Abstract:
An endoscopic retractor instrument assembly includes a balloon having a pair of expandable or inflatable end portions and at least one expandable or inflatable spacer portion connecting the end portions to one another. A fastener is provided for securing the balloon to a distal end of an endoscopic insertion member, with the balloon being disposed in a collapsed configuration along an outer surface of the endoscopic insertion member. An inflation element is operatively coupled with the balloon for enabling an inflating of the balloon from the collapsed configuration to an expanded use configuration in which the spacer portion pushes the end portions apart from one another and in which the balloon extends at least partially in a distal direction away from the distal end of the endoscopic insertion member for spreading internal tissues of a patient to facilitate access to the tissues via the endoscopic insertion member.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to a medical device and to an associated medical technique. More particularly, this invention relates to an endoscopic instrument and to an endoscopic method.  
           [0002]    Flexible endoscopes are inserted into the digestive tract for diagnostic and therapeutic purposes. Endoscopes generally include a light guide for transmitting optical-wavelength electromagnetic radiation into the patient. Images are captured, typically via lenses and an optical fiber bundle or a charge-coupled device, whereby a user can visually inspect the inner walls or surfaces of the digestive tract. One common objective of endoscopic investigations in the digestive tract is to detect the presence of polyps. Where a polyp is visually detected, particularly in the colon, it should be severed, captured, and removed from the patient. Alternatively, particularly where the polyp may be a malignant cancer, the polyp may be severed and captured for extraction from the patient.  
           [0003]    One problem frequently encountered by endoscopists is that folds of tissues in the digestive tract and particularly the colon can obscure polyps so that they can be overlooked. The colon is often collapsed and may be partially or completely draped over a lesion. In order to distend the walls of the colon, the endoscopist often pumps air into the organ. However, if too much air is introduced, the colon could perforate. Also, the patient is made quite uncomfortable with introduction of substantial amounts of air.  
           [0004]    Another problem with visualization during an endoscopic procedure is that polyps sometimes bleed when they are severed. If the lesion site cannot be adequately visualized, it is difficult to contain and control the bleeding.  
           [0005]    Further problems in performing endoscopy include the time it takes to reprocess the endoscope between procedures, the potential for transmission of infection from one patient to another because of remaining bioburden inside or on the endoscope, and the added cost to the endoscopy units because of the time spent in manual cleaning of the endoscopes.  
         OBJECTS OF THE INVENTION  
         [0006]    It is a general object of the present invention to provide a retractor instrument utilizable in surgical and/or diagnostic procedures.  
           [0007]    A more specific object of the present invention is to provide such an instrument assembly which is utilizable in endoscopic procedures.  
           [0008]    A further object of the present invention is to provide such an instrument assembly which is inexpensive and/or easy to use.  
           [0009]    It is an even more specific object of the present invention to provide an endoscopic instrument assembly which is particularly suitable for use with flexible endoscopes during investigations of the digestive or gastro-intestinal tract or other internal body cavities.  
           [0010]    It is another object of the present invention to provide an endoscopic procedure for facilitating visual inspection of the digestive tract.  
           [0011]    An additional object of the present invention is to provide an instrument and/or method for use with flexible endoscopes, which reduces patient discomfort and risk by potentially reducing the amount of air introduced into the gastrointestinal tract.  
           [0012]    A further objective is to minimize the amount of time it takes to reprocess an endoscope between successive procedures.  
           [0013]    Another objective is to avoid transmission of infection from one procedure to the next owing to the convoluted and intricate shape of the endoscope that allows bioburden to remain lodged in or on the endoscope.  
           [0014]    It is yet another object of the present invention to provide an endoscopic instrument that is disposable.  
           [0015]    These and other objects of the invention will be apparent from the drawings and descriptions herein. Although every object of the invention is attained by at least one embodiment of the invention, there is not necessarily any one embodiment that achieves all of the objects of the invention.  
         SUMMARY OF THE INVENTION  
         [0016]    An endoscopic retractor instrument assembly comprises, in accordance with the present invention, a balloon having at least one expandable or inflatable end portion and at least one expandable or inflatable spacer portion connected to the end portion. A fastener component is provided for securing the balloon to a distal end of an endoscopic insertion member, with the balloon being disposed in a collapsed configuration along an outer surface of the endoscopic insertion member. An inflation element is operatively coupled with the balloon for enabling an inflating of the balloon from the collapsed configuration to an expanded use configuration in which the spacer portion pushes the end portion in a distal direction away from the distal end of the endoscopic insertion member for spreading internal tissues of a patient to facilitate access to the tissues via the endoscopic insertion member.  
           [0017]    Pursuant to another feature of the present invention, the balloon is a unitary single-piece balloon preformed so that the expanded configuration includes the end portion and the spacer portion. The balloon is preferably formed from an elongate tubular preform by bending and winding the preform to form the balloon so that the balloon has a singular flow path for the introduction of a pressurizing fluid.  
           [0018]    The fastener may include a sheath disposable about the endoscopic insertion member and/or an end cap attached over a distal tip of the endoscopic insertion member. Preferably, the sheath includes at least one adhesive strip for detachably securing the sheath to the insertion member. The sheath preferably includes a tear string for severing the sheath to facilitate removal thereof from the insertion member. The tear string is preferably disposed along a weakened area of the sheath to facilitate the severing of the sheath and the separation of the tear string from the sheath  
           [0019]    The end portion of the balloon may take the form of a coil. At an end opposite the coil, the balloon may include an end portion in the form of a coil or a C-shaped segment.  
           [0020]    A medical method comprises, in accordance with the present invention, providing an endoscopic insertion member, providing an endoscopic retractor instrument including a balloon, and securing the retractor instrument to a distal end portion of the insertion member so that the balloon is disposed in a collapsed configuration along an outer surface of the insertion member. Further steps of the method include inserting the distal end portion of the insertion member together with the collapsed balloon into a patient, and thereupon inflating the balloon to form an enlarged or expanded configuration extending at least partially in a distal direction away from the distal end portion of the insertion member. The enlarged or expanded configuration of the balloon is used to spread internal tissues of the patient in a region located distally of the insertion member.  
           [0021]    Where the balloon has an expandable or inflatable end portion and at least one expandable or inflatable spacer portion connecting the end portion to the endoscopic insertion member, the inflating of the balloon includes inflating the spacer portion to separate the end portion from the endoscopic insertion member and inflating the end portion to engage the tissues.  
           [0022]    Where the enlarged or expanded configuration of the balloon defines at least one opening, the method further comprises directly accessing the tissues from the distal end portion of the insertion member via the opening.  
           [0023]    The securing of the balloon to the insertion member preferably includes attaching a sheath and an end cap to the insertion member, the balloon being attached to at least one of the sheath and the end cap. The sheath is preferably attached to the insertion member by adhesively coupling the sheath to the insertion member. At least one protective strip is removed from an adhesive region on the sheath and then the exposed adhesive region is placed into contact with an outer surface of the sheath or the endoscope insertion member and pressed against the insertion member to form an adhesive bond.  
           [0024]    At the termination of the procedure, the insertion member is removed from the patient, together with the sheath and the balloon. Then a tear string is pulled along at least a portion of the sheath to sever the sheath, which is subsequently separated from the insertion member.  
           [0025]    An endoscopic retractor instrument comprises a plurality of parts movably connected to one another, means for disposing the parts in a collapsed or reduced-size configuration at a distal end portion of an insertion member of an endoscope, and an actuator such as a pressurization tube operatively connected to the parts for enabling a movement of the parts relative to one another so that the parts assume an enlarged or expanded configuration extending at least partially in a distal direction away from the distal end portion of the insertion member for spreading internal tissues of a patient- to facilitate access to the tissues via the insertion member. The means for disposing the parts preferably includes means such as an endoscope sheath and an endoscope end cap for removably attaching the parts to an outer surface of the insertion member.  
           [0026]    The parts preferably include a plurality of expandable or inflatable balloon parts that are differently shaped parts of a single tubular balloon member. The balloon member is preformed to assume an expanded configuration having the differently shaped parts.  
           [0027]    Pursuant to a particular embodiment of the method, the inflating of the balloon or bladder includes expanding the end portions so that one or both assumes the form of a coil, the spacer portion being one of a plurality of elongate expandable or inflatable spacer parts each having one end connected to and communicating with one of the end portions and an opposite end connected to and communicating with another one of the end portions. More generally stated, the enlarged or expanded configuration of the balloon or bladder may be at least partially a spiral configuration, the inflating of the balloon or bladder including the forming of the balloon or bladder at least partially into the spiral configuration.  
           [0028]    In this method, the securing of the balloon or bladder to the insertion member may include attaching a sheath and an end cap to the insertion member, the balloon or bladder being attached to at least one of the sheath and the end cap.  
           [0029]    As discussed above, the retractor balloon is preferably manufactured from a single elongate preform which is differentially bent and provided with a “memory” to form the end portions and spacer portions.  
           [0030]    A sheath used to attach a balloon-type retractor to an endoscopic insertion member may take the form of a web or sheet, which is wrapped about at least a distal end portion of the insertion member, adhesively fastened about the insertion member, and inserted with the insertion member into a patient. Subsequently the insertion member with the sheath wrapped thereabout is removed from the patient. If a tear string is embedded in the sheath, the tear string is pulled to sever the sheath along a predetermined line where the sheath is weakened, e.g., via a score line or a reduced thickness. Subsequently the insertion member and the torn or severed sheath are separated from one another.  
           [0031]    The wrapping of the sheath preferably includes providing a cradle member having a groove, placing the web or sheet over the cradle member so that a portion of the web or sheet lies in the groove, disposing the endoscopic insertion member on the portion of the web or sheet lying in the groove, and winding a side portion of the web or sheet about the endoscopic insertion member after the disposing thereof on the web or sheet. This technique facilitates application of the sheath in that the endoscopic insertion member is partially surrounded by the sheath in the cradle member and the operator or user need only fold the longitudinal edge portions over one another and press the adhesive regions to effectuate an effectively secure closure.  
           [0032]    The fastening of the sheath to the endoscopic insertion member preferably includes adhesively securing a first longitudinal edge region of the web or sheet to an outer surface of the endoscopic insertion member, and subsequently adhesively securing a second longitudinal edge region of the web or sheet to on outer surface of the web or sheet.  
           [0033]    As discussed above, an endoscopic retractor in the shape of a balloon may be attached in a collapsed configuration to the insertion member along an outer side thereof via either the sheath or an end cap or both. After the inserting of the insertion member and the sheath into the patient, the balloon is inflated to assume an enlarged or expanded configuration extending at least partially in a distal direction away from the insertion member. The enlarged or expanded configuration of the balloon is used to spread internal tissues of the patient to facilitate at least a visual access to the tissues. This operation is typically done during a withdrawal of the endoscopic insertion member from the patient.  
           [0034]    Naturally, a retractor balloon or bladder in accordance with the invention expands radially or transversely, as well as longitudinally or axially. The transverse expansion of the instrument enables the application of pressure to the colon wall or other portion of a digestive tract or internal body tissues to separate the tissues and smooth out folds. This facilitates inspection and the performance of endoscopic operations on target tissues inside the patient.  
           [0035]    The inflation element of a retractor instrument assembly in accordance with the present invention may include a feed tube or conduit connected to the balloon or bladder for enabling the delivery of a pressurizing fluid such as saline solution or a gas (air) to the balloon or bladder. This inflation tube is typically a flexible line extending back along an endoscopic insertion member to a pressurization device (e.g., a syringe) outside of the patient. The inflation tube may extend through the biopsy channel of an endoscope or, where a sheath is provided as discussed above, may extend through, or be incorporated as, a channel in the sheath.  
           [0036]    The inflation element of a balloon-type retractor instrument assembly may include a one-way valve disposed between the inflation tube and the balloon or bladder. The valve automatically prevents the escape of the pressurizing fluid from the balloon or bladder and thus facilitates the use of the instrument in an endoscopic procedure. The valve may be disposed inside the balloon or bladder or alternatively in a nipple or nub element connected thereto. Where the inflation tube extends through a biopsy channel in an endoscope insertion member or endoscope sheath, the tube may be removably connected to the balloon or nipple, for instance, via a screw connection or a frangible link. The extraction of the inflation tube upon the disconnection thereof from the balloon clears the site of interest and thereby facilitates the performance of additional diagnostic or therapeutic procedures via the biopsy channel. This removal is not necessary where a sheath having multiple channels is used.  
           [0037]    The present invention enables the insertion of a retractor deep inside a patient through a natural body opening. At the site of interest, whether a diagnostic or surgical site, the retractor is expanded to a configuration many times larger than the collapsed insertion configuration, thereby enabling a substantial spreading of internal tissues.  
           [0038]    In a balloon-type retractor as disclosed herein, windows or openings are provided which allow direct access to the internal tissues of the patient from the distal end of an endoscopic insertion member. Upon expansion, the retractor provides transverse pressure on the wall of the gastrointestinal tract and expands the organ and smoothens the folds, allowing for the viewing and potential diagnostic and/or interventional activity. The windows or openings defined by the expanded retractor allow for an instrument such as a snare cautery device to capture a polyp. The openings are not so large, however, that the retraction process is impaired.  
           [0039]    The inner diameter of a retractor pursuant to the present invention is preferably large enough to allow the operator to comfortably operate on a polyp or other lesion. The outer diameter of the device is sized correctly to support the colon walls in an open position but is not so large as to cause colonic perforation. The balloon diameter is large enough to allow support of the colon wall, but small enough as to not obstruct the visibility of the colon being retracted.  
           [0040]    A retractor balloon as disclosed herein is made of a rubber or elastic polymeric material with limited expandability so that it will not be overextended, and burst. The collapsed configuration of the device after its use is flexible enough to permit extraction of the device from the colon or other hollow organ or reintroduction of the device into a sheath with which it was introduced.  
           [0041]    Where a retractor balloon is attached to the distal end of an endoscope, as discussed above, the proximal end of the balloon may be configured to fit snugly, or with a clamping or securing attachment, over the outside of the distal end of the endoscope in a deflated configuration. The distal end of the balloon is configured so as not to interfere with insertion of the endoscope or visualization through the endoscope. Thus, the collapsed balloon is situated outside the field of visualization surrounding the endoscope lens, either in the same transverse plane as the lens or proximal to it. The endoscope with the attached retractor in a collapsed configuration is inserted into a hollow organ, e.g., the colon, to the most proximal end (farthest inside the patient) of the hollow organ as determined by the endoscopist. The balloon is then inflated using the inflation element at the proximal end of the insertion tubing. The distal portion of the balloon unfolds during this process and moves distal to the distal end of the endoscope, the proximal portion of the balloon inflates around the endoscope and may further secure the device to the endoscope. The spacer members secure the two balloon ends at a predetermined distance from one another. The endoscopist then slowly retracts the endoscope with the enlarged or expanded retractor and views the GI tract between the two ends of the retractor as the retractor places pressure on and expands or stretches the wall of the GI tract, minimizing tissue folds that can interfere with viewing of the organ. The spacing (windows, openings) between the ends of the balloon allow for diagnostic and interventional procedures by the endoscopist. In other words, as the endoscope is pulled back, the physician performs his or her examination, and the colon collapses behind the enlarged or expanded retractor, which provides a telescoped part of the colon in front of (distal to) the lens that is now distended to its full inner diameter, allowing for visualization of polyps or other pathology behind every fold and 360 degrees around the wall of the colon. When a polyp happens to come into view, the withdrawal procedure is interrupted, the telescope (retractor) is situated framing the polyp, and removal of the polyp takes place. Then, the polyp is captured and with the retractor still in place the withdrawal continues and the rest of the colon or other hollow organ is visualized.  
           [0042]    Where a sheath is used as an attachment device for an endoscopic retractor, in accordance with the invention, the sheath provides the additional benefit of keeping the endoscope relatively free from contact with the patient&#39;s body fluids or fecal material. The sheath is made of a thin flexible material that is split from its proximal end to the distal end or to a point close to the distal end. One side of the split line has a permanent adhesive component that sufficiently overlaps the other side of the sheath to enable fixation of the sheath to an endoscope insertion member. The adhesive can be covered by a removable protective strip that is simply peeled off to expose the adhesive layer. The sheath is then wrapped over the endoscope and adhered to the non-adhesive side of the sheath, making a secure and fluid tight bond the entire length of the sheath. In order to easily apply a long and narrow sheath in accordance with the invention to an endoscope, the non-adhesive part of the sheath is first lightly bonded to the insertion shaft of the endoscope by means of a light-adhesive region also covered by a removable protective strip. Only once the first side is lightly bonded to the endoscope is the strip overlying the permanent glue remove. That side is then folded over the first side and permanently attached as described above. The sheath also contains an embedded tear-strip with a small portion of the tear-strip exposed, e.g., at the proximal end of the sheath, so as to facilitate grabbing of the tear strip and pulling it lengthwise down the sheath causing the sheath to easily split and be safely, cleanly and easily removed from the endoscope.  
           [0043]    The distal end of the sheath is provided or associated with an end cap in the shape of a short tube that incorporates a transparent end portion that fits over the distal end of the endoscope insertion shaft, allowing for use of the endoscope&#39;s visualization capabilities and potentially the working channels of the endoscope.  
           [0044]    A retractor balloon as discussed above may be permanently attached to the sheath, or may be separate from the sheath and attached to it only prior to an endoscopic procedure. Thus the sheath would be attached first to enclose the shaft of the endoscope, and then the retractor is placed upon the distal part of the sheath substantially proximal to the lens as not to interfere with visualization. The attachment can be by glue or other means.  
           [0045]    The sheath may include built-in or insertable biopsy, suction and irrigation channels or any combination thereof or may include space along the length of the sheath to allow addition of said channels which may be comprised of substantially similar tubing as the insertion tubing of the aforementioned devices. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0046]    [0046]FIGS. 1A-1H are schematic cross-sectional views of a human colon, showing successive steps in the performance of an endoscopic polypectomy using an endoscopic insertion shaft provided at a distal end with a balloon-type endoscopic, in accordance with the present invention.  
         [0047]    [0047]FIGS. 2A-2H are schematic cross-sectional views similar to FIGS. 1A-1H, showing successive steps in the performance of an endoscopic polypectomy using an endoscopic insertion shaft provided at a distal end with an alternative balloon-type endoscopic retractor, in accordance with the present invention.  
         [0048]    [0048]FIG. 3 is a schematic exploded isometric view of an endoscopic sheath assembly utilizable in the procedures of FIGS. 1A-1H and  2 A- 2 H, in accordance with the present invention.  
         [0049]    [0049]FIGS. 4A-4D are schematic isometric views of an endoscopic insertion shaft and the sheath assembly of FIG. 3, showing successive steps in the application of the sheath assembly to the endoscope insertion shaft.  
         [0050]    [0050]FIG. 5 is a detail schematic isometric view of a portion V of the sheath of FIG. 4A, on a larger scale.  
         [0051]    [0051]FIG. 6 is a schematic isometric view of a support for an endoscope insertion member, to aid in the application process of FIGS. 4A-4D.  
         [0052]    [0052]FIG. 7 is a schematic isometric view, of a modified endoscopic sheath assembly in accordance with the present invention, showing a step in the application of the sheath assembly to an endoscope insertion shaft.  
         [0053]    [0053]FIG. 8 is a detail view, on a larger scale, of a distal end of the sheath assembly of FIG. 7.  
         [0054]    [0054]FIG. 9 is a schematic end elevational view, on an even larger scale, of the sheath assembly of FIG. 7.  
         [0055]    [0055]FIG. 10 is a schematic isometric view of a sheath assembly in accordance with the present invention on an endoscope insertion shaft, showing a stage in the removal of the sheath assembly from the endoscope insertion shaft.  
         [0056]    [0056]FIGS. 11A-11H are schematic cross-sectional views similar to FIGS. 1A-1H and  2 A- 2 H, showing successive steps in the performance of an endoscopic polypectomy using an endoscopic insertion shaft provided at a distal end with another balloon-type endoscopic retractor, in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0057]    [0057]FIG. 1A shows an endoscope insertion member or shaft  104  encased in a sheath assembly  106  that carries, at a distal end, a balloon-type retractor  108  in a collapsed configuration. Retractor balloon  108  is essentially identical to that disclosed above with reference to FIGS. 1 and 2 and is connected to an inflation tube  110  extending longitudinally back along endoscope insertion member  104 . Tube  110  may be a part of or connected to a sheath  112  of assembly  106 . Alternatively, tube  110  may extend separately alongside sheath  112  and endoscope insertion member  104 . In another alternative, tube  110  extends through a biopsy channel of endoscope insertion member  104 .  
         [0058]    It is to be noted that retractor balloon  108  is configured in its collapsed insertion configuration so as not to interfere with insertion of the endoscope member  104  or visualization through the endoscope. Thus, the collapsed retractor balloon  108  is situated outside the visual field of the endoscope lens (not shown), and is disposed either in the same transverse plane as the lens or proximal to it.  
         [0059]    In the collapsed configuration, retractor balloon  108  is inserted together with a distal end portion of insertion member  104  into a hollow organ such as a colon CLN, as illustrated in FIG. 1A. FIG. 1A depicts the distal end portion of insertion member  104 , sheath  112 , and retractor balloon  108  being pushed through an ascending segment  114  of colon CLN, as indicated by an arrow  116 . As shown in FIG. 1B, sheath assembly  106  includes an end cap  118  in addition to sheath  112 . FIG. 1B shows insertion member  104 , sheath assembly  106 , and retractor balloon  108  moving along a horizontal segment  120  of the colon CLN (arrow  122 ). In FIG. 1C, the distal end portion of the endoscope insertion member  104  has reached the upstream terminus  124  of the colon CLN. At this juncture, a pressurizing fluid such as a saline solution is fed through tube  110  (FIG. 1A) to inflate retractor balloon  108  from the collapsed insertion configuration of FIGS. 1A and 8B. During the inflation process, the distal portion of retractor balloon  108  unfolds and moves distal to the distal end of the endoscope insertion member  104 . The proximal portion of the retractor balloon  108  may be designed to inflate around the endoscope to further secure the retractor balloon to the endoscope.  
         [0060]    [0060]FIG. 1C shows retractor balloon  108  in a partially enlarged or expanded configuration. Tubules  126 , which communicate with tube  110 , extend from sheath end cap  118  to a proximal toroidal end portion  128  of retractor balloon  108 . End portion  128  is connected to a distal toroidal end portion  130  via a plurality of elongate axially extending spacer tubes  132 . The spacer tubes  132  secure the two balloon end portions  128  and  130  at a predetermined distance from one another. Pressurizing fluid is conveyed through tubules  126 , end portion  128 , and tubes  132  to end portion  130 .  
         [0061]    Once retractor balloon  108  has been inflated to a fully expanded configuration shown in FIG. 1D, the endoscope insertion member  104  is slowly pulled in a proximal direction out of the patient, as indicated by an arrow  134 . During the withdrawal, the endoscopist views the wall of colon CLN through a window or opening (not separately labeled) defined by end portions  128  and  130  of retractor balloon  108 . As it is pulled through colon CLN, the inflated retractor balloon  108  places pressure on and expands or stretches the wall of the colon, reducing or eliminating tissue folds that can interfere with viewing of the organ. The spacing (windows, openings) between end portions  128  and  130  allow for diagnostic and interventional procedures by the endoscopist. When a polyp PLP happens to come into view (FIG. 1F), the withdrawal procedure is interrupted with the retractor balloon  108  framing the polyp. Removal of the polyp PLP can then bee effectuated via a cauterization snare operation (not shown). The polyp PLP is captured and with the retractor  108  still in place the withdrawal may continue so that the remaining segment of the colon CLN or other hollow organ may be visualized.  
         [0062]    [0062]FIG. 1G depicts retractor balloon  108  in a state of partial deflation after an investigation has been completed. FIG. 1H depicts retractor balloon  108  in a state of mostly completed deflation during a withdrawal of endoscope insertion member  104 . As discussed above with reference to FIGS. 1 and 2, an endoscopic scalpel or other sharp instrument may be inserted through the biopsy channel of the endoscope insertion member  104  and used to perforate the retractor balloon, thereby allowing depressurization thereof. Alternatively, if the retractor balloon communicates with tube  110  via a two-way valve, then depressurization may be accomplished by applying suction from the proximal end of the tube. In that case, tube  110  must have a transverse rigidity preventing collapse thereof in the presence of suction forces.  
         [0063]    [0063]FIG. 2A shows an endoscope insertion member or shaft  144  encased in a sheath assembly  146  that carries, at a distal end, a balloon-type retractor  148  in a collapsed configuration. Retractor balloon  148 , at least in an expanded configuration (FIGS. 2D, 9E), takes the form of a spiral or helix. Retractor balloon  148  is connected to an inflation tube (not shown) extending longitudinally back along endoscope insertion member  144 . As discussed above with reference to FIG. 1A, that tube may be a part of or connected to a sheath  152  of assembly  146 . Alternatively, the inflation tube may extend separately alongside sheath  152  and endoscope insertion member  144 . In another alternative, the inflation tube extends through a biopsy channel of endoscope insertion member  144 .  
         [0064]    It is to be noted that retractor balloon  148  is configured in its collapsed insertion configuration so as not to interfere with insertion of the endoscope member  144  or visualization through the endoscope. Thus, the collapsed retractor balloon  148  is situated outside the visual field of the endoscope lens (not shown), and is disposed either in the same transverse plane as the lens or proximal to it.  
         [0065]    In the collapsed configuration, retractor balloon  148  is inserted together with a distal end portion of insertion member  144  into a hollow organ such as a colon CLN′, as illustrated in FIG. 2A. The distal end portion of insertion member  144 , together with sheath  152  and retractor balloon  148  are pushed first through an ascending segment  154  of colon CLN′, as indicated by an arrow  156 , and then through a horizontal segment  158 , as indicated by an arrow  160  in FIG. 2B.  
         [0066]    Sheath assembly  146  includes an end cap  162  in addition to sheath  152 , as shown in FIGS. 2B and 2C. Once the distal tip of the endoscope insertion member  144  has reached a beginning terminus  164  of the colon CLN′, as shown in FIG. 2C, a pressurizing fluid such as a saline solution is fed to retractor balloon  148  to expand the same from the collapsed insertion configuration of FIGS. 2A and 2B. During the inflation process, a distal portion of retractor balloon  148  unfolds and moves distal to the distal end of the endoscope insertion member  144 , as shown in FIG. 2C. A proximal portion of the retractor balloon  148  may be designed to inflate around the endoscope to further secure the retractor balloon to the endoscope.  
         [0067]    [0067]FIG. 2C shows retractor balloon  148  in a partially enlarged or expanded configuration. Tubules  166 , which communicate at one side with the inflation tube, extend from sheath end cap  162  to a proximal end portion  168  of retractor balloon  148 . End portion  168  communicates with a distal end portion  170  via a spiral central portion  172  and via a plurality of elongate axially extending spacer tubes  174 . The spacer tubes  174  serve in part to secure the two balloon end portions  168  and  170  at a predetermined distance from one another. Pressurizing fluid is conveyed through tubules  166 , end portion  168 , and tubes  174  to end portion  170 .  
         [0068]    Once retractor balloon  148  has been inflated to a fully expanded configuration shown in FIG. 2D, the endoscope insertion member  144  is slowly pulled in a proximal direction out of the patient, as indicated by an arrow  176  (FIG. 2E). During the withdrawal, the endoscopist views the wall of colon CLN′ through a window or opening (not separately labeled) defined by end portions  168  and  170  of retractor balloon  148 . As it is pulled through colon CLN′, the inflated retractor balloon  148  places pressure on and expands or stretches the wall of the colon, reducing or eliminating tissue folds that can interfere with viewing of the organ. The spacing (windows, openings) between end portions  168  and  170  allow for diagnostic and interventional procedures by the endoscopist. When a polyp PLP′ happens to come into view (FIG. 2F), the withdrawal procedure is interrupted with the retractor balloon  148  framing the polyp. Removal of the polyp PLP can then bee effectuated via a cauterization snare operation (not shown). The polyp PLP′ is captured and with the retractor  148  still in place the withdrawal may continue so that the remaining segment of the colon CLN′ or other hollow organ may be visualized.  
         [0069]    [0069]FIG. 2G depicts retractor balloon  148  in a state of partial deflation after an investigation has been completed. FIG. 2H depicts retractor balloon  148  in a state of mostly completed deflation during a withdrawal of endoscope insertion member  144 . As discussed above with reference to FIGS. 1G and 1H, an endoscopic scalpel or other sharp instrument may be inserted through the biopsy channel of the endoscope insertion member  144  and used to perforate the retractor balloon, thereby allowing depressurization thereof. Alternatively, if the feed channel extending to tubules  166  is provided with a two-way valve and no one-way valve, then depressurization may be accomplished by applying suction from the proximal end of the tube.  
         [0070]    Sheath assembly  106  or  146  may take the form shown in FIG. 3 et seq. As depicted in FIG. 3, an endoscopic sheath assembly  178  includes an endoscope sheath  180  in the form of a web member or sheet and further includes an endoscope end cap  182 . Sheath  180  is provided with a layer of adhesive material  184 ,  186 ,  188  along a forward end region, a first longitudinal edge region and a second longitudinal edge region, respectively (not separately enumerated). Sheath  180  is further provided along a weakened (e.g., thinned or scored) region (not separately labeled) with an embedded tensile member  190  such as a tear string for enabling a severing of the sheath in preparation for removal of the sheath from an endoscope insertion member  192  (FIG. 4A). Releasable protective cover strips  194 ,  196 ,  198  are removably attached to the adhesive layers or regions  184 ,  186 ,  188 . Preferably, the adhesive material of layers or regions  184  and  186  is a permanent adhesive, while the adhesive material of layer or region  188  forms a separable or releasable bond.  
         [0071]    In applying endoscopic sheath assembly  178  to endoscope insertion member  192  (FIG. 4A), end cap  182  is first placed over a distal tip  200  of the insertion member. End cap  182  includes a substantially rigid collar  202  and a transparent plate  204 . End plate  204  transmits illumination into a patient from a light outlet  206  on endoscope tip  200 . Returning light passes through plate  204  and impinges on a lens  208 .  
         [0072]    After the placement of end cap  182  over distal tip  200  of insertion member  192 , protective cover strip  198  is peeled away from longitudinal adhesive layer  188 . In addition, protective cover strip  194  (see FIG. 5) is removed from adhesive layer  184 . Adhesive layer  188  is aligned longitudinally with endoscope insertion member  192  with the latter in a straight configuration, parallel to an axis thereof. Adhesive layer  188  is pressed against insertion member  192 . Then the distal end of sheath or web member  180  is wrapped around collar  202 , as shown in FIG. 4B, so that adhesive layer  184  permanently bonds to end cap  182 . Prior to completing the wrapping of the distal end of sheath or web member  180  about collar  202 , protective cover strip  196  is peeled away from longitudinal adhesive layer  186  (see FIG. 5). The uncovered layer  186  of permanent adhesive is then placed into an overlapping configuration with the sheath or web  180  and bonded thereto (FIG. 4C) so that the sheath surround the endoscope insertion member  192  in tight fluid-sealed fit (FIG. 4D).  
         [0073]    An alternative method of applying sheath assembly  178  to endoscope insertion member  192  utilizes a support cradle  210  shown in FIG. 6. Support cradle  210  has a groove  212  of equivalent diameter to insertion member  192 . First sheath or web member  180  with at least protective cover strip  194  removed is laid into groove  212 . Endoscope insertion member  192  with end cap  182  positioned thereon is then placed atop sheath  180  so that collar  202  engages exposed adhesive layer  184 . At this time, protective cover strip  198  may be removed to expose adhesive layer  188  which is then pressed along insertion member  192 . Subsequently, strip  196  is removed to expose permanent-adhesive layer  186  which is then bonded to an outer surface of the sheath or web  180 .  
         [0074]    In an alternative sheath assembly  214  shown in FIG. 7, a sheath or web member  216  is attached to an end cap  218  during manufacture. Sheath or web  216  is provided along part of a first longitudinal edge with a layer  220  of lightly bonding adhesive covered by a releasable protective strip  222 . Sheath or web  216  is provided along part of a second or opposing longitudinal edge with a layer  224  of permanently bonding adhesive covered by a releasable protective strip  226 . A tear string  228  is embedded in sheath or web  216  and extends longitudinally therealong. Along a distal end portion of sheath assembly  214 , the opposing longitudinal edge regions of the sheath or web  216  overlap and are bonded to one another, prior to introduction of an endoscope insertion member  230  into the sheath assembly, as shown in FIGS. 7 and 9.  
         [0075]    [0075]FIG. 10 depicts an initial step in the removal of a sheath assembly  106 ,  146 ,  178 ,  214  from an endoscope insertion member (not separately labeled). A tear string  190 ,  228  is manually grasped and pulled to sever or rip the respective sheath  112 ,  152 ,  180 ,  216  along a straight or curved line extending at least a substantial portion of the length of the endoscope insertion member. The rip or tear in the sheath  112 ,  152 ,  180 ,  216  is preferably formed in a direction from the proximal end to the distal end of the instrument.  
         [0076]    [0076]FIG. 11A shows an endoscope insertion member or shaft  232  encased in a sheath assembly  234  that carries, at a distal end, a balloon-type retractor  236  in a collapsed configuration. Retractor balloon  236  is essentially a single tubular member that is preformed to assume a fully enlarged or expanded configuration in a tapered or frustoconical form as shown in FIGS. 11E and 11F. So configured, retractor balloon  236  has a C-shaped proximal end portion  238  that is bonded to sheath assembly  234  about a distal circumference thereof. Retractor balloon  236  further includes a coiled distal end portion  240  connected to C-shaped proximal end portion  236  via three circumferentially spaced struts or spacer members  242 ,  244 ,  246 . The single tubular member that is the retractor balloon  236  has strut or spacer member  242  as an initial segment unitary or continuous at one end with the coiled distal end portion  240 . Distal end portion  240 , which has approximately one-and-half turns or windings (not separately designated), is in turn integral and continuous with strut or spacer member  244 . At an end opposite coiled distal end portion  240 , strut or spacer member  244  is unitary and continuous with one end of C-shaped proximal end portion  238 . C-shaped proximal end portion  238  in turn leads directly into strut or spacer member  246 , which is bonded, e.g., glued, to coiled distal end portion  240 . Strut or spacer member  246  may be glued over an aperture (not shown) provided in coiled distal end portion  240 . Similarly, strut or spacer member  242  is bonded to C-shaped proximal end portion  238  preferably over an aperture therein to facilitate the passage of pressurizing fluid to inflate retractor balloon from the collapsed insertion configuration of FIGS. 11A and 11B to the expanded use configuration of FIGS. 11D-11F.  
         [0077]    Retractor balloon  236  is expanded from the collapsed configuration of FIGS. 11A and 11B after the distal end of the endoscope insertion member  232  reaches the upstream end  252  of the colon shown in FIG. 11C. FIG. 11C shows retractor balloon  236  in partially expanded configuration. Retractor balloon  236  is expanded by means of an inflation or pressurization tube  248  (FIG. 11A) in the form of a catheter extending longitudinally back along endoscope insertion member  232 . Tube  248  may be a part of or connected to a sheath  250  of assembly  234  or may extend loosely alongside sheath  250  and endoscope insertion member  232 . Alternatively, an inflation tube  254  may extend through a biopsy channel  256  of endoscope insertion member  232 . FIGS. 11D-11H show inflation tube  248  connected to an inlet end of spacer member  242  via a valve or port element  249 . Preferably, tube  248  extends longitudinally along the endoscope insertion member  232  and is substantially collinear with spacer member  242 . However, as illustrated in FIGS. 11D-11H, inflation tube  248  and spacer member  242  may be angularly offset about the endoscope insertion member  232 .  
         [0078]    It is to be noted that retractor balloon  236  is configured in its collapsed insertion configuration so as not to interfere with insertion of the endoscope member  232  or visualization through the endoscope. Thus, the collapsed retractor balloon  236  is situated outside the visual field of the endoscope lens (not shown), and is disposed either in the same transverse plane as the lens or proximal to it.  
         [0079]    In the collapsed configuration, retractor balloon  236  is inserted together with a distal end portion of insertion member  232  into a hollow organ such as a colon CLN″, as illustrated in FIG. 11A. FIG. 11A depicts the distal end portion of insertion member  232 , sheath  250 , and retractor balloon  236  being pushed through an ascending segment  258  of colon CLN, as indicated by an arrow  260 . As shown in FIG. 11B, sheath assembly  234  may include an end cap  262  in addition to sheath  250 . FIG. 11B shows insertion member  232 , sheath assembly  234 , and retractor balloon  236  moving along a horizontal segment  264  of the colon CLN″ (arrow  266 ). In FIG. 11C, the distal end portion of the endoscope insertion member  232  has reached the upstream end  252  of the colon CLN″. At this juncture, a pressurizing fluid such as a saline solution is fed through tube  248  (FIG. 11A) to inflate retractor balloon  236  from the collapsed insertion configuration of FIGS. 11A and 11B. During the inflation process, the coiled distal end portion  240  of retractor balloon  236  unfolds and moves distal to the distal end of the endoscope insertion member  232 . The C-shaped proximal end portion  238  of the retractor balloon  236  inflates around the endoscope insertion member  232  to further secure the retractor balloon  236  to the endoscope.  
         [0080]    Once retractor balloon  236  has been inflated to a fully expanded configuration shown in FIG. 11D, the endoscope insertion member  232  is slowly pulled in a proximal direction out of the patient, as indicated by an arrow  268 . During the withdrawal, the endoscopist views the wall of colon CLN″ through three windows or openings defined on the near and far sides by proximal and distal end portions  238  and  240  and on the lateral sides by struts or spacer members  242 ,  244 ,  246 . As it is pulled through colon CLN″, the inflated retractor balloon  236  stretches the wall of colon CLN″ facilitating a viewing of the organ by the endoscopist. The three windows or openings between end portions  128  and  130  and struts or spacer members  242 ,  244 ,  246 , as well as the opening (not separately labeled) encircled by coiled distal end portion  240  permit diagnostic and interventional procedures via endoscope insertion emember  232 . When a polyp PLP″ happens to come into view (FIG. 11F), the withdrawal procedure is interrupted with the retractor balloon  236  framing the polyp. Removal and capture of the polyp PLP″ can then be effectuated via a cauterization snare operation.  
         [0081]    [0081]FIG. 1G depicts retractor balloon  236  in a state of partial collapse after an investigation or intervention has been completed. FIG. 11H depicts retractor balloon  236  in a state of essentially total collapse during a withdrawal of endoscope insertion member  232 . As discussed above, an endoscopic scalpel or other sharp instrument may be inserted through the biopsy channel of the endoscope insertion member  232  and used to puncture retractor balloon  236 , thereby allowing depressurization thereof. Alternatively, if retractor balloon  236  communicates with tube  248  via a two-way valve, then depressurization may be accomplished by applying suction from the proximal end of the tube. In that case, tube  248  must have a transverse rigidity preventing collapse thereof in the presence of internal suction forces.  
         [0082]    Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Fasteners other than a sheath assembly may be provided for securing a balloon-type endoscopic retractor to the distal end of an endoscopic insertion member such as a flexible endoscope. Such fasteners include glue, clamps, elastic bands, and balloon elements, for instance in the shape of a C or an O. The fastener may be a separate element or incorporated into the balloon retractor as a part thereof.  
         [0083]    It is to be noted that the retractor instrument and associated methodology disclosed herein may be used with laparoscopes and othe rigid endoscopes, as well as with flexible endoscopes. Thus, the term “endoscope insertion shaft” or “endoscope insertion member” as used herein refers to any type of endoscope, whether flexible such as a colonoscope or rigid such as a laparoscope.  
         [0084]    The word “endoscopic” as in the term “endoscopic insertion member” is used more broadly herein to denote any type of instrument part inserted into a patient in a minimally invasive surgical procedure involving a flexible or rigid endoscope. For example, an endoscopic insertion member may be a laparoscopic forceps insertable through a trocar sleeve or cannula into a patient for use in a laparoscopic procedure. A balloon retractor in accordance with the invention may be attached about the distal end of the forceps for spreading tissues to facilitate use of the forceps.  
         [0085]    The word “spiral” or “spiraling” is used herein to denote a configuration of an elongate member wherein than member is wound about an axis. A coil is a spiral where successive turns are in close juxtaposition or adjacent to one another.  
         [0086]    Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.