Patent Abstract:
Apparatus connect electrically conductive wire to a miniature, implantable sensor or stimulator device for detecting electrical signals or stimulating living tissue. The implantable device has an electrically conductive end on its case which is intimately connected to a doorknob electrode for communicating electrical signals between the living tissue and the device by a biocompatible wire. A spring clip removably attaches to the doorknob electrode so that the wire may be easily attached to the doorknob electrode during surgery. An insulating rubber boot, which may be silicone, surrounds the case end, doorknob electrode, and spring clip to isolate the living tissue from the conductive components. The components are biocompatible materials.

Full Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a divisional of U.S. patent application Ser. No. 09/971,849, filed Oct. 4, 2001, now U.S. Pat. No. 6,947,782 B2, issued Sep. 20, 2005; which claims the benefit of U.S. Provisional Application No. 60/299,106, filed on Jun. 18, 2001. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a prosthetic medical device for connecting electrical conducting wires to a miniature implantable device to minimize risk to the living tissue. 
   2. Description of Related Art including Information Disclosed under 37 CFR 1.97 and 1.98 
   Neurological disorders are often caused by neural impulses failing to reach their natural destination in otherwise functional body systems. Local nerves and muscles may function, but, for various reasons, such as injury, stroke, or other cause, the stimulating nerve signals do not reach their natural destination. For example, paraplegic and quadriplegic animals have intact nerves connected to functioning muscles and only lack the brain-to-nerve link. Electrically stimulating the nerve or muscle can provide a useful muscle contraction. 
   Further, implanted devices may be sensors as well as stimulators. In either case, difficulties arise both in providing suitable, operable stimulators or sensors which are small in size and in passing sufficient energy and control information to or from the device, with or without direct connection, to satisfactorily operate them. Miniature monitoring and/or stimulating devices for implantation in a living body are disclosed by Schulman, et al. (U.S. Pat. No. 6,164,284), Schulman, et al. (U.S. Pat. No. 6,185,452), and Schulman, et al. (U.S. Pat. No. 6,208,894) all incorporated in their entirety herein by reference. 
   It must be assured that the electrical current flow does not damage the intermediate body cells or cause undesired stimulation. Anodic or cathodic deterioration of the stimulating electrodes must not occur. 
   In addition, at least one small stimulator or sensor disposed at various locations within the body may send or receive signals via electrical wires. The implanted unit must be sealed to protect the internal components from the body&#39;s aggressive environment. If wires are attached to the stimulator, then these wires and the area of attachment must be electrically insulated to prevent undesired electric signals from passing to surrounding tissue. 
   Miniature stimulators offer the benefit of being locatable at a site within the body where a larger stimulator cannot be placed because of its size. The miniature stimulator may be placed into the body by injection. The miniature stimulator offers other improvements over larger stimulators in that they may be placed in the body with little or no negative cosmetic effect. There may be locations where these miniature devices do not fit for which it is desired to send or receive signals. Such locations include, but are not limited to, the tip of a finger for detection of a stimulating signal or near an eyelid for stimulating blinking. In such locations, the stimulator and its associated electronics are preferably located at a distance removed from the sensing or stimulating site within the body; thus creating the need to carry electrical signals from the detection or stimulation site to the remote miniature stimulator, where the signal wire must be securely fastened to the stimulator. 
   Further, the miniature stimulator may contain a power supply that requires periodic charging or require replacement, such as a battery. When this is the case, the actual stimulation or detection site may be located remotely from the stimulator and may be located within the body, but removed a significant distance from the skin surface. By having the ability to locate the miniature stimulator near the skin while the stimulation site is at some distance removed from the skin, the miniature stimulator and its associated electronics can be more effectively replaced by a surgical technique or more efficiently recharged through the skin by any of several known techniques, including the use of alternating magnetic fields. If the electronics package is replaced surgically, then it is highly desirable to have the capability to reconnect the lead wires to the miniature stimulator via an easy, rapid and reliable method, as disclosed herein. 
   BRIEF SUMMARY OF THE INVENTION 
   The instant invention relates to an apparatus for connecting an electrically conductive wire to a miniature, implantable sensor or stimulator. A spring clip connector adapted to receive a doorknob electrode for communicating electrical signals between living tissue and an implantable miniature device that is configured for monitoring and/or affecting body parameters, has a prong for removably grasping the doorknob electrode to make a connection to an electrically conductive wire that has two ends, a first end for electrical coupling to a selected portion of the living tissue and a second end for attachment to the spring clip, where the spring clip is comprised of a biocompatible material. 
   The spring clip connector may be titanium, titanium alloy, platinum, iridium, platinum-iridium, stainless steel, tantalum, or niobium. An insulating rubber boot may surround the doorknob electrode and spring clip. The rubber boot may be silicone. 
   The spring clip connector may be a material selected from the group consisting of titanium, titanium alloy, platinum, iridium, platinum-iridium, stainless steel, tantalum, or niobium. 
   The doorknob electrode may be titanium, titanium alloy, platinum, iridium, platinum-iridium, stainless steel, tantalum, or niobium. 
   The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to provide an implantable miniature stimulator having at least one electrode. 
   It is an object of the invention to provide a method of connecting at least one wire to a miniature stimulator in a body. 
   It is an object of the invention to electrically insulate the electrode of an implantable miniature stimulator that is connected to an electrical wire from the environment in which it is implanted. 
   Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  illustrates a perspective view of the miniature stimulator with a threaded connector and nut. 
       FIG. 2  illustrates a perspective view of the miniature stimulator with a bayonet connector and nut. 
       FIG. 3  illustrates a perspective view of the miniature stimulator with a pin connector and nut. 
       FIG. 4  illustrates a perspective view of the smooth nut with a flare nut cap. 
       FIG. 5  is a cross-section through the flare nut wire insertion. 
       FIG. 6  is a cross-sectional view of the smooth cap with flare insertion. 
       FIG. 7  is a longitudinal section through the protective nut showing an offset mounting hole. 
       FIG. 8  is a cross-section through the protective nut showing the offset mounting hole. 
       FIG. 9  illustrates a stimulator with a hole and pin electrode. 
       FIG. 10  illustrates a stimulator with a hole and pin electrode and an electrode plug. 
       FIG. 11  is a longitudinal cross-section of a threaded hole electrode with plug. 
       FIG. 12  is a longitudinal cross-section of a threaded pin electrode with nut. 
       FIG. 13  is a longitudinal cross-section of a threaded pin electrode with nut and spade connector. 
       FIG. 14  illustrates a spade connector. 
       FIG. 15  illustrates a spade connector attached to a wire. 
       FIG. 15A  illustrates a detailed section of the crimp of  FIG. 15 . 
       FIG. 15B  illustrates a detailed section of an alternate crimp of  FIG. 15 . 
       FIG. 16  is a longitudinal cross-section of an electrode hole with a plug and crush lip. 
       FIG. 17  illustrates a C-clamp. 
       FIG. 18  illustrates a pin electrode with a wire inserted. 
       FIG. 19  illustrates a protective nut with a crush lip. 
       FIG. 20  is a longitudinal section through threaded insert with a flare attachment. 
       FIG. 21  is a perspective view of a stimulator in combination with a flare nut. 
       FIG. 22  is a longitudinal section showing the flare nut with a rubber boot. 
       FIG. 22A  is a section showing tie interaction with the rubber boot of  FIG. 22 . 
       FIG. 23  is a top view of a disk-shaped miniature stimulator with electrodes. 
       FIG. 24  is a side view of a disk-shaped miniature stimulator with electrodes. 
       FIG. 25  illustrates a miniature stimulator annular electrode and a section through the annular nut. 
       FIG. 26  is an end view of the miniature stimulator with annular electrodes. 
       FIG. 27  is an end view of the annular nut. 
       FIG. 28  is a longitudinal section through a miniature stimulator with annular electrodes and a section through the annular nut. 
       FIG. 29  illustrates an end view of a plug with wires. 
       FIG. 30  is a longitudinal cross-section through a plug with wires installed in a hollow miniature stimulator. 
       FIG. 31  illustrates a perspective view of an electrically conductive doorknob shaped electrode with spring clip connector and wire. 
       FIG. 32  is a perspective view of the electrically conductive doorknob shaped electrode. 
       FIG. 33  is a perspective view of the spring clip connector. 
       FIG. 34  is a longitudinal section through the doorknob shaped connector with a wire and rubber boot. 
       FIG. 35  is a longitudinal section through the doorknob shaped connector with crimped connector a wire and rubber boot. 
       FIG. 36  is longitudinal section through the snap-on cap connector with rubber boot. 
       FIG. 37  is longitudinal section through the elongated snap-on cap connector with rubber boot. 
       FIG. 37A  details the tooth interaction with the slip-on cap of  FIG. 37 . 
       FIG. 38  is longitudinal section through the flat-bottomed slot connector with rubber boot. 
       FIG. 39  is a perspective view of the flat-bottomed slot connector. 
       FIG. 40  is a perspective view of the flat-bottomed snap-on cap. 
       FIG. 41  is a cross-section of the flat-bottomed slot connector in the engaged position. 
       FIG. 42  is a cross-section of the flat-bottomed slot snap-on cap in the disengaged position. 
       FIG. 43  is a hand showing placement of an implantable miniature device with a wire lead that carries electrical signals to a fingertip. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An implantable miniature stimulator  2  is illustrated in  FIG. 1 .  FIG. 43  represents a typical placement of the implantable miniature stimulator  2  at a location that is remote from the site that is to be stimulated, in this case a fingertip, where an electrically conductive wire  38  carries the electrical signal to an electrode  39  at the stimulation site. Typical dimensions for this device are about 5 to 60 mm in length and about 1 to 6 mm in diameter. (See, for example, U.S. Pat. Nos. 6,164,284, 6,185,452, and 6,208,894 which are incorporated herein by reference in their entirety.) While element  2  is generally described as a stimulator, it is recognized that the present invention is equally applicable when element  2  is operable as a sensor or as a stimulator and a sensor. Stimulator  2  includes insulating case  4 , which typically is hollow and contains an electronics package and a power source, such as a battery, capacitor, magnetic field to electricity converter, and electrically conductive case ends  6 , each of which has an electrically conductive electrode  8  which conducts electrical signals from a stimulator and/or to a sensor, depending upon the design and function of that particular miniature stimulator  2 . Stimulator  2  may have at least one electrode, e.g., 2-8 or more, depending upon its particular design and function, although, for illustrative purposes, only two electrodes are shown in  FIG. 1 . Electrically conductive electrodes  8  are shown threaded in  FIG. 1 , although alternate embodiments are shown in other figures and are discussed herein. 
   Insulating case  4  contains the electronics, which may include a battery or other energy storage device and signal generating or receiving circuitry and is made of an electrically insulating material that is capable of being hermetically sealed and that is also biocompatible, such as plastic or ceramic. The plastic may be epoxy, polycarbonate, or plexiglass. The ceramic may be alumina, glass, titania, zirconia, stabilized-zirconia, partially-stabilized zirconia, tetragonal zirconia, magnesia-stabilized zirconia, ceria-stabilized zirconia, yttria-stabilized zirconia, or calcia-stabilized zirconia, and in a preferred embodiment, insulating case  4  is yttria-stabilized zirconia, although other insulating materials may also be used. The insulating case  4  must be a material that is biocompatible as well as capable of being hermetically sealed, to prevent permeation of bodily fluids into the case. 
   The electrically conductive case end  6  is preferably a biocompatible, non-corrosive material, such as titanium or a titanium alloy, although other metals such as platinum, iridium, platinum-iridium, stainless steel, tantalum, niobium, or zirconium may be used. The preferred material is Ti-6 Al-4 V. An alternate preferred material is platinum-iridium. 
   If any electrically conductive electrode is not being used while the stimulator is in the body, then the electrode may be insulated to prevent stimulation of nearby tissue. Protective nut  10  is either an insulator or an electrically conductive conductor. If it is an electrical conductor, then it is an extension electrode of electrically conductive case  6 . It is placed over the unused electrically conductive electrode  8  such that protective nut threaded hole  12  is tightly screwed onto threaded electrically conductive electrode  8 . In a preferred embodiment, the threads on threaded electrically conductive electrode  8  are 0 80 threads. In order to avoid growth of tissue into joints, such as the joint formed between protective nut  10  and electrically conductive case end  6 , it is preferable that any gap be less than 7 microns. 
   An alterative embodiment is illustrated in  FIG. 2  where bayonet electrode  14  is covered by protective nut  15  that contains bayonet mount  16 . Yet another embodiment of miniature stimulator  2  is illustrated in  FIG. 3 , where electrically conductive electrode  8  is now stud electrode  21 , a smooth stud, which has electrode through-hole  18  passing radially through and intersecting with the longitudinal axis of stud electrode  21 . Stud protective nut  19  is placed onto stud electrode  21  such that protective nut mounting hole  20  fits over stud electrode  21  while protective nut through-hole  22  is aligned with electrode through-hole  18 . Protective nut through-hole  22  is positioned such that it passes radially through and intersects with the longitudinal axis of protective nut  19  and such that nut  19  fits very snugly against electrically conductive case end  6 . Breakaway pin  24  is placed into protective nut through-hole  22  and into electrode through-hole  18 . After alignment of protective nut  19  onto electrode  21  is complete, the protruding portion of breakaway pin  24  is broken off and discarded. 
   A preferred method of attaching an electrically conductive wire  38  to a miniature stimulator  2  (see  FIG. 1 ) is illustrated in  FIGS. 4 ,  5 , and  6  wherein flare nut  26  is comprised of protective nut  28 , which contains flare nut mounting hole  30 . Threaded flare nut mounting hole  30  is positioned over electrode  8  (see  FIG. 1 ) and tightened by screwing onto the threads. Flare nut  26  also contains flare nut wire receptor  32  which has flare  34  on its extension pointed away from protective nut  28 . Because of the small diameter of wire used in this application, flare  34  is provided for ease of placement of electrically conductive wire  38  into flare  34 . Offset through-hole  36  passes through flare nut wire receptor  32  in a plane that is perpendicular to the longitudinal axis of flare nut  26 . Offset through-hole  36  preferably does not intersect with the longitudinal axis of nut  26 , but is intentionally offset to penetrate wire insulator  41  (see  FIG. 6 ) and to intersect with the outer diameter of wire conductor  40 . Thus when a pin, not illustrated, is placed in offset through-hole  36 , wire conductor  40  is contacted, creating an electrically conductive path between wire conductor  40  and protective nut  28 . 
   The cross-sectional view of  FIG. 5  illustrates the offset alignment of offset through-hole  36  with respect to the longitudinal axis of flare nut wire receptor  32 . Wire conductor  40  is intersected by offset through-hole  36  such that wire insulator  41  will be penetrated and wire conductor  40  will be contacted by a pin inserted in offset through-hole  36 . Electrically conductive wire  38 , shown in  FIG. 6  is comprised of wire conductor  40  within wire insulator  41 . Alternately, wire insulator  41  may be stripped from an end portion of wire conductor  40 , to help insure good electrical contact between conductor  40  and flare nut wire receptor  32 . 
   In a preferred embodiment, wire conductor  40  is a highly conductive metal that is also benign in the body, such as MP35, although stainless steel or an alloy of platinum-iridium may also be used. Preferably, the wire has a diameter of approximately 0.003 inches. It is contained in wire insulator  41  to electrically isolate it from the body tissue and fluids and, in a preferred embodiment, wire insulator  41  is Teflon-coated silicone. 
   An alternate method of attaching an electrically conductive wire (not shown) to electrically conductive case end  6  is shown in  FIG. 7 , where an electrically conductive wire is attached to smooth stud electrode  21  by placing smooth protective nut  42  over stud electrode  21  by aligning protective nut mounting hole  43  with stud electrode  21  and engaging them. Offset through-hole  44  is of a diameter that allows an insulated wire to pass therethrough and it is aligned such that when smooth protective nut  42  is pushed onto stud  21 , the electrically conductive wire is contacted and crushed, thereby making electrical contact between the electrically conductive wire and stud electrode  21 . A cross-sectional view through protective nut  42 , illustrated in  FIG. 8 , shows the alignment of offset through-hole  44  with respect to protective nut mounting hole  43 . Smooth protective nut  42  is retained on stud  21  by virtue of the frictional force generated by a crushed wire present in offset through-hole  44  as protective nut  42  is placed on stud electrode  21 . 
   In an alternate embodiment, shown in  FIG. 9 , miniature stimulator  2  has at one end threaded electrically conductive electrode  8  and at the other end threaded electrode hole  46 . Alternate embodiments contain various combinations of electrically conductive electrodes  8  and electrode holes  46 .  FIG. 9  illustrates one such combination of dissimilar electrodes. As discussed previously, if an electrode is unused, then it must be covered and protected to prevent tissue damage or undesirable tissue growth into the stimulator. If threaded electrode hole  46  is unused, then it is filled with electrode plug  48 , which is screwed tightly into hole  46 , as illustrated in  FIG. 10 . 
   A further method of attaching an electrically conductive wire  38  (not illustrated) to electrically conductive case end  6  is illustrated in  FIG. 11 , where threaded electrode hole  46  mates with smooth nut  52  by inserting threaded insert  50  into threaded electrode hole  46 . As nut  52  is tightened, an electrically conductive wire, not illustrated, that has previously been inserted in smooth nut through-hole  54  is crushed between electrically conductive case end  6  and nut crush lip  56 , thereby making contact between the electrically conductive wire and electrically conductive case end  6 . Smooth nut through-hole  54  retains the wire in position and assures that the wire is secured in place until smooth nut  52  is fully tightened. 
   Illustrated in  FIG. 12  is an alternate embodiment of a method of attaching an electrically conductive wire to a miniature stimulator  2 , wherein electrically conductive case end  6  has threaded electrically conductive electrode  8  attached thereto. Electrically conductive electrode  8  contains electrode through-hole  18  located proximate to electrically conductive case end  6 . Protective nut  10  is attached to threaded electrically conductive electrode  8  by screwing electrically conductive electrode  8  into protective nut threaded hole  12 . An electrically conductive wire, not shown, is held in place by placing it through electrode through-hole  18 . The wire makes electrical contact with electrically conductive case end  6  by virtue of being crushed between electrically conductive case end  6  and protective nut  10  by nut crush lip  56 . 
   A further embodiment of methods to attach an electrically conductive wire (not illustrated) to assure electrical conductivity between the electrically conductive wire and the electrically conductive case end  6  is illustrated in  FIG. 13 , where spade clip  58 , which is attached to an electrically conductive wire (not illustrated), is securedly fastened between protective nut  10  and electrically conductive case end  6 . 
   Spade clip  58  is shown in  FIG. 14  with tab  60  configured to attach to electrically conductive wire  38 . Electrically conductive wire  38 , is placed in tab  60  with wire insulator  41  stripped from an end portion of the electrically conductive wire  38 , thereby exposing wire conductor  40  for electrical contact with tab  60 . Tab  60  is wrapped around electrically conductive wire  38  so as to assure that electrically conductive wire  38  is securely attached to spade clip  58  by wrapped tab  60 , which has crimp  70 , as shown in  FIG. 15 . 
     FIG. 15  illustrates spade clip  58  with electrically conductive wire  38  attached to spade clip  58  and retained by crimp  70 . Opening  62  in spade clip  58  is configured to approximate the diameter of electrically conductive electrode  8  (see  FIG. 13 ) such that spade clip  58  fits over electrically conductive electrode  8  (not illustrated). In a preferred embodiment, tab  60  and electrically conductive wire  38  are oriented at a right angle to spade clip  58 , thus assuring that electrically conductive wire  38  is parallel to the longitudinal axis of miniature stimulator  2 , thereby minimizing stresses in the wire.  FIGS. 15A and 15B  illustrate detailed alternate crimp  70  attachment methods of securedly fastening wire conductor  40  to spade clip  58 . 
   An alternate embodiment, illustrated by cross-sectional view in  FIG. 16 , has a wire (not shown) placed through smooth nut through-hole  54 , which is located proximate to smooth nut  52 . As smooth nut  52  is tightened into threaded electrode hole  46  by inserting threaded insert  50  into threaded electrode hole  46 , the wire is crushed between end crush lip  72  and cap  52 , thereby making electrical contact between the wire and electrically conductive case end  6 . The difference between the method of wire attachment illustrated in  FIG. 11  and that shown by  FIG. 16  is the relocation of nut crush lip  56  from the protective nut  10  of  FIG. 11  to electrically conductive case end  6 , as end crush lip  72  in  FIG. 16 . 
   Illustrated in  FIGS. 18 and 19  is a further embodiment of a method of attaching an electrically conductive wire (not shown) to miniature stimulator  2 , wherein smooth electrode  76  contains no threads and also has offset electrode through-hole  75 , which is aligned to lie in a plane that is perpendicular to the longitudinal axis of miniature stimulator  2  to intersect with the outer diameter of wire conductor  38 , such that when a pin (not shown) is placed in through-hole  75 , it will contact wire conductor  40 , either by penetrating wire insulator  41  or by contacting the wire conductor  40  directly, if wire insulator  41  has been stripped from that area. Protective nut  10 , shown in  FIG. 19 , illustrates nut crush lip  56 , and also illustrates offset protective nut mounting hole  77 , which aligns with offset electrode through-hole  75 , thereby allowing a pin (not shown) to pass through both offset protective nut mounting hole  77  and offset electrode through-hole  75 . 
   A further embodiment, illustrated by cross-sectional view in  FIG. 20 , is similar to the embodiment presented in  FIG. 4 , but with electrically conductive case end  6  having threaded electrode hole  46  in place of flare nut mounting hole  30 . Threaded insert  50  is screwed into threaded electrode hole  46 , thereby securing protective nut  28  to electrically conductive case end  6 . An electrical connection between electrically conductive wire  38  is made by stripping wire insulator  41  from the end of wire  38  thus exposing wire conductor  40 . Conductor  40  is inserted into flare nut wire receptor  32  using flare  34  as a guide. Wire insulator  41  is stripped such that, when wire conductor  40  is inserted fully into flare nut wire receptor  32 , wire insulator  41  extends approximately one-quarter of the length of receptor  32  into receptor  32 . Wire  38  is securedly attached inside receptor  32  by crimping receptor  32  to wire conductor  40 . 
   An alternate method of attaching protective nut  28  to smooth stud electrode  21  is illustrated in  FIG. 21 . While the preferred method of attaching the two components is by screwing them together, as illustrated in  FIGS. 4 and 20 , in the instant embodiment, electrically conductive case end  6  has stud electrode  21  attached thereto, which has no threads. Protective nut  28  slips snugly over stud electrode  21  until electrically conductive case end  6  is located touching adjoining protective nut  28 . As previously illustrated in  FIG. 20  and as discussed above, wire  38  and its conductor  40  and wire insulator  41  are securely fitted inside flare nut wire receptor  32  by using flare  34  as a guide. Electrically conductive wire  38  is secured by crimping flare nut wire receptor  32  onto wire conductor  40  (see  FIG. 21 ). Protective nut  28  is secured to stud electrode  21  by placing C-clip  74  (see  FIG. 17 ) over protective nut  28  such that protective nut  28  is partially deformed, thereby creating a secure attachment between stud electrode  21  and protective nut  28 . 
   The preferred method of assuring electrical insulation between electrically conductive case end  6 , electrically conductive electrode  8 , protective nut  28 , and wire  38 , as illustrated in  FIG. 22 , is to cover the electrically conductive case end  6  and other parts with rubber boot  82 . Rubber boot  82  is made of a flexible insulating material that is biocompatible, such as silicone. Its purpose is to provide electrical insulation such that stray electrical signals do not pass between surrounding tissue and any electrically conductive part of the device. Rubber boot  82  is secured to the device, preferably by tying it in place with ties  84 . A sufficient number of ties  84  are placed by the surgeon to assure that that the rubber boot  82  will not move. It is preferred that at least one tie  84  and, preferably two or more ties  84 , be placed on rubber boot  82  to secure rubber boot  82  to insulating case  4 , so as to electrically insulate electrically conductive case end  6  from the living tissue.  FIG. 22A  illustrates a typical tie  84  interacting with rubber boot  82 , so as to establish and maintain a hermetic seal. Alternate methods of attaching rubber boot  82  include the use of ridges inside rubber boot  82 , clamps over rubber boot  82 , silicone adhesive inside rubber boot  82 , ridges on the outside of insulating case  4 , a male notch with matching female indentation forming an O-ring seal, and the tight fit of rubber boot  82  over the device, either with or without internal ridges. 
   An alternate configuration to miniature stimulator  2 , previously illustrated in  FIG. 1 , is miniature disk stimulator  86 , which is illustrated in  FIGS. 23 and 24 . Disk  88  is preferably comprised of insulating material having at least one electrically conductive electrode  90 . Two electrodes are illustrated in  FIGS. 23 and 24 , but alternate arrangements have at least one, e.g., 1 to 8 or more, electrodes. Electrode  90  is hermetically bonded to disk  88 . Electrode  90  can be one or more tabs as shown in  FIG. 23 , or it can be one or more flush electrodes (not illustrated) that are mounted on the surface of disk  88 . While the tabs  90  that are illustrated in  FIGS. 23 and 24  project from the surface of the insulating disk  88 , the tabs  90  can equally well not project from the surface of insulating disk  88  and may be contiguous with the surface such that they do not project above the surface. The methods of connecting a wire to the miniature stimulator that have been previously discussed are equally applicable to miniature disk stimulator  86 , as well as to other configurations. The dimensions of disk  88  are about 5 to 40 mm diameter and about 1 to 6 mm thick. Electrically conductive electrode  90  is preferably made of an electrical conductor that is biocompatible and corrosion resistant, such as platinum, iridium, platinum-iridium, tantalum, titanium or a titanium alloy, stainless steel, niobium, or zirconium. Disk  88  is made of an electrical insulator that is biocompatible, such as ceramic, glass, or plastic. 
     FIG. 25  illustrates an alternate annular electrode arrangement on the end of miniature stimulator  2 . At least one annular electrode may be used, e.g., four annular electrodes  92  are illustrated in  FIG. 25 . Each annular electrode  92  is capable of carrying an independent electrical signal and is electrically isolated from the other electrodes. The signal from or to stimulator  2  passes along electrically conductive wires  38 , where each electrically conductive wire  38  carries an independent signal and is electrically isolated from the others. Each electrically conductive wire  38  corresponds with and is connected to one annular electrode  92  by means of its connecting to toroidal spring  98 . Alternatively, toroidal spring  98  may be a semi-circular spring. Annular cap  94  contains toroidal springs  98 . Electrically conductive wires  38  pass through holes in the end of cap  94 . The internal diameter of annular cap opening  96  approximates but is slightly larger than the outer diameter of stimulator  2 . To make a connection between annular electrode  92  and toroidal spring  98 , annular cap  94  is pushed in a longitudinal direction along the axis of stimulator  2  until it is fully engaged in a position such that electrical contact is made between annular electrode  92  and a corresponding toroidal spring  98 . Each toroidal spring  98  is preferably retained inside annular cap  94  by an annular recession inside annular cap  94  such that during engagement of stimulator  2  with annular cap  94 , the toroidal spring  98  is forced into the recession, thereby allowing room for smooth engagement of the parts. The alignment of toroidal spring  98  and annular electrode  92  is such that each toroidal spring  98  contacts only one corresponding annular electrode  92 . 
     FIG. 26  illustrates the case end  100  of stimulator  2  and  FIG. 27  illustrates the end view of annular cap  94 . A cross-sectional view of annular electrode  92  is illustrated in  FIG. 28 . 
   Another embodiment for making an electrical connection to miniature stimulator  2  is illustrated in  FIGS. 29 and 30 .  FIG. 29  illustrates an end view of electrode plug  104  (see  FIG. 30 ) showing four electrically conductive wires  38  passing into the center of electrode plug  104  through potting material  106 . The potting material provides a secure, hermetic seal for wires  38  to pass into miniature stimulator core  102 , as illustrated in  FIG. 30 . 
     FIG. 30  illustrates a longitudinal view in cross-section of miniature stimulator  2  comprising insulating case  4 , electrically conductive case end  6 , electrode plug  104 , and potting material  106 . Electrode plug  104  is made of a biocompatible material such as titanium and is attached by weld  105  to electrically conductive case end  6 , thereby forming a hermetic seal. 
   Another embodiment for making an electrical connection to a miniature stimulator  2  is illustrated in  FIG. 31  where doorknob electrode  108  is intimately attached to electrically conductive case end  6 . The doorknob electrode is made of a material that is electrically conductive and biocompatible, such as titanium. 
   Spring clip  110  is preferably a clip made of titanium which has two or more, and preferably three or four prongs. Wire insulator  41  is stripped from the end of wire  38  thereby exposing wire conductor  40 . Wire conductor  40  is preferably attached to spring clip  110  by strain relief weld  112 . Strain relief weld  112  helps to relieve strain in wire conductor  40  by virtue of being oriented perpendicular to the longitudinal axis of miniature stimulator  2 . Further strain relief is provided in wire conductor  40  by virtue of it being tightly coiled inside wire insulator  41  thereby forming wire strain relief  114 . The inside of wire insulator  41  is fill material  115 , which is preferably soft silicone, to minimize infiltration of body fluids and other tissue inside wire  38 . 
   A perspective view of doorknob electrode  108 , showing its end attached to electrically conductive case end  6 , is illustrated in  FIG. 32 .  FIG. 33  illustrates a perspective view of spring clip  110  showing the four prongs that slip over doorknob electrode  108  to form an electrical connection. 
     FIG. 34  illustrates spring clip  110  together with electrically conductive wire  38 , which in turn is attached by strain relief weld  112  to wire conductor  40 . Spring clip  110  is shown in its attached position on doorknob electrode  108 . Rubber boot  82  is securely fastened to the device with ties  84  to completely cover electrically conductive case end  6 , doorknob electrode  108 , wire conductor  40  and a portion of wire insulator  41 , thus electrically insulating the body tissue from electrical signals. 
   An alternate embodiment is presented in  FIG. 35 , which is similar to the connection device presented in  FIG. 34  except that connector crimp  118 , which is selected from the group of biocompatible materials, and is preferably platinum metal, is placed over the end of electrically conductive wire  38  so as to cover a portion of wire insulator  41  and stripped wire conductor  40 . Connector crimp  118  is attached to electrically conductive wire  38  by crimping it onto wire  38 . 
   A preferred embodiment is shown in  FIG. 36  in which slip-on cap  122  has a slightly larger internal diameter of a portion of slip-on cap  122  such that it slips over the outer diameter of insulating case  4 . Snap-on cap  120  has at least one flexible member  130  having a tooth  135  on each flexible member  130 . Tooth  135  engages the edge of electrically conductive slip-on cap  122 , as illustrated in  FIG. 37A , and holds snap-on cap  120  tightly in place. Electrical conductivity is achieved between electrically conductive wire  38  and electrically conductive slip-on cap  122  by spring disk  125  holding enlarged end of wire  140  tightly in contact with electrically conductive slip-on cap  122  when snap-on cap  120  is in place. Rubber boot  82  provides electrical insulation by covering electrically conductive slip-on cap  122 , snap-on cap  120 , and a portion of electrically conductive wire  38 . 
   An alternate embodiment is shown in  FIG. 37  in which snap-on cap  120  is elongated and slotted on the end opposite tooth  135 . When slotted elongated end  123  is squeezed, flexible members  130  are levered outward and tooth  135  is thereby disengaged from the edge of slip-on cap  122 .  FIG. 37A  illustrates the interaction of tooth  135  with slip-on cap  122  such that snap-on cap  120  is securedly fastened to slip-on cap  122 . 
   An alternate embodiment is shown in  FIG. 38  in which electrically conductive case end  6  contains at least one angled flat  150  to allow rotatable cap tooth  136  of rotatable cap  133  to slide smoothly onto the end of electrically conductive case end  6  and to facilitate alignment of rotatable cap tooth  136  with flat-bottomed slot  145 . Electrically conductive case end  6  has at least one flat-bottomed slot  145  that engages rotatable cap tooth  136  of rotatable cap  133  to retain rotatable cap  133  on electrically conductive case end  6 . When rotatable cap  133  is rotated about its longitudinal axis by about 30° to 90°, rotatable cap tooth  136  is rotatably moved out of flat-bottomed slot  145 , thereby allowing rotatable cap  133  to be removed. These elements are shown in the perspective views of  FIGS. 39 and 40 , the angled flat  150  is indicated to facilitate placement of rotatable cap  133  onto electrically conductive case end  6  in order to engage rotatable cap tooth  136  with flat-bottomed slot  145 . 
   A cross-sectional view, through flat-bottomed slot  145  and perpendicular to the longitudinal axis, is presented in  FIGS. 41 and 42 . The view of  FIG. 41  indicates the position when rotatable cap  133  is in position to engage rotatable cap tooth  136  with flat-bottomed slot  145 . The view of  FIG. 42  indicates the same cross-sectional view as in  FIG. 41  but rotatable cap  133  has been rotated 90° from the position illustrated in  FIG. 41  to disengage rotatable cap tooth  136  from flat-bottomed slot  145  thereby allowing removal of rotatable cap  133 . 
   These various embodiments are of devices and methods for connecting an electrically conductive wire to a miniature, implantable stimulator in order to efficiently transmit or receive an electrical signal that is associated with the implantable stimulator. 
   Obviously, these methods of attaching a wire to a miniature implantable stimulator can be used in permutations and combinations not specifically discussed herein. Many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Technology Classification (CPC): 7