Patent Publication Number: US-2021169464-A1

Title: Tissue retraction devices, systems, and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional patent Application 62/943,885, filed Dec. 5, 2019, which application is incorporated herein by reference in its entirety for all purposes. 
    
    
     FIELD 
     The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to tissue traction devices, e.g., for endoscopic procedures such as tissue dissection, and related methods of use thereof. 
     BACKGROUND 
     Accurately and efficiently performing an endoscopic tissue resection/dissection procedure includes the ability to maintain traction as the boundaries of the target tissue are dissected. Traction systems may be unable to maintain or adjust tension applied to the target tissue, possibly obstructing a medical professional&#39;s view of the target tissue and/or interfering with accessory tools. These complications may directly contribute to increased procedures time, complexity, and risk of perforation or bleeding. 
     It is with these considerations in mind that the improvements in the tissue traction devices and related methods of use of the present disclosure may be useful. 
     SUMMARY 
     The present disclosure, in its various aspects, is directed generally to medical devices, and more specifically to tissue traction devices, traction methods, and related delivery systems. Embodiments according to the present disclosure, including as described herein, may decrease complications around tissue resection procedures, such as visualization, procedure time, and procedure complexity. In an aspect, a tissue traction device may include a first clip comprising opposable jaws. The device may include a traction band having a first end, a second end, a length therebetween and extending along a longitudinal axis. The band may have a first aperture at the first end. A second aperture may be at the second end of the band. A first jaw of the opposable jaws of the first clip may be disposed through the first aperture. 
     In various embodiments described here or otherwise, the second aperture may extend along the longitudinal axis toward the first aperture. The second aperture may have a diameter that is larger than an outer diameter of the first end of the traction band. The second end of the traction band may be extendable away from a second jaw of the opposable jaws in a deployed configuration. A third aperture maybe along the traction band between the first aperture and the second aperture. A second clip may be at least partially disposable through the second aperture. The first jaw of the first clip may include a wall extending substantially radially from the first jaw adjacent the traction band. 
     In an aspect, a tissue traction device may include a traction band having a first end, a second end, a length therebetween and extending along a longitudinal axis. A first connector body may be coupled to the first end of the traction band, and a second connector body coupled to the second end of the traction band. A first filament may extend from the first connector body and away from the traction band, and a second filament extending from the second connector body and away from the traction band. A loop may be formed at each filament. 
     In various embodiments described here or otherwise, one of the first connector body or the second connector body may further comprise a lumen and one of the filaments extends within the lumen. A rod may reversibly extendable within the lumen configured to couple the filament to one of the first connector body and the second connector body. The filament may include a midportion extendable within the lumen and two ends comprising loops extendable out of the lumen. A first loop of the filament may be configured to be engaged by a clip and anchored to a tissue, and wherein a second loop of the filament is configured to be pulled to release the filament from one of the first connector body and the second connector body. The midportion may be coupled to an anchoring element within the lumen. An overtube may be disposed about the traction band. One of the filaments may extend through an aperture of filament having a bulbous portion having a width that is longer than the aperture. 
     In an aspect, a method of resecting a target tissue may include coupling a first end of a traction band to the target tissue. A second end of the traction band may be coupled to another tissue. A body lumen comprising the target tissue may be insufflated thereby increasing a tension in the traction band. The target tissue may be resected. 
     In various embodiments described here or otherwise, the body lumen may be suctioned thereby decreasing a distance between the target tissue and the other tissue. The body lumen may be ventilated thereby decreasing a distance between the target tissue and the other tissue. A midportion of the traction band may be coupled to a third tissue. The traction band may be released from the other tissue. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting embodiments of the present disclosure are described by way of example with reference to the accompanying figures, which are schematic and not intended to be drawn to scale. For example, devices may be enlarged so that detail is discernable, but is intended to be scaled down in relation to, e.g., fit within a working channel of a delivery catheter or endoscope. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures: 
         FIG. 1  illustrates a tissue traction device deployed in a body lumen, according to an embodiment of the present disclosure. 
         FIG. 2A  illustrates a tissue traction device having a traction band disposed on a jaw of a clip, in accordance with an embodiment of the present disclosure. 
         FIG. 2B  illustrates the tissue traction device of  FIG. 2A  disposed within a sheath. 
         FIG. 2C  illustrates the tissue traction device of  FIGS. 2A and 2B  distal to the sheath of  FIG. 2B  for delivery. 
         FIG. 2D  illustrates the tissue traction device of  FIGS. 2A-2C  with the clip being oriented toward a target tissue. 
         FIG. 2E  illustrates the tissue traction device of  FIGS. 2A-2D  with the clip engaged with the target tissue and a second clip being oriented toward an aperture of the traction band. 
         FIG. 2F  illustrates the tissue traction device of  FIGS. 2A-2E  with the second clip engaged with another tissue. 
         FIG. 3A  illustrates a tissue traction device having a traction band disposed on a jaw of a clip, in accordance with an embodiment of the present disclosure. 
         FIG. 3B  illustrates a tissue traction device having a traction disposed on a jaw of a clip, in accordance with an embodiment of the present disclosure. 
         FIG. 3C  illustrates a traction band, in accordance with an embodiment of the present disclosure. 
         FIG. 3D  illustrates a traction band, in accordance with an embodiment of the present disclosure. 
         FIG. 3E  illustrates a traction band, in accordance with an embodiment of the present disclosure. 
         FIG. 3F  illustrates a traction band, in accordance with an embodiment of the present disclosure. 
         FIG. 4  illustrates a tissue traction device, according to an embodiment of the present disclosure. 
         FIG. 5A  illustrates a connector body, in accordance with an embodiment of the present disclosure. 
         FIG. 5B  illustrates a cross-sectional view of a connector body with a filament, in accordance with an embodiment of the present disclosure. 
         FIG. 5C  illustrates a tissue traction device including connector bodies delivered into a body lumen, in accordance with an embodiment of the present disclosure. 
         FIG. 5D  illustrates filament of a connector body being formed into a loop about a mandrel, in accordance with an embodiment of the present disclosure. 
         FIG. 6A  illustrates a filament with a knot, in accordance with an embodiment of the present disclosure. 
         FIG. 6B  illustrates a traction band with filaments extending from ends of the traction band, in accordance with an embodiment of the present disclosure. 
         FIG. 6C  illustrates a filament extending out of a connector body. 
         FIG. 6D  illustrates a filament extending from a connector body and coupled to an anchoring element, in accordance with an embodiment of the present disclosure. 
         FIG. 6E  illustrates a shaft crimped to a filament, in accordance with an embodiment of the present disclosure. 
         FIG. 6F  illustrates a heat-formed bulbous portion of a filament, in accordance with an embodiment of the present disclosure. 
         FIG. 6G  illustrates a filament extending through an aperture of a jaw of a clip, in accordance with an embodiment of the present disclosure. 
         FIG. 7  illustrates a tissue traction device delivered within a body lumen, in accordance with an embodiment of the present disclosure. 
     
    
    
     It is noted that the drawings are intended to depict only typical or exemplary embodiments of the disclosure. Accordingly, the drawings should not be considered as limiting the scope of the disclosure. The disclosure will now be described in greater detail with reference to the accompanying drawings. 
     DETAILED DESCRIPTION 
     As used herein, “proximal end” refers to the end of a device that lies closest to the medical professional along the device when introducing the device into a patient, and “distal end” refers to the end of a device or object that lies furthest from the medical professional along the device during implantation, positioning, or delivery. 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include one or more particular features, structures, and/or characteristics. However, such recitations do not necessarily mean that all embodiments include the particular features, structures, and/or characteristics. Additionally, when particular features, structures, and/or characteristics are described in connection with one embodiment, it should be understood that such features, structures, and/or characteristics may also be used in connection with other embodiments whether or not explicitly described unless clearly stated to the contrary. 
     All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about”, in the context of numeric values, generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure. Other uses of the term “about” (i.e., in a context other than numeric values) may be assumed to have their ordinary and customary definition(s), as understood from and consistent with the context of the specification, unless otherwise specified. The recitation of numerical ranges by endpoints includes all numbers within that range, including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     The detailed description should be read with reference to the drawings, which are not necessarily to scale, depict illustrative embodiments, and are not intended to limit the scope of the invention. 
     A number of medical procedures, including along the digestive and/or biliary tract, utilize medical devices to access tissue intended for removal (e.g., “target tissue”) within the body. For example, in some current medical procedures (e.g., endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR), Peroral Endoscopic Myotomy (POEM), cholecystectomy, Video-Assisted Thoracoscopic Surgery (VATS)), physicians may utilize an endoscope or similar medical device to access and remove diseased lesions. Further, as part of such procedures, a physician may utilize an endoscope capable of both accessing the target tissue site while also permitting a resecting device to be deployed therethrough to resect target tissue. Additionally, in some instances, an endoscope may incorporate features which assist the physician in visualizing and performing the tissue dissection/resection procedure. For example, some endoscopes may include a light and/or camera designed to illuminate and/or visualize the body lumen as the endoscope is navigated and positioned adjacent to the target tissue site. Additionally, some endoscopes may also include a lumen (e.g., a working channel) through which a resecting device, grasping member, delivery catheter for the same, or other accessory devices, may be deployed and utilized. Additional visualization methods may be alternatively or additionally employed, e.g., fluoroscopy. 
     While physicians are becoming more proficient at resecting diseased lesions from within the body (e.g., within the digestive tract, abdominal cavity, thoracic cavity, etc.), present traction methods may continue to be inefficient to the physician. For example, in some instances poor visualization and poor ability to engage and manipulate tissue may result in a prolonged tissue dissection procedure. An aspect of EMR/ESD that may be difficult is the positioning and maneuvering (e.g., traction) of a resected tissue flap during and after resecting. In some EMR/ESD procedures, physicians may use separate devices to provide a means of tissue traction. Such procedures may include multiple device exchanges and extended procedure times. Such systems may be unable to maintain or adjust tension applied to the target tissue, and/or may maintain or adjust tension applied to the target tissue in an inefficient or inconsistent manner. 
     Referring to  FIG. 1 , an embodiment of a tissue traction device is illustrated as delivered and applying tension between a target tissue  104  and another tissue portion  138 . A traction band  114  is coupled to a first clip  112  at a first end of the traction band  114 . The first clip  112  is coupled to the target tissue  104  for resection. A second end of the traction band  114  is coupled to a second clip  111 . The second clip  111  is coupled to the other tissue portion  138  such that the traction band  114  is in tension. A resecting tool  120  is delivered toward the target tissue  104  via an endoscope  106 . As the target tissue  104  is resected, the traction band  114  pulls the first clip  112  and the target tissue  104  substantially toward the second clip  111  such that visualization between the endoscope  106 , the tool  120 , and the target tissue  104  is maintained. 
     Referring to  FIG. 2A , one example of an embodiment of a traction band  200  according to the present disclosure is illustrated. The traction band  200  has a first end  201 , a second end  202 , and a length therebetween extending along a longitudinal axis of the traction band  200 . The first end  201  includes a first aperture  204 . The traction band  200  is coupled to a clip  230 . The clip  230  includes first and second opposable jaws  231 ,  232 . In embodiments, the clip  230  may be a single-use hemostasis clip, and in other embodiments, the clip  230  may be a repositionable clip. The first jaw  231  is disposed through the first aperture  204  of the traction band  200 . The first aperture  204  has an inner diameter that substantially matches an outer circumference of a portion of the first jaw  231 . In some embodiments the inner diameter of the first aperture  204  may be smaller than the outer diameter of the first jaw  231  but may be stretchable to accommodate the first jaw  231 . Thus, the traction band  200  may be connected to the first jaw  231  by a friction fit. The jaws  231 ,  232  include a midportion  234  having a wall extending substantially radially from the jaws  231 ,  232 . The midportion  234  is adjacent and distal to the first end  201  of the traction band  200 . The midportion  234  may assist in preventing translation of the traction band  200  along the first jaw  231 . The second end  202  of the traction band  200  includes a second aperture  206 . The second aperture  206  has a diameter that is larger than a diameter of the first aperture  204  and is also larger than a width of the first end  201 . In embodiments, the diameter of the second aperture  206  may be sized to receive at least a portion of a single-use hemostasis clip and/or a repositionable clip (see  FIGS. 2E-2F ). The traction band  200  is coupled to the clip  230  such that the second end  202  is extendable away from the jaws  231 ,  232  by a linear portion  208  extending between the first end  201  and the second aperture  206 . 
     With reference to  FIG. 2B , the clip  230  and traction band  200  of  FIG. 2A  may be loaded into a sheath  250 . The traction band  200  is coupled to the first jaw  231  of the clip  230  such that the traction band  200  is extends substantially parallel along and radially farther from an axis   of the sheath  250  than the first jaw  231  is from the axis  . The clip  230  is oriented within the sheath  250  such that the jaws  231 ,  232  and the second end  202  of traction band  200  are oriented distally. The traction band  200  is positioned within the sheath  250  outside of the jaws  231 ,  232  such that the traction band  200  may not be damaged by the jaws  231 ,  232 . In the orientation depicted in  FIG. 2B , the clip  230  and traction band  200  may be translated through the sheath  250  such that the traction band  200  maintains a substantially linear orientation without entanglement. Alternatively, the traction band  200  may be oriented between the jaws  231 ,  232  within the sheath  250  such that friction between the traction band  200  and the sheath  250  may be reduced. 
     With reference to  FIG. 2C , the sheath  250  is retracted from the clip  230  and traction band  200  and/or the clip  230  and traction band  200  are distally translated out of the sheath  250 . In some embodiments, the sheath  250  may remain stationary and the clip  230  and the traction band  200  may be extendable distally. The jaws  231 ,  232  are oriented distally for engaging tissue and deployment, and the second end  202  of the traction band  200  is oriented away from the jaws  231 ,  232  such that the second end  202  is visible and does not interfere with operation of or become damaged by the jaws  231 ,  232 . 
     With reference to  FIG. 2D , the clip  230  may be oriented toward and delivered to a target tissue  240  such that the jaws  231 ,  232  engage the target tissue  240 . An endoscope  252  or other visualization and/or delivery instrument may be used to visualize and orient the sheath  250  and clip  230  toward the target tissue  240 . The clip  230  may be positioned (i.e., rotated, extended, etc.) such that the traction band  200  is positioned with the second end  202  of the traction band  200  extending away from the jaws  231 ,  232  and/or target tissue  240 . The traction band  200  may have at least a portion that is stiff enough such that the traction band  200  may support the weight of the second end  202  of the traction band  200  away from the jaws  231 ,  232 , as illustrated in  FIG. 2D  and in  FIG. 2E . In embodiments, the stiffer portion may be integral to the traction band  200  and in other embodiments, the stiffer portion may be a separate component attachable to the traction band  200 . 
     With reference to  FIG. 2E , the clip  230  is engaging the target tissue  240  such that the second end  202  of the traction band  200  is oriented away from the jaws  231 ,  232  and the target tissue  240 . A second clip  234  is introduced in the vicinity of the target tissue  240 . The second clip  234  can orient its jaws  236  toward the second end  202  of the traction band  200  such that the jaws  236  of the second clip  234  can engage the second aperture  206  of the traction band  200 . The second aperture  206  is larger than the first aperture  204  such that the second aperture  206  is more easily visible and engageable than the first aperture  204 . 
     Referring to  FIG. 2F , the second clip  234  may be delivered to another tissue  242  while engaged with the second end  202  of the traction band  200 . Because the first end  201  of the traction band  200  is substantially fixed with respect to the target tissue  240  via the first clip  230 , the traction band  200  can apply tension to the target tissue  240  by the second clip  242  pulling the second end  202  away from the first end  201 . 
     Referring to  FIGS. 3A and 3B , embodiments of a traction band  300  of a tissue traction device are illustrated including a third aperture  313 . A first aperture  311  at a first end  301  of the traction band  300  is disposed about a jaw  331  of the clip  330 . A second end  302  of the traction band  300  has a second aperture  312 . The second aperture  312  extends along a longitudinal axis   of the traction band  300  toward the first aperture  311 . The traction band  300  is oriented such that the second end  302  is oriented away from the clip  330 . With reference to  FIG. 3B , the traction band  300  may also include a third aperture  313 . The third aperture  313  extends along the longitudinal axis   of the traction band  300  toward the first aperture  311  and substantially parallel with the second aperture  312 . The second and third apertures  312 ,  313  may be engaged by one or more additional clips or other medical instruments. The length of the second and third apertures  312 ,  313  extend substantially along the length of the band  300  from the second end  302  to the first end  301  proximate the first aperture  311 . 
     With reference to  FIGS. 3C-3F , embodiments of tractions bands  300  may include various apertures through the traction band  300 . For example, in  FIG. 3C , the first aperture  311  may be a substantially circular aperture  311  at the first end  301  of the traction band  300  for receiving at least a portion of a jaw of a first clip. The second aperture  312  may be at the second end  302  of the traction band  300  and extends substantially along the length of the band  300  from the second end  302  to the first end  301  proximate the first aperture  311 . The second aperture  312  may be a slot that extends toward the first aperture  312  along the longitudinal axis  13  of the traction band  300 . The first aperture  311  may have a smaller diameter than a diameter of the ends of the slot of the second aperture  312 . The first aperture  311  may be used to couple to a first clip by preloading the traction band  300  onto the first clip before a procedure. The second aperture  312  may be engaged by a second clip after the first clip is delivered into the body. In  FIG. 3D , the traction band  300  may include only a single aperture  311  extending along the longitudinal axis  13  of the traction band  300  that may be engaged by one or more clips and may be preloaded attached to one or more clips. In  FIG. 3E , the first aperture  311  of the traction band  300  may be at the first end  301  and extend partially along the longitudinal axis  13  toward the second end  302  of the traction band  300 . The second aperture  312  may be at the second end  302  and may partially extend along the longitudinal axis  13  toward the first end  301 . In  FIG. 3F , the embodiment of  FIG. 3E  may further include a third aperture  313  between the first and second aperture  311 ,  312  extending along the longitudinal axis  13 . A fourth aperture  314  may extend between the first and second apertures  311 ,  312  that is substantially parallel with the third aperture  313 . Any of the apertures of a traction band  300  may be engaged by a clip and/or additional medical instruments to position, orient, and/or adjust the magnitude or angle of tension in the traction band  300 . 
     Referring to  FIG. 4 , an embodiment of a traction device is illustrated including a traction band  400  having first  401  and second ends  402 . The traction band  400  includes an elastic, stretchable body  404  between the ends  401 ,  402 . An elongate tubular hollow body alignment member  408  is extendable at least partially over the elastic body  404 . The alignment member  408  may align and/or orient the traction band  400  within a working channel of a scope, other introducer sheath, or catheter during device manipulation. The alignment member  408  may reduce friction between the elastic body  404  and a working channel. A clip  430 , including jaws  432 , has one of its jaws  432  coupled to the first end  401  of the traction band  400  via a first connector body  411 . A second connector body  412  is coupled to the second end  402  of the traction band  400 . A filament  420  extends from the second connector body  412  away from the traction band  400 . A loop  424  is formed at an end of the filament  420 . The filament  420  extends from the second connector body  412  to the loop  424  by a neck portion  422 . The neck portion  422  may extend the loop  424  farther from the connector body  412  such that the loop  424  is easier for a medical professional to visualize and manipulate with an instrument. The tissue traction device may be delivered by a delivery device  450  by the medical professional by operating a handle of the delivery device. The clip  430  may be used by the medical professional to deliver the first end  401  of the traction band  400  that is coupled to the clip  430  to a tissue. The loop  424  may be engaged by another device such as an additional clip. The additional clip may be moved to fix the loop  424  to another anatomy or another portion of the tissue such that the second end  402  of the traction band  400  extends away from the first end  401 . In this position, the traction band  400  is placed in greater axial tension compared to a relaxed state of the traction band  400  that is illustrated in  FIG. 4 . The tissue traction device of  FIG. 4  may be used substantially similar to that of  FIG. 1  discussed above. 
     Referring to  FIG. 5A , an embodiment of a connector body  510  (which may alternately be referenced as a bobbin, without intent to limit) is illustrated having a first end  515 , a second end  516 , and a lumen  518  therethrough. The connector body  510  has a larger diameter at the second end  516  than at the first end  515 . A traction band and/or an alignment member may have an outer diameter larger than the first end  515  and smaller than the second end  516  such that the traction band and/or alignment member may couple to the connector body  510  by being disposed about the first end  515  but not extending past the second end  516 . The connector body  510  includes a saddle region  519  having a smaller diameter than that of the first end  515  and the second end  516 . The saddle region  519  may provide a region for a traction band and/or an alignment member to frictionally couple to the connector body  510  (e.g., between the saddle region  519  and the first end  515 , along a portion of or the entirety of the saddle region  519 , the saddle region  519  may be a region for the application of adhesive to join the connector body to the traction band or alignment member, etc.). The second end  516  may include an atraumatic curved surface that may reduce friction with working channels, devices, or anatomies compared to an edge. A connector body  510  may be rotatably coupled to a traction band, e.g., with an aperture, a cavity, or a lumen of a traction band, such that the connector body  510  may rotate freely about a longitudinal axis of the connector body  510  and/or the traction band such that there is minimal twisting of the traction band. 
     With reference to  FIG. 5B , a cross-sectional view of an embodiment of a connector body  510  is illustrated including a lumen  518 . A filament  520  having a loop at each of a first end  521  of the filament  520  and a second end  522  of the filament  520  is disposed within the lumen  518 . The filament includes a midportion  523  extending through the lumen  518 . The first and second ends  521 ,  522  of the filament  520  extend outside of the lumen  518  on the same side of the connector body  510 . A cannula  526  dimensioned to compliment the lumen  518  (e.g., substantially similar diameters and lengths depending on a desired fit) is slidingly disposed within the lumen  518 . The cannula  526  temporarily couples the midportion  523  of the filament  520  within the lumen  518  by the midportion  523  extending along the cannula  526  within the lumen  518 . The at least part of the midportion  523  may be pinched between the cannula  526  and the connector body  510  within the lumen  518 . With reference to  FIG. 5C , the connector body  510  may be coupled to a traction band  500 . In use, a first end  501  of the traction band  500  may be coupled to a target tissue  540  by a first clip  530  while a second end  502  of the traction band  500  may be coupled to another tissue portion  542  by a second clip  534 . The second clip  534  may couple the traction band  500  to the other tissue portion  540  by engaging a loop at the first end  521  of the filament. In this position, a loop at the second end  522  may be left freely hanging from the connector body  510 . The traction band  500  may be extended between the target tissue  540  and the other tissue portion  542  as described throughout the disclosure. The cannula  526  coupling the midportion  523  of the filament  520  to the connector body  510  may fit tightly enough within the lumen  518  such that the traction band  500  may be tensioned without uncoupling the cannula  526  and midportion  523  from the lumen  518 . The filament  523  may be uncoupled from the connector body  510  by an instrument engaging the loop of the second end  522  of the filament  520  and pulling on the second end  522  such that the fixed first end  521  and tensioned second end  522  dislodge the cannula  526  and midportion  523  from the lumen  518 . The portions of the filament  520  extending between the ends  521 ,  522  and the lumen  518  may be substantially equal in length or may differ in length from each other. Varying lengths of these portions of the filament  520  may allow a physician to choose a preferred length for attaching one of the ends  521 ,  522  to an anatomy. The devices may be left within the body to be passed naturally, or some or all of the devices may be removed from the body after a procedure. 
     With reference to  FIG. 5D , an embodiment of a connector body  510  is illustrated with a filament  520  extending from the connector body  510 . The portion of the filament  520  outside of the connector body  510  is being formed into a loop about a mandrel  560 . 
     Referring to  FIGS. 6A-6G , embodiments of a filament  620  may be coupled to a device in various ways.  FIG. 6A  illustrates a filament  620  having a knot  628  at an end that may be tied to, embedded within, or provide a bulbous stop against a device.  FIG. 6B  illustrates a traction band  600  with two filaments  620  extending from each end of the traction band  600 . The filaments each include a knot  628  embedded within the traction band  600 . One or more knots  628  of a filament  620  may be embedded within a traction band  600 , e.g., by overmolding the traction band  600  about the knots  628 .  FIG. 6C  illustrates a connector body  610  with a filament  620  extending out of a lumen  618  of the connector body  610 . The filament  620  may be coupled to the connector body  610 , e.g., by a knot.  FIG. 6D  illustrates a connector body  610  with a midportion  623  of a filament  620  extending through a lumen  618  of the connector body  610 . The midportion  623  is coupled to an anchoring element  629  having a diameter larger than a diameter of at least a section of the lumen  618  such that the anchoring element  629  coupled to the midportion cannot translate through the lumen  618 . The midportion  623  may be tied, looped, welded, or otherwise adhered to the anchoring element  629 .  FIG. 6E  illustrates an end of a filament  620  with a bulbous body  627  coupled to the filament  620 . The bulbous body  627  may be larger than a diameter of an aperture or lumen of another device such that the bulbous body  627  may anchor the filament  620  to the device. The bulbous body  627  may be coupled to the filament  620  by crimping, melting, welding, or otherwise adhering the bulbous body  627  to the filament  620 .  FIG. 6F  illustrates an end of a filament  620  having a bulbous portion  626 . The bulbous portion  626  may be larger than a diameter of an aperture or lumen of another device such that the bulbous portion  626  may anchor the filament  620  to the device. The bulbous portion  626  may be formed by at least partially melting the filament such that it forms into a larger diameter bulbous portion  626  and/or additional material may be formed about the filament  620 . It will be appreciated that the proportions of the bulbous portion  626  may differ from those illustrated. For instance, the bulbous portion may have a length substantially equal to the width thereof. A clip may be coupled to a filament end (that may include a loop) by the filament extending through an aperture in a jaw of the clip. For example,  FIG. 6G  illustrates a clip  630  with an aperture  635  through one of the jaws  631  of the clip  630 . A filament  620  having a bulbous portion  626  is extending through the aperture  635 . The bulbous portion  626  has a wider diameter than the aperture  635  such that the filament  620  cannot be pulled out of the aperture  635  in at least one direction without applying enough force to deform the bulbous body  626 . 
     Referring to  FIG. 7 , an embodiment of a tissue traction system is illustrated within a body lumen  770 . A traction band  700  is attached to a target tissue  740  at one end by a first clip  730  and the traction band  700  is attached to another portion of tissue  742  of the body lumen  770  at a second end by a second clip  732 . The traction band  700  may assist a medical professional that is operating a cutting instrument  782  to resect the target tissue  740  by applying tension to the target tissue  740  such that the medical professional may more easily access the perimeter of the target tissue with the cutting instrument  782  and/or more easily visualize the anatomy or devices, e.g., via a scope  780 . A tension in the traction band  700  may be adjusted if the target tissue  740  and the other tissue portion  742  of the body lumen  770  are moved in relation to each other. Tension may be increased by insufflating the body lumen  770  with a fluid (e.g., atmospheric air, CO 2 , or the like through a working channel of the scope  780 ) such that the volume of the body lumen increases, separating the target tissue  740  from the other tissue portion  742  and thereby increasing tension in the traction band  700 . Tension may be decreased by suctioning or passively ventilating fluid or gas (atmospheric air, CO 2 , etc.) from the body lumen  770  (e.g., through a working channel of the scope  780 ) such that the volume of the body lumen decreases, bringing the target tissue  740  closer to the other tissue portion  742  and thereby decreasing tension in the traction band  700 . Either insufflation or suction may be employed to a body lumen before, during, or after a traction device is delivered. 
     In various embodiments, a clip may be rotatable to rotate or rotate about a traction band. A clip may be repositionable before, during, and/or after a procedure. A clip may be a single use clip (i.e., not repositionable). A medical procedure such as resecting of a tissue may be performed with a traction device coupled to one or more tissues in tension. During and/or after the procedure, tension may be released by severing a portion of the device, such as a filament, a traction band, an alignment member, a neck portion, and/or a loop. Examples of tissue traction devices and associated instruments may include, but are not limited to, those described in U.S. Provisional Patent Application with Docketing number 8150.0674Z, filed Oct. 18, 2019, and titled “Filament Cutting Devices, Systems, and Methods,” and U.S. patent application Ser. No. 15/930,620, filed May 13, 2020, and titled “Tissue Traction Bands and Methods for Tissue Traction,” each of which are herein incorporated by reference in their entirety and for all purposes. 
     In various embodiments, a traction device may include no filaments, one filament, or multiple filaments. A traction band may include an internal filament extending between ends of a traction band that may prevent the traction band from stretching beyond a desirable length. A filament of a traction device may comprise, extend to, or be coupled to one or more loops that can be various shapes and diameters. 
     In various embodiments, a filament may comprise various shapes such as a loop, a hook, an anchor, a knot, a barb, an eyelet, a combination thereof, or the like. In various embodiments, a filament may comprise a polymer strand (e.g., polypropylene, polyester, nylon, polyethylene, elastic polymers including thermoplastic elastomer (TPE), polyisoprene, silicone, and/or the like), a metal wire (e.g., stainless steel, titanium, cobalt-chrome, nitinol, and/or the like), and/or a natural fiber (e.g., cotton, wool, silk, and/or the like). A filament may have a material strength configured to fail at a pre-determined load as a safety feature to limit an amount of tension in the traction band and the surrounding tissue. One or more filaments may be visually marked such that the filaments are visually distinguishable with respect to other filaments. For example, the filaments may vary in colors, patterns, or radiopacity such that a medical professional can easily identify a selected filament meant for fixation to a target tissue, an anchoring tissue, a second anchoring tissue, for releasing from a connector body, etc. 
     In various embodiments, a traction band and/or an elastic body of a traction band may comprise a compliant or semi-compliant material (e.g., thermoplastic elastomer (TPE), REZILIENT™ Rx15A, MEDALIST™ MD-16110, polyethylene terephthalate (PET), elastic polymers, rubbers, plastics, etc.). The traction band may be an elongate cylindrical tube and may be formed hollow or solid. Materials may be elastic with a lower durometer and lower tensile modulus compared to materials of other devices involved with a medical procedure. A transparent or opaque material may be used. 
     In various embodiments, some steps of assembling a tissue traction device may occur outside of the patient&#39;s body, while other steps involved in assembling the tissue traction device may occur within the patient. The steps described herein do not necessarily occur in a specific order and/or timing. 
     The medical instruments used with various embodiments of the devices, systems, and methods herein are not limited to those illustrated and discussed but may include a variety of medical instruments (e.g., ablative elements, biopsy needles, injection needles, scissors, graspers, clips, etc.). 
     In various embodiments, an access area beneath and about a target tissue to be resected by a medical professional may be visualized. Visualization may be optical, fluoroscopic, ultrasonic, etc. The visualization of the area beneath and about the target tissue may not be adequately revealed for the medical professional to manipulate a medical instrument to the access area to resect the target tissue. The medical professional may deliver and deploy a tissue traction device or system to the target tissue and an anchoring tissue at a length and/or at a tension that reveals the access area for the procedure. The medical professional may adjust the length or tension of the system based on visualization of the target tissue or access area. 
     In various embodiments, filament may be engaged with a variety of different fasteners configured to engage a tissue traction device to a tissue, such as a clip, an anchor, a screw, a pin, or the like. For example, a clip contemplated for use with a tissue traction device may include a biased-open configuration configured to move to a closed/clamped configuration upon actuation by a handle assembly. In addition, or alternatively, a tissue clip contemplated for use with a disclosed tissue traction device may include a biased-closed configuration configured to move an open configuration upon actuation of a distal end effector (e.g., squeezing) by a proximal handle assembly. In addition, or alternatively, fasteners other than detachable/releasable tissue clips may be used to secure/engage the attachment members of the disclosed tissue traction device to the wall of a body lumen, such as non-repositionable clips. Examples of fasteners may include, but are not limited to, those described in U.S. patent application Ser. No. 15/930,604, filed May 13, 2020, and titled “Tissue Clip Devices, Systems, and Traction Methods,” U.S. patent application Ser. No. 16/668,341, filed Oct. 30, 2019, and titled “Clip Devices, Systems, and Methods for Engaging Tissue,” and in U.S. Patent Application Publication number US2018/0263614, filed Mar. 19, 2018, published Sep. 20, 2018, and titled “Tissue Retraction Device and Delivery System,” all of which are herein incorporated by reference in their entirety and for all purposes. 
     In various embodiments, a method of retracting tissue may include delivering a tissue traction device to a target tissue. A first filament and/or connector body extending from a first end of a traction band may be attached to the target tissue. A second filament and/or connector body extending from a second end of the traction band device may be attached to another portion of tissue. The target tissue may be resected. A tension, and/or length of the tissue traction device, applied by the tissue traction device to the target tissue may be adjusted. One or more filaments and the target tissue may be engaged by a clip. One or more filaments and the other tissue portion may be engaged by a clip. An area of access beneath the target tissue may be visualized and a position of any of the devices may be adjusted based on the visualized area of access. 
     In various embodiments, a method of resecting a target tissue may include coupling a first end of a traction band to the target tissue. A second end of the traction band may be coupled to another tissue. A body lumen comprising the target tissue may be insufflated thereby increasing a tension in the traction band. The target tissue may be resected. The body lumen may be suctioned thereby decreasing a distance between the target tissue and the other tissue. The body lumen may be ventilated thereby decreasing a distance between the target tissue and the other tissue. A midportion of the traction band may be coupled to a third tissue. The traction band may be released from the other tissue. 
     All of the devices and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the devices and methods of this disclosure have been described in terms of preferred embodiments, it may be apparent to those of skill in the art that variations can be applied to the devices and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the disclosure. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the disclosure as defined by the appended claims.