Patent Publication Number: US-8992420-B2

Title: Methods and apparatus for off-axis visualization

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 11/365,088, filed Feb. 28, 2006, and now pending, which is a continuation-in-part of U.S. patent application Ser. No. 11/129,513 filed May 13, 2005 and now abandoned. U.S. patent application Ser. No. 11/129,513 is a continuation-in-part of U.S. patent application Ser. No. 10/824,936 filed Apr. 14, 2004, now pending, and also claims priority to U.S. Provisional Patent Application No. 60/670,426 filed Apr. 11, 2005. Each of these applications is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to methods and apparatus for performing endoluminal procedures within a body lumen. More particularly, the present invention relates to methods and apparatus for visualizing and/or performing procedures endoluminally within a body lumen utilizing off-axis articulation and/or visualization. 
     Medical endoscopy entails the insertion of an elongate body into a body lumen, conduit, organ, orifice, passageway, etc. The elongate body typically has a longitudinal or working axis and a distal region, and a visualization element disposed near the distal region in-line with the working axis. The visualization element may comprise an optical fiber that extends through the elongate body, or a video chip having an imaging sensor, the video chip coupled to or including a signal-processing unit that converts signals obtained by the imaging sensor into an image. The elongate body may also include a working lumen to facilitate passage of diagnostic or therapeutic tools therethrough, or for injection of fluids or to draw suction. 
     The maximum delivery profile for a medical endoscope may be limited by the cross-sectional profile of the body lumen, conduit, organ, orifice, passageway, etc., in which the endoscope is disposed. At the same time, advances in therapeutic endoscopy have led to an increase in the complexity of operations attempted with endoscopes, as well as the complexity of tools advanced through the working lumens of endoscopes. As tool complexity has increased, a need has arisen in the art for endoscopes having relatively small delivery profiles that allow access through small body lumens, but that have relatively large working lumens that enable passage of complex diagnostic or therapeutic tools. Furthermore, as the complexity of operations attempted with endoscopes has increased, there has arisen a need for enhanced visualization platforms, including three-dimensional or stereoscopic visualization platforms. 
     As with endoscopy, ever more challenging procedures are being conducted utilizing laparoscopic techniques. Due to, among other factors, the profile of instruments necessary to perform these procedures, as well as a need to provide both visualization and therapeutic instruments, laparoscopic procedures commonly require multiple ports to obtain the necessary access. Multiple ports also may be required due to the limited surgical space accessible with current, substantially rigid straight-line laparoscopic instruments. 
     Moreover, conventional endoscopes and instruments provide generally inadequate platforms to perform complex surgeries within patient bodies. The flexible nature of conventional endoscopes and the structural weakness and functional limitations of the instruments passed through small channels within the endoscopes make vigorous tissue manipulation and organ retraction extremely difficult. 
     Instruments pushed distally through a retroflexed gastroscope, for example, simply push the unsupported endoscope away from the target tissue. As the instrument is further advanced against the tissue surface, the endoscope is typically flexed or pushed away from the tissue region due to a lack of structural rigidity or stability inherent in conventional endoscopes. 
     Endoscopic surgery is further limited by the lack of effective triangulation due in part to a 2-dimensional visual field typically provided by an endoscope which limits depth perception within the body lumen. Moreover, conventional endoscopic procedures are generally limited to instruments which allow only for co-axial force exertion along a longitudinal axis of the endoscope and instruments which have an inability to work outside of the endoscopic axis. 
     In view of the foregoing, it would be desirable to provide methods and apparatus for performing endoluminal procedures that facilitate introduction of the apparatus into relatively small body lumens, while providing for introduction of at least one relatively large tool, as compared to standard endoscopes or laparoscopes. It also would be desirable to provide methods and apparatus that facilitate single port laparoscopy. 
     BRIEF SUMMARY OF THE INVENTION 
     The endoluminal tissue treatment assembly described herein may comprise, in part, a flexible and elongate body which may utilize a plurality of locking links which enable the elongate body to transition between a flexible state and a rigidized or shape-locked configuration. Details of such a shape-lockable body may be seen in further detail in U.S. Pat. Nos. 6,783,491; 6,790,173; and 6,837,847, each of which is incorporated herein by reference in its entirety. 
     Additionally, the elongate body may also incorporate additional features that may enable any number of therapeutic procedures to be performed endoluminally. An elongate body may be accordingly sized to be introduced per-orally. However, the elongate body may also be configured in any number of sizes, for instance, for advancement within and for procedures in the lower gastrointestinal tract, such as the colon. 
     The assembly, in one variation, may have several separate controllable bending sections along its length to enable any number of configurations for the elongate body. For instance, in one variation, elongate body may further comprise a bending section located distal of the elongate body; the bending section may be configured to bend in a controlled manner within a first and/or second plane relative to the elongate body. In yet another variation, the elongate body may further comprise another bending section located distal of the first bending section. In this variation, the bending section may be configured to articulate in multiple planes, e.g., 4-way articulation, relative to the first bending section and elongate body. In a further variation, a third bending section may also be utilized along the length of the device. 
     In yet another variation, each of the bending sections and the elongate body may be configured to lock or shape-lock its configuration into a rigid set shape once the articulation has been desirably configured. An example of such an apparatus having multiple bending sections which may be selectively rigidized between a flexible configuration and a shape-locked configuration may be seen in further detail in U.S. Pat. Pubs. 2004/0138525 A1; 2004/0138529 A1; 2004/0249367 A1; and 2005/0065397 A1, each of which is incorporated herein by reference in its entirety. 
     As the bending sections may be articulated in any number of configurations via control wires routed through the elongate body, the assembly may be actively steered to reach all areas of the stomach, including retroflexion to the gastroesophageal junction. The assembly may also be configured to include any number of features such as lumens defined through the elongate body for insufflation, suction, and irrigation similar to conventional endoscopes. 
     Once a desired position is achieved within a patient body, the elongate body may be locked in place. After insertion and positioning, the distal end of a visualization lumen can be elevated above or off-axis relative to the elongate body to provide off-axis visualization. The off-axis visualization lumen may be configured in any number of variations, e.g., via an articulatable platform or an articulatable body to configure itself from a low-profile delivery configuration to an off-axis deployment configuration. The visualization lumen may define a hollow lumen for the advancement or placement of a conventional endoscope therethrough which is appropriately sized to provide off-axis visualization during a procedure. 
     Alternatively, various imaging modalities, such as CCD chips and LED lighting may also be positioned within or upon the lumen. In yet another alternative, an imaging chip may be disposed or positioned upon or near the distal end of lumen to provide for wireless transmission of images during advancement of the assembly into a patient and during a procedure. The wireless imager may wirelessly transmit images to a receiving unit located externally to a patient for visualization. Various examples of various articulatable off-axis visualization platforms may be seen in further detail in U.S. patent application Ser. No. 10/824,936 filed Apr. 14, 2004, which is incorporated herein by reference in its entirety. 
     In addition to the off-axis visualization, an end effector assembly having one or more articulatable tools, e.g., graspers, biopsy graspers, needle knives, snares, etc., may also be disposed or positioned upon or near the distal end of the assembly. The tools may be disposed respectively upon a first and a second articulatable lumen. Each of the articulatable lumens may be individually or simultaneously articulated with respect to bending section and the off-axis lumen and any number of tools may be advanced through the assembly and their respective lumens. During advancement endoluminally within the patient body, tools may be retracted within their respective lumens so as to present an atraumatic distal end to contacted tissue. Alternatively, tools may be affixed upon the distal ends of lumens and atraumatic tips may be provided thereupon to prevent trauma to contacted tissue during endoluminal advancement. 
     Any number of lumens, articulatable or otherwise, may be utilized as practicable. Examples of articulatable lumens are shown in further detail in U.S. Pat. Pubs. 2004/0138525 A1; 2004/0138529 A1; 2004/0249367 A1; and 2005/0065397 A1, each of which have been incorporated by reference above. 
     The utilization of off-axis visualization and off-axis tool articulation may thereby enable the effective triangulation of various instruments to permit complex, two-handed tissue manipulations. The endoluminal assembly may accordingly be utilized to facilitate any number of advanced endoluminal procedures, e.g., extended mucosal resection, full-thickness resection of gastric and colonic lesions, and gastric remodeling, among other procedures. Moreover, the endoluminal assembly may be utilized in procedures, e.g., trans-luminal interventions to perform organ resection, anastomosis, gastric bypass or other surgical indications within the peritoneal cavity, etc. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an illustrative view of one variation of an endoluminal tissue treatment assembly having a handle, an optionally rigidizable elongate body, and an end effector assembly with articulatable off-axis tool arms and articulatable off-axis visualization. 
         FIGS. 2A and 2B  show illustrative perspective views of a variation of the end effector assembly in a deployed configuration and a low-profile delivery configuration, respectively. 
         FIG. 3  shows a side view of the end effector assembly of  FIGS. 2A and 2B . 
         FIGS. 4A and 4B  illustrate a typical view of the articulatable off-axis tool arms performing a procedure on a tissue region of interest from the perspective of the off-axis visualization lumen. 
         FIG. 5  illustrates another variation of the off-axis visualization lumen in one deployed configuration. 
         FIG. 6  shows another variation of the end effector assembly in which the off-axis visualization assembly may be utilized with at least one articulatable off-axis tool arm. 
         FIG. 7  shows another variation of the end effector assembly in which an inflatable balloon may be utilized for providing an atraumatic surface during low-profile advancement of the end effector. 
         FIG. 8  shows another variation in which a cap may be utilized at the distal end of the assembly to provide an atraumatic surface for low-profile advancement. 
         FIG. 9  shows yet another variation of the off-axis visualization lumen in which an articulatable lumen disposed upon a reconfigurable platform may be configured such that visualization of the tissue region of interest directly beneath the imager may be provided. 
         FIG. 10  shows yet another variation of the off-axis visualization lumen attached to the distal end of the elongate body. 
         FIG. 11  illustrates an exploded assembly view of one variation for the tool arms. 
         FIG. 12  illustrates a side view of the tool arms in a deployed configuration. 
         FIGS. 13A to 13D  illustrate possible movements of the articulatable off-axis tool arms relative to the elongate body. 
         FIG. 14  illustrates the possible longitudinal advancement of at least one tool arm relative to the elongate body. 
         FIG. 15  illustrates the possible rotational motion of at least one tool arm about its longitudinal axis relative to the elongate body. 
         FIG. 16  illustrates some of the possible articulation of the tool arms relative to one another. 
         FIGS. 17A and 17B  illustrate one example for advancing an elongate body transesophageally into the stomach for performing a procedure. 
         FIGS. 18A to 18C  illustrate another variation of the elongate body having two adjacent sections which are articulatable relative to each other and which are also optionally rigidizable to retain a desired configuration. 
         FIGS. 18D and 18E  illustrate yet another variation of the elongate body having three adjacent sections which are all articulatable relative to each other and which are also optionally rigidizable to retain a desired configuration. 
         FIGS. 18F to 18H  illustrate an example of a three-sectioned variation of the elongate body being advanced transesophageally into the stomach and articulated to position its distal end near or adjacent to the gastroesophageal junction. 
         FIG. 18I  illustrates another example of  FIGS. 18F to 18H  in which at least one the bendable sections may be articulated in an opposing direction relative to the remaining two bendable sections to further articulate the elongate body within the stomach. 
         FIG. 19  shows an end view of one variation of the cross-section of the elongate body providing two lumens for their respective tool arms and a single lumen for the visualization apparatus or endoscope. 
         FIGS. 20A and 20B  show end and side views of an example of an individual link through which the working lumens may be positioned. 
         FIGS. 21A and 21B  show other variations of the cross-section of the elongate body providing two lumens for their respective tool arms, a lumen for visualization, and an auxiliary lumen for an additional instrument to be passed therethrough. 
         FIG. 21C  shows a perspective view of an example for lumen positioning relative to one another for the configuration of  FIG. 21A . 
         FIGS. 22A and 22B  show perspective detail views of an example of the handle assembly optionally having a rigidizable elongate body; in a first configuration in  FIG. 22A , rigidizing control is actuated or depressed to rigidize or shapelock the elongate body and in a second configuration in  FIG. 22B  where rigidizing control may be released to place the elongate body in a flexible state. 
         FIG. 22C  shows an end view of the handle of  FIG. 22B  revealing the open lumen for the passage of tools, instruments, and/or visualization fibers, etc., therethrough. 
         FIG. 23  shows an exploded perspective view of a sealable or gasketed port assembly which may be attached to the handle for passing tools and/or instruments therethrough while maintaining a seal. 
         FIGS. 24A and 24B  illustrate perspective and partial cross-sectional side views, respectively, of yet another variation of the endoluminal tissue treatment assembly having an endoscope which may be passed through an opening in the elongate body, which is optionally rigidizable, for providing off-axis visualization. 
         FIGS. 25A and 25B  illustrate yet another variation where the articulatable sections of the elongate body may be configured to have different lengths. 
         FIG. 26  shows another variation in which the articulatable tools may be passed through an opening defined along the elongate body which also has an articulatable distal portion to provide for off-axis visualization. 
         FIGS. 27A to 27C  show yet another variation in which the tool arms may be configured to have predetermined configurations once advanced distally of the elongate body. 
         FIG. 27D  shows yet another variation in which the articulatable tool arms may be freely rotated relative to the elongate body. 
         FIG. 28  shows yet another variation in which an imaging chip, e.g., a CCD chip, may be disposed upon the end of a guidewire having a predetermined configuration to provide for visualization of the tissue region; the imaging chip may transmit its images via wire through the guidewire or wirelessly to a receiver located externally of a patient body. 
         FIG. 29  shows yet another variation in which an imaging chip may be disposed upon a pivoting member. 
         FIG. 30  shows another variation where imaging and/or lighting during a procedure may be provided via imaging capsules and/or LEDs temporarily attached within the patient body and which transmit their images wirelessly to a receiver outside the patient body. 
         FIG. 31A  shows an imaging assembly or endoscope passed through an opening or skive defined along the outer surface of an elongate body. 
         FIG. 31B  shows a cross-sectional illustration of the articulatable imaging assembly having a rotatable housing contain an imager. 
         FIGS. 32A to 32C  show an instrument utilizing a pull-wire to control the off-axis articulation of the imaging assembly. 
         FIGS. 33A and 33B  show an elongate body having a swing arm rotatably connected via a pivot to direct the positioning of the imaging assembly in an off-axis configuration. 
         FIGS. 34A and 34B  show a balloon assembly which may be configured to conform into a bent or curved configuration for positioning of the imaging assembly in an off-axis configuration. 
         FIGS. 35A and 35B  show a sleeve having a pre-formed bend or curve shape which may be wrapped or at least partially surrounded around an endoscope to position the imaging assembly in an off-axis configuration. 
         FIGS. 36A and 36B  show a sleeve made from an electro-active polymer which may be actuated to reconfigure a position of the imaging assembly. 
         FIGS. 37A and 37B  show side and end views, respectively, of a variation utilizing two or more off-axis visualization elements which are reconfigurable between a straightened and curved configuration. 
         FIGS. 38A and 38B  show another variation where two or more off-axis visualization elements may be constrained within a retractable retaining sleeve. 
         FIGS. 39A and 39B  illustrate an inflatable balloon assembly in an un-inflated and inflated state where the balloon defines one or more curved lumens therethrough for passing tools or instruments through. 
         FIG. 39C  shows a perspective view of the assembly of  FIG. 39B  with the balloon in its inflated configuration. 
         FIGS. 40A and 40B  show an endoscope or imaging assembly which may be articulated from a first off-axis position to a second off-axis position to result in an expanded field-of-view. 
         FIGS. 41A and 41B  show another variation for articulating an endoscope or imaging assembly from a first off-axis position to a proximal second off-axis position through an opening or skive along the elongate body. 
         FIG. 42  shows an example of an elongate body which utilizes multiple skives along its length. 
         FIGS. 43A and 43B  show side and partial cross-sectional side views, respectively, of an in-line imaging assembly for providing off-axis visualization utilizing a rotatable element. 
         FIGS. 44A and 44B  show partial cross-sectional side and end views, respectively, of another variation of an in-line imaging assembly utilizing one or more pivoting reflectors. 
         FIG. 45A  shows an example of a visualization enhancement where an imaging assembly may provide multiple adjacent imaging chips, e.g., CCD or CMOS. 
         FIGS. 45B to 45E  illustrate how sequential imaging, capturing, and processing of the captured images can be utilized to provide for panoramic endoluminal visualization. 
         FIG. 46  illustrates another example for image enhancement utilizing a combined fluoroscopic-endoscopic imaging system for display on a monitor and/or goggles. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Endoluminal access may be achieved more effectively by utilizing off-axis articulation with an endoluminal tissue manipulation assembly advanced within a body lumen, e.g., advanced endoluminally or laparoscopically within the body lumen. As described herein, off-axis articulating elements may act as reconfigurable platforms from which various tools and/or imagers may be advanced or therapies may be conducted. Once the assembly has been desirably situated within the body, a versatile platform from which to access, manipulate, and visualize a greater portion of the body lumen may be deployed from a device having a relatively small delivery profile. 
     With reference to  FIG. 1 , the endoluminal tissue manipulation  10  assembly as described herein may comprise, at least in part, a distal end effector assembly  12  disposed or positionable at a distal end of a flexible and elongate body  14 . A handle assembly  16  may be connected to a proximal end of the elongate body  14  and include a number of features or controls for articulating and/or manipulating both the elongate body  14  and/or the distal end effector assembly  12 . 
     The elongate body  14  may optionally utilize a plurality of locking or lockable links nested in series along the length of the elongate body  14  which enable the elongate body  14  to transition between a flexible state and a rigidized or shape-locked configuration. Details of such a shape-lockable body may be seen in further detail in U.S. Pat. Nos. 6,783,491; 6,790,173; and 6,837,847, each of which is incorporated herein by reference in its entirety. Alternatively, elongate body  14  may comprise a flexible body which is not rigidizable or shape-lockable but is flexible in the same manner as a conventional endoscopic body, if so desired. Additionally, elongate body  14  may also incorporate additional features that enable any number of therapeutic procedures to be performed endoluminally. Elongate body  14  may be accordingly sized to be introduced per-orally. However, elongate body  14  may also be configured in any number of sizes, for instance, for advancement within and for procedures in the lower gastrointestinal tract, such as the colon. 
     Elongate body  14 , in one variation, may comprise several controllable bending sections along its length to enable any number of configurations for the elongate body  14 . Each of these bending sections may be configured to be controllable separately by a user or they may all be configured to be controlled simultaneously via a single controller. Moreover, each of the control sections may be disposed along the length of elongate body  14  in series or they may optionally be separated by non-controllable sections. Moreover, one, several, or all the controllable sections (optionally including the remainder of elongate body  14 ) may be rigidizable or shape-lockable by the user. 
     In the example of endoluminal tissue manipulation assembly  10 , elongate body may include a first articulatable section  24  located along elongate body  14 . This first section  24  may be configured via handle assembly  16  to bend in a controlled manner within a first and/or second plane relative to elongate body  14 . In yet another variation, elongate body  14  may further comprise a second articulatable section  26  located distal of first section  24 . Second section  26  may be configured to bend or articulate in multiple planes relative to elongate body  14  and first section  24 . In yet another variation, elongate body  14  may further comprise a third articulatable section  28  located distal of second section  26  and third section  28  may be configured to articulate in multiple planes as well, e.g., 4-way articulation, relative to first and second sections  24 ,  26 . 
     As mentioned above, one or each of the articulatable sections  24 ,  26 ,  28  and the rest of elongate body  14  may be configured to lock or shape-lock its configuration into a rigid set shape once the articulation has been desirably configured. Detailed examples of such an apparatus having one or multiple articulatable bending sections which may be selectively rigidized between a flexible configuration and a shape-locked configuration may be seen, e.g., in U.S. Pat. Pub. Nos. 2004/0138525 A1, 2004/0138529 A1, 2004/0249367 A1, and 2005/0065397 A1, each of which is incorporated herein by reference in its entirety. Although three articulatable sections are shown and described, this is not intended to be limiting as any number of articulatable sections may be incorporated into elongate body  14  as practicable and as desired. 
     Handle assembly  16  may be attached to the proximal end of elongate body  14  via a permanent or releasable connection. Handle assembly  16  may generally include a handle grip  30  configured to be grasped comfortably by the user and an optional rigidizing control  34  if the elongate body  14  and if one or more of the articulatable sections are to be rigidizable or shape-lockable. Rigidizing control  34  in this variation is shown as a levered mechanism rotatable about a pivot  36 . Depressing control  34  relative to handle  30  may compress the internal links within elongate body  14  to thus rigidize or shape-lock a configuration of the body while releasing control  34  relative to handle  30  may in turn release the internal links to allow the elongate body  14  to be in a flexible state. Further examples of rigidizing the elongate body  14  and/or articulatable sections may again be seen in further detail in U.S. Pat. Pub. Nos. 2004/0138525 A1, 2004/0138529 A1, 2004/0249367 A1, and 2005/0065397 A1, incorporated above by reference. Although the rigidizing control  34  is shown as a lever mechanism, this is merely illustrative and is not intended to be limiting as other mechanisms for rigidizing an elongate body, as generally known, may also be utilized and are intended to be within the scope of this disclosure. 
     Handle assembly  16  may further include a number of articulation controls  32 , as described in further detail below, to control the articulation of one or more articulatable sections  24 ,  26 ,  28 . Handle  16  may also include one or more ports  38  for use as insufflation and/or irrigation ports, as so desired. 
     At the distal end of elongate body  14 , end effector assembly  12  may be positioned thereupon. In this variation, end effector assembly  12  may include first tissue manipulation arm  20  and second tissue manipulation arm  22 , each being independently or simultaneously articulatable and each defining a lumen for the advancement of tools or instruments therethrough. Each of the tools or instruments may be advanced through tool ports  40  located in handle assembly  16  to project from articulatable arms  20 ,  22  and controlled from handle assembly  16  or proximal to handle assembly  16 . Alternatively, various tools or instruments may be attached or connected directly to the distal ends of arms  20 ,  22  and articulatable from handle assembly  16 . At least one of the articulatable arms  20 ,  22  may be articulatable to reconfigure from a low-profile straightened configuration to a deployed configuration where at least one of the arms  20 ,  22  is off-axis relative to a longitudinal axis of elongate body  14 . Various articulation and off-axis configurations for articulatable arms  20 ,  22  may be seen in further detail in U.S. Pat. Pub. Nos. 2004/0138525 A1, 2004/0138529 A1, 2004/0249367 A1, and 2005/0065397 A1, incorporated above by reference. 
     End effector assembly  12  may further include a visualization lumen or platform  18  which may be articulatable into a deployed configuration such that a lumen opening or distal end of visualization lumen or platform  18  is off-axis relative to the longitudinal axis of elongate body  14 , as described in further detail below. 
       FIGS. 2A and 2B  show illustrative perspective views of a variation of the end effector assembly  12  in a deployed configuration and a low-profile delivery configuration, respectively. As seen in  FIG. 2A , first and second articulatable arms  20 ,  22 , respectively, may be seen in an off-axis configuration with a first tool  42 , e.g., any conventional tool such as a Maryland dissector, Babcock graspers, etc., advanced through first tool lumen  46  within first articulatable arm  20 . Likewise, second articulatable arm  22  may have a second tool  44 , e.g., any conventional tool such as claw graspers, needle knife, etc., advanced through second tool lumen  48  within second articulatable arm  22 . First and second tools  42 ,  44  may be articulated separately or simultaneously for tissue manipulation and advanced freely distally and proximally through their respective tool lumens  46 ,  48 . 
     Visualization lumen or platform  18  may also be seen in  FIG. 2A  articulated into its off-axis configuration relative to elongate body  14 . Visualization lumen opening  50  defined at the distal end of visualization platform  18  may be seen articulated into an off-axis configuration which directs visualization opening  50  such that the field-of-view provided therefrom is directly over or upon an area occupied by the articulated tool arms  20 ,  22  and respective tools  46 ,  48 . Visualization from platform  18  may be provided by any number of different methods and devices. In a first example, visualization may be provided by an endoscope  56  having imaging capabilities advanced through elongate body  14  and through visualization platform  18 . Imaging endoscope  56  may be advanced distally to project from lumen opening  50  or it may be positioned within visualization platform  18  such that its distal end is proximal of or flush with lumen opening  50 . Alternatively, imaging electronics such as CCD imaging chips or any other number of imaging chips may be positioned within visualization platform  18  to provide images of the field-of-view. These electronic images may be transmitted through wires proximally through elongate body  14  or they may alternatively be transmitted wirelessly to a receiver located externally of the patient body, as described below in further detail. 
       FIG. 2B  shows the end effector assembly  12  in a low-profile configuration for endoluminal advancement through a patient body. An atraumatic distal tip  54  may be provided over the distal end of elongate body  14  and separate atraumatic distal tips  52  may also be provided as well over the distal ends of first and second articulatable tool arms  20 ,  22 . 
       FIG. 3  shows a side view of the end effector assembly  12  of the apparatus of  FIG. 2A . As illustrated, first and second tools  42 ,  44  may be withdrawn into their respective tool lumens  46 ,  48  during endoluminal advancement of elongate body  14  through the patient and advanced through tool lumens  46 ,  48  prior to or after articulation of arms  20 ,  22 . Likewise with visualization platform  18 , if a visualization endoscope is advanced therethrough, endoscope  56  may be positioned within platform  18  during endoluminal advancement of elongate body  14  or after platform  18  has been articulated. 
       FIGS. 4A and 4B  show an example of the image which an off-axis visualization platform  18  may provide during a tissue manipulation procedure. As seen in  FIG. 4A , the visualization image  60  as may be seen on a monitor by the physician during a procedure provides for an off-axis view of the tissue region of interest as well as first and second tools  42 ,  44  and articulatable arms  20 ,  22 . Such an “overhead” perspective enables the physician to gain an overview of the tissue region of interest during a procedure and facilitates the procedure by further enabling the physician to triangulate the location of the tools  42 ,  44  with respect to the tissue. Accordingly, manipulation of first tissue region  64  and second tissue region  66  may be readily accomplished by the physician while viewing the tissue region from off-axis platform  18 . As seen in the visualization image  62  in  FIG. 4B , the tissue regions  64 ,  66  may be manipulated by articulatable tool arms  20 ,  22 , even when the tissue regions are approximated towards one another; such tissue manipulation and visualization would generally be extremely difficult, if not impossible, using conventional endoscopic devices and tools which are typically limited to straight-line tools and obstructed views typically afforded conventional endoscopes. The utilization of off-axis visualization and off-axis tool articulation may thereby enable the effective triangulation of various instruments to permit complex, two-handed tissue manipulations. 
     The end effector assembly  12  may accordingly be utilized to facilitate any number of advanced endoluminal procedures, e.g., extended mucosal resection, full-thickness resection of gastric and colonic lesions, and gastric remodeling, among other procedures. Moreover, assembly  10  may be utilized in procedures, e.g., trans-luminal interventions to perform organ resection, anastomosis, gastric bypass or other surgical indications within the peritoneal cavity, etc. 
     Referring now to  FIG. 5 , another variation is described wherein the articulating element comprises a steerable shaft. Visualization assembly  70  may generally comprise elongate body  72  having longitudinal axis W, distal region  73  and lumen  74 . As mentioned above, elongate body  72  may comprise a rigidizable and/or articulatable body or it may comprise a passively flexible body. Assembly  70  further may further comprise articulating element or platform  80  disposed near distal region  73  of elongate body  72 . Platform  80  may be coupled to the elongate body by linkages  96   a ,  96   b  rotatably disposed between hinges  92   a ,  94   a  and  92   b ,  94   b , respectively. Articulating platform  80  via hinges  92   a ,  94   a  and  92   b ,  94   b  may allow for lumens or lumen  74  to be unobstructed with the platform  80  articulated away from the openings. Visualization assembly  70  may be seen in further detail in U.S. patent application Ser. No. 10/824,936, which has been incorporated herein above by reference. 
     Articulating platform  80  may further comprise articulatable visualization lumen  82 . Visualization lumen  82  may be passively articulatable or, alternatively, may be actively controllable. Any number of conventional methods may be utilized to articulate the shape and configuration of lumen  82 . In  FIG. 5 , lumen  82  illustratively may, for example, be steerable in any number of directions. In this variation, lumen  82  may be steerable in at least four directions, e.g., via four control wires routed through or along cable  84  and elongate body  72  to a proximal region of assembly  70  for manipulation by a medical practitioner. Cable  84  may also be used to articulate platform  80 . The control wires for steerable lumen  82  may be routed through or along body  72  in spaces that would not be usable as working lumens or for tool insertion. 
     During delivery, articulating platform  80  and steerable lumen  82  are typically aligned with axis W of elongate body  72 . Advantageously, the ability to articulate platform  80  off-axis post-delivery allows assembly  70  to have both a large working lumen  74  and a small collapsed delivery profile. Furthermore, steerable platform  82  gives the assembly an off-axis platform with added functionality for performing complex procedures. The steering capability of lumen  82  may be used to steer therapeutic or diagnostic tools, and/or for illumination, visualization, fluid flushing, suction, etc., into better position for conducting such procedures. 
     Various methods and apparatus for controlling elements used in conjunction with lumen  82  may be routed through cable  84  along with the control wires for lumen  82 . For example, when a visualization element is coupled to steerable shaft  82 , electrical wires may run through cable  84  for sending and/or receiving signals, power, etc., to/from the visualization element. In such a variation, the visualization element would allow direct visualization during insertion within a body lumen, while providing off-axis visualization and steering, as well as facilitating tool introduction, post-articulation. Alternatively or additionally, when a working lumen is disposed through steerable lumen  82 , cable  84  may comprise a lumen for connecting the shaft lumen to a lumen extending through elongate body  72  of assembly  70  through which any number of visualization instruments may be advanced through. 
     Alternatively or additionally, various imaging modalities, such as CCD chips and LED lighting may also be positioned within or upon lumen  82 . In yet another alternative, an imaging chip may be disposed or positioned upon or near the distal end of lumen  82  to provide for wireless transmission of images during advancement of assembly  70  into a patient and during a procedure. The wireless imager may wirelessly transmit images to a receiving unit RX located externally to a patient for visualization. 
     Referring now to  FIG. 6 , an alternative variation of assembly  70  is shown comprising multiple articulating elements having steerable shafts. Assembly  70 ′ may comprise first articulating platform  80   a  and second articulating platform  80   b . Platform  80  may comprise first steerable lumen  82   a  and second steerable lumen  82   b , respectively. Lumens  74   a  and  74   b  extend through elongate body  72 ′ and are exposed upon articulation of platform  80   a  and  80   b , respectively. As will be apparent, a single lumen or more than two lumens alternatively may be provided. Likewise, more than two articulating elements and/or steerable shafts optionally may be provided. 
     First steerable lumen  82   a  illustratively is shown with working lumen  86  that extends through the lumen, as well as through cable  84   a  and elongate body  72 ′. Exemplary grasper tool  90  is shown advanced through lumen  86 . Second steerable lumen  82   b  illustratively is shown with visualization element  88 , as previously described, coupled to an end thereof. Electrical wires, e.g., for powering and transmitting signals to/from the visualization element, may be disposed within cable  84   b . As will be apparent, steerable lumens  82  may be provided with additional or alternative capabilities. In the case of visualization element  88  being a wireless imager, electrical wires may be omitted altogether. 
     With reference to  FIGS. 7 and 8 , illustrative embodiments of atraumatic tips for use with the assembly  70  are described. As shown in  FIG. 7 , assembly  70  is shown with atraumatic tip  76 . Tip  76  provides a smooth transition between elongate body  72  and articulating platform  80  with steerable lumen  82 . Tip  76  may, for example, comprise an inflatable balloon  77  that may be inflated as shown during insertion and delivery of assembly  70 , then deflated prior to articulation of platform  80  and off-axis steering of lumen  82 , so as not to block or impede articulation or the distal opening of the lumen  74  post-articulation. 
     In  FIG. 8 , assembly  100  may comprise an alternative atraumatic tip  78  having cap  79 , which optionally may be fabricated from rubber. Cap  79  may be U-shaped to both provide a smooth transition between elongate body  102  and articulating platform  106  in the delivery configuration, as well as to ensure that the cap does not block or impede lumen  104  post-articulation. 
       FIGS. 9 and 10  show additional alternative configurations of the articulatable platform and visualization lumen. Articulatable visualization lumen  110  may be manipulated to articulate in an off-axis configuration such that visualization lumen opening  112  is directed to face in a direction which is off-axis relative to a longitudinal axis of elongate body  72  and which is also perpendicular relative to the longitudinal axis. Although visualization lumen  110  may be articulated to face any number of directions, such a configuration may allow for a visualization element positioned within opening  112  to directly face over or upon the tissue region of interest, if so desired. 
     As shown in  FIG. 9 , visualization lumen  110  may be positioned upon platform  80  and articulated via linkages  96   a ,  96   b , as described above. Alternatively, visualization lumen  110  may also be directly attached via interface  114  to elongate body  72  and articulated therefrom, also as described above. 
     Turning now to the elongate body,  FIG. 11  illustrates one variation for assembly of the elongate body  120 . Distal end effector assembly  12  has been omitted merely for the sake of clarity from  FIG. 11  and following figures. The elongate body  120  may have a single lumen therethrough for a variety of uses, such as for passage of one or more instruments or for the passage of air or fluid, such as for aspiration or suction. Similarly, the elongate body  120  may have more than one lumen passing therethrough, each lumen used for a different function. 
     Further details of the elongate body construction may be seen in any of the following U.S. Pat. Pubs. 2004/0138525 A1; 2004/0138529 A1; 2004/0249367 A1; and 2005/0065397 A1, each of which is incorporated herein by reference in its entirety. 
     In some variations, elongate body  120  may include at least one instrument or tool lumen  130 , e.g. an arm guide lumen, which extends over or through at least a distal section of the elongate body  120 , typically along the majority of the length of the body  120  as shown. Here in  FIG. 11 , two arm guide lumens  130  are shown, each extending from a position along the shaft  120  near the proximal end  122  to the distal tip  126 . In addition, the elongate body  120  includes a visualization lumen  128 , which extends through the shaft  120  to the distal tip  126 . 
     In some variations, the assembly also includes at least one tool arm  132 , two are shown in  FIG. 11 , each arm  132  of which is insertable through a separate arm guide lumen  130  as indicated by the dashed lines. Each tool arm  132  has a proximal end  134 , a distal end  136  and a shaft  140  therebetween. The distal end  136  optionally is steerable, such as by manipulation of adjacent links as schematically indicated. Such steerability may be controlled by any number of methods, e.g., a steering cuff  138 , which is part of the proximal end  134 . The shaft  140  is typically flexible or deflectable to allow deflection of the surrounding elongate body shaft  120 . Each tool arm  132  may additionally include a tool deployment lumen  142  therethrough. 
     Elongate body  120  includes at least one tool  144  with two tools  144  shown in  FIG. 11 . Each tool  144  includes a distal end  146 , a proximal end  148  and an elongate shaft  150  therebetween to allow passage through the tool deployment lumen  142  of the tool arm  132 , or through lumen  130  of elongate body  120 . Each tool  144  has an end effector  152  disposed at the distal end  146  and optionally a handle  154  at the proximal end  148  for manipulation of the end effector  152  from outside the body. The tool  144  is advanced so that the end effector  152  emerges from the distal end  136  of the arm  132 , or from distal tip  126  of elongate body  120 . As will be apparent, tool  144  optionally may be formed integrally with tool arm  132 . Accordingly, rather than utilizing one or more tool arm shafts  140  insertable through elongate body  120 , articulatable distal ends  136  may alternatively be connected directly near or at the distal tip  126  of elongate body  120 . Additionally, the distal ends of tools  144  may also be connected directly to articulatable distal ends  136 . 
       FIG. 12  illustrates the assembly of  FIG. 11  in an exemplary assembled arrangement. Here, the tool arms  132  are shown inserted through the arm guide lumens  130  of the elongate body shaft  120 . The steerable distal ends  136  of the arms  132  protrude from the distal end  124  of the elongate body  120  and the proximal ends  134  of the arms  132  protrude from the proximal end  122  of the elongate body  120 . Additionally, the tools  144  are shown inserted through the tool deployment lumens  142  so that the end effectors  152  extend beyond the steerable distal ends  136  of the arms. Likewise, the proximal ends  148  of the tools  144  with handles  154  may protrude proximally from the assembly. As described above, the articulatable visualization lumen  18  or  110  (omitted from the figure for clarity) may be connected to the distal end of  124  of elongate body  120  at the location of lumen  128 . Alternatively, an endoscope used for visualization may be routed directly through lumen  128 . 
       FIGS. 13A to 13D  illustrate a series of movements of the steerable distal ends  136  of the tool arms  132 . This series serves only as an example, as a multitude of movements may be achieved by the distal ends  136  independently or together. Moreover, articulatable visualization lumen or platform  18  or  110  has been omitted from the illustrations merely for the sake of clarity.  FIG. 13A  illustrates the distal tip  126  of the elongate body  120 . The visualization lumen  128  is shown along with two arm guide lumens  130 .  FIG. 13B  illustrates the advancement of the distal ends  136  of the tool arms  132  through the arm guide lumens  130  so that the arms  132  extend beyond the distal tip  126 . 
       FIGS. 13C and 13D  illustrate deflection of the arms  132  to an exemplary arrangement.  FIG. 13C  illustrates deflection of the arms  132  laterally outward. This may be achieved by curvature in the outward direction near the base  156  of the steerable distal end  136 .  FIG. 13D  illustrates deflection of the tip section  158  of the distal end  136  laterally inward achieved by curvature in the inward direction. When an imager  162  is positioned within the lumen  128 , the tip sections  158  of the tool arms  132  and any tools  144  advanced therethrough, will be visible through the imager  162 . Additionally, when articulatable visualization lumen  18  or  110  is positioned within or connected to lumen  128 , articulation of the visualization lumen into its off-axis configuration will bring tools  132 , and in particular the distal ends  136  of tool arms  132  into the field-of-view, as described above. In  FIGS. 13C and 13D , deflection of the arms  132  may be achieved with the use of adjacent links  160  in the areas of desired curvature. 
     Variations of such links  160  and other mechanisms of deflection are described in further detail in U.S. Pat. Pubs. 2004/0138525 A1; 2004/0138529 A1; 2004/0249367 A1; and 2005/0065397 A1, each of which has been incorporated above herein by reference. Further, the deflection shown in  FIGS. 13A to 13D  are shown to be within a single plane. However, variations include deflection in multiple planes. Likewise, the arms  132  are shown to be deflected simultaneously in  FIGS. 13A to 13D , however the arms  132  may be deflected selectively or independently. 
       FIGS. 14 to 16  illustrate additional possible movements of the tool arms  132 . For example,  FIG. 14  illustrates possible axial movement of the tool arms  132 . Each tool arm  132  can independently move distally or proximally, such as by sliding within the tool deployment lumen  142 , as indicated by the arrows. Such movement may maintain the arms  132  within the same plane, yet allows more diversity of movement and therefore surgical manipulations.  FIG. 15  illustrates rotational movement of the tool arms  132 . Each tool arm  132  can independently rotate, such as by rotation of the arm  132  within the tool deployment lumen  142 , as indicated by circular arrow. Such rotation may move the arm or arms  132  through a variety of planes. By combining axial, lateral and rotational movement, the arms  132 , and therefore the tools  144  positioned therethrough (or formed integrally therewith), may be manipulated through a wide variety of positions in one or more planes. 
       FIG. 16  illustrates further articulation of the tool arms  132 . In some variations, the arms  132  may be deflectable to form a predetermined arrangement. Typically, when forming a predetermined arrangement, the arms  132  are steerable up until the formation of the predetermined arrangement wherein the arms  132  are then restricted from further deflection. In other variations, the arms  132  may be deflectable to a variety of positions and are not limited by a predetermined arrangement. Such an example is illustrated in  FIG. 16  wherein the arms  132  articulate so that the tip sections  158  curl inwardly. The tip sections  158  may be positioned in front of the lumen  128  and imager  162  for viewing or within the field-of-view provided by the off-axis articulation of visualization lumen  18  or  110  (omitted for clarity). Typically, the tip sections  158  may be positioned on opposite sides of a longitudinal axis  166  of the elongate body  120 , wherein for an imager  166  positioned within lumen  128 , in one variation, the field-of-view (indicated by arrow  164 ) may span up to, e.g., approximately 140 degrees. 
       FIGS. 17A and 17B  illustrate one example for use of the endoluminal assembly  10 .  FIG. 17A  illustrates advancement of the elongate body  120  through the esophagus E to the stomach S, as shown in  FIG. 17A . The elongate body  120  may then be steered to a desired position within the stomach S, and a tissue region of interest M may be visualized by visualization lumen or platform  18 , which may be articulated into its off-axis configuration, as shown in  FIG. 17B . Tool arms  132  may also be advanced, if not already attached directly to the distal end of elongate body  120 , through the elongate body  120  and articulated. As previously described, one or several tools  144  may be advanced through the tool arms  132 , or an end effector  152  may be disposed at the distal end of each arm  132 . In this example, a grasper  168  is disposed at the distal end of one arm  132  and a cutter  81  is disposed at the distal end of the other arm  132 , although any number of tools, e.g., graspers, biopsy graspers, needle knives, snares, etc., may be utilized depending upon the desired procedure to be performed. Moreover, the tools  144  may alternatively be affixed upon the distal ends of tool arms  132  and atraumatic tips may be provided thereupon to prevent trauma to contacted tissue during endoluminal advancement. 
     It may be appreciated that the systems, methods and devices of the present invention are applicable to diagnostic and surgical procedures in any location within a body, particularly any natural or artificially created body cavity. Such locations may be disposed within the gastrointestinal tract, urology tract, peritoneal cavity, cardiovascular system, respiratory system, trachea, sinus cavity, female reproductive system and spinal canal, to name a few. Access to these locations may be achieved through any body lumen or through solid tissue. For example, the stomach may be accessed through an esophageal or a port access approach, the heart through a port access approach, the rectum through a rectal approach, the uterus through a vaginal approach, the spinal column through a port access approach and the abdomen through a port access approach. 
     A variety of procedures may be performed with the systems and devices of the present invention. The following procedures are intended to provide suggestions for use and are by no means considered to limit such usage: laryngoscopy, rhinoscopy, pharyngoscopy, bronchoscopy, sigmoidoscopy, colonoscopy, esophagogastroduodenoscopy (EGD) which enables the physician to look inside the esophagus, stomach, and duodenum. 
     In addition, endoscopic retrograde cholangiopancreatography (ERCP) may be achieved which enables the surgeon to diagnose disease in the liver, gallbladder, bile ducts, and pancreas. In combination with this process endoscopic sphincterotomy can be done for facilitating ductal stone removal. ERCP may be important for identification of abnormalities in the pancreatic and biliary ductal system. Other treatments include cholecystectomy (removal of diseased gallbladder), CBD exploration (for common bile duct stones), appendicectomy (removal of diseased appendix), hernia repair TAP, TEPP and other (all kinds of hernia), fundoplication and HISS procedures (for gastro esophageal reflux disease), repair of duodenal perforation, gastrostomy for palliative management of late stage upper G.I.T. carcinoma), selective vagotomy (for peptic ulcer disease), splenectomy (removal of diseased spleen), upper and lower G.I. endoscopies (diagnostic as well as therapeutic endoscopies), pyloroplastic procedures (for children&#39;s congenital deformities), colostomy, colectomy, adrenalectomy (removal of adrenal gland for pheochromocytoma), liver biopsy, gastrojejunostomy, subtotal liver resection, gastrectomy, small intestine partial resections (for infarction or stenosis or obstruction), adhesions removal, treatment of rectum prolaps, Heller&#39;s Myotomy, devascularization in portal hypertension, attaching a device to a tissue wall and local drug delivery to name a few. 
     As mentioned previously, elongate body  120  has a proximal end  122  and a distal end  124  terminating in a distal tip  126 . Elongate body  120  may include one or more sections or portions of elongate body  120  in which each section may be configured to bend or articulate in a controlled manner. A first section along elongate body  120  may be adapted to be deflectable and/or steerable, shape-lockable, etc. A second section, which may be located distally of and optionally adjacent to the first section along elongate body  120 , may be adapted to retroflex independent of in conjunction with the first section. In one variation, this second section may be laterally stabilized and deflectable in a single plane. An optional third section, which may be located distally of and optionally adjacent to the second section, may be adapted to be a steerable portion, e.g., steerable within any axial plane in a 360-degree circumference around the shaft. 
     When a third section is utilized as the most distal section along elongate body  120 , such steerability may allow for movement of the distal tip of elongate body  120  in a variety of directions. Such sections will be further described below. It may be appreciated that the elongate body  120  may be comprised of any combination of sections and may include such sections in any arrangement. Likewise, the elongate body  120  may be comprised of any subset of the three sections, e.g., first section and third section, or simply a third section. Further, additional sections may be present other than the three sections described above. Furthermore, multiple sections of a given variety, e.g. multiple sections adapted to be articulated as second section above, may be provided. Finally, one or all three sections may be independently lockable, as will be described below. 
     One variation of the elongate body  120  is illustrated in  FIG. 18A  in a straightened configuration. Only elongate body  120  is shown in these illustrations and the end effector assembly with off-axis tool arms and off-axis visualization has been omitted merely for the sake of clarity. Because the elongate body  120  is used to access an internal target location within a patient&#39;s body, elongate body  120  may include a deflectable and/or steerable shaft  120 . Thus,  FIG. 18B  illustrates the elongate body  120  having various curvatures in its deflected or steered state. The elongate body  120  may be steerable so that the elongate body  120  may be advanced through unsupported anatomy and directed to desired locations within hollow body cavities. In this example, the elongate body  120  includes a first section  180  which is proximal to a second section  182 , as indicated in  FIG. 18B . Although both sections  180 ,  182  may be steerable, first section  180  may be adapted to lock its configuration while the second section  182  is further articulatable, as illustrated in  FIG. 18C  where first section  180  is shown in a locked position and the second section  182  is shown in various retroflexed positions. 
     When retroflexed, second section  182  may be curved or curled laterally outwardly so that the distal tip  126  is directable toward the proximal end  122  of the elongate body  120 . Moreover, the second section  182  may be configured to form an arc which traverses approximately 270 degrees, if so desired. Optionally, the second section  182  also may be locked, either when retroflexed or in any other position. As should be understood, first section  180  optionally may not be steerable or lockable. For example, section  180  may comprise a passive tube extrusion. 
     A further variation of elongate body  120  is illustrated in  FIG. 18D , in a straight configuration, and in  FIG. 18E , in a deflected or steered state having various curvatures. In this variation, elongate body  120  may include a first section  180  proximal to a second section  182 , which is proximal to a third section  184 . First section  180  may be flexible or semi-flexible, e.g. such that the section  180  is primarily moveable through supported anatomy, or is moveable through unsupported anatomy via one or more stiffening members disposed within or about the section. The first section  180  may be comprised of links or nestable elements which may enable the first section  180  to alternate between a flexible state and a rigidized stated. 
     Optionally, first section  180  may comprise locking features for locking the section in place while the second section  182  is further articulated. Typically, the second section  182  may be configured to be adapted for retroflexion. In retroflexion, as illustrated in  FIG. 18E , second section  182  may be curved or curled laterally and outwardly so that a portion of second section  182  is directed toward the proximal end  122  of the elongate body  120 . It may be appreciated that second section  182  may be retroflexed in any desired direction. Optionally, second section  182  may also be locked, either in retroflexion or in any other position. 
     Further, first section  180  and second section  182  may be locked in place while third section  184  is further articulated. Such articulation is typically achieved by steering, such as with the use of pullwires. The distal tip  126  preferably may be steered in any direction relative to second section  182 . For example, with second section  182  defining an axis, third section  184  may move within an axial plane, such as in a wagging motion. The third section  184  may move through any axial plane in a 360 degree circumference around the axis; thus, third section  184  may be articulated to wag in any direction. Further, third section  184  may be further steerable to direct the distal tip  126  within any plane perpendicular to any of the axial planes. Thus, rather than wagging, the distal tip  126  may be moved in a radial manner, such as to form a circle around the axis.  FIG. 18E  illustrates third section  184  steered into an articulated position within an axial plane. 
     The variation of elongate body  120  illustrated in  FIGS. 18D and 18E  having three sections  180 ,  182 ,  184  with varying movement capabilities are shown in  FIGS. 18F and 18H  in an example of positioning elongate body  120  within a stomach S through an esophagus E. Since elongate body  120  may be deflectable and at least some of the sections  180 ,  182 ,  184  may be steerable, elongate body  120  may be advanced through the tortuous or unpredictably supported anatomy of the esophagus and into the stomach S while reducing a risk of distending or injuring the organs, as shown in  FIG. 18F . Once the distal tip  126  has entered the stomach, second section  182  may be retroflexed as illustrated in  FIG. 18G . During retroflexion, distal tip  126  may traverse an arc having a continuous radius of curvature, e.g., approximately 270 degrees with a radius of curvature between about 5 to 10 cm. By retroflexing, distal tip  126  may be directed back towards first section  180  near and inferior to gastroesophageal junction GE. Second section  182  may be actively retroflexed, e.g. via pullwires, or it may be passively retroflexed by deflecting the section off a wall of stomach S while advancing elongate body  120 . 
     Second section  182  may be configured to be shape-lockable in the retroflexed configuration. The distal tip  126  may then be further articulated and directed to a specific target location within the stomach. For example, as shown in  FIG. 18H , the distal tip  126  may be steered toward a particular portion of the gastroesophageal junction GE. Third section  184  may optionally be shape-locked in this configuration. Off-axis tools and off-axis visualization may then be deployed through or from elongate body  120 , as described above, to perform any number of procedures. 
       FIG. 18I  shows yet another example in which elongate body  120  may be articulated in a manner similar as shown above in  FIG. 18H . In this variation, elongate body may comprise a first section  180  which is configured to bend or curve in any number of directions. One particular variation may configure first section  180  to articulate in a direction opposite to a direction in which second section  182  bends. This opposed articulation may result in an elongate body  120  which conforms into a question-mark shape to facilitate positioning of third section  184  within stomach S, particularly for procedures which may be performed near or at the gastroesophageal junction GE. First section  180  may be configured to automatically conform into its opposed configuration upon rigidizing elongate body  120  or it may alternatively be articulated into its configuration by the physician. 
     Turning now to the construction of the individual links which may form elongate body,  FIGS. 19 ,  20 A, and  20 B show examples of link variations which may be utilized.  FIGS. 20A and 20B  show end and side views, respectively, of one variation of a link which may be utilized for construction of elongate body  120 . An exemplary elongate body link  200  may be comprised generally of an open lumen  202  through any number of separate lumens, e.g., tool arm lumens, visualization lumens, etc., may be routed through. 
     The periphery defining open lumen  202  may define a number of openings for passage of various control wires, cables, optical fibers, etc. For instance, control wire lumens  204  may be formed at uniform intervals around the link  200 , e.g., in this example, there are four control wire lumens  204  shown uniformly positioned about the link  200 , although any number of lumens may be utilized as practicable and depending upon the desired articulation of elongate body  120 . Elongate body link  200  may also comprise a number of auxiliary control lumens  206  spaced around body link  200  and adjacent to control wire lumens  204 . Any number of biocompatible materials may be utilized in the construction of links  200 , e.g., titanium, stainless steel, etc. 
     Aside from the elongate body links  200 , one variation for a terminal link  190  may be seen in  FIG. 19 . Terminal link  190  may be utilized as an interface link between elongate body  120  and the distal end effector assembly  12 . In the variation shown in  FIG. 19 , three lumens are utilized in terminal link  190  for a visualization lumen  192  and two tool arm channels  194 ,  196 . In other variations for the terminal link, additional lumens may be defined through the link. In the case of an end effector having tools and a visualization lumen attached or coupled directly to the distal end of elongate body  120 , the off-axis tools arms and off-axis articulatable lumen may be connected directly to terminal link  190 . 
     Further examples and details of link construction may be seen in further detail in U.S. Pat. Pubs. 2004/0138525 A1; 2004/0138529 A1; 2004/0249367 A1; and 2005/0065397 A1, each of which has been incorporated above herein by reference. 
     Arrangement of the individual lumens routed through elongate body  120  may be accomplished in any number of ways. For example,  FIGS. 21A and 21B  show end views of possible lumen arrangements where four lumens are utilized through elongate body  120 . The variation in  FIG. 21A  shows elongate body link  200  where visualization lumen  192  and auxiliary instrument lumen  208  may be of a similar size diameter. Lumens  192 ,  208  may be positioned adjacently to one another with tool arm channels  194 ,  196  positioned on either side of lumens  192 ,  208 . 
     In another variation, auxiliary instrument lumen  208  may be adjacently positioned and larger than visualization lumen  192 , in which case tool arm channels  194 ,  196  may be positioned on either side of visualization lumen  192 . In the spaces or interstices through link  200  between the visualization lumen  192 , auxiliary instrument lumen  208 , or either tool arm channels  194 ,  196 , multiple smaller diameter lumens may be routed through for any number of additional features, e.g., insufflation, suction, fluid delivery, etc.  FIG. 21C  shows a perspective view of a single elongate body link  200  with visualization lumen  192 , auxiliary instrument lumen  200 , and tool arm channels  194 ,  196  routed therethrough. 
     Turning now to the handle for endoluminal assembly  10 , one variation of handle assembly may be seen in the perspective views of  FIGS. 22A and 22B . Handle assembly  16  may generally comprise, in one variation, handle  30  which is connectable to the proximal end of elongate body  120  via elongate body interface  210 . Coupling between the elongate body  120  and interface  210  may be accomplished in a number of different ways, e.g., interference fit, detents, etc., or the proximal link of elongate body  120  and interface  210  may be held adjacently to one another by routing control wires from handle  30  through interface  210  and into elongate body  120 . 
     Interface  210  may also be adapted to travel proximally or distally relative to handle  30  when rigidizing control  34  is actuated about pivot  36  to actuate a rigidized or shape-locked configuration in elongate body  120 . An example is shown in  FIG. 22A  where control  34  is depressed against handle  30  to advance interface  210  distally from handle  30 . This distal movement of interface  210  compresses the links throughout elongate body  120  to rigidize its configuration. Likewise, as shown in  FIG. 22B , when control  34  is released or pivoted away from handle  30 , interface  210  may be configured to travel proximally relative to handle  30  such that a connected elongate body  120  is released into a flexible state by decompression of its links. Further details of mechanisms and methods for link compression for actuating a rigid shape of elongate body  120  may be seen further detail in U.S. Pat. Nos. 6,783,491; 6,790,173; and 6,837,847, each of which has been incorporated by reference above. 
     Handle  30  may also define an elongate body entry lumen  212  which may be defined near or at a proximal end of handle  30 . Entry lumen  212  may define one or more openings for the passage of any of the tools and instruments, as described herein, through handle  30  and into elongate body  120 . One or more ports, e.g., ports  214 ,  216 , which are in fluid communication with one or more lumens routed through elongate body  120 , as described above, may also be positioned on handle  30  and used for various purposes, e.g., insufflation, suction, irrigation, etc. 
     Additionally, handle  30  may further include a number of articulation or manipulation controls  32  for controlling elongate body  120  and/or end effector assembly  12 . As shown in  FIGS. 22A and 22B , control assembly  32  in this variation may include a first control  218  for manipulating or articulating first section  180 ; a second control  220  for manipulating or articulating second section  182  in a first plane; and a third control  222  for manipulating or articulating second section  182  in a second plane. In this variation of handle assembly  16 , control assembly  32  is configured to have several control wheels which are adjacently positioned relative to one another over a common control axis  224 , as shown in the end view of handle assembly  16  in  FIG. 22C . Control assembly  32  may also include a locking mechanism  226  which may be configured to lock each of the controls  218 ,  220 ,  222  individually or simultaneously to lock a configuration of each section. 
     Moreover, each of the controls  218 ,  220 ,  222  may be configured to articulate their respective sections along elongate body  120  even when rigidizing control  34  has been articulated to rigidize a shape of the elongate body  120 . In alternative variations, handle assembly  16  may include additional controls for additional sections of elongate body  120 . Moreover, alternative configurations for the control assembly  32  may also include articulating levers or sliding mechanisms along handle  30  as control wheels are intended to be merely illustrative of the type of control mechanisms which may be utilized. 
     As mentioned above, entry lumen  212  may define one or more openings for the passage of any of the tools and instruments, as described herein, through handle  30  and into elongate body  120 . To manage the insertion and sealing of multiple lumens routed through handle assembly  16  and elongate body  120 , a port assembly may be connected or attached to handle  30  proximally of entry lumen  212  in a fluid-tight seal. A port assembly alignment post  228  for aligning such a port assembly may be seen in the end view of  FIG. 22C . An example of such a port assembly  230  is shown in the perspective view of  FIG. 23 . Port assembly  230  may be seen having a visualization port lumen  232  for the insertion and passage of a visualization tool, as well as tool ports  234 ,  236  on either side of visualization port lumen  232  for the insertion of tools, as described above. Auxiliary instrument port  238  may also be seen on port assembly  230 . 
     To maintain a fluid-tight seal through handle assembly  16  and elongate body  120  during instrument insertion, movement, and withdrawal in the patient body, a removable gasket  240  made from a compliant material, e.g., polyurethane, rubber, silicon, etc., may be positioned between ports  232 ,  234 ,  236 ,  238  of port assembly  230  and a retainer for securely retaining the gasket against assembly  230 . The retainer may also have ports  232 ′,  234 ′,  236 ′,  238 ′ defined therethrough for alignment with their respective ports in assembly  230  for passage of the tools or instruments. 
     Other configurations for the end effector assembly may also be made utilizing a number of variations.  FIGS. 24A and 24B  show perspective and partial cross-sectional views, respectively, of a variation of end effector assembly  250 . As illustrated, elongate body  252  may be a shape-lockable or rigidizable body which may be steerable or non-steerable, as described above, or it may generally be a passively flexible body which may be steerable or non-steerable as well. In either case, an opening  254  may be defined through an outer surface near or at a distal end of elongate body  252 . 
     A visualization assembly  256 , which may generally comprise an endoscope  258  having a bendable or flexible section  260  near or at its distal end, may be advanced through an endoscope or auxiliary instrument lumen  272  defined through elongate body  252  and advanced through opening  254 . Endoscope  258  may be advanced through opening  254  such that its flexible section  260  enables the end of endoscope  258  to be positioned in an off-axis configuration distal of elongate body  252 . Alternatively, endoscope  258  may be advanced entirely through lumen  272  such that it is disposed at the distal end of lumen  272  or projects distally therefrom to provide visualization of the tissue region of interest. First and second articulatable tool arms  262 ,  264  having one or more tools  266  upon their respective distal ends, as described above, may also be advanced through respective first and second tool lumens  268 ,  270 . Tool arms  262 ,  264  may be disposed distally of elongate body  252  such that they are within the visualization field provided by the off-axis endoscope  258 . 
     In another variation as shown in  FIGS. 25A and 25B , elongate body  274  may comprise bendable or articulatable sections of varying lengths. Elongate body  274  in this variation may be shape-lockable or rigidizable along its length, as above, or it may have a passively flexible length. For example, elongate body  252  may have a first section  276  having a length D 1  and a second section  278  having a length D 2  located distally of first section  276 . In the example shown, the length D 1  of first section  276  may be shorter than the length D 2  of second section  278 , although the length of D 1  may be longer than D 2  in another alternative. Moreover, in yet another alternative, the lengths D 1  and D 2  may be equal. In the variation shown, having a length of D 1  shorter than length D 2  may allow for the end effector assembly to be articulated into a variety of configurations, especially if first section  276  is articulated in a direction opposite to a direction in which second section  278  is articulated, as shown in  FIG. 25B . Any of the end effector assemblies described herein may be utilized with elongate body  252  having various lengths of sections  276 ,  278 . 
       FIG. 26  shows a side profile of end effector assembly  280  in yet another variation. As shown, end effector assembly  280  may have an optionally shape-lockable elongate body  282  with articulatable first section  284  and second section  286 . Second section  286  may be articulatable into an off-axis configuration such that an imager  288  positioned at its distal end may become positioned to view a region of interest accessible by first and second tool arms  292 ,  294 , which may be passed through elongate body  282  and through opening  290  defined in first section  284  into the field-of-view provided by off-axis imager  288 . Tool arms  292 ,  294  may be articulatable tool arms, as described above, or they may comprise any manner of conventional in-line tools. 
     In yet another variation,  FIGS. 27A and 27B  show perspective views of end effector assembly  300  which may optionally comprise a shape-lockable elongate body  302  with off-axis visualization assembly  256 , as above. In this variation, first and second tool arms  304 ,  306 , respectively, may comprise arm members each having a first and second preset bending portion  308 ,  310 , respectively, each configured to bend at a preset angle once free from the constraints of the tool lumens, as shown in  FIG. 27B . Once unconstrained, tools arms  304 ,  306  may be rotated about its longitudinal axis, as shown in  FIG. 27C , to accomplish any number of procedures on the tissue while visualized via off-axis endoscope  258 . Tool arms  304 ,  306  may be fabricated from shape memory alloys, such as a Nickel-Titanium alloy, or from spring stainless steels, or any other suitable material which may allow for the tools arms  304 ,  306  to reconfigure itself from a first low-profile configuration to an off-axis deployment configuration. 
       FIG. 27D  shows a perspective view of yet another variation in which elongate body  302  may have first and second articulatable tool arms  312 ,  314  which are freely rotatable about their respective longitudinal axes. Visualization assembly  256  may comprise any of the variations described above, particularly the variation as described for  FIGS. 24A and 24B . 
       FIG. 28  shows a perspective view of another variation of end effector assembly  320  in which optionally shape-lockable elongate body  322  may comprise a separate visualization lumen  324  having a lumen opening  326  through which a guidewire  328  having a preset configuration may be advanced. Visualization lumen  324  may be integrated with elongate body  322  or separately attached to an outer surface of elongate body  322 . Guidewire  328  may be comprised of a shape memory alloy, as above, and carry an imaging chip  330 , e.g., a CCD imager, on a distal end of the guidewire  328 . Guidewire  328  may be preset to reconfigure itself into an off-axis configuration to provide the off-axis visualization distally of elongate body  322 , as shown. Furthermore, imaging chip  330  may be connected via wires through guidewire  328  to a monitor at a location proximal to elongate body  322  or imaging chip  330  may be adapted to wirelessly transmit images to a receiving unit external to a patient body. Moreover, guidewire  328  may also be advanced through a working lumen of elongate body  322  if so desired. 
     In another alternative, end effector assembly  340  shown in  FIG. 29  may comprise an optionally shape-lockable body  342  having visualization member  344  pivotably mounted near or at a distal end of body  342  via pivot  348 . Visualization member  344  may have an imager  346 , e.g., an imaging chip such as a CCD chip, positioned upon a distal end of member  344 , which may be configured to articulate about pivot  348  such that imager  346  is provided an off-axis view of the region distal of elongate body  342 . 
     In another variation, the off-axis visualization may be provided, e.g., within the stomach S, via one or more capsules  350  having integrated imagers  352  positioned within one or more regions of the stomach S. Rather than, or in combination with, off-axis visualization lumen or platform  18 , a number of imaging capsules  350  may be temporarily adhered to the interior stomach wall, e.g., via clips  354  attached to the capsule body. The imaging portions  352  of the capsules  350  may be positioned against the stomach wall such that one or more capsules  350  are pointed towards a tissue region of interest. The endoluminal assembly  10  may then be articulated towards the tissue region of interest with either off-axis visualization platform  18  or one or more capsules  350  providing a number of off-axis views for any number of procedures to be accomplished. Imaging capsules such as the PillCam™ are generally used for capsule endoscopy and may be commercially obtained from companies like Given Imaging Ltd. (Israel). 
     Turning now to  FIGS. 31A and 31B , imaging assembly or endoscope  370  may be advanced through visualization lumen  364 , which runs through optionally rigidizable elongate body  360 , and passed through opening or skive  362  defined along the outer surface near the distal end of elongate body  360 . Imaging assembly  370  may be alternatively passed distally through visualization lumen  364  to the opening defined through the atraumatic distal end  368 . When positioned through skive  362 , imaging assembly  370  may be articulated into an off-axis configuration relative to the longitudinal axis of elongate body  360  such that the imaging element at its distal end is directed to the area distal to the elongate body  360  along its longitudinal axis, as described above. Such a general configuration may allow for the viewing of various instruments passed through any of the instrument lumens  366  defined through elongate body  360 . 
     In this example, imaging assembly  370  may have an articulatable imaging element  372  positioned at its distal end, which may be rotated in any number of directions.  FIG. 31B  shows a cross-sectional illustration of the articulatable imaging element  372  partially removed from imaging assembly  370 . Imaging element  372  may generally have a rotatable housing  374  containing the imager  376 , e.g., CCD or CMOS chip, connected via at least one electrical wire  380  routed through an imaging assembly lumen  384  defined through assembly  370  to a proximal end of the device. The electrical wire  380  may be connected to a processor to allow viewing of images from outside the patient body. The rotatable housing  374  may be rotated in any number of directions, as indicated by the arrows, by alternately tensioning any number of control wires  378  which may be routed through control wire lumens  382  defined through imaging assembly  370 . The distal end of imaging assembly  370  may be configured to rotatingly receive and hold rotatable housing  374  in a secure manner while the housing  374  is articulated. 
     Although imaging assembly  370  may be articulated to direct its distal end to a desired tissue region for optimal imaging, the addition of an optional rotatable imaging element  372  may further facilitate the imaging of various tissue regions without having to reposition the entire assembly. 
     In yet another variation for off-axis imaging,  FIGS. 32A to 32C  show an instrument where the optionally rigidizable elongate body  360  may use a pull-wire  390  to control the off-axis articulation of the imaging assembly. As shown in  FIG. 32A , pull-wire  390  may be routed through skive  362  and through a pull-wire opening  392  located distal of skive  362 . Pull-wire  390  may be routed through pull-wire opening  392  proximally through the length of elongate body  360  where the pull-wire  390  may be controlled. The distal end of pull-wire  390  may be attached to a distal end of the imaging assembly  394  at attachment point  398  and as imaging assembly or endoscope  394  is advanced through skive  362 , as shown in  FIG. 32B , the pull-wire  390  may be tensioned from its proximal end outside the patient body. As shown in  FIG. 32C , urging or pulling pull-wire  390  may redirect or bend a distal portion  400  of the imaging assembly  394  with the imager  396  such that the imager  396  is pointed to the region distal to the elongate body  360 . 
     Another variation is illustrated in  FIG. 33A  which shows elongate body  360  having a swing arm or member  410  rotatably connected via pivot  412  to the elongate body  360  at a location distal to skive  362 . A distal end of swing arm  410  may be attached to endoscope  394  via an attachment mechanism  414 , e.g., collar, pinned connection, adhesive, etc., such that when endoscope  394  is urged distally through elongate body  360  and out of skive  362 , the distal end of endoscope  394  is constrained to follow an arc by the swing arm  410  as the distal end of endoscope  394  pivots about pivot  412 , as shown in  FIG. 33B . The length of swing arm  410  may be varied depending upon the desired height and positioning of imager  396  in its off-axis configuration. 
     Moreover, swing arm  410  may be configured as a simple length or it may be configured into any number of structures provided that it is able to pivot relative to elongate body  360  and position imager  396  into its off-axis position. Additionally, a mechanical stop may be positioned adjacent to pivot  412  to prevent over-arcing of swing arm  410 ; alternatively, the imaging assembly or endoscope  394  may be limited from being advanced distally out of skive  362  beyond a pre-determined point to prevent over-arcing of the imager  396 . 
     In yet another variation, a balloon  420  which is flexible in its deflated state may be positioned in close contact against a distal portion of the imaging assembly or endoscope  394 . Balloon  420  may be in fluid communication through inflation lumen  422  through a length of elongate body  360  to an inflation pump  424  located outside the patient body, as shown in  FIG. 34A . The balloon  420  may be configured such that when inflated with a fluid or gas, the inflated balloon  420  conforms to a bent configuration which may be predetermined. The balloon  420  may, for instance, be inflated only along a single side such that filling the balloon  420  results in an asymmetric shape. When the endoscope  394  with balloon  420  is advanced out of skive  362 , the balloon  420  may be inflated via a fluid (such as saline, water, etc.) or gas (such as air, nitrogen, carbon dioxide, etc.) such that the balloon  420  conforms to its bent configuration and also urges the wrapped endoscope  394  to conform into a bent or curved off-axis configuration, as shown in  FIG. 34B . 
     Alternatively, rather than utilizing an inflation balloon  420 , a scaffold or tubular covering having a scaffold  420 ′ embedded therein which is made from a super-elastic or shape-memory material may be conformed or wrapped around the distal portion of endoscope  394 . Such a scaffold may be made from a super-elastic or shape-memory alloy such as Nitinol. If a super-elastic scaffold is used, the endoscope  394  may be automatically urged into a bent or curved configuration when advanced out of skive  362 . Alternatively, a shape-memory alloy scaffold may be electrically connected via one or more wires  422 ′ to a power supply  424 ′, which may be activated to actuate the scaffold  420 ′ into a bent or curved configuration. 
     Yet another variation is shown in  FIG. 35A  in which endoscope  394  may be wrapped or at least partially surrounded by a sleeve  430  having a pre-formed bent or curved configuration. Sleeve  430  may be composed of a super-elastic or shape-memory material scaffold or covering, as described above, which is biased to form the bent or curved configuration when unconstrained. To maintain a straightened configuration when advanced through elongate body  360  and out of skive  362 , a straightening wire or mandrel  432 , made for example from stainless steel, Nitinol, a polymeric material, etc., may be disposed within sleeve  430 . When sleeve  430  has been desirably positioned through skive  362 , wire or mandrel  432  may be pulled or tensioned from its proximal end until it is withdrawn from sleeve  430 , thereby allowing sleeve  430  to reconfigure itself into its relaxed configuration and to redirect imager  396  into its off-axis configuration, as shown in  FIG. 35B . To withdraw sleeve  430  and endoscope  394  from the patient body, endoscope  394  may be simply pulled proximally through skive  362  while straightening sleeve  430  and back into elongate body  360 . 
     Another variation may utilize a sleeve  440  made from an electro-active polymer (EAP) material such as polymer-metal composites, conductive polymers, ferro-electric polymers, etc., as shown in  FIG. 36A . EAP sleeve  440  may be wrapped completely or at least partially about endoscope  394  such that sleeve  440  remains flexibly compliant when passed through elongate body  360  and skive  362 . EAP sleeve  440  may be electrically connected via electrical connection  442  to a power supply  444  located external to the patient body such that when power supply  444  is activated, EAP sleeve  440  may be stimulated to reconfigure itself into a bent or curved off-axis configuration, as seen in  FIG. 36B , such that imager  396  is directed distal to the elongate body  360 . Shutting power supply  444  off may allow EAP sleeve  440  to lose its curved configuration and transition back into its flexible state for withdrawal through skive  362  and from the patient body. 
     Another variation for off-axis visualization may utilize multiple, e.g., two or more, off-axis visualization elements. Illustrated in the side view of  FIG. 37A , two or more imaging assemblies  450  which are reconfigurable between a straightened and curved configuration may be each advanced through a corresponding lumen  366  defined through elongate body  360 . Each imaging assembly  450  may be configured such that an imaging element  454 , such as an optical fiber, CCD or CMOS chip, etc., may be mounted near or at the distal end of a curved or bendable section  452  such that when the curved section  452  is advanced from elongate body  360 , the imaging element  454  is directed into an off-axis position relative to the longitudinal axis defined by the elongate body  360 . 
     In one example, two imaging assemblies  450  may be advanced through their respective adjacent lumens  366  and rotated within their lumens  366  to align the respective imagers  454  to a common tissue region. In another example, four imaging assemblies  450  may be advanced through respective lumens  366 , as shown in the end view of  FIG. 37B , and advanced out of elongate body  360  such that each imaging assembly  450  is radially configured in an off-axis position with respect to the longitudinal axis of elongate body  360 . Moreover, each imaging assembly  450  may be uniformly or arbitrarily positioned with respect to one another in its deployed configuration. 
     In a similar variation, one or more imaging assemblies  450  may be advanced through one or more lumens  366  while contained within a tubular retaining sleeve  456  which is retractable with respect to the imaging assembly  450 , as shown in  FIG. 38A . Retaining sleeve  456  may be advanced through lumen  366  from atraumatic distal end  368  prior to or simultaneously with imaging assemblies  450  and retaining sleeve  456  may be retracted relative to imaging assemblies  450  leaving the one or more assemblies  450  to reconfigure into its curved configuration, as shown in  FIG. 38B . 
     Another variation utilizing an inflatable balloon assembly  460  which defines one or more curved lumens therethrough may be utilized. As shown in  FIG. 39A , an un-inflated balloon assembly  460  may lie in its collapsed shape in a low profile against elongate body  360 . When the interior  472  of balloon  462  is inflated or expanded with a gas (such as nitrogen, carbon dioxide, air, etc.) or liquid (such as saline, water, etc.), balloon  462  which may be made from a distensible or expandable material may expand, as shown in  FIG. 39B . In its expanded configuration, balloon  462  may define or more unobstructed lumens  466  extending through the balloon  462  from a working lumen opening  470  in elongate body  360  and terminating in a corresponding lumen opening  464  defined along a side or at the terminal end of the balloon  462 , as shown in  FIG. 39C . 
     Lumens  466  may curve radially outward within balloon  462  with respect to the longitudinal axis of elongate body  360  and then curve radially back inwards  468  with respect to the longitudinal axis. This curvature may be such that any tools or endoscopic instruments passed through lumen  466  are directed towards the longitudinal axis of elongate body  360  and to a tissue region of interest for any number of procedures to be performed. 
     In many endoscopic procedures, visualization of a tissue region of interest often requires repositioning of the imaging assembly or endoscope and re-visualizing the tissue region. Repositioning typically involves pulling or directing the endoscope away from the tissue region and then re-visualizing the tissue region from another position or from a more proximal location. One example for endoscopically simulating the repositioning and re-visualizing of a tissue region may be seen in  FIGS. 40A and 40B . As illustrated in  FIG. 40A , endoscope or imaging assembly  480  may be advanced through elongate body  360  and out of lumen  364 , where imager  484  may be articulated into a first off-axis position relative to a longitudinal axis of elongate body  360 , as described previously. In its first off-axis configuration, a target area distal to elongate body  360  may be visualized within a first field-of-view  486 . 
     If a larger visual perspective is desired, an articulatable section  482  of endoscope  480  may be further urged or articulated from its proximal end outside the patient body into a second off-axis configuration, as shown in  FIG. 40B , which is more proximal than the first off-axis configuration. The resulting expanded field-of-view  486 ′ may thus provide for a larger visual perspective of the target area being visualized without having to reposition a length or the entire length of elongate body  360  relative to the visualized target area. 
     In another alternative, endoscope or imaging assembly  480  may be positioned into its first off-axis configuration, as above, to provide a first field-of-view  486 , as shown in  FIG. 41A . Endoscope  480  may then be withdrawn at least partially through elongate body  360  and then re-advanced through a skive  362  into a second off-axis configuration such that imager  484  is repositioned proximal of the first off-axis configuration to provide an expanded field-of-view  486 ′, as shown in  FIG. 41B . Skive  362 , as described herein and also in U.S. patent application Ser. No. 10/797,485 filed Mar. 9, 2004 (U.S. Pat. Pub. No. 2004/0249367A1), which is incorporated herein by reference in its entirety, may be defined at any number of locations along the length of elongate body  360  proximal to the distal tip  368 . 
     Aside from physically repositioning the endoscope or imaging assembly  480 , another variation may incorporate an imaging system having a variable field-of-view which may be altered by repositioning the optics within the imager  484 . One such example of an alterable field-of-view is shown and described in U.S. Pat. Pub. No. 2005/0267335 A1 filed May 18, 2005 to Okada et al., which is incorporated herein by reference in its entirety. Such a device may be optionally incorporated into any of the imaging assemblies described herein as practicable. 
     In another variation for utilizing one or more skives along the length of elongate body  490 ,  FIG. 42  illustrates an example in which multiple skives may be defined along the body. In this example, endoscope  394  may be positioned into its off-axis configuration through a distally positioned skive  362  to provide a first field-of-view. An additional second skive  492  and a third skive  494  may be positioned proximally along the length  490  such that the endoscope  394  may be positioned in alternate proximal off-axis positions  394 ′,  394 ″ to provide alternate views of the target area being visualized. More than three skives may be utilized along the elongate body  490 , as practicable, and the skives may be varied relative to its circumferential position, as desired. For instance, one or more skives may be aligned linearly along the length of elongate body  490  such that the skives are located along the same side of elongate body  490 . 
     Alternatively, the one or more skives may be aligned in alternating or non-uniform patterns. Furthermore, if the one or more skives are located along different sides of the elongate body  490 , multiple visualization instruments (or multiple other endoscopic instruments) may be passed simultaneously through elongate body  490  to exit each skive, if so desired. 
     Aside from articulating visualization assemblies into off-axis configurations, off-axis imaging relative to the elongate body may be provided alternatively by utilizing various in-line angled configurations. One example is shown in  FIG. 43A  which illustrates elongate body  360  with a visualization element positioned near or at the distal end of elongate body  360  to provide an angled field-of-view  500  relative to the longitudinal axis of elongate body  360 .  FIG. 43B  shows a partial cross-sectional view of elongate body  360 , which illustrates an imaging assembly  504 , e.g., optical fiber bundles, having a rotatable prism assembly  502  positioned distal of the imaging assembly  504 . To alter the angle of the imaging field-of-view  500 , prism  502  may be rotated relative to the imaging assembly  504  via pull-wires, motors, or any other number of mechanisms. In other variations, an imaging chip, such as a CCD or CMOS chip, may be utilized to rotate in an angled configuration to provide the off-axis imaging. 
     Another example for in-line off-axis imaging is provided in  FIG. 44A , which shows a partial side view of elongate body  360  having an imaging assembly  510 , such as optical fibers or imaging chips, rotatably positioned relative to elongate body  360 . An off-axis imaging chip  512  may be positioned near or at the distal end of imaging assembly  510 . Mounted, removably or permanently, upon the distal end of elongate body  360  are one or more reflectors  514  which extend distally from and which are pivotally attached to elongate body  360 . Off-axis imaging chip  512  may be selectively rotated to view a tissue region by viewing images reflected from the one or more reflectors  514 . The reflectors  514  may be made from a number of highly reflective materials, such as polished stainless steels or other metals, reflective glass, etc. 
     During endoluminal advancement through the patient body, the one or more reflectors  514  may be retracted into a low profile and then pivoted radially into an angled position to provide for imaging. Moreover, the radial expansion of the reflectors  514  may also provide for tissue retraction of any obstructing tissue structures adjacent or proximate to the tissue region being visualized.  FIG. 44B  shows an end view of the radially expanded reflectors  514 . To prevent pinching of tissue between the expanded reflectors  514 , an expandable covering  516  made from a distensible material, such as silicone, polyurethane, etc., may be optionally provided between the reflectors  514  or around the entire imaging assembly. 
     In addition to providing for the off-axis visualization, whether in-line or off-axis relative to the longitudinal axis of the elongate body, additional visualization enhancements may be optionally provided in any of the variations described herein. One example of such a visualization enhancement is shown in  FIG. 45A , which illustrates an end view of elongate body  360  with an imaging assembly  520  translatably positioned within lumen  364 . Imaging assembly  520  may provide multiple adjacent imaging chips  522 , e.g., CCD or CMOS chips, positioned at the distal end of assembly  520 . 
       FIGS. 45B to 45D  show a detail view of the imaging chips  522  and illustrate an example for their use. In this example, first chip  524 , second chip  526 , and third chip  528  may be uniformly and linearly aligned relative to one another. To provide the visualization, first chip  524  may be activated at a time t=t 0  to provide a first field-of-view  524 ′, as shown in  FIG. 45B . The image provided in the first-field of view  524 ′ may be captured and stored via a computer (not shown). Second chip  526  may be activated subsequently at a time t=t 0 +dt 1  to provide a second field-of-view  526 ′ upon first chip  524  being de-activated, as shown in  FIG. 45C . The image provided in the second field-of-view  526 ′ may comprise an image of the region visualized which is slightly adjacent to the image captured in the first field-of-view  524 ′. Second field-of-view  526 ′ may likewise be captured and stored via the computer. Third chip  528  may then be activated subsequently at a time t=t 0 +dt 2  to provide a third field-of-view  528 ′ upon second chip  526  being de-activated, as shown in  FIG. 45D . The image provided by the third field-of-view  528 ′ may likewise comprise an image of the region which is slightly adjacent to the image captured in the second field-of-view  526 ′. Third field-of-view  528 ′ may also be captured and stored in the computer. 
     Once all three images have been sequentially captured, the stored images may be processed via the computer or processor to result in a simulated singular panoramic composite image  530  of the tissue region, as shown in  FIG. 45E . The sequential imaging, capturing, and displaying may be continuously performed during a procedure to provide enhanced imaging to the practitioner. 
     Another example for providing enhanced imaging in any of the variations described herein is shown in  FIG. 46 . In this example, imaging provided by any of the endoluminal instruments described herein may be combined into a fluoroscopic-endoscopic imaging system  540  where images provided by a fluoroscope  542 , which is typically used to provide fluoroscopic images via extra-corporeal imaging, may be combined with images provided by any of the endoluminal instruments  544  described herein (or even with conventional endoscopes), which provide images obtained via endoluminal intra-corporeal imaging. 
     A patient may be positioned upon a platform  546  for fluoroscopic imaging. The fluoroscopic images may be transmitted via electrical connection  550  to a processor  552 . The endoluminal instrument  544  may be likewise connected via electrical connection  548  to processor  552  to provide endoluminal images. Processor  552  may be configured to process both the fluoroscopic and endoluminal images or separate processors may be utilized to individually process each respective images which may then be combined via a third processor (not shown) in communication with each separate processor. 
     In either case, the fluoroscopic and endoluminal images may then be transmitted and displayed via electrical connection  560  on a monitor  558  and/or optionally via electrical connection  564  through goggles or glasses  562 , which may be worn by the practitioner during the procedure. A switch  554  (e.g., toggle, foot switch, etc.) connected to processor  552  via electrical connection  556  may be actuated by the practitioner, nurse, or technician to selectively switch the image displayed on the monitor  558  and/or goggles  562  between the fluoroscopic image and the endoluminal image. Alternatively, the fluoroscopic image and/or the endoluminal image may be displayed simultaneously on the monitor  558  and/or goggles  562  in a split-screen or picture-in-picture manner to allow the practitioner to view both the fluoroscopic and endoluminal images simultaneously without having to toggle between the two. Such a system  540  may facilitate efficient visualization and may also reduce the amount of equipment in the operating room and/or endoscopy suite during a procedure. 
     Although various illustrative embodiments are described above, it will be evident to one skilled in the art that a variety of combinations of aspects of different variations, changes, and modifications are within the scope of 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.