Abstract:
A nerve blocking endoscopic apparatus is disclosed having a stimulating electrode disposed at its distal end to aid in proper identification and placement of the apparatus adjacent a nerve to be blocked and to methods for making and using same.

Description:
RELATED APPLICATIONS 
       [0001]    The present invention claims the benefit and priority to U.S. Provisional Patent Application Ser. No. 61/034,092 filed 5 Mar. 2008 (Mar. 5, 2008). 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention relate to an endoscope for peripheral nerve blocks under direct observational control via the endoscope and to methods for making and using same. 
         [0004]    More particularly, embodiments of the present invention relate to an endoscope including a stimulating electrode disposed at its distal end. Such an endoscope, when properly positioned under direct observational control via the endoscope, permits effective endoscope placement and electrode stimulation of the nerve for achieving effective peripheral nerve blocks under direct control using a local anesthetic agent. The present invention also relates to methods for making and using same. 
         [0005]    2. Description of the Related Art 
         [0006]    The technology of video assisted procedures using endoscopy is available and is not new. Video assisted endoscopic procedures are used for vein harvesting, thyroid surgery, carpel tunnel release, etc. But all these techniques require a surgical incision. 
         [0007]    Presently the peripheral nerve blocks are done using indirect methods like paresthesias, peripheral nerve stimulation and ultrasound guided techniques. 
         [0008]    However, there are no video assisted endoscopic procedures available at present for the performance of peripheral nerve blocks for regional anesthesia. Thus, there is a need in the art that is satisfied by this invention, an apparatus and method for performing video assisted endoscopic peripheral nerve blocks for regional anesthesia under direct vision or through the use of a video monitor. 
       SUMMARY OF THE INVENTION 
       [0009]    Embodiments of the present invention provide an endoscope including a stimulating electrode disposed at its distal end, where the endoscope, when properly positioned under direct observational control via the endoscope via the introducer, permits effective electrode placement adjacent to a nerve to be simulated for achieving effective peripheral nerve blocks. The endoscope may also include a fluid injection conduit having an opening at or near the distal end of the endoscope. 
         [0010]    Embodiments of the present invention provide a method for performing a nerve block of a peripheral nerve including the steps of introducing an endoscope percutaneously without a surgical incision into an animal including a human. The endoscope includes an electrode disposed at or near its distal end and connected to a stimulation unit via a conducting conduit or wire. Once the endoscope has been inserted, the endoscope is pushed into a tissue of an animal including a human under direct visual control or visual control using a video monitor until the electrode is adjacent a peripheral nerve to be blocked. After the electrode is properly positioned, the nerve can be blocked using a local anesthetic injection through a fluid conduit to produce anesthesia so that a surgical procedure can then be performed. The conduit for administering anesthesia can also be used to place a stimulating catheter or a non-stimulating catheter to be left in place so that additional amounts of the anesthetic agents can be administered to the nerve to maintain the block or provide postoperative pain control. The endoscope can then be removed. 
         [0011]    Embodiments of the present invention provide an endoscopic apparatus for locating peripheral nerve blocks including a body having a proximal end and a distal end. The apparatus also includes a light delivery assembly having one light delivery conduit or a plurality of light delivery conduits and one light receiving conduit or a plurality of light receiving conduits, where each light delivery conduit is connected to a light source and terminates in the distal end of the body, and where each light receiving conduit is connected to an image processing and terminates in the distal end of the body. The apparatus also includes a fluid delivery assembly including a fluid conduit terminating in an exit port near a distal end of the body and connected to fluid delivery unit adapted to deliver fluid through the fluid conduit. The apparatus also includes a nerve stimulating assembly including a nerve simulator unit having a first electrode disposed at or near the distal end of the body and connected via a first conducting conduit to the nerve stimulator unit, and a second electrode adapted to be placed on the skin of a patient and connected via a second conducting conduit to the nerve stimulator unit to produce a voltage between the first and second electrodes, where the voltage stimulates a nerve response when the first electrode is proximal a nerve. The distal end of the body is adapted to be inserted into an animal including a human, where the progress of the insertion is monitored by the image processing and display unit so that the distal end can be properly situated adjacent a nerve to be blocked and where the nerve simulator is adapted to properly identify the nerve to be blocked and where the fluid delivery assembly is adapted to deliver a nerve blocking agent to the identified nerve. In certain embodiments, the first electrode surrounds a portion of the body near its distal end. In other embodiments, the first electrode comprises a ring. In other embodiments, the ring is a solid ring, metal foil ring, or a wire mesh ring. In other embodiments the first electrode comprises at least one electrode element. In other embodiments, the first electrode comprises a plurality of electrode element. In other embodiments the first electrode comprises a plurality of electrode element equal spaced around an outside surface of the body near the distal end of the body. In other embodiments, the apparatus further includes a catheter adapted to be fed through the fluid conduit and left in place after removal of the endoscope. In other embodiments, the fluid delivery assembly includes a Y-connector so that the type of fluid introduced into the fluid conduit can be changed. In still other embodiments, the light delivery and receiving conduits comprises optical fibers or optical fiber bundles. 
         [0012]    Embodiments of the present invention also provide a method for blocking a nerve including the step of inserting an endoscopic apparatus of this invention into a tissue site of an animal including a human. The method also includes the step of guiding the distal end of the apparatus by viewing progress of the insertion on the image processing and display unit. The method also includes the step of positioning the distal end of the endoscope adjacent to a peripheral nerve to be blocked. The method also includes the step stimulating the nerve with the stimulating electrode to identify the nerve and to ensure proper placement of the distal end of the apparatus. In certain embodiment, the method further includes the step administering a local anesthetic agent into the tissue site to block the identified nerve to produce anesthesia in the nerve so a surgical procedure can be subsequently performed. In other embodiments, the method further includes the step of inserting a catheter into the site through the fluid conduit and removing the apparatus so that the nerve can be blocked for a period of time after surgery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The invention can be better understood with reference to the following detailed description together with the appended illustrative drawings in which like elements are numbered the same. 
           [0014]      FIGS. 1A-B  depict an embodiment of an endoscope of this invention including a ring type stimulating electrode disposed at or near a distal end of the endoscope. 
           [0015]      FIGS. 1C-E  depict another embodiment of an endoscope of this invention including a stimulating electrode comprising a set of electrode ends disposed at or near a distal end of the endoscope. 
           [0016]      FIGS. 1F-G  depict another embodiment of an endoscope of this invention including a mesh type stimulating electrode disposed at or near a distal end of the endoscope. 
           [0017]      FIGS. 2A-C  depict another embodiment of an endoscope of this invention including a retractable type stimulating electrode disposed at or near a distal end of the endoscope. 
           [0018]      FIGS. 3A-F  depict a method for producing an endoscope insertion site in an animal including a human: (A) depicts a catheter with the insertion needle; (B) depicts the removal of the needle and the insertion of a guide wire into and through the catheter; (C) depicts a dilator threaded down the guide wire to expand a tissue at the insertion site; (D) depicts a trocar including a balloon threaded down the guide wire onto the dilator to further expand the tissue; (E) depicts the trocar in place after removal of the dilator and guide wire and balloon inflation, and (F) depicts the removal of the guide wire and dilator and insertion of an endoscope of this invention. 
           [0019]      FIGS. 4A-E  depict method for producing an endoscope insertion site in an animal including a human: (A) depicts a catheter with the insertion needle; (B) depicts the removal of the needle and the insertion of a guide wire into and through the catheter; (C) depicts a dilator threaded down the guide wire to expand a tissue at the insertion site; (D) depicts removal of the guide wire and insertion of a trocar including a gas conduit for pressure tissue dissection; and (E) depicts the trocar in place and the replacement of the dilator and guide wire with an endoscope of this invention. 
           [0020]      FIGS. 5A-E  depict a method for inserting an endoscope into an insertion site of an animal: (A) depicts a catheter with the insertion needle; (B) depicts the removal of the needle and the insertion of a guide wire into and through the catheter; (C) depicts a dilator threaded down the guide wire to expand a tissue at the insertion site; (D) depicts a trocar including a distal balloon and gas tissue expansion conduit threaded down the guide wire replacing the dilator to further expand the tissue; and (E) depicts the replacement of a portion of the trocar with an endoscope of this invention. 
           [0021]      FIG. 6  depict an embodiment of an endoscope of this invention including a distally disposed electrode placed proximal to a nerve to be blocked, where placement adjacent to the nerve is verified by electrode stimulation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The inventor has found that a new endoscope apparatus can be constructed with a distally disposed electrode for performing safe, efficient and effective peripheral nerve blocking. The apparatus is designed to be inserted percutaneously into a tissue of an animal including a human as a conventional endoscope. The distal end is then positioned so that the electrode is located adjacent to a nerve to be blocked to perform a nerve block. The electrode is then activated to stimulate the nerve and ensure proper placement of endoscope adjacent the nerve so that anesthesia administration can be performed safely, efficiently and effectively for the surgical procedure. This process is performed without the need for a surgical incision unlike other endoscopic procedures. 
         [0023]    The present invention broadly relates to an endoscope apparatus including a rigid or flexible body, a light source and a light conduit for transmitting light from the light source to a distal end of the body of the endoscope. The endoscope apparatus also includes a light receiving conduit having its proximal end disposed in or at the distal end of the endoscope body and its distal end in optical communication with a monitor for observing a location of the distal end of the endoscope body as it is positioned into a tissue of an animal including a human adjacent a peripheral nerve to be blocked, where proper endoscope positioning is confirmed by nerve stimulation via an electrode disposed at or near a distal end of the endoscope. The electrode is connected via a conducting conduit or wire and to an electrode stimulating unit, where the unit also includes a second conducting conduit or wire leading to a skin contact pad which acts as ground. 
         [0024]    The present invention broadly relates to a method for blocking a nerve including the step of inserting an endoscope apparatus of this invention into a tissue of an animal including a human and positioning the distal end of the endoscope adjacent to a peripheral nerve to be blocked. The electrode disposed on or at the distal end is then turned on to stimulate of the nerve to ensure proper endoscope placement under direct visual or video assisted visual control. Once proper endoscope placement is confirmed, a local anesthetic agent is then injected into the tissue site to block the appropriate nerve to produce anesthesia in its distribution of the nerve so a surgical procedure can be subsequently performed. The local anesthetic administering like a catheter can be left in place so that the nerve can be blocked for a period of time after surgery. The endoscope can then be removed. 
         [0025]    The present invention having the following general aspects that make it uniquely suited for performing nerve blocking: (1) the endoscope has a length between about 5″ and about 10″; (2) the endoscope can be rigid or flexible; (3) the endoscope can be a fiberoscope or fiberoscope fiber; (4) the endoscope is adapted to be easy to maneuver so that it can be positioned efficiently and effectively adjacent a location on a peripheral nerve; (5) the endoscope is adapted to have an excellent optical resolution; (6) the endoscope is adapted to be introduced percutaneously through a trocar or an introducer; (7) no surgical incision is needed to introduce the endoscope; (8) the trocar can optionally include a regulated side port for introduction of dilating medium for distension of the tissues if needed; (9) the trocar can optionally have a second port. This port can be used for introduction of the stimulating needle or placement of perineural catheter, placement of stimulating catheter. So, the nerve can be stimulated under direct vision or the catheter can be threaded under direct vision minimizing the chances of trauma to the nerves and the blood vessels; (10) the trocar is adapted to have capability for placing a deflated balloon and such a balloon when inflated can provide distension of the tissues so the nerves and the blood vessels can be easily visualized; (11) the endoscope also includes a anesthesia port for administering an anesthetic agent after proper placement of the endoscope; and (12) the endoscope includes a side port with a distal opening that can be used to inject the local anesthetic and placing a perineural catheter 
         [0026]    The endoscope of this invention combines direct vision and a stimulating electrode like the stimulating needle to improve the efficacy of performing peripheral nerve blocks. In certain embodiment, the endoscope will have a bullet tip so it is atraumatic. The endoscope is adapted to permit visualization for proper electrode placement and stimulation under direct vision of the distally disposed electrode of the endoscope. With an appropriate response the nerve can be anesthetized by injection of a minimum amount of a local anesthetic under direct vision to produce the nerve block. 
         [0027]    The endoscopes of this invention will also have other applications including, without limitation: (1) perineural catheter placement to reduce failed blocks and to permit pain control; (2) blood vessels will be visible, especially central veins. These can be cannulated under direct vision and help prevent complications like arterial punctures and pneumothorax etc. It can help in doing some interventional pain procedures under direct vision and help minimize exposure to X-ray radiation as these presently are done under fluoroscopic guidance (Endoscopes can also be used for surgery performed under the skin or muscles as well as the repair of the peripheral nerves); (3) the endoscopes can include distension of tissues using gas like carbon dioxide at low pressures of about 1 to about 8 mm Hg or other fluid. The tissue distension can also be accomplished using a balloon. 
         [0028]    The peripheral nerve blocks at present are mostly done by placing percutaneous stimulating needles percutaneously based on the anatomic knowledge of the location of the nerves. Some institutions now use ultrasound guidance for performing peripheral nerve blocks. This requires the use of ultrasound gel and lack of it or improper contact with it makes it hard to visualize the nerves. So direct vision would be a great advantage and would greatly facilitate efficient and effective nerve blocking. Although endoscopes are available, none have been used for this technique. The endoscope having a stimulating electrode will allow us to locate the nerve, stimulate the nerve and anesthetize the nerve all under direct visual control. Such a method will also allow us to deal with variations in anatomy. Some times rescue blocks are necessary to have complete anesthesia. This endoscopic method will allow the anesthesiologist to perform such rescue blocks expeditiously. On an average at University of Texas Medical Branch in Galveston, TS, we perform between 50 and 100 peripheral nerve blocks for regional anesthesia per month. We perform between 80 and 100 pain blocks per month and more than 40-60 ventral vein cannulations per month. 
         [0029]    Anesthesiologists do the peripheral blocks and place central venous lines. Interventional pain physicians perform interventional pain procedures under fluoroscopic guidance. Anesthesiologists, internists, surgeons and critical care physicians place the central venous catheters. Versatility of the endoscope and user friendly features will allow for accurate placement of the stimulating catheter or needle for vascular puncture. 
         [0030]    Nerve blocks are performed for surgical anesthesia and postoperative analgesia. The endoscopic method with a stimulating electrode will allow one to localize the nerve under direct visual control and anaesthetize the chosen nerve. This can improve the accuracy of placement of the nerve block and decrease the chances of nerve damage. It will also decrease the time it takes to do the nerve block. The volume of local anesthetic required to produce anesthesia or analgesia of that nerve will be much less as it is placed directly on the target and this also decreases the chances of producing local anesthetic toxicity. In certain embodiments, the endoscope will have a bullet tip so it minimizes the chances of causing damage to the nerves and prevents the inadvertent puncture of a blood vessel, which could lead to systemic toxicity to other organs in the body. 
         [0000]    Endoscopes of this Invention 
         [0031]    Referring now to  FIGS. 1A&amp;B , an embodiment of an apparatus of this invention, generally  100 , is shown to include a body  102  having a proximal end  104  and a distal end  106 . The apparatus  100  also includes a light delivery assembly  108  having two light delivery conduits  110  and a light receiving conduit  112 , where the light delivery assembly  108  is connected to a light source (not shown) at its proximal end  114  and where the conduits  110  terminate in the distal end  106  of the body  102 . Light exiting distal ends  116  of the conduits  110  are used to illuminate tissue as the endoscope  100  is inserted into a site of an animal including a human and a portion of the reflected light is received by a distal end  113  of the receiving conduit  112 , where it can be directly viewed and/or travels to an image processing and display unit not shown. The apparatus  100  also includes a fluid conduit  118  terminating in an exit port  120  near a distal end  106  of the body  102 . A proximal end  122  of the fluid conduit  118  is optionally fitted with a Y-connector  123  so that the type of fluid introduced into the fluid conduit  118  can be changed or a fluid, especially a gas, can be introduced to dilate the tissue so that the tissue can be visualized easily. The apparatus  100  also includes a ring shaped stimulating electrode  124  connected via a conducting conduit  125  to a nerve stimulator  126  having a second conducting conduit  127  including a second electrode  128  adapted to be placed on the skin to act as ground and to produce a voltage at the ring electrode  124 . The electrode  124  can be composed of any conductor and can be of any size. In certain embodiments, the electrode  124  is a thin metal foil. Generally, the light delivery and receiving conduits comprises one or a plurality of optical fibers or optical fiber bundles. In certain embodiment, the light delivery and receiving conduits are a single fiber or microfiber. 
         [0032]    For further details on the type of endoscopes that can be equipped with an electrode new block stimulator of this invention include at least the endoscopes disclosed in U.S. Pat. Nos. 7,150,752, 7,134,993, 6,793,622, 6,702,737, 6,699,183, 6,673,060, 6,641,528, 6,595,982, 6,522,933, 6,491,627, 6,482,148, 6,398,776, 6,236,876, 6,203,494, 6,030,360, 6,013,024, 5,960,145, 5,938,588, 5,916,147, 5,752,912, 5,681,263, 5,667,476, 5,575,755, 5,531,664, 5,512,035, 5,464,007, 5,448,989, 5,415,158, 5,396,880, 5,386,816, 5,381,782, 5,359,994, 5,347,989, 5,325,845, 5,301,656, 5,299,559, 5,176,126, 5,167,221, 5,005,558, 4,996,974, 4,967,732, 4,947,827, 4,941,454, 4,834,069, 4,796,607, 4,790,294, 4,787,369, 4,773,395, 4,762,119, 4,762,118, 4,750,477, 4,700,693, 4,688,555, 4,557,254, 4,499,895, 4,483,326, 4,432,349, 4,351,323, 4,294,233, and 4,203,430, incorporated herein by reference. 
         [0033]    Referring now to  FIGS. 1C-E , an embodiment of an apparatus of this invention, generally  140 , is shown to include a body  142  having a proximal end  144  and a distal end  146 . The apparatus  140  also includes a light delivery assembly  148  having two light delivery conduits  150  and a light receiving conduit  152 , where the light delivery assembly  148  is connected to a light source (not shown) at its proximal end  154  and where the conduits  150  terminate in the distal end  146  of the body  142 . Light exiting distal ends  156  of the conduits  150  is used to illuminate tissue as the endoscope is inserted into a site of an animal including a human and a portion of the reflected light is received by a distal end  153  the receiving conduit  152 , where it travels to an image processing and display unit not shown. The apparatus  140  also includes a fluid conduit  158  terminating in a exit port  160  near a distal end  146  of the body  142 . A proximal end  162  of the fluid conduit  158  is fitted with a Y-connector  163  so that the type of fluid introduced into the fluid conduit  158  can be changed or to use the fluid conduit to inject a component such as a gas to dilate the tissue. The apparatus  140  also includes a two element stimulating electrode  164  having two elements  165  connected via conducting conduits  166  to a nerve stimulator  167  having a second conducting conduit  168  including a second electrode  169  adapted to be placed on the skin to produce a voltage at the ring electrode  164  as shown in  FIG. 1D . Looking at  FIG. 1E , a second element stimulating electrode  164  is shown having four stimulating elements  165 . 
         [0034]    Referring now to  FIGS. 1F&amp;G , an embodiment of an apparatus of this invention, generally  170 , is shown to include a body  172  having a proximal end  174  and a distal end  176 . The apparatus  170  also includes a light delivery assembly  178  having two light delivery conduits  180  and a light receiving conduit  182 , where the light delivery assembly  178  is connected to a light source (not shown) at its proximal end  184  and where the delivery conduits  180  terminate in the distal end  176  of the body  172 . Light exiting distal ends  186  of the conduits  180  is used to illuminate tissue as the endoscope is inserted into a site of an animal including a human and a portion of the reflected light is received by a distal end  183  the receiving conduit  182 , where it travels to an image processing and display unit not shown. The apparatus  170  also includes a fluid conduit  188  terminating in a exit port  190  near a distal end  176  of the body  172 . A proximal end  192  of the fluid conduit  188  is fitted with a Y-connector  193  so that the type of fluid introduced into the fluid conduit  188  can be changed or to use the fluid conduit to withdraw fluids from the site. The apparatus  100  also includes a ring shaped mesh stimulating electrode  194  connected via a conducting conduit  195  to a nerve stimulator  196  having a second conducting conduit  197  including a second electrode  198  adapted to be placed on the skin to produce a voltage at the mesh electrode  194 . 
         [0035]    Referring now to  FIGS. 2A-C , an embodiment of an apparatus of this invention, generally  200 , is shown to include a body  202  having a proximal end  204  and a distal end  206 . The apparatus  200  also includes a single optical fiber  208  adapted to deliver incident light to and receive reflected light from a tissue site into which the body  202  is inserted. Light exits through a distal end  210  of the fiber  208  and illuminates tissue as the endoscope  200  is inserted into a site of an animal including a human. A portion of incident light is reflected back into fiber  208  for subsequence analysis and conversion into an image with a light analyzing and image viewing unit  212 . The apparatus  200  also includes a fluid conduit  214  terminating in an exit port  216  near the distal end  206  of the body  202 . A proximal end  218  of the fluid conduit  214  is optionally fitted with a Y-connector  220  so that the type of fluid introduced into the fluid conduit  218  can be changed or a fluid, especially a gas, can be introduced to dilate the tissue so that the tissue can be visualized easily. 
         [0036]    The apparatus  200  also includes an electrode housing  222  having a proximal end  224  and a distal end  226 . Threaded through the housing  222  is a conducting member  228 . The conducting member  228  includes an electrode  230  at its distal end  232  and is connected to an electrode extension and retraction unit  234  at its proximal end  236 . The electrode extension and retraction unit  234  is adapted to shield the electrode  230  during endoscope  200  insertion and to extend the electrode  230  once the distal end  206  is positioned adjacent a nerve to be stimulated. The extension and retraction unit  234  is connected via a conducting conduit  238  to a nerve stimulator  240  having a second conducting conduit  242  including a second electrode  244  adapted to be placed on the skin to act as ground and to produce a volt difference across the electrodes  230  and  244 . 
         [0037]    Once the distal end  206  of the endoscope  200  is positioned relying on images or direct views through the fiber  208 , the electrode  230  is extended and voltage is applied across the electrode  230  and  244  to stimulate the nerve. If the correct nerve is stimulated evidenced by flex action, then the electrode  230  can be retracted and anesthesia introduced to the site via the fluid conduit  214 . The electrodes  230  and  244  and the conducting member can be composed of any conductor and can be of any size. The extension and retraction unit  234  can be a manual device or an electromechanical device that is adapted to push and pull the electrode  230  so that it can be extended or retracted. 
         [0000]    Method for Using the Endoscopes of this Invention 
         [0038]    Scenario No. 1 
         [0039]    Referring now to  FIGS. 3A-F , an embodiment of the method of this invention is shown. Looking at  FIG. 3A , the method includes the step of inserting a needle  300  carrying a catheter  302  such as an angiocath through a skin  304  at a tissue site  306  of an animal including a human. Once properly placed, the needle  300  in removed and a guide wire  308  is threaded through the catheter  302  as shown in  FIG. 3B . Next, the catheter  302  is removed and a dilator  310  is placed over the wire  308  and pushed into the site  306  to distend the tissue as shown in  FIG. 3C . After distending the tissue using the dilator  310 , a trocar  312  having a balloon  314  is placed over the dilator  310  and pushed into place to further distend the tissue as shown in  FIG. 3D . The guide wire  308  and dilator  310  are then removed leaving the trocar  312  behind and the balloon  314  is inflated to further distend the tissue as shown in  FIG. 3E . Next, an endoscope or a fiberoscope of this invention  100  including a ring electrode  124  is inserted through the trocar  312  to provide the ability of directly or through a monitor to visualize the structures and to permit proper positioning of the electrode on the endoscope as shown in  FIG. 3F . 
         [0040]    Scenario No. 2 
         [0041]    Referring now to  FIGS. 4A-e , an embodiment of the method of this invention is shown. Looking at  FIG. 4A , the method includes the step of inserting a needle  400  carrying a catheter  402  such as an angiocath through a skin at a site  404  of a tissue  406  of an animal including an human. Once properly placed, the needle  400  in removed and a guide wire  408  is threaded through the catheter  402  as shown in  FIG. 4B . Next, the catheter  402  is removed and a dilator  410  is placed over the wire  408  and pushed into the tissue  406  to distend the tissue as shown in  FIG. 4C . After distending the tissue using the dilator  410 , a trocar  412  having a side port  414  is placed over the guide wire  408  and pushed into place as shown in  FIG. 4D . Carbon dioxide is then insufflated at a pressure between about 4 and about 8 mm Hg through the side port  414  to distend the tissue. Next, the dilator  410  is removed and an endoscope or a fiberoscope of this invention  416  is inserted through the trocar  412  to visualize the structures and to permit proper positioning of the electrode on the endoscope as shown in  FIG. 4E . 
         [0042]    Scenario No. 3 
         [0043]    Referring now to  FIGS. 5A-E , an embodiment of the method of this invention is shown. Looking at  FIG. 5A , the method includes the step of inserting a needle  500  carrying a catheter  502  such as an angiocath through a skin at a tissue site  504  of a tissue  506  of an animal including an human. Once properly placed, the needle  500  in removed and a guide wire  508  is threaded through the catheter  502  as shown in  FIG. 5B . Next, the catheter  502  is removed and a dilator  510  is placed over the wire  508  and pushed into the tissue  506  to distend the tissue as shown in  FIG. 5C . After distending the tissue using the dilator  510 , an introducer  512  is passed over the wire  508 , and then a trocar  514  having a side port  516  and a circular balloon  518  is introduced over the introducer  512  into the tissue  506  and insufflate carbon dioxide through the side port  514  using a pressure between about 4 and about 8 mm Hg pressure to create an optical cavity. The balloon  518  is then inflated to further distend the tissue  506 . Next, the wire  508  is then removed and a flexible endoscope of this invention  520  is passed through the trocar  514  and introducer  512  to visualize the structures and to permit proper positioning of the electrode on the endoscope as shown in  FIG. 5E . 
         [0044]    Referring now to  FIG. 6 , an embodiment of the apparatus, generally  600 , is shown positioned adjacent a site  602  of a peripheral nerve  604 . The apparatus  600  is located in a tissue  606  showing an artery  608  and a vein  610  traveling near the nerve  604 . 
         [0045]    All references cited herein are incorporated by reference. Although the invention has been disclosed with reference to its preferred embodiments, from reading this description those of skill in the art may appreciate changes and modification that may be made which do not depart from the scope and spirit of the invention as described above and claimed hereafter.