular housing 3504 is octagonal, the feedthrough 3516 may be octagonal and positioned such that external faces of the tubular housing 3504 align with external faces of the feedthrough 3516. In some examples, the tubular housing 3504 and the1feedthrough 3516 may form a stepped interface. However in preferred examples, the tubular housing 3504 and the feedthrough 3516 may form a level interface.

[0510] In examples, the lead connector 3524 may be elongate and extend between a proximal end 3536 (proximal to the housing assembly 3502) and a distal end 3538 (distal from the housing assembly 3502, along a length of the lead connector 3524). The proximal end 3536 of the lead connector 3524 may be attached to the housing assembly 3502 and aligned such that the proximal end 3536 is substantially perpendicular to a longitudinal axis 3534 of the housing assembly 3502. In particular, the proximal end 3536 of the lead connector may be directly attached to the feedthrough 3516 such that the proximal end 3536 extends perpendicular to the longitudinal axis 3534 of the housing assembly 3502. The lead connector 3524 may extend radially from the front end 3551 of the housing assembly 3502.

[0511] In this example, the electrode lead 3508 is coupled to the distal end 3538 of the lead connector 3524. Each of the lead wires 3510 extend substantially parallel to the length of the lead connector 3524.

[0512] The lead wires may be distributed across a width of the lead connector 3524. In this example, the lead wires 3510 are evenly spaced across the width of the lead connector 3524. Each of the lead wires 3510 may be surrounded by an electrically insulative coating 3564. Beneficially, this may prevent neighbouring lead wires 3510 from bridging. An attachment portion 3511a, 3511b, 3511c, 3511 d, 3511e of each of the lead wires 3510a, 3510b, 3510c, 3510d, 3510e is attached (e.g., soldered) at a respective attachment point to the lead connector 3524. The attachment portions 3511a, 3511b, 3511c, 3511 d, 3511e are exposed portions of the lead wires 3510 that are not covered by the electrically insulative coating 3564.

[0513] In this example, the lead wires 3510 are coupled to the distal end 3538 of the lead connector 3524 in a staggered arrangement. The attachment points are arranged such that for all directly neighbouring lead wires 3510, the attachment points are positioned at different longitudinal positions along the lead connector 3524. There is no overlap between the exposed attachment portions 3511a, 3511b, 3511c, 3511 d, 3511e of directly neighbouring lead wires 3510. This configuration may prevent solder from bridging between neighbouring lead wires 3510. This may allow each lead wire 3510a, 3510b, 3510c, 351 Od, 3510e to carry an independent electrical-signal for their respective electrodes 3520a, 3520b, 3520c, 3520c, 3520d, 3520e.

[0514] In this example, the attachment points are arranged in a arrowhead arrangement. However, the attachment points may be positioned in any configuration. In particular, the attachment points may be positioned such that the attachment points of directly neighbouring lead wires 3510 are positioned at different longitudinal positions along the lead connector 3524. For example, each consecutive attachment point along the width of the lead connector 3524 may be positioned progressively closer to the proximal end 3536. In another example, the attachment points may be in an alternating (e.g., zig-zig) arrangement.

[0515] As shown in FIG. 29, the lead connector 3524 may comprise an attachment plate 3542 coupled to the front end 3551 of the housing assembly 3502 to attach the lead connector 3524 to the housing assembly 3502. In this example, the one more feedthrough connectors 3518 comprise a plurality of pins 3560 which project through the attachment plate 3542. The number of the plurality of pins may equal the number of lead wires 3510. In this example, there are five lead wires 3510 and five pins. However, it will be understood that there may be any number of lead wires for example the electrode lead may instead comprise one, two, three, four, six or more lead wires. Similarly, the one or more feedthrough connectors may comprise any number of pins, e.g., one, two, three, four, six or more pins. Each of the plurality of pins 3560 may be attached to the attachment plate 3542 and electrically connect the attachment plate 3542 to the electronics assembly 3506.

[0516] The lead connector 3524 further comprises a flexible substrate 3530 which is bendable to vary an angle between the electrode lead 3508 and the housing assembly 3502. A first end 3531 of the flexible substrate 3530 is coupled to the attachment plate 3542. A second end 3532 of the flexible substrate 3530, opposite the first end 3531 defines the distal end 3538 of the lead connector 3524.

[0517] The flexible substrate 3530 may comprise one or more conducting paths 3528 provided in or on the flexible substrate 3530. In this example, the one or more conducting paths 3528 are provided on the flexible substrate 3530 and the flexible substrate 3530 essentially consists of a flexible PCB. In examples, the flexible substrate may be a 2D PCB, which may be a flat moulded part with electrical tracks formed in a plane within the moulded part.

[0518] In this example, the flexible substrate 3530 comprises five conducting paths 3528. In other examples, the flexible substrate 3530 may comprise two, three, four, six or more conducting paths 3528. The number of conducting paths 3528 may equal the number of lead wires 3510. Each of the lead wires 3510 may be connected to a respective one of theconducting paths 3528 to electrically connect that lead wire 3510 to a respective one of the feedthrough connectors 3518 (via the attachment plate 3542).

[0519] The attachment plate 3542 may comprise or essentially consists of a rigid substrate having one or more conductive traces 3546. In this example, the rigid substrate comprises five conductive traces 3546. In other examples, the rigid substrate may comprise two, three, four, six or more conductive traces 3546. Each of the conductive traces 3546 may electrically connect a respective one of the feedthrough connectors 3518 to a respective one of the conducting paths 3528 of the flexible substrate 3530. In FIG. 29, only one of the conducting paths 3528 of the flexible substrate 3530 and one of the conductive traces 3546 of the rigid substrate are shown for clarity.

[0520] The rigid substrate may be a rigid PCB 3544. The conductive traces 3546 may be printed connections disposed on a front surface of the rigid PCB 3544. Each of the feedthrough pins 3560 may be electrically connected (e.g., soldered) to a respective one of the conductive traces 3546. Providing a rigid substrate may prevent physical detachment of the conductive traces 3546 from the feedthrough pins 3560 during bending of the flexible substrate 3530.

[0521] As shown in FIG. 29, the first end 3531 of the flexible substrate 3530 is fixed to the attachment plate 3542. The flexible substrate 3530 is structured as a cantilevered beam 3600 that projects away from the housing assembly 3502. In this example, the cantilevered beam 3600 has a rectangular cross-section. The length 3602 of the cantilevered beam 3600 may be greater than or equal to: 1 mm; 2 mm; 3 mm; or 4 mm. The length 3602 may be less than: 5mm; 4mm; 3mm; or 2mm. Preferably the length 3602 may be between 3 mm and 4.5 mm. The length 3602 may be sufficient for the lead connector 3524 to project over a peripheral edge 3540 of the housing assembly 3502. A width 3604 of the cantilevered beam 3600 (measured perpendicular to the longitudinal axis of the housing assembly 3502) may be greater than or equal to: 0.2 mm; 0.4 mm; 0.6 mm; or 0.8 mm. The width 3604 may be less than: 1 mm; 0.8 mm, 0.6 mm; or 0.4 mm. Preferably, the width 3604 may be between 0.4 mm and 0.8 mm. A depth 3606 of the beam, measured perpendicular to the width 3604 and length 3602, may be greater than or equal to: 0.02 mm; 0.05 mm; 0.07 mm or 0.1 mm. The depth 3606 of the cantilevered beam 3600 may be less than: 0.02 mm; 0.05 mm; 0.07 mm or 0.1 mm. Preferably, the depth 3606 may be 0.07 mm. The dimensions of the cantilevered beam 3600 may be selected to achieve the required deflection of the flexible substrate 3530 upon insertion.

[0522] In FIG. 29, the flexible substrate 3530 is shown in an un-deformed configuration - when no external forces act on the flexible substrate 3530. In this configuration, the cantilevered beam 3600 is in a neutral position. In the neutral position, the cantilevered beam 3600 may be straight and a full length of the beam may project radially away from the housing assembly 3502. The flexible substrate 3530 may adopt this position when deployed in the tissue of a patient.

[0523] FIG. 30 shows the front end 3551 of the medical implant 3500 when the flexible substrate 3530 is in a deformed configuration. The flexible substrate 3530 may adopt this configuration prior to the medical implant 3500 being deployed into the tissue of the patient, as described hereinafter in relation of FIG. 36.

[0524] In FIG. 30, the flexible substrate 3530 is deformed so that the second end 3532 deflects downwards towards a rear end 3552 of the housing assembly 3502. In this position, the cantilevered beam 3600 is bent into an arcuate shape. The flexible substrate 3530 may also be operable to bend in the reverse manner so that the second end 3532 deflects upwards away from the rear end 3552 of the housing assembly 3502. In some examples, the flexible substrate 3530 may be operable to bend into a wave-like profile having two or more points of inflection. The flexible substrate 3530 may be operable to deflect ±90° from the neutral position.

[0525] Flexibility of the flexible substrate 3530 may allow for greater manoeuvrability of the medical implant 3500 during insertion. As will be described later in relation to FIG. 37, during insertion of the medical implant 3500, the electrode lead 3508 may be delivered as an insertion angle and then the housing assembly 3502 delivered at a deployment angle different to the insertion angle. The flexible substrate 3530 may be bent during deployment of the electrode lead 3508 and / or the housing assembly 3502 to vary an angle between the electrode lead 3508 and the housing assembly 3502. For example, the flexible substrate 3530 may be bent from an un-deformed configuration to a deformed configuration, or visa versa, or bent from one deformed configuration to another deformed configuration. In some examples, the flexible substrate 3530 may be bent in a first direction during or prior to deployment of the electrode lead 3508 and bent in a second direction (substantially reverse to the first direction) during or prior to deployment of the housing assembly 3502.

[0526] Bending of the flexible substrate 3530 may allow a user to more accurately and independently position the electrode lead 3508 with respect to the housing assembly 3502. For example, it may be preferable for the tubular housing 3504 to be positioned just below thesurface of their skin (i.e., below the epidermis), in the dermis or in the subcutaneous tissue. Positioning the tubular housing 3504 at a relatively shallow implantation depth, may provide for efficient wireless power transfer and communication between the medical implant 3500 and the external device. In addition, such positioning may also be beneficial to reduce damage and / or irritation to the patient. Meanwhile, the electrode lead 3508 may be positioned to extend from the tubular housing 3504, through the underlying tissue (e.g., muscle) to a location proximal to the target nerve. The electrode lead 3508 may be positioned such that the electrodes (not shown) are close to or contact the target nerve.

[0527] Optimal positions of the electrode lead 3508 and of the housing assembly 3502 may vary for different implantation sites used to access different target nerves. In addition, there may also be variation in the optimal position of the electrode lead 3508 and / or housing assembly 3502 due to the specific anatomy of each patient. The flexibility of the electrode lead 3508 allows the medical device to at least partially account for the various electrode 3520- housing assembly 3502 configurations to which the medical implant 3500 must be able to conform.

[0528] In existing implant designs, bending of the electrode lead may be localized at or near the lead connector. The applicant has appreciated that extensive deformation of the electrode lead, required for accurate positioning of medical implants, can cause failure of the lead wires within the electrode lead. The provision of the flexible substrate 3530 may ameliorate this issue. The flexible substrate 3530 may accommodate at least part of the required deformation thereby reducing the required bending moment of the electrode lead 3508. The flexible substrate 3530 may be operable to bend to adapt for various relative positions between the electrode lead 3508 and the housing assembly 3502. This may give a user may more flexibility in the independent positioning of the electrode lead 3508 and the housing assembly 3502.

[0529] In addition, the flexibility of the flexible substrate 3530 may allow the medical implant 3500 to accommodate for stretching or flexing of the patient's tissue after implantation of the medical implant 3500. Bending the flexible substrate 3530 may relive pressure that may otherwise cause electrodes 3520 to migrate away from the target nerve site at which they are implanted. In this way, the flexible substrate 3530 may prevent unwanted migration of the electrode lead 3508 thereby improving the effective lifetime of the medical implant 3500 postimplantation.

[0530] In some examples, the medical implant 3500 may include one or more anti-migration members (not shown). The anti-migration members may be provided on the tubular housing 3504 and / or on the electrode lead 3508 and function to hold the medical implant 3500 in position in the patient’s tissue. The anti-migration members may be configured to deploy during implantation of the medical implant 3500 in the patient.

[0531] Each of the conducting paths 3528 (not shown in FIG. 30) may be arranged in a common plane 3608 of the flexible substrate 3530. In this example, each of the conducting paths 3528 extend along a top surface of the flexible substrate 3530 from the first end 3531 to the second end 3532 (i.e., along the length 3602 of the flexible substrate 3530). As shown in FIG. 29, when the flexible substrate 3530 is in its un-deformed configuration, the common plane 3608 may be perpendicular to the longitudinal axis 3534 of the housing assembly 3502. When the flexible substrate 3530 is bent, e.g., as shown in FIG. 30, each of the conducting paths 3528 are deformed by the same amount as each of the other conducting paths 3528.

[0532] As shown in FIG. 30, the flexible substrate 3530 may be operable to bend in a first direction perpendicular to the common plane 3608. The flexible substrate 3530 may not be operable to bend in a second direction within the common plane 3608. In this example, the width 3604 of the cantilevered beam 3600 is greater than the depth 3606 of the beam. In other examples the width 3604 may be at least 10%, 50%, 100% or 200% greater than the depth 3606. As such, a significantly smaller force may be required to cause deflection of the cantilevered beam 3600 perpendicular to the common plane 3608 (i.e., in the plane of the page as shown in FIG. 30) than transverse bending causing deflection parallel to the common plane 3608 (i.e., into or out of the page as shown in FIG. 30).

[0533] This arrangement may ensure that each of the conducting paths 3528 are subjected to the same limited deflection as each of the other of the conducting paths 3528 when the flexible substrate 3530 is bent. In contrast, for a transverse bending mode, conducting paths 3528 at either side of the flexible substrate 3530 would experience significant contraction or stretching which could damage or sever the conducting paths 3528. By configuring the common plane 3608 to be positioned along an easy-axis of the cantilevered beam 3600, the reliability of the medical implant 3500 may be improved.

[0534] In addition, the orientation of the lead connector 3524 with respect to the tubular housing 3504 may further improve the reliability of the medical implant 3500. WO2023247333A1 describes a known medical implant for neurostimulation. In thisarrangement, a lead connector is coupled to an end of a housing such that a lead is co-axial with the housing. Implantation may require the housing assembly to be positioned shallow and substantially parallel with a patient's skin. In contrast, the target nerve is typically located deeper below the surface requiring the electrode lead to extend away from the housing assembly, at a significant angle to the housing assembly. In the present invention, the proximal end 3536 of the lead connector 3524 is coupled to the housing assembly 3502 so as to project substantially radially away from the housing assembly 3502. This orientation may minimize the total deflection required to meet the optimal implant positions for the electrode lead 3508 and the housing assembly 3502 in the patient.

[0535] FIG. 31 shows a cross-sectional view of the housing assembly 3502 in isolation from other components of the medical implant 3500.

[0536] As shown in FIG. 31, the electronics assembly 3506 is housed within the tubular housing 3504. In examples, the electronics assembly 3506 comprises a circuit board 3702, such as a rigid PCB (e.g., PCB 220), housed within the tubular housing 3504.

[0537] The circuit board 3702 may extend between a front end and a rear end of the tubular housing 3504, and may be supported at both ends. The electronics assembly 3506 includes various electronics components mounted to one or both sides of the circuit board 3702, including for example a processor or controller, a wireless communications receiver / transmitter, a wireless power receiver, and / or sensor electronics.

[0538] An antenna (not shown) may be housed within the tubular housing 3504. In one example, the antenna may be helical and wound around the circuit board 3702. The antenna may be a wireless power antenna adapted to receive wireless power transmitted from the external device. In other examples, the electronics assembly 3506 may include more than one antenna within the tubular housing 3504. In examples, there may be multiple wireless power antennas for receiving wireless power, for example at different wavelengths so that wireless power transmission can be improved.

[0539] In examples, the electronics assembly 3506 may also include a wireless communications antenna within the tubular housing 3504. The wireless communications antenna may instead be provided in the electrode lead 3508 an example of which is shown in FIG. 35.

[0540] The tubular housing 3504 may be formed of an electrically insulative material, preferably a ceramic material, in particular zirconia. The housing assembly 3502 may comprisea weld ring 3704 attached to a front end of the tubular housing 3504. The weld ring 3704 may preferably comprise metal, in particular a platinum-iridium alloy or titanium. The weld ring 3704 may be joined to the tubular housing 3504, for example by adhesive, welding, or brazing. The weld ring 3704 may hermetically seal the front end of the tubular housing 3504.

[0541] In the example shown in FIG. 31, the feedthrough 3516 is attached to a front end of the weld ring 3704. In examples, the feedthrough 3516 is metallic, in particular a platinum-iridium alloy or titanium, and is joined to the weld ring 3704 by welding. The feedthrough 3516 may hermetically seal the front end 3551 of the housing assembly 3502.

[0542] The lead connector (not shown) may be physically coupled to the feedthrough 3516 e.g., by soldering and / or an adhesive. In examples, the feedthrough connectors 3518 provide an electrical connection between the attachment plate 3542 and the circuit board 3702 within the tubular housing 3504 thereby electrically connecting the electrode lead 3508 to the electronics assembly 3506. In the example shown in FIG. 31, the feedthrough connectors 3518 are pins 3560 which project through an end surface 3517 of the feedthrough 3516. Only three of the five feedthrough pins 3560 are shown in FIG. 31.

[0543] The medical implant 3500 may further comprise an end cap 3706 provided at a rear end 3552 of the housing assembly 3502. The end cap 3706 may be sealed in the rear end of the tubular housing 3504, for example by brazing, bonding or adhesive. The end cap 3706 may hermetically seal the rear end of the tubular housing 3504.

[0544] In some examples, the end cap 3706 may be electrically connected to the circuit board 3702. In the example shown in FIG. 31, the electronics assembly 3506 includes a wire 3708 which electrically connects the circuit board 3702 to the end cap 3706.

[0545] In some examples, the end cap 3706 may act as an additional electrode 3520 to sense or detect neural signals or other non-neural parameters of the patient, or to provide electrical stimulation to stimulate a target nerve of the patient.

[0546] In examples, the end cap 3706 may provide an electrical feedthrough for the rear end 3552 of the housing assembly 3502. This may be used to connect additional electrodes attached to an external surface of the tubular housing 3504 to the circuit board 3702 inside the tubular housing 3504 while maintaining the hermeticity of the rear end 3552 of the housing assembly 3502.

[0547] I examples, the end cap 3706 includes a socket 3710 configured to receive an end of the circuit board 3702. The socket 3710 may be cuboidal. In other examples the socket 3710may be circular or have another polygonal shape, such as triangular or hexagonal. The socket 3710 may be formed on an inner surface of the end cap 3706 that faces an interior of the tubular housing 3504. The socket 3710 may provide electrical connection between the circuit board 3702 and the end cap 3706.

[0548] The electronics assembly 3506 may comprise a capacitor (not shown) such as a foil capacitor. The capacitor may be mounted directly to the circuit board 3702 or may be positioned proximal to the end cap 3706 about the longitudinal axis 3534.

[0549] In some examples, the tubular housing 3504 may include a piezoelectric material, for example formed as an insert. In alternative examples, the feedthrough 3516 may additionally or alternatively comprise a piezoelectric material. In alternative examples, the end cap 3706 may comprise or consist essentially of a piezoelectric material. The piezoelectric material may be electrically connected with the circuit board 3702 and may be used to detect a parameter of the patient (e.g., detecting body temperature, blood pressure, or heart rate when the medical implant 3500 is implanted).

[0550] In some examples, the medical implant 3500 may comprise a flexible sleeve 3802 which surrounds at least part of the lead connector 3524. FIG. 32 shows the medical implant 3500 with the flexible sleeve 3802 included. The flexible sleeve 3802 may be attached to the housing assembly 3502 e.g., by an adhesive. As shown in FIG. 32, the flexible sleeve 3802 is arranged to cover the attachment plate 3542 and at least part of the flexible substrate 3530.

[0551] In this example, the flexible sleeve 3802 is formed of two parts: a body 3806 and an elongate pipe 3808. The body 3806 is attached to the end surface 3517 of the feedthrough 3516. The body 3806 is at least partially hollow. In this example, the body 3806 is substantially cylindrical but it will be understood that the body 3806 may have any partially hollow shape (e.g., any regular or irregular shaped cross-section such as an octagonal cross-section or an oval shaped cross-section). The body 3806 may be shaped to form an extension of the feedthrough 3516. For example, where the feedthrough 3516 is cylindrical, the body 3806 may be cylindrical. Where the feedthrough 3516 is octagonal, the body 3806 may be octagonal and positioned such that external faces of the feedthrough 3516 align with external faces of the body 3806. In some examples, the feedthrough 3516 and the flexible sleeve 3802 may form a stepped interface. However in preferred examples, the feedthrough 3516 and the flexible sleeve 3802 form a level interface. The body 3806 may be co-axial with the housing assembly 3502.

[0552] In examples, the attachment plate 3542 is received within the body 3806 and the body 3806 extends around a perimeter of the attachment plate 3542. The flexible sleeve 3802 may comprise an end cover 3810 which closes an end of the body 3806 distal from the tubular housing 3504. The body 3806 may be arranged to cover the attachment plate 3542 and the feedthrough connectors 3518.

[0553] In examples, the body 3806 has a radial aperture 3818. The elongate pipe 3808 may be radially attached to the body 3806 so as to surround the radial aperture 3818 of the body 3806. Together, the elongate pipe 3808 and the body 3806 may form a continuous conduit therebetween. In this example, the flexible substrate 3530 is at least partially received within the elongate pipe 3808. In some examples, the flexible substrate 3530 may be completely received within the flexible sleeve 3802. In this example, the second end 3532 of the flexible substrate 3530 extends beyond the flexible sleeve 3802 so the lead connector 3524 is not completely received within the flexible sleeve 3802.

[0554] In this example, the body 3806 is integrally formed with the elongate pipe 3808 so as to form a single component. In other examples, the elongate pipe 3808 may be attached to the body 3806, e.g., using an adhesive.

[0555] In some examples, the flexible sleeve 3802 may contact the attachment plate 3542 and / or the feedthrough connectors 3518 and / or the flexible substrate 3530. For example, the flexible sleeve 3802 may be shrink wrapped around the lead connector 3524. In the example shown in FIG. 32, the flexible sleeve 3802 is separated from the attachment plate 3542, the feedthrough connectors 3518 and the flexible substrate 3530. This separation may prevent internal components from perforating the flexible sleeve 3802 during bending of the lead connector 3524.

[0556] The flexible sleeve 3802 may be made form any suitable material. For example, the flexible sleeve 3802 may comprise or essentially consist of silicone or pellethane. The flexible sleeve 3802 is operable to bend to accommodate bending of the flexible substrate 3530. The flexible sleeve 3802 may be operable to accommodate a maximum deflection of the flexible substrate 3530.

[0557] The flexible sleeve 3802 may prevent ingress of fluids from the patient's tissue into the feedthrough 3516 and lead connector 3524. Protecting the lead connector 3524 and the feedthrough connectors 3518 may improve the lifetime of the medical implant 3500.

[0558] The flexible sleeve 3802 may act to oppose bending of the flexible substrate 3530. For example, the flexible sleeve 3802 may reduce a strain associated with bending the flexible substrate 3530 for a given applied force. As such, the provision of the flexible sleeve 3802 may increase the effective Young's modulus of the flexible substrate 3530. This may prevent excessive strain of the flexible substrate 3530 during bending which could cause damage to the conducting paths 3528.

[0559] As shown in FIG. 32, the electrode lead 3508 may comprise a lead cover 3804 arranged to surround a first portion 3812 of the electrode lead 3508. This lead cover 3804 is omitted in FIG. 28 to FIG. 31 for clarity but is shown in FIG. 32.

[0560] As shown, the lead cover 3804 is attached to the flexible sleeve 3802 e.g., by an adhesive. In alternate examples, the flexible sleeve 3802 may be integrally formed with the lead cover 3804 so as to form a single component.

[0561] The lead cover 3804 may extends from the flexible sleeve 3802 to cover a first portion 3812 of the electrode lead 3508. A second portion (not shown) of the electrode lead 3508, comprising the electrodes (not shown), may not be covered by the lead cover 3804. This arrangement leaves the electrodes exposed to surrounding patient tissue in use (for detecting neural signals or stimulating the target nerve).

[0562] In examples, the lead cover 3804 surrounds the second end 3532 of the flexible substrate 3530. A shape of the lead cover 3804 varies along its length. A first side 3814 of the lead cover 3804 may have an internal diameter suitable for receiving the second end 3532 of the flexible substrate 3530. A second side 3816 of the lead cover 3804, opposite the first side 3814, may have a smaller internal diameter than the first side 3814 and receives the electrode lead 3508.

[0563] The lead cover 3804 may be flexible and operable to accommodate bending of the flexible electrode lead 3508. The lead cover 3804 may comprise or essentially consist of silicone or pellethane. The lead cover 3804 may prevent or ameliorate fluid ingress from the surrounding tissue. For example, the lead cover 3804 may protect the conducting paths 3528 and the attachment points of the lead wires 3510. A length of the lead cover 3804, along the electrode lead 3508, may be selected to prevent fluid at / on the second portion of the electrode lead 3508 which is exposed from travelling along the electrode lead 3508 to the attachment points. For example, the lead cover 3804 may have a length of at least; 1 cm, 2 cm, 3 cm, 4 cm or 5 cm. Beneficially, this may prevent unwanted bridging between the lead wires 3510.

[0564] In some examples, each of the lead wires 3510 are individually electrically insulated. This may prevent electrical signals carried in the lead wires 3510 from conducting between the lead wires 3510.

[0565] In other examples, each of the lead wires 3510 may not be individually electrically insulated. In such examples, the lead cover 3804 may electrically insulate at least part of the lead wires 3510 from the patient's tissue.

[0566] As shown in FIG. 32, a first section 3821 of the electrode lead 3508 may be arranged on the common plane 3608 (i.e., top surface) of the flexible substrate 3530. The first section3821 may be bonded to the lead connector 3524 by way of an adhesive or solder. This may reduce tension on the attachment points during bending of the electrode lead 3508. In the first section 3821, the lead wires 3510 may extend substantially parallel to the length of the lead connector 3524.

[0567] In examples, a second section 3822 of the electrode lead 3508 projects from the lead connector 3524. Within this second section 3822, the lead wires 3510 may extend away from the lead connector 3524. In the example shown in FIG. 32, the lead wires 3510 in the second section 3822 project substantially parallel to the length of the lead connector 3524. However, it will be understood that upon bending the electrode lead 3508 the lead wires 3510 in the second section 3822 will be displaced out of this configuration. For example, in the second section3822 the lead wires 3510 may adopt an arcuate shape and / or have a curvilinear profile.

[0568] FIG. 33 shows an example of the feedthrough 3516 of the medical implant 3500 described above. In particular, as shown in FIG. 33, in this example the feedthrough 3516 comprises pins 3560 extending therethrough to electrically connect the electronics assembly 3506 to the lead wires 3510. In this example, the pins 3560 are formed as ends of the lead wires 3510 that are moulded into the feedthrough 3516, so that there is no connection between the pins 3560 and the lead wires 3510. This may improve the resilience of the feedthrough connection during bending of the electrode lead and lead wires 3510.

[0569] In similar examples, ends of the conductive traces (3546, described above) may be moulded into the feedthrough 3516 in a similar manner.

[0570] In some examples, the electrode lead 3508 comprises a first helical portion 3900. FIG. 34 shows an enlarged view of the first helical portion 3900. In this example, the first helical portion 3900 forms part of the second section 3822 of the electrode lead 3508. In otherexamples, the second section 3822 may effectively consist of the first helical portion 3900 and the electrodes 3520 (not shown).

[0571] The first helical portion 3900 electrically connects the electrodes 3520 to the electronics assembly 3506 via the lead connector 3524. The first helical portion 3900 may or may not comprise the electrodes 3520.

[0572] In the first helical portion 3900, each of the lead wires 3510 have a helical shape. The helical shape may be preferable to a non-coiled shape, offering greater flexibility and minimizing point stresses during bending of the electrode lead 3508.

[0573] In this example, the first helical portion 3900 has a first diameter 3901 which is substantially constant along a length of the first helical portion 3900. The first helical portion 3900 may comprise a multi-filar array. For example, the first helical portion 3900 may be formed using a multi-filar coil winder including a mandrel. In some embodiments, the coiled lead wires 3510 may be joined together e.g., via soldering or welding. The coiled lead wires 3510 may be joined together whilst they are on the mandrel to maintain the coil structure upon removal of the first helical portion 3900 from the mandrel.

[0574] The first helical portion 3900 is received within the lead cover 3804. The lead cover 3804 extends around the full circumference of the first helical portion 3900. The electrodes 3520 may not be covered by the lead cover 3804. This arrangement leaves the electrodes 3520 exposed to surrounding patient tissue in use for detecting neural signals or stimulating the target nerve.

[0575] In some examples, the electrode lead 3508 may additionally comprise a second helical portion 4000.

[0576] FIG. 35 shows part of the electrode lead 3508 showing the second helical portion 4000. The second helical portion 4000 has a second diameter 4002 which is substantially constant along a length of the second helical portion 4000. The second diameter 4002 of the second helical portion 4000 is greater than the first diameter 3901 of the first helical portion 3900. In this example, the second helical portion 4000 spirals around an outside of the first helical portion 3900.

[0577] In examples, the length of the second helical portion 4000 is less than the length of the first helical portion 3900. The second helical portion 4000 may spiral around an outside of a section of the first helical portion 3900, proximal to the housing assembly 3502 (not shown in FIG. 35). The second helical portion 4000 may only surround part of the full length of the firsthelical portion 3900. A section of the first helical portion 3900, distal from the housing assembly 3502, may not be surrounded by the second helical portion 4000. In examples, the first helical portion 3900 and the second helical portion 4000 are co-axial.

[0578] In some examples, the first helical portion 3900 and the second helical portion 4000 may be coupled to the distal end 3538 of lead connector 3524 (not shown).

[0579] The first helical portion 3900 and / or second helical portion 4000 may be operable as a wireless power antenna to supply power to the electronics assembly 3506.

[0580] In examples, the second helical portion 4000 is operable as a wireless power antenna to supply power to the electronics assembly 3506. The second helical portion 4000 may not comprise any exposed electrodes for nerve stimulation.

[0581] In examples, the medical implant 3500 is configured such that the electronics assembly 3506 (not shown in FIG. 35) provides signals to the first helical portion 3900 for the electrodes 3520 to stimulate one or more target nerves. In examples, the medical implant 3500 may be configured such that the electronics assembly 3506 receives, and optionally process, signals from the first helical portion 3900 representing neural signals or other non-neural parameters of the patient.

[0582] The second helical portion 4000 includes one or more additional lead wires 4004. In the example shown in FIG. 35, the second helical portion 4000 comprises one additional lead wire 4004. The additional lead wire 4004 may be coiled using a rotating mandrel. It will be understood that the second helical portion 4000 may instead include a plurality of lead wires. In some examples, the second helical portion 4000 may comprise a multi-filar array. For example, the second helical portion 4000 may be formed using a multi-filar coil winder including a mandrel. In some embodiments, the plurality of coiled additional lead wires 4004 may be joined together e.g., via soldering or welding. The plurality of coiled additional lead wires 4004 may be joined together whilst they are on the mandrel to maintain the coil structure upon removal of the second helical portion 4000 from the mandrel.

[0583] As shown in FIG. 35, the medical implant 3500 may comprise an outer cover 4006 which houses the second helical portion 4000. The outer cover 4006 may comprise or essentially consist of silicone or pellethane. In this example, the outer cover 4006 extends around the full circumference of the lead cover 3804 terminating at a position part- way along the length of the lead cover 3804. The electrodes (not shown), of the electrode lead 3508 are not covered by the outer cover 4006.

[0584] In some examples, the outer cover 4006 may be omitted and the lead cover 3804 may surround both the first helical portion 3900 and the second helical portion 4000. In such examples, a diameter of the lead cover 3804 may vary along its length to accommodate the difference in the diameter between the first helical portion 3900 and the second helical portion 4000.

[0585] As shown in FIG. 35, the second helical portion 4000 is radially offset from the first helical portion 3900. This radial offset may enable more efficient power transfer than would otherwise be achieved.

[0586] FIG. 36 shows a delivery device 4100 for implanting the medical implant 3500 into a patient's tissue. The delivery device 4100 is substantially as described in applicant's international PCT application PCT / EP2021 / 085998 (WO2022129234A1) which is incorporated herein by reference.

[0587] The delivery device 4100 comprises a delivery sleeve 4102. The medical implant 3500 is received within the delivery sleeve 4102. In this example, the delivery sleeve 4102 includes a first needle 4106 and a second needle 4108. The delivery device 4100 includes a handle 4104 and the first needle 4106 and the second needle 4108 extend parallel to the handle 4104.

[0588] The first needle 4106 is larger than the second needle 4108, i.e., has a lumen with a larger internal diameter. The second needle 4108 extends further from the handle 4104 than the first needle 4106.

[0589] The medical implant 3500 is arranged within the delivery sleeve 4102 such that a front end 3551 of the housing assembly 3502 from which the electrode lead 3508 extends is directed oppositely to an opening 4110 of the delivery sleeve 4102 through which the electrode lead 3508 is to be deployed. The housing assembly 3502 is held in a lumen of first needle 4106.The electrode lead 3508 extends from the lead connector 3524 into the second needle 4108 and is held in a lumen of the second needle 4108. As shown, the electrode lead 3508 overlies the housing assembly 3502 within the delivery sleeve 4102 and extends towards the opening 4110.

[0590] In this example, the second needle 4108 is retractable relative to the handle 4104. The second needle 4108 may be received in the lumen of the first needle 4106, or may extend alongside the first needle 4106.

[0591] FIG. 37 shows a method 4200 of implanting a medical implant, for example a neurostimulator or diagnostic implant, such as the medical implant 3500, in a patient. In this example, the medical implant 3500 is the medical implant 3500 of FIG. 28.

[0592] The method 4200 comprises a first step 4201 of providing a delivery device for inserting the medical implant 3500 into the patient's tissue. The delivery device comprises a delivery sleeve with the medical implant 3500 received therein. In this example, the delivery device is the delivery device 4100 shown in FIG. 36 and described in the accompanying description. The medical implant 3500 may be arranged within the delivery sleeve 4102 such that the front end 3551 of the housing assembly 3502 from which the electrode lead 3508 extends is directed oppositely to the opening 4110 of the delivery sleeve 4102 through which the electrode lead 3508 is to be deployed. The electrode lead 3508 may overlie the housing assembly 3502 within the delivery sleeve 4102 and extends towards the opening 4110.

[0593] A second step 4202 of the method 4200 involves inserting part of the delivery sleeve 4102 into the patient’s tissue at an insertion angle and then deploying the electrode lead 3508 from within the delivery sleeve 4102 into the patient’s tissue. For example, the second needle 4108 may be at least particularly inserted into the patient’s tissue at the insertion angle. The electrode lead 3508 may be deployed from the opening 4110 into the patient's tissue positioned at the insertion angle. The electrode lead 3508 may be inserted at a first depth in the patient's tissue to position the electrode lead 3508 close to a target nerve. Optionally, the second needle 4108 may then be retracted to expose the electrode lead 3508. This step may include testing the electrodes 3520 to asses whether or not they are correctly positioned by the target nerve. If testing determines that the position of the electrode lead 3508 is not correct or not optimal, the second needle 4108 can be re-extended and the delivery sleeve 4102 can be repositioned. The above process can be repeated until the electrode lead 3508 is appropriately positioned

[0594] A third step 4203 of the method 4200 includes changing the orientation of the delivery sleeve 4102 with respect to the patient’s tissue. The third step 4203 may involve bending the flexible substrate 3530 to vary the angle between the electrode lead 3508 and the housing assembly 3502 received within the delivery sleeve 4102. For example, a user may use the handle 4104 to position the first needle 4106 at a deployment angle different to the insertion angle.

[0595] A fourth step of the method 4200 may include deploying the housing assembly 3502 from within the delivery sleeve 4102 into the patient’s tissue at the deployment angle. The housing assembly 3502 may be pushed out of the first needle 4106, for example using a pusher. After the housing assembly 3502 is deployed form the delivery sleeve 4102, the housing assembly 3502 may be positioned at a second depth in the patient's tissue which is shallowerthan the first depth. The position of the housing assembly 3502 in the patient's tissue may be selected to ensure the communication with the external device. After the housing assembly 3502 is appropriately positioned, the second needle 4108 may be fully retracted towards the handle 4104. The delivery device 4100 may be removed from the patient leaving the electrode lead 3508 and the housing assembly 3502 in the patient's tissue.

[0596] The steps of the method 4200 may be completed in any order which is consistent with each step. For example, steps 4201, 4202, 4203, 4204, 4205 may be completed in sequential (numerical) order as shown in FIG. 37.

[0597] FIGS. 38A to 38C illustrate part of an example medical implant 4300 as received in a part of a delivery device 4302, in particular a needle 4304 (second needle) of the delivery device 4302. The delivery device 4302 may be as described with reference to FIG. 17 or FIG. 26. The delivery device 4302 may be substantially as described in applicant's international PCT application PCT / EP2021 / 085998 (WO2022129234A1). The medical implant 4300 may be the medical implant of any other example described herein.

[0598] As with previous examples, the needle 4304 of the delivery device 4302 comprises an opening 4308 extending along the needle 4304. As illustrated, in this example the electrode lead 4306 of the medical implant 4300 comprises a plurality of keys 4310 arranged to extend into the opening 4308 in the needle 4304. The keys 4310 are firmly connected to the electrode lead 4306. As apparatus from FIG. 38C, the keys 4310 restrict, or prevent, rotation of the electrode lead 4306 within the needle 4304.

[0599] As shown most clearly in FIG. 38C, the keys 4310 extend from the electrode lead 4306 and into opening 4308. The keys 4310 extend in a radial direction such that an outer face of each key 4310 is less than the diameter of the needle 4304.

[0600] In this example the electrode lead 4306 also comprises a tine 4312. In the illustrated example there is one tine 4312 but there may be a plurality of tines 4312. The tine 4312 is arranged between two keys 4310. When the needle 4304 is overlapping with the tine 4312 it is held in a retracted position, against the electrode lead 4306, by the needle 4304. In particular, as shown in FIG. 38C, the tine 4312 is wider than the opening 4308 (and wider than the keys 4310) so that edges of the tine 4312 are retained under the needle 4304.

[0601] As shown in FIG. 38B, when the needle 4304 is retracted relative to the electrode lead (4306) (as described with reference to FIG.17 and FIG. 26), the tine 4312 is freed. The tine4312 then resiliently deflects to a deployed position. The tine 4312 acts against or within the patient’s tissue to anchor the electrode lead 4306.

[0602] When in the deployed position (FIG. 38B) the tine 4312 is angled away from the distal end of the electrode lead 4306 such that the tine 4312 prevents the electrode lead 4306 being pulled out of the tissue, for example as the needle 4304 is retracted further.

[0603] In the illustrated example the tine 4312 extends from one of the keys 4310, in particular from a proximal side of one key 4310. In other examples, the tine 4312 may extend from the electrode lead 4306 at a location spaced from the key 4310. There may be a plurality of tines 4312, for example one for each key 4310.

[0604] The tine 4312 is preferably a resiliently deformable material, and may for example be polymer or metal. In examples, the tine 4312 may comprise a silicone, a pellethane, or a polyurethane. In examples, the tine 4312 may comprise a metallic part (e.g., a titanium or nitinol part) covered with a softer material such as a polymer (e.g., a silicone, a pellethane, or a polyurethane). The metal part may be in a base part of the tine 4312, on the electrode lead 4306, for example only in the base part.Advantageously, the tine 4312 is thinner than the key 4310 disposed distally of the tine 4312. In this way, the key 4310 acts to protect the tine 4312 as the electrode lead 430 is progressed through the patient’s tissue.

[0605] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0606] Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. For example, the housing portion 102 of FIG. 1A may be directly substituted for any of the housing portions 700, 2800, 2900, 3000, 3100, of FIG. 18 to FIG. 24 or the housing assembly 3502. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps aremutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A medical implant, for example a neurostimulator or diagnostic implant, comprising: a housing assembly comprising: a tubular housing; an electronics assembly received at least partially within the tubular housing; and a feedthrough comprising one or more feedthrough connectors connected to the electronics assembly; an electrode lead comprising one or more lead wires; and a lead connector configured to attach the electrode lead to the housing assembly, having one or more conducting paths that electrically connect the lead wires to the one or more feedthrough connectors, wherein the lead connector comprises a flexible substrate and the one or more conducting paths are provided in or on the flexible substrate, the flexible substrate being bendable to vary an angle between the electrode lead and the housing assembly.

2. The medical implant of claim 1, wherein the flexible substrate comprises or essentially consists of a flexible PCB.

3. The medical implant of claim 1 or 2, wherein the one or more conducting paths are arranged in a common plane which is substantially perpendicular to a longitudinal axis of the housing assembly.

4. The medical implant of any one of claims 1 to 3, wherein the lead connector is elongate and extends between: a first end proximal to the housing assembly; and a second end distal from the housing assembly, along a length of the lead connector.

5. The medical implant of claim 4, wherein the first end of the lead connector is attached to the housing assembly and aligned such that the first end is substantially perpendicular to the longitudinal axis of the housing assembly.

6. The medical implant of claim 4 or 5, wherein the electrode lead is coupled to the second end of the lead connector, optionally wherein the one or more lead wires are coupled to the second end of the lead connector in a staggered arrangement.

7. The medical implant of any one of claims 4 to 6, wherein the length of the lead connector is sufficient for the lead connector to project over a peripheral edge of the housing assembly.

8. The medical implant of any one of claims 1 to 7, wherein the flexible substrate is operable to deflect between 30° and 250° relative to the housing portion, for example ±90° relative to the housing portion.

9. The medical implant of any one of claims 1 to 8, wherein the lead connector comprises an attachment plate which is coupled to the housing assembly and to the flexible substrate to attach the lead connector to the housing assembly, optionally wherein the one or more feedthrough connectors comprise a plurality of pins which are attached to the attachment plate and electrically connect the feedthrough to the flexible substrate.

10. The medical implant of claim 9, wherein the attachment plate comprises or essentially consists of a rigid substrate having one or more conductive traces that electrically connect the one or more feedthrough connectors to the one or more conducting paths of the flexible substrate.

11. The medical implant of claim 10, wherein the rigid substrate comprises or essentially consists of a rigid PCB.

12. The medical implant of any one of claims 9 to 11, wherein a first end of the flexible substrate is coupled to the attachment plate and a second end of the flexible substrate, opposite the first end of the flexible substrate, is coupled to the electrode lead such that each of the one or more lead wires are connected to a respective one of the one or more conducting paths.

13. The medical implant of any one of claims 1 to 12, further comprising a flexible sleeve which surrounds at least part of the lead connector.

14. The medical implant of claim 13, wherein the electrode lead comprises a lead cover arranged to surround a portion of the electrode lead.

15. The medical implant of claim 14, wherein the lead cover and / or the flexible sleeve comprises or essentially consists of silicone or pellethane.

16. The medical implant of any one of claims 1 to 15, wherein the tubular housing is a ceramic tubular housing for housing an electronics assembly and wherein the housing assembly comprises a housing portion, the housing portion comprising: the ceramic tubular housing having a first end with a first mating face; and a metallic connecting ring having a second end with a second mating face, and wherein the second mating face is brazed to the first mating face to form a flush joint between the metallic connecting ring and the ceramic tubular housing such that the first end and the second end form a level external surface of the housing portion.

17. The medical implant of claim 16, wherein the first end terminates in a first flat rim which defines the first mating face and the second end terminates in a second flat rim which defines the second mating face.

18. The medical implant of claim 17, the first mating face and / or the second mating face are oriented perpendicular to a longitudinal axis of the housing portion.

19. A delivery device for implanting the medical implant of any one of claims 1 to 16 into a patient's tissue, comprising a delivery sleeve and the medical implant received within the delivery sleeve.

20. A method of implanting a medical implant, for example a neurostimulator or diagnostic implant, in a patient comprising the steps of: providing a delivery device, for inserting the medical implant into the patient's tissue, comprising a delivery sleeve with the medical implant according any one of claims 1 to 16 received therein; inserting part of the delivery sleeve into the patient’s tissue at an insertion angle and deploying the electrode lead from within the delivery sleeve into the patient’s tissue; changing the orientation of the delivery sleeve with respect to the patient’s tissue thereby bending the flexible substrate to vary an angle between the electrode lead and the housing assembly received within the delivery sleeve; and deploying the housing assembly from within the delivery sleeve into the patient’s tissue at a deployment angle which is different to the insertion angle.

21. The method of claim 20, wherein prior to deploying the electrode lead from within the delivery sleeve into the patient’s tissue, the medical implant is arranged within the delivery sleeve such that a front end of the housing assembly from which the electrode lead extends isdirected oppositely to an opening of the delivery sleeve through which the electrode lead is deployed, and wherein the electrode lead overlies the housing assembly within the delivery sleeve and extends towards the opening.

22. A medical implant, for example a neurostimulator or diagnostic implant, comprising: a housing assembly comprising a tubular housing and an electronics assembly received at least partially within the tubular housing; and an electrode lead extending from the housing assembly and comprising one or more lead wires electrically connected to the electronics assembly, wherein the electrode lead comprises a helical portion.

23. The medical implant of claim 22, wherein the electrode lead comprises at least one electrode and the helical portion electrically connects the at least one electrode to the electronics assembly.

24. The medical implant of claim 22 or 23, wherein the electrode lead comprises a lead cover which houses the helical portion, optionally wherein the helical portion has a first diameter which is substantially constant along a length of the helical portion.

25. The medical implant of claim 24, wherein the helical portion is a first helical portion and the electrode lead comprises a second helical portion having a second diameter, greater than the first diameter, optionally wherein the second helical portion spirals around an outside of the first helical portion.

26. The medical implant of claim 25, wherein the first helical portion and / or second helical portion is operable as a wireless power antenna to supply power to the electronics assembly.

27. The medical implant of any one of claims 1-16 or 22-26, wherein the electrode lead is flexible.

28. A medical implant, for example a neurostimulator or diagnostic implant, comprising: a tubular housing, an electronics assembly housed within the tubular housing, an electrode lead extending from an end of the tubular housing, the electrode lead comprising one or more electrodes and one or more corresponding electrode wires, anda feedthrough arranged to seal the end of the tubular housing and having one or more connectors extending through the feedthrough to provide an electrical connection between the or each electrode wire and the electronics assembly within the tubular housing.

29. The medical implant of claim 28, wherein the feedthrough comprises a weld ring joined to the end of the tubular housing, and a body disposed within the weld ring.

30. The medical implant of claim 29, wherein the one or more electrode wires comprise the one or more connectors such that the electrode wires extend through the body and connect to the electronics assembly.

31. The medical implant of claim 29 or claim 30, wherein the body is a ceramic body.

32. The medical implant of any of claims 28 to 31, wherein the weld ring is a first weld ring, and the medical implant further comprises a second weld ring joined to the end of the tubular housing, and wherein the first weld ring and the second weld ring are welded together.

33. The medical implant of claim 32, wherein the tubular housing is ceramic and the second weld ring is brazed to the ceramic tubular housing.

34. A housing assembly for a medical implant, wherein the housing assembly comprises a tubular housing, an electronics assembly housed within the tubular housing, and a battery end cap attached to an end of the tubular housing, the battery end cap being configured to house one or more battery cells.

35. The housing assembly of claim 34, wherein the battery end cap comprises a tubular body having an open end, and wherein the open end is attached to an end of the tubular housing.

36. The housing assembly of claim 35, wherein an outer dimension of the battery end cap is the same as an outer dimension of the tubular housing.

37. The housing assembly of any of claims 34 to 36, wherein the battery end cap comprises a sealing plate arranged to seal the battery cells within the battery end cap.

38. The housing assembly of any of claims 34 to 37, comprising one or more terminals arranged to connect the one or more battery cells to the electronics assembly.

39. The housing assembly of claim 38, wherein the one or more terminals are configured to connect with a corresponding connector on the electronics assembly as the battery end cap is connected to the tubular housing.

40. The housing assembly of any of claims 34 to 39, wherein the battery end cap comprises an insulative material, for example a ceramic, and wherein the battery end cap is attached to the tubular housing by a weld ring.

41. A medical implant, for example a neurostimulator or diagnostic implant, comprising the housing assembly of any of claims 34 to 40.

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