Patent Publication Number: US-2022226016-A1

Title: Material removal from within a patient

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/US2020/052594, titled MATERIAL REMOVAL FROM WITHIN A PATIENT, filed on Sep. 24, 2020, which claims priority to U.S. Provisional Patent Application No. 62/905,369, titled MATERIAL REMOVAL FROM WITHIN A PATIENT, filed on Sep. 24, 2019, and which further claims priority to U.S. Provisional Patent Application No. 62/926,517, titled MATERIAL REMOVAL FROM WITHIN A PATIENT, filed on Oct. 27, 2019; the entire contents of each of the foregoing applications are hereby incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     Certain embodiments described herein relate generally to devices for removing unwanted materials from within patients, and further embodiments relate more particularly to devices, systems, and methods for removing material to treat pancreatitis. 
     BACKGROUND 
     Unwanted material within the body, such as may be found in blockages, can take various forms. For example, esophageal food impactions are a common and dangerous emergency in gastroenterology, with an annual incidence rate of at least 13/100,000 population (Longstreth, GIE; 2001); moreover, the incidence has been increasing in recent years due to a rise in eosinophilic esophagitis (Desai, GIE;  2005 ). Food impactions can occur when a bolus of swallowed food becomes lodged in the esophagus and is unable to pass spontaneously into the stomach. This occurs either when the swallowed bolus is too large or when there are diseases of the esophagus that narrow the esophageal lumen, such as GE reflux with a stricture or ring, an esophageal food allergy such as eosinophilic esophagitis with stricture or stenosis of the esophagus, a Schatzki&#39;s ring, esophageal webs, or esophageal cancer. Motility disorders of the esophagus typically do not cause impactions. 
     Food impactions present acutely and dramatically, with patients noting chest pain or pressure, inability to swallow, painful swallowing, a sensation of choking, and neck or throat pain. Retching and vomiting are also common, and patients can also experience breathing problems due to tracheal or airway compression, with stridor, coughing or wheezing being noted. Known devices, systems, and methods for treating food impactions suffer from one or more drawbacks that can be resolved, remedied, ameliorated, or avoided by certain embodiments described herein. 
     A variety of other conditions can give rise to and/or result from problematic undesirable material, which material may cause occlusions or blockages, within a patient. For example, in some instances, gallstones or tumors can become lodged in the biliary tree (i.e., in the common bile duct and/or in peripheral ducts). A variety of known methods are used to remove the gallstones or tumors from the bile ducts. 
     Moreover, gallstones or tumors lodged in bile ducts can cause chronic and/or acute pancreatitis, which can be treated by removal of unwanted material that collects within the pancreas. The term “pancreatitis,” as used herein, can include one or both of acute pancreatitis and chronic pancreatitis. Pancreatitis can result from other conditions as well, although gallstones are the most frequent cause in at least the western population. Pancreatitis is a serious disease resulting in significant morbidity and mortality. The two types of acute pancreatitis are interstitial edematous pancreatitis and necrotizing pancreatitis. With respect to necrotizing pancreatitis, necrosis develops as collections (e.g., fluid collections) in one or more of the pancreatic parenchyma or peripancreatic tissue. The collections are caused by inflammation and include acute peripancreatic fluid collections, pancreatic pseudocysts, acute necrotic collections, and walled-off necrotic collections. Collections usually remain sterile. While most resolve on their own, some can become pseudocysts, and a smaller portion can turn into walled-off necroses. Pseudocysts are collections in peripancreatic tissue that mostly contain solid material. In some instances, the pseudocysts can be blockages that occlude or partially occlude the main pancreatic duct or branches thereof. Walled-off necroses consist of mature necrotic material (both fluid and solid) completely encapsulated and demarcated inside a thickened wall of tissue lacking an epithelial lining. These usually develop about four weeks after onset of necrotizing pancreatitis. 
     Sterile necrotic collections often do not require any invasive intervention and resolve over time. In some instances, however, sterile necrotizing pancreatitis can occlude the gastric, intestinal, or biliary outlets due to size, and can benefit from intervention. Infection of pancreatic necrotic material is associated with significantly higher mortality than sterile necrosis and usually requires invasive or minimally invasive intervention. Infection of sterile necrotic tissue may, for example, be caused by movement of bacteria from the gastrointestinal tract to nearby necrotic pancreatic tissue. 
     Accordingly, undesirable materials (e.g., material that causes and/or results from one or more blockages within a patient), may desirably be removed from the patient. Such material can include, for example, food impactions within the esophagus. In further examples, the material can include gallstones and/or tumors that at least partially occlude bile ducts and/or debris (e.g., blockages) associated with pancreatitis, as well as other materials associated with pancreatitis, including fluid collections, pseudocysts, and/or walled-off necrotic collections. Other examples of materials can include gastric obstructions, such as stool impactions, blood (e.g., pooled blood and/or blood clots) within the gastrointestinal tract, bezoars in the gastrointestinal tract, and/or blood and/or mucous in the pulmonary tree. Known devices, systems, and methods for removing such undesired materials from within a patient suffer from one or more drawbacks that can be resolved, remedied, ameliorated, or avoided by certain embodiments described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The written disclosure herein describes illustrative embodiments that are non-limiting and non-exhaustive. Reference is made to certain of such illustrative embodiments that are depicted in the figures, in which: 
         FIG. 1  depicts a side elevation view of an illustrative embodiment of a catheter for clearing a blockage from within a body of a patient; 
         FIG. 2  depicts a side elevation view of an illustrative embodiment of a system for clearing a bolus of food or other debris or foreign body lodged within an esophagus of a patient, the system including the catheter of  FIG. 1 ; 
         FIG. 2A  is an end-on plan view of a distal tip of an embodiment of an endoscope that is compatible with the system of  FIG. 2 ; 
         FIG. 3  depicts a portion of the system of  FIG. 2  with the bolus of food or other debris being partially cored; 
         FIG. 4  depicts an illustrative embodiment of a distal end of the catheter for coring the bolus of food or other debris shown in  FIG. 1 ; 
         FIG. 5  depicts another illustrative embodiment of a distal end of a catheter for coring the bolus of food or other debris, such as that shown in  FIG. 1 ; 
         FIG. 6  depicts an illustrative embodiment of a proximal end of a catheter tube of  FIG. 1  coupled to an embodiment of a syringe; 
         FIG. 7  depicts a side elevation view of an illustrative embodiment of a stylet that is compatible with the system of  FIG. 2 ; 
         FIG. 8  depicts a side elevation view of the stylet of  FIG. 7  positioned within the catheter of  FIG. 1 ; 
         FIG. 9  depicts a schematic side elevation view of another embodiment of a catheter having a Y-fitting for removing a bolus of food or other debris lodged within an esophagus; 
         FIG. 10  is a perspective view of the catheter of  FIG. 9 ; 
         FIG. 11  is a perspective view of a proximal portion of the catheter of  FIG. 9  with a stylet advanced fully therethrough; 
         FIG. 12  shows another perspective view of the proximal portion of the catheter of  FIG. 9 ; 
         FIG. 13  shows another view of the proximal portion of the catheter of  FIG. 9  with the stylet partially removed therefrom; 
         FIG. 14  shows an enlarged view of the proximal portion of the catheter of  FIG. 9 ; 
         FIG. 15  shows another view of the proximal portion of the catheter of  FIG. 9  with a cap of the suction port removed; 
         FIG. 16  shows a distal end of the catheter of  FIG. 9 ; 
         FIG. 17  shows the distal end of the catheter of  FIG. 9 ; 
         FIG. 18  shows another example embodiment of a stylet for removing a bolus of food or other debris lodged within an esophagus; 
         FIG. 19  shows an end portion of the stylet of  FIG. 18 ; 
         FIG. 20  shows another example embodiment of a system for removing a bolus of food or other debris lodged within an esophagus; 
         FIG. 21  shows a portion of the device of  FIG. 20 ; 
         FIG. 22  shows another example embodiment of a system for removing a bolus of food or other debris lodged within an esophagus; 
         FIG. 23  shows a cross-sectional view of a portion of the device of  FIG. 22 ; 
         FIG. 24  shows another cross-sectional view of a portion of the device of  FIG. 22 ; 
         FIG. 25  is an exploded elevation view of another embodiment of a blockage clearing system; 
         FIG. 26  is a side elevation view of a proximal end of an embodiment of a sheath assembly that may be used with the system of  FIG. 25 ; 
         FIG. 27  is a cross-sectional view of a sheath portion of the sheath assembly of  FIG. 26  taken along the view line  27 - 27  in  FIG. 26 ; 
         FIG. 28A  is an elevation view of a distal end of the sheath assembly that includes a positioning element in an undeployed state; 
         FIG. 28B  is an elevation view of the distal end of the sheath assembly that depicts the positioning element in a deployed state; 
         FIG. 29  is an elevation view of a proximal end of an embodiment of a catheter assembly that may be used with the system of  FIG. 25 ; 
         FIG. 30  is a cross-sectional view of a catheter portion of the catheter assembly of  FIG. 29  taken along the view line  30 - 30  in  FIG. 29 ; 
         FIG. 31  is an elevation view of a distal end of the catheter of  FIG. 29 ; 
         FIG. 32A  is an early stage in an illustrative method of using the system of  FIG. 25  in which the sheath is inserted into the esophagus of a patient; 
         FIG. 32B  is a subsequent stage in the illustrative method in which the distal end of the sheath contacts an impacted bolus of food; 
         FIG. 32C  is a subsequent stage in the illustrative method in which the positioning element is deployed into contact with the esophagus; 
         FIG. 32D  is a subsequent stage in the illustrative method in which the distal tip of the catheter is advanced through the sheath and brought into contact with a proximal end of the food bolus; 
         FIG. 32E  is a subsequent stage in the illustrative method in which a morsel of food from the food bolus is cut or, more specifically, cored by the distal tip of the catheter and is drawn into a lumen of the catheter; 
         FIG. 32F  is a subsequent stage in the illustrative method in which the morsel of food has detached from the food bolus and is suctioned through the lumen of the catheter; 
         FIG. 32G  is a subsequent stage in the illustrative method in which the catheter is withdrawn into or from the sheath; 
         FIG. 32H  is a subsequent stage in a further illustrative method in which further coring of the food bolus is desired, wherein in the depicted stage, the positioning element is returned to the undeployed configuration to permit ready movement of the sheath relative to the esophageal wall; 
         FIG. 32I  is a subsequent stage in the further illustrative method in which the distal end of the sheath has been advanced to a more distal position, wherein the proximal end of the cored food bolus has been reshaped in the absence of the suctioned-off food morsel; 
         FIG. 32J  is a subsequent stage in the further illustrative method in which the positioning element is deployed again into contact with the esophagus; 
         FIG. 32  K is a subsequent stage in the further illustrative method in which the distal tip of the catheter is again brought into contact with the proximal end of the food bolus for further coring of the food bolus; 
         FIG. 33A  is an elevation view of a distal end of another embodiment of a sheath assembly that includes a differently shaped positioning element in an undeployed state; 
         FIG. 33B  is another elevation view of the distal end of the sheath assembly of  FIG. 33A  that depicts the positioning element in a deployed state in which the positioning element is substantially shaped as a frustocone; 
         FIG. 34  is an elevation view of a proximal end of another embodiment of a sheath assembly that includes a pressure regulation valve; 
         FIG. 35A  is an elevation view of a distal end of the sheath assembly of  FIG. 34  that depicts a positioning element in an undeployed state; 
         FIG. 35B  is a further elevation view of the distal end of the sheath assembly of  FIG. 34  that depicts the positioning element in a deployed state; 
         FIG. 35C  is a further elevation view of the distal end of the sheath assembly of  FIG. 34  that depicts the positioning element in a further state of operation in which the positioning element has been maintained in the deployed state at a substantially constant pressure via the pressure regulation valve of  FIG. 34 , despite attempts to further pressurize the positioning element; 
         FIG. 36  is an elevation view of a proximal end of another embodiment of a catheter assembly that, in some instances, may be used with a system such as that depicted in  FIG. 25 , or in other instances, may be used without a sheath; 
         FIG. 37  is a cross-sectional view of a catheter portion of the catheter assembly of  FIG. 36  taken along the view line  37 - 37  in  FIG. 36 ; 
         FIG. 38A  is an elevation view of a distal end of the catheter assembly of  FIG. 36  in which a positioning element is depicted in an undeployed state; 
         FIG. 38B  is another elevation view of the distal end of the catheter assembly in which the positioning element is depicted in a deployed state; 
         FIG. 39A  is an elevation view of a distal end of another embodiment of a catheter assembly that includes a differently shaped positioning element that is depicted in an undeployed state; 
         FIG. 39B  is another elevation view of the distal end of the catheter assembly of  FIG. 39A  that depicts the positioning element in a deployed state; 
         FIG. 40A  is an elevation view of a distal end of another embodiment of a catheter assembly that includes a differently shaped and differently oriented positioning element that is depicted in an undeployed state; 
         FIG. 40B  is another elevation view of the distal end of the catheter assembly of  FIG. 40A  that depicts the positioning element in a deployed state; 
         FIG. 41  is an elevation view of a distal end of another embodiment of a catheter assembly that depicts a distal tip of a catheter that includes an internal bevel; 
         FIG. 42  is an elevation view of a distal end of another embodiment of a catheter assembly that depicts a distal tip of a catheter that is substantially flat and that includes a cutting element recessed from the distal tip within a lumen of the catheter; 
         FIG. 43  is a cross-sectional view of the catheter assembly of  FIG. 42  taken along the view line  43 - 43  in  FIG. 42 ; 
         FIG. 44  is an elevation view of a distal end of another embodiment of a catheter assembly that depicts a distal tip of a catheter that is substantially rounded and that includes a cutting element recessed from the distal tip within a lumen of the catheter; 
         FIG. 45  is an elevation view of another embodiment of a blockage clearing system in an assembled, pre-use, undeployed, packaged, or insertion state; 
         FIG. 46  is an elevation view of an embodiment of a sheath assembly of the blockage clearing system of  FIG. 45 , the sheath assembly being shown in a deployed state; 
         FIG. 47  is a cross-sectional view of a hub of the sheath assembly of  FIG. 46 ; 
         FIG. 48  is a partial cross-sectional view of a portion of the sheath assembly that includes the hub, when the assembly is in an assembled state; 
         FIG. 49  is a cross-sectional view of a sheath of the sheath assembly of  FIG. 46  taken along the view line  49 - 49  in  FIG. 46  (not necessarily to scale); 
         FIG. 50  is an enlarged elevation view of a distal end of the sheath assembly of  FIG. 46 , which includes a positioning element that is depicted in a deployed state; 
         FIG. 51  is an elevation view of an embodiment of a catheter assembly that is compatible with the blockage clearing system of  FIG. 45  and/or, in other or further embodiments, is compatible for use with an endoscope; 
         FIG. 52  is a cross-sectional view of a catheter of the catheter assembly of  FIG. 51  taken along the view line  52 - 52  in  FIG. 51  (not necessarily to scale); 
         FIG. 53  is an enlarged elevation view of a distal end of the catheter; 
         FIG. 54  is a perspective view of an embodiment of a spacer compatible with the system of  FIG. 45 ; 
         FIG. 55  is an elevation view of an embodiment of a kit that includes the system of  FIG. 45 ; 
         FIG. 56  is an elevation view of another embodiment of a kit that includes an embodiment of the catheter assembly of  FIG. 51 ; 
         FIG. 57A  is an elevation view of another embodiment of a sheath assembly, which can be used with embodiments of systems previously disclosed, the sheath assembly being shown in an undeployed state; 
         FIG. 57B  is another elevation view of the sheath assembly of  FIG. 57A  shown in a deployed state; 
         FIG. 58A  is an elevation view of another embodiment of a sheath assembly, which can be used with embodiments of systems previously disclosed, the sheath assembly being shown in an undeployed state; 
         FIG. 58B  is another elevation view of the sheath assembly of  FIG. 58A  shown in a deployed state; 
         FIG. 59A  is an elevation view of another embodiment of a sheath assembly, which can be used with embodiments of systems previously disclosed, the sheath assembly being shown in an undeployed state; 
         FIG. 59B  is another elevation view of the sheath assembly of  FIG. 59A  shown in a deployed state; 
         FIG. 60A  illustrates a stage of illustrative methods for removing material from a pancreas to treat pancreatitis, wherein a portion of the gastrointestinal tract is shown in cross-section and an embodiment of an endoscope is shown in elevation; 
         FIG. 60B  illustrates another stage of certain of the illustrative methods in which a coring catheter is being inserted through the endoscope to core and suction away necrotic material, wherein a proximal end of the endoscope and a proximal end of the coring catheter are shown; 
         FIG. 60C  illustrates another stage of certain of the illustrative methods in which a distal end of the coring catheter has been inserted past a distal end of the endoscope to core and suction away necrotic material; 
         FIG. 60D  illustrates another stage of certain of the illustrative methods in which the endoscope and the coring catheter are inserted through a stent; 
         FIG. 61A  illustrates a stage of further illustrative methods for removing material from a pancreas to treat pancreatitis, wherein a portion of the gastrointestinal tract is shown in cross-section and an embodiment of an endoscope is shown in elevation; 
         FIG. 61B  illustrates another stage of certain of the illustrative methods of  FIG. 61A  in which a coring catheter has been inserted through the endoscope to core and suction away necrotic material; 
         FIG. 61C  illustrates another stage of certain of the illustrative methods of  FIG. 61A  in which the endoscope and the coring catheter are inserted through a stent; 
         FIG. 62A  is a perspective view of an embodiment of a material-disrupting device that may be used to cut, dislodge, or otherwise disrupt undesired material, and may be used independently or in conjunction with independently or in conjunction with a coring catheter for removal of the material from a patient; 
         FIG. 62B  is an exploded perspective view of a manual driver portion of the material-disrupting device of  FIG. 62A ; 
         FIG. 63  is an elevation view of another embodiment of a material disrupting device; 
         FIG. 64  is an elevation view of another embodiment of a material disrupting device; 
         FIG. 65  is an elevation view of another embodiment of a material disrupting device; and 
         FIG. 66  is an elevation view of a distal end of an embodiment of a coring catheter. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to devices, systems, and methods for removing undesired materials from within a patient, such as by addressing a blockage within a lumen of a patient. While specific examples of such devices, systems, and methods are discussed with respect to esophageal food impactions, the disclosure is not limited to this specific application. For example, other foreign bodies positioned within the esophagus and/or blockages within other body lumens or other regions of the body may be cleared in manners such as disclosed herein. Certain embodiments described herein can be used to clear, remove, break up, or otherwise treat other blockages within the body, such as those in the lungs. Moreover, additional examples are provided, including examples for the removal of necrotic material to treat pancreatitis. 
     With respect to food impactions, most food impactions clear spontaneously, but a significant fraction (20%) will not and have traditionally required emergent endoscopic intervention to clear the blocked food. This can be dangerous, since typical emergency endoscopy with removal of food can result in serious complications including aspiration pneumonia, laceration of the esophagus with bleeding, or esophageal perforation, which can result in sepsis and death. The complication rate of endoscopic clearance of a food impaction is approximately 3-5% and the mortality rate is unknown but several deaths have been reported (Simic, Am J Forensic Med Path; 1988). 
     Various endoscopic tools may be used to clear impactions, but all have flaws and there is no prior technique that is demonstrably better than any other. Food can sometimes be pushed blindly through the esophagus and into the stomach using the tip of the endoscope, but this technique is performed without vision of the more distal esophagus, so the endoscopist cannot observe, via the endoscope, what the esophagus looks like distal to the obstruction or what abnormalities exist. This technique can work well in some patients (Vicari, GIE; 2001), but because the technique is blind, can often result in esophageal laceration or perforation. Indeed, there is a significant risk the distal tip of the endoscope and/or a sharp surface within the bolus will be deflected toward the esophagus wall during blind pushing of this sort, resulting in laceration or perforation. Many endoscopists avoid blind pushing for this reason. 
     Some endoscopic techniques employ forceps that include “rat-tooth” type designs, snares, or variable wire basket designs to break up food into smaller pieces for extraction. Such techniques are laborious, time-consuming, and often fail. 
     Other extraction techniques can also be tried, particularly when the food bolus is not tightly wedged and is firm, or if the food contains bone or sharp surfaces. In this regard, baskets, snares, graspers, “pelican” forceps with longer arms, nets, etc., can be used to remove food in whole or in pieces, but these techniques also frequently fail, and the patient is at risk for aspiration pneumonia if the pieces fall into the hypopharynx or mouth during the extraction attempts. If the food bolus is lodged proximally, then most of the above techniques will fail or are too dangerous to try. Endoscopic suction cannot be used for impactions, since a food bolus cannot be effectively suctioned through an endoscope. Moreover, if suction is used in an attempt to hold the food bolus against a distal tip of the endoscope, and the suction fails at some point to hold a bolus against the tip of the scope, the patient is at high risk for aspiration as the scope is withdrawn through the hypopharynx or mouth. Overtubes for endoscopes can be used if repeated endoscopic intubation is needed, but overtubes are uncomfortable, require deeper sedation, and can be dangerous in and of themselves with risk of esophageal laceration and perforation. 
     Certain embodiments disclosed herein can resolve, remedy, ameliorate, and/or avoid one or more of the limitations of known techniques for treating a patient who suffers from an esophageal food impaction, such as those just described, and/or can be advantageous over such techniques for other reasons, as will be apparent from the present disclosure. 
     In certain embodiments, a device is configured to clear a bolus of food impacted within an esophagus. The device can include a catheter tube having a hollow interior and a distal end configured to core the bolus of food and can include a proximal end configured to be coupled to a source of suction to clear the core. Certain systems described herein assist in resolving the buildup of pieces of food in the esophagus while minimizing the risk of aspiration. The systems are further designed in an atraumatic manner, helping to avoid esophageal laceration and perforation. In some embodiments, an inner region of a food impaction that is spaced from the esophageal wall (e.g., the mid-region or center of the food impaction) is cored out. 
     For example, in one embodiment, the system includes a catheter (e.g., hollow tube) with a distal end that is delivered to the site of the blockage. The distal end of the catheter is used to core out portions of the blockage until the blockage is reduced in volume in a piecemeal manner. The smaller volume blockage can then pass through the esophagus spontaneously and/or be more easily removed. In some embodiments, the catheter can be delivered to the blockage site through an endoscope (e.g., through the instrument channel of the endoscope) or other similar device. 
     In other or further embodiments, the catheter can be delivered to the blockage site through a dedicated or specialized sheath, which may include a positioning element to prevent the catheter tip from contacting the esophageal wall. In some instances, the dedicated sheath may permit the catheter to define a larger internal lumen, as compared with catheters that are deployed through the instrument or working channel of a standard endoscope, which can facilitate and/or increase a rate of blockage clearance. The dedicated sheath may permit the catheter to be used in a blind procedure, such as in an emergency room setting, without endoscopic or other visualization of the impaction during the procedure. In some embodiments, the sheath includes a positioning element that spaces the distal tip of the catheter away from the esophageal wall to prevent laceration or perforation of the esophagus. 
     In still other or further embodiments, the catheter itself may include a positioning element to prevent the catheter tip from contacting the esophageal wall. In some instances, the catheter may be used without an endoscope or other sheathing element. 
     In certain examples, suction can be provided to remove the cored portions of the blockage. The suction can be provided at the proximal end of the catheter to assist with the coring and/or to cause the cored portions to be suctioned from the site of the blockage and passed through the catheter and discarded, thus minimizing a risk of food aspiration. In some instances, suctioning arrangements can preserve endoscopic visualization. Stated otherwise, a coring aspiration catheter may be deployed through the working channel of an endoscope to remove portions of a food bolus without blocking a viewing lens at a distal end of the endoscope and/or without obscuring, or without significantly or fully obscuring, a field of view of the lens. For example, the impacted food bolus and the coring aspiration catheter may be viewed via the viewing lens at the distal end of the endoscope throughout at least a portion of the clearing procedure. 
     Certain embodiments can include features that allow cored portions of the food to be cleared, should the portions become caught in the catheter while being suctioned away from the blockage site. In one example, a source of compressed air, such as a syringe, can be placed at the proximal end of the catheter, and air can be passed through the catheter to clear any portions caught in the catheter, via the distal end. In other or further embodiments, a stylet can be passed through the interior of the catheter to clear any portions of food caught therein. The stylet can also perform other or further functions, such as providing stiffness for the catheter during delivery of the catheter to the blockage site. Further, the stylet can be configured to assist in the manipulation of the blockage, such as by advancing the stylet into the blockage one or multiple times to create a nidus for coring and suctioning. 
     One or more of the foregoing advantages and/or one or more other or further advantages will be apparent from the discussion that follows. 
     Referring now to  FIG. 1 , an example catheter  100 , which may also be referred to as a catheter assembly  100 , is shown. The catheter  100  includes a hollow catheter tube  102  that generally can be used to core out a portion of a blockage. Specifically, the catheter tube  102  includes a distal end  104  that is configured to contact and core the blockage one or more times. As the blockage is cored by the distal end  104  of the catheter tube  102 , the volume of the blockage is reduced until the blockage is able to be passed through the esophagus spontaneously and/or removed. 
     The catheter assembly  100  includes a proximal end  106  configured to be coupled to various devices. For example, as described further below, the proximal end  106  of the catheter assembly  100  is configured to be coupled to a source of suction to allow the cored food portions to be suctioned and/or removed through the catheter tube  102 . In another example, the proximal end  106  of the catheter tube  102  is configured to be coupled to a source of pressurized air, such as a syringe, to allow any cored food stuck within the catheter tube  102  to be cleared. Other configurations are possible. In the illustrated embodiment, the proximal end  106  is formed as a tapered connector that can be directly connected to a standard vacuum tubing arrangement, such as in a hospital setting, as discussed further below with respect to  FIG. 2 . 
     The catheter or catheter assembly  100  can include a strain relief sleeve  53  of any suitable variety. The strain relief sleeve  53  can inhibit kinking or other undesirable deformation of the catheter tube  102  during use of the catheter tube  102 . In some embodiments, the catheter  100  includes a shoulder  55  at a proximal end of the strain relief sleeve  53 . The shoulder can define a larger diameter than the strain relief sleeve  53 . The catheter  100  can further include a handle  57  via which a user may manipulate the proximal end of the catheter  100 . 
     Referring now to  FIGS. 2 and 3 , the catheter  100  is shown within an example system  200  configured to remove a blockage  202  positioned within an esophagus  204  of a patient. In this example, the blockage  202  (generally food or other debris, but could also be other blockages like blood or blood clots, mucus, etc.) has become caught within the esophagus  204 . 
     In the embodiment shown, the catheter  100  is delivered to the blockage  202  using an endoscope  210 . The endoscope  210  can be of any suitable variety, including those presently in use and/or those yet to be devised. For example, the endoscope can be any of a variety of standard endoscopes typically used for upper GI tract endoscopy. As shown in  FIG. 2A , the endoscope  210  contains a working channel  260  that is generally hollow and allows the catheter  100  to be delivered through the endoscope  210  to the blockage  202 . The endoscope  210  may generally be referred to as a tubular member that defines a channel—specifically, the working channel  260 . 
     In various embodiments, the endoscope  210  can include one or more additional ports having a variety of additional functions. For example, in the illustrated embodiment, the endoscope  210  includes a viewing port  262 , which may include a lens, via which a region beyond the distal tip of the endoscope  210  can be viewed. The endoscope  210  can further include a light guide that terminates at a light port  264  for illuminating the region beyond the distal tip of the endoscope  210 . The endoscope  210  can include a water jet  266  and/or can include an air and/or water nozzle  268 . Various embodiments of endoscopes can include more or fewer features. 
     With continued reference to  FIGS. 2 and 3 , once the distal end  104  of the catheter tube  102  is in position, the endoscope  210  can be withdrawn or can remain in place as the blockage  202  is manipulated. In many methods, the endoscope  210  remains in close proximity to the blockage  202  during coring via the catheter tube  102  to permit visualization of the coring. In particular, the endoscope  210  can be positioned such that the region that is illuminated by the light port  264  and that is within the field of view of the lens of the viewing port  262  includes both the proximal end of the blockage  202  and the distal end of the catheter tube  102  as the catheter tube  102  is used to core pieces out of the blockage  202 . 
     The catheter tube  102  of the catheter  100  is configured to be advanced so that the distal end  104  impacts the blockage  202  so as to reduce the volume of the blockage  202 , such as by repetitively coring the food. As the volume is reduced (such as is shown in  FIG. 3 ), the blockage  202  can be naturally passed through the esophagus  204  and into a stomach  206  of the person. 
     In example embodiments, the catheter tube  102  is at least semi-rigid but flexible, which allows the catheter tube to flex and/or bend during delivery through the endoscope, as the endoscope flexes and bends. This allows the catheter tube  102  to be directed more precisely as it is inserted to a desired location. For example, in some instances, the endoscope is introduced into the patient through the nose of the patient—or stated otherwise, is introduced into the patient via transnasal endoscopy—such that the endoscope defines a curved route through the upper respiratory tract of the patient. In other instances, the endoscope is introduced into the patient through the mouth, such that the endoscope defines a curved route from the mouth to the esophagus, in manners such as described elsewhere herein. The catheter tube  102  may be sufficiently flexible to pass through the curved portion of the endoscope, or more specifically, pass through the curved portion of the working channel  260 . 
     In some examples, the distal end  104  of the catheter tube  102  is configured to assist in the coring of the blockage  202 . For example, as shown in  FIG. 4 , the distal end  104  of the catheter tube  102  is tapered. Specifically, the distal end  104  includes an inner diameter  402  that is smaller than an inner diameter  404  of a more proximal portion  406  of the catheter tube  102 . In one example, the difference in diameters can be less than one-hundredth of a millimeter. Other sizes are possible. In addition, the walls of the catheter tube  102  can be thinned as the walls extend to the distal end  104 , as depicted. 
     This tapering of the distal end  104  can allow a core  410  of the blockage  202  that is formed by the distal end  104  to be more easily suctioned through the catheter tube  102 . Since the cores formed by the distal end  104  will typically have a diameter smaller than that of the portion  406 , the cores can be more easily suctioned through the catheter tube  102  for evacuation, as is illustrated by Poiseuille&#39;s law. 
     In another depiction shown in  FIG. 5 , the catheter tube  102  is formed of a first portion  502  at the distal end  104  having a smaller diameter, and a second portion  504  extending along a remainder of the catheter tube  102  having a larger diameter. This again allows the cores of the blockage  202  that are created by the first portion  502  to be smaller in diameter so that the cores can more easily pass through the remainder of the catheter tube  102  (i.e., the second portion  504 ). 
     In some examples, a tip  508  of the distal end  104  of the catheter tube  102  can be beveled and/or serrated. The tip  508  can take multiple forms, including a serrated edge, to cut (e.g., saw) or shave bits of the blockage  202  off of the bolus to better aid suctioning. The tip  508  can help core the blockage. For example, in some instances, the catheter tube  102  may be rotated relative to the working channel of the endoscope, whether in a single direction or back and forth, as the tip  508  contact the blockage  202 . In some instances, this rotation, coupled with a serrated or otherwise configured tip can assist in coring the blockage  202 . This technique may be used with other embodiments as well, including those in which a catheter is inserted through a sheath assembly, rather than an endoscope. 
     For example, referring again to the system  200  depicted in  FIG. 2 , a source of suction can be applied to the proximal end  106  of the catheter  100  to allow the cores of the blockage  202  to be removed through the catheter tube  102 . Specifically, in the example provided, a vacuum line  220  can be coupled to the proximal end  106  of the catheter tube  102 . In particular, the vacuum line  220  can include a suction line fitting  221  that is connected to the proximal end  106  of the catheter  100 . The vacuum line  220  can be coupled to a collection canister  222  of any suitable variety, including those presently known or those yet to be devised, and the collection canister  222  is coupled to a suction line  224 . The suction line  224  is coupled to a source of suction, such as a hospital vacuum source. In this configuration, pieces of the blockage  202  that are cored or otherwise dislodged by the catheter tube  102  can thereupon be sucked up the catheter tube  102 , through the vacuum line  220 , and collected in the collection canister  222 . 
     As described previously, it is possible for one or more cores of the blockage  202  to become stuck within the catheter tube  102 . In such a scenario, various devices can be used to clear the stuck cores. 
     For example, referring now to  FIG. 6 , an example syringe  602  is coupled to the proximal end  106  of the catheter  100  using, for example, a suction line fitting or Luer-lock style connection. In this embodiment, the syringe  602  can be a typical  60  cc syringe that is used to deliver air into the catheter tube  102  during coring of the blockage  202  to dislodge and/or remove portions of the blockage  202  that are in the catheter tube  102 . 
     In this instance, a plunger of the syringe  602  is actuated to displace air within the syringe  602  into and through the catheter tube  102 . This air can be used to dislodge obstructions within the tube. Other configurations are possible. For example, other types of fluids, such as a jet spray of water, could be used to help clear the tube or break up food. 
     In other instances, different devices can be used to clear the catheter  100 . For example, referring now to  FIG. 7-8 , a stylet  700  is shown that is sized to fit through the hollow interior of the catheter tube  102 . Generally, the stylet  700  can be used to perform various functions. 
     For example, the stylet  700  can be used to stiffen the catheter  100  during delivery to the blockage  202 . Further, the stylet  700  can be introduced through the catheter tube  102  to clear the catheter tube  102  when one or more cores get stuck, performing a function of a pusher rod. In other or further instances, the stylet  700  can be used to pierce the blockage  202  to start a nidus for coring and suctioning. In various examples, the stylet  700  can be solid or hollow. 
     In the illustrated example, the stylet  700  further includes a stylet knob  702  that is configured to be engaged with the proximal end  106  of the catheter  100 . The proximal end  106  can be configured to include a Luer taper that allows the proximal end  106  to engage the stylet knob  702  of the stylet  700 . Other coupling arrangements, such as a threaded engagement, for example, can be used. 
     As shown in  FIG. 8 , the stylet knob  702  is coupled to the proximal end  106  of the catheter tube  102 . In this configuration, the catheter  100  can be delivered to the desired location within the esophagus  204 . At that time, the stylet knob  702  can be disengaged from the proximal end  106  to free the stylet  700  for movement. This movement can include the caregiver pushing the stylet  700  into and out of the catheter tube  102  to generally disrupt the blockage  202  and/or removal of the stylet  700  completely from the catheter tube  102 . 
     When the stylet  700  is removed from the catheter tube  102 , the vacuum line  220  can be connected to the proximal end  106  of the catheter tube  102  for suctioning, as described previously. 
     In this example shown in  FIG. 8 , the catheter tube  102  is approximately 80.5 inches in length and the stylet  700  is approximately 84 inches in length, although many different lengths can be provided such as, for example, shorter lengths for children and longer lengths for adults or to accommodate different length endoscopes, bronchoscopes or colonoscopes. The example catheter tube  102  has an outer diameter of 0.135 inches and an inner diameter of 0.115 inches. The stylet  700  has an outer diameter of 0.105 inches. Other sizes can be used. 
     In other embodiments, the catheter tube  102  can be variable in length and diameter, or stated otherwise, a variety of lengths and diameters are contemplated. For example, another embodiment of the catheter tube  102  measures 0.093 inches in outer diameter and 0.082 for the inner diameter, allowing for easy introduction and sliding within the working channel of any of a variety of endoscopes. The catheter tube  102  is long enough to extend through an endoscope. In some embodiments, the catheter tube  102  is at least 120 cm in length, but it can be longer in other embodiments. 
     The stylet  700  can vary in diameter, but in the preferred embodiment measures 0.070 inches in outer diameter to allow easy introduction and sliding within the catheter tube  102 , and is slightly longer than the catheter tube  102  to allow the stylet  700  to extend beyond the distal end  104  of the catheter tube  102  to clear the catheter tube  102  and extend further into the blockage  202 , if desired. 
     The catheter tube  102  can be made from a thin-walled extruded tube sized to fit the working channel (e.g., biopsy channel) of any commercially available endoscope. One example material is PEBAX® 7233 SA, available from Arkema, or any other suitable thermoplastic elastomer. Another possible material is an extrusion grade of PETG (glycol-modified polyethylene terephthalate). Other suitable materials include polyamide or extrusion grade Nylon or DEL R  IN® (acetal homopolymer resin, an engineering thermoplastic, available from DuPont), such as Nylon 10 or Nylon 12. 
     The stylet  700  could be made of the same or similar material. For example, the catheter tube  102  and the stylet  700  can be made of the same material to allow the stylet  700  to fit within the catheter tube  102  while minimizing friction. However, other materials and different materials for each can be used. 
     The above materials would clear food, but would not seriously damage the walls of the esophagus should they inadvertently contact the walls of the esophagus. 
     Referring now to  FIGS. 9-17 , another example device  900  is shown. The device  900  includes the catheter tube  102  with a suction port  902  at the proximal end  106  and with the distal end  104  that is designed (e.g., beveled) to be advanced through the biopsy channel of any commercial endoscope and that can accommodate the stylet  700  to clear any food that may stick in the catheter tube  102  after removal from the esophagus. 
     As shown in  FIG. 9 , the catheter tube  102  is designed to fit through the biopsy channel of an endoscope positioned within the esophagus to reach a food blockage, but can also be advanced adjacent to an endoscope and can also be advanced orally without the aid of an endoscope. The catheter tube  102  is also bendable and maneuverable as the endoscope bends and maneuvers, yet is rigid enough to withstand kinking. The catheter tube  102  is also sufficiently rigid to withstand suction forces that are sufficient to remove cored portions of a food or other blockage through the lumen of the catheter tube  102 . 
     In this example (see  FIGS. 9 and 15 ), there is a Y-fitting  904  wherein one arm  906  of the Y is attached to and forms the suction port  902 , and another arm  908  of the Y accommodates the stylet  700 . 
     There is also a compression seal  910 , or rubber stopper, at the proximal end of the arm  908  that accommodates the stylet  700 , so that any air escaping the proximal end—or entering through the proximal end—is minimized when the stylet  700  is in the catheter tube  102 , so that suction and stylet clearance of the vacuum tube can occur simultaneously. When the compression seal  910  is loosened, the stylet  700  can be easily advanced into and out of the catheter tube  102  using a handle  912  of the stylet  700 . The compression seal  910  can also secure the stylet  700  in any location along the shaft of the catheter tube  102 . 
     In this example, a cap  914  is threaded onto the proximal end  916  of the arm  908  to retain the compression seal  910  in place. Upon removal of the stylet  700  from the catheter tube  102 , the compression seal  910  is configured, in some embodiments, to close the proximal end  916  so that suction can be performed through the catheter tube  102  and the suction port  902 . 
     In the example shown, the catheter tube  102  can work with the stylet  700  completely removed; the stylet  700  can also be introduced as needed, and advanced any distance in the catheter tube  102 . 
     As with previous embodiments, the distal end  104  of the catheter tube  102  can disrupt food, core food, shave food and suction food. The catheter tube  102  wall could be thin and rigid to better accommodate a larger lumen of the tube. The stylet  700  can help support the catheter tube  102  to help prevent kinking, in some embodiments. Thus, in some instances, the stylet  700  can both help clear the suction tube and act as a stylet to stiffen the catheter tube  102 . 
     Many alternative designs are possible. For example, in another design shown in  FIGS. 18-19 , a stylet  1800  could have a spline shape  1802  with splines  1804  formed along the stylet to better accommodate suction when the stylet in is the catheter tube. In other words, spaces  1806  are formed between the splines  1804  to allow suction to be provided through the catheter tube  102  even with the stylet  1800  in place within the catheter tube  102 . Other configurations are possible. 
     Referring now to  FIGS. 20-21 , another example of a stylet  2000  is shown. In this example, the stylet  2000  is a wire  2002  with a piston  2004  positioned at an end  2006  thereof. The piston  2004  can be automatically (and/or manually) actuated intermittently or at regularly intervals (such as by a motor) to drive the stylet  2000  through the catheter tube  102  to engage the blockage in the esophagus. Other configurations are possible. 
     Referring now to  FIGS. 22-24 , another example device  2200  is shown. The device  2200  is similar to the embodiment of  FIGS. 20-21 , except that the device  2200  does not necessarily need suction. Instead, the device  2200  includes a handle  2202  and a tube  2204 . The handle  2202  includes an actuator member  2206  that can be moved (e.g., by the caregiver&#39;s finger or thumb) in a direction  2208  in or out. 
     The actuator member  2206  is coupled to a wire  2210  that runs through the tube  2204  to an ejector piston  2402 . The ejector piston  2402  is positioned within a cavity  2404  formed in a distal end  2406  of the tube  2204 . The distal end  2406  of the tube  2204  forms an opening  2408  sized to core or otherwise carve the obstruction as the caregiver moves the handle  2202  and the tube  2204  attached thereto. This is accomplished, for example, by the pieces of the obstruction being carved by the distal end  2406  of the tube  2204  and received in the cavity  2404 . 
     As the cavity  2404  is filled, the caregiver can move the actuator member  2206  to cause the ejector piston  2402  to be moved by the wire  2210  through the cavity  2404  towards the distal end  2406  of the tube  2204  to eject food out of the opening  2408 . This process can be done multiple times until the obstruction is cleared. The actuator member  2206  can be biased to return to the retracted position and/or simply be moved in the opposite direction  2208  by the caregiver&#39;s finger to return the ejector piston  2402  to the retracted position. 
     In some examples, the distal end  2406  of the tube  2204  can be configured to more easily core the obstruction. For example, the distal end can be thinned or serrated so as to be sharper. In other examples, additional features, such as a stainless steel tip, can be added to the distal end  2406  of this (or any other embodiment disclosed herein) to enhance the coring impact of the device  2200 . 
     In some examples, the inner surface of the tubes can be configured to more easily allow cores of the obstruction to pass therethrough. For example, the inner surface of a tube can be coated with a low friction or lubricious material to encourage passage and discourage clumping of the cores. Examples of such low friction materials include, without limitation, polyvinyl pyrrolidone and hyaluronic acid. Such materials can be typically bonded using heat or ultraviolet light. The external surface of the catheter  102  can optionally also be coated with low friction materials to enable passage through the endoscope. Other mechanisms, such as differing tapers and/or channeling of the inner surface, can also be used. 
     Further embodiments of blockage clearing systems are disclosed hereafter. The systems can resemble systems described above in certain respects. Specific features of these further systems may not be shown or identified by a reference numeral in the drawings or specifically discussed in the written description that follows. However, such features may clearly be the same, or substantially the same, as features depicted in other embodiments herein (whether discussed above or below) and/or described with respect to such embodiments. Accordingly, the relevant descriptions of such features apply equally to the features of the following systems. Any suitable combination of the features and variations of the same described with respect to any of the systems and their components can be employed with any of the remaining systems and their components, and vice versa. Moreover, with respect to certain embodiments described hereafter, similar components among various embodiments may be identified with similar numbering, wherein the initial numerals may be incremented in subsequently disclosed embodiments. 
       FIG. 25  depicts an exploded view of an embodiment of a blockage clearing system  3000  that includes a sheath assembly  3002  and a catheter assembly  3004 . The sheath assembly  3002  is configured to be coupled with the catheter assembly  3004  during use, as further discussed below. Moreover, the catheter assembly  3004  is configured to be coupled with a suction system  3006  during use. 
     The sheath assembly  3002  extends between a proximal end  3010  that is configured to remain outside of the patient during use and a distal end  3012  that is configured for insertion into the esophagus of a patient. The illustrated sheath assembly  3002  includes a hub  3014 , a sheath  3016 , and a positioning element  3018 . As further discussed below, the hub  3014  of the sheath assembly  3002  can be configured to direct a catheter  3026  of the catheter assembly  3004  into a lumen of the sheath  3016 . The catheter  3026  may also be referred to as a catheter tube, or more generally, as a tube, cannula, cutting member, cutting-and-suction member, or coring member. In further instances, the catheter  3026  may be referred to as an aspiration catheter, aspiration cannula, or aspiration tube. 
     At least a proximal portion of the sheath  3016  may define a preformed curve region  3017 . In some embodiments, the curved region  3017  is sized and oriented to facilitate introduction of the sheath  3016  into the esophagus of a patient. The curved region  3017  may additionally or alternatively enhance the patient&#39;s comfort during use of the sheath  3016 , such as when the curved portion  3017  extends through the mouth, against or adjacent to the soft palate, and through the hypopharynx. The curved portion  3017  may be pre-formed to correspond to a natural curvature of a patient&#39;s anatomy. In some embodiments, different sized sheath assemblies  3002  may be used for different sized patients to adjust to their differently sized anatomies, which may enhance comfort of the patients. In other embodiments, the curved region  3017  may be sufficiently flexible to adjust to different patient anatomies. A variety of configurations and alterations are contemplated. For example, in other embodiments, the sheath  3016  may be devoid of a curved region  3017 . As can be appreciated from the foregoing, in such embodiments that lack a pre-formed curved region  3016 , the sheath  3016  may be substantially linear prior to insertion into the patient, and can be sufficiently flexible to follow, deflect, adjust, and/or conform to a curvature of the patient&#39;s anatomy as the sheath  3016  is advanced through the mouth, against or adjacent to the soft palate, and through the hypopharynx of the patient. In other or further embodiments, the sheath  3016  may be advanced through the nose and through at least a portion of the upper respiratory tract and into the esophagus of the patient. 
     As further discussed below, the positioning element  3018  can assist in centering or otherwise positioning a distal tip  3023  of the catheter  3026  relative to the esophagus to prevent the distal tip  3023  from contacting or damaging the esophagus. In the illustrated embodiment, the positioning element  3018  is formed as an inflatable balloon  3019 . Other or further varieties of positioning elements  3018  are also contemplated, illustrative examples of which are discussed further below. In various embodiments, the positioning element  3018  may also or instead be referred to as a centering element, anchoring element, contact element, expansion element, spacing element, and/or as a centering, anchoring, contact, expansion, and/or spacing member. 
     With continued reference to  FIG. 25 , the catheter assembly  3004  extends between a proximal end  3020  that is configured to remain outside of the patient during use and a distal end  3022  that is configured for insertion into the esophagus of a patient. As further discussed below, the distal end  3022  of the catheter  3026  can include a distal tip  3023  that is capable of coring an impacted food bolus. The distal tip  3023  may be sharp, and may be referred to as one or more of a cutting tip or a coring tip. In some embodiments, the distal tip  3023  can cut into the food bolus on its own and/or in combination with suction provided by the suction system  3006 . In further embodiments, the distal tip  3023  can cooperate with the suction provided by the suction system  3006  to core the food bolus, e.g., as the suction tears from the food bolus a morsel that has been cut by the distal tip  3023 . 
     The illustrated catheter assembly  3004  includes a hub  3024  attached to a proximal end of the catheter  3026 . As further discussed below, the catheter hub  3024  can be configured to selectively couple with the suction system  3006 . In the illustrated embodiment, the catheter hub  3024  includes a connector  3028  for establishing a fluid connection to the suction system  3006 . In the illustrated embodiment, the connector  3028  is formed as a Christmas tree fitting or connector  3029 . Any other suitable connection interface is contemplated. For example, the connector  3028  may instead define a substantially smooth outer surface, such as a smooth conical surface similar to that of the connector at the proximal end  106  of the catheter assembly  100  depicted in  FIG. 1 , rather than a ribbed outer surface of multiple stacked conical surfaces, such as depicted in  FIGS. 25 and 29 . 
     In the illustrated embodiment, the catheter hub  3024  includes a handle  3040  and a suction port  3042  positioned thereon. The handle  3040  can be of any suitable configuration. In many embodiments, the handle  3040  is sized and shaped to rest or be gripped comfortably within a single hand of a practitioner. For example, in some embodiments, the handle  3040  can be gripped with four fingers of a hand of a practitioner, and the port  3042  can be operated with the thumb of the same hand of the practitioner. In some embodiments, the port  3042  can be left open to prevent suction from being applied, or to significantly reduce an amount of suction being applied, through the catheter  3026 . Conversely, the port  3042  can be closed, such as by placing a thumb or other finger thereon, to permit or increase an amount of suction to be applied through the catheter  3026 . In other embodiments, such as in the catheter assembly  100  discussed above, the handle  3040  can be devoid of a suction port  3042 . In such embodiments, suction through the catheter assembly  3004  can be continuous when the connector  3028  is coupled with the suction system  3006 . 
     In the illustrated embodiment, the suction system  3006  includes a suction tube  3044 , a container or suction trap  3046 , and a suction, aspiration, or vacuum source  3048 . The suction tube  3044  may be of any suitable variety, and may be configured to couple with the connector  3028  of the catheter assembly  3004 . For example, in some embodiments, the suction tube  3044  may include a suction fitting  3045 , such as the suction fitting  221  discussed above. The suction trap  3046  can be configured to permit air to pass through, but may be configured to retain therein pieces of a food bolus that are removed from a patient via the system  3000 . The suction trap  3046  may include any suitable filters or other arrangements, including those known in the art or those yet to be devised. For example, the suction trap  3046  can comprise a collection cannister, such as the collection cannister  222  disclosed above. The vacuum source  3048  may be of any suitable variety. For example, in some embodiments, the vacuum source  3048  can be a dedicated vacuum line or vacuum system of a hospital. 
     With reference to  FIG. 26 , the proximal end  3010  of the sheath assembly  3002  is shown in greater detail and from a viewpoint that is rotated 90 degrees about a vertical axis relative to the view of  FIG. 25 . In the illustrated embodiment, the sheath hub  3014  includes a housing element  3050  that defines an entry passage or guide  3052 . In the illustrated embodiment, the guide  3052  is substantially funnel shaped, which can facilitate insertion of the distal end  3022  of the catheter  3026  into a lumen  3054  of the sheath  3016 . 
     The sheath hub  3014  further includes an actuator  3060  via which the positioning element  3018  can be deployed. In particular, in the illustrated embodiment, the actuator  3060  is configured as an inflation port  3060  via which the balloon  3019  can be selectively inflated or deflated. Stated otherwise the actuator  3060  is communicatively coupled with the balloon  3019 , and, in this instances, the communication comprises fluid communication. The illustrated inflation port  3060  includes a connector  3062 , such as a Luer fitting  3063 , via which any suitable inflation device can be connected thereto. In various embodiments, the inflation device can be an air-, gas- liquid-, or other fluid-filled syringe or other medical fluid delivery device. In various embodiments, saline, air, nitrogen, or any other suitable fluid may be used to inflate the balloon  3019 . In some embodiments, the inflation device may have its own pressure controls, such as to ensure that the fluid is delivered to the balloon  3019  within an acceptable range, or stated otherwise, does not exceed a predetermined limit. Any suitable inflation device, including any known in the art or any yet to be devised, is contemplated. 
     The sheath hub  3014  can further include a stopcock  3064  that can be selectively opened and closed via a handle or lever  3065 . The stopcock  3064  can be opened to permit inflation or deployment of the balloon  3019 , and can be closed maintain the balloon  3019  in an inflated or deployed state. In particular, the stopcock  3064  can be in an open configuration to permit passage of inflation fluid therethrough for inflation of the balloon  3019 , and once the balloon  3019  has been filled to a desired amount and/or the fluid pressurized to a desired or predetermined level, the stopcock  3064  can be closed to prevent passage of the fluid back through the stopcock and thus maintain the balloon  3019  in a filled, inflated, and/or pressurized state. 
     The inflation port  3060  can be in fluid communication with an inflation lumen  3066 , which may also be referred to as an inflation passageway, channel, etc. Stated otherwise, and is apparent from at least the foregoing, the connector  3062  is in fluid communication with the stopcock  3064 , and the stopcock  3064  is in fluid communication with the inflation lumen  3066 . When the stopcock  3064  is in the open state, the connector  3062  is in fluid communication with the inflation lumen  3066 , and when the stopcock  3064  is in the closed state, the connector  3062  no longer fluidly communicates with the inflation lumen  3066 . The stopcock  3064  may be said to be in line with, between, or fluidly coupled with the connector  3062  and the inflation lumen  3066 . In the illustrated embodiment, the housing  3050  defines a proximal end of the inflation lumen  3066 , and the inflation lumen  3066  extends through a sidewall of the sheath  3016 . As shown in  FIG. 26 , an extender  3067  of any suitable variety may extend between the housing  3050  and the stopcock  3064  to establish fluid communication between the inflation port  3060  and the inflation lumen  3066 . For example, the extender  3067  can comprise tubing (e.g., flexible tubing) of any suitable variety. 
     The extender  3067  may alternatively be referred to as an extension line. Further, the extender  3067  and the inflation port or actuator  3060  may be referred to, collectively, as an actuation branch  3068  of the sheath assembly  3002 . 
     With reference to  FIG. 27 , the inflation lumen  3066  and the instrument delivery lumen  3054  of the sheath  3016  are shown in greater detail. Any suitable arrangement of the lumens  3054 ,  3066  is contemplated. In various embodiments, more than one inflation lumen  3066  may be present. For example, in some embodiments, one or more additional inflation lumens may be present in the sheath  3016  for redundancy in the event that one of the lumens is inadvertently blocked, such as due to kinking of the sheath  3016 . The sheath  3016  may generally be referred to as a tubular member that defines a channel through which the catheter  3026  can be advanced. In particular, the sheath  3016  defines the working channel or lumen  3054 . 
     In various embodiments, the sheath  3016  may be formed of a material and/or a thickness of the sidewall may be sufficient to provide the sheath  3016  with desirable amounts of columnar or other strength. For example, in various embodiments, the sheath  3016  can resist compression, crushing, kinking, and/or other deformation that could undesirably alter the shape of the lumen  3054  in a manner that could interfere with insertion therein and/or removal therefrom of the catheter  3026 . As previously noted, the material may also be flexible so as to permit the sheath  3016  to conform to the anatomy of a patient. For example, the material may be sufficiently flexible to permit the sheath  3016  to be bent from a substantially linear arrangement to a curved arrangement as the sheath  3016  is inserted through the mouth of the patient into the esophagus, all while maintaining the lumen  3054  sufficiently patent to permit ready passage therethrough of the catheter  3026 . Various suitable materials for a catheter are disclosed above, and in many instances, these and/or other suitable materials for the sheath are contemplated. For example, in various embodiments, the sheath  3016  comprises any suitable thermoplastic elastomer, such as any suitable variety of PEBAX®, available from Arkema. Moreover, in some embodiments, a lubricious layer or coating may be provided at the inner surface of the sheath  3016 , which could facilitate insertion of the catheter  3026  into the lumen  3054  and/or removal of the catheter  3026  from the lumen  3054 . 
     Any suitable size of the sheath  3016  for insertion into the esophagus is contemplated. For example, in various embodiments, the sheath  3016  (i.e., the outer diameter thereof) can be no larger than 7, 10, 15, 20, 25, or 30 French. In some embodiments, the sheath  3016  is between 7 and 30 French, between 7 and 25 French, between 7 and 20 French, or between 7 and 15 French. In some embodiments, the lumen  3054  is sized to receive a catheter  3026  that is only slightly smaller, which can allow a lumen of the catheter  3026  to be relatively large and permit ready passage therethrough of cored pieces of blockage material (e.g., food). For example, in some embodiments, the sheath  3016  is 12 French, which can be fairly easy for many patients to swallow, and the catheter  3026  can be as large as 10 or 11 French. In various embodiments, the catheter  3026  can be no less than 4, 6, 8, 10, or 12 French, or may be between 4 and 12 French. 
       FIG. 28A  depicts the distal end  3012  of the sheath assembly  3002  when the positioning element  3018  is in the undeployed state. As can be seen, the balloon  3019  can define an outer diameter that may be only slightly greater than an outer diameter of more proximal portions of the sheath  3016  when in the undeployed state. In other embodiments, the outer diameter of the undeployed balloon  3019  may be the same as or slightly smaller than that of an adjacent portion of the sheath  3016 . In the illustrated embodiment, the instrument delivery lumen  3054  extends through an axial center of the balloon  3019 . Stated otherwise, the balloon  3019  encompasses a longitudinal axis of the sheath  3016 . 
       FIG. 28B  depicts the distal end  3012  of the sheath assembly  3002  when the positioning element  3018  has been transitioned to the deployed state, such as by introduction of an inflation fluid into the balloon  3019  via the inflation channel or inflation lumen  3066  (see  FIG. 27 ). For example, as is clear from the foregoing disclosure, the inflation fluid can be introduced into the balloon  3019  by coupling a fluid-filled syringe or other medical fluid delivery device with the connector  3062 , ensuring that the stopcock  3064  is in the opened state, and delivering fluid from the medical fluid delivery device through the connector  3062 , through the stopcock  3064 , through the inflation lumen  3066 , and into the balloon  3019 . Moreover, the balloon  3019  can be maintained in the deployed state by closing the stopcock  3064 . As can be seen in  FIG. 28B , the balloon  3019  can define an outer diameter that is significantly greater than an outer diameter of more proximal portions of the sheath  3016  when in the deployed state. 
     In certain embodiments, the balloon  3019  can be rotationally symmetrical when inflated. In further instances, the balloon  3019  can be configured to be rotationally symmetrical throughout inflation. Certain of such arrangements can substantially center the lumen  3054  relative to the esophagus. The inflated balloon  3019  also can anchor the lumen  3054  relative to the esophagus, or stated otherwise, the inflated balloon  3019  can stabilize the lumen  3054  relative to the esophagus to ensure the catheter tip  3023  does not come into contact with the esophageal wall. In certain embodiments, such an arrangement can ensure that the distal tip  3023  of the catheter  3026  does not come into contact with, or otherwise remains distanced from, the esophageal wall when the distal tip  3023  is advanced past the distal tip of the sheath  3016 . Other arrangements are also contemplated. For example, in some embodiments, the lumen  3054  may not be centered relative to the esophagus. For example, in some embodiments, the positioning element  3018  may anchor the sheath  3016  such that a longitudinal axis thereof runs parallel to a central longitudinal axis of the esophagus. However, it may be desirable for the lumen  3054  to be centered relative to the esophagus to minimize the chances of contacting the esophagus wall with the distal tip  3023  of the catheter  3026  in any or all radial directions. 
     In some embodiments, the balloon  3019  is semi-compliant or non-compliant. For example, the balloon  3019  may expand to a predetermined size via application of a first amount of pressure therein, and thereafter may either expand only minimally or not at all upon further addition of pressure therein. In other or further embodiments, a portion of the balloon  3019  may be semi-compliant or non-compliant and another portion thereof can be compliant. For example, in some embodiments, a central portion of the balloon  3019  can be semi-compliant or non-compliant and one or more of a proximal or distal end of the balloon may be compliant. When the balloon  3019  is inflated to a predetermined pressure, the semi- or non-compliant portion defines a predetermined diameter, and if further pressure is applied, the proximal and/or distal ends may expand (e.g., longitudinally) to preserve the predetermined diameter of the balloon. Any suitable configuration of the balloon  3019  is contemplated. In some instances, it can be desirable for the balloon  3019  to not expand to a circumference or diameter that would damage the esophagus of the patient. On the other hand, it can be desirable for the balloon to expand by a sufficient amount to securely position the cutting distal tip  3023  of the catheter  3026  away from the esophageal wall. In some instances, the balloon can press against the esophageal wall around a full periphery of the balloon and/or around a full periphery of the inner surface of the esophageal wall. 
       FIG. 29  depicts the proximal end  3020  of the catheter assembly  3004  in greater detail than is shown in  FIG. 25 . As previously discussed, the catheter hub  3024  includes a handle  3040  and a suction port  3042 . In the illustrated embodiment, the suction connector  3028  is positioned at a proximal end of the handle  3040 . Other positions for the suction connector  3028  are contemplated. 
       FIG. 30  is a cross-sectional view of the catheter  3026 . In the illustrated embodiment, the catheter  3026  includes a body  3070  and a lubricious layer  3072  at an internal surface thereof. The lubricious layer  3072  can define a lumen  3074  through which morsels of food that are removed from an impacted food bolus can pass. 
     The body  3070  can be formed of a material and/or can have a sidewall thickness that is sufficient to provide the catheter  3026  with desirable amounts of columnar or other strength. For example, in various embodiments, the catheter  3026  can resist compression, crushing, kinking, and/or other deformation that could undesirably alter the shape of the lumen  3074  in a manner that could interfere with passage therethrough of food morsels. Various suitable materials for the catheter  3026  are disclosed above. These and or other suitable materials are contemplated. For example, in some embodiments, the material comprises a relatively hard durometer. In other or further embodiments, the material may comprise a braided configuration. In some embodiments, the catheter  3026  may be more compliant than the sheath  3016 . For example, in some embodiments, the sheath  3016  can protect the catheter  3026  from kinking or other undesired deformation. In some embodiments, the body  3070  can maintain its shape when significant suction forces are present within the lumen  3074 . 
     The lubricious layer  3072  can be formed of any suitable material, and may have a low coefficient of friction or exhibit other physical properties that permit food morsels to pass readily by without sticking, adhering, or otherwise being stopped. In various embodiments, the lubricious layer  3072  can include one or more of PTFE or HDPE. In other embodiments, the lubricious layer  3072  may be omitted. For example, in some embodiments, the lumen  3074  is sufficiently large to reduce the chances of food morsels being stuck thereto during use. Stated otherwise, the lumen  3074  is sufficiently large to inhibit the food morsels from being stuck thereto during use. 
     In certain embodiments, an outer diameter of the body  3070  is sufficiently smaller than an inner diameter of the sheath  3016  to permit the body  3070  to readily pass through the sheath  3016 . In some embodiments, the outer and inner diameters are sufficiently similar, however, such that the sheath  3016  can significantly limit lateral movement of the catheter  3026 . 
       FIG. 31  depicts the distal end  3022  of the catheter assembly  3020  in greater detail than is shown in  FIG. 25 . In the illustrated embodiment, an inner diameter of the lumen  3074  is substantially constant along a full length of the catheter  3026 . In other embodiments, such as those described in detail above, a diameter of the catheter  3026  may be narrower near the distal tip  3023  than it is along a proximal length thereof. An enlarged diameter along the proximal length may facilitate suctioning of food morsels through the catheter  3026  after those morsels are cored from the food bolus via the tip  3023 . 
     In the illustrated embodiment, the distal tip  3023  defines a sharp edge. The edge is formed in part by a back bevel  3076  at an outer surface of the catheter  3026 . Other cutting arrangements are contemplated, including those discussed further below. 
       FIG. 32A  is an early stage in an illustrative method of using the system  3000 . In the illustrated stage, the distal end  3012  of the sheath assembly  3002  is inserted into the esophagus  3090  of a patient. For example, the distal end  3012  of the sheath assembly  3002  can be inserted through the mouth of the patient and into the esophagus, as disclosed elsewhere herein. The distal tip of the sheath  3016  is advanced toward a foreign body  3092  that is lodged in the esophagus  3090 . In the illustrated method, the foreign body  3092  is an impacted bolus of food, and will be referred to as such hereafter. 
       FIG. 32B  is a subsequent stage in the illustrative method. In the illustrated stage, the sheath  3016  has been advanced distally a sufficient distance to bring the distal tip of the sheath assembly  3002  into contact with a proximal end  3098  of the food bolus  3092 . In some instances, the procedure is performed blind. As apparent from the present disclosure, performing a procedure “blind” means that the procedure is not visualized, such as via a camera of an endoscope, under fluoroscopy, etc. The practitioner may be able to discern this contact with the food bolus  3092  via tactile feedback. For example, the practitioner can sense that the food bolus  3092  has been reached by a sudden increase in resistance to distal advancement of the sheath  3016 . 
       FIG. 32C  is a subsequent stage in the illustrative method. In the illustrated stage, the positioning element  3018  is deployed into contact with the esophagus  3090 . For example, as apparent from other disclosures herein, an inflation device (e.g., a syringe) can be coupled with the inflation port  3060  and, with the stopcock  3064  in the open state, an inflation fluid (e.g., air) can be delivered from the inflation device into the balloon  3019  to deploy the balloon  3019 . Once the balloon  3019  has been deployed, the stopcock  3064  can be closed to maintain the balloon  3019  in the deployed state. In the illustrated embodiment, the positioning element  3018 , or balloon  3019 , substantially centers the lumen  3054  relative to the esophagus  3090 . 
       FIG. 32D  is a subsequent stage in the illustrative method in which the distal tip  3023  of the catheter  3026  is advanced through the sheath  3016  and brought into contact with the proximal end  3098  of the food bolus  3092 . In some instances, suction may be applied via the catheter  3026  throughout advancement of the catheter  3026  toward the food bolus  3092 . In other instances, the practitioner may utilize tactile feedback to determine that contact has been made with the food bolus  3092 , and may then instigate suction. The suction can draw a portion of the food bolus  3092  into the lumen  3074   
       FIG. 32E  is a subsequent stage in the illustrative method in which a morsel of food  3094  from the food bolus  3092  is cut, or cored, by the distal tip  3023  of the catheter  3026  and is drawn into the lumen  3074  of the catheter  3026 . In some embodiments, the catheter  3026  defines a length that is only slightly longer than a length of the sheath  3016 . This maximum advanced length of the catheter  3026  may be delimited to reduce the chances of the distal tip  3023  coming into contact with the esophageal wall. In various embodiments, the distal tip  3023  is limited from moving past the distal tip of the sheath  3016  by a distance of no greater than 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, or 2.0 inches. Stated otherwise, movement of the catheter  3026  relative to the sheath  3016  is delimited to inhibit the distal tip of the catheter  3026  from coming into contact with the esophageal wall when the distal end of the catheter  3026  is extended to its distalmost orientation relative to the sheath  3016 . 
     In view of at least the foregoing disclosure and the drawings, it is apparent that delimitation of the maximum advanced length can be due to interaction of the proximal end  3020  of the catheter assembly  3004  and the proximal end  3010  of the sheath assembly  3002 . For example, in the illustrated embodiment, the distal end of the catheter  3026  is attached to the catheter hub  3024 , which defines an enlarged diameter, as compared with a diameter of the catheter  3026 , at the distal end of the catheter hub  3024 . The catheter hub  3024  can interact with the sheath hub  3014  to delimit the maximum advanced length to which the catheter  3026  can extend past the distal end of the sheath  3016 . In particular, the catheter  3026  of the catheter assembly  3004  can be advanced distally through the guide  3052  of the sheath hub  3014  of the sheath assembly  3002 , whereas the distal face of the catheter hub  3024  can interfere with a proximal face of the sheath hub  3014  or with the tapered surface of the guide  3052  to delimit the distal movement of the catheter  3026 . 
     More generally, the catheter assembly  3004  can define a stopping region  3047  (see  FIG. 29 ) having an enlarged diameter, relative to a diameter of a working length of the catheter  3026 . This stopping region  3047  can, for example, be defined at least in part by the catheter hub  3024 . In the illustrated embodiment, the stopping region  3047  is defined entirely by a distal end of the catheter hub  3024 . The stopping region  3047  can interfere with a portion of the sheath hub  3014  to delimit distal movement of the catheter  3026 . In the illustrated embodiment, the portion of the sheath hub  3014  with which the stopping region  3047  (e.g., the distal end of the catheter hub  3014 ) can interfere is the proximal face of the sheath hub  3014  or a proximal end of the guide  3052 . 
       FIG. 32F  is a subsequent stage in the illustrative method in which the morsel of food  3094  has detached from the food bolus  3092  and is suctioned through the lumen  3074  of the catheter  3026 . 
       FIG. 32G  is a subsequent stage in the illustrative method in which the catheter  3026  is withdrawn from the sheath  3016 . In some instances, the catheter  3026  is only partially withdrawn into the lumen  3054  so as not to inadvertently contact the esophagus. In other instances, the catheter  3026  may be fully withdrawn. 
     In some instances, a sufficient amount of material from the food bolus may have been withdrawn at this point for at least a portion of the food bolus to collapse by an amount sufficient to allow the food bolus to pass naturally into the stomach of the patient. Such passage may result in sudden relief to the patient, which can indicate that no further coring or clearing is needed. In some instances, the sheath  3016  and the catheter  3026  may be withdrawn together, or one after the other. 
     In other instances, it may be desirable to continue coring the food bolus  3092 . Accordingly, in some instances, the procedure may continue, such as by positioning the system  3000  more distally within the esophagus  3090 . 
     In some instances, the system  3000  can clear the food bolus  3092  without passing any portion of the system  3000  beyond a distal end of the food bolus  3092 . In other or further instances, the system  3000  can clear the food bolus  3092  without passing any portion of the system  3000  completely through the food bolus  3092 . 
       FIG. 32H  is a subsequent stage in one such further illustrative method in which further coring of the food bolus is desired. In the depicted stage, the positioning element  3018  is returned to the undeployed configuration to permit ready movement of the sheath  3016  relative to the esophageal wall. 
       FIG. 32I  is a subsequent stage in the further illustrative method in which the distal end of the sheath  3016  has been advanced to a more distal position within the esophagus  3090 . The proximal end  3098  of the cored food bolus has been reshaped in the absence of the suctioned-off food morsel  3094 . 
       FIG. 32J  is a subsequent stage in the further illustrative method in which the positioning element  3018  is deployed again into contact with the esophagus  3090 . Such repositioning can, in certain instances, permit further coring of the food bolus  3092  with little or no risk of the distal end of catheter coming into contact with the esophagus. 
       FIG. 32K  is a subsequent stage in the further illustrative method in which the distal tip  3023  of the catheter  3026  is again brought into contact with the proximal end  3098  of the food bolus  3092  for further coring thereof. 
     When coring is completed, the catheter  3026  can be drawn into the sheath  3016  to shield the sharpened distal end of the catheter  3026 , or may be fully withdrawn from the sheath assembly  3002 . The balloon  3019  can be deflated out of contact with the esophagus and fully or partially returned to the undeployed state. For example, the stopcock  3064  can be opened to release inflation fluid (e.g., air) from the balloon  3019 . The sheath  3016  may then be withdrawn from the patient. 
       FIG. 33A  is an elevation view of a distal end of another embodiment of a sheath assembly  3102  that includes a differently shaped positioning element  3118  in an undeployed state. In some embodiments, the positioning element  3118  comprises a balloon that is compressed, folded, or otherwise formed into a low-profile arrangement such as that depicted in  FIG. 33A  so as to have a substantially cylindrically shaped outer surface that may be only slightly larger than a cylindrical outer surface of the sheath to which it is attached. 
       FIG. 33B  is another elevation view of the distal end of the sheath assembly  3102  that depicts the positioning element  3118  in a deployed state in which the positioning element  3118  is substantially shaped as a frustocone. Other configurations of the deployed positioning element  3118  are contemplated. As with the positioning element  3018  described above, in certain embodiments, the positioning element  3118  can be radially symmetrical. 
       FIGS. 34, 35A, and 35B  depict various views of another embodiment of a sheath assembly  3202  that includes a pressure regulation valve  3211 . The pressure regulation valve  3211  can regulate a pressure within a positioning member  3218 , such as an inflation balloon  3219 . For example, the pressure regulation valve  3211  can ensure that a pressure within the inflation balloon  3219  does not exceed a preset maximum value. Such an arrangement may be configured to ensure that excess pressure that might injure or otherwise negatively impact the esophagus is not applied to the esophagus. As indicated in  FIG. 34 , the sheath assembly  3202  can be a component in another embodiment of a blockage clearing system  3200 , such as the blockage clearing system  3000  described above. 
     The pressure regulation valve  3211  is depicted in fluid communication with a pressurization port  3260 , which may also be referred to as an inflation port  3260 . The pressure regulation valve  3211  is also depicted in fluid communication with an inflation lumen  3266 . The pressure regulation valve  3211  is operationally positioned between the inflation port  3260  and the portion of the inflation lumen  3266  that is defined by a sheath  3216 . Stated otherwise, the pressure regulation valve  3211  is in line with inflation port  3260  and is in line with the portion of the inflation lumen  3266  defined by the sheath  3216 . In particular, in the illustrated embodiment, the pressure regulation valve  3211  is in line with each of the inflation port  3260  and the inflation lumen  3266 , and further, is positioned between the inflation port  3260  and the inflation lumen  3266 . The pressure regulation valve  3211  is coupled with a hub  3214 . In particular, the pressure regulation valve  3211  is coupled to the hub  3214  via an extender  3267 . 
       FIG. 35A  depicts the positioning element  3218  in an undeployed state.  FIG. 35B  depicts the positioning element  3218  in a deployed state.  FIG. 35C  depicts the positioning element  3218  in a further state of operation in which the positioning element has been maintained in the deployed state at a substantially constant pressure via the pressure regulation valve  3211 , despite attempts to further pressurize the positioning element via the pressurization port  3260 . 
       FIG. 36  is an elevation view of a proximal end of another embodiment of a catheter assembly  3304  that, in some instances, may be used with a system such as the system  3000  discussed above; in other or further instances, may be used with an endoscope; or in still other instances, may be used without a sheath or endoscope. The catheter assembly  3304  can include a hub  3324  similar to the hub  3024  discussed above. For example, the catheter assembly  3304  includes a handle  3340  having a different gripping arrangement (more akin to a gun or drill) and a similar suction port  3342 . The hub  3324  can further include an actuator or inflation port  3360 , such as the inflation port  3060  discussed above with respect to the sheath assembly  3002 . 
       FIG. 37  is a cross-sectional view of a catheter  3326  of the catheter assembly  3304 . The catheter  3326  can resemble the catheter  3026  described above in many respects, but may further include an inflation channel or inflation lumen  3366 , such as the like-numbered lumen  3066  discussed above with respect to the sheath  3016 . 
       FIG. 38A  is an elevation view of a distal end of the catheter assembly  3304  in which a positioning element  3318  is depicted in an undeployed state. The positioning element  3318  can function in the same manner as other positioning elements described above, and may be in fluid communication with the inflation lumen  3366 . The positioning element  3318  can distance a distal tip  3323  of the catheter  3326  from the esophagus wall when deployed. For example, the positioning element  3318  may be symmetrical and/or may center the distal tip  3323  from the esophagus. In the illustrated embodiment, the distal tip  3323  is positioned at a distance distally from the distal end of the positioning element  3318 . 
       FIG. 38B  is another elevation view of the distal end of the catheter assembly  3304  in which the positioning element  3318  is depicted in a deployed state, such as described with respect to various other embodiments above. 
       FIG. 39A  is an elevation view of a distal end of another embodiment of a catheter assembly  3404  that includes a differently shaped positioning element  3418  that is depicted in an undeployed state.  FIG. 39B  is another elevation view of the distal end of the catheter assembly  3404  that depicts the positioning element  3418  in a deployed state. In some embodiments, the catheter assembly  3404  is used to clear an impacted food bolus in manners such as described above, but without a sheath. In other embodiments, the catheter assembly  3404  is used with a sheath, such as the sheath  3016 , in manners such as described above. For example, both the sheath  3016  and the catheter assembly  3404  can include inflatable positioning members that inhibit contact between the esophagus and the catheter. In still other or further embodiments, the catheter assembly  3404  can instead be inserted into the esophagus of a patient through the working channel of an endoscope. The positioning element  3418  can be advanced past a distal end of the endoscope and deployed into contact with the esophagus to prevent inadvertent contact of the distal tip of the catheter to the esophageal wall. 
       FIG. 40A  is an elevation view of a distal end of another embodiment of a catheter assembly  3504  that includes a differently shaped and differently oriented positioning element  3518  that is depicted in an undeployed state.  FIG. 40B  is another elevation view of the distal end of the catheter assembly  3504  that depicts the positioning element in a deployed state. When deployed, the positioning element  3518  is substantially donut-shaped. The positioning element  3518  is also closer to the distal end of the catheter assembly  3504 . In some embodiments, the catheter assembly  3504  can be particularly well-suited for use with a sheath and/or an endoscope, such as, for example, those previously described. The positioning element  3518  may be advanced just beyond a distal tip of the sheath or endoscope before being deployed, in some instances. 
       FIG. 41  is an elevation view of a distal end of another embodiment of a catheter assembly  3604  that depicts a distal tip  3623  of a catheter  3626  that includes an internal bevel  3676 . For example, the internal bevel  3676  may be formed as a conical chamfer. 
       FIGS. 42 and 43  depict a distal end of another embodiment of a catheter assembly  3704  that includes a catheter  3726  that has a distal tip  3723  that is substantially flat. The catheter assembly  3704  includes a cutting element  3775 , such as a blade, that is recessed from the distal tip  3723  within a lumen of the catheter  3726 . The cutting element  3775  includes a cutting edge  3777 , which is substantially circular in the illustrated embodiment. The cutting element  3775  is attached to the catheter  3726  via a plurality of brackets or supports  3779 . A cutting area of the cutting edge  3777  can be smaller than an inner diameter of a lumen of the catheter  3726 . 
       FIG. 44  is an elevation view of a distal end of another embodiment of a catheter assembly  3804  that depicts a distal tip  3823  of a catheter  3826  that is substantially rounded and that includes a cutting element  3875  that is recessed from the distal tip  3823  within a lumen of the catheter. The catheter assembly  3804  further includes a positioning element or centering balloon  3819 , which can function similarly to other embodiments described herein. The rounded tip  3823  may be substantially atraumatic to the esophagus. The recessed cutting element  3875  may further aid in preventing inadvertent damage to the esophagus. The centering balloon  3819  may likewise prevent inadvertent damage to the esophagus when deployed. As with other embodiments described herein, the catheter assembly  3804  may be used with or without a sheath or endoscope, in various embodiments. Catheter assemblies such as the assembly  3804  may also be referred to as catheter systems. 
       FIG. 45  is an elevation view of another embodiment of a blockage clearing system  4000  that can resemble blockage clearing systems described above (e.g., the systems  3000 ,  3200 ) in certain respects. Accordingly, like features are designated with like reference numerals, with the leading digits incremented to “40.” Relevant disclosure set forth above regarding similarly identified features thus may not be repeated hereafter. Moreover, specific features of the system  4000  may not be shown or identified by a reference numeral in the drawings or specifically discussed in the written description that follows. However, such features may clearly be the same, or substantially the same, as features depicted in other embodiments and/or described with respect to such embodiments. Accordingly, the relevant descriptions of such features apply equally to the features of the system  4000  and components thereof. Any suitable combination of the features and variations of the same described with respect to the systems  3000 ,  3200  can be employed with the system  4000 , and vice versa. More generally, any suitable combination of like-numbered components herein is contemplated. Thus, for example, any of the positioning element arrangements  3018 ,  3118 ,  3218 ,  3318 ,  3418 ,  3518 ,  3819  disclosed above, and the positioning element arrangements described hereafter, may be used in place of any of the other positioning elements, mutatis mutandis. This pattern of disclosure applies equally to further embodiments depicted in subsequent figures and described hereafter, wherein the leading digits may be further incremented. 
     The system  4000  is shown in a pre-use, undeployed, packaged, or insertion state. In particular, the system  4000  is shown in a state in which it may be packaged, or stated otherwise, in a state in which it exists when removed from packaging by a user (e.g., medical practitioner) for insertion into a patient. The system  4000  can include a sheath assembly  4002  and a catheter assembly  4004 , such as like-numbered features previously disclosed. The sheath assembly  4002  is discussed further below with respect to at least  FIGS. 46-50 , and the catheter assembly  4004  is discussed further below with respect to at least  FIGS. 51-53 . 
     The system  4000  further includes a retainer or spacer  4080  that can maintain a fixed relative orientation of the sheath assembly  4002  and the catheter assembly  4004 . Stated otherwise, the spacer  4080  can maintain a fixed longitudinal relationship, such as a fixed longitudinal separation, between hubs of the sheath assembly  4002  and the catheter assembly  4004 . Maintenance of such a fixed relationship between the hubs can likewise maintain a fixed longitudinal relationship between the distal tips of the sheath assembly  4002  and the catheter assembly  4004 . For example, as further discussed below, the spacer  4080  can ensure that a distal tip of the catheter assembly  4004 , which may comprise a sharpened cutting tip, is positioned at an interior of the sheath assembly  4004  (e.g., is proximally recessed relative to a distal tip of the sheath assembly  4004 ) when the spacer  4080  is in place. Such an arrangement may be useful to ensure that the cutting surface of the catheter does not inadvertently come into contact with the anatomy of a patient as the system  4000  is being introduced into the patient (e.g., into the esophagus of the patient). Accordingly, in some instances, the system  4000  may be provided in the assembled state shown with the spacer  4080  in place. For example, the system  4000  may be packaged with the spacer  4080  positioned in engagement with the sheath assembly  4002  and the catheter assembly  4004 . 
     In the illustrated embodiment, the spacer  4080  is formed as a clip  4082  that is selectively attachable to and detachable from specific regions of the sheath assembly  4002  and the catheter assembly  4004 . In other embodiments, the clip  4082  may only be selectively detachable from the sheath assembly  4002  and the catheter assembly  4004 . For example, in some embodiments, portions of the clip  4082  may be permanently attached to the sheath assembly  4002  and the catheter assembly  4004 , respectively, and a further portion of the clip  4082  may permanently detach from the portions that are attached to the sheath assembly  4002  and the catheter assembly  4004  to permit relative movement of the sheath assembly  4002  and the catheter assembly  4004 . In some instances, the clip  4082  may be provided with the system  4000  in an initial or pre-deployment state (e.g., a packaged state), and may be used during an initial insertion of the system  4000  into the patient and into contact with a blockage, such as a food impaction. The detachable portion of the clip  4082  (e.g., the clip  4082  in its entirety or a detachable portion thereof) may then be removed to permit relative longitudinal movement of the sheath assembly  4002  and the catheter assembly  4004 , as discussed further below. 
       FIG. 46  is an elevation view of the sheath assembly  4002  in a deployed state. As with other sheath assemblies previously discussed (e.g., the sheath assemblies  3002 ,  3202 ), the sheath assembly  4002  can include an inflation port  4060 , which can include a connector  4062 , such as a luer fitting  4063 . The inflation port  4060  can further include a stopcock  4064 , which can be transitioned between open and closed states via a knob or lever  4065 . The inflation port  4060  can be formed of any suitable materials. For example, in some embodiments, the inflation port  4060  comprises polycarbonate. 
     As with other embodiments described herein, the inflation port  4060  can be coupled with a sheath hub  4014  in any suitable manner. In the illustrated embodiment, the inflation port  4060  is coupled to an extender  4067 , such as tubing of any suitable construct, and the extender  4067  is coupled to the hub  4014 . The extender tubing can comprise any suitable material. For example, in some embodiments, the tubing comprises TYGON®, available from Saint-Gobain Performance Plastics. The extender  4067  can be attached to a connector portion of the stopcock  4064  in any suitable manner. 
     The hub  4014  can include a housing  4050 , which is discussed further below with respect to  FIGS. 47 and 48 . In some embodiments, a pressure regulation valve  4011  is coupled with the housing  4050 . In particular, in the illustrated embodiment, the pressure regulation valve  4011  is directly connected to the housing  4050 . The hub  4014  can further be coupled with a sheath  4016  and a strain relief sleeve  4015 . The pressure regulation valve  4011  may also be referred to as a pressure regulator. 
     As with other embodiments disclosed herein, the sheath  4016  can be coupled with a positioning element  4018 , such as an inflatable balloon  4019 . In some embodiments, the sheath  4016  can include a soft or atraumatic distal tip  4013 . 
     As with the inflation port  3060  discussed above, the inflation port  4060  may also be referred to as an actuator. As further discussed below, the inflation port  4060  is configured to be actuated to achieve deployment of the positioning element  4018 , and can be further actuated to achieve retraction of the positioning element  4018 . 
     With reference again to  FIG. 45 , in some embodiments, the sheath  4016  can include one or more depth indicia or indicators  4084 . The indicators  4084  can comprise any suitable marking or other signaling element to provide a visual cue to a user to indicate a depth to which the distal tip of the sheath assembly  4002  has been inserted into a patient. For example, the one or more indicators  4084  can be printed or may be formed as laser markings. In some embodiments, one of the indicators—for example, the distalmost indicator  4084 —may indicate a minimum depth to which the distal tip of the sheath assembly  4002  should desirably be inserted prior to deployment of the positioning element  4018 . For example, in some embodiments, the minimum depth indicator  4084  is positioned, e.g., 25 centimeters from the distal tip of the sheath  4016 . A practitioner may use the minimum depth indicator  4084  to ensure that the distal tip of the sheath  4016  has been inserted to a sufficient depth past the incisors of the patient, which can ensure that the positioning element  4018  is not deployed within the pharynx of the patient. In various embodiments, the minimum depth indicator  4084  may be closer to or further from the distal tip of the sheath  4016  than 25 centimeters. In some instances, the minimum depth indicator  4084  is selected to ensure that the pharynx of any patient, regardless of patient size or anatomy variation, will be avoided when the positioning element  4018  is deployed. 
     With reference to  FIGS. 47 and 48 , the hub  4014  can include a housing  4050 , which can be formed in any suitable manner. For example, the housing  4050  may be an injection-molded plastic component. In some embodiments, the housing  4050  comprises polycarbonate. 
     The housing  4050  can define a connector  4055  at a proximal end thereof. For example, in some embodiments, the connector  4055  comprises a luer fitting  4056 . The connector  4055  can permit selective coupling with any suitable medical device to provide the medical device with access to an instrument delivery lumen  4054  defined by the sheath  4016  (see  FIG. 49 ). For example, if a practitioner desires to flush the instrument delivery lumen  4054  of the sheath  4016 , a flushing syringe could be coupled with the connector  4055  and fluid dispensed through the instrument delivery lumen  4054 . 
     The connector  4055  portion of the housing  4050  can define an entry passage or guide  4052 . In the illustrated embodiment, the guide  4052  is substantially funnel shaped, which can facilitate insertion of a distal end of a catheter portion of the catheter assembly  4004  into the instrument delivery lumen  4054  of the sheath  4016 . In particular, in the illustrated embodiment, the guide  4052  defines a luer taper that decreases in diameter in the distal direction. 
     The housing  4050  can further define a connector  4057 , such as a flanged or ribbed post, or the like, to which the extender  4067  can be attached in any suitable manner. Similarly, the housing  4050  can define a connector  4058 , such a flanged or ribbed post, or the like, to which the strain relief sleeve  4015  can be attached in any suitable manner. For example, as shown in  FIG. 48 , in the illustrated embodiment, the extender  4067  is fitted over the connector  4057  and the strain relief sleeve  4015  is fitted over the connector  4058  to achieve said attachments. 
     The housing  4050  can define a sheath receptacle  4059  into which a proximal end of the sheath  4016  can be received. The sheath  4016  can be inserted into the sheath receptacle  4059  until the proximal end contacts a ledge at the proximal end of the receptacle. The proximal end of the sheath  4016  thus may be at or slightly below a distal end of the guide  4052  when the sheath  4016  has been secured to the housing  4050 . 
     The housing  4050  can further define an inflation channel or lumen  4066   a  that extends through the connector  4057  and that terminates at and is in fluid communication with the sheath receptacle  4059 . The housing  4050  can further define an inflation channel or lumen  4066   b  that extends from a valve receptacle  4069  to the lumen  4066   a . In particular, the lumen  4066   b  intersects the lumen  4066  at a junction  4061 . Stated otherwise, fluid communication between the lumens  4066   a ,  4066   b  is established at the junction  4061 . The lumens  4066   a ,  4066   b  are in fluid communication with each other and define separate branches of a unitary fluid passageway defined by the housing  4050 . Stated otherwise, the channels  4066   a ,  4066   b  may be considered to be, and may also be referred to as, separate branches of a unitary inflation passageway or inflation lumen  4066 , of which a proximal end is defined by the housing  4050  and a distal end is defined by the sheath  4016 . That is, as with other embodiments herein, and as previously noted, the sheath assembly  4002  can include multiple lumens for expanding the balloon  4019 , including one or more lumens that extend through the sheath  4016 . All of the lumens may be interconnected or in fluid communication with each other, and may collectively define the fluid passageway or inflation lumen  4066 . 
     With reference to  FIG. 49 , in the illustrated embodiment, the sheath  4016  defines two separate inflation lumens  4066   c ,  4066   d  that are each in fluid communication with the inflation lumen  4066   a  defined by the housing  4050  at or near their proximal ends, and further, are in fluid communication with an interior of the balloon  4019  at or near their distal ends. The inflation lumens  4066   c ,  4066   d  define the distal end of the inflation passageway or inflation lumen  4066  of the sheath assembly  4002 . As previously noted, in some embodiments, it can be advantageous for the sheath  4016  to define two or more inflation lumens, such as, for example, for purposes of redundancy in the event that one of the lumens  4066   c ,  4066   d  is inadvertently blocked (e.g., due to kinking of the sheath  4016 ). Thus, even if one lumen  4066   c ,  4066   d  becomes obstructed, the other can permit inflation or deflation of the balloon  4019 . 
     Again, as previously mentioned, the inflation lumen  4066  can be a unitary lumen or fluid pathway or passageway that includes a plurality of interconnected lumens or branches  4066   a ,  4066   b ,  4066   c ,  4066   d . In the illustrated embodiment, the inflation lumens  4066   a ,  4066   b  are connected and in fluid communication with each other at the junction  4061 . Further, the inflation lumens  4066   c ,  4066   d  are in fluid communication with the distal end of the inflation lumen  4066   a  at their proximal ends, and are in fluid communication with an interior of the balloon  4019  at their distal ends. In this manner, a pressure within the balloon  4019  and within any of the inflation lumens  4066   a ,  4066   b ,  4066   c ,  4066   d  can be substantially the same at any given time. Stated otherwise, the inflation lumens  4066   a ,  4066   b ,  4066   c ,  4066   d  and the balloon  4019  can be pressurized substantially in unison, or may increase in pressure substantially concurrently and/or substantially at the same rate during deployment of the balloon  4019 . 
     For example, in some instances, an air-filled syringe can be coupled with the connector  4062 . The stopcock  4064  can be oriented in an open state (e.g., the lever  4065  can be rotated to the open state). To deploy the balloon  4019 , a plunger of the syringe can be depressed. This can cause air to flow from the syringe, through the stopcock  4064 , through the extender  4067 , into the inflation lumen  4066   a , and from the inflation lumen  4066   a  into the inflation lumen  4066   b , and further, into the inflation lumens  4066   c ,  4066   d  of the sheath  4016  and from thence into the balloon  4019 . Once air has passed into all of these cavities, pressurization in each of the branches of the inflation lumen  4066  and within the balloon  4019  can proceed substantially in unison as more air is urged from the syringe and, after full deployment of the balloon  4019  (which, in some embodiments, may be non-compliant or semi-compliant) is compressed within a fixed-volume inflation fluid receptacle defined by the inflation lumen  4066  and the expanded balloon  4019 . 
     With reference again to  FIGS. 47 and 48 , the pressure regulation valve  4011  is attached to the housing  4050  within the valve receptacle  4069 . In some instances, the pressure regulation valve  4011  may be secured in place via an adhesive. The pressure regulation valve  4011  can be of any suitable variety. For example, the pressure regulation valve  4011  can comprise a check valve that is configured to permit passage therethrough of a fluid (e.g., air) at or above a cracking pressure. Any suitable commercially available or other variety of check valve is contemplated. For example, in some embodiments, a commercially available cartridge check valve or pressure relief valve is used. The check valve  4011  is positioned such that an entry port thereof  4017   a  is in fluid communication with the inflation channel  4066   b , and hence with the inflation channel  4066   a . More generally, the entry port  4017   a  of the check valve  4011  is in fluid communication with the inflation passageway or inflation lumen  4066  of the sheath assembly  4002 . Further, in the illustrated embodiment, the pressure regulation valve  4011  is oriented such that an exit port  4017   b  thereof is in fluid communication with an environment external to the housing  4014 . The pressure regulation valve  4011  thus can leak inflation fluid (e.g., air) to the environment when a threshold pressure—i.e., the cracking pressure—is reached or exceeded within the inflation lumen  4066  and within the balloon  4019 . 
     Accordingly, the pressure regulation valve can regulate a pressure within the balloon  4019 . For example, the pressure regulation valve  4011  can ensure that a pressure within the inflation balloon  4019  does not exceed a preset maximum value, which corresponds with the cracking pressure of the valve. Such an arrangement may be configured to ensure that excess pressure that might injure or otherwise negatively impact the esophagus is not applied to the esophagus. 
     The pressure regulation valve  4011  is depicted as being in fluid communication with the pressurization or inflation port  4060 . In particular, with reference to  FIGS. 46 and 48 , the pressure regulation valve  4011  is in fluid communication with the inflation lumen  4066  ( FIG. 48 ), the inflation lumen  4066  is in fluid communication with the tubing  4067  ( FIG. 48 ), and the tubing  4067  is in fluid communication with the inflation port  4060  ( FIG. 46 ). The pressure regulation valve  4011  is operationally positioned between the inflation port  4060  and the portion of the inflation lumen  4066  defined by the sheath  4016  (e.g., the inflation lumens  4066   c ,  4066   d , as shown in  FIG. 49 ). Stated otherwise, the pressure regulation valve  4011  is in line with the inflation port  4060  and is in line with the portion of the inflation lumen  4066  defined by the sheath  4016  (e.g., the inflation lumens  4066   c ,  4066   d ). In particular, in the illustrated embodiment, the pressure regulation valve  4011  is fluidly coupled to the inflation lumen  4066  at a position that is in line with or is between the inflation port  4060  and the portion of the lumen  4066  that is defined by the sheath  4016  (e.g., the inflation lumens  4066   c ,  4066   d ). 
     The pressure regulation valve  4011  is coupled with the hub  4014 . In particular, in the illustrated embodiment, the pressure regulation valve  4011  is directly attached to the hub  4014 . 
     Any suitable cracking pressure of the pressure regulation valve  4011  is contemplated. The cracking pressure may be relatively low to ensure that the balloon  4019  does not deform the esophagus, does not significantly deform the esophagus, or does not deform the esophagus beyond an acceptable amount (e.g., an amount less than that at which injury might occur). In various embodiments, the cracking pressure, which may also be referred to as the threshold pressure, is no greater than 3 psi, 4 psi, or 5 psi. In one embodiment, the cracking pressure is about 4.5 psi (e.g., may be set at 4.56 psi). In other embodiments, higher cracking pressures may be used, such as cracking pressures no greater than 6, 7, or 8 psi. 
     One or more of the connections previously described with respect to the sheath assembly  4002  may be further secured with adhesive. For example, any suitable light curing adhesive is contemplated, including, without limitation, MD 204-CTH-F flexible catheter-bonding adhesive, available from Dymax. For example, adhesive may be used to bond the connections between the extender  4067  and each of the stopcock  4060  and the housing  4050 , between the sheath  4016  and the housing  4050 , between the valve  4011  and the housing  4050 , etc. 
     With reference to  FIGS. 46 and 48 , the strain relief sleeve  4015  can be positioned over a proximal portion of the sheath  4016  and over the connector  4058  at the distal end of the housing  4050 . In some embodiments, the strain relief sleeve  4015  may be heat shrunk in place. Any suitable material for the strain relief sleeve  4015  is contemplated. For example, in some embodiments, the strain relief sleeve  4015  can comprise a polyolefin. 
     The strain relief sleeve  4015  can reinforce a proximal end of the sheath  4016 . For example, in some instances, the strain relief sleeve  4015  can contribute to a columnar strength of the sheath  4016  and can stiffen the sheath  4016 . In some embodiments, this stiffening can facilitate insertion of the sheath  4016  into the esophagus of the patient, such as in instances where the sheath  4016  is relatively compliant. In other or further instances, the strain relief sleeve  4015  can inhibit or prevent kinking of the sheath  4016 , such as kinking that might otherwise close one or more of the inflation lumens  4066   a ,  4066   b . In some instances, the sheath  4016  is sufficiently long to cover and reinforce regions of the sheath  4016  that may be most prone to bending or kinking, such as a region at or near the connector  4058  and/or a region (which may be the same or a different region) at or near a portion of the sheath  4016  that undergoes maximum bending during insertion of the sheath  4016  into the esophagus, such as to conform to the anatomy between the mouth and the esophagus. 
     With reference to  FIG. 49 , the sheath  4016  can be formed in any suitable manner. For example, in some embodiments, the sheath  4016  comprises a tri-lumen extrusion. The sheath  4016  can comprise any suitable material, as previously discussed. In the illustrated embodiment, the sheath  4016  comprises a thermoplastic elastomer, such as PEBAX®. For example, in some embodiments, the sheath  4016  comprises PEBAX® 5533 SA 01 MED. In other or further embodiments, the sheath  4016  can comprise nylon 12 or PEBAX® 7233. 
     With reference to  FIG. 50 , the atraumatic tip  4013  can be formed in any suitable manner. The tip  4013  can be formed of a material that is softer than the remainder of the sheath  4016 . For example, in some embodiments, the sheath  4016  comprises a thermoplastic elastomer, such as PEBAX®, which could be a softer version than is used for the remainder of the shaft, such as, for example, PEBAX® 3533 SA 01 MED. Any suitable manufacturing techniques for forming the tip  4013  are contemplated, such as, for example, reflowing and tipping. 
     With reference again to  FIGS. 47 and 48 , the proximal end of the sheath  4016  can be positioned within the receptacle  4059  such that both lumens  4066   c ,  4066   d  are oriented toward the inflation lumen  4066   a  defined by the housing  4050 . One or more openings  4090  can be formed through the sidewall of the sheath  4016  into the lumens  4066   c ,  4066   d  in a region that aligns with the inflation lumen  4066   a  of the housing to fluidly couple the lumen  4066   a  with the lumens  4066   c ,  4066   d . The one or more openings  4090  can be formed in any suitable manner. For example, in some instances, a fixture that includes one or more blades can retain the unfinished sheath  4016  therein and slice through a portion of the sidewall of the sheath  4016  to provide access to each lumen  4066   c ,  4066   d  individually (e.g., by forming two longitudinal slices) or to provide access to both of the lumens  4066   c ,  4066   d  collectively, such as via a single cut through the sidewall that provides fluid communication into each of the lumens  4066   c ,  4066   d.    
     As previously discussed, in some embodiments, the sheath  4016  is formed as a thin-walled triple-lumen extrusion having a cross-section such as that depicted in  FIG. 49 . In some embodiments, the lumens  4066   c ,  4066   d  are closed at their proximal and distal ends in any suitable manner, thus permitting the lumens  4066   c ,  4066   d  to hold a fluid (e.g., air) therein and withstand pressure increases, such as previously discussed. The proximal and distal ends of the lumens  4066   c ,  4066   d  can be closed or sealed, e.g., so as to be fluid-tight and pressure-resistant, in any suitable manner. For example, in some embodiments, the sidewall of the extrusion in the region of the proximal and distal ends of the lumens  4066   c ,  4066   d  is heated or reflowed and reshaped to close off the proximal and distal ends of the lumens  4066   c ,  4066   d.    
     With reference to  FIG. 50 , one or more openings (not shown) can be formed through the sidewall of the sheath  4016  into the lumens  4066   c ,  4066   d  in a region that is internal to an inflatable portion of the balloon  4019 . The one or more openings can be formed in manners such as discussed above with respect to the one or more openings  4090  ( FIG. 48 ). Accordingly, the interior of the balloon  4019  can be in fluid communication with the lumens  4066   c ,  4066   d  of the sheath  4016 , with the lumens  4066   a ,  4066   b  of the housing, with the pressure regulation valve  4011 , and with the inflation port  4060 . The stopcock  4064  of the inflation port can selectively be opened and closed to selectively establish and terminate, respectively, fluid communication between the connector  4063  and the balloon  4019 . 
     Accordingly, when the stopcock  4064  is open, a fluid delivery device (e.g., an air-filled syringe) coupled with the connector  4063  can urge fluid into the balloon  4019  to deploy the balloon  4019 . The fluid can fully deploy the balloon  4019 . Whether concurrently upon reaching the fully deployed state of the balloon  4019 , or whether at some point thereafter due to continued addition of fluid into the balloon  4019 , a pressure within the balloon  4019  can reach the threshold value. At this point, if attempts to pressurize the balloon  4019  above the threshold value, the pressure regulation valve  4011  will permit fluid to escape to the environment to maintain the balloon  4019  at the threshold value of pressure. Accordingly, the valve  4011  can maintain the balloon  4019  in the deployed state at a substantially constant pressure, despite attempts to further pressurize the balloon  4019  via the inflation or pressurization port  4060 . The stopcock  4064  can be closed to maintain the fluid within the sheath assembly  4002  and maintain the balloon  4019  in the deployed state. 
     The term “fluid” can refer herein to one or more gases, one or more liquids, or a combination thereof. For example, an inflation fluid used with the balloon  4019  can comprise one or more of air, nitrogen, water, saline solution, etc. In some embodiments, the fluid is air. 
     In the illustrated embodiment, the balloon  4019  includes a proximal sleeve or extension  4019   p  and a distal sleeve or extension  4019   d . The extensions  4019   p ,  4019   d  can be attached to the sheath  4016  in any suitable manner. For example, in some embodiments, the extensions  4019   p ,  4019   d  are bonded or otherwise secured to the sheath  4016  to form fluid tight seals at the proximal and distal ends of the balloon  4019 . 
     As previously discussed, in various embodiments, the balloon  4019  is semi-compliant or non-compliant. For example, the balloon  4019  may expand to a predetermined size via application of a first amount of pressure therein, and thereafter may either expand only minimally or not expand at all upon further addition of pressure therein. Stated otherwise, the balloon  4019  may define a preformed shape, such as the shape depicted in  FIG. 50 , to which it is inflated when deployed. 
     For example, with reference to  FIG. 45 , during manufacture, after the balloon  4019  has been secured to the sheath  4016 , the balloon  4019  may be deflated (e.g., via application of a vacuum at the inflation port  4060 ) or otherwise transitioned to a compressed, deflated, retracted, undeployed, wrapped, folded, or packaged state, as shown. A protective sleeve  4098  or other suitable cover may be placed over the balloon  4019  for packaging. When the sheath assembly  4002  is ready for use, the protective sleeve  4098  can be removed and the balloon  4019  can be advanced to the desired position within the esophagus. The balloon  4019  may maintain its low-profile configuration throughout insertion, such as may result from having been contained within the protective sleeve  4098  for an extended period. 
     The balloon  4019  can then be inflated into contact with the esophagus, in manners such as previously discussed. Throughout the inflation, the balloon  4019  may undergo little or no stretching. Rather, the balloon  4019  may be flexible so as to be compacted or compressed into its pre-use state, and then can be inflated to its preformed shape without, or substantially without, stretching the material of which the balloon  4019  is formed. Any suitable material is contemplated for the balloon  4019 . For example, in some embodiments, the balloon  4019  comprises a thermoplastic polyurethane elastomer, such as PELL E  THANE®, which is available from Lubrizol. In particular, in some embodiments, the balloon  4019  comprises PELL E  THANE® having a Shore A hardness 90. Other materials are also contemplated. In some embodiments, the balloon  4019  may be more compliant and may be configured to stretch into a desired shape when a predetermined pressure is applied therein. 
     With reference again to  FIG. 46 , the balloon  4019  can define any suitable shape and configuration. As with other embodiments disclosed herein, the illustrated balloon  4019  is substantially cylindrical with curved edges. The balloon  4019  defines a length L B  and a width W B , which may also be referred to as the diameter of the balloon  4019 . In the illustrated embodiment, the length L B  is greater than the width W B . In various embodiments, the length L B  is within a range of from about 1 to about 5 centimeters, from about 2 to about 4 centimeters, or from about 2.5 to about 3.5 centimeters; is no less than about 2, 2.5, 3, 3.5, 4, 4.5 or 5 centimeters; is no greater than about 2, 2.5, 3, 3.5, 4, 4.5, or 5 centimeters; or is about 2, 2.5, 3, 3.5, 4, 4.5, or 5 centimeters. In other or further embodiments, the width W B  is within a range of from about 1.5 to about 3.5 centimeters or from about 2 to about 3 centimeters; is no less than about 1.5, 2, 2.5, 3, or 3.5 centimeters; is no greater than 1.5, 2, 2.5, 3, or 3.5 centimeters; or is about 1.5, 2, 2.5, 3, or 3.5 centimeters. For example, in the illustrated embodiment, the length L B  is 3 centimeters and the width W B  is 2.5 centimeters. 
     The sheath assembly  4002  can define a total length L T  between its proximal and distal tips, and can further define a working length L W , which may represent a portion of the sheath assembly  4002  that can generally be manipulated for insertion into a patient. The working length L W  may, in some embodiments, desirably be sufficiently long to permit the distal, atraumatic tip  4013  to be inserted sufficiently deep into the esophagus of any of a variety of patients, including those having the largest anatomies, to be able to access a food impaction situated at or near the bottom of the esophagus. In various embodiments, the working length L W  is no less than about 50, 55, 60, 65, or 70 centimeters; is no greater than about 50, 55, 60, 65, or 70 centimeters; or is about 50, 55, 60, 65, or 70 centimeters. In the illustrated embodiment, the total length L T  is 64.5 centimeters and the working length L W  is 60 centimeters. 
     As previously discussed, a variety of sizes are contemplated for the sheath  4016 . In the illustrated embodiment, the sheath  4016  is 12 French. Similarly, a variety of sizes are contemplated for the instrument delivery lumen  4054  of the sheath  4016 . In the illustrated embodiment, the minimum inner diameter of the delivery lumen  4054  (e.g., along the horizontal dimension in  FIG. 49 ) is 0.133 inches. 
       FIG. 51  depicts a catheter assembly  4004  that can be well suited for use with the sheath assembly  4002 . Other embodiments of catheter assemblies disclosed herein are also possible. In the illustrated embodiment, the catheter assembly  4004  includes a catheter hub  4024  that is fixedly secured to a proximal end of a catheter  4026 , and is further connected to a proximal end of a strain relief sleeve  4025 . 
     The catheter hub  4024  includes a suction connector  4028  at a proximal end thereof. The suction connector  4028  can be a tapered suction fitting  4029  of any suitable variety, including those presently in use and suitable for connection to a variety of different sizes and constructions of vacuum line tubing. For example, the connector  4028  can be configured for slip fit connection to the vacuum system of a hospital via any suitable tubing. The hub  4024  can further include a handle  4040 , which may include grips  4041  for increased traction. The hub  4024  may define a distally projecting connector  4043 , similar to the connector  4058  of the sheath hub  4014  (see  FIG. 47 ), through which the catheter  4026  is inserted for connection to an interior of the hub  4014  and over which the strain relief sleeve  4025  is secured. 
     The various components of the catheter assembly  4004  can be formed of any suitable materials. In the illustrated embodiment, the hub  4024  comprises polycarbonate and the strain relief sleeve  4025  comprises a heat shrink polyolefin. 
     With reference to  FIG. 52 , the catheter  4026  can include a lubricious inner layer  4072  of any suitable variety. In the illustrated embodiment, the layer  4072  comprises a PTFE liner. The catheter  4026  can further include a body  4070  that includes a braided material and a polymeric material. In particular, the body  4070  includes a braided layer  4073  and an outer layer  4075  of polymeric material, which can extend into the braided layer  4073 . In the illustrated embodiment, the braided layer  4073  comprises a layer of braided  304  stainless steel, and the outer layer  4075  comprises nylon 12. The illustrated embodiment also includes a distal tip  4023 , which may include one or more different and/or additional materials from other portions of the catheter. For example, in the illustrated embodiment, the tip may be formed of or include polyethylene terephthalate (PET). Any other suitable composition of the catheter  4026  is contemplated. 
     Standard methods may be used to manufacture the catheter  4026 . For example, the catheter  4026  may be formed via a “stick build” in which the PTFE liner  4072  is placed over a mandrel, the stainless steel is braided over the PTFE liner  4072  to form the braided layer  4073 , a single-lumen extrusion of nylon 12 is slid over the braid, and then the materials are heated and reflowed. 
     With reference again to  FIG. 51 , the catheter  4026  can include a depth indicator  4027 , which can provide information regarding a position of the distal tip  4023  of the catheter  4026  within the sheath assembly  4002 . In the illustrated embodiment, the depth indicator  4027  comprises a transition line  4026 t between a proximal portion  4026   p  and a distal portion  4026   d  of the catheter  4026 . In some embodiments, the proximal and distal portions  4026   p ,  4026   d  of the catheter are different colors to provide a readily observable visual cue. For example, in one embodiment, the proximal portion  4026   p  is white and the distal portion  4026   d  is gray. Any other suitable indicium for the depth indicator  4027  is contemplated. For example, in other or further embodiments, the critical depth can be identified with a printed or laser marking. In the illustrated embodiment, the catheter  4026  can be formed in manners such as previously disclosed, but utilizing two different single-lumen extrusions of nylon 12 each having different colorants. The extrusions can be situated end-to-end over the braided layer  4073  prior to reflowing. 
     The distal portion  4026   d  of the catheter  4026  may define a retraction length L R  that is slightly shorter than the total length L T  of the sheath assembly  4002  (see  FIG. 46 ). In this manner, a practitioner may have a visual cue that the distal tip  4023  of the catheter  4026  is safely withdrawn within an interior of the sheath  4016  when, for example, a proximal end of the gray distal portion  4026   d  of the catheter  4026  is visible outside of the proximal end of the sheath assembly  4002 . It can be desirable for the distal tip  4023  to be within the sheath  4016  prior to insertion or repositioning of the system  4000  into or within the patient to ensure that the atraumatic tip  4013  of the sheath  4016  is the leading tip of the system  4000 , rather than the sharper coring tip  4023  of the catheter  4026 . In various embodiments, the retraction length L R  is shorter than the total length L T  of the sheath assembly  4002  by no less than about 0.4, 0.5, 0.6, 0.7, 0.8 centimeters. For example, in the illustrated embodiment, the retraction length L R  is shorter than the total length L T  of the sheath assembly  4002  by about 0.6 centimeters. In some instances, such an arrangement can ensure that the distal tip  4023  of the catheter  4026  is safely stowed in the sheath  4016  (e.g., is proximally recessed relative to the distal tip of the sheath  4016 ), while permitting the catheter  4026  to support (e.g., inhibit the kinking or other undesired deformation of) nearly an entire length of the sheath  4016 . 
     Similarly, the proximal portion  4026   p  of the catheter  4026  and the strain relief sleeve  4025  can define an exposed length L E  of which an entirety should be visible beyond the proximal end of the sheath assembly  4002  to ensure that the distal tip  4023  of the catheter  4026  is safely retracted within the sheath  4016 . The exposed length L E  at the proximal end of the catheter  4026  can be slightly longer than an exposable length of the distal end of the catheter  4026  that is permitted to extend past the distal tip  4013  of the sheath  4016  during coring and suctioning. In particular, in some embodiments, the exposed length L E  at the proximal end of the catheter  4026  is longer than the exposable length at the distal end of the catheter  4026  by the same distance to which the distal tip  4023  of the catheter  4026  is retracted from the distal tip  4013  of the sheath  4016  when the interface of the proximal and distal portions  4026   p ,  4026   d  of the catheter  4026  is flush with the proximal tip of the sheath assembly  4002 . 
     As discussed elsewhere herein, in some instances, it can be desirable for the exposable length at the distal end of the catheter  4026  to be relatively short to ensure that the distal tip  4013  of the catheter does not inadvertently come into contact with the esophagus. For example, in various embodiments, the exposable length may be no greater than 0.75, 1.0, 1.25, 1.5, or 2.0 inches. In some embodiments, such as illustrated, the exposed length L E  can include at least a portion of a length of the strain relief sleeve  4025 . In other embodiments, a proximal end of the exposed length L E  terminates substantially at a proximal end of a portion of the catheter  4026  that is not covered by the strain relief sleeve  4025 . 
     As with other embodiments disclosed herein, the catheter assembly  4004  can include a stopping region  4047 , which can interact with the sheath hub  4014  to delimit an amount of distal movement of the catheter  4026  beyond the distal tip  4013  of the sheath  4016 . In the illustrated embodiment, the stopping region  4047  is the diametrically or laterally expanded region defined by the connector  4043  portion of the catheter hub  4024  and the expanded portion of the strain relief sleeve  4025  that is connected thereto. The stopping region  4047  can interfere with a proximal end of the connector  4055  or may enter into and interfere with a proximal portion of the guide  4052  within the connector  4055 , each of which is defined by the housing  4050  (see  FIG. 47 ), as the catheter assembly  4004  is advanced distally through the sheath assembly  4002 . 
     The catheter assembly can define a total length L T  and a working length L W . In the illustrated embodiment, which is merely one illustrative example, the total length L T  is 77.5±1 centimeters and the working length L W  is 72.8±1 centimeters. The exposed length L E  is 8.9±0.05 centimeters. Other dimensions are possible and are contemplated by the present disclosure. 
     With reference to  FIG. 53 , an outer diameter OD of the illustrated catheter  4026  is 0.124±0.005 inches and an inner diameter ID of the catheter  4026  is 0.105±0.005 inches. The outer diameter OD may also be referred to as a maximum diameter of the catheter  4026 . A height H BEV  of the bevel at the distal tip  4023  is 0.025±0.005 inches. An angle a defined by the bevel, relative to an axial or longitudinal dimension of the catheter  4026 , is 20.0±0.05 degrees. Other dimensions are possible and are contemplated by the present disclosure. For example, the angle a can be greater than or less than that of the illustrated embodiment. In various embodiments, the angle a is no greater than 15, 20, 25, 30, or 35 degrees. The other dimensions may similarly be altered in other emboidments. 
       FIG. 54  depicts the spacer  4080  in greater detail. As previously discussed, the spacer  4080  is configured to maintain a predetermined relative position of the sheath assembly  4002  and the catheter assembly  4004  during insertion and/or manipulation of the system  4000  in the patient, such as during introduction of the system  4000  into the esophagus and into contact with an impacted food bolus. In particular, the spacer  4080  can be configured to maintain a relative orientation in which the distal tip  4023  of the catheter  4013  is retracted within the instrument delivery lumen  4054  of the sheath  4016 , or stated otherwise, is retracted relative to the distal tip  4013  of the sheath  4016 . 
     The illustrated spacer  4080  is an elongated clip  4082  that includes a proximal fastener  4086  and a distal fastener  4088 . The proximal fastener  4086  is configured to selectively attach to and detach from the connector  4043  portion of the catheter hub  4024  (see  FIGS. 45 and 51 ). The distal fastener  4088  is configured to selectively attach to and detach from the connector  4055  portion of the sheath hub  4014  (see  FIGS. 45 and 47 ). The fasteners  4086 ,  4088  can be of any suitable variety. In the illustrated embodiment, the fasteners  4086 ,  4088  are spring clips with resiliently flexible arms. 
     In some embodiments, the spacer  4080  is attached to the system  4000  during manufacture and packaging of the system  4000 . Accordingly, when a user removes the system  4000  from the packaging, the spacer  4080  may already be in place. In other embodiments, the spacer  4080  may come separately within the packaging, and instructions for use can indicate that the user can attach the spacer  4080  to the assemblies  4002 ,  4004  prior to insertion of the system  4000  into the esophagus of the patient. 
     In some embodiments, such as the illustrated embodiment, the spacer  4080  can be configured to be selectively detached from the assemblies  4002 ,  4004  and selectively reattached to the assemblies  4002 ,  4004 . For example, in some instances, a user may deploy the positioning element  4018  into contact with the esophageal wall and core through a portion of the blockage using the catheter assembly  4004 , such as by moving the catheter assembly  4004  longitudinally back and forth relative to the sheath assembly  4002 , which sheath assembly  4002  remains in a substantially fixed orientation relative to the esophagus and the blockage (e.g., food impaction) during thie initial phase of coring. 
     In some instances, after the initial coring, the user may wish to advance the sheath assembly  4002  to a more distal position within the esophagus, such as to be able to core deeper into the blockage. Accordingly, a user may wish to contract the positioning element  4018  (e.g., deflate the balloon  4019 ) or otherwise transition the positioning element  4018  to a lower profile and then move the system within the esophagus. In some instances, in order to protect the esophagus from inadvertent contact with the esophageal wall, it may be desirable for a user to reattach the spacer  4080  to the specified attachment regions of the assemblies  4002 ,  4004  to reestablish the fixed longitudinal relationship between the assemblies the ensures the distal tip of the catheter  4026  is retracted within the lumen of the sheath  4016 . Thus, in some instances, instructions for use may recommend or require that a user reattach the spacer  4080  prior to any movement within the esophagus when the positioning element  4018  is in the contracted state. 
     As a further example, the spacer  4080  can be reattached prior to removal of the system  4000  from the esophagus. In other instances, a user may not use the spacer  4080  during retraction. In certain of such instances, the user may fully retract the catheter assembly  4004  from the sheath assembly  4002  (e.g., pull proximally out of the sheath assembly  4002 ), may then subsequently contract the positioning element  4018  to a low profile, and then may remove the sheath assembly  4002  from the esophagus. 
     The system  4000  may be used in any of the manners disclosed herein, as suitable. For example, the various methods and/or portions (e.g., a subset of steps) thereof discussed with respect to, e.g., the systems  200 ,  3000 ,  3200  can be performed with the system  4000 . 
     With reference to  FIG. 55 , any of the systems or components thereof described herein may be provided in a kit  5000 . In some embodiments, the kit  5000  is particularly well suited for use in an emergency room setting. The kit  5000  may be used in blind procedures, such as those in which no direct or indirect visualization of the blockage is performed during the procedure. Accordingly, in some instances, the kit  5000  may be used by practitioners who are not specialized endoscopists, etc. 
     In the illustrated embodiment, the kit  5000  includes an embodiment of the system  4000 . The kit  5000  can further include instructions  5002  for using the embodiment of the system  4000 . For example, the instructions for use  5002  may provide directions with respect to any of the methods or processes disclosed herein. By way of further example, the instructions for use  5002  may recite any method and/or other portion of the present disclosure. 
     The kit  5000  can further include packaging  5004 . The system  4000  can be contained within the packaging  5004 , and the instructions  5002  can be contained within, printed on, or otherwise made accessible via the packaging  5004 . 
     In various embodiments, the kit  5000 —and, in particular, the system  4000  and the instructions for use  5002  thereof—can be approved of or authorized by a regulating body of a particular jurisdiction. For example, the kit  5000 , and the instructions  5002  for use thereof, may be approved of or authorized by the Food and Drug Administration of the United States of America and/or may comply with the regulations of other jurisdictions, such as by qualifying for CE marking in the European Union. 
     The instructions  5002  can provide directions with respect to any of the methods or processes disclosed herein. That is, the instructions  5002  can provide directions for using the system  4000 , or components thereof, in accordance with any of the methods or processes disclosed herein. One illustrative example of a set of instructions  5002  for use with one embodiment of the system  4000  is provided below. Other instructions may include more, fewer, and/or different directions than those provided in the illustrative example, and other embodiments of the system  4000  may include more, fewer, and/or different features than those discussed in the instructions. 
     EXAMPLE 1 
     An embodiment of the system  4000  is designed to core and aspirate food impactions. It is comprised of the sheath assembly  4002  and the catheter assembly  4004 . The sheath assembly  4002  is a 12 Fr OD with a 0.133″ ID, 62 cm in usable length, has a soft, atraumatic tip. It is designed to connect to a standard 10 cc-20 cc syringe for inflation of the balloon  4019 . The sheath assembly  4002  uses the low-pressure balloon  4019  to stabilize and center the aspiration catheter  4026  in the esophagus. 
     The catheter assembly  4004  is used through the working channel  4054  ( FIG. 49 ) of the sheath assembly  4002 . The catheter assembly  4004  has a molded tapered handle that is a slip fit connection to the vacuum system in the emergency room of a hospital. It has a beveled distal tip to aid in coring through food impactions. The catheter assembly  4004  extends approximately 2.00″ outside the tip of the sheath assembly  4002  during full insertion. In this example, the proximal portion  4026   p  of the catheter  4026  is colored white, and the distal portion  4026   d  is colored gray (see  FIG. 51 ). 
     The system  4000  can be packaged with instructions for use  5002 , which instructions may recite some or all of the following directions. The instructions detail illustrative examples of using the system  4000 . 
     The system  4000  is indicated for removal of food blockage and impaction in the esophagus. The system  4000  may desirably be used by a health care professional with adequate training in the use of the device. The catheter assembly  4004  moves freely through the sheath assembly  4002 . Do not remove system  4000  assembly clip  4082  until the sheath assembly  4002  is in final position within the esophagus, which may also be referred to as an anchored position in which the balloon  4019  is fully deployed. Do not use if the system  4000  cannot be advanced to at least 25 cm past the incisors as indicated by the relevant markings. 
     When repositioning or withdrawing the system  4000 , always withdraw the catheter assembly  4004  until the white proximal portion  4026   p  of the catheter  4026  is visible outside the sheath. This will ensure the atraumatic tip of the sheath assembly  4002  is always the leading edge during positioning. 
     Open the package and carefully remove balloon protector sleeve  4098  from the sheath assembly  4002 . Verify that the distal tip of the aspiration catheter is contained within the sheath and does not extend beyond the tip of the sheath. 
     Introduce the system  4000 , into the mouth and then advance beyond the cricopharyngeus into the esophagus. 
     Advance the system  4000  at least 25 cm from the incisors. Verify the depth by the marking on the external surface of the sheath. Insertion of the system  4000  to a depth of less than 25 cm from the incisors could lead to inadvertent balloon inflation within the pharynx. 
     Advance the system  4000  to the level of the food impaction as indicated by resistance to further passage of the system  4000 . 
     Withdraw the system  4000  approximately 1-2 cm (e.g., a short distance) from the point of contact of the food impaction. This will allow proper positioning, (i.e., centering) and inflation of the balloon. 
     Inflate the balloon to its full diameter by attaching a standard 10 cc or 20 cc syringe to the luer lock inflation port and injecting 20 cc&#39;s of air into the balloon. Once balloon has been inflated close the stopcock  4064  to seal air within the system. Gently pull on the balloon sheath to confirm the balloon is fully inflated and secured within the esophagus. 
     Remove the assembly clip  4082  from the system  4000 . This will allow free movement of the catheter assembly  4004  relative to the anchored sheath assembly  4002 . 
     Attach standard suction tubing of a suction system to the catheter assembly  4004  handle by pressing tubing firmly onto the handle. Attach the suction system to the wall suction of the hospital in any suitable manner. For example, press fit tubing of the suction system over a wall-mounted nozzle in a hospital room that is connected to the hospital suction source. 
     Turn on the wall suction. Adjust wall suction to its highest power setting. 
     The aspiration catheter, attached to suction, will then be employed to core pieces of the food impaction and suction the pieces as cored. The aspiration catheter will be advanced into the food to core pieces of food and then be withdrawn to allow suction. This process will be repetitively performed (coring and suctioning) as needed to clear the impaction. Repeat this action until food impaction is clear. The food impaction may naturally pass into the stomach once a sufficient portion thereof has been cored away. 
     If necessary or desired, the sheath balloon can be deflated by opening the stopcock and pulling a vacuum on the inflation syringe and re-inflated in order to advance, withdraw or reposition the sheath to optimize clearance of the impaction. 
     The aspiration catheter should be safely withdrawn into the sheath, and the balloon can be partially or completely deflated to allow free motion of the sheath, to allow advancement of the sheath into any remaining impaction to push any remaining food distally into the stomach. Advancement of the sheath should not be attempted until the aspiration catheter is contained within the confines of the sheath (e.g., the gray distal portion  4026   d  of the aspiration catheter  4026  is visible outside of sheath assembly  4002 ). 
     After the food impaction is cleared, withdraw the catheter assembly  4004  until the gray distal portion  4026   d  is visible outside the sheath assembly  4002 , open the stopcock and completely deflate the balloon by pulling a vacuum on the inflation syringe. 
     Withdraw the system  4000  from the esophagus. 
     With reference again to  FIGS. 51 and 53 , in some embodiments, the catheter assembly  4004  is particularly well suited for use with any of a variety of standard or otherwise commercially available endoscopes. In some embodiments, the catheter assembly  4004  may be better suited for use with such endoscopes than with certain embodiments of dedicated sheaths. For example, the catheter assemblies can be deployed through a standard working channel of an endoscope. In certain of such instances, the food bolus and progress of the procedure can be visually monitored via the endoscope by a professional during certain uses of the catheter assemblies. 
     In some instances, the catheter assembly  4004  for use with an endoscope may vary from certain embodiments configured for use with a sheath assembly  4002 . For example, in some instances, the catheter assembly  4004  may be devoid of a depth indicator  4027 . By way of further example, rather than having differently colored proximal and distal portions  4026   p ,  4026   d , the shaft of the catheter  4026  may be a uniform color along a full length thereof. 
     In some embodiments, various dimensions of the catheter assembly  4004  can be optimized for use with endoscopes. In some illustrative examples, the total length L T  of the catheter assembly  4004  may be relatively longer, whereas the outer diameter OD and the inner diameter ID are smaller. For example, in one illustrative example, the total length L T  is 128.7±1 centimeters, the outer diameter OD is 0.107±0.005 inches and the inner diameter ID is 0.096±0.005 inches. The remaining dimensions (e.g., the bevel angle and bevel height) may be as previously identified. Other values of the various dimensions are possible and are contemplated by the present disclosure. 
     With reference to  FIG. 56 , any of the catheter assemblies disclosed herein may be provided in a kit  6000 . In certain embodiments, the kit  6000  is particularly well suited for use with a standard or otherwise commercially available endoscope. For example, the kit  6000  may be used by an endoscopist or other similarly trained practitioner. In the illustrated embodiment, the kit  6000  includes an embodiment of the catheter assembly  4004 . The kit  6000  can further include instructions  6002  for using the embodiment of the catheter assembly  4004 . In particular, the instructions  6002  can provide directions to carry out any procedure, procedural step, or other action disclosed herein. By way of further example, the instructions for use  6002  may recite any method and/or other portion of the present disclosure 
     The kit  6000  can further include packaging  6004 . The catheter assembly  4004  can be contained within the packaging  6004 , and the instructions  6002  can be contained within, printed on, or otherwise made accessible via the packaging  6004 . 
     In various embodiments, the kit  6000 —and, in particular, the catheter assembly  4004  and the instructions for use  6002  thereof—can be approved of or authorized by a regulating body of a particular jurisdiction. For example, the kit  6000 , and the instructions for use  6002  thereof, may be approved of or authorized by the Food and Drug Administration of the United States of America and/or may comply with the regulations of other jurisdictions, such as by qualifying for CE marking in the European Union. 
     The instructions  6002  can provide directions with respect to any of the methods or processes disclosed herein. That is, the instructions  6002  can provide directions for using the catheter assembly  4004  in accordance with any of the methods or processes disclosed above. One illustrative example of a set of instructions  6002  for use with one embodiment of the catheter assembly  4004  is provided below. Other instructions may include more, fewer, and/or different directions than those provided in the illustrative example, and other embodiments of the catheter assembly  4004  may include more, fewer, and/or different features than those discussed in the instructions. 
     EXAMPLE 2 
     The catheter assembly  4004  is designed to be used in the esophagus to remove food blockages. It is an 8 Fr OD with a 0.090 inch max ID, 124 cm useable length, single-lumen, braided biocompatible catheter with a sharp distal tip for cutting through the food impaction. The catheter assembly  4004  has a molded, tapered handle that is a slip fit connection to the vacuum system in the hospital. 
     The catheter assembly  4004  is designed to be used through the working channel (&gt;2.7 mm ID) of a standard endoscope. It is designed to connect to extend outside the distal end of an endoscope by approximately 1 inch when fully inserted. 
     The catheter assembly  4004  can be packaged with instructions for use  6002 , which instructions may recite some or all of the following directions. The instructions detail illustrative examples of using the catheter assembly  4004 . 
     The catheter assembly  4004  is indicated for removal of food blockage/impaction in the esophagus. 
     The catheter assembly  4004  should be used by a health care professional with adequate training in the use of the device. 
     Do not use if the device is kinked or damaged in any way. 
     Do not use if the catheter assembly  4004  does not move freely through the working channel of a standard endoscope with a working channel ID of 2.7 mm or greater. 
     Following standard practices, introduce a standard endoscope (e.g., through the mount of the patient) to the level of the food impaction. 
     Insert the catheter assembly  4004  through the working channel of the endoscope until the aspiration catheter is visible through the distal end of the endoscope. 
     Once positioned in the endoscope, attach standard suction tubing to the catheter handle by pressing tubing firmly onto the handle. Attach the suction system to the wall suction of the hospital in any suitable manner. For example, press fit tubing of the suction system over a wall-mounted nozzle in a hospital room that is connected to the hospital suction source. 
     Deliver a plurality of (e.g., 4 to 5) drops of water through the irrigation lumen of the endoscope. This will help saturate the food impaction making it easier to aspirate. 
     The aspiration catheter, attached to suction, will then be employed to core pieces of the food impaction and suction the pieces as cored. The aspiration catheter will be advanced into the food to core pieces of food and then be withdrawn to allow suction. This process will be repetitively performed (coring and suctioning) as needed to clear the impaction. Repeat this step until food impaction is clear (e.g., until food impaction is naturally passed out of the esophagus and into the stomach by the patient). 
     When the impaction has been cleared, detach the vacuum from catheter handle and remove the catheter assembly  4004  from the endoscope. 
       FIGS. 57A and 57B  depict another embodiment of a sheath assembly  7002  in an undeployed state and in a deployed state, respectively. The sheath assembly  7002  can be used with embodiments of catheter assemblies disclosed herein in manners such as are also disclosed herein. 
     The sheath assembly  7002  can function similarly to other sheath assemblies disclosed herein. In general, the sheath assembly  7002  includes a positioning element  7018  and an actuator  7060  via which the positioning element  7018  can be deployed and retracted. 
     As with other embodiments disclosed herein, the sheath assembly  7002  includes hub  7014  that is coupled with a sheath  7016  in any suitable manner. The sheath  7016  defines an instrument deployment lumen  7054  within which a catheter can be positioned, and through which the catheter can be advanced and/or retracted. The sheath  7016  can further define an actuation channel or lumen  7066 , which can resemble the inflation channels or lumens  3066 ,  3266 ,  4066  described above. All such lumens can allow movement therethrough of an actuation element (such as fluid or, as discussed further hereafter for the present case, an actuation wire or rod) to effect actuation or retraction of a positioning element. 
     In the illustrated embodiment, the positioning element  7018  comprises an expandable member  7019  of any suitable variety. The expandable member  7019  can, for example, comprise a braided or other configuration of wires or other materials that can be selectively expanded to a larger profile configuration or retracted to a lower profile configuration. For example, the expandable member  7019  can resemble or be formed as a selectively expandable and retractable stent, such as, for example, a braided stent. 
     With reference to  FIGS. 58A and 58B , in other instances, rather than defining a braided sleeve, an expandable member, or positioning element, can define a series of longitudinally extending wires or other elongated elements that are predisposed to flare outwardly when compressed and can assume a low-profile configuration when placed under tension. In still other embodiments, an expandable member, or positioning element, can define a plurality of resilient arms (e.g.,  FIGS. 59A and 59B ) configured to press outwardly into contact with the esophagus. Any other suitable system for expanding into contact with the esophagus and retracting away from contact with the esophagus is contemplated. 
     In various embodiments, the expandable member  7019  is resiliently flexible and/or comprises a shape-memory material. In various embodiments, the expandable member  7019  may be biased toward a retracted orientation ( FIG. 57A ), such that the bias must be overcome to deploy the expandable member  7019 . The expandable member  7019  may readily return to the retracted orientation under influence of the bias, when so permitted. In other embodiments, the expandable member  7019  may be biased toward the deployed orientation ( FIG. 57B ), such that actuation of the expandable member  7019  includes permitting the bias to naturally deploy the expandable member  7019 . The expandable member  7019  may be returned to the retracted orientation by overcoming the bias. In other embodiments, the expandable member  7019  is not subject to internal or other biases when positioned in either of the retracted or deployed orientations. 
     A distal end of the expandable member  7019  can be fixed relative to the sheath  7016 . A proximal end of the expandable member  7019  can be movable relative to the sheath  7016 . For example, the proximal end of the expandable member  7019  can be permitted to translate longitudinally relative to the sheath  7016 . 
     The proximal end of the expandable member  7019  can be coupled with a mechanical linkage  7091  of any suitable variety, such as a wire or rod  7093 . The mechanical linkage  7091  can further be coupled with an actuation interface  7095  of any suitable variety, such as a button, lever, switch, slider, etc. The actuation interface  7095  can move the mechanical linkage  7091  so as to effect actuation and retraction of the expandable member  7019 . Accordingly, the actuator  7060  can be communicatively coupled with the positioning element  7018 . In particular, the actuation interface  7095  is configured to directly, mechanically communicate with the expandable member  7019  via the mechanical linkage  7091 . 
     For example, in the illustrated embodiment, the actuation interface  7095  comprises a switch that is translatable relative to the housing  7014 . By urging the switch distally from the proximal position shown in  FIG. 57A  to the distal position shown in  FIG. 57B , the mechanical linkage  7091  is likewise urged distally, which likewise urges the proximal end of the expandable member  7019  distally. Due to the fixed relationship of the distal end of the expandable member  7019  relative to the sheath  7016 , the expandable member  7019  can deploy outwardly to the configuration depicted in  FIG. 57B . Similarly, urging the switch proximally from the distal position shown in  FIG. 57A  to the proximal position shown in  FIG. 57B  can return the expandable member to the retracted orientation shown in  FIG. 57A . 
       FIGS. 58A and 58B  depict another embodiment of a sheath assembly  8002  in an undeployed state and in a deployed state, respectively. The sheath assembly  8002  can closely resemble the sheath assembly  7002  just described, but may include a different expandable member  8019  that includes a plurality of longitudinally extending wires or elongated elements  8095 . The expandable member  8019  can perform substantially as previously described with respect to the expandable member  7019 . 
       FIGS. 59A and 59B  depict another embodiment of a sheath assembly  9002  in an undeployed state and in a deployed state, respectively. The sheath assembly  9002  can closely resemble the sheath assemblies  7002 ,  8002  just described, but may include a different expandable member  9019  that includes a plurality of resiliently expandable arms  9097 . In the illustrated embodiment, the arms  9097  are configured to rotate outward into contact with the esophageal wall when deployed. In particular, in the illustrated embodiment, the arms  9097  are deployed when proximal portions thereof are advanced distally so as to no longer be restrained in a low-profile orientation by a retainer element  9099 . 
     Although various embodiments are described herein, the embodiments are only examples and should not be construed as limiting. The examples described above generally refer to food impactions in the esophagus. However, many other similar impactions can be addressed using the systems and methods described herein. For example, embodiments of the systems may be used with any suitable anatomical tube (e.g., the esophagus, a bronchus, a vessel). 
     For example, a person can choke while eating, and food can get aspirated and lodge in the trachea, or can also lodge in the lung, specifically any portion of the bronchial tree. Mucus can also become trapped anywhere in the bronchial tree, causing mucus plugging. When this occurs, one or more of the embodiments described herein can be used to core and suction said food or mucus, such as by placing the device, for example, through the working channel of a flexible or rigid bronchoscope as opposed to an endoscope. 
     One or more of the embodiments described herein can also be used to core, suction and remove trapped blood or blood clots anywhere in the GI tract, specifically the esophagus, stomach, small intestine or large intestine. 
     One or more of the embodiments described herein can also be used to core, suction and remove trapped food, blood or blood clots, or mucus or mucus plugs, anywhere in the pulmonary organ system, i.e., the trachea or lung i.e. anywhere in the bronchial tree. 
     One or more of the embodiments described herein can be used to core and remove blood or blood clots, or atheroma or atheromatous plaque anywhere in the vasculature system, i.e. great arteries or veins, or peripheral vasculature i.e. the peripheral arteries or veins. To core harder materials such as calcified plaque, a stainless steel tip can be attached to the end of the suction catheter. 
     One or more of the embodiments described herein can also be used to core and remove blood or blood clots, or atheroma or atheromatous plaque anywhere in the heart or coronary arteries. To core harder materials such as calcified plaque, a stainless steel tip can be attached to the end of the suction catheter. 
     In another example, one or more of the embodiments described herein can be used to core and suction kidney stones from the urinary system, specifically the ureters, bladder and kidneys. To core harder materials such as calcified, struvite, oxalate or uric acid kidney stones a stainless steel tip can be attached to the end of the suction catheter. 
     In yet another example, one or more of the embodiments described herein can be used to core and remove gallstones or tumors lodged in the biliary tree (common bile duct or peripheral ducts). Harder materials can be cored by attaching a stainless steel tip to the end of the suction catheter. 
     For example, in some embodiments, an endoscope  210  of any suitable variety, such as a duodenoscope, is inserted into and advanced through the upper gastrointestinal tract of a patient. The duodenoscope can be advanced through the mouth, esophagus, and stomach and into the duodenum. A distal end of the duodenoscope can be brought to the level of, or stated otherwise, can be positioned near (e.g., adjacent to), the major duodenal papilla. 
     In various embodiments, a device is advanced through the working channel of the duodenoscope to assist in positioning a catheter assembly (e.g., an embodiment of the catheter assembly  4004 ) within the biliary tree to core and remove the undesired material, such as a gallstone or tumor. For example, in some embodiments, a guidewire is advanced through the working channel of the duodenoscope and, while the distal end of the duodenoscope remains positioned adjacent to the major duodenal papilla, the guidewire can be advanced out of a distal end of the working channel, through the major duodenal papilla, then through the common bile duct or the pancreatic duct to a location of the gallstone, tumor, or any other undesired material. For example, a distal end of the guidewire may be placed just proximal to the gallstone or tumor, in contact with the gallstone or tumor, or may be advanced by or through the gallstone or tumor so as to extend distally beyond (from the perspective of the practitioner) the undesired material. Any suitable imaging technique may be used in delivering the guidewire to the desired locations, such as, e.g., fluoroscopy. 
     With the guidewire in place, the catheter assembly may subsequently be advanced through the working channel of the duodenoscope and over the guidewire. The catheter assembly may further be advanced out of the duodenoscope over the guidewire and into proximity to the gallstone or tumor. In some instances, the guidewire may then be removed. Suction and coring of the undesired material may take place in manners such as previously described. 
     In some instances, different apparatus and/or techniques may be used to achieve the desired positioning of the guidewire and/or the catheter assembly. For example, in some instances, any suitable cholangioscopy procedure (e.g., endoscopic retrograde cholangiopancreatography) may be employed to position an embodiment of the catheter assembly  4004  for coring and removal of, e.g., a gallstone, tumor, blood clot, or other lesion or material. In some instances, an imaging probe of any suitable variety may be used in conjunction with or instead of fluoroscopic imaging. Any suitable imaging probe is contemplated. For example, in some instances, a direct-visualization probe of any suitable variety may be used. By way of illustration, and without limitation, the SpyGlass® Direct Visualization System, available from Boston Scientific, may be used. The imaging probe, such as, for example, the SpyScope® Access and Delivery Catheter, can be inserted through the working channel of the duodenoscope and out of the distal end of the duodenoscope, through the major duodenal papilla, and can be controlled (e.g., via proximally located actuators of the probe) so as to advance through the biliary tree to a desired position. For example, the desired position may place the distal end of the probe at a position just proximal to (from the perspective of the practitioner) the gallstone or tumor. 
     In some instances, a guidewire may then be advanced through a working channel of the imaging probe. As with other procedures previously described, the distal end of the guidewire may be placed just proximal to the gallstone or tumor (or other material), in contact with the gallstone or tumor, or may be advanced by or through the gallstone or tumor so as to extend distally beyond (from the perspective of the practitioner) the undesired material. In some instances, the imaging probe is removed proximally over the guidewire. The catheter assembly may then be advanced over the guidewire and into contact with the undesired material for coring and removal. In some instances, the guidewire is removed prior to coring and suctioning. 
     In other instances, the imaging probe may be used without a guidewire. For example, once the imaging probe has been advanced through the duodenoscope and is in place, the catheter assembly may be advanced through a working channel of the imaging probe and into contact with the gallstone or tumor. Imaging (e.g., direct visualization) of the target site or working area may be maintained via the imaging probe as the catheter assembly is repeatedly advanced and retracted to core and/or suction away pieces of the undesired material. The imaging probe can provide continuous or substantially continuous viewing of the target region during the coring procedure. 
     In still other instances, the catheter assembly (e.g., an embodiment of the catheter assembly  4004 ) can be advanced through the working channel of the duodenoscope and into a desired position within the biliary tree without assistance from additional devices deployed through the endoscope, such as a guidewire or a separate imaging probe. 
     As can be appreciated from the foregoing, the catheter assembly (e.g., embodiments of the catheter assembly  4004 ) can be used to remove undesired material—such as gallstones, tumors, or other undesired material—from within, e.g., the pancreas. For example, the material may be removed from one or more ducts that pass through the pancreas. Various embodiments may be used to remove other types of undesired material from these and/or other regions of the pancreas and/or to remove undesired material from the pancreas in other manners, or stated otherwise, via other approaches or procedures. 
     In some procedures, an embodiment of a catheter assembly (e.g., an embodiment of the catheter assembly  4004 ) is used in an endoscopic transmural necrosectomy (ETN) procedure for the treatment of pancreatitis. Such a procedure may also be referred to as a direct endoscopic necrosectomy (DEN). Endoscopic transmural necrosectomy can be performed via the gastric lumen or the duodenal lumen and involves transmural puncture from the gastric or the duodenal lumen into a target region, such as a necrotic cavity, within the pancreas. 
     With reference to  FIGS. 60A and 61A , in various embodiments, any suitable endoscope  9100 , such as a gastroscope or a duodenoscope, is inserted through the mouth of a patient and advanced until positioned inside the stomach S ( FIG. 60A ) or the duodenum D ( FIG. 61A ) of the patient. In particular, the endoscope  9100  can be advanced until a distal end thereof is positioned near or in the vicinity of a target region  9102  of the pancreas P. The target region  9102  may be located on or within the pancreas. Stated otherwise, the distal end of the endoscope  9100  is brought into proximity to the target region  9102 , but is separated therefrom by at least the wall of the stomach S or the wall of the duodenum D, depending on the location of the target region  9102  within the pancreas. In some instances, the target region  9102  may be beneath an outer surface of the pancreas P, such that healthy pancreatic tissue is also positioned between the distal end of the endoscope  9100  and the target region  9102 . 
     The following discussion will first focus on procedures that involve a transmural puncture from the gastric lumen to the pancreas, with particular reference to  FIGS. 60A-60D . Such procedures may also be referred to as endoscopic transgastric necrosectomies. Similar procedures that instead involve transmural punctures into through the duodenal wall will subsequently be discussed with reference to  FIGS. 61A-61C . 
     With reference to  FIGS. 60A-60D , the target region  9102  can comprise any undesirable or problematic material  9104 . For example, in various embodiments, the undesirable material  9104  can comprise one or more collections (e.g., fluid or necrotic tissue) in the pancreatic parenchyma or peripancreatic tissue. Such collections may be caused by inflammation, and may include one or more of acute peripancreatic fluid collections, pancreatic pseudocysts, acute necrotic collections, and walled-off necrotic collections. Acute collections may typically remain sterile, and may resolve on their own. However, some collections can become pseodocysts, which may turn into walled-off necrotic collections. Pseudocysts are collections in peripancreatic tissue that mostly contain solid material. These can cause occlusion of the main pancreatic duct or branches. Walled-off necrotic collections consist of mature necrotic material (fluid and/or solid) that can be completely encapsulated and demarcated inside a thickened wall of tissue lacking an epithelial lining. Such can develop about four weeks after the onset of necrotizing pancreatitis. For endoscopic transmural necrosectomy procedures, the undesirable material  9104  typically includes necrotic material, such as the necrotic material in walled-off necrotic collections. Accordingly, hereafter the undesirable material  9104  may also be referred to as necrotic material  9104 , and the target region  9102  may also be referred to as a necrotic target  9102 . Despite these appellations for purposes of convenience, it should be understood that in some instances, the undesirable material  9104  may not be necrotic. For example, the undesirable material  9104  may be of a variety that may become necrotic or that may contribute to necrosis elsewhere. 
     With reference to  FIG. 60A  the target region  9102  may be identified via the endoscope  9100  (e.g., a gastroscope). For example, in some instances, the target region  9102  may give rise to a visible bulge of the gastric wall, which can be visually identified via an endoscope  9100  that includes a visual imaging system. In some instances, the endoscope  9100  may comprise a forward-viewing therapeutic gastroscope. In other or further instances, the endoscope  9100  may include ultrasonic imaging capabilities. For example, the endoscope  9100  can additionally or alternatively include an endoscopic ultrasound (EUS) system of any suitable variety. In some instances, such as when the endoscope  9100  is configured for EUS, the target region  9102  can be identified, even in the absence of a visual bulge. In some instances, EUS can advantageously help identify blood vessels that may desirably be avoided during puncture and expansion of a tract through the gastric wall to the target region  9102 . In various embodiments, fluoroscopic and/or ultrasonic (e.g., EUS) imaging may be used in positioning the endoscope  9100  and/or in subsequent stages of the procedure, such as forming a puncture site through the gastric wall. 
     After identification of the target region  9102 , a transmural puncture may be made through the gastric wall and to or into the pancreas. Any suitable technique is contemplated for the puncture. In various embodiments, any suitable needle or needle knife apparatus may be advanced through the working channel of the endoscope  9100  and advanced through the posterior gastric wall to form an opening therethrough. The cutting or puncturing apparatus can be advanced through the gastric wall and into the target region  9102 , such as into a necrotic cavity. The puncturing or cutting apparatus can fully perforate the stomach wall. 
     In some embodiments, a guidewire may be passed through the puncture site into the necrotic cavity, after which the perforating device may be removed. In some instances, it may be desirable for the guidewire to be inserted so as to have a relatively stable and straight (rectilinear) approach through the gastric wall and into the necrotic cavity. 
     The puncture tract through the gastric wall can then be dilated. In some instances, this can be accomplished by advancing a balloon catheter over the guide wire and expanding the balloon, in any suitable manner. The balloon catheter may have a relatively large balloon, which can ultimately facilitate passage of the distal end of the endoscope through the puncture tract. In some embodiments, stepwise dilatation may be performed. For example, in some instances the tract may be expanded from approximately 12 millimeters in diameter up to 15 millimeters. 
     In some instances, the balloon may be advanced distally through the tract, with the distal end of the endoscope  9100  trailing behind. Stated otherwise, the distal end of the endoscope  9100  may be passed through the tract into the target region  9102  (e.g., the necrotic cavity). In some instances, once the distal end of the endoscope  9100  is in place, the necrotic cavity can be insufflated. For example, in some instances, carbon dioxide may be passed through the endoscope into the necrotic cavity. The balloon may be deflated and removed through the endoscope  9100 . 
     In other or further embodiments, prior to the initial insertion of the endoscope  9100  through the tract, a large-diameter stent (e.g., metal or plastic stent) may be positioned within the tract and expanded to facilitate passage of the endoscope. In other instances, the stent may instead be placed in the tract after the endoscope has first been advanced through the tract (in manners such as previously disclosed), kept in place during removal of necrotic tissue, and subsequently removed from the tract. The stent may maintain a passage through which one or more subsequent endoscopic transgastric necrosectomies may be performed, thus permitting omission of many of the early steps of the initial necrosectomy (e.g., puncture, tract expansion) in subsequent procedures. Moreover, the stent may permit drainage into the stomach when not actively in use during a necrosectomy. In some instances, the stent may ultimately be removed or, in some instances, permitted to biodegrade/bioresorb in any suitable manner at the completion of all desired necrosectomies. 
       FIG. 60B  illustrates a stage of certain procedures in which the distal end of the endoscope  9100  has been advanced through the stomach wall and near or into a necrotic cavity. The balloon catheter has been removed from a working channel  9110  of the endoscope  9100 . Once the endoscope  9100  is in a desired position, a catheter assembly  9120 , which may also be referred to as a coring catheter  9120 , is advanced through the working channel  9110 . The coring catheter  9120  can resemble, as suitable for the present application, any of the catheter assemblies described elsewhere herein, such as, for example, the catheter assemblies  100 ,  900 ,  3004 ,  3604 ,  3704 ,  3804 ,  4004 . In some embodiments, a length of the coring catheter  9120  can be selected to ensure that the coring catheter  9120  can extend past a distal end of the endoscope  9100 , when the endoscope  9100  is positioned as previous described (e.g., with the distal tip thereof at or near the target region  9102 ). An outer diameter of the coring catheter  9120  can be sufficiently small to readily pass through the working channel  9110  of the endoscope  9100 . 
       FIG. 60C  illustrates a stage of certain procedures in which the coring catheter  9120  has been advanced past the distal end of the endoscope  9100  into the target region  9102 . In the illustrated embodiment, the coring catheter  9120  has been brought into contact with the necrotic material  9104 . The coring catheter  9120  can be used to debride the necrotic material  9104 . In particular, coring of the necrotic material  9104  can be achieved in manners such as previously described with respect to other unwanted materials. For example, the distal tip of the coring catheter  9120  can be advanced into the necrotic material  9104 . Suction can be applied at a proximal end of the coring catheter  9120  to suction cored pieces and/or to assist in coring the pieces and suctioning the cored pieces away from the target region  9102 . The coring catheter  9120  can also or alternatively suction blood and/or pancreatic fluids away from the target site. Visualization of at least a portion of the target region  9102  can be maintained by the endoscope  9100  during suctioning. Suctioning of the various material from the target site or field can leave this region clear for good visualization via the endoscope. 
     The coring catheter  9120  can suction multiple cores of necrotic material  9104  through a lumen  9122  thereof and away from the target region  9102 . In some instances, the coring catheter  9120  is advanced substantially in a straight line, and multiple cores are suctioned away as the catheter is advanced distally. In other or further instances, a back-and-forth motion may be used along the linear path to achieve coring and suctioning. For example, the coring catheter  9120  can be repeatedly advanced and retracted, or moved forward and backward (distally and proximally), to suction the cores. The coring catheter  9120  can be moved in any desired direction to remove as much of the necrotic material  9104  as desired, such as all or substantially all of the necrotic material  9104 . The endoscope  9100  can be repositioned as desired to direct the coring catheter  9120  along a path that will achieve the desired coring. For example, in some embodiments, the coring catheter  9120  can extend substantially rectilinearly from the working channel  9110 . The endoscope  9100  can be moved so as to permit the coring catheter  9120  to extend therefrom along a line that will bring the distal tip of the coring catheter  9120  into contact with a desired portion of the necrotic material  9104  for coring and removal. It can be desirable to debride the necrotic tissue until the cavity is lined with healthy granulation tissue. 
     In other instances, the coring catheter  9120  includes a pre-curved distal end, which may facilitate manipulation within the target. For example, as illustrated in  FIG. 66 , in some embodiments, the coring catheter  9120  can include a distal end that is curved to define an angle β relative to a central longitudinal axis A L  of the coring catheter  9120 . The preformed or natural bend or pre-curve can be formed in any suitable manner. The distal end of the coring catheter  9120  can be flexible such that the distal end may be retained within the working channel of the endoscope in a less curved shape, which may be substantially rectilinear or which may be closer to rectilinear than when in the pre-curved orientation. As the distal end is advanced out of the endoscope, the distal end of the catheter  9120  can naturally or automatically (e.g., resiliently) return to the pre-curved orientation. The pre-curved shape may, in some instances, facilitate reaching portions of the target region  9102  that might otherwise be difficult to reach by pointing the distal end of the endoscope toward the hard-to-reach area and advancing a rectilinear coring catheter thereat. In other or further instances, the pre-curved coring catheter can facilitate a procedure by permitting a certain orientation of the endoscope to remain substantially fixed (e.g., without manipulation of deflection controls at a distal end of the endoscope) while the coring catheter  9120  is advanced therefrom and positioned at various portions of the target region  9102 . In some instances, the user can rotate the coring catheter  9120  within the working channel of the endoscope to access multiple regions that are positioned off-axis relative to the distal end of the endoscope. The coring catheter  9120  thus may be advanced and/or retracted longitudinally relative to the endoscope and/or may be rotated relative to the endoscope to reach a larger volume of space than may otherwise be achieved by a substantially linear ended coring catheter, without deflection of the distal tip of the catheter. In some instances, similar advantages may be achieved in other contexts, such as in positioning the coring catheter  9120  into portions of a food impaction within the esophagus, advancing the coring catheter  9120  down branches of the bronchial or biliary trees, etc. 
     In various embodiments, the angle β may be no greater than 15, 30, 45, 60, 90, 180, or 270 degrees; may be no less than 15, 30, 45, 60, 90, 180, or 270 degrees; may be within a range of from about 15 to 30, 45, 60, 90, 180 or 270 degrees, from about  30  to  45 ,  60 ,  90 ,  180 , or  270  degrees, from about  45  to  60 ,  90 ,  180 , or  270  degrees, from about 60 to 90, 180, or 270 degrees, from about 90 to 180 or 270 degrees, or from about 180 to 270 degrees; or may be about 15, 30, 45, 60, 90, 180, or 270 degrees. 
     With reference again to  FIG. 60C , after debridement is complete, the coring catheter  9120  can be removed from the endoscope  9100 . In some instances, one or more nasocystic catheters may then be placed for drainage and lavage between necrosectomy sessions. In other instances, the stent may merely be left in place without any instruments positioned therein to permit drainage of necrotic material into the stomach. In other or further instances, multiple transmural stents may be placed (e.g., a multiple-gateway approach) to facilitate drainage during necrosectomy. 
     In some instances, aggressive lavage of the necrotic cavity may be used prior to or during the coring to facilitate the necrosectomy. For example, lavage may be achieved via a fluid delivery lumen of the endoscope  9100  before, during, and/or after the coring catheter  9120  is used for debridement of the necrotic material. Ultimately, the endoscope  9100  is removed from the patient. 
     With reference to  FIG. 60D , in some instances, a stent  9130  can be placed in the transmural tract to facilitate passage of the endoscope  9100 . In some instances, the stent  9130  is placed prior to the initial introduction of the endoscope  9100  through the stomach wall. In other instances, the stent  9130  is placed at the end of a procedure to maintain patency of the tract and provide a passageway for the endoscope  9100  for subsequent necrosectomies. Any suitable stent is contemplated. For example, in some embodiments, the stent  9130  comprises an AXIOS™ stent available from Boston Scientific.  FIG. 60D  depicts a stage of a procedure in which the endoscope  9100  passes through the stent  9130  and the coring catheter  9120  passes through the endoscope  9100  to debride the necrotic material  9104 . The debridement (e.g., coring and suctioning of cores) of the necrotic material  9104  can proceed in manners such as previously discussed. Upon completion of debridement, the coring catheter  9120  and the endoscope  9100  can be removed from the patient. The stent  9130  can be left in place for further debridement, in manners such as just discussed, at later times, e.g., over the course of days or weeks. 
       FIGS. 61A-61C  depict additional procedures similar to those of  FIGS. 60A-60C . In these procedures, the location of the target region  9102  is in the head of the pancreas P (rather than in the tail, as in  FIG. 60A ), and is accessible by forming a passageway through the duodenum D. In certain embodiments, the endoscope  9100  can be a duodenoscope. Embodiments of the coring catheter  9120  can be the same as or different from that used in the procedures of  FIGS. 60A-60C . For example, in some instances, the coring catheter  9120  depicted in  FIGS. 61B and 61C  can be relatively longer to account for a longer pathway through the digestive tract of the patient. Accordingly, various procedures can be identical to those described above with respect to the stomach S, other than they are performed via the duodenum D. Thus, the foregoing disclosures discussed in the context of passing through the stomach wall will not be repeated, but are incorporated here with all appropriate replacements of the term “stomach” with “duodenum.” 
     Procedures such as just described can have a number of advantages, in various instances. For example, in certain instances, the procedures can be “truly minimally invasive,” in that they do not require abdominal puncture, as is generally the case for videoscopic-assisted retroperitoneal debridement (VARD) or laparoscopic necrosectomy. This can avoid the potential for scarring, hernia, or pancreatico-cutaneous fistula. Furthermore, in some instances, the procedures can be performed under conscious sedation, rather than general anesthesia. General anesthesia can, in some instances, cause long-term systemic inflammation in patients that are already seriously ill. 
     The coring catheter  9120  can be used in other procedures, such as VARD or laparoscopic necrosectomy. Additionally or alternatively, the coring catheter  9120  can be used effectively in various open surgery procedures. 
     Necrotic collections located in the tail of the pancreas, small collections, and collections in patients with low serum albumin levels may not produce a visible bulge and may desirably be accessed under EUS guidance to ensure proper positioning and avoid major vessels. In some instances, necrotic collections that are not close to the stomach or bowel (e.g., within a few centimeters), are extremely large, are dissociated, or are located in distant areas, such as the pelvis may, in some instances, but better treated with procedures other than endoscopic transmural necrosectomy. Further, in some instances, it may be desirable to treat collections that are not walled off with procedures other than endoscopic transmural necrosectomy to reduce chances of spreading necrotic tissue during gas insufflation. 
     In various instances, multiple necrosectomy procedures may be performed over a number of days via a placed stent. For example, in some instances, no fewer than 2, 3, 4, 5, or 6 necrosectomy procedures are achieved through the placed stent to ultimately obtain complete or substantially complete removal of the necrotic tissue. In other instances, even more sessions may take place (e.g., no less than 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18). The repeated sessions may take place over a period of no less than 3, 4, 5, or 6 days or no less than 1, 2, 3, or 4 weeks. Further, in some methods, a necrosectomy procedure is performed directly after placement of a transmural stent, whereas in other methods, a waiting period may follow placement of the stent prior to the (e.g., first) necrosectomy procedure. 
     In some instances, it can be desirable to drain portions of the pancreas prior to proceeding with endoscopic transmural necrosectomies, such as those previously described. For example, in some instances, endoscopic transmural or transpapillary drainage may be conducted prior to any endoscopic transmural necrosectomies. 
     With reference again to  FIGS. 9-16 , in certain embodiments, a device  900  can include a coring catheter, or catheter tube  102  of any suitable variety discussed herein for purposes of coring and suctioning material from a patient. The device  900  can include a Y-fitting  904 , which can include a suction port  902  for application of suction to the catheter tube  102 , and can further include an arm  908  that defines an access channel into the catheter tube  102 . The arm  908  can, such as in the illustrated embodiment, extend rectilinearly from a proximal end of the catheter tube  102 . The arm  908  can accommodate insertion therethrough of any suitable elongated element. The elongated element can be advanced through the catheter tube  102  and, in some embodiments, can extend past a distal end of the catheter tube  102  to manipulate or otherwise disrupt material thereat. For example, as discussed previously with respect to the arm  908 , in the illustrated embodiment, the stylet  700  can be passed through the arm  908  and through the catheter tube  102  and the distal end thereof can contact and disrupt problematic material, such as, e.g., impacted food within the esophagus or any other problematic material discussed herein. That is, the stylet  700  can be referred to as an elongated element, elongated member, or elongated disrupting element or member. 
     In some embodiments, the Y-fitting  904  includes a valve of any suitable variety, such as a Tuohy-Borst valve or adapter. The functioning of an embodiment of such a valve, which can include the compression seal  910  and the threaded cap  914 , has previously been described. 
     In other embodiments, a different elongated member can be inserted through the Y-fitting  904  and through the catheter tube  102  of the device  900  to disrupt target material (e.g., problematic or undesired material) positioned distally past a distal tip of the catheter tube  102 . For example, in various embodiments, any suitable variety of the disruptive (e.g., macerating) devices disclosed in the following U.S. patents and patent application publications is contemplated: U.S. Pat. No. 8,845,621, titled APPARATUS FOR ROTATING MEDICAL DEVICES, SYSTEMS INCLUDING THE APPARATUS, AND ASSOCIATED METHODS, issued Sep. 30, 2014; U.S. Pat. No. 9,107,691, titled APPARATUS FOR ROATATING MEDICAL DEVICES, SYSTEMS INCLUDING THE APPARATUS, AND ASSOCIATED METHODS, issued Aug. 18, 2015; U.S. Pat. No. 10,352,411 titled ROTATIONAL DRIVE APPARATUS WITH RATCHETING MECHANISM, issued Jul. 16, 2019; U.S. Pat. No. 10,376,278, titled TISSUE RESECTORS WITH CUTTING WIRES, HAND OPERATED TISSUE RESECTING SYSTEMS AND ASSOCIATED METHODS, issued Aug. 13, 2019; U.S. Patent Application Publication No. 2014/0142594, titled APPARATUS FOR ROTATING MEDICAL DEVICES, SYSTEMS INCLUDING THE APPARATUS, AND ASSOCIATED METHODS, published May 22, 2014; U.S. Patent Application Publication No. 2017/0189046, titled TISSUE RESECTORS, HAND OPERATED TISSUE RESECTING SYSTEMS, AND ASSOCIATED METHODS, published Jul. 6, 2017; and U.S. Patent Application Publication No. 2018/0228509, titled TISSUE PIERCING ASSEMBLIES, published Aug. 16, 2018. The entire contents of each of the foregoing patents and patent application publications are hereby incorporated by reference herein and form a part of the present disclosure. 
     By way of example, with reference to  FIGS. 62A , in some instances, a manually operated, material-disrupting device  9200  can be formed by combining the disclosures pertinent to at least  FIGS. 9 and 16  of U.S. Patent Application Publication No. 2014/0142594. The device  9200  may also be referred to as a system; in some embodiments, certain components of the device  9200  may be fully separable from each other and/or selectively adjustable relative to each other. The material-disrupting device  9200  can include a driver  9204  that includes a manually operable actuation handle  9205  of any suitable variety, such as disclosed in the aforementioned patents and published patent applications. In the illustrated embodiment, the driver  9204  is manually manipulable, or stated otherwise, is a manual driver. In other embodiments, as discussed below, an automated or power driver may be used. 
     In some embodiments, the actuation handle  9205  can include two handle elements  9206 ,  9207 , and manual contraction or approximation of at least a portion of the two handle elements toward each other causes rotation of an elongated member  9210  portion of the system or device  9200  in a first direction, and separation or distancing of the two handle elements from each other causes rotation of the elongated member  9210  in a second direction opposite the first direction. For example, the device  9200  can include a helically threaded rotational member  9208  that converts translational motion of one or more of the handle elements (e.g., back and forth movement of an upper end of the forward handle element  9207  relative to the back handle element  9206 ) into rotational motion of the elongated member  9210 . In some embodiments, separation of the two handle elements  9206 ,  9207  after an approximation event may occur automatically due to internal biasing of the driver  9204 , such as may be provided by a compression spring  9209 . Any suitable disclosures of the foregoing patents and patent application publications are contemplated with respect to the actuation handle  9205  and the elongated member  9210 . Further details regarding the illustrated driver  9204  will now be provided. 
     With continued reference to  FIGS. 62A and 62B , the illustrated embodiment includes the back and forward handle elements  9206 ,  9207 , which can be gripped by a single hand of a user. In some instances, the back handle element  9206  remains relatively stationary relative to the hand during use, whereas the forward handle element  9207  is repeatedly squeezed to alternatingly approximate and move away from the back handle element  9206 . The forward handle element  9207  can be coupled to the back handle element  9206  at a pivot  9232 . Any suitable pivot arrangement is contemplated. In the illustrated embodiment, the forward handle element includes one or more inward protrusions that are received within an opening of the back handle element  9206  and are rotatable therein. 
     At an upper end of the illustrated back handle element  9206  is a housing  9230  that defines an open chamber with an opening (not shown) at a back end or base thereof. A proximal end of the he compression spring  9209  can be received into the chamber of the housing. A proximal end of the rotational member  9208  can extend through the chamber, through the opening at the base of the housing  9230 . A ledge  9242  can be sized to not pass through the back opening so as to maintain the rear end of the rotational member  9208  in the chamber. In some embodiments, a cap  9220  is coupled to (e.g., screwed onto) the proximal end of the rotational member  9208  so as to be fixed relative thereto. Accordingly, as the rotational member  9208  spins, the cap  9220  may spin in unison therewith. 
     In the illustrated embodiment, the rotational member  9208  includes a thread  9244  that can interact with a shuttle  9250 , which reciprocates back and forth as the forward handle member  9207  is squeezed and released, to impart rotation to the rotational member  9208 . The rotational member  9208  can further include a forward ledge or shelf  9246  and a post  9248 , which are further discussed hereafter. 
     The shuttle  9250  can be received within a barrel  9270 , and the barrel  9270  can be secured to the housing  9230  in any suitable manner. The illustrated barrel  9270  includes linear slots  9272  that run parallel to a longitudinal axis of the driver  9204  and are diametrically opposed. The shuttle  9250  includes diametrically opposed slide protrusions  9250  that fit within the slots. The slide protrusions  9252  are elongated so as to prevent rotation of the shuttle  9250  within the barrel  9270 . The shuttle  9250  further includes pivot protrusions  9254  that fit within openings  9260  defined at an upper end of the forward grip, or forward handle member  9207 . As the bottom end of the forward handle member  9207  rotates about the pivot  9232 , the upper end of the forward handle member  9207  rotates about the pivot protrusions  9254  as the shuttle  9250  moves longitudinally backward (i.e., proximally) and forward (i.e., distally) within the barrel  9270 . Stated otherwise, repeated squeezing and releasing of the forward handle member  9207  can cause linear back-and-forth motion of the shuttle  9250 . Backward motion of the handle element  9207  urges the shuttle  9250  backward, which compresses the spring  9209 . Upon release of the handle element  9207 , the spring  9209  urges the shuttle  9250  and the handle element  9207  forward again. 
     The shuttle  9250  can include any suitable interface for interacting with the thread  9244  of the rotational member  9208  to convert the linear motion of the shuttle  9250  into rotational motion of the rotational member  9208 . For example, the shuttle  9250  can include an internally threaded track  9256  that is complementary to and interfaces with the thread  9244 . In other embodiments, the thread  9244  and the track  9256  can be reversed relative to the components. Each mechanism involving one or more of a thread or track (e.g., helically arranged) may be referred to as a threaded arrangement. Any other suitable rotation-imparting mechanism or system is contemplated. 
     The post  9248  of the rotational member  9208  can extend through a distal opening  9274  defined by the barrel  9270 . The ledge  9246  can be larger than the opening  9274  and can interface with an inner surface of the barrel  9270  to retain the rotational member  9208  within the barrel  9270 . A distal cap  9280  can be attached to the post  9248  in any suitable manner. For example in some embodiments the distal cap  9280  is secured to the post  9248  via threading, adhesives, and/or welding. The distal cap  9280  can rotate in unison with the rotational member  9208 . 
     With reference to  FIG. 62A , the elongate member  9210  can include a distal portion or distal end  9218  and a proximal portion or proximal end  9219 . The distal end  9218  can be inserted into the patient (e.g., through an endoscope and/or through a coring catheter), as discussed further below. The proximal end  9219  can remain at an exterior of the patient (and at an exterior of the endoscope and/or coring catheter) during use. The proximal end  9219  may be fixedly secured to the driver  9204  in any suitable manner. For example, in some embodiments, the proximal end  9219  of the elongated member  9210  can be adhered to one or more of the proximal and distal caps  9220 ,  9280 . In other embodiments, the proximal end  9219  may be selectively secured via one of more of the caps  9220 ,  9280 , such as via a tightening and/or loosing threaded collet. In certain of such embodiments, a length to which the distal end  9218  of the elongate member  9210  extends past the distal cap  9280  may be selected by a user. 
     The distal end  9218  of the elongated member  9210  can include an agitator  9215 . In the illustrated embodiment, the agitator  9215  is a compressible component that can selectively be compressed to a low-profile state for advancement through, e.g., a working channel of an endoscope or a lumen of a catheter. In some embodiments, the agitator  9215  is resilient so as to naturally assume the expanded shape shown. In the illustrated embodiment, the agitator  9215  defines an empty basket shape when in an expanded state. For example, the agitator  9215  includes a plurality (four, in the illustrated embodiment, although other numbers are contemplated) of disruption elements. The disruption elements, when expanded, extend outwardly away from a longitudinal axis A of the elongated member  9210 . Each disruption element defines an arc (more easily seen in other embodiments—see, e.g.,  FIGS. 63, 64, 65 ). Stated otherwise, each disruption element may be preformed to define a curve that extends outwardly away from the longitudinal axis A. In the illustrated embodiment, no portion of the elongated member is oriented along the longitudinal axis A in the region of the agitator  9215 . 
     The agitator  9215  may be introduced through an endoscope or other elongated device with a lumen in a compressed or low-profile state. The agitator  9215  can, in some embodiments, naturally enlarge to the expanded state when advanced past the distal end of the endoscope or other device. 
     In various embodiments, a full stroke (e.g., squeeze) of the handle element  9207  of the actuation handle  9205  may effect 1, 2, 3, 4, 5, 6, 7 or more rotations of the elongated member  9210 . In further instances, the return stroke may effect the same number of rotations, but in the opposite direction. A user may control how quickly or slowly the elongated member  9210  rotates by controlling the rate at which the actuation handle  9205  is squeezed and released. In various embodiments, by rapidly and repeatedly squeezing and releasing, a user may achieve a total number of rotations at a rate of up to, about, or greater than 500, 600, 700, 800, 900 or 1,000 rotations per minute. In some instances, an instantaneous rate of rotation of the elongated member  9210  may exceed the rate of total rotations achievable due to the back and forth motion exhibited in the latter instance. In various embodiments, an instantaneous rate of rotation of greater than about 1,000 or 1,500 rotations per minute may be achieved. Other rates of rotation are contemplated. 
     The elongated member  9210  portion of the device  9200  can be inserted through the Y-fitting  904  and through the lumen of the catheter tube  102  (see  FIG. 9 ), with the expandable agitator  9215  portion of the elongated member  9210  in a compressed state. The agitator  9215  may also be referred to as a cutter, cutting element, scraper, scraping wire or wires, basket, macerator, resector, agitator, disruptor, etc. The agitator  9215  can be positioned at a distal end of a stem or shaft  9217 . 
     The agitator  9215  can be expanded and rotated to cut, macerate, dislodge, or otherwise agitate or disrupt the undesired or problematic material. The disrupted material can be suctioned through the catheter tube  102 . In some instances, the disrupted material is suctioned while the elongated member  9210  remains in place within the catheter tube  102 . In other instances, the elongated member  9210  is removed from the catheter tube  102 , and in further instances, is also removed completely from the Y-fitting  904 , prior to suctioning. In some instances, the agitator  9215  may cut or otherwise disrupt one or more individual or separated pieces of material and, while the agitator  9215  remains at a position distal to the distal tip of the coring catheter  102 , the distal tip of the coring catheter may core or cut the one or more pieces into smaller pieces for suctioning through the catheter  102 . In other or further instances, the agitator  9215  may alter a state of the material, such as from a relatively solid or viscous state to a relatively liquified, slurry-like, or less viscous state and, while the agitator  9215  remains at a position distal to the distal tip of the coring catheter  102 , the coring catheter  102  can apply suction (e.g., relatively high suction) to remove the altered material. 
     In some embodiments, a user may sese, feel, or otherwise receive tactile feedback from the agitator  9215 , and thus from the conditions that the agitator  9215  encounters, as the agitator  9215  rotates. For example, a user may sense when rotation is relatively easy or relatively difficult, or even when binding of the agitator  9215  has occurred. This can enable the user to react quickly (e.g., terminate rotation, speed up or slow down rotation, torque, and/or oscillation, move the agitator longitudinally back and forth with or without rotating the agitator) in a manner that will reduce potential for damage or harm to the patient and/or that will enhance effectiveness of a procedure. 
     In other embodiments, an automated or powered driver may be used in place of the illustrated manual driver. For example, in some embodiments a handheld power drill of any suitable variety may be coupled with and rotate the elongated member  9210 . The power drill may achieve any of the rotational rates (absolute and/or instantaneous) previously described. In some instances, the powered driver may provide less or even no tactile feedback to a user with respect to conditions encountered by the agitator  9215 . 
     In some embodiments, the coring and suctioning device  900  and the agitating device  9200  may be used in an alternating or serial fashion. For example, in some instances, an endoscope may be positioned adjacent to the target material for removal from the patient, such as necrotic material in the pancreas (e.g., from pseudocysts and/or pancreatic ducts), stool impaction within the bowel, mucous or other blockages within the trachea and/or bronchial tree, blood clots (e.g., within the gastrointestinal tract), esophageal food impactions, etc. In various of such instances, specialized endoscopes may be used, depending on the region of the body being accessed. For example, in various instances, the devices  900 ,  9200  may be passed through the working channel of a gastroscope, a duodenoscope, a sigmoidoscope, or a colonoscope, or a bronchoscope. 
     The agitating device  9200  (i.e., the elongated member  9210  thereof) may initially be introduced through the working channel of the endoscope to the target material, and then actuated to rotate and macerate the material. The agitating device  9200  may be removed from the working channel while the endoscope remains in place. The coring and/or suctioning device  900  may then be inserted through the working channel and can core and/or suction away the disrupted material. In some instances, the disruption and suctioning stages can be repeated as necessary or desired. In some instances, each of the devices  900 ,  9200  are used under complete visualization provided by the endoscope. The device  900  and/or the device  9200  can, individually or in cooperation with each other, be used for effective treatment of pancreatitis (e.g., walled-off necroses), bowel impactions, tracheal or bronchial blockages, blood clots, esophageal food impactions, etc. 
     While the foregoing discussion focuses on the illustrative device  900 , which includes the catheter tube  102 , it is contemplated that appropriate features of any of the other catheter tubes and coring devices disclosed herein may be employed with the device  900 , or stated otherwise, that any of the other disclosed coring catheters may be suitably adapted to accommodate the elongated member  9210  of the agitating device  9200  and to simultaneously provide suctioning through the catheter lumen within which the elongated member  9210  is positioned. 
     In still other or further instances, the elongated member  9210  of the agitating device  9200  can be selectively inserted through and removed from any of the catheter or catheter assemblies  100 ,  3004 ,  3304 ,  3404 ,  3504 ,  3604 ,  3704 ,  3804 ,  4004 ,  9120 . For example, in some instances, the catheter or catheter assembly can be inserted into the patient, for example, such that the distal tip is at or near the target site. In some instances, the catheter or catheter assembly is inserted into the patient by being advanced through the working channel (or one of multiple working channels) of an endoscope. The elongated member  9210  of the agitating device  9200  can be inserted through a lumen of the catheter or catheter assembly, with the agitator  9215  in the low-profile state, before or after said insertion of the catheter or catheter assembly. The elongated member  9210  can be advanced past the distal end of the catheter and into the target site, can naturally transition to the expanded state, and can be rotated to agitate or disrupt the target site (e.g., problematic material). In further instances, the elongated member  9210  is then withdrawn from the catheter. The catheter may then be coupled to a source of suction. The catheter may then be used to core and/or suction the agitated material, in manners such as previously disclosed. The coring catheter may subsequently be removed from the patient. For example, the coring catheter may be withdrawn proximally from the endoscope and the endoscope may subsequently be removed, or both the catheter and the endoscope may be withdrawn simultaneously from the patient. 
     In some methods, the catheter may not be coupled to a source of suction and may not be used to core the material. For example, in some embodiments, the catheter or catheter assembly ( 100 ,  3004 ,  3304 ,  3404 ,  3504 ,  3604 ,  3704 ,  3804 ,  4004 ,  9120 ) may be used to reduce friction to facilitate longitudinal and/or rotational movement of the elongated member  9210  of the agitating device. As previously discussed, in some embodiments, an interior surface of the catheter may be lubricious. In various methods, the catheter or catheter assembly is inserted into the patient by being advanced through the working channel (or one of multiple working channels) of an endoscope. The elongated member  9210  of the agitating device  9200  can be inserted through a lumen of the catheter or catheter assembly before or after said insertion of the catheter or catheter assembly. The elongated member  9210  can be advanced past the distal end of the catheter and into the target site, and can be rotated to agitate or disrupt the target site (e.g., problematic material). The catheter may reduce friction for the spinning elongated member  9210 , relative to friction that might otherwise be experienced between the elongated member  9210  and the endoscope in the absence of the catheter. In some embodiments, the catheter is not used to core or suction any of the disrupted material. The elongated member  9210  and the catheter may ultimately be removed from the endoscope. In some instances, at any appropriate stage of certain of these or other methods, standard suction may be applied to the disrupted material via the endoscope. 
     The foregoing methods may be incorporated, as appropriate, into any of the methods disclosed herein. For example, these methods may be used, whether alone or in conjunction with other methods disclosed herein, for treating pancreatitis, food impaction, blockages of the lungs, bowel impaction, etc. 
     In some methods, it may be advantageous to achieve rotation of the agitator  9215  prior to contacting the material that is to be disrupted. For example, with reference again to  FIGS. 60C, 60D, 61B, and 61C , in some instances, the necrotic material  9104  may tend to bind the agitator  9215  when the agitator  9215  is positioned therein while stationary or moving slowly. For example, the consistency of the necrotic material  9104  may be similar to, e.g., peanut butter. With the agitator  9215  positioned in the necrotic material  9104 , it may be difficult to start rotation of the agitator  9215 , as a large amount of torque may be necessary to initiate movement of the agitator  9215 . In some instances, the agitator  9215  is less prone to binding or sticking within the necrotic material  9104  and/or is more efficient at cutting or otherwise disrupting the necrotic material  9104  when the agitator  9215  rotates, e.g., rapidly, before contacting the necrotic material  9104 . Accordingly, in some methods, it can be desirable to achieve rotation of the agitator  9215 , such as relatively large rotational rates of the agitator  9215 , prior to contacting the necrotic material  9104  with the agitator. In various methods, a rate of total rotations per minute and/or a maximum instantaneous rate of rotation of the agitator  9215  can be no less than 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1,000 rotations per minute prior to contacting the agitator  9215  to the necrotic material  9104 . 
     In some embodiments, disruption of the target (e.g., problematic) material may be more efficient with introduction of water or other fluid (e.g., saline) to the material. In some embodiments, sterile water may be delivered to the target material prior to, concurrently with, and/or after cutting, agitation, or other disruption of the target material via the agitator  9215 . 
     In some embodiments, disruption of the target (e.g., problematic) material may be more efficient with longitudinal (e.g., proximal and/or distal) movement of the agitator  9215 . For example, in some embodiments, the elongated member  9210  may be longitudinally fixed relative to the handle  9205 , and the user may urge the handle  9205  forward (distally) and/or backward (proximally) relative to the endoscope to dislodge material and/or to free the agitator  9215  from the material. In other or further instances, the user may advance and/or retract the elongated element  9210  relative to the handle  9205  while maintaining the handle  9205  substantially stationary. In other or further instances, the handle  9205  may be configured to achieve longitudinal movement (e.g., back-and-forth or hammering motion) of the elongated member  9210 , such as in manners disclosed on one or more of the above-identified patents and patent application publications. Accordingly, various methods can include a step of moving the agitator  9215  longitudinally before, after, and/or concurrently with rotation of the agitator  9215 . 
     The foregoing methods may be particularly useful in certain instances of clearing necrotic material from the pancreas, and thus may be readily incorporated into the various methods of treating pancreatitis disclosed herein. Moreover, methods involving other target materials (for example, food impactions, stool impactions, etc.) may similarly include various method steps disclosed above, such as rotating the agitator  9215  prior to contact with the material; introducing water to the material prior to, concurrently with, and/or after agitation of the material; and/or moving the agitator  9215  longitudinally. 
     With respect to necrosectomy procedures, some or all of the foregoing methods may assist in separating the necrotic material from healthy tissue, breaking down the necrotic material into smaller pieces, and/or forming a flowable slurry of the necrotic material. In some methods, the smaller pieces and/or slurry material may be cored and/or suctioned via, e.g., a coring catheter (e.g., those described elsewhere herein), endoscope suction, etc. In other or further methods, the smaller pieces and/or slurry material can drain naturally from the pancreas, through the stent, and into the stomach or duodenum, where it may then pass through the gastrointestinal tract and/or be expelled from the patient through natural processes. 
       FIG. 63  depicts another embodiment of a material-disrupting device  9300  such as those previously described (including those described in the above-mentioned patents and patent application publications), and which can be used in place of the device  9200  in any of the methods disclosed relative thereto. The device  9300  includes a handle  9305 , which in certain embodiments may operate identically to the handle  9205 . The handle  9305  can include comfort grip features. The device  9300  further includes an elongated element  9310  that includes a distal agitator  9315 , a proximal agitator  9316 , and a shaft  9317 . The proximal agitator  9316  is positioned toward a distal end of the shaft  9317 , and the distal agitator  9315  is at a distal end of the proximal agitator  9316 . This arrangement can provide a dual-cutting, or dual-disruption feature. The arrangement may also be referred to as a dual-head agitator. In the illustrated embodiment, the distal and proximal agitators  9315 ,  9316  are differently sized, with the proximal agitator  9316  defining a greater diameter than that of the distal agitator  9315 . In various embodiments, the agitators  9315 ,  9316  can be compressed or compressible to a size that is the same as or only slightly larger than a diameter of the shaft  9317 . The agitators  9315 ,  9316  can expand into the configuration shown for rotational disruption of material. 
     In the illustrated embodiment, the shaft  9317  can comprise a wire of any suitable construction. The shaft  9317  can be relatively flexible in transverse directions or, stated otherwise, can be laterally flexible, while being longitudinally stiff. In various embodiments, the shaft  9317  comprises nitinol or stainless steel. In further embodiments, the agitators  9315 ,  9316  can be formed from the same material as the shaft  9317 , and in further embodiments, a single unitary element may define each of the shaft  9317  and the agitators  9315 ,  9316 . For example, in some embodiments, the expandable agitators  9315 ,  9316  may be formed by laser cutting a distal region of a wire. 
     In various embodiments, including those depicted in  FIGS. 62-65 , it may be desirable for the one or more agitators to be formed of nitinol. The thin strips of nitinol (i.e., the disruption elements), which expand into the illustrated basket or cage shape, can be very flexible. When rotating quickly, these flexible members can cut through or otherwise disrupt damaged or necrotic tissue (for example, in the pancreas), but may merely bend, flex, or deflect from healthy tissue. The flexible members thus may impart little or no damage to healthy tissue. Stated otherwise, the flexible members may pass through the necrotic tissue, thereby disrupting it, but may merely glide over, flex, or otherwise be moved out of the way by healthy tissue. 
     In the illustrated embodiment, the shaft  9317  comprises a nitinol wire having an outer diameter of 0.035 inches. The proximal agitator  9316  defines an outer diameter of 25 millimeters, and the distal agitator  9315  defines an outer diameter of 10 millimeters. Other shapes and sizes are contemplated. 
     In the illustrated embodiment, each agitator  9315 ,  9316  is formed from the single, unitary nitinol wire, through which two orthogonal planes of laser cuts have been made. Accordingly, in cross-section, each of the resulting four agitator members has a substantially 90-degree pie-piece shape, with the arc thereof being at the external surface of the cut member. Other shapes and configurations are contemplated. 
     In some arrangements, the elongated element  9310  can be advanced through the lumen of a coring catheter with the agitators  9315 ,  9316  in a low-profile state. The agitators  9315 ,  9316  can be advanced past the distal end of the coring catheter and expanded. The agitators  9315 ,  9316  can be actuated (e.g., rotated and/or moved axially/longitudinally) back and forth to disrupt material. In some instances, the disrupted material can be suctioned through the coring catheter while the shaft  9317  remains within the lumen of the coring catheter and/or after the elongated element  9310  has been removed from the coring catheter, in manners such as previously discussed. 
     In other instances, and as is true with other agitating devices disclosed herein, the agitating device  9300  may be used in a serial, alternating, or exchange manner with the coring catheter (as previously discussed), or may be used without the coring catheter. For example, in some methods, the agitators  9315 ,  9316  are inserted through the working channel of an endoscope to the target region and are used to disrupt the material. For example, in certain procedures for eliminating necrotic material from the pancreas, the disrupted necrotic material may be suctioned through the endoscope, may be pulled into the stomach or duodenum via some other instrument (e.g., a grasper) inserted through the working channel, or may be left to drain naturally (e.g., through a pre-placed stent) into the stomach or duodenum. 
     In various methods of using the device  9300  (as with other similar devices disclosed herein), two users control the endoscope, the coring catheter, and the material disruption device  9300 , or in other methods, control the endoscope and the disruption device  9300 . For example, a first user (e.g., a doctor or other practitioner) may control the endoscope and the coring catheter. In various instances, either the first user or a second user (e.g., a nurse, technician, or other practitioner) may advance the device  9300  through the coring catheter while the first user maintains the endoscope and coring catheter in a desired configuration within the patient. In further instances, the second user can actuate the handle of the device  9300  to disrupt material via one or more of the agitators  9315 ,  9316 . For example, in some instances, substantially all control of an orientation and/or position of a distal tip of the endoscope, a distal tip of the coring catheter, and the agitators  9315 ,  9316  can be controlled by the first user, whereas the second user controls actuation of the agitators  9315 ,  9316 . In other methods, a first user may similarly control just the endoscope, while a second user operates the agitating device  9300 . 
       FIG. 64  depicts another embodiment of a material-disrupting device  9400  such as those previously described (including those described in the above-mentioned patents and patent application publications). The device  9400  includes an elongated element  9410  that includes an agitator  9415  at a distal end of a shaft  9417 . In the illustrated embodiment, the shaft  9417  comprises a wire having an outer diameter of 0.035 inches. The agitator  9315  defines an outer diameter of 25 millimeters. Other shapes and sizes are contemplated. 
       FIG. 65  depicts another embodiment of a material-disrupting device  9500  such as those previously described (including those described in the above-mentioned patents and patent application publications). The device  9500  includes an elongated element  9510  that includes an agitator  9515  at a distal end of a shaft  9517 . In the illustrated embodiment, the shaft  9517  comprises a wire having an outer diameter of 0.035 inches. The agitator  9515  defines an outer diameter of 10 millimeters. Other shapes and sizes are contemplated. For example, in various embodiments, the outer diameter of the expanded agitator  9515  is within a range of from about 10 to 30, 10 to 25, 10 to 20, 10 to 15, 15 to 30, 15 to 25, 15 to 20, 20 to 30, 20 to 25, or 25 to 30 millimeters, is no less than 10, 15, 20, 25, or 30 millimeters, or is no greater than 10, 15, 20, 25, or 30 millimeters. In various embodiments, the outer diameter of the expanded agitator  9515  is 15, 16, 17, 18, 19, or 20 millimeters. 
     A length of the elongated elements  9210 ,  9310 ,  9410 ,  9510  can be sufficient to permit the end agitators  9215 ,  9315 ,  9316 ,  9415 ,  9515  to pass through the endoscope (e.g., which may have been positioned transorally) and into the target region. Accordingly, for various pancreatitis applications, the length may be sufficient for the agitators to pass through the endoscope into a necrotic portion of the pancreas. In some embodiments, for other applications, the length may be longer or shorter, such as to be on the same general order (although longer than) a combined length of the endoscope with which the elongate element will be used and the driver. 
     Kits can include any suitable combination of the foregoing system components, such as a driver, a elongate member, a coring catheter, and/or an endoscope. The driver and elongate member may be preassembled in some instances, or may be assembled on site in other instances. The kits can include instructions for use, such as previously described (see, e.g.,  FIGS. 55 and 56  and associated discussion). The instructions may recite directions to achieve any of the methods disclosed herein using the various devices and components. Accordingly, any method disclosed herein may be recited as directions within a set of instructions for use. 
     EXAMPLES 3-29 
     Following are examples of illustrative methods, numbered 3 to 29. 
     Example 3. A method comprising: 
     advancing an endoscope to a site within a body of a patient at which problematic material is located, the endoscope defining a channel; 
     delivering a device through the channel of the endoscope to the site at which the problematic material is located, the device comprising a distal end configured to core the problematic material, a proximal end, and a tube that comprises a hollow interior; 
     coring from the problematic material, using the distal end of the device, a piece that is sized to pass through the hollow interior of the tube; and 
     applying suction to the device to pass the piece through the hollow interior of the tube and to move the piece out of the device. 
     Example 4. The method of example 3, wherein the site is within the pancreas of the patient. 
     Example 5. The method of example 3, wherein the site is in the biliary tree of the patient. 
     Example 6. The method of example 5, wherein the site is in the common bile duct of the patient. 
     Example 7. The method of example 5, wherein the site is in a peripheral duct of the patient. 
     Example 8. The method of example 3, wherein a gallstone comprises the problematic material. 
     Example 9. The method of example 8, wherein the gallstone is lodged in the biliary tree. 
     Example 10. The method of example 3, wherein a tumor comprises the problematic material. 
     Example 11. The method of example 10, wherein the tumor is lodged in the biliary tree 
     Example 12. The method of example 3, wherein a kidney stone comprises the problematic material. 
     Example 13. The method of example 12, wherein the kidney stone is within one of a ureter, the bladder, or a kidney of the patient. 
     Example 14. The method of example 3, wherein a blood clot comprises the problematic material. 
     Example 15. The method of example 3, wherein the endoscope is specialized for advancement through the patient to the site. 
     Example 16. The method of example 15, wherein the endoscope is a bronchoscope, and wherein the site is within the bronchial tree of the patient. 
     Example 17. The method of example 15, wherein the endoscope is a colonoscope, and wherein the site is within the colon of the patient. 
     Example 18. The method of example 3, wherein said delivering the device through the channel of the endoscope to the site at which problematic material is located comprises advancing the distal end of the device past a distal end of the endoscope into contact with the problematic material. 
     Example 19. A method comprising: 
     positioning an endoscope within a body of a patient such that a distal end of the endoscope is at a site within the body of the patient at which problematic material is located, the endoscope defining a channel; 
     delivering a catheter tube through the channel of the endoscope to the site at which the problematic material is located, the catheter tube defining a lumen; 
     advancing an elongated member that extends through the lumen of the catheter tube out of the catheter tube and into the problematic material to manipulate the problematic material; and 
     after said advancing the elongated member, applying suction to the catheter tube to remove a portion of the problematic material through the lumen of the catheter tube. 
     Example 20. The method of example 19, wherein said advancing the elongated member out of the catheter tube and into the problematic material comprises piercing and disrupting the problematic material via the elongated member. 
     Example 21. The method of example 20, wherein the elongated member comprises a stylet. 
     Example 22. The method of example 20, wherein the elongated member comprises a pointed distal tip. 
     Example 23. The method of example 19, wherein the elongated member remains within the lumen of the catheter tube during said applying suction to the catheter tube to remove the portion of the problematic material. 
     Example 24. The method of example 19, further comprising removing the elongated member from the catheter tube prior to said applying suction to the catheter tube to remove a portion of the problematic material. 
     Example 25. The method of example 24, further comprising introducing the elongated member into the lumen of the catheter prior to said advancing the elongated member out of the catheter tube and into the problematic material. 
     Example 26. A method of treating pancreatitis, the method comprising: 
     positioning a distal end of an endoscope adjacent to necrotic material within the pancreas of a patient, wherein the endoscope comprises a working channel; 
     advancing a coring catheter through the working channel of the endoscope and into contact with the necrotic material past the distal end of the endoscope; and 
     suctioning at least a portion of the necrotic material through the coring catheter. 
     Example 27. The method of example 26, further comprising: 
     advancing an agitator of a material-disrupting device through the working channel of the endoscope into contact with the necrotic material; and 
     actuating the agitator to disrupt the necrotic material. 
     Example 28. The method of example 27, wherein said advancing the agitator through the working channel of the endoscope comprises advancing the agitator through a lumen of the coring catheter while the coring catheter is positioned within the working channel of the endoscope. 
     Example 29. The method of example 27, further comprising removing the material-disrupting device from the working channel of the endoscope prior to said advancing the coring catheter through the working channel of the endoscope. 
     Although the foregoing detailed description contains many specifics for the purpose of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details can be made and are considered to be included herein. Accordingly, the foregoing embodiments are set forth without any loss of generality to, and without imposing limitations upon, any claims set forth. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. 
     Any methods disclosed herein comprise one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified. 
     As used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a layer” includes a plurality of such layers. 
     In this disclosure, “comprises,” “comprising,” “containing” and “having” and the like can have the meaning ascribed to them in U.S. patent law and can mean “includes,” “including,” and the like, and are generally interpreted to be open ended terms. The terms “consisting of” or “consists of” are closed terms, and include only the component structures, steps, or the like specifically listed in conjunction with such terms, as well as that which is in accordance with U.S. patent law. “Consisting essentially of” or “consists essentially of” have the meaning generally ascribed to them by U.S. patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the compositions nature or characteristics would be permissible if present under the “consisting essentially of” language, even though not expressly recited in a list of items following such terminology. When using an open ended term in the specification, like “comprising” or “including,” it is understood that direct support should be afforded also to “consisting essentially of” language as well as “consisting of” language as if stated explicitly and vice versa. 
     The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and/or certain other steps not described herein may possibly be added to the method. 
     The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term “coupled,” as used herein, is defined as directly or indirectly connected in any suitable manner. Objects described herein as being “adjacent to” each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used. Occurrences of the phrase “in one embodiment,” or “in one aspect,” herein do not necessarily all refer to the same embodiment or aspect. 
     As used herein, the term “substantially” refers to the complete or nearly-complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is “substantially free of” particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable effect thereof. 
     As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. Moreover, for references to approximations (which are made throughout this specification), such as by use of the terms “about” or “approximately,” or other terms, it is to be understood that, in some embodiments, the value, feature, or characteristic may be specified without approximation. For example, where qualifiers such as “about,” “substantially,” and “generally” are used, these terms include within their scope the qualified words in the absence of their qualifiers. For example, where the term “substantially perpendicular” is recited with respect to a feature, it is understood that in further embodiments, the feature can have a precisely perpendicular orientation. 
     As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. 
     Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually. 
     This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described. 
     References throughout this specification to “an example,” if any, mean that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment. 
     Reference throughout this specification to “an embodiment” or “the embodiment” means that a particular feature, structure or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification are not necessarily all referring to the same embodiment. 
     Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than those expressly recited in that claim. Rather, as the following claims reflect, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. 
     The claims following this written disclosure are hereby expressly incorporated into the present written disclosure, with each claim standing on its own as a separate embodiment. This disclosure includes all permutations of the independent claims with their dependent claims. Moreover, additional embodiments capable of derivation from the independent and dependent claims that follow are also expressly incorporated into the present written description. These additional embodiments are determined by replacing the dependency of a given dependent claim with the phrase “any of claims [x] through the claim that immediately precedes this one” where the bracketed term “[x]” is replaced with the number of the most recently recited independent claim. For example, for the first claim set that begins with independent claim  1 , claim  3  can depend from either of claims  1  and  2 , with these separate dependencies yielding two distinct embodiments; claim  4  can depend from any one of claim  1 ,  2 , or  3 , with these separate dependencies yielding three distinct embodiments; claim  5  can depend from any one of claim  1 ,  2 ,  3 , or  4 , with these separate dependencies yielding four distinct embodiments; and so on. 
     Recitation in the claims of the term “first” with respect to a feature or element does not necessarily imply the existence of a second or additional such feature or element. Elements specifically recited in means-plus-function format, if any, are intended to be construed in accordance with 35 U.S.C. § 112(f). Elements not presented in requisite means-plus-function format are not intended to be construed in accordance with 35 U.S.C. § 112(f). Embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.