Patent Publication Number: US-2022218182-A1

Title: Methods and apparatus for inverting a hollow sleeve and thereafter reverting an inverted hollow sleeve

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATION 
     This patent application claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 63/114,070, filed Nov. 16, 2020 by Lumendi Ltd. and David Gaddy et al. for METHODS AND APPARATUS FOR INVERTING A HOLLOW SLEEVE AND THEREAFTER REVERTING AN INVERTED HOLLOW SLEEVE (Attorney&#39;s Docket No. LUMENDI-40), which patent application is hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to methods and apparatus in general, and more particularly to methods and apparatus for inverting a hollow sleeve and thereafter reverting an inverted hollow sleeve, and to a hollow sleeve having a hydrophilic coating applied to the interior surface of the hollow sleeve. 
     BACKGROUND OF THE INVENTION 
     The human body comprises many different body lumens and body cavities. By way of example but not limitation, the human body comprises body lumens such as the gastrointestinal (GI) tract, blood vessels, lymphatic vessels, the urinary tract, fallopian tubes, bronchi, bile ducts, etc. By way of further example but not limitation, the human body comprises body cavities such as the head, chest, abdomen, nasal sinuses, bladder, cavities within organs, etc. 
     In many cases it may be desirable to endoscopically examine and/or treat a disease process or abnormality which is located within, or on the side wall of, a body lumen and/or body cavity. By way of example but not limitation, it may be desirable to examine the side wall of the gastrointestinal tract for lesions and, if a lesion is found, to biopsy, remove and/or otherwise treat the lesion. 
     The endoscopic examination and/or treatment of the side wall of a body lumen and/or body cavity can be complicated by the anatomic configuration (both regional and local) of the side wall of the body lumen and/or body cavity, and/or by the consistency of the tissue making up the side wall of the body lumen and/or body cavity, and/or by the tethering of the side wall of the body lumen and/or body cavity to other anatomical structures. 
     By way of example but not limitation, the intestine is an elongated tubular organ having an inner lumen and is characterized by frequent turns (i.e., the regional anatomic configuration of the intestine) and a side wall characterized by numerous folds (i.e., the local anatomic configuration of the intestine), with the side wall tissue having a relatively soft, pliable consistency, and with the colon in particular being tethered to the abdomen and/or other abdominal structures via soft tissue. It can be difficult to fully visualize the side wall of the intestine, and/or to treat a lesion formed on the side wall of the intestine, due to this varying side wall anatomic configuration (both regional and local), its relatively soft, pliable consistency, and its tethering to other anatomical structures via soft tissue. By way of example but not limitation, in the case of colonoscopies, it has been found that approximately 5-40% of patients have an anatomic configuration (regional and/or local) of the side wall, and/or a tissue consistency, and/or colon tethering to other anatomical structures, which makes it difficult to fully visualize the anatomy (including pathologic conditions of that anatomy, such as polyps or tumors) using conventional endoscopes, and/or to fully access the anatomy using instruments introduced through conventional endoscopes. 
     In addition to the foregoing, it has also been found that some body lumens and/or body cavities can spasm and/or contract spontaneously but especially when an endoscope or other instrument is inserted into the body lumen and/or body cavity. This spasming and/or contraction can cause the body lumen and/or body cavity to constrict and/or otherwise move and/or change its configuration, which can further complicate and/or compromise endoscopic visualization of the anatomy, and/or further complicate and/or compromise access to the anatomy using instruments introduced through conventional, flexible endoscopes. In addition, during examination of the colon, which is typically conducted while both inserting and withdrawing the endoscope through the colon, the endoscope may grip and/or otherwise gather the colon during insertion and withdrawal and then suddenly slip and release the colon. This results in the endoscope moving quickly past significant lengths of the colon, thereby making accurate examination of the colon challenging. 
     It would, therefore, be highly advantageous to provide novel apparatus capable of manipulating the side wall of a body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure. 
     It would also be highly advantageous to provide novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (e.g., endoscopes, articulating and/or non-articulating devices such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) inserted into a body lumen and/or body cavity with respect to the side wall of the body lumen and/or body cavity, whereby to facilitate the precision use of those instruments. 
     Among other things, it would be highly advantageous to provide novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of endoscopes (and hence also steadying and/or stabilizing the distal tips and/or working ends of other instruments inserted through the working channels of those endoscopes, such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.). 
     And it would be highly advantageous to provide novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) advanced to the surgical site by means other than through the working channels of endoscopes. 
     It would also be highly advantageous to be able to straighten bends, “iron out” inner luminal surface folds and create a substantially static or stable side wall of the body lumen and/or body cavity, whereby to enable more precise visual examination (including visualization of areas initially hidden or outside the field of view) and/or therapeutic intervention. 
     SUMMARY OF THE INVENTION 
     The present invention comprises the provision and use of novel apparatus for manipulating the side wall of a body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure. 
     The present invention also comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (e.g., endoscopes, articulating and/or non-articulating devices such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) inserted into a body lumen and/or body cavity with respect to the side wall of the body lumen and/or body cavity, whereby to facilitate the precision use of those instruments. 
     Among other things, the present invention comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of endoscopes (and hence also steadying and/or stabilizing the distal tips and/or working ends of other instruments inserted through the working channels of those endoscopes, such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.). 
     And the present invention comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) advanced to the surgical site by means other than through the working channels of endoscopes. 
     And the present invention comprises the provision and use of novel apparatus capable of straightening bends, “ironing out” folds and creating a substantially static or stable side wall of the body lumen and/or body cavity which enables more precise visual examination (including visualization of areas initially hidden or outside the field of view) and/or therapeutic intervention. 
     In one preferred form of the present invention, there is provided apparatus comprising: 
     a sleeve adapted to be slid over the exterior of an endoscope; 
     a proximal balloon secured to said sleeve; 
     an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon; 
     a push tube slidably mounted to said sleeve; and 
     a distal balloon secured to the distal end of said push tube, the interior of said distal balloon being in fluid communication with said push tube, wherein said distal balloon is capable of assuming a deflated condition and an inflated condition, and further wherein when said distal balloon is in its deflated condition, an axial opening extends therethrough, said axial opening being sized to receive the endoscope therein, and when said distal balloon is in its inflated condition, said axial opening is closed down. 
     In another preferred form of the present invention, there is provided a method for performing a procedure in a body lumen and/or body cavity, said method comprising: 
     providing apparatus comprising:
         a sleeve adapted to be slid over the exterior of an endoscope;   a proximal balloon secured to said sleeve;   an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon;   a push tube slidably mounted to said sleeve; and   a distal balloon secured to the distal end of said push tube, the interior of said distal balloon being in fluid communication with said push tube, wherein said distal balloon is capable of assuming a deflated condition and an inflated condition, and further wherein when said distal balloon is in its deflated condition, an axial opening extends therethrough, said axial opening being sized to receive the endoscope therein, and when said distal balloon is in its inflated condition, said axial opening is closed down;       

     positioning said apparatus in the body lumen and/or body cavity; 
     inflating said proximal balloon; 
     advancing said push tube distally; 
     inflating said distal balloon; and 
     performing the procedure. 
     In another preferred form of the present invention, there is provided apparatus comprising: 
     a sleeve adapted to be slid over the exterior of an endoscope, said sleeve comprising a passageway formed integral with said sleeve and a lumen formed integral with said sleeve for receiving an instrument; 
     a proximal balloon secured to said sleeve; 
     an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon; 
     a push tube slidably mounted in said passageway of said sleeve; and 
     a distal balloon secured to the distal end of said push tube, the interior of said distal balloon being in fluid communication with said push tube. 
     In another preferred form of the present invention, there is provided a method for performing a procedure in a body lumen and/or body cavity, said method comprising: 
     providing apparatus comprising:
         a sleeve adapted to be slid over the exterior of an endoscope, said sleeve comprising a passageway formed integral with said sleeve and a lumen formed integral with said sleeve for receiving an instrument;   a proximal balloon secured to said sleeve;   an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon;   a push tube slidably mounted in said passageway of said sleeve; and   a distal balloon secured to the distal end of said push tube, the interior of said distal balloon being in fluid communication with said push tube;       

     positioning said apparatus in the body lumen and/or body cavity; 
     inflating said proximal balloon; 
     advancing said push tube distally; 
     inflating said distal balloon; and 
     performing the procedure. 
     In another preferred form of the present invention, there is provided apparatus comprising: 
     a sleeve adapted to be slid over the exterior of an endoscope so as to substantially cover the endoscope from a point adjacent to the distal end of the endoscope to a point adjacent to the handle of the endoscope; 
     a proximal balloon secured to said sleeve; 
     an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon; 
     a push tube slidably mounted to said sleeve; and 
     a distal balloon secured to the distal end of said push tube, the interior of said distal balloon being in fluid communication with said push tube. 
     In another preferred form of the present invention, there is provided a method for performing a procedure in a body lumen and/or body cavity, said method comprising: 
     providing apparatus comprising:
         a sleeve adapted to be slid over the exterior of an endoscope so as to substantially cover the endoscope from a point adjacent to the distal end of the endoscope to a point adjacent to the handle of the endoscope;   a proximal balloon secured to said sleeve;   an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon;   a push tube slidably mounted to said sleeve; and   a distal balloon secured to the distal end of said push tube, the interior of said distal balloon being in fluid communication with said push tube;       

     positioning said apparatus in the body lumen and/or body cavity; 
     inflating said proximal balloon; 
     advancing said push tube distally; 
     inflating said distal balloon; and 
     performing the procedure. 
     In another preferred form of the present invention, there is provided apparatus comprising: 
     a sleeve adapted to be slid over the exterior of an endoscope; 
     a proximal balloon secured to said sleeve; 
     an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon; 
     a pair of push tubes slidably mounted to said sleeve; and 
     a distal balloon secured to the distal ends of said pair of push tubes, the interior of said distal balloon being in fluid communication with said pair of push tubes. 
     In another preferred form of the present invention, there is provided a method for performing a procedure in a body lumen and/or body cavity, said method comprising: 
     providing apparatus comprising:
         a sleeve adapted to be slid over the exterior of an endoscope;   a proximal balloon secured to said sleeve;   an inflation/deflation tube carried by said sleeve and in fluid communication with the interior of said proximal balloon;   a pair of push tubes slidably mounted to said sleeve; and   a distal balloon secured to the distal ends of said pair of push tubes, the interior of said distal balloon being in fluid communication with said pair of push tubes;       

     positioning said apparatus in the body lumen and/or body cavity; 
     inflating said proximal balloon; 
     advancing said pair of push tubes distally; 
     inflating said distal balloon; and 
     performing the procedure. 
     In yet another preferred form of the invention, there is provided apparatus for inverting an elongated flexible tubular sleeve having a proximal end, a distal end and a central lumen extending between the proximal end and the distal end, the apparatus comprising: 
     a hollow tube comprising a proximal end, a distal end and a central lumen extending between the proximal end and the distal end; and 
     an elongated rod movably disposed within the central lumen of the hollow tube, the elongated rod having a proximal end and a distal end, wherein the distal end of the elongated rod comprises a sleeve plug for securing a distal end of an elongated flexible tubular sleeve to the distal end of the hollow tube; 
     wherein, when the elongated flexible tubular sleeve is disposed over the hollow tube, (i) the sleeve plug of the elongated rod is configured to be moved proximally to clamp the distal end of the elongated flexible tubular sleeve to the distal end of the hollow tube, and (ii) the sleeve plug of the elongated rod is configured to be moved distally to release the distal end of the elongated flexible tubular sleeve from the distal end of the hollow tube; 
     and further wherein when the distal end of the elongated flexible tubular sleeve is clamped to the distal end of the hollow tube, the proximal end of the elongated flexible tubular sleeve can be pulled toward the distal end of the hollow tube to invert the elongated flexible tubular sleeve. 
     In yet another preferred form of the invention, there is provided a method for inverting an elongated, flexible tubular sleeve having a proximal end, a distal end and a central lumen extending between the proximal end and the distal end, the method comprising: 
     providing an apparatus comprising:
         a hollow tube comprising a proximal end, a distal end and a central lumen extending between the proximal end and the distal end; and   an elongated rod movably disposed within the central lumen of the hollow tube, the elongated rod having a proximal end and a distal end, wherein the distal end of the elongated rod comprises a sleeve plug for securing a distal end of an elongated flexible tubular sleeve to the distal end of the hollow tube;       

     disposing the elongated flexible tubular sleeve over the hollow tube; 
     moving the elongated rod proximally, whereby to clamp the distal end of the elongated flexible tubular sleeve to the distal end of the hollow tube; and 
     pulling the proximal end of the elongated flexible tubular sleeve distally toward the distal end of the elongated flexible tubular sleeve, whereby to invert the elongated flexible tubular sleeve. 
     In yet another preferred form of the invention, there is provided apparatus comprising: 
     a sleeve adapted to be slid over the exterior of an endoscope, wherein the sleeve comprises a sleeve proximal end, a sleeve distal end and a sleeve lumen extending therebetween, and further wherein the sleeve is configured to be slid over the exterior surface of the endoscope so as that the interior surface of the sleeve lumen substantially covers the exterior surface of the endoscope from a point adjacent to the distal end of the endoscope to a point adjacent to the handle of the endoscope, wherein the interior surface of the sleeve lumen comprises a hydrophilic coating; and 
     at least one support channel carried by the sleeve, wherein the at least one support channel comprises a channel proximal end, a channel distal end and a channel lumen extending therebetween. 
     In yet another preferred form of the invention, there is provided a method for applying a hydrophilic coating to a sleeve adapted to be slid over the exterior of an endoscope, wherein the sleeve comprises:
         a sleeve proximal end, a sleeve distal end and a sleeve lumen extending therebetween, and further wherein the sleeve is configured to be slid over the exterior of the endoscope so as that the interior surface of the sleeve lumen substantially covers the exterior of the endoscope from a point adjacent to the distal end of the endoscope to a point adjacent to the handle of the endoscope; and at least one support channel carried by the sleeve, wherein the at least one support channel comprises a channel proximal end, a channel distal end and a channel lumen extending therebetween;       

     wherein the method comprises:
         inverting the sleeve;       

     applying the hydrophilic coating to the inverted interior surface of the sleeve lumen; 
     allowing the hydrophilic coating to cure; and 
     reverting the sleeve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
         FIG. 1  is a schematic view showing novel apparatus formed in accordance with the present invention, wherein the novel apparatus comprises, among other things, a sleeve for disposition over the end of an endoscope, an aft balloon mounted to the sleeve, a pair of push tubes slidably mounted to the sleeve, a fore balloon mounted to the distal end of the push tubes, and a push tube handle mounted to the proximal ends of the push tubes; 
         FIGS. 2-4  are schematic views showing various dispositions of the fore balloon relative to the aft balloon; 
         FIG. 5  is a schematic view showing further details of the distal end of the apparatus shown in  FIG. 1 ; 
         FIG. 6  is a section view taken along line  6 - 6  of  FIG. 5 ; 
         FIGS. 7 and 8  are schematic views showing further details of the fore balloon; 
         FIG. 8A  is a schematic view showing the push tube handle; 
         FIGS. 9 and 10  are schematic views showing construction details of the fore balloon; 
         FIG. 11  is a schematic view showing one form of inflation mechanism provided in accordance with the present invention; 
         FIG. 11A  is a schematic view showing another form of inflation mechanism provided in accordance with the present invention; 
         FIGS. 12 and 13  are schematic views showing another form of inflation mechanism provided in accordance with the present invention; 
         FIG. 14  is a schematic view showing relief valves which may be used to ensure that the pressure within the fore balloon and/or aft balloon does not exceed a predetermined level; 
         FIG. 15  is a schematic view showing a retraction system which may be used to take up slack in a flexible tube of the apparatus shown in  FIG. 1 ; 
         FIGS. 16-30  are schematic views showing preferred ways of using the apparatus of  FIG. 1 ; 
         FIG. 30A  is a schematic view showing an alternative construction for the push tubes and push tube handle of the present invention; 
         FIG. 31  is a schematic view showing another form of the sleeve, wherein the sleeve comprises additional lumens for receiving instruments; 
         FIGS. 32-35  are schematic views showing how instruments may be advanced through the additional lumens of the sleeve; 
         FIG. 36  is a schematic view showing instrument guide tubes which may be disposed in the additional lumens of the sleeve, wherein instruments may be advanced through the instrument guide tubes; 
         FIGS. 37-41A  are schematic views showing a novel system for inverting a sleeve; 
         FIGS. 42-50, 50A and 51-66  are schematic views showing a novel method for inverting a sleeve; 
         FIGS. 67-70  are schematic views showing a novel system for reverting an inverted sleeve; 
         FIGS. 71-82  are schematic views showing a novel method for reverting an inverted sleeve; and 
         FIGS. 83-96  are schematic views showing an alternative clamp for mounting a distal end of a sleeve to a hollow tube and a method for using the alternative clamp to invert the sleeve. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention comprises the provision and use of novel apparatus for manipulating the side wall of a body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure. 
     (As used herein, the term “endoscopic procedure” is intended to mean substantially any minimally-invasive or limited access procedure, diagnostic and/or therapeutic and/or surgical, for accessing, endoluminally or transluminally or otherwise, the interior of a body lumen and/or body cavity for the purposes of viewing, biopsying and/or treating tissue, including removing a lesion and/or resecting tissue, etc.) 
     The present invention also comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (e.g., endoscopes, articulating and/or non-articulating devices such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) inserted into a body lumen and/or body cavity with respect to the side wall of the body lumen and/or body cavity, whereby to facilitate the precision use of those instruments. 
     Among other things, the present invention comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of endoscopes (and hence also steadying and/or stabilizing the distal tips and/or working ends of other instruments inserted through the working channels of those endoscopes, such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.). 
     And the present invention comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) advanced to the surgical site by means other than through the working channels of endoscopes. 
     And the present invention comprises the provision and use of novel apparatus capable of straightening bends, “ironing out” folds and creating a substantially static or stable side wall of the body lumen and/or body cavity which enables more precise visual examination (including visualization of areas initially hidden or outside the field of view) and/or therapeutic intervention. 
     The Novel Apparatus 
     In accordance with the present invention, and looking now at  FIG. 1 , there is shown novel apparatus  5  which is capable of manipulating (e.g., stabilizing, straightening, expanding and/or flattening, etc.) the side wall of a body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure using an endoscope  10  (e.g., an articulating endoscope), and/or for stabilizing the distal end of endoscope  10  and/or the distal tips and/or working ends of other instruments (e.g., graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc., not shown in  FIG. 1 ). 
     More particularly, apparatus  5  generally comprises a sleeve  15  adapted to be slid over the exterior of the shaft of endoscope  10 , a proximal (or “aft”) balloon  20  (the terms “proximal” and “aft” will hereinafter be used interchangeably) secured to sleeve  15  near the distal end of the sleeve, and a base  25  secured to sleeve  15  at the proximal end of the sleeve. Apparatus  5  also comprises a pair of push tubes  30  slidably mounted to sleeve  15  as will hereinafter be discussed, and a distal (or “fore”) balloon  35  (the terms “distal” and “fore” will hereinafter be used interchangeably) secured to the distal ends of push tubes  30 , such that the spacing between aft balloon  20  and fore balloon  35  can be adjusted by the physician (or other operator or user) by moving push tubes  30  relative to sleeve  15  (e.g., by advancing the two push tubes simultaneously at push tube handle  37 , see below). See  FIGS. 1 and 2-4 . Apparatus  5  also comprises an associated inflation mechanism  40  ( FIG. 1 ) for enabling selective inflation/deflation of one or both of aft balloon  20  and fore balloon  35  by the physician or (or other operator or user). 
     Looking now at  FIGS. 1-6 , sleeve  15  generally comprises an elongated, thin-walled tube configured to be slid over the exterior of the shaft of endoscope  10  (e.g., retrograde from the distal tip of the endoscope) so as to make a close fit therewith, with the sleeve being sized and constructed so that it will slide easily back over the endoscope during mounting thereon (preferably with the scope “dry”) but will have sufficient residual friction (when gripped by the hand of the physician or other operator or user) with the outer surface of the endoscope such that the sleeve will remain in place to allow torqueing (i.e., rotational turning) and pushing/pulling of the endoscope during use (e.g., within the colon of a patient). In one preferred form of the invention, sleeve  15  can move circumferentially to some extent about endoscope  10  (and when gripped securely by the hand of the physician or other operator or user, can rotate in conjunction with the shaft of the endoscope); but sleeve  15  can only move nominally in an axial direction relative to endoscope  10 . Sleeve  15  is sized so that when its distal end is substantially aligned with the distal end of endoscope  10 , sleeve  15  (in conjunction with base  25 ) will substantially cover the shaft of the endoscope. In any case, sleeve  15  is sized so that when it is mounted to endoscope  10  and endoscope  10  is inserted into a patient, sleeve  15  extends out of the body of the patient. In one preferred form of the invention, apparatus  5  is provided according to the particular endoscope with which it is intended to be used, with apparatus  5  being sized so that when base  25  is in engagement with the handle of the endoscope, the distal end of sleeve  15  will be appropriately positioned at the distal end of the endoscope, i.e., substantially aligned with the distal end of the endoscope or slightly proximal to the distal end of the endoscope. 
     If desired, the distal end of sleeve  15  may be provided with a radially-inwardly-extending stop (not shown) to positively engage the distal end surface of endoscope  10 , whereby to prevent the distal end of sleeve  15  from moving proximally beyond the distal end surface of endoscope  10 . Such a radially-inwardly-extending stop can also assist in preventing “torque slip” of sleeve  15  relative to endoscope  10  during torqueing (i.e., rotational turning) of the endoscope while within the colon, and/or “thrust slip” of sleeve  15  relative to endoscope  10  during forward pushing of the endoscope while within the colon. 
     Sleeve  15  preferably has a smooth outer surface so as to be non-traumatic to tissue, and is preferably made of a highly flexible material such that the sleeve will not inhibit bending of the endoscope during use. In one preferred form of the invention, sleeve  15  comprises polyurethane, polyethylene, poly(vinyl chloride) (PVC), polytetrafluoroethylene (PTFE), etc., and is preferably transparent (or at least translucent) so as to allow distance markings on endoscope  10  to be visualized through sleeve  15 . And in one preferred form of the invention, sleeve  15  preferably has nominal hoop strength, so that the physician (or other operator or user) can grip endoscope  10  through sleeve  15 , e.g., so as to torque the scope. If desired, sleeve  15  can include a lubricious coating (e.g., a liquid such as perfluoropolyether synthetic oil, a powder, etc.) on some or all of its interior and/or exterior surfaces, so as to facilitate disposition of the sleeve over the endoscope and/or movement of apparatus  5  through a body lumen and/or body cavity. Alternatively, sleeve  15  may be formed of a material which is itself lubricious, e.g., polytetrafluoroethylene (PTFE), etc. It should be appreciated that the inside surface of sleeve  15  may include features (e.g., ribs) to prevent the sleeve from rotating relative to the endoscope during use. 
     If desired, a vacuum may be “pulled” between sleeve  15  and endoscope  10 , whereby to secure sleeve  15  to endoscope  10  and minimize the profile of sleeve  15 . By way of example but not limitation, a vacuum may be introduced at the proximal end of sleeve  15  (i.e., at base  25 ) or a vacuum may be introduced at a point intermediate sleeve  15 . By way of further example but not limitation, it should also be appreciated that removal of sleeve  15  from endoscope  10  (e.g., at the conclusion of a procedure) may be facilitated by introducing a fluid (e.g., air or a liquid lubricant) into the space between sleeve  15  and endoscope  10 , e.g., at the proximal end of sleeve  15  (i.e., at base  25 ) or intermediate sleeve  15 . 
     Still looking now at  FIGS. 1-6 , aft balloon  20  is secured to sleeve  15  just proximal to the articulating joint of the endoscope near to, but spaced from, the distal end of the sleeve. Aft balloon  20  is disposed concentrically about sleeve  15 , and hence concentrically about an endoscope  10  disposed within sleeve  15 . Thus, aft balloon  20  has a generally toroidal shape. Aft balloon  20  may be selectively inflated/deflated by means of a proximal inflation/deflation tube  45  which has its distal end in fluid communication with the interior of aft balloon  20 , and which has its proximal end in fluid communication with a fitting  46  mounted to base  25 . Fitting  46  is configured for connection to the aforementioned associated inflation mechanism  40 . Fitting  46  is preferably a luer-activated valve, allowing inflation mechanism  40  to be disconnected from fitting  46  without losing pressure in aft balloon  20 . Inflation/deflation tube  45  may be secured to the exterior surface of sleeve  15  or, more preferably, inflation/deflation tube  45  may be contained within a lumen  47  formed within sleeve  15 . 
     Preferably aft balloon  20  is disposed a short distance back from the distal end of sleeve  15 , i.e., by a distance which is approximately the same as the length of the articulating portion of a steerable endoscope  10 , such that the articulating portion of the steerable endoscope will be disposed distal to aft balloon  20  when the steerable endoscope is disposed in sleeve  15 . This construction allows the flexible portion of the steerable endoscope to be articulated even when aft balloon  20  has been inflated in the anatomy so as to stabilize the adjacent non-articulating portion of the endoscope relative to the anatomy, as will hereinafter be discussed in further detail. Thus, when inflated, aft balloon  20  provides a secure platform for maintaining endoscope  10  in a stable position within a body lumen or body cavity, with endoscope  10  centered within the body lumen or body cavity. As a result, endoscope  10  can provide improved visualization of the anatomy. Furthermore, inasmuch as endoscope  10  is securely maintained within the body lumen or body cavity by the inflated aft balloon  20 , instruments advanced through the internal lumens (sometimes referred to as the “working channel” or “working channels”) of endoscope  10  will also be provided with a secure platform for supporting those instruments within the body lumen or body cavity. 
     When aft balloon  20  is appropriately inflated, the aft balloon can atraumatically engage and form a sealing relationship with the side wall of a body lumen within which apparatus  5  is disposed. 
     In one preferred form of the invention, aft balloon  20  is formed out of polyurethane. 
     Base  25  is secured to the proximal end of sleeve  15 . Base  25  engages endoscope  10  and helps secure the entire assembly (i.e., apparatus  5 ) to endoscope  10 . Base  25  preferably comprises a substantially rigid or semi-rigid structure which may be gripped by the physician (or other operator or user) and pulled proximally, whereby to allow the physician (or other operator or user) to pull sleeve  15  over the distal end of endoscope  10  and then proximally back along the length of endoscope  10 , whereby to mount sleeve  15  to the outer surface of the shaft of the endoscope. In one preferred form of the invention, base  25  is pulled proximally along the endoscope until base  25  seats against the handle of the endoscope, thereby prohibiting further proximal movement of base  25  (and hence thereby prohibiting further proximal movement of sleeve  15 ). In one preferred form of the invention, base  25  makes a sealing engagement with endoscope  10 . 
     Push tubes  30  are slidably mounted to sleeve  15 , whereby the distal ends of the push tubes can be extended and/or retracted relative to sleeve  15  (e.g., by advancing or withdrawing the push tubes via push tube handle  37 , see below), and hence extended and/or retracted relative to the distal end of endoscope  10  which is disposed in sleeve  15 . Preferably, push tubes  30  are slidably disposed in support tubes  50  which are secured to the outer surface of sleeve  15  or, more preferably, are contained within lumens  52  formed within sleeve  15 . Support tubes  50  are preferably formed out of a low friction material (e.g., polytetrafluoroethylene, also known as “PTFE”) so as to minimize resistance to movement of push tubes  30  relative to support tubes  50  (and hence minimize resistance to movement of push tubes  30  relative to sleeve  15 ). In this respect it should be appreciated that minimizing resistance to the movement of push tube  30  relative to support tubes  50  improves tactile feedback to the user when push tubes  30  are being used to manipulate fore balloon  35 . In one form of the invention, support tubes  50  are flexible (so as to permit endoscope  10 , and particularly the articulating portion of steerable endoscope  10 , to flex as needed during the procedure); however, support tubes  50  also provide some column strength. Thus, when support tubes  50  are mounted within lumens  52  formed in sleeve  15 , the assembly of sleeve  15  and support tubes  50  is flexible yet has a degree of column strength (whereas sleeve  15  alone is flexible but has substantially no column strength). In the event that push tubes  30  are contained within lumens  52  formed in sleeve  15 , and in the event that support tubes  50  are not disposed between push tubes  30  and lumens  52 , lumens  52  are preferably lubricated so as to minimize friction between push tubes  30  and lumens  52 . 
     The proximal ends of push tubes  30  are connected to push tube handle  37 . As a result of this construction, pushing distally on push tube handle  37  causes the distal ends of push tubes  30  to move distally (at the same rate) relative to sleeve  15  (whereby to move fore balloon  35  distally relative to aft balloon  20 ) and pulling proximally on push tube handle  37  causes the distal ends of push tubes  30  to retract proximally (at the same rate) relative to sleeve  15  (whereby to move fore balloon  35  proximally relative to aft balloon  20 ). Note that by moving push tubes  30  distally or proximally at the same rate, the distal ends of the push tubes are maintained parallel to each other. A clamp  53  ( FIGS. 12 and 15 ) is provided at base  25  for holding push tubes  30  in a selected disposition relative to base  25  (and hence in a selected disposition relative to sleeve  15 ). 
     Push tubes  30  are preferably formed out of a relatively flexible material which provides good column strength, e.g., a thermoplastic polyethylene resin such as Isoplast™ (available from The Lubrizol Corporation of Wickliffe, Ohio), polyethylene, polypropylene, nylon, etc. It should be appreciated that push tubes  30  can comprise a single material or a plurality of materials, and that the stiffness of push tubes  30  can vary along their length. By way of example but not limitation, the distal-most portion of push tubes  30  can be formed of the same material as the remainder of the push tubes but have a lower modulus so as to be more flexible than the remainder of the push tubes, or the distal-most portion of push tubes  30  can comprise a different, more resilient flexible material. By way of example but not limitation, the distal-most portion of push tubes  30  can comprise Nitinol. By way of further example but not limitation, the distal-most portion of push tubes  30  can comprise a stainless steel coil covered with an outer jacket of polytetrafluoroethylene (PTFE), with the distal-most jacket/more-proximal tubing together providing a sealed lumen for inflating/deflating fore balloon  35 . By forming push tubes  30  with distal ends which are more flexible than the remainder of the push tubes, the push tubes  30  and fore balloon  35  can together function as a lead (with a soft atraumatic tip) for apparatus  5  and endoscope  10 , as discussed further below. 
     In one preferred form of the invention, push tubes  30  are configured to maintain a parallel disposition when they are in an unbiased state, i.e., when no force is being applied to push tubes  30 . This is true regardless of the state of inflation or deflation of fore balloon  35 . 
     The distal-most portion of push tubes  30  can be configured to bend inwardly or outwardly if desired. With such a configuration, when the distal tips of push tubes  30  are maintained stationary (e.g., by an inflated fore balloon, as will hereinafter be discussed) and a sufficient distally-directed force is applied to push tubes  30 , the middle portions of push tubes  30  (i.e., the portions between the inflated fore balloon  35  and sleeve  15 ) can bend or bow outwardly, whereby to push outwardly on the side wall of the body lumen which apparatus  5  is disposed in, thereby providing a “tenting” effect on the side wall of the body lumen and/or body cavity in the space between aft balloon  20  and fore balloon  35 . This “tenting” effect can significantly enhance visibility and/or tissue stability in the area distal to endoscope  10 , by pushing outwardly on the side wall of the body lumen and/or body cavity in which apparatus  5  is disposed. 
     It should also be appreciated that by forming push tubes  30  out of a flexible material, it is possible to manually adjust their position during use (e.g., by using a separate tool, by torqueing the apparatus, etc.) so as to prevent the push tubes from interfering with visualization of the patient&#39;s anatomy and/or interfering with diagnostic or therapeutic tools introduced into the space between the fore and aft balloons. By way of example but not limitation, if apparatus  5  is disposed in the anatomy in such a way that a push tube  30  blocks visual or physical access to a target region of the anatomy, the flexible push tube  30  may be moved out of the way by using a separate tool or instrument, or by rotating the apparatus with a torqueing motion so as to move the flexible push tube  30  out of the way, etc. By way of further example but not limitation, by constructing push tubes  30  so that they are circular and flexible and of a diameter significantly smaller than the round circumference of endoscope  10 , the movement of the round endoscope, when articulated, can simply push the push tubes out of the way and provides a unobstructed visual path to the tissue of interest. 
     It should also be appreciated that, if desired, push tubes  30  can be marked with an indicator including distance markers (not shown in the figures), e.g., colored indicators or radiopaque indicators, so that a physician (or other operator or user) observing the surgical site via endoscope  10  or by radiological guidance (e.g., X-ray fluoroscopy) can ascertain the relative disposition of push tubes  30  at the surgical site both longitudinally and/or circumferentially with respect to the side wall of the body lumen and/or other body cavity. 
     As will hereinafter be discussed in further detail, push tubes  30  are hollow, and have their distal ends in fluid communication with the interior of fore balloon  35  ( FIGS. 1-5, 7 and 8 ) and their internal lumens in fluid communication with a fitting  56  mounted to base  25 . Fitting  56  is configured for connection to the aforementioned associated inflation mechanism  40 , in order that fore balloon  35  may be selectively inflated/deflated with air or other fluids (including liquids). Fitting  56  is preferably a luer-activated valve, allowing inflation mechanism  40  to be disconnected from fitting  56  without losing pressure in fore balloon  35 . 
     More particularly, in one preferred form of the present invention, and looking now at  FIG. 8A , push tube handle  37  comprises a hollow interior  57 . Push tubes  30  are mounted to push tube handle  37  so that push tubes  30  will move in conjunction with push tube handle  37 , and so that the hollow interiors of push tubes  30  are in fluid communication with the hollow interior  57  of push tube handle  37 . Push tube handle  37  also comprises a fitting  58  which is in fluid communication with hollow interior  57  of push tube handle  37 . A flexible tube  59  connects fitting  58  with an internal chamber (not shown) in base  25 , with this internal chamber in base  25  being in fluid communication with the aforementioned fitting  56 . As a result of this construction, when push tube handle  37  is moved distally, fore balloon  35  is moved distally, and when push tube handle  37  is moved proximally, fore balloon  35  is moved proximally. 
     Furthermore, when positive fluid pressure is applied to fitting  56  in base  25 , positive fluid pressure is applied to the interior of fore balloon  35 , whereby to inflate fore balloon  35 , and when negative fluid pressure is applied to fitting  56  in base  25 , negative fluid pressure is applied to the interior of fore balloon  35 , whereby to deflate fore balloon  35 . 
     It should be appreciated that the provision of dual push tubes provides numerous advantages. By way of example but not limitation, the provision of dual push tubes provides a symmetric force to fore balloon  35  when the fore balloon is advanced distally into a body lumen, as will hereinafter be discussed. Furthermore, the provision of dual push tubes  30  provides equal outward forces against the adjacent anatomy when the push tubes are employed to straighten out the anatomy in the area proximate the distal end of endoscope  10 , thereby enhancing visualization of, and/or access to, the anatomy, as will hereinafter be discussed. In addition, the provision of dual push tubes ensures that fore balloon  35  remains centered on endoscope  10 , thereby facilitating un-docking of fore balloon  35  from endoscope  10  and re-docking of fore balloon  35  over endoscope  10 , as will hereinafter be discussed. In addition, the provision of dual push tubes  30  helps ensure that fore balloon  35  is stable relative to the tip of the endoscope, minimizing rotational movement of the fore balloon when inflated. Furthermore, the provision of dual hollow push tubes provides a redundant air transfer system for inflating or deflating fore balloon  35 . 
     Fore balloon  35  is secured to the distal ends of push tubes  30 , whereby the spacing between aft balloon  20  and fore balloon  35  can be adjusted by moving push tubes  30  relative to sleeve  15 , i.e., by moving push tube handle  37  relative to sleeve  15 . Furthermore, hollow push tubes  30  provide a conduit between the interior of fore balloon  35  and fitting  56 , whereby to permit selective inflation/deflation of fore balloon  35  via fitting  56 . 
     Significantly, fore balloon  35  is configured so that (i) when it is deflated (or partially deflated) and it is in its “retracted” position relative to sleeve  15  ( FIG. 2 ), fore balloon  35  provides an axial opening  63  ( FIGS. 7, 8 and 10 ) sufficient to accommodate sleeve  15  and the shaft of endoscope  10  therein, whereby fore balloon  35  can be “docked” over sleeve  15  and endoscope  10 , and (ii) when fore balloon  35  is in its “extended” position relative to sleeve  15  and is appropriately inflated ( FIG. 4 ), axial opening  63  is closed down (and preferably completely closed off). At the same time, when appropriately inflated, the fore balloon can atraumatically engage and form a sealing relationship with the side wall of a body lumen and/or body cavity within which apparatus  5  is disposed. Thus, when fore balloon  35  is appropriately inflated, the fore balloon can effectively seal the body lumen and/or body cavity distal to fore balloon  35 , by closing down axial opening  63  and forming a sealing relationship with the side wall of the body lumen and/or body cavity within which apparatus  5  is disposed. In this way, when push tubes  30  are advanced distally so as to separate fore balloon  35  from aft balloon  20 , and when fore balloon  35  and aft balloon  20  are appropriately inflated, the two balloons will create a sealed zone therebetween (sometimes hereinafter referred to as “the therapeutic zone”). 
     It will be appreciated that, when fore balloon  35  is reconfigured from its deflated condition to its inflated condition, fore balloon  35  expands radially inwardly (so as to close down axial opening  63 ) as well as radially outwardly (so as to engage the surrounding tissue). 
     Thus it will be seen that fore balloon  35  has a “torus” shape when deflated (to allow it to seat over the distal end of the endoscope) and a substantially “solid” shape when inflated (to allow it to close off a body lumen or body cavity). To this end, and looking now at  FIGS. 9 and 10 , fore balloon  35  is preferably manufactured as a single construct comprising a body  67  having a proximal opening  69  and a distal opening  71 , a proximal extension  73  having a “key-shaped” cross-section comprising lobes  74 , and a distal extension  76  having a circular cross-section. Note that lobes  74  are disposed on proximal extension  73  with a configuration which matches the configuration of push tubes  30  (i.e., where apparatus  5  comprises two push tubes  30  diametrically opposed to one another, proximal extension  73  will comprise two lobes  74  diametrically opposed to one another; where apparatus  5  comprises three push tubes  30  equally-circumferentially-spaced about the perimeter of sleeve  15 , proximal extension  73  will comprise three lobes  74  equally-circumferentially-spaced about the perimeter of proximal extension  73 ; where apparatus  5  comprises one push tube  30 , proximal extension  73  will comprise one lobe  74 , etc.—for the purposes of the present invention, proximal extension  73  and lobe(s)  74  may be collectively referred to as having a “key-shaped” cross-section). During assembly, push tubes  30  are seated in lobes  74  of proximal extension  73 , proximal extension  73  is everted into the interior of body  67  (with the interiors of hollow push tubes  30  being in fluid communication with the interior of body  67 ), and then distal extension  76  is everted into the interior of proximal extension  73 , whereby to provide a fore balloon  35  having axial opening  63  extending therethrough, with push tubes  30  being secured to fore balloon  35  and communicating with the interior of fore balloon  35 . Significantly, axial opening  63  is sized to receive the distal end of endoscope  10  therein. Also significantly, the formation of fore balloon  35  by the aforementioned process of everting proximal extension  73  into the interior of body  67 , and then everting distal extension  76  into the interior of proximal extension  73 , provides multiple layers of balloon material around push tubes  30 , thereby providing a more robust balloon construction. Among other things, providing multiple layers of balloon material around push tubes  30  adds cushioning to the distal ends of push tubes  30 , thereby providing an even more atraumatic distal tip to push tubes  30  and further ensuring that the distal tips of push tubes  30  do not damage the adjacent tissue. 
     In one preferred form of the invention, fore balloon  35  is formed out of polyurethane. 
     It should be appreciated that when fore balloon  35  is in its deflated condition, the material of fore balloon  35  substantially encompasses the distal ends of push tubes  30  (while still allowing push tubes  30  to be in fluid communication with the interior of fore balloon  35 ), thereby providing an atraumatic tip for advancing fore balloon  35  distally through a body lumen. Furthermore, push tubes  30  and the deflated fore balloon  35  can, together, essentially function as a soft-tipped lead for apparatus  5  and endoscope  10 , as discussed further below ( FIG. 20 ). 
     If desired, one or both of aft balloon  20  and fore balloon  35  can be marked with an indicator (e.g., a color indicator or a radiopaque indicator) so that a physician (or other operator or user) observing the surgical site via endoscope  10  or radiological guidance (e.g., X-ray fluoroscopy) can ascertain the disposition of one or both of the balloons at the surgical site. 
     Inflation mechanism  40  provides a means to selectively inflate aft balloon  20  and/or fore balloon  35 . 
     In one preferred form of the present invention, and looking now at  FIGS. 1 and 11 , inflation mechanism  40  comprises a single-line syringe inserter  140  comprising a body  145  and a plunger  150 . Preferably a spring  153  is provided in body  145  to automatically return plunger  150  at the end of its stroke. Syringe inserter  140  is connected to one or the other of fittings  46 ,  56  via a line  155 . Thus, with this construction, when single-line syringe inserter  140  is to be used to inflate aft balloon  20 , syringe inserter  140  is connected to fitting  46  via line  155  so that the output of single-line syringe inserter  140  is directed to aft balloon  20  (i.e., via proximal inflation/deflation tube  45 ). Correspondingly, when single-line syringe inserter  140  is to be used to inflate fore balloon  35 , syringe inserter  140  is connected to fitting  56  via line  155  so that the output of single-line syringe inserter  140  is directed to fore balloon  35  (i.e., via flexible tube  59  and the hollow interiors of push tubes  30 ). 
     In another preferred form of the present invention, inflation mechanism  40  comprises an elastic bulb  156  having a first port  157  and a second port  158 . A one-way valve  159  (e.g., a check valve) is disposed in first port  157  so that air can only pass through first port  157  when traveling in an outward direction. Another one-way valve  159  (e.g., a check valve) is disposed in second port  158  so that air can only pass through second port  158  when traveling in an inward direction. When elastic bulb  156  is compressed (e.g., by hand), air within the interior of elastic bulb  156  is forced out first port  157 ; and when elastic bulb  156  is thereafter released, air is drawn back into the interior of elastic bulb  156  through second port  158 . 
     As a result of this construction, when elastic bulb  156  is to be used to inflate aft balloon  20 , first port  157  is connected to fitting  46  via line  155  so that the positive pressure output of elastic bulb  156  is directed to aft balloon  20 . Elastic bulb  156  may thereafter be used to deflate aft balloon  20 , i.e., by connecting second port  158  to fitting  46  via line  155  so that the suction of elastic bulb  156  is directed to aft balloon  20 . Correspondingly, when elastic bulb  156  is to be used to inflate fore balloon  35 , first port  157  is connected to fitting  56  via line  155  so that the positive pressure output of elastic bulb  156  is directed to fore balloon  35 . Elastic bulb  156  may thereafter be used to deflate fore balloon  35 , i.e., by connecting second port  158  to fitting  56  via line  155  so that the suction of elastic bulb  156  is directed to fore balloon  35 . 
     Alternatively, and looking now at  FIGS. 12 and 13 , a syringe  160  may be used to inflate aft balloon  20  and/or fore balloon  35 . Inflation mechanism  160  comprises a body  161  and a plunger  162 . Preferably a spring (not shown) is provided in body  161  to automatically return plunger  162  at the end of its power stroke. Syringe  160  is connected to fittings  46 ,  56  via a line  163 . With this construction, syringe  160  comprises a valve  165  for connecting syringe  160  to fore balloon  35  or aft balloon  20 , and a valve  170  for selecting inflation or deflation of the connected-to balloon. 
     Thus, with this construction, when syringe  160  is to be used to inflate aft balloon  20 , valve  165  (a two-position valve that connects valve  170  to either the fore balloon or the aft balloon) is set so that the syringe  160  is connected through fitting  46  to aft balloon  20 , and valve  170  (a 2-way crossover valve which allows the one-way valves to be arranged to inflate in one configuration and deflate in the other configuration) is set so that syringe  160  is providing inflation pressure. Thereafter, when aft balloon  20  is to be deflated, valve  170  is set to its deflate position. 
     Correspondingly, when syringe  160  is to be used to inflate fore balloon  35 , valve  165  is set so that syringe  160  is connected through fitting  56  to fore balloon  35 , and valve  170  is set so that syringe  160  is providing inflation pressure. Thereafter, when fore balloon  35  is to be deflated, valve  170  is set to its deflate position. 
     In yet another form of the invention, inflation mechanism  40  may comprise an automated source of fluid pressure (either positive or negative), e.g., an electric pump. 
     If desired, and looking now at  FIG. 14 , a relief valve  175  can be connected to the inflation/deflation line which connects to fore balloon  35  so as to ensure that the pressure within fore balloon  35  does not exceed a predetermined level. Similarly, and still looking now at  FIG. 14 , a relief valve  180  can be connected to the inflation/deflation line which connects to aft balloon  20  so as to ensure that the pressure within aft balloon  20  does not exceed a predetermined level. 
     Alternatively, and/or additionally, one or more pressure gauges  182  ( FIG. 1  or  FIG. 13 ) may be incorporated into the fluid line connected to aft balloon  20 , and/or the fluid line connected to fore balloon  35 , whereby to provide the physician (or other operator or user) with information relating to the pressure inside aft balloon  20  and/or fore balloon  35  so as to avoid over inflation and/or to help the physician (or other operator or user) ascertain the inflation state of a balloon during a procedure. 
     Furthermore, it will be appreciated that as fore balloon  35  moves between its “retracted” position ( FIG. 2 ) and its “extended” position ( FIG. 4 ), the flexible tube  59  connecting push tubes  30  to base  25  (and hence to fitting  56 ) may gather about base  25 , potentially interfering with the physician&#39;s (or other operator&#39;s or user&#39;s) actions. Accordingly, if desired, and looking now at  FIG. 15 , a flexible tube retraction system  185  may be provided (e.g., within base  25 ) to take up slack in flexible tube  59  when fore balloon  35  is extended. 
     Preferred Method of Using the Novel Apparatus 
     Apparatus  5  may be used to manipulate, (e.g., stabilize, straighten, expand and/or flatten, etc.) the side wall of a body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure using endoscope  10 , and/or to stabilize the distal tips and/or working ends of instruments (e.g., graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.), e.g., advanced into the therapeutic zone. 
     More particularly, in use, sleeve  15  is first mounted to endoscope  10  ( FIG. 1 ). This may be accomplished by pulling base  25  proximally over the distal end of endoscope  10  and then pulling proximally along the length of endoscope  10  until the distal end of sleeve  15  is substantially aligned with the distal tip of endoscope  10 . At this point, aft balloon  20  is deflated, fore balloon  35  is deflated, and fore balloon  35  is docked over the distal end of endoscope  10 . Endoscope  10  and apparatus  5  are ready to be inserted as a unit into the patient. 
     Looking next at  FIG. 16 , endoscope  10  and apparatus  5  are inserted as a unit into a body lumen and/or body cavity of the patient. By way of example but not limitation, endoscope  10  and apparatus  5  are inserted as a unit into the gastrointestinal (GI) tract of the patient. Endoscope  10  and apparatus  5  are advanced along the body lumen and/or body cavity to a desired location within the patient ( FIGS. 17 and 18 ). 
     When apparatus  5  is to be used (e.g., to manipulate the side wall of the gastrointestinal tract so as to provide increased visualization of the same and/or increase access to the same, and/or for stabilizing instruments relative to the same), aft balloon  20  is inflated so as to stabilize apparatus  5  (and hence endoscope  10 ) within the body lumen and/or body cavity. See  FIG. 19 . This may be done using the aforementioned associated inflation mechanism  40 . 
     In this respect it will be appreciated that inasmuch as the articulating portion of the endoscope resides distal to aft balloon  20 , the endoscope will be able to articulate distal to aft balloon  20  so as to facilitate visualization of the anatomy even after aft balloon  20  is inflated. Significantly, such visualization is enhanced, inasmuch as aft balloon  20  stabilizes endoscope  10  within the gastrointestinal tract and distends the colon and increases the colon to a fixed diameter directly adjacent to aft balloon  20 . 
     Next, push tubes  30  are advanced distally in the body lumen and/or body cavity (i.e., so as to move fore balloon  35  further ahead of aft balloon  20 ) by pushing distally on push tube handle  37 . Thus, push tubes  30 , and hence fore balloon  35 , move distally relative to endoscope  10  (which is stabilized in position within the gastrointestinal tract by the inflated aft balloon  20 ). Note that the deflated fore balloon  35  covers the distal ends of push tubes  30  during such distal advancement of fore balloon  35 , thereby ensuring atraumatic advancement of fore balloon  35 . Note that atraumatic advancement of fore balloon  35  may be further enhanced by forming the distal ends of push tubes  30  out of a more resilient material. 
     When push tubes  30  have advanced fore balloon  35  to the desired position distal to endoscope  10 , fore balloon  35  is inflated ( FIG. 20 ) so as to secure fore balloon  35  to the anatomy. Again, this may be done using the aforementioned associated inflation mechanism  40 . As fore balloon  35  is inflated, the inflated fore balloon  35 , the inflated aft balloon  20 , and push tubes  30  will all complement one another so as to stabilize, straighten, expand and/or flatten the side wall of the body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure using endoscope  10 . In this respect it will be appreciated that the inflated fore balloon  35  and the inflated aft balloon  20  will together expand and tension the side wall of the body lumen and/or body cavity, and push tubes  30  will tend to straighten the anatomy between the two inflated balloons when the fore balloon is extended distally from the aft balloon. In this respect it will also be appreciated that once aft balloon  20  and fore balloon  35  have both been inflated, fore balloon  35  will create a substantially full-diameter seal across the body lumen and/or body cavity (because the inflated fore balloon closes down the axial opening  63  extending through the fore balloon when the fore balloon is in its deflated state), and aft balloon  20  will cooperate with sleeve  15  and endoscope  10  to create another substantially full-diameter barrier across the body lumen and/or body cavity. Thus, the inflated fore balloon  35  and the inflated aft balloon  20  will together define a substantially closed region along the body lumen and/or body cavity (i.e., an isolated therapeutic zone which prevents the passage of fluid and/or other liquids by virtue of the air-tight seals established by the inflated fore balloon  35  and aft balloon  20 ). The side wall of the body lumen and/or body cavity will be tensioned by inflation of fore balloon  35  and aft balloon  20 , whereby to better present the side wall of the body lumen and/or body cavity for viewing through endoscope  10 . 
     It should be appreciated that the expansion and tensioning of the side wall of the body lumen and/or body cavity effected by the inflated fore balloon  35 , the inflated aft balloon  20 , and push tubes  30 , can be further enhanced by advancing the fore balloon when it is inflated and gripping the side wall of the body lumen and/or body cavity, whereby to tension the side wall of the body lumen and/or body cavity. 
     Significantly, inasmuch as the inflated fore balloon  35  and the inflated aft balloon  20  together define a substantially closed region along the body lumen and/or body cavity (i.e., an isolated therapeutic zone), this region can then be inflated ( FIG. 21 ) with a fluid (e.g., air, CO 2 , etc.) so as to further tension the side wall of the body lumen and/or body cavity, whereby to better present the side wall of the body lumen and/or body cavity for viewing through endoscope  10  and stabilize the side wall so as to facilitate more precise therapeutic interventions. If desired, fore balloon  35  can be retracted toward aft balloon  20  (i.e., by pulling push tube handle  37  proximally), while remaining inflated (and hence maintaining a grip on the side wall of the body lumen and/or body cavity), so as to move the visible mucosa and further improve visualization and access (see  FIG. 22 ), e.g., so as to position a particular target area on the side wall of the body lumen and/or body cavity at a convenient angle relative to the endoscope and endoscopic tools. 
     Alternatively, if desired, once aft balloon  35  has been inflated, push tubes  30  may be advanced distally a portion—but only a portion—of their full distal stroke, then fore balloon  35  may be inflated so as to grip the side wall of the body lumen and/or body cavity, and then push tubes  30  may be further advanced distally. This action will cause flexible push tubes  30  to bow outwardly (see  FIGS. 22A-22D ), contacting the side wall of the body lumen and/or body cavity and pushing the side wall of the body lumen and/or body cavity outwardly, e.g., in a “tenting” fashion, whereby to further enhance visualization of the side wall of the body lumen and/or body cavity by endoscope  10 . 
     If desired, instruments  190  ( FIG. 23 ) may be advanced through working channels of endoscope  10  so as to biopsy and/or treat pathologic conditions (e.g., excise pathological anatomy). It will be appreciated that such instruments will extend through the distal end of the endoscope, which is effectively stabilized relative to the anatomy via aft balloon  20 , so that the working ends of instruments  190  will also be highly stabilized relative to the anatomy. This is a significant advantage over the prior art practice of advancing instruments out of the non-stabilized end of an endoscope. Preferably instruments  190  include articulating instruments having a full range of motion, whereby to better access target anatomy. 
     Furthermore, if bleeding were to obscure a tissue site, or if bleeding were to occur and the surgeon is unable to identify the source of the bleeding, the isolated therapeutic zone permits rapid flushing of the anatomic segment in which the therapeutic zone lies (e.g., with a liquid such as saline) with rapid subsequent removal of the flushing liquid (see  FIGS. 24-26 ). 
     Also, if desired, fore balloon  35  can be directed with high precision to a bleeding site, whereupon fore balloon  35  may be used (e.g., inflated) to apply local pressure to the bleeding site in order to enhance bleeding control (see  FIG. 27 ). This can be done under the visualization provided by endoscope  10 . 
     If it is desired to reposition endoscope  10  within the anatomy with minimal interference from apparatus  5 , fore balloon  35  is returned to its torus configuration (i.e., partially deflated), the fore balloon is retracted proximally and “re-docked” on the distal end of endoscope  10 , aft balloon  20  is deflated, and then endoscope  10  (with apparatus  5  carried thereon) is repositioned within the anatomy. Note that where fore balloon  35  is to be re-docked on the distal end of endoscope  10 , fore balloon  35  is preferably only partially deflated until fore balloon  35  is re-docked on the distal end of the endoscope, since partial inflation of fore balloon  35  can leave fore balloon  35  with enough “body” to facilitate the re-docking process. Thereafter, fore balloon  35  may be fully deflated if desired, e.g., so as to positively grip the distal end of endoscope  10 . 
     Alternatively, if desired, fore balloon  35  may be used as a drag brake to control retrograde motion of the endoscope. More particularly, in this form of the invention, endoscope  10  and apparatus  5  are first advanced as a unit into the body lumen and/or body cavity until the tip of the endoscope is at the proper location. Next, aft balloon  20  is inflated, push tubes  30  are advanced distally, and then fore balloon  35  is inflated ( FIG. 28 ). Visualization and, optionally, therapeutic treatment may then be effected at that location. When the apparatus is to be moved retrograde, aft balloon  20  is deflated, fore balloon  35  is partially deflated, and then the endoscope is withdrawn proximally, dragging the semi-inflated fore balloon  35  along the body lumen and/or body cavity ( FIG. 29 ), with fore balloon  35  acting as something of a brake as the endoscope is pulled proximally, thereby enabling more controlled retrograde movement of the endoscope and hence better visualization of the anatomy. If at some point it is desired, aft balloon  20  and fore balloon  35  can be re-inflated, as shown in  FIG. 30 , with or without introduction of a fluid into the “isolated therapeutic zone” established between the two balloons, so as to stabilize, straighten, expand and/or flatten the anatomy. 
     It is also possible to use aft balloon  20  as a brake when withdrawing the endoscope (and hence apparatus  5 ) from the anatomy, either alone or in combination with the aforementioned braking action from fore balloon  35 . 
     At the conclusion of the procedure, endoscope  10  and apparatus  5  are withdrawn from the anatomy. Preferably this is done by deflating (or partially deflating) fore balloon  35 , retracting push tubes  30  so that fore balloon  35  is “re-docked” onto the distal end of endoscope  10 , fully deflating fore balloon  35  so that it grips the distal end of the endoscope, deflating aft balloon  20  (if it is not yet deflated), and then withdrawing endoscope  10  and apparatus  5  as a unit from the anatomy. 
     It should be appreciated that apparatus  5  may also be used advantageously in various ways other than those disclosed above. By way of example but not limitation, when endoscope  10  (and apparatus  5 ) is to be advanced within the colon, it may be desirable to first project fore balloon  35  distally under visual guidance of the endoscope so that fore balloon  35  leads the distal end of the endoscope. As a result, when the endoscope is advanced distally, with fore balloon  35  being deflated (or partially deflated), the fore balloon and flexible push tubes  30  may act as an atraumatic lead (guiding structure) for the endoscope as the endoscope advances through the colon. Significantly, inasmuch as the distal ends of push tubes  30  are preferably highly flexible, as the advancing fore balloon  35  encounters the colon wall (e.g., at a turn of the colon), the flexible push tubes can deflect so that the fore balloon tracks the path of the colon, thereby aiding atraumatic advancement of the endoscope along the colon. It should also be appreciated that apparatus  5  may also be used advantageously in other ways to facilitate further examinations of the luminal surface otherwise difficult to be performed currently. Such an example is endoscopic ultrasound examination of the lumen which would be facilitated by the fluid-filled inflated fore balloon and ultrasound probe examination. 
     Additional Constructions 
     If desired, apparatus  5  may be constructed so that push tubes  30  may be advanced or retracted independently of one another, as well as in conjunction with one another—such independent advancement or retraction of push tubes  30  can aid in steering the partially- or fully-deflated fore balloon  35  through the body lumen and/or body cavity, whereby to facilitate advancement or retraction of endoscope  10  through the body lumen and/or body cavity, and/or such independent advancement or retraction of push tubes  30  can facilitate applying a “turning force” to the anatomy with an inflated fore balloon  35 , whereby to better present the anatomy for visualization and/or treatment. 
     By way of example but not limitation, in this form of the invention, and looking now at  FIG. 30A , push tubes  30  are each independently slidably mounted to push tube handle  37  so that push tubes  30  can move independently of push tube handle  37  and each other. Stops  191  limit distal movement of push tubes  30  relative to push tube handle  37  so that a push tube cannot be moved completely out of push tube handle  37 . As a result of this construction, when fore balloon  35  is to be moved distally, push tubes  30  are moved distally, either together or independently of one another. And when fore balloon  35  is to be moved proximally, push tubes  30  are moved proximally, either together or independently of one another. At any point in a procedure, push tubes  30  can be moved independently of one another so as to “turn” the fore balloon, e.g., such as when fore balloon  35  is inflated and engaging the anatomy, whereby to apply a “turning force” to the anatomy, or where fore balloon  35  is partially inflated and is being used as an atraumatic tip for the advancing assembly, whereby to help “steer” the assembly through the anatomy. Note that it may be desirable to provide a limiting mechanism to limit the extent to which push rods  30  may be moved, longitudinally, independently of one another, in order to prevent excessive turning of fore balloon  35 , and/or push rod cross-over, and/or push rod entanglement, and/or push rod misalignment, etc. Note also that push tubes  30  may be held in a particular disposition by mounting push tubes  30  in the aforementioned clamp  53  ( FIGS. 12 and 15 ). 
     It should also be appreciated that it is possible to modify the construction of sleeve  15  so as to support instruments (or hollow instrument guide tubes) external to endoscope  10 . More particularly, looking again at  FIGS. 5 and 6 , it will be seen that in the construction shown in  FIGS. 5 and 6 , sleeve  15  comprises a lumen  47  for receiving inflation/deflation tube  45  for inflating/deflating aft balloon  20 , and a pair of lumens  52  for receiving support tubes  50  which receive push tubes  30  for manipulating and inflating/deflating fore balloon  35 . However, if desired, sleeve  15  may include additional lumens for supporting instruments (or hollow instrument guide tubes) external to endoscope  10 . 
     More particularly, and looking now at  FIG. 31 , there is shown an end view of another form of sleeve  15  which includes a plurality of lumens  195  for slidably receiving instruments  190  therein. Note that, when inflated, aft balloon  20  provides a secure platform for maintaining endoscope  10  and sleeve  15  within a body lumen or body cavity, with endoscope  10  and sleeve  15  centered within the body lumen or body cavity. As a result, the distal ends of lumens  195  of sleeve  15  will also be securely maintained within the body lumen or body cavity so as to provide a secure support for instruments advanced through lumens  195  of sleeve  15 . 
     The proximal ends of lumens  195  may extend to, and through, base  25 , in which case instruments may be inserted into lumens  195  at base  25 , or the proximal ends of lumens  195  may terminate proximal to base  25  (but still outside the body of the patient), in which case instruments may be inserted into lumens  195  intermediate sleeve  15 . By way of example but not limitation, where endoscope  10  is 180 cm in length and instruments  190  are 60 cm in length, it can be advantageous to insert instruments  190  into lumens  195  at a point closer to balloons  20 ,  35  (rather than at base  25 ). Note that in  FIG. 31 , the lumen  47  for receiving inflation/deflation tube  45  and inflation/deflation tube  45  for inflating/deflating aft balloon  20  are not visible, since the view is distal-facing and is taken at a location distal to where lumen  47  and inflation/deflation tube  45  terminate on sleeve  15 . 
       FIGS. 32-35  show various instruments  190  extending out of lumens  195 . Note that instruments  190  preferably comprise articulating instruments, e.g., graspers  190 A in  FIGS. 32-35 , a cauterizing device  190 B in  FIGS. 32-33 , scissors  190 C in  FIGS. 34 and 35 , and a suction device  190 D in  FIGS. 32-35 . 
     It should be appreciated that where sleeve  15  comprises its central passageway for receiving endoscope  10 , lumen  47  for receiving inflation/deflation tube  45 , lumens  52  for receiving support tubes  50  which receive push tubes  30 , and/or lumens  195  for slidably receiving instruments  190  therein, sleeve  15  is preferably formed by an extrusion process. 
     In one preferred form of the invention, lumen  47  for receiving inflation/deflation tube  45 , lumens  52  for receiving support tubes  50  which receive push tubes  30 , and/or lumens  195  for slidably receiving instruments  190  may have a fixed configuration (i.e., a fixed diameter), so that sleeve  15  has a fixed outer profile. 
     In another preferred form of the invention, lumen  47  for receiving inflation/deflation tube  45 , lumens  52  for receiving support tubes  50  which receive push tubes  30 , and/or lumens  195  for slidably receiving instruments  190  may have an expandable configuration (i.e., they may have a minimal profile when empty and expand diametrically as needed when filled), so that the overall profile of sleeve  15  is minimized. 
     It should also be appreciated that where sleeve  15  comprises a plurality of lumens  195  for slidably receiving instruments  190  therein, it can be desirable to provide greater structural integrity to the distal ends of lumens  195  so as to provide improved support for the instruments  190  received within lumens  195 . To this end, a support ring may be provided at the distal end of sleeve  15 , wherein the support ring provides openings for the passage of push tubes  30  and openings for the passage of instruments  190 . Note that the openings in such a support ring for the passage of instruments  190  preferably make a close fit with the instruments so as to provide excellent instrument support at the distal end of sleeve  15 . 
     Alternatively and/or additionally, lumens  195  may accommodate hollow instrument guide tubes which themselves accommodate instruments therein. Such hollow instrument guide tubes can provide greater structural integrity to the distal ends of lumens  195  so as to provide improved support for the instruments  190  received within lumens  195 . And such hollow instrument guide tubes may be of fixed geometry or of bendable or articulating geometry. See, for example,  FIG. 36 , which shows hollow instrument guide tubes  200  extending out of lumens  195  and receiving instruments  190  therein. Note that hollow instrument guide tubes  200  may be independently movable relative to one another (and independently movable relative to sleeve  15 ). Note also that instruments  190  preferably make a close fit with hollow instrument guide tubes  200  so as to provide excellent instrument support at the distal end of sleeve  15 . 
     It should also be appreciated that, if desired, the two push tubes  30  may be replaced by a single push tube  30  or by more than two push tubes  30 , e.g., by three push tubes  30 . It will be appreciated that, where a plurality of push tubes  30  are provided, it will generally be desirable to equally-circumferentially-space the push tubes from one another, e.g., where two push tubes  30  are provided, it is generally desirable that the two push tubes  30  be spaced 180 degrees apart, where three push tubes  30  are provided, it is generally desirable that the push tubes be spaced 120 degrees apart, etc. 
     Applications 
     Thus it will be seen that the present invention comprises the provision and use of novel apparatus for manipulating the side wall of a body lumen and/or body cavity so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure, e.g., to straighten bends, “iron out” inner luminal surface folds and create a substantially static or stable side wall of the body lumen and/or body cavity which enables more precise visual examination (including visualization of areas initially hidden or outside the field of view) and/or therapeutic intervention. By way of example but not limitation, the novel apparatus can be used to stabilize, straighten, expand and/or flatten bends and/or curves and/or folds in the side wall of the intestine so as to better present the side wall tissue (including visualization of areas initially hidden or outside the field of view) for examination and/or treatment during an endoscopic procedure. 
     The present invention also comprises the provision and use of novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (e.g., endoscopes, articulating and/or non-articulating devices such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) inserted into a body lumen and/or body cavity during an endoscopic procedure with respect to the side wall of the body lumen and/or body cavity, whereby to facilitate the precision use of those instruments. 
     By way of example but not limitation, the present apparatus can provide a stable platform (i.e., a stable endoscope, stable therapeutic tools and a stable colon wall, all stable with respect to one another) for the performance of numerous minimally-invasive procedures within a body lumen and/or body cavity, including the stabilization of an endoscope and/or other surgical instruments (e.g., graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) within the body lumen and/or body cavity, e.g., during a lesion biopsy and/or lesion removal procedure, an organ resection procedure, endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR), etc., while at the same time stabilizing the colon (including decreasing deformation of the colon wall) so as to enable more precise visualization, intervention and/or surgery. 
     Significantly, the present invention provides novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of endoscopes (and hence also steadying and/or stabilizing the distal tips and/or working ends of other instruments inserted through the working channels of those endoscopes, such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) with respect to the side wall of the body lumen and/or body cavity, and stabilizing the side wall of the body lumen and/or body cavity relative to these instruments. 
     And the present invention provides novel apparatus capable of steadying and/or stabilizing the distal tips and/or working ends of instruments (such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) advanced to the surgical site by means other than through the working channels of endoscopes. 
     The novel apparatus of the present invention can be used in substantially any endoscopic procedure to facilitate the alignment and presentation of tissue during an endoscopic procedure and/or to stabilize the working end of an endoscope (and/or other instruments advanced through the endoscope) relative to tissue or to assist in the advancement of the endoscope during such a procedure. 
     The present invention is believed to have widest applications with respect to the gastrointestinal (GI) tract (e.g., large and small intestines, esophagus, stomach, etc.), which is generally characterized by frequent turns and which has a side wall characterized by numerous folds and disease processes located on and between these folds. However, the methods and apparatus of the present invention may also be used inside other body lumens (e.g., blood vessels, lymphatic vessels, the urinary tract, fallopian tubes, bronchi, bile ducts, etc.) and/or inside other body cavities (e.g., the head, chest, abdomen, nasal sinuses, bladder, cavities within organs, etc.). 
     Methods and Apparatus for Inverting a Hollow Sleeve and Thereafter Reverting an Inverted Hollow Sleeve 
     As can be seen in  FIGS. 1-36  above, apparatus  5  is provided for steadying and/or stabilizing the distal tips and/or working ends of endoscopes (and hence also steadying and/or stabilizing the distal tips and/or working ends of other instruments inserted through the working channels of those endoscopes, such as graspers, cutters or dissectors, cauterizing tools, ultrasound probes, etc.) with respect to the side wall of the body lumen and/or body cavity, and stabilizing the side wall of the body lumen and/or body cavity relative to these instruments. 
     Apparatus  5  generally comprises a sleeve  15  adapted to be slid over the exterior of the shaft of endoscope  10 , a proximal (or “aft”) balloon  20  secured to sleeve  15  near the distal end of the sleeve, and a base  25  secured to sleeve  15  at the proximal end of the sleeve. Apparatus  5  also comprises a pair of push tubes  30  slidably mounted to sleeve  15 , and a distal (or “fore”) balloon  35  secured to the distal ends of push tubes  30 , such that the spacing between aft balloon  20  and fore balloon  35  can be adjusted by the physician (or other operator or user) by moving push tubes  30  relative to sleeve  15  (e.g., by advancing the two push tubes simultaneously at push tube handle  37 , see below). 
     As can be seen in  FIGS. 1-6 , sleeve  15  generally comprises an elongated, thin-walled tube configured to be slid over the exterior of the shaft of endoscope  10  (e.g., retrograde from the distal tip of the endoscope) so as to make a close fit therewith, with the sleeve being sized and constructed so that it will slide easily back over the endoscope during mounting thereon (preferably with the scope “dry”) but will have sufficient residual friction (when gripped by the hand of the physician or other operator or user) with the outer surface of the endoscope such that the sleeve will remain in place to allow torqueing (i.e., rotational turning) and pushing/pulling of the endoscope during use (e.g., within the colon of a patient). 
     As also stated above, sleeve  15  may include a lubricious coating (e.g., a liquid such as perfluoropolyether synthetic oil, a powder, a hydrophilic coating, etc.) on some or all of its interior and/or exterior surfaces, so as to facilitate disposition of the sleeve over the endoscope and/or movement of apparatus  5  through a body lumen and/or body cavity. 
     Some types of coatings (e.g., hydrophilic coatings) require ultraviolet (UV) light to cure the coating to the interior and/or exterior surface of the sleeve. However, when certain hydrophilic coatings are applied to the interior surface of sleeve  15 , the UV light cannot penetrate through the sleeve material, and the hydrophilic coating does not properly cure on the interior surface of the sleeve, thereby preventing the hydrophilic coating from properly bonding to the interior of sleeve  15 . Failure of the hydrophilic coating to properly bond to the interior of sleeve  15  could result in the dislodging of the hydrophilic coating when an endoscope is advanced through sleeve  15 , thereby making it more difficult for the endoscope to be advanced through the sleeve. 
     The present invention comprises the provision and use of a novel apparatus and method for inverting sleeve  15  so that a hydrophilic coating can be applied to the interior of the sleeve, and a novel apparatus and method for reverting sleeve  15  after the hydrophilic coating has been applied to the interior of sleeve  15  and allowed to cure on the interior of sleeve  15 . 
     Inversion Fixture for Inverting Sleeve  15  and Support Tubes  50   
     Looking now at  FIGS. 37-41 , there is shown a novel inversion fixture  500  for inverting sleeve  15  and support tubes  50  (i.e., the tubes which receive push tubes  30  of sleeve  15 ) ( FIG. 42 ). 
     Inversion fixture  500  generally comprises a hollow tube  505  having a proximal end  510  and a distal end  515 , and a clamping rod  520  configured to move within hollow tube  505  so that when sleeve  15  is disposed over hollow tube, proximal movement of clamping rod  520  will clamp distal end  17  of sleeve  15  to distal end  515  of hollow tube, as will be discussed in further detail below, so that sleeve  15  can thereafter be pulled distally over hollow tube  505  to invert sleeve  15 . 
     More particularly, clamping rod  520  comprises a proximal end  525  and a distal end  530 , with the proximal end of clamping rod  520  being connected to a first clamp  535  (e.g., a push/pull toggle clamp), and the distal end of clamping rod  520  comprising a sleeve plug  540 . A pair of flexible mandrels  545  ( FIG. 44 ) extend from distal end  530  of clamping rod  520 , through each support tube  50 , and freely out of the proximal ends of support tubes  50 , for maintaining the geometry of the lumen of the support tube, thus preventing excessive eccentricity, kinking and other deformations from occurring during the inversion process, which could compromise the final function of support tube  50 . When actuated, first clamp  535  is configured to pull clamping rod  520  proximally, whereby to pull sleeve plug  540  of clamping rod  520  into distal end  515  of hollow tube  505  so that when sleeve  15  is disposed over hollow tube  505 , sleeve plug  540  will be pulled proximally into distal end  515  of hollow tube  505 , whereby to clamp distal end  17  of sleeve  15  to distal end  515  of hollow tube  505 . Preferably, when hollow tube  505  is pulled proximally, flexible mandrels  545  are also pulled proximally so as to tension flexible mandrels  545 . 
     In a preferred form of the present invention, a second clamp  550  is provided for clamping sleeve  15  to hollow tube  505  adjacent to proximal end  510  of hollow tube  505 , and a third clamp  555  (e.g., a toggle clamp) is provided for clamping sleeve  15  to hollow tube  505  intermediate the length of hollow tube  505 . Preferably, a plurality of spacers  560  are provided along the length of clamping rod  520  for centering clamping rod  520  within hollow tube  505 . 
     If desired, and looking now at  FIG. 41A , an inflation line  562  may be provided for injecting air into proximal end  16  of sleeve  15  so that the air flows in between the sleeve  15  and the outer surface of hollow tube  505 , whereby to facilitate inverting sleeve  15 . 
     Looking now at  FIGS. 42-66 , inversion fixture  500  may be used as follows to invert sleeve  15  and support tubes  50 . 
     Sleeve  15  is passed over hollow tube  505  until proximal end  16  of sleeve  15  is disposed adjacent to second clamp  550  ( FIG. 43 ) and distal end  17  of sleeve is disposed approximately 1 inch beyond distal end  515  of hollow tube  505  ( FIG. 44 ). At this time, sleeve  15  is resting on support block  565  of third clamp  555 , with each of support tubes  50  disposed on either side of sleeve  15 , and with inflation/deflation tube  45  disposed below support tube  50 , in the manner shown in  FIG. 45 . Lever  570  of third clamp  555  is then maneuvered so as to clamp down on sleeve  15  ( FIGS. 46 and 47 ). 
     Flexible mandrels  545  are then passed through support tubes  50  until flexible mandrels  545  extend from distal end  530  of clamping rod  520  to proximal end  525  of clamping rod  520 , where flexible mandrels  545  can be connected to first clamp  535  ( FIGS. 48-51 ). If desired, flexible mandrels  545  may pass through a hole  531  in distal end  530  of clamping rod  520  ( FIG. 50 ). 
     In one preferred form of the invention, and looking now at  FIG. 50A , a flexible mandrel handling fixture  564  may be used to pull flexible mandrels  545  through support tubes  50 . 
     Once flexible mandrels  545  have been passed through support lumens  50 , the operator pulls (i) flexible mandrels  545  proximally to tension flexible mandrels  545 , and (ii) lever  575  of first clamp  535  proximally to move sleeve plug  540  proximally. Flexible mandrels  545  and lever  575  of first clamp  535  are pulled proximally until sleeve plug  540  and distal end  17  of sleeve  15  are pulled into distal end  515  of hollow tube  505 , whereby to clamp distal end  17  of sleeve  15  to distal end  515  of hollow tube  505  ( FIGS. 52-56 ). 
     After distal end  17  of sleeve  15  has been clamped to distal end  515  of hollow tube  505 , lever  570  of third clamp  555  is lifted up to open third clamp  555  and unclamp sleeve  15  from hollow tube  505  ( FIGS. 57 and 58 ). 
     The operator now stands adjacent to the clamped distal end  17  of sleeve  15 , holds onto support tubes  50  and proximally pulls support tubes  50  and sleeve  15  so as to move sleeve  15  distally, i.e., in the direction of arrow  580  ( FIG. 59 ). The operator continues to pull support tubes  50  and sleeve  15  until sleeve  15  has been entirely pulled over, and off of, hollow tube  505 , thereby inverting sleeve  15  ( FIGS. 60 and 61 ). 
     Lever  575  of first clamp  535  is then pushed distally to move sleeve plug  540  distally, whereby to release distal end  17  of sleeve  15  from distal end  515  of hollow tube  505  ( FIGS. 62-65 ). 
     If desired, distal end  17  of sleeve  15  can be trimmed to remove the part of sleeve  15  that was clamped between hollow tube  505  and sleeve plug  540  ( FIG. 66 ). 
     The interior of sleeve  15  can then be coated with a hydrophilic coating and cured with UV light. 
     Reversion Fixture for Reverting Inverted Sleeve  15  and Support Tubes  50   
     Looking now at  FIGS. 67-70 , there is shown a novel reversion fixture  700  for reverting inverted sleeve  15  and support tubes  50  (i.e., the tubes which receive push tubes  30  of sleeve  15 )). 
     Reversion fixture  700  generally comprises a hollow tube  705  having a proximal end  710  and a distal end  715 , and a clamping rod  720  configured to move within hollow tube  705  so that when inverted sleeve  15  is disposed over hollow tube  705 , proximal movement of clamping rod  720  will clamp distal end  17  of inverted sleeve  15  to distal end  715  of hollow tube  705 , as will be discussed in further detail below, so that inverted sleeve  15  can thereafter be pulled distally over hollow tube  705  to revert inverted sleeve  15 . 
     More particularly, clamping rod  720  comprises a proximal end  725  and a distal end  730 , with the proximal end of clamping rod  720  being connected to a first clamp  735  (e.g., a push/pull toggle clamp), and the distal end of clamping rod  720  comprising an expansion plug  740 , which is used in combination with a holding collar  742 , for clamping distal end  17  of inverted sleeve  15  to distal end  715  of hollow tube  705 . More particularly, expansion plug  740  is configured to be expanded, so that when inverted sleeve  15  is disposed over hollow tube  705 , and holding collar  742  is disposed over distal end  17  of inverted sleeve  15 , distal end  17  of inverted sleeve  15  will be clamped between the expanded expansion plug  740  and holding collar  742 , whereby to clamp distal end  17  of inverted sleeve  15  to distal end  730  of clamping rod  720 . Preferably, expansion plug comprises a first portion  743  and a second portion  744 , with flexible mandrels  745  being attached to second portion  744  so that when flexible mandrels  745  are pulled proximally (and/or clamping rod  720  is pulled proximally), second portion  744  is pulled proximally into first portion  743 , thereby expanding the diameter of expansion plug  740 . 
     In a preferred form of the present invention, a second clamp  750  (e.g., a T-slotted framing clamp) is provided for supporting hollow tube  505  adjacent to proximal end  510  of hollow tube  505 , and a support bracket  755  is provided for supporting hollow tube  705  and inverted sleeve  15  intermediate the length of hollow tube  705 . 
     In a preferred form of the present invention, a handle  785  is provided for moving inverted sleeve  15  distally along hollow tube  705 , as will be discussed in further detail below. 
     Looking now at  FIGS. 71-82 , reversion fixture  700  may be used as follows to revert inverted sleeve  15  and support tubes  50 . 
     Inverted sleeve  15  is passed over hollow tube  705  until proximal end  16  of inverted sleeve  15  is disposed adjacent to second clamp  750  and distal end  17  of inverted sleeve is disposed proximal to distal end  730  of clamping rod  720 . At this time, inverted sleeve  15  may be supported by support bracket  755 . 
     Flexible mandrels  745  are then passed through support tubes  50  ( FIG. 72 ) until flexible mandrels  745  extend from distal end  730  of clamping rod  720  to proximal end  16  of the inverted sleeve  15  (with or without using flexible mandrel handling fixture  564  to pull flexible mandrels  545  through support tubes  50 ). If desired, flexible mandrels  745  may pass through a hole  731  in distal end  730  of clamping rod  720  ( FIG. 68 ). 
     Inverted sleeve  15  is now positioned so that distal end  17  of inverted sleeve  15  extends distally of expansion plug  740  and holding collar  742  is placed into position over distal end  17  of inverted sleeve  15  so that holding collar  742  is disposed over inverted sleeve  15  and expansion plug  740  ( FIG. 74 ). 
     The operator now pulls (i) flexible mandrels  745  proximally (and/or clamping rod  720  proximally) to move second portion  744  of expansion plug  740  proximally, whereby to expand expansion plug  740  and create an interference fit between expansion plug  740 , distal end  17  of inverted sleeve  15  and holding collar  742 , thereby clamping distal end  17  of inverted sleeve  15  to clamping rod  720 , and (ii) lever  775  of first clamp  735  proximally ( FIG. 75 ) to move clamping rod proximally until expansion plug  740  and the clamped distal end  17  of sleeve  15  are pulled into distal end  715  of hollow tube  705 . In this way, distal end  17  of inverted sleeve  15  is now clamped to distal end  715  of hollow tube  705 . 
     Handle  785  is now moved proximally over inverted sleeve  15  from distal end  17  of inverted sleeve  15  to proximal end  16  of inverted sleeve  15  ( FIG. 76 ), and proximal end  16  of inverted sleeve  15  is mounted to handle  785  ( FIGS. 77 and 78 ). 
     Once distal end  17  of inverted sleeve  15  has been clamped to distal end  715  of hollow tube  705 , and proximal end  16  of inverted sleeve has been mounted to handle  785 , handle  785  is moved distally along the length of inverted sleeve  15 . Since proximal end  16  of inverted sleeve  15  is connected to handle  785 , distal movement of handle  785  pulls inverted sleeve  15  towards distal end  17  of inverted sleeve  15 , thereby reverting sleeve  15 . 
     Preferably, air may be pumped into handle  785  so that the air flows in between the two layers of sleeve  15  to prevent sleeve  15  from buckling as the sleeve is being reverted, or to straighten sleeve  15  if sleeve  15  has buckled during the reversion process, as shown in  FIG. 79 . 
     Once handle  785  has passed over holding collar  742 , handle  785  can be removed from proximal end  16  of sleeve  15 , and sleeve  15  can be pulled to entirely revert sleeve  15 . 
     After sleeve  15  has been entirely reverted, lever  775  of first clamp  735  is then pushed distally to move second portion  744  of expansion plug  740  distally, whereby to reduce the diameter of expansion plug  740  so that holding collar  742  can be removed from sleeve  15 , thereby releasing distal end  17  of sleeve  15  from distal end  715  of hollow tube  705  ( FIG. 81 ). 
     If desired, distal end  17  of sleeve  15  can be trimmed to remove the part of sleeve  15  that was clamped between expansion plug  740  and holding collar  742  ( FIG. 82 ). 
     Alternative Clamp for Mounting Distal End of Sleeve  15  to Hollow Tube  505   
     As discussed above, novel inversion fixture  500  may be used to invert sleeve  15  and support tubes  50  (i.e., the tubes which receive push tubes  30  of sleeve  15 ) ( FIG. 42 ). To that end, and as discussed above, distal end  530  of clamping rod  520  may comprise a sleeve plug  540  for selectively clamping the distal end of sleeve  15  to hollow tube  505 . With the aforementioned sleeve plug  540 , proximal movement of sleeve plug  540  (i.e., by moving clamping rod  520  proximally), causes sleeve plug  540  to move into distal end  515  of hollow tube  505 , whereby to clamp distal end  17  of sleeve  15  to hollow tube  505  (i.e., by virtue of the interference fit between distal end  17  of sleeve  15  and the inner surface of the sidewall of hollow tube  505 ). 
     However, it should be appreciated that, if desired, an alternative clamping apparatus may be used which can create a more robust clamping of the distal end  17  of sleeve  15  to hollow tube  505 . 
     More particularly, and looking now at  FIGS. 83-96 , there is shown an alternative inversion fixture  500 A having an alternative sleeve plug  540 A which is configured to be moved between a distal position ( FIGS. 84 and 85 ) and a proximal position ( FIGS. 86 and 87 ) to clamp distal end  17  of sleeve  15  to distal end  515  of hollow tube  505 . 
     Sleeve plug  540 A comprises a generally cylindrical side wall  541  formed out of a resilient, flexible material. Sleeve plug  540  is mounted to distal end  530  of clamping rod  520  such that cylindrical side wall  541  extends proximally therefrom and encloses a cavity  542  sized to have a diameter that is slightly smaller than, or generally equal to, the inner diameter of hollow tube  505 . Cylindrical side wall  541  preferably comprises at least two diametrically-opposed slots  543  which permit cylindrical side wall  541  to flex (i.e., contract circumferentially) so as to pass into, and make an interference fit with, the inner surface of distal end  515  of hollow tube  505 . As a result of this construction, and as will hereinafter be discussed in further detail, when a portion (i.e., the distalmost portion) of distal end  17  of sleeve  15  is disposed within cavity  542  of sleeve plug  540 A ( FIGS. 89 and 90 ), sleeve plug  540 A may be selectively moved proximally, whereby to capture a portion (i.e., a portion proximal to the distalmost portion) of distal end  17  of sleeve  15  between the inner surface of hollow tube  505 , and the inner surface of cylindrical side wall  541  of sleeve plug  540 A ( FIG. 91 ). 
     In use, and looking now at  FIGS. 89 and 90 , sleeve  15  is passed over hollow tube  505  until distal end  17  of sleeve  15  extends beyond distal end  515  of hollow tube  505 . Flexible mandrels  545  are then passed through support tubes  50  until flexible mandrels  545  extend from distal end  17  of sleeve  15  to proximal end  16  of sleeve  15  (with or without using flexible mandrel handling fixture  564  to pull flexible mandrels  545  through support tubes  50 ). 
     The operator then feeds the distal ends of flexible mandrels  545 , and distal end  17  of sleeve  15 , into cavity  542  of sleeve plug  540 A until sleeve  15  contacts the distalmost end of cavity  542  of sleeve plug  540 A. If desired, flexible mandrels  545  may be passed through hole  531  ( FIG. 50 ) in distal end  530  of clamping rod  520  in the same manner as with sleeve plug  540  discussed above. 
     Looking now at  FIG. 91 , once flexible mandrels  545  have been passed through hole  531  in distal end  530  of clamping rod  520 , and distal end  17  of sleeve  15  has been disposed within cavity  542  of sleeve plug  540 A, the operator pulls (i) flexible mandrels  545  proximally to tension flexible mandrels  545 , and (ii) lever  575  of first clamp  535  proximally to move sleeve plug  540 A proximally. Flexible mandrels  545  and lever  575  of first clamp  535  are pulled proximally until sleeve plug  540  and distal end  17  of sleeve  15  are pulled into distal end  515  of hollow tube  505 , whereby to clamp distal end  17  of sleeve  15  to distal end  515  of hollow tube  505 . 
     Looking next at  FIGS. 92 and 93 , after distal end  17  of sleeve  15  has been clamped to distal end  515  of hollow tube  505 , the operator stands adjacent to the clamped distal end  17  of sleeve  15 , holds onto support tubes  50  and proximally pulls support tubes  50  and sleeve  15  so as to move sleeve  15  distally, i.e., in the direction of arrow  544 . The operator continues to pull support tube  50  and sleeve  15  until sleeve  15  has been entirely pulled over, and off of, hollow tube  505 , thereby inverting sleeve  15  ( FIG. 94 ). 
     Looking now at  FIG. 95 , lever  575  of first clamp  535  is then pushed distally to move sleeve plug  540 A distally, whereby to release distal end  17  of sleeve  15  from distal end  515  of hollow tube  505 . 
     If desired, distal end  17  of sleeve  15  can be trimmed to remove the part of sleeve  15  that was disposed within cavity  542  of sleeve plug  540 A and the part of sleeve  15  that was clamped between the sidewall of sleeve plug  540 A and the inner surface of the side wall of hollow tube  505 . 
     The interior of sleeve  15  can then be coated with a hydrophilic coating and cured with UV light. 
     While inversion fixture  500 , inversion fixture  500 A and reversion fixture  700  are discussed in connection with inverting and reverting sleeve  15 , it is important to note that inversion fixture  500  and reversion fixture  700  may also be used to invert and revert any multi-lumen sleeve that needs to be inverted and reverted. 
     Furthermore, while the foregoing description discusses applying a hydrophilic coating to the interior surface of sleeve  15 , it is important to note that inversion fixture  500  can be used to invert sleeve  15  in order to apply other types of lubricious coatings (e.g., a liquid such as perfluoropolyether synthetic oil, a powder, etc.) on some or all of its interior surface, so as to facilitate disposition of the sleeve over the endoscope. 
     Modifications 
     While the present invention has been described in terms of certain exemplary preferred embodiments, it will be readily understood and appreciated by those skilled in the art that it is not so limited, and that many additions, deletions and modifications may be made to the preferred embodiments discussed above while remaining within the scope of the present invention.