Abstract:
A snare injection device for performing endoscopic transection procedures is disclosed. The device includes a snare system and a needle system, each containing actuator components separately routed in one of two channels of an elongated dual lumen. Deployment of the snare and needle are independently operated by two separate handle controls. The device includes needle travel stop and anti-puncture features for safety and ease of use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This non-provisional application claims the benefit of U.S. Provisional Patent Application No. 60/574,073, entitled “Snare Injection Device,” filed May 25, 2004, which is hereby incorporated in its entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to an endoscopic medical device and more particularly to a snare injection device for performing endoscopic transection procedures. 
   BACKGROUND OF THE INVENTION 
   Endoscopes are well-known in the art and are commonly used for numerous medical procedures. One such procedure is removing polyps, lesions or other types of targeted tissue from the gastrointestinal mucosal wall of a human subject. 
   Several drawbacks exist with conventional polypectomy removal techniques. Various cauterization devices have been developed to remove polyps. However, these devices sometimes cause serious thermal injury to the gastrointestinal wall, fail to remove the entire targeted tissue, or do not completely cauterize blood vessels which lead to excessive bleeding. Snare devices designed to encircle and remove polyps may not capture all the targeted tissue. Further, a physician may experience difficulty in securing the targeted tissue with the snare. Snaring only the minimal tissue required from the three layer wall, i.e., mucosa, submucosa, and muscularis, is also important. More specifically, to prevent complications, the muscularis tissue should be avoided in this type of procedure. In an effort to solve these and other problems, one technique used is sub-mucosal lift polypectomy which involves injecting the tissue with, for example a saline solution, to lift the tissue to a more favorable position. This technique improves complete transection. The injected fluid separation also insulates the outer muscle from cautery or thermal injury. 
   Various other procedures require a needle and a snare, including use of a needle to wash the site, applying dies for the purpose of highlighting diseased or abnormal tissue, for injecting tattoo medium for post-transection surveillance purposes, and hemostatic injection therapy for post-polypectomy bleeding. In these and other procedures requiring a snare and a needle, a physician must use two separate auxiliary instruments, and one at a time feed them in and out of the instrument channel, which increases the overall procedure time. Therefore, a need exists in the art for a snare injection device that offers an improvement over prior art designs. 
   The present invention is a device that includes a snare and a needle, each separately routed in one channel of a dual channel lumen. The needle may perform several functions during the procedure, including pre-procedure and post-procedure injections, and lifting the tissue during the procedure. The present invention also allows for immediate repeat injections which may be required due to absorption of the lift fluid by the gastrointestinal wall, without removal of the snare. 
   The present invention offers numerous other improvements over prior art needle devices including a needle limit mechanism, consistent 1:1 handle/needle axial movement in a variety of endoscope configurations, and puncture prevention features. In certain prior art designs, a needle could injure a patient by puncturing the sidewall of a device or deploying beyond a desired length to cause harm to a patient. As such, the present invention offers improvements in patient safety and ease of use for the physician. 
   SUMMARY OF THE INVENTION 
   In several illustrated embodiments of the present invention, a snare injection device for performing endoscopic polypectomy procedures is disclosed. It should be apparent to others with ordinary skill in the art that use of this device is not limited to polyp removals, but may also be used with other procedures, such as endoscopic mucosal resections (EMR), adherent blood clot removal, or any other purpose requiring transection and/or injections. 
   In an embodiment of the present invention, a device includes a dual lumen having a first and second channel, a fluid delivery system, and a snare system. The fluid delivery system includes a hollow base, an actuator inserted through the base and the first channel, a hollow knob fixed to the actuator tube proximal end, and a needle fixed to the actuator tube distal end. The snare system includes a body connected to the base, a handle mounted to and movable relative to the body, a cable having a proximal end fixed to the handle that extends substantially through the second channel, and a snare fixed to the cable distal end. 
   Further features and advantages of the invention will become apparent from the following detailed description made with reference to the accompanying drawings. 
   The Detailed Description of the Invention merely describes preferred embodiments of the invention and is not intended to limit the scope of the claims in any way. Indeed, the invention as described by the claims is broader than and unlimited by the preferred embodiments, and the terms in the claims have their full ordinary meaning. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a snare injection device constructed in accordance with one embodiment of the present invention, showing the snare deployed; 
       FIG. 2  is an enlarged perspective view of the distal end of the device of  FIG. 1 , showing the snare and needle deployed; 
       FIG. 3  is a cross-sectional view of the distal end of the device of  FIG. 1 , showing the snare and needle in a stored position; 
       FIG. 4  is a cross-sectional view of the distal end of the device of  FIG. 1 , showing the snare and needle in a deployed position; and 
       FIG. 5  is an enlarged sectional view of the distal end of the device of  FIG. 1 , shown along the lines  5 - 5  in  FIG. 4 . 
   

   DESCRIPTION OF THE INVENTION 
   A snare injection device for performing endoscopic transection procedures is disclosed. The snare and needle are individually routed within a lumen of a dual lumen member. The needle and snare are independently deployable by manipulation of separate control handles by one or two medical operators. 
   In discussing the device, the terms distal and proximal are used with respect to the operator&#39;s hand. In other words, when the device is used within the auxiliary channel of an endoscope or similar device, the proximal and distal orientation are relative to the surgeon or operator of the device. 
   Referring now to the Figures, a snare injection device  10  for use with an endoscope is illustrated in  FIG. 1 . The device is suitable for use in polypectomy procedures and any other procedure in which injection and snare capability is required. In  FIG. 1 , the snare is shown in an expanded position.  FIG. 2  is an enlarged perspective view of the distal end of the device  10 , showing the snare  60  expanded and the needle  36  deployed. The device allows a physician to perform either technique without removing the device from the instrument channel. 
   The device includes an elongated dual lumen  12 . The dual lumen has a first channel  14  and a second channel  16 , each channel leading from a proximal end  18  to a distal end  20 . The lumen  12  shown in a single piece of extruded plastic. The lumen  12  may be constructed from a variety of flexible materials, such as for example, polytetrafluorethylene (PTFE) or polyethylene tubing. Various first and second channel sizes and shapes may be used in the practice of the present invention. Further, it should be apparent to one with ordinary skill in the art that the present invention may be practiced with a single piece of extruded dual lumen tubing, or alternatively, with a dual lumen assembly including separate tubing and a sheath or other suitable covering. 
   A fluid delivery system for use to inject tissue within the body is part of the device  10 . The delivery system includes a hollow base  30  fixed to a proximal end  18  of the lumen  12 . The base  30  provides support for an actuator tube  32  that is threaded through the base and can be moved relative thereto. The tube  32  has a proximal end  33   a  and a distal end  33   b . As shown, the tube  32  is inserted through the base  30  and the first channel  14 . 
   The base  30  further includes a side entry port  38 . As shown, this port  38  is angled less than 45 degrees with respect to a longitudinal axis of the base  30 . It is believed this angled structure reduces binding within the dual lumen  12 . The resulting y-shaped base may be a single molded piece or a two part assembled piece. 
   The actuator tube  32  can be manipulated by movement of a hollow knob  34 . The knob  34  is fixed to said actuator tube  32  proximal end  33   a . A needle  36  is illustrated fixed to the actuator tube  32  distal end  33   b . In this position, a fluid solution can be passed under pressure through the knob to the needle. 
   Referring now to  FIGS. 3 and 4 , a range of motion of the needle  36  is illustrated.  FIG. 3  is a cross-sectional view of the distal end of the  10  device, showing the needle  36  in a stored position. In this at rest position, no axial forces are on the needle  36 . The needle is disposed within a needle housing member  70 . The housing shown is an elongated barb fitting  70  with a hollow interior and a threaded, notched, or intermittedly tapered exterior surface, or otherwise generally relieved body, which offers improved flexibility. Other fittings may be used that are known in the art. Consequently, the needle cannot puncture the sidewalls of the lumen  12  in a stored position. 
   Adjacent to distal end  20  of the dual lumen, the barb  70  may be disposed in place by being heat shrunk, press fit, bonded, or other suitable known method. The barb may be constructed from any coated metal or non-conductive suitable material, such as for example, a medium hardness plastic. It is important that the barb be non-conductive so that radio frequency energy used to energize the snare does not transfer to the barb which in turn would direct the current away from the targeted tissue. The barb may include two or more pieces joined together. 
   After visual identification of targeted tissue, a physician protrudes the needle into the tissue and injects a fluid. A needle  36  in a protruded position is shown in  FIG. 4 . The actuation step to protrude the needle  36  is manipulation of the knob  34  in a direction of the needle  36 . The knob  34 , actuator tube  32  and needle  36  all move axially in a 1:1 distance relationship. The distance L 1  the needle protrudes is pre-determined by a needle stop  37  interfering with a narrowed portion  71  of the barb  70 . The distance L 1  is determined by performance and safety criteria, and can vary in the practice of the present invention. 
     FIG. 4  shows the needle stop  37  shoulder contiguous with the narrow portion  71  in a fully protruded position. The stop  37  and narrowed portion  71  prevent the needle from falling off into the patient if the needle would ever disconnect with the actuator tube  32 . 
   The relationship of the tube  32  and the base  30  is configured to have additional stroke length to overcome any articulate friction or loss motion in the elongated lumen  12  so that full needle projection will occur. After the knob  34  is released, a spring mechanism (not shown) disposed internally in the base  30  forces the knob  34  and needle  36  to return to their at rest position as shown in  FIG. 1 . 
   A snare system for transecting tissue is included in the device  10 . The snare system can be used to remove tissue, such as for example, a polyp after it has been lifted by the injection of a fluid. The snare  60  is shown in a collapsed position in  FIG. 3 . 
   The system includes an elongated body  40  having a thumb ring  42  at a proximal end. A handle  50  is formed on the body  40  as a separate piece. The handle is slidable relative to the body in either a distal or proximal direction by manipulation of two finger rings  52 . The base  40  and handle  50  are formed of a rigid plastic material, although any suitable material may be used in the practice of the present invention. 
   The snare system  10  includes a cable  54  that extends substantially through the second channel  16  of the dual lumen  12 . The cable  54  has a proximal end  55   a  fixed to the handle  42  and a distal end  55   b  fixed to a connector  68 . As shown, the cable  50  further passes through a flexible tube  44  the remotely connects the body  40  to the inlet port  38 . The tube  44  can be constructed from any flexible durable material such as polyethylene. 
     FIGS. 2 and 4  show the snare  60  in an expanded position. The snare  60  is fixed to the distal end of the cable  54  by a connector  68 . The snare  60  is formed by a wire loop having two ends  62  and  64 , as best seen in  FIGS. 4 and 5 . An enlarged sectional view of the distal end of the device  10  is shown in  FIG. 5 . To prevent the wires from crossing and kinking which causes excessive friction and binding of the cable mechanism, a length L 2  of the wires is bound by heat shrink material  66 . This feature also allows for the connector  68  to be positioned more proximately inside the second channel  16  so it will not exit the tube  12  distal end  20 . This proximal position prevents any chance of the connector  68  exiting the tube  12  and catching upon the distal end  20  upon reentry inside the second channel  16 . 
   A series of lumen expanding spacers  80  are illustrated in  FIGS. 3 and 4  in the first channel  14 . The spaces may be press fit, glued, heat inserted or any other suitable method. A total of five equally spaced and sized spacers are shown for exemplary purposes only, although the number, size and spacing of the spacers  80  may vary in the practice of the present invention. The most distal spacer is position axially at the end of the barb  70 . To provide enough space for the needle mechanism to function, the barb  70  occupies over half of the diameter of the distal end portion. As a result, the barb causes sagging of the center membrane that separates the first  14  and second channel  16  at the distal portion of the tube. The spacers  80  effectively provide an extension of the sagging of the first channel  14  for a length L 3  as shown. 
   The extension of the sagging portion provides additional length for travel of the snare loop. In particular, the section of the unsupported wires  62 ,  64 , i.e., the section uncovered by heat shrink  66 , can shift up or down within the second channel  16 . The shifting of the wires does not readily transition through the shifting transition area  90  of the center membrane. So therefore, the spacers  80  provide additional length of the reduced lumen so the unsupported wires  62 ,  64  does not reach the transition area. 
   It should be understood by others with ordinary skill in the art that the length L 3  can vary in the practice of the present invention, as can the positioning of the spacers relative to the heat shrink  66 , the connector  68 , the tube distal end  20 , or other components of the device  10 . 
   While several embodiments of the invention has been illustrated and described, the present invention is not to be considered limited to the precise constructions disclosed. Various adaptations, modifications and uses of the invention may occur to those skilled in the arts to which the invention relates. It is the intention to cover all such adaptations, modifications and uses falling within the scope or spirit of the annexed claims.