Patent Application
20110152991
1. Field of the Invention
The present invention relates generally to implantable medical devices including an implantable electrode assembly, and more particularly, to strain relief in an implantable electrode assembly.
2. Related Art
Hearing loss, which may be due to many different causes, is generally of two types, conductive and sensorineural. In some cases, a person suffers from hearing loss of both types. Conductive hearing loss occurs when the normal mechanical pathways for sound to reach the cochlea, and thus the sensory hair cells therein, are impeded, for example, by damage to the ossicles. Individuals who suffer from conductive hearing loss typically have some form of residual hearing because the hair cells in the cochlea are undamaged. As a result, individuals suffering from conductive hearing loss typically receive an acoustic hearing aid that generates mechanical motion of the cochlea fluid.
In many people who are profoundly deaf, however, the reason for their deafness is sensorineural hearing loss. Sensorineural hearing loss occurs when there is damage to the inner ear, or to the nerve pathways from the inner ear to the brain. As such, those suffering from some forms of sensorineural hearing loss are thus unable to derive suitable benefit from hearing prostheses that generate mechanical motion of the cochlea fluid. As a result, medical devices having one or more implantable components that deliver electrical stimulation signals to a patient or recipient (“recipient” herein) have been developed. Certain such implantable medical devices include an array of stimulating electrode contacts that deliver the stimulation signals to nerve cells of the recipient's auditory system, thereby providing the recipient with a hearing percept.
As used herein, the recipient's auditory system includes all sensory system components used to perceive a sound signal, such as hearing sensation receptors, neural pathways, including the auditory nerve and spiral ganglion, and parts of the brain used to sense sounds. Electrically-stimulating implantable medical devices include, for example, auditory brain stimulators and cochlear prostheses (commonly referred to as cochlear prosthetic devices, cochlear implants, cochlear devices, and the like; simply “cochlear implants” herein.)
Oftentimes sensorineural hearing loss is due to the absence or destruction of the cochlear hair cells which transduce acoustic signals into nerve impulses. It is for this purpose that cochlear implants have been developed. Cochlear implants provide a recipient with a hearing percept by delivering electrical stimulation signals directly to the auditory nerve cells, thereby bypassing absent or defective hair cells that normally transduce acoustic vibrations into neural activity. Such devices generally use an electrode array implanted in the cochlea so that the electrodes may differentially activate auditory neurons that normally encode differential pitches of sound.
Auditory brain stimulators are used to treat a smaller number of recipients with bilateral degeneration of the auditory nerve. For such recipients, the auditory brain stimulator provides stimulation of the cochlear nucleus in the brainstem.
In accordance with one aspect of the present invention, an implantable electrode assembly is provided. The electrode assembly comprises: an elongate carrier member; at least one electrode contact disposed in the carrier member; and at least one elongate conductive pathway disposed in the carrier member having a distal end attached to the at least one electrode contact and having a substantially planar strain relief formed therein that is located only in the distal region of the pathway.
In accordance with another aspect of the present invention, an implantable electrode assembly is provided. The electrode assembly comprises: an elongate carrier member; at least one electrode contact disposed in the carrier member; at least one elongate conductive pathway disposed in the carrier member having a distal end attached to the at least one electrode contact via a contact joint and having a strain relief formed therein; and an anchor arrangement securing the pathway to the electrode contact adjacent to the contact joint.
In accordance with a still other aspect of the present invention, an implantable electrode assembly is provided. The electrode assembly comprises: an elongate carrier member; at least one electrode contact disposed in the carrier member; at least one elongate conductive pathway disposed in the carrier member having a distal end attached to the at least one electrode contact; and an anchor arrangement securing the pathway to the electrode contact adjacent to the contact joint.
Aspects and embodiments of the present invention are described herein with reference to the accompanying drawings, in which:
Aspects of the present invention are generally directed to strain relief features in an implantable electrode assembly. More specifically, the electrode assembly includes at least one electrode contact and an elongate conductive pathway disposed in an elongate carrier member. and A distal end of the conductive pathway is attached to the at least one electrode contact via a contact joint, and has a strain relief formed therein. The strain relief decreases the susceptibility of the elongate conductive pathway and/or contact joint to breakage resulting from flexing/bending of the electrode assembly.
As described below, a strain relief in accordance with embodiments of the present invention may have a variety of arrangements. In certain embodiments, the strain relief is substantially planar and may be located, for example, only in a distal region of the conductive pathway. In other embodiments, the conductive pathway is secured to the electrode contact at a location adjacent to the contact joint to further protect the contact joint from breakage.
Embodiments are described herein primarily in connection with one type of implantable medical device, a hearing prosthesis, and more specifically a cochlear implant. Cochlear implants are hearing prostheses that deliver electrical stimulation, alone or in combination with other types of stimulation, to the cochlear of a recipient. Therefore, as used herein a cochlear implant refers to a device that delivers electrical stimulation in combination with other types of stimulation, such as acoustic and/or mechanical stimulation.
It would be appreciated that embodiments of the present invention may be implemented in any cochlear implant or other hearing prosthesis now know or later developed; including auditory brain stimulators (also known as auditory brainstem implants (ABIs)). Furthermore, it would be understood that embodiments of the present invention may be implemented in implantable medical devices other than cochlear implants such as neurostimulators, cardiac pacemakers/defibrillators, functional electrical stimulators (FES), spinal cord stimulators (SCS), etc.
In a fully functional ear, outer ear 101 comprises an auricle 110 and an ear canal 102. An acoustic pressure or sound wave 103 is collected by auricle 110 and channeled into and through ear canal 102. Disposed across the distal end of ear cannel 102 is a tympanic membrane 104 which vibrates in response to sound wave 103. This vibration is coupled to oval window or fenestra ovalis 112 through three bones of middle ear 105, collectively referred to as the ossicles 106 and comprising the malleus 108, the incus 109 and the stapes 111. Bones 108, 109 and 111 of middle ear 105 serve to filter and amplify sound wave 103, causing oval window 112 to articulate, or vibrate in response to vibration of tympanic membrane 104. This vibration sets up waves of fluid motion of the perilymph within cochlea 140. Such fluid motion, in turn, activates tiny hair cells (not shown) inside of cochlea 140. Activation of the hair cells causes appropriate nerve impulses to be generated and transferred through the spiral ganglion cells (not shown) and auditory nerve 114 to the brain (also not shown) where they are perceived as sound.
Cochlear implant 100 comprises an external component 142 which is directly or indirectly attached to the body of the recipient, and an internal or implantable component 144 which is temporarily or permanently implanted in the recipient. External component 142 typically comprises one or more sound input elements, such as microphone 124 for detecting sound, a sound processing unit 126, a power source (not shown), and an external transmitter unit 128. External transmitter unit 128 comprises an external coil 130 and, preferably, a magnet (not shown) secured directly or indirectly to external coil 130. Sound processing unit 126 processes the output of microphone 124 that is positioned, in the depicted embodiment, by auricle 110 of the recipient. Sound processing unit 126 generates encoded signals, sometimes referred to herein as encoded data signals, which are provided to external transmitter unit 128 via a cable (not shown).
Internal component 144 comprises an internal receiver unit 132, a stimulator unit 120, and an elongate stimulating lead assembly 118. Internal receiver unit 132 comprises an internal coil 136, and preferably, a magnet (also not shown) fixed relative to the internal coil. Internal receiver unit 132 and stimulator unit 120 are hermetically sealed within a biocompatible housing, sometimes collectively referred to as a stimulator/receiver unit. Internal coil 136 receives power and stimulation data from external coil 130, as noted above. Elongate stimulating lead assembly 118 has a proximal end connected to stimulator unit 120, and extends through mastoid bone 119. Lead assembly 118 has a distal region, referred to as electrode assembly 145, implanted in cochlea 140. As used herein the term “stimulating lead assembly,” refers to any device capable of providing stimulation to a recipient, such as, for example, electrical or optical stimulation.
Electrode assembly 145 may be implanted at least in basal region 116 of cochlea 140, and sometimes further. For example, electrode assembly 145 may extend towards apical end of cochlea 140, referred to as cochlea apex 134. Electrode assembly 145 may be inserted into cochlea 140 via a cochleostomy 122, or through round window 121, oval window 112, and the promontory 123 or opening in an apical turn 147 of cochlea 140.
Electrode assembly 145 has disposed therein or thereon a longitudinally aligned and distally extending array 146 of electrode contacts 148, sometimes referred to as electrode array 146 herein. Throughout this description, the term “electrode array” means a collection of two or more electrode contacts, sometimes referred to simply as contacts herein. As would be appreciated, electrode array 146 may be disposed on electrode assembly 145. However, in most practical applications, electrode array 146 is integrated into electrode assembly 145. As used herein, electrode contacts or other elements disposed in a carrier refer to elements integrated in, or positioned on, the carrier member. As such, electrode array 146 is referred to herein as being disposed in electrode assembly 145. Stimulator unit 120 generates stimulation signals which are applied by electrodes 148 to cochlea 140, thereby stimulating auditory nerve 114.
In cochlear implant 100, external coil 130 transmits electrical signals (i.e., power and stimulation data) to internal coil 136 via a radio frequency (RF) link. Internal coil 136 is typically a wire antenna coil comprised of multiple turns of electrically insulated single-strand or multi-strand platinum or gold wire. The electrical insulation of internal coil 136 is provided by a flexible silicone molding (not shown). In use, implantable receiver unit 132 may be positioned in a recess of the temporal bone adjacent auricle 110 of the recipient.
As noted,
In certain embodiments, electrode assembly 218 is configured to adopt a curved configuration during or after implantation into the recipient's cochlea. To achieve this, in certain embodiments, electrode assembly 218 is pre-curved to the same general curvature of a cochlea. In such embodiments, electrode assembly 218 is referred to as perimodiolar electrode assembly that is held straight by, for example, a stiffening stylet (not shown) which is removed during implantation so that the electrode assembly may adopt its curved configuration when in the cochlea. Other methods of implantation, as well as other electrode assemblies which adopt a curved configuration, may be used in embodiments of the present invention.
In other embodiments, electrode assembly 218 is a non-perimodiolar electrode assembly which does not adopt a curved configuration. For example, electrode assembly 218 may comprise a straight electrode assembly or a mid-scala assembly which assumes a mid-scala position during or following implantation.
In the illustrative embodiments of
As noted above, aspects of the present invention are generally directed to strain relief features in an implantable electrode assembly.
As shown in
As noted above, electrical stimulation signals are generated by stimulator unit 202 and provided to electrode contacts 248 via wires 342. Electrode contacts 248 deliver the electrical stimulation signals to the recipient. Thus, to ensure proper operation of the cochlear implant, it is important to maintain the electrical connection between stimulator unit 202 and electrode contacts 248. Embodiments of the present invention are configured to maintain the electrical connection by providing a strain relief feature, or simply strain relief herein, in wires 342. As used herein, a strain relief refers to a non-linear section of the wire that is embedded in a flexible material, such as silicone.
During use, the flexible material holds the strain relief in shape, but allows movement of the stored length of with when loads are placed on wires 342 as a result of bending and straightening of electrode assembly 218. The strain reliefs prevent breakage of the electrical connection between stimulator unit 202 and electrode contacts 248 in response to such flexing/bending of electrode assembly 218A.
In the illustrative embodiments of
Localization of strain reliefs 330, 332 to the electrode contact region helps to protect the portions of the electrical connection between stimulator/receiver unit 202 and electrode contacts 248 that are most susceptible to breakage. The region of the electrical connection between stimulator/receiver unit 202 and electrode contacts 248 disposed in the electrode contact region is susceptible to breakage for several reasons. As discussed below, several methods, including resistance welding, wire bonding, and crimping may be used to join conductive pathways 342 to electrode contacts 248. Alternatively, conductive pathways 342 and electrode contacts may be cut, stamped or fabricated (i.e. thin film fabrication) from a single piece of material. All of the formed connections are themselves susceptible to breakage, but the above methods also potentially damage the conductive pathway making the pathway more prone to breakage. For instance, resistance welding or wire bonding may result in a heat affected zone (HAZ) and deformation to the wire, while crimping may result in stress imparted weakness (e.g. from deformation of the material). Also, cutting or stamping may result in a geometric weakness in the connecting region, while thin film fabrication is prone to surface tension effects. Therefore, for these and other regions, the electrode contact region is particularly prone to damage during use.
In the embodiments of
In the embodiments of
Thus, the illustrative embodiments of
A second advantage of strain reliefs 330, 332 positioned proximate to electrode contacts 248, is that the strain reliefs do not overlap with one another. The non-overlapping strain reliefs created a compact wire bundle, and thus saves space within electrode assembly 218. Furthermore, because the strain reliefs to not overlap, the proximal portions of the wires are in a close bundle. The close bundle helps to protect the wires from breakage.
In alternative embodiments of the present, the strain reliefs are positioned proximate to electrode contacts 248, but extend beyond the next most proximal electrode contact. In certain such embodiments, the strain reliefs extend the length of intra-cochlea region 212.
As detailed above,
Strain relief 430 illustrated in
As shown in
As noted above, a variety of methods may be implemented to attach or join a conductive pathway, such as a wire, to an electrode contact. The attachment or connection point between a wire or other conductive pathway and an electrode contact is referred to herein as contact joint 444. Contact joint 444 may be provided by resistance welding, wire bonding, crimping, laser welding, etc. In certain circumstances, the wire and electrode contact are cut out or stamped from a single sheet of metal, and the contact joint is the region where the element changes from the electrode shape to the wire shape.
As noted above, a strain relief, such as strain relief 430, comprises a non-linear section of wire 442 that is surrounded by a flexible material such as silicone. In order to provide movement of the strain relief 430 in response to, for example, flexing/bending of the electrode assembly, strain relief 430 must be spaced a distance from electrode contact 248 so that the strain relief is not fixed to a rigid structure, such as the electrode contact. This distance may comprise, for example, 50 to 100 microns.
The desired distance between electrode contact 248 and strain relief 430 may be provided in several different manners. For instance, as shown in
In the embodiments of
As shown, the distal end of wire 542A is attached to electrode contact 548A via a contact joint 544A. In the embodiments of
Furthermore, in the embodiments of
In alternative embodiments, helical strain relief 532 has a length that is greater than electrode contact 548B. For exampled, helical strain relief 532 may extend to the next most proximal electrode and is positioned within electrode contact 548A and the adjacent electrode gap, as described above with reference to
As shown, the distal end of wire 542B is attached to electrode contact 548B via a contact joint 544B. In the embodiments of
Furthermore, in the embodiments of
As shown, the distal end of wire 542D is attached to electrode contact 548D via a contact joint 544D. In the embodiments of
As is well known in the art, an electrode assembly configured for implantation in a cochlea has a diameter that decreases towards the distal end of the electrode assembly. That is, the width of electrode assembly tapers to a distal tip. In certain embodiments of the present invention, strain reliefs are formed to take advantage of the changing diameter of an electrode assembly. Specifically, wires within the electrode assembly have different shaped and/or sized strain reliefs based on the size of the electrode assembly in the region of the strain relief. In other words, the wires include different strain reliefs designed to maximize the use of the electrode assembly.
As shown, a first strain relief 630A is formed in a wire 642A. The distal end of wire 642A is attached to electrode contact 648A. Strain relief 630A has a width 660 which is configured to maximize the space available in the region of electrode assembly 618 in which electrode contact 648A is positioned. As noted above, the length of a strain relief refers to the distance from the most proximal end of the relief to the most distal end of the relief. As used herein, the width of a strain relief refers to the largest dimensions of the strain relief in the direction perpendicular to the length of the strain relief.
Electrode assembly 618 further includes a second strain relief 630C formed in a wire 642C. The distal end of wire 642C is attached to electrode contact 648C. Strain relief 630C has a width 662. The width 662 of strain relief 630C is smaller than the width of strain relief 630A, shown by arrows 664. Again, the width 662 of strain relief 630C is selected to maximize the space available in the region of electrode assembly 618 in which electrode contact 648C is positioned. As would be appreciated, the difference in width between strain reliefs 630A, 630C is due to the taper of electrode assembly 618.
Electrode assembly 618 further includes a third strain relief 630B which is optimized for the space available at electrode contact 648B. For ease of illustration, the decrease in size between strain reliefs 630A and 630B are not shown herein.
The embodiments of
Furthermore, the embodiments of
As noted above, embodiments of the present invention are directed to maintaining the electrical connection between stimulator/receiver unit 202 (
As detailed above, strain reliefs 730 are configured to reduce the susceptibility of the electrical connection between the stimulator unit and electrode contact 748 to breakage as a result of, for example, flexing/bending of an electrode assembly in which the electrode contact and wires 742 are positioned. The use of two wires 742 extending between electrode contact 748 and the stimulator unit further reduces the susceptibility of the electrical connection to breakage by providing a redundant path between the stimulator unit and the electrode contact. If one of wires 742 is broken, the electrical connection is maintained by the second wire.
As noted above, a variety of methods may be implemented to attach or join a conductive pathway, such as a wire, to an electrode contact. The attachment or connection point between a wire or other conductive pathway and an electrode contact is referred to herein as a contact joint. A contact joint may be provided by welding, wire bonding, crimping, laser welding, etc. In certain circumstances, the wire and electrode contact are cut out or stamped from a single sheet of metal, and the contact joint is the region where the element changes from the electrode shape to the wire shape.
As noted above, a conductive pathway is attached to an electrode contact via a contact joint. Methods for forming this contact joint including resistance welding, wire bonding, and crimping. Alternatively, conductive pathways and electrode contacts may be cut, stamped or fabricated (i.e. thin film fabrication) from a single piece of material. All of the formed connections are themselves susceptible to breakage, but the above methods also potentially damage the conductive pathway making the pathway more prone to breakage. For instance, resistance welding or wire bonding may result in a heat affected zone (HAZ) and deformation to the wire, while crimping may result in stress imparted weakness (e.g. from deformation of the material). Also, cutting or stamping may result in a geometric weakness in the connecting region, while thin film fabrication is prone to surface tension effects. Therefore, for these and other regions, the electrode contact region is particularly prone to damage during use.
Also as noted, as a result of, for example, flexing/bending of an electrode assembly, a wire connecting an electrode contact to a stimulator unit is exposed to forces that may damage the electrical connection between the stimulator unit and the electrode contact. Thus, a strain relief is provided to reduce the likely that the wire will break as a result of such flexing/bending. Embodiments of the present invention provide additional features which further serve to maintain the integrity of the electrical connection by protecting the contact joint from external forces. In particular, embodiments of the present invention are configured to protect the contact joint from flexing/bending forces by securing the conductive pathway to the electrode contact adjacent to the contact joint with an anchor arrangement. As used herein, an anchor arrangement refers to a collection one or more elements positioned substantially between the strain relief and the contact joint that are used to secure the section of wire to the electrode contact.
In the embodiments of
Due to the close proximity of wire 842 and contact 848 (distance 812) adjacent to contact joint 844, silicone 814 substantially prevents movement of the portion of wire 848 that is adjacent to contact joint 844, and thus helps to prevent damage to the contact joint as a result of bending of the electrode assembly.
In contrast, as the distance between wire 842 and electrode contact 848 increases, more silicone 814 is positioned there between. This increasing larger amount of silicone between wire 842 and electrode contact 848 provides for increasing greater freedom of movement of wire 842. Thus, in the embodiments of
The embodiments of
In certain embodiments of the present invention, the same flexible material, such as silicone, may be used to form the anchor arrangement and to surround the strain relief. However, it would be appreciated that materials such as epoxy cannot be used to surround the strain relief because such materials do not permit sufficient movement of the strain relief upon bending/flexing of the electrode assembly.
In the illustrative embodiments of
As would be appreciated, relatively strong welds, such as a fusion welds, are used to attach the distal end of a conductive pathway to an electrode contact. In embodiments in which a weld is used as an anchor arrangement, the anchoring weld is configured to break prior to breakage of the wire. Furthermore, it is desirable to damage the wire as little as possible during the anchoring processed. Therefore, an anchoring weld comprises a tack weld rather than a fusion weld. A tack weld is weaker than a fusion weld, and the tack welding process helps to reduce heat affected zones in the wire caused by the welding process.
In the embodiments of
As noted above, an electrode assembly in accordance with embodiments of the present invention includes several elements, such as a carrier member, one or more electrode contacts, and conductive pathways extending from each of the one or more electrode contacts which electrically connect the contacts to a stimulator unit. The conductive pathways may comprise any number of electrical conductors, such as a wire.
At block 904 a strain relief is formed in a conductive pathway. As discussed below, the strain relief may be formed in the conductive pathway using several methods. For example, a strain relief former tool in accordance with embodiments of the present invention may be used to form the strain relief. Also as described below, the strain relief may be formed at various different physical locations of the conductive pathway. As would be appreciated, the strain relief may be formed in the conductive pathway prior to the providing of an electrode contact. That is, in certain embodiments, step 904 may occur prior to, or concurrently with, step 902. As discussed below, in certain embodiments the strain relief is formed in the distal region of the conductive pathway.
At block 906, the distal end of the conductive pathway is attached to the electrode contact. As noted above, a variety of methods may be implemented to attach or join the distal end of the conductive pathway to the electrode contact. These methods may include, for example, resistance welding, wire bonding, crimping, laser welding, etc.
In the embodiments of
At block 904B a strain relief is formed in a conductive pathway. In the specific embodiments of
At block 906, the distal end of the conductive pathway is attached to the electrode contact. As noted above, a variety of methods may be implemented to attach the distal end of the conductive pathway to the electrode contact, such as resistance welding, wire bonding, crimping, laser welding, etc.
At block 904C a strain relief is formed in a conductive pathway. In the specific embodiments of
At block 906, the distal end of the conductive pathway is attached to the electrode contact. As noted above, a variety of methods may be implemented to attach the distal end of the conductive pathway to the electrode contact, such as resistance welding, wire bonding, crimping, laser welding, etc.
At block 904D a strain relief is formed in a conductive pathway. In the specific embodiments of
At block 906, the distal end of the conductive pathway is attached to the electrode contact. As noted above, a variety of methods may be implemented to attach the distal end of the conductive pathway to the electrode contact, such as resistance welding, wire bonding, crimping, laser welding, etc.
At block 908 a strain relief is formed in a conductive pathway using one of a variety of methods as described above with reference to
At block 906, the distal end of the conductive pathway is attached to the electrode contact via a contact joint. As noted above, a variety of methods may be implemented to attach the distal end of the conductive pathway to the electrode contact, such as resistance welding, wire bonding, crimping, laser welding, etc.
Method 900E includes the additional step at block 912 where the conductive pathway is secured to the electrode contact. Specifically, at block 912, a section of the conductive pathway substantially between the strain relief and the contact joint, and adjacent to the contact joint, is secured to the electrode contact. As described above with reference to
At block 910 a strain relief is formed in a conductive pathway. In the specific embodiments of
At block 906, the distal end of the conductive pathway is attached to the electrode contact via a contact joint. As noted above, a variety of methods may be implemented to attach the distal end of the conductive pathway to the electrode contact, such as resistance welding, wire bonding, crimping, laser welding, etc.
Method 900F includes the additional step at block 912 where the conductive pathway is secured to the electrode contact. Specifically, at block 912, a section of the conductive pathway substantially between the strain relief and the contact joint, and adjacent to the contact joint, the is secured to the contact. As described above with reference to
At block 954, the distal end of an elongate conductive pathway is attached to the electrode contact via a contact joint. Similar to the embodiments described above, a variety of methods may be implemented to attach the distal end of the conductive pathway to the electrode contact, such as resistance welding, wire bonding, crimping, laser welding, etc.
Method 950 includes the additional step at block 956 where the conductive pathway is secured to the electrode contact. Specifically, at block 956, a section of the conductive pathway adjacent to the contact joint is secured to the electrode contact. As described above with reference to
As noted, an electrode assembly in accordance with specific embodiments of the present invention includes several elements, such as a carrier member, a plurality of electrode contacts, and conductive pathways extending from each of the electrode contacts which electrically connect the contacts to a stimulator unit.
At block 1006 a strain relief is formed in a conductive pathway. As discussed below, the strain relief may be formed in the conductive pathway using several methods. For example, a strain relief former tool in accordance with embodiments of the present invention may be used to form the strain relief. Also as described below, the strain relief may be formed at various different locations of the conductive pathway.
At block 1008, the distal end of the conductive pathway is attached to the most proximal electrode contact that has not yet been attached to a conductive pathway. As noted above, a variety of methods may be implemented to attach or join the distal end of the conductive pathway to the electrode contact. These methods may include, for example, resistance welding, wire bonding, crimping, laser welding, etc.
At block 1010, a determination is made as to whether a conductive pathway has been attached to all desired contacts in the electrode array. If a conductive pathway has been attached to all desired contacts within the array, the method ends at block 1012. However, if a conductive pathway has not been attached to all desired contacts, the method returns to block 1006 where a strain relief is formed in an additional conductive pathway. Steps 1006, 1008 and 1010 are repeated until a conductive pathway has been attached to all electrode contacts in the array.
In certain embodiments of the present invention, conductive pathways are attached to all contacts in the electrode array. In alternative embodiments, an electrode assembly may include non-active contacts, (ie contacts which are not connected to pathways, but are used to perform various other functions) as well as active contacts (i.e. contacts used to deliver electrical stimulation signals). In such embodiments, the conductive pathways are attached to only active contacts.
At block 1018 a strain relief is formed in a conductive pathway. As discussed below, the strain relief may be formed in the conductive pathway using several methods. For example, a strain relief former tool in accordance with embodiments of the present invention may be used to form the strain relief. Also as described below, the strain relief may be formed at various different locations of the conductive pathway.
At block 1020, the distal end of the conductive pathway is attached to the provided electrode contact. As noted above, a variety of methods may be implemented to attach or join the distal end of the conductive pathway to the electrode contact. These methods may include, for example, resistance welding, wire bonding, crimping, laser welding, etc.
At block 1022, a determination is made as to whether additional contacts are desired. If additional contacts are not desired, the method ends at block 1024. However, if additional contacts are desired, the method proceeds to block 1026 where an additional contact is provided. In the specific embodiments of
As noted above, in certain embodiments of the present invention, conductive pathways are attached to all contacts in the electrode array. In alternative embodiments, an electrode assembly may include non-active contacts, as well as active contacts. In such embodiments, an additional decision may be included to determine if a provided contact is designated as active or non-active. If a contact is non-active, a conductive pathway is not attached thereto, and the method proceeds to provide another contact.
In accordance with embodiments of the present invention, once an electrode array or contact and conductive pathway arrangement is manufactured using one of the methods of the present invention, an electrode assembly incorporating the component(s) may be completed. Forming an electrode assembly may include various steps, including following the welding of the pathways to the desired contacts, placing silicone in the troughs of each contact and placing a stylet (PTFE coated wire) on top of the conductive pathways and the silicone in the troughs of the contacts. This may further include partially filling each contact trough with additional silicone. The whole assembly is then placed in an oven to cure the silicone. The assembly is then curved and moulded in a curved moulding die.
As noted above, embodiments of the present invention permit simple and automated manufacturing methods of small electrode assemblies that have decreased sensitivity to flexing/bending which may occur during normal use of the assembly.
In the illustrative embodiments of
In the embodiments of
At block 1121, the holding tool is used to position the conductive pathway within a strain relief former. Once positioned in the strain relief former, the conductive pathway is released by the holding tool. At block 1122, the strain relief former is used to form a planar strain relief in the distal region of the conductive pathway. As described below with reference to
As would be appreciated, strain reliefs that are in three dimensions may be difficult to form, thus making it difficult or impossible to automate the formation of such reliefs. As such, the manufacture of the wiring and connector components in which three dimensional reliefs are included is labor intensive and specialized manual craft. Also, three-dimensional strain reliefs must be rotated to confirm shape compliance further limiting manufacturing options.
As described above, in certain embodiments of the present invention, the strain relief is optimized to facilitate the automated forming of the strain relief. Automation of the strain relief formation has significant advantages in the form of reduced costs and the formation of consistent strain reliefs that are do not vary as a result of human errors. For example, in certain embodiments, the strain relief comprises a planar strain relief that is in two dimensions. Because the relief is only within a two-dimensional plane, the formation of the strain relief is less complicated than a three-dimensional relief, thereby facilitating automation of the strain relief formation.
Furthermore, as described below, in embodiments of the present invention, the physical shape of the relief is selected to facilitate the automated formation of the strain relief. For example, in certain embodiments, a strain relief comprises multiple planar turns or bends of wire. The turns are largest at the most distal end, and decrease in size towards the proximal end of the relief. This decreasing shape of the turns facilitates the automation process. Other alterations to the shape of the strain relief to facilitate automation are within the scope of the present invention.
Partial or full automation of the process used to manufacture any elements of an electrode assembly, such as a contact or conductive pathway arrangement, has numerous advantages.
In operation, a wire 1242 is placed between first and second portions 1202, 1204. The first and second portions are then closed so that surfaces 1224, 1226 approach one another. As surfaces 1224, 1226 approach one another, a non-linear section of wire 1242 is formed, referred to as strain relief 1230. Furthermore, in the embodiments of
Strain relief 1230 formed by strain relief former 1200A comprises a non-linear section of wire 1242. In particular, strain relief 1230 comprises a full turn 1211 of wire 1242, and a half turn 1213 of the wire. As noted above, a full turn of wire or conductive pathway refers to a section of wire/pathway that travels a first direction for a first distance, has a general U-shaped portion, and which extends away from the U-shape for a second distance which is approximately the same as the first distance. In contrast, a half turn refers to a section of wire that only comprises a U-shaped potion.
As noted above, in embodiments of the present invention the turns of a strain relief, such as strain 1230, are asymmetric in size. In some embodiments, each distally positioned turn is larger than the next most proximal turn. In other embodiments, each distally positioned turn is smaller than the next most proximal turn. The size of a turn refers to the change in length of wire over the original longitudinal distance of the wire. It should be appreciated that an increase in size increases the largest dimensions of the turn perpendicular to the longitudinal axis of wire 1242.
As noted, the asymmetrical size of turns 1211 and 1213 is important to facilitate the automated formation of strain relief 1230 by permitting the formation to occur by a single action tool. Specifically, as shown in
If turns 1211 and 1213 were the same size, members 1201 and 1207 would contact the wire at the same time. This would pull wire 1242 at two locations simultaneously and place a tension on wire 1242 that would likely break to damage wire. In contrast, the delay in the formation of turn 1213 provides the ability to form multiple turns without placing the undesired tension on wire 1242.
As would be appreciated, in order to form multiple turns of wire having the same size, a multi-stage formation tool would be required. In particular, a different tool would be needed to form each turn in the relief so as to prevent breakage of the wire due to tensile forces. As such, the wire must be moved from tool to tool to complete the procedure. As would be appreciated, the need to realign the wire within each tool is disadvantageous. As noted, embodiments of the present invention avoid the need for a multistage tool and form multiple turns with a single action tool.
As noted above with reference to
As noted, the embodiments of
The longer the stored length of the wire within strain relief, the greater the change in length allowed and the more effective the stain relief is. However, the bend radius of a wire is limited, thus limiting the amount of wire that may be stored for use as the strain relief. Bend radius refers to the fact that when a wire is bent, the outside of the bend is under tensile stress and the inside under compressive stress. If the bend radius is too small then weaknesses occur in the bend zone. Thus, the bend radius is limited to a ratio of the thickness of the wire. For example, a wire used in certain embodiments of the present invention comprises a Pt/Ir wire, and has a diameter of 25 microns having a bend radius of approximately 100 microns. As would be appreciated, changing the temper of the wire (e.g. annealing) would affect the acceptable bend radius and the properties of the strain relief. Furthermore, wires having different properties such as different cross sections (eg rectangular for ‘machined foil strips’) or different materials/alloy combinations (eg using Pt not Pt/Ir) would also have different bend radius limitation. Therefore, strain former tools 1200A, 1200B are configured to place bends in wire 1242 are within bend radius limitations.
As noted above in
As shown, wire 1442 is aligned with an axis 1420. For ease of illustration, axis 1420 is shown as a horizontal axis. However, it would be appreciated that axis 1420 may be disposed at a number of angles. For example, in certain embodiments, axis 1420 may be disposed at an angle of approximately 15 degrees from a horizontal axis.
In the embodiments of
During the formation of a strain relief in accordance with certain embodiments of the present invention, a wire is secured at both sides of a strain relief former. However, in other embodiments of the present invention, the wire may be secured only at one side of the former, or alternatively, at neither side of the former.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. All patents and publications discussed herein are incorporated in their entirety by reference thereto
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008903143 | Jun 2008 | AU | national |
| 2008903144 | Jun 2008 | AU | national |
| 2008903145 | Jun 2008 | AU | national |
| 2008903146 | Jun 2008 | AU | national |
The present application is a National Stage application of International Patent Application No. PCT/US2009/043946, filed May 14, 2009, and claims priority from Australian Patent Application Nos. 2008903143, 2008903144, 2008903145, 2008903146, each filed Jun. 20, 2008. The content of these applications is hereby incorporated by reference herein. The contents of International Patent Application No. PCT/US2009/043959, filed May 14, 2009, are also incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US09/43946 | 5/14/2009 | WO | 00 | 2/16/2011 |
