Bone-anchored hearing aid assembly and kit

Abstract

A bone-anchored hearing aid assembly is provided comprising: an implantable anchoring shaft comprising an axial lumen extending therethrough and configured to be fixated within a burr hole drilled in the skull of a subject; and a removable stimulation unit shaped to be received within said axial lumen of the anchoring shaft; wherein the anchoring shaft and the stimulation unit are configured for detachable attachment of the stimulation unit to the anchoring shaft within said axial lumen of the anchoring shaft; and wherein said removable stimulation unit comprises a reciprocating end effector passing through a bottom aperture at a distal end of said removable stimulation unit, said end effector being configured and controllably actuated to perform a reciprocal movement along a main longitudinal axis of said removable stimulation unit for mechanically transmitting vibrations to a subj ect' s cochlear wall for perception by the subject as sound.

Description

[0001] BONE-ANCHORED HEARING AID ASSEMBLY AND KIT

[0002] TECHNOLOGICAL FIELD

[0003] The present disclosure relates generally to hearing aids, and more particularly, to a bone-anchored hearing assistance assembly.

[0004] BACKGROUND

[0005] Various implantable hearing devices have been developed to address different types and degrees of hearing impairment. These devices generally fall into three main categories: cochlear implants, middle ear implants, and bone-anchored hearing aids. Each of these technologies utilizes a unique approach to sound processing and transmission, targeting specific anatomical structures and hearing loss profiles.

[0006] Cochlear implants are designed for individuals with severe to profound sensorineural hearing loss, where the hair cells in the cochlea are damaged or absent. Unlike traditional hearing aids that amplify sound, cochlear implants bypass the damaged cochlea and directly stimulate the auditory nerve with electrical signals. A sound processor captures and converts sound into digital signals. These signals are transmitted to the implant that is an electrode array inserted into the cochlea, which then delivers electrical stimulation to the auditory nerve fibers.

[0007] Middle ear implants, on the other hand, are intended for individuals with mild to moderate sensorineural hearing loss or mixed hearing loss such as individuals which underwent radical mastoidectomy where the ossicles are removed. These devices work by converting sound into mechanical vibrations that are delivered directly to the ossicles in the middle ear. This approach amplifies sound and improves its transmission to the inner ear. Some middle ear implants are operating by vibrating the oval window membrane or the round window membrane, bypassing the ossicles. However, installation of most middle ear implant devices requires complex and delicate surgical procedures that limit their use. Further, active middle ear diseases preclude implantation of such implants in patients, and the subsequent development of middle ear infection in a patient with an existing implant can compromise device functionality and necessitate removal. Further, these implants are limited in achieving sufficient gain. WO 2014 / 030159, assigned to the assignee of the present application, describes a hearing aid device comprising: a deformable member configured for contracting and expanding along a deformation axis between its first and second sides in response to an applied external field; and a fastening assembly configured for carrying the deformable member to provide rigid coupling of the first and second sides of the deformable member to a bony tissue in the vicinity of cochlea, such that contraction and expansion of said deformable member directly stimulates vibration of the cochlear wall.

[0008] In the implantable middle ear hearing aid, which might need to be extracted or replaced, this opening the skull is typically sealed by repositioning the excised bone fragment and subsequently covering it with the scalp. Over time, the bone generally heals and reintegrates seamlessly and consequently an additional surgical intervention may be imperative for installing a new hearing aid. This could entail reopening the healed bone, akin to performing a subsequent craniotomy. The necessity for such a procedure is contingent upon the type of implant and the unique circumstances of the patient.

[0009] GENERAL DESCRIPTION

[0010] There is a need in the art for a novel approach in implantable hearing aid devices that allows easy and safe implant and removal of the hearing aid device from within the skull and reinstalling or replacing the device of one or more parts thereof when required, without additional skull drilling, while making the procedure less complex.

[0011] The present disclosure provides a bone-anchored hearing aid arrangement / assembly utilizing a permanent reusable cranial access port (termed herein below "anchoring shaft" or "external screw") in which the hearing aid (or at least a part thereof) incorporated within a removable stimulation unit (at times referred to herein below as "internal screw") can be reinstalled or replaced by a new one. For example, the reason for this can be that the end effector became too short, or the stimulation unit fails / malfunctions, or needs to be replaced by one with new design or actuator model. This configuration allows control on fine axial positioning of the implanted hearing aid device, e.g., adjusting axial positioning due to possible changes in the cochlear wall to skull distance, and for increasing or decreasing the force by which the removable stimulation unit, when installed in the anchoring shaft, pushes on the bone. It should be noted that the implant of the device of the present disclosure advantageously avoids any functional damage to the middle ear structure, and if required, can be easily removed while restoring the original middle ear functionality.

[0012] Upon removal of the hearing aid device from the access port (e.g., temporarily), the stimulation unit is replaced with an internal screw plug, and the access port can be covered by a scalp portion. The access port can then be readily accessible to the hearing aid device for reinstallation by simply removing or flapping over the scalp portion that covers the access port, and removing the plug screw, thus obviating the need for additional drilling after the initial procedure.

[0013] Thus, the bone-anchored hearing aid arrangement of the present disclosure combines durability, flexibility, and precision, offering a reliable solution for repeated skull access while preserving the structural integrity of the bone and surrounding tissue.

[0014] The bone-anchored hearing aid assembly (at times referred to herein as “assembly” for simplicity) includes a hollow anchoring shaft (constituting the reusable access port) adapted to be implanted within a burr hole drilled in the skull of the subject, and a removable / replaceable stimulation unit sized and shaped to be received within the hollow anchoring shaft and detachably attached thereto.

[0015] The stimulation unit is configured for directly stimulating the cochlear wall (i.e. the semicircular lateral canal part of the cochlea). To this end, the stimulation unit utilizes a reciprocating end effector controllably actuated for mechanically transmitting vibrations to the cochlear wall thereby causing movement of the perilymph fluid resulting in hearing sensation.

[0016] In the description below, the hollow anchoring shaft is at times referred to as "external screw". Also, in the description below, the stimulation unit detachably attachable to the inside of the hollow anchoring shaft is at times referred to as "internal screw". However, it should be noted that the principles of the present disclosure are not limited to this specific implementation of the hearing air assembly, and the detachable attachment between the hollow anchoring shaft and the stimulation unit located thereinside can utilize any suitable mechanism.

[0017] Thus, according to one broad aspect of the present disclosure, it provides a bone- anchored hearing aid assembly comprising: an implantable anchoring shaft comprising an axial lumen extending therethrough and configured to be fixated within a burr hole drilled in the skull of a subject; a removable stimulation unit shaped to be received within said axial lumen of the anchoring shaft; wherein the anchoring shaft and the stimulation unit are configured for detachable attachment of the stimulation unit to the anchoring shaft within said axial lumen of the anchoring shaft; and wherein said removable stimulation unit comprises a reciprocating end effector passing through a bottom aperture at a distal end of said removable stimulation unit, said end effector being configured and controllably actuated to perform a reciprocal movement along a main longitudinal axis of said removable stimulation unit for mechanically transmitting vibrations to a subject’s cochlear wall for perception by the subject as sound.

[0018] In some embodiments, the removable stimulation unit and the implantable anchoring shaft are configured such that, when the removable stimulation unit is received in the implantable anchoring shaft, a distal end portion of the removable stimulation unit projects out of a bottom surface of the implantable anchoring shaft.

[0019] In some embodiments, a lid cover can be provided being configured for sealing fitment with an opening on a top surface of the removable stimulation unit. Optionally, the lid cover can be configured with a pass-through bore serving as a working channel for passing or incorporating additional elements.

[0020] The lid cover can also have one or more recesses configured for receiving an input of an external tool for insertion of the removable stimulation unit within the implantable anchoring shaft (e.g., to a selected depth). The one or more recesses can define various geometries, e.g., cruciform, recessed hex.

[0021] In some embodiments, the removable stimulation unit includes at least one internal lumen-like cavity configured as a working channel for passing or incorporating additional elements. For example, the working channel may be used to insert an optical imaging device through it to visualize the insertion and adjustment procedure. The working channel(s) may be closed by respective screws or other plugs after the procedure is finished and reopened again when required.

[0022] Optionally, the lid cover can include a pass-through bore connected to the internal lumen-like cavity of the removable stimulation unit. For example, the working channel can be configured for passage of wires connecting to one or more microphones being located in the middle ear cavity. The one or more microphones may be inserted into the middle ear cavity, with the wires feeding through stimulation unit (via the working channel) to the outside electronics. The microphone / s may be used to sense the sound in the middle ear and also, to sense the user’s voice chord sounds and the blood pulse sound so they can be filtered out. The electronics can be located outside the skull, sub-dermally under the scalp or in a recces / socket formed in the bone and covered by the sculp.

[0023] The removable stimulation unit includes at least one actuator which is operatively coupled to the end effector for driving it to perform the reciprocal movement along the stimulation unit.

[0024] In some embodiments, the actuator may include or be configured as a piezoelectric element (e.g., piezo stack actuator , piezo bender actuator) or may include or be configured as an electromagnetic transducer. In some embodiments, the at least one actuator may be accommodated within the stimulation unit. For example, the removable stimulation unit comprises a first inner cavity for accommodating the at least one actuator thereinside and a channel extending between the first inner cavity and the bottom aperture such that the end effector performs the reciprocal movement along the channel to interact with a target intercranial surface, i.e., the cochlear wall via the bottom aperture in the stimulation unit. The actuator is accommodated in said first inner cavity between the end effector and a top surface of the stimulation unit (e.g., between the end effector and the lid cover).

[0025] In some other embodiments, the actuator (e.g., bender actuator) may be located externally to the assembly being installed in a socket properly formed in the skull bone in the vicinity of the burr hole. In such case, the channel extends between the top and bottom apertures. The bender actuator is coupled to the end effector via top aperture made in the stimulation unit, i.e., one end of the actuator is rigidly attached to the skull bone within the socket and the other end pushes against the end effector. In some embodiments, the external actuator may be accommodated within a housing located in the socket and extending towards the stimulation unit to be connected to the end effector. In operation, the bender actuator operates the end effector such that it exserts force (e.g., vibrations) through the end effector onto the target cochlear wall. A constant DC bias may be applied to the bender actuator for providing the optimal preload.

[0026] For example, the end effector can be in the form of a rigid rod coupled by its proximal end to the actuator and interact with the cochlear wall by its free opposite distal end.

[0027] In some embodiments, the anchoring shaft is made of one or more biocompatible and / or MRI compatible material compositions such as, but not limited to, titanium alloy, platinum, platinum alloy, or polymers such as PEEK. The diameter of the anchoring shaft can be slightly smaller than that of the burr hole for allowing the anchoring shaft to be advanced into and adhered to the burr hole. Optionally, the hollow anchoring shaft may have threads on its outer / external circumferential surface for screwing the hollow anchoring shaft into the burr hole. The external threads may be external threads may be treated to have a surface finish that will enable bone attachment to the anchoring shaft and encourage osseointegration with the skull bone, ensuring a stable and secure fit. In such case, the diameter of the burr hole can be slightly smaller than the diameter of the anchoring shaft for screwing the anchoring shaft into the burr hole.

[0028] The removable stimulation unit includes on its outer surface at least one fitting feature configured for matingly engaging with at least one counterpart mating feature on an inner surface of the implantable anchoring shaft such that the fitting features forming the detachable attachment.

[0029] The detachable attachment of the stimulation unit to the anchoring shaft the can, in some embodiments, be via threaded engagement therebetween. To this end, the anchoring shaft has a threaded section on its inner circumferential surface and the stimulation unit has a counterpart threaded section on its outer circumferential surface. In possible embodiment, the inner threads of the anchoring shaft as well as the external threads of the stimulation unit may be treated such as to reduce friction and the stress on the external threads of the anchoring shaft when the stimulation unit is being screwed into the anchoring shaft

[0030] The external surfaces of the screws stimulation unit as well as those of the end effector may be treated with a coating, e.g., SiN or Diamond-like carbon (DLC) coating, that inhibits tissue adherence to it. Keeping in mind that after implantation, the bony tissue may regrow to close the bores, the coating makes it possible for the end effector to move axially (reciprocal movement / displacement) and for the entire stimulation unit to be removed or replaced.

[0031] The terms “top, upper and proximal” and “botom, lower and distal” as well as are used throughout this disclosure to denote relative position and / or orientation of different features and / or surfaces of the assembly with respect to inner ear of the subject. In particular, the term top, upper and proximal denotes location(s) closer to the scalp of the subject’s head, and the term “bottom, lower and distal” is used herein to denote location(s) closer to the inner ear of the subject. The stimulation unit may be provided with a flexible member configured and arranged for maintaining the end effector on the movement axis (i.e., along the stimulation unit) while performing the reciprocal movement. Generally, the flexible member is fixedly attached to the stimulation unit and appropriately coupled to a circumference of a portion of the end effector in a fluid-tight manner such that the end effector protrudes the flexible member. This way the reciprocal movement of the end effector is allowed due to flexibility of the flexible member. Such fluid-tight coupling / attachment of the flexible member to the stimulation unit and to the end effector, while allowing the required reciprocal movement of the end effector, prevents passage of fluids from the inside of the skull into the stimulation unit.

[0032] In some embodiments, the removable stimulation unit comprises a cavity (at times called "second cavity"), and the flexible member is fixedly coupled (e.g., by its perimeter) to at least one surface defined by said cavity. For example, such flexible member can include or be in the form of a diaphragm. As will be described more specifically further below, such flexible member has a dome-like configuration or is corrugated and / or stretchable.

[0033] In case the stimulation unit uses the inner actuator, the end effector extends / moves along a channel extending between the first inner cavity and the second inner cavity. In case the stimulation unit uses the externally located actuator, the end effector moves along a channel extending between the top aperture and the second inner cavity.

[0034] In some embodiments, the flexible member is configured as an O-ring positioned within the bottom portion of the removable stimulation unit.

[0035] In some embodiments, the flexible member is configured as a flexible polymer membrane attached to an external surface of the stimulation unit around the bottom aperture thereof.

[0036] As noted above, in some embodiments, the surface of the end effector as well as the one or more surfaces of the lid cover can be coated, e.g., with SiN or Diamond-like carbon (DLC), so as to minimize or inhibit tissue from adhering thereto and allow free movement of the end effector if tissue grows around it.

[0037] In some embodiments, a spring can be used being mounted in the stimulation unit such that the axis of spring's contraction / expansion extends along the actuation / movement axis of the end effector to compensate for skull to cochlea distance due to skull growth or distortion. The latter may occur over age or due to force applied during operation of the assembly. The spring may be connected by one end thereof to the lid cover sealingly fitted (e.g., by threading) in the top aperture of the stimulation unit or may just be stopped by the lid cover at the proximal side of the spring, and by its opposite end, the spring may be connected to the actuator or just interact with the actuator. In other words, the spring is at its opposite end enclosed between the lid cover and actuator. For example, considering the use of piezo-element in the actuator, when the actuator is expanding or contracting along the actuation axis, the end effector applies force onto the target cochlear wall. Compensation for skull to cochlea distance due to skull growth or distortion may also be achieved by attaching the end of the spring to the lid cover by the screwing the lid cover while keeping the required force onto the target cochlear wall.

[0038] In some embodiments, an upper surface of the implantable anchoring shaft comprises a plurality of spaced-apart openings configured for receiving an input of an external tool for insertion of the implantable anchoring shaft within the burr hole drilled in the skull of the subject.

[0039] In some embodiments, a top surface of the removable stimulation unit comprises one or more recesses configured for receiving an input of an external tool for insertion of the removable stimulation unit to a selected depth within the implantable anchoring shaft.

[0040] One or more electric circuitries / modules may be located externally to the assembly configured to establish signal communication the stimulation unit, wirelessly and / or over subdermal conducting wires (not shown) passing through one or more openings of the stimulation unit. The electric circuitries may be accommodated within a socket / recces formed in the skull bone or mastoid part of the temporal bone if it’s too bulky. The electric circuitries may be used to record data and relay signals to the stimulation unit (as well as relay signals from the microphone(s) if used), and may also be used to send or receive data / signals to / from the external devices via RF and / or optical and / or acoustic means. Connection of the subdermal electric circuitries to the stimulation unit, may be carried out using a pre-wired option. The electric circuitries and the stimulation unit can be pre- wired together or connected through a suitable connector of the sub dermal electric circuitries. For example, such electric circuitries may include or be connected to a power source such as a rechargeable battery with RF means for charging it from outside the body of the subject. In some embodiments, the anchoring shaft comprises a central cavity and configured for receiving within said cavity an angular displacement unit configured for performing angular displacement with respect to the implantable anchoring shaft.

[0041] In some embodiments, the axial lumen is formed in the angular displacement unit, said central cavity having an internal circumferential concavely curved surface facing a substantially matching external circumferential convexly curved surface of the angular displacement unit when angular displacement unit is received in the implantable anchoring shaft, thereby enabling adjustable orientation of the angular displacement unit relative to the anchoring shaft.

[0042] The implantable anchoring and / or the implantable anchoring shaft has a fixation mechanism configured for affixing the angular displacement unit at a coaxial position with respect to the implantable anchoring shaft, in which a main longitudinal axis of the implantable anchoring shaft coincides with a main longitudinal axis of the angular displacement unit.

[0043] For example, the angular displacement unit can have a bore extending between its upper surface and its convexly curved surface, and the implantable anchoring shaft can have a respective bore extending from its concavely curved surface. The bores are being aligned in the coaxial position and configured to receive a locking member therewithin to thereby lock the angular displacement unit and the implantable anchoring shaft in the coaxial position. It should however be noted that the present disclosure is not limited to this type of locking mechanism and that other mechanisms may be used to lock the angular displacement unit and the implantable anchoring shaft in the coaxial position.

[0044] The anchoring shaft can have a peripheral lip / flange extending laterally from the hollow shaft (e.g., from its top circumferential edge). The peripheral lip may be adhered to the skull bone and / or may have a plurality of holes configured for receiving screws to be screwed into the skull for securing the anchoring shaft to the skull bone. The stimulation unit and or the anchoring shaft may have a surface cover / layer that is made from material preventing tissue adhesion to facilitate easy removal of the tissue for allowing access to the stimulation unit. The location and orientation of the burr hole to be drilled may be determined by using CT or other imaging techniques. The drilling of the burr hole may be performed by using prefabricated jigs after analyzing the location and orientation data as known in the art. This data can further be used for inserting the stimulation unit to a predetermined depth within the anchoring shaft, such that the end effector reaches the target site (i.e., cochlear wall) and exerts the required force.

[0045] According to another one broad aspect of the present disclosure, it provides a removable stimulation unit for use in a bone-anchored hearing aid assembly, said removable stimulation unit being configured for detachable attachment within an axial lumen of an implantable anchoring shaft, when mounted within a burr hole drilled in the skull of a subject, wherein said removable stimulation unit has a bottom aperture at a distal end thereof and comprises at least one actuator and a reciprocating end effector passing through said bottom aperture, said end effector being configured to perform a reciprocal movement along a main longitudinal axis of said removable stimulation unit for mechanically transmitting vibrations to a subject’s cochlear wall for perception by the subject as sound, and said at least one actuator being operatively coupled to said end effector for driving it to perform the reciprocal movement

[0046] According to another one broad aspect of the present disclosure, it provides a kit for use in assembling an implantable hearing aid for mechanically transmitting vibrations to a subject’s cochlear, the kit comprising: a number N (N>1) of removable stimulation units, each configured as described above for detachable attachment to a predetermined anchoring shaft implanted in a burr hole in the skull of a subject; and one or more tools for insertion of the removable stimulation unit to a selected depth within the implantable anchoring shaft.

[0047] In some embodiments, the kit further includes one or more elements to be located within at least one working channel made in the removable stimulation unit.

[0048] In some embodiments, the kit further includes at least one microphone to be installed, in the middle ear cavity. The microphone(s), if is / are to be used, is / are installed through the lumen / bore of the stimulation unit before the insertion of the stimulation unit, while the wires pass through a working channel in the stimulation unit. The bore in this case is larger as to accommodate the wires and the end effector.

[0049] According to another one broad aspect of the present disclosure, it provides kit for use in assembling an implantable hearing aid for mechanically transmitting vibrations to a subject’s cochlear, the kit comprising: a number N (N>1) of anchoring shafts, each configured for implantation in a burr hole in the skull of a subject, a number M (M>1) of removable stimulation units, each removable stimulation unit being configured as described above for detachable attachment to a selected anchoring shaft upon implantation of said anchoring shaft in the burr hole in the skull; one or more tools for insertion of the implantable anchoring shaft within the burr hole drilled in the skull of the subject; and one or more tools for insertion of the removable stimulation unit to a selected depth within the implantable anchoring shaft.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0052] Figs. 1A to 1C are schematic illustrations of a bone-anchored hearing aid assembly of the present disclosure, wherein, Fig. 1A is a cross-sectional view of the assembly, Fig. IB is a side perspective view of the assembly, and Fig. 1C is a top-side perspective view of the assembly;

[0053] Fig- 2 is a cross-sectional view of a non-limiting configuration of a bone-anchored hearing aid assembly with an anchoring shaft having external thread;

[0054] Fig. 3 schematically illustrates top view of specific non-limiting examples of the configuration of the bone-anchored hearing aid assembly;

[0055] Fig. 4 schematically illustrates bottom view of specific non-limiting examples of the bone-anchored hearing aid assembly of the present disclosure;

[0056] Figs. 5A to 5C schematically illustrate specific non-limiting examples of the configurations of the bone-anchored hearing aid assembly with its actuator, wherein Fig. 5A exemplifies the assembly with an inner actuator, and Figs. 5B and 5C exemplify the assembly with an externally located bender type actuator;

[0057] Figs. 6A to 6C schematically illustrate, respectively, a cross-sectional view, topperspective view and a perspective view with some exploded parts of the specific nonlimiting example of the configuration of the assembly incorporating a cover lid and a spring;

[0058] Figs. 7A to 7C schematically illustrate cross-sectional views of specific nonlimiting examples of the configuration of the bone-anchored hearing aid assembly incorporating a flexible member, wherein Fig. 7A shows the assembly with a diaphragm, and Figs. 7B and 7C show two examples of the assembly with an O-ring; Figs. 8A to 8D, schematically illustrate different views of specific non-limiting examples of the configuration of the bone-anchored hearing aid assembly with an angular adjustment unit; and

[0059] Fig. 9 is a flow diagram of an exemplary method for implanting / installing the assembly.

[0060] DETAILED DESCRIPTION

[0061] Reference is made to Figs. 1A-1C, which schematically illustrate a cross-sectional view, side perspective view, and top-side perspective view, respectively, of a bone- anchored hearing aid assembly, generally designated 10, in its assembled state, according to some embodiments of the present disclosure. As shown, assembly 10 includes an implantable anchoring shaft 12 configured to be fixated within a burr hole drilled in the skull of a subject, and a stimulation unit 14 shaped and sized to be received and mounted within the anchoring shaft 12. The assembly 10 is configured and operable to apply vibrations to a cochlea wall CW of subject's cochlea C for perception by the subject as sound.

[0062] The anchoring shaft 12 has a top opening 12t at a proximal end of the shaft 12, a bottom opening 12b at a distal end of the shaft 12, and an axial lumen 12x extending between the top and bottom opening along the length of the anchoring shaft 12. The stimulation unit 14 is received and mounted within the lumen 12x such that the stimulation unit 14 is detachably attached to the anchoring shaft 12 along its axial lumen.

[0063] In the non-limiting example of Fig. 1A, the attachment of the stimulation unit 14 to the anchoring shaft 12 is through screwing / threading mechanism. As shown, the anchoring shaft 12 has threads 12h arranged along its inner circumferential surface, along the lumen, and the stimulation unit 14 has threads 14h arranged along the length of its outer circumferential surface and configured to threadably engage with the threads 12h to form tight attachment of the stimulation unit 14 to the anchoring shaft 12 along its axial lumen and allowing detachment when needed. Thus, in this example, the anchoring shaft 12 and the stimulation unit 14 are configured as, respectively, outer and inner screws.

[0064] The stimulation unit 14 is formed with a longitudinal inner channel (cavity) 14a and is formed with a bottom aperture 14b located at a distal end of the channel 14a. The stimulation unit 14 includes a reciprocating end effector 14e (typically in the form of an elongated rod) installed in said channel 14a. The end effector 14e is controllably actuated to perform a reciprocal movement (e.g., in a range of 40-100nm), designated by arrow D, along an axis O of the channel (and thus of the removable stimulation unit 14) allowing the end effector, by its distal end, to pass through the bottom aperture 14b for mechanically transmitting vibrations to the cochlea wall CW for perception by the subject as sound. The end effector 14e by its opposite proximal end is attached to an actuator, as will be described further below, which actuates and controls the movement of the end effector.

[0065] The anchoring shaft 12 can be secured within the burr hole, for example by adhesion of its external surface 12e ( / '.<?., its perimeter / circumference) to the burr hole. In some embodiments, the anchoring shaft 12 includes a circumferential top lip 12i configured for tight attachment of the anchoring shaft 12, while in the burr hole, to the skull bone for securing the anchoring shaft 12 within the burr hole. The circumferential top lip 12i can be attached to the skull bone (not shown) for example by adhesion. Alternatively or additionally, the circumferential top lip 12i can be formed with a plurality of spaced-apart openings 12g configured for receiving screws or bolts or the like tools for attaching the anchoring shaft 12 to the skull bone.

[0066] In order to facilitate illustration and understanding, the same reference numbers are used to indicate functional components that are common in all the examples of the present disclosure.

[0067] Fig. 2 schematically illustrates cross-sectional view of a specific non-limiting example of the bone-anchored hearing aid assembly 10 of the present disclosure. In this example, the assembly is configured generally similar to that of Figs. 1A-1C, and Fig. 2 exemplifies that the anchoring shaft 12 has threads 12h arranged along the length of its outer circumferential surface enabling threadable engagement of the threads 12h with corresponding / counterpart threads (not shown) which may be formed in the burr hole in the bone.

[0068] Reference is made to Fig. 3, schematically illustrating top view of specific nonlimiting example of the configurations of the bone-anchored hearing aid assembly 10 of the present disclosure. In these figures, assembly 10 is shown when it is implanted / installed in the burr drilled in the skull S of the subject. As shown, the anchoring shaft 12 can have at least one but practically a plurality of openings 12p formed on its top surface 12s - four such openings 12p e.g., in a radially symmetrical fashion, being exemplified in these figures. The opening 12p is configured for receiving an input of an external tool (e.g., a 4-pin wrench) for insertion of the anchoring shaft 12 within the drilled burr hole.

[0069] As mentioned above, the anchoring shaft 12 can have threads (12h in Fig. 2) arranged along length of its outer circumferential surface. This way, the anchoring shaft 12 can be used, when it is connected to a 4-pin wrench via openings 12p, to drill the burr hole in the skull such that the threads 12h (Fig. 2) form corresponding threads in the burr hole upon drilling. Alternatively, the threads in the burr hole can be formed, by a suitable tool, prior to insertion of the anchoring shaft 12 such that the anchoring shaft 12 can be screwed into the burr hole by using the 4-pin wrench.

[0070] In this example, the stimulation unit 14 has one or more recesses 14r formed on its top surface 14s and configured for receiving an input of an external tool for insertion of the stimulation unit 14 to a selected depth within the implantable anchoring shaft 12. In this example, the stimulation unit 14 has a cruciform recess.

[0071] Reference is made to Fig. 4 schematically illustrating bottom views of a specific non-limiting example of the bone-anchored hearing aid assembly 10 of the present disclosure.

[0072] In this example, the assembly 10 is shown as being implanted / installed in the burr drilled in the skull S of the subject and showing a bottom / distal portion 14p of the stimulation unit 14 projecting out of the bottom opening (not seen here) of the anchoring shaft 12.

[0073] Referring to Figs. 5A-5C, there are schematically illustrated cross-sectional views of specific non-limiting examples of the configuration of the assembly 10 of the present disclosure. These figures illustrate more specifically possible accommodations of an actuator for controllable operation of the reciprocal movement of the end effector.

[0074] In the example of Fig. 5A, the stimulation unit 14 has an inner cavity 14c (which for the purposes of further examples is termed herein "first inner cavity") and the inner channel 14a, containing the end effector, extends between the first inner cavity 14c and the bottom aperture 14b. An actuator 14u (e.g., a piezoelectric or electromagnetic actuator) is accommodated within the first inner cavity 14c and is operatively coupled to the end effector 14e. The end effector 14e by its proximal end is coupled to the actuator 14u, which is controllably axially deformable, thereby causing reciprocal axial movement of the end effector in the channel 14a in accordance with a predetermined movement pattern. This results in a corresponding pattern of the end effector projection through the bottom aperture 14b towards and on the cochlea wall, providing a desired pattern of the interaction force of the end effector with the cochlea wall. This arrangement provides the mechanically transmitted vibrations to the cochlear wall CW, which causes the cochlear wall to deform and push the perilymph.

[0075] Figs. 5B and 5C exemplify a configuration of the assembly 10 which utilizes a piezo bender actuator assembly 14u’ including a bender actuator 16p which is operatively coupled to an electronic circuitry 16v located externally to the assembly 10 (located within a socket 16’ that can be formed in the skull S externally (e.g., in vicinity) to the assembly 10), and is also connected to the proximal end / portion of the end effector 14e. As seen in Fig. 5B, the stimulation unit 14 has the inner channel 14a extending between a top opening 14t (although not seen in the figure since the actuator is shown as being installed therein) located on the top surface 14s of the stimulation unit 14 and the bottom aperture 14b. The end effector 14e extends along the channel 14a and its proximal end is connected to the actuator via a top aperture 14t of the top surface of the stimulation unit 14. In the example of Fig. 5B, the bender actuator 16p is anchored by its one end to the electronic circuitry 16v and on the other side / end is free to move so as to press against the end effector 14e. Alternatively, the bender actuator 16p can be anchored by its one end to the skull bone while being electrically coupled to the electronic circuitry 16v (e.g., by conducting wires), and on the other side / end is free to move so as to press against the end effector 14e.

[0076] Thus, in these configurations the end effector, by its proximal end, slightly projects out of the stimulation unit via the top aperture. In operation, the bender actuator 16p moves the end effector 14e reciprocally in response to a voltage applied to the bender actuator 16p by the electronic circuitry 16v.

[0077] As also exemplified in the figure, one or more recesses 14k may be formed on the top surface 14s of the stimulation unit 14 being configured for receiving an input of an external tool for insertion of the removable stimulation 14 unit to a selected depth within the anchoring shaft 12.

[0078] It should also be noted and is exemplified in Fig. 5A that, in some embodiments, internal lumen-like cavity(ies) 14w can be formed in the stimulation unit 14 therealong to serve as working channel(s) for passing therethrough additional elements / utilities. For example, such working channel(s) may be used for advancing conducting wires of one or more microphones into the middle ear. Referring to Figs. 6A to 6C, there are schematically illustrated a cross-sectional view (Fig. 6A), top perspective view (Fig. 6B) and a perspective view (Fig. 6C) with some exploded parts of an exemplary assembly 10. In this example, the stimulation unit 14, which is configured generally similar to the above-described examples with the inner actuator, has a removable cover lid 141 configured for sealing fitment with the top opening (seen as 14t in Fig. 6C) of the stimulation unit 14. For example, such sealing fitment can be implemented by threading / screwing of the cover lid 141 in the top opening 14t.

[0079] Also provided in the stimulation unit 14 is a spring member 14n located in the first inner cavity 14c and arranged / accommodated such that it is, at its opposite ends, enclosed between the cover lid 141 and the actuator 14u. The spring member 14n may by its one end be coupled to or just be in contact with the cover lid 141 and by its opposite end be connected to or just be in contact with the actuator 14u. The spring member 14n may be used to adjust preload force of the actuator or further compensate for natural skull to cochlea distance change by maintaining efficient force on the target surface (i.e., cochlear wall) being transferred via end effector 14e.

[0080] It should, however, be noted (although not specifically shown) that the stimulation unit 14 may be provided with such a cover lid 141 irrespectively of whether the spring mechanism is used or not. The cover lid 141 may be inserted to a selected depth within the first inner cavity 14c and / or may have a selected width to adjust preload force on the actuator 14u, for maintaining efficient force on the target surface and compensate for natural skull to cochlea distance change by changing the insertion depth.

[0081] As shown in Figs. 6B and 6C, the cover lid 141 is formed with an inner hollow working channel, whose proximal end is shown as an opening 14g on the top surface 14z of the cover lid 141. Generally, the cover lid 141 can be formed with more than one such working channel. The working channel can for example serve for passage of subdermal conducting wires or tubes to the bottom side of scalp or through the scalp.

[0082] Optionally, as also shown in Fig. 6B, a socket 16 can be formed in the skull S being external to assembly 10, e.g. in the vicinity thereof. The socket 16 can be adapted for housing therein electric circuitries / modules (e.g. , power source) that may be in signal communication with the assembly 10, namely with its stimulation unit 14. Such signal communication can be wireless and / or over subdermal conducting wires passing through opening 14g in the stimulation unit 14. The electric circuitries may be used to record data and relay data / signals to the stimulation unit 14. They may also be used to send or receive data from external devices via RF and / or optical and / or acoustic means; as well as can include power source and the circuitry to charge it.

[0083] Reference is made to Figs. 7A and 7B, schematically illustrating cross-sectional views of specific non-limiting configurations of the bone-anchored hearing aid assembly 10 according to further non-limiting examples. In these examples, the stimulation unit 14 further includes a flexible member for maintaining the end effector while on its movement axis while performing the reciprocal movement thereof. The flexible member, while being fixedly attached to the stimulation unit in a fluid tight-manner, coupled to a circumference of the end effector 14e such that the end effector protrudes the flexible member. The reciprocal movement of the end effector 14e is allowed due to the flexibility of the flexible member in the axial direction. The flexible member can be made of any suitable biocompatible and MRI compatible material such as metal alloys or polymers.

[0084] In these examples, the stimulation unit 14 has a second inner cavity 14m extending from the bottom surface 14f of the stimulation unit 14. Mor specifically, the inner channel (containing the end effector) is formed with a symmetrical protrusion in a portion thereof forming said second inner cavity.

[0085] In the example of Fig. 7A, the flexible member is in the form of a generally domeshaped diaphragm 14d located within said second inner cavity 14m such that the diaphragm is connected by its perimeter to the bottom surface 14f of the second inner cavity 14m while by its inner surface surrounds and connected to the end effector in a fluid-tight manner. The end effector 14e thus extends into the second inner cavity 14m to protrude the diaphragm 14d such that the diaphragm 14d allows the end effector 14e to perform the reciprocal movement. It should, however, be noted that the diaphragm 14d may be of any shape, for example curved or corrugated etc.

[0086] In case the actuator 14u is located within the first inner cavity 14c, the end effector 14e passes along the channel 14a extending between the first inner cavity 14c and the second inner cavity 14m. In case the stimulation unit uses the externally located actuator (14u’ in Fig. 5B), the channel 14a extends between the top aperture and the second inner cavity.

[0087] In the example of Fig. 7B, the flexible member is in the form of a ring-like flexible member 14d” (O-ring). Such O-ring is positioned within a grove / cavity 14m' created in a distal side of the channel 14a, such that the ring-like flexible member 14d” is abutted / pressed against a perimetric side wall of the groove 14m' and against the end effector 14e in a fluid-tight manner.

[0088] In the example of Fig. 7C, the flexible member is in the form of a ring-like flexible member 14d” (O-ring). Such O-ring is positioned within a grove / cavity 14m' created on the bottom surface 14f of the stimulation unit, such that the ring-like flexible member 14d” is abutted / pressed between the side wall of the groove 14m' and against the end effector 14e in a fluid-tight manner.

[0089] Reference is made to Figs. 8A to 8C, schematically illustrating different views of specific non-limiting examples of the configurations of the bone-anchored hearing aid assembly 10. In these examples, the anchoring shaft 12 has a central cavity 12c with an internal circumferential concavely curved surface 12v extending between the top and bottom openings 12t and 12b of the anchoring shaft. The assembly 10 has a generally hemispherical shaped angular displacement unit 20 including the axial lumen 12x. The angular displacement unit 20 is configured to be received and installed within the central cavity 12c of the anchoring shaft 12 and has external circumferential convexly curved surface 20s that matches the internal circumferential concavely curved surface 12v of the anchoring shaft 12. This way, adjustment of the orientation of the angular adjustment unit 20 relative to the anchoring shaft 12 can be provided.

[0090] In particular, the angular displacement unit 20 is movable (e.g., slidably) within the central cavity 12c between a coaxial position of the unit 20, in which its main longitudinal axis Oi coincides with the main longitudinal axis O of the anchoring shaft 12, and an angular / slanted position of the unit 20, in which its main longitudinal axis Oi defines an angle (it tilted) with respect to the main longitudinal axis O of the anchoring shaft 12.

[0091] As shown in Fig. 8A, the angular displacement unit 20 has a pass-through bore 20p extending between its upper surface 20u and its convexly curved surface 20s, and the anchoring shaft 12 has an inner bore 12n extending from its concavely curved surface 12v. In the coaxial position of the angular displacement unit 20, the pass-through bore 20p and the inner bore 12n are aligned and can therefore receive a locking member 22, such as a pin, bolt or screw, which when inserted in both aligned bores, locks the angular adjustment unit 20 in its coaxial position.

[0092] As also exemplified in Fig. Fig. 8A, the angular displacement unit 20 is configured to receive a hollow delivery unit 24 within the axial lumen 12x such that the hollow delivery unit 24 is detachably attachable to the angular displacement unit 20 along its axial lumen 12x. In this non-limiting example, the attachment is thread-based, namely the delivery unit 24 has threads 24h on its outer surface configured for threadable engagement with internal threads 20h of the angular adjustment unit 20. The delivery unit 24 is configured to allow insertion of additional elements / utilities such as a cochlear implant or an endoscope into the middle ear.

[0093] Thereafter, the delivery unit 24 can be removed from the axial lumen 12x of the angular displacement unit 20 and the locking member 22 can be inserted to the pass- through bore 20p and the inner bore 12n to lock the angular displacement unit 20 in its co-axial position, as shown in Fig. 8B. Then, the stimulation unit 14 can be inserted into the axial lumen 12x.

[0094] As exemplified in Fig. Fig. 8B, the stimulation unit 14 can include a removable cover lid 141’ having a pass-through bore 26 configured as a working channel for passing or incorporating additional elements (e.g., passing of subdermal wires).

[0095] Fig. 9 is a flow diagram, illustrating in a self-explanatory manner, an exemplary method 100 for implanting / installing the assembly 10. To this end, location data about the target surface inside the cranium for the implantation of the assembly, as well as data about the exact location, orientation and size of the burr hole for the implantation of the anchoring haft, are provided. This data is used to generate a 3D model of the skull and the target location and orientation of burr hole and the distance of the target surface from the surface of the skull.

[0096] Then, a guide jig that that can be attached to the skull is used. The guide jig can be constructed by 3D printing based on the 3D model providing guide for boring tools. This way, the jig enables accurate location, orientation and depth of the bores and later the anchoring shaft and the stimulation unit to position the end effector exactly on the target surface, i.e., cochlear wall.

[0097] Then, boring tools are selected to drill the burr hole for the anchoring shaft and the stimulation unit (end effector). Cutting and flipping over the scalp is performed over the areas for the burr hole, and, if required, over a location for placement of the subdermal electric circuitries / modules. Then, a socket is formed in the skull bone for placement of the subdermal circuitries / modules.

[0098] The generated 3D model is used to align and attach the guide jig to the skull. The guide jig and boring tool are used to drill the burr hole in the temporal bone in the right orientation, deep enough to receive the anchoring shaft and the stimulation unit. The same guide and another smaller diameter boring tool are used to cut a path through the bone for the end effector and optional microphone wires, deep enough to reach the middle ear cavity. The anchoring shaft tool is used to insert the anchoring shaft into the burr hole in the temporal bone to a predetermined depth. Then, the anchoring shaft is locked / anchored to the skull bone. The stimulation unit, with its components, is inserted into the anchoring shaft with the end effector passing in first into the anchoring shaft; and fitting tools are used to screw the stimulation unit into its predetermined depth as for said end effector to apply the required force on the cochlear wall. If an acoustic transducer is used, it may be inserted into the middle ear cavity prior to insertion of the stimulation unit.

[0099] Then, Auditory Brainstem Response (ABR) can be used to test the performance of the device when operated with an external signal source and adjust the force if required. Temporary plugs can be used to seal the wire holes in the stimulation unit. The subdermal electronics can be placed / attached into their position. The flipped scalp can be finally re-applied onto the implants.

Claims

CLAIMS:

1. A bone-anchored hearing aid assembly comprising: an implantable anchoring shaft comprising an axial lumen extending therethrough and configured to be fixated within a burr hole drilled in the skull of a subject; a removable stimulation unit shaped to be received within said axial lumen of the anchoring shaft; wherein the anchoring shaft and the stimulation unit are configured for detachable attachment of the stimulation unit to the anchoring shaft within said axial lumen of the anchoring shaft; and wherein said removable stimulation unit comprises a reciprocating end effector passing through a bottom aperture at a distal end of said removable stimulation unit, said end effector being configured and controllably actuated to perform a reciprocal movement along a main longitudinal axis of said removable stimulation unit for mechanically transmitting vibrations to a subject’s cochlear wall for perception by the subject as sound.

2. The assembly of claim 1, wherein the removable stimulation unit further comprises at least one actuator which is operatively coupled to said end effector for driving it to perform the reciprocal movement.

3. The assembly of claim 2, wherein the removable stimulation unit comprises a first inner cavity for accommodating the at least one actuator thereinside.

4. The assembly of claim 3, wherein the removable stimulation unit comprises a channel formed therein extending between the bottom aperture and the inner cavity, such that the end effector performs said reciprocal movement along said channel.

5. The assembly of any one of claims 2 to 4, further comprising a lid cover configured for sealing fitment with an opening on a top surface of the removable stimulation unit.

6. The assembly of claim 5, wherein said lid cover comprises a pass-through bore serving as a working channel for passing or incorporating additional elements.

7. The assembly of claim 5, further comprising a lid cover configured for sealing fitment with an opening on a top surface of the removable stimulation unit, wherein said lid cover comprises a pass-through bore connected to said internal lumen-like cavity serving as a common working channel for passing or incorporating additional elements.

8. The assembly of any one of claims 6 or 7, wherein the working channel is configured for passage of electric wires for connecting to one or more microphones being located in the inner ear cavity.

9. The assembly of any one of claims 5 to 8, wherein said lid cover comprises one or more recesses configured for receiving an input of an external tool for insertion of the removable stimulation unit within the implantable anchoring shaft.

10. The assembly of any one of claims 5 to 9, wherein the removable stimulation unit further comprises a spring member arranged such that it extends and is enclosed between the lid cover and the at least one actuator.

11. The assembly of claim 1, further comprising at least one actuator located externally to the removable stimulation unit and operatively coupled to said end effector for driving it to perform the reciprocal movement.

12. The assembly of claim 11, wherein the removable stimulation unit comprises a top aperture and wherein the end effector passes through said top aperture.

13. The assembly of claim 12, wherein the removable stimulation comprises a channel extending between the top aperture and the bottom aperture such that the end effector performs said reciprocal movement along said channel.

14. The assembly of any one of the claims 1 to 13, wherein the stimulation unit comprises a flexible member fixedly mounted within the stimulation unit and in fluid- tight engagement with a circumference of a portion of the end effector thereby maintaining the end effector on its reciprocation axis while allowing the reciprocal movement of the end effector due to flexibility of the flexible member.

15. The assembly of claim 14, wherein the removable stimulation unit comprises a second cavity, and the flexible member is fixedly mounted within said second cavity.

16. The assembly of claim 15, wherein the flexible member is fixedly attached to at least one surface defined by said second cavity and coupled to the circumference of the portion of the end effector in a fluid-tight manner such that the end effector protrudes the flexible member17. The assembly of claim 16, wherein the flexible member is configured as a diaphragm fixedly coupled to at least one surface defined by said second cavity.

18. The assembly of claim 17, wherein the diaphragm has at least one of a domeshaped, corrugated and stretchable configurations.

19. The assembly of claim 15, wherein the flexible member is configured as an O- ring pressed between the end effector and inner perimetric side wall of the second cavity.

20. The assembly of any one of claims 1 to 19, wherein the removable stimulation unit and the implantable anchoring shaft are configured such that, when the removable stimulation unit is received in the implantable anchoring shaft, a distal end portion of the removable stimulation unit projects out of a bottom surface of the implantable anchoring shaft.

21. The assembly of any one of claims 1 to 20, wherein the reciprocating end effector is in the form of a rod coupled by its proximal end to the at least one actuator and configured for interaction with the cochlear wall by its free opposite distal end, to thereby provide said mechanically transmitting vibrations to the cochlear wall.

22. The assembly of any one of claims 1 to 21, wherein an outer surface of the removable stimulation unit and an inner surface of the implantable anchoring shaft comprise threads configured for threaded engagement between them.

23. The assembly of any one of claims 1 to 22, wherein an upper surface of the implantable anchoring shaft comprises a plurality of spaced-apart recesses configured for receiving an input of an external tool for insertion of the implantable anchoring shaft within the burr hole drilled in the skull of the subject.

24. The assembly of any one of claims 1 to 23, wherein a top surface of the removable stimulation unit comprises one or more recesses configured for receiving an input of an external tool for insertion of the removable stimulation unit to a selected depth within the implantable anchoring shaft.

25. The assembly of any one of claims 1 to 24, wherein the removable stimulation unit further comprises at least one internal hollow channel configured as a working channel for passing or incorporating additional elements.

26. The assembly of any one of claims 1 to 25, wherein the anchoring shaft comprises a central cavity and configured for receiving within said cavity an angular displacement unit configured for performing angular displacement with respect to the implantable anchoring shaft.

27. The assembly of claim 26, wherein the axial lumen is formed in the angular displacement unit, said central cavity having an internal circumferential concavely curved surface facing a substantially matching external circumferential convexly curved surface of the angular displacement unit when angular displacement unit is received in theimplantable anchoring shaft, thereby enabling adjustable orientation of the angular displacement unit relative to the anchoring shaft.

28. The assembly of claim 26 or 27, wherein the implantable anchoring and / or the implantable anchoring shaft comprises a fixation mechanism configured for affixing the angular displacement unit at a coaxial position with respect to the implantable anchoring shaft, in which a main longitudinal axis of the implantable anchoring shaft coincides with a main longitudinal axis of the angular displacement unit.

29. The assembly of claim 28, wherein the angular displacement unit comprises a pass-through bore extending between its upper surface and its convexly curved surface, and the implantable anchoring shaft comprises a respective bore extending from its concavely curved surface, said bores are being aligned in the coaxial position and configured to receive a locking member therewithin to thereby lock the angular displacement unit and the implantable anchoring shaft in the coaxial position. .

30. The assembly of any one of claims 27 to 29, wherein the angular displacement unit is configured to receive a hollow delivery unit within said axial lumen of the angular displacement unit; wherein the anchoring shaft and the angular displacement unit are configured for detachable attachment of the stimulation unit to the anchoring shaft within said axial lumen of the anchoring shaft; and wherein the delivery unit is configured to allow insertion of additional elements / utilities into the middle ear cavity.

31. The assembly of any one of claims 1 to 30, wherein the implantable anchoring shaft is made of one or more biocompatible material compositions.

32. The assembly of claim 31, wherein the implantable anchoring shaft is made of one or more MRI compatible material compositions.

33. The assembly of any one of claims 2 to 32, wherein the at least one actuator comprises a piezoelectric actuator.

34. The assembly of any one of claims 2 to 32, wherein the at least one actuator comprises an electromagnetic transducer.

35. A removable stimulation unit for use in the assembly of any one of the preceding claims.

36. A removable stimulation unit for use in a bone-anchored hearing aid assembly, said removable stimulation unit being configured for detachable attachment within an axial lumen of an implantable anchoring shaft, when mounted within a burr hole drilled in the skull of a subject, wherein said removable stimulation unit has a bottom apertureat a distal end thereof and comprises at least one actuator and a reciprocating end effector passing through said bottom aperture, said end effector being configured to perform a reciprocal movement along a main longitudinal axis of said removable stimulation unit for mechanically transmitting vibrations to a subject’s cochlear wall for perception by the subject as sound, and said at least one actuator being operatively coupled to said end effector for driving it to perform the reciprocal movement.

37. A kit for use in assembling an implantable hearing aid for mechanically transmitting vibrations to a subject’s cochlear, the kit comprising: a number N (N> 1) of removable stimulation units, each configured according to claim 34 for detachable attachment to a predetermined anchoring shaft implanted in a burr hole in the skull of a subject; and one or more tools for insertion of the removable stimulation unit to a selected depth within the implantable anchoring shaft.

38. The kit of claim 37, further comprising one or more elements to be located within at least one working channel made in the removable stimulation unit.

39. The kit according to claim 37 or 38, further comprising at least one microphone to be installed, via said removable stimulation unit, in the vicinity of the cochlea.

40. A kit for use in assembling an implantable hearing aid for mechanically transmitting vibrations to a subject’s cochlear, the kit comprising: a number N (N> 1) of anchoring shafts, each configured for implantation in a burr hole in the skull of a subject, a number M (M>1) of removable stimulation units, each removable stimulation unit being configured according to claim 35 for detachable attachment to a selected anchoring shaft upon implantation of said anchoring shaft in the burr hole in the skull; one or more tools for insertion of the implantable anchoring shaft within the burr hole drilled in the skull of the subject; and one or more tools for insertion of the removable stimulation unit to a selected depth within the implantable anchoring shaft.

41. The kit of claim 40, further comprising one or more elements to be located within at least one working channel made in the removable stimulation unit.

42. The kit according to claim 40 or 41, further comprising at least one microphone to be installed, via said removable stimulation unit, in the vicinity of the cochlea.

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