Abstract:
A connector and method of making electrical connection between an electrical conductor and a removable electrical device. The connector is an elastic material, such as silicone, that is both compatible with the environment and is an electrical insulator. It forces contact between the electrical device and integral contacts in the connector by virtue of its elasticity. The electrodes and the connections are protected from the environment to avoid electrical leakage or corrosion of the electrodes.

Description:
FIELD OF THE INVENTION 
     This invention relates to a connector for electrical devices and methods, and more particularly to connecting electrical wires to an implantable device to enable ease of connection and to minimize risk to the living tissue during and after surgery. 
     BACKGROUND OF THE INVENTION 
     Connection of electrical devices to electrical conductors is a common event, such as placing a fuse in a fuse holder. However, it is often desired to connect an electrical device in a hostile environment, such as in salt water or in living tissue. Such connections are particularly difficult to make with implantable devices in a human body, for example. 
     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 in U.S. Pat. Nos. 6,164,284, 6,185,452, and 6,208,894. 
     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 is 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. 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 DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a view of the implantable stimulator in cross section showing the connector. 
     FIG. 2 schematically depicts a cross-sectional view of the stimulator showing the connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 provides a cross-sectional view of a preferred embodiment of a hollow boot connector  1 . The connector is comprised of an elastic casing  16 , preferably silicone or another material that is chosen to be compatible with the design environment. Silicone is biocompatible and a preferred selection for applications involving implantation in living tissue. Further, the selected material is preferably an electrical insulator that minimizes leakage of electric current and that isolates the electrical device  2  from the environment. 
     The elastic casing  16  contains at least one insertion opening  18  that provides access through the wall of the casing  16  and into the inside of the hollow boot connector  1 , where the electrical device  2  is removably inserted. It is known to the inventors and within the scope of the instant invention, but not illustrated herein, that a plurality of openings  18  may be present in elastic casing  16  such that there are, in essence, a plurality of bands or straps formed by the plurality of openings  18 . The electrical device  2  may either be inserted before being placed into service, or during enablement for service, or as a replacement for a prior device during actual service. The connector  1  enables positive and rapid insertion of the electrical device  2  under difficult conditions, such as in seawater or in living tissue during surgery. 
     It is understood that the electrical device  2  encompasses electronic devices, electrical circuit components, conductors, sensors, and stimulators, such as, but not limited to the BION of Advanced Bionics Corporation. 
     The hollow boot connector  1  is further comprised of at least one electrical contact  10  that is integrally connected to an electrical conductor  7 , which is preferably a wire conductor  8  surrounded by a wire insulator  9 . The conductor  7  is preferably connected to the first electrical contact  10  by a known technique, such as crimping, as shown by crimping connection  14 . As alternative embodiments, any of the known methods of forming a connection between a wire and a contact is applicable in lieu of crimping, as is known in the art. 
     The elastic casing  16  preferably fits the electrical device  2  snugly such that when the electrical device  2  is inside the hollow boot connector  1 , the first electrical contact  10  is urged toward the first electrode  4  that forms part of electrical device  2  by the stretched elastic casing  16 . The first electrical contact  10  preferably has a nipple contact  20  that concentrates the contact stress between contact  10  and electrode  4 , thus insuring electric continuity. 
     Illustrated in FIG. 1 is a two-conductor connector  1 , having a first end  22  with a first conductor  7  and a second end  24  having a second conductor  11  each attached to the first electrical contact  10  at the first end  22  and the second electrical contact  13  at the second end  24 . In this configuration the elastic casing  16  is stretched when the electrical device  2  is inserted inside the hollow boot connector  1 , which in turn urges the respective electrical contacts against the first electrode  4  and the second electrode  6 . 
     It is preferred that the first conductor  7  be integrally bonded to the elastic casing at the first end  22  to assure that there is no leakage or failure at the first end  22  which might reduce or eliminate electrical conductivity between the first electrode  4  and the first electrical contact  10 . The wire insulator  9  is preferably glued to the casing  16 , although it may be thermally bonded for equal effect. It will be obvious to one skilled in the art that a similar bond may be utilized at second end  24 . 
     To insure electrical isolation between electrodes, insertion opening  18  is positioned so that it does not expose first electrode  4  or second electrode  6  of electrical device  2  to the environment surrounding the connector  1 . Further, to insure electrical isolation between electrodes, at least one sealing ridge  26  may be added, in an alternative embodiment, to the inside of elastic casing  16 . The sealing ridge  26  is located between insertion opening  18  and either the first electrode  4  or second electrode  6 . Obviously, multiple sealing ridges may be added to facilitate an effective seal. A further embodiment adds a seal receiver  28  to electrical device  2 , which mates with sealing ridge  26  to enhance the sealing effectiveness. Further, a tie, not illustrated may be placed around the outside of the elastic casing  16  either in lieu of the sealing ridge  26  or in conjunction with it, to assure a tight seal. 
     Illustrated in FIG. 2 is a hollow boot connector  31  having a first end  55  and a single first conductor  46  that is comprised of a wire conductor  48  with wire insulator  49 . Analogous to that described previously, the elastic casing  53  has an insertion opening  38  to accept the electrical device  32  to the interior of connector  31 . When the electrical device  32  is inserted therein, the elastic casing  53  is stretched such that the electrical contact  40  and its nipple contact  50  are urged into electrical contact with first electrode  34 . 
     Analogous to the embodiment previously presented, first conductor  46  is attached to electrical contact  40  by techniques know to one skilled in the art, preferably by crimping at crimp connector  44 . 
     In alternative embodiments, one or more sealing ridge  66  may be employed, optionally with a matching seal receiver  68  in the electrical device  32  surface to form a tight seal. Ties or compression bands (not illustrated) may be placed on the outside of connector  31  to facilitate the seal. 
     In this embodiment, the electrical device  32  has a second electrode  36  that is further comprised of an electrode extension  52 . At least a portion of electrode extension  52  protrudes from the second end  56  of connector  31  through an aperture  54  in the elastic casing  53 . It is obvious that there are many electrical devices and many electrode configurations available and which may be utilized with the hollow boot connector  31 . The presented embodiments are not limiting, but are illustrative of connector  31  applications. 
     Obviously, 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.