Malleable implantable medical device

A malleable implantable medical device for implanting in a recipient comprising a flexible region of the medical device, one or more structures proximate to the flexible region, wherein the one or more structures is configured to provide a bending force to the flexible region, and one or more hermetically sealed medical components coupled to the flexible region, wherein the one or more medical components is configured to provide a therapeutic effect on the recipient.

BACKGROUND

Field of the Invention

The present invention relates generally to implantable medical devices, and more particularly, to malleable implantable medical devices.

Related Art

Implantable medical devices have been used to provide therapeutic benefits to patients for a host of reasons. For example, implantable medical devices may provide therapeutic benefits for those patients who have experienced hearing loss by enhancing or replacing hearing stimulation which they are no longer able to experience. Hearing loss, which may be due to many different causes, is generally of two types, conductive and sensorineural. In some cases, a person may have hearing loss of both types. Conductive hearing loss occurs when the normal mechanical pathways for sound to reach the hair cells in the cochlea are impeded, for example, by damage to the ossicles. Conductive hearing loss is often addressed with conventional hearing aids which amplify sound.

Many people who are profoundly deaf, however, have sensorineural hearing loss. This type of hearing loss is due to the absence or destruction of the hair cells in the cochlea which transduce acoustic signals into nerve impulses. Those suffering from sensorineural hearing loss are thus unable to derive suitable benefit from conventional hearing aids due to the damage to or absence of the mechanism for naturally generating nerve impulses in response to sound.

It is for this purpose that another type of auditory prosthesis, a cochlear implant (also commonly referred to as cochlear prostheses, cochlear devices, cochlear implant devices, and the like; generally and collectively referred to herein as “cochlear implants”) has been developed. Stimulating auditory prostheses such as cochlear implants bypass the hair cells in the cochlea, directly delivering electrical stimulation to the auditory nerve fibers via an implanted electrode assembly. This enables the brain to perceive a hearing sensation resembling the natural hearing sensation normally delivered to the auditory nerve.

Certain implantable medical devices such as cochlear implants are positioned directly underneath the skin and/or placed into an excavated portion of the recipient's bone or tissue. Other implantable medical devices are placed directly on the bone without excavation. A portion of the implanted devices may extend away from the bone or may extend outward from the bone or excavated portion.

SUMMARY

Embodiments of the present invention are generally directed to a malleable implantable medical device which is configurable to conform to the shape of a patient's bone, skull or other natural or artificial structure found at the implantation site. In some embodiments, the malleable implantable medical device comprises one or more therapeutic or medical components, a flexible portion of the device coupled to the therapeutic or medical components, and a structure which is configured to provide a bending force to the flexible portion such that the implantable medical device conforms to a desired shape, such as to the curvature of the recipient's bone or skull. In other embodiments, the malleable implantable medical device may be position in or around the patient's bone, skull or other natural or artificial structures found at the implantation site such that one or more of those structures provide a bending force to the flexible portion of the device in order to have the flexible portion conform to the structure at the implantation site. In yet other embodiments, portions of the malleable implantable medical device are optionally removable in order to have the medical device conform to the shape of a patient's bone, skull or other natural or artificial structures found at the implantation site.

In one embodiment of the present invention, a malleable implantable medical device for implanting in a recipient is provided comprising a flexible region of the medical device, one or more structures proximate to the flexible region, wherein the one or more structures is configured to provide a bending force to the flexible region, and one or more hermetically sealed medical components coupled to the flexible region, wherein the one or more medical components is configured to provide a therapeutic effect on the recipient.

DETAILED DESCRIPTION

Embodiments of the present invention are generally directed to a malleable implantable medical device which can be configured to conform to the shape of a patient's bone, skull or other natural or artificial structures found at the implantation site. In some embodiments, the malleable implantable medical device comprises one or more therapeutic or medical components, a flexible portion of the device which is coupled to the therapeutic or medical components, and a structure which is configured to provide a bending force to the flexible portion such that the implantable medical device conforms to a desired shape, such as to the curvature of the recipient's bone or skull. In other embodiments, the malleable implantable medical device may be position in or around the patient's bone, skull or other natural or artificial structures found at the implantation site such that one or more of those structures provide a bending force to the flexible portion of the device in order to have the flexible portion conform to the structure at the implantation site. In yet other embodiments, portions of the malleable implantable medical device are optionally removable in order to have the medical device conform to the shape of a patient's bone, skull or other natural or artificial structures found at the implantation site.

The malleable implantable medical device of the present invention will be described in conjunction with an implanted unit of a prosthetic hearing implant, such as a cochlear implant sold by Cochlear Limited. It should be understood to those skilled in the art that the present invention may be used in other implanted medical devices, such as neurostimulators, cardiac pacemakers/defibrillators, etc.

FIG. 1is perspective view of one embodiment of a cochlear implant100implanted in a human cochlea140. Referring now toFIG. 1, the relevant components of outer ear101, middle ear105and inner ear107are described next below. In a fully functional ear outer ear101comprises an auricle110and an ear canal102. An acoustic pressure or sound wave103is collected by auricle110and channeled into and through ear canal102. Disposed across the distal end of ear canal102is a tympanic membrane104which vibrates in response to sound wave103. This vibration is coupled to oval window or fenestra ovalis112through three bones of middle ear105, collectively referred to as the ossicles106and comprising the malleus108, the incus109and the stapes111. Bones108,109and111of middle ear105serve to filter and amplify sound wave103, causing oval window112to articulate, or vibrate. Such vibration sets up waves of fluid motion within cochlea140. Such fluid motion, in turn, activates tiny hair cells (not shown) that line the inside of cochlea140. Activation of the hair cells causes appropriate nerve impulses to be transferred through the spiral ganglion cells and auditory nerve114to the brain, where they are perceived as sound.

Cochlear implant100comprises external component assembly142which is directly or indirectly attached to the body of the recipient, and an internal component assembly144which is temporarily or permanently implanted in the recipient. External assembly142typically comprises microphone124for detecting sound, a speech processing unit126, a power source (not shown), and an external transmitter unit128. External transmitter unit128comprises an external coil130and, preferably, a magnet (not shown) secured directly or indirectly to external coil130. Speech processing unit126processes the output of microphone124that is positioned, in the depicted embodiment, by auricle110of the recipient. Speech processing unit126generates coded signals, referred to herein as a stimulation data signals, which are provided to external transmitter unit128via a cable (not shown).

Internal assembly144comprises an internal receiver unit132, a stimulator unit120, and an elongate electrode carrier118. Internal receiver unit132comprises an internal coil136, and preferably, a magnet (also not shown) fixed relative to internal coil136. Internal receiver unit132and stimulator unit120are hermetically sealed within a biocompatible housing. The internal and external coils form a transcutaneous link such that the internal coil receives power and stimulation data from external coil130. Elongate electrode carrier118has a proximal end connected to stimulator unit120and extends from stimulator unit120to cochlea140. Elongate electrode carrier118is implanted into cochlea140via a cochleostomy122.

Elongate electrode carrier118comprises an electrode array146disposed at the distal end thereof. Electrode array146comprises a plurality of longitudinally-aligned electrodes148. Stimulation signals generated by stimulator unit120are applied by electrodes148to cochlea140, thereby stimulating auditory nerve114.

External coil130transmits electrical signals (i.e., power and stimulation data) to the internal coil136via a radio frequency (RF) link. The internal coil136is typically comprised of multiple turns of electrically insulated single-strand or multi-strand platinum or gold wire. The electrical insulation of the internal coil136is provided by a flexible silicone molding (not shown). In use, implantable internal receiver unit132may be positioned in a recess of the temporal bone (not shown) adjacent auricle110of the recipient.

FIG. 2Ais a top view of a cochlear implant100in accordance with one embodiment of the present invention. As discussed previously, cochlear implant100comprises an internal receiver unit132having an internal coil136and is hermetically sealed in biocompatible housing. The portion of the housing for internal receiver unit132having internal coil136may be made of a flexible elastomer (e.g. silicone) such that it will bend when a bending force is applied to the housing. In one embodiment of the present invention, this portion, referred to as flexible region202, contains a sealed chamber204with one or more curable materials206contained within chamber204. The one or more curable materials206contained therein may be cured or otherwise activated, as will be discussed further below. By curing curable materials206inside of a flexible region202of the implantable medical device, flexible region202adopts and retains the shape into which curable materials206are cured. For purposes of this invention, “curable” material should be understood to include materials that can be cured with the application of just energy, such as heat or UV-light, without the addition or other chemicals, compounds or other materials. It should also be understood that “curable” material includes materials which, though not capable of being cured or otherwise activated by itself or even with the addition of various energies such as heat or UV-light, are capable of curing or activating upon the addition of an added chemical, compound or material, either with and without additional energy (e.g., heat, UV-light) being applied to a mixture of the first and second “curable” materials. Curable material206may be a curable silicone elastomer, but may also be any other material suitable for use according to the present invention.

In other embodiments of the present invention, chamber204may be divided into two or more sub-chambers, with different curable materials contained in each sub-chamber. As depicted inFIGS. 2A and 2B, in an exemplary embodiment, first sub-chamber208may contain a first curable material and second sub-chamber210may contain a second curable material, with sub-chambers208,210and internal magnet220configured and positioned such that the integrity of sub-chambers208,210are maintained even with the magnet disposed on or within flexible region202. Sub-chambers208,210may be manufactured initially as a single chamber204with a thin dividing membrane212attached within chamber204, thereby dividing chamber204into sub-chambers208,210, and attached in such a manner that the first and second curable materials placed within sub-chambers208,210do not intermix until they are intentionally combined by an external force. Alternatively, sub-chambers208,210may be manufactured through injection moulding, or some other process now known or later developed, to form the two sub-chambers208,210.

Curable materials206may be cured or otherwise activated so as to change its state from a liquid or gel or paste into a solid upon activation. In one exemplary embodiment wherein flexible region202of the cochlear implant100has a single chamber204containing a single curable material206, an external energy such as heat or light (e.g., UV-light) may be applied in order to cure or activate curable material206contained therein. In another exemplary embodiment depicted inFIGS. 2A-2D, flexible region202of the cochlear implant100has two sub-chambers208and210, each with two different curable materials206which chemically interact with one another, with or without external energy such as heat or UV-light, to change the state of curable materials206into a solid. In other embodiments, the two different curable materials206may not cure or activate even when intermixed without the addition of an external heat or light energy applied to the mixed curable materials206. By applying manual force to flexible region202using one or more fingers or hands, as shown inFIG. 2C, or by using other tools, dividing membrane212is deformed or broken sufficiently to permit intermixing of the different curable materials206with each other. Curable materials206may be further mixed by continued massaging or pushing forces applied manually, to ensure a substantially complete intermixing of curable materials206. Alternatively, once dividing membrane212is sufficiently deformed or broken to allow the intermixing of curable materials206, curable materials206may naturally intermix without external forces being applied to a sufficient level so as to cause the curing or activating of curable materials206.

As shown inFIG. 2D, after curable materials206are intermixed with one another so as to initiate the curing or activating process, the flexible region202is placed against the patient's bone, skull or other structure so that curable materials206cure or activate, resulting in flexible region202conforming to the shape of the object being pressed against. In other embodiments, as shown inFIG. 2D, UV curing light214emits UV light216in the direction of flexible region202to cure curable material206contained therein, where curable material206is a type which will cure only upon the addition of UV light216. When flexible region202is placed against the patient's bone or skull, a bandage or other temporary holding means may be used to hold flexible region202in a fixed location and configuration, allowing curable materials206to cure or activate into a desirable shape. Alternatively, measurements of the structure to which the implantable medical device is to conform to may be taken prior to surgery and used to cure or activate curable materials206prior to surgery, so that the cured flexible region202may more accurately reflect the shape to conform to, or so that the amount of time during which the implantation site is open during surgery can be minimized, among other reasons. These measurements may be taken directly by measuring the shape of the bone or skull when accessible, or may be taken indirectly through data gathered during an x-ray, MRI, CT-scan, or other methods now known or later developed. Further these measurements may be used to create an accurate model of the area the malleable implant is to be placed using a CNC machine to cut the shape from a solid or by using a 3D printer or other method now known or later developed. Upon curing or activating, curable materials206may remain flexible, and may have a softness on the durometer scale (shore A) of approximately 30-60. It is to be understood that the types of curable materials selected for other embodiments of the present invention may depend on the intended uses for the implantable medical device, the techniques or tools used for implanting the medical device, among other factors.

In addition to sub-chambers208,210being positioned in a side-by-side configuration as shown inFIG. 2A, other embodiments of the present invention may be configured to have sub-chambers208,210in a top-bottom configuration wherein the layers are positioned on top of one another, as shown inFIGS. 3A and 3B. This top-bottom configuration may permit a more complete intermixing, or a faster intermixing, of curable materials206A,206B. Additionally, this top-bottom configuration may permit the incorporation of punching tool302into sub-chamber208. Punching tool302has a pushing surface304against which manual pressure, from a finger or another tool, can push to cause sharp tip306of punching tool302to be forced through dividing membrane212, thus permitting the intermixing of curable material206A and206B. Stopper308may limit the depth to which punching tool302may travel so as not to damage the opposing wall of chamber204, were sharp tip306not prevented from traveling too far. The top-bottom configuration depicted inFIGS. 6A and 6Bmay be preferable when incorporating punching tool302since even a slight pressure applied to the broad surface of flexible region202will push the tip of punching tool302through dividing membrane.

As shown inFIGS. 4A and 4B, in other embodiments of the present invention, punching tool302may not have a sharp tip as in the embodiment described above in conjunction withFIG. 3B. In the embodiment shown inFIGS. 4A and 4B, punching tool302has pushing surface304and a broad or flat pushing tip406. Dividing membrane212has perforated region402sized and configured to be pushed apart from membrane212by pushing tip406when a manual force is applied to pushing surface304, which will provide an access for curable materials206A and206B to travel between first chamber208and210in order that curable materials206A and206B can intermix.

FIGS. 5A and 5Bare side and cross-sectional views respectively of a cochlear implant100in accordance with one embodiment of the present invention. In the embodiment shown, first and second sub-chambers208and210are concentric with respect to one another, within dividing membrane212positioned between sub-chambers208,210. Upon manual pressure being applied to dividing membrane212, curable materials206A,206B are permitted to intermix, in the manner described above.

Although previously described embodiments have referenced figures in which first and second sub-chambers208,210appear to be equal in size, thus containing approximately equal volumes of curable materials206A,206B, it is to be understood that sub-chambers208,210may be of different sizes, as shown inFIG. 6. Furthermore, it is to be understood that sub-chambers208,210may be completely filled with curable material206or may only be partially filled with curable material206under the present invention. InFIG. 6, flexible region202contains chamber204having first sub-chamber208and second sub-chamber210which is defined by the presence of dividing membrane212in chamber204so as to define sub-chambers208,210. The embodiment ofFIG. 6may be useful where the volumes of curable material206A and206B are necessarily unequal with respect to one another to achieve a desired curing aspect such as speed or type of curing.

It is further to be understood that, although multi-chamber configurations described previously have referred only to a first and second sub-chamber, more than two sub-chambers may be present in chamber204according to the present invention. InFIG. 7, in an exemplary embodiment, sub-chambers708,710,712,714contain curable materials706A,706B,706C,706D respectively, wherein dividing membrane716separates sub-chambers708,710and wherein dividing membrane718separates sub-chambers712,714. By having two sets of sub-chambers (708/710and712/714) in the embodiment ofFIG. 7, a first set may be manipulated and cured prior to manipulating and curing the second set, where doing so may be desirable for accuracy or other reasons. Additionally, curable materials706A,706B intermixed in the first set of sub-chambers708,710may be selected to provide a different result, such as a different softness or level of flexibility, than curable materials706C,706D intermixed in the second set of sub-chambers712,714.

FIGS. 8A and 8Bare perspective views of a cochlear implant100in accordance with another embodiment of the present invention. In addition to, or instead of, providing a curable material206in chamber204, curable material206may be provided to the space defined by chamber204through the use of a syringe802. Syringe802may be filled with curable material206and inserted into a surface of flexible region202, then plunged so as to fill chamber204with curable material206. Curable material206may be a single material which can be cured or activated without the addition of a catalyst or other material, through one or more energies (e.g., heat) or light (e.g., UV-light) being applied to curable material206. In alternative embodiments, chamber204may be filled with a first curable material206A of a multi-part curable material arrangement in which a second and necessary curable material206B, such as a catalyst, may be provided to chamber204through syringe802. In yet another embodiment of the present invention, chamber204may be substantially empty, whereby curable materials206A and206B in a self-curing or self-activating are intermixed and immediately provided to chamber204through syringe802before curable materials206A and206B cure or activate in a solid which provides a bending stress to flexible region202, as described previously.

In yet another embodiment of the present invention in which a bending force is provided to a flexible region202of an implantable medical device,FIGS. 9A-9Cshows an embodiment in which a bendable structure902is provided against a surface of flexible region202and bent by a desired amount, resulting in the bending of flexible region202. As shown inFIG. 9A, a bendable structure902is adhered to a surface of flexible region202. As shown inFIG. 9B, in other embodiments, bendable structure902is embedded within silicone flexible region202. As shown inFIG. 9C, when bendable structure902is bent, it retains the angle into which it was bent, and causes flexible region202to adopt a similar angle. Bendable structure902may be a metal or alloy such as titanium in some embodiments, and may be configured in the shape of a spine, but may also be a non-metallic structure such as a series of interlocking plastic structures configured to be bent and to retain the bend with sufficient force to counteract any straightening force which may be exerted by flexible region202. In addition to bendable structure902being positioned on the surface of internal receiver unit132facing the recipient's bone or skull in certain embodiments, bendable structure902may be positioned along the outer or other surface of internal receiver unit in other embodiments of the present invention, depending on the intended use and other considerations. Multiple bendable structures similar to902may be used to create different levels of curvature in different locations which may allow still closer fit to the shape of the bone or skull or other feature.

FIGS. 10A, 10B, 10C, 10D, 10Eare cross-sectional views of a flexible wing proximate to a stimulator unit of a cochlear implant100in accordance with an embodiment of the present invention. Internal receiver unit132of a cochlear implant100has wing1004constructed in various exemplary embodiments of the present invention. Internal receiver unit132may be implanted into a recipient by attaching internal receiver unit132to a bone or tissue or inserting internal receiver unit132into an excavated bone. Wing1004is flexible and may extend around the entire perimeter or circumference of internal receiver unit132or a portion thereof.FIG. 10Ashows wing1004attached near an upper surface1006of internal receiver unit132. Wing1004may extend beyond internal receiver unit132so that when inserted, wing1004may begin to flex outward before internal receiver unit132rests on the bone or tissue.

FIG. 10Bshows wing1004attached along a side surface1008of internal receiver unit132. Wing1004has a rim1010that contacts the bone or tissue and also has an indentation1012along a lower surface1014of wing1004.

FIG. 10Cshows wing1004having a hinge1016near upper surface1006of internal receiver unit132. Hinge1016allows wing1004to pivot in addition to flexing. Wing1004may be adhered to hinge1016, and hinge1016may be integral or adhered to internal receiver unit132. Wing1004is shown with a constant slope, but may have a slope substantially similar toFIG. 10A or 10B.

FIG. 10Dshows wing1004having a solid skirt1018that extends along side surface1008of internal receiver unit132. Solid skirt1018may have a rim1010as shown inFIG. 10B. Solid skirt1018may be made of a flexible material that bends and compresses.

FIG. 10Eshows wing1004that extends along side surface1008of internal receiver unit132and has a series of removable segments1020. Each removable segment1020may be detached to accommodate the depth of the bone excavation or the position/arrangement of the bone or tissue. The portion of wing1004that remains intact may be flexible or may have a solid skirt1018as shown inFIG. 10D.

The wing cross-sections shown inFIGS. 10A, 10B, 10C, 10D, and 10Emay also be integral with the hermetically sealed biocompatible housing surrounding internal receiver unit132of the medical device. In addition, the wing may be part of a slipcover that extends over the housing of the medical device and is held on by an adhesive and/or the friction of the slipcover.

When a medical device is inserted into a bone excavation the wing will flex outwards to form a smooth transition from the medical device to the bone. In addition, when a medical device rests on a bone or other tissue, the wing may also flex outwards to form a smooth transition. The flexing of the wing may be uniform around the perimeter or circumference of the housing or the wing may flex more along some portions and less along other portions depending on the nature of the medical device and/or the nature of the bone or tissue surrounding the medical device. Embodiments of the present invention may allow the wing to move away from the medical device when the medical device is positioned into the bone excavation. The free end of the wing, i.e., the end not adhered to the medical device, remains in contact with the bone or tissue and may adapt to the curvature of each recipient's bone/tissue structure. In some embodiments the free end of the wing does not contact the bone or tissue, but extends substantially towards the bone or tissue and may have a tapering portion or contour that adapts to the curvature of each recipient's bone/tissue structure.

An advantage of such a wing of the present invention may be to provide comfort to recipients regardless of where the medical device is implanted or how the medical device is implanted. The recipient using embodiments of the present invention may not notice or feel the protrusion caused by the medical device since the smooth transition makes the medical device less obvious to the touch. In addition, another advantage of the present invention is that the medical device may be placed in an excavation at any depth since the wing will flex outward. Another advantage of the present invention is that the smooth transition may reduce the chances of skin erosion around the medical implant device. Another advantage is that the smooth transition may reduce areas where body fluids may stagnate which could increase the likelihood of infection and/or biofilms forming on the device.

FIGS. 11A and 11Bare perspective top and end views respectively of a flexible wing proximate to an internal coil of a cochlear implant100in accordance with an embodiment of the present invention. Prosthetic hearing implant internal receiver unit132is depicted with internal coil136and stimulator unit120. Stimulator unit120is connected to an electrode array146(not shown) through tab1108. Wing1110may be provided on a portion of the perimeter or circumference of coil136. Wing1110has a rim1112, but may be constructed to have any other cross-sectional shape as described above. Wing1110may have several cuts1114where none of the sloping portion of wing1110is present. Rim1112extends along the length of cuts1114to form a continuous piece.

In an embodiment of the present invention, the wing may be provided without a rim, but still has several cuts in the wing. The cuts create several flaps of the wing that may flex independent of the other flaps. Alternatively, a rim may be positioned between two or more flaps to provide a uniform flexing amongst the flaps that are connected.

In an embodiment of the present invention, the wing may be provided without any cuts and may have a solid skirt shape as shown in and described in conjunction withFIG. 10D.

FIG. 12shows a top perspective view of a prosthetic hearing implant internal receiver unit132having internal coil136and stimulator unit120. Stimulator unit120is connected to an electrode array146(not shown) through tab1108. Wing1210may be adhered to or placed on a portion of the perimeter or circumference of stimulator unit120. Wing1210has a rim1212, but may be constructed to have any other cross-sectional shape as described above. Wing1210may have several cuts1214where none of the sloping portion of wing1210is present. Rim1212and wing1210may extend around tab1108.

FIGS. 13A and 13Bshow bottom perspective views of a prosthetic hearing implant internal receiver unit132having internal coil136and stimulator unit120. Stimulator unit120is connected to an electrode array146through tab1108. Wing1310may be adhered to or placed on the perimeter or circumference of implant internal receiver unit132. Wing1310has a rim1312, but may be constructed to have any other cross-sectional shape as described above. Wing1310may have several cuts1314where none of the sloping portion of wing1310is present. Rim1312and wing1310may extend around tab1108.

Cuts1114,1214,1314in a wing1110,1210,1310of the present invention may provide fixation of internal receiver unit132by allowing tissue or bone to grow in the vacant area, such as what occurs in osseointegration. In addition, cuts1114,1214,1314may allow fluid circulation around internal receiver unit132to prevent bacterial growth.

Different wing shapes, such as shown inFIGS. 10A, 10B, 10C, 10D, and 10E, may be used on or in conjunction with internal receiver unit132. In addition, one wing shape may be used on a portion of the housing for internal coil136, while a second wing shape is used on the other portion of the housing. Alternatively, two or more wings may be used that have different wing shapes.

FIG. 14Ais a perspective view of a removable pedestal1402proximate to a stimulator unit120of a cochlear implant100in accordance with an embodiment of the present invention. Other components of cochlear implant100such as internal coil136are not depicted inFIGS. 14A, 14B and 14Cfor purposes of simplicity and clarity. As depicted inFIG. 14A, removable pedestal1402is attached to a bottom surface of stimulator unit120. A bottom surface is to be understood as the surface that of stimulator unit120which is facing approximately in the direction of the patient's bone or skull. Removable pedestal1402may be constructed of any suitable material, including the same flexible silicone material which may be used in one embodiment to form the biocompatible housing around stimulator unit120and internal coil136.

Removable pedestal1402and receiver unit132may be manufactured and provided to the surgeon already joined to one another. A wire cutter1404is sandwiched between removable pedestal1402and a surface of internal receiver unit132. Wire cutter1404is of sufficient length and positioned such that two ends of wire cutter1404extend beyond removable pedestal1402enough so that a tool or fingers may be used to grip and utilize the ends of wire cutter1404to either remove it from internal receiver unit132or as a cutting tool for cutting removable pedestal1402, as will be described further below in conjunction withFIGS. 14B and 14C. Alternatively, removable pedestal1402may be manufactured separately from internal receiver unit132and provided for surgery as separate parts. When manufactured and provided as separate parts, these separate parts may be assembled and joined together a relatively short time before surgery by methods already known or later developed, such as by glue, screw, corresponding tabs or clips.

FIG. 14Bis a perspective view of removable pedestal1402proximate to internal receiver unit132of a cochlear implant100in accordance with an embodiment of the present invention in which removable pedestal1402will remain affixed to internal receiver unit132after implantation. When removable pedestal1402and internal receiver unit132are provided to the surgeon as assembled or joined parts from the manufacturer, the surgeon has the option of altering internal receiver unit132. The surgeon may do this to make it conform to the shape of the recipient's bone or skull depending on the condition and preparation of the implant site or through a preference for a surgical technique which avoids bone drilling. Where a suitably dimensioned bone bed has been formed in the bone through excavation, internal receiver unit132may be positioned in the implantation site with removable pedestal1402intact. Implanting internal receiver unit132with removable pedestal1402intact may be useful for maintaining the location of internal receiver unit132, as any translational force on internal receiver unit132will be counteracted by the pedestal1402pushing against the adjacent surface of the bone bed. Furthermore, removable pedestal1402may be useful in maintaining the position of receiver unit132within a bone bed such that a desired distance between the bottom surface of receiver unit132and the surface of the excavated bone bed may be maintained. In this scenario, it may be desirable to remove wire cutter1404to minimize unnecessary objects being placed in the implantation site and to make removable pedestal1402a permanent part of the implanted receiver unit132. To remove wire cutter1404, a single end of wire cutter1404may be pulled which will remove wire cutter1404from the internal receiver unit132without cutting or otherwise detaching removal pedestal1402from internal receiver unit132.

FIG. 14Cis a perspective view of removable pedestal1402proximate to internal receiver unit132of a cochlear implant100in accordance with an embodiment of the present invention in which removable pedestal1402will be removed from internal receiver unit132prior to implantation. As discussed previously, when removable pedestal1402and internal receiver unit132are provided to the surgeon as assembled or joined parts from the manufacturer, the surgeon may opt to remove removable pedestal1402from internal receiver unit132in order to have internal receiver unit132conform to the shape of the recipient's bone or skull. For example, where the surgeon is not excavating a bone bed into which implantable components will be positioned, it may be desirable to modify internal receiver unit132to remove removable pedestal1402in order to minimize the thickness of internal receiver unit132or otherwise to have internal receiver unit132better conform to the shape of the recipient's bone or skull at the implantation site. To remove removable pedestal1402from internal receiver unit132, both ends of wire cutter1404may be pulled simultaneously in order to cut or otherwise detach removable pedestal1402. Other mechanisms for making removable pedestal1402easily removable from internal receiver unit132are also considered a part of this invention and may be provided or used together with, or instead of, wire cutter1404. For example, a scalpel may be used to cut removable pedestal1402partially or completely from internal receiver unit132. In another exemplary embodiment, removable pedestal1402may have a drastically reduced cross-section at a point on removable pedestal1402near internal receiver unit132. The reduced cross-section may provide a weak point which can be torn by sufficient manual pulling force applied to the removable pedestal1402or to internal receiver unit132. In a yet further exemplary embodiment, removable pedestal1402may have perforations along its border near internal receiver unit132which are configured to tear when sufficient manual pulling force is applied to removable pedestal1402or to internal receiver unit132.

Although the present invention has been fully described in conjunction with several embodiments thereof with reference to the accompanying drawings, it is to be understood that various changes and modifications may be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.