Implantable assembly preform with at least one helical channel

Abstract

An apparatus includes an assembly configured to be implanted on or within a recipient. The assembly includes a first portion having a longitudinal axis and at least one helical channel having more than one 2π-radian rotation around the longitudinal axis. The assembly further includes at least one electrical conductor extending around the longitudinal axis within the at least one helical channel, and a second portion extending over the first portion and within the at least one helical channel. The second portion covers at least a portion of the at least one electrical conductor. The assembly further includes at least one electrode in electrical communication with the at least one electrical conductor and configured to be in operative communication with a portion of the recipient.

Description

IMPLANTABLE ASSEMBLY PREFORM WITH AT LEAST ONE HELICALCHANNELBACKGROUNDField

[0001] The present application relates generally to implantable medical devices comprising stimulation or measurement assemblies and systems and methods for implanting the stimulation or measurement assemblies.Description of the Related Art

[0002] Medical devices have provided a wide range of therapeutic benefits to recipients over recent decades. Medical devices can include internal or implantable components / de vices, external or wearable components / devices, or combinations thereof (e.g., a device having an external component communicating with an implantable component). Medical devices, such as traditional hearing aids, partially or fully-implantable hearing prostheses (e.g., bone conduction devices, mechanical stimulators, cochlear implants, etc.), pacemakers, defibrillators, functional electrical stimulation devices, and other medical devices, have been successful in performing lifesaving and / or lifestyle enhancement functions and / or recipient monitoring for a number of years.

[0003] The types of medical devices and the ranges of functions performed thereby have increased over the years. For example, many medical devices, sometimes referred to as “implantable medical devices,” now often include one or more instruments, apparatus, sensors, processors, controllers or other functional mechanical or electrical components that are permanently or temporarily implanted in a recipient. These functional devices are typically used to diagnose, prevent, monitor, treat, or manage a disease / injury or symptom thereof, or to investigate, replace or modify the anatomy or a physiological process. Many of these functional devices utilize power and / or data received from external devices that are part of, or operate in conjunction with, implantable components.SUMMARY

[0004] In one aspect disclosed herein, an apparatus comprises an assembly configured to be implanted on or within a recipient. The assembly comprises a first portion having a longitudinal axis. The first portion comprises at least one helical channel having morethan one 2TT- radian rotation around the longitudinal axis. The assembly further comprises at least one electrical conductor extending around the longitudinal axis within the at least one helical channel. The assembly further comprises a second portion extending over the first portion and within the at least one helical channel. The second portion covers at least a portion of the at least one electrical conductor. The assembly further comprises at least one electrode in electrical communication with the at least one electrical conductor and configured to be in operative communication with a portion of the recipient.

[0005] In another aspect disclosed herein, a method comprises accessing an elongate preform that comprises an electrically insulative and flexible first material and at least one spiral passage having a plurality of loops encircling and distributed along a longitudinal axis of the preform. The method further comprises accessing a plurality of electrical wires each having a first end portion and a second end portion. The method further comprises winding the plurality of electrical wires around the preform within the at least one spiral passage such that first end portions of the plurality of electrical wires are spaced from one another along the longitudinal axis. The method further comprises affixing a plurality of electrodes to the first end portions of the plurality of electrical wires. The method further comprises affixing the plurality of electrodes to the preform such that the plurality of electrodes are spaced from one another along the longitudinal axis. The method further comprises encasing the plurality of electrical wires within the at least one spiral passage.

[0006] In another aspect disclosed herein, an assembly comprises a preform having a longitudinal axis. The preform comprises first regions extending a first distance substantially perpendicular to the longitudinal axis and second regions extending a second distance substantially perpendicular to the longitudinal axis. The second distance is less than the first distance, and the second regions form at least one spiral passage around the longitudinal axis between the first regions. The assembly further comprises a plurality of electrical conduits, each electrical conduit comprising an electrically conductive wire wrapped around the longitudinal axis and within the at least one spiral passage and an electrode in electrical communication with the electrically conductive wire. The electrode has an outer surface facing away from the longitudinal axis. The assembly further comprises an electrically insulating overlayer extending over the first and second regions, covering at least a portion of eachelectrical conduit while not covering at least a portion of the outer surface of the electrode of the electrical conduit.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Implementations are described herein in conjunction with the accompanying drawings, in which:

[0008] FIG. 1 is a perspective view of an example auditory prosthesis implanted in a recipient with a stimulation assembly inserted into the cochlea in accordance with certain implementations described herein;

[0009] FIG. 2 schematically illustrates a simplified side view of an example internal component of an auditory prosthesis in accordance with certain implementations described herein;

[0010] FIG. 3 is cross-sectional view of the cochlea illustrating a stimulating assembly partially implanted therein in accordance with certain implementations described herein;

[0011] FIGs. 4A-4F schematically illustrate various configurations during an example implantation of a perimodiolar stimulation assembly into the cochlea of the recipient in accordance with certain implementations described herein;

[0012] FIGs. 5A-5C schematically illustrate side views of portions of various example apparatus comprising an assembly in accordance with certain implementations described herein;

[0013] FIGs. 6 A and 6B schematically illustrate perspective and side views, respectively, of an example first portion comprising a single helical protrusion and a single helical channel in accordance with certain implementations described herein;

[0014] FIGs. 7 A and 7B schematically illustrate perspective and side views, respectively, of an example first portion comprising a plurality of protrusion distributed along the longitudinal axis and having side surface portions that at least partially bound a single helical channel in accordance with certain implementations described herein;

[0015] FIGs. 8 A and 8B schematically illustrate perspective and side views, respectively, of an example first portion comprising a plurality of protrusion distributed along the longitudinal axis and having side surface portions that at least partially bound two helical channels in accordance with certain implementations described herein;

[0016] FIG. 9 is a flow diagram of an example method in accordance with certain implementations described herein; and

[0017] FIGs. 10A-10C schematically illustrate an example assembly at various stages of fabrication in accordance with certain implementations described herein.DETAILED DESCRIPTION

[0018] Certain implementations described herein provide an electrode lead assembly comprising a preform having one or more protrusions (e.g., lateral or sideways projections) that at least partially bound at least one helical channel configured to facilitate spirally winding electrical conductors (e.g., wires) around the preform. The one or more protrusions can also facilitate centering the preform with the electrical conductors during a subsequent over-molding procedure that forms a protective layer extending into the at least one helical channel and covering the electrical conductors therein.

[0019] The teachings detailed herein are applicable, in at least some implementations, to any type of implantable stimulation or measurement system (e.g., implantable auditory prosthesis device or system; neurostimulation system; machine-brain interface system; muscle stimulation system). The system can comprise a first portion implanted on or within the recipient’s body and a second portion (e.g., implanted on or within the recipient or external to the recipient’s body). For example, the first portion can be configured to provide stimulation signals to a portion of the recipient’s body in response to received information and / or control signals from the second portion of the system. For another example, the first portion can be configured to generate sensor signals indicative of an attribute of the portion of the recipient’s body and to provide the sensor signals to the second portion. Implementations can include any type of medical device that can utilize the teachings detailed herein and / or variations thereof. Furthermore, while certain implementations are described herein in the context of auditory prosthesis devices, certain other implementations are compatible in the context of other types of devices or systems that provide a wide range of therapeutic benefits to recipients, patients, or other users.

[0020] Merely for ease of description, apparatus and methods disclosed herein are primarily described with reference to an illustrative medical device, namely an implantable transducer assembly including but not limited to: electro-acoustic electrical / acoustic systems, cochlear implant devices, implantable hearing aid devices, middle ear implant devices, boneconduction devices (e.g., active bone conduction devices; passive bone conduction devices, percutaneous bone conduction devices; transcutaneous bone conduction devices), Direct Acoustic Cochlear Implant (DACI), middle ear transducer (MET), electro-acoustic implant devices, other types of auditory prosthesis devices, and / or combinations or variations thereof, or any other suitable hearing prosthesis system with or without one or more external components. Certain such implementations can be referred to as “partially implantable,” “semi-implantable,” “mostly implantable,” “fully implantable,” or “totally implantable” auditory prostheses. In some implementations, the teachings detailed herein and / or variations thereof can be utilized in other types of prostheses beyond auditory prostheses.

[0021] In some implementations, the teachings detailed herein and / or variations thereof can be utilized in other types of implantable medical devices beyond auditory prostheses. For example, apparatus and methods disclosed herein and / or variations thereof can also be used with other types of sensory prosthesis systems or devices (e.g., configured to evoke other types of neural or sensory percepts such as sight, tactile, smell, taste) or with other types of medical devices that can utilize the teachings detailed herein and / or variations thereof to provide a wide range of therapeutic benefits to recipients, patients, or other users, such as one or more of the following: vestibular devices (e.g., vestibular implants); tinnitus treatment devices; visual devices (e.g., bionic eyes); visual prostheses (e.g., retinal implants); cardiac pacemakers; drug delivery systems; defibrillators; functional electrical stimulation devices; catheters; neurostimulators; brain implants; somatosensory implants; chemosensory implants; seizure devices (e.g., devices for monitoring and / or treating epileptic events); sleep apnea devices; electroporation devices; pain relief devices; bladder control devices; swallowing treatment devices (e.g., devices for treating difficulties with the hyoglossus and / or thyrohyoid muscles); dysphagia treatment devices; devices for treating dry mouth (e.g., xerostomia or hyposalivation), devices for treating excessive or absence of muscle movement due to stroke, Parkinson’s disease, or other brain disorders, devices for treating hypertension (e.g., by stimulating the carotid sinus barosensory system); etc. Other example apparatus and methods disclosed herein and / or variations thereof can be used to perform monitoring or measuring functionalities (e.g., sensors; electroencephalogram monitoring of brain function; electrocardiogram monitoring of heart function).

[0022] FIG. 1 is a perspective view of an example auditory prosthesis 100 (e.g., cochlear implant), implanted in a recipient with a stimulation assembly 118 inserted into the cochlea 140 in accordance with certain implementations described herein. As shown in FIG. 1, the recipient has an outer ear 101, a middle ear 105, and an inner ear 107. In a fully functional ear, the outer ear 101 comprises an auricle 110 and an ear canal 102. An acoustic pressure or sound wave 103 is collected by the auricle 110 and is channeled into and through the ear canal 102. Disposed across the distal end of the ear canal 102 is a tympanic membrane 104 which vibrates in response to the sound wave 103. This vibration is coupled to oval window or fenestra ovalis 112 through three bones of middle ear 105, collectively referred to as the ossicles 106 and comprising the malleus 108, the incus 109, and the stapes 111. The bones 108, 109, and 111 of the middle ear 105 serve to filter and amplify the sound wave 103, causing the oval window 112 to articulate, or vibrate in response to vibration of the tympanic membrane 104. This vibration sets up waves of fluid motion of the perilymph within the cochlea 140. Such fluid motion, in turn, activates tiny hair cells (not shown) inside the cochlea 140. Activation of the hair cells causes appropriate nerve impulses to be generated and transferred through the spiral ganglion cells (not shown) and auditory nerve 114 to the brain (also not shown) where they are perceived as sound.

[0023] As shown in FIG. 1, the example auditory prosthesis 100 comprises one or more components which are temporarily or permanently implanted in the recipient. The example auditory prosthesis 100 is shown in FIG. 1 with an external component 142 which is directly or indirectly attached to the recipient’s body, and an internal component 144 which is temporarily or permanently implanted in the recipient (e.g., positioned in a recess of the temporal bone adjacent to the auricle 110 of the recipient). The external component 142 typically comprises one or more sound input elements (e.g., an external microphone 124) for detecting sound, a sound processing unit 126 (e.g., disposed in a Behind-The-Ear unit), a power source (not shown), and an external transmitter unit 128. In the illustrative implementation of FIG. 1, the external transmitter unit 128 comprises an external coil 130 (e.g., a wire antenna coil comprising multiple turns of electrically insulated single-strand or multi-strand platinum or gold wire) and, preferably, a magnet (not shown) secured directly or indirectly to the external coil 130. The external coil 130 of the external transmitter unit 128 is part of an inductive radio frequency (RF) communication link with the internal component 144. Thesound processing unit 126 processes the output of the microphone 124 that is positioned externally to the recipient’s body, in the depicted implementation, by the recipient’s auricle 110. The sound processing unit 126 generates encoded signals, sometimes referred to herein as encoded data signals, which are provided to the external transmitter unit 128 (e.g., via a cable).

[0024] The power source of the external component 142 is configured to provide power to the auditory prosthesis 100, where the auditory prosthesis 100 includes a battery (e.g., located in the internal component 144, or disposed in a separate implanted location) that is recharged by the power provided from the external component 142 (e.g., via a transcutaneous energy transfer link). The transcutaneous energy transfer link is used to transfer power and / or data to the internal component 144 of the auditory prosthesis 100. Various types of energy transfer, such as infrared (IR), electromagnetic, capacitive, and inductive transfer, may be used to transfer the power and / or data from the external component 142 to the internal component 144. During operation of the auditory prosthesis 100, the power stored by the rechargeable battery is distributed to the various other implanted components as needed.

[0025] The internal component 144 comprises an internal receiver unit 132, a stimulator unit 120, and an elongate stimulation assembly 118. In some implementations, the internal receiver unit 132 and the stimulator unit 120 are hermetically sealed within a biocompatible housing, sometimes collectively referred to as a stimulator / receiver unit. The internal receiver unit 132 comprises an internal coil 136 (e.g., a wire antenna coil comprising multiple turns of electrically insulated single-strand or multi-strand platinum or gold wire), and preferably, a magnet (also not shown) fixed relative to the internal coil 136. The internal coil 136 receives power and / or data signals from the external coil 130 via a transcutaneous energy transfer link (e.g., an inductive RF link). The stimulator unit 120 generates electrical stimulation signals based on the data signals, and the stimulation signals are delivered to the recipient via the elongate stimulation assembly 118.

[0026] The elongate stimulation assembly 118 has a proximal end connected to the stimulator unit 120, and a distal end implanted in the cochlea 140. The stimulation assembly 118 extends from the stimulator unit 120 to the cochlea 140 through the mastoid bone 119. In some implementations, the stimulation assembly 118 may be implanted at least in the basal region 116, and sometimes further. For example, the stimulation assembly 118 may extendtowards the apical end of the cochlea 140, referred to as the cochlea apex 134. In certain circumstances, the stimulation assembly 118 may be inserted into the cochlea 140 via a cochleostomy 122. In other circumstances, a cochleostomy 122 may be formed through the round window 121, the oval window 112, the promontory 123, or through an apical turn 147 of the cochlea 140.

[0027] The elongate stimulation assembly 118 comprises a longitudinally aligned and distally extending array 146 (e.g., electrode array; contact array) of stimulation elements 148 (e.g., electrical electrodes; electrical contacts; optical emitters; optical contacts). For example, the stimulation elements 148 can comprise intra-cochlear electrodes (ICEs) and / or extra-cochlear electrodes (ECEs). The stimulation elements 148 are longitudinally spaced from one another along a length of the elongate body of the stimulation assembly 118. For example, the stimulating assembly 118 can comprise an array 146 comprising twenty-two (22) stimulation elements 148 that are configured to deliver stimulation to the cochlea 140. Although the array 146 of stimulation elements 148 can be disposed on the stimulation assembly 118, in most practical applications, the array 146 is integrated into the stimulation assembly 118 (e.g., the stimulation elements 148 of the array 146 are disposed in the stimulation assembly 118). As noted, the stimulator unit 120 generates stimulation signals (e.g., electrical signals; optical signals) which are applied by the stimulation elements 148 to the cochlea 140, thereby stimulating the auditory nerve 114.

[0028] While FIG. 1 schematically illustrates an auditory prosthesis 100 utilizing an external component 142 comprising an external microphone 124, an external sound processing unit 126, and an external power source, in certain other implementations, one or more of the microphone 124, sound processing unit 126, and power source are implantable on or within the recipient (e.g., within the internal component 144). For example, the auditory prosthesis 100 can have each of the microphone 124, sound processing unit 126, and power source implantable on or within the recipient (e.g., encapsulated within a biocompatible assembly located subcutaneously), and can be referred to as a totally implantable cochlear implant (“TICI”). For another example, the auditory prosthesis 100 can have most components of the cochlear implant (e.g., excluding the microphone, which can be an in-the-ear-canal microphone) implantable on or within the recipient, and can be referred to as a mostly implantable cochlear implant (“MICI”).

[0029] A variety of types of intra-cochlear stimulation assemblies 118 are compatible with certain implementations described herein, including but not limited to: short, straight, and perimodiolar. A perimodiolar stimulation assembly 118 is configured to adopt a curved configuration during and / or after implantation into the cochlea 140. To achieve this, in certain implementations, the perimodiolar stimulation assembly 118 is pre-curved to the same general curvature of the cochlea 140. Such examples of the stimulation assembly 118 can be held straight by, for example, a stiffening stylet (not shown in FIG. 1) or sheath 260 which is removed during implantation, or alternatively varying material combinations or the use of shape memory materials, so that the stimulation assembly 118 may adopt its curved configuration when in the cochlea 140. Other methods of implantation, as well as other stimulation assemblies 118 which adopt a curved configuration, may be used. The stimulation assembly 118 of certain other implementations comprises a non-perimodiolar stimulation assembly 118. For example, the stimulation assembly 118 can comprise a straight stimulation assembly 118 or a mid-scala assembly which assumes a mid-scala position during or following implantation. Alternatively, the stimulation assembly 118 can comprise a short electrode implanted into at least the basal region of the cochlea 140. The stimulation assembly 118 can extend towards the apical end of the cochlea 140, referred to as the cochlea apex. In certain implementations, the stimulation assembly 118 is configured to be inserted into the cochlea 140 via a cochleostomy (e.g., formed through the oval window 112, the round window 121, the promontory 123, or through an apical turn of the cochlea 140).

[0030] FIG. 2 schematically illustrates a simplified side view of an example internal component 144 comprising an internal receiver unit 132 which receives encoded signals from an external component 142 of the auditory prosthesis 100 (e.g., cochlear implant system). The internal component 144 terminates in the stimulation assembly 118 that comprises an extra-cochlear region 210 and an intra-cochlear region 212. The intra-cochlear region 212 is configured to be implanted in the recipient’s cochlea 140 and has disposed thereon the longitudinally aligned and distally extending array 146 (e.g., electrode array; contact array) comprising a plurality of stimulation elements 148. In the example schematically illustrated in FIG. 2, the plurality of stimulation elements 148 comprises electrical contacts (e.g., electrodes) configured to apply electrical stimulation and / or opticalcontacts (e.g., emitters) configured to apply optical stimulation, either alone or in conjunction with electrical or other stimulation mechanisms.

[0031] In certain implementations, the stimulation assembly 118 comprises a lead region 220 coupling the internal receiver unit 132 to the array 146. In certain implementations, optical and / or electrical stimulation signals generated by the internal receiver unit 132 are delivered to the array 146 via the lead region 220. The lead region 220 comprises a first portion 222 configured to accommodate movement (e.g., is flexible) and a second portion 224 configured to connect the first portion 222 to the array 146. The first portion 222 of certain implementations is configured to prevent the stimulation assembly 118, the lead region 220 and its connection to the internal receiver unit 132, and the array 146 from being damaged due to movement of the internal component 144 (or part of the internal component 144) which may occur, for example, during mastication. In certain implementations, the second portion 224 comprises a distinct connection to the first portion 222 and / or the array 146, while in certain other implementations, the second portion 224 is blended into the first portion 222 and / or the array 146. The relative lengths of the stimulation assembly 118, the lead region 220, the first portion 222, the second portion 224, the extra-cochlear region 210, the intra-cochlear region 212, and the array 146 are not shown to scale in FIG. 2.

[0032] In certain implementations, the lead region 220 comprises a body 226 and a plurality of signal conduits (e.g., electrical wire leads; optical waveguides)(not shown) within the body 226. For example, the body 226 can comprise silicone or other biocompatible material in which the signal conduits are embedded (e.g., the body 226 is molded around the signal conduits) or the body 226 can comprise a tube in which the signal conduits are contained (e.g., the tube backfilled with silicone). The signal conduits of certain implementations comprise wires (e.g., platinum; platinum-iridium alloys) and / or one or more optical fibers or waveguides (e.g., silica-based glass or plastic) having outer diameters that are wavy or helixed around an axis substantially parallel to the longitudinal direction of the lead region 220 (e.g., within the first portion 222) and / or are substantially straight and substantially parallel to the longitudinal direction (e.g., within the second portion 224). In certain implementations, each of the signal conduits is operatively connected to a corresponding one of the plurality of stimulation elements 148 of the array 146.

[0033] In certain implementations, the extra-cochlear region 210 is located in the middle ear cavity of the recipient after implantation of the intra-cochlear region 212 into the cochlea 140. Thus, the extra-cochlear region 210 corresponds to a middle ear cavity subsection of the array 146. In certain implementations, an outer surface of the extra-cochlear region 210 comprises nubs 214 configured to aid in the manipulation of the stimulation assembly 118 during insertion of the intra-cochlear region 212 into the cochlea 140.

[0034] FIG. 3 is cross-sectional view of the cochlea 140 illustrating the stimulating assembly 118 partially implanted therein in accordance with certain implementations described herein. Only a subset of the stimulation elements 148 of the stimulation assembly 118 is shown in FIG. 3. The cochlea 140 is a conical spiral structure that comprises three parallel fluid- filled canals or ducts, collectively and generally referred to herein as canals 236. Canals 236 comprise the tympanic canal 237, also referred to as the scala tympani 237, the vestibular canal 238, also referred to as the scala vestibuli 238, and the median canal 239, also referred to as the scala media 239. The cochlea 140 includes the modiolus 240 which is a conical shaped central region around which the cochlea canals 236 spiral. The modiolus 240 consists of spongy bone in which the cochlea nerve cells, sometimes referred to herein as the spiral ganglion cells, are situated. The cochlea canals 236 generally turn 2.5 times around the modiolus 240.

[0035] In normal hearing, sound entering the auricle 110 (see, e.g., FIG. 1) causes pressure changes in the cochlea 140 that travel through the fluid-filled tympanic and vestibular canals 237, 238. The organ of Corti 242, which is situated on the basilar membrane 244 in scala media 239, contains rows of hair cells (not shown) which protrude from its surface. Located above the hair cells is the tectoral membrane 245 which moves in response to pressure variations in the fluid-filled tympanic and vestibular canals 237, 238. Small relative movements of the layers of the tectoral membrane 245 are sufficient to cause the hair cells to move, thereby causing the creation of a voltage pulse or action potential which travels along the associated nerve fibers that connect the hair cells with the auditory nerve 114. The auditory nerve 114 relays the impulses to the auditory areas of the brain (not shown) for processing.

[0036] Typically, in cochlear implant recipients, some portion of the cochlea 140 (e.g., the hair cells) is damaged such that the cochlea 140 cannot transduce pressure changes into nerve impulses for relay to the brain. As such, the stimulating elements 148 of thestimulating assembly 118 are used to directly stimulate the cells to create nerve impulses resulting in perception of a received sound (e.g., to evoke a hearing percept).

[0037] FIGs. 4A-4F schematically illustrate various configurations during an example implantation of a perimodiolar stimulation assembly 118 into the cochlea 140 of the recipient in accordance with certain implementations described herein. The perimodiolar stimulation assembly 118 is substantially enclosed in a sheath 260 (e.g., cannula; insertion tube) of an insertion tool configured to protect the stimulation assembly 118 during the implantation process. The sheath 260 is further configured to provide sufficient rigidity to maintain the pre-curved perimodiolar stimulation assembly 118 in a substantially straight configuration during at least a portion of the implantation process. While FIGs. 4A-4F schematically illustrate an example implantation of a perimodiolar stimulation assembly 118 into a cochlea 140 using a sheath 260, in certain other implementations, other types of assemblies (e.g., straight) can be inserted into other regions of the recipient’s body by other means (e.g., no sheath; using a stylet).

[0038] In certain implementations, the implantation process includes creating an opening (e.g., facial recess) through the recipient's mastoid bone 119 (see, e.g., FIG. 1) to access the recipient's middle ear cavity (see, e.g., FIG. 1). A cochleostomy 122 is created from the middle ear cavity into the cochlea 140 (e.g., through the round window 121, oval window 112, the promontory 123, etc. of the cochlea 140). The stimulation assembly 118 and the surrounding sheath 260 are advanced (e.g., pushed) through the opening through the mastoid bone 119 and are positioned to be inserted into the cochleostomy 122, as schematically illustrated in FIG. 4A.

[0039] As schematically illustrated in FIG. 4B, the stimulation assembly 118 and the sheath 260 are advanced (e.g., pushed) together through the cochleostomy 122 to insert a distal end portion 262 of the sheath 260 within the cochlea 140 while the stimulation assembly 118 remains in the sheath 260. The advancement of the stimulation assembly 118 and the surrounding sheath 260 is stopped once a proximal end portion 264 of the sheath 260 is in a predetermined position (e.g., in contact with the cochlea 140 at the cochleostomy 122). As schematically illustrated by FIG. 4C, the stimulation assembly 118 is then gently advanced (e.g., pushed) forward into the cochlea 140 through the sheath 260 such that an apical (e.g., distal end / tip) portion 228 of the array 146 exits the sheath 260 through an opening in the distalend portion 262 of the sheath 260. The portion of the stimulation assembly 118 that extends out of the sheath 260 is no longer constrained to be straight by the stimulation assembly 118 and therefore returns to its pre-curved configuration to follow the curvature of the canals 236 within the cochlea 140. As schematically illustrated by FIG. 4D, the advancement of the stimulation assembly 118 continues until the stimulation assembly 118 achieves the implanted position. For example, the implanted position can be the position at which the apical portion 228 of the array 146 is placed at a selected angular position (e.g., the apical portion 228 of the array 146 is at the cochlea apex 134). Once the stimulation assembly 118 achieves the implanted position, the sheath 260 can be withdrawn from the cochlea 140 (e.g., pulled out) through the cochleostomy 122, as schematically illustrated by FIGs. 4E-4F.

[0040] The effectiveness of the stimulation by the stimulation assembly 118 depends, at least in part, on the place along the basilar membrane 244 where the stimulation is delivered. That is, the cochlea 140 has characteristically been referred to as being "tonotopically mapped," in that regions of the cochlea 140 toward the basal end are more responsive to high frequency signals, while regions of cochlea 140 toward the cochlea apex 134 are more responsive to low frequency signals. These tonotopical properties of the cochlea 140 are exploited in a cochlear implant by delivering stimulation within a predetermined frequency range to a region of the cochlea 140 that is most sensitive to that particular frequency range. However, this stimulation relies on the particular stimulation elements 148 having a final implanted positioned adjacent to a corresponding tonotopic region of the cochlea 140 (e.g., a region of the cochlea 140 that is sensitive to the frequency of sound represented by the stimulation element 148).

[0041] To achieve a selected final implanted position, the apical portion 228 of the array 146 is placed at a selected angular position (e.g., angular insertion depth; angular rotation of the apical portion 228 of the array 146 from the cochleostomy 122 through which the stimulation assembly 118 enters the cochlea 140). In certain implementations, while the stimulation assembly 118 is being implanted (e.g., during a surgical procedure conducted by an operator, such as a medical professional, surgeon, and / or an automated or robotic surgical system), a location and / or an orientation of the array 146 relative to the cochlea 140 (e.g., collectively referred to as the pose of the array 146) is adjusted as the array 146 is advanced and placed into position within the cochlea 140. The goal of the implantation is that the fully-implanted array 146 has an optimal pose in which the array 146 is positioned such that the stimulation elements 148 are adjacent to the corresponding tonotopic regions of the cochlea 140. To achieve the optimal pose, the array 146 is expected to follow a trajectory in the cochlea 140 whereby (i) the stimulation elements 148 are distributed linearly along an axis of the scala media 239, (ii) the array 146 does not make contact with the basilar membrane 244, and (iii) the stimulation elements 148 are in close proximity to the modiolar wall (e.g., if the array 146 is pre-curved) or the stimulation elements 148 are distant from the modiolar wall (e.g., if the array 146 is not pre-curved).

[0042] However, the stimulation assembly 118, including the array 146, can experience various damaging forces under certain circumstances. For example, during insertion and / or extraction of the array 146, tensile forces can cause damage (e.g., breakage) of the signal conduits (e.g., electrical wire leads; optical waveguides) of the stimulation assembly 118 that extend from the stimulator unit 120, through the lead region 220 to the stimulation elements 148 or can cause detachment of the signal conduits from the stimulation elements 148. In addition, the stimulation assembly 118 can experience twisting (e.g., rotation about the longitudinal axis 322) due to torsional forces (e.g., during insertion) which can move the stimulation elements 148 from predetermined implantation positions.

[0043] FIGs. 5A-5C schematically illustrate side views of portions of various example apparatus 300 comprising an assembly 310 (e.g., stimulation assembly 118; internal component 144) in accordance with certain implementations described herein. The assembly 310 is configured to be implanted on or within a recipient and comprises a first portion 320, at least one electrical conductor 330, a second portion 340, and at least one electrode 350. The first portion 320 has a longitudinal axis 322 and comprises at least one helical channel 324 (e.g., slot; passage) having more than one 2TT- radian rotation around the longitudinal axis 322. The at least one electrical conductor 330 extends around the longitudinal axis 322 within the at least one helical channel 324. The second portion 340 extends over the first portion 320 and within the at least one helical channel 324, the second portion 340 covering at least a portion of the at least one electrical conductor 330. The at least one electrode 350 is in electrical communication with the at least one electrical conductor 330 and is configured to be in operative communication with a portion (e.g., tissue; bodily fluid) of the recipient.

[0044] In certain implementations, the apparatus 300 further comprises an insertion element (e.g., tube; sheath 260; stylet) in mechanical communication with the assembly 310. The assembly 310 can be configured to be implanted within a region of the recipient’s body by inserting at least a portion of the insertion element into the region and sliding the assembly 310 along the insertion element such that the assembly 310 extends at least partially into the region. For example, the apparatus 300 comprising the insertion element and the assembly 310 can be shipped and / or stored in a hermetically sealed container. After opening the container and removing the apparatus 300 from the container, the assembly 310 can be implanted using the insertion element (see, e.g., FIGs. 4A-4F). After implanting the assembly 310, the insertion element can be removed from the recipient’s body and discarded.

[0045] In certain implementations, the assembly 310 is flexible and is configured to be controllably bent while being implanted on or within the recipient to extend along a predetermined pathway upon being implanted. For example, the assembly 310 can be sufficiently flexible to be at least partially inserted into a cochlea 140 of the recipient or to be bent to curve along a portion of the recipient’s skull (e.g., along a distance in a range of 5 centimeters to 40 centimeters; 30 centimeters). For another example, the assembly 310 can comprise a perimodiolar stimulation assembly 118 configured to adopt a curved configuration during and / or after implantation (e.g., into the cochlea 140; see, e.g., FIGs. 4A-4F). The assembly 310 can be sufficiently flexible such that at least a first portion of the assembly 310 in mechanical communication with the insertion element has a first, substantially straight shape and during insertion, at least a second portion of the assembly 310 extending away from the insertion element has a second, substantially curved (e.g., spiral) shape (e.g., with a radius of curvature in a range of 2 millimeters to 5 millimeters; configured to conform to the curvature of the canals 236 of the human cochlea 140).

[0046] In certain implementations, the assembly 310 further comprises at least one reinforcement element within (e.g., encased by; surrounded by) the first portion 320 and extending along and substantially parallel to the longitudinal axis 322. For example, the at least one reinforcement element (e.g., ribbon; strip; band; film; suture; wire) can be straight or helical (e.g., around the longitudinal axis 322; providing axial flexibility) and can be configured to provide structural reinforcement (e.g., stiffness) to the assembly 310 to inhibit (e.g., resist, prevent, limit, reduce, or minimize) breakage of the at least one electricalconductor 330 due to tensile forces applied to the assembly 310. The at least one reinforcement element can comprise at least one biocompatible material, examples of which include but are not limited to: polymer; polyamide; mesh; fibers, cords, or strands; carbon fibers; silk; metal; platinum; metal alloy; nickel-titanium alloy (e.g., nitinol); shape-memory alloy. The at least one reinforcement element can comprise a single contiguous reinforcement element or multiple reinforcement elements that at least partially overlap one another.

[0047] In certain implementations, the first portion 320 comprises an electrically insulative and flexible first material and / or the second portion 340 (e.g., overlayer) comprises an electrically insulative and flexible second material. For example, the first material and / or the second material can comprise at least one elastomeric material. Examples of elastomeric materials compatible with certain implementations described herein include but are not limited to: silicone; silicone rubber; other biocompatible polymers. In certain implementations, the first material of the first portion 320 is the same as the second material of the second portion 340 (e.g., both the first and second materials comprise silicone), while in certain other implementations, the first material is different from the second material. In certain implementations, the first portion 320 and / or the second portion 340 has a substantially circular cross-sectional shape in a plane substantially perpendicular to the longitudinal axis 322. The first portion 320 and / or the second portion can have a first width in a first direction substantially perpendicular to the longitudinal axis 322 and a second width in a second direction substantially perpendicular to the longitudinal axis 322 and the first direction. The first width can be substantially equal to the second width or the first width can be greater than the second width. The first width and / or the second width can be in a range of 0.1 millimeter to 0.6 millimeter (e.g., in a range of 0.2 millimeter to 0.4 millimeter; in a range of 0.3 millimeter to 0.5 millimeter). Other cross-sectional shapes (e.g., substantially oval; substantially rectangular; substantially square; polygonal; symmetric; asymmetric) and dimensions are also compatible with certain implementations described herein.

[0048] In certain implementations, the first portion 320 comprises at least one helical protrusion 326 (e.g., spindel; bump) having side surface portions 327 that at least partially bound the at least one helical channel 324. The at least one helical channel 324 can have more than two (e.g., more than 4; in a range of 2 to 5; in a range of 5 to 10; in a range of 10 to 20; in a range of 20 to 50; in a range of 50 to 100; in a range of 100 to 200; more than200) 2TT- radian rotations around the longitudinal axis 322 (e.g., loops or turns encircling the longitudinal axis 322).

[0049] In certain implementations, as schematically illustrated by FIGs. 5A-5C, the at least one helical protrusion 326 can comprise a single protrusion 326 having a spiral shape that extends around the longitudinal axis 322 and having a pair of side surface portions 327 that at least partially bound a single helical channel 324. In certain other implementations, the at least one helical protrusion 326 can comprise multiple helical protrusions 326 distributed and extending along the longitudinal axis 322. Each of the multiple protrusions 326 can have a spiral shape that extends around the longitudinal axis 322 and can have a pair of side surface portions 327 that at least partially bound a corresponding helical channel 324 (e.g., the same helical channel 324 as one another; separate helical channels 324). The at least one helical protrusion (e.g., single protrusion 326; multiple protrusions 326) can have more than two (e.g., more than 4; in a range of 2 to 5; in a range of 5 to 10; in a range of 10 to 20; in a range of 20 to 50; in a range of 50 to 100; in a range of 100 to 200; more than 200) lit- radian rotations around the longitudinal axis 322 (e.g., loops or turns encircling the longitudinal axis 322).

[0050] FIGs. 6 A and 6B schematically illustrate perspective and side views, respectively, of an example first portion 320 comprising a single helical (e.g., spiral) protrusion 326 and a single helical (e.g., spiral) channel 324 in accordance with certain implementations described herein. FIGs. 7 A and 7B schematically illustrate perspective and side views, respectively, of an example first portion 320 comprising a plurality of protrusion 326 distributed along the longitudinal axis 322 and having side surface portions 327 that at least partially bound a single helical (e.g., spiral) channel 324 in accordance with certain implementations described herein. FIGs. 8A and 8B schematically illustrate perspective and side views, respectively, of an example first portion 320 comprising a plurality of protrusion 326 distributed along the longitudinal axis 322 and having side surface portions 327 that at least partially bound two helical (e.g., spiral) channels 324 in accordance with certain implementations described herein.

[0051] As shown in FIGs. 6A-6B, 7A-7B, and 8A-8B, the first portion 320 can have a substantially circular cross-section in a plane substantially perpendicular to the longitudinal axis 322. The first portion 320 at the at least one protrusion 326 can have a first radius Ri substantially perpendicular to the longitudinal axis 322, and the first portion 320 atthe at least one helical channel 324 can have a second radius R2 substantially perpendicular to the longitudinal axis 322. Both the first radius Ri and the second radius R2 can be in a range of 0.3 millimeter to 2 millimeters and the difference between the first radius Ri and the second radius R2 can be in a range of 0.2 millimeter to 1 millimeter (e.g., the first radius Ri can be 0.8 millimeter and the second radius R2 can be 0.5 millimeter). In certain implementations, the first radius Ri and / or the second radius R2 is substantially constant along the longitudinal axis 322, while in certain other implementations, the first radius Ri and / or the second radius R2 varies along the longitudinal axis 322 (e.g., first radius Ri and / or the second radius R2 smaller at a distal (e.g., apical) region of the first portion 320 than at a proximal region of the first portion 320; varying in a step-wise manner; varying continuously or monotonically).

[0052] The at least one protrusion 326 can have a first protrusion width Wpiin a direction substantially parallel to the longitudinal axis 322 (e.g., in a range of 0.1 millimeter to 2 millimeters; 0.2 millimeter) and the at least one helical channel 324 can have a channel width Wcin the direction substantially parallel to the longitudinal axis 322 (e.g., in a range of 0.1 millimeter to 2 millimeters; 0.2 millimeter). The at least one helical channel 324 can be sufficiently large such that the material of the second portion 340 can flow into the at least one helical channel 324 (e.g., during injection molding of the second portion 340 in a fabrication process of the assembly 310) and around portions of the at least one electrical conductor 330 within the at least one helical channel 324 such that the first and second portions 320,340 encase the portions of the at least one electrical conductor 330. In certain implementations in which the at least one protrusion 326 comprises a plurality of protrusions 326, the protrusions 326 have a second protrusion width WP2 in a direction substantially perpendicular to the first protrusion width Wpiand to the longitudinal axis 322 (e.g., in a range of 0.1 millimeter to 2 millimeters; 0.2 millimeter). In certain implementations, the first protrusion width Wpiis greater than or equal to the second protrusion width WP2, while in certain implementations, the first protrusion width Wp1 is less than or equal to the second protrusion width WP2. In certain implementations, the second protrusion width WP2 is substantially constant along the longitudinal axis 322, while in certain other implementations, the second protrusion width WP2 varies along the longitudinal axis 322 (e.g., second protrusion width WP2 smaller at a distal (e.g., apical) region of the first portion 320 than at a proximal region of the first portion 320; varying in a step-wise manner; varying continuously or monotonically).

[0053] In certain implementations, the first protrusion width Wpiis greater than or equal to the channel width Wc, while in certain implementations, the first protrusion width Wpiis less than or equal to the channel width Wc. In certain implementations, the first protrusion width Wpiand / or the channel width Wcis substantially constant along the longitudinal axis 322, while in certain other implementations, the first protrusion width Wpiand / or the channel width Wc varies along the longitudinal axis 322 (e.g., first protrusion width Wpiand / or the channel width Wcsmaller at a distal (e.g., apical) region of the first portion 320 than at a proximal region of the first portion 320; varying in a step-wise manner; varying continuously or monotonically). In certain implementations, the at least one helical channel 324 and / or the at least one protrusion 326 has a pitch P (e.g., equal to the sum of first protrusion width Wpiand the channel width Wc) along a direction substantially parallel to the longitudinal axis 322, the pitch P in a range of 0.1 millimeter to 4 millimeters (e.g., 0.2 millimeter to 2 millimeters; 0.4 millimeter). In certain implementations, the pitch P of at least a portion of the at least one helical channel 324 is substantially constant along the longitudinal axis 322, while in certain other implementations, the pitch P of at least a portion of the at least one helical channel 324 varies along the longitudinal axis 322 (e.g., pitch P smaller at a distal (e.g., apical) region of the first portion 320 than at a proximal region of the first portion 320; varying in a step-wise manner; varying continuously or monotonically).

[0054] FIGs. 6A-6B show an example in which each of the single helical channel 324 and the single helical protrusion 326 have a first chirality (e.g., direction of rotations relative to a direction along the longitudinal axis 322, such as from a proximal region to a distal region of the first portion 320). In other examples, the single helical channel 324 and the single helical protrusion 326 can have a second chirality opposite to the first chirality (e.g., opposite direction of rotations relative to the direction along the longitudinal axis 322, such as from the proximal region to the distal region of the first portion 320; the single helical channel 324 and the single helical protrusion 326 are enantiomers of those shown in FIGs. 6A-6B). In certain implementations, as schematically illustrated by FIGs. 6A-6B, the first portion 320 does not include any channels that are substantially parallel to the longitudinal axis 322, while in certain other implementations, the first portion 320 includes at least one channel that is substantially parallel to the longitudinal axis 322 (e.g., holes extending through the helical protrusion 326).

[0055] FIGs. 7A-7B show an example in which the at least one helical channel 324 and the plurality of protrusions 326 each have a first chirality, while in other examples, the at least one helical channel 324 and the plurality of protrusions 326 each have a second chirality opposite to the first chirality (e.g., are enantiomers of those shown in FIGs. 7A-7B). In certain implementations, as schematically illustrated by FIGs. 7A-7B, the first portion 320 includes at least one channel that is substantially parallel to the longitudinal axis 322 (e.g., extending between the protrusions 326), while in certain other implementations, the first portion 320 does not include any channels that are substantially parallel to the longitudinal axis 322.

[0056] FIGs. 8A-8B show an example in which the two helical channels 324 have opposite chirality to one another and the plurality of protrusions 326 is achiral. The protrusions 326 of FIGs. 8A-8B each have a first width Wpithat is substantially equal to the second width WP2. In certain implementations, as schematically illustrated by FIGs. 8A-8B, the first portion 320 includes at least one channel that is substantially parallel to the longitudinal axis 322 (e.g., extending between the protrusions 326), while in certain other implementations, the first portion 320 does not include any channels that are substantially parallel to the longitudinal axis 322.

[0057] In certain implementations, the second portion 340 comprises a material containing at least one substance (e.g., medicament; drug; antimicrobial agent; antiinflammatory agent; oto-protective agent; neuroregenerative agent; neurotropic agent; gene therapy agent) and is configured to controllably introduce (e.g., release; elute) the at least one substance into the recipient’s body (e.g., tissue; bodily fluid). For example, the second portion 340 can comprise a biodegradable material (e.g., hydrogel) having a plurality of pores containing the at least one substance, and the biodegradable material can be configured to degrade (e.g., dissolve) sometime after implantation, thereby releasing the at least one substance into the recipient’s tissue and / or bodily fluid after the assembly 310 has been implanted. For another example, the second portion 340 can be configured to selectively release the at least one substance in response to at least one of a temperature and a moisture content of the tissue and / or bodily fluid in which the assembly 310 has been implanted. The second portion 340 can have a sufficiently large surface area to release an efficacious amount of the at least one substance into the recipient’s body. Different portions of the second portion 340 can contain different substances.

[0058] In certain implementations, the at least one electrical conductor 330 (e.g., signal conduit) comprises one or more wires (e.g., platinum; platinum-iridium alloys; nickeltitanium alloys; nitenol). Each wire can have an outer diameter in a range of 0.01 millimeter to 1 millimeter (e.g., 0.02 millimeter; 0.05 millimeter) and an electrically insulating outer coating (e.g., plastic; paraylene; thermoplastic; polyphenylsulfone or PPSU) having a thickness in a range of 0.001 millimeter to 0.02 millimeter (e.g., 0.005 millimeter). Each electrical conductor 330 of the at least one electrical conductor 330 can have a helical shape and can extend along and within the at least one helical channel 324 encircling the longitudinal axis 322 (see, e.g., FIGs. 5A-5C). For example, as shown in FIGs. 5A-5C, the at least one helical channel 324 can comprise a single helical channel 324 and the at least one electrical conductor 330 can extend along and within the single helical channel 324. For another example in which the at least one helical channel 324 comprises a first helical channel having a first chirality and a second helical channel having a second chirality opposite to the first chirality (see, e.g., FIGs. 8A-8B), one or more of the electrical conductors 330 can extend along and within the first helical channel and can cross through the second helical channel. In certain such implementations, one or more of the electrical conductors 330 can extend along and within the second helical channel and can cross through the first helical channel (e.g., such that some electrical conductors 330 cross one another). In certain implementations, the first portion 320 can comprise at least one hole extending through the first portion 320 in a direction substantially perpendicular to the longitudinal axis 322. The at least one hole can be sized to have one or more electrical conductors 330 extend from a first side of the first portion 320 to a second side of the first portion 320. For example, one or more electrical conductors 330 can be wound with a first chirality around a first section of the first portion 320, can extend through the at least one hole, and can be wound with a second chirality around a second section of the first portion 320, the second chirality opposite to the first chirality. In certain implementations, the electrical conductors 330 can be parallel and not overlap one another (see, e.g., FIG. 5C), while in certain other implementations, at least one electrical conductor 330 can overlap another at least one electrical conductor 330. For example, an electrical conductor 330 can cross over another electrical conductor 330 with a non-zero angle between the electrical conductors 330. For another example, an electrical conductor 330 can overlay anotherelectrical conductor 330 with a substantially zero angle between the electrical conductors 330 (e.g., forming layers of helical windings).

[0059] In certain implementations, the at least one electrode 350 (e.g., electrical contact) comprises one or more electrically conductive layer (e.g., sheet; leaf; plate) having an outwardly facing surface 352 that is not covered by the second portion 340. The at least one electrode 350 can be affixed to an end portion 332 of the at least one electrical conductor 330 (e.g., joined; welded; soldered; epoxied; crimped) such that electrical stimulation signals can propagate along the at least one electrical conductor 330 to the at least one electrode 350 to the recipient’s body and / or electrical measurement signals can propagate from the at least one electrode 350 through the at least one electrical conductor 330 to circuitry (e.g., control circuitry) of the apparatus 300. In certain other implementations, the at least one electrode 350 can comprise a plurality of windings of a corresponding electrical conductor 330, the windings not having an electrically insulating outer coating.

[0060] The at least one electrode 350 can have a length Lein a direction substantially parallel to the longitudinal axis 322 (e.g., in a range of 0.2 millimeter to 4 millimeters), a width Wein a direction substantially perpendicular to the longitudinal axis 322 (e.g., in a range of 0.2 millimeter to 13 millimeters), and a thickness Tein a direction substantially perpendicular to the length Leand the width We(e.g., in a range of 0.01 millimeter to 1 millimeter). The at least one electrode 350 can extend around the longitudinal axis 322 by a polar angle in a range of 10 degrees to 360 degrees (e.g., in a range less than 180 degrees).

[0061] FIG. 5 A schematically illustrates an example assembly 310 in which the at least one electrode 350 comprises a single electrode 350 at a distal (e.g., apical) end portion of the assembly 310 (e.g., an end portion configured to be in operative communication with the recipient). The at least one electrical conductor 330 comprises a single electrical conductor 330 that extends from the electrode 350 towards a proximal end portion of the assembly 310 (e.g., an end portion configured to be in operative communication with other components of the apparatus 300).

[0062] FIGs. 5B and 5C schematically illustrate two example assemblies 310 in which the at least one electrode 350 comprises a plurality of electrodes 350 and the at least one electrical conductor 330 comprises a plurality of electrical conductors 330. For example, the at least one electrode 350 can comprise an array (e.g., two or more) of electrodes 350 (e.g.,array 146 of stimulation elements 148) distributed along the longitudinal axis 322 that, upon being in operational communication with a portion of the recipient’s body, can be configured to apply electrical stimulation signals to the portion of the recipient’s body (e.g., the cochlea 140) and / or to receive electrical measurement signals from the portion of the recipient’s body. The distance between adjacent electrodes 350 can in a range of 0.1 millimeter to 20 millimeters (e.g., in a range of 0.3 millimeter to 5 millimeters; in a range of 0.5 millimeter to 2 millimeters)

[0063] While FIGs. 5B and 5C show two electrodes 350 with two electrical conductors 330 and four electrodes 350 with four electrical conductors 330, respectively, other numbers of electrodes 350 and / or electrical conductors 330 are also compatible with certain implementations described herein (e.g., in a range of 2 to 10; in a range of 5 to 20; in a range of 15 to 25; in a range of 20 to 40; more than 40). In certain implementations, the electrodes 350 are positioned equidistantly from one another along the longitudinal axis 322 (see, e.g., FIG. 5C), while in certain other implementations, the distance between a first pair of adjacent electrodes 350 is different from the distance between a second pair of adjacent electrodes 350.

[0064] As shown in FIGs. 5B and 5C, the at least one electrical conductor 330 can comprise a first electrical conductor 330a and a second electrical conductor 330b extending substantially parallel to the first electrical conductor 330a, the second electrical conductor 330b electrically insulated from the first electrical conductor 330a. The at least one electrode 350 can comprise a first electrode 350a in electrical communication with the first electrical conductor 330a and a second electrode 350b in electrical communication with the second electrical conductor 330b. The first electrode 350a and the second electrode 350b can be spaced from one another along the longitudinal axis 322 (e.g., electrically insulated from one another) and the second electrode 350b can extend over a portion of the first electrical conductor 330a (e.g., with the second electrode 350b electrically insulated from the first electrical conductor 330a). As shown in FIG. 5C, the at least one electrical conductor 330 can further comprise a third electrical conductor 330c and a fourth electrical conductor 330d extending substantially parallel to the first electrical conductor 330a and electrically insulated from one another and from the first and second electrical conductors 330a, b. The at least one electrode 350 can further comprise a third electrode 350c in electrical communication with the third electrical conductor 330c and a fourth electrode 350d in electrical communication with the fourth electrical conductor 330d. The third and fourth electrodes 350c, d can be spacedfrom one another and from the first and second electrodes 350a, b along the longitudinal axis 322 (e.g., the first, second, third, and fourth electrodes 350a-d electrically insulated from one another), the third electrode 350c can extend over portions of the first and second electrical conductors 330a, b, and the fourth electrode 350d can extend over portions of the first, second, and third electrical conductors 330a-c (e.g., with the third and fourth electrodes 350c, d electrically insulated from the first and second electrical conductors 330a, b).

[0065] FIG. 9 is a flow diagram of an example method 400 in accordance with certain implementations described herein. FIGs. 10A-10C schematically illustrate an example assembly 310 (e.g., stimulation assembly of a cochlear implant that is configured to be at least partially inserted into a cochlea 140 of a recipient’s body) at various stages of fabrication in accordance with certain implementations described herein. While the method 400 is described by referring to some of the structures of the example assembly 310 described herein, other apparatus and systems with other configurations of components can also be used to perform the method 400 in accordance with certain implementations described herein.

[0066] In an operational block 410, the method 400 comprises accessing an elongate preform (e.g., first portion 320) comprising an electrically insulative and flexible first material and at least one spiral passage (e.g., at least one helical channel 324) having a plurality of loops encircling and distributed along a longitudinal axis (e.g., longitudinal axis 322) of the preform. For example, the preform can further comprise a plurality of protrusions (e.g., protrusions 326) distributed around and along the longitudinal axis, the plurality of protrusions at least partially bounding the at least one spiral passage. In certain implementations, accessing the elongate preform comprises forming the preform using injection molding (e.g., injected into a mold at one or more positions, cured, and removed from the mold). For example, the first material can be injection molded onto a reinforcement element (e.g., tensioned wire) configured to provide structural reinforcement (e.g., stiffness) and / or a predetermined shape (e.g., curved; straight) to the preform, the reinforcement element within (e.g., encased by; surrounded by) the preform.

[0067] In an operational block 420, the method 400 further comprises accessing a plurality of electrical wires (e.g., electrical conductors 330) each having a first end portion (e.g., first end portion 332) and a second end portion (e.g., configured to be in electrical communication with circuitry of the apparatus 300). In an operational block 430, the method400 further comprises winding the plurality of electrical wires around the preform within the at least one spiral passage such that first end portions of the plurality of electrical wires are spaced from one another along the longitudinal axis.

[0068] For example, as shown in FIG. 10A, a first electrical conductor 330a can be wound (e.g., wrapped) around the first portion 320 within the at least one helical channel 324, and a second electrical conductor 330b can be wound (e.g., wrapped) around the first portion 320 within the at least one helical channel 324 (e.g., substantially parallel to the first electrical conductor 330a). In certain implementations, the longest electrical conductor 330 is wound around the first portion 320 first, followed by winding the next-longest electrical conductor 330 around the first portion 320. The windings of the remaining electrical conductors 330 can continue in the order of lengths of the electrical conductors 330. In certain implementations in which the preform comprises a reinforcement element, the reinforcement element can facilitate keeping the preform straight while the electrical wires are wound around the preform.

[0069] While FIG. 10A shows the first and second conductors 330a, b wound around the first portion 320 before the electrodes 350a, b are affixed to the first end portions 332a, b, alternatively, the first and second conductors 330a, b can be wound around the first portion 320 after the electrodes 350a, b are affixed to the first end portions 332a, b. While FIG. 10A shows the first and second electrical conductors 330a, b wound within the same spiral passage portions (e.g., the first and second electrical conductors 330a, b not spaced from one another by at least some of the protrusions), alternatively, the first and second electrical conductors 330a, b can be wound within different spiral passage portions as one another (e.g., the first and second electrical conductors 330a, b spaced from one another by at least some of the protrusions. While FIG. 10A shows the first and second electrical conductors 330a, b wound with the same chirality as one another, alternatively, the first and second electrical conductors 330a, b can be wound with different (e.g., opposite) chiralities as one another.

[0070] In an operational block 440, the method 400 further comprises affixing a plurality of electrodes (e.g., electrodes 350) to the first end portions of the plurality of electrical wires. For example, each electrode of the plurality of electrodes can be affixed (e.g., joined; welded; soldered; epoxied; crimped) to a corresponding one of the plurality of electrical wires such that electrical signals can propagate along the electrical wires between the corresponding electrodes and circuitry of the apparatus 300.

[0071] In an operational block 450, the method 400 further comprises affixing the plurality of electrodes to the preform such that the plurality of electrodes are spaced from one another along the longitudinal axis. For example, as shown in FIG. 10B, the plurality of electrodes can be affixed (e.g., epoxied; crimped) to outer surfaces of the plurality of protrusions such that the plurality of electrodes extend over the at least one spiral passage. In certain implementations, affixing an electrode to the first end portion of the corresponding electrical wire is performed before affixing the electrode to the preform, while in certain other implementations, affixing the electrode to the first end portion of the corresponding electrical wire is performed after affixing the electrode to the preform.

[0072] In an operational block 460, the method 400 further comprises encasing the plurality of electrical wires within the at least one spiral passage. For example, an electrically insulative and flexible second material (e.g., comprising the first material; the same as the first material; different from the first material) can be injection molded over the plurality of electrical wires, the second material extending into the at least one spiral passage (e.g., between adjacent protrusions), as shown in FIG. 10C. The preform with the electrical wires can be placed within a cylindrical mold and the second material can be injected (e.g., at one or more positions) into the mold such that the second material flows throughout the length of the mold (e.g., the flow of the second material along the length is not blocked by the protrusions). After curing the second material, the preform, including the electrical wires and the second material, can be removed from the mold.

[0073] In certain implementations, the preform with the electrical wires and with the electrodes (see, e.g., FIG. 10B) is placed within the cylindrical mold (e.g., with the mold compressing the outer surfaces of the electrodes) such that the second material does not flow to cover the outer surfaces of the electrodes. In certain other implementations, the preform with the electrical wires is placed within the cylindrical mold without the electrodes being within the mold (e.g., before or after the electrodes have been affixed to the first end portions of the electrical wires) and the electrodes are affixed to the preform after curing the second material and removing the preform from the mold.

[0074] Although commonly used terms are used to describe the systems and methods of certain implementations for ease of understanding, these terms are used herein to have their broadest reasonable interpretations. Although various aspects of the disclosure aredescribed with regard to illustrative examples and implementations, the disclosed examples and implementations should not be construed as limiting. Conditional language, such as, among others, "can," "could," "might," or "may," unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain implementations include, while other implementations do not include, certain features, elements and / or steps. Thus, such conditional language is not generally intended to imply that features, elements and / or steps are in any way required for one or more implementations or that one or more implementations necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and / or steps are included or are to be performed in any particular implementation. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a nonexclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.

[0075] It is to be appreciated that the implementations disclosed herein are not mutually exclusive and may be combined with one another in various arrangements. In addition, although the disclosed methods and apparatuses have largely been described in the context of conventional cochlear implants, various implementations described herein can be incorporated in a variety of other suitable devices, methods, and contexts. More generally, as can be appreciated, certain implementations described herein can be used in a variety of implantable medical device contexts.

[0076] Language of degree, as used herein, such as the terms “approximately,” “about,” “generally,” and “substantially,” represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to an amount that is within ± 10% of, within ± 5% of, within ± 2% of, within ± 1 % of, or within ± 0.1% of the stated amount. As another example, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by ± 10 degrees, by ± 5 degrees, by ± 2 degrees, by ± 1 degree, or by ± 0.1 degree, and the terms “generally perpendicular” and “substantially perpendicular” refer to a value, amount, or characteristic that departs from exactly perpendicular by ± 10degrees, by ± 5 degrees, by ± 2 degrees, by ± 1 degree, or by ± 0.1 degree. The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” less than,” “between,” and the like includes the number recited. As used herein, the meaning of “a,” “an,” and “said” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “into” and “on,” unless the context clearly dictates otherwise.

[0077] While the methods and systems are discussed herein in terms of elements labeled by ordinal adjectives (e.g., first, second, etc.), the ordinal adjective are used merely as labels to distinguish one element from another (e.g., one signal from another or one circuit from one another), and the ordinal adjective is not used to denote an order of these elements or of their use.

[0078] The invention described and claimed herein is not to be limited in scope by the specific example implementations herein disclosed, since these implementations are intended as illustrations, and not limitations, of several aspects of the invention. Any equivalent implementations are intended to be within the scope of this invention. Indeed, various modifications of the invention in form and detail, in addition to those shown and described herein, will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the claims. The breadth and scope of the invention should not be limited by any of the example implementations disclosed herein, but should be defined only in accordance with the claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising: an assembly configured to be implanted on or within a recipient, the assembly comprising: a first portion having a longitudinal axis, the first portion comprising at least one helical channel having more than one 2TT- radian rotation around the longitudinal axis; at least one electrical conductor extending around the longitudinal axis within the at least one helical channel; a second portion extending over the first portion and within the at least one helical channel, the second portion covering at least a portion of the at least one electrical conductor; and at least one electrode in electrical communication with the at least one electrical conductor and configured to be in operative communication with a portion of the recipient.

2. The apparatus of claim 1, wherein the assembly further comprises at least one reinforcement element within the first portion and extending along and substantially parallel to the longitudinal axis.

3. The apparatus of claim 1 or claim 2, wherein the first portion comprises an electrically insulative and flexible first material and the second portion comprises an electrically insulative and flexible second material.

4. The apparatus of claim 3, wherein the first material comprises silicone and the second material comprises silicone.

5. The apparatus of any of claims 1 to 4, wherein the first portion comprises at least one helical protrusion having side surface portions that at least partially bound the at least one helical channel.

6. The apparatus of any of claims 1 to 4, wherein the first portion comprises a plurality of protrusions distributed along the longitudinal axis and having side surface portions that at least partially bound the at least one helical channel.

7. The apparatus of claim 6, wherein the at least one helical channel comprises a first helical channel having a first chirality and a second helical channel having a second chirality opposite to the first chirality.

8. The apparatus of claim 7, wherein the at least one electrical conductor extends along and within the first helical channel and crosses through the second helical channel.

9. The apparatus of any of claims 6 to 8, wherein the protrusions each have a first width in a first direction substantially parallel to the longitudinal axis and a second width in a second direction substantially perpendicular to the first direction.

10. The apparatus of claim 9, wherein the first width is greater than the second width.

11. The apparatus of claim 9, wherein the first width is substantially equal to the second width.

12. The apparatus of any of claims 1 to 11, wherein at least a portion of the at least one helical channel has a substantially constant pitch along the longitudinal axis.

13. The apparatus of any of claims 1 to 12, wherein at least a portion of the at least one helical channel has a varying pitch along the longitudinal axis.

14. The apparatus of any of claims 1 to 13, wherein the at least one electrode comprises an outwardly facing surface that is not covered by the second portion.

15. The apparatus of any of claims 1 to 14, wherein the at least one electrical conductor comprises a first electrical conductor and a second electrical conductor extending substantially parallel to the first electrical conductor, and the at least one electrode comprises a first electrode in electrical communication with the first electrical conductor and a second electrode in electrical communication with the second electrical conductor, the first electrode and the second electrode spaced from one another along the longitudinal axis, the second electrode extending over a portion of the first electrical conductor.

16. The apparatus of any of claims 1 to 15, wherein the assembly comprises a stimulation assembly of a cochlear implant, the assembly configured to be at least partially inserted into a cochlea of the recipient.

17. The apparatus of any of claims 1 to 16, wherein the first portions comprise holes that form at least one channel that is substantially parallel to the longitudinal axis.

18. A method comprising: accessing an elongate preform comprising: an electrically insulative and flexible first material; and at least one spiral passage having a plurality of loops encircling and distributed along a longitudinal axis of the preform; accessing a plurality of electrical wires each having a first end portion and a second end portion; winding the plurality of electrical wires around the preform within the at least one spiral passage such that first end portions of the plurality of electrical wires are spaced from one another along the longitudinal axis; affixing a plurality of electrodes to the first end portions of the plurality of electrical wires; affixing the plurality of electrodes to the preform such that the plurality of electrodes are spaced from one another along the longitudinal axis; and encasing the plurality of electrical wires within the at least one spiral passage.

19. The method of claim 18, wherein the preform further comprises a plurality of protrusions distributed around and along the longitudinal axis, the plurality of protrusions at least partially bounding the at least one spiral passage.

20. The method of claim 19, wherein affixing the plurality of electrodes to the preform comprises affixing the plurality of electrodes to outer surfaces of the plurality of protrusions such that the plurality of electrodes extend over the at least one spiral passage.

21. The method of any of claims 18 to 20, wherein accessing the preform comprises injection molding the first material onto a reinforcement element and encasing the plurality of electrical wires comprises injection molding an electrically insulative and flexible second material over the plurality of electrical wires, the second material extending into the at least one spiral passage.

22. The method of claim 21, wherein the second material comprises the first material.

23. An assembly comprising: a preform having a longitudinal axis, the preform comprising first regions extending a first distance substantially perpendicular to the longitudinal axis and second regions extending a second distance substantially perpendicular to the longitudinal axis, the second distance less than the first distance, the second regions forming at least one spiral passage around the longitudinal axis between the first regions; a plurality of electrical conduits, each electrical conduit comprising an electrically conductive wire wrapped around the longitudinal axis and within the at least one spiral passage and an electrode in electrical communication with the electrically conductive wire, the electrode having an outer surface facing away from the longitudinal axis; and an electrically insulating overlayer extending over the first and second regions, covering at least a portion of each electrical conduit while not covering at least a portion of the outer surface of the electrode of the electrical conduit.

24. The assembly of claim 23, wherein the preform further comprises a suture extending along and substantially parallel to the longitudinal axis.

25. The assembly of claim 23 or claim 24, wherein the preform has a substantially circular cross-section in a plane substantially perpendicular to the longitudinal axis, the first distance in a range of 0.3 millimeter to 2 millimeters, the second distance in a range of 0.3 millimeter to 2 millimeters, and a difference between the first distance and the second distance in a range of 0.2 millimeter to 1 millimeter.

26. The assembly of any of claims 23 to 25, wherein the at least one spiral passage has more than one 2TT- radian rotation around the longitudinal axis.

27. The assembly of any of claims 23 to 26, wherein the at least one spiral passage has more than 50 27t- radian rotations around the longitudinal axis.

28. The assembly of any of claims 23 to 27, wherein the first regions have a first width in a direction substantially parallel to the longitudinal axis, the first width in a range of 0.1 millimeter to 2 millimeters.

29. The assembly of any of claims 23 to 28, wherein the second regions have a second width in a direction substantially parallel to the longitudinal axis, the second width in a range of 0.1 millimeter to 2 millimeters.

30. The assembly of any of claims 23 to 29, wherein the at least one spiral passage has a pitch in a range of 0.1 millimeter to 4 millimeters.

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