Abstract:
The invention is a methods of connecting wire that is suitable to connect electrical devices implanted in a living body. The invention enables manipulation of a narrow wire and a crimping component that are on the order of a millimeter in size. The method utilizes a crimper having a slideably attached connector holder that moves relative to the crimper to position an open end of the crimp connector between the crimp die and the crimp anvil, and a slideably attached wire holder that allows the wire holder to be moved relative to the crimper to position a portion of the wire within the open end of the crimp connector. Small components are positioned with precision using a combination of the user&#39;s senses, not necessarily including vision. The method does not require stripping electrical insulation from the wires and is also useful for interconnection of miniaturized non-medical electrical devices.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates in general to joining of electrical conductors and more specifically to devices and methods for connecting medical wires. 
   Medical wires, also sometimes referred to as biomedical wires and leads, provide electrical paths between different locations within a host. Medical wires are typically very thin, insulated wires formed of materials that are compatible with biological substances and which can be implanted into a host to provide electrical connections between medical devices, connectors, electrodes and other wires. Techniques include implanting medical devices such as, for example, sensors and stimulators into living tissue. These medical devices are often connected to an electrode through a medical wire that allows electrical energy to travel between the implanted medical device and the electrode. Such an arrangement is useful in situations where the medical device can not be implanted at the sensing or stimulation target area of the tissue due to size or other limitations. Other medical techniques also require the use of insulated electrical conductors such as medical wires and surgical wires to mechanically and electrically connect devices, connectors and other wires. 
   Conventional techniques for connecting medical wires are significantly limited. For example, wire connection techniques that include welding are less than optimum due to the limited types of materials that can be welded and convenience issues. All implanted materials must provide long-term compatibility with the host such that tissue inflammation, cellular alteration, and other adverse reactions are avoided or minimized. In addition, the materials should not be susceptible to damage or deterioration due to chemicals, electrolytes and other substances present in the host. Many biologically compatible materials can not be welded to other biologically compatible materials. For example, titanium and titanium alloys can not be welded to platinum, iridium or alloys of platinum and iridium. In addition, the use of welding equipment is often inconvenient and impractical. Welding at a surgery location, for example, can not be easily facilitated. 
   Other techniques for connecting medical wires include crimping connectors to the medical wire or device. Such connectors may include metal sleeves or tubes that are crimped around the conductor of a medical wire. Many conventional crimping techniques, however, are limited in that the insulation on the medical wire must be stripped before crimping. The insulation is difficult to remove. Further, insulation particles may irritate healing tissue and cause other adverse effects if the wire is stripped at the surgical site. Most methods of removing insulation cause changes in the chemical composition of the insulation resulting in the creation of pyrogens or toxic byproducts. Other crimping techniques are further limited by the awkward crimping tools that are difficult to use with the small and delicate medical wires, connectors and devices that require precision assembly to form a reliable and sturdy connection. 
   Accordingly, there is need for device and a method for easily, efficiently, and conveniently connecting medical wires that result in reliable electrical connections. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a block diagram of a top view of a connector holder and a wire holder connected to a crimping assembly in accordance with an exemplary embodiment of the invention. 
       FIG. 2  is an illustration of a perspective view of the crimping device in a closed position in accordance with the exemplary embodiment of the invention. 
       FIG. 3  is an illustration of an expanded perspective view of the crimping device  10  in accordance with the exemplary embodiment of the invention. 
       FIG. 4  is an illustration of a side view of the exemplary crimping device in the closed position. 
       FIG. 5  is an illustration of a portion side view of the exemplary crimping device  10  in the open position. 
       FIG. 6  is an illustration of a perspective view of a medical wire where the medical wire is a monofilar implantable lead. 
       FIG. 7  is an illustration of a perspective view of a medical wire where the medical wire is a Peterson lead. 
       FIG. 8  is an illustration of a partial plan view of the medical wire of  FIG. 6 . 
       FIG. 9  is an illustration of a perspective view of a crimp connector in accordance with the exemplary embodiment of the invention. 
       FIG. 10  is an illustration of a top view of the exemplary crimping device in the closed position. 
       FIGS. 11 through 16  are illustrations of top views of a portion of the exemplary crimping device during the crimping process. 
       FIGS. 17 through 20  are illustrations of a sequence of side elevation portion views of the wire holder during an exemplary process of inserting the medical wire into the wire holder. 
       FIGS. 21 through 24  are illustrations of a sequence of side elevation portion views of the connector holder during an exemplary sequence of inserting the crimp connector into the connector holder. 
       FIG. 25  is an illustration of a side elevation portion view of crimp die closed on the anvil with the wire holder omitted for clarity. 
       FIGS. 26 ,  27 , and  28  are illustrations of a sequence of side elevation portion views of the crimp die and the crimp anvil during the crimping process. 
       FIG. 29  is an illustration of a perspective portion view of a crimp connector crimped to a medical wire where the medical wire is a monofilar implantable lead. 
       FIG. 30  is an illustration of a perspective portion view of a completed splice of two medical wires where the monofilar implantable lead is connected to a second monofilar implantable lead by a crimp connector. 
       FIG. 31  is an illustration of a perspective portion view of the crimp anvil in accordance with the exemplary embodiment of the invention. 
       FIG. 32  is an illustration of a perspective portion view of the crimp die in accordance with the exemplary embodiment of the invention. 
       FIG. 33  is an illustration of an end elevation view of the crimping device with the holders in the closed position in accordance with the exemplary embodiment of the invention. 
       FIG. 34  is an illustration of an end elevation view of the crimping device with the holders in the open position in accordance with the exemplary embodiment of the invention. 
       FIG. 35  is a perspective view of medical device assembly suitable for use with the exemplary embodiment of the invention. 
       FIG. 36  is an illustration of a front view of a crimping device in accordance with second exemplary embodiment of the invention. 
       FIG. 37  is an illustration of a top view of the crimping device in accordance with the second exemplary embodiment showing the medical device holder attached to the crimping device. 
       FIG. 38  is an illustration of a top view of the crimping device in accordance with the second exemplary embodiment showing the medical device holder unattached to the crimping device. 
       FIG. 39  is a perspective view of a completed crimp connection (splice) after crimping by a crimping device in accordance with the exemplary embodiment of the invention. 
       FIG. 40  is a flow chart of a method of connecting a medical wire in accordance with the exemplary embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In accordance with an exemplary embodiment of the invention, a crimping device facilitates the connection of a crimp connector to a wire by holding the crimp connector and wire in a preferred relative position within a crimping assembly. A connector holder and a wire holder maintain the position of an end of the wire within an open end of the crimp connector while the operator activates the crimping device to squeeze the open end of the crimp connector between a crimp die and crimp anvil of the crimping assembly. A portion of the crimp connector is forced through the insulation of the wire to make an electrical connection. The crimping device can be used at a surgical site by a single operator to easily make reliable connections to wires such as medical wires without the use of awkward welding equipment and while minimizing complications due to insulation debris. In a second exemplary embodiment, a device holder holds a medical device to further facilitate the crimping process when the crimp connector is attached to the medical device. The exemplary crimping device discussed below, therefore, facilitates an efficient and accurate method of crimping small connectors to delicate insulated wires such as medical wires. In some circumstances, the dimensions and arrangements of the crimping device components may be modified to accommodate other types of wires and connectors. 
     FIG. 1  is a block diagram of a top view of a connector holder  40  and a wire holder  30  connected to a crimping assembly  6  in accordance with an exemplary embodiment of the invention.  FIG. 1  includes various blocks that represent components, regions, and areas of the crimping device  10  in an illustrated arrangement that indicates some of the relative sizes and positions of the represented components, regions and areas. The blocks and components illustrated in  FIG. 1 , however, are not necessarily to scale and do not necessarily represent all of the relative sizes, positions and shapes of the components or regions of the crimping device  10 . 
   In the exemplary embodiment of the invention, a crimp connector  100  is connected to a medical wire  110  by crimping the crimp connector  100  such as metal sleeve or tube to the insulated medical wire  110  using a crimper assembly  6  while the crimp connector  100  is held by a connector holder  40  connected to the crimper assembly  6 . A wire holder  30  holds the medical wire  110  while the relative positions of the connector holder  40  and the wire holder  30  are changed to position an end of the medical wire  110  within an open end of the crimp connector  100 . The crimp connector  100  is positioned between a crimp die  74  and a crimp anvil  20  of the crimper assembly  6 . In the exemplary embodiment, the crimp die  74  is formed on a crimp lever  72  and the crimp anvil  20  is formed on an anvil boss  18 . The crimp lever  74  rotates about a pivot to align the crimp die  74  with the crimp anvil  20  when the crimp lever  72  and the anvil boss  18  are squeezed together. As the crimp connector  100  is squeezed between the crimp die  74  and the crimp anvil  20 , the crimp die  74  forces a portion of the crimp connector  100  through the insulation of the medical wire  110  to form an electrical connection between the crimp connector  100  and the conductor of the medical wire  110 . 
   In the exemplary embodiment, both the connector holder  40  and the wire holder  30  are slideably attached to the crimper assembly  6  allowing both holders  30 ,  40  to move toward each other. The crimping device  10  includes a base  12  in the exemplary embodiment that facilitates the connection of the crimper assembly  6  to the connector holder  40  and the wire holder  30 . Other techniques, however, may be used to attach the connector holder  40  and the wire holder  30  to the crimping assembly  6  in some circumstances. As explained below in further detail, the operator places the medical wire  110  in the wire holder  30  such that an end of the medical wire  110  extends past the edge of wire holder  30 . The crimp connector  100  is placed in the connector holder  40  such that the open end of the crimp connector  110  extends past the edge of the connector holder  40 . The connector holder  40  and the wire holder  30  are moved toward each other to position the end of the medical wire  110  within the open end of the crimp connector  100 . When the holders  30 ,  40  are in the closed position, the open end of the crimp connector  100  is positioned between the crimp lever  72  and the crimp anvil  20 . The crimp connector  100  and the medical wire  110  are shown as dashed-line boxes to illustrate that the crimp connector  100  and the medical wire  110  are inserted and removed during operation and are not part of the crimping device  10 . In the exemplary embodiment, the edge of the crimp connector  100  and the end of the medical wire  110  abut the edges of the anvil boss  18  before the holders  30 ,  40  are moved toward each other to insert the medical wire  110  within the crimp connector  100 . 
   Although the connector holder  40  may include any of several configurations and mechanisms for holding the crimp connector  100 , the crimp connector  100  is held within a tube-and-lead groove  48  of the connector holder  40  in the exemplary embodiment. As discussed below, a connector retainer (not shown) further secures the crimp connector  100  within the groove  48 . The connector holder  40  includes a lead holder  39  to hold a lead connected to the crimp connector  100  in some circumstances. The lead holder  39  may be useful where a biomedical device is connected to the crimp connector  100  by a section of medical wire (lead). Further, the medical wire (lead) that is connected to the crimp connector  100  may be any type of suitable wire, medical wire or biomedical wire that may be implanted in a host, connected to other devices or connectors or may include only a section of wire. Those skilled in the art will recognize that the lead may be referred to as a lead, wire, medical wire, extension wire, connection wire or by other terms. 
   The wire holder  30  includes any of several configurations and mechanisms for holding the medical wire  110 . In the exemplary embodiment, the wire holder  30  includes a wire groove  38  for holding the medical wire  110 . A wire retainer (not shown) further secures the medical wire  110  in the exemplary embodiment. 
     FIG. 2  is an illustration of a perspective view of the crimping device  10  in a closed position in accordance with the exemplary embodiment of the invention. The exemplary crimping device  10  may be constructed using a variety of techniques, components and arrangements. As described above, the crimping device  10  includes a crimp die  74  on a crimp lever  72  and a crimp anvil  20  on an anvil boss  18  in the exemplary embodiment. The anvil boss  18  is attached to the base  12  that is hingeably attached to the crimp lever  72  by a pin  54  to form a pliers-type assembly facilitating use of the crimping device  10  as a hand tool. The crimper assembly  6  ( FIG. 1 ) is located within a crimping area  66 . A protected storage area  86  is formed between the base  12  and the lever  72 . 
     FIG. 3  is an illustration of an expanded perspective view of the crimping device  10  in accordance with the exemplary embodiment of the invention. The crimp lever  72  comprises a bore  34  for receiving the pin  54  and adjacent side broad surfaces to fit within the slot between a wire boss  14  and a connector boss  16  of the base  12 . A paddle  76  is welded to the lever  72  where the paddle  76  includes a force limiter  78  that limits the minimum distance between the paddle and the base  12 . In addition to the anvil boss  18  and the crimp anvil  20 , the base  12  includes gripping aids  24  formed by removing a portion of the base  12 . Both the wire boss  14  and the connector boss  16  have coaxial bores  34  for receiving a pin  54 . The pin  54  is affixed in bores  34  of the bosses by setscrews  58 . Each end of the pin  54  has a semi-toroidal groove  56  to accept a split retaining ring  52  made of round stainless steel wire. In some circumstances, a lanced pin (not shown) is pressed only into the bores  34  of wire boss  14  and connector boss  16  allowing the setscrews  58  to be eliminated while other components are free to move on the pin  54 . 
   The wire holder  30  in the exemplary embodiment is slideably affixed by the bore  34  on pin  54 . The travel of the wire holder  30  is bounded by the broad face of the wire boss  14  in the inward direction (toward the connector holder  40 ) and by a retaining ring  52  in the outward direction (away from the connector holder  40 ). In some circumstances, the bore  34  and the pin  54  are lubricated with a suitable lubricants such as Krytox® perfluorinated grease (Krytox is a registered trademark of E. I. DuPont De Nemours and Company Corporation). The wire holder  30  includes a protruding finger tab  36  to aid in positioning the wire holder  30  in the exemplary embodiment. A mortise  32  in the wire holder  30  is configured to receive the wire retainer  60 . The flexible wire retainer  60 , semi-cylindrical medical wire groove  38 , and a ramp  50  facilitate insertion of the medical wire  110  as discussed below in further detail. The wire retainer  60  is made from rubber in the exemplary embodiment and includes a tenon  64  to fit the mortise  32 , a detent  62 , and a nose  68  to secure the medical wire  110 . 
   The connector holder  40  is slideably affixed by bore  34  on pin  54 . The travel of the connector holder  40  is bounded by the broad face of the connector boss  16  in the inward direction (toward the wire holder  30 ), and by retaining ring  52  in the outward direction (away from the wire holder  30 ). In some circumstances, the bore  34  and the pin  54  are lubricated with a suitable lubricant such as Krytox perfluorinated grease. The connector holder  40  includes a protruding pull tab  46  in the exemplary embodiment to aid in positioning the connector holder  40 . The connector holder includes a mortise  42  configured to receive the connector retainer  70 . The connector retainer  70 , a semi-cylindrical tube-and-lead groove  48 , and a ramp  50  facilitate insertion of the crimp connector  100  as described in further detail below. The connector retainer  70  has a tenon  64  to fit mortise  42 , a detent  62  (not visible), and a nose  68  to secure the crimp connector  100 . 
   In the exemplary embodiment, the base  12 , the lever  72 , the pin  54 , and the retaining rings  52  are made of corrosion resistant metal or alloy such as 17-4 PH stainless steel. The wire holder  30  and the connector holder  40  are made of machined or molded polymer such as polyarylethersulfone. The wire retainer  60  and the connector retainer  70  are made of hydrolysis- and depolymerization-resistant elastomer, such as silicone rubber. An example of a suitable hardness of the retainers  60 ,  70  is approximately 79 on the Shore A scale. 
     FIG. 4  is an illustration of a side view of the exemplary crimping device  10  in the closed position. In the closed position, a gap  88  remains between the force limiter  78  and the base  12 , where the gap  88  allows over-travel and tactile feedback during crimping. The protected storage area  86  is indicated by dashed lines. 
     FIG. 5  is an illustration of a portion side view of the exemplary crimping device  10  in the open position. In the open position, the crimp lever  72  is rotated in direction  80  about the pin  54  in order to provide the greatest possible access to the crimping area  66  and holders  30 ,  40 . Further rotation of the lever  72  is stopped by contact between the end of the lever  72  and the slot in base  12  (not visible). Any pinching during the opening process is prevented by a protruding portion  82  of lever  72 . The open position also provides access for inspecting the crimping die  74  and any items in the storage area  86 . 
   The medical wire  110  may include any of several types of medical wires, leads or other conductors. In the exemplary embodiment, the medical wire  110  is any of several types of medical wires  110  having conductors covered by insulation and that may be implanted into living tissue.  FIG. 6  and  FIG. 7  include illustrations of examples of medical wires  110  suitable for use with the exemplary embodiment of the invention. Other medical wires  110  and leads may be used in some circumstances. 
     FIG. 6  is an illustration of a perspective view of a medical wire  110  where the medical wire  110  is a monofilar implantable lead  92 . The monofilar implantable lead  92  includes stranded metal conductors  94  (shown stripped only for clarity) that are sheathed in a perfluorinated polymer electrical insulation. Often referred to as a Shimada lead, the monofilar implantable lead  92  includes a coil that is 0.51 mm in diameter and has 28 coils per cm. The stranded metal conductors  94  are wires having a diameter of 44 μm, made of 316L (low carbon) stainless steel. 
     FIG. 7  is an illustration of a perspective view of a medical wire  110  where the medical wire  110  is a Peterson lead  96 . The exemplary Peterson lead  96  has a diameter of 0.61 mm and bifilar windings of 30 coils per cm. The conductors  98  (shown stripped only for clarity) are wires having a diameter of 44 μm, made of 316L (low carbon) stainless steel. The conductors  98  are arranged in two nested groups with opposite slow twist. The wire bundle is encapsulated in a transparent, perfluorinated polymer. A core  90  of high strength polymer monofilament runs the entire length of the lead to insure stability. 
     FIG. 8  is an illustration of a partial plan view of the medical wire  110  of  FIG. 6 . In  FIG. 8 , the stranded metal conductors  94  are outlined by dashed lines as they follow a helical path, the coarse dash indicate portions lying below the center plane, and the fine dashed lines define those portions above the center plane. When the monofilar implantable lead  92  ( 110 ) is crimped (into the plane of  FIG. 8 ) there are crossing areas  104  in which the over and under portions of the stranded metal conductors  94  overlap and cross. During crimping, the stranded metal conductors  94  become thinner and wider until overlapping and crossing areas  104  constitute the preponderance of the area within the footprint of the crimp. The overlapping and crossing character of coiled leads is discussed in further detail below with discussion of the crimping process. 
     FIG. 9  is an illustration of a perspective view of a crimp connector  100  in accordance with the exemplary embodiment of the invention. The crimp connector  100  may have any of several configurations, shapes and sizes. An example of a suitable crimp connector  100  is a barrel type connector formed by cutting a segment of drawn seamless metal tubing. Suitable crimp connectors  100  for use with Shimada and Peterson medical wires are made of 316L stainless steel to insure electrochemical compatibility. The exemplary crimp connector  100  has a diameter of approximately 1.0 mm and a bore slightly larger than the medical wires  110  to be crimped. End edges  106  are rounded to protect the medical wire  110  and any covering applied to the crimp connector  100  after crimping. In the exemplar embodiment, the inner edges are rounded to facilitate inserting the ends of the medical wire  110 . Two crimp zones  102  are indicated by circumferential dashed lines in  FIG. 9 . The exemplary crimp connector  100  is symmetric about its axis to simplify handling and positioning. 
     FIG. 10  is an illustration of a top view of the exemplary crimping device  10  in the closed position. In the closed position, the crimp lever  72  is closed on the base  12 , the wire holder  30  is closed so that wire groove  38  abuts the anvil boss  18 , and the connector holder  40  is closed so that the tube-and-lead groove  48  abuts the anvil boss  18 . 
     FIGS. 11 through 16  are illustrations of top views of a portion of the exemplary crimping device  10  during the crimping process.  FIG. 11  is an illustration of a top view of the crimping device  10  as the crimping device  10  is opened from a closed position to the open position. The crimping device  10  is opened by rotating the crimp lever  72  in the direction of the arrow. 
     FIG. 12  is an illustration of a top view of the crimping device  10  as the wire holder  30  and the connector holder  40  are opened. The wire holder  30  and connector holder  40  are moved in an outward direction as indicated by straight arrows. The crimp connector  100  is placed in the tube-and-lead groove  48  and the medical wire  110  is placed in the wire groove  38  to secure the crimp connector  100  and the medical wire  110  within the holders  30 ,  40 . 
     FIG. 13  is an illustration of a top view of the crimping device  10  with the crimp connector  100  and the medical wire  110  secured in the connector holder  40  and the wire holder  30 , respectively. The crimp connector  100  and medical wire  110  are held in the predetermined axial locations by the respective connector retainer  70  and the wire retainer  60  as discussed in further detail below. The edge of the crimp connector  100  abuts the anvil boss  18 . The axial location of the crimp connector  100  is determined in part by the position of the connector holder  40  and in part by the edge of the wire groove  38 . The axial location of the medical wire  110  is determined in part by the position of the wire holder  30  and by observing that the end of the medical wire  110  abuts the anvil boss  18  during insertion of the medical wire  110 . The lateral positions of all parts are predetermined and controlled by the locations of the base  12 , the pin  54 , and the grooves  38 ,  48  relative to the nominal center of the crimper assembly  6 . 
     FIG. 14  is an illustration of a top view of the crimping device  10  as the connector holder  40  is moved from the open position to the closed position. The connector holder  40  is moved inward, as indicated by the arrow, until the inner half of the crimp connector  100  is accurately positioned over the crimp anvil  20 . 
     FIG. 15  is an illustration of a top view of the crimping device  10  as the wire holder  30  is moved from the open position to the closed position. The wire holder  30  is moved inward as indicated by the arrow in order to slip the end of the medical wire  110  into the open end of the crimp connector  100 . As the wire holder  30  is fully closed, the end of the medical wire  110  is positioned just short of the center plane of the crimp connector  100 . In the exemplary embodiment, a medical wire  110  or lead resides in each half of the crimp connector  100  in a completed crimp connection. Accordingly, predetermined axial repositioning of leads precludes a faulty crimp by dint of under-insertion, and precludes an impossible or faulty splice due to over-insertion. The crimp lever  72  is closed and the paddle pressed toward the base  12  until gap  88  between force limiter  78  and base  12  vanishes, and contact is felt by the operator. The gap  88  allows for over-travel and tactile feedback; whereas the abutting surfaces of the lever  72  and the anvil boss  18  control the actual crimping force. 
     FIG. 16  is an illustration of a top view of the exemplary crimping device  10  in the open position and completed crimped assembly released from the crimping device  10 . The crimped assembly includes the crimp connector  100 , the medical wire  110  and, in some circumstances, a biomedical device. The crimped assembly is released by applying a downward fingertip pressure to the retainers  60 ,  70  and gently wiggling the medical wire  110  in order to release it without applying undesirable tension to the lead. 
     FIG. 17  through  FIG. 20  are illustrations of a sequence of side elevation portion views of the wire holder  30  during an exemplary process of inserting the medical wire  110  into the wire holder  30 . In the exemplary embodiment of the invention, a ramp  49  of the wire holder  30 , in combination with the top surface of the wire retainer  60 , forms a shallow valley configured to fit the fingertip  108  of a surgeon or other crimp device operator. 
     FIG. 17  is an illustration of a side elevation portion view of the wire holder  30  as the operator slides the medical wire  110  down the ramp  49 . The operator slides and rotates a fingertip  108  in the direction of the arrow while pressing the medical wire  110  against the ramp  49  to move the medical wire  110  down the ramp  50 . In most circumstances, the surgeon will feel, but not see, medical wire  110  slide down the ramp  49 . 
     FIG. 18  is an illustration of a side elevation portion view of the wire holder  30  as the operator presses the medical wire  110  into the wire groove  38 . The operator uses the fingertip  108  to press the medical wire  110  in the direction of the arrow while placing increasing pressure on the top surface of wire retainer  60 . The operator, in most situations, will not see the medical wire  110  come in contact with the nose  68  of the wire retainer  60 . In most circumstances, the operator will feel, and possibly hear, the medical wire  110  come in contact with the nose  68  of the wire retainer  60 . The wire groove  38  is partially closed by the nose of the wire retainer  60 . 
     FIG. 19  is an illustration of a side elevation view of the wire holder  30  as the operator continues to press the medical wire  110  into the wire groove  38 . The fingertip  108  is continually rolled in the direction of the curved arrow while simultaneously and progressively increasing the downward pressure (straight arrow) on the wire retainer  60  until the wire retainer  60  deforms enough to move the nose  68  away from the wire groove  38  to admit the medical wire  110  into the wire groove  38  of wire holder  30 . In most circumstances, the operator will feel and hear, but not see, the snap of the medical wire into the wire groove  38 . 
     FIG. 20  is an illustration of a side elevation view of the wire holder  30  where the medical wire  110  is secured in the wire groove  38  by the wire retainer  60 . After the fingertip  108  is rolled to the left to remove some of the downward pressure on the wire retainer  60 , the nose  68  of the wire retainer  60  firmly axially restrains the medical wire  110  in the wire groove  38 . The operator visually determines that the end of the medical wire  110  abuts the face of the anvil boss  18 . If the end of the medical wire  110  is not in the abutting position, the medical wire  110  is adjusted using the fingertip  108 . In most circumstances, some squirming of the fingertip  108  will move the medical wire  110  to the desired position. 
     FIGS. 21 through 24  are illustrations of a sequence of side elevation portion views of the connector holder  40  during an exemplary sequence of inserting the crimp connector  100  into the connector holder  40 . A ramp  50  of the connector holder  40 , in combination with the top surface of connector retainer  70 , forms a shallow valley configured to fit the gloved fingertip  108  of the surgeon. 
     FIG. 21  is an illustration of a side elevation portion view of the connector holder  40  as the operator slides the crimp connector  100  into the groove  48 . The surgeon presses crimp connector  100  against ramp  50  while sliding and rotating a gloved finger  108  in the direction of the arrow. The surgeon will feel the sliding of the crimp connector  100  in most circumstances. 
     FIG. 22  is an illustration of a side elevation portion view of the connector holder  40  as the operator presses the crimp connector  100  into the tube-and-lead groove  48 . The fingertip  108  presses the crimp connector  100  in the direction of the arrow while placing increasing pressure on the top surface of connector retainer  70 . In most circumstances, the operator will feel and possibly hear the crimp connector  100  come in contact with the nose  68  of connector retainer  70 . The groove  48  is partially closed by the nose  68  of the connector retainer  70 . 
     FIG. 23  is an illustration of a side elevation portion view of the connector holder  40  as the fingertip  108  further guides the crimp connector  100  into the tube-and-lead groove  48 . The fingertip  108  continually rolls in the direction of the curved arrow while simultaneously and progressively increasing the downward pressure (straight arrow) on the connector retainer  70  until it deforms enough to admit the crimp connector  100  into the groove  48 . The surgeon will feel and hear the snap of the crimp connector  100  into the groove  48  in most circumstances. 
     FIG. 24  is an illustration of a side elevation portion view of the connector holder  40  where the crimp connector  100  is secured in the groove  48  by the connector retainer  70 . The fingertip is rolled to the left to remove the downward pressure on the connector retainer  70  such that the nose  68  of the connector retainer  70  firmly retains the crimp connector  100  in the groove  48 . The operator visually inspects the crimp connector  100  to verify that the inner end (open end) of the crimp connector  100  abuts the face of the anvil boss  18  and that the outer end of the tube is fully seated in the end of the groove  48 . 
     FIG. 25  is an illustration of a side elevation portion view of crimping die  74  closed on the anvil  20  with the wire holder  30  removed for clarity. In the exemplary embodiment, the anvil  20  has a penetrator  112  that facilitates the crimping process as described below in further detail. The side walls of the anvil cavity diverge from the center plane to reduce wedging of the crimped connector  100  and allow the crimp connector  100  to be released without applying unwanted tension to the medical wire  110 . As illustrated in  FIG. 25 , the wire groove  38  is coaxial with the tube-and-lead groove  48  in the exemplary embodiment. The lateral positions of the crimp connector  100  and medical wire  110  are determined by the relative locations of the wire holder  30  and connector holder  40  and their respective grooves  38 ,  48 . The wire holder  30  and connector holder  40  slide on the pin  54  but are restricted from rotating about the axis of the pin  54  in order to provide precise spatial alignment of the medical wire  110  and the crimp connector  100  relative to the nominal center of the crimper assembly  6 . The inner planar face of the connector holder  40  slides along the proximate planar face of the connector boss  16  of the base  12  and the inner planar face of the wire holder  30  slides along the proximate planar face of the wire boss  14 , thereby constraining the holder motion to linear translation. In some circumstances, the sliding proximate faces of the wire holder  30  and connector holder  40  and the wire bosses  14  and connector boss  16  are lubricated with Krytox perfluorinated grease. 
     FIG. 26  through  FIG. 28  are illustrations of a sequence of side elevation portion views of the crimping die  74  and the anvil  20  during the crimping process. The medical wire  110  within the crimp connector  100  is squeezed between the crimping die  74  and the anvil  20  as the crimping die  74  is moved toward the anvil  20 . Although the exemplary crimping device  10  is a hand tool that is manually operated, the crimping device may include other mechanisms for forcing the crimping die  74  toward the anvil  20 . A pneumatic mechanism, for example, may be used to perform or to assist the operator in activating the crimper assembly  6  in some circumstances. 
     FIG. 26  is a side elevation portion view of the crimper assembly  6  as the crimping die  74  contacts the crimp connector  100 . The crimping die  74  begins a downward stroke in the direction of the arrow as the lever  72  is moved toward the base  12 . 
     FIG. 27  is a side elevation portion view of the crimper assembly  6  as the crimp connector  100  is deformed. The crimping die  74  is completing half of the downward crimping stroke and is flattening the top surface of crimp connector  100 . The penetrator  112  has begun to deform the bottom surface of the crimp connector  100  and the medical wire  110  is partly compressed. 
     FIG. 28  is a side elevation portion view of the crimper assembly  6  as the crimping die  74  has reached the maximum travel toward the anvil  20 . The bottom surface of the crimp lever  72  abuts the top surface of anvil  20 , thereby completing the crimping stroke. The penetrator  112  forms an axial rounded ridge of a predefined radius in the inner wall of the crimp connector  100 . The distance from the ridge crest to the ceiling of crimp connector  100  is configured to displace the electrical insulation of the medical wire  110  in order to bring the conductors in contact with each other and with the inner walls of crimp connector  100  to form an electrical and mechanical connection. During crimping, the stranded conductors are spread laterally and both the insulation and the portion of the crimp connector  100  in the crimping area  66  are displaced axially outward (stretched). Stripping the electrical insulation from the end of the medical wire  110  is not required, and would likely interfere with achieving an optimum final crimp geometry. In some circumstances, the medical wire  110  is crimped while wetted or flooded with uncured silicone elastomer in order to inhibit body electrolyte permeation. 
     FIG. 29  is an illustration of a perspective portion view of a crimp connector  100  crimped to a medical wire  110  where the medical wire  110  is a monofilar implantable lead  92 . The anvil crimp portion  122  of the crimp has an axial length  118  that is approximately equal to the diameter of the crimp connector  100  in the exemplary embodiment. The die crimp portion  120  of the crimp is located on the opposite (not visible) side of crimp connector  100 . The transition from the fully crimped area to the non-deformed portions of the crimp connector  100  is symmetric. 
     FIG. 30  is an illustration of a perspective portion view of a completed splice of two medical wires  110  where the monofilar implantable lead  92  is connected to a second monofilar implantable lead  93  by a crimp connector  100 . The crimp connector  100  has the anvil crimp portion  122  of the first crimp and a die crimp portion  120  of a second crimp having an axial length  119  approximately equal to the diameter of crimp connector  100 . The axial length  119  is equal to the axial length  118  in the exemplary embodiment. In some circumstances, the axial lengths  118 ,  119  may be different. Although the die crimp portion  120  and anvil crimp portion  122  may be collinear in some situations, they need not be collinear since the wire holder  30  and connector holder  40  do not direct the medical wires  110  and the crimp connector  100  in any particular orientation. Where the medical wires  110  are Peterson leads, the core of the Peterson lead is displaced along with the electrical insulation resulting in a similar crimp or splice as a Shimada lead. The core  90  is also mechanically anchored by the crimp where a Peterson lead is used. 
   In some circumstances, the second monofilar implantable lead  93  is connected to a biomedical device such as a sensor, a stimulation electrode, a signal detection electrode, or an electronic module. The lead  93  is integrally constructed with a biomedical device in some situations. 
     FIG. 31  is an illustration of a perspective portion view of the anvil  20  in accordance with the exemplary embodiment of the invention. The exemplary anvil  20  has a central crimp area  116  having an axial length  118  (relative to the crimp connector  100 ) that is approximately equal to the diameter of the crimp connector  100 . On either side of the central crimp area  116 , the topology of the anvil  20  is repeated, but angularly disposed to the central crimp area  116 . The angle is predetermined to provide a smooth transition from central crimp area  116  to the undeformed portions of the crimp connector  100  and to retain concavity symmetrically about the central crimp area  116 . An enlarged concavity (as opposed to an abrupt boundary of the central area) enhances the stored residual elastic energy that urges the crimp connector  100  inner walls toward the flattened conductive strands of the medical wire  110 . An example of a suitable method of fabricating the predetermined transition includes using wire electric discharge machining (WEDM) where cutting forms the basic shape of the anvil  20 . The base is rotated by the predetermined angle, and the anvil geometry (program) is retraced in order to bevel the edge of the otherwise abruptly truncated crimp area. The opposite edge of the crimp area is beveled using the negative of the predetermined angle. The WEDM is programmed to leave a central crimp area  116  having an axial length  118 . An example of a suitable crimp anvil bevel angle lies in the range of 8 to 18 degrees. 
     FIG. 32  is an illustration of a perspective portion view of the crimping die  74  in accordance with the exemplary embodiment of the invention. The exemplary crimping die  74  includes a central crimp portion  117  having an axial length  119 . Although in some situations the central crimp area  116  and central crimp portion  117  may be different, the central crimp portion  117  is equal to the central crimp area  116  of the anvil  20  in the exemplary embodiment. A suitable method of forming the crimping die  74  includes using a beveling process similar to the process discussed above with reference to the anvil  20 . An example of a suitable crimp die bevel angle lies in the range of 20 to 38 degrees. Tests of beveled crimps have determined that the bevel angle, in combination with the predetermined terminal distance between the crimping die  74  and the anvil  20 , may be configured such that the electrical connection in the central crimp portion  117  of the crimp has a minimum electrical resistance while maximizing the mechanical retention of the medical wire  110  within the crimp connector  100 . Tests have indicated that the mechanical retention due to the gripping of the medical wire  110  by the beveled portions of the crimp generally exceeds the strength of the medical wire  110 . During tension testing, for example, the medical wire  110  breaks outside the crimp area. Further, testing has shown that an instrument having a preferred crimp configuration achieves excellent electrical and mechanical connections of medical wires  110  having dimensions and properties lying in the range between those of the Shimada lead (small) and the Peterson lead (large). 
   In some circumstances, bevels with two or more retraces of the WEDM profile program may be formed where each retrace is performed at a different prescribed angle in order to contour the bevel. The junction of the contour with the straight portion of the crimping die  74  or anvil  20  is angular in some situations and tangential in others. 
     FIG. 33  is an illustration of an end elevation view of the crimping device  10  in the closed position in accordance with the exemplary embodiment of the invention. The detents  62  of wire retainer  60  and connector retainer  70  are compressed by interference contact with the upper surface of the base  12 . In some circumstances, the contacts are lubricated with Krytox perfluorinated grease to provide smooth sliding action. When the surgeon&#39;s fingertip  108  urges pull tab  46  in the direction of the arrow, the wire holder  30  and connector holder  40  slide smoothly to the open position as shown in  FIG. 34 . Just as a holder ( 30 ,  40 ) reaches the fully open position, the detent  62  begins to restore its uncompressed state. In the fully open position, the detent  62  retains a prescribed residual deformation that urges the contact between the detent  62  and the rounded shoulder  114  of the base  12  to keep the wire holder  30  and connector holder  40  in the fully open position in order to prevent inadvertent placement of the medical wire  110  or the crimp connector  100  in a less than optimum position. 
   Upon closing of the wire holder  30  and connector holder  40  tactile feedback informs the operator of the onset of closing by initially increasing resistance to sliding and indicating recompression of detents  62  in the exemplary embodiment. Visual, auditory, and tactile feedback further inform the operator that the closing strokes are completed and the wire holder  30  and connector holder  40  contact the respective proximate wire boss  14  and connector boss  16  of the base  12 . In most situations, the trained operator or surgeon will watch the end of the medical wire  110  as it successfully enters the open end of the crimp connector  100 . 
   After the initial portion of the holder ( 30 ,  40 ) closing stroke, recompression of the detents  62  urge an upward deformation of the retainers  60 ,  70  in order to increase the strength of their respective grips on the medical wire  110  and the crimp connector  100 , which further reduces any tendency to inadvertently slide to less than an optimum position in the respective grooves  38 ,  48 . 
   In some situations, the crimp connector  100  remains exposed when implanted. The crimp connector  100  forms an electrode in electrical contact with body tissue in order to stimulate a nerve or to detect nerve impulses. In some circumstances, an uncoated crimp connector  100  is coated with platinum or other substance known to achieve a more chemically inert and electrically less noisy contact. The interior of the crimp connector  100  may be protected with cured-in-place elastomer or other matter known to delay chemical attack by body electrolytes (wet crimping) as described above. 
   In a majority of applications, the desired function of the crimp is to extend the reach to electrical stimuli or detected signals at a location removed from the immediate vicinity of the crimped medical wire  110 . As discussed below with reference to  FIG. 39 , a suitable technique for minimizing interaction with human tissue includes covering the completed splice with a segment of medical grade silicone rubber tubing (silicon rubber boot). The sleeve, tube, boot or molding tubular sleeve is slipped on the medical wire  110  before the crimp is completed. After completing the crimp the sleeve is pulled over crimp connector  100  and the silicon tubing is back-filled with uncured but activated elastomer. The sleeve ends are closed using sutures. Some of these steps are modified or omitted in some circumstances, for example, the backfilling step and the use of sutures is omitted in some situations. In addition to providing mechanical strain relief during normal body flexing, a sleeve protects the splice from chemical attack and electrically insulates the splice from body tissue. A spliced medical wire  110  insulated as described above facilitates maximum electrical conduction to and from an intended site. 
   In the exemplary embodiment, the materials used for constructing the crimping device  10  include materials known to be biocompatible with living tissue since many of the applications of the crimping device includes crimping medical wires  110  and crimp connectors  100  that are intended to be implanted, or re-implanted in living tissue. For example, Krytox perfluorinated grease is assumed to be biocompatible. The Food and Drug Administration does not require testing of the biocompatibility of Krytox because its similarity to other tested perfluorinated materials implies complete chemical inertness. Krytox is stable when subjected to repeated steam sterilization (autoclaving). Whereas Krytox is used in the interior portions of the exemplary crimping device  10 , there is a remote possibility that the grease may be inadvertently transferred to implantable objects during surgery. 
   Further, Radel® R polyphenylsulfone (Radel is a registered trademark of Solvay S.A.) is a moldable plastic that has been successfully tested for biocompatibility in animals. Radel R resists hydrolysis, and retains dimensional stability after hundreds of autoclave cycles. 
   Stainless steel is notorious for galling when rubbed against itself, particularly when both parts are made of the same alloy. To prevent galling, modified tungsten disulfide powder is blasted onto at least one of the rubbing surfaces of stainless steel parts, then the excess powder is removed until further wiping removes no more material. Remnant tungsten disulfide is chemically bonded to the surface interstices of the stainless steel. The film strength of the lubricative treatment exceeds the strength of the stainless steel, resists hydrolysis, exposure to high temperature, and is stable when repeatedly sterilized in live steam. The application process is proprietary to Dicronite® Dry Lube, (Dicronite is a registered trademark of Lubrication Sciences, Inc.). Dicronite has been successfully tested for biocompatibility in animals. 
   Dicronite lubrication of surfaces sliding steel-on-steel may create microscopic particles of an alloy of stainless steel and tungsten disulfide, but these materials have successfully passed biocompatibility trials. In addition, subsequent lubrication with Krytox perfluorinated grease will entrap any microscopic particles, and the grease is known to be biomedically benign. Further, the configuration of the exemplary crimping device  10  minimizes the likelihood of the medical wire  110  or the crimp connector  100  from contacting the sliding surfaces. The anvil  20  and crimping die  74  surfaces that contact the crimp connector  100  are not treated with Dicronite in the exemplary embodiment. 
   An example of a suitable alloy for the metal portions of the exemplary crimping device  10  is 17-4 PH, which is known to resist corrosion in live steam (autoclaving), and may be hardened by heat treatment to approximately Rockwell 44 C in order to prolong the useful life of the crimping die  74  and the anvil  20 . The crimping die  74  and anvil  20  are zone hardened (local heat treatment) in some circumstances. Steel parts are thoroughly cleaned, and then passivated in hot citric acid solution in order to remove the last vestiges of “free iron” that are suspected of initiating corrosion. 
   The exemplary crimping device  10  and method substantially enhances the convenience and speed with which a connection can be made thereby enabling a surgeon to easily replace a faulty connection with a new splice, extend an old lead, or replace an implanted component by cutting out the old splice or lead, and re-splicing. The length of the splice is relatively short, and very little of the length of a lead (medical wire  110 ) is lost when a splice is excised, because the leads may be cut immediately at the crimp connector  100  end. 
     FIG. 35  is a perspective view of medical device assembly suitable for use with the exemplary embodiment of the invention. As discussed above, common uses for implantable medical devices include implanting a medical device  150  for stimulating or sensing living tissue. Examples of implantable medical devices  150  include the Bion® medical devices (Bion is a registered trademark of Advanced Bionics Corporation) which may be used as sensors or as stimulators. As described above, it is often advantageous to connect a medical wire  110  to the medical device  150  to provide an electrical path between a target site and a suitable location within the host to implant the medical device  150 . Typical implantation techniques often include connecting a medical device  150  to a medical wire  110  implanted in a host and subsequently implanting the medical device  150 . The medical device  150 , therefore, often is assembled as part of a medical device assembly that includes a short length of medical wire  154  that is terminated in a crimp connector  100 . The medical wire  154  and connector  100  are often referred to as a “pigtail”. The crimp connector  100  is connected to the implanted medical wire  110  at a sterile surgical site by the surgeon prior to implanting the medical device assembly. 
   The exemplary embodiment may be used with a variety of medical devices and medical devices  150  that are assembled in any of several ways. The exemplary medical device  150 , however, is assembled under controlled conditions prior to use at the surgical site. A stub connector includes a stub head  158  and stub shaft (not shown). The stub head  158  is laser welded to the medical device  150  and a crimp connector  156  such a tube is pressed onto the stub shaft. The medical wire  154  is connected by crimping the crimp connector  156  to the medical wire  154  using crush-penetration and forcing a portion of the crimp connector  156  through the insulation of the medical wire  154  to make an electrical connection between the crimp connector  156  and the conductor of the medical wire  154 . An example of a suitable material for the stub connector and crimp connector  156  is titanium alloy. The medical wires  110 ,  154  may include 316L stainless steel stranded wire insulated with PTFE insulation such as Teflon® (Teflon is a registered trademark of E. I. DuPont De Nemours and Company Corporation). The crimp connector  156  is crimped to the medical wire  110  by forming a crimp zone  102  such that the crimp zone  102  has a shape and dimensions adequate to accomplish crush-penetration through the insulation and make an electrical contact without damaging the inner stranded conductor of the medical wire  154 . Those skilled in the art will recognize that the medical wire  154  may be any type of suitable medical wire or biomedical wire and may be referred to in the industry as a wire, medical wire, biomedical wire, lead or pigtail. Further, the medical wire  110  that is connected to the crimp connector  100  may be any type of suitable wire, medical wire or biomedical wire and may be implanted in a host, connected to other devices or connectors or may include only a section of wire. Those skilled in the art will recognize that the medical wire  110  may be referred to as a lead, wire, medical wire, extension wire, connection wire or by other terms. 
     FIG. 36  is an illustration of a front view of a crimping device  160  in accordance with second exemplary embodiment of the invention. The crimping device  160  includes a medical device holder  162  for holding a medical device  150  while a medical wire  110  is crimped to the crimp connector  100  of the medical device assembly  150 . Although in some circumstances the medical device holder  162  may be permanently attached to the crimping device  160 , it is slideably attached to the crimping device  160  in the second exemplary embodiment. 
     FIGS. 37 and 38  are top views of the crimping device  160  in accordance with the second exemplary embodiment where the medical device holder  162  is shown attached to the crimping device  160  in  FIG. 37  and shown unattached in  FIG. 38 . The medical device holder  162  has a mortise  164  for accepting a tenon  166  of the crimping device  160 . In many situations, the medical device assembly is secured within the medical device holder  162  prior to delivery at the surgical site. The surgeon slides the medical device holder  162  onto the crimping device  160  and secures the crimp connector  100  into the connector holder  40  as described above. After the medical wire  110  is secured in the medical wire holder  30  and the components are properly aligned, the crimp connector  100  of the medical device assembly is crimped to the medical wire  110  while the medical device  150  is held by the medical device holder  162 . The device holder  162  may be positioned in any of several locations and orientations. For example, the device holder  162  may be positioned within the protected storage area  86  or underneath the crimper assembly  6  in some circumstances. The tenon  166 , therefore, may be located within the protected storage area  86  ( FIGS. 2 and 4 ) or in any other suitable location on the crimping device  10 . 
     FIG. 39  is a perspective view of a completed crimp connection (splice) after crimping by a crimping device  10  in accordance with the exemplary embodiment of the invention. After the connection between the implanted monofilar implantable lead  92  and the second monofilar implantable lead  93  is made, a rubber boot  168 , preferably comprised of silicone, is pulled over the crimp connector  100 . The rubber boot  168  is a rubber sleeve that is typically pulled over the medical wire  110  before the splice is completed. The rubber boot  168  is slid over the completed splice. Rubber  170 , preferably uncured silicone, is injected into the silicone rubber boot  168  to backfill the silicone rubber boot  168  and further seal the crimp connector  100 . Sutures  172  can be used to secure the rubber boot  168 . 
     FIG. 40  is a flow chart of a method of connecting a medical wire  110  in accordance with the exemplary embodiment of the invention. Although the method may be performed in a variety of environments and conditions, the method is performed at the surgical implantation site in the exemplary embodiment. 
   At step  202 , the medical wire  110  is secured in the wire holder  30 . As described above, the medical wire  110  is slid down the ramp  49  until it moves past the nose  68  of the wire retainer  60  and snaps into the wire groove  38 . 
   At step  204 , the crimp connector  100  is secured in the connector holder  40 . The crimp connector  100  is slid down the ramp  50  until it moves past the nose  68  of the connector retainer  70  to snap into the groove  48 . 
   At step  206 , the end of the medical wire is positioned within the open end of the crimp connector  100 . In the exemplary method, the relative positions of the wire holder  30  and the connector holder  40  are changed to move the crimp connector  100  toward the medical wire  110  and placed the open end of the medical wire  110  within the open end of the crimp connector  100 . 
   At step  208 , the crimp connector  100  is held in the connector holder to position the open end of the crimp connector  100  between the crimping die  74  and the anvil  20  of the crimper assembly  6 . In the exemplary method, the wire holder  30  and the connector holder  40  slide along the pin  54  toward each other to align the open end of the crimp connector  100  between the crimping die  74  and the anvil  20 . 
   At step  210 , the crimping die  74  is forced into the crimp connector  100  to deform the crimp connector  100  through the insulation of the medical wire  110  and form an electrical contact between the crimp connector  100  and the conductor of the medical wire  110 . The crimping die  74  facilitates crush-penetration of the insulation as it is moved toward the anvil  20 . 
   At step  212 , the crimping device  10  is opened. In the exemplary method, the crimp lever  72  is rotated about the pin  54  to open the crimping device  10 . 
   At step  214 , the crimp connector  100  and the medical wire  110  are removed. The completed crimp is removed by pulling the crimp connector  100  and the medical wire  110  past the connector retainer  70  and the wire retainer  60 , respectively. 
   At step  216 , the crimp connector  100  is covered with a silicone rubber boot. In the exemplary method, the surgeon backfills the boot with uncured silicone and completes the connection by applying sutures to secure the boot. In some circumstances, backfilling, sutures or the boot can be omitted. 
   Other embodiments and modifications of this invention will occur to those of ordinary skill in the art in view of these teachings. The above description is illustrative and not restrictive. This invention is to be limited only by the following claims, which include all such embodiments and modifications when viewed in conjunction with the above specification and accompanying drawings. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.