Patent Publication Number: US-2006020276-A1

Title: Apparatus and methods for achieving prolonged maintenance of gastrointestinal tissue folds

Description:
BACKGROUND OF THE INVENTION  
     FIELD OF THE INVENTION  
      The present invention relates to methods and apparatus for achieving prolonged maintenance of gastrointestinal (“GI”) tissue folds by forming, securing and promoting healing of the folds. More particularly, the present invention provides methods and apparatus for remodeling the tissue folds to facilitate their prolonged maintenance.  
      Extreme or 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 orthopaedic problems and pulmonary insufficiency with markedly decreased life expectancy.  
      Several surgical techniques have been developed to treat morbid obesity, including bypassing an absorptive surface of the small intestine, bypassing a portion of the stomach, and reducing or partitioning the stomach size, e.g., via Vertical Banded Gastroplasty (“VBG”) or Magenstrasse and Mill. These procedures may be difficult to perform in morbidly obese patients and/or may present numerous potentially life-threatening post-operative complications. Thus, less invasive techniques have been pursued.  
      U.S. Pat. Nos. 4,416,267 and 4,485,805 to Garren et al. and Foster, Jr., respectively, propose insertion of an inflated bag within a patient&#39;s stomach to decrease the effective volume of the stomach that is available to store food. Accordingly, the patient is satiated without having to consume a large amount of food. A common problem with these inflated bags is that, since the bags float freely within the patient&#39;s stomach, the bags may migrate to, and block, a patient&#39;s pyloric opening, the portal leading from the stomach to the duodenum, thereby restricting passage of food to the remainder of the gastro-intestinal tract.  
      Apparatus and methods also are known in which an adjustable elongated gastric band is laparoscopically disposed around the outside of a patient&#39;s stomach near the esophagus to form a collar that, when tightened, squeezes the stomach into an hourglass shape, thereby providing a stoma that limits the amount of food that a patient may consume comfortably. An example of an adjustable gastric band is the LAP-BAND® made by INAMED Health of Santa Barbara, Calif.  
      Numerous disadvantages are associated with using an adjustable gastric band. First, the band may be dislodged if the patient grossly overeats, thereby requiring additional invasive surgery to either reposition or remove the band. Similarly, overeating may cause the band to injure the stomach wall if the stomach over-expands. Laparoscopic disposal of the gastric band around the stomach requires a complex procedure, requires considerable skill on the part of the clinician, and is not free of dangerous complications.  
      In view of the drawbacks associated with prior art techniques for treating morbid obesity, Applicant previously has described methods and apparatus for treating obesity by endoscopically forming and approximating tissue folds within a patient&#39;s stomach in order to reduce an effective cross-section of the stomach. See, for example, co-pending U.S. patent applications Ser. No. 10/735,030, filed Dec. 12, 2003, and Ser. No. TO BE ASSIGNED [Attorney Docket No. 021496-000800US], filed May 7, 2004, both of which are incorporated herein be reference in their entireties. Those references describe formation of serosa-to-serosa gastric plications from the interior of the stomach, such that mucosal tissue is in contact with opposing mucosal tissue along the interior of each gastric tissue fold.  
      Mucosal tissue typically will not fuse or heal together with opposing, contacting mucosal tissue. Thus, gastric tissue folds may require securing elements, such as anchors, clips or suture, to maintain the folds for prolonged periods of time. If such securing elements were ever to be removed or to ever fail, the gastric tissue folds or plications might unfold.  
      U.S. patent Publication Ser. No. 2004/0034371 to Lehman et al., published Feb. 19, 2004 (Ser. No. 10/275,521, PCT filed May 18, 2001), which is incorporated herein by reference in its entirety, describes methods and devices for promoting tissue adhesion. The healing process is utilized to form scar tissue that bonds two tissue surfaces together. A tissue injury is accomplished by destroying the mucosal layer of tissue. After the injury is initiated, the injured tissue surfaces are held in close contact, and, as scar tissue created by the injury forms, the tissue surfaces become bonded together in a permanent union. The Lehman reference does not describe removing at least a portion of the injured tissue prior to tissue bonding, nor does it describe using shape-lockable tools to access and/or manipulate the tissue surfaces.  
      In view of the foregoing, it would be desirable to provide methods and apparatus for achieving prolonged maintenance of gastrointestinal tissue folds without necessitating prolonged use of securing elements.  
      It would be desirable to provide methods and apparatus that promote remodeling of the folds to facilitate their prolonged maintenance.  
     BRIEF SUMMARY OF THE INVENTION  
      Prolonged maintenance of gastrointestinal (“GI”) tissue folds is achieved by providing methods and apparatus for forming, securing and promoting healing of the folds. Such healing may comprise remodeling the tissue folds along region(s) of opposing tissue contact to facilitate prolonged maintenance of the folds. For example, opposing mucosal tissue in contact along each fold may be ablated, abraded, burnt, charred, cut, chemically irritated, biologically irritated or otherwise injured, and preferably removed, to initiate a wound healing response that remodels the tissue and results in scar tissue formation with concomitant fusion of each fold at region(s) of opposing mucosal tissue contact. Such injury and/or removal of mucosal tissue may, for example, be achieved via electromagnetic, thermal, chemical, biologic or mechanical modalities, or a combination thereof. Additional injury/removal modalities will be apparent to those of skill in the art.  
      During the period of time necessary for remodeling/scar tissue formation, securing elements may be utilized to maintain, e.g., temporarily maintain, contact of opposing injured tissue along each tissue fold. Such securing elements optionally may be removed or may biodegrade upon formation of scar tissue. Alternatively, the elements may be left in place indefinitely to reinforce the scar tissue and ensure prolonged maintenance of the tissue folds. However, upon formation of the scar tissue, the securing elements may no longer solely maintain the folds.  
      In one aspect, an injury tool is provided to locally injure mucosal tissue. The injury tool may comprise, for example, an ablation tool, such as a monopolar or bipolar Radio Frequency (“RF”) ablation tool. Alternatively, the injury tool may comprise a mechanical abrasion tool. Additional injury tools will be apparent to those of skill in the art.  
      In one aspect, the injury tool may comprise suction to facilitate tissue engagement and/or aspiration. In another aspect, the tool comprises fluid injection for tissue cooling or cleansing. In yet another aspect, the tool may comprise a removal element for removing injured tissue. Removed tissue may be captured or allowed to pass through the GI tract. The injury tool also may optionally comprise a depth-limiting element that limits a depth of tissue injury.  
      The injury tool preferably is used in combination with additional tools, e.g., for forming and securing the gastrointestinal tissue folds. These tools may comprise tools for accessing, visualizing, grasping, maneuvering, piercing, folding, plicating, approximating, securing, characterizing, sampling and/or suturing GI tissue. One or more of the tools optionally may be steerable or shape-lockable/rigidizable. Additional tools will be apparent to those of skill in the art. Such tools may be provided as a kit or system in combination with the injury tool. Furthermore, the injury tool may be integrated into a multi-functional tool.  
      Methods of using apparatus of the present invention also are provided. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIGS. 1A-1C  are, respectively, a side view, a detail side view and a detail perspective view of one variation of a tissue plication apparatus that may be used to create tissue plications and to deliver securing elements into the tissue.  
       FIGS. 2A-2D  are detail side views, partially in section, illustrating a method of utilizing the apparatus of  FIG. 1  to plicate or fold tissue, and to secure the folded tissue via tissue securing elements.  
       FIGS. 3A-3G  are detail cross-sectional views of apparatus for delivering exemplary tissue anchor securing elements, illustrating a method of maintaining a tissue plication via anchors disposed on proximal and distal sides of the plication.  
       FIG. 4  is a detail cross-sectional view illustrating approximation and securement of multiple, e.g., opposing, tissue folds.  
       FIG. 5  is a detail cross-sectional view illustrating remodeling and fusion of approximated tissue folds.  
       FIG. 6  is a cross-sectional view illustrating an endoluminal gastric reduction procedure achievable through remodeling of approximated tissue folds.  
       FIG. 7  is a schematic perspective view of one variation of an injury tool comprising an ablation tool.  
       FIGS. 8A and 8B  are detail views, partially in section, illustrating variations on a method of using the injury tool of  FIG. 7  in combination with the apparatus of  FIGS. 1-3  to fold, secure, approximate and promote healing or remodeling of tissue folds.  
       FIGS. 9A-9F  are schematic views of multiple variations of the injury tool.  
       FIGS. 10A and 10B  are schematic views of additional variations of the injury tool comprising a mechanical injury element. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Methods and apparatus for achieving prolonged maintenance of gastrointestinal (“GI”) tissue folds by forming, securing and promoting healing of the folds are described below. The methods and apparatus may be utilized within the GI system of a patient in various ways, e.g., transorally, endoluminally, percutaneously, laparoscopically, etc. More particularly, methods and apparatus for remodeling approximated tissue folds to facilitate their prolonged maintenance are disclosed.  
      With reference to  FIGS. 1-4 , in order to form and secure one or more plications or tissue folds within a body lumen of a patient, various methods and devices may be implemented. For example, securing elements, such as suture, anchors and/or clips, as well as assemblies formed therefrom, may be delivered and positioned via an endoscopic apparatus that engages a tissue wall of the gastrointestinal lumen, creates one or more tissue folds, and disposes one or more of the elements through the tissue fold(s). The securing element(s) may be disposed through the muscularis and/or serosa layers of the gastrointestinal lumen. The endoscopic apparatus may also approximate and secure multiple folds together.  
      Generally, in creating a plication through which a securing element may be disposed within or through, a distal tip of a tissue plication apparatus may engage or grasp the tissue and move the engaged tissue to a proximal position relative to the tip of the device, thereby providing a substantially uniform plication of predetermined size.  
      Formation of a tissue fold may, for example, be accomplished using at least two tissue contact areas 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 or grasps the tissue wall in its normal state (i.e., non-folded and substantially flat or non-plicated), thus providing a first tissue contact area. The first tissue contact area then is moved to a position proximal of a second tissue contact area to form the tissue fold. The tissue securing element(s) then may be extended across the tissue fold at the second tissue contact area. Optionally, a third tissue contact point may be established such that, upon formation of the tissue fold, the second and third tissue contact areas are disposed on opposing sides of the tissue fold, thereby providing backside stabilization during extension of the securing element(s) across the tissue fold from the second tissue contact area.  
      The first tissue contact area may be utilized to engage and then stretch or rotate the tissue wall over the second tissue contact area to form the tissue fold. The tissue fold may then be articulated to a position where a portion of the tissue fold overlies the second tissue contact area at an orientation that is substantially normal to the tissue fold. A tissue securing element may then be delivered across the tissue fold at or near the second tissue contact area. An apparatus which is particularly suited to deliver the securing elements described herein may be seen in further detail in co-pending U.S. patent application Ser. No. 10/735,030 filed Dec. 12, 2003 and entitled “Apparatus And Methods For Forming And Securing Gastrointestinal Tissue Folds,” which previously has been incorporated herein by reference.  
      An illustrative side view of a tissue plication assembly  10  which may be utilized with tissue securing elements described herein is shown in  FIG. 1A . The plication assembly  10  generally comprises a catheter or tubular body  12  which may be configured to be sufficiently flexible for advancement into a body lumen, e.g., transorally, endoluminally, percutaneously, laparoscopically, etc. Tubular body  12  may be configured to be torqueable through various methods, e.g., utilizing a braided tubular construction, such that when handle  16  is manipulated and rotated by a practitioner from outside the body, the torquing force is transmitted along body  12  such that the distal end of body  12  is rotated in a corresponding manner.  
      Tissue manipulation assembly  14  is located at the distal end of tubular body  12  and is generally used to contact and form the tissue plication, as mentioned above.  FIG. 1B  shows an illustrative detail side view of tissue manipulation assembly  14  which shows launch tube  18  extending from the distal end of body  12  and in-between the arms of upper extension member or bail  20 . Launch tube  18  may define launch tube opening  24  and may be pivotally connected near or at its distal end via hinge or pivot  22  to the distal end of upper bail  20 . Lower extension member or bail  26  may similarly extend from the distal end of body  12  in a longitudinal direction substantially parallel to upper bail  20 . Upper bail  20  and lower bail  26  need not be completely parallel so long as an open space between upper bail  20  and lower bail  26  is sufficiently large enough to accommodate the drawing of several layers of tissue between the two members.  
      Upper bail  20  is shown in the figure as an open looped member and lower bail  26  is shown as a solid member; however, this is intended to be merely illustrative and either or both members may be configured as looped or solid members. Tissue acquisition member  28  may be an elongate member, e.g., a wire, hypotube, etc., which terminates at a tissue grasper  30 , in this example a helically-shaped member, configured to be reversibly rotatable for advancement into the tissue for the purpose of grasping or acquiring a region of tissue to be formed into a plication. Tissue acquisition member  28  may extend distally from handle  16  through body  12  and distally between upper bail  20  and lower bail  26 . Acquisition member  28  may also be translatable and rotatable within body  12  such that tissue grasper  30  is able to translate longitudinally between upper bail  20  and lower bail  26 . To support the longitudinal and rotational movement of acquisition member  28 , an optional guide or sled  32  may be connected to upper bail  20  or lower bail  26  to freely slide thereon. Guide  32  may also be slidably connected to acquisition member  28  such that guide  32  supports the longitudinal motion of acquisition member  28 .  
      An example of a tissue plication procedure for forming and securing a tissue fold, illustratively with a securing element comprising a tissue anchor, is seen in  FIGS. 2A-2D  and is disclosed in further detail in co-pending U.S. patent application Ser. No. 10/735,030 filed Dec. 12, 2003, which has been incorporated by reference above. As seen in  FIG. 2A , tissue manipulation assembly  14  of plication assembly  10  may be advanced into a body lumen such as the stomach and positioned adjacent to a region of tissue wall  40  to be plicated.  
      Plication assembly  10  illustratively has been advanced through steerable and/or shape-lockable or rigidizable overtube  1  to facilitate positioning of tissue manipulation assembly  14  adjacent the desired region of tissue wall  40 . Furthermore, overtube  1  aids force transmission along plication assembly  10  to facilitate tissue folding, securing, approximating, etc. Exemplary steerable and/or shape-lockable overtubes are described in greater detail in Applicant&#39;s co-pending U.S. patent application Ser. No. TO BE ASSIGNED [Attorney Docket No. 021496-000130US], filed Mar. 9, 2004, and entitled, “Endoluminal Tool Deployment System,” which is incorporated herein by reference in its entirety. During advancement of plication assembly  10  through overtube  1 , launch tube  18  may be configured in a delivery profile such that tube  18  is disposed within or between the arms of upper bail  20  to present a relatively small profile.  
      Once tissue manipulation assembly  14  has been desirably positioned relative to tissue wall  40 , tissue acquisition member  30  may be advanced distally such that tissue acquisition member  30  comes into contact with tissue wall  40  at acquisition location or point  42 . As acquisition member  30  is distally advanced relative to body  12 , guide  32 , if utilized, may slide distally along with member  30  to aid in stabilizing the grasper. If a helically-shaped acquisition member  30  is utilized, as illustrated in  FIG. 2B , it may be rotated from its proximal end at handle  16  and advanced distally until the tissue at point  42  has been firmly engaged by acquisition member  30 . This may require advancement of acquisition member  30  through the mucosal layer and at least into or through the underlying muscularis layer and preferably into or through the serosa layer.  
      The grasped tissue may then be pulled proximally between upper  20  and lower bails  26  via acquisition member  30  such that the acquired tissue is drawn into a tissue fold  44 , as seen in  FIG. 2C . As acquisition member  30  is withdrawn proximally relative to body  12 , guide  32  may also slide proximally to aid in stabilizing the device especially when drawing the tissue fold  44 .  
      Once the tissue fold  44  has been formed, launch tube  18  may be advanced from its proximal end at handle  16  such that a portion  46  of launch tube  18 , which extends distally from body  12 , is forced to rotate at hinge or pivot  22  and reconfigure itself such that portion  46  forms a curved or arcuate shape that positions launch tube opening  24  perpendicularly relative to a longitudinal axis of body  12  and/or bail members  20 ,  26 . Launch tube  18 , or at least portion  46  of launch tube  18 , is preferably fabricated from a highly flexible material or it may be fabricated, e.g., from Nitinol tubing material which is adapted to flex, e.g., via circumferential slots, to permit bending. Alternatively, assembly  14  may be configured such that launch tube  18  is reconfigured simultaneously with the proximal withdrawal of acquisition member  30  and acquired tissue  44 .  
      The tissue wall of a body lumen, such as the stomach, typically 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 securing elements, e.g., staples or anchors, used to achieve reduction of the body lumen are preferably engaged at least through or at the muscularis tissue layer, and more preferably, the serosa layer. Advantageously, stretching of tissue fold  44  between bail members  20 ,  26  permits an anchor to be ejected through both the muscularis and serosa layers, thus enabling durable gastrointestinal tissue approximation.  
      As shown in  FIG. 2D , once launch tube opening  24  has been desirably positioned relative to the tissue fold  44 , needle assembly  48  may be advanced through launch tube  18  via manipulation from its proximal end at handle  16  to pierce preferably through a dual serosa layer through tissue fold  44 . Needle assembly  48  is preferably a hollow tubular needle through which one or several tissue anchors may be delivered through and ejected from in securing the tissue fold  44 , as further described below.  
      Because needle assembly  48  penetrates the tissue wall twice, it exits within the body lumen, thus reducing the potential for injury to surrounding organs. A detail cross-sectional view is shown in  FIG. 3A  of anchor delivery assembly  50  in proximity to tissue fold F. In this example, tissue fold F may comprise a plication of tissue created using the apparatus  10  described herein or any other tool configured to create such a tissue plication. Tissue fold F may be disposed within a gastrointestinal lumen, such as the stomach, where tissue wall W may define the outer or serosal layer of the stomach. Anchor delivery assembly  50  may generally comprise launch tube  18  and needle assembly  48  slidingly disposed within launch tube lumen  52 . Needle assembly  48  is generally comprised of needle  54 , which is preferably a hollow needle having a tapered or sharpened distal end  66  to facilitate its travel into and/or through the tissue. Other parts of the assembly, such as upper and lower bail members  20 ,  26 , respectively, and tissue acquisition member  28  have been omitted from these figures only for clarity.  
      Once launch tube  18  has been desirably positioned with respect to tissue fold F, needle  54  may be urged or pushed into or through tissue fold F via needle pushrod or member  56  from its proximal end preferably located within handle  16 . Needle  54  may define needle lumen  58  within which distal anchor  62  and/or proximal anchor  64  may be situated during deployment and positioning of the assembly. A single suture or flexible element  70  (or multiple suture elements) may connect proximal anchor  64  and distal anchor  62  to one another. For instance, element  70  may comprise various materials such as monofilament, multifilament, or any other conventional suture material, elastic or elastomeric materials, e.g., rubber, etc. Biocompatible metals may also be utilized for suture materials.  
      Needle  54  may optionally define needle slot  60  along its length to allow suture  70  to pass freely within and out of needle  54  when distal anchor  62  is ejected from needle lumen  58 . Alternatively, rather than utilizing needle slot  60 , needle  54  may define a solid structure with suture  70  being passed into needle lumen  58  via the distal opening of needle  54 .  
      The proximal end of suture  70  may pass slidingly through proximal anchor  64  to terminate in suture loop  74  via cinching knot  72 . Suture loop  74  may be omitted and the proximal end of suture  70  may terminate proximally of the apparatus  10  within control handle  16 , proximally of control handle  16 , or at some point distally of control handle  16 . In this variation, suture loop  74  may be provided to allow for a grasping or hooking tool to temporarily hold suture loop  74  for facilitating the cinching of proximal  64  and distal  62  anchors towards one another for retaining a configuration of tissue fold F, as described in further detail below. Cinching knot  72  may also comprise a slidable knot which may be slid distally along suture  70  to lock or hold against proximal anchor  64  once the tissue fold F and anchors  62 ,  64  have been desirably positioned and tensioned, as also described below in further detail.  
      After needle assembly  48  has been pushed distally out through launch tube opening  24  and penetrated into and/or through tissue fold F, as shown in  FIG. 3B , anchor pushrod or member  68  may be actuated also via its proximal end to eject distal anchor  62 , as shown in  FIG. 3C . Once distal anchor  62  has been ejected distally of tissue fold F,  FIG. 3D  shows how needle  54  may be retracted back through tissue fold F by either retracting needle  54  back within launch tube lumen  52  or by withdrawing the entire anchor delivery assembly  50  proximally relative to tissue fold F.  
       FIG. 3E  shows that once needle  54  has been retracted, proximal anchor  64  may then be ejected from launch tube  18  on a proximal side of tissue fold F. With both anchors  62 ,  64  disposed externally of launch tube  18  and suture  70  connecting the two, proximal anchor  64  may be held against the distal end of launch tube  18  and urged into contact against tissue fold F, as shown in  FIGS. 3F and 3G , respectively. As proximal anchor  64  is urged against tissue fold F, proximal anchor  64  or a portion of suture  70  may be configured to provide any number of directionally translatable locking mechanisms which provide for movement of an anchor along suture  70  in a first direction and preferably locks, inhibits, or prevents the reverse movement of the anchor back along suture  70 . In other alternatives, the anchors may simply be delivered through various elongate hollow tubular members, e.g., a catheter, trocars, etc.  
      Referring now to  FIG. 4 , it may be desirable to approximate multiple tissue folds, such as posterior and anterior folds within a patient&#39;s stomach to partition the stomach and create a restriction that limits the passage of food therethrough.  FIG. 4  illustrates approximation of fold F 1  and fold F 2 . The folds illustratively are secured with a securing element comprising basket-type anchor assembly  80  having distal basket  82  and proximal basket  84  connected by suture  70 . When folds F 1  and F 2  comprise gastrointestinal tissue folds formed from the interior of the GI lumen, upon approximation of the tissue folds, the folds contact each other along adjacent regions of mucosal tissue M. However, the mucosal tissue typically will not heal together along the contacting tissue interface. Thus, a securing element, such as anchor assembly  80 , may be required to maintain approximation of folds F 1  and F 2 .  
       FIGS. 1-4  have illustrated exemplary methods and apparatus for forming, securing and approximating tissue folds. However, these methods and apparatus are provided only for the sake of illustration and in no way should be construed as limiting. Furthermore, with respect to the securing elements and anchor assemblies described herein, the types of anchors shown and described are intended to be illustrative and are not limited to the variations shown. For instance, “T”-type tissue anchors have been shown, as well as reconfigurable “basket”-type anchors, which may generally comprise a number of configurable struts or legs extending between at least two collars or support members. Other variations of these or other types of anchors are also contemplated for use in securing tissue folds. Examples of such securing elements are disclosed 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. Moreover, a single type of anchor may be used exclusively in an anchor assembly; alternatively, a combination of different anchor types may be used in an anchor assembly. Furthermore, the different types of cinching or locking mechanisms are not intended to be limited to any of the particular variations shown and described but may be utilized in any of the combinations or varying types of anchors as practicable.  
      With reference now to  FIG. 5 , achieving prolonged maintenance of approximated tissue folds by promoting healing of the folds along the regions of mucosal contact is preferably achieved utilizing methods and apparatus described herein. Such healing may comprise remodeling the tissue folds. For example, opposing mucosal tissue in contact along each fold may be abraded, burnt, ablated, charred, irritated or otherwise injured, and preferably removed, to initiate a wound healing response that remodels the tissue and results in scar tissue formation with concomitant fusion of each fold at region(s) of opposing mucosal tissue contact. Such injury and/or removal of mucosal tissue may, for example, be achieved via electromagnetic, thermal, chemical, biologic or mechanical modalities, or a combination thereof. Additional injury/removal modalities will be apparent to those of skill in the art.  
      During the period of time necessary for remodeling and/or scar tissue formation, securing elements, such as those previously described, may be utilized to maintain contact of opposing injured tissue along each tissue fold. The securing elements optionally may be removed or may biodegrade upon formation of scar tissue. Alternatively, the elements may be left in place indefinitely to reinforce the scar tissue and facilitate prolonged maintenance of the tissue folds. However, upon formation of the scar tissue, the securing elements need no longer solely maintain the folds.  
       FIG. 5  illustrates healing and remodeling of the approximated tissue folds along the regions of contact M between approximated tissue folds F 1  and F 2 . By injuring, and preferably removing, mucosal tissue along the contact regions, the folds have fused together. Such injury and/or removal of mucosal tissue may be achieved before, during and/or after approximation of folds F 1  and F 2 . By healing and fusing together, the approximated folds may no longer be solely dependent on additional securing element(s), for example, anchor assembly  80  of  FIG. 4 , to maintain their approximation.  
      In  FIG. 5 , the securing element(s) illustratively have been removed or have biodegraded from the tissue folds, and approximation of the folds is solely maintained via tissue remodeling/scar tissue formation. However, it should be understood that securing element(s) alternatively may be left in place to reinforce the remodeled scar tissue that fuses folds F 1  and F 2 . In this manner, the securing element(s) and the scar tissue may share the burden of maintaining approximation and may also act as redundant safety mechanisms to maintain tissue fold approximation, should either the remodeled tissue or the securing element(s) fail.  
      The method of  FIG. 5  may, for example, comprise the steps of forming at least two tissue folds at a target tissue region, injuring or removing tissue disposed between the at least two tissue folds, and approximating the at least two tissue folds such that the at least two tissue folds contact one another in a region of injured or removed tissue, thereby promoting healing between the at least two tissue folds. The method may also comprise providing a shape-lockable device, endoluminally advancing the shape-lockable device to a target tissue region, then shape-locking the device and advancing instruments along or through the shape-lockable device to form the tissue folds. The instruments/tools alternatively may be coupled to, or integrated into, the shape-lockable device.  
      Referring now to  FIG. 6 , a method of utilizing the remodeling technique of  FIG. 5  to perform an illustrative medical procedure is described. In  FIG. 6 , stomach S comprises a series of adjacent approximated and remodeled tissue folds F that partition the stomach into first and second lumens over at least a portion of its length. The partitioned stomach is expected to restrict or reduce the passage of food therethrough, thereby promoting weight loss in obese or morbidly obese patients. Additional medical procedures utilizing apparatus and methods of the present invention, such as the treatment of gastroesophageal reflux disease (“G.E.R.D.”), will be apparent.  
      The method of  FIG. 6  may comprise the steps of forming anterior and posterior tissue folds within a patient&#39;s stomach in a vicinity of the patient&#39;s gastroesophageal junction, injuring, and preferably removing, tissue disposed between the anterior and posterior tissue folds, approximating the anterior and posterior tissue folds such that the approximated tissue folds contact one another in a region of injured and/or removed tissue, thereby promoting healing between the at least two tissue folds, and repeating the method at at least one adjacent location within the patient&#39;s stomach to partition and reduce the patient&#39;s stomach. The method preferably is performed endoluminally, but additionally or alternatively may be performed per-orally, transgastrically, laparoscopically, intraluminally, etc.  
      With reference to  FIG. 7 , an injury tool for locally injuring or removing mucosal tissue to promote healing is described. In a first variation, injury tool  100  comprises ablation element  110 . Ablation element  110  may, for example, comprise a monopolar or bipolar Radio Frequency (“RF”) ablation element, and illustratively is proximally coupled to RF generator  200  for energizing the ablation element. Element  110  may be brought into contact with mucosal tissue M of  FIGS. 4 and 5 , and then energized to ablate or otherwise injure and/or remove the mucosal tissue to initiate a wound healing response for fusing the approximated folds together. Ablation element  110  of injury tool  100  may, for example, comprise a commercially available RF probe, such as the Gold Probe™ Electrohemostasis Catheter from the Boston Scientific Corporation of Natick, Mass.  
      Injury tool  100  may be used in combination with apparatus for forming, securing and approximating tissue folds. For example, the tool may be integrated into tissue manipulation assembly  14  of  FIGS. 1 and 2 . Alternatively, the tool may be advanced through body  12  of plication assembly  10 . Furthermore, tool  100  optionally may be provided as part of a system of tools, which may, for example, include plication assembly  10  and/or overtube  1 .  
      With reference to  FIGS. 8 , additional methods of utilizing injury tool  100  are described. As seen in  FIG. 8A , the tool may be advanced through overtube  1  for injuring mucosal tissue M of tissue folds F. Overtube  1  may, for example, comprise multiple lumens for advancing tool  100  adjacent to assembly  14  as shown. The injured mucosal tissue M will be in contact upon approximation of folds F, which is expected to cause remodeling and fusion of the folds together.  FIG. 8B  illustrates an alternative method whereby contacting mucosal tissue M is injured after approximation of the folds. Injuring the tissue post-approximation may decrease a risk of injuring the tissue in an improper location.  
      Referring now to  FIGS. 9 , additional variations of injury tool  100  are described. As seen in  FIG. 9A , tool  100  may comprise elongated injury element  120 . Element  120  may, for example, comprise an energizable electrode for ablating the mucosa, or may comprise a cutting element for mechanically injuring or removing the mucosa. As yet another alternative, element  120  may comprise both an energizable electrode and a cutting element. Element  120  may, for example, be about 1 cm (about 0.4 in.) long and about 0.008-0.013 cm (about 0.003-0.005 in.) thick, though any alternative dimensions may be provided. Element  120  illustratively is proximally connected to previously described RF generator  200 .  
       FIG. 9B  illustrates another variation of tool  100  and element  120  having suction element  130 . Suction element  130  is coupled to suction pump  300 . Elements  120  and  130  may be used in combination to remove mucosal tissue. For example, element  120  may ablate or cut the mucosal tissue, while suction drawn through element  130  via pump  300  may remove the ablated or cut tissue. Suction element  130  may also be used to engage tissue prior to injury.  
       FIG. 9C  provides still another variation of tool  100  and element  120  comprising fluid injection element  140 . Element  140  may be used to inject saline or other fluids, e.g., for cooling tissue ablated with element  120  and/or to cleanse tissue ablated or cut with the element. Additionally or alternatively, abrasive chemicals may be injected through element  140  to injure the mucosa.  
      As seen in  FIG. 9D , injury tool  100  may comprise removal element  150 , which may comprise edge  152  that may be translated relative to injury element  120  to slough off mucosal tissue injured by the element. The sloughed off tissue may be allowed to simply pass, e.g., through the patient&#39;s GI system. Alternatively, as seen in  FIG. 9E , tool  100  may further comprise capture element or compartment  160  for capturing removed tissue. Removal of injured tissue may accelerate or enhance the wound healing response and/or may increase the tenacity of bonding between contacting tissue surfaces.  
       FIG. 9F  depicts a variation of tool  100  and element  120  comprising depth-limiting element  170 . The distance D between injury element  120  and depth-limiting element  170  may be specified to provide a maximum depth to which injury of mucosal tissue may occur. Such a depth-limiting feature may be used to ensure that injury is inflicted upon the tissue only to specified layers, e.g., the mucosal and/or muscularis layers of tissue. For example, distance D may comprise a distance of about 5 mm (about 0.2 in.), though any alternative distance may be provided. When injury element  120  comprises a mechanical cutting element, the maximum depth of injury is expected to approximate distance D. When the injury element comprises an ablation element, the depth will depend upon both distance D and the parameters of ablation energy passed through element  120 , as well as characteristics of the tissue being ablated.  
      Referring now to  FIG. 10 , additional variations of tool  100  are described comprising mechanical injury element  180 having injury tip  182  coupled to rotating shaft  184 . Shaft  184  preferably is proximally coupled to motor  400 . In  FIG. 10A , injury tip  182  comprises elongated element  186  that extends substantially perpendicular to rotating shaft  184 . Element  186  preferably comprises a polymeric or metal wire or fiber. When shaft  184  is rotated with significant velocity, mucosal tissue ‘whipped’ by element  186  is injured to initiate the healing response. In  FIG. 10B , alternative injury tip  182  comprises burr  188  having rough or abrasive surface  189 . When rotated against tissue, the abrasive surface injures the tissue.  
      Injury tool  100  preferably is used in combination with additional tools, e.g., for forming and securing gastrointestinal tissue folds, such as plication assembly  10  and/or overtube  1 . More generally, the additional tools may comprise tools for accessing, visualizing, grasping, maneuvering, piercing, folding, plicating, approximating, securing, characterizing, sampling and/or suturing GI tissue. One or more of the tools optionally may be steerable and/or shape-lockable/rigidizable. Additional tools will be apparent to those of skill in the art. Such tools may be provided as a kit or system in combination with the injury tool. Furthermore, the injury tool may be integrated into multi-functional tools. The tools preferably are configured for endoluminal passage within a patient&#39;s GI tract.  
      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.