Abstract:
An apparatus for the transoral invagination and fundoplication of the stomach to the esophagus includes a clip applier having sharp toothed jaws for grasping and damaging the fundus prior to applying the clip. The clip applier has an overall diameter of less than 7 mm. The clip applier jaws are coupled to a pull wire via a linkage which increases the mechanical advantage and thus permits greater grasping force. A plurality of clip designs are also provided.

Description:
This application is related to co-owned application Ser. No. 10/010,908, filed simultaneously herewith, entitled “Flexible Surgical Clip Applier” the complete disclosure of which is hereby incorporated by reference herein. 
   This application is a continuation-in-part of application Ser. No. 09/931,528, filed Aug. 16, 2001, entitled “Methods and Apparatus for Delivering a Medical Instrument Over an Endoscope while the Endoscope is in a Body Lumen”, the complete disclosure of which is hereby incorporated by reference herein. 
   This application is also a continuation-in-part of application Ser. No. 09/891,775, filed Jun. 25, 2001, entitled “Surgical Clip”, the complete disclosure of which is hereby incorporated by reference herein. 
   This application also claims the benefit of provisional application Ser. No. 60/292,419, filed May 21, 2001, entitled “Methods and Apparatus for On-Endoscope Instruments Having End Effectors and Combinations of On-Endoscope and Through-Endoscope Instruments”. 
   This application is also a continuation-in-part of application Ser. No. 09/730,911, filed Dec. 6, 2000, entitled “Methods and Apparatus for the Treatment of Gastric Ulcers”, the complete disclosure of which is hereby incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to endoscopic surgical instruments. More particularly, the invention relates to flexible instruments for the transoral invagination and fundoplication of the stomach to the esophagus. 
   2. State of the Art 
   Gastroesophageal fundoplication is a procedure for the treatment of gastroesophageal reflux disease (GERD), a condition in which gastric acids are regurgitated into the esophagus resulting in one or more of esophagitis, intractable vomiting, asthma, and aspiration pneumonia. The fundoplication procedure involves wrapping the fundus of the stomach around the lower end of the esophagus and fastening it in place. Traditionally, this procedure is accomplished via open surgery with the use of sutures to secure the plicated fundus of the stomach around the esophagus without penetrating (incising) the stomach. Although traditional fundoplication involves plicating the fundus and the esophagus, as used herein the term includes plicating the fundus to itself near the esophagus. 
   U.S. Pat. No. 5,403,326 to Harrison et al. discloses a method of performing endoscopic fundoplication using surgical staples or two-part surgical fasteners. The procedure disclosed by Harrison et al. involves performing two percutaneous endoscopic gastrotomies (incisions through the skin into the stomach) and the installation of two ports through which a stapler, an endoscope, and an esophageal manipulator (invagination device) are inserted. Under view of the endoscope, the esophageal manipulator is used to pull the interior of the esophagus into the stomach. When the esophagus is in position, with the fundus of the stomach plicated, the stapler is moved into position around the lower end of the esophagus and the plicated fundus is stapled to the esophagus. The process is repeated at different axial and rotary positions until the desired fundoplication is achieved. While, the procedure disclosed by Harrison et al. is a vast improvement over open surgery, it is still relatively invasive requiring two incisions through the stomach. 
   U.S. Pat. No. 5,571,116 to Bolanos et al. discloses a non-invasive treatment of gastroesophageal reflux disease which utilizes a remotely operable invagination device and a remotely operable surgical stapler, both of which are inserted transorally through the esophagus. According to the methods disclosed by Bolanos et al., the invagination device is inserted first and is used to clamp the gastroesophageal junction. The device is then moved distally, pulling the clamped gastroesophageal junction into the stomach, thereby invaginating the junction and involuting the surrounding fundic wall. The stapler is then inserted transorally and delivered to the invaginated junction where it is used to staple the fundic wall. 
   Bolanos et al. disclose several different invagination devices and several different staplers. Generally, each of the staplers disclosed by Bolanos et al. has an elongate body and a spring biased anvil which is rotatable approximately 15 degrees away from the body in order to locate the invaginated gastroesophageal junction between the body and the anvil. The body contains a staple cartridge holding a plurality of staples, and a staple firing knife. Each of the invagination devices disclosed by Bolanos et al. has a jaw member which is rotatable at least 45 degrees and in some cases more than 90 degrees to an open position for grasping the gastroesophageal junction. One of the chief disadvantages of the methods and apparatus disclosed by Bolanos et al. is that the stapler and the invagination device must both be present in the esophagus at the same time. With some of the embodiments disclosed, the presence of both instruments is significantly challenged by the size of the esophagus. In addition, the actuating mechanism of the device disclosed by Bolanos et al. is awkward. In particular, the stapler anvil is biased to the open position, and it is not clear whether or not the stapler anvil can be locked in a closed position without continuously holding down a lever. In addition, it appears that the staple firing trigger can be inadvertently operated before the anvil is in the closed position. This would result in inadvertent ejection of staples into the stomach or the esophagus of the patient. 
   U.S. Pat. No. 6,086,600 to Kortenbach discloses an endoscopic surgical instrument including a flexible tube, a grasping and fastening end effector coupled to the distal end of the tube, and a manual actuator coupled to the proximal end of the tube. The manual actuator is coupled to the end effector by a plurality of flexible cables which extend through the tube. The tube contains a lumen for receiving a manipulable endoscope and the end effector includes a passage for the distal end of the endoscope. The end effector has a store for a plurality of male fastener parts, a store for a plurality of female fastener parts, a rotatable grasper, a rotatable fastener head for aligning a female fastener part and a male fastener part with tissues therebetween, and a firing member for pressing a male fastener part through tissues grasped by the grasper and into a female fastener part. According to a stated preferred embodiment, the overall diameters of the flexible tube and the end effector (when rotated to the open position) do not exceed approximately 20 mm so that the instrument may be delivered transorally to the fundus of the stomach. 
   While transoral invagination and fundoplication apparatus and procedures have improved over the years, it is still difficult to deliver and manipulate the necessary apparatus transorally. The primary reason for the difficulty is that the overall diameter, or more accurately the cross sectional area, of the equipment is too large. Notwithstanding Kortenbach&#39;s reference to 20 mm, most of the equipment in use today is at least 24 mm in diameter. Moreover, even if the equipment could be reduced to 20 mm in diameter (314 mm 2  cross sectional area), it would still be difficult to manipulate. Those skilled in the art will appreciate that larger instruments are less pliable and that the invagination and fundoplication procedure requires that the instruments turn nearly 180 degrees. Moreover, it will be appreciated that large instruments obscure the endoscopic view of the surgical site. 
   Still other issues which need to be addressed in this procedure include the need to suitably grasp the fundus before plication so that all layers of the fundus are plicated. Preferably, plication damages the fundus so that adhesion occurs during healing. 
   3. Co-owned Technology 
   Previously incorporated application Ser. No. 09/730,911, filed Dec. 6, 2000, entitled “Methods and Apparatus for the Treatment of Gastric Ulcers”, discloses a surgical tool which is delivered to a surgical site over an endoscope rather than through the working lumen of an endoscope. 
   Co-owned provisional application Ser. No. 60/292,419, filed May 21, 2001, entitled “Methods and Apparatus for On-Endoscope Instruments Having End Effectors and Combinations of On-Endoscope and Through-Endoscope Instruments”, discloses many tools and procedures including an on-scope grasper assembly having grasping jaws, and a through-scope clip applier having jaws adapted to close about tissue and apply a clip over and/or through the tissue. In operation, the grasper jaws may grab and hold tissue, e.g., the fundus of the stomach or esophageal tissue, while the jaws of the clip applier surround a portion of the tissue held by the grasper jaws and apply a clip thereover. 
   Previously incorporated application Ser. No. 09/891,775, filed Jun. 25, 2001, entitled “Surgical Clip”, discloses a surgical clip having a U-shaped configuration with first and second arms, and a bridge portion therebetween. The first arm is provided with a tip preferably having a catch, and the second arm extends into a deformable retainer having a tissue-piercing end and preferably also a hook. During application, tissue is clamped, and the clip is forced over the clamped tissue and the retainer of the second arm is bent and may be pierced through the tissue. The retainer is toward and around or adjacent the tip of the first arm preferably until the hook is engaged about the catch to secure the clip to the tissue and prevent the clip and tissue from separating. The clip is provided with structure that facilitates the stacking of a plurality of clips in a clip chamber of a clip applier. 
   Previously incorporated application Ser. No. 09/931,528, filed Aug. 16, 2001, entitled “Methods and Apparatus for Delivering a Medical Instrument Over an Endoscope while the Endoscope is in a Body Lumen”, discloses methods and apparatus for delivering a medical instrument over the exterior of an endoscope while the endoscope is installed in the patient&#39;s body in order to allow the use of instruments which are too large to fit through the lumina of an endoscope. 
   The previously incorporated simultaneously filed application entitled “Flexible Surgical Clip Applier”, discloses a surgical clip applier having a pair of clip applying jaws at the distal end of an outer coil, a set of pull wires extending through the outer coil and coupled to the jaws, and a push wire extending through the outer coil. A clip chamber is provided in the distal end of the coil. A clip pusher is provided at a distal end of the push wire, and adapted to advance a clip into the jaws. The jaws include clamping surfaces which operate to compress tissue between the jaws when the jaws are closed, channels in which a distal most clip rides when the jaws are closed and the pusher is advanced thereby causing the distal most clip to be pushed over the tissue, and distal anvil portions which operate to bend a portion of the distal most clip to facilitate its retention on the clamped tissue. The clip applier is capable of providing a pushing force far in excess of a perceived possible maximum of the 200 grams (0.44 lbs) published in the art. One embodiment of the device of the invention provides a pushing force in excess of 2267 grams (5 lbs). 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the invention to provide methods and apparatus for transoral invagination and fundoplication. 
   It is also an object of the invention to provide an apparatus for transoral invagination and fundoplication which is easy to manipulate. 
   It is another object of the invention to provide an apparatus for transoral invagination and fundoplication which has a relatively small cross-sectional area. 
   It is still another object of the invention to provide methods and apparatus for fundoplication which combine the relative advantages of staples and two-part fasteners, i.e. the small size of a staple and the greater integrity of a two-part fastener. 
   It is yet another object of the invention to provide methods and apparatus for transoral invagination and fundoplication which damages tissue such that adhesion occurs during healing. 
   In accord with these objects which will be discussed in detail below, the methods of the invention include delivering a grasper, a clip applier, and an endoscope transorally to the site of fundoplication; grasping the fundus with the grasper (or similar device, e.g. corkscrew) and pulling it into the jaws of the clip applier; closing the jaws of the clip applier over the fundus and applying a clip to the fundus. The method is repeated at different locations until the desired fundoplication is achieved. The apparatus of the invention includes a clip applier having sharp toothed jaws for grasping and damaging the fundus prior to applying the clip. The clip applier has an overall diameter of less than 7 mm and may be delivered through a 7 mm sleeve which attaches to a 12 mm endoscope having a lumen through which the grasper is delivered. The overall cross-sectional area of the apparatus is therefore approximately 152 mm 2  as compared to the 314 mm 2  of the prior art devices. Alternatively, the clip applier and the grasper may be delivered through an endoscope having two 6 mm lumina. 
   According to a presently preferred embodiment, the clip applier jaws are coupled to a pull wire via a linkage which increases the mechanical advantage and thus permits greater grasping force. 
   A plurality of clip designs are provided. Some embodiments include a pair of arms coupled by a bridge and a single locking retainer. Other embodiments include dual parallel coiled retainers. According to one embodiment, the clip has two detachable retainers which are installed in the fundus and the clip arms and bridge are removed. 
   Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a clip applier according to the invention; 
       FIG. 2  is a side elevational view of a first embodiment of the distal end of the clip applier with the jaws in the closed position; 
       FIG. 3  is a side elevational view of a first embodiment of the distal end of the clip applier with the jaws in the open position; 
       FIG. 4  is a broken isometric view of a first embodiment of the distal end of the clip applier with one jaw removed; 
       FIG. 5  is a broken isometric view of a second embodiment of the distal end of the clip applier with a clip of the type shown in  FIGS. 19 and 20 ; 
       FIG. 6  is an isometric view of a single jaw of the second embodiment of the distal end of the clip applier; 
       FIG. 7  is a proximal end view of the jaw of  FIG. 6 ; 
       FIG. 8  is a proximal end view of the two jaws of a second embodiment of the distal end of the clip applier in the closed position with the lower jaw shaded for clarity; 
       FIG. 9  is a broken isometric view of a third embodiment of the distal end of the clip applier suitable for use with a clip of the type shown in  FIGS. 17 and 18  or  24 ; 
       FIGS. 10-14  are schematic views illustrating a method according to the invention; 
       FIG. 15  is a diagram illustrating the comparative cross-section of the instruments used in the method illustrated in  FIGS. 5-10  and a typical prior art instrument; 
       FIG. 16  is a cross-sectional view of a dual lumen endoscope which can be used in performing the methods of the invention; 
       FIG. 17  is a side elevational view of a first embodiment of a clip according to the invention prior to application; 
       FIG. 18  is a side elevational view of the clip of  FIG. 17  after application; 
       FIG. 19  is a side elevational view of a second embodiment of a clip according to the invention prior to application; 
       FIG. 20  is a side elevational view of the clip of  FIG. 19  after application; 
       FIG. 21  is a side elevational view of a third embodiment of a clip according to the invention prior to assembly; 
       FIG. 22  is a side elevational view of the clip of  FIG. 21  assembled prior to application; 
       FIG. 23  is a side elevational view of the applied portion of the clip of  FIGS. 17 and 18 ; 
       FIG. 24  is a view similar to  FIG. 23  of an alternate third embodiment of the applied portion of a clip according to the invention; and 
       FIG. 25  is a fragmentary, cross-sectional enlarged view of a portion of the clip applier of  FIG. 5  with a portion of a clip in an applier groove and through tissue. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to  FIG. 1 , a clip applier  10  according to the invention generally includes a flexible wound outer coil  12  having a proximal end  14  and a distal end  16 . An end effector assembly  18  is coupled to the distal end  16  of the coil  12  and an actuator assembly  20  is coupled to he proximal end  14  of the coil  12 . A plurality of pull/push wires  58 ,  60  (shown and described below with reference to  FIGS. 2-4 ) extend through the coil  12  and couple the end effector assembly  18  to the actuator assembly  20 . The clip applier  10  is similar to the clip applier described in detail in previously incorporated co-owned application Ser. No. 10/010,908, entitled “Flexible Surgical Clip Applier”, filed simultaneously herewith. However, in this application, the end effector assembly  18  is designed specifically for fundoplication using a clip significantly larger than that used in the clip applier of the aforesaid co-owned application. 
     FIGS. 2-4  illustrate the details of the end effector assembly  18  according to a first embodiment of the invention. The end effector assembly  18  includes a pair of jaws  22 ,  24  which are rotatably coupled to a clevis  26 . In particular, the clevis  26  has a central channel  28  (seen best in  FIG. 4 ) which is defined by clevis arms  30 ,  32 . Although the term “clevis” is used because of its general acceptance in the art of endoscopic instruments, the “clevis”  26  is preferably covered on top and bottom so that the only exit from the channel  28  is at the distal end. The jaw  22  is rotatably coupled to the clevis arm  30  by an axle  34  and the jaw  24  is rotatably coupled to the clevis arm  32  by an axle  36 . The axles  34  and  36  are dimensioned such that they do not significantly obscure the channel  28 . 
   The jaws  22 ,  24  are substantially identical. Each jaw  22 ,  24  includes a proximal tang  38 ,  40 , a mounting bore  42 ,  44 , a distal hook shaped anvil  46 ,  48  and a plurality of medial teeth  50 ,  52 . As seen best in  FIG. 4 , the medial teeth  50 ,  52  are arranged on one side of the jaw and a short wall  51 ,  53  is arranged on the opposite side of the jaw to define a groove (or guiding channel)  54 ,  56 . The grooves  54 ,  56  meet the anvils  46 ,  48  each of which which has a helical surface. The interior (proximal) helical surfaces of the anvils act to bend the clip retainers as described below with reference to  FIGS. 19-24 . 
   The proximal tang  38 ,  40  of each jaw is coupled to a respective pull/push wire  58 ,  60  via two links  62 ,  64  and  66 ,  68 . The links  62 ,  66  are substantially L-shaped and are rotatably coupled near their elbow to the clevis arms  30 ,  32  by axles  70 ,  72  which do not significantly obscure the channel  28  between the clevis arms. One end of the link  62 ,  66  is coupled to the pull/push wire  58 ,  60  and the other end of the link  62 ,  66  is rotatably coupled to one end of the link  64 ,  68 . The other end of the link  64 ,  68  is rotatably coupled to the tang  38 ,  40 . The combined coupling of each jaw  22 ,  24  to each pull/push wire  58 ,  60  forms a linkage which amplifies the force from the pull/push wires to the jaws. In particular, as the jaws close, the mechanical advantage increases. 
   The proximal ends of the pull/push wires  58 ,  60  are coupled to the actuator assembly ( 20  in  FIG. 1 ) as described in previously incorporated co-owned application Ser. No. 10/010,908, entitled “Flexible Surgical Clip Applier”, filed simultaneously herewith. 
   A clip pusher (not shown) disposed in the interior of the coil is coupled to a push wire (not shown) which is coupled to the actuator assembly as described in previously incorporated co-owned application Ser. No. 10/010,908, entitled “Flexible Surgical Clip Applier”, filed simultaneously herewith. Unlike the previously incorporated co-owned application, the jaws of the instant clip applier are significantly longer and designed for use with clips approximately 17-20 mm long (after the clip is applied) as compared to the 5-7 mm clips shown in the previously incorporated co-owned application. 
   Turning now to  FIGS. 5-8 , a second embodiment of the jaws  22 ′,  24 ′ is illustrated. The jaws  22 ′,  24 ′ are substantially identical to each other and are designed for use with any of the clips illustrated in  FIGS. 19-24 . Each jaw  22 ′,  24 ′ includes a proximal tang  38 ′,  40 ′, a mounting bore  42 ′,  44 ′, a distal hook shaped anvil  46 ′,  48 ′ and a plurality of medial teeth  50 ′,  52 ′. The medial teeth  50 ′,  52 ′ are arranged on one side of the jaw and a short wall  51 ′,  53 ′ is arranged on the opposite side of the jaw to define a groove (or guiding channel)  54 ′,  56 ′. The grooves  54 ′,  56 ′ meet the interior surfaces of the anvils  46 ′,  48 ′ which curve about a single axis. The interior surfaces of the anvils act to bend the clip retainers as described below with reference to  FIGS. 19-24  and as shown by the clip  310  in FIG.  5 . According to this embodiment, as seen best in  FIGS. 6-8 , the guiding channels  54 ′,  56 ′ and the anvils  46 ′,  48 ′ are angled relative to the vertical axis of the jaw  22 ′,  24 ′. This angle causes the clip to twist as it is pushed through the jaws so that the ends of the clip are offset as shown in  FIG. 5 , for example. According to the presently preferred embodiment, the guiding channels  54 ′,  56 ′ and the anvils  46 ′,  48 ′ are angled approximately 22° relative to the vertical axis of the jaw  22 ′,  24 ′. According to a method of the invention, clips for use with this embodiment of the jaws are prebent in the bridge area to facilitate movement through the angled channels. 
   Referring now to  FIG. 9 , a third embodiment of the jaws  22 ″,  24 ″ is illustrated. The jaws  22 ″,  24 ″ are no identical to each other and are designed for use with clips f the type illustrated in  FIGS. 17-18 . Each jaw  22 ″,  24 ″ includes a proximal tang  38 ″,  40 ″ and a mounting bore  42 ″,  44 ″. One jaw  22 ″ terminates with two spaced apart distal hooks  46 ″,  47 ″ and has two rows of medial teeth  50 ″. The other jaw  24 ″ terminates with a single distal hook shaped anvil  48 ″ and has two rows of medial teeth  52 ″. The medial teeth  50 ″,  52 ″ are arranged on both sides of the jaw and a groove (or guiding channel)  54 ″,  56 ″ lies between the rows of teeth. The groove  54 ″ terminates with an undercut well (not shown) a described in co-owned Ser. No. 10/010,908, whereas the groove  56 ″ continues on to the interior of the any  48 ″ which has a surface which curves about a single axis. Those skilled in the art will appreciate that when the jaws are closed, the anvil  48 ″ will reside between the hooks  46 ″ and  47 ″ and the teeth  50 ″ will be interleaved with the teeth  52 ″. The interior surface of the anvil  48 ″ bends the clip retainer as described below with reference to  FIGS. 17-18  and as shown and described in previously incorporated co-owned applications Ser. No. 09/891,775, and Ser. No. 10/010,908. 
   Turning now to  FIGS. 10-14 , a method of using the clip applier of the invention is illustrated in context with an existing endoscope  100  having a single lumen through which a small grasper  102  is supplied and an external working channel  104  which is attached to the scope  100  and through which the clip applier is delivered. The external working channel  104  is preferably one of the type described in previously incorporated application Ser. No. 09/931,528, filed Aug. 16, 2001, entitled “Methods and Apparatus for Delivering a Medical Instrument Over an Endoscope while the Endoscope is in a Body Lumen”. 
   According to a method of the invention, after the endoscope assembly is delivered transorally to the procedural site, as shown in  FIG. 10 , the fundus is grasped by the graspers and pulled in between the open jaws of the clip applier. The jaws of the clip applier are then closed onto the invaginated fundus as shown in FIG.  11 . As the jaws are closed the medial teeth of the jaws puncture the invaginated fundus as shown in  FIGS. 11 and 12 . When the jaws are completely closed (or closed as much as possible), they are preferably locked, the grasper is optionally released, and the clip pusher is activated to push forward, advance, and/or slide, with or without tissue contact, a clip  106  as shown in FIG.  12  and as described in the previously incorporated, co-owned, simultaneously filed application and discussed in detail hereinafter. 
   After the clip  106  is applied, the jaws of the clip applier are opened as shown in FIG.  13  and the clip  106  remains in place and plicates the fundus. Depending on the location of the clip and the nature of the patient&#39;s condition, a single clip may be sufficient. If other clips are deemed desirable by the practitioner, the clip applier is removed and re-loaded with another clip. After re-delivering the clip applier, the procedure may be repeated at another location as shown in FIG.  14 . Given the size of the clips of the invention, anywhere from 1-4 clips will typically be used. 
   According to one aspect of the invention, the medial teeth on the jaws of the clip applier are long enough and sharp enough to damage the fundus sufficiently such that when the fundus heals adhesion occurs, binding the plicated fundus to the extent that the clip may no longer be needed. Thus, preferably, the teeth are long enough to pierce all layers of the fundus. 
   From the foregoing, those skilled in the art will appreciate that the methods of the invention may be performed with different types of graspers. In particular, alternative grasping devices such as a “cork screw” grasper can be used in conjunction with the clip applier of the invention to perform the methods of the invention. 
   It will also be appreciated that the clip applier of the invention may be attached to an endoscope in other ways as described in previously incorporated application Ser. No. 09/931,528, filed Aug. 16, 2001, entitled “Methods and Apparatus for Delivering a Medical Instrument Over an Endoscope while the Endoscope is in a Body Lumen”. 
   As mentioned above, the clip applier of the invention has an outside diameter of approximately 6 mm. As shown in  FIGS. 10-14 , the clip applier is used in conjunction with an endoscope having an outside diameter of approximately 12 mm. To accommodate the clip applier, an exterior working channel having an exterior diameter of approximately 7 mm is optionally coupled to the endoscope as described in the previously incorporated co-owned applications Ser. Nos. 09/931,528 and 60/292,419. 
     FIG. 15  is a scale representation of the cross-sectional area of the 12 mm endoscope  100  with the attached external 7 mm working channel  104 , shown in horizontal shading. The cross sectional area of a prior art device  108  having an exterior diameter of approximately 24 mm is shown in diagonal shading. From  FIG. 15 , it will be appreciated that the methods and apparatus of the invention allow for a substantially smaller device which is more easily delivered transorally and which is more easily manipulated. The overall cross-sectional area of the apparatus of the invention is approximately 152 mm 2  as compared to the 314 mm 2  of the prior art devices. 
   As mentioned, the clip applier of the invention may also be used with a dual lumen endoscope.  FIG. 16  is a scale representation of a dual lumen endoscope  110  having an optical lumen  112  and two 6 mm working lumina  114 ,  116 . As compared to the device  108  in  FIG. 15 , the endoscope  110  has a substantially smaller cross-sectional area than the prior art device. 
   The clips used by the clip applier of the invention are substantially longer than the clips described in the previously incorporated co-owned applications, Ser. No. 09/891,775 and the simultaneously filed application, which are approximately 7 mm in length and adequate for general surgical applications. The retainer portion of the clips of the present invention are substantially longer in order to assure that all of the layers of the fundus are punctured. 
   Turning now to  FIGS. 17 and 18 , a first embodiment of a surgical clip  210  according to the invention includes first and second arms  212 ,  214 , respectively, and a bridge portion  216  therebetween such that the arms and bridge portion are in a generally U-shaped configuration. The first arm  12  is provided with an end catch  220 , and the second arm  214  extends (or transitions) into a deformable retainer  222  having a tissue piercing tip  224  and a plurality of catch engagements, e.g.  226 ,  228 . The arms define an open space  230  between them. The clip  210  is preferably made from a unitary piece of titanium, titanium alloy, stainless steel, tantalum, platinum, other high Z (substantially radiopaque) materials, nickel-titanium alloy, martensitic alloy, or plastic, although other suitable biocompatible materials may be used. The first and second arms  212 ,  214 , as well as the bridge portion  216  are relatively stiff and not plastically deformable within the limits of force applied to the arms during use, while the retainer  222  is relatively easily plastically deformable by the clip applier. 
   Referring now to  FIGS. 2-4  and  17 - 18 , when the clip  210  is pushed forward in the clip applier with the jaws  22 ,  24  of the clip applier closed, the retainer  222  is bent across the opening  230  between the first and second arms  212 ,  214  and into engagement with the end catch  220  of the first arm  212  as shown in FIG.  18 . The anvil formed by the grooves on the interior of the hooks  46 ,  48  of the clip applier jaws guide the bending of the retainer  222  causing it to puncture the fundus and couple to the end catch  220 . 
   The clip  210  shown in  FIGS. 17 and 18  is provided with an optional bendable barb  232  which provides a secondary stabilizing fixation point which helps keep the clip from rotating. As the clip is pushed forward over the fundus, tissue catches the barb  232  and bends it as shown in FIG.  18 . 
   The clip  210  is also provided with an ear  233  on the bridge  216 . The ear is used by the pushing mechanism (not shown) to grasp the end of the clip when it is loaded into the clip applier. 
   A second embodiment of a clip  310  according to the invention is shown in  FIGS. 19 and 20 . The clip  310  has two arms  312 ,  314  connected by a bridge  316 . Both arms terminate in retainers  320 ,  322 , each having a sharp end  321 ,  323 . The clip  310  is also provided with a pair of ears  333 ,  335  on the bridge  316 . The ears are used by the pushing mechanism (not shown) to grasp the end of the clip when it is loaded into the clip applier. This embodiment is intended for use with a clip applier having hooks with interior grooves which diverge, or which are in parallel planes. With reference to  FIGS. 2-4  and  15 - 16 , when the clip  310  is pushed forward, the retainer  320  is bent by the groove inside the hook  46  and the retainer  322  is bent by the groove inside the hook  48  to the configuration shown in FIG.  20 . From  FIG. 20 , it will be appreciated that each retainer punctures the fundus twice substantially forming a circular fastener. Thus, it will also be appreciated that the retainers  320 ,  322  are significantly longer than the retainer  222  shown in  FIGS. 17 and 18  and preferably are of a length at least π times the distance between the arms  312 ,  314 . Insofar as the retainers  320 ,  322  each form a complete fastener, the function of the arms  312 ,  314  and the bridge  316  may be considered redundant. 
     FIGS. 21-23  illustrate a third embodiment of a clip  410  according to the invention. The clip  410  is similar to the clip  310  (with similar reference numerals increased by  100  referring to similar parts) except that the retainers  420 ,  422  are removable from the arms  412 ,  414 . The arms  412 ,  414  terminate in female couplings  413 ,  415  which receive ends of the retainers  420 ,  422  in a slight interference fit. The clip  410  is also provided with a pair of ears  433 ,  435  on the bridge  416 . The ears are used by the pushing mechanism (not shown) to grasp the end of the clip when it is loaded into the clip applier. The clip  410  is applied to the fundus in substantially the same way as described above with reference to the clip  310 . However, after the retainers  420 ,  422  are bent by the anvils and the jaws are opened, the clip  410  is not released from the clip applier and the retainers are separated from the arms  412 ,  414 . The resulting fastener formed by the retainers  420 ,  422  is shown in FIG.  23 . This is actually two substantially parallel “b” shaped fasteners. Thus, it may only be necessary to apply a single retainer as shown in  FIG. 24 , for example. 
     FIG. 25  illustrates an enlarged portion of the clip applier of  FIG. 5  showing that the clip  310  rests inside an applier groove  54 &#39;,  56 &#39; and is bent by the anvil  48 &#39; as it pierces a folded over portion of body tissue  500 . 
   There have been described and illustrated herein several embodiments of methods and apparatus for the endoluminal treatment of gastroesophageal reflux disease. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.