Patent Publication Number: US-7909797-B2

Title: Medical catheter with stress riser at access port to reduce rupture force

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/844,133, filed Sep. 13, 2006, entitled “Medical Catheter with Stress Riser at Access Port to Reduce Rupture Force”, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to medical devices, more particularly catheters and the like that are introduced into the patient over a wire guide. 
     BACKGROUND OF THE INVENTION 
     Minimally invasive medicine, the practice of gaining access into a blood vessel, duct, or organ using a wire guide to facilitate the subsequent introduction or placement of catheters and other medical devices, has been evolving since the Seldinger technique was first popularized during the late 1950s and 1960s. A significant advance was gaining the ability to exchange medical devices over a single indwelling wire guide without requiring displacement of the wire in the process and loss of access to the site. This ‘over the wire’ (OTW) exchange technique requires an extra long guide wire so that control over the wire could be maintained at all times during the procedure. To accomplish this, the portion of the wire extending out of the patient must be at least as long as the device itself so that a proximal portion of the wire could be secured at all times maintain longitudinal positioning, typically by an assistant standing well behind the physician. For example, endoscopic catheters that are used to access the biliary system are typically 200 cm or more in length, requiring a wire guide of more than 400 cm (e.g., 480 cm) to be long enough to remain in the duct during the exchange. To remove the catheter over the wire, the physician and an assistant must carefully make a series of well-coordinated, one to one movements between the exchange wire and device. The assistant pushes the wire the same amount as the physician pulls back on the catheter until the device is completely outside of the patient and the physician gains control over the wire at the port of the scope. The assistant then pulls the device off of the wire such that a second device can be fed back over the wire and into the patient to perform a second operation, requiring the same push-pull technique in reverse. This procedure requires a well-trained assistant, who actually is responsible for the advancement of the wire, instead of the physician. In biliary ERCP, this lack of wire guide control can be a disadvantage when cannulating the ampullary orifice because the techniques used are typically highly dependent on good verbal communication between the physician and assistant, and the experience of the latter. 
     Although the ‘long wire’ or OTW technique still remains a commonly used method of exchanging devices in the biliary system, a technique was developed which allowed for a much shorter wire guide and more physician control over the wire. Variously known as the ‘rapid exchange,’ ‘monorail,’ or ‘short-wire’ technique, it differs from the OTW technique in that instead of the device being introduced over the length of the wire guide, the wire guide is coupled for only a portion of the length of the catheter device. The device is fed over the wire guide, which then exits the passageway or a coupling portion of the catheter at a point between the catheter&#39;s distal end and the proximal portion via a port or channel formed in the side of the catheter, typically located within the distal portion of the device. This allows the physician to have control of the proximal or external portion of the wire at all times as it exits the patient or scope and reduces the need for coordinating device movements with an assistant. When the coupled portion exits the patient (or endoscope in the case of gastroenterological or other endoscopic procedures), the physician performs a short exchange (instead of the traditional long-wire exchange, which in biliary procedures, requires the assistant to stand well out of the sterile field in order to assist with the exchange). With certain other devices, the catheter is split or torn away to uncouple it from the wire as the catheter exits the patient. To introduce the device, the coupled portion of the catheter is advanced over the proximal end of the wire guide, while the physician is careful to maintain the wire in position so that its distal end is maintained within the work site and access is not lost. 
     Rapid exchange or short wire techniques have proven particularly desirable in coronary and vascular medicine whereby it is common for a sequence of procedures using multiple catheter-based devices to be performed over a single wire, such as stent placement following angioplasty. Another example of where short wire exchange techniques are often used is in endoscopic procedures performed in the pacreatobiliary system. Typically, an ERCP (endoscopic retrograde cholangiopancreatography) procedure is performed by introducing a catheter device from a duodenoscope through the ampullary orifice (Papilla of Vater) and into the biliary tree, which includes the bile duct, pancreatic duct, and hepatic ducts of the liver. The cannulation device, which typically comprises a sphincterotome/papillotome or ECRP catheter, is introduced into the biliary tree to perform a first operation, which could be diagnostic in nature, such as injecting contrast media, or for therapeutic purposes, such as enlarging the ampullary orifice. When a second medical operation is required, such as to remove a stone, open a stricture, sample tissue, etc., a second or peripheral device, e.g., balloon, basket, snare, biopsy brush, dilator, stent delivery catheter, etc., can be introduced over the original wire guide to perform a secondary therapeutic procedure. 
     While OTW techniques have permitted the exchange of devices, the development of short wire techniques has found acceptance by physicians who prefer to maintain greater control of the wire guide at the scope. Well-known examples of this rapid exchange technology are the devices comprising the MICROVASIVE RX BILIARY SYSTEM™ (Boston Scientific Corporation, Natwick, Mass.) in which the catheter portion of the devices include an internal lumen extending between a distal opening and a proximal side opening spaced 5-30 cm therefrom, depending on the device, thereby requiring an exchange of that length as the device is being removed over the 260 cm JAGWIRE® Guidewire guide developed for that system. An example of a sphincterotome of this system (AUTOTOME™ Cannulating Sphincterotome) is depicted in  FIG. 1 . Extending proximally from the proximal side opening, the lumen forms a ‘C-channel’ (shown in  FIG. 2 ) that holds the wire guide within the catheter as the catheter portion is introduced into the scope, but allows the wire to be laterally pulled out of the channel to gain access of the wire at the biopsy port of the scope as the catheter is being removed from the scope ( FIG. 3 ), so that a second catheter type device (e.g., balloon, basket, stent delivery catheter, etc.) can be subsequently fed over the proximal end of the wire. As the distal portion of the first device is exiting the scope, a short exchange is required (coordinated push-pull movements between the physician and assistant) that is similar in practice to that used in an OTW procedure, until the physician gains control of the wire and the assistant can pull off the first device without risking loss of access. The proximal end of the wire guide is typically secured to the scope during much of the procedure to prevent loss of access, but it must be disengaged from the scope to allow the exchange and removal of the catheter. 
     While the Microvasive system has offered modest time savings, more physician control of the wire, and placed less reliance on the skill of the assistant to help perform the exchange, a short exchange procedure is still required in which care must be taken to prevent loss of wire guide access to the duct, particularly since the wire guide cannot be secured to the scope during removal of the catheter. Because the wire guide resides in the channel of the catheter and the coupled devices are constrained together in the accessory channel, uncoupling must take place as the distal portion of the catheter exits the proximal end of the scope. The process is further slowed by the frictional resistance between the wire and catheter, which remains a problem in subsequent exchanges as devices are fed or removed over the wire residing in the catheter lumen or C-channel. 
     Having a C-channel extending along the catheter can result in certain clinical disadvantages. For example, the split in the catheter provides an entry point for blood and bile, a known source of viruses and bacteria, to enter the catheter lumen and migrate to the proximal end of the device where they typically leak out onto the floor and clothing of those involved in the procedure. The channel also represents a point of potential air leakage, which can compromise the ability to maintain adequate insufflation within the duodenum during the procedure, Another disadvantage of a C-channel is that it degrades the integrity of the catheter, which can be problematic in a cannulating device (such as a deflecting Sphincterotome) when attempting to push through or ‘lift’ the papilla to straighten the entry pathway into the duct, or when pushing through a stricture. 
     The current rapid exchange or short wire system also fails to address some of the shortcomings found in the traditional OTW method. For example, recannulation of the papilla is required when placing multiple plastic drainage stents side by side since the delivery system must be removed to disconnect the wire. Furthermore, existing devices do not offer the ability to place a second wire guide after the first one, such as to place stents in multiple ducts, since the catheter, which could otherwise serve as a conduit, must be removed from the patient and work site before it would have a free lumen for a second wire. Another disadvantage of current systems for exchanging biliary devices is the incompatibility between the two systems. Long wire devices lack the side access port for use with a short exchange wire and the MICROVASIVE RX BILIARY SYSTEM™ devices with C-channels are poorly configured for long wire exchange since once the C-channel has been breached during the first exchange, it is difficult to introduce a long wire through the proximal wire guide access port (which includes the open channel) and keep it from slipping from the channel as it is being introduced. Further, the C-channel is typically not compatible with smaller-diameter wire guides (less than 0.035″) for the same reason. Incompatibility between systems means that physicians cannot take advantage of all of the choices available when selecting the best device and treatment for a particular patient. 
     What is needed is an improved short-wire system and technique for efficiently and reliably exchanging devices within a work site which is compatible with long wire exchange method and which addresses the other deficiencies described above. 
     SUMMARY OF THE INVENTION 
     The foregoing problems are solved and a technical advance is achieved in an illustrative system and method for introducing and exchanging multiple elongate medical devices, e.g., tubular members such as catheters and the like, over an indwelling guiding member, such as a wire guide, within a patient by remotely uncoupling the first device (primary access device) from the guiding member within the work site (defined as a lumen, duct, organ, vessel, other bodily passage or cavity, or the pathway leading thereto in which wire guide/guiding member access is maintained throughout a particular procedure or series of procedures), thereby facilitating the removal of the device and simplifying introduction of a secondary access device over the indwelling wire without an exchange of devices taking place outside of the patient. While the primary focus of this application is the exchange of devices within the pancreatobiliary system or elsewhere in the gastrointestinal tract, the system and method of remote uncoupling of devices within a work site can be adapted for any part of the body to perform any suitable procedure where the exchange of devices takes place over an indwelling guiding member. Examples include, but are not limited to the introduction and placement of balloons, stents, grafts, occluders, filters, distal protection devices, catheters for ablation, phototherapy, brachytherapy etc., prosthetic valves, or other instrumentation or devices into the vascular system, including the coronary arteries, peripheral arterial system (e.g., carotid or renal arteries), or venous system (e.g., the deep veins of the legs). Other exemplary sites include the genito-urinary system (e.g., bladder, ureters, kidneys, fallopian tubes, etc.), and the bronchial system. Additionally, the present system and method can be used for exchanging devices within body cavities, e.g., the peritoneum, pleural space, pseudocysts, or true cystic structures, via percutaneous placement and exchange through a needle, trocar, or sheath. 
     The basic system of devices for remote uncoupling comprises a guiding member, typically a wire guide. It should be understood that hereafter, the term ‘wire guide’ is used in the specification in a generic sense to include any device (e.g., small-diameter catheter, laser fiber, string, plastic beading, stylet, needle etc.) configured to perform the same function, although such a device technically may not be considered a wire guide (or ‘guidewire’) as the term is most commonly used in the medical arts. Remote uncoupling permits a shorter guiding member/wire guide to be used than for other short wire methods (e.g., rapid exchange), and thus hereafter, the methods described in this specification are referred to collectively as the ‘ultra-short wire’ technique, or depending on the work site, ‘intraductal exchange’ (IDE), ‘intravascular exchange’ (IVE), etc. The reason that the wire guide can be of a shorter length than traditional rapid exchange wire guides is that there is no exchange outside the patient. In fact, remote uncoupling allows for the exchange wire guide to be shorter than the devices being introduced since the devices are not removed over the wire. For example, the wire guide of the present inventive system of biliary devices (for use in a 145 cm channel duodenoscope) is typically 185 cm (minimum functional length of about 180 cm), as opposed to the 260 cm wire guide typically used for the Microvasive ‘rapid exchange’ procedures in which a 5 to 30 cm external exchange must be performed each time, depending on the device used. The shorter wire is easier to manipulate by a single operator and helps prevent it from contacting non-sterile surfaces, such as the floor, patient bed, instrument table, imaging unit, etc. The 185 cm length still permits most external changes to be performed, if necessary. To accommodate a longer wire for exchanging a device otherwise not compatible with the system, an optional coupling mechanism on the proximal end of the wire can be included to engage a wire guide extender portion to lengthen the wire (e.g., to 260 or 480 cm) and permit a traditional exchange to take place. 
     Coupled to the guiding member/wire guide is a first elongate medical device (the primary access device), typically a tubular member or catheter device, which includes a coupling region, such as a passageway or lumen, external channel, outer ring, or other interface area, located about the distal portion and which is configured to receive a portion of the wire guide such that both devices can comprise a releasably coupled pair while operating within a work site. The coupling region may be an integral part of the elongate medical device or may located about a separate element disposed therewith (e.g., an elongate engagement member), which for purposes of this application is considered part of the elongate medical device. A separate elongate engagement member can provide a primary or secondary means of releasably securing the wire guide and catheter device until they are to be repositioned or uncoupled. The elongate engagement member, typically but not necessarily disposed within the passageway of the tubular member, can further comprise the coupling region as well. Preferably, the primary access devices used with this system have a closed or self-sealing passageway extending to the proximal (external) portion of the device (instead of an open or split channel) such that the system can be readily converted to introduce a long wire if a long wire-compatible device is selected. Further, the devices of this invention are configured for traditional short wire exchange back over the wire, if so desired, or when remote uncoupling becomes problematic (e.g., due to unexpected anatomical constraints). 
     In a first aspect of the invention, the system further includes an alignment indicator system, such as a system of indicia (e.g., radiopaque markers, external markings, endoscopic markings, etc.) located about the wire guide and/or first elongate medical device that can be utilized by the operator in locating the position of the distal end or distal portion of the wire guide relative to the proximal end of the coupling region, such as at a side access port or aperture (e.g., scive) through which the wire exits. The alignment indication system advantageously allows the physician to control when the two devices are coupled or uncoupled within the work site and helps provide confirmation that uncoupling has occurred. Without the ability to receive such confirmation, it would be extremely difficult for the physician to attempt, with any confidence, the uncoupling of the catheter from the wire guide (e.g., under fluoroscopic guidance) without knowing when uncoupling has occurred or is about to occur. Depending on the location or work site within the body and the device being delivered, an attempt to ‘blindly’ uncouple devices can lead to loss of wire guide access, especially if the device is prematurely withdrawn with the wire guide still engaged. Furthermore, the amount of relative movement between the device and the wire guide required to ensure that uncoupling had occurred would generally be much greater than if indicia were utilized, thus increasing risks such as the wire guide being withdrawn too far and access lost or encountering situations where there is insufficient space within the work site left for uncoupling to take place. Typical rapid exchange devices are not configured with the necessary radiographic or other appropriate indicia since the exchange procedure is intended to take place outside of the patient. The external exchange is a slower process and dictates removal of the first catheter before another catheter or wire guide can be advanced to the work site over an existing device (which always must be a wire guide or guiding device in traditional rapid exchange). 
     A first series of embodiments of the system of indicia includes radiographic or ultrasonically reflective markings located about one or more of the devices which are used by the operator under an appropriate external guidance system (fluoroscopy, MRI, CT scan, x-ray, ultrasound, etc.) to determine the state of alignment and engagement between the primary or secondary access device and guiding device. A first example comprises radiopaque or high-density bands, markings, etc., located on the distal portions of the wire guide and first elongate medical device. In particular, the distal tip of the wire guide includes a radiopaque portion that typically comprises at least the length of the coupling region of the first elongate medical device, which itself includes a radiopaque marker, such as a band comprising iridium, platinum, or other suitable material, located about the proximal end of the coupling region (e.g., at, or just distal to the side access port), thus allowing the operator to know when the distal tip of the wire is nearing or has exited the point of the catheter at which the devices become uncoupled or separate within the work site. Additionally, other radiopaque markers may be present that are generally not used to assist in remote uncoupling, such as at the distal end of the catheter or indicia used for stent or balloon placement. 
     A second series of embodiments of the system indicia comprises directly viewable indicia located about the proximal portions of the wire guide and the tubular member to which it is coupled during the procedure. In one example, the wire guide comprises a visually distinctive alignment point, such as a single mark (e.g., colored band) or a transition point between different colored and/or patterned regions of the wire guide outer coating, which when aligned with a specified first marking on the proximal portion of the elongate medical device, indicates that the distal ends of the wire guide and tubular member are in alignment with respect to one another. The catheter further includes a second mark that represents the disengagement point, that when aligned with the designated alignment marking of the wire guide, is indicative that the two devices are about to or have uncoupled or disengaged with the distal tip of the wire guide having exited the coupling region. Preferably, the first (distal) and second (proximal) markings on the proximal portion of the catheter are located within a region that remains external of the patient or scope during a procedure and are spaced apart by the same distance as the length of the coupling region. For very short coupling regions (e.g., rings), a single mark on the catheter may be preferable to indicate disengagement, if proximal indicia are to be used. 
     A third series of embodiments of the system of indicia include markings that are configured to be viewable by a fiberoptic endoscope or videoendoscope (e.g., duodenoscope, gastroscope, bronchoscope, ureteroscope, etc.). In devices configured for accessing the pancreatobiliary system, the indicia comprise a marking located on both the wire guide and elongate medical device disposed within an intermediate portion of each, which is typically located distal to the viewing lens or video chip of the scope, but proximal to the ampullary orifice during a typical procedure, such that they can be aligned by using the video monitor (or viewing port) to ascertain that uncoupling within the duct has occurred. The device may include other endoscopic indicia useful during the remote uncoupling procedure. For example, a biliary catheter may include a depth marking at a designated distance from the catheter tip (e.g., 10 cm) which when buried within the papilla, indicates that IDE can be performed safely within the duct without risking loss of wire guide access. Furthermore, the distal portion of the wire guide can be distinctive in appearance (e.g., black) as a visual cue to warn the physician if the tip is in danger of pulling completely out of the duct, which would require recannulation of the papilla, The second and third system of indicia do not require external imaging, thus the physician can advantageously limit the time that the patient is exposed to fluoroscopy. For example, fluoroscopy can be used only at selected, critical times during the procedure with at least one of the other types or indicia being used elsewhere for alignment guidance. 
     In addition to the use of visual indicia to confirm whether the wire guide and first elongate medical device (and subsequent devices) are engaged or uncoupled, the present invention includes other types of alignment indication systems, such as a tactile system that includes one or more protuberances and/or indentations along one or more of the devices or the endoscope accessory channel port to allow the physician to ‘feel’ or sense the point where disengagement has occurred or is imminent due to the discrete point(s) of increased resistance between the device as they move relative to one another. Magnets can be a part of a tactile system as well. Other embodiments of the alignment indicator system include sensor-based systems in which a sensor located within the system, such as along the catheter or endoscope channel/port, detects a calibrated location elsewhere in the system (e.g., the wire guide or catheter) and emits or provides a signal or cue (e.g., electrical signal) that is relayed to the operator in the form of an audio or visual alert that warns the operator that the devices have or are about to become uncoupled. The alignment system can comprise a single system or means for alignment, or any combination of visual and non-visual indicators. 
     In a second aspect of the invention, a method is provided for uncoupling the first elongate medical device from the wire guide while both are still dwelling within the work site (i.e., the basic ultra-short wire technique). Both devices are introduced into the work site, using a standard introduction method and introducer member such as an endoscope, introducer sheath, etc., with the wire guide engaged through the coupling region of the medical device being introduced. In one embodiment for use in the pancreatobiliary system, the coupling region comprises a passageway within the distal portion of the catheter, such as the distal 6 cm thereof, with the wire guide exiting at that point through a side access port (e.g., scive) such that the wire guide coextends along the outside of the proximal portion of the catheter as both reside side by side along the introduction pathway, which in the biliary embodiment comprises the channel of the duodenoscope. For example, a wire guide or primary access device, such as a sphincterotome, needle knife, ERCP catheter, etc., may be introduced first to cannulate the duct, with the primary access device being subsequently advanced over the wire to perform a first medical operation that is diagnostic and/or therapeutic in nature, During this time, the wire guide is preferably secured in place by attaching the proximal portion to the endoscope via a locking device, clip, other means located about wire guide entry port (biopsy port), thus fixing its position longitudinally to assist with maintaining access to the work site, Once the first device has performed its intended operation (inject contrast media, ablate the sphincter, etc.), the operator preferably uses the radiographic, endoscopic, and/or proximal system of indica to provide visual guidance during repositioning of the devices to permit disengagement. One technique (referred to herein as ‘device IDE’) includes advancing the primary access device over the stationary wire guide until uncoupling has occurred. A second technique (referred to herein as ‘wire guide IDE’) includes withdrawing the wire guide while maintaining the primary access device in a stationary position until the alignment indicia indicates that uncoupling has occurred. A third technique would involve a combination of the device and wire guide IDE. Also, there typically is a characteristic ‘whipping’ action of the radiopaque wire guide tip portion upon exit from the passageway that is viewable under fluoroscopy which also provides a visually distinctive indicator of uncoupling. 
     When the physician, using at least one component of the alignment indicator system, has determined that the tip of the wire guide has disengaged from the coupling region of the primary access device, the first device can be easily removed by merely pulling it back out of the endoscope accessory channel (or introducer sheath in the case of vascular or certain other non-endoscopic applications). Removal is greatly facilitated by the elimination of friction which would have otherwise existed between the wire guide and catheter if the wire resided within the channel or lumen. Although some of the aforementioned MICROVASIVE RX™ biliary devices (e.g., the AUTOTOME™ sphincterotome) include a side port within the distal portion, all of the devices lack the combination of indicia that make a remote or intraductal exchange clinically practical or even possible. Furthermore, those devices that include an open channel extending proximally of the side access port cannot be uncoupled within the duct or work site regardless of the lack of indicia since the proximal portion of the wire guide tends to ‘seek’ and reenter the channel when both devices are residing within the accessory channel of the scope. Thus, remote disconnection is rendered impossible without some means to releasably disengage the wire from the channel. 
     After the catheter and wire guide are uncoupled, the proximal end of the wire is available for a third elongate medical device (e.g., a secondary access device or a second device that is the same as the first) to be advanced thereover to the work site. In one example of the method, the proximal end of the indwelling wire is fed through the distal opening and out of the side access port of the secondary device, which is then advanced to the work site. If after the second medical operation using the secondary device, another secondary device is required for another operation, the first secondary device (third medical device) is removed from the wire guide and the patient, and the wire guide is available to provide access for a fourth device in the same manner as the first two. 
     In a variation of the present method, the primary access device may be left in place at the work site after disengagement with the wire guide to serve as an introduction pathway or conduit for a second wire guide, such as for a procedure where two branches of a duct or vessel are to be cannulated. An example of such a procedure is when a stent must be placed in two different ducts draining separate lobes of the liver. The second wire guide is typically introduced through a proximal wire guide port or hub of the first device, typically disposed about the handle portion, the port communicating with the passageway. This technique typically requires a long-wire exchange of the catheter. A second option is to introduce the wire through a proximal side access port (e.g., a scive) formed through the wall of the tubular member so that full control of the wire is maintained. In this embodiment, the catheter walls are configured to be splittable between the proximal and side access ports, or include an open or self-sealing channel through which the wire guide can be stripped out toward the distal portion of the device such that a long exchange is not required. Removing or stripping the wire guide laterally from the passageway can be done by any well-known means, such as scoring or structurally weakening a wall of the catheter, using a splittable, anisotropically oriented catheter wall material (e.g., PTFE), incorporating a sealable or locking seam therealong, or by thinning the wall and/or using a material that allows the wire guide to split the wall and form its own exit pathway when sufficient force is supplied. Alternatively, a wire guide that includes a coupling region, such as an attached sleeve, can be used to couple to a standard wire guide that is already indwelling, or both wires can be coupled together and advanced through the passageway of the elongate tubular member. 
     After gaining access to the passageway by one of the aforementioned routes, the wire guide is guided under external imaging, such as fluoroscopy, into the desired location. Optionally, if the first device is a sphincterotome or other type of deflectable catheter, the operator can manipulate the shape and orientation of the catheter tip portion to help guide the tip of the second wire guide into the opposite (or side) branch of the duct or vessel. Orientation within the work site can be facilitated with a rotatable handle to direct the tip. Furthermore, it has been demonstrated that certain shorter wire guides, such as the illustrative 185 cm biliary wire guide of the present invention, are sufficiently torqueable such that an operator can simply rotate the wire with his or her fingers to achieve similar results in most instances. 
     In another aspect of the invention, primary access devices further include an elongate engagement member configured to releasably engage with the wire guide within or about the coupling region (e.g., the distal passageway of the tubular member). Embodiments include using a flexible wire stop (e.g., a nylon stylet) configured to wedge the wire guide within the passageway when in the fully advanced position, and a thread-like member (e.g., suture) that ensnares the wire guide and provides tension to maintain it in a longitudinally secure position relative to the tubular member. When an elongate engagement member is not used during introduction, such as when secondary access devices are being introduced over the already indwelling wire guide, a stiffening stylet may be optionally maintained in the passageway of the tubular member to add rigidity to the device during introduction and/or for advantageously traversing scives in the tubular member, such as the side access port, to prevent kinking thereabout. 
     In still another aspect of the invention, the system of devices adapted for remote uncoupling or ultra-short wire techniques includes a delivery catheter for plastic tubular drainage stents and a technique for deployment that allows for placing multiple stents side by side within the bile duct using a single cannulation procedure. By placing the side access port on the inner carrying member (over which the stent is mounted) at a point distal to the stent, the wire guide can be uncoupled within the duct and the stent deployed without having to withdraw the entire system, including the wire, in the process. The junction between the inner carrying member and wire guide can be advantageously used to ‘catch’ the stent when the inner member is pulled back, thus allowing the entire delivery system, including the stent, to be pulled back within the duct. This feature, which is not present in other stent delivery systems, is especially important to address situations when the stent is advanced too far into the duct and needs to be repositioned. After the stent is in the correct position for deployment, the inner carrying member is advanced and/or the wire guide withdrawn to uncouple the two, allowing the inner carrying member to be withdrawn through the stent and from the duct while the wire guide remains behind for a second stent delivery catheter (and additional stents) to be advanced into the duct and placed along side the first stent. Pigtail stents and others that include shaped distal portions for anchoring can be temporarily straightened during delivery by the wire guide which traverses the coupling region. 
     In still another aspect of the invention, the wire guide can be placed through the mouth by dragging or carrying the wire down using a endoscope and guide wire carrying mechanism that either resides in the channel of the scope and engages the wire guide about the scope tip, or attaches to (or co-extends with) the scope and engages the wire guide alongside. The treatment site, such as the gastroesophageal (GE) junction, is visualized and the distance to the mouth is measured using scale indicia located on the proximal portion of the scope. The wire guide, still coupled to the wire guide carrying mechanism, is then advanced a known distance (e.g., 10 cm) past the treatment site and into the stomach where uncoupling takes place following treatment. The wire guide includes a reference marking (e.g., at 10 cm) which lies at a known reference point relevant to treatment, such as the GE junction. The proximal portion of the wire guide preferably includes scale indicia, such as different colored bands or intervals (e.g., 5 cm) having different numbers or types of markings that reference a particular distance (typically using non-numerical indicia) to the reference mark at the GE junction. With the wire guide in position, the operator advances a primary access device, such as a dilator, PDT balloon, achalasia balloon etc., using corresponding indicia on the proximal portion thereof that align with that of the wire guide to guide placement of the device to the desired treatment site, such as the GE junction. If a secondary access device is required, such as a larger dilator, the first device is advanced into the stomach over the wire and uncoupled so that the wire becomes available for the next device to be fed thereover. Carrying the wire outside of the scope to a treatment site, which may also include the jejunum or other portions of the gastrointestinal tract, advantageously provides a means for placing devices larger than scope accessory channel, while still retaining the benefit of endoscopic navigation within the patient. 
     In still another aspect of the invention, a method and apparatus for uncoupling a wire guide from and elongate medical device is provided and comprises a catheter shaft having a wire guide lumen extending there through, wherein the material surrounding the wire guide lumen is selected or adapted to facilitate splittability for removal of the wire guide. The catheter shaft includes a wire guide port having a stress riser along a portion thereof. The stress riser is configured to reduce the force necessary to rupture or split the portion of the shaft wall adjacent to the wire guide port. In a preferred aspect of the invention, the catheter shaft is coextruded and comprises a plurality of materials. The portion of the shaft adjacent the wire guide lumen is formed from a first material and the balance of the shaft is formed from a second material. The first material is selected or adapted to facilitate splittability as compared to the second material. The first material may have a lower durometer than the second material. In still another aspect of the invention, a peel tool is provided for use in separating the wire guide from the catheter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  depicts a perspective view of a prior art sphincterotome adapted for short-wire exchange; 
         FIG. 2  depicts a cross-sectional view taken along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  depicts the device of  FIG. 1  being used with an endoscope; 
         FIG. 4  depicts a side view of an illustrative catheter configured for use in the illustrative system and method; 
         FIG. 5  depicts a cross-sectional view of the distal portion of the embodiment of  FIG. 4  and illustrative wire guide coupled thereto; 
         FIG. 6  depicts a side view of an embodiment of the present invention wherein the coupling region comprises an external channel; 
         FIG. 7  depicts a side view of a wire guide in which the proximal portion is oriented at an angle relative to the distal and intermediate portions; 
         FIG. 8  depicts a side view of an embodiment of proximal system of indicia located on the first elongate medical device and wire guide; 
         FIGS. 9   a - f  depict the steps of an example of the present method in which multiple catheter devices are exchanged over a guide wire within the common bile duct; 
         FIG. 10  depicts a side view of an embodiment of the present invention wherein the first elongate medical device comprises a sphincterotome; 
         FIG. 11  depicts a view in situ of a sphincterotome of the present invention being used to introduce a second wire guide into a branch of a passageway; 
         FIG. 12  depicts a perspective view of an illustrative wire guide holding device of the present system and method; 
         FIG. 13  depicts a side view of a wire guide having a coupling mechanism for attaching a second wire guide to the proximal end thereof; 
         FIG. 14  depicts a side view of a retrieval basket of the present invention that includes a coupling ring to engage the wire guide; 
         FIGS. 15-16  depict cross-sectional views of sphincterotome catheters comprising a splittable wire guide passageway; 
         FIG. 17  depicts a side view of a biliary stent and delivery catheter of the present invention; 
         FIG. 18  depicts a side view of an embodiment of the present invention comprising a splittable region in the tubular member; 
         FIG. 19  depicts a side view of a dilation balloon of the present invention; 
         FIG. 20  depicts a side view of an extraction balloon of the present invention; 
         FIG. 21  depicts a side view of a biopsy device of the present invention; 
         FIG. 22  depicts a side view of a self-expanding prosthesis delivery apparatus of the present invention; 
         FIG. 23  depicts a partially sectioned side view of a first embodiment of an elongate engagement member (distal portion) comprising a wire stop member; 
         FIG. 24  depicts a side view of the proximal portion of the embodiment of  FIG. 23 ; 
         FIG. 25  depicts a partially sectioned side view of a second embodiment of the elongate engagement member comprising a thread-like member; 
         FIGS. 26   a - b  depict a third system of indicia located on the intermediate, viewable portion of the coupled devices of the present invention; 
         FIG. 27  depicts a cross-sectional view of a stent and pusher apparatus of the present invention; 
         FIG. 28  depicts a cross-sectional view of radioactive seed delivery apparatus of the present invention; 
         FIGS. 29   a - e  depict a method of delivering multiple stents within the common bile duct using the system embodied in  FIG. 17 . 
         FIG. 30  depicts a partially sectioned view of a wire-guided wire of the present invention; 
         FIGS. 31-32  depict partially sectioned views of embodiments of the present invention in which the coupling region is located on a separate member; 
         FIG. 33  depicts a side view of an embodiment of the present invention have two distal side access ports; 
         FIG. 34  depicts perspective view of an embodiment of the present invention in which the wire guide hooks into the side access port; 
         FIGS. 35   a - b  depicts side views of a hooked wire guide before and after uncoupling; 
         FIG. 36  depicts a side view of an embodiment of the present invention comprising a pair of slotted coaxial members. 
         FIG. 37  depicts a cross-sectional view of the embodiment of  FIG. 36  taken along line  37 - 37 ; 
         FIG. 38  depicts a partially sectioned view of an introducer member of the present invention; 
         FIG. 39  depicts a partially sectioned view of a delivery catheter of the present invention; 
         FIG. 40  depicts a side view of and embodiment of the present invention comprising a tactile alignment indication system; 
         FIG. 41  depicts a side view of a pigtail drainage catheter of the present invention in its deployed configuration; 
         FIG. 42  depicts a partially sectioned view of the embodiment of  FIG. 41  coupled to a wire guide; 
         FIG. 43  depicts a side view of an alternate embodiment of a drainage catheter having anchoring flaps; 
         FIG. 44  depicts a side view of a dilator catheter of the present invention; 
         FIGS. 45   a - b  depict a side view of a wire guide of the present invention adapted for being carried by an endoscope to a work site; 
         FIG. 46  depicts a side view of device attached to an endoscope which is configured for carrying the wire guide of  FIGS. 45   a - b;    
         FIG. 47  depicts an end view of the embodiment of  FIG. 46 ; 
         FIG. 48  depicts a side view of a wire guide carrying mechanism of the present invention; 
         FIG. 49  depicts a cross-sectional view of the distal portion of embodiment of  FIG. 48  engaging a loop tip wire guide; 
         FIG. 50  depicts a side view of the loop tip wire guide of  FIG. 49 ; 
         FIG. 51  depicts a side view of a photodynamic therapy balloon of the present invention; 
         FIG. 52  depicts a plan view of a the devices of  FIGS. 50 and 51  being introduced through a bite block/wire guide holder of the present invention; 
         FIG. 53  depicts a side view of an achalasia balloon of the present balloon; 
         FIG. 54  depicts a partially sectioned view of a naso-enteric tube of the present invention including a stiffening stylet; 
         FIGS. 55   a - f  depicts steps of esophageal dilation using the present method; 
         FIG. 56  depicts a side view of an dilator having a reduced diameter portion proximal to the side access port; 
         FIG. 57  depicts a wire guide of the present invention that includes a lubricious intermediate portion; 
         FIG. 58  depicts a portion of a catheter device having a splittable wire guide passageway comprising a thin catheter shaft wall; 
         FIG. 59  is a graphical representation of the rupture force for different catheter shaft materials; 
         FIG. 60  depicts a cross-sectional view of a catheter device comprising a coextruded shaft material; 
         FIG. 61  depicts a portion of a catheter device comprising a coextruded shaft material; 
         FIGS. 62-65  depict cross-sectional views of alternative embodiments of a catheter device comprising a coextruded material; 
         FIG. 66  depicts a sphincterotome comprising a coextruded catheter shaft; 
         FIGS. 66   a - c  depict an enlarged view of the intermediate wire guide port of the sphincterotome illustrated in  FIG. 66 , wherein the wire guide port includes a stress riser; 
         FIGS. 67-77  depict embodiments of a peel tool for use in separating a wire guide from a catheter; and 
         FIGS. 78-83  depict various embodiments of a wire guide port having a stress riser disposed along a portion thereof. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative system and method for introducing a series of medical devices over a wire guide into a patient by remotely uncoupling the first device from the wire guide inside of the patient without utilizing a long wire or standard short wire exchange procedure is embodied in  FIGS. 4-57 . A first exemplary embodiment of the system is depicted in  FIGS. 4-5 , which comprises a first elongate medical device  10 , such as the illustrative tubular member  77  or catheter that includes features similar to the GLO-TIP II® E.R.C.P. Catheter (Wilson-Cook Medical, Inc.), the catheter further including a coupling region  14  having a first, distal end  75  (oriented toward the distal end of the device), a second, proximal end  76 , and an interconnecting passageway  31  sized and configured to receive a standard-diameter exchange wire guide  11  (e.g., METRO® Wire Guide; Wilson-Cook Medical, Inc.) or other guiding device suitable for coupling to the first elongate medical device  10 . The coupling region  14 , generally located about the distal portion  13  of the tubular member  77  (first elongate medical device  10 ), may be coincident with the distal portion of the main passageway  27  (as depicted) or separate therefrom. The distal portions  13 , 60  of the fist elongate medical device  10  and the wire guide  11 , to which the former is coupled via the coupling region  14 , are generally defined as the portion of each that are disposed within the work site during the medical operation and the subsequent uncoupling of the two devices. For purposes of this disclosure, the work site is defined as the lumen, duct, organ, vessel, other bodily passage/cavity, or the pathway leading thereto, in which wire guide access is maintained to perform a particular medical procedure/operation or series of procedures. For example, in a procedure involving the biliary system, the work site is considered the common bile duct, including the pancreatic duct and the ducts extending into the lobes of the liver. 
     The coupling region is configured to permit the first elongate medical device  10  to be co-introduced over the wire guide (either sequentially or together) into the work site in a coupled state (e.g., with the wire guide  11  traversing the passageway  27  of the first device  10 ) such that the proximal portion  59  of the wire guide exits the passageway and is external to the tubular member  77  as the wire guide  11  and tubular member exit the patient or scope. Like traditional forms of short wire or rapid exchange, this gives the physician more control over the wire at that point. In the illustrative coupling region  14  of  FIGS. 4-5 , the first end  75  thereof comprises a distal opening  19  in the tubular member  77 , and the second end  76  comprises a side access port  15  or scive traversing the side wall of the tubular member  77  and located approximately 6 cm from the distal end  12  of the tubular member. The illustrative coupling region  14  is located within the distal portion  13  of the first elongate medical device  10  with the coupling region passageway  31  comprising the distal portion of the main wire guide passageway  27 . The range of lengths of the coupling region  14  or the distance of the side access port  15  (or second end  76 ) from the distal end  12  of the elongate member  10  can vary according to the device and application as long as the disconnect point is sufficiently close to the distal end of the device to allow for remote uncoupling within the work site. It has been determined that 6 cm is an advantageous coupling region length for many biliary devices of the present invention in that it provides a sufficient length to prevent accidental uncoupling, while still allowing for the anatomical constraints of the duct such that, in most instances, there remains sufficient room for the relative movement required for uncoupling. 
     For biliary applications, the length of coupling region could range from less than 1 cm (e.g., a ring) to at least 15 cm. A more preferred range for most devices would be approximately 3-10 cm with the most preferred range being approximately 5-7 cm. For devices intended for the pancreatic duct, the ideal distance of the side access port  15  to the distal end  12  would be 2-5 cm, given the shorter available distance in which to work. In devices intended for use in body cavities where space is even tighter, the side access port  15  may need to be placed closely adjacent to or at the tip  12  of the device in order for an exchange to be successfully accomplished. On the other hand, procedures in which loss of wire guide access in not particularly of concern, such as in certain vascular procedures and when working in long passageways, such as in the intestinal tract, there may be more options as to where the side access port  15  and coupling region  14  can be located. 
     The illustrative side access port  15  comprises a semicircular opening (in a cross-sectional view or ovoid shape from a top view) that typically comprises approximately ¼ to ⅓ of the width of the catheter; however, any opening size or shape that permits passage of the wire guide therethrough is possible. It may be advantageous to reinforce the side access port  15  area with one or more wires, sheaths, bands, braiding, or other means which traverse, are bonded to, embedded within, or otherwise reinforce the tubular member at least within the area about the wire guide exit port (side access port) to prevent kinking at that location. The wire guide  11  extends proximally from the distal opening  19  of the first device  10  and exits the passageway  31  and coupling region  14  proximally through the side access port  15 , thereby giving the physician access to the proximal end of the wire such that it can be manipulated and locked or otherwise secured during the procedure, if so desired. As noted above, a relatively short distance of the coupling region  14  advantageously allows the coupled devices to be moved relative to each another by a sufficient distance to disengage or uncouple one from the other by advancing the catheter  10  toward the distal tip  25  of the stationary wire guide  11 , withdrawing the wire guide until it pulls through the catheter and exits the side access port  15 /coupling region  14 , or a combination of forward catheter movement and wire guide withdrawal, all preferably in such a manner that the wire guide still remains within the work site (e.g., the duct) to facilitate access by subsequent devices over the indwelling wire. 
     Insomuch that no external exchange is required with the present invention, it is only necessary to size the length of the wire guide  11  to account for the furthest point the distal portion  60  is to be advanced into the work site (e.g., for uncoupling to take place), the intermediate portion  97  extending from work site, to the outside of the patient or scope, and the proximal portion  59  ( FIG. 7 ) extending therefrom for a length sufficient to be manipulated by the operator, such as to lock the wire guide in place. In the illustrative biliary embodiment, the wire guide  11  is 185 cm in length so as to provide a minimal, but adequate extension of the wire from the scope accessory channel; however, other procedures might necessitate a shorter or longer length. Although the length of the wire guide  11  need only be of sufficient length to manipulate or lock or secure in place, if necessary, the proximal portion  59  preferably should be sized to accommodate a traditional short wire exchange procedure, using the appropriately configured devices, if one is required (such as when remote uncoupling may not be possible or desirable for some reason). The wire guide  11  is preferably sized to slidably and releasably reside within the coupling region with minimal friction, although a mechanism is contemplated as part of the present invention in which the catheter (or coextending ancillary device) releasably engages and locks with the wire at a particular point therealong. The coupling region  14  of  FIG. 5  comprises the distal portion of the passageway  27  (passageway  31 ), with the proximal portion  28  of the passageway providing a continuation of the lumen that extends proximally from the point of the side access port  15 . Alternatively, the proximal passageway  28  can be at least partially blocked or restricted (with a moveable flap or a permanent obstruction, such a plastic or metal insert) just proximal to the side access port  15  to serve as a guide or ramp that helps the wire guide being loaded from the distal opening  19  to be able to more readily exit through the side access port, rather than continuing on into the proximal passageway. The blocking means (not shown) may also advantageously restrict fluid or other materials from passing through the passageway retrograde direction. In a related embodiment, the wire guide passageway  27  extends proximally only to the side access port  15 , terminating at that point. 
     While the illustrative coupling region  14  of  FIGS. 4-5  represent a preferred embodiment for applications in which having the wire guide  11  extending from the distal opening  19  of the tubular member  77  is particularly advantageous, such as for primary access devices used to cannulate a tight stricture, such as the ampullary orifice, it should be noted that any structural adaptation that allows for temporary coupling of the wire guide to a device being introduced therewith or thereover can comprise an embodiment of the coupling region  14  for purposes of remote uncoupling. For example,  FIG. 6  depicts a alternative embodiment of the present invention in which the coupling region  14  comprises an external coupling element or channel  30 , rather than a portion of the tubular member passageway  27 . The illustrative external channel  30 , which includes a passageway  31  extending therethrough, can either be integrally formed with the catheter body, or can be bonded or otherwise attached to the outside thereof. Additionally, the external channel  30  can comprise a short piece of sheath encircling the tubular member  77 , a plastic or metal ring, or any structure that can form a passageway  31  capable of forming a coupling region  14  with the wire guide. 
       FIG. 30  depicts an embodiment of an external channel  30  for a device not having an internal passageway. The elongate medical device  10  comprises a wire-guided wire  111  in which the coupling region  14  comprises a outer channel  30  comprising a outer sleeve  112  of shrink wrap material bonded to the wire  111  and a inner sleeve  113  of a radiopaque material bonded to the first sleeve  112  as indicator  17 , 18  of the first and second ends  75 , 76  of the coupling region  14 . Either a standard wire guide (such as a 0.021″ METRO™ wire guide) is fed through the coupling region and the two wires are advanced through an already indwelling tubular member to the work site, or the wire-guide wire  111  is fed over the proximal end of an indwelling standard wire guide (which could also be coupled to a tubular member) and advanced to the work site, where it is uncoupled therein. 
       FIG. 14  depicts another alternative embodiment in which the coupling region  14  comprises a coupling ring  63 , which in the illustrative embodiment is attached to the distal tip  74  of a retrieval apparatus  64 , such as the illustrative wire retrieval basket  64  for capturing biliary stones (a modification of the WEB™ Extraction Basket, Wilson-Cook Medical, Inc.). The illustrative ring  63  is advantageously made to pivot so that it can better accommodate the wire guide  11  which passes therethrough to engage with the first device  10 . Coupling rings  63 , while not providing as secure of an engagement of the internal passageway, represents an option for certain types of devices lacking a suitable passageway within the shaft portion of the elongate medical device  10  (made of coiled wire in this particular embodiment). The ring  63  requires the least amount of relative movement between devices for uncoupling, which can be advantageous in short work sites or when faced with other anatomical constraints. 
       FIGS. 31-36  depict a series of alternative coupling region  14  embodiments.  FIG. 31  depicts a tubular member  77  in which the coupling region  14  is located on a separate element, which in the illustrative embodiment, comprises an elongate engagement member  89  comprising a shaft portion  164  slidably disposed in a second passageway  115  and extends from the distal end  12  of the tubular member  77  and engages the wire guide  11  via a cannula portion  115  that includes first and second openings  75 , 76  through which the wire guide  11  is fed. By locating the elongate engagement member  89  within a second passageway  115 , the first passageway  27  remains available for infusing materials or passing a second wire guide therethrough. The embodiment of  FIG. 32  also includes a separate elongate engagement member  89  in a second passageway  115  with the elongate engagement member  89  further comprising the coupling region  14 . In this illustrative embodiment, the elongate engagement member  89  extends from the side access port  15  and includes a distal ring or loop  45  which ensnares the wire guide and couples the devices together. Optionally, the loop  45  can be made collapsible to pull through the passageway  115  after uncoupling. 
       FIG. 33  depicts a tubular member in which the first end  75  of the coupling region  14  terminates proximal to the distal end  12  of the member, and the second end  76  comprises a side access port  15  located about the distal portion  13  of the tubular member. The wire guide  11  is fed into the coupling region  14  such that the distal end  25  of wire guide  11  is directed at an angle from the tip  12  as it exits the most distal side access port (first end  75 ). This configuration allows the physician to be able to rotate the tubular member  77  to advantageously direct the tip  25  of the wire guide  11  in an intended direction, such as into a particular branch  48 , 49  of a bifurcated duct or vessel. The distal end  12  of the tubular member  77  can be closed, or it could include an opening about the tip that could represent a second, alternative first end  75  of the coupling region so that if preferred, the wire guide  11  can also be coupled in the manner similar to  FIG. 5 . 
       FIGS. 34-35   b  depict embodiments of the present invention in which the wire guide  11  is adapted to hook into the coupling region  14  in a coupled configuration. In the embodiment of  FIG. 34 , the wire guide  11  includes a hooked distal portion  116 , such as the illustrative ‘shepherd&#39;s crook’ in which the distal end  25  and adjacent distal portion  60  engage the coupling region  14  of the tubular member  77  via the side access port  15 , residing within the passageway  27  by an amount sufficient to accomplish a secure engagement. Preferably, the wire guide  11  is sized such that there is a adequate frictional engagement with the passageway  27  in which it resides to help prevent accidental dislodgement. In a related embodiment shown in  FIGS. 35   a - b , the distal hook portion  116  of the wire guide  11  is configured to be inserted into the distal opening  19  of the tubular member  77 , which includes a radiopaque marker band  17  closely proximate thereto. The illustrative distal hook portion  116  comprises nitinol or another superelastic material which allows it to be heat set in a helical configuration  117  that once disengaged from the passageway  31  of the coupling region  14 , the hook  116  assumes its predetermined shape and wraps back over itself to create a closed loop end  118 . This configuration better permits a second device to be fed back over the wire guide  11  without the hooked portion  116  interfering with its passage thereover. Optionally, the tubular member  77  can include an open longitudinal channel or recess extending proximally from the side access port  15  or distal opening  19  in which the coupled wire guide  11  can at least partially reside while the devices are being advanced together into the work site. 
     Another embodiment of a method of coupling a tubular member  77  to a wire guide  11  is shown in  FIGS. 36-37  in which the tubular member comprises a pair of coaxial members  100 ,  119  that each include a slotted opening or channel  120 , 121  extending the length of the coupling region  14  (distal end  12  to side access port  15 ) such that when aligned with one another, the wire guide  11  can laterally disengage from the open passageway  31 , which is otherwise enclosed by one of the inner  119  and outer  100  sheath members when they are not aligned. Preferably, the proximal portions of the inner and outer members  100 , 119  (not shown) include proximal makings or structure that allows the physician to determine when rotational alignment has occurred for uncoupling. Alternatively, the slots  120 , 121  can include radiopaque stripes extending therealong that when superimposed on one another or are otherwise aligned in some manner, indicate radiographically that alignment has occurred such the wire guide can disengage from the passageway  31 . 
     The above coupling region  14  embodiments are merely exemplary of the many options from which a skilled person might select to couple a catheter and wire guide together for introducing them to a work site, the choice being influenced by the nature of the procedure and the devices being used. Other selected examples include, but are not limited to releasable or breakable sutures or wires extending along or through the catheter to capture the wire, compatible, engageable surface structure or elements located on both devices, temporary or dissolvable bonds or adhesives, magnets, or other means of temporarily coupling two medical devices. 
     Preferably, devices configured for remote uncoupling include an alignment indicator system that allows the clinician to determine the current state of alignment or engagement between a given device and the wire guide or guiding member to which it is temporarily coupled for a particular procedure. In procedures that utilize fluoroscopic guidance of devices within the work site, strategically located radiopaque indicia conveniently provide a means for determining relative alignment and confirmation that uncoupling has occurred. The invention does not require that a particular imagable maker be of a particular type. For example, ultrasonically reflective markers can be used in place of radiopaque bands or other markers. Further, the number and arrangement of the markers is not critical. The alignment indicator system of the present invention may comprise any suitable system in which the first elongate device  10  and wire guide  11  include a predetermined or precalibrated method or means of providing guidance to the physician via external imaging, direct observation (external or endoscopic), tactile sensation, or monitoring of an audible or visual alarm sensor (e.g., activating an indicator light located about the proximal end of the apparatus) to indicate that uncoupling of the two device has occurred within the work site. 
     Referring now to  FIGS. 4 and 5 , the procedure for uncoupling the first device  10  and wire guide  11  within the work site is greatly facilitated by the addition of a first system of indicia  16  located about the distal portions  13 , 60  of the first device  10  and the wire guide  11 , respectively, that comprise a series of radiopaque markers which provide visual guidance under fluoroscopic imaging to the physician or operator as to when the first device is coupled with the wire guide and when the wire guide has passed through and out of the coupling region  14 . Since relatively few exchange procedures can be performed under direct visual observation, the distal indicia  16  typically include a series of externally imagable bands, marking, or other indicia comprising a radiopaque (high density) material, such as, iridium, platinum, tungsten, gold, barium, tantalum, etc. The indicia are overlaid upon, bonded to, or incorporated into the device at the desired locations, typically a location useful for relative alignment with other radiopaque indicia or structure. The illustrative first (or distal) system of indicia  16  comprises a series of radiopaque markings on both the first elongate medical device  10  (tubular member  77 ) and the wire guide  11 , including an optional distal imagable marking  17  located about the distal end  12  of the tubular member (or first end  75  of the coupling region), a proximal imagable marking  18  located proximate and distal to the side access port  15 , and a distal imagable portion  26  or marker located about the distal end  25  or distal portion  60  of the wire guide  11 . The illustrative distal marking  17  of  FIG. 4  comprises radiopaque ink having sufficient radiopacity to contrast with the catheter shaft, which in the illustrative embodiment, is also made radiopaque by the addition of barium sulfate or other suitable material into the base polymer. The proximal imagable marking  18  comprises an iridium or platinum band that is glued or otherwise affixed to the catheter surface closely adjacent the distal end of the scive comprising the side access port  15 . This band comprises sufficient radiopacity such that it contrasts well with the tubular member to which it is attached, which also may include radiopaque material or pigment, In  FIG. 5 , the distal radiopaque marker  17  of the tubular member  77  comprises a band similar to band  18  at the proximal end  76  of the coupling region (side access port  15 ). The illustrative distal radiopaque wire guide portion  26  ( FIG. 5 ) comprises a coilspring comprising platinum, or another radiopaque material such as tungsten or gold. Use of radiopaque filler material or ink is also contemplated as a means for creating a radiopaque wire guide tip portion  26 . Placement of a radiopaque marker  18  about the second end  76  of the coupling region  14  advantageously provides a target point at which the physician knows if the radiopaque tip  26  of the wire guide has passed proximal thereto and disengagement has occurred. Although in the illustrative embodiments, the marker  18  is typically located proximal and closely adjacent to the side access port, it may also be placed in any suitable position that is useful for alignment with the wire guide, such as proximal of the port or in alignment therewith, such as depicted in  FIG. 6 . Alternatively, the marker  18  can comprise a radiopaque stripe or sleeve that extends the length of the coupling region, rather than being limited to the area adjacent the side access port. One such example is depicted in  FIG. 31  in which the illustrative metal coupling cannula  114  comprises a highly radiopaque material such as platinum or iridium. In the embodiments of  FIGS. 14 and 32 , the coupling region  14  comprises a coupling ring  63  which preferably includes enhanced radiopacity to assist the physician in determining when the radiopaque distal portion  26  of the wire guide has passed through and disengaged from the ring. 
     A second system or type of indicia  21  is depicted in  FIGS. 4 and 8 , and is located on a proximal portion  36  of the first device  10 /tubular member  77  that is external to the patient when the distal portion  13  of the device is residing within the work site. During normal operation, the proximal indicia  21  are directly visible by the clinician during the procedure as a primary or secondary means of determining alignment. In the biliary embodiment of  FIG. 8 , the proximal indicia  21  comprise indicia  35  located about the tubular member  77  and include a series of printed bands that are preferably of a color or pattern contrasting with that of the tubular member  77 , and which extend from 160 cm (the first or distal end  62 ) to the 166 cm mark (second or proximal end  61 ), as measured from the distal tip of the catheter. The first end  62  (160 cm) represents the point at which alignment with a corresponding proximal alignment mark  37  located on the wire guide, comprises the point of alignment  81  which indicates that uncoupling is imminent with further relative repositioning between the two devices  10 , 11 . Repositioning the proximal alignment mark  37  of the wire guide toward the second end mark  61  results in the two devices reaching the point of detachment  82  at which uncoupling takes place, the colored bands serving as warning that the uncoupling is imminent with further repositioning. In the embodiment of  FIG. 4 , the proximal indicia  21  comprise a continuous band of contrasting coloration extending from 160 to 166 cm. As noted, the location of the proximal indicia is not particularly critical, but it is preferably configured such that it remains visible to the operator during a typical procedure. The band  35  can include a gradation of colors, (e.g., yellow to orange to red) to indicate the relative proximity to the point of detachment  82 . In the illustrative embodiment, the 166 cm mark at the proximal end of the indicia band  35  lies proximate the distal end of an optional proximal side access port  20 , which comprises an entry point for a second wire guide into the passageway  27 , the technique therefor being discussed below. For non-biliary applications, such as for vascular, pulmonary, or urological procedures, etc., any proximal indicia  21  most likely would be located at a different lengths from the distal tip of the catheter, one appropriately correlated with the distance required to access the work site. The length of the first device indicia  35  (6 cm) preferably corresponds with the length of the coupling region  14  (shown in  FIG. 5 ). 
     As noted above, the 160-166 cm area of indicia  35  of the proximal indica system  21  advantageously provides a location on the tubular member  77  that will most always be external to the patient and endoscope accessory channel such that it can be viewed by the clinician during the procedure. In the illustrative embodiment, the second alignment point  37  of the wire guide is indicated by a color change between the distal portion  60 , which includes helical striping characteristic of the METRO® Wire Guide (Wilson-Cook Medical, Inc.), and the proximal portion  59 , which comprises solid coloration, such as a section of shrink wrap or coating of a different color and/or pattern that visually contrasts with the distal portion  60  and/or intermediate portion  97  such that the distal 160 cm of the illustrative wire guide are distinct from and different in appearance from the proximal 25 cm. Alternatively, a contrasting color or ink or suitable material can be applied to the outer surface of the wire guide  11 , or a single band can be affixed about the junction  37  between the distal  60  and proximal  59  portions at an appropriate location to establish the point of detachment  82  which occurs by alignment with point  61  of the first device  10 . The second alignment point  37  is located on the wire guide  11  such that when it is aligned with the distal end  62  of the proximal indicia  21 , the distal end  25  of the wire guide is aligned with the distal end  12  of the first device  10 /tubular member  77 . Alternatively, the wire guide could include a single, narrow marking at the second alignment point  37 , or multiple markings, e.g., corresponding to both the proximal and distal ends  61 , 62  of the proximal indicia  21 . The proximal indicia  21  of the wire guide  11  and catheter  10  comprise any suitable means of providing a visual indicator, such as shrink wrap, ink, bands, surface etching or other treatment, etc. 
     A third type of alignment  83  is depicted in  FIGS. 26   a  and  26   b  in which the first and second endoscopic alignment indicators  84 , 85  are located about the intermediate portions of the first elongate medical device  10  (or second catheter, etc.) and wire guide  11 , respectively, in a location such that when the distal portions thereof are advanced within the work site  41 , the first and second indicators  84 , 85  are typically disposed within the viewable area  86  between the Papilla of Vater  40  and the distal end  87  of the accessory channel. This allows the operator to monitor the relative alignment of both to determine when uncoupling has occurred within the duct  41  (biliary system). In the illustrative example, the distal ends of the wire guide and first catheter member (not shown) have both traversed the Papilla of Vater  40 , and entered the bile duct  41 . An optional marking  29  at 10 cm (depicted in  FIG. 4  as a pair of printed bands) can be included on the first elongate medical device  10 , which is viewable as the device is being introduced into the duct  41 . The 10 cm mark  29  can be used for guidance to indicate that the first device  10  has been advanced a minimally ‘safe’ or sufficient distance into the duct, this occurring once the 10 cm mark  29  has disappeared from view, as shown in  FIG. 26   a - b . At this point, the endoscopic alignment indicators  84 , 85  are normally located within the viewable area  86 . In  FIG. 26   a , the first endoscopic alignment indicator  84  of the catheter is located proximal to the corresponding second endoscopic (wire guide) indicator  85 , indicating that the wire guide  11  is fully coupled to the first device  10  (i.e., completely traversing the coupling region). In the illustrative method, the operator utilizes the intermediate system of indicia  83  to determine when uncoupling of the devices  10 , 11  has occurred by advancing the first device  10  relative to the stationary wire guide  11  (which typically is locked down or secured against movement to maintain access within the duct), as shown in  FIG. 26   b . As the two indicators  84 , 85  become aligned, the distal end of the wire guide exits the proximal end of the coupling region or side access port (not shown) and uncoupling or disengagement takes place. As a further endoscopic indicator to prevent loss of wire guide access out of the duct during uncoupling, the distal portion  60  (e.g., the distal 6 cm) of the wire guide  11  can comprise a different coloration, such as black, so that it contrasts with the intermediate portion  97  (depicted in  FIG. 7 ). When the physician sees the black portion of the wire guide emerging from the papilla, the wire should be advanced back into the duct to minimize the risk of having to recannulate. If uncoupling has yet to take place and the distal black portion  60  of the wire guide is visible endoscopically, then both the wire guide  11  and tubular member  77  should be advanced further into the duct so that uncoupling can safely take place without risking loss of access. 
     An example of a non-visual system of alignment is depicted in  FIG. 40  in which the wire guide  11  includes a surface irregularity  160 , such as the illustrative bead, that is configured such that when it passes through the second end  75  of the coupling region  14 , e.g., through the side access port  15 , the operator feels or senses the contact between them, thus indicating that uncoupling is imminent with further repositioning. The illustrative side access port  15  is configured to include a flexible skirt  158  that includes an opening  159  sized to allow free passage of the wire guide  11 , but causing temporary resistance as the bead  160  passes therethrough. Furthermore, the skirt portion  158  can advantageously act as a seal to help prevent leakage of bile, blood, and air into the passageway of the tubular member. Other possibly surface irregularities include ridges, bumps, teeth, indentations, or a roughened portion that along with an appropriately configured side access port  15  or coupling region  14 , provide tactile feedback to the operator and thus, guidance to the state of alignment and engagement between the two devices. 
     Endoscopic devices used to perform medical procedures within the biliary system are typically divided into what could be called ‘primary access devices’, which typically comprise the initial device used in the procedure to cannulate the Spincter of Oddi and access the duct, and ‘secondary access devices’ for which the primary access device is exchanged to perform one or more operations within the work site. Examples of primary access devices of the present invention include sphincterotomes for ablating the sphincter to enlarge the opening to the duct (depicted in  FIGS. 10-11 ), needles knives (not shown), which are also used to cut the sphincter, and ERCP catheters ( FIGS. 4-5 ), which are adapted to infuse contrast media into the duct for radiographic imaging. Sphincterotomes and needles knives may also be configured to perform dual or multiple functions or operations, such as the infusion of contrast media and other agents. Some sphinctertomes include balloon used for sweeping the duct to remove calculi or stones lodged therein. Other devices, such as extraction balloons, may be used as both primary and secondary access devices. In pancreatobiliary procedures, primary access devices are exchanged for secondary access devices that are typically configured to perform a therapeutic function, such as to extract or crush stones, sample tissue, deliver radiation or light therapy, dilate or stent strictures (e.g., tumors), or place stents for drainage. If the secondary access device represents the last device used in a particular procedure, it need not be adapted for remote uncoupling, although it preferably would include at least a distal coupling region so the device can be advanced over a short wire without requiring an extension being added thereto. Generally speaking, virtually any secondary access device (extraction, dilation, or phototherapy balloons, dilator, forceps, brush, stent delivery catheter, brachytherapy catheter, lithotriptor, basket, snare, etc.) that is normally introduced into the biliary system over a wire can be adapted for remote uncoupling by the addition of a suitable coupling region within the distal portion of the device and preferably, but not necessarily, at least one of the three aforementioned systems of indicia to provide positive confirmation of uncoupling and relative alignment of the devices. 
     An exemplary method of using a primary access device (first elongate medical device  10 ), a wire guide  11 , and a secondary access device (third elongated medical device  44 ) of the present invention to access and perform a medical operation in a work site  41  is depicted in  FIGS. 9   a - f . The initial steps of the illustrative method include a standard endoscopic technique for accessing the biliary duct  41  to perform diagnostic and therapeutic procedures.  FIG. 9   a  shows a duodenoscope  38  that has been introduced via the oral cavity into the duodenum  39  to visualize the Papilla of Vater  40  and Sphincter of Oddi, which lie at the opening to the common bile duct  41  and the pancreatic duct. In the exemplary method, a dilator catheter  88  and wire guide  11  are advanced from the accessory channel of the scope  38  to cannulate a stricture  42  within the work site  41  (duct). It is general physician preference that determines whether the wire guide  11  is advanced past the tip of the primary access device  10  to assist in cannulation or whether the distal end  25  of the wire guide is within the passageway  27  during this part of the procedure. As depicted in  FIG. 9   b , the dilator catheter  10  (or other secondary access device) is advanced over the wire guide  11  with the proximal portion of the wire guide exiting the side access port  15  and extending through the channel alongside the catheter so that both separately exit the accessory channel of the scope as depicted in  FIG. 12 . For applications where the size of the scope channel is restricted or other applications where there is limited room to accommodate both devices side by side, the catheter can be modified to allow for the wire guide to lie alongside without increasing the overall diameter. This can be done by forming an open channel (preferably one that would not capture the wire) or creating a flattened longitudinal portion along the length of the catheter (not shown). 
     Still referring to  FIG. 12 , the proximal portion  59  of the wire guide  11  is typically, but not necessarily, secured in place once the distal end  25  thereof has been advanced to the desired position within the work site  41 . The illustrative wire guide holder  50  represents an improvement over prior art devices in that it is configured to be partially inserted into or over the opening  52  of the access port  51  to the accessory channel and provide a seal, rather than being secured elsewhere on the scope. The holder  50  further includes an optional integrated sealing element  65  having one or more types of seals, including duckbill, membrane with slit (e.g., polystyrene, silicone, or another compliant polymer material), foam seal with small central aperture (e.g., silicon, polyurethane, etc.), or other designs having the ability to seal around the catheter and wire guide to prevent any proximally migrating fluid from exiting the channel. The wire guide  11  is locked in place by interweaving it through a first series of spaces  53  (or channels, grooves, slots, etc) between spaced elements located along one side of a locking portion  66  of the device, such as the illustrative curved ‘spine’, using an alternating under/over manner as depicted. The illustrative holder includes three slots  53  or spaces on the first side and a second series of three slots  54  or spaces on the opposite side of the locking portion  66  to accommodate a second wire, if one is necessary for the procedure. 
     Unlike other wire guide exchange procedures where the proximal end of the wire guide is well out of the way of the physician, the short wires typically used in the illustrative remote uncoupling or ultra-short wire techniques usually result in the proximal end of the wire guide being within the physician&#39;s working area so that access thereto is readily available for introducing secondary devices to the work site. While the illustrative holder is configured to direct the proximal end portion of the wire guide downward and out of the way of the physician, the proximal end, when unsecured to feed another device over the wire, may deflect back up into the working area around the access port of the scope and can interfere with the physician during the procedure. To help alleviate this problem,  FIG. 7  depicts a wire guide  11  in which the proximal end portion  59  thereof is oriented at an angle  79  with respect to the distal and intermediate portions of the wire so that the proximal end  58 /proximal end portion  59  is typically oriented down and away from the operator (when rotated as such) and thus, out of the working area surrounding the access port of the endoscope while still allowing the physician to access the proximal end for the advancing the next device. In the illustrative embodiment, which comprises an 185 cm nitinol core wire guide  11  in which approximately 40-45 cm thereof typically is extending proximally out of the scope as the third elongate medical device is being advanced thereover, the bend  80  or point of deflection is preferably located about 20-30 cm from the proximal end, although the useful range may be anywhere from 0-50 cm. The useful angle  79  of deflection depends on physician preference, the configuration of the scope and wire guide holder, and other factors, but is generally about 30-120° for endoscopic procedures with a more preferred range of 45-90° for the illustrative embodiment. To create the bend  80  in a nitinol wire guide  11 , the material can either be heat set or mechanically overstressed (‘cold working’) to achieve the desired angle  79  of deflection and radius of the bend  80  (e.g., small, relatively acute bend or a large, more gradual or rounded bend). 
     Referring now to  FIG. 9   c , once the wire guide has been advanced to the desired location within the work site, the catheter is advanced or drawn back over the wire guide to position it for performing the intended operation. In the illustrative method, this involves the injection of contrast media  43  into the duct  41  to visualize the obstruction, which comprises a stricture  42  in this particular instance. Another common alternative approach to diagnosing potential obstructions in the ducts would be to initially introduce a sphincterotome  32  ( FIG. 10 ) to inject contrast media.  43 . If an obstruction is found, such as a stone, the sphincter might be ablated and a second device, such as a basket or balloon, is introduced over the original wire guide to extract the stone from the duct. A variety of other treatment possibilities exist and thus, it should be understood that the nature and sequence of the devices used is not critical to the present invention. 
     Once the initial operation has been concluded, the first elongate device  10  can be removed from the duct  41 . As depicted in  FIG. 9   d , the operator can conduct a device IDE by repositioning the distal ends of the ERCP catheter and wire guide  12 , 25  toward one another by advancing the catheter (as depicted), or preform a wire guide IDE by unlocking the wire guide  11  from the wire guide holder and drawing it back until the distal end  25  disengages from the catheter. Alternatively, the clinician can disengage or uncouple the device and wire guide  10 , 11  by moving both devices simultaneously until the wire guide exits the coupling region, typically keeping them within the work site  41  while uncoupling takes place. As discussed earlier, imagable indicia  18 , 26  on the distal portion  13  of the catheter  10  and the distal end  25  of the wire guide  1 , respectively, are utilized to confirm under fluoroscopy that disengagement or uncoupling has occurred, as shown in  FIG. 9   e . The proximal indicia  21 , depicted in  FIGS. 4 and 8 , and/or intermediate indicia  83  ( FIGS. 26   a - b ) may also be utilized to provide confirmation that uncoupling has taken place within the work site. This optional step is shown in  FIG. 12  in which the wire guide  11  is in the locked position  161  within the illustrative wire guide holder  50 , which is attached about the opening  52  of the biopsy port of the scope (over the rim of the port and/or inserted therein), is subsequently disengaged and placed in the unlocked position  162  adjacent the primary access device  10  so that the proximal indicia  21  of the two devices  10 , 11  can be aligned. As long as the proximal mark  37  of the wire guide  11  remains distal of the alignment mark  81  of the primary access device  10 , the operator knows that distal tip of the wire guide is still protruding from the distal end of the catheter within the duct (not shown). When the wire guide  11  is withdrawn (or primary device  10  advanced) such that the two marks  37 , 81  are in alignment, the operator knows the distal ends  12 , 25  of the two devices  10 ,  11  are generally aligned within the duct. As the operator continues to draw back the wire guide  11  or advance the catheter  10 , the alignment mark  37  becomes aligned with the disengagement mark  82 , which in the illustrative embodiment is indicative that the distal end of the wire guide has pulled completely out of the passageway or coupling area such that the two devices are uncoupled within the duct. 
     Once uncoupling has taken place, either device  10 , 11  becomes available as a conduit for introduction of a third elongate medical device to the work site. In the illustrative method depicted, the third elongate device  44  comprises a dilation catheter  88  ( FIG. 9   f ) that is introduced over the wire guide  11  by feeding the back end  58  of the wire guide  11  (not shown) into the distal opening  19  of the dilation catheter  88  and out of the side access port  15 , then advancing the dilation catheter  88  into the accessory channel of the scope, over the wire, and on into the duct  41 . Typically, the operator would choose to remove the first device  10 , if no longer needed, before introducing the third device  44 . This is done simply by having the operator pull the catheter out of the duct and scope channel in one continuous motion while maintaining the wire guide in position (e.g., such as locked within the wire guide holder  50  of  FIG. 12 ). Once the first device  10  is removed and the third device  44  is advanced to the work site, the second medical operation (e.g., dilation of the stricture) can be performed. If another operation is required, a third catheter-type device (fourth elongate medical device) can be advanced over the original wire guide  11  and so on. 
     As noted above, the present system of introducing and exchanging devices over a wire guide is adaptable such that a long wire guide can be introduced through a suitably configured medical device that has been introduced using the ultra-short wire method. In other instances, it may be desirable to convert an indwelling ultra-short wire to a longer wire for use with a non-compatible device.  FIG. 13  depicts a wire guide extender  56  for use with the present system to accommodate an external exchange with either a conventional medical device (‘long wire’) lacking the side access port for intraductal exchange, or conventional rapid exchange devices in which a somewhat longer external exchange (e.g., 30 cm) is required. In the illustrative system, the wire guide  11  includes a coupling mechanism  55 , such as a thread or wire loop, on the proximal end  58  that is configured to engage with a second coupler  57 , such as the illustrative hook, located on the distal end of the wire guide extender  56 . This effectively extends the length of the wire guide so that a conventional over-the-wire exchange can take place in the event that a particular device not designed for ultra-short wire exchange is to be used with the present system. One skilled in the art would readily appreciate the various types of coupling mechanisms that would be suitable to accomplish the extension of the wire guide for purposes of an exchange. They include locking or screw mechanisms, sheaths, bands, etc. that permit the two portions  11 , 56  to be joined temporarily or permanently. Another option is to use an adhesive strip or similar device to attach the wire guide  11  and extender  56  to one another. 
     The illustrative system of devices that allow for uncoupling within the work site and elimination of the external exchange over the wire can also be adapted for the introduction of second wire guide via an indwelling, uncoupled catheter into the work site, after placement of the first wire guide.  FIG. 10  depicts catheter  10  that includes a proximal access port  20  (third opening) located within the proximal portion of the catheter at a point that typically lies outside of the patient during a procedure (approximately 166 cm in the illustrative biliary device example). The proximal side access port  20  may include an optional sleeve cover that slides over and closes the access port when it is not in use. 
     To introduce a second wire  46 , the illustrative sphincterotome  32 , once disconnected from the first wire guide  11 , is not removed from the patient as in the method depicted in  FIGS. 9   a - f . Rather, the tip of the second wire guide  46  (third elongate medical device  44 ) is fed into the wire guide passageway  27  via the proximal opening  20  and advanced through the scope and into the duct  41 . In the example of  FIG. 11 , the first wire guide  11  resides in a first branch  48  of a bifurcation, such as where the common bile duct  41  branches into the two lobes of the liver. The sphincterotome  32  carrying the second wire guide can be rotated and deflected by the physician, by using the handle to pull back the cutting wire, to advantageously direct the advancing second wire guide into the opposite branch  49  such that each branch is now cannulated by the wire guide  46 . A sphincterotome  32  having a handle that provides axial rotation of the catheter body is preferable for orienting the distal cutting portion  33  into or toward the opposite duct for placement of the wire. Once the second wire  46  is in its desire location, it can be locked in place (e.g., using the second series of slots  54  of the illustrative wire holder  50  of  FIG. 12 ). After the sphincterotome or other primary access device  10  has been removed from the second wire  46 , both wires  11 , 46  are available for subsequent placement or introduction of additional devices, such as stents to restore or improve patency of the ducts. 
     Removal of the original catheter device  10  from the short second wire  46  requires that either an exchange must take place, such as by adding the wire guide extender  56  of  FIG. 13  to perform a long-wire exchange; or as illustrated in  FIG. 18 , the catheter may be peeled off of the wire  46  if the portion of the wire guide lumen  27  that lies between the distal (side) and proximal side access ports  15 , 20  is configured to allow the wire to laterally exit the passageway. This can be accomplished in a number of well-known ways including forming a weakness in the wall, such as making a score line, slit  67  or other pre-weakened area inside of the wall, such as that depicted in  FIG. 15 , or intermittent perforations formed partially or completely through the wall to weaken it longitudinally. 
     Alternatively, the tubular member can comprise an intact catheter wall that is configured to fail when sufficient lateral pressure is exerted by the wire guide residing in the passageway. One method of doing this is to make the wall  68  adjacent the wire guide lumen  27  sufficiently thin ( FIG. 16 ) and/or of a suitable polymer such that when lateral force is applied against the catheter, the wire guide  46  readily ruptures, splits or tears through the thin wall  68  as the catheter is being withdrawn from the patient.  FIG. 58  illustrates a portion of the catheter device  10  having a wall  68  adjacent the wire guide lumen  27  that is sufficiently thin so as to permit the wire guide  46  to readily rupture or tear through the thin wall  68  as the catheter  10  is being withdrawn from the patient. A material with a suitable molecular structure to encourage splitting, such as anisotropically oriented polymer, may be used or the polymer may be treated in some manner to facilitate or encourage splittability. Such a material, for example, may be selected or adapted to have a uniform rupture force so as to permit the wire guide  46  to be pulled through the wall  68  in a controlled manner along a pathway that is parallel to the longitudinal axis of the catheter shaft. In other words, the material may be selected or adapted to longitudinally rupture or tear in response to a constant and/or reduced pull force as applied to (or by) the wire guide.  FIG. 59  is a graphical representation of the pull force relative to the rupture distance from the port for a catheter comprising a standard shaft material (the upper line in the graph) as compared to a catheter comprising a shaft material specifically selected or adapted to have a reduced and uniform rupture force (the lower line ion the graph). In addition to facilitating or encouraging splittability, the material may be selected or adapted to reduce or eliminate jagged edges along the rupture path, as illustrated in  FIG. 58 . These jagged edges tend to collect bodily fluids and/or get caught on other medical devices. The entire catheter wall can be configured to facilitate splittability ( FIG. 16 ), or the splittable portion may be limited to one specific region along the circumference thereof such as including a longitudinal coextrusion of a second, lower durometer material extending to the outside of the wire guide lumen. 
       FIGS. 60-61  illustrate and embodiment of a catheter device comprising a coextruded shaft material, wherein the material surrounding the wire guide lumen is selected or adapted to facilitate splittability for removal of the wire guide. In particular, the catheter device  210  comprises a shaft  212  formed of a plurality of materials. The portion of the shaft  212  surrounding the wire guide lumen  214  is formed from a first material  216 , and the balance of the shaft  212  is formed from a second material  218 . In the embodiment illustrated, the first material  216  and the second material  218  comprise different materials having different physical properties. In particular, the first material  216  is selected or adapted to facilitate splittability as compared to the second material  218 . The first material  216  may also have a lower (or higher) durometer than the second material  218 . 
     A suitable coextruded catheter shaft  212  is manufactured by Zeus Industrial Products, Inc., 3737 Industrial Blvd., Orangeburg, S.C., as Zeus part numbers 89287 and 87943. Both of these part numbers identify a coextruded catheter shaft having a plurality of lumens, wherein the portion of the catheter shaft surrounding one of the lumens (e.g., the wire guide lumen) consists of a first material  216  comprising Zeus material component number 46108, and the balance of the catheter shaft consists of a second material  218  comprising Zeus PFTFE material component number 13129. The splittability of Zeus material component number 46108 is greater than that of Zeus PTFE material component number 13129. In particular, Zeus material component number 46108 has a reduced rupture pull force as compared to Zeus PIPE material component number 13129. Moreover, Zeus material component number 46108 has a more uniform rupture pull force as compared to Zeus PTFE material component number 13129. As illustrated in  FIG. 61 , Zeus material component number 46108 also tends to rupture or tear along a pathway that is parallel to the longitudinal axis of the catheter shaft  212 , and generally does not result in the formation of jagged edges. 
     In the embodiment illustrated in  FIGS. 60-61 , the first material  216  and the second material  218  comprise different materials having different physical properties. However, in the alternative, the first material  216  and the second material  218  may comprise the same material that has been modified, processed or otherwise altered so as to cause the material to have different functional properties within different portions or areas of the catheter shaft. For example, catheter shaft  212  could be manufactured from a single, uniform material. The portion of the shaft  212  surrounding the wire guide lumen  214  (i.e., area  216 ) could then be subjected to, for example, a chemical process that increases the splittability of the material. 
     In the embodiment illustrated in  FIGS. 60-61 , the first material  216  completely surrounds the wire guide lumen  214  and comprises approximately 25 percent of the total cross-sectional area of the catheter shaft  212 . More specifically, the cross-sectional area of the first material  216  is generally pie shaped and is configured such that removal of a wire guide from the wire guide lumen  214  will tend to rupture or tear the first material  216  along a pathway that does not intersect the second material  218 . In other words, the cross-sectional area of the first material  216  is configured such that removal of a wire guide from the wire guide lumen  214  will not compromise the integrity of the remaining portion (i.e., second material  218 ) of the catheter shaft  212 . 
       FIGS. 62-65  illustrate alternative embodiments of the catheter shaft  212  having different percentages and/or cross-sectional configurations of first material  216  and second material  218 . In the embodiment illustrated in  FIG. 62 , first material  216  comprises approximately 50 percent of the total cross-sectional area of the catheter shaft  212 , the balance of the shaft  212  comprising second material  218 . In the embodiment illustrated in  FIG. 63 , first material  216  comprises less than 20 percent of the total cross-sectional area of the catheter shaft  212 , the balance of the shaft  212  comprising second material  218 . In the embodiments illustrated in  FIGS. 64-65 , first material  216  does not completely surround wire guide lumen  214 , but instead only surrounds the outer half of the wire guide lumen  214 . 
       FIG. 66  illustrates and embodiment of a sphincterotome  220  comprising a coextruded catheter shaft  212  of the type illustrated in  FIGS. 60-61 . The catheter shaft  212  includes three lumens; a wire guide lumen  214  (see  FIG. 60 ), a cutting wire lumen, and a lumen adapted for the injection of contrast. The cutting wire  222  is exposed to the exterior of the catheter shaft  212  along the distal portion thereof, and extends proximally through the cutting wire lumen where it is connected to the handle  224 . Manipulation of the handle  224  causes the cutting wire  222  to move longitudinally relative to the catheter shaft  212 , which in turn causes the distal portion of the catheter shaft  212  to bow and assume a tissue cutting configuration. The cutting wire  222  is electrically connected via a connector  226  to an electrical source (not shown) for supplying electricity to the cutting wire  222  for performing an electro surgical procedure. An injection port  228  is disposed along the proximal portion of the catheter shaft  212  and provides fluid access to the lumen adapted for the injection of contrast. A proximal wire guide port  230  is also disposed along the proximal portion of the catheter shaft  212  and provides access to the wire guide lumen  214  ( FIG. 60 ). An intermediate wire guide port  232  is disposed along the catheter shaft  212  distally of the proximal wire guide port  230 . In the embodiment illustrated, the catheter shaft  212  has an approximate overall length of 200 cm, and the intermediate wire guide port  232  is located approximately 172 cm from the distal end of the catheter shaft  212 . Other features and details of the sphincterotome  220  are well known to those skilled in the art. As explained above in connection with the discussion of  FIGS. 60-61 , the catheter shaft  212  comprises a splittable material  216  surrounding the wire guide lumen  214 . Thus, a wire guide (not shown) exiting out of the intermediate wire guide port  232  can be removed from the wire guide lumen  214  by pulling the wire guide away from the catheter shaft  212  in a direction and with a force sufficient to rupture or tear the splittable material  216 . A radiopaque ban  234  may be disposed about the catheter shaft  212  a short distance (e.g., 6 cm) from the distal end of the catheter shaft  212  to prevent rupture of the catheter shaft  212  distally of the ban  234 . 
     As shown in  FIGS. 66   a - b , the intermediate wire guide port  232  may include a stress riser  240  to facilitate the initial rupture or tearing of the splittable material  216  in the portion of the catheter shaft wall  212  adjacent to the port  232 .  FIG. 66   a  is a perspective view of the portion of the catheter shaft  212  (see  FIG. 66 ) including intermediate wire guide port  232 , and  FIG. 66   b  is a top view of the intermediate wire guide port  232 . The design, construction and function of the stress riser  240  will be explained in greater detail below. The intermediate wire guide port  232  has a generally oval or elliptical shape that is formed by sciving material away from the side wall of the catheter to create an opening therethrough, the opening providing access to the wire guide lumen  214  from outside the catheter shaft  212 . The intermediate wire guide port  232  may also be formed by drilling or laser cutting through the side wall of the catheter shaft  212 . The dimensions of intermediate wire guide port  232  are generally sized to permit passage of the wire guide therethrough. For example, the width of the port  232  is preferably slightly larger than the diameter of the typical wire guide intended for use with the sphincterotome  220  so as to minimize frictional forces between the wire guide and the edge of the port  232  as the wire guide passes therethrough. Likewise, the length of the port  232  is preferably large enough to permit the wire guide to pass therethrough without causing excessive bending of the wire guide or catheter shaft  212 . 
     As shown in  FIGS. 66   a - b , the distal end  242  of the intermediate wire guide port  232  includes a stress riser  240  in the shape of a V-shaped notch. A stress riser is a portion or area of an object where, due to the object&#39;s geometry, stress in the material is locally amplified above the “nominal” stress in the surrounding material. Depending on the magnitude of the stress riser, the locally amplified stress in the material may be several folds larger than the stress in the surrounding material. Stress risers often take the form of sharp inside corners along an object&#39;s exterior or perimeter. Usually, stress risers are identified and eliminated from an object so as to make the object more durable and less likely to fracture. For example, the amplified stress at an internal corner of an object may be reduced via the application of a fillet of material to increase the radius in the corner. The rounded shape of the proximal end  244  of the intermediate wire guide port  232  is an example of an area of the shaft wall  212  having a relatively small stress riser due to its relatively large radius. As a result, the proximal end  244  of the intermediate wire guide port  232  is relatively resistant to rupture or tearing. The distal end  242  of the intermediate wire guide port  232 , in contrast, has a relatively large stress riser by virtue of the presence of V-shaped notch  240 . This is because the distal most portion of the V-shaped notch  240  has a very small radius (or no radius at all in the case of a sharp internal corner). Thus, the distal end  242  of the intermediate wire guide port  232  is much less resistant to rupture or tearing. 
     In the context of the present invention, the stress riser, i.e., V-shaped notch  240 , reduces the amount of force necessary to initiate the rupture or tearing of the splittable material  216  as the wire guide is pulled out of the wire guide lumen  214  and through the catheter shaft wall  212 . In an exemplary procedure, and with reference to  FIG. 66   c , the wire guide  11  extends through the wire guide lumen  214  of the catheter shaft  212  and passes out through the intermediate wire guide port  232 . The user may elect to “peel” or remove the wire guide  11  out of the wire guide lumen  214  by pulling the wire guide  11  out through the catheter shaft wall  212 . To do this, the user grasps the portion of the wire guide  11  extending out of the intermediate wire guide port  232  and pulls the wire guide  11  in a distal direction so as to engage the distal end  242  of the port  232 . The user continues to pull the wire guide  11  distally, thereby applying a force that is sufficient to rupture or tear the catheter shaft wall  212  along fracture line  246  (i.e., at the distal end  242  of the port  232 ). As explained above, the presence of the stress riser  240  reduces the amount of force necessary to initially rupture or tear the catheter shaft wall  212 . Once the fracture line  246  has been initiated, then the distal end of the fracture line  246  becomes a stress riser for the unruptured (i.e., solid) portion of the catheter shaft wall  212  that is just distal to the fracture line  246 . Thus, continued movement of the wire guide  11  in a distal direction relative to the catheter shaft wall  212  will result in further rupturing of the shaft wall  212 . 
     In the particular embodiment illustrated in  FIGS. 66   a - c , the stress riser  240  comprises a V-shaped notch that is formed by cutting and removing a V-shaped piece of material from the shaft wall  212  along the distal end  242  of the port  232 . However, the stress riser  240  may comprise any number of sizes and shapes depending on the desired rupture characteristics of the catheter shaft wall  212 .  FIGS. 78-83  illustrate several examples of stress risers  240  that will reduce the force necessary to rupture the catheter shaft wall  212  at a location adjacent to the wire guide port  232 .  FIG. 78  illustrates a wire guide port  232  having a tear-drop shape wherein the v-shaped distal end forms a stress riser  240 .  FIG. 79  illustrates a generally oval shaped wire guide port  232  having a small opening at the distal end thereof wherein the small opening forms a stress riser  240 . The small opening is formed by drilling a hole through the side wall  212  of the catheter shaft at a location that is contiguous with the side port  232 . A small hole/opening will form a larger stress riser than a larger hole/opening because of it has a smaller radius compared to the radius of the larger hole/opening.  FIG. 80  illustrates a stress riser  240  that comprises a stepped configuration that is formed by a plurality of holes/openings of different (i.e., decreasing) sizes.  FIG. 81  illustrates a illustrates a generally oval shaped wire guide port  232  having a small cut or slot through the shaft wall  212  at the distal end of the port  232 . The cut or slot forms a relatively larger stress riser  240  as compared to those illustrated in  FIGS. 79-80 .  FIG. 82  illustrates a wire guide port  232  having stress riser  240  in the form of a v-shaped distal end.  FIG. 83  illustrates a marquee shaped wire guide port  232  having a stress riser  240  at both the proximal and distal ends of the port  232 . Providing a stress riser  240  at both ends of the port  232  allows a wire guide  11  to be peeled through the catheter shaft wall  212  in either a distal or proximal direction relative to the port  232 . Such an arrangement may be advantageous when the port  232  is located along the distal portion of the catheter shaft  212 , or where a plurality of ports  232  is provided along the catheter shaft  212  at spaced apart locations. 
     Although the stress riser  240  has been described above in connection with a co-extruded catheter shaft  212  having a splittable material  216  adjacent to the wire guide lumen  214 , it should be understood that the stress riser  240  can be used with catheter shafts extruded from a single material or otherwise having a homogenous cross-section. For example, a stress riser can be provided for use with a catheter shaft having a score line or slit  67  extending through the wall (as depicted in  FIG. 150 , or having intermittent perforations formed partially or completely through the wall, or having a wire guide lumen positioned very close to the outer shaft wall (as depicted in  FIG. 16 ). Likewise, a stress riser can be utilized in a catheter that is not otherwise adapted to allow a wire guide to be pulled through the shaft wall. In other words, the addition of a stress riser may enable the shaft wall of any type of catheter to be ruptured to allow a wire guide to be pulled laterally out therethrough and separated from the catheter. 
     Although the embodiments of the coextruded catheter discussed above generally comprise a catheter shaft material surrounding or adjacent the wire guide lumen that is selected or adapted to facilitate splittability for removal of the wire guide, it should also be appreciated that catheter shaft materials having other physical properties may be chosen to provide the catheter shaft with other overall properties. For example, a material having an enhanced stiffness can be selected to improve the bending or torsional stiffness of the catheter shaft. A radiopaque material may be selected to provide the catheter shaft with radiopaque properties. A colored material may be selected to provide the catheter shaft with enhanced visibility. A translucent material may be selected to provide visibility of internal components, such as wire guides, within the catheter shaft. 
     It should also be appreciated that a catheter shaft comprising a plurality of materials may be formed by manufacturing techniques other than coextrusion. For example, a plurality of catheter shafts can be manufactured separately and then bonded together to form a unitary catheter shaft structure. Such a technique could be utilized to form a unitary catheter shaft structure having different properties along different longitudinally disposed portions of the catheter shaft. For example, a relatively short catheter shaft section comprised of a splittable material could be bonded to a longer catheter shaft section comprised of a less splittable material to provide an overall catheter shaft structure having a splittable portion along only a portion thereof. 
     As an alternative to (or in addition to) configuring the wall to increase splittability and/or including a stress riser to facilitate rupturing of the wall, a tab or other element can be attached or integrated into the catheter to facilitate manual splitting of the wall to remove the wire guide. A sharp tool or similar device represents yet another alternative method of accessing the guide wire lumen to separate the catheter from the wire. Another option is to extend the groove (see  FIG. 15 ) completely through the wall to form a narrow, open channel (see  FIG. 2 ) or a sealable or locking seam such that the two edges either are biased against one another or interlock by virtue of their complimentary structure. The seam is designed to split open or unlock when the lateral force supplied by pulling the wire guide there against is sufficient to force it open. 
       FIGS. 67-77  illustrate various peel tools  300  that can be used to facilitate or assist in the separation of the wire guide  46  from the catheter  10 .  FIG. 67  illustrates a peel tool  300  that is tubular in shape and configured to slide along the exterior of the catheter  10 . To separate the wire guide  46  from the catheter  10 , the user grasps and moves the peel tool  300  in a distal direction relative to the catheter  10  and/or wire guide  46 . As the distal end  302  of the peel tool  300  engages the portion of the wire guide  46  exiting from the side (or through the wall) of the catheter  10 , it imparts a force sufficient to separate these two components from each other. 
     The peel tool  300  may comprise any number of shapes or configurations.  FIG. 68  illustrates a peel tool  300  that is bullet shaped with a rounded and tapered distal end (or engagement portion)  302  that is less likely to damage the wire guide  46  as the wire guide  46  is pushed away from the catheter  10 ,  FIGS. 69-70  illustrate alternative peel tools  300  that comprise a longitudinal groove or channel  304  extending along one side thereof. The channel  304  engages the wire guide  46  and helps to align the wire guide  46  with the catheter  10  as these two components are separated. The central bore  306  of the peel tool  300  is sized to pass over the shaft of the catheter  10  (see  FIG. 68 ). The peel tool of  FIG. 69  is tapered with a larger diameter at the proximal end  302 , whereas the peel tool  300  of  FIG. 70  is tapered with a smaller diameter at the proximal end  302 . The selection of the shape and orientation of these various peel tools  300  is typically a matter of a user&#39;s individual preferences. 
       FIG. 71  illustrates another alternative peel tool  300  comprising a longitudinal slot  308  extending through one side of the peel tool  300 . The slot  308  extends to the central bore  306 . The slot  308  provides several advantages over the peel tools  300  described above. For example, the slot  308  permits the peel tool  300  to be clipped onto or removed from the catheter  10 . In addition, the slot  308  permits the peel tool  300  to moved past a first wire guide  46 ′ (exiting from proximal port  20 ) so as to engage a second wire guide  46 ″ (exiting from distal port  15 ). This is accomplished by rotating the peel tool  300  so as to align the slot  308  with first wire guide  46 ′. The peel tool  300  may then be moved distally past the first wire guide  46 ′ until it is adjacent the second wire guide  46 ″. The peel tool  300  is then rotated a sufficient amount to bring the slot  308  out of alignment with the second wire guide  46 ″. The peel tool  300  can then be used to engage and separate the second wire guide  46 ″ from the catheter  10 . 
       FIG. 72  illustrates a peel tool  300  that is connected to a wire guide holder  50  of the type shown in  FIG. 12  and described in detail above. In particular, this embodiment of the peel tool  300  comprises a curved member that is pivotally connected to the wire guide holder  50 . When not in use, the peel tool  300  is stored beneath and along side of the spine of the wire guide holder  50  so as to not interfere with the function of the wire guide holder  50 . To use the peel tool  300 , the peel tool  300  is pivoted to a position above and generally along side of the spine of the wire guide holder  50 . The distal end  302  of the peel tool  300  is then positioned between the catheter  10  and the wire guide  46 . While maintaining the peel tool  300  in this position, the user grasps and pulls the catheter  10  and guide wire  46  proximally, thereby causing these components to separate as they move past the peel tool  300 . The peel tool  300  may comprise a clip or locking mechanism that permits the peel tool  300  to be secured in either the stored or deployed position. 
       FIGS. 73-77  illustrate further alternative embodiments of the peel tool  300 . In these particular embodiments, the peel tool  300  comprises a separate component that is generally not mounted or attached to either the catheter  10  or the wire guide  46 . The peel tool  300  may, however, be supplied with the catheter  10  and/or wire guide  46  as part of a system of separate components. The peel tool  300  comprises an elongate member having a body portion  310  and an engagement portion  312 . As illustrated in  FIG. 73 , the body portion  310  is configured to be grasped by a user, and may include surface structures  314  that provide the user with a non-slip or tactile sensation. For example, the surface structures  314  may comprise a rubberized pad ( FIG. 74 ), transverse ridges ( FIG. 75 ), bumps ( FIG. 76 ), longitudinal grooves ( FIG. 77 ), or any other material or feature that decreases slipping or improves the ability of the user to grasp and manipulate the peel tool  300 . The body portion  310  may comprise any number of cross-sectional shapes or sizes. For example, the body portion  310  may be flat, circular, or tubular in shape. 
     As best seen in  FIG. 73 , the engagement portion  312  of the peel tool  300  is configured to engage the gap between the catheter  10  and wire guide  46  just proximal of the point where these two components separate from each other. To prevent the peel tool  300  from slipping out of engagement with the catheter  10  and/or wire guide  46 , the engagement portion  312  comprises one or more indentations or grooves  316  that are configured to engage and slide along the exterior surface of the catheter  10  and/or wire guide  46 . The grooves  316  may be any size or shape. For example, the grooves  318  may be “U”-shaped ( FIGS. 73-74 ), “V”-shaped ( FIG. 75 ), or “C”-shaped ( FIG. 76 ). In the embodiment illustrated in  FIG. 76 , the “C”-shaped groove is configured to snap or clip onto the catheter  10  and wire guide  46 . In the embodiment illustrated in  FIG. 77 , the engagement portion  312  comprises a “U”-shaped groove  316  configured to engage the wire guide  46 , and a circular opening  318  configured to surround and slide along the catheter  10 . 
     Returning now to the IDE method depicted in  FIGS. 9   a - f , it has been noted that the friction encountered when introducing a primary access device and a coupled wire guide through the accessory channel of an endoscope can, in some instances, cause premature disengagement of the two device before they reach the work site.  FIGS. 23-25  depict different embodiments of an elongate engagement member  89  which is configured to releasably secure the wire guide  11  to the tubular member  77 , such that unwanted disengagement or relative movement does not occur as the devices are being introduced or manipulated within the patient. In  FIG. 23 , the elongate engagement member comprises a wire stop member  90  preferably made of a flexible polymeric material with adequate column strength, such as nylon, which is similar in configuration to a standard pusher member. Preferably, the wire stop member  90  comprises a diameter (e.g., 0.035″) that substantially fills the inner diameter of the passageway  27  of the tubular member  77  such that when fully advanced to a point distal to the side access port  15  where the wire guide  11  enters the coupling region  14  (passageway  31 ), the wire stop member contacts and wedges the wire guide  11  against the inner wall of the passageway, thereby substantially preventing longitudinal movement of the wire guide  11  relative to the tubular member  77 .  FIG. 23  illustrates the wire stop member  90  disposed within a single-lumen tubular member  77 ; however, it may be used in multi-lumen device (e.g., a sphincterotome) as well.  FIG. 24  depicts the proximal hub  92  (a male luer fitting) of the wire stop member  90  in a retracted position  94  in which the wire stop member  90  is not sufficiently advanced to engage and lock or wedge the wire guide  11  within the passageway  27  a region or point  91  just distal to the side access port  15 . To do so, the proximal hub  92  is advanced to a forward position  95  in which the hub  92  contacts and engages the proximal (female) fitting  93  located at the proximal access port  23  of the primary access device  10 . Once the operator wishes to reposition the two devices  10 , 11  relative to one another, the proximal (male) hub  92  is disengaged from the female proximal hub  93  and drawn back until the wire guide  11  is released. Preferably, but not necessarily, the wire stop member  90  is removable from the passageway  27  such that agents, additional wire guides, etc., may be introduced therethrough. An elongate engagement member  89  is typically not used with a secondary access device insomuch that the wire is already indwelling within the work site and the need to secure the wire guide to the device is unnecessary. 
     A second embodiment of an elongate engagement member  89 , depicted in  FIG. 25 , comprises a thread-like snare member  96  made of suture, wire, cable, or other stand of material which loops around, ensnares, or otherwise releasably engages the wire guide within the passageway  27 . The snare member  96  can be attached to an actuating portion of the handle to give the operator sufficient control over its operation. When the operator wishes to disengage the wire guide  11  from the tubular member  77 , tension is released on the snare member  96 , or it can be cut or one end released so that it can be withdrawn from the passageway  27 . Alternatively, the snare member  96  can be disposed on the outside of the tubular member  77  to releasably engage and secure the wire guide  11 . The depicted embodiments represent but two possible types of devices adapted for securing the first elongate medical device  10  and wire guide  11  so that they can be co-introduced through a channel without disengaging therein. 
     The elongate engagement member  89  embodiments of  FIGS. 31 and 32  also include the coupling region  14  of the device  10  that may be configured to be partially retractable back into the secondary passageway  115 . This action creates a frictional engagement with the wire guide such that the elongate engagement member  89  further acts as a stop to prevent the wire guide  11  from sliding freely within the coupling region  14 . 
     The present invention and method includes using devices in procedures where once the primary access device is used within the work site, a secondary access device is introduced over the guiding device (wire guide) which has been uncoupled from the primary device within the work site. In the biliary tree, a number of possible devices may be introduced to perform a variety of medical procedures, a few selected examples of which are depicted in  FIGS. 9F ,  14 ,  17 ,  19 - 22 ,  27 - 28 ,  39 ,  41 - 44 ,  51 , and  53 . The exemplary devices are certainly not representative of all secondary access devices appropriate for use in the biliary tree, nor is their use particularly limited to being a secondary device used following a primary device. The illustrative devices depict some of the general types of medical devices used endoscopically in the biliary tree, as well as other non-biliary and non-endoscopic procedures performed elsewhere in the body. 
       FIG. 17  depicts a system for delivering a biliary or pancreatic drainage stent  69  mounted on a delivery catheter  110  (elongate medical device  10 ) of the present invention. The illustrative COTTON-LEUNG® Biliary Stent (Wilson-Cook, Medical Inc.) is mounted on an OASIS® One Action Stent Delivery System (Wilson-Cook Medical, Inc.), modified for IDE, which extends through the internal lumen  72  of the stent  69 , which is slidably mounted thereover (when used with a pusher member  101  (see  FIGS. 29   a - c ). It should be noted that the illustrative stent delivery catheter  10  is configured to accept different kinds of tubular drainage stents in addition to the type shown. The coupling portion  14  of the delivery catheter  110  comprises the passageway  27  between the distal opening  19  and the side access port  15 , which is located 1.5-2.0 cm from the distal tip. A proximal marking  18 , such as the illustrative iridium band, is located at about 1 cm, just distal to the access port  15 . The wire guide  11  exits the side access port  15  at a point distal to the distal end  71  of the stent  69  to advantageously provide a means for withdrawing the stent  69  along with the delivery catheter  110 , which greatly assists in the ability to reposition the stent within the duct. When the catheter  10  and wire guide  11  are withdrawn together relative to the stent (which is held stationary by the pusher member), the distal edge  71  of the stent  69 , which is slidably positioned over the catheter, lodges in a triangular wedge point  70  formed by the junction of the delivery catheter and the wire exiting therefrom. Thus, the stent  69  is pulled backward along with the delivery catheter, providing the clinician with a simple and reliable means to pull the stent partially out of the duct so that the proximal anchor flaps  73  can extend outside of the duct, if so desired. Once positioned at the desired location, the wire guide  11  and delivery catheter  110  are uncoupled and the latter is withdrawn from the lumen  72  of the stent  69 . In delivery systems in which the wire guide  11  extends through the lumen  72  of the stent  69 , pulling back on the delivery catheter  110  would not allow the clinician to pull the stent back with it without an additional mechanism to releasably couple the stent to the delivery catheter. It should be noted that this method can be readily adapted for other stent designs as well, particularly other non-expandable tubular stents and those having pusher members. 
     The illustrative stent delivery system of  FIG. 17  is particularly well-adapted for placement of multiple stents as depicted in the method of  FIGS. 29   a - e , insomuch that remote uncoupling of the wire guide  11  and apparatus  10  can be performed within the duct, unlike previous biliary stent delivery systems, thereby eliminating the need for recannulating the papilla for each stent placed. As depicted in  FIG. 29   a , the inner delivery member  10 , which is coupled to the wire guide  11 , is advanced out of the endoscope  38 , through the ampullary orifice  40  and into the duct  41 . The wire guide  11  does not extend through the lumen of the stent  69  and pusher member, which is not yet shown. In  FIG. 29   b , the pusher member  101  urges the stent over the inner member  110  until the distal end  71  thereof reaches the junction  70  formed where the wire guide  11  exits the side access port (alternatively, the inner member  110  and stent  69  can be pulled back while the pusher member  101  contacts the stent and causes it to advance further up over the inner member  110 ). As noted above, the junction  70  can be used to contact the distal end  71  of the stent and pull back or reposition the stent  69 , such as when it had been advanced too far into the duct for ideal deployment. Once the stent  69  is in the proper position for deployment, as depicted in  FIG. 29   c , the inner member  110  is advanced further into the duct  41  so that there is sufficient room for the uncoupling procedure to take place. The wire guide  11  is unlocked from the wire guide holder  50  (see  FIG. 12 ) and pulled back until it exits the side access port  15 , as depicted in  FIG. 29   d . The inner member  110  is then withdrawn through the stent  69 , along with the pusher member  101 , and removed from the channel of the endoscope. The wire guide  11  is then re-advanced further into the duct to serve as a conduit for the next stent delivery system, shown in  FIG. 29   e , such that a second stent  109  can be deployed alongside the first in the manner shown in  FIGS. 29   a - d . Subsequent deployments of additional stents can be also be made using the same technique over the original wire guide. 
     Other stent or prosthesis delivery systems configured for use with the present invention are depicted in  FIGS. 22 ,  27 , and  39 .  FIG. 22  depicts a delivery system  99  for a self-expanding prosthesis  98 , which could include a self-expanding stent, such as the Wilson-Cook ZILVER™ Biliary Self-Expanding Stent or any nitinol, stainless steel, or other self-expanding stent; artificial valve (e.g., venous, heart, pulmonary, etc.) prosthesis, vessel occluder, filter, embolic protection device, shunt, stent graft, etc. The illustrative apparatus comprises an inner member (elongate medical device  10 ) on which the prosthesis  98  is mounted and an outer member  100  or sheath which constrains the self-expanding prosthesis  98  until deployment. The side access port  15  is located about 3 cm from the distal tip  12  of the inner member  10  with the coupling region  14  being completely distal to the prosthesis  98 . 
     An alternative system for deploying a self-expanding prosthesis is depicted in  FIG. 39  which includes a series of corresponding slots in the inner and outer members  10 , 100  to allow for relative repositioning during deployment (the sheath  100  typically being drawn back while the inner member  10  of the delivery system is maintained in position). This permits the coupling region  14  to extend through the prosthesis  98  and allow the wire guide  11  to exit the side access port  15  proximal to the prosthesis  98 , which would allow the wire guide to reside inside and be deployed inside prosthesis  98 , and as a result, less chance of losing access to the work site. This may be especially advantageous in deployment of stents, other prostheses, and other ancillary devices, such as dilation balloons, within the vascular system in that recannulation through the deployed stent may be problematic, possibly leading to complications such as dislodgement or catching on the deployed stent, dislodgement of plaque, etc. With regard to placement of artificial venous and other types of artificial valves, maintaining wire guide access through the valve may be particularly advantageous in that recannulation through the leaflets or valve structure to deploy additional valves or introduce a seating balloon to fully expand the valve support frame against the walls of the vessel may prove particularly difficult, possibly leading to damage of delicate leaf structure and compromise of valve function. 
       FIG. 27  depicts an endoscopic biliary stent  69  and pusher apparatus  101  (typically 5.0-7.0 FR) which is configured for ultra-short wire and rapid exchange use. It primarily differs from the embodiment of  FIG. 17  in that it lacks the inner member. Both the stent  69  and pusher member  101  (the elongate medical device  10  in this particular embodiment) are introduced through an outer introducer member  100 , where the distal end  12  of the pusher apparatus  101 , which includes the coupling region  14  about its distal portion  13 , urges the stent forward for deployment within the duct. The side access port  15  is located about 6 cm from the distal end  12  of the pusher member  101  (elongate medical device  10 ) such that the wire guide traverses the passageway of the stent  69 . 
       FIGS. 41-42  depict another embodiment in which the stent  69  comprises a pigtail drainage stent  126 , such as the illustrative naso-biliary drainage stent, that includes a curved anchor portion  127  in the deployed configuration  128  ( FIG. 41 ) that is configured to assume a straightened configuration  129  when placed over a wire guide  11  for introduction into the bile duct, as shown in  FIG. 42 . Preferably, but not necessarily, the drainage holes  130  disposed along the distal portion of the stent  126  are sized such that the wire guide  11  cannot readily exit therethrough (e.g., 0.025″), whereas the side access port  15  is sized to easily accommodate the exiting wire guide (e.g., 0.035″ or larger). In the illustrative naso-biliary embodiment, there are five drainage holes distributed about 6 mm apart along the distal portion  13  distal to the side access port  15  and marker band  18 . In this particular embodiment, there is a series of optional drainage holes  130  proximal to the side access port  15  as well. The spacing of the drainage holes can vary according to the diameter of the curl, generally ranging from 5 mm to 1 cm or more. As the wire guide  11  is repositioned relative to the stent  126  to perform an intraductal exchange, the anchoring portion  127  recoils into its intended shape when the wire guide is no longer inside the coupling region passageway  31 . The illustrative embodiment could also be adapted for use as a naso-pancreatic drainage stent, ureteral or urethral stent, or other stent having one or more curved or pigtailed end portions and various configurations of drainage holes. The illustrative embodiment of  FIG. 41  further includes an intermediate curved portion that allows the stent to better conform with the anatomy of the pancreatobiliary tract and duodenum into which it is placed. 
     Another embodiment of naso-biliary and naso-pancreatic drains is depicted in  FIG. 43  that is similar to the embodiment of  FIGS. 41-42 , except that it includes a pair of distal anchoring flaps  180  and lacks the pigtail anchoring portion. Furthermore, the side access port is preferably located closer to the distal end  12  of the device (e.g., about 2 cm vs. about 6 cm for the pigtail embodiment). Typically naso-biliary drains are 5-10 FR in diameter while the naso-pancreatic drains are 5-7 FR. Both the pigtail and non-pigtail drain embodiments may advantageously include a stiffening stylet (depicted in  FIG. 43 ) that extends to about the side access port  15  and provides pushability, as well as straightening out a loop or bend, if present, located proximal to the side access port. Such a bend may allow the device to conform to the anatomy of the patient, such as to better traverse the contours of the duodenum. An example of the bend or curved portion  172  is shown in  FIG. 41 . 
       FIGS. 19-20  depict balloon  47  embodiments of the present invention that are adapted for short wire use.  FIG. 19  comprises a dilation balloon  47  (a modified QUANTUM™ Biliary Balloon, Wilson-Cook Medical, Inc.), which is made of a non-compliant material (e.g., PET) such that balloon member  102  can be inflated to a predetermined diameter to dilate a stricture within the duct,  FIG. 20  comprises an extraction balloon  47 , such as a modified TRI-EX™ Triple Lumen Extraction Balloon (Wilson-Cook Medical, Inc.), which comprises a non-compliant material (latex, silicone, etc.) which is adapted for sweeping the duct of material, such as stones, sludge, etc. Both embodiments include a side access port  15  about 6 cm from the distal end  12  of the catheter  10  such that the coupling region  14  extends through the balloon member  102  and exits proximal thereto. The embodiment of  FIG. 20  further illustrates a removable stiffening stylet  103  that is maintained within the passageway  27  of the catheter member  10  to provide rigidity, especially across the side access port  15  (and optional proximal side access port, not shown) such that kinking is less likely to occur at that point. The stylet, preferably made of metal (e.g., stainless steel) or a relatively stiff plastic or other material, would not provide any engagement function similar to the distal wire lock  90  of  FIG. 23  in most applications since that would interfere with the ability to advance the device over the wire guide. 
       FIG. 21  depicts a biopsy device  104  for collecting cells within the biliary tree. The illustrative embodiment, which comprises a modified CytoMAX II™ Double Lumen Biliary Brush (Wilson-Cook Medical, Inc.), includes a side access port  15  about 6 cm from the distal end  12  of the tubular portion  77  of the device  10  and a brush element  105  disposed about the distal end and extending beyond such that the coupling region  14  terminates proximal of the brush element  105 , the distal opening  19  for the wire guide  11  being disposed about the distal end of the tubular member  77  about the base of the brush element  105 . An alternative device for delivering a biopsy device  104  or other device within a work site is depicted in  FIG. 38 . The illustrative tubular member  77  includes a standard coupling region  14  about the distal end except that the passageway  27  of the tubular member, rather than communicating with the passageway  31  of the coupling region  14 , terminates about a ramped external opening  122  that is configured to accommodate a separate elongate medical device for introduction to the work site which is not directly coupled to the wire guide  11 . The illustrative biopsy device  104  can be advanced to gather a tissue sample, then withdrawn back into the passageway  27  and either removed from the patient with the introducing member  77 , or removed therefrom and a second medical device advanced into the passageway to perform a different procedure. In addition to the radiopaque marker band  18  to indicate the location of the second end of the coupling region  14 , the illustrative tubular member includes an additional marker  123  located about the ramped opening which provides additional guidance to the operator. The illustrative biopsy device is but one example of a device deliverable in the manner shown in  FIG. 38 . 
     Another secondary access device is depicted in  FIG. 28 , which comprises a brachytherapy or radioactive seed delivery catheter  106  which includes a passageway  27  for the wire guide  11  (and which includes the coupling region  14 ) and second, closed-ended passageway  107  for receiving a radioactive element  108 , such as a catheter, stylet, or individual radioactive seeds that are introduced thereinto. The brachytherapy device  106  is introduced over the wire guide  11  to the treatment site, where it is positioned for a period of time sufficient to deliver an effective therapeutic dose of radiation to adjacent tissue, such as a tumor within the biliary tree. Typically, the side access port  15  is located about 6 cm from the tip which is preferably made of a pliable, atraumatic polymer material. The second passageway is preferably located centrally so that radiation is dispersed evenly in all directions. As a result, the first wire guide passageway may either terminate distal thereto, about the side access port  15 , or be offset therefrom, at least becoming so at a point proximal to the side access port  15  and coupling region  14 . 
       FIGS. 44-57  depict a series of non-biliary devices configured for introduction through the patient&#39;s mouth, rather than through the accessory channel of a duodenoscope, such as the aforementioned embodiments. Placement of the embodiments of  FIGS. 44-57  typically involves using an ultra-short wire guide  11  that is advanced to the treatment site by being coupled to the outside of an endoscope. The wire guide is then uncoupled from the scope and locked in place to serve as a pathway for the introduction of other devices, such as within the esophagus or elsewhere within the gastrointestinal tract. Optionally, the wire guide  11  ( FIG. 57 ) can include a hydrophilic or otherwise lubricious coating or surface  173  (e.g., SLIP-COAT® Biopolymer, STS Biopolymers, Inc., Henrietta N.Y.) to facilitate the advancement of devices thereover after the wire guide has been placed. The coating is advantageously restricted to a portion of the wire guide  11 , such as the intermediate portion  97 , with the proximal portion  59  that extends out of the patient and is manipulated and locked by the operation (e.g., the proximal 10-15 cm) having a standard non-hydrophilic surface (e.g., PTFE) to make it easier to secure the wire guide in place. The distal portion  60  (e.g., 2-6 cm) of the wire guide may also be left uncoated to give the operator a better degree of control to help avoid accidental, premature uncoupling of the wire guide from the coupling region of the devices being advanced thereover. The lubricious intermediate portion  97  of the illustrative wire guide of  FIG. 57  is especially advantageous when used in the small or colon to allow the device to slide more easily therewithin, while still allowing the wire to be secured at each end by the bite block and distal loop  144 , respectively. 
       FIGS. 44 and 45  depict a dilator catheter  88  and wire guide  11  comprising a system for dilating strictures within the esophagus. The dilator  88  includes a system of scale indicia  133  located about the proximal portion of the tubular member. In the illustrative embodiment, which is about 75 cm in length, indicia are located to indicate the 40, 50, and 60 cm mark to help align the device with the indwelling wire guide  11 , which includes a similar series of indicia  134 , such as the illustrative bands that increase in number at each 10 cm interval to indicate the distance from a reference point. The alignment indicia  133 , 134  advantageously permit accurate positioning of the device at the treatment site, such as the GE (gastroesophageal) junction, a stricture, or other site that is to be dilated, irradiated, or otherwise treated, after the treatment site has been confirmed using the endoscope used to carry the wire guide thereto. 
     A method for introducing the wire guide  11  and dilator catheter  88  of  FIGS. 44 and 45  into the esophagus to perform a series of esophageal dilations using successively larger dilator catheters is depicted in  FIGS. 55   a - f . The basic method can also be used for introducing other devices that are too large to be introduced through an accessory channel of an endoscope or where standard endoscopic placement techniques either are not appropriate or not possible. As shown in  FIG. 55   a , the wire guide  11  is carried to the work site using an endoscope  38  and a wire guide carrying mechanism  174 , which in the illustrative embodiment comprises the endoscopic wire guide holder  140  depicted in  FIG. 48 , which resides within the accessory channel  165  of the scope and includes a mechanism to couple with the wire guide  11  via a distal loop  144  about the distal end  25  thereof. As shown, the endoscopic wire guide holder  140  comprises a catheter portion having a lateral recess  142  proximate the distal end  12  thereof and a longitudinal slidable pin member  141 , disposed within a passageway  145  in the shaft  146  of wire guide holder  140 , that is adapted to traverse the distal loop  144  of the wire guide. The pin member  141  is advanced to secure the loop  144  within the recess  142  to carry the wire guide  11 , which is at least substantially outside of the scope accessory channel  165 , down to the work site, where it is released by the operator by actuating the finger ring portion  148  of the handle  147  relative to the thumb ring  149  until the loop  144  slips off the retracting pin member  141 . When the pin  141  is fully advanced into a locking channel  143  that extends distally from the lateral recess  142 , the loop  144  is secured and cannot slip free. The endoscopic wire guide holder  140 , which is then withdrawn from the work site along with the endoscope, can either carry the wire guide  11  while partially extending from the accessory channel, or be withdrawn into the accessory channel  165  (as shown) such that the distal end  25  of the wire guide is pulled thereinto. 
     A second embodiment of a wire guide carrying mechanism  174  is depicted in  FIGS. 46-47  comprising a ring element  136  that attaches to the outside of the endoscope  38  about the distal end thereof using a friction fit, clamping mechanism, or some other well-known means, and is configured to releasably secure the wire guide  11  being carried to the work site. The wire guide  11  includes a detachable element  135 , such as the illustrative distal ball, which is crimped, glued, or otherwise fastened about the end  25  of the wire guide and designed to slide off or break apart with the application of a sufficient amount of pull force (e.g., 3 lbs.) and be safely passed through the gastrointestinal system or be absorbed thereby. The ball tip  135  is inserted into an open slot  137  in the ring  136  and then slipped laterally beneath a lip portion  138  and into a recess  139  that together, help secure the wire guide and allow it to be pulled along with the scope. With the ball  135  residing in the recess  139  formed along the distal edge of the ring, the wire guide  11  can be uncoupled from the scope  38  by pulling on the proximal portion of the wire guide while maintaining a counter force against the scope  38  to keep it in place. When the ball  135  is dislodged ( FIG. 45   a ), the wire guide  11  can slip under the lip portion  138  ( FIG. 47 ) and the endoscope  38  can be withdrawn from the patient, leaving the wire guide in place. 
     Referring again to  FIG. 55   a , the endoscope is typically positioned within the work site  41  just proximal to the specific site (sphincter, stricture, lesion, etc.) therein that is to be treated. In the illustrative method, the scope  38  is advanced to the GE junction  156  while depth markings located about the proximal portion of the scope exiting the patient (not shown) provide the operator with the distance from the mouth to the treatment site. At this point, the distal end  25  of the wire guide  11  is also generally positioned at the GE junction  156  since it is engaged proximate the distal end of the scope  38 . The endoscope  38  and wire guide are advanced through the esophagus  155  and positioned at the GE junction  156 , where that distance is noted. The operator may advance the scope  38  10 cm (or some other similar, predetermined distance), which places the distal end  25  well within the stomach  157  (about 10 cm past the GE junction  156 ). Or, as depicted in  FIG. 55   b , the operator may advance the wire guide holding device  140 , which may include proximal depth indicia as well, a similar distance beyond the scope  38  and into the stomach  157 . The wire guide  11  in the embodiments depicted in  FIGS. 45 and 50  include a reference mark  175  located 10 cm from the distal end  25  (or whatever distance the wire guide is to be advanced past the GE junction or other anatomical reference point). The wire guide  11  of the illustrative embodiment depicted in  FIG. 45  includes a series of proximal indicia  134  that can comprise varying numbers of markings at selected intervals therealong (e.g., 30, 35, 40, 45, 50, and 55 cm from the reference mark  175 ). In another embodiment depicted in  FIG. 50 , the wire guide includes five 5 cm bands  150  of different colors that span from the 30 cm mark to the 55 cm mark as measured from the reference mark  175  which is 10 cm from the tip  25 . The indicia  134  may further include 1 cm reference marks  177  (e.g., hash marks) within each colored band  150 . Preferably, the bands  150  of the embodiment of  FIG. 50  comprise colors that contrast with the adjacent band. For example, cool and warm colors may be advantageously placed adjacent one another to create a sequence such as yellow, green, red, blue, and then orange. 
     Once the wire guide  11  has been advanced 10 cm past the GE junction  156 , it is uncoupled from the wire guide carrying mechanism  174  and secured in place by some means such as using the illustrative bite block  151  depicted in  FIG. 52  with integral wire guide securing portion  154 , and which includes straps  153  that secure the bite block  151  around the patient&#39;s head. In addition to functioning as a mechanism  50  for securing the wire guide in place, it also maintains an open working area  152  through which the scope, wire guide  11 , and primary or secondary devices are passed to the work site. 
     In instances where a narrow stricture exists that cannot accommodate the scope without risking creating a tear in the esophagus (at least without being properly dilated beforehand), the wire guide holding device  140  advantageously provides a means to safely advance through and traverse the stricture to carry the wire therebeyond and serve as a pathway for advancing the dilators, the smallest of which may be less than the scope diameter. 
     Now referring to  FIG. 55   c , the endoscope  38  and wire guide holding device  140  are typically withdrawn from the work site  41  such that the primary access device  10 , which in the illustrative method comprises a first dilator  167 , can be advanced over the wire guide  11  to perform a medical operation, as depicted in  FIG. 55   d . To advance the first dilator  167 , the wire guide  11  is temporarily unlocked from the holding device so that the proximal end thereof can be threaded through the coupling region  14  of the dilator. Alternatively, the primary device  10  (e.g., dilator  167 ) can be coupled to the wire guide  11  prior to the wire guide being advanced to the work site  41 . The illustrative dilator  167  includes optional radiopaque marker bands  18 , 132  located at the side access port  15  and distal edge of the widest portion of the device before the tapered end, respectively. While it is the GE junction that is established as the anatomical reference point to which the illustrative wire guide  11  and primary access device  10  are aligned, the region of the esophagus having the stricture to be dilated may lie anywhere proximal to the GE junction. Reference to the GE junction is preferred to provide a consistent known distance within the stomach for uncoupling. 
     The dilator  167  ( FIG. 44 ) also preferably includes a series of proximal indicia  133  as well that are aligned with the wire guide indicia  134  so that the operator can determine when a particular point along the dilator (e.g., distal end of the widest portion  132 , distal tip  12 , side access port  15 , etc.) has reached the GE junction, the tip of the wire guide, or some other reference point. 
     Once the first dilator  167  has been advanced past the esophageal stricture or the GE junction  156  as the first step of enlarging the opening thereof, the distal portion  13  is advanced fully into the stomach  157  of the patient so that uncoupling can occur, as depicted in  FIG. 55   e . Typically, this is accomplished by advancing the side access port  15  past the distal end  25  of the wire guide  11 , which remains locked in place, until the distal end  25  thereof slides free of the coupling region  14 . As with the biliary techniques depicted in  FIGS. 9   a - f  and  29   a - e , the uncoupled primary access device  10  is then removed from the patient and a secondary access device (third elongate medical device  44 ) such as second (larger) dilator  168 , is introduced to the work site  41  as depicted in  FIG. 55   f . Esophageal dilations typically involve passage of a series of progressively larger dilators, although one or more of the smaller sizes may be skipped if resistance is not felt during the initial dilation. 
     An alternate embodiment of a dilator catheter  167  is shown in  FIG. 56  in which the side access port  15  is located on a proximally facing surface or plane  169  formed as the distal (larger) diameter portion  170  of the dilator transitions down to the smaller, proximal portion  171 . This advantageously eliminates having the wire guide  11  lying alongside the widest part of the dilator  167  during passage of both through the stricture. The illustrative stepped configuration can also be useful in other embodiments of the present invention to eliminate friction caused by a wire guide passing within a sheath or channel, such as within an endoscope. 
     The general method of  FIGS. 55   a - f  can also be adapted for placement of other devices outside of the endoscope, such as a photodynamic therapy (PDT) balloon  47 , depicted in  FIG. 51 , or an achalasia balloon  53 , depicted in  FIG. 53 . Both devices depicted are commercially available from Wilson-Cook Medical, Inc. and shown herein as modified for ultra short wire delivery. Positioning of the PDT balloon  47  is performed by using the endoscope to locate the GE junction and place the wire guide  11  at a suitable, known distance therebeyond, such as 10 cm, that distance corresponding to the reference (or ‘zero’) mark  175  of the wire guide. In the illustrative embodiment of  FIGS. 50-52 , the wire guide includes colored bands  150  that correspond to those comprising the proximal indicia  133  of the PDT balloon catheter  47  such that when the colors are aligned ( FIG. 52 ), the reference point  176  of the device  10 , which in the case of the PDT balloon, is the distal edge of the light-emitting portion  178  of the balloon member  102 , is located at the GE junction. This places the light-emitting portion  178  at the optimal location to treat the disease (e.g., Barrett&#39;s esophagus). It should be noted that the colored bands  150  or other indicia  133 , 134  of the illustrative embodiments are configured for aligning the treatment device  10  with the wire guide  11  and thus, the site selected for treatment and may or may not have other functions such as to aid in the alignment of the tips  12 , 25  of the device with one another or with the side access port  15  to indicate that uncoupling is imminent. Separate indicia may be used for alignment relating to coupling and uncoupling. While the colored bands  150  of the wire guide  11  are configured to refer back to the reference mark  175  that corresponds (in this embodiment) to the GE junction, the colored bands  150  of the primary access device  10  are configured such that alignment with those of the wire guide places the device in the correct position for treating the disease. Thus, they are not necessarily (and usually are not) of the same reference scale. 
       FIG. 53  depicts an embodiment in which the primary access device  10  comprises an achalasia balloon. With the treatment of achalasia differing in that the balloon is placed across the GE junction rather than proximal thereto, the reference point  176  that corresponds to the proximal reference indicia (not shown) and permits the device to be aligned with the GE junction, is located at the center of the balloon member  102  rather than the distal edge as in the PDT balloon. 
     The technique of dragging the wire guide outside of the scope to the work site, uncoupling it, and advancing a device thereover, is also applicable to a number a larger diameter catheters ( FIG. 54 ), such as feeding tubes (e.g., nasojejunal, nasoenteric, etc.) which are advanced via the mouth into the stomach or small intestines for placement. These catheters may advantageously include a stiffening stylet  103  in the passageway  27  to prevent the scope from dragging the catheter device  10  with it as it is being backed out of the work site, which in turn, could cause the wire guide  11 , which is typically locked in place, to pull out of the coupling region  14 . The stiffening stylet  103  is removed prior to or after the devices are uncoupled using radiographic, endoscopic, and/or proximally visible indicia located on the two devices  10 , 11 . 
     While the gastrointestinal tract may at present provide the most obvious anatomical sites for practicing the methods and techniques of the present invention, further changes in interventional medicine may bring about increasing opportunities where remote uncoupling and ultra-short wire techniques may offer a viable alternative to traditional rapid exchange or other current techniques. For example, many common urological procedures were preformed using wire guide exchange until the introduction of videoendoscopes ideal for urological use. This resulted in direct visualization becoming the standard methodology for manipulating and placing devices in the urological tract. Future developments and improvement in external visualization methodology may result in a return to wire guided procedures where remote uncoupling offers a true advantage to the urologist. Similar advancements in other specialties, especially in vascular and coronary medicine, may create situations where the potential benefits of remotely uncoupling may be realized. 
     Any other undisclosed or incidental details of the construction or composition of the various elements of the disclosed embodiment of the present invention or methods of their use are not believed to be critical to the achievement of the advantages of the present invention, so long as the elements possess the attributes needed for them to perform as disclosed. The selection of these and other details of construction are believed to be well within the ability of one of even rudimentary skills in this area, in view of the present disclosure. Illustrative embodiments of the present invention have been described in considerable detail for the purpose of disclosing a practical, operative structure whereby the invention may be practiced advantageously. The designs and methods described herein are intended to be exemplary only. The novel characteristics of the invention may be incorporated in other structural forms without departing from the spirit and scope of the invention. The invention encompasses embodiments both comprising and consisting of the elements and steps described with reference to the illustrative embodiments. Unless otherwise indicated, all ordinary words and terms used herein shall take their customary meaning as defined in The New Shorter Oxford English Dictionary, 1993 edition. All technical terms shall take on their customary meaning as established by the appropriate technical discipline utilized by those normally skilled in that particular art area. All medical terms shall take their meaning as defined by Stedman&#39;s Medical Dictionary, 27th edition.