Patent Publication Number: US-8540740-B2

Title: Apparatus and methods for forming and securing gastrointestinal tissue folds

Description:
PRIORITY CLAIM 
     This application is a continuation of U.S. patent application Ser. No. 12/198,056 filed Aug. 25, 2008, now pending, which is a continuation of U.S. patent application Ser. No. 10/672,375 filed Sep. 25, 2003, now U.S. Pat. No. 7,416,554, which claims priority from U.S. Provisional Patent Application No. 60/500,627 filed Sep. 5, 2003. U.S. Pat. No. 7,416,554 is also a continuation-in-part of both U.S. patent application Ser. No. 10/612,170 filed Jul. 1, 2003, now abandoned, and U.S. patent application Ser. No. 10/639,162 filed Aug. 11, 2003, now U.S. Pat. No. 7,618,426. Both of application Ser. Nos. 10/612,170 and 10/639,162 claim priority to U.S. provisional Patent Application No. 60/433,065, filed Dec. 11, 2002. Each of the applications listed above is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to methods and apparatus for intraluminally forming and securing gastrointestinal (“GI”) tissue folds. More particularly, the present invention relates to methods and apparatus for reducing the effective cross-sectional area of a gastrointestinal lumen. 
     BACKGROUND 
     Morbid obesity is a serious medical condition pervasive in the United States and other countries. Its complications include hypertension, diabetes, coronary artery disease, stroke, congestive heart failure, multiple orthopedic problems and pulmonary insufficiency with markedly decreased life expectancy. 
     Several surgical techniques have been developed to treat morbid obesity, e.g., bypassing an absorptive surface of the small intestine, or reducing the stomach size. These procedures are difficult to perform in morbidly obese patients because it is often difficult to gain access to the digestive organs. In particular, the layers of fat encountered in morbidly obese patients make difficult direct exposure of the digestive organs with a wound retractor, and standard laparoscopic trocars may be of inadequate length. 
     In addition, previously known open surgical procedures may present numerous life-threatening post-operative complications, and may cause atypical diarrhea, electrolytic imbalance, unpredictable weight loss and reflux of nutritious chyme proximal to the site of the anastamosis. Further, the sutures or staples that are often used in these surgical procedures may require extensive training by the clinician to achieve competent use, and may concentrate significant force over a small surface area of the tissue, thereby potentially causing the suture or staple to tear through the tissue. 
     The gastrointestinal lumen includes four tissue layers, wherein the mucosa layer is the top tissue layer followed by connective tissue, the muscularis layer and the serosa layer. One problem with conventional gastrointestinal reduction systems is that the anchors (or staples) must engage at least the muscularis tissue layer in order to provide a proper foundation. In other words, the mucosa and connective tissue layers typically are not strong enough to sustain the tensile loads imposed by normal movement of the stomach wall during ingestion and processing of food. In particular, these layers tend to stretch elastically rather than firmly hold the anchors (or staples) in position, and accordingly, the more rigid muscularis and/or serosa layer must be engaged. This problem of capturing the muscularis or serosa layers becomes particularly acute where it is desired to place an anchor or other apparatus transesophageally rather than intraoperatively, since care must be taken in piercing the tough stomach wall not to inadvertently puncture adjacent tissue or organs. 
     In view of the aforementioned limitations, it would be desirable to provide methods and apparatus for forming gastrointestinal tissue folds that achieve gastric reduction by reconfiguring the GI lumen of a patient. 
     It would be desirable to provide methods and apparatus for forming gastrointestinal tissue folds using anchors that can be reconfigured from a reduced delivery profile to an expanded deployed profile. 
     It also would be desirable to provide methods and apparatus for forming gastrointestinal tissue folds, wherein an anchor assembly is extended across stomach folds that include the muscularis and serosa tissue layers. 
     It further would be desirable to provide methods and apparatus for forming gastrointestinal tissue folds, wherein the anchor assembly is deployed in a manner that reduces a possibility of injuring neighboring organs. 
     It still further would be desirable to provide methods and apparatus for forming gastrointestinal tissue folds, wherein reduced training of a clinician is required to achieve competent use of the anchor assembly. 
     SUMMARY 
     In view of the foregoing, it is an object of the present invention to provide methods and apparatus for forming gastrointestinal tissue folds that achieve gastric reduction by reconfiguring the  81  lumen of a patient. 
     It is another object of the present invention to provide methods and apparatus for forming gastrointestinal tissue folds using anchors that can be reconfigured from a reduced delivery profile to an expanded deployed profile. 
     It is an additional object of this invention to provide methods and apparatus for forming gastrointestinal tissue folds in which an anchor assembly is extended across stomach folds that include the muscularis and serosa tissue layers. 
     It is a further object of the present invention to provide methods and apparatus for forming gastrointestinal tissue folds, wherein the anchor assembly is deployed in a manner that reduces a possibility of injuring neighboring organs. 
     It is yet another object to provide methods and apparatus for forming gastrointestinal tissue folds, wherein reduced training of a clinician is required to achieve competent use of the anchor assembly. 
     These and other objects of the present invention are accomplished by providing a catheter configured for advancement into a patient&#39;s gastrointestinal lumen to form a gastrointestinal tissue fold. In one preferred embodiment, the catheter has a distal region including a tissue grabbing assembly adapted to engage and stretch a portion of the tissue wall of the GI lumen at a first tissue contact point. A second tissue contact point is then established with the tissue wall at a location initially proximal of, or in line with, the first tissue contact point. The tissue engaged by the tissue grabbing assembly then is moved to a position proximal of the second tissue contact point to form a tissue fold, and an anchor assembly may be delivered across the tissue fold. Preferably, delivery of the anchor assembly across the tissue fold includes delivering the anchor assembly across the muscularis and serosa layers of the tissue wall. 
     In a preferred embodiment, the tissue grabbing assembly is carried on a first flexible tube associated with the distal region of the catheter, and the anchor assembly is delivered by an anchor delivery system disposed within a second flexible tube associated with the distal region of the catheter. The tissue grabbing assembly may comprise any of a number of mechanisms configured to engage the tissue wall, including a pair of jaws configured to move between open and closed positions, a plurality of linearly translating barbs, or one or more needles or hooks. The first tissue contact point may be moved from a tissue engagement position distal to, or in line with, the second tissue contact point, to the tissue folding position by any of a number of mechanisms, including a hinge assembly or a treadmill assembly. 
     More preferably, the distal region of the catheter includes a bendable section that permits the first tissue contact point to be positioned relative to the second tissue contact point so that the tissue fold is oriented substantially perpendicular to the anchor delivery system. In this manner, the anchor delivery system, when deployed, pierces the tissue fold and exits into the interior of the GI lumen, rather than the exterior of the tissue wall, thereby reducing a risk of injury to adjacent organs. 
     The anchor assembly delivery system of the present invention preferably comprises a needle or obturator adapted to pierce the tissue fold and deliver an anchor assembly. In one preferred embodiment, the anchor assembly comprises a pair of rod-like anchors that are delivered through a needle in a reduced delivery profile, wherein the longitudinal axis of the rods is substantially parallel to the longitudinal axis of the needle. Once ejected from the needle, the rods rotate about 90 degrees to engage the tissue. In other embodiments, the anchor assembly may comprise anchors of various shaped delivered, for example, over the exterior of an obturator. 
     Methods of using the apparatus of the present invention also are provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which: 
         FIGS. 1A and 1B  are, respectively, a side view and detail view of apparatus of the present invention for forming a gastrointestinal fold in accordance with the principles of the present invention; 
         FIGS. 2A and 2B  are side-sectional views of a tissue grabbing assembly suitable for use with the apparatus of  FIG. 1 ; 
         FIGS. 3A-3E  are side views illustrating a method of using the apparatus of  FIG. 1  to form a gastrointestinal fold; 
         FIGS. 4A-4C  are side-sectional views of an anchor assembly and delivery system suitable for use with apparatus of the present invention; 
         FIGS. 5A and 5B  are side-sectional views of another anchor assembly suitable for use with apparatus of the present invention; 
         FIGS. 6A and 6B  are side-sectional views of another alternative anchor assembly suitable for use with apparatus of the present invention; 
         FIGS. 7A-7C  are, respectively, a schematic side-sectional view of a unidirectionally adjustable anchor assembly suitable for use with apparatus of the present invention, schematic side-sectional views of alternative techniques for fixing the distal anchor of the assembly, and a cross-sectional view of the proximal anchor taken along section line A-A of  FIG. 7A ; 
         FIGS. 8A and 8B  are schematic cross-sectional views illustrating the unidirectional adjustment capability of the anchor assembly of  FIG. 7   j    
         FIGS. 9A-9C  are schematic cross-sectional views of alternative embodiments of the proximal anchor of the anchor assembly of  FIG. 7   j    
         FIGS. 10A and 10B  are schematic cross-sectional views of an alternative unidirectionally adjustable anchor assembly suitable for use with apparatus of the present invention; 
         FIGS. 11A-11C  are, respectively, a schematic side-view of another alternative unidirectionally adjustable anchor assembly suitable for use with the present invention, and cross-sectional views of the same taken along section line B-B of FIG.  11 Aj 
         FIG. 12  is a schematic cross-sectional view of an alternative unidirectionally adjustable anchor assembly comprising pivoting paddles; 
         FIG. 13  is a schematic cross-sectional view of an alternative unidirectionally adjustable anchor assembly comprising spring material; 
         FIGS. 14A-14B  are schematic side-sectional views of alternative unidirectionally adjustable anchor assemblies comprising one-way valves; 
         FIGS. 15A-15C  are side-sectional and detail views of alternative unidirectionally adjustable anchor assemblies comprising slipknots; 
         FIGS. 16A-16C  are, respectively, a schematic side-sectional view of a bidirectionally adjustable anchor assembly comprising a locking mechanism, and cross-sectional views of the same taken along section line C-C of FIG.  16 Aj 
         FIGS. 17A-17D  are perspective views of alternative anchors suitable for use with the anchor assemblies of the present invention; 
         FIGS. 18A-18D  are side views of alternative apparatus for forming a gastrointestinal fold; 
         FIG. 19  is a cross-sectional view of the apparatus of  FIGS. 18A-18D ; 
         FIGS. 20A-20D  are side views of further alternative apparatus for forming a gastrointestinal tissue fold in accordance with the principles of the present invention; 
         FIGS. 21A-21G  are schematic side-sectional views of an anchor delivery system adapted for use with the adjustable anchor assemblies of  FIGS. 7-17 , illustrating a method of delivering the unidirectionally adjustable anchor assembly of  FIG. 7  across a tissue fold; 
         FIGS. 22A and 22B  are, respectively, a schematic side-view, partially in section, and an end-view of an alternative anchor delivery system adapted for use with the adjustable anchor assemblies of  FIGS. 7-17 , wherein the proximal anchor is disposed within a separate delivery tube; 
         FIG. 23  is a schematic side-sectional view or an alternative anchor delivery system adapted for use with the adjustable anchor assemblies of  FIGS. 7-17 , wherein both the proximal and distal anchors are loaded within the needle; and 
         FIG. 24  is a schematic side-sectional view of an alternative embodiment of the anchor delivery system of  FIG. 23  comprising motion limitation apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     In accordance with the principles of the present invention, methods and apparatus are provided for intraluminally forming and securing gastrointestinal (“GI”) tissue folds, for example, to reduce the effective cross-sectional area of a GI lumen. These methods and apparatus may be used to treat obesity by approximating the walls of a gastrointestinal lumen to narrow the lumen, thus reducing the area for absorption in the stomach or intestines. More particularly, the present 10 invention involves endoscopic apparatus that engages a tissue wall of the gastrointestinal lumen, creates a tissue fold and disposes an anchor assembly through the tissue fold. Preferably, the anchor assembly is disposed through the muscularis and/or serosa layers of the gastrointestinal lumen. In operation, a distal tip of the probe engages the tissue and then moves the engaged tissue to a proximal position relative to the catheter tip, thereby providing a substantially uniform placation of predetermined size. 
     Formation of a tissue fold preferably is accomplished using two tissue contact points that are separated by a linear or curvilinear distance, wherein the separation distance between the tissue contact points affects the length and/or depth of the fold. In operation, a tissue grabbing assembly engages the tissue wall in its normal state (i.e., non-folded and substantially flat), thus providing a first tissue contact point. The first tissue contact point then is moved to a position proximal of a second tissue contact point to form the tissue fold. An anchor assembly then may be extended across the tissue fold at the second tissue contact point. 
     More preferably, the first tissue contact point is used to engage and then stretch or rotate the tissue wall over the second tissue contact point to form the tissue fold. The tissue fold is then articulated to a position so that a portion of the tissue fold overlies the second tissue contact point at an orientation that is substantially normal to the tissue fold. An anchor then is delivered across the tissue fold at or near the second tissue contact point. 
     Referring to  FIG. 1 , apparatus  10  of the present invention comprises torqueable catheter  11  having distal region  12  from which first and second interconnected flexible tubes  13  and  14  extend, and proximal region  15  having handle  16  and actuator  17 . Catheter  11  is configured for insertion through a patient&#39;s mouth and esophagus into the gastrointestinal lumen. Tissue grabbing assembly  18  is disposed on the distal end of flexible tube  13 , and is coupled to actuator  17  via control wire  19  that extends through flexible tube  13 . 
     As better illustrated in  FIG. 1B , flexible tubes  13  and  14  are connected via hinge assembly  20  that comprises link  21  attached to flexible tube  13  at pivot point  22  and attached to flexible tube  14  at pivot point  23 . Hinge assembly  20  prevents tissue grabbing assembly  18  from moving more than a predetermined distance relative to distal end  24  of flexible tube  14 . 
     Still referring to  FIG. 1B , flexible tubes  13  and  14  preferably include bendable sections  25  and  26 , respectively, that comprise a plurality of through-wall slots  27  to enhance flexibility of the tube. Preferably, flexible tubes  13  and  14  are made from stainless steel with an etched or laser-cut slot pattern. More preferably, the slot pattern is a sinusoidal repeating pattern of slots perpendicular to the longitudinal axis of tubes  13  and  14 . 
     Referring to  FIGS. 2A and 2B , tissue grabbing assembly  18  comprises pair of jaws  28   a ,  28   b  arranged to rotate about pivot point  29  between an open configuration ( FIG. 2A ) and a closed configuration ( FIG. 2B ). Control wire  19  is coupled via pivot point  30  to arms  31   a  and  31   b . Arms  31   a  and  31   b  are in turn pivotally coupled to jaws  28   a  and  28   b , respectively, at pivot points  32   a  and  32   b . Each of jaws  28   a  and  28   b  preferably includes sharpened teeth  33  disposed near its distal ends to facilitate grasping of the tissue wall of the GI lumen. 
     Control wire  19  is coupled to actuator  17  of handle  16  so that translation of the wire within flexible tube  13  causes the jaws to open or close. In particular, urging control wire distally (as indicated by arrow A in ( FIG. 2A ) moves pivot point  30  distally, thereby forcing the jaws to open. Urging control wire  19  proximally (as indicated by arrow B in  FIG. 2B ) moves pivot point  30  proximally, thereby forcing the jaws to close together. In alternative embodiments, tissue grabbing assembly  18  may comprise a grappling hook or fork, or plurality of needles coupled to the distal end of flexible tube  13 . 
     Flexible tube  14  is affixed to and immovable within catheter  11 , while flexible tube  13  is coupled to catheter  11  only via hinge  20 . Accordingly, when control wire  19  is extended in the distal direction, flexible tube  13  is carried in the distal direction. When control wire  19  is retracted in the proximal direction, flexible tube remains stationary until jaws  28   a  and  28   b  close together, after which further retraction of control wire  19  by moving actuator  17  causes flexible tube  13  to buckle in bendable region  25 , as described hereinafter. 
     Referring now to FIGS.  1  and  3 A- 3 E, operation of apparatus  10  is described to create a tissue fold in a tissue wall of a GI lumen. In  FIG. 3A , distal region  12  of catheter  11  is positioned within a patient&#39;s GI lumen transesophageally, and jaws  28   a  and  28   b  of tissue grabbing assembly  18  are opened by moving actuator  17  to the distal-most position on handle  16 . As depicted in  FIG. 3B , actuator  17  may then be moved proximally until the jaws of tissue grabbing assembly  18  engage a portion of tissue wall W at contact point P 1 . 
     Referring to  FIG. 3C , after the tissue wall has been engaged at contact point P 1 , flexible tube  13  is urged proximally within catheter  11  by further proximal retraction of control wire  19  to stretch tissue wall W and create tissue fold F. During this movement of flexible tube  13 , link  21  of hinge assembly  20  causes tissue grabbing assembly  18  to move from a position distal to distal end  24  of flexible tube  14 , to a position proximal of distal end  24  of flexible tube  14 . Bendable sections  25  and  26  of flexible tubes  13  and  14 , respectively, accommodate any lateral motion caused by operation of hinge assembly  20 . Advantageously, formation of fold F facilitates the penetration of the tissue wall by a needle and subsequent delivery of an anchor assembly, as described hereinafter. 
     Referring to  FIG. 3D , additional proximal movement of actuator  17  causes flexible tubes  13  and  14  to buckle at bendable sections  25  and  26 . Hinge assembly  20  transmits force applied to flexible tube  13  via control wire  19  and actuator  17  to the distal tip  24 . Preferably, flexible tube  14  is configured so that distal tip  24  contacts, and is substantially perpendicular, to tissue fold F at contact point P 2 . As illustrated in  FIG. 3E , once tissue fold F is stretched across distal tip  24  of flexible tube  14 , sharpened needle or obturator  34  may be extended from distal tip  24  of flexible tube  14  to pierce all four layers of the tissue wall W. Sharpened needle or obturator  34  is inserted via inlet  35  to flexible tube  14  on handle  16  (see  FIG. 1A ). 
     As discussed above, the GI lumen comprises an inner mucosal layer, connective tissue, the muscularis layer and the serosa layer. To obtain a durable purchase, e.g., in performing a stomach reduction procedure, the staples or anchors used to achieve reduction of the GI lumen must engage at least the muscularis tissue layer, and more preferably, the serosa layer as well. Advantageously, stretching of tissue fold F across distal tip  24  permits an anchor to be ejected through both the muscularis and serosa layers, thus enabling durable gastrointestinal tissue approximation. 
     As depicted in  FIG. 3E , after tissue fold F is stretched across distal tip  24  of flexible tube  14  to form contact point P 2  with tissue wall W, needle  34  may be extended from distal tip  24  and through tissue fold F. Because needle  34  penetrates the tissue wall twice, it exits within the gastrointestinal lumen, thus reducing the potential for injury to surrounding organs. Once the needle has penetrated tissue fold F, an anchor assembly is ejected through distal tip  24  as described hereinbelow. 
     With respect to  FIGS. 4A-4C , a first embodiment of an anchor assembly suitable for use with the apparatus of the present invention is described. Anchor assembly  36  comprises T-anchor assembly having distal rod  38   a  and proximal rod  38   b  connected by suture  39 . The precise shape, size and materials of the anchors may vary for individual applications. In addition, the suture material also may vary for individual applications. By way of example, the suture material may consist of monofilament wire, multifilament wire or any other conventional suture material. Alternatively, suture  39  may comprise elastic material, e.g. a rubber band, to facilitate adjustment of the distance between the proximal and distal rods. Suture  39  extends through a pair of through-holes  40  in each rod, thereby forming a loop. Alternatively, suture  39  may be attached to the rods via an eyelet or using a suitable adhesive. Preferably, through-holes  40  are located near the center of the rods  38   a  and  38   b.    
     Referring to  FIG. 4B , rods  38   a  and  38   b  may be delivered through needle  34  (see  FIG. 3E ) using push rod  42 . Push rod  42  is adapted to freely translate through flexible tube  14  and needle  34 . Push rod  42  is preferably flexible, so that it may slide through bendable section  26  of flexible tube  14 . In addition, push rod  42  may include notch  43  near its distal end to facilitate grasping and tensioning suture  39  after anchor delivery. 
     During anchor delivery, the longitudinal axis of distal rod  38   a  is substantially parallel to the longitudinal axis of needle  34 . However, once distal rod  38   a  is ejected from needle  34 , suture tension induces the rod to rotate approximately 90 degrees about its longitudinal axis, so that its longitudinal axis is substantially perpendicular to the longitudinal axis of needle  35 . This rotation of distal rod  38   a  prevents it from being pulled back through tissue wall W. 
     Referring to  FIG. 4C , once rod  38   a  is ejected on the distal side of fold F, needle  35  is retracted and push rod  42  is used to eject rod  38   b  on the proximal side of tissue fold F. Like distal rod  38   a , tension in the suture causes proximal rod  38   b  to rotate about 90 degrees once it is ejected from the needle. Notch  43  in push rod  42  then may be employed to tighten suture  39  by any of a variety of mechanisms. Alternatively, suture  39  may comprise an elastic material that dynamically tightens the rods against tissue fold F. 
     Referring now to  FIG. 5A , according to other embodiments, the anchor assembly comprises a T-anchor assembly suitable to be disposed over obturator  50 . More particularly, distal rod  38   a  includes through-hole  51  dimensioned for the passage of obturator tip  52 , and obturator  50  is translatably inserted through flexible tube  14  via inlet  35  of handle  16  (see  FIG. 1A ). Proximal rod  38   b  may be a solid rod that does not include a through-hole for passage of obturator  50 . Alternatively, proximal rod  38   b  may include a throughhole for the passage of the obturator. Preferably, obturator tip  52  is sharpened to facilitate tissue penetration. 
     With respect to  FIG. 5B , once rod  38   a  is ejected on the distal side of fold F, it rotates into a position substantially parallel to tissue wall W and perpendicular to the longitudinal axis of the obturator. Obturator  50  then is retracted and proximal rod  38   b  is ejected from flexible tube  14 . More particularly, when flexible tube  14  is retracted from tissue wall W, proximal rod  38   b  is pulled through distal tip  24 . Proximal rod  38   b  then rotates substantially 90 degrees as it is ejected from flexible tube  14  so that rod  38   b  is urged against tissue wall W. 
     Referring to  FIG. 6A , according to further embodiments, anchor assembly  55  comprises a T-anchor assembly similar to the embodiment depicted in  FIG. 4A . However, anchor assembly  55  includes fine wire tether  56  that may be twisted to maintain the tension between rods  38   a  and  38   b.    
     With respect to  FIG. 6B , a method of delivering anchor assembly  55  is described. Initially, distal rod  38   a  is delivered across both tissue walls using needle  34 . The needle then is retracted to release distal rod  38   a  so that it engages the tissue wall. Next, needle  34  is retracted to release proximal rod  38   b , so that it too rotates into engagement with the tissue wall. A proximal portion of the wire tether is captured by notch  43  of push rod  42  (see  FIG. 4B ), and the push rod is rotated to cause proximal rod  38   b  to clamp down on the tissue fold. Because wire tether  56  is twisted by rotation of push rod  42 , it maintains the desired force on the tissue walls. 
     Referring now to  FIG. 7 , a unidirectionally adjustable anchor assembly suitable for use with apparatus of the present invention is described. Anchor assembly  60  comprises distal anchor  62  and unidirectionally adjustable proximal anchor  64 , which are connected by suture  39 . Distal anchor  62  is translationally fixed with respect to suture  39 . Such fixation may be achieved in a variety of ways. For example, as seen in  FIG. 7A , distal anchor  62  may comprise a pair of through-holes  63 , located near the center of anchor  62  and through which suture  39  is threaded and tied off at knot  65 . 
       FIG. 7B  provides alternative techniques for fixing the distal anchor. As seen in FIG.  7 B(i), distal anchor  62  may comprise hollow tube T having opening  0 . A distal end of suture  39  is passed through opening  0  and formed into knot K, which is dimensioned such that it cannot pass through opening  0 , thereby fixing the distal anchor with respect to the suture. In order to facilitate formation of knot K, distal anchor  62  optionally may comprise distal opening DO, which is dimensioned such that knot K may pass therethrough. The distal end of suture  39  may be passed through distal  17  opening DO, knotted, and then pulled back within hollow tube T of anchor  62  until it catches at opening o. 
     A drawback of the fixation technique described with respect to FIG.  7 B(i) is a risk of suture  39  being torn or cut due to rubbing against opening o. In  FIG. 7B  (ii), hollow tube T comprises first end E to which is connected wire loop L, which may be formed, for example from a nickel-titanium alloy (“Nitinol”). Suture  39  passes through the wire loop before terminating at knot K. Knot K is dimensioned such that it cannot pass back through the wire loop. Wire loop L directs suture  39  through opening  0 , thereby reducing rubbing of the suture against the opening and reducing a risk of tearing or cutting of suture  39 . 
       FIG. 7B  (iii) provides yet another alternative technique for fixing the distal anchor with respect to the suture. Distal anchor  62  again comprises hollow tube T having opening o. Rod R is disposed within tube T, and the ends of the tube may be either closed or crimped to rod R, such that the rod is maintained within the tube. The distal end of suture  39  is threaded through opening  0 , around rod R, and back out opening o. The suture is then knotted at knot K, thereby fixing distal anchor  62  with respect to suture  39 . 
     In addition to the techniques shown in  FIGS. 7A and 7B , suture  39  alternatively may be fixed with respect to anchor  62  by other means, for example, via a knotted eyelet or via a suitable adhesive. Additional techniques will be apparent to those of skill in the art. While anchor  62  is illustratively shown as a rod- or T-type anchor, any of a variety of anchors, per se known, may be used as distal anchor  62 . Exemplary anchors are described in co-pending U.S. patent application Ser. No. 10/612,170, filed Jul. 1, 2003, which is incorporated herein by reference in its entirety. Additional anchors are described hereinbelow with respect to  FIG. 17 . 
     Referring again to  FIG. 7A , adjustable proximal anchor  64  comprises outer cylinder  66  having first end  67   a  and second end  67   b , as well as first opening  68   a  and second opening  68   b . First and second openings  68  are preferably disposed near the center of cylinder  66  and approximately 180.degree. apart. Anchor  64  further comprises first flexible rod  70   a  and second flexible rod  70   b , both of which are disposed within outer cylinder  66  and coupled to first and second ends  67  of cylinder  66 . Rods  70  may be formed, for example, from Nitinol or from a polymer, and may be separated from one another by small gap G. As with the previous anchor assemblies, the precise shape, size and materials of the anchors and suture may vary as required for specific applications. 
     As best seen in  FIG. 7C , suture  39  passes from distal anchor  62  through first opening  68   a  of proximal anchor  64 , around second flexible rod  70   b , around first flexible rod  70   a , between rods  70   a  and  70   b , and out through second opening  68   b . This suture winding provides a unidirectional adjustment capability that allows a length L of suture  39  disposed between distal anchor  62  and proximal anchor  64  to be shortened. However, the suture winding precludes an increase in length L.  FIG. 8  illustrate the mechanism of this unidirectional adjustment capability in greater detail. Optionally, suture  39  may be tied off proximal of anchor  64  at knot  69 , thereby forming a proximal loop of suture to facilitate deployment and/or adjustment of anchor assembly  60 . 
     In  FIG. 8A , a proximally-directed force F.sub.1 is applied to suture  39  proximal of adjustable anchor  64 , while anchor  64  is held stationary or is advanced  19  distally. A portion of force F.sub.1 is transferred through suture  39  to second flexible rod  70   b , which causes rod  70   b  to bow, thereby increasing gap G and allowing suture  39  to freely pass between rods  70   a  and  70   b  and through proximal anchor  64 , facilitating unidirectional adjustment. When anchor  64  is held stationary while suture  39  is retracted proximally, distal anchor  62  retracts proximally towards anchor  64 . Alternatively, when anchor  64  is advanced distally while suture  39  is retracted proximally, distal anchor  62  either remains stationary or retracts proximally towards proximal anchor  64 , depending upon a degree of distal advancement of proximal anchor  64 . Regardless, length L of suture  39  disposed between anchors  62  and  64  is decreased, thereby unidirectionally adjusting a distance between the anchors. 
     In  FIG. 8B , a distally-directed force F.sub.2 is applied to suture  39  distal of adjustable anchor  64 . Force F.sub.2 may be applied, for example, by tissue compressed between anchors  62  and  64 . Compressed tissue stores energy in a manner similar to a compression spring and seeks to push anchors  62  and  64  apart after unidirectional tightening. Force F.sub.2 causes the loop of suture  39  around first and second rods  70  to tighten, thereby bowing both rods inward and closing gap G such that suture  39  is friction locked between first and second flexible rods  70 . In this manner, the length L of suture between anchors  62  and  64  may be selectively decreased but cannot be increased. 
     As will be apparent to those of skill in the art, the magnitude of force required to unidirectionally adjust length L may be altered in a variety of ways. For example, a length, flexibility or diameter of rods  70  may be altered. Likewise, the elasticity or diameter of suture  39  may be altered. Initial gap G may be increased or decreased. Further still, the materials used to form rods  70  and suture  39  may be changed to alter material  70  or suture  39  may comprised a lubricous coating. Additional methods for varying the magnitude of force, a few of which are described hereinbelow with respect to  FIG. 9 , will be apparent in view of this disclosure and are included in the present invention. 
     Referring now to  FIG. 9 , alternative anchors  64  are described. In  FIG. 9A , flexible rods  70  of proximal adjustable anchor  64 ′ are rotated with respect to openings  68  (or vice versa). When utilizing the suture winding described in  FIGS. 7 and 8 , rotation of rods  70  up to 108.degree. clockwise progressively increased magnitude of the friction lock is increased when force is applied in the manner described with respect to  FIG. 8B . However, friction is also increased when unidirectionally adjusting the length of suture between the proximal and distal anchors by applying force in the manner described with respect to  FIG. 8A . Rotation of rods  70  more than about 108.degree. clockwise would case anchor  64 ′ to friction lock regardless of which direction force were applied suture  39 , thereby negating the unidirectional adjustment capability. Counterclockwise rotation of rods  70  with respect to openings  68  would initially reduce friction during force application to suture  39  in either direction. It is expected that counterclockwise rotation in excess of about 90.degree. would eliminate the friction lock described in  FIG. 8B  and allow bidirectional adjustment. Continued counterclockwise rotation beyond about 450.degree. would reverse the directions of friction lock and unidirectional adjustment, while counterclockwise rotation beyond about 720.degree. would result in friction lock regardless of which direction force were applied to suture  39 . 
     As discussed previously, openings  68  of cylinder  66  of anchor  64  are preferably disposed approximately 180.degree. apart from one another. However, in order to increase the friction lock force without significantly increasing friction during unidirectional adjustment, first opening  68   a  may be rotated counterclockwise with respect to second opening  68   b  (or vice versa), as seen with anchor  64 ″ of  FIG. 9B . In this manner, first opening  68   a  is no longer in line with rods  70 , while second opening  68   b  remains in line with rods  70 . When force F.sub.1 is applied to anchor  64 ″, second flexible rod  70   b  is able to bow outward and increase gap G, thereby facilitating unidirectional adjustment. Likewise, when force F.sub.2 is applied to the anchor, gap G is closed more tightly upon suture  39 , thereby increasing the friction lock force. If first opening  68   a  alternatively were rotated clockwise with respect to the second opening, it is expected that the friction lock force would be decreased. 
     In  FIG. 9C , proximal adjustable anchor  64 ′″ comprises an alternative suture winding. Suture  39  passes from distal anchor  62  through first opening  68   a  of anchor  64 ′″, around second flexible rod  7 Gb, around first flexible rod  70   a , back around second flexible rod  70   b , between rods  70   a  and  70   b , and out through second opening  68   b . As with the suture winding described with respect to anchor  64  of  FIGS. 7 and 8 , the suture winding illustrated in  FIG. 9C  provides a unidirectional adjustment capability that allows a length L of suture  39  disposed between distal anchor  62  and proximal anchor  64 ′″ to be shortened. However, this suture winding  22  precludes an increase in length L. Additional unidirectionally adjustable suture windings will be apparent to those of skill in the art. 
     With reference to  FIG. 10 , an alternative unidirectionally adjustable anchor comprising three rods is described. Anchor assembly  80  comprises distal anchor  62  and proximal anchor  82 . Unidirectionally adjustable proximal anchor  82  comprises outer cylinder  84  having first end  85   a  and second end  85   b  (not shown), as well as first opening  86   a  and second opening  86   b . First and second openings  86  are preferably disposed near the center of cylinder  84  and approximately 180.degree. apart. Anchor  82  further comprises first flexible rod  88   a , second flexible rod  88   b  and third flexible rod  88   c , all of which are disposed within outer cylinder  66  and coupled to first and second ends  85  of cylinder  64 . Rods  88  are separated from one another by gaps G.sub.1 and G.sub.2. 
     Suture  39  passes from distal anchor  62  through first opening  86   a  of proximal anchor  82 , around first rod  88   a , between first rod  88   a  and second rod  88   b , between second rod  88   b  and third rod  88   c , around third rod  88   c , back to and around first rod  88   a , and out through second opening  86   b . As seen in  FIG. 10A , when force F 1  is applied to suture  39 , gaps G.sub.1 and G.sub.2 remain open, thereby facilitating unidirectional adjustment/shortening of length L of suture  39  disposed between distal anchor  62  and proximal anchor  82 . As seen in  FIG. 10B , when force F.sub.2 is applied to suture  39 , gaps G.sub.1 and G.sub.2 close down upon suture  39 , thereby forming a friction lock that precludes an increase in length L of suture  39 . 
     Referring now to  FIG. 11 , an alternative three rod anchor assembly is described. The unidirectionally adjustable anchors described hereinabove with respect to  FIGS. 7-10  all comprise rods disposed within a cylinder  23  having openings for passage of a suture. The openings act to center the suture with respect to the rods and can be used to alter magnitudes of force applied during adjustment and friction locking, as discussed previously. However, such openings present a risk of tearing or cutting the suture as the suture slides through the openings. 
     As seen in  FIG. 11 , anchor assembly  90  comprises distal anchor  62  and proximal anchor  92 . Unidirectionally adjustable proximal anchor  92  comprises first flexible rod  94   a  and second flexible rod  94   b , as well as rigid rod  96 , which is preferably larger in diameter than first and second rods  94 . Flexible rods  94  are preferably fabricated from Nitinol or a polymer, while rigid rod  96  is preferably fabricated from stainless steel or a polymer. Alternative materials will be apparent to those of skill in the art. 
     Anchor  92  further comprises first outer cylinder  98   a  and second outer cylinder  98   b , which are crimped to the ends of first and second rods  94 , and rigid rod  96 . As an alternative to crimping, first and second cylinders  98  may each comprise an end cap (not shown) to which the rods are coupled. First and second cylinders  94  do not span a central portion of anchor  92 . Flexible rods  94  are separated from one another by gap G.sub.1, while rods  94  are separated from rigid rod  96  by gap G.sub.2. 
     Anchor  92  comprises three rods, but, unlike anchor  82  of  FIG. 10 , suture  39  is only wrapped around two of them to achieve unidirectional adjustment. As best seen in  FIGS. 118 and 11C , the illustrative suture winding of anchor assembly  90  is similar to that described previously with respect to anchor assembly  60  of  FIGS. 7 and 8 . The break between first and second cylinders  98  acts to center suture  39  with respect to the  24  rods, as seen in  FIG. 11A , while rigid rod  96  acts to stiffen and reduce rotation of anchor  92  as it directs suture  39  about flexible rods  94 . 
     Suture  39  passes from distal anchor  62  to proximal anchor  92 , between rigid rod  96  and flexible rods  94 , around second flexible rod  94   b , around first flexible rod  94   a , between rigid rod  96  and first flexible rod  94   a , between flexible rods  94   a  and  94   b , and out. As seen in  FIG. 11A , when force F 1  is applied to suture  39 , flexible rods  94  are forced apart and gap G.sub.1 widens while gap G 2  remains substantially constant, thereby allowing unidirectional adjustment of length L of suture  39  disposed between distal anchor  62  and proximal anchor  92 . As seen in  FIG. 11B , when force F.sub.2 is applied to suture  39 , gap G.sub.1 closes down upon suture  39 , thereby forming a friction lock that precludes an increase in length L of suture  39 . Gap G.sub.2 again remains substantially constant. 
     With reference to  FIG. 12 , an alternative unidirectionally adjustable anchor assembly comprising pivots is described. Anchor assembly  100  comprises distal anchor  62  and proximal anchor  102 . Unidirectionally adjustable proximal anchor  102  comprises outer cylinder  103  having first end  104   a  and second end  104   b  (not shown), as well as first opening  105   a  and second opening  105   b . First and second openings  105  are preferably disposed near the center of cylinder  103  and approximately 180.degree. apart. Anchor  102  further comprises first rod or paddle  106   a  and second rod or paddle  106   b , both of which are disposed within outer cylinder  103  and coupled to the first and second ends of cylinder  103  by pins  107 , which pass through pivot holes  108 . In this manner, first and second paddles  106  are able to rotate about pivot holes  108 . Paddles  106  may be formed, for example, from stainless steel or a polymer, and are separated from one another by gap G. As with the previous anchor assemblies, the precise shape, size and materials of the anchors, as well as suture  39 , may vary as required for specific applications. 
     Suture  39  illustratively passes from distal anchor  62  through first opening  10   sa  of proximal anchor  102 , around second paddle  106   b , around first paddle  106   a , between paddles  106   a  and  106   b , and out through second opening  105   b . The placement of pivot holes  108  ensures that application of force F.sub.1, as described hereinabove, causes paddles  106  to rotate apart from one another and expand gap G, thereby enabling unidirectional adjustment. Likewise, application of previously discussed force F.sub.2 causes paddles  106  to rotate together, thereby closing gap G and pinching suture  39  between the paddles in a friction lock. An increase in the magnitude of force F.sub.2 serves to rotate paddles  106  together more tightly, thereby increasing the magnitude of the friction lock acting upon suture  39  between the paddles. In this manner, unidirectional adjustment is achieved. 
     Referring now to  FIG. 13 , an alternative unidirectionally adjustable anchor assembly comprising spring material is described. Anchor assembly  110  comprises distal anchor  62  and proximal anchor  112 . Unidirectionally adjustable proximal anchor  112  comprises outer cylinder  113  having first end  114   a  and second end  114   b  (not shown), as well as first opening  115   a  and second opening  115   b . First and second openings  115  are preferably disposed near the center of cylinder  113  and approximately 180.degree. apart. Anchor  112  further comprises first rod  116   a  and second rod  116   b  that are separated by gap G, as well as spring material  118 , all of which are disposed within outer cylinder  113 . Spring material  118  abuts rods  116 , which preferably are substantially the same length as cylinder  113 , and may either move freely within cylinder  113  or may be coupled to the ends (not shown) of cylinder  113 . Spring material  118  may also move freely within cylinder  113  or may be coupled to the cylinder, and comprises lumen  119  having a diameter that is preferably equal to or less than the diameter of suture  39 . Spring material  118  may comprise, for example, a compressible biocompatible foam, which acts as a compression spring. 
     Suture  39  passes from distal anchor  62  to proximal anchor  112  through first opening  115   a  of cylinder  113 , between rods  116 , through lumen  119  of spring material  118 , and out through second opening  115   b . Lumen  119  snugly contacts suture  39  such that application of force F.sub.1 causes friction between the suture and the spring material to compress the spring material against the wall of cylinder  114 , thereby reducing a stress applied to rods  116  by spring material  118  and increasing gap G such that unidirectional adjustment of length L of suture  39  disposed between distal anchor  62  and proximal anchor  102  may proceed. Application of force F.sub.2 stretches spring material  118  against rods  116 , thereby increasing the stress applied to the rods by the spring material and closing gap G such that suture  39  is friction locked between rods  116 . 
     With reference to  FIG. 14 , alternative unidirectionally adjustable anchor assemblies comprising one-way valves are described. In  FIG. 14A , anchor assembly  120  comprises distal anchor  62  and proximal anchor  122 . Unidirectionally adjustable proximal anchor  122  comprises outer cylinder  124  having first and second ends  125   a  and  125   b , as well as first opening  126   a  and second opening  126   b . First and second openings  126  are preferably disposed near the center of cylinder  124  and approximately 180.degree. apart. Anchor  122  further comprises first inclined plane  128   a  and second inclined plane  128   b , which are forced into apposition by compression springs  129   a  and  129   b , thereby forming one-way valve V at the junction of the two inclined planes. Inclined planes  128  and springs  129  are disposed within outer cylinder  124 ; springs  129  abut ends  125  of cylinder  124 , as well as the ends of the inclined planes. Suture  39 ′ comprises a plurality of knots or beads B adapted to actuate one-way valve V. 
     Suture  39 ′ passes from distal anchor  62  to proximal anchor  122  through first opening  126   a  of cylinder  124 , between inclined planes  128 , through one-way valve V, and out through second opening  126   b . Application of force F.sub.1 to suture  39 ′ causes a bead B to contact inclined planes  128  and gradually coax them apart by compressing springs  129 , thereby opening valve V and allowing the bead to pass through the valve. Once the bead has passed through valve V, springs  129  force inclined planes  128  back into apposition, thereby closing the valve. Continued application of force F.sub.1 allows multiple beads to pass through the valve, which facilitates unidirectional adjustment of suture length L disposed between distal anchor  62  and proximal anchor  122 . Application of force F.sub.2 causes a bead B of suture  39 ′ to impinge upon the proximal sides of inclined planes  128 . However, force transferred to the planes by the bead is perpendicular to the direction required to compress springs  129  and urge planes  128  apart. As such, the bead B impinging upon the proximal sides of planes  128  is not able to open one-way valve V and pass back through the valve in a distal direction, thereby ensuring only unidirectional adjustment, i.e. shortening, of the length L of suture disposed between the proximal and distal anchors. 
     In  FIG. 14B , an alternative unidirectionally adjustable anchor having a one-way valve is described. Anchor assembly  130  comprises distal anchor  62  and proximal anchor  132 . Unidirectionally adjustable proximal anchor  132  comprises lumen  134  having cantilevered inclined plane  136  disposed therein, which forms one-way valve V. ‘Zip-tie’ fastener  138 , having a plurality of inclined planes  139 , connects proximal anchor  132  and distal anchor  62 . The plurality of inclined planes  1398  are disposed about 180.degree. out of phase with inclined plane  136  of anchor  132 . 
     Fastener  138  passes from distal anchor  62  to proximal anchor  132 , through lumen  134  and past inclined plane  136 . Inclined planes  139  of fastener  138  mesh with inclined plan  139  of fastener  138  may proximally pass one-way valve V when force F.sub.1 is applied to the fastener, thereby enabling unidirectional adjustment of length L of fastener  138  disposed between the proximal and distal anchors. Conversely, when F.sub.2 is applied to the fastener, the proximal side of inclined plane  136  of anchor  132  abuts the distal side of an inclined plane  139  of fastener  138 , and the fastener cannot be drawn distally through proximal anchor  132 , nor can the length L of fastener disposed between the anchors be increased significantly. 
     Referring now to  FIG. 15 , alternative unidirectionally adjustable anchor assemblies comprising a slipknot are described. In  FIG. 15A , anchor assembly  140  comprised distal anchor  142  and proximal anchor  144 . Through-holes  143   a  and  143  extend through distal anchor  142 , while through-holes  145   a  and  145   b  extend through proximal anchor  145 . Preferably, through-holes  143  and  145  are located near the center of anchors  142  and  144 , respectively. 
     The distal end of suture  39  passes through through-hole  145   a  of proximal anchor  144  to distal anchor  142 , where it passes through through-hole  143   a  and back through through-hole  143   b . It then extends from distal anchor  142  back to proximal anchor  144 , where it passes through through-hole  145   b  of the proximal anchor. The distal end of suture  39  is tied off at unidirectional slipknot S, which is located proximal of anchor  144 .  FIG. 158  provides a detail view illustrating formation of slipknot s. 
     As will be apparent to those of skill in the art, application of force F 1  causes suture  39  to slide through through-holes  143  and  145 , and decrease the length L of suture  39  disposed between anchors  142  and  144 . Suture  39  may readily pass through slipknot S in a proximal direction, thereby facilitating unidirectional adjustment of length L. However, application of force F.sub.2 tightens slipknot S and prohibits passage of suture  39  through the slipknot in a distal direction, thereby precluding an increase in length L. 
       FIG. 15C  illustrates an alternative embodiment of anchor assembly  140  wherein the slipknot is disposed within the proximal anchor. Anchor assembly  140 ′ comprises distal anchor  142  and proximal anchor  144 ′. Proximal anchor  144 ′ comprises hollow cylinder or tube  146  having distal openings  147   a  and  147   b , and proximal opening  148 . 
     The distal end of suture  39  passes through proximal opening  148  into the interior of tube  146 . It then passes through distal opening  147   a  of proximal anchor  144 ′ to distal anchor  142 , where it passes through through-hole  143   a  and back through through-hole  143   b . Next, suture  39  extends from distal anchor  142  back to proximal anchor  144 ′, where it passes through distal opening  147   b  into the interior of tube  146  of the proximal anchor. The distal end of suture  39  is tied off at unidirectional slipknot S, which is disposed within tube  146  of anchor  144 ′. Anchor assembly  140 ′ may be unidirectionally adjusted in a manner similar to that described hereinabove with respect to anchor assembly  140  of  FIG. 15A . 
       FIGS. 7-15  illustrate anchor assemblies comprising various mechanisms for achieving unidirectional adjustment of the distance between the proximal and distal anchors. These mechanisms have been provided solely for the sake of illustration and should in no way be construed as limiting. Additional mechanisms for achieving unidirectional adjustment will be apparent to those of skill in the art in view of this disclosure and are included in the present invention. Furthermore, a majority of the anchor assemblies of  FIGS. 7-15  have been described with the distal anchor being fixed relative to the suture, and the proximal anchor being adjustable. However, it should be understood that the distal anchor may alternatively be adjustable and the proximal anchor may be fixed, and/or both anchors may be unidirectionally adjustable, as with anchor assembly  140  of  FIG. 15 . 
     With reference now to  FIG. 16 , a bidirectionally adjustable, anchor assembly comprising a locking mechanism is described. Anchor assembly  150  comprises distal anchor  62  and proximal anchor  152 . As seen in  FIG. 16A , bi-directionally adjustable proximal anchor  152  comprises outer cylinder  153  having first end  154   a  and second end  154   b , as well as first opening  155   a  and second opening  155   b . First and second openings  155  are preferably disposed near the center of cylinder  153  and approximately 90.degree. apart. Proximal anchor  152  further comprises tension spring  158  disposed within outer cylinder  153 . 
     As seen in  FIG. 168 , suture  39  passes from distal anchor  62  to proximal anchor  152  through first opening  155   a , around spring  158 , and out through second opening  155   b . Suture  39  moves freely about tension spring  158  in either direction during application of force F.sub.1 or force F.sub.2, thereby facilitating bi-directional adjustment of suture length L disposed between the proximal and distal anchors. However, as seen in  FIG. 16C , simultaneous application of forces F.sub.1 and F.sub.2 with sufficient magnitude causes suture  39  to force threads T of spring  158  apart, such that suture  39  is trapped between threads T and locked in position, thereby precluding further adjustment of suture length L. 
     The magnitude of forces required to actuate the locking mechanism of proximal anchor  152  and lock suture  39  within threads T of spring  158  may be specified/altered in a variety of ways. For example, the angular spacing of openings  155  about outer cylinder  153  may be altered, the spring constant of spring  158  may be specified, and/or spring  158  or suture  39  may comprise a lubricious coating. Additional techniques will be apparent to those of skill in the art. It is expected that simultaneous application of forces F.sub.1 and F.sub.2 will be encountered when anchor assembly  150  has been deployed across a tissue fold and suture length L has been adjusted such that the tissue fold is compressed. A medical practitioner would then apply force F.sub.1, while the compressed tissue fold would apply force F.sub.2. 
     Although the anchor assemblies of  FIGS. 10-16  have illustratively been described without knots or loops of suture or fastener disposed proximal of the proximal anchor (as seen, for example, with knot  69  on suture  39  of anchor assembly  60  in  FIGS. 7 and 8 ) it should be understood that such loops or knots optionally may be provided in order to facilitate deployment and/or adjustment of the anchor assemblies. Additionally, the previously described anchor assemblies illustratively comprise distal rod- or T-type anchors. However, it should be understood that distal T-anchors have only been provided for the sake of illustration. 
     The distal anchors (as well as the proximal anchors) may comprise any of a variety of anchors, per se known. Exemplary anchors are described in co-pending U.S. patent application Ser. No. 10/612,170, filed Jul. 1, 2003, which is incorporated herein by reference in its entirety. Additional anchors are described hereinbelow with respect to  FIG. 17 . 
     Referring to  FIG. 17A , articulating anchor  160  includes semi-cylindrical base  161 , rod  162  and suture  39 . Rod  162  rotates about pivot point  163  (as indicated by arrow  164 ) between an expanded position (shown in  FIG. 7A ) and a reduced profile position, wherein rod  162  pivots within the semi-cylindrical base  161 . Articulating anchor  160  may be delivered through a tissue fold using needle  34  described hereinabove with respect to  FIG. 3E . Preferably, articulating anchor  160  is biased in the expanded position so that it automatically expands once it is ejected from the needle. 
     With respect to  FIGS. 17B and 17C  the anchors of the present invention also may comprise one or more oblong bodies connected by at least one suture. In  FIG. 17B , anchor  165  comprises elliptical ring  166  having sutures  39  attached at substantially opposite sides of the ring. In  FIG. 17C , anchor  168  comprises angle bracket  169  having a pair of through-holes  170  for suture  39 . In  FIG. 17D , anchor  171  comprises oblong bead  172  having a pair of through-holes  173  for suture  39 . All three anchors  165 ,  168  and  171  (as well as the T-anchors described previously) have a first dimension (e.g., width) that is substantially larger than a second dimension (e.g., height). This dimensional difference necessitates that anchors  165 ,  168  and  171  be inserted within needle (e.g., needle  34  of  FIG. 3E ) in a particular orientation. Once the anchor is ejected through a tissue wall, tension on suture  39  forces the anchor to rotate so that it cannot be pulled back through the tissue wall. As will be understood by those of skill in the art, numerous other anchors may be employed without departing from the scope of the present invention. 
     Referring now to  FIG. 18A , an alternative embodiment of apparatus for forming a tissue fold, constructed in accordance with the principles of the present invention, is described. Apparatus  175  comprises treadmill assembly  176  disposed at distal tip  174  of flexible tube.  177 . Flexible tube  177  is configured to be inserted through a patient&#39;s mouth, esophagus and into the stomach. Treadmill assembly  176  comprises conveyor  180  that circles around a pair of hubs  181   a  and  181   b . Hubs  181   a  and  181   b  rotate about axles  182   a  and  182   b , respectively, and are interconnected by bracket  183 . A plurality of barbs or needles  185  is disposed at substantially regular intervals around the circumference of conveyor  180 . 
     Flexible tube  177  preferably includes a plurality of through-wall slots  186  to enhance flexibility of the tube, yet maintain torqueability. Preferably, flexible tube  177  is made from stainless steel with an etched or laser-cut slot pattern. Preferably, the slot pattern is a sinusoidal repeating pattern of slots perpendicular to the longitudinal axis of the tube. 
     Referring to  FIGS. 18 and 19 , transmission of motive force to treadmill assembly  176  is described. In particular, drive shaft  202  disposed within flexible tube  177  is coupled to a manual knob or motor located at the proximal end of the catheter. The distal tip of drive shaft  202  is provided with beveled gear  203  that meshes with beveled gear  204  provided on axle  182   b . Accordingly, rotation of beveled gear  203  is transmitted to beveled gear  204 , thereby causing axle  182   b  to rotate. Axle  182   b  in turn rotates hub  181   b , actuating conveyor  180 . Reversing the rotation of drive shaft  202  reverses the direction of conveyor  180 . 
     Referring again to  FIGS. 18A-18D , a method of forming a gastrointestinal tissue fold F using apparatus  175  is described. In  FIG. 18A , flexible tube  177  is positioned transesophageally so that treadmill assembly  176  contacts tissue wall W. Preferably, contact should be made at an angle relative to the tissue wall W. For example, an angle of approximately 45 degrees is depicted in  FIG. 8A , while many other angles may be used without departing from the scope of the present invention. 
     When treadmill assembly  176  contacts tissue wall W, needle  185  engages the tissue at contact point P 1  as the needle moves around distal hub  181   a . As depicted in  FIG. 18B , as the needle moves away from distal hub  181   a , tissue wall W is pulled towards proximal end  181   b , thereby forming a small tissue fold F. As the treadmill assembly continues to turn, subsequent needles  185  engage the tissue wall so that it becomes securely engaged to treadmill assembly  176  along the length of conveyor  180 . 
     As depicted in  FIG. 18C , once tissue wall W is securely engaged to treadmill assembly  176 , distal end  174  of flexible tube  177  may be articulated in bendable section  190 , thereby moving treadmill assembly  176  away from tissue wall W. The articulation of flexible tube  177  may be accomplished using a control wire and actuator disposed at the proximal end of the catheter, as previously described with respect to the embodiment of  FIG. 1 . By moving the treadmill assembly away from tissue wall W, additional tissue is pulled proximally and tissue fold F becomes elongated. 
     In  FIG. 18D , tissue fold F is stretched across bendable section  190  of flexible tube  177  to create contact point P 2 . This permits a sharpened needle or obturator to be extended through one of slots  186  of bendable section  190  and across all four layers of the tissue wall W. Advantageously, stretching of tissue fold F across bendable section  190  permits an anchor to be ejected through both the muscularis and serosa layers, thus providing a durable foundation for gastrointestinal tissue approximation. For example, needle  192  may be extended through slot  186  in bendable section  190 , and through the base of tissue fold F, and an anchor assembly (such as described with respect to any of  FIGS. 4-17 ) may be ejected from needle  192  to secure the fold. Alternatively, an obturator (such as described with respect to  FIGS. 5A and 5B ) may be used to pierce the tissue fold at contact point P 2  and deliver the anchor assembly. Treadmill assembly  176  may be disengaged from tissue wall W by reversing the rotation of proximal hub  181   b.    
     Referring now to  FIG. 20A , a further alternative embodiment of apparatus for forming a tissue fold in accordance with the principles of the present invention is described. Apparatus  200  comprises tissue grabbing assembly  18 ′ coupled to the distal end of a flexible tube  177 ′, such as described with respect to the embodiment of  FIG. 18 . Flexible tube  177 ′ preferably includes a plurality of through-wall slots  186 ′ to enhance flexibility of the tube, yet maintain torqueability. In addition, flexible tube  177 ′ may be made from stainless steel with an etched or laser-cut slot pattern, such as a sinusoidal repeating pattern of slots perpendicular to the longitudinal axis of the tube. 
     Tissue grabbing assembly  18 ′ is similar to that described with respect to the embodiment of  FIG. 1 , and comprises a pair of jaws  28   a ′,  28   b ′ arranged to rotate about pivot point  29 ′ between an open configuration and a closed configuration. Each of jaws  28   a ′,  28   b ′ preferably includes sharpened teeth  33 ′ disposed near its distal end to facilitate grasping tissue wall W. 
     With respect to  FIG. 20A , tissue grabbing assembly  18 ′ is positioned transesophageally adjacent to tissue wall W and jaws  28   a ′,  28   b ′ are moved to the open position. Tissue grabbing assembly  18 ′ then is moved into contact with tissue wall W. As depicted in  FIG. 20B , tissue grabbing assembly  18 ′ is used to grab the tissue wall at a first contact point P 1 . After capturing a portion of tissue wall W within jaws  28   a ′,  28   b ′, flexible tube  177 ′ is urged proximally to stretch tissue wall W and create tissue fold F. 
     Referring to  FIG. 20C , once tissue fold F is formed, the distal end of flexible tube  177 ′ is articulated about bendable section  190 ′ to move tissue grabbing assembly  18 ′ away from tissue wall W. Articulation of flexible tube  177 ′ may be controlled using an actuator disposed at the proximal end of the catheter, thus causing tissue fold F to become elongated. 
     In  FIG. 20D , tissue fold F is shown stretched across bendable section  190 ′ so that a sharpened needle or obturator may be extended from one of slots  186 ′ in bendable section  190 ′ and across all four layers of the tissue wall W. Needle  192 ′ then may be extended from slot  186 ′ in bendable section  190 ′ through contact point P 2  and tissue fold F. An anchor assembly (e.g., as described with respect to any of  FIGS. 4-17 ) then may be ejected from needle  192 ′ to secure the fold. Alternatively, an obturator (e.g., as described with respect to  FIGS. 5A and 5B ) may be used to pierce the tissue fold at contact point P 2  and deliver the anchor assembly. 
     With reference now to  FIG. 21 , an anchor delivery system adapted for use with the adjustable anchor assemblies of  FIGS. 7-17  is described. In  FIG. 21 , the anchor delivery system is illustratively shown in use with anchor assembly  60  of  FIG. 7 , but this should in no way be construed as limiting. Also, the delivery system of  FIG. 21  may be used in conjunction with apparatus for forming a tissue fold, such as apparatus  10 ,  175  and  200  described previously, in order to anchor the tissue fold; or may be used for any other application, or in conjunction with any other apparatus, requiring delivery of an anchor assembly. 
     In  FIG. 21A , a distal region of anchor delivery system  250  is disposed adjacent tissue fold F in tissue wall W. Anchor delivery system  250  comprises flexible delivery tube  252  having lumen  253 . Flexible delivery tube  252  may be configured for insertion through a patient&#39;s mouth and esophagus into a gastrointestinal lumen, such as the stomach. Lumen  253  of delivery tube  252  preferably has a diameter of less than about 3 cm, and even more preferably has a diameter of about 2.5 cm. Flexible delivery tube  252  preferably includes a plurality of through-wall slots  254  to enhance flexibility of the tube, yet maintain torqueability. Slots  254  may form bendable section  255 . Preferably, flexible delivery tube  252  is made from stainless steel with an etched or laser-cut slot pattern. The slot pattern is preferably a sinusoidal repeating pattern of slots perpendicular to the longitudinal axis of the tube. 
     Anchor delivery system  250  further comprises delivery needle  260 . Needle  260  preferably has a length of less than 2 cm, and even more preferably has a length of about 1.5 cm. Needle  260  preferably comprises sharpened distal tip  262 , lumen  264 , slot  266  extending proximally from distal tip  262 , and proximal eyelet  268 . 
     Lumen  264  of needle  260  is dimensioned such that a distal anchor may be disposed therein. As discussed previously, anchor delivery system  250  is illustratively described in conjunction with anchor assembly  60  of  FIG. 7 . In  FIG. 21A , distal anchor  62  is disposed within lumen  264  of needle  260 . Suture  39  passes through slot  266  of the needle as the suture extends from distal anchor  62  to proximal anchor  64 . Needle  260  preferably is disposed within lumen  253  of flexible delivery tube  252  distal of bendable section  255 , while proximal anchor  64  preferably is disposed within delivery tube  252  proximal of bendable section  255 . 
     In this arrangement, distal anchor  62  may be deployed through needle  260  while the bendable section is actuated or bent, e.g., when anchor delivery system  250  is used in conjunction with previously described plication apparatus. Proximal anchor  64  subsequently may be advanced through bendable section  255  after the bendable section has once again been straightened. The distance, or length, of suture  39  extending between distal anchor  62 , which is disposed distal of the bendable section, and proximal anchor  64 , which is disposed proximal of the bendable section, is preferably greater than or equal to about 2 cm, and is even more preferably greater than or equal to about 4 cm. 
     Needle  260  is proximally coupled to needle pushrod  270 , which facilitates translation of the needle beyond a distal end of flexible delivery tube  252 . Needle pushrod  270  extends to a control actuator disposed at a proximal end of anchor delivery system  250  (not shown). Pushrod  270  optionally may be spring-loaded (not shown), for example, to facilitate puncture of tissue wall W and passage of needle  260  through tissue fold F. 
     Anchor delivery system  250  further comprises anchor pushrod  280 , which is removably disposed through eyelet  268  of needle  260 , and is configured to eject distal anchor  62  from lumen  264  of needle  260 . As with needle pushrod  270 , anchor pushrod  280  extends to a control actuator disposed at a proximal end of anchor delivery system  250  (not shown). The actuators controlling pushrods  270  and  280  are preferably at least partially coupled so that relative motion between the two pushrods can be limited and/or eliminated, as needed. Pushrod  280  passes through the proximal loop of suture formed by knot  69  on suture  39 , such that the suture loop is threaded between needle pushrod  270  and anchor pushrod  280 . This facilitates unidirectional adjustment of the length of suture disposed between distal anchor  62  and proximal anchor  64 , as described hereinbelow. 
     In  FIG. 21B , pushrods  270  and  280  are simultaneously distally advanced with sufficient force, e.g., via spring-loading, such that sharpened distal tip  262  of needle  260  pierces tissue wall W and is advanced across fold F. Bendable section  255  of flexible delivery tube  252  optionally may be bent during advancement of the needle, as described previously with respect to the plication apparatus (see  FIG. 3E ). Anchor pushrod  280  is then advanced distally with respect to needle pushrod  270  and needle  260 , such that it abuts distal anchor  62  and ejects the anchor from lumen  264  of needle  260  on the distal side of tissue fold F, as seen in  FIG. 21C . Suture  39  likewise is ejected from slot  266  and disposed across fold F. 
     During delivery, the longitudinal axis of distal anchor  62  is substantially parallel to the longitudinal axis of needle  260 . However, once anchor  62  has been ejected from needle  260 , suture tension induces the anchor to rotate approximately 90.degree. about its longitudinal axis, so that its longitudinal axis is substantially perpendicular to the longitudinal axis of needle  260 . This rotation of distal anchor  62  prevents it from being pulled back through tissue wall W. One or both ends of anchor  62  may be flared outward (not shown) to facilitate such rotation upon contact with the tissue wall. 
     In  FIG. 21D , anchor pushrod  280  is retracted proximally within lumen  264  of needle  260 , the needle is retracted within flexibly delivery tube  252  via pushrod  270 , and then delivery system  250  is retracted proximally across tissue fold F. Distal anchor  62  is disposed on the distal side of the tissue fold, suture  39  extends through the fold, and proximal anchor  64  is disposed on the proximal side of the fold within delivery tube  252 . If bendable section  255  were flexed during deployment of distal anchor  62  (see  FIG. 3E ), it is straightened to facilitate delivery of the proximal anchor. 
     Delivery tube  252  is then retracted proximally with respect to pushrods  270  and  280 , causing needle  260  to exit lumen  253  of the delivery tube on the proximal side of tissue fold F, thereby providing space for proximal anchor  64  to exit the lumen. Next, delivery tube  252  or the full delivery system  250  is retracted, such that proximal anchor  64  is ejected from delivery tube lumen  253 , as seen in  FIG. 21E . Delivery tube  252  is then re-advanced and/or pushrods  270  and  280  are simultaneously retracted, such that needle  260  is repositioned within lumen  253  of the delivery tube. 
     Flexible delivery tube  252  is advanced with respect to needle  260 , such that it pushes proximal anchor  64  distally. The proximal suture loop formed by knot  69  on suture  39  catches against the proximal end of needle  260  and anchor pushrod  280 , which pulls distal anchor  62  taut against tissue fold F, as seen in FIG.  21 F. Continued advancement of delivery tube  252  unidirectionally adjusts, i.e. shortens length L of suture  39  disposed between distal anchor  62  and proximal anchor  64 , while forcing proximal anchor  64  against the tissue fold and firmly anchoring the fold between the proximal and distal anchors. 
     Once length L has been adjusted such that anchor assembly  60  firmly anchors tissue fold F in position, anchor pushrod  280  may be retracted proximally with respect to needle pushrod  270  and needle  260 , such that the distal end of anchor pushrod  280  is proximally retracted through eyelet  268  and out of needle  260 . As seen in  FIG. 21G , the suture loop formed by knot  69  on suture  39  slips off the distal end of anchor pushrod  280 , removing anchor assembly  60  from anchor delivery system  250  and allowing the anchor delivery system to be removed from the patient. 
     Delivery system  250  optionally may comprise cutting apparatus (not shown) for removing the portion of suture extending proximally of proximal anchor  64  post-adjustment. Alternatively, secondary apparatus may be provided to remove such proximal length of suture. As yet another alternative, the unneeded length of suture may be left within the patient post-procedure. 
     In order to decrease the number of steps required to deliver and adjust anchor assembly  60 , once distal anchor  62  has been deployed, as in  FIG. 21C , the entire anchor delivery system  250  may be retracted proximally, such that needle  260  is retracted across tissue fold F while still disposed outside of delivery tube lumen  253 . This is in contrast to the method described with respect to  FIG. 21D , wherein the needle is disposed within the delivery tube prior to retraction across the tissue fold. Continued proximal retraction of anchor delivery system  250  or delivery tube  252  deploys proximal anchor  64  from delivery tube lumen  253 . Anchor assembly  60  then may be unidirectionally adjusted, as described previously. 
     As will be apparent to those of skill in the art, when anchor delivery system  250  is used in conjunction with previously described apparatus  10 ,  175  or  200 , to place an anchor assembly across fold F formed by said apparatus, flexible delivery tube  252  may either comprise or be advanced through flexible tube  14 ,  177  or  177 ′, of apparatus  10 ,  175  or  200 , respectively. Likewise needle  260  may comprise needle  34 ,  92  or  92 ′, of apparatus  10 ,  175  or  200 , respectively. Needle  260  may alternatively comprise obturator  50  of  FIG. 5 . 
     Referring now to  FIG. 22 , an alternative anchor delivery system is described. As with anchor delivery system  250  of  FIG. 21 , anchor delivery system  300  of  FIG. 22  is adapted for use with the adjustable anchor assemblies of  FIGS. 7-17 . In  FIG. 22 , the anchor delivery system  300  is illustratively shown in use with anchor assembly  60  of  FIG. 7 , but this should in no way be construed as limiting. Also, delivery system  300  may be used in conjunction with apparatus for forming a tissue fold, such as apparatus  10 ,  175  and  200  described previously, in order to anchor the tissue fold; or may be used for any other application, or in conjunction with any other apparatus, requiring delivery of an anchor assembly. 
       FIG. 22A  illustrates a distal region of anchor delivery system  300 . System  300  comprises flexible delivery tube  302  having lumen  303 . Flexible delivery tube  302  may be configured for insertion through a patient&#39;s mouth and esophagus into a gastrointestinal lumen, such as the stomach. Flexible delivery tube  302  preferably includes a plurality of through-wall slots  304  to enhance flexibility of the tube, yet maintain torqueability. Slots  304  may form bendable section  305 . Preferably, flexible delivery tube  302  is made from stainless steel with an etched or laser-cut slot pattern. The slot pattern is preferably a sinusoidal repeating pattern of slots perpendicular to the longitudinal axis of the tube. 
     Flexible delivery tube  302  further comprises end region  306 , which is coupled to anchor tube  307  having lumen or bore  308 . As best seen in  FIG. 22B , lumen  308  of anchor tube  307  communicates with lumen  303  of delivery tube  302  via through-slot  309 . Proximal anchor  64  is disposed within anchor tube  307 , while distal anchor  62  is disposed within needle  260 ′, which sits within delivery tube  302 . 
     Suture  39  passes out of needle  260 ′ from distal anchor  62  through slot  266 ′. It then crosses from flexible delivery tube  302  to anchor tube  307  via through-slot  309 . After passing through proximal anchor  64 , suture  39  is passed back to delivery tube  302  via the through-slot, and is threaded around anchor pushrod  280 ′, such that the loop of suture formed by knot  69  on suture  39  is disposed between needle pushrod  270 ′ and anchor pushrod  280 ′. 
     Needle  260 ′, needle pushrod  270 ′ and anchor pushrod  280 ′ are substantially the same as needle  260  and pushrods  270  and  280 , respectively, which are described 1.about.hereinabove with respect to anchor delivery system  250  of  FIG. 21 . Furthermore, anchor assembly  60  may be delivered from and adjusted by anchor delivery system  300  in a manner similar to that described hereinabove with respect to system  250 . 
     In  FIG. 22A , anchor tube  307  of anchor delivery system  300  is illustratively shown as a relatively short tube having lumen or bore  308  adapted for disposal of proximal anchor  64  therein. However, it should be understood that anchor tube  307 , lumen  308  and/or through-slot  309  alternatively may extend all or part of the way to a proximal end of flexible delivery tube  302  of delivery system  300 . Advantageously, such an arrangement facilitates loading of anchor assembly  60  from a proximal end of the anchor delivery system and may simplify manufacturing of the system. 
     Anchor delivery system  300  illustratively has been described with a single anchor assembly  60  disposed therein. However, it should be understood that a plurality of anchor assemblies may be loaded within delivery system  300 , thereby facilitating delivery of multiple anchor assemblies across different points of a tissue fold, across different (e.g., adjacent) tissue folds, or across other tissue structures. The plurality of distal anchors  62  preferably are loaded within needle  262 ′ of flexible delivery tube  302 , while the plurality of proximal anchors  64  preferably are loaded within lumen  308  of anchor tube  307 . 
     An advantage of anchor delivery system  300 , as compared to system  250  of  FIG. 21 , is that both the proximal and distal anchors are located distal of the bendable section of the delivery tube during delivery. This reduces an initial length of suture that must be disposed between the anchors, thereby reducing a length of unneeded suture extending proximally of the proximal anchor post-delivery and adjustment. It also simplifies delivery by allowing both the proximal and distal anchors to be delivered while the bendable section of the delivery tube is bent. Additionally, placement of the proximal anchor in a separate anchor tube eliminates a need to eject the needle from the flexible delivery tube on the proximal side of a tissue fold in order to deploy the proximal anchor, thereby reducing a risk of accidental tissue puncture with the needle. 
     With reference to  FIG. 23 , another alternative anchor delivery system is described: As with anchor delivery systems  250  and  300  of  FIGS. 21 and 22 , respectively, anchor delivery system  400  of  FIG. 23  is adapted for use with the adjustable anchor assemblies of  FIGS. 7-17 . Anchor delivery system  400  is illustratively shown in use with anchor assembly  60  of  FIG. 7 , but this should in no way be construed as limiting. Also, delivery system  400  may be used in conjunction with apparatus for forming a tissue fold, such as apparatus  10 ,  175  and  200  described previously, in order to anchor the tissue fold; or may be used for any other application, or in conjunction with any other apparatus, requiring delivery of an anchor assembly. 
       FIG. 23  illustrates a distal region of anchor delivery system  400 . System  400  comprises flexible delivery tube  402  having lumen  403 . Flexible delivery tube  402  may be configured for insertion through a patient&#39;s mouth and esophagus into a gastrointestinal lumen, such as the stomach. Flexible delivery tube  4021  preferably includes a plurality of through-wall slots to enhance flexibility of the tube, yet maintain torqueability. The slots may form bendable section  405 . 
     Anchor delivery system  400  further comprises delivery needle  260 ″, which is disposed within lumen  403  of flexible delivery tube  402  distal of bendable section  405  during delivery. As discussed previously, anchor delivery system  400  is illustratively described in conjunction with anchor assembly  60  of  FIG. 7 . Needle  260 ″ preferably has a length sufficient for both distal anchor  62  and proximal anchor  64  of anchor assembly  60  to be disposed therein; for example, needle  260 ″ preferably has a length of less than about 5 cm, and even more preferably has a length of about 3 cm. Except for an increase in length, needle  260 ″ is substantially the same as needle  260  of  FIG. 21 . 
     In  FIG. 23 , both distal anchor  62  and proximal anchor  64  are disposed within lumen  264 ″ of needle  260 ″. Suture  39  passes through and back through slot  266 ″ of the needle as the suture extends from distal anchor  62  to proximal anchor  64 . Alternatively the length of suture between the proximal and distal anchors may be disposed within the needle during delivery. Advantageously, both the proximal and distal anchors of anchor assembly  60  may be deployed through needle  260 ″ while bendable section  405  is actuated or bent, e.g., while anchor delivery system  400  is used in conjunction with previously described plication apparatus. 
     Needle  260 ″ is proximally coupled to flexible needle pushtube  420 , which facilitates translation of the needle beyond a distal end of flexible delivery tube  402 . As will be apparent to those of skill in the art, needle  260 ″ and needle pushtube  420  optionally may be manufactured as a single piece. Needle pushtube  420  comprises lumen  422 , as well as skive  424  that communicates with lumen  422 . Needle pushtube  420  extends to a control actuator (not shown), which may be spring-loaded, disposed at a proximal end of anchor delivery system  400 . 
     Anchor pushrod  280 ″, which is substantially the same as anchor pushrod  280  described previously, is removably disposed within lumen  422  of needle pushtube  420  distal of skive  424 . As with pushtube  420 , anchor pushrod  280 ″ extends to a control actuator (not shown) disposed at a proximal end of the anchor delivery system. Suture  39  proximally extends from proximal anchor  64  through slot  266 ″ of needle  260 ″, through skive  424  and within lumen  422  of needle pushtube  420 , around anchor pushrod  280 ″ and out through skive  424  to knot  69 . The proximal loop of suture formed by knot  69  is trapped around pushrod  280 ″ and within lumen  422  of the needle pushtube, thereby facilitating unidirectional adjustment of the length of suture disposed between distal anchor  62  and proximal anchor  64 . As an alternative to the proximal loop of suture, knot  69  may be formed on the proximal end of suture  39 , such that the knot is trapped between anchor pushtube  280 ″ and needle pushrod  420  (see knot K of  FIG. 24 ). 
     Anchor assembly  60  may be delivered from and adjusted by anchor delivery system  400  in a manner similar to that described hereinabove with respect to system  250  of  FIG. 21 , with a few alterations. Specifically, during deployment of distal anchor  62 , anchor pushrod  280 ″ is advanced against proximal anchor  64 , which in turn advances in-line distal anchor  62 . The pushrod is advanced a sufficient distance with respect to needle  260 ″ to eject the distal anchor from needle lumen  264 ″, but not so far as to also prematurely eject proximal anchor  64 . Motion limitation apparatus may be provided to ensure that the distal anchor is not prematurely ejected. Exemplary motion limitation apparatus is described hereinbelow with respect to  FIG. 24 ; additional apparatus, per se known, will be apparent. 
     In order to eject proximal anchor  64  from lumen  264 ″ of needle  260 ″, either the needle is retracted until length L of suture  39  disposed between the proximal and distal anchors is pulled taut and pulls the proximal anchor out of the needle lumen, or anchor pushrod  280 ″ is advanced a sufficient distance within the lumen of needle  260 ″ to eject the proximal anchor from the lumen (or a combination thereof). Additionally, in order to release anchor assembly  60  from anchor delivery system  400  post-delivery and adjustment, anchor pushrod  280 ″ is retracted proximal of skive  424  such that the loop of suture  39  formed by knot  69  is no longer trapped within lumen  422  of needle pushrod  420 . 
     A significant advantage of anchor delivery system  400 , as compared to system  250  of  FIG. 21 , is that both the proximal and distal anchors are disposed distal of bendable section  405  of flexible delivery tube  402 . A significant advantage of anchor delivery system  400 , as compared to system  300  of  FIG. 22 , is that both the proximal and distal anchors are disposed within needle  260 ″, thereby eliminating a need for an anchor tube and reducing the profile of the system. 
     Referring now to  FIG. 24 , an alternative embodiment of anchor delivery system  400  is described comprising motion limitation apparatus. Anchor delivery system  400 ′ is substantially the same as system  400 , except that needle pushrod  420 ′ comprises two skives: motion limitation skive  430  and unidirectional adjustment skive  432 , both of which communicate with lumen  422 ′ of the needle pushrod. Suture  39  proximally extends from proximal anchor  64 , through motion limitation skive  430  and within lumen  422 ′ between anchor pushrod  280 ″ and needle pushtube  420 ′. Suture  39  exits skive  430  and is tied off at motion limitation knot K, which is trapped at skive  430  by anchor pushrod  280 ″. Suture  39  then continues proximally to unidirectional adjustment skive  432  and the proximal loop of suture formed by knot  69 , which is trapped at skive  432  around pushrod  280 ″. 
     A length of suture extending between proximal anchor  64  and knot K is specified such that distal anchor  62  may exit lumen  264 ′, of needle  260 ″, but proximal anchor  64  cannot while knot K is trapped at skive  430  by anchor pushrod  280 ″. For example, during delivery of anchor assembly  60  across a tissue fold, advancement of pushrod  280 ″ advances proximal anchor  64 , which in turn advances in-line distal anchor  62  until the distal anchor is ejected from needle lumen  264 ″ on the distal side of the tissue fold. Knot K limits a distance anchor pushrod  280 ″ may be advanced and ensures that proximal anchor  64  is not prematurely deployed. 
     Once anchor delivery system  400 ′ is again disposed on the proximal side of the tissue fold, anchor pushrod  280 ″ is retracted proximal of motion limitation  50  skive  430 , thereby allowing knot K to escape from skive  430  and facilitating deployment of proximal anchor  64 . Proximal anchor  64  may be deployed by either retracting needle  260 ″ until the length of suture between the two anchors is pulled taut and pulls the proximal anchor out of the needle, or by re-advancing pushrod  280 ″ to push the proximal-anchor out of the needle. 
     The anchor assembly may then be unidirectionally adjusted via the suture loop trapped at skive  232 , as described previously. After adjustment has been completed, anchor pushrod  280 ″ is retracted proximal of unidirectional adjustment skive  432 , thereby allowing the loop of suture formed by knot  69  of suture  39  to escape from skive  432 . A significant advantage of anchor delivery system  400 ′, as compared to system  400  of  FIG. 23 , is that motion limitation skive  430  reduces a risk of premature deployment of proximal anchor  64 . 
     Although preferred illustrative embodiments of the present invention are described hereinabove, it will be apparent to those skilled in the art that various changes and modifications may be made thereto without departing from the invention. It is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the invention.