Abstract:
A neuromonitoring needle electrode placement gun which includes a housing, at least a first needle electrode and housing assembly, an elongated channel dimensioned and configured for accommodating axial movement of the at least a first needle electrode and housing assembly within the channel and for directing movement of the at least a first needle electrode and housing assembly and a pusher dimensioned and configured for engaging the at least a first needle electrode and housing assembly and for axially displacing the at least a first needle electrode and housing assembly.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a division of United States patent application entitled NEUROMONITORING NEEDLE-CARTRIDGE GUN SYSTEM having an application Ser. No. 14/176,109, a filing date of Feb. 9, 2014 and which matured into U.S. Pat. No. ______ on ______. 
     
    
     TECHNICAL FIELD 
       [0002]    Intraoperative neurophysiological monitoring (IONM) is a real-time assessment of neurological function involving the brain, spinal cord and related nerve structures. IONM facilitates the surgical process and reduces surgical risk by enabling a neurotechnologist (NT) to alert the surgeon if and when spinal cord or neural structure compromise appears imminent. Neuromonitoring is used for spine surgeries, as well as other types of surgical procedures such as craniotomies, total hip replacement and vascular procedures. The purpose of IONM is to reduce the risk to the patient of iatrogenic damage to the nervous system, and/or to provide functional guidance to the surgeon and anesthesiologist. IONM techniques have significantly reduced the rates of morbidity and mortality without introducing additional risks. By doing so, IONM techniques reduce health care costs, 
         [0003]    To accomplish these objectives, a member of the surgical team with special training in neurophysiology obtains triggered and spontaneous electrophysiologic signals from the patient periodically or continuously throughout the course of the operation. Patients who benefit from neuromonitoring are those undergoing operations involving the nervous system or which pose risk to its anatomic or physiologic integrity. In general, a trained neurophysiologist attaches a computer system to the patient using stimulating and recording electrodes. Interactive software running on the system carries out two tasks: 
         [0004]    1. Selective activation of stimulating electrodes with appropriate timing, and 
         [0005]    2. Processing and displaying of the electrophysiologic signals as they are picked up by the recording electrodes. 
         [0006]    IONM records impulses generated by electrical stimulation of peripheral nerves and dermatomes. Using the International EEG 10-20 electrode placement system, cortical needle electrodes are precisely placed subcutaneously to record sensory responses at specific locations associated with the spinal column and along the course of related peripheral nerves. 
         [0007]    Data generated by intraoperative neurophysiological monitoring (IONM) provides a measurement of latency (time it takes for a nerve impulse to travel from a specific point of stimulation to a specific recording site), amplitude (strength of that impulse), and wave form definition. These recordings are called somatosensory and dermatome evoked potentials. 
         [0008]    Needle electrodes are inserted into associated muscle groups to monitor spontaneous and electrically evoked myogenic activity. More particularly, in a typical procedure the neurotechnologist (NT) applies multiple stimulating surface electrodes in the pre-operative holding area. Sterile sub-dermal and intramuscular needle electrodes are inserted after induction and approval of the anesthesiologist. This process is done such that preparation of the patient continues unimpeded. The type of surgery will dictate the number of attached electrodes, which can vary significantly from 15 to 60. 
         [0009]    The present invention is generally directed to a system for applying neuromonitoring needles to a patient and the means to connect to monitoring equipment. 
       BACKGROUND OF THE INVENTION 
       [0010]    Intraoperative Neuromonitoring is used during surgery in or near the central or peripheral nervous system. It provides a valuable tool for assessing the integrity of certain neurologic pathways/tracts of a patient during surgery. Such monitoring helps in early identification of adverse events intraoperatively as well as providing a valuable tool for assessing the integrity of certain neurologic pathways/tracts of a patient during surgery. The monitoring typically requires placement of 16-32 subdermal needle electrodes in a patient. 
         [0011]    Patients benefit from neuromonitoring during certain surgical procedures, namely any surgery where there is risk to the nervous system. Most neuromonitoring is utilized by spine surgeons or neurosurgeons, but vascular, orthopedic, otolarygologists and urology surgeons have all utilized neuromonitoring as well. 
         [0012]    Neuromonitoring utilizes subdermal needle electrodes that are shallowly placed in the patient. The needles remain in place during surgery and are removed after the operation. Patients are often repositioned for transport or other reasons while needles are still in place. 
         [0013]    Needle tips can reemerge during moving, repositioning, and handling of the patient. Needle sticks, are a general problem in such procedures. There are an estimated 3.5 million needle sticks worldwide annually. The cost for remediation of each needle stick injury is estimated to be about $2,500. The Needle stick Safety and Prevention Act signed into law on Nov. 6, 2000 revised the Occupational Safety and Health Administration&#39;s (OSHA) standard regulating occupational exposure to blood borne pathogens, including the human immunodeficiency virus, the hepatitis B virus, and the hepatitis C virus. 
         [0014]    From the above, it is therefore seen that there exists a need in the art to overcome the deficiencies and limitations described herein and above. 
       SUMMARY OF THE INVENTION 
       [0015]    It is an object of the present invention to minimize the risk of needle sticks during implant in the patient, during implant in the patient and withdrawal from the patient. 
         [0016]    It is another object of the present invention to more rapidly and precisely implant neuromonitoring needles. 
         [0017]    It is yet another object of the present invention to eliminate many of the conventional additional materials and procedures for securing needles to the patient. 
         [0018]    It is a still further object of the present invention to assure safety and ease of needle disposal after withdrawal from the patient by automatically providing structure to minimize human exposure to the needles after withdrawal. 
         [0019]    It is still another object of the present invention to provide a complete integrated needle delivery system for use at an operating site that is ready to function without additional preparation other than removing the system from a single sterile package. 
         [0020]    Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. 
         [0021]    The recitation herein of desirable objects which are met by various embodiments of the present invention is not meant to imply or suggest that any or all of these objects are present as essential features, either individually or collectively, in the most general embodiment of the present invention or in any of its more specific embodiments. 
         [0022]    It has now been found that one form of the present invention includes a neuromonitoring needle electrode placement gun which includes a housing, an elongated channel having an axis and an axial extremity which is a discharge end, the elongated channel has an interior dimensioned and configured for receiving a plurality of associated needle electrode cartridges. Each includes at least one needle electrode having an exposed point and the plurality of associated needle electrode cartridges are each disposed at axially successive positions along the axis within the elongated channel with each of the exposed points extending toward the discharge end. The elongated channel is carried by the housing and a trigger is mounted for pivotal movement on the housing and a pusher cooperates with the trigger. The pusher is dimensioned and configured for engaging an associated needle electrode cartridge within the plurality of associated needle electrode cartridges that is nearest to the discharge end. 
         [0023]    In one embodiment the neuromonitoring needle electrode placement gun further includes a cassette having a plurality of shelves carried by the housing. The shelves are dimensioned and configured for receiving associated coils of wire attached respectively to each of the needle electrode cartridges. 
         [0024]    Other forms of the present invention further include a cartridge for cooperation with an associated neuromonitoring needle electrode placement gun which includes a housing; at least one elongated needle electrode, having an axial extent and having a pointed axial extremity, carried by the housing as well as at least a first generally planar wing having first and second faces thereof. The first generally planar wing is carried by the housing in some embodiments 
         [0025]    Some embodiments of the cartridge further include at least a first generally planar wing that is coated with a releasable adhesive on a first face thereof. The cartridge may have engagement surfaces disposed on opposed sides thereof, the engagement surfaces may be dimensioned and configured for cooperation with an elongated track in the associated neuromonitoring needle electrode placement gun. Each cartridge may further include a wire fixed to the at least one needle electrode for conducting either a stimulus for a patient or a patient&#39;s response to a stimulus. Each needle electrode may have insulation surrounding an axial portion of the axial extent of the at least one elongated needle electrode and insulation may surround an axial portion of the axial extent of the at least one elongated needle electrode that is spaced a predetermined distance from the pointed axial extremity. The cartridge may further include a second elongated needle electrode having an axial extent and having a pointed axial extremity carried by the housing and the first and second elongated needle electrodes may be disposed in coplanar relationship. In addition the first and second elongated needle electrodes may have the respective pointed axial extremities thereof disposed in perpendicular relationship to and abutting a virtual line that is coplanar with the first and second elongated needle electrodes. 
         [0026]    The first and second elongated needle electrodes in some embodiments are spaced apart a distance corresponding to a distance suitable for a differential amplifier to obtain an optimal response from the needle electrodes. In some embodiments both needles in a given pair may measure spontaneous myogenic activity. In other embodiments one needle in a given pair may provide a stimulus and the other needle in the pair may be used to measure evoked myogenic activity. The respective engagement surfaces may be dimensioned and configured for engagement with associated elongated channels in an associated neuromonitoring needle placement gun. Each cartridge may further include a second generally planar wing having first and second faces, the second generally planar wing may also be carried by the housing. 
         [0027]    The cartridge may have the first and second generally planar wings carried on the housing by a pivotal mounting dimensioned and configured to permit movement of the first and second generally planar wings to a position wherein the first and second generally planar wings are disposed in parallel overlapping relationship. The cartridge may have the first and second generally planar wings dimensioned and configured for passage within a slot within the associated neuromonitoring needle electrode placement gun. The first and second generally planar wings carried on the housing by a pivotal mounting dimensioned and configured to permit movement thereof to a position wherein the first and second generally planar wings may be disposed in parallel overlapping relationship and the wings shield the respective pointed axial extremities to prevent either intentional or inadvertent contact with the respective pointed axial extremity of each of the elongated needle electrodes. 
         [0028]    The cartridge may have the first and second generally planar wings carried on the housing by a pivotal mounting dimensioned and configured to permit movement of the first and second generally planar wings to a position wherein the first and second generally planar wings are disposed in parallel overlapping relationship. The cartridge may have the first and second generally planar wings dimensioned and configured for passage within a slot within the associated neuromonitoring needle electrode placement gun. The first and second generally planar wings carried on the housing by a pivotal mounting dimensioned and configured to permit movement thereof to a position wherein the first and second generally planar wings may be disposed in parallel overlapping relationship and the wings shield the respective pointed axial extremities to prevent either intentional or inadvertent contact with the respective pointed axial extremity of each of the elongated needle electrodes. 
         [0029]    The first and second generally planar wings carried on the housing are movable to a position wherein the first and second generally planar wings are substantially coplanar in some embodiments and one side of each of the first and second generally planar wings may be coated with a releasable adhesive suitable for simultaneous engagement with the skin of an associated patient. 
         [0030]    The invention also includes a neuromonitoring needle electrode placement gun which includes a housing; at least a first needle electrode and housing assembly; an elongated channel dimensioned and configured for accommodating axial movement of the at least a first needle electrode and housing assembly within the channel and for directing movement of the at least a first needle electrode and housing assembly; and a pusher dimensioned and configured for engaging the at least a first needle electrode and housing assembly and for axially displacing the at least a first needle electrode and housing assembly. 
         [0031]    In some embodiments the gun further includes a plurality of needle electrode and housing assemblies disposed in the channel. In some embodiments of the gun each needle electrode and housing assembly includes a needle electrode having a free end and a second end engaging the housing. The neuromonitoring needle electrode placement gun may have a discharge axial extremity and each needle electrode and housing assembly is oriented in the channel with the free end of each needle electrode facing the discharge axial extremity. 
         [0032]    The neuromonitoring needle electrode placement gun in some embodiments may have a needle electrode and housing assembly that includes a cartridge for cooperation with an associated neuromonitoring needle electrode placement gun which includes a housing; at least one elongated needle electrode having an axial extent and having a pointed axial extremity carried by the housing; and at least a first generally planar wing having first and second faces thereof, the first generally planar wing being carried by the housing. 
         [0033]    The neuromonitoring needle electrode placement gun in some embodiments may have a needle electrode and housing assembly that includes a cartridge for cooperation with an associated neuromonitoring needle electrode placement gun which includes a housing; at least one elongated needle electrode having an axial extent and having a pointed axial extremity carried by the housing; and at least a first generally planar wing having first and second faces thereof, the first generally planar wing being carried by the housing. 
         [0034]    Each cartridge may include at least a first generally planar wing that is coated with a releasable adhesive on the first face thereof and each cartridge may have engagement surfaces disposed on opposed sides thereof, the engagement surfaces being dimensioned and configured for cooperation with the elongated channel. In addition, each cartridge may further include an electrically conducting wire fixed to the at least one needle electrode for conducting either a stimulus for a patient or a patient&#39;s response to a stimulus. In addition the at least one needle electrode may have insulation surrounding an axial portion of the axial extent of the at least one elongated needle electrode. In addition the insulation surrounding an axial portion of the axial extent of the at least one elongated needle electrode may be spaced a predetermined distance from the pointed axial extremity whereby more precise results are achieved. 
         [0035]    Each cartridge may further include a second elongated needle electrode having an axial extent and having a pointed axial extremity carried by the housing. The free ends of each needle electrode in each cartridge may point in the same direction and the first and second elongated needle electrodes may be disposed in coplanar relationship and the first and second elongated needle electrodes in any cartridge may have the respective pointed axial extremities thereof disposed in perpendicular relationship to and abutting a virtual line that is coplanar with the first and second elongated needle electrodes. 
         [0036]    The first and second elongated needle electrodes in any cartridge may be spaced apart. Each neuromonitoring needle electrode placement gun may have a cartridge that includes a second generally planar wing having first and second faces thereof, the second generally planar wing being carried by the housing. The first and second generally planar wings are carried on the housing by a pivotal mounting dimensioned and configured to permit movement of the first and second generally planar wings to a position wherein the first and second generally planar wings are disposed in parallel overlapping relationship. 
         [0037]    The first and second generally planar wings may be dimensioned and configured for passage within the elongated channel. The first and second generally planar wings may be carried on the housing by a pivotal mounting dimensioned and configured to permit movement thereof to a position wherein the first and second generally planar wings are disposed in parallel overlapping relationship and the wings shield the respective pointed axial extremities to prevent either intentional or inadvertent contact with the respective pointed axial extremity of each of the elongated needle electrodes. 
         [0038]    The first and second generally planar wings carried on the housing may be movable to a position wherein the first and second generally planar wings have planar surfaces thereof moveable to a position where the planar surfaces are in abutting relationship. In some embodiments one side of each of the first and second generally planar wings is coated with a releasable adhesive suitable for simultaneous engagement with the skin of an associated patient. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0039]    The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of practice, together with the further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which: 
           [0040]      FIG. 1  is a perspective view of an embodiment of a neuromonitoring needle-cartridge gun  10  assembly in accordance with one form of the present invention. 
           [0041]      FIG. 2  is a front view of the assembly shown in  FIG. 1 . 
           [0042]      FIG. 3  is a perspective view of an embodiment of a needle and wire assembly that is incorporated into another assembly and then utilized with gun assembly shown in  FIG. 1 . 
           [0043]      FIG. 4  is a perspective view of an embodiment of the needle and wire assembly shown in  FIG. 3  to which a needle block has been molded resulting in a needle and wire block assembly. 
           [0044]      FIG. 5  is another perspective view of the embodiment illustrated in  FIG. 4 . 
           [0045]      FIG. 6C  is a side view of pivotally mounted “wings” that are attached to the needle and wire block assembly shown in  FIG. 5 . 
           [0046]      FIG. 6A  and  FIG. 6B  are enlarged section details of the apparatus shown in  FIG. 6C  illustrating respectively the spring actuated rotation of the top wing and spring loading of the top wing. 
           [0047]      FIG. 7  is an exploded view illustrating a pair of wings that are dimensioned and configured to be snapped onto the needle block assembly. 
           [0048]      FIG. 8  is another view further illustrating a pair of wings that are both dimensioned and configured to be snapped onto the needle block assembly 
           [0049]      FIG. 9  is a partially schematic and section view illustrating the construction of an embodiment in which the needles are secured within the gun in a manner that precludes any touching of the needles after loading the needles into the gun and immediately prior to placement in a patient. 
           [0050]      FIG. 10  is a partially schematic view of a connection between a wire coil, with connectors, and the needle assembly that is adhered to the patient. 
           [0051]      FIG. 11  is an enlarged side view of the needle assembly, shown in  FIG. 10 , applied to a patient. 
           [0052]      FIG. 12  shows the needle assembly after removal from the patient. 
           [0053]      FIG. 13  is a partially broken-away side view of the overall gun  10 , fully loaded with a plurality of needle and wire block assemblies that are ready to fire for subdermal implant of the axial extremities of the respective needles in a patient. 
           [0054]      FIG. 14  is an enlarged partially schematic view of the trigger area of the apparatus shown in  FIG. 13 . 
           [0055]      FIG. 15A  is a perspective view of a twin pusher element of the gun  10  constructed to positively urge each of the respective needles in a given needle assembly for subdermal implant of the axial extremities of the respective needles in a patient. 
           [0056]      FIG. 15B  is a partially schematic view illustrating the manner of engagement between the twin pusher element illustrated in  FIG. 15A  and a given needle block immediately prior to subdermal implant of the axial extremities of the respective needles in a patient. 
           [0057]      FIG. 16A  and  FIG. 16B  are respectively side and bottom views of an axial part of a column of needle assemblies each carrying a respective bottom wing  20  and top wing  21  permanently joined onto a ribbon that sequentially advances respective needle assemblies. 
           [0058]      FIG. 17  schematically illustrates the manner in which a needle assembly is propelled fully forward and particularly illustrates a piece of release paper disposed over adhesive disposed on both the top and bottom wings of a respective needle assembly. 
           [0059]      FIG. 18  schematically illustrates the next sequential step in an embodiment of the present invention in which after the axial extremities of the needles are subdermal implanted and removal of the release paper a small spring moves the top wing up to display an instruction to the operator to press the wings against the skin of the patient (to avoid needle sticks) preparatory to withdrawal of gun  10  away from the area of the subdermal implant. 
           [0060]      FIG. 19  is a partially schematic representation at an initial position of a part of the gun  10  that is simplified by representing complete needle assemblies by needle blocks to improve clarity. 
           [0061]      FIG. 20  is a partially schematic simplified representation similar to that shown in  FIG. 19  where the needle assemblies are advanced a partial pitch length wherein the term “pitch length” refers to the length between successive needle assemblies. 
           [0062]      FIG. 21  is a partially schematic simplified representation similar to that shown in  FIG. 19  where the needle assemblies are advanced a complete pitch length wherein the term “pitch length” refers to the length between successive needle assemblies. 
           [0063]      FIG. 22  is a partially schematic representation of the ribbon extending between respective needle assemblies and having respective opposed notches at axially spaced intervals of the ribbon and particularly showing an axial part of the ribbon having opposed notches registered with a parting blade. 
           [0064]      FIG. 23  is a partially schematic simplified representation similar to that shown in  FIG. 21  where the needle assemblies are further advanced with the needles in the patient whereby the ribbon is axially moved forward with its needle block concurrently with an axial part of the ribbon having opposed notches registered with a parting blade and thereby initiating a tear in the ribbon at the axial part of the ribbon having opposed notches. 
           [0065]      FIG. 24  is a representation of the tearing of the ribbon as a consequence of the movement illustrated in  FIG. 23 . 
           [0066]      FIG. 25  illustrates a parting blade comprising a long arm with the blade to induce parting of the ribbon at one end bent to a right angle and the other end pivotally mounted to the trigger. 
           [0067]      FIGS. 26 and 27  are respectively vertical and horizontal sectional views of the front end of the gun. 
           [0068]      FIGS. 28 and 29  are isometric views of one embodiment of the trigger. 
           [0069]      FIG. 30  is an isometric view of an individual shelf  28  in the cassette  26  illustrating a coiled extension  24  of insulated wire pair  23  disposed thereon. 
           [0070]      FIG. 31  is a cut-away side view of an alternate embodiment, in which needle assemblies are pre-loaded into a magazine, which is then slid all the way into the front end of the gun. 
           [0071]      FIG. 32  is a scaled-up cross-section view the magazine of the alternate embodiment. 
           [0072]      FIG. 33  is a scaled-up front-end view of magazine  72  of the alternate embodiment loaded with needle assemblies. 
           [0073]      FIG. 34  is a top view of magazine  72  in the alternate embodiment, which runs the full length through the gun. 
           [0074]      FIG. 35  is an isometric view of the bottom of magazine  72  in the alternate embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0075]    While the invention has been described in detail herein in accordance with certain preferred embodiments thereof, many modifications and changes therein may be effected by those skilled in the art. Accordingly, it is intended by the appended claims to cover all such modifications and changes as fall within the spirit and scope of the invention. 
         [0076]    The apparatus and method for applying neuromonitoring needles to a patient and the means to connect to monitoring equipment are shown in  FIGS. 1-30 . The present invention provides a neuromonitoring needle-cartridge gun  10  having a handle  10   a  and a body  10   b  best shown in  FIGS. 1-2 . The gun  10  cooperates with respective twin needle and wire block assemblies  16 . Each twin needle and wire block assembly  16  comprises a twin needle assembly  13  with insulated wire pair  23  and connectors  13   a  as shown in  FIG. 3  and  FIG. 2  respectively, which further includes a molded block  18  extending over a part thereof as shown in  FIG. 4 . 
         [0077]    The respective needles  11  in a twin needle and wire block assembly  16  are propelled into the patient with a single trigger  22  pull. In a preferred embodiment, it makes no difference if the operator holds or releases the trigger  22  after making an initial trigger  22  pull. After securing the needles  11  (and thereby twin needle and wire block assembly  16  to the patient, the gun  10  is withdrawn, whereupon a coiled extension  24  of insulated wire pair  23  with connectors  13   a  is extended from a wire cassette  26 . 
         [0078]      FIG. 2  shows the gun  10  from a front view. The gun  10  is loaded with twin needle and wire block assembly  16  and their associated coil of twin-lead wire  24 , with connectors. Each coil of twin-lead wire  24  has enough wire to travel from the needle  11  placement in the patient to the monitoring equipment (not shown), where the connectors  13   a  are attached after placement of the respective needles in the patient. The coils of twin-lead wire  24  are stacked in a cassette  26 . The cassette  26  has a plurality of parallel shelves  28 . The cassette has an open front whereby respective coiled extension  24  of insulated wire pair  23  are respectively dragged out of the cassette  26  after a trigger  22  pull as the gun  10  is moved away from the patient. 
         [0079]    Respective coiled extensions  24  of insulated wire pairs  23  with connectors  13   a  are stratified in an orderly manner, so that the top coiled extension  24  of insulated wire pair  23  with connectors  13   a  comes out of the cassette  26  first followed sequentially by the next highest coiled extension  24  of an insulated wire pair  23 . Thus, there is no crossing or tangling of wires. The view of  FIG. 2  shows twelve wire coils  24  with connectors  13   a  disposed in the gun  10 . The quantity of wire coils may be more or less in various embodiments of the present invention. 
         [0080]    The needles  11  in the gun track  12  are aimed directly out the open end as shown in the left (as viewed) part of  FIG. 1  as well as  FIGS. 26 and 27 . Until the trigger  22  is actuated, the needles  11  are recessed in the track  12 . Accordingly, the needles  11  cannot be touched either inadvertently or intentionally. In this embodiment, the cassette shelves  28  have a “zigzag” step in which respective coiled extensions  24  of insulated wire pairs  23  are stacked alternately upside-down and upside-up to conserve space with connectors  13   a  off to one side. Embodiments of the present invention employ such arrays to lower the overall stack height and thereby result in a lower profile to the overall apparatus. More specifically as shown in  FIG. 2 , the connectors  13   a  appear as two side-by-side stacks of twin connectors. Each pair of connectors  13   a  is attached to a full-width coil of wire  24 , and the wire and connector assemblies are stacked alternately, one up, one down. The uppermost coil  24  with connectors  13   a  is connected to the front-most needle and wire assembly  14  on the needle output deck  32  of the gun  10 . Other embodiments may utilize a community mailbox like set of pigeonholes to receive respective coiled extension  24  of an insulated wire pair  23 . 
         [0081]      FIG. 3  illustrates the construction of a twin needle assembly  13 . Each conductor of an insulated wire pair  23  is permanently joined in electrical contact with a respective needle  11  in a twin needle assembly  13 . These two conductors become an insulated wire pair  23  at the midpoint between the needles  11 , and extend rearward relative to needle  11  direction as best seen in  FIG. 3 . Each needle  11  is provided with a tight-fitting insulating sleeve  11   a , such as shrink tube, so that insulating sleeve exposes a precise length of the axial extremity of each needle  11   a . This is to satisfy requirements of the monitoring equipment for accuracy of nerve impulse measurements. 
         [0082]    The twin needle and wire block assembly  16  consists of a twin needle assembly  13  and a molded block  18 . A higher assembly that further includes wings  20  and  21  is shown in  FIG. 6C  and  FIG. 7 . 
         [0083]      FIG. 4  shows a molded block  18  molded over the needles and the wires. The insulated wires exit the block centrally as a “twin-wire” joined pair (destined for the “wire cassette”). A molded block  18  spans the width of the track  12  in the gun  10 , and pivotally supports a bottom wing  20  and a top wing  21  best seen in  FIG. 7 . The wings  20 ,  21  secure the assembly to the patient. 
         [0084]      FIGS. 6A, 6B, 6C  and  FIG. 7  illustrate the relationship of pivotally mounted wings  20 ,  21  to the molded block  18 . The upper or top wing  21  is spring loaded by a little low force wire-form spring  30  placed inboard on the pivot pin prior to snapping on the wing  21 . This spring  30  urges the upper wing  21  to swing up to its initial installed vertical position as shown in  FIG. 6A . This movement of the upper wing  21  in response to the bias of the spring  30  occurs after the needle assembly  14  is propelled to the output deck  32  of the gun  10  in the customary use of the illustrated embodiment of the present invention. The respective pairs of wings  20 ,  21  are respectively snapped on coaxial bottom pins  14   a  and coaxial upper pins  14   b  carried by the molded block  18 . The upper wing  21  retains the spring  30 , as noted above. The spring  30  cannot escape from its installed position due to the loops at each end (best seen in  FIGS. 6A and 6B .), which will not fit through the cracks of the structure. Coaxial bottom pins  14   a  disposed at the opposed axial extremities of the molded block  18  extend out beyond coaxial upper pins  14   b  also disposed at the opposed axial extremities of the molded block  18 . The coaxial bottom pins  14   a  ride in grooves on opposed sides of the gun track  12  in order to provide further guidance for the needle and wire assembly  14  as it advances along the track  12  in the gun  10 . 
         [0085]    The two-spaced rectangular open-ended cutouts  20   a  (shown in  FIG. 7 ) in the lower wing  20 , provide clearance for the pusher rails  34  to extend behind a needle and wire block assembly  16  that is next to be pushed. See  FIGS. 15A, 15B, 16A, and 16B . 
         [0086]    The wings  20 ,  21  each have an adhesive coating, protected from exposure until use, by a layer of release paper that is easily pulled off by the operator at the time of application to the patient. The top wing  21  has the adhesive on the broad flat top surface thereof and the bottom wing  20  has the adhesive on the broad flat bottom surface thereof. The operator exposes the adhesive on the pivotally mounted wings  20 ,  21  and presses the respective adhesive surfaces thereof to the skin of the patient being monitored and thereby secures the assembly to the patient. 
         [0087]    A preferred embodiment described herein contains 12 needle assemblies lined-up in the gun track  12 , and corresponding 12 sets of wires including connectors  13   a , tucked in a stratified manner into the wire cassette above the track  12 . The needle assemblies are lined-up nose-to-tail, not counting the needles, which ride below the wing  20  of the preceding assembly. 
         [0088]    As best seen in  FIG. 9  the points of the needles  11  do not touch anything at any time prior to subcutaneous placement in a patient. The needles cannot drop to the track  12  floor because the roof of the gun track  12  holds down the upper wing  21 , and that wing  21  bears against the needle and wire block assembly  16  and thus prevents the needle and wire block assembly  16  from rotating downward with the needle  11 . 
         [0089]    As best seen in  FIG. 10  the coil of twin-lead wire  24  is connected by connectors  13   a  to a needle and wire block assembly  16  that is adhered to the patient P. The wire coil  24 , with its connectors, is dragged from one of the respective shelves  28  in the cassette  26 . The coil  24  includes a long free wire upon pulling the coiled extension  24  of insulated wire pair  23  away from a relatively low tack adhesive patch  70  that initially secures the coiled extension  24  of insulated wire pair  23  to one of the shelves  28  in the cassette  26 . Some of the low tack adhesive patch  70  is made to stick to one of the shelves  28  and will release upon the coiled extension  24  of insulated wire pair  23  being dragged as the gun is moved away from the patient P. The main body of adhesive faces the coil  24 , and holds it neatly coiled until the operator manually removes the low tack adhesive patch  70  from the coiled extension  24  of insulated wire pair  23 . Then the full length of the previously coiled extension  24  of insulated wire pair falls free, ready to be drawn over to the monitoring equipment. This can be done whenever the operator is ready, even after all needles are attached to the patient, and the patient is positioned as desired. The gun track  12  of the gun  10  is elongated. The other axial extremity of the coiled extension  24  of insulated wire pair  23  is fixed to the insulated wire pair  23  that is dimensioned to allow free movement of the needles  11  through the track  12 . 
         [0090]      FIG. 11  is an enlarged view of the needle and wire block assembly  16  applied to a patient. The angle of entry for the needles is determined by the operator aiming the gun  10 . The mounting of the wings  20 ,  21  permits angular travel to any desired angular orientation about the respective mounting axis thereof and thus the adhesive surfaces thereof can be applied to the skin of the patient. The wings  20 ,  21  are designed for ease of removing the assembly from the patient. A fingernail tab  40  assists in lifting the bottom wing  20  from the patient. The rest of the assembly is stripped from the patient by pulling the upper wing  21  and the wire. The insulated wire pair  23  in a preferred embodiment is ruggedized and securely mounted in the needle and wire block assembly  16 . 
         [0091]      FIG. 12  shows the needle and wire block assembly  16  after removal from the patient. The wings  20 ,  21  are disposed in planar face to planar face contact. The respective planar faces immediately stick to each other because they still have the adhesive that stuck to the skin of the patient. The needles  11  are obscured between the wings  20  and  21 , and thus protected from both intentional and unintentional contact by anybody. Post-operative cleanup is now much safer than in prior art manual procedures because there are no exposed needles  11 . The rugged insulated wire pair  23  functions as a lanyard that can be pulled as needed during removal. 
         [0092]      FIG. 13  is a partially cut-away side view of the overall gun  10 , fully loaded and ready to fire. The trigger  22 , also shown in  FIGS. 28, 29  is a lever, which can be operated by one or more fingers. A bi-directional anti-backup trigger pawl  42  engages a rotary ratchet  44  on the rear of the trigger  22  after the trigger  22  has been moved a short distance from the initial position. It will be understood that the rotary ratchet  44  formed on a planar member is rigidly fixed to the trigger  22  and thus has the same center of rotation as the trigger  22 . (In some embodiments, the rotary ratchet  44  and the rest of the trigger  22  are manufactured from a single piece and that piece is metal.) Because of the bi-directional anti-backup trigger pawl  42  engagement with the rotary ratchet  44  on the rear of the trigger  22  the trigger  22  must be fully actuated before the trigger  22  can reset back to the initial position. The trigger pawl  42  also works in the other direction, so that once the trigger has moved away from the handle  10   a , the trigger  22  must return to the initial position where the trigger is spaced from the handle the maximum possible distance before another firing cycle can occur. A trigger pawl spring  43  pulls the spring-loaded bi-directional pawl  42  to its central waiting or default position. In addition, the trigger  22  has motion limit stop  48  to preclude over-travel. 
         [0093]      FIG. 14  is a view of the trigger  22  area of the  FIG. 13 . Also shown are simplified views of parts needle and wire block assembly  16  (just needles and needle blocks) to illustrate how the needles  11  ride in the gun track  12  including illustrating how the points of the respective needles  11  travel without interference. The respective legs of the pusher rail  34  are propelled forward when the trigger  22  is actuated. More particularly the pusher rail  34  is propelled by an elongated link  50  riding on an arcuate cam ramp  52 . Return force for combined pusher rail  34 , elongated link  50  and trigger  22  is provided by a trigger return spring  55  connecting the pusher rail  34  to a fixed point  54  on the gun  10 . The trigger return spring  55  is disposed in a different plane than the arcuate cam ramp  52  to avoid interference. The trigger return spring  55  also provides an upward force for the pusher rail  34 , so that the pusher rail  34  will snap in behind the next-in-line needle and wire block assembly  16 , upon trigger  22  return (reset) to the initial position as shown in  FIG. 13 . The horizontal travel of the forward arm  56  of the trigger  22 , which drives the ribbon-parting blade  62  is non-linear, and stays at nearly the same horizontal location for the last half of the trigger actuation so the parting blade remains where needed. This positions the blade for ribbon parting synchronized with the pusher displacement. The blade is cammed up with appropriate timing, as seen later in  FIGS. 19-24 . 
         [0094]      FIG. 15  shows the pusher rail  34  comprising first and second parallel elongated legs. Each leg of the pusher rail  34  extends through one of open-ended cutouts  20   a  of the bottom wing  20  to engage a needle and wire block assembly  16 . The spaced legs of the pusher rail  34  simultaneously engage spaced apart lateral portions of the needle and wire block assembly  16 . This arrangement insures stability of the needle and wire block assembly.  FIG. 15B  is a side cut-away view showing the pusher rails back at the home position, ready to propel the next-in-line needle and wire block assembly  16  each carrying a respective bottom wing  20  and top wing  21 . The push of the pusher rail  34  implants the needles  11  subcutaneously in the patient as best seen in  FIG. 17 . 
         [0095]      FIGS. 16A and 16B  respectively illustrate a side view and a bottom view of an axial part of a column of needle and wire block assembly  16  carrying a bottom wing  20  and a top wing  21  each joined to a ribbon  36 . The distance between identical points on each of two successive needle and wire block assembly  16  is the pitch of the column. The entire column moves one pitch length forward in the gun track  12  when the trigger  22  is cycled between an initial position (as shown) to a fully depressed position. The legs of the pusher rail  34  on the needle and wire block assembly  16  nearest the discharge axial extremity of the track  12  advances both that individual needle and wire block assembly  16  as well as the ribbon  36  and all the other needle and wire block assemblies  16  (each carrying a respective bottom wing  20  and top wing  21 ) attached to the ribbon  36 . The ribbon  36  is provided with a pair of opposed notches  36   a  at one pitch length intervals along the axial extent of the ribbon  36 . The wing  20  clearance cutout areas  20   a , shown in the bottom view, allow the pusher  34  legs to get behind the needle and wire block assembly  16  nearest the discharge end of the track  12  to accurately advance both that needle and wire block assembly  16  with the top and bottom wings secured thereto as well as the trailing ribbon and other attached needle and wire block assemblies  16  with their respective top and bottom wings secured thereto. 
         [0096]      FIG. 17  illustrates the position of a needle and wire block assembly  16  propelled fully forward. A message for the gun  10  operator is automatically presented. Each needle assembly comes with a respective piece of release paper extending over the adhesive on each of the top and bottom wings  20  and  21 . Each such release paper overlaps the adhesive slightly to make its removal easier. The top release paper has the printed message illustrated in  FIG. 17 . This message is prominently presented when the needle and wire block assembly  16  is fully propelled as the result of the trigger  22  being fully actuated. Accordingly, the needles  11  have been propelled into the patient (not shown). The release paper  58  extends back under the top of the gun track  12  in order to retain the position of that spring-loaded wing until the release paper in removed. Upon removal of the release paper  58 , the spring  30  also shown in  FIGS. 6A-6C  swings the wing  21  upward as shown in  FIG. 18 . 
         [0097]      FIG. 18  shows the next step for the operator after the step illustrated in  FIG. 17 . Upon removing the release paper  58 , the spring  30  swings the top wing  21  up to where the next message is prominently displayed. After a respective pair of needles  11  is positioned in the patient (not shown) and the operator presses the wing  21  against the skin of the patient. This secures the needle and wire block assembly  16  to the patient, and the gun  10  is drawn away. As the gun  10  is drawn away, the wire coil  24 , with connectors  13   a , comes out of the cassette  26 . The operator removes the release paper  58  from the bottom wing  20  and presses the bottom wing  20  to the skin of the patient. Upon removing the adhesive patch  30  from the wire coil  24  and its connectors  13   a , a long length of wire is released to deliver the connectors  13   a  to the measurement equipment (not shown). 
         [0098]      FIGS. 19-24 , show the operation inside the front of the gun  10  during a firing cycle. The ribbon  36 , having a plurality of attached needle and wire block assemblies  16  each with an attached top wing  21  and bottom wing  20  is drawn forward. Thereafter, the ribbon  36  is severed so that the then front most needle and wire block assembly  16  each with an attached top wing  21  and bottom wing  20  attached and its associated coiled extension  24  of insulated wire pair  23  can exit the gun  10  while the ribbon with the attachments thereto is held in place. A spring loaded anti-backup pawl  43  is constantly blocking the plurality of needle and wire block assemblies  16  that are collectively referred to herein as a column. More particularly the anti-backup pawl  38  blocks the column from slipping backward. The column has enough friction with respect to the gun track  12  so that the column will resist slipping forward. Upon the occurrence of very unusual circumstances, such as dropping the gun  10  on a hard table surface, the operator will initiate a “clearing” cycle to insure no malfunction has or will occur. This returns the mechanism to a normal condition with everything back to normal, minus one needle and wire block assembly  16  each with an attached top wing  21  and bottom wing  20  attached and its associated coiled extension  24  of insulated wire pair  23 . The anti-backup pawl  38  cooperates with a wire-form spring  66  molded into the body thereof at the pivot for the pawl  38 . The pawl  38  is biased by the spring  66 . The other end of the wire-form spring  66  is fixed on a spring anchor pin  60  carried on the gun body  10   b.    
         [0099]      FIG. 19  shows the condition of a portion of the apparatus before, or at, the start of a firing cycle. For clarity, the view is simplified e.g., blocks  68  represent complete needle and wire block assemblies  16  together with a top wing  21  and a bottom wing  20 . 
         [0100]      FIG. 20  shows a plurality of simplified blocks  68  each representing complete needle and wire block assemblies  16  together with a top wing  21  and a bottom wing  20  advanced forward a partial pitch length. The pusher pair (not shown) is bearing on the rear most surface of the leading complete needle and wire block assemblies  16  together with a top wing  21  and a bottom wing  20 . The column is advanced forcefully over a pawl  38  (biased by pawl spring  43 ), which deflects downward. A ribbon-parting blade  62 , also shown in  FIG. 25  is starting to climb up a ribbon parting blade cam ramp  64 . (Cam ramps in this gun  10  are provided with a thin film of silicone grease.) The parting blade  62  in a preferred embodiment is not sharp and does not cut anything. It works on an altogether different principle, illustrated in  FIGS. 22, 23 and 24 . 
         [0101]      FIG. 21  shows blocks  68  representing complete needle and wire block assemblies  16  advanced one full pitch length. The pawl  38  has sprung back up to prevent rearward slippage. The ribbon  36  is attached to the needle and wire block assembly  16  with enough slack to allow the pawl  38  to move far enough upward to, once again, provide positive anti-backup for the train of needle assemblies. The parting blade  62  is cammed to its uppermost position. The ribbon  36  has opposed notches  36   a  at axial intervals equal to the pitch of the mechanism as shown in  FIGS. 16B and 22 ). An engagement surface  62   a  is now registered in the opposed notches  36   a , each having an acute included angle, with a sharp apex, to facilitate tearing of the ribbon  36 . Further motion by the twin pushers (not shown) against the forward needle block starts a tearing action in the ribbon  36  between the opposed notches  36   a . The next needle block  68  cannot advance forward during the remainder of this cycle because it is up against the rigid parting blade, which will not move. 
         [0102]      FIG. 22  shows the ribbon  36  with its opposed notches  36   a  pulled up over the engagement surface  62   a  of a ribbon parting blade  62 . The engagement surface  62   a  of a ribbon parting blade  62  is dull, whereas the opposed notches  36   a  of the ribbon  36  have an enclosed acute angle. The next sequential needle and wire block assemblies  16  together with a top wing  21  and a bottom wing  20  with its attached ribbon  36 , cannot move any farther because the engagement surface  62   a  of the ribbon parting blade  62  is in the way. Further axial pulling on the ribbon  36  by the forward needle block will cause a tear to start between the opposed notches  36   a  in the ribbon  36 . The ribbon  36  tears incrementally as the ribbon parting blade  62  and particularly the engagement surface  62   a  engages the opposed notches  36   a  so there is no sudden pop when the ribbon parts. 
         [0103]      FIG. 23  shows the front needle assembly propelled fully forward. The needles are in the patient (not shown). The ribbon  36  is forced to move forward with its needle block, and therefore forces a tear in the ribbon  36  at the opposed notches  36   a  parts the ribbon  36 . 
         [0104]      FIG. 24  shows the result of the action described above. The leftover piece of ribbon  36  simply stays with the deployed needle and wire block assembly  16 . 
         [0105]      FIG. 25  shows the complete parting blade  62 , which in the illustrated embodiment has an elongated body having a right-angle bend at one axial extremity. That axial extremity has an engagement surface  62   a . The other axial extremity is pivotally mounted to the trigger  22 .  FIG. 30  is an isometric view of an individual shelf  28  in the cassette  26  illustrating a coiled extension  24  of insulated wire pair  23  disposed thereon. 
         [0106]    The wings  20  and  21  are disposed in parallel planes when the wings are in the gun. Thereafter, upon ejection from the gun the wings rotate to whatever angle is needed for each the respective wings to have planar face contact with the patient and specifically so that the respective wings have planar face contact with the skin of the patient on each side of a given needle electrode, and are thereafter rotated further to become parallel again, but 180 degrees from original, as they obscure the needles upon removal from the patient. Thus, the wings are almost coplanar as they rest nearly against each other, with needles obscured between, and held by the adhesive thereon. 
         [0107]    Although the above description of various preferred embodiments emphasizes cartridges which support two parallel needle electrodes for simultaneous subcutaneous placement in the body of a patient, it will be understood by those skilled in the art that other embodiments may alternatively only implant a single needle electrode upon actuation of the trigger. The embodiments described above utilize a cartridge having cylindrical surfaces disposed at respective axial extremities thereof that engage respective parallel opposed channels in a track or slot. Other embodiments may change the gender of the coupling between the respective cartridges and the track or slot in which the cartridges move. For example, the respective cylindrical surfaces of each cartridge may have a slot that is dimensioned and configured for engaging respective rails on opposed sides of the track or slot. 
         [0108]    The language used in the claims and specification to describe the apparatus of the present invention may use terms such as “barrel” and “magazine” to describe embodiments of the present invention because the terms facilitate description of the apparatus despite some material differences between the apparatus of the present invention and the typical apparatus in the firearms field where the term “barrel” usually refers to an elongated cylindrical element and the term “magazine” usually refers to a mechanism for holding a plurality of cartridges or shells. As used herein the term “barrel” refers to an elongated structure that directs one or more needle electrodes toward a patient. As used herein the term “magazine” refers to a structure for holding one or more needle electrode assemblies and intended for subsequent sequential placement in a patient. 
         [0109]    In those embodiments of the present invention in which the sterile preloaded gun is sealed in a blister pack, the gun may be loaded with a fixture (not shown) that holds a plurality needle electrode assemblies in a rectilinear array aligned with the barrel. Other embodiments of the present invention utilize a magazine sleeve having an arcuate cross section holding a plurality of needle electrode assemblies whereby the loaded magazine may be inserted in the barrel of the assembly in substantially concentric relationship. 
         [0110]      FIG. 31 - FIG. 35  illustrate an alternate embodiment of the present invention.  FIG. 31  is a cut-away side view of the alternate embodiment, in which needle assemblies are pre-loaded into a magazine, which is then slid all the way into the front end of the gun. The magazine  72  is fully inserted into the gun body  10   b . The inside of the tubular magazine becomes the track  12 , along which, the needle assemblies, not shown, are carried. The output deck  32 , anti-backup pawl  38 , ribbon parting blade  62 , pusher rail(s)  34 , and the rest of the gun body  10   b  remain exactly the same as the previously described embodiment. 
         [0111]      FIG. 32  is a scaled-up cross-section view of the magazine  72 .  FIG. 33  is a scaled-up front-end view of the magazine  72  loaded with needle assemblies. The viewer sees needle and wire block assembly  16 , top wing  21 , ribbon  36 , and needle(s)  11 .  FIG. 34  is a top view of the magazine  72 , which runs full length through the gun. Slot  72   a  (full length) accommodates the wire(s)  23  (still used, but not shown in this figure) of the previously described embodiment. Cutout  72   b  accommodates the pusher rail(s)  34  (still used, but not shown in this figure). 
         [0112]      FIG. 35  is an isometric view of the bottom of the magazine  72 . It more plainly shows the cutout  72   b , which allows the pusher rail(s)  34 , not shown, to get behind, and then push, the front-most needle assembly, not shown in this figure. 
         [0113]    All publications and patent applications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. 
         [0114]    The previous description is provided to enable any person skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. Although the description above contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus, the claims are not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Furthermore, it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary. All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”