Patent Publication Number: US-7905830-B2

Title: Sheath for use with an endoscope

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to the following patent applications, which are hereby incorporated by reference: U.S. Ser. Nos. 10/440,957 (published as US 2004/0230095); 10/440,660 (published as US 2004/0230096); and U.S. 10/440,956 (published US 2004/0230097); each filed May 16, 2003. 
     This application claims priority to and incorporates by reference U.S. patent application “Medical Instrument Having a Guidewire and an Add-to Catheter”, filed May 12, 2005 in the name of Long et al. having a Ser. No. of 11/128.108. 
     FIELD OF THE INVENTION 
     The present invention is related generally to medical devices and more particularly to devices and methods useful in endoscopic procedures. 
     BACKGROUND OF THE INVENTION 
     Minimally invasive procedures are desirable because such procedures can reduce pain and provide relatively quick recovery times as compared with conventional open medical procedures. Many minimally invasive procedures are performed with an endoscope (including without limitation laparoscopes). Such procedures permit a physician to position, manipulate, and view medical instruments and accessories inside the patient through a small access opening in the patient&#39;s body. Laparoscopy is a term used to describe such an “endosurgical” approach using an endoscope (often a rigid laparoscope). In this type of procedure, accessory devices are often inserted into a patient through trocars placed through the body wall. 
     Still less invasive treatments include those that are performed through insertion of an endoscope through a natural body orifice to a treatment site. Examples of this approach include, but are not limited to, cystoscopy, hysteroscopy, esophagogastroduodenoscopy, and colonoscopy. Many of these procedures employ the use of a flexible endoscope during the procedure. Flexible endoscopes often have a flexible, steerable articulating section near the distal end that can be controlled by the user by utilizing controls at the proximal end. 
     Some flexible endoscopes are relatively small (1 mm to 3 mm in diameter), and may have no integral accessory channel (also called biopsy channels or working channels). Other flexible endoscopes, including gastroscopes and colonoscopes, have integral working channels having a diameter of about 2.0 to 3.5 mm for the purpose of introducing and removing medical devices and other accessory devices to perform diagnosis or therapy within the patient. As a result, the accessory devices used by a physician can be limited in size by the diameter of the accessory channel of the scope used. Additionally, the physician may be limited to a single accessory device when using the standard endoscope having one working channel. 
     Certain specialized endoscopes are available, such as large working channel endoscopes having a working channel of 5 mm in diameter, which can be used to pass relatively large accessories, or to provide capability to suction large blood clots. Other specialized endoscopes include those having two working channels. One disadvantages of such large diameter/multiple working channel endoscopes can be that such devices can be relatively expensive. Further, such large diameter/multiple working channel endoscopes can have an outer diameter that makes the endoscope relatively stiff, or otherwise difficult to intubate. 
     Various references describe methods or systems related to an endoscope, such as for example: U.S. Pat. No. 5,025,778, Silverstein; U.S. Pat. No. 4,947,827, Opie; US 2002/107530 published Aug. 8, 2002 in the name of Sauer; U.S. Pat. No. 6,352,503, Matsui. One disadvantage of known systems is the potential for the distal end of a device used externally of an endoscope to move, which may cause the accessory to lack precision or the ability to be maintained within a desired field of view of the imaging capability of the endoscope. 
     WO 00/48506 published Aug. 24, 2000 in the name of Herrmann discloses a deformable endoscope with at least one supplementary device. The unit comprising the endoscope and the supplementary device is said to have a non-round cross-section. Such a non-circular endoscope may be disadvantageous from the point of view of cost, complexity, or ease in cleaning/sterilization. For instance, a standard endoscope with a smooth, substantially-circular cross section can be relatively easy to sanitize and clean. 
     WO 00/48506 published Aug. 24, 2000 in the name of Kortenbach, discloses methods and devices for delivering a medical instrument over the exterior of an endoscope to allow the use of instruments too large to fit through the lumena of the endoscope. Kortenbach discloses a collar for use with an endoscope, resilient straps, a flexible sheath having a reclosable seam, flexible polymer extrusions, and a floppy tangential sheath defining a lumen having an irregular (collapsible) cross section. Kortenbach also discloses a track with an inverted T configuration. 
     Endoscopes may also be used with feeding tubes. For instance, it is known to advance a feeding tube through an internal channel of an endoscope. It is also known to advance a feeding tube together with an endscope, such as by holding the distal end of the feeding tube with a pair of forceps extending from a distal end of the endoscope, and “dragging” the feeding tube along the outside of the endoscope while advancing the endoscope to a desired location. 
     Investigators have reported that a conventional pull method of PEG placement may be supplemented with an overtube to reduce risk of peristomal infection. “Efficacy of an Overtube for Reducing the Risk of Peristomal Infection after PEG Placement: a Prospective, Randomized Comparison Study” Iruru Maetani, MD, et al., Gastrointestinal Endoscopy, Volume 61, No. 4, 2005, hereby incorporated by reference, discloses the use of an overtube during PEG placement. 
     Still, scientists and engineers continue to seek improved devices and methods for the introducing medical devices into the gastro-intestinal tract, including improved devices and methods for placing feeding tubes in patients. 
     SUMMARY OF THE INVENTION 
     The present invention provides methods and devices useful with various medical procedures, including without limitation methods and devices useful with endoscopes, methods and devices employed through naturally occurring body orifices, and methods and devices related to placement of feeding tubes. For instance, in one embodiment, the present invention can be used to quickly and consistently place an accessory, such as a feeding tube, in a desired location, such as in the stomach or the jejunum, and such that the device stays in the desired position during removal of the endoscope. In certain embodiments, the present invention can be employed to reduce the number of intubations needed for certain procedures, such as the number of intubations needed to place a feeding tube. In certain embodiments, the the present invention can also be employed to reduce the number of steps required in certain medical procedures, such as by reducing the oral to nasal transfer steps in feeding tube installation, reducing the number of times tools or devices are switched or deployed in the body, reducing the number of hands required to perform a procedure, and/or reducing the number of times the medical professional must change hand position during a procedure. 
     In one embodiment, the invention provides a sheath for use with an endoscope. The sheath can have an inside surface which is non-smooth. The sheath can have a thickness of less than about 0.010 inch, and the inside surface of the sheath can be textured with surface features occurring at regular or irregular intervals. 
     In certain embodiments, the invention can be employed with respect to procedures involving Percutaneous Endoscopic Gastrostomy (PEG) tubes and/or Jejunal Enteral Tube through a Percutaneous Endoscopic Gastrostomy (JET PEG) procedures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a schematic illustration of an endoscopic sheath and track. 
         FIG. 1A  is a schematic illustration of an endoscope inserted into a handle having a hinged latch in an open configuration. 
         FIG. 1B  is a schematic illustration similar to that of  FIG. 1A  showing the hinged latch in a closed position and feeding tube and carrier being advanced on a track. 
         FIG. 2  is a schematic illustration of the distal end of the sheath of  FIG. 1  showing a carrier being advanced on the track. 
         FIG. 2A  is a schematic isometric illustration showing the proximal end of the endcap. 
         FIG. 3  illustrates different sections of a track disposed on a sheath. 
         FIG. 4  is a top view illustration of a portion of a track. 
         FIG. 5  is a cross-sectional illustration of a track supported on a sheath (it being understood that the sheath may be formed of a thin film that would not maintain the circular configuration shown in  FIG. 5  absent an internal member, such an endoscope, being disposed within the sheath). 
         FIG. 6  is a schematic illustration of a feeding tube carrier in accordance with one embodiment of the present invention. 
         FIG. 7  is a schematic illustration of a distal portion of a sheath and track showing a carrier advanced to a distal position on the track, and with an indicator tab extending through a slot in an endcap to be viewable by an endoscope. 
         FIG. 8  is a schematic illustration showing the distal end of an endoscope being advanced through a sheath, with the sheath, track, and carrier shown in cross-section. 
         FIG. 9  is a schematic illustration of a distal portion of a sheath, track, and carrier, and illustrating the carrier and a feeding tube advanced to a distal position on the track. 
         FIG. 10  is a schematic illustration of a feeding tube having a feature for providing sliding engagement with a track. 
         FIG. 11  is a schematic illustration of the proximal portion of the feature shown in  FIG. 10 . 
         FIG. 12  is a schematic illustration of a port for use in maintaing the feeding tube in a desired position in the gastrointestinal tract after the feeding tube is positioned and the track has been withdrawn from the GI tract. 
         FIG. 13  is a schematic side view illustration of a distal portion of the feeding tube shown in  FIG. 10 , illustrating a distal portion of a passageway (in phantom) through which nutrients may be directed, such that the distal portion of the passageway does not have to bend or curve to communicate with a distal feeding port, with the portion of the feeding tube extending distally of the distal feeding port being inclined with respect to the passageway, and the figure illustrating weights (in phantom) which may be employed at a distal end of the feeding tube. 
         FIG. 14  is a schematic illustration of a distal portion of a member which may be employed to maintain the feeding tube in a desired position during removal of the endoscope and the carrier from the patient&#39;s GI tract. 
         FIG. 15  is a schematic illustration of the distal end of the member of  FIG. 14  and showing contact surfaces positioned, sized, and/or shaped for engaging contact surfaces on the proximal end of a rail feature associated with a feeding tube. 
         FIG. 16  is a schematic illustration of the distal portion of the member of  FIG. 14  positioned with respect to the proximal end of the rail feature on the feeding tube. 
         FIG. 17  is a schematic bottom view illustration of adjacent portions of the rail feature on the feeding tube and the member of  FIG. 14 . 
         FIG. 18  illustrates introducing an endoscope in a medical device (which medical device can include a handle, sheath, endcap, and track) into the GI tract of a patient, such that the endcap and the distal end of the track are positioned in the small intestine (such as in the jejunum). 
         FIG. 19  illustrates advancing a carrier and a feeding tube together on the track after the endoscope and track have been positioned as shown in  FIG. 18 , so that the distal end of the feeding tube is positioned in the jejunum. 
         FIG. 20  illustrates feeding a member distally to a position behind the feeding tube to hold the feeding tube in place in the GI tract while the endoscope and medical device (which medical device can include a handle, sheath, endcap, and track) are removed in a proximal direction from the patient. 
         FIG. 21  illustrates the feeding tube positioned to extend from outside the mouth to the small intestine. 
         FIG. 22  illustrates providing a transfer tube through the nose. 
         FIG. 23  illustrates associating an end of the transfer tube with the proximal end of the feeding tube. 
         FIG. 24  illustrates the proximal end of the feeding tube pulled through the throat and the nasal cavity (such as with the transfer tube of  FIG. 23 ) such that the proximal end of the feeding tube extends from the patient&#39;s nose (from a nostril). 
         FIG. 25  illustrates positioning an endoscope within a medical device (which medical device can include a handle, sheath, endcap, and track) into the GI tract such that the endcap and the distal end of the track are disposed in the stomach, such as for use in a PEG tube feeding method, and  FIG. 25  illustrating a cannula/needle for providing a percutaneous incision through the abdominal wall can be transilluminated with a light source associated with the endoscope. 
         FIG. 26  illustrates removing the needle from the cannula and introducing a looped guidewire through the cannula, and illustrating the distal end of the endoscope, endcap, sheath, and track passing through the loop of the looped guidewire. 
         FIG. 27  advancing a PEG tube (such as a PEG tube having a length substantially less than the length of the track) on the track, with the PEG tube disposed on the track such that a first end of the PEG tube to be positioned inside the body is advanced ahead of a second end of the PEG to be positioned through the percutaneous incision, and showing the first end of the PEG tube being advanced off of the track. 
         FIG. 28  illustrates the second end of the PEG tube advanced off of the rail and grasping a length of suture extending from the second end of the PEG tube with the looped guidewire. 
         FIG. 29  illustrates pulling the suture loop and the second end of the PEG tube through the percutaneous incision and seating a bumper member at the first end of the PEG tube against the inside surface of the gastric wall, with the endoscope positioned to provide viewing of the seating. 
         FIG. 30  illustrates the medical device and endoscope removed from the GI tract and the external portion of the PEG tube adapted for introducing nutrients through the abodiminal wall. 
         FIG. 31  illustrates positioning an endoscope (such as a gastroscope) disposed in a medical device (which medical device can include a handle, sheath, endcap, and track) into the GI tract such that the endcap, the distal end of the gastroscope, and the distal end of the track are disposed in the stomach, such as for use in a JET-PEG tube feeding method, with  FIG. 31  also showing the endoscope can be used to transilluminate the abdominal wall, such that a needle/cannula can be used to make and/or pass through a small incision into the stomach. 
         FIG. 32  illustrates removing the needle and introducing a looped guidewire through the cannula, after which the medical device (with gastroscope disposed therein) can be advanced through the looped guidewire, with the distal end of the medical device and the distal end of the gastroscope being advanced into the jejunum (such as past the Ligament of Treitz) 
         FIG. 33  illustrates positioning a feeding tube (such as a feeding tube having a length substantially less than the length of the track) and carrier on the track, and advancing the feeding tube along the track until the distal end of the feeding tube is positioned in the jejunum and can be viewed by the endoscope. 
         FIG. 34  illustrates retracting the medical device and gastroscope proximally into the stomach, while holding a member positioned proximally behind the feeding tube to push the feeding tube off the distal end of the track, and illustrating grasping a length of suture extending from the feeding tube with the looped guidewire. 
         FIG. 35  illustrates pulling the suture and an end of the feeding tube through the incision through the abodiminal wall, and leaving a distal end of the feeding tube in the jejunum. 
         FIG. 36  illustrates the external portion of the feeding tube adapted for introducing nutrients through the abodiminal wall, with the distal end of the feeding tube being positioned in the jejunum. 
         FIG. 37  illustrates the feeding tube in place with the gastroscope and medical device removed. 
         FIG. 38  illustrates an endcap loading element which can be used to an endcap on the distal end of an endoscope. 
         FIG. 38A  is a cross-sectional schematic illustration of a flexible prong of the endcap loading element. 
         FIG. 39  illustrates the endcap loading element disposed on the distal end of the endoscope, and the endoscope disposed in the sheath, with the flexible prongs of the endcap loading element disposed within the sheath and engaging an outer surface of the endoscope, with an O-ring compressing the flexible prongs and positioned against the proximal face of the endcap, and with a distal portion of the endcap loading element extending through the bore of the endcap. 
         FIG. 40  illustrates a handle sliding proximally on the endcap loading element to be positioned against the distal face of the endcap. 
         FIG. 40A  is a schematic illustration showing the proximal face a handle and showing an endcap loading element extending into a central bore in the handle. 
         FIG. 41  illustrates a ring which can be attached to a distal portion of the endcap loading element. 
         FIG. 42  illustrates pulling distally on the ring while pushing proximally on the handle, to provide a pushing force on the distal face of the endcap with the handle, while providing a pulling traction force on the outer surface of the endoscope with the flexible prongs, such that the end cap and the O-ring slide off of the endcap loading element and onto the distal end of the endoscope. 
         FIG. 43  illustrates a schematic isometric view of an apparatus that engages an internal surface of an endoscope and can be used to push an endcap onto an endoscope. 
         FIG. 44  is cross-sectional, schematic illustration of the apparatus of  FIG. 43 . 
         FIG. 45  is a schematic isometric illustration showing the distal end of an endoscope, the endcap, and the forward portion of the apparatus of  FIG. 43  with a portion of the apparatus being inserted into a working channel of the endoscope. 
         FIG. 46  is a schematic isometric illustration showing expansion of a portion of the apparatus inserted into the working channel of the endoscope. 
         FIG. 47  is a schematic isometric illustration showing rearward movement of an actuator of the apparatus of  FIG. 43  to push the endcap onto the endoscope in a first direction while pulling the endoscope in the opposite direction. 
         FIG. 48  is a cross-sectional, schematic illustration of a portion of the apparatus of  FIG. 43 . 
         FIG. 49  is a cross-sectional, schematic illustration of a portion of the apparatus of  FIG. 43 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  illustrate a medical apparatus  10  according to one embodiment of the present invention. In one embodiment, apparatus  10  can include a handle  100 , a flexible catheter or sheath  200  extending from handle  100 , a flexible track  300  disposed on the sheath  200 , and an endcap  400  disposed at the distal end of sheath  200 . Handle  100  and flexible sheath  200  can each be sized to receive an endoscope therethrough. 
     Apparatus  10  can also include a carrier  500  which is adapted to slidably engage track  300 , as shown in  FIG. 2 . Endcap  400  can be sized and shaped to engage the distal end of an endoscope, such as an endoscope  1000  as shown in  FIG. 2 . Endoscope  1000  can be any commercially available endoscope, such as a gastroscope or colonoscope having an articulating distal section, and including a viewing element  1100  and a working channel  1200 . Any suitable endoscope, including without limitation gastroscopes and pediatric colonscopes can be used with the present invention. Suitable endoscopes for use with the present invention include, without limitation, model PCF100, PCF130L, PCF140L, or PCF160AL endoscopes manufactured by Olympus Corporation of Japan. The handle  100 , sheath  200 , and endcap  400  can be sized to receive various diameter endoscopes, such as, but not limited to, endoscopes having a diameter from about 9 mm to about 14 mm. 
     To introduce the endoscope  1000  with the apparatus  10  into a patient, the operator may start with a clean dry endoscope. The sheath  200  is preferably formed of a thin, light weight, drapable polymeric film material which can be relatively soft and elastically extensible, and which has substantially no torsional stiffness and no torsional load carrying capability. By “drapable” it is meant that the sheath does not maintain a circular or other regular cross-sectional shape in the absence of an internal structure (such as an endoscope) supporting the sheath. 
     In one embodiment, the sheath  200  can be formed of a material having an elastic modulus of less than about 20 ksi, more particularly less than about 15 ksi, still more particularly less than about 10 ksi, and even more particularly less than about 7 ksi. The sheath can be formed of a material having a yield strength of less than about 500 psi, more particularly less than about 300 psi, still more particularly less than about 200 psi, and still more particularly less than about 125 psi. In one embodiment, the sheath can be formed of a material having a yield strength of between about 90 psi and about 120 psi. The elastic modulus and yield strength can be determined as an average of five or more measurements, and can be determined using ASTM test #D882 (Standard Test Methods for Tensile Properties of Thin Plastic Sheeting) using a gage length of 4.0 inch, a gage width of 1.0 inch, a test thickness equal to the thickness of the film (e.g about 0.005 inch), and a test machine speed of 0.4 in/minute. In one embodiment, the sheath can be formed of a film have a modulus of less than about 7 ksi, a yield strength of less than about 125 psi, and a tensile strength at break (measured according to ASTM D 638) of at least about 1 M Pa (mega Pascal), more particularly at least about 5 Mpa, and still more particularly about 10 Mpa or greater. The sheath can be formed of a film having a tensile elongation (measured using ASTM D 638)of at least about 200 percent, more particularly at least about 500 percent, and still more particularly about 800 percent or more. The modulus, yield strength, tensile strength, and elongation are determined as mean of at least five measurements. 
     In some embodiments, it can be desirable that the sheath  200  can be inserted over the insertion length of the scope without use of a lubricant. In one embodiment, the sheath  200  can have a non-smooth, textured inner surface  210  that prevents the inner surface of the flexible sheath from “sticking” to outer surface of the insertion portion of the endoscope. The textured inner surface can also aid in gripping the endoscope through the sheath  200 , such as for example if it is desired to rotate the sheath and endoscope together. The inner surface can be textured and the outer surface can be generally smooth, or both the inner and outer surfaces may be textured. The inner surface of the sheath  200  may have the same texture as the outside surface, be relatively more textured than the outer surface, or be relatively less textured than the outside surface. 
     The textured inner surface can be provided with elevated portions, depressed portions, or combinations of elevated and depressed portions. For instance, the inner surface can include randomly spaced bumps or protrusions, or alternatively, can be provided by raised portions (such as bumps, ribs or protrusions ) that occur at regularly spaced intervals, which intervals may be of generally uniform spacing. The texture of the inner surface can be measured in terms of a roughness average measurement, where “roughness average” or “Ra” is the arithmetic average of the absolute values of the measured profile height deviations divided by an evaluation length, as set forth on page 728 of the 27 st  edition of Machinery&#39;s Handbook, 2004, incorporated herein by reference. The roughness average can be measured using optical interferometry with a Zygo NewView 100 3D Imaging Surface Structure Analyzer marketed by Zygo Corporation of Middlefield, Conn. The following measurement parameters and analysis parameters can be used: 
     Measurment Parameters: Acquisition Mode is “Scan”; Camera Mode is 320×240 Normal; Phase Controls (AGC is “ON”; Phase res is “High”; Min Mod is 1%; Min Area size is 7; Discon Action is “Filter”; Connection Order is “Location”; Remove Fringes is “Off”; Image Zoom is 1×); Scan Controls (Scan length is “Extended”; Extended Scan Length is 11000 micro inches; FDA Res is “Low”). 
     Analysis Parameters: Filter is “Lowpass”; Filter Type is “Average”; Filter Window Size is 13; Filter High Freq. 1/mil; Filter Low Freq. 1/mil; Filter Trim is “Off”; Remove is “Plane”; Trim is 0; Remove Spikes is “ON”; Spike Height(xRMS) is 1.25; Data Fill is “ON”; Data Fill Max is 25. The measurements can be made with a 5× Michelson Objective Lens, and the samples can be coated with gold or otherwise coated to provide an generally opaque surface that reflects light. Gold coating can be applied with a Hummer 6.2 Sputtering System. 
     In one embodiment, the inner surface of the sheath  200  can a have a roughness average value Ra of less than about 500 micro inch (0.000500 inch), more particularly less than about 400 micro inch, still more particularly less than about 250 micro inch, and still more particularly less than about 150 micro inch. In one embodiment, the roughness average value of the inner surface can be between about 50 and about 500 micro inch, more particularly between about 50 and about 250 micro inch, and still more particularly between about 75 and about 125 micro inch. The roughness average value is determined as a mean of at least five measurements. 
     The inner surface of the sheath  200  can have a coefficient of friction which is suitable for gripping the endoscope with the sheath  200 , but which also allows the endoscope to be positioned within the sheath without excessive effort. A suitable inner surface can have a coefficient of static friction and a coefficient of sliding friction which can both be less than about 1.0. In one embodiment, the coefficient of static friction can be between about 0.3 and about 0.6 (more particularly between about 0.4 and 0.5) and the coefficient of sliding friction can be between about 0.3 and about 0.6 (more particularly between about 0.4 and about 0.5) using a friction sled formed of Ultem 1000 material. The coefficient of static friction can be between about 0.2 and about 0.5 (more particularly between about 0.3 and about 0.4) and the coefficient of sliding friction can be between about 0.2 and about 0.5 (more particularly between about 0.3 and about 0.4) using a friction test sled formed of 440C stainless steel. The coefficient of static and sliding friction can be measured using ASTM test #D1894 (Standard Test Method for Static and Kinetic Coefficients of Friction of Plastic Film and Sheeting). The coefficient of friction is determined as a mean of at least five measurements. 
     In one embodiment, the sheath  200  can be formed of a thermoplastic polyolefin film having a thickness of less than about 0.010 inch, and can comprise polypropylene, polyethylene, and mixtures thereof. In one embodiment the sheath can be formed of a film having a thickness of between about 0.004 to 0.006 inch, more particularly about 0.005 inch. One suitable film is available as Basell Softell Q020F made by Basell NV, Hoofdorp, Netherlands, such as can be provided by Specialty Extrusion, Inc. of Royersford, Pa. 
     The handle  100  can be formed of any suitable material, including without limitation relatively rigid biocompatible metals and plastics. One suitable material from which handle  100  can be formed is molded polypropylene, such as is available as Huntsman 12N25ACS296 from Huntsman Corp. of Houston Tex. 
     As shown in  FIG. 1 , handle  100  can have a generally cylindrical proximal section  102  having a proximal opening for receiving an endoscope, and an adjacent distally converging conical section  104 . The handle  100  includes an opening  101  at it&#39;s proximal end for receiving an endoscope. The handle&#39;s internal channel for receiving the endoscope can include a generally cylindrical channel section  103  (shown in phantom) corresponding to section  102 , and a generally conical channel section  105  (shown in phantom) corresponding to section  104 . The generally conical channel section  105  can taper from a relatively larger inner diameter to a relatively small inner diameter as the channel section  105  extends distally. A track support structure  120  is shown extending from sections  102  and  104  to support a track ramp  130  at an inclined angle with respect to the longitudinal axis of sections  102  and  104 . Track ramp  130  can support the proximal portion of the track  300 . 
       FIGS. 1A and 1B  illustrate isometric views of an endoscope  1000  inserted into handle  100 . A hinged latch  140  can be positioned at or adjacent to the proximal end of track  300 . The latch  140  can be hinged to the track ramp  130  or structure  120 , such as by a living hinge or a mechanical pin type hinge. The latch is shown in an open position in  FIG. 1A  and a closed position in  FIG. 1B . The latch, when in the closed position, extends over the track  300  at or adjacent the proximal end of the track and can assist in preventing components slidably supported on track  300  from “unzipping” from track  300  or otherwise being dislodged from track  300  during use. In  FIG. 1B , a carrier  500  and feeding tube  600  (both described in more detail below) are shown being advanced by hand in a distal direction along track  300 . 
     An elastically extensible member can be employed to provide a distal biasing force on the endoscope and a proximal biasing force on the handle  100 . For instance, the handle  100  can include an elastic strap  150  (shown in  FIG. 18 and 19 ). The elastic strap can extend from a portion of the handle  100 , such as the track ramp  130  or the structure  120 , to form a loop that encircles a portion of the endoscope  1000 , such an endoscope accessory channel port. The elastic strap  150  is useful for accommodating variation in endoscope lengths, assists in maintaining tautness of the sheath, and assists in maintaining engagement of the endoscope in the handle. The elastic strap can be employed to compensate for length changes due to scope bending, and to provide a reslient biasing force urging the endoscope distally into the handle and sheath. Alternatively, instead an elastic strap, a relatively inelastic strap could be used, and a biasing member could be employed in the handle or sheath to maintain the sheath and track from pleating or otherwise “bunching” on the endoscope. For instance, the strap could be generally inextensible, and the handle could be formed of an elastically extensible material or geometry, such that the length of the handle would be extended when the strap was engaged on relatively longer endoscope. 
     Endcap  400  can be formed of a thermoplastic elastomer for fitting on the distal end of the endoscope  1000 . The endcap  400  can be formed of a material having a durometer of less than about  100 , and more particularly between about 50 and about 90 (as measured using the A scale, 0.120 inch test according to ASTM D2240). The endcap can be pressed onto (e.g. slightly expanded to fit over) the distal end of the endoscope with the distal end of the endoscope being gripped by the endcap  400 . One suitable material from which endcap  400  can be formed is molded Santoprene brand thermoplastic elastomer. Providing an endcap  400  from a material such as a thermoplastic elastomer can be desirable in that such an endcap  400  can be pressed onto the distal end of the endoscope, as described in more detail below. 
     Referring to  FIGS. 1 ,  2 , and  2 A, the endcap  400  can include a generally cylindrical body portion  410 , a distal face  412 , a proximal face  414 , and a central bore opening  420  therethrough for receiving the distal end of the endoscope  1000 . The endcap  400  can have internal, circumferentially extending grooves  422  spaced apart along the length of the internal surface of central bore opening  420 . A track recess  424  ( FIG. 2A ) can provided in the upper half of body portion  410 . The recess  424  can extend distally from the proximal face  414 , and can be sized and shaped to receive the distal end of the track  300 . If desired, the proximal edge of the bore opening  420  can be tapered or chamfered to assist in pressing the endcap onto the distal end of the endoscope. 
     The endcap  400  can also include a slot  430  ( FIG. 2 and 2A ) extending through at least a portion of the body portion  410  and opening on the distal face  412 . Slot  430  can extend distally from a surface bounding track recess  424 , to be disposed with respect to track  300  to be at generally the same “o&#39;clock” position as track  300 . Slot  430  can be sized and shaped to receive a tab or other indicator device, as described below. In one embodiment, the proximal end of slot  430  can be generally aligned with channel  320  in track  300  (described below), and the distal end of slot  430  can be inclined radially inwardly as the slot  430  extends from recess  424  in the distal direction, such that a tab or other indicator device extending through slot  430  is directed distally and radially inwardly to be viewable by the optics of the endoscope  1000 . The Endcap  400  can be joined to the distal end of the sheath  200  by any suitable method, such as ultrasonic welding. 
     Track  300  can be supported by sheath  200 , and can extend from handle  100  to the endcap  400 .  FIG. 3  shows track  300  supported on sheath  200  with a portion of the track shown in phantom.  FIG. 4  illustrates a top plan view of the track  300 , and  FIG. 5  illustrates a cross-sectional view of track  300  supported by sheath  200 . In  FIG. 5 , the sheath  200  is shown in cross-section as it would appear if disposed on an endoscope for illustration purposes, with it being understood that, in one embodiment, the wall of the sheath  200  can be generally flaccid and drapable, and lack sufficient stiffness to maintain the shape shown in  FIG. 5  without the support of the endoscope or other internal support. 
     Track  300  can be a generally continuous, unitary piece of material which extends longitudinally a length sufficient to reach from a point outside the patient to a point in or distal to the stomach of the patient, such as through the pylorus and into the small intestine. Track  300  can be formed of a flexible polymeric material, such as extruded polypropelene. One suitable material from which track  300  can be formed is Huntsman 23R2Acs321 available from Huntsman Corp. of Houston Tex. The sheath  200  can be joined to the track  300  by any suitable joining method, such as by ultrasonic welding. The distal end of the track  300  can be over molded onto the end cap  400 , or otherwise joined to end cap  400  in recess  424 . The handle  100  can be joined to the proximal end of the sheath  200  and the proximal end of the track  300  by any suitable method, such as by ultrasonic welding. 
     Track  300  can include a generally C shaped channel body  310  defining an inverted T-shaped channel  320  in cross section. The body  310  can include floor  312 , upstanding side walls  314 , and inwardly extending prongs  316 . The body  310  can also include a plurality of circumferentially extending side tabs  330  extending outwardly from body  310 . Adjacent tabs  330  on each side of the track  300  can be spaced apart, such as by the scalloping (shown in  FIG. 3  in phantom), or by other spacing methods, such as notching, to maintain the flexibility of the track  300 . The tabs  330  are shown joined to the inner surface  210  of the sheath  200 . Tabs  330  can be joined to the inner surface  210  by any suitable means, such as with adhesive or other bonding methods. 
     Without being limited by theory, the tabs  330  can be employed to stabilize the track  300  with respect to the endoscope when the endoscope is positioned in sheath  200 . The tabs help to maintain radial alignment of the axis of symmetry of the track channel  320  with respect to the endoscope  1000 . Accordingly, the sheath  200  and the track  300  can be rotated circumferentially as a unit about the endoscope  1000  to different o&#39;clock positions, and the tabs  330  help to maintain the track  300  (and channel  320 ) in proper radial orientation with respect to the endoscope. The desired radial orientation of channel  320  is illustrated in  FIG. 5 , with the cross-sectional centerline and axis of symmetry of channel  320  being generally aligned with a radial line extending from the center of the the endoscope. 
     According to one embodiment of the present invention, the track  300  has at least one portion which has a greater flexibility than another portion of the track. For instance, the track  300  can include a portion having a bending flexibility and axial flexibility that is greater than the bending flexibility and axial flexibility of another portion of the track. Referring to  FIG. 3 , the track  300  is shown schematically to have three sections of different flexibility. Section A, which can be the distal most portion of the track  300 , can be the most flexible portion of the track in both bending and axial extension. Section A can be associated with the distal most portion of the endoscope, such as an articulating portion of the endoscope. Section B can be relatively less flexible (more stiff) than Section A. Section C can be the proximal portion of the track  300  and can be relatively less flexible than region B. In one embodiment, Section A can extend about 10 inches, and Section B can extend about 26 inches. In one embodiment, the length of the track  300  can be at least about 50 inches. 
     In the embodiment shown in the Figures, Sections A and B are interrupted at intervals along their respective lengths to reduce the bending stiffness and the axial stiffness of the regions, while Section C can be generally uninterrupted. The interruptions in Sections A and B are provided by a series of slits  340 . As shown in  FIGS. 3 and 4 , the slits  340  on the two sides of the track body  310  are staggered (longitudinally offset) relative to each other such that the slits on one side of the track body  310  are not aligned with the slits on the other side of the track body  310 . In the embodiment shown, each slit  340  on one side of the track is positioned halfway between the two adjacent slits on the opposite side of the track. Each of the tabs  330  can be positioned between a pair of adjacent slits  340 . In one embodiment, the slits  340  can have a width (measured parallel to the length of channel  320 ) of less than about 0.010 inch, more particularly, less than about 0.005 inch. The slits  340  can be formed by any suitable knife or other cutting instrument. Without being limited by theory, the width and staggering of the slits  340  can provide sufficient flexibility of the track  300 , while preventing a member slidably disposed in the track from “unzipping” from the carrier, or “popping out of” the track, such as by deflection of prongs  316 , at positions where the endoscope is bent (or other configuration where the track is bent or otherwise to take on a curved configuration). The provision of selectively placed interruptions in the track permits the track to follow the curvature of the endoscope without significantly increasing the bending stiffness of the assembly of the sheath  200  and endoscope. 
     In one embodiment, the slits  340  extend through the full thickness of the track (thickness as measured in the vertical direction in  FIG. 5 ). Additionally, the slits can extend from one side of the track to extend across the full the width of one of the prongs  316 , and the slits can extend at least halfway across the floor  312 . 
     In the embodiment shown in  FIGS. 3 and 4 , each of the slits  340  can extend through the full thickness of the track. Additionally, depending upon the location of the slits  340  along the length of the track, the slits  340  can extend more than halfway, but not fully across the width of the track. For instance, the slits  340  extend across the longitudinal centerline of the track in Section A of  FIG. 3 . Referring to  FIG. 5 , the dimension W illustrates the width of a slit extending more than halfway, but not fully across the width of the track. The spacing  342  ( FIG. 3 ) between slits  340  on the same side of the track  3090  can be about 0.120 to about 0.130 inch in Section A and about 0.250 inch in Section B. 
     The staggered arrangement of slits  340  that extend beyond the centerline of the track can provide the advantage that the track  300  does not have a longitudinally continuous load path for carrying tensile loads or bending loads. Without being limited by theory, the staggered arrangement of slits  340  can be viewed as providing bending sections (indicated by reference number  344  in  FIG. 4 ) in the track  300 . The bending sections  344  can have a length  346  ( FIG. 4 ) defined by the amount the slits  340  on opposite sides of the track overlap, and the bending sections  344  have a width  348  defined by the longitudinal spacing of one slit from the immediately adjacent slit extending from the opposite side of the track. In one embodiment, the length  346  can be about 0.038 inch to about 0.040 inch in Section A, and the width  348  can be about 0.0625 inch. 
       FIG. 6  illustrates carrier  500 , and  FIG. 7  illustrates carrier  500  advanced to distal most position on track  300 . Carrier  500  can extend from a proximal end  502  to a distal end  504 . The length of carrier  500  can be a length sufficient to reach from a point outside the patient to a point within, or distal to, the patient&#39;s stomach. In one embodiment, the length of carrier  500  can be at least about 100 cm, and more particularly at least about 72 inches. The carrier  500  can include a body  520 , a generally vertically extending web  530 , and a track engaging rail  534 . Carrier  500  slidably engages track  300 , with rail  534  being sized and shaped to be slidable within channel  320  of track  300 . Carrier  500  can be of unitary construction, and can be molded or otherwise formed of a suitable material. In one embodiment, carrier  500  is formed of a relatively low friction materials, such as extruded PTFE (Teflon). 
       FIG. 8  provides a cross-sectional illustration of carrier  500  supported on track  300 , with the distal end of endoscope  1000  illustrated being advanced through the cross-section section to illustrate one position of components on the endoscope&#39;s distal end relative to the position of the track  300 . As shown in  FIG. 8 , the web  530  extends generally radially inwardly from body  520 , to position the rail  534  radially inward of the carrier body  520 . The cross-section of web  530  and rail  534 , together, can provide a generally inverted “T” configuration. 
     The carrier body  520  can include a channel  522 . Channel  522  can extend substantially the full length of body  520 . The channel  522  can be bounded by a channel floor  512  and oppositely facing sidewalls  514 . The body  520  can also include inwardly extending prongs  516  having oppositely facing sides  518  which are spaced apart to define the throat of the opening of channel  522 . 
     The distal most portion of the track engaging rail  534  can extend distally beyond body  520  to provide a flexible indicator tab  536 . Tab  536  can be sized and shaped to be received by slot  430  in endcap  400 . As the carrier  500  is advanced distally on track  300 , the tab  536  will be viewable by the optics of endoscope  1000  once the carrier  500  has reach its distal most position on track  300 . Referring to  FIGS. 7 and 8 , the tab  536  can be viewed through endoscope optics element  1100  as tab  536  is advanced distally and radially inwardly from the distal end of slot  430 . 
     In one embodiment, the carrier  500  has at least one portion which has a greater flexibility than another portion of the carrier For instance, the carrier  500  can include a body  520  having a distal portion  520 A having a bending flexibility and axial flexibility that is greater than a more proximal body portion  520 B of the carrier. Referring to  FIG. 6 , the carrier is shown schematically to have two sections of different flexibility. Carrier section  520 A can be the distal most portion of the carrier, and can be the most flexible portion of the carrier in both bending and axial extension. Section  520 A can have a length of at least about 2 inches. In one embodiment, the length of Section  520 A is between about 4 inches and about 10 inches, and more particularly, the length of section  520 A can be between about 6 and about 8 inches. 
     In the embodiment shown in the Figures, body section  520 A is shown interrupted at intervals along its length to reduce the bending stiffness and the axial stiffness of the distal portion of the body  520 . The interruptions can be provided by a series of slits  540 . As shown in  FIGS. 6 and 7 , the slits  540  on the two sides of the carrier body  520  are staggered (longitudinally offset) relative to each other such that the slits on one side of the body  520  are not aligned with the slits on the other side of the body  520 . In the embodiment shown, each slit  540  on one side of the carrier body is positioned axially halfway between the two adjacent slits on the opposite side of the track. Adjacent prongs  516  can be separated by slits  540 . 
     Without being limited by theory, the flexible tab  536  and the slits  540  can help to prevent the distal portion of the carrier  500  from “jumping out” of or “unzipping from” the track. For instance, flexible tab  536  can “bridge” the space between the slits  340  in track  300  to help prevent the carrier from being discharged radially from the track  300 . Without being limited by theory, the width and staggering of the slits  540  can also provide sufficient flexibility of the carrier  500 , while preventing a member slidably disposed in the carrier from “unzipping” from the carrier, or “popping out of” the carrier. 
     In one embodiment, the slits  540  can extend through the full thickness of the track (thickness as measured in the vertical direction in  FIG. 8 ). Additionally, the slits can extend from one side of the track to extend across the full the width of one of the prongs  516 , and the slits can continue through at least a portion of the floor  512 . Each of the slits  540  can extend through the full thickness of the track body  520 , and each of the slits  540  can extend more than halfway, but not fully across the width of the track. The spacing  542  ( FIG. 6 ) between slits  540  on the same side of the carrier body can be between about 0.1 inch and about 0.6 inch in carrier body portion  520 A. The staggered arrangement of slits  540  provide the advantage that the carrier body portion  520 A does not have a longitudinally continuous load path for carrying tensile loads or bending loads. 
       FIGS. 9-13  illustrate a feeding tube  600  which can be used with the track  300  and the carrier  500 . Feeding tube  600  can have a proximal end  602  and a distal end  604 . Feeding tube  600  can include a feeding tube body  610  having a nutrient passageway  620  for passing nutrients, and a feature  660  adapted to provide releasable engagement of the feeding tube  600  with another member. For instance, the feature  660  can include a rail for providing sliding engagement of the feeding tube with a track or the carrier  500 . 
     The passageway  620  can extend from proximal end  602  to an exit port  622  through which nutrients exit the passageway  620  and enter the patient&#39;s GI tract. The portion of the feeding tube  600  extending distally of exit port  622  can be inclined with respect to the longitudinal axis of the passageway  620 , as shown in  FIGS. 10 and 13 , and with exit port  622  having a generally tapered, elongated configuration. Accordingly, as shown in  FIGS. 10 and 13 , the passageway  620  can be generally parallel with respect to the longitudinal axis of the feeding tube  610 , and the passageway  620  does not bend or curve to communicate with the exit port  622 , except to the extend the tube  610  itself is bent. Having the passageway  620  run substantially straight to exit port  622  and the distal tip portion of the feeding tube inclined with respect to the passageway  620  can provide the advantage that passageway  620  can be easily cleaned, such as by running a wire from the proximal entrance of the feeding tube through the passageway  620  and out through exit port  622 . 
     Referring to  FIG. 12 , feeding tube  600  can include one or more suction ports positioned either proximally or distally of exit port  622 . Suction ports can be used to hold the distal end of the tube  600  in a desired position within the body once the tube  600  is placed, and prevent migration of the feeding tube  600  during feeding. In  FIG. 10 , a suction port  680  is shown positioned distally of exit port  622 . Suction port  680  can include a plurality of radially inwardly extending tabs  682  which can engage and hold tissue when tissue is drawn into the tube  600  by vacuum applied to suction port  680 . The tabs  682  can be formed by cutting or slitting the outer wall of tube body  610  to create the tabs  682 , or tabs  682  can be provided in a separate member, such as a metallic or non metallic insert that is formed to include tabs  682 , and which is positioned in an aperture in the wall of tube body  610 . Vacuum can be communicated to suction port  680  through a vacuum passageway (not shown) which communicates with, or extends separately of, nutrient passagaeway  620 . Weights  690  can be disposed in the distal end of tube  600  to assist in maneuvering and positioning the feeding tube  600 . 
     The feature  660  can extend along at least a portion of the length of feeding tube  600 . In  FIG. 10 , the feature  660  is shown extending along some, but not all of the length of the feeding tube  600 . Feature  660  can extend from a proximal end  662  of feature  660  to a distal end  664 . The proximal end  662  of the feature  660  can be spaced from the proximal end of the feeding tube  600  by a distance L, so that the portion of the feeding tube  600  which extends through the throat and/or nose of the patient when the feeding tube  600  is in place does not irritate the patient or interfere with feeding. The distance L can be between about six inches and about 24 inches, and in one embodiment is about 18 inches. 
     The feature  660  can be integrally formed with the tube body  610  (such as by molding or extruding). Alternatively, the feature  660  could be manufactured separately from tube body  610 , and subsequently attached to body  610 , such as by use of any suitable bonding or joining method. Feature  660  can be sized and shaped to permit the feeding tube  600  to releasably engage another member, such as track  300  or carrier  500 , such as by sliding engagement. In  FIG. 9 , the feeding tube  600  is shown slidably supported on carrier  500 . The feature  660  can comprise a rail  666  and a web  668 , with web  668  extending generally radially from tube body  610  to support rail  666  in spaced relationship from tube body  610 . In  FIG. 9 , rail  666  is positioned in channel  522 , with web  668  extending through the throat of channel  522 . Without being limited by theory, it is believed that slidably supporting the feeding tube  600  on carrier  500  while slidably supporting the carrier  500  on track  300  is advantageous in providing for smooth, relatively low friction positioning of feeding tube  600  within the patient. Alternatively, feeding tube  600  could be slidably supported directly on track  300 , such as by having rail  666  engage track  300  directly. For example, if desired, the track  300  could be coated with Teflon or any other suitable low friction coating. 
       FIG. 11  illustrates the proximal end  662  of feature  660 . A tapered surface  672  can be provided at proximal end  662  to prevent tissue from being caught or pinched as web  668  and rail  666  slide with respect to the channel  522  of carrier  500 . The proximal end of rail  666  can be formed, such as by tapering, to provide contact surfaces  674  disposed at the proximal end of rail  666 , on either side of web  668 . Contact surfaces  674  can be angled with respect to the longitudinal axis of the feeding tube  600  (in  FIG. 11  the surfaces  674  are inclined to extend outwardly as they extend distally). The contact surfaces  672  provide a surface at which a force can be provided to feature  660  in order to push the feeding tube  600  distally along carrier  500 . The orientation of the contact surfaces  672  can be selected with respect to the longitudinal axis of the feeding tube  600  such that the force applied to push the tube  600  distally on carrier  500  does not tend to push the feature  660  out of the channel  522  in carrier  500 . 
     If desired, the carrier  500  and the feeding tube  600  with feature  660  can be packaged together. For instance, the carrier  500  and feeding tube  600  could be packaged together, with the feeding tube  600  pre-assembled on the carrier  500  such as by sliding engagement of the tube with the carrier  500 . The assembly of the carrier  500  with the tube  600  supported along the length of the carrier can be unpackaged (such as from sterile packaging) at the point of use, and the assembly of the carrier  500  and tube  600  could be advanced along the track  300 . 
       FIG. 14  is a side view illustration of the distal portion of a feeding tube positioning member  700 . Member  700  can be used to push the feeding tube distally along the carrier  500  and/or to maintain the feed tube  600  in a desired position in the GI tract as the endoscope is withdrawn from the patient.  FIG. 15  is an enlarged illustration of the distal end of the member  700 .  FIG. 16  illustrates the member  700  positioned to maintain the feeding tube  600  in a desired position, and  FIG. 17  is an enlarged bottom view of the engagement of the distal end of member  700  with proximal end  662  of feature  660  on feeding tube  600 . In one embodiment, the length of member  700  can be at least about 36 inches so that the member  700  can extend from a point outside the patient to engage the contact surface  672  on the feeding tube  600  when the feeding tube is positioned in a desired location in the patient&#39;s GI tract. 
     Referring to  FIGS. 14 and 15 , the member  700  can have a structure similar to that of the carrier  500 . Alternatively, member  700  can have a different cross-sectional shape. The member  700  can include a body portion  710 , which may include slits  740  to provide flexibility. The member  700  can include a rail  766  and a web  768 , with web  768  extending from body  710  to support rail  766  in spaced relationship body  710 . Rail  766  can be sized and shaped for sliding movement within channel  520  of carrier  500 . 
     As shown in  FIG. 15 , the distal end  702  of member  700  can have a tapered surface  772  on body portion  710 . The distal end of rail  766  can be formed to have a V shaped notch with two surfaces  774  being provided to engage surfaces  674  on the feeding tube  600 . The surfaces  774  are positioned distally of the surface  772  and are sized and shaped to contact surfaces  674  on feeding tube  600  such that the rail  766  of member  700  can be employed to exert a force on rail  666  of the feeding tube which force is generally parallel to the rail  766  and rail  666 . Such surfaces can provide a desired longitudinally directed force without a radial force component, or other force component that might urge feeding tube  600  out of the carrier  500  in an undesired manner. 
     The endoscope with sheath  200  and track  300  can be positioned in a patient such that the distal end of the endoscope is positioned at a desired position within the GI tract for feeding tube placement. The feeding tube  600  can be positioned on carrier  500  by sliding the feeding tube onto carrier  500  outside of the patient (or the feeding tube  600  and carrier  500  can be provided in a pre-packaged assembly), and the carrier  500  and feeding tube  600  can then be advanced together along track  300  to a desired position in the GI tract, such as with the distal portion of the feeding tube positioned in the stomach or small intestine. The tab  536  on carrier  500  can be viewed through the endoscope optics once the tab  536  extends through the endcap  400 , thereby providing visual indication that the carrier and feeding tube have reached the desired position. Alternatively, the carrier  500  could be advanced to along the track  300 , and then the feeding tube  600  could be advanced along the carrier  500  to the desire position. 
     Once distal end of the feeding tube  600  has been advanced to a desired position in the body, the endoscope, sheath  200 , track  200 , and carrier  500  can be removed from the GI tract leaving the feeding tube in place. In order to prevent the feeding tube from “backing out” or otherwise moving in a proximal direction as the other components are removed from the body, feeding tube positioning member  700  can be employed to maintain the position of the feeding tube during removal of the other components. After positioning of the feeding tube  600  (and prior to removal of the endoscope, sheath  200 , track  300 , and carrier  500 ), the member  700  can be inserted in carrier  500  (with rail  766  positioned in channel  520  of carrier  500  so that member  700  slidably engages carrier  500 ) and the member  700  can be advanced distally along the carrier  500  until the distal end of the member  700  is adjacent the proximal end  662  of the rail  666  on feeding tube  600 . As the endoscope, sheath  200 , track  300 , and carrier  500  are withdrawn in a proximal direction from the patient&#39;s body, the member  700  can be held in place (such as by the hands of the physician, a physicians assistance, or a fixture) to maintain the member  700  stationary with respect to the endoscope, sheath, track, and carrier, and exerting a force on the feeding tube rail  666  at the interface of surfaces  774  and surfaces  674 , thereby “blocking” the feeding tube  600  from backing up proximal during withdrawal of the endoscope and other components. 
       FIGS. 18-24  illustrate steps which may be employed in a method for positioning a feeding tube according to one embodiment of the present invention. The endoscope can be inserted into the sheath  200 , with the endcap  400  positioned at a distal end of the sheath  200 , the handle  100  positioned at a proximal end of the sheath  200 , and with the track  300  extending along the sheath  200  from the endcap  400  to the handle  100 . As used herein after, the term “sheath assembly” shall refer to the assembly of the sheath  200 , handle  100 , endcap  400 , and track  300 . After inserting the endoscope into the sheath assembly outside of the patient, the sheath assembly and endoscope can be inserted into a naturally occurring body opening, such as the mouth, and the sheath assembly with endoscope can be advanced so that the distal end of the endoscope and the endcap  400  are positioned at a desired location, such as the small intestine.  FIG. 18  illustrates the sheath assembly positioned in the GI tract of a patient, with the track  300  extending from a position outside the body to a position in the small intestine. 
     The feeding tube  600  can be positioned on the carrier  500  outside of the patients body, such as by sliding the feeding tube rail  666  in the channel  520  of the carrier  500  until the feeding tube  600  is positioned along the length of the carrier  500 , with the distal end of the feeding tube positioned at or adjacent to the distal end of the carrier  500 . Referring to  FIG. 19 , the carrier  500  and feeding tube  600  can then be advanced (such as by hand in the direction of arrow  2 ) together along track  300 , with the carrier and feeding tube being advanced from a position outside the patient to a position where the distal end of the feeding tube is positioned at a desired location (the small intestine in  FIG. 19 ). The length of feeding tube  600  can, in one embodiment, be at least about 140 cm long, and the distal end of the feeding tube can be positioned between about 130 to about 140 cm from the patients incisors. By way of non-limiting example, a 140 cm length 10 Fr Dobb-Hoff-type feeding tube (available from Viasys Healthcare, Inc.) can be modified to have the rail  666  feature, such as by bonding or otherwise attaching a web and rail to the tube. A pediatric colonoscope, such as an Olympus model PCF100 pediatric colonoscope can be employed with the sheath assembly. 
     Referring to  FIG. 20 , once, the feeding tube  600  is in the desired position, the member  700  can be advanced distally (such as by hand in the direction of arrow  4 ) along the track  300  until the distal end  702  of the member  700  makes contact with the proximal end of the rail  666  of feeding tube  600 . Then, as the member  700  is held stationary with respect to the patient&#39;s body and to the sheath assembly, the sheath assembly (with endoscope), and the carrier  500  can be withdrawn proximally from the body, in the direction indicated by arrow  6 . Any tendency of the feeding tube  600  to move proximally during withdrawal of the endoscope, sheath assembly, and carrier  500  is prevented by abutting engagement of the surfaces  774  on member  700  with the surfaces  674  on the feeding tube rail  666 . Accordingly, the feeding tube  600  is maintained in position by member  700  as the endoscope, the sheath assembly, and the carrier  500  are withdrawn from the body. 
       FIG. 21  illustrates the feeding tube in place in the patient&#39;s GI tract after removal of the endoscope, sheath assembly, and carrier  500 . In  FIG. 21 , the feeding tube  600  extends from the feeding tube proximal end  602  (positioned outside the patient&#39;s body) to the feeding tube distal end  604  (positioned in the small intestine), with the feeding tube  600  extending through the mouth, the esophagus, the stomach, and into the small intestine. 
     If desired, the feeding tube can be used in the position shown in  FIG. 21 . However, it may generally be desirable to have the proximal end of the feeding tube extending from the nose.  FIG. 22  illustrates use of a transfer tube  12  which may be inserted to extend from the mouth and the nose. The end of the transfer tube extending from the mouth can be coupled to the proximal end  602  of the feeding tube, as shown in  FIG. 23 . The end of the transfer tube  12  extending from the nose can then be pulled so that the proximal end  602  of the feeding tube is redirected to extend from the nose, as shown in  FIG. 24 . A suitable fitting  14  can then be attached to the proximal end  602  of the feeding tube, as shown in  FIG. 24 . 
       FIGS. 25-30  illustrate an alternative method for positioning a feeding tube within a patient for providing feeding access through an incision in the patient&#39;s abdominal wall.  FIGS. 25-30  illustrate a method of placing a feeding tube in the stomach as an alternative to standard PEG procedures. Referring first to  FIG. 25 , the endoscope disposed within the sheath assembly comprising the handle  100 , sheath  200  and endcap  400  can be advanced through the mouth to position the distal end of the endoscope and the endcap  400  within the stomach of the patient. A light source (such as a light source associated with the distal end of the endoscope) can be employed from within the stomach to transilluminate the abdominal wall, so that the position of the endoscope within the stomach can be observed from outside the patient. A small, percutaneous incision can be made through the abdominal wall, and a needle  22 /cannula  24 , such as a  14  gauge needle  22 /cannula  24  can be inserted through the incision so that the distal tip of the needle and the distal end of the cannula can be positioned within the stomach. 
     Referring to  FIG. 26 , the needle  22  can be withdrawn, leaving the cannula  24  to provide an access channel extending from inside the stomach to a point outside the patient. A looped guide wire  32  can be passed through the cannula, and the endoscope and sheath assembly can be directed to extend through the loop provided by the guide wire  32 . 
     Referring to  FIG. 27 , a relatively short feeding tube  800  is illustrated, the feeding tube having a length substantially less than the length of the track  300 . Feeding tube  800  in this embodiment can have a length of less than about  3  feet. The feeding tube  800  can be a commercially available PEG type feeding tube modified to have a feature, such as a rail (not shown), for permitting the feeding tube  800  to slidably engage the track  300  and/or carrier  500 . For instance, the feeding tube  800  can be formed by attaching a web and rail to a commercially available PEG feeding tube, such as by bonding or otherwise attaching the web and rail to the feeding tube (alternatively, the feeding tube  800  could be formed by extruding or otherwise forming a feeding tube to have an integral web and rail feature). One suitable commercially available PEG type feeding tube from which feeding tube  800  can be constructed is available from Viasys Healthcare of Wheeling, Ill. as marketed in a Corflo-Max brand PEG kit for use with a Push Technique or Pull Technique. The feeding tube  800  can include a sealing bumper or bolster  810  and a tapered dilating tip  820 . 
     Referring to  FIG. 27 , with the sheath assembly extending through the loop provided by guide wire  32 , the feeding tube  800  can advanced distally along the sheath assembly and into the stomach. The feeding tube  800  can be positioned on track  300  and advanced distally along track  300  to the stomach by using member  700  as a pushing element. Alternatively, the feeding tube can be disposed on carrier  500 , and the carrier  500  with feeding tube  800  can be advanced along track  300  to the stomach. 
     Referring to  FIG. 28 , the feeding tube  800  can be pushed off the distal end of the sheath assembly using a member, such as a member  700  described above. As the feeding tube  800  is pushed off the sheath assembly, a suture  830  (or other suitable flexible wire or tether) that extends from the tip  820  can be grasped with the guidewire  32  so that the suture  830  can be pulled through cannula  24 . 
     Referring to  FIG. 29 , the suture  830  can be pulled (such as with forceps or a hemostat) so that tip  820  extends through the percutaneous incision through the abdominal wall and such that the sealing bumper  810  is positioned against the inside surface of gastric wall (inside surface of the stomach). 
     Referring to  FIG. 30 , the sheath assembly can be removed from the patient, and an external seal  840  can be advanced over the feeding tube  800  to fit against the patients skin adjacent the incision. The feeding tube  800  can be cut to sever the tip  820  from the feeding tube, and a fitting  850  can be positioned on the end of the feeding tube external of the patient. In the procedure illustrated in  FIGS. 25-30 , a feeding tube is introduced into the patient through a naturally occurring orifice and pushed distally along an endoscope after the endoscope has been positioned in the stomach. The feeding tube is then pulled through an incision to provide a feeding access channel that extends through an incision to the patient&#39;s GI tract. 
       FIGS. 31-37  illustrate steps which can be employed in a method for positioning a feeding tube according to another embodiment of the present invention.  FIGS. 25-30  illustrate a method of placing a feeding tube in the small intestine as an alternative to standard JET-PEG type procedures. 
     Referring first to  FIG. 31 , the endoscope  1000  disposed within the sheath assembly comprising the handle  100 , sheath  200  and endcap  400  can be advanced through the mouth to position the distal end of the endoscope and the endcap  400  within the stomach of the patient. A light source (such as a light source associated with the distal end of the endoscope) can be employed from within the stomach to transilluminate the abdominal wall, so that the position of the endoscope within the stomach can be observed from outside the patient. A small, percutaneous incision can be made through the abdominal wall, and a needle  22 /cannula  24 , such as a  14  gauge needle  22 /cannula  24  can be inserted through the incision so that the distal tip of the needle and the distal end of the cannula can be positioned within the stomach. 
     Referring to  FIG. 32 , the needle  22  can be withdrawn, leaving the cannula  24  to provide an access channel extending from inside the stomach to a point outside the patient. A looped guide wire  32  can be passed through the cannula, and the endoscope and sheath assembly can be directed to extend through the loop provided by the guide wire  32 . The endoscope and sheath assembly can be advanced distally from the stomach into the small intestine, as shown in  FIG. 32 . 
     Referring to  FIG. 33 , a feeding tube  900  can be advanced along the length of the sheath assembly such that the feeding tube  900  passes through the loop provided by guidewire  32 . The feeding tube  900  shown in  FIG. 3  can include a distal portion  904  having a construction like that of the feeding tube  600  described above, and a proximal portion  906  having a construction similar to that of the feeding tube  800  described above. The proximal portion  906  can include a tapered dilating tip  920  and a bumper or bolster  910 . The proximal portion  906  can be constructed using a PEG feeding tube of the type provided in Corflo-Max brand PEG Kits for Pull Technique or Push Technique, which kits are available from Viasys Healthcare of Wheeling, Ill. 
     The opening through which food is delivered to the GI tract can be located in the distal portion  904 . The feeding tube  900  can include a feature, such as a rail (such as the type shown in  FIGS. 10 ,  11 , and  13 ) on one or both of the portions  904  and  906  such that feeding tube can slidably engage the track  300  and/or the carrier  500 . In one embodiment, the feeding tube  900  is positioned on the carrier  500  outside of the patient&#39;s body, and the feeding tube  900  and carrier are advanced together along track  300 . The positioning member  700  can be advanced along carrier  500  behind feeding tube  900 . If desired, the positioning member  700  can include a grasping clip  715  which can clip onto or otherwise be fastened to member  700  to assist in grasping and pushing the member  700  along carrier  500 . 
     Referring to  FIG. 34 , with the positioning member  700  held in position, the endoscope and sheath assembly can be retracted proximally from the stomach, such that the feeding tube  900  is pushed off the end of the sheath assembly by positioning member  700  as the endoscope and sheath assembly are retracted. A length of suture  930  extending from the tip  920  can be grasped using the looped guide wire  32 . 
     Referring to  FIG. 35 , the suture  930  and tip  920  can be pulled through the incision until bumper  910  is positioned against the inside surface of the stomach, with the portion  904  of the feeding tube including the port through which food is provided being positioned in the small intestine (such as the jejunum). Referring to  FIG. 36  an external seal  940  can be advanced over the feeding tube  900  to fit against the patients skin adjacent the incision. The feeding tube  900  can be cut to sever the tip  920  from the feeding tube, along with any unneeded length of the tube, and a fitting  950  can be positioned on the end of the feeding tube external of the patient. In  FIG. 37 , the endoscope and sheath assembly are shown removed from the patient&#39;s body, and the feeding tube  900  is shown positioned with the distal portion  904  disposed in the small intestine, and with the feeding tube  900  extending from the small intestine through the stomach to pass through an incision through the stomach and through the patient&#39;s abdominal wall and skin. 
     In the procedure illustrated in  FIGS. 31-37 , a feeding tube is introduced into the patient through a naturally occurring orifice and pushed distally along an endoscope after the endoscope has been positioned in the stomach. The feeding tube is then pulled through an incision to provide a feeding access channel that extends through a percutaneous incision into the patient&#39;s GI tract (eg. small intestine). 
     In some embodiments it may be desirable to include a cover or tunnel, such as around the track  300 , carrier  500 , and/or the feeding tube, to reduce the risk of contamination of the feeding tube as it is advanced to a desired location, such as for instance from contamination by oral material, such as oral flora. The cover or tunnel can be formed of a thin flexible material (such as for instance a cellophane material or the material from which sheath  200  is formed), and can extend at least partially along the length of the track, carrier and/or feeding tube. For instance, an assembly of the carrier, feeding tube, and a flexible cover can be provided as a pre-packaged assembly. The carrier, feeding tube, and flexible cover can then be advanced along the track. If desired, the flexible cover can be disposed on the carrier such that the cover and carrier are withdrawn, leaving the feeding tube in place. In another embodiment, the sheath  200  can be formed to include a tunnel extending over and along the track, such that the carrier and feeding tube can be advanced through the tunnel. Alternatively, the track could be disposed on the inside surface of a sheath, or on the surface of the endoscope, such that the feeding tube is advanced within the sheath. Above referenced U.S. Ser. No. 10/440,957 (published as US 2004/0230095) discloses a sheath and accessories advanced along an inside surface of a sheath, such as in the embodiment of  FIG. 6  of US 2004/0230095. Such an arrangement can be employed, with the feeding tube advanced within the sheath. 
       FIGS. 38-42  illustrate a method for positioning and endcap  400  (such as an elastomeric endcap  400 ) and sheath  200  on an endoscope  1000  prior to inserting the endoscope on the sheath assembly into the patient. In some applications, it may be difficult to manually load an endoscope into a sheath having an endcap, such as by gripping the components by hand. For instance, it may be difficult to grip the endoscope through the sheath and apply the appropriate force to urge the endcap to fit over the distal end of the endoscope. Additionally, it may be desirable to maintain a certain angular “o&#39;clock” orientation of the endcap with respect to the endoscope. In the course of applying the force to urge the endcap onto the endoscope, the desired o&#39;clock orientation may be inadvertently lost, requiring re-intallation. The method and components illustrated in  FIGS. 38-42  can be employed to assist in proper installation of an endcap (and associated sheath and track) onto an endoscope. Additionally, the method and components can be employed to intall an endcap on an endoscope even if no sheath and or track is employed. 
     Referring to  FIG. 38 , an endcap loading element is shown in the form of a nose cone  2100 . The nose cone  2100  can be disposable, and can be formed of a lightweight material, such as a polymeric material. The nose cone  2100  can include a body portion  2110  and a plurality of flexible prongs  2120  (six prongs shown in  FIG. 38 ). The distal end  2102  of the body portion  2110  can be rounded or tapered. The body portion  2110  can include a through hole  2112  which extends through the width of body portion  2110  in a direction transverse to the longitudinal axis of the body portion  2110 . The body portion  2110  and the prongs  2120  can be sized and shaped to pass through the central bore opening  420  of endcap  400 . 
     The body portion  2110  can include a plurality of radial splines  2114  which extend along the length of body portion  2110 . Each spline  2114  can be associated with a rounded or sloped prong shoulder  2118 . Each prong shoulder  2118  can be associated with a flexible prong  2120 . Each flexible prong  2120  can extend proximally from a prong shoulder  2118  to a proximal prong end  2122 . Each rounded prong shoulder  2118  can extending radially outward from its associated spline  2114  on the body portion  2110  to the flexible prong  2120  associated with that prong shoulder. 
     The radially outward surfaces of the splines  2114  can define a first diameter of the nose cone  2100 , and the radially outward surfaces of the prongs  2120  can define a second diameter of the nose cone, with the second diameter being greater than the first diameter. The radially outer surface of each rounded prong shoulder  2118  can be shaped to provide a smooth radial transition from each spline to its associated prong. Accordingly, the rounded prong shoulders  2118 , together, provide a smooth radial transition from the first diameter to the second diameter. The radially inward facing surfaces of the flexible prongs  2120  can be spaced apart (either by being formed in that fashion, or due to an applied force) to receive the distal end of the endoscope  1000 . 
     The splines  2114 , rounded prong shoulders  2118 , and the prongs  2120  can be circumferentially spaced apart at generally equal angular intervals (e.g. for six splines, six prong shoulders, and six prongs, each associated spline, prong shoulder, flexible prong could be spaced at 60 degree intervals about the circumference of the body portion  2110 ). 
     Each prong  2120  can have a slot  2124  formed in the outwardly facing surface, as shown in  FIG. 38A  and  FIG. 40A . Together, the slots  2124  in the prongs  2120  provide a circumferentially interrupted groove in which an expandable ring, such as a silicone O-ring or Teflon O-ring  2160  can be seated. The radial thickness  2123  of the prongs  2120  illustrated in  FIG. 38A  can be sized to take into account various factors, such as the inner diameter and material of the endcap, the outer diameter of the distal end of the endoscope  1000 , and the number of prongs  2120  on nose cone  2100 , such that when prongs  2120  are disposed between the outer surface of the distal end of the endoscope, and the inner surface of the endcap, the radially inner surface of the endcap is spaced from the outer surface of the endoscope. One suitable thickness  2123  when six prongs  2120  are employed is about 0.032 inch. 
     Prior to seating the O-ring  2160  in the slots  2124 , the distal end of the endoscope  1000  can be inserted between the prongs  2120 . The O-ring  2160  can then be slid over body  2110  of nose cone  2100  and up over the rounded prong shoulders  2118 . The O-ring can be stretched over the shoulders  2118  and be seated in the slots  2124  in prongs  2120 . The O-ring can thereby provide a radially inward compressive force on the prongs  2120 , urging the radially inwardly facing surfaces of the prongs  2120  into engagement with the outer surface of the distal end of the endoscope  1000 . 
     With the nose cone  2100  positioned on the distal end of the endoscope  1000  the endoscope  1000  is loaded onto the sheath assembly (comprising the handle  100 , sheath  200 , track  300 , and endcap  400 ). The endoscope is loaded onto the sheath assembly such that the body portion  2110  of nose cone  2100  extends distally from the endcap  400 , as shown in  FIG. 39 , and such that the proximal face of the endcap  400  abuts against prong shoulders. The O-ring  2160  and two proximal prong ends  2122  are shown in phantom in  FIG. 39 , as the O-ring and prong ends would be inside the sheath (but can be visible when sheath  200  is made of a substantially transparent film material). 
     Referring now to  FIG. 40  and  FIG. 40A , a handle  2200  is shown with a pair of outwardling extending arms  2204  extending from a central hub  2208 . The hub  2208  includes a grooved through bore  2210 . The through bore  2210  has grooves sized and shaped to permit the handle  2200  to slide longitudinally along the splines  2114  of body portion  2110  on nose cone  2100 . The engagement of the splines  2114  with the grooved bore  2210  prevents rotation of the handle  2200  with respect to the nose cone  2100  and the endcap  400 . While rotation of the handle  2200  with respect to the nose cone  2100  could be permitted in an alternative embodiment that does not employ splines and grooves, it can be advantageous to prevent rotation of the handle  2200  with respect to the nose cone  2100 . For instance, it may be desireable to load the endcap  400  and track  300  onto the endoscope in such a way to maintain a desired o&#39;clock orientation of the track  300  with respect to features such as optics and/or working channels in the distal end of the endoscope. Maintaining the handle  2200  rotationally fixed with respect to the nose cone  2100  can aid in avoiding angular misalignment of the track  300  with respect to the distal end of the endoscope  1000 . 
       FIG. 40A  illustrates the nose cone  2100  extending into the bore  2210  from the proximal side of the handle  2200 . The proximal side of handle  2200  can include one or more surfaces for providing a pressing force against distal surface  412  of endcap  400 . In  FIG. 40A , the handle  2200  is shown having multiple generally wedge shaped extensions  2700  extending proximally from handle  2200 . In  FIG. 40A , six extensions  2700  are provided, one for each groove in the through bore  2210 . The extensions  2700  can be separated by a distance substantially equal to the width of the grooves in the through bore  2210 . The extensions  2700  each have a proximally facing surface  2710 . Together, the surfaces  2710  can engage the distal surface  412  of endcap  400  as handle  2200  is advanced proximally along nose cone  2100 . Providing separate, spaced apart surfaces  2710  can be beneficial in preventing the material of endcap  400  from being pinched between the nose cone  2100  and the handle  2200  as the handle  2200  provides a pushing force against endcap  400  and prongs  2120  provide a pulling force on the distal end of the endoscope. 
     Referring to  FIG. 41 , a pull ring  2300  is shown attached to a distal end of the nose cone  2100 , such as with a pin  2308  which extends through a pull ring collar  2304  and into through bore  2112  in nose cone  2100 . The combination of the pull ring  2300  mounted on the distal end of the nose cone  2100  and the handle  2200  slidably supported on the nose cone  2100  via the spline and groove arrangement permits a user to provide a distal pulling (tensile) force on the endoscope  1000  through the endcap  400  via the nose cone  2100 , while at the same time exerting a proximal pushing (compressive) force on the distal face of the endcap  400  via the surfaces  2710  of handle  2200 . 
     Referring to  FIG. 42 , the application of such forces is illustrated schematically by arrows  2250  and  2350 . By pulling on the pull ring  2300  in the direction indicated by arrow  2350  while pushing on the handle  2200  in the direction indicated by arrows  2250 , the endcap  400  is pushed onto the distal end of the endoscope  1000  and the O-ring is forced off the prongs  2120 , such that the prongs  2120  can disengage from the distal end of the endoscope  1000  and be pulled through the through bore  420  of the endcap  400 .  0 -ring  2160  can remain positioned about the endoscope proximal of the endcap  400 . 
     In the installation embodiment shown in  FIGS. 38-42 , a distal pulling force is applied to the outside surface of the endoscope  1000  with flexible prongs  2120  as a proximal pushing force is provided by handle  2200  against the distal face of the endcap  400 .  FIGS. 43-47  illustrate an alternative apparatus and method for use in positioning an endcap on an endoscope, which can be employed to provide a pulling force at an internal surface of an endoscope, such as an internal surface of a working channel of an endoscope, as a pushing force is applied to the endcap. The sheath and track are omitted from the Figures for clarity, with it being understood that the apparatus and method illustrated in  FIGS. 43-47  can be used to position an endcap on the distal end of an endoscope, including in applications where a sheath and/or track is not employed. 
       FIG. 43  is a schematic isometric view of the loading apparatus  3000 , and  FIG. 44  is a partial cross-sectional illustration of the apparatus  3000 . In  FIGS. 43 and 44 , the endcap  400  is shown for illustration purposes, with it being understood that the endcap  400  is not part of the apparatus  3000 .  FIGS. 45 ,  46 , and  47  illustrate steps in employing the apparatus  3000  to load an endcap  400  on and endoscope, with the endoscope and endcap being illustrated to be generally transparent for purposes of illustration and clarity (though endcap  400  and endoscope could be formed of generally transparent materials if desired). 
     Apparatus  3000  includes a body section  3100 , a rotation section  3200 , and translating section  3300 , and a ring  3400 . As shown in  FIGS. 45 and 46 , the apparatus  3000  can include one or more expandable members, such as resilient cylinders  3500 , which can engage an internal surface of the endoscope, such as by being positioned within a working channel of the endoscope. Cylinders  3500  can be formed of any suitable material, such as rubber or synthetic elastomeric materials, which expands radially when compressed axially. Alternatively, other types of expandable members could be employed, such as members which expand by inflation. 
     Referring to  FIG. 46 , the cylinders  3500  can be expanded to engage the inside surface of the working channel. Expansion of the rubber cylinders can be provided, in part, in connection with the rotation of rotation section  3200 , as described more fully below. 
     Referring to  FIG. 47 , with the cylinders  3500  expanded within the working channel of the endoscope to compressively engage the radially inner surface of the working channel, the translating section  3300  can be drawn distally relative to body section  3100  (as indicated by arrows  3302  in  FIG. 47 ). As shown in the Figures, body section  3100  can include a recess  3120  having a proximally facing surface  3122  for engaging the distal surface  412  of endcap  400 . As translating section  3300  is drawn distally relative to body section  3100 , the cylinders  3500  can be retracted distally relative to body section  3100 . Accordingly, the combination of the pulling force provided on the endoscope by the cylinders  3500  being pulled distally while engaging the inside surface of the working channel, and the complementary reactive pushing force exerted on the distal surface  412  of endcap  400  by surface  3122 , serves to press the endcap  400  onto the distal end of the endoscope. Accordingly, the apparatus  3000  can be used to install the endcap  400  on the distal end of the endoscope without holding or otherwise contacting the exterior surface of the endoscope or the sheath (if a sheath is employed). 
     The components and operation of the apparatus  3000  will now be described in more detail with reference to  FIGS. 43-47 , as well as cross-sectional illustrations  48  and  49 . Body portion  3100  can include an outer surface provided by two body halves  3106  and  3108 . Body halves can be joined together in any suitable manner, such as with screw type fasteners, rivets, with adhesive, and the like. 
     The translating section  3300  can be disposed at least partially within the body portion  3100 , and can include a hub  3316  and outwardly extending ring grips  3318 . The ring grips  3318  can extend outwardly from hub  3316  through slots provided between body portion shell halves  3106  and  3108 . 
     Referring to  FIG. 44  and  FIG. 48 , rotating section  3200  can be supported at an end of body portion  3100  such that rotating section  3200  is rotatable with respect to body portion  3100  and such that rotating section is rotatable with respect to translating section  3100 . As shown in  FIG. 48 , rotating section  3200  can have end  3202  received within a recess  3105  provided by body halves  3106  and  3108 . End  3202  can include a ring  3204  formed on an outer surface of end  3202 . The ring  3204  is received in a groove  3107 , which can be formed on an inside surfaces of body halves  3106  and  3108 . The mating of ring  3204  in groove  3107  permits section  3200  to rotate with respect to body section  3100 , while preventing translation of section  3200  with respect to body section  3100 . 
     Rotating section  3200  can include a collar  3208  which can be gripped by fingers to rotate section  3200 . Ring  3400  can be supported at an end of rotating section  3200  such that Ring  3400  can rotate freely about the longitudinal axis of the rotating section  3200  independently of the position of rotating section  3200 . Accordingly, the ring  3400  can be aligned to have the same planar orientation as that of ring grips  3318  on translating section  3300 , regardless of how rotating section  3200  is rotated. 
       FIG. 48  provides an enlarged schematic cross-sectional illustration of portions of the translating section  3300  and the rotating section  3200 , and  FIG. 49  provides an enlarged schematic cross-sectional illustration of portions of the apparatus which are employed to engage the endcap or endoscope. The translating section  3300  can have a central bore  3342  extending the length of the translating section. The central bore  3342  is shown including an enlarged bore section  3344  extending along the length of hub  3316 . A shaft  3350  extends through central bore  3342 , and sized with respect to bore  3342  and supported in bore  3342  to rotate freely within bore  3342 . The shaft  3350  can extend from a first end  3352 , to a second end  3354 . Second end  3354  can have an enlarged diameter relative to the remaining length of the shaft  3350 , so that the second end  3354  can be employed to compress the cylinders  3350 . 
     Referring to  FIG. 48 , an internally threaded member  3360  is disposed at an end of the hub  3316 . The internally threaded member  3360  can be in the form of a nut having an internally threaded through hole that is generally coaxially aligned with respect to central bore  3342  and enlarged bore section  3344 . The internally threaded member  3360  is fixed with respect to translating section  3300 . 
     Rotating section  3200  can include a longitudinally extending internal channel  3242  which is generally coaxially aligned with respect to bore  3342 . An externally threaded member  3260  is disposed to slide in bore  3242 . The member  3260  can be in the form of a screw having a non-circular head  3262 , a longitudinally extended external threaded portion  3264 , and a longidtudinally extending through bore  3266 . Through bore  3266  extends the length of the screw  3260 , and can have an internal diameter sized to receive shaft  3350  therethrough. Through bore  3266  can be sized such that shaft  3350  may rotate freely with respect to screw  3260 . 
     The head  3262  of screw  3260  can have the shape of a regular polygon. Bore  3242  in rotating section  3200  can have a non-circular cross-sectional shape similar to that of the head  3262  (e.g. hexagonal cross-section if head  3262  is hexagonal), so that screw  3260  can translate in bore  3242  relative to rotating section  3200 , but such that screw  3260  is constrained to rotate with rotating section  3200 . Alternatively, screw  3260  could have a head  3262  which includes a key or other feature for permitting sliding translation of screw  3260  within the bore  3242 , while ensuring that screw rotates with rotating section  3200 . 
     A shaft collar  3356  is disposed at or near shaft end  3352  of shaft  3350 . Shaft collar  3356  can be fixed to shaft  3350 , such as with a set screw, pin, adhesive, or any other suitable fastening means for fixing collar  3356  on shaft  3350 . Collar  3356  can be disposed in bore  3242 , and has an outer diameter sized to permit collar  3356  to freely translate and rotate with respect to rotating section  3200 . A surface  3358  of collar  3356  can abut or otherwise engage an end surface of screw head  3262 , as shown in  FIG. 48 . 
     Referring to  FIG. 49 , cylinders  3500  can be supported on a portion of the shaft  3350  which extends from bore  3342 . Cylinders  3500  can be supported on a portion of the shaft  3350  which extends outwardly from an end face  3302  of translating section  3300 . One cylinder  3500  can be disposed on shaft  3350  between shaft end  3354  and a spacer  3352 . Spacer  3352  is formed of a material which is relatively harder and less resilient than cylinders  3500 , and spacer  3352  can be in the form of a metallic washer. The second cylinder  3500  can be disposed on shaft  3350  between spacer  3352  and a pair of spacers  3354 . Spacers  3354  can be disposed on shaft  3350  between the second cylinder  3500  and end face  3302 , as shown in  FIG. 49 . 
     To employ the apparatus  3000  to load an endcap onto an endoscope, the apparatus  3000  is positioned with respect to the endcap and endoscope as shown in  FIG. 45 , with the translating section  3300  in a forward position with respect to the body section  3100 , with shaft end  3350  and cylinders  3500  disposed in the working channel of the endoscope; with the endface  3302  of translating section  3300  against the distal end face of the endoscope, and with surface  3122  of body section  3100  against the distal face of the endcap. Rotating section  3200  is then rotated (such as via collar  3208 ), which rotation causes screw  3260  to rotate within nut  3360 . As screw  3260  rotates, screw  3260  translates in a rearward direction in bore  3242 , in accordance with the pitch of the threads on screw  3260 . Rearward movement of screw  3260  pushes shaft collar  3356  rearward, which in turn causes the shaft  3350  and shaft end  3354  to move rearward relative to the translation section  3100 , thereby compressing the cylinders  3500  and causing the cylinders to expand radially and compressively engage the inside surface of the working channel of the endoscope. 
     Then, with the cylinders  3500  expanded in the working channel of the endoscope, the thumb can be inserted in ring  3400  and two fingers can be inserted in ring grips  3318 . The fingers in ring grips  3318  can exert a rearward force on translating section  3300  such that section  3300  is drawn rearward with respect to body section  3100 . Drawing the translating section  3300  rearward as shown in  FIG. 47  (in the direction of arrows  3302 ) also results in the shaft  3350  and cylinders  3500  moving rearward. Because the shaft  3350  and cylinders  3500  move rearward together with translating section  3300 , the cylinders are not expanded further. The rearward force on shaft  3350  (tensile force in shaft  3350 ) and cylinders  3500  (which engage the internal surface of the endoscope) exerts a rearward force on the endoscope (pulling force on endoscope), while surface  3122  on body section  3100  pushes on the distal face of the endcap. Accordingly, as the section  3300  is drawn rearward with respect to body section  3100 , a pulling force is exerted on an inner surface of the endosopce, while a pushing force is exerted on a distal face of the endcap, thereby urging the encap onto the distal end of the endoscope. 
     While the present invention has been illustrated by description of several embodiments, it is not the intention of the applicant to restrict or limit the spirit and scope of the appended claims to such detail. Numerous other variations, changes, and substitutions will occur to those skilled in the art without departing from the scope of the invention. For instance, the device and method of the present invention has been illustrated in relation to deployment of a feeding tube through the mouth and esophagus, but it will be understood the present invention has applicability to other portions of the body, and for instance, could be used to direct medical accessories into the body through other openings, including other naturally occurring openings in the body. Moreover, the structure of each element associated with the present invention can be alternatively described as a means for providing the function performed by the element. It will be understood that the foregoing description is provided by way of example, and that other modifications may occur to those skilled in the art without departing from the scope and spirit of the appended Claims.