referring now to fig1 , 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 the proximal end 14 of the coil 12 . a plurality of pull / push wires 58 , 60 ( shown and described below with reference to fig2 - 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 . fig2 - 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 fig4 ) 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 fig4 , 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 has a helical surface . the interior ( proximal ) helical surfaces of the anvils act to bend the clip retainers as described below with reference to fig1 - 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 fig1 ) 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 fig5 - 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 fig1 - 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 fig1 - 24 and as shown by the clip 310 in fig5 . according to this embodiment , as seen best in fig6 - 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 fig5 , 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 pre - bent in the bridge area to facilitate movement through the angled channels . fig2 illustrates an enlarged portion of the clip applier of fig5 showing that the clip 310 rests inside an applier groove 54 ′, 56 ′ and is bent by the anvil 48 ′ as it pierces a folded over portion of body tissue 500 . referring now to fig9 , a third embodiment of the jaws 22 ″, 24 ″ is illustrated . the jaws 22 ″, 24 ″ are not identical to each other and are designed for use with clips of the type illustrated in fig1 - 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 ) as described in co - owned ser . no . 10 / 010 , 908 , whereas the groove 56 ″ continues on to the interior of the anvil 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 fig1 - 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 fig1 - 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 fig1 , 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 fig1 . as the jaws are closed the medial teeth of the jaws puncture the invaginated fundus as shown in fig1 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 fig1 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 fig1 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 fig1 . 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 fig1 - 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 . no . 09 / 931 , 528 and 60 / 292 , 419 . fig1 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 fig1 , 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 . fig1 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 fig1 , 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 is substantially longer in order to assure that all of the layers of the fundus are punctured . turning now to fig1 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 fig2 - 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 fig1 . 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 fig1 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 fig1 . 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 fig1 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 . in one embodiment , each of the retainers 320 , 322 extend from their respective arms 312 , 314 in a direction that is substantially parallel to , or at least non - perpendicular to , the respective arm from which it extends . 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 fig2 - 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 fig2 . from fig2 , 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 fig1 and 18 and preferably are of a length at least p 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 . fig2 - 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 fig2 . this is actually two substantially parallel “ b ” shaped fasteners . thus , it may only be necessary to apply a single retainer as shown in fig2 , for example . 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 .
a medical method includes sliding two substantially straight unconnected arms over a fold of body tissue such that a first arm contacts a first portion of the fold and a second arm contacts a second portion . then , each arm is bent completely through the fold such that both of the arms compress the portions of the fold into contact with each other . another method includes releasably coupling first and second substantially linear arms to a bridge , each of the arms having a substantially straight sliding portion and a bendable piercing portion . the arms are slid over opposing sides of two body tissue layers , the first arm sliding over the first layer and the second over the second layer . while the sliding portions of the arms remain substantially straight , each piercing portion is bent completely through the adjacent layer and halfway through the other layer to compress the two layers together .