Patent Description:
The types of implantable medical devices and the ranges of functions performed thereby have increased over the years. For example, many 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, the implantable medical device. <CIT> discloses an elongate implantable carrier member having an embedded stiffener. <CIT> discloses a flexible implantable electrode assembly for a stimulating medical device.

Aspects, embodiments and examples of the present disclosure which do not fall under the scope of the appended claims do not form part of the invention and are merely provided for illustrative purposes.

In an example, there is an apparatus having: a flexible elongate carrier having a proximal region and being configured to introduce a therapeutic element into a recipient; and a stabilizer permanently embedded in and longitudinally extending through at least the proximal region. The stabilizer is configured to decrease flexibility of the proximal region so as to resist deformation of the proximal region during introduction of the flexible elongate carrier into the recipient. The stabilizer comprises an elastomeric material.

In another example, there is a flexible elongate carrier for introducing a therapeutic element into a recipient. The flexible elongate carrier includes a first elastomeric body material having a first hardness and a stabilizer extending through at least a portion of the first elastomeric body material. The stabilizer includes a second elastomeric body material having a second hardness greater than the first hardness.

In yet another example, there is a method comprising: forming a carrier at least partially from a first elastomeric body material having a first hardness; and disposing a stabilizer in at least a portion of the carrier. The stabilizer is at least partially formed from a second elastomeric body material having a second hardness greater than the first hardness.

The same number represents the same element or same type of element in all drawings.

Examples disclosed herein include example apparatuses and methods for facilitating the temporary or permanent implantation of one or more therapeutic elements into a patient. For ease of understanding, many examples herein are described below in the context of cochlear implants with the therapeutic elements being electrodes. Cochlear implants use direct electrical stimulation of auditory nerve cells to bypass absent or defective hair cells that normally transduce acoustic vibrations into neural activity. The electrodes are inserted into the scala tympani of the cochlea so that the electrodes can differentially activate auditory neurons that normally encode differential pitches of sound. Such devices are also used to treat a smaller number of patients with bilateral degeneration of the auditory nerve. For such patients, the cochlear implant provides stimulation of the cochlear nucleus in the brainstem.

Examples herein can be used in conjunction with a cochlear implant, such as a CONTOUR, FREEDOM, NUCLEUS, or COCHLEAR implant sold by COCHLEAR LIMITED, Australia. Example cochlear implants are described in <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>. It should be understood to those of ordinary skill in the art that examples disclosed herein can be used in other medical devices. Such medical devices can include, for example, prosthetic hearing implants, neurostimulators, cardiac pacemakers, cardiac defibrillators, sleep apnea management stimulators, seizure therapy stimulators, vestibular implants, and bionic eyes, as well as other medical devices that utilize an elongate carrier to temporarily or permanently implant, deliver or otherwise introduce a therapeutic element (e.g., an inert agent, a pharmacological agent, a sensor, a device, or an electrode) into a recipient.

In many examples, the flexibility of therapeutic element assemblies can beneficially minimize trauma to anatomical structures during insertion. But therapeutic element assemblies that are too flexible can be prone to buckling during insertion. For example, within the cochlear implant context, without sufficient stiffness the electrode assembly (the therapeutic element assembly of a cochlear implant) can be too soft and flexible to allow insertion to <NUM> degrees and beyond. Some approaches to having sufficiently flexible electrode assemblies include the use of tapering to progressively increase the cross section of the electrode assembly towards the basal end. Other approaches include the use of a stiffener embedded in the electrode assembly, which allows the cross section and volume (and therefore disturbance to anatomical structures and fluid pressure) of the electrode assembly to be reduced.

As a specific example, electrode assemblies of cochlear implants (e.g., the COCHLEAR NUCLEUS CI422, COCHLEAR NUCLEUS CI522, or COCHLEAR NUCLEUS HYBRID L) can incorporate a basal platinum stiffening member. Such stiffeners are tapered and annealed to minimize sudden changes in stiffness along the length of the array. However the relative stiffness of platinum compared to the silicone of the electrode assembly is high compared to metal stiffeners, disclosed examples can provide better control over the distribution of stiffness along the electrode assembly and have improved durability due to the tendency of example stabilizers herein to elastically (rather than plastically) deform.

Examples disclosed herein include the use of an elastomeric region (e.g., made of silicone) having a greater hardness than the silicone of the therapeutic element assembly to provide stiffness. The stabilizer can be configured to provide stiffness to the therapeutic element assembly while having a smaller change in relative stiffness with the rest of the assembly compared to traditional stiffeners. The elastomeric region can be referred to as a stabilizer and can have one or more of any of a variety of characteristics. For example, the stabilizer can be made of a single grade or multiple grades of elastomers of increasing durometer from the distal to proximal end of the stabilizer. The stabilizer can be separately molded and then encapsulated in the therapeutic element assembly during a final molding process. The stabilizer can be formed by molding the therapeutic element assembly with a lumen or internal hollow space that is post-filled with liquid elastomer (e.g., silicone) then cured. The stabilizer can be tapered to provide smooth grading of stiffness. The stabilizer can have features such as holes or grooves to promote bending at desired locations (e.g., to facilitate insertion). The stabilizer can have holes or other features to provide positive mechanical integration with the body material (e.g., silicone) of the carrier of the therapeutic element assembly. The stabilizer can be continuous with a handle. The stabilizer can itself be stiffened by a metallic or other element embedded in its proximal region (e.g., outside the cochlea). For example, a metallic stiffener can be disposed within the stabilizer without extending distally past the collar. Such a stiffener can provide further stiffness and stabilization with the handle. This metallic element may extend into the lead to produce a malleable lead to prevent springing during fixation. The stabilizer can be molded with bumps or other protrusions to center the stabilizer within a molding die while still being largely encapsulated by the carrier. Where the stabilizer is used with cochlear implants, the stabilizer can continue basally outside the intracochlear region to provide stability and prevent buckling/hinging outside the cochlea.

Beneficially, the stabilizer can tune the bending stiffness of the carrier of the therapeutic element assembly to vary along the length of the carrier without points of substantial discontinuity in stiffness. With metallic stiffeners, due to the very large difference in material properties between even the softest metal and the elastomer material of the therapeutic element assembly, there can be a step change in bending stiffness at the end of the metallic stiffener. By contrast, with a stabilizer that is made of similar material to the surrounding material (e.g., the material of the therapeutic element assembly that surrounds the stiffener), it is possible to more gradually vary the stiffness along the length of the therapeutic element assembly. For instance the stabilizer can be made from the same material as the body of the therapeutic element assembly but with increased hardness (e.g., both can be made from silicone, but the stabilizer can be made from a harder silicone).

The elastomeric stabilizer element can further advantageously elastically deform if bent. By contrast, a metallic stiffener tends to plastically deform if accidentally bent or buckled during manufacturing or surgery (e.g., before or during insertion). While the therapeutic element assembly can be manually re-straightened, the points at which the stiffener bent would retain residual stress, and act as weak points at which buckling is likely to occur during insertion. By contrast, the elastomeric stabilizers disclosed herein can be configured to elastically deform if accidentally bent or buckled during manufacturing or in surgery. While the electrode wires within the array (e.g., which may be made of platinum or an alloy) may still kink during bending, the presence of the elastomeric stiffener tends to support the array at these locations and minimizes risk of repeat buckling, and also produce a smoother, more distributed pattern of contact pressure with the lateral wall during insertion.

A further advantage is in manufacturability. An elastomeric stabilizer can be molded to almost any shape very with high repeatability. By contrast, a metal stiffener, which must typically be tapered in order to minimize sudden changes in stiffness, can be relatively difficult to manufacture due to the tight tolerances required. Geometry is generally also constrained by manufacturing considerations. For example, a metallic element may be tapered in one direction by a forming or grinding process, however tapering in a second plane requires a second processing step which adds cost and complexity. The material generally used for the stiffener is platinum, due to its biocompatibility and malleability, making the stiffener a significant factor in the overall cost of the electrode. By contrast, the stabilizers disclosed herein can be formed from an elastomer in a single forming process (e.g., as compared to the multiple processing steps required to form a metallic stiffener). Further, where the stabilizer is formed from an elastomer, the stabilizer <NUM> is non-conductive, so the carrier can be manufactured without the need for insulation to prevent contact between the wires running through the carrier and a metallic stiffener.

An example medical device that can benefit from the stabilizer technology disclosed herein is shown in <FIG>.

Medical devices can benefit from stabilizers disclosed herein, particularly medical devices having a therapeutic element assembly that is inserted into a target region of a recipient. For example, stabilizers disclosed herein can facilitate insertion of an electrode array into a cochlea of a recipient.

<FIG> illustrates a cochlear implant and a cut-away view of the relevant components of an outer ear <NUM>, a middle ear <NUM>, and an inner ear <NUM>. In a fully functional ear, the outer ear <NUM> comprises an auricle <NUM> and an ear canal <NUM>. The auricle collects acoustic waves <NUM> and channels the acoustic waves into and through the ear canal <NUM>. Disposed across the distal end of the ear canal <NUM> is a tympanic membrane <NUM> that vibrates in response to the acoustic waves <NUM>. This vibration is coupled to the oval window <NUM> through the ossicles <NUM> of the middle ear <NUM>. The ossicles <NUM> are bones of the middle ear <NUM> and include the malleus <NUM>, the incus <NUM> and the stapes <NUM>. The ossicles <NUM> serve to filter and amplify the acoustic waves <NUM> and to cause the oval window <NUM> to vibrate. Such vibration sets up waves of fluid motion within the cochlea <NUM>. Such fluid motion, in turn, activates tiny hair cells (not shown) that line the inside of the cochlea <NUM>. Activation of the hair cells causes appropriate nerve impulses to be transferred through the spiral ganglion cells and the auditory nerve <NUM> to the brain (not shown), where they are perceived as sound. In people experiencing sensorineural hearing loss, there is an absence or destruction of the hair cells. A cochlear implant can be used to directly stimulate the spinal ganglion cells to provide a hearing sensation to such people.

<FIG> further shows how the cochlear implant <NUM> is positioned in relation to the outer ear <NUM>, the middle ear <NUM>, and the inner ear <NUM>. The cochlear implant <NUM> has an external assembly <NUM> that is directly or indirectly attached to the body of the recipient, and an internal component assembly <NUM> that is temporarily or permanently implanted in the recipient. The external assembly <NUM> has a microphone <NUM> for detecting sound that is outputted to a behind-the-ear speech processing unit <NUM>. During use, the microphone <NUM> can be worn on the recipient's pinna or another suitable location, such as a lapel of the recipient's clothing. The speech processing unit <NUM> can generate coded signals that are provided to an external transmitter unit <NUM>, along with power from a power source such as a battery.

The external transmitter unit <NUM> includes an external coil <NUM> and, preferably, a magnet (not shown) secured directly or indirectly in the external coil <NUM>. The internal components include an internal receiver/transmitter unit having an internal coil (not shown) that receives and transmits power and coded signals from the external assembly <NUM> to a stimulator <NUM> to apply the coded signal along a therapeutic element assembly <NUM>. The therapeutic element assembly <NUM> enters the cochlea <NUM> at a cochleostomy region <NUM> and has one or more of the electrodes <NUM> positioned to be substantially aligned with tonotopically-mapped portions of the cochlea <NUM>. Signals generated by the stimulator <NUM> are applied by the electrodes <NUM> of the electrode array <NUM> to the cochlea <NUM>, thereby stimulating the auditory nerve <NUM>. It should be appreciated that although in the embodiment shown in <FIG> electrodes <NUM> are arranged in an electrode array <NUM>, other arrangements are possible.

The therapeutic element assembly <NUM> can be configured to assume an optimal electrode position in the cochlea <NUM> upon or immediately following implantation into the cochlea <NUM>. It is also desirable that the therapeutic element assembly <NUM> be configured such that the insertion process causes minimal trauma to the sensitive structures of the cochlea <NUM>. Usually a therapeutic element assembly is held in a straight configuration at least during the initial stages of the insertion procedure, then conforming to the natural shape of the cochlea during and subsequent to implantation.

While cochlear implant system <NUM> is described as having external components, in another embodiment, one or more components can be implantable. In such embodiments, a controller can be contained in a hermetically sealed housing or the housing of the stimulator <NUM>.

While <FIG> illustrates a cochlear implant <NUM> that can benefit from technologies disclosed herein, other devices and systems can benefit from disclosed technologies. For instance, the technology can be used in conjunction with any apparatuses having a flexible elongate carrier configured to introduce a therapeutic element into a recipient. For instance, disclosed technology can be used to insert therapeutic elements of any of a variety of sensory prostheses. For example, the sensory prosthesis can be a prosthesis relating to one or more of the five traditional senses (vision, hearing, touch, taste, and smell) and/or one or more of the additional senses. As described above, a sensory prosthesis can be an auditory prosthesis medical device (e.g., a cochlear implant <NUM>) configured to treat a hearing-impairment of the recipient. Where the sensory prosthesis is an auditory prosthesis, the sensory prosthesis can take a variety of forms including a cochlear implant, an electroacoustic device, a middle ear device, a totally-implantable auditory device, a mostly-implantable auditory device, an auditory brainstem implant device, other auditory prostheses, and combinations of the foregoing (e.g., binaural systems that include a prosthesis for a first ear of a recipient and a prosthesis of a same or different type for the second ear). In examples, the sensory prosthesis can be or include features relating to bionic eyes. Technology disclosed herein can also be relevant to applications with devices and systems used in for example, sleep apnea management, tinnitus management, and seizure therapy. Technology disclosed herein can be used with sensory devices such as consumer auditory devices (e.g., a hearing aid or a personal sound amplification product. Generally, disclosed examples replace or supplement one or more components of a therapeutic element assembly.

<FIG> is made up of <FIG>. <FIG> illustrates a side view of an example therapeutic element assembly <NUM> in accordance with certain embodiments of the invention. <FIG> illustrates a detail view of a portion of the therapeutic element assembly <NUM> of <FIG>. <FIG> illustrates a cross-section view of a portion of the therapeutic element assembly <NUM> of <FIG> taken along the line C-C. <FIG> illustrates a cross-section view of a portion of the therapeutic element assembly <NUM> at or proximate a most-proximal therapeutic element <NUM>. <FIG> illustrates a cross-section view of a portion of the therapeutic element assembly <NUM> of <FIG> taken along the line D-D. <FIG> illustrates a cross-section view of a portion of the therapeutic element assembly <NUM> at or proximate a distal-most therapeutic element <NUM> before the distal end of the stabilizer <NUM> (e.g., the distal-most section of the therapeutic element assembly <NUM> having both a therapeutic element <NUM> and the stabilizer <NUM>). <FIG> illustrates a cross-section view of the therapeutic element assembly <NUM> of <FIG> taken along the line E-E. <FIG> illustrates a cross-section view of a portion of the therapeutic element assembly <NUM> at or proximate a distal-most therapeutic element <NUM> of the therapeutic element assembly <NUM>.

The therapeutic element assembly <NUM> includes a carrier <NUM>. The carrier <NUM> can be the portion of the therapeutic element assembly <NUM> that holds the therapeutic elements <NUM>. The carrier <NUM> can be configured to be inserted into a treatment site and appropriately position the therapeutic elements <NUM> proximate a region to be treated. The carrier <NUM> has a distal region <NUM> and a proximal region <NUM> connected to the collar <NUM>. In some examples, the therapeutic element assembly includes a collar <NUM>, a handle <NUM>, and a lead <NUM>. The proximal end of collar <NUM> is connected to the handle <NUM>.

It should be understood that the terms medial surface, medial direction and the like are generally used herein to refer to the surfaces, features and directions toward a treatment site (e.g., toward the center of a cochlea), while the terms lateral surface, lateral direction and the like are generally used herein to refer to surfaces, features and directions away from the treatment site (e.g., toward the exterior of the cochlea). For example, where the therapeutic element assembly <NUM> is for a cochlear implant, the longitudinally-extending surface of the carrier <NUM> that faces the interior of cochlea <NUM> when implanted can be referred to as a medial surface <NUM> of the carrier <NUM>. The opposing side of the carrier <NUM> that faces the external wall and bony capsule of cochlea <NUM> when implanted can be referred to as a lateral surface <NUM>.

A plurality of spaced-apart therapeutic elements <NUM> are mounted on or in the carrier <NUM>. For ease of understanding, the therapeutic elements <NUM> are referred to herein as electrodes <NUM>, but, as discussed above, any of a variety of one or more therapeutic elements can be used instead of or in addition to electrodes. The electrodes <NUM> can be disposed in a linear or non-linear array on or in the carrier <NUM>, and may be positioned to align with predetermined tonotopically-mapped regions of the cochlea <NUM>. In one alternative embodiment, the electrodes <NUM> have variable spacing as described in <CIT>, which is titled "Flexible Electrode Assembly Having Variable Pitch Electrodes". Such arrangements allow for individual electrodes <NUM> to be energized to stimulate selected regions of the cochlea <NUM>.

In one example, the electrodes <NUM> are half-band electrodes disposed on the medial surface <NUM> of the carrier <NUM>. It should be appreciated, however, that any electrodes <NUM> now or later developed suitable for a particular application or therapeutic objective may be used in alternative embodiments. For example, in one alternative embodiment, the electrodes <NUM> are banded electrodes extending substantially around the carrier <NUM>. In another alternative embodiment, the electrodes <NUM> do not laterally extend to or around the edges of the carrier <NUM>.

In many examples, each of the electrodes <NUM> is arranged orthogonal to a longitudinal axis <NUM> of the carrier <NUM>. But other relative positions and orientations may be implemented in alternative embodiments. Further, the quantity of the electrodes <NUM> can vary from as few as one electrode to as many as twenty-four or more electrodes. In some examples, at least one of the electrodes <NUM> has a surface that is at least adjacent the medial surface <NUM> of the carrier <NUM>. One or more of the electrodes <NUM> can have a surface that is co-located with the medial surface <NUM> of the carrier <NUM>. In another example, the surfaces of the electrodes <NUM> are raised above or recessed into the medial surface <NUM> of the carrier <NUM>. The electrodes <NUM> can be manufactured from a biocompatible conductive material such as platinum, but other materials or combinations of materials can be used. In other examples, the electrodes <NUM> can be coated with a biocompatible covering that does not substantially interfere with the transfer of the stimulation signals to the cochlea <NUM>.

As can be seen in <FIG>, each electrode <NUM> can be electrically-connected to at least one wire <NUM>. Each wire <NUM> can be a multi- or single-filament wire that is embedded within the flexible carrier <NUM>, collar <NUM>, handle <NUM>, and lead <NUM>. The wires <NUM> are embedded in the volumetric core of carrier <NUM>. In collar <NUM>, the stabilizer <NUM> and the wires <NUM> extend or travel through a central volumetric core. In an alternative example, the wires <NUM> can be located at or near the medial surface <NUM> or the lateral surface <NUM> of the carrier <NUM>. In other embodiments, the wires <NUM> are embedded in different regions of the carrier <NUM> to facilitate attainment of a desired curvature, to maintain orientation of the carrier <NUM> once the carrier <NUM> is implanted, to attain a desired level of isolation between the stabilizer <NUM> and the wires <NUM>, to achieve other objectives, or combinations thereof. The stimulator <NUM> can provide electrical stimuli to the electrodes <NUM> via the wires <NUM>. In one embodiment, the wires <NUM> are connected to the electrodes <NUM> by welding or another suitable connecting technique.

The number of wires <NUM> connected to each of the electrodes <NUM> may vary. For example, in one example, at least two electrically conducting wires <NUM> are connected to each of one or more electrodes <NUM>. It should also be appreciated that suitable transmission means other than filament wires may be used to communicably couple the stimulator <NUM> and the electrodes <NUM>.

In the illustrated example, a lead <NUM> longitudinally extends through the carrier <NUM>, collar <NUM> and the handle <NUM> to electrically connect the electrodes <NUM> with a device, such as the stimulator <NUM> of <FIG>. In an example, the lead <NUM> can be about <NUM> long. The lead <NUM> can include a bundle of wires running from the electrodes.

The stimulator <NUM> can be encased within a housing that is implantable within the recipient. Where the stimulator <NUM> is for a cochlear implant, the housing can be implantable within a recess in bone behind the ear posterior to the mastoid. In one example, the lead <NUM> extends from the handle <NUM> to the stimulator <NUM> (or the housing of stimulator <NUM>). In one particular embodiment, the lead <NUM> is continuous (e.g., with no electrical connectors required to electrically connect the therapeutic element assembly <NUM> to the stimulator <NUM>). One advantage of this arrangement is that there is no requirement for a surgeon implanting the therapeutic element assembly <NUM> to make the necessary electrical connection between the wires <NUM> extending from the electrodes <NUM> and the stimulator <NUM>.

The handle <NUM> is a portion by which the surgeon implanting the therapeutic element assembly <NUM> can grasp and manipulate the therapeutic element assembly <NUM>. In some examples, the handle <NUM> provides for improved handling and the ability to identify electrode orientation. In some examples, the handle <NUM> can be configured as described in <CIT>. The stabilizer <NUM> can be disposed in the handle, which can ease the manufacturing process and reduce or eliminate the need for an additional stiffener for the handle to be constructed and added. The inside of the handle <NUM> can have features to improve flow of material used to form the stabilizer <NUM> during manufacture. For example, the features can include one or more wings, bumps, ridges, channels, other features, or combinations thereof configured to enhance or inhibit the flow of material during manufacture.

In some examples, the distal region <NUM> of the carrier <NUM> is profiled. The profile can help guide the carrier <NUM> during the insertion process, such as by reducing friction. Alternative embodiments of the distal region <NUM> are described in <CIT>. In other examples, the distal region <NUM> can be as described in <CIT>.

In some examples, the therapeutic element assembly can include a collar <NUM>. The collar <NUM> can serve as both a region for grasping the therapeutic element assembly <NUM> and also act to prevent insertion of the carrier <NUM> beyond a predetermined maximum depth to reduce the risk of the surgeon over-inserting the therapeutic element assembly <NUM>, which could otherwise cause trauma to anatomical structures. In certain examples, the predetermined maximum depth is as described in the above-referenced applications or in <CIT>; <CIT>; and <CIT>. The collar <NUM> is described in further detail in the above applications.

As illustrated, the carrier <NUM> includes a stabilizer <NUM>. The stabilizer <NUM> can be permanently embedded in at least the proximal region <NUM> of the carrier <NUM>. In such examples, the stabilizer <NUM> cannot be removed from the carrier <NUM> without damaging one or both of the carrier <NUM> or the stabilizer <NUM>. In the illustrated example in <FIG> and <FIG>, the stabilizer <NUM> can extend from an external portion (e.g., an extracochlear region) of the therapeutic element assembly <NUM> through the collar <NUM> and into the carrier <NUM>. In alternative embodiments, the stabilizer <NUM> need not be embedded in the collar <NUM>, and the stabilizer <NUM> can longitudinally extend further through carrier <NUM> to terminate at any desired location along the length of carrier <NUM>. Where the therapeutic element assembly <NUM> is configured for use with a cochlear implant, the stabilizer <NUM> can extend into the carrier <NUM> such that the stabilizer <NUM> terminates just before the lateral wall of the first turn of the cochlea <NUM> when the carrier <NUM> is completely inserted into the cochlea <NUM>.

The stabilizer <NUM> can be configured to increase the stiffness of the carrier <NUM> in the regions in which stabilizer <NUM> is located. As such, stabilizer <NUM> assists in the prevention of buckling or deformation of the carrier <NUM> in such regions during insertion of the carrier <NUM> into the cochlea <NUM>. In particular, the stabilizer <NUM> assists in maintaining the proximal region <NUM> of carrier <NUM> in a sufficiently-straight configuration when subjected to the forces typically experienced during implantation. This allows the carrier <NUM> and the electrodes <NUM> to be fully implanted into cochlea <NUM> without being subject to insertion forces that may damage the delicate structures of the cochlea.

Additionally, the stabilizer <NUM> can be configured to cause the electrodes <NUM> to be positioned closer to a treatment site (e.g., the inner wall of the cochlea <NUM>) because a straight carrier <NUM> may generally take a more lateral position (e.g., in the basal region of the cochlea <NUM>). As a result, the distance from the stimulating surface of carrier <NUM> to treatment site (e.g., the auditory nerve endings proximate the treatment site) is substantially less than would be the case if the stabilizer <NUM> were not embedded in the therapeutic element assembly <NUM>. The stabilizer <NUM> can provide similar benefits to cochlear implants in the basal region as a perimodiolar electrode (e.g., the perimodiolar electrode described in <CIT>). While many examples herein describe the material of the stabilizer <NUM> as having a stiffness greater than that of the material of the carrier <NUM>, It should also be appreciated that the stiffness of the material of the stabilizer <NUM> may be less than, the same as, or greater than the stiffness of the carrier <NUM>, so long as the presence of stabilizer <NUM> in regions of carrier <NUM> results in at least one of such regions having a reduced likelihood of deformation.

The stabilizer <NUM> can be formed from or otherwise comprise an elastomeric material. The elastomeric material can be a medical grade elastomeric material. The elastomeric material can be a silicone elastomer. In an example, the silicone elastomer has a hardness of <NUM> Shore A hardness units. For instance, the silicone elastomer can be made from MED-<NUM> silicone rubber produced by NUSIL TECHNOLOGY LLC. The silicone elastomer can have a tensile strength of <NUM> PSI, an elongation of <NUM>%, and a tear resistance of <NUM> PPI.

The stabilizer <NUM> can be constructed from an elastomeric body material that is different from the elastomeric body material of the carrier <NUM>. For example, the carrier <NUM> can be manufactured using a first elastomeric body material having a first hardness. The stabilizer <NUM> can extend through at least a portion of the first elastomeric body material and be manufactured using a second elastomeric body material. The second elastomeric body material can have a second hardness greater than the first hardness. In an example, the stabilizer <NUM> can be formed from a material having a hardness that is <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% harder than the material from which the carrier <NUM> is constructed. In another example, the difference in hardness between material of the stabilizer <NUM> and the material of the carrier <NUM> can be less than <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% of the hardness of the material from which the carrier <NUM> is constructed. As a specific example, the carrier <NUM> can be constructed from a silicone elastomer having a hardness of <NUM> Shore A hardness units (e.g., MED-<NUM> silicone rubber produced by NUSIL TECHNOLOGY LLC). In such an example, the stabilizer <NUM> can be constructed from a silicone elastomer having a hardness of <NUM> Shore A hardness units. In such an example, the material from which the stabilizer <NUM> is constructed has a hardness that is approximately one-third greater than the hardness of the carrier <NUM> (i.e., <NUM> Shore A hardness units harder). In another example, the hardness of the carrier <NUM> is less than or equal to <NUM> durometer type A hardness, and the hardness of the stabilizer <NUM> is greater than the first hardness and less than or equal to <NUM> durometer type A hardness.

The stabilizer <NUM> can be configured to variably decrease the flexibility of one or more regions of the carrier <NUM> (e.g., the proximal region <NUM>). For example, the stabilizer <NUM> can have a tapered profile, thereby variably decreasing the flexibility of the proximal region <NUM> of.

The stabilizer <NUM> can include or define features to promote or resist certain behavior. For instance, the stabilizer <NUM> can define one or more flex structures <NUM> configured to promote bending of the stabilizer <NUM> in predetermined locations. For instance, the one or more flex structures <NUM> can include one or more holes, grooves, or other areas of relatively less material. The stabilizer <NUM> can define one or more integration structures <NUM> configured to provide positive mechanical integration of the stabilizer <NUM> with the flexible elongate carrier <NUM>. The stabilizer <NUM> can facilitate resisting the stabilizer <NUM> and the carrier <NUM> separating (e.g., peeling apart). The stabilizer <NUM> can define or include one or more protrusions <NUM> to facilitate centering the stabilizer <NUM> within a molding die for the carrier <NUM>. The protrusions <NUM> can be bumps, cylindrical protrusions, rectangular protrusions, or other kinds of protrusions. The protrusions contact the die cavity and keep the main body of the stabilizer <NUM> within the rest of the carrier <NUM>.

The stabilizer <NUM> can take up a percentage of the area of a portion of the carrier <NUM> in cross section perpendicular to the long axis of the carrier <NUM> that is at least x%, where x is an integer in the range between <NUM> and <NUM> in increments of one. In an example, the percentage of the area of a portion of the stabilizer in cross section perpendicular to the long axis of the carrier <NUM> that is at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or at least <NUM>%. The area of the portion of the stabilizer mentioned above regarding the area of the portion of the stabilizer in cross section can be located at a region located at y% of the way along the way along the length of the carrier (measured from the distal end of the carrier), where x is an integer in the range between <NUM> and <NUM> in increments of one. In an example, the area is located at a point <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% of the way along the carrier <NUM>. The stabilizer can reinforce the handle and continuously stiffens the carrier <NUM>. This improves the control offered to the user. The elastic stiffener is less likely to permanently deform. For instance, the device may accidentally deform, bend, or buckle during handling or insertion. Where a metal or glass stiffener may suffer from plastic deformation from such deformation, bending, or buckling, an elastomeric stiffener may elastically deform, which is beneficial.

In some examples, the carrier <NUM> can further include a metallic stiffener. The metallic stiffener can be disposed in one or both of the material of the carrier <NUM> and the material of the stabilizer <NUM>. In some examples, the stabilizer <NUM> is configured to bridge a flexibility gap between the material of the carrier <NUM> and a distal portion of the metallic stiffener. In some examples, the metallic stiffener is configured to provide increased proximal stiffness compared to the use of the stabilizer <NUM> alone. In some examples, the metallic stiffener is disposed in the handle <NUM> and extends distally and stops proximate the collar <NUM>. In other examples (e.g., examples without the collar <NUM>), the metallic stiffener extends distally and stops proximate the most-proximal electrode <NUM>.

<FIG> illustrate various example distances between points of the therapeutic element assembly <NUM>. <FIG> shows distances D1-D3. Distance D1 is the distance from the beginning of a first electrode <NUM> (e.g., the proximal-most electrode <NUM>) to an end of a last electrode <NUM> (e.g., the distal-most electrode <NUM>). Distance D2 is the distance from the distal end of the collar <NUM> to the distal tip of the carrier <NUM>. Distance D3 is the length of the collar <NUM>.

<FIG> shows distances D4-D7. Distance D4 is the distance from the lateral surface <NUM> to the top of the stabilizer <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>, and distance D5 is the distance from the top of the stabilizer <NUM> to a bottom of the carrier <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>, such that the sum of distance D4 and distance D5 is the height of the carrier <NUM> for the illustrated slice. Distance D6 is the distance from the bottom of the carrier <NUM> to the top of the electrode <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>. Distance D7 is width of the carrier <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>.

<FIG> illustrates distances D8-D10. Distance D8 is the distance from the lateral surface <NUM> to the top of the stabilizer <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>. Distance D9 is the distance from the bottom of the carrier <NUM> to the top of the electrode <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>. Distance D10 is a width of the carrier <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>.

E illustrates distances D11-D13. Distance D11 is the height of the carrier <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>. Distance D12 is the distance from the bottom of the carrier <NUM> to the top of the electrode <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>. Distance D13 is the width of the carrier <NUM> for the portion of the therapeutic element assembly <NUM> shown in cross-section in <FIG>.

Table I, below, illustrates example measurements in millimeters for the distances where the therapeutic element assembly <NUM> is used in conjunction with a cochlear implant. In examples, one or more of the distances can vary by ±<NUM> or ±<NUM>. Other measurements can be used.

As can be seen by comparing <FIG>, the size and shape of the stabilizer <NUM> can vary along the length of the stabilizer <NUM>. The stabilizer <NUM> can transition from a first shape to a second shape along at least a portion of the length of the stabilizer <NUM>. In an example, the first shape is the shape of stabilizer <NUM> shown in <FIG> in cross section having a trapezoidal shape with rounded corners, and the second shape is the shape of the stabilizer <NUM> shown in <FIG> in cross section having a substantially circular shape. In another example, the first shape is a non-circular ellipse and the second shape has a circular shape. In an example, the first shape has a width greater than the second shape. In another example, the first shape has a height greater than the second shape.

<FIG> are side views of different example of the stabilizer <NUM>, referred to herein as stabilizers 302A, 302B, and 302C, respectively (generally and collectively referred to as stabilizers <NUM>). The stabilizers <NUM> are configured to be embedded in examples of therapeutic element assemblies <NUM> described above. In these examples, the stiffness or malleability of stabilizer <NUM> is longitudinally varied such that, for example, the distal portion <NUM> of the carrier <NUM> is more flexible than the proximal portion of the carrier <NUM>. Such variability may be attained, for example, by using materials having different characteristics (e.g., as shown in <FIG>), tapering (e.g., as shown in <FIG>), or stepped reduction (e.g., as shown in <FIG>). In these and other examples, there preferably is a gradual transition from the more flexible distal end <NUM> to the stiffer proximal end <NUM> of the carrier <NUM>. It should be appreciated, however, that such a gradual transition in the noted direction may be particular to the example application of cochlear implants and may vary differently in other applications.

Referring to <FIG>, stabilizer 302A is formed from a variety of materials having differing stiffness. In the embodiment shown in <FIG>, longitudinally-adjacent regions <NUM> (only one is identified for simplicity) of the stabilizer 302A are made from different materials having different qualities (e.g., different hardness) or that were subject to different curing processes resulting in regions <NUM> having different hardness or other qualities. In particular, longitudinally successive regions <NUM> have incrementally greater or less flexibility are depicted in <FIG> by successively increasing and decreasing widths of regions <NUM>. In an example, the regions <NUM> can be manufactured via a series of injection molding steps where grades of soft silicone are added and gaps are filled with harder silicone in such a way that there is a smooth variation in total stiffness.

Referring to <FIG>, the stabilizer 302B is, in this illustrated example, a unitary component that is tapered from a proximal end 306B toward a distal end 304B. The reduced volume of material along successive regions of stabilizer <NUM> results in a successively decreasing stiffness. It should be appreciated that the rate of taper will dictate the rate of change in flexibility of the carrier <NUM>.

Referring to <FIG>, the stabilizer 302C is an integrated element having multiple elongate strips 310A-310D of differing lengths. The strips <NUM> can be formed of the same or different material, and may be manufactured to have the same or different stiffness. The strips <NUM> may be secured in any of a variety of manners. As shown in <FIG>, the stabilizer 302C has a stepped configuration, due to the different lengths of strips <NUM>. As such, the stiffness provided by stabilizer 302C varies due to the cumulative contribution of each strip <NUM>, which varies along its length. The strips <NUM> need not be arranged to form a continuous series of steps. For example, the desired flexibility of carrier <NUM> does not vary continuously, strips <NUM> may be configured such that, for example, the strip 310B is longer than the strip <NUM> IOC.

In addition to the embodiments illustrated in <FIG>, the variable stiffness can be achieved by utilizing any number of the following alone or in combination with each other or the embodiments described above: a plurality of stabilizer components spaced at various pitches to provide a variable stiffness; use of different materials at various intervals along the length of the stabilizer <NUM>; varying dimensions of the stabilizer <NUM> or its component elements, etc. It should also be appreciated that the stabilizer <NUM> can be of any manufacturable cross-section, including round, square, rectangular, oval etc., and use any manufacturable method to provide variable stiffness along its length.

In alternative embodiments, the stabilizer <NUM> extends further into the carrier <NUM>, providing regions of enhanced stiffness where desired. It should be appreciated that the regions of stiffness in the embodiments illustrated in <FIG>, or otherwise, need not vary regularly or consistently.

This stiffening arrangement may be similar to that described in <CIT>.

<FIG> illustrates a configuration of the stabilizer <NUM> having a concavity <NUM>. As illustrated, at least one of the wires <NUM> is embedded within the body material of the therapeutic element assembly <NUM> and within the concavity <NUM> along at least a portion of the length of the at least one of the wires <NUM>. Advantageously, this arrangement allows for a compact cross section of the carrier <NUM> while achieving stiffness and stabilization via the stabilizer <NUM>. In examples, the wires <NUM> are arranged into a shape to facilitate fitting within the concavity <NUM>. In the illustrated configuration, the wires <NUM> form a triangular shape configured to fit within the concavity <NUM>. As a particular example, a flexible elongate carrier <NUM> can include a plurality of electrodes <NUM>. Each respective electrode <NUM> can have a wire <NUM> extending therefrom for electrically connecting the respective electrode <NUM> to a device (e.g., an implantable stimulator device separate from the therapeutic element assembly <NUM>). At a point along the flexible elongate carrier <NUM>, the stabilizer <NUM> has a profile defining a concavity <NUM>. At least one of the wires <NUM> is embedded within the first elastomeric body material and within the concavity <NUM>.

<FIG> is a side view of therapeutic element assembly <NUM> shown after insertion into a cochlea. As illustrated, the distance that the stabilizer <NUM> extends into the carrier <NUM> is such that the stabilizer <NUM> terminates just before a lateral wall of the first turn of cochlea <NUM> when the carrier <NUM> is completely inserted into cochlea <NUM>. Advantageously, the stabilizer <NUM> can be configured to provide the carrier <NUM> with sufficient stiffness to allow the carrier <NUM> to be effectively inserted into cochlea <NUM>, particularly once the carrier <NUM> encounters some resistance beyond the first turn of the cochlea <NUM>. A further advantage of the variation in stiffness is to ensure that therapeutic element assembly <NUM> is suitable for various cochlea sizes. Cochlea sizes, and therefore the basal length, from the round window to the lateral wall of cochlea <NUM>, vary slightly between recipients. The basal length is generally a straight path and is usually in the order of approximately <NUM> to <NUM>. The more flexible distal end of the stabilizer <NUM> ensures that the distal tip of the stabilizer <NUM> does not impact with the fragile structures of the cochlea. Rather, the distal end deforms allowing carrier <NUM> to curve whilst still ensuring the proximal region of the therapeutic element assembly <NUM> does not buckle or deform. Preferably, the variable stiffness also ensures that the carrier <NUM> forms a gradual curve rather than a sharp bend that could result by having a sudden change in mechanical stiffness.

<FIG> illustrates an example process <NUM> for manufacturing the carrier <NUM> and associated components. As illustrated, the process <NUM> can begin with operation <NUM> or operation <NUM>.

Operation <NUM> includes forming the stabilizer <NUM> prior to forming the carrier <NUM>. The operation <NUM> can include, for example forming the stabilizer <NUM> using an injection molding process or another suitable manufacturing technique. During this operation <NUM>, the stabilizer <NUM> can be at least partially formed from an elastomeric body material having a hardness greater than a hardness of a material from which the carrier <NUM> will be formed. Further, this operation <NUM> can include forming the stabilizer <NUM> with one or more protrusions <NUM> to facilitate centering the stabilizer <NUM> within a molding die in which the carrier <NUM> is formed. Following operation <NUM>, the flow can move to operation <NUM>.

Operation <NUM> includes forming the carrier <NUM> at least partially from a first elastomeric body material having a first hardness. The carrier <NUM> can be formed using injection molding or another suitable manufacturing technique.

In some examples, operation <NUM> includes operation <NUM>. Operation <NUM> includes encapsulating the stabilizer <NUM> (e.g., as formed in operation <NUM>) in the carrier <NUM>. The carrier <NUM> can be formed from an elastomeric body material (e.g., an elastomeric body material that is less hard than the material from which the stabilizer <NUM> was formed). The elastomeric body material of the carrier <NUM> can be formed around substantially all of the stabilizer <NUM>. This operation <NUM> can include positioning the stabilizer <NUM> within a mold used to form the carrier <NUM>, and forming the carrier <NUM> around at least a portion of the stabilizer <NUM>. Where the stabilizer <NUM> includes the protrusions <NUM>, the protrusions <NUM> can facilitate positioning the stabilizer <NUM> in the mold used to form the carrier <NUM>. The elastomeric body material of the carrier <NUM> can cover all of the stabilizer <NUM> except for the areas of the stabilizer <NUM> having the protrusions <NUM>.

In some examples (e.g., examples in which the stabilizer <NUM> is formed after forming the carrier <NUM>), operation <NUM> includes operation <NUM>. Operation <NUM> includes forming the carrier <NUM> to have a lumen. The lumen can be sized and shaped to facilitate forming the stabilizer <NUM> within the carrier <NUM>. The lumen can be formed by forming the carrier <NUM> around a component having a desired shape for the lumen. Following operation <NUM>, the flow can move to operation <NUM> of operation <NUM>.

Operation <NUM> includes disposing the stabilizer <NUM> in at least a portion of the carrier <NUM>. The stabilizer <NUM> can be at least partially formed from a second elastomeric body material having a second hardness greater than the first hardness. In some examples, this operation <NUM> is achieved by encapsulating the stabilizer in the carrier as described in operation <NUM>.

In some examples, operation <NUM> can include operation <NUM>. Operation <NUM> includes flowing an elastomeric material into the lumen. Following operation <NUM>, the flow can move to operation <NUM>, which includes curing the elastomeric material.

The process <NUM> can include further operations to form components having characteristics described elsewhere herein.

As should be appreciated, while particular uses of the technology have been illustrated and discussed above, the disclosed technology can be used with a variety of devices in accordance with many examples of the technology. The above discussion is not meant to suggest that the disclosed technology is only suitable for implementation within systems akin to that illustrated in the figures. For examples, while certain technologies described herein were primarily described in the context of auditory prostheses (e.g., cochlear implants), technologies disclosed herein are applicable to medical devices generally (e.g., medical devices providing pain management functionality or therapeutic electrical stimulation, such as deep brain stimulation). In general, additional configurations can be used to practice the processes and systems herein and/or some aspects described can be excluded without departing from the processes and systems disclosed herein. Further, the techniques described herein can be applicable to determining a recipient's response to other stimuli, such as visual stimuli, tactile stimuli, olfactory stimuli, taste stimuli, or another stimuli. Likewise, the devices used herein need not be limited to auditory prostheses and can be other medical devices configured to support a human sense, such as bionic eyes.

This disclosure described some aspects of the present technology with reference to the accompanying drawings, in which only some of the possible aspects were shown. Other aspects can, however, be embodied in many different forms and should not be construed as limited to the aspects set forth herein. Rather, these aspects were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible aspects to those skilled in the art.

As should be appreciated, the various aspects (e.g., portions, components, etc.) described with respect to the figures herein are not intended to limit the systems and processes to the particular aspects described. Accordingly, additional configurations can be used to practice the methods and systems herein and/or some aspects described can be excluded without departing from the methods and systems disclosed herein.

Similarly, where steps of a process are disclosed, those steps are described for purposes of illustrating the present methods and systems and are not intended to limit the disclosure to a particular sequence of steps. For example, the steps can be performed in differing order, two or more steps can be performed concurrently, additional steps can be performed, and disclosed steps can be excluded without departing from the present disclosure. Further, the disclosed processes can be repeated.

Claim 1:
An apparatus (<NUM>) comprising a flexible elongate carrier (<NUM>) for introducing a therapeutic element into a recipient, the flexible elongate carrier (<NUM>) comprising:
a first elastomeric body material having a first hardness;
a stabilizer (<NUM>) extending through at least a portion of the first elastomeric body material,
wherein the stabilizer (<NUM>) comprises a second elastomeric body material having a second hardness greater than the first hardness.