Implantable electrode assembly with strain relief

Abstract

An apparatus includes at least one electrical conduit extending along a longitudinal axis and at least one electrode. The at least one electrode includes a portion configured to be in electrical communication with a portion of tissue and / or bodily fluid of a recipient. The at least one electrode further includes a flexure affixed to and in electrical communication with the at least one electrical conduit. The portion and the flexure are unitary with one another. The flexure is configured to flex in response to compressive and / or tensile forces applied to either the at least one electrical conduit or the at least one electrode

Description

COCLR.092WO PCT APPLICATIONIMPLANTABLE ELECTRODE ASSEMBLY WITH STRAIN RELIEFBACKGROUNDField

[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 / devices, 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 at least one electrical conduit extending along a longitudinal axis and at least one electrode. The at least one electrode comprises a portion configured to be in electrical communication with a portion of tissue and / or bodily fluid of a recipient. The at least one electrode further comprises a flexureaffixed to and in electrical communication with the at least one electrical conduit. The portion and the flexure are unitary with one another. The flexure is configured to flex in response to compressive and / or tensile forces applied to either the at least one electrical conduit or the at least one electrode.

[0005] In another aspect disclosed herein, an electrode array preform comprises an electrically conductive first portion extending along a longitudinal direction. The preform further comprises a plurality of electrically conductive second portions extending from and integral with the first portion and spaced from one another along the longitudinal direction. The preform further comprises a plurality of electrically conductive third portions. Each third portion extends from and integral with a respective second portion of the plurality of second portions and comprises one or more non-straight sections.

[0006] In another aspect disclosed herein, a method comprises accessing a preform. The preform comprises an electrically conductive spine extending along a longitudinal direction, a plurality of electrically conductive teeth extending from and integral with the spine and spaced from one another along the longitudinal direction, and a plurality of electrically conductive flexures. Each flexure extends from and is integral with a respective tooth of the plurality of teeth and comprises one or more curves and / or angles. The spine, the plurality of teeth, and the plurality of flexures are substantially planar with one another. The method further comprises plastically bending the plurality of flexures to extend substantially perpendicularly to the longitudinal direction. The method further comprises plastically bending the plurality of teeth in a direction substantially perpendicular to the longitudinal direction. The method further comprises securing, for each flexure of the plurality of flexures, a surface of the flexure to an end portion of a respective electrical wire.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-5G schematically illustrate perspective views of portions of various examples of an electrode array preform in accordance with certain implementations described herein;

[0013] FIGs. 6A-6H schematically illustrate perspective views of portions of an example preform at various stages during an example fabrication of an example apparatus in accordance with certain implementations described herein; and

[0014] FIG. 7 is a flow diagram of an example method in accordance with certain implementations described herein.DETAILED DESCRIPTION

[0015] Certain implementations described herein provide an electrode lead assembly comprising at least one electrode having an integral strain-relief element configured to be secured (e.g., affixed) to an end portion of a respective electrical conduit, the strain-relief element both (i) providing strain relief to the electrical conduit and (ii) providing a bonding surface (e.g., platform) to be secured to the end portion of the electrical conduit and to raise and control a position of the end portion to be at a neutral axis of the assembly, such that stresses applied to the bond between the electrical conduit and the strain-relief element when the electrode lead assembly is bent and / or straightened is reduced (e.g., minimized). A plurality of such electrodes can be manufactured to produce a comb-shaped preform substrate (e.g., sheet; see, e.g., U.S. Pat. No. 11,058,871) with electrodes that include integral strainrelief elements, bending of the strain-relief elements, and singulation of the electrodes from the preform.

[0016] 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.

[0017] 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, bone conduction 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.

[0018] 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 canalso 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).

[0019] 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 thecochlea 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.

[0020] 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. The sound 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).

[0021] 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 component144. During operation of the auditory prosthesis 100, the power stored by the rechargeable battery is distributed to the various other implanted components as needed.

[0022] 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.

[0023] 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 extend towards 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 cochl eostomy 122. In other circumstances, a cochl eostomy 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.

[0024] 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.

[0025] 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 (“HCI”). 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 (“MIQ”).

[0026] 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 stimulationassembly 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 cochl eostomy (e.g., formed through the oval window 112, the round window 121, the promontory 123, or through an apical turn of the cochlea 140).

[0027] 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 optical contacts (e.g., emitters) configured to apply optical stimulation, either alone or in conjunction with electrical or other stimulation mechanisms.

[0028] 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 thearray 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.

[0029] 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.

[0030] 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.

[0031] 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 ofspongy 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.

[0032] 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.

[0033] 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 the stimulating 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).

[0034] 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).

[0035] 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 cochl eostomy 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.

[0036] 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 distal end 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.

[0037] 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 moreresponsive 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).

[0038] 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).

[0039] 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 stimulationelements 148. In addition, the stimulation assembly 118 can experience twisting (e.g., rotation about the longitudinal axis) due to torsional forces (e.g., during insertion) which can move the stimulation elements 148 from predetermined implantation positions.

[0040] FIGs. 5A-5G schematically illustrate perspective views of portions of various examples of an electrode array preform 300 in accordance with certain implementations described herein. FIGs. 6A-6H schematically illustrate perspective views of portions of an example preform 300 at various stages during an example fabrication of an example apparatus 400 (e.g., electrode array 146; stimulation assembly 118; internal component 144) in accordance with certain implementations described herein. The apparatus 400 can be a stimulation assembly of a cochlear implant that is configured to be at least partially inserted into a cochlea 140 of a recipient’s body.

[0041] The preform 300 comprises an electrically conductive first portion 310 extending along a longitudinal direction 312. The preform 300 further comprises a plurality of electrically conductive second portions 320 extending from and integral with the first portion 310 and spaced from one another along the longitudinal direction 312. The preform 300 further comprises a plurality of electrically conductive third portions 330, each third portion 330 extending from and integral with a respective second portion 320 of the plurality of second portions 320 and comprising one or more non-straight (e.g., curved; angled) sections 332.

[0042] The apparatus 400 is configured to be implanted on or within a recipient and comprises at least one electrical conduit 402 extending along a longitudinal axis 404 and at least one electrode 410. The at least one electrode 410 comprises a portion 420 configured to be in electrical communication with a portion of tissue and / or bodily fluid of a recipient. The at least one electrode 410 further comprises a flexure 430 affixed to and in electrical communication with the at least one electrical conduit 402, and the portion 420 and the flexure 430 are unitary with one another. The flexure 430 is configured to flex in response to compressive and / or tensile forces applied to either the at least one electrical conduit 402 or the at least one electrode 410.

[0043] Each of FIGs. 5A-5C shows multiple second portions 320 and multiple respective third portions 330, and each of FIGs. 5D-5G shows a single second portion 320 with a single respective third portion 330. FIG. 5 A schematically illustrates a portion of an examplepreform 300 in an initial configuration (e.g., before any bending of the second portions 320 and / or the third portions 330), and each of FIGs. 5B-5G schematically illustrates portions of various example preforms 300 in a subsequent configuration (e.g., after plastic bending of the second portions 320 and / or the third portions 330 has occurred) during the fabrication of the apparatus 400. As shown in FIGs. 6A-6H, during fabrication, the preform 300 is used to form a plurality of electrodes 410, with the plurality of second portions 320 of the preform 300 becoming a plurality of portions 420 of the apparatus 400 and the plurality of third portions 330 of the preform 300 becoming a plurality of flexures 430 of the apparatus 400.

[0044] In certain implementations, the preform 300, including the first, second, and third portions 310, 320, 330, comprises an electrically conductive and biocompatible material, examples of which include but are not limited to: platinum; iridium; platinum-iridium alloy. The preform 300 can comprise a plurality of second portions 320 (e.g., the number of second portions 320 ranging from 2 to 300 or more, including 3, 4, 5, 6, 7, 8, 9, 10, 22, 10-20, 20-30, 30-50, 50-100, 100-150, 150-200, 200-256, 256-300). The total length of the preform 300 along the longitudinal direction 312 can be in a range of 5 mm to 50 mm (e.g., 5 mm to 15 mm; 10 mm to 30 mm) and can be sufficient to accommodate the number of second portions 320 and the respective third portions 330.

[0045] In certain implementations, each second portion 320 has a width W2 in a direction substantially parallel to the longitudinal direction 312 that is in a range of 0.1 mm to 1 mm (e.g., in a range of 0.2 mm to 0.3 mm) and / or has a length L2 in a direction substantially perpendicular to the longitudinal direction 312 that is in a range of 0.3 mm to 3 mm (e.g., in a range of 0.6 mm to 0.9 mm). Each second portion 320 can be spaced from a neighboring second portion 320 by a distance D2 in a direction substantially parallel to the longitudinal direction 312 that is in a range of 0.1 mm to 2 mm (e.g., in a range of 0.3 mm to 0.5 mm). Each third portion 330 can have a length L3 in a direction substantially parallel to the longitudinal direction 312 that is in a range of 60% to 95% of the distance D2 and / or can have a width Ws in a direction substantially perpendicular to the longitudinal direction 312 that is in a range of 0.1 mm to 0.3 mm.

[0046] In certain implementations, in the initial configuration, the preform 300 is substantially planar (e.g., the first portion 310, the plurality of second portions 320, and the plurality of third portions 330 are substantially planar with one another). Each second portion320 can extend away from the first portion 310 (e.g., in a direction substantially perpendicular to the longitudinal direction 312) and each third portion 330 can extend away from the respective second portion 320 (e.g., in a direction substantially parallel to the longitudinal direction 312) (see, e.g., FIGs. 5A, 6A, and 6B). For example, the preform 300 in the initial configuration can be fabricated by providing a substantially flat metal substrate 302 (e.g., sheet; ribbon) having a thickness Ti (e.g., in a range of 20 microns to 200 microns; 50 microns) and modifying (e.g., laser cutting, etching, or ablation; punching; pressing; stamping) the substrate 302 to have a comb-like shape with the second portions 320 extending from the first portion 310, and with each second portion 320 and respective third portion 330 spaced from an adjacent second portion 320 (see, e.g., FIGs. 5A, 6A, and 6B).

[0047] In certain implementations, each second portion 320 comprises a first surface 322 configured to be in electrical communication with a portion of the recipient’s tissue and / or bodily fluid and each third portion 330 comprises a second surface 334 (e.g., pad) configured to be secured (e.g., affixed) to a respective electrical conduit 402 (e.g., wire) of the apparatus 400 (e.g., electrode array). The first surface 322 and the second surface 334 can face in substantially opposite directions. The second surface 334 can have a substantially rectangular (e.g., square) shape (see, e.g., FIGs. 5A-5G) or can have another shape (e.g., circular; oval) and can have an area in a range of 0.05 mm x 0.05 mm to 0.5 mm x 0.5 mm (e.g., 0.1 mm x 0.1 mm). In certain implementations, the at least one electrical conduit 402 comprises one or more wires (e.g., platinum; platinum-iridium alloys; nickel-titanium 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).

[0048] In certain implementations, the thickness T2 of the second portions 320 and / or the thickness T3 of the third portions 330 in the initial configuration and in the subsequent configuration are substantially equal to the thickness Ti of the substrate 302. For example, as schematically illustrated by FIG. 5B, the thicknesses T2 and T3 in the subsequent configuration are both substantially equal to Ti. In certain other implementations, the thickness Ts of the third portions 330 varies across the third portion 330. For example, as schematically illustrated by FIG. 5C, the cutting of the substrate 302 to form the second portions 320 and / orthe third portions 330 can comprise thinning (e.g., via laser ablation, trimming, and / or pressing) portions 336 of the third portion 330 to have thicknesses that are less than the thickness Ti of the substrate 302. Such thickness modification can be performed to adjust the flexibility of the flexure 430 and the response of the flexure 430 to compressive and / or tensile forces applied to the electrode 410 and / or the electrical conduit 402 (e.g., applied to the second portion 320 and / or to the electrical conduit 402 secured to the second surface 334 of the third portion 330). In certain other implementations, the flexibility of the flexure 430 is controllab ly adjusted or tuned by selecting one or more physical dimensions of the flexure 430 (e.g., cross- sectional size and / or shape; overall shape; width, length, height, and / or angle of bending) and / or by applying one or more treatments to the flexure 430 (e.g., cutting and / or heat annealing).

[0049] In certain implementations, as schematically illustrated by FIGs. 5B-5G, the second portions 320 are bent such that a section of the first surface 322 of the second portion 320 is substantially parallel to the first portion 310. In addition, the third portions 330 can be bent such that a section of the second surface 334 of the third portions 330 is substantially parallel to the first portion 310. The second surface 334 of the third portion 330 can be positioned such that an interface (e.g., bond) between the third portion 330 (e.g., flexure 430) and the at least one electrical conduit 402 is at a neutral axis of the apparatus 400 (e.g., an axis along which longitudinal stresses or strains are equal to zero during bending of the apparatus 400 upon implantation). For example, the third portion 330 can comprise at least one bend (e.g., non-straight section 332) and can extend a distance Di in a direction substantially perpendicular to the first surface 322 of the second portion 320 (e.g., substantially perpendicular to the longitudinal direction 312 and / or the longitudinal axis 404), and the distance Di can be greater than the thickness Ti of the third portion 330.

[0050] In certain implementations (see, e.g., FIGs. 5B-5D and 6A-6B), the third portions 330 is substantially straight in the initial configuration (e.g., the third portions 330 in the initial configuration does not comprise the one or more non-straight sections 332), and is subsequently plastically bent to create the one or more non-straight sections 332 such that the third portions 330 comprise the one or more non-straight sections 332 in a subsequent configuration. For example (see, e.g., FIGs. 5B-5C and 6E), the third portion 330 can be substantially straight in the initial configuration and can be plastically bent to have two non-straight sections 332 such that the third portion 330 (e.g., flexure 430) extends the distance Di in a direction substantially perpendicular to the first portion 310 (e.g., substantially perpendicular to the longitudinal direction 312 and / or the longitudinal axis 404). For another example, the third portion 330 can be substantially straight in the initial configuration and can be plastically bent to have a single non-straight sections 332 that positions the second surface 334 over the second portion 320 (see, e.g., FIG. 5D).

[0051] In certain other implementations (see, e.g., FIGs. 5 A and 5E-5G), each third portion 330 can comprise one or more non-straight sections 332 (e.g., curves; angles) while the preform 300 is in the initial configuration (e.g., the one or more non-straight sections 332 are formed by the cutting of the substantially flat metal substrate 302) and can be subsequently modified (e.g., plastically bent) such that the third portion 330 (e.g., flexure 430) extends the distance Ds in a direction substantially perpendicular to the first portion 310 (e. g. , substantially perpendicular to the longitudinal direction 312 and / or the longitudinal axis 404). For example, each of the third portions 330 in the initial configuration can have a serpentine shape with multiple curves and / or angles (see, e.g., FIGs. 5A, 5G), can have a coil shape (see, e.g., FIG. 5E), or can have a pair of serpentine-shaped legs (see, e.g., FIG. 5F), and can be plastically bent during subsequent fabrication steps to displace the second surface 334 of the third portion 330.

[0052] In certain implementations, the apparatus 400 further comprises an insertion element (e.g., tube; sheath 260; stylet) in mechanical communication with the housing 406, the insertion element configured to implant the apparatus 400 within a region of the recipient’s body by inserting at least a portion of the insertion element into the region and sliding the housing 406 along the insertion element such that the housing 406 extends at least partially into the region. For example, the apparatus 400 comprising the insertion element and the housing 406 can be shipped and / or stored in a hermetically sealed container. After opening the container and removing the apparatus 400 from the container, the housing 406 can be implanted using the insertion element (see, e.g., FIGs. 4A-4F). After implanting the housing 406, the insertion element can be removed from the recipient’s body and discarded.

[0053] In certain implementations, the apparatus 400 is flexible and 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 apparatus 400 can besufficiently 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 apparatus 400 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 apparatus 400 can be sufficiently flexible such that at least a first portion of the apparatus 400 in mechanical communication with the insertion element has a first, substantially straight shape and during insertion, at least a second portion of the apparatus 400 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).

[0054] FIG. 7 is a flow diagram of an example method 500 in accordance with certain implementations described herein. While the method 500 is described by referring to some of the structures of the example preform 300 and the example apparatus 400 described herein, other apparatus and systems with other configurations of components can also be used to perform the method 500 in accordance with certain implementations described herein.

[0055] In an operational block 510, the method 500 comprises accessing a preform (e.g., preform 300) comprising an electrically conductive spine (e.g., first portion 310) extending along a longitudinal direction (e.g., longitudinal direction 312), a plurality of electrically conductive teeth (e.g., second portions 320), and a plurality of electrically conductive flexures (e.g., third portions 330) (see, e.g., FIGs. 6A-6B). The plurality of electrically conductive teeth extend from and are integral with the spine and are spaced from one another along the longitudinal direction. Each flexure of the plurality of electrically conductive flexures extends from and is integral with a respective tooth of the plurality of teeth and comprises one or more curves and / or angles. The spine, the plurality of teeth, and the plurality of flexures are substantially planar with one another.

[0056] In an operational block 520, the method 500 further comprises plastically bending the plurality of flexures to extend substantially perpendicularly to the longitudinal direction. In an operational block 530, the method 500 further comprises plastically bending the plurality of teeth in a direction substantially perpendicular to the longitudinal direction. Inan operational block 540, the method 500 further comprises securing (e.g., affixing), for each flexure of the plurality of flexures, a surface (e.g., second surface 334) of the flexure to an end portion of a respective electrical wire (e.g., electrical conduit 402).

[0057] In certain implementations, plastically bending the plurality of flexures is performed prior to plastically bending the plurality of teeth (see, e.g., FIG. 6C), while in certain other implementations, plastically bending the plurality of teeth is performed prior to plastically bending the plurality of flexures (see, e.g., FIG. 6D). In certain other implementations, plastically bending the plurality of flexures and plastically bending the plurality of teeth are performed concurrently with one another. As a result of plastically bending the plurality of teeth and / or plastically bending the plurality of flexures, the surface of the flexure to be secured to the end portion of a respective electrical wire is at a neutral axis of the resultant apparatus 400 upon implantation (see. e.g., FIG. 6E).

[0058] In certain implementations, the plurality of electrical wires comprise a first electrical conduit 402a and a second electrical conduit 402b extending substantially parallel to the first electrical conduit 402a. The first electrical conduit 402a can be affixed to and in electrical communication with a first electrode 410a and the second electrical conduit 402b can be affixed to and in electrical communication with a second electrode 410b, the first and second electrodes 410a, b spaced from one another along the longitudinal axis 404 (see, e.g., FIG. 6F). Examples of securing (e.g., affixing) a surface of the flexure (e.g., second surface 334 of the third portion 330) to an end portion of a respective electrical conduit 402 include but are not limited to: resistance welding, laser welding, soldering, gluing, crimping. In certain implementations, the process of securing the end portion of the electrical conduit 402 to the respective flexure is performed after plastically bending the flexure, while in certain other implementations, the process of securing the end portion of the electrical conduit 402 to the respective flexure is performed prior to plastically bending the flexure.

[0059] In certain implementations, the method 500 further comprises encasing the electrical wires and the flexures within an electrically insulative housing 406 (e.g., sheath), such that the housing 406 surrounds the electrical wires and the flexure of at least one electrode 410 (see, e.g., FIG. 6F). For example, the housing 406 can comprise a biocompatible and flexible material (e.g., silicone) that molded over the electrodes 410 and the electrical conduits 402. For each tooth of the plurality of teeth, an outer (e.g., outwardly facing) surface (e.g.,first surface 322) of the tooth is not covered by the housing 406, such that the outer surface can contact the recipient’s tissue and / or bodily fluid upon the apparatus 400 being implanted on or within the recipient’s body.

[0060] In certain implementations, the method 500 further comprises separating (e.g., singulating) the plurality of teeth from the spine. Separating the plurality of teeth from the spine can be performed after securing the surfaces of the flexures to end portions of the respective electrical wires and / or after encasing the electrical wires and the flexures within the housing 406 (see, e.g., FIG. 6G).

[0061] In certain implementations, the flexure 430 increases the flexibility of the electrode 410 in response to tensile forces and / or compressive forces applied to the electrode 410 and / or the respective electrical conduit 402 (e.g., during the fabrication and / or operation of the apparatus 400). For example, with the end portion of the respective electrical conduit 402 affixed to the second surface 334, the flexibility of the electrode 410 is greater than the flexibility that the electrode 410 would have with the end portion affixed to other portions of the electrode 410. The increased flexibility can be configured to protect the bond between the electrical conduit 402 and the electrode 410 from breakage and / or damage (e.g., open circuit between the electrical conduit 402 and the electrode 410), such that the electrical conduit 402 remains affixed to the electrode 410 upon larger tensile and / or compressive stresses being applied to the electrode 410 and / or the electrical conduit 402.

[0062] 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 are described 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 beperformed 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.

[0063] 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.

[0064] 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 ± 10 degrees, 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.

[0065] 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 aslabels 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.

[0066] 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: at least one electrical conduit extending along a longitudinal axis; and at least one electrode comprising: a portion configured to be in electrical communication with a portion of tissue and / or bodily fluid of a recipient; and a flexure affixed to and in electrical communication with the at least one electrical conduit, the portion and the flexure unitary with one another, the flexure configured to flex in response to compressive and / or tensile forces applied to either the at least one electrical conduit or the at least one electrode.

2. The apparatus of claim 1, wherein an interface between the flexure and the at least one electrical conduit is at a neutral axis of the apparatus.

3. The apparatus of claim 1 or claim 2, wherein the portion and the flexure comprise an electrically conductive and biocompatible material.

4. The apparatus of claim 3, wherein the electrically conductive and biocompatible material comprises platinum or platinum-iridium alloy.

5. The apparatus of any preceding claim, wherein the flexure has a serpentine shape.

6. The apparatus of any preceding claim, wherein the portion has a thickness in a direction substantially perpendicular to the longitudinal axis and the flexure comprises at least one bend and extends a distance in the direction, the distance greater than the thickness.

7. The apparatus of any preceding claim, further comprising an electrically insulative housing surrounding the at least one electrical conduit and the flexure of the at least one electrode.

8. The apparatus of claim 7, wherein the electrically insulative housing comprises silicone.

9. The apparatus of claim 7 or claim 8, wherein the portion comprises an outwardly facing surface that is not covered by the housing.

10. The apparatus of any preceding claim, wherein the at least one electrical conduit comprises a first electrical conduit and a second electrical conduit extending substantially parallel to the first electrical conduit, and the at least one electrode comprises a first electrodein electrical communication with the first electrical conduit and a second electrode in electrical communication with the second electrical conduit, the first electrode and the second electrode spaced from one another along the longitudinal axis.

11. The apparatus of any preceding claim, wherein the apparatus is a stimulation assembly of a cochlear implant, the stimulation assembly configured to be at least partially inserted into a cochlea of the recipient.

12. An electrode array preform comprising: an electrically conductive first portion extending along a longitudinal direction; a plurality of electrically conductive second portions extending from and integral with the first portion and spaced from one another along the longitudinal direction; and a plurality of electrically conductive third portions, each third portion extending from and integral with a respective second portion of the plurality of second portions and comprising one or more non-straight sections.

13. The preform of claim 12, wherein the first portion, the plurality of second portions, and the plurality of third portions are substantially planar with one another.

14. The preform of claim 12 or claim 13, wherein each second portion extends in a direction substantially perpendicular to the longitudinal direction and each third portion extends in a direction substantially parallel to the longitudinal direction.

15. The preform of any of claims 12 to 14, wherein each second portion comprises a first surface configured to be in electrical communication with a portion of tissue and / or bodily fluid of a recipient and each third portion comprises a second surface configured to be affixed to an electrical wire of an electrode array.

16. The preform of claim 15, wherein the first surface and the second surface face in substantially opposite directions.

17. A method comprising: accessing a preform comprising: an electrically conductive spine extending along a longitudinal direction;a plurality of electrically conductive teeth extending from and integral with the spine and spaced from one another along the longitudinal direction; and a plurality of electrically conductive flexures, each flexure extending from and integral with a respective tooth of the plurality of teeth and comprising one or more curves and / or angles, the spine, the plurality of teeth, and the plurality of flexures substantially planar with one another; plastically bending the plurality of flexures to extend substantially perpendicularly to the longitudinal direction; plastically bending the plurality of teeth in a direction substantially perpendicular to the longitudinal direction; and securing, for each flexure of the plurality of flexures, a surface of the flexure to an end portion of a respective electrical wire.

18. The method of claim 17, further comprising encasing the electrical wires and the flexures within an electrically insulative sheath.

19. The method of claim 18, wherein the electrically insulative sheath comprises silicone.

20. The method of claim 18 or claim 19, wherein, for each tooth of the plurality of teeth, an outer surface is not covered by the sheath.

21. The method of any of claims 17 to 20, wherein plastically bending the plurality of flexures and plastically bending the plurality of teeth are performed concurrently with one another.

22. The method of any of claims 17 to 20, wherein plastically bending the plurality of flexures is performed prior to plastically bending the plurality of teeth.

23. The method of any of claims 17 to 20, wherein plastically bending the plurality of teeth is performed prior to plastically bending the plurality of flexures.

24. The method of any of claims 17 to 23, wherein plastically bending the plurality of teeth and / or plastically bending the plurality of flexures positions the surface of the flexure at a neutral axis.

25. The method of any of claims 17 to 24, wherein said securing is performed after said plastically bending the plurality of flexures.

26. The method of any of claims 17 to 25, further comprising separating the plurality of teeth from the spine after said securing.

27. The method of claim 26, wherein said separating is performed after said securing.

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