Patent Publication Number: US-2020275925-A1

Title: Systems, devices, and related methods for fastening tissue

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority from U.S. Provisional Application No. 62/812,538, filed Mar. 1, 2019, which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     Various aspects of the present disclosure relate generally to tissue fastening, including visualizing, retracting, and coupling tissue. More specifically, at least certain embodiments of the present disclosure relate to systems, devices, and related methods for stapling tissue, among other aspects. 
     BACKGROUND 
     Technological developments have given users of medical systems, devices, and methods, the ability to conduct increasingly complex procedures on subjects. The coupling of tissue in, for example, a subject&#39;s gastrointestinal tract, is a type of procedure in which difficulties may arise. Surgical devices that grasp or clamp tissue between opposing jaw structures and then join the tissue by surgical fasteners are known. The fasteners include surgical staples. In some procedures, a cutting instrument is provided to cut the tissue which has been joined by the fasteners. However, problems arise when stapling and cutting tissue in order to remove tumorous tissue from a patient&#39;s body. 
     One such difficulty involves removing a lesion from tissue. In order to remove a lesion, the user may staple tissue around the outer edge of the lesion. When a lesion is highly contagious, it is important to cut the tissue at a region that does not include the lesion to avoid spreading the contagious tissue. There is a need for stapler instruments that include both stapling and cutting features that address this difficulty. 
     Often surgical staplers include a staple cartridge to house a plurality of staples. An anvil defines a surface for forming the staple legs as the staples are driven from the staple cartridge. The stapling operation may be effected by an actuator acting upon a staple, which often involves pushing the actuator in a distal direction to drive the staples from the cartridge. With such a configuration, problems arise when pushing the actuator due to curves in portions of the stapler connecting its proximal and distal ends, and a user may find it difficult to actuate the stapler when the stapler is rotated or angled from a longitudinally straight position. 
     Another difficulty involves removing a lesion from tissue by stapling its outer perimeter and cutting the lesion from the tissue. In order to remove the lesion, the user may first staple tissue around the lesion. When stapling, the user may need to clearly observe the outer edge of the lesion, however the user&#39;s field of view may be obstructed by the stapler if the distal end of the stapler is longitudinal rigid or fixed, preventing the instrument from bending and moving out of the field of view of the user. For example, during an endoscopic procedure, the optics of the endoscope often are positioned immediately adjacent the tissue, resulting in poor recognition of the endoscope location relative to the rest of the body lumen or larger tumors. 
     SUMMARY 
     Aspects of the disclosure relate to, among other things, systems, devices, and methods for fastening tissue. Each of the aspects disclosed herein may include one or more of the features described in connection with any of the other disclosed aspects. 
     According to one aspect, a tissue fastening device may include a handle assembly including at least two actuators. The tissue fastening device may also include a first body extending distally from the handle assembly and defining a longitudinal axis. The tissue fastening device may also include a fastening device coupled to a distal end of the first body. The fastening device may include a longitudinal body including a channel, a cartridge configured to include a plurality of fasteners, a longitudinal channel configured to receive a device for cutting tissue, an anvil rotatable relative to the cartridge, and a fastener actuator. The fastener actuator may be coupled to one actuator of the at least two actuators and configured to move proximally relative to the cartridge to deploy the plurality of fasteners from the cartridge. 
     In other aspects of the disclosure, the tissue fastening device may include one or more of the features below. The tissue fastening device may include a protrusion extending from a side surface of the fastening device and defining a lumen configured to receive a tissue acquisition tool. The fastening device may include a device for cutting tissue. The fastener actuator may be coupled to an actuation wire that extends from the fastener actuator through the elongated body to the handle assembly, and the actuation wire may be coupled to a first actuator of the at least two actuators. The fastener actuator may be configured to move proximally relative to the cartridge and the anvil when the first actuator is actuated. A distal portion of the first body may include a rigid curved portion such that a longitudinal axis of the fastening device is transverse to a longitudinal axis of a proximal portion of the first body. The anvil may include a first recess, the longitudinal body may include a second recess opposing the first recess, and the first and second recesses may be configured to receive a tissue acquisition tool. The fastener actuator and the device for cutting tissue may be coupled to an actuation wire that extends from the fastening device through the first body to a first actuator of the handle assembly, and the first actuator may be configured to move both the fastener actuator and the device for cutting tissue proximally. The fastening device may be rotatably coupled to the first body. The fastener actuator may include a ramp, and a surface of the ramp that contacts the plurality of fasteners may have an angle of 30 degrees or less relative to a longitudinal axis of the longitudinal body. The fastening device may be fixedly coupled to the first body, and a longitudinal axis of the fastening device may be transverse to a longitudinal axis of the first body. 
     In other aspects, a tissue fastening device may include a handle assembly including at least two actuators. The tissue fastening device may also include a first body extending distally from the handle assembly and defining a longitudinal axis. The tissue fastening device may further include a fastening device coupled to a distal end of the first body. The fastening device may include a longitudinal body including a channel. The fastening device may also include a cartridge that includes a plurality of fasteners. The fastening device may further include an anvil mounted adjacent the cartridge. The tissue fastening device may also include a second body including a lumen. The first body may be positioned in, movable within, and extends from the lumen. The tissue fastening device may also include a coupler coupling a distal end of the second body to the fastening device. The fastening device may be pivotable about the coupler when the first body is moved proximally and/or distally. 
     In other aspects of this disclosure, the tissue fastening device may further include one or more of the features below. The second body may define an opening in a side wall of the second body and through which the first body extends. The second body may include a recess configured to receive a portion of the first body when the longitudinal axis of the fastening device is parallel to the longitudinal axis of the second body. The handle assembly may include a first actuator configured to move longitudinally in proximal and distal directions and a second actuator configured to pivot relative to a body of the handle assembly. 
     In other aspects of this disclosure, a system may include a tissue fastening device and a tissue acquisition tool moveably coupled to the tissue fastening device. The system may also include an oversheath including a distal end opening and at least two distal end portions. The oversheath may be positioned around the tissue fastening device and the tissue acquisition tool. The oversheath may be configured to move proximally and the at least two distal end portions may be configured to move radially outward, to expose the tissue fastening device and tissue acquisition tool. 
     In other aspects, the system may further include one or more of the features below. A longitudinal body including a channel and a guide protrusion. The guide protrusion may include a lumen configured to receive the tissue acquisition tool. The tissue fastening device may further include a cartridge including a plurality of fasteners; and an anvil mounted adjacent the cartridge. The tissue acquisition tool may be positioned within the lumen of the guide protrusion. A proximal portion of the oversheath may be positioned around an endoscope, and the endoscope may include an image sensor and at least two working channels. The at least two distal end portions may be biased radially inward and configured to partially enclose fastening device and tissue acquisition tool. 
     It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary aspects of the present disclosure and together with the description, serve to explain the principles of the disclosure. 
         FIG. 1  is a perspective view of an exemplary medical device, according to aspects of this disclosure. 
         FIG. 2  is a perspective view of an exemplary surgical system, according to aspects of this disclosure. 
         FIG. 3A  is a perspective view of an exemplary medical device, according to aspects of this disclosure, including a component being inserted into the device by a user. 
         FIG. 3B  is a perspective view of a portion of an exemplary medical device, according to aspects of this disclosure, with a component being inserted into the device by a user. 
         FIG. 4A  is a cross-sectional view of a portion of an exemplary medical device, according to aspects of the present disclosure. 
         FIG. 4B  is a side view of an exemplary actuation sled, according to aspects of the present disclosure. 
         FIGS. 5A and 5B  are perspective views of exemplary medical devices, according to aspects of this disclosure. 
         FIGS. 6A and 6B  are perspective views of exemplary medical devices, according to aspects of this disclosure. 
         FIGS. 7A and 7B  are perspective views of exemplary fields of view of an exemplary endoscopic system, according to aspects of this disclosure. 
         FIG. 8  is a perspective view of an exemplary surgical stapler system, according to aspects of this disclosure. 
         FIG. 9  is a perspective view of an exemplary surgical stapler system, according to aspects of this disclosure. 
         FIG. 10A  is a front view of an exemplary endoscope oversheath, according to aspects of this disclosure. 
         FIG. 10B  is a side perspective view of an exemplary endoscope oversheath, according to aspects of this disclosure. 
         FIG. 11  is a front view of an endoscope system including an endoscope oversheath, according to aspects of this disclosure. 
         FIG. 12  is a front view of an endoscope system including an endoscope oversheath, according to aspects of this disclosure. 
         FIG. 13  is a side perspective view of an exemplary endoscope oversheath, according to aspects of this disclosure. 
         FIG. 14  is another a side perspective view of an exemplary endoscope oversheath, according to aspects of this disclosure. 
         FIG. 15  is a side perspective view of an exemplary endoscope system including an oversheath shown in cross-section, according to aspects of the present disclosure. 
         FIG. 16  is a front view of the oversheath shown in  FIG. 15 , according to aspects of the present disclosure. 
         FIG. 17  is a perspective view of a surgical system including an endoscope and an exemplary medical device, according to aspects of the present disclosure. 
         FIG. 18  is a perspective view of the medical device shown in  FIG. 17 , according to aspects of the present disclosure. 
         FIG. 19  is a side view of the medical device shown in  FIG. 17 , according to aspects of the present disclosure. 
         FIGS. 20 and 21  are top views of the medical device shown in  FIG. 17 , according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is drawn to systems, devices, and methods for coupling, cutting, and resecting tissue, among other aspects. Reference will now be made in detail to aspects of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same or similar reference numbers will be used through the drawings to refer to the same or like parts. The term “distal” refers to a portion farthest away from a user when introducing a device into a patient. By contrast, the term “proximal” refers to a portion closest to the user when placing the device into the patient. The term “coupling tissue together” may refer, for example, to stapling, fixing, attaching, fastening, or otherwise joining two portions of tissue together. The term “fastener” may include staples, clips, elastic bands, suture, or any other fastener known in the art. As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not necessarily include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example,” rather than “ideal.” 
     Embodiments of the present disclosure may be used to visualize, cut, resect, and/or couple together target tissue in an endo-luminal space, or facilitate the process thereof. In particular, some embodiments combine a tissue resecting device with a tissue stapling device. The tissue stapling apparatus may include a resection or cutting mechanism (e.g., an integrated knife) and a stapling mechanism (stapler). The stapling apparatus may be delivered to target tissue through an endoscope working channel to the target tissue site. The overall system may include a retraction mechanism, such as a tissue clip, to pull tissue towards the tissue stapling device. All or parts of the tissue stapling device and the retraction mechanism could be metallic, plastic, or include a shape memory metal (such as nitinol), a shape memory polymer, a polymer, or any combination of materials. 
       FIG. 1  shows a surgical apparatus  100  in accordance with an embodiment of this disclosure. Apparatus  100  is a surgical stapling apparatus configured to engage body tissue, apply a plurality of surgical fasteners thereto, and form an incision in the fastened body tissue during minimally invasive surgical procedures, such as laparoscopic or endoscopic procedures. Apparatus  100  may be used to apply surgical clips or other fasteners, but will be primarily discussed in the context of applying staples from a staple cartridge positioned in a portion of the device&#39;s body, such as a loading unit. 
     As illustrated in  FIG. 1 , apparatus  100  includes a distal section  101  and a proximal section  102 . Surgical apparatus  100  also includes a handle assembly  103 , an elongate body  104 , and a stapler device  105 . The elongate body  104  may extend any length suitable for endoscopic or laparoscopic procedures, and may be configured to be positioned within a working channel of an endoscope. The elongate body  104  may be detachable from the handle assembly  103  to facilitate insertion of the elongate body  104  into a working channel of an endoscope or a channel of another device, for example by backloading body  104  into the working channel. In some examples, the elongate body may be flexible and/or may be rotatable about its axis. The elongate body  104  may include a lumen for positioning actuation wires within for actuating the stapler device  105  via the handle assembly  103  or actuating any other portion of the apparatus  100 . The elongate body  104  may be configured to receive a plurality of actuation wires or a single actuation wire (for example, actuation wire  118 ). In some examples, the elongate body  104  may be fixedly coupled to the stapler device  105 , and in other examples the elongate body  104  may be removably or releasably coupled to the stapler device  105 . 
     The handle assembly  103  may include a handle  106  and a body  115 . The handle  106  may include a fixed portion  107  and an actuator portion  108 . Fixed portion  107  of handle  106  may be fixedly coupled to body  115 , and fixed portion  107  may include a circular or oval portion or ring for positioning a user&#39;s fingers within, which may assist a user in holding the handle assembly  103 . In some examples, moveable portion  108  of handle  106  may be an actuator which may be pivotally coupled to body  115  and movable relative to the fixed portion  107  of handle  106 . Movable portion  108  may include a circular or oval portion for positioning a user&#39;s fingers within, which may assist in actuating surgical apparatus  100 . In some examples, movable portion  108  of handle  106  may be coupled to a proximal portion of an actuation wire, such as actuation wire  118 , via an adjustable coupler  116  and may be configured to actuate an anvil of stapler device  105  via actuation wire  118  extending between stapler device  105  and handle assembly  103 . In other examples, movable portion  108  of handle  106  may be configured to control any other mechanism of apparatus  100 , such as actuation of deploying staples from stapler device  105 . 
     In some examples, handle assembly  103  may include a moveable cover  112  pivotably coupled to housing  115  at pivot point  112   a . In  FIG. 1 , cover  112  is shown in an open position, exposing the internal portions of housing  115 . Cover  112  may be coupled to a proximal portion of housing  115  and may cover the internal components of handle assembly  103  when positioned longitudinally parallel to housing  115 , such that distalmost end  112   b  of cover  112  faces surface  115   b  of housing  115 . Cover  112  may be temporarily fixedly coupled to a position covering the internal components of housing  115  via a coupling mechanism at a distal portion of cover  112  and a distal portion of handle assembly  103 , such as a snap locking mechanism, in order to hold cover  112  in place and prevent movement of cover  112  relative to housing  115 . When held in place, cover  112  may form a pair of slots in housing  115  (not shown). When the distal portion of cover  112  is uncoupled from the distal portion of housing, a user may rotate (or pivot) cover  112  at pivot point  112   a  in order to have access to the internal components of handle assembly  103 . 
     Handle assembly  103  may further include a rotatable elongate connector  114  which may connect the elongate body  104  to handle assembly  103 . In some examples, rotatable elongate connector  114  may rotate relative to housing  115  to either tighten onto elongate body  104  in order to fixedly couple elongate body  104  to handle assembly  103 , or rotated to release elongate body  104  from handle assembly  103 . Within body  115 , one or more adjustable couplers  116 ,  119  may be positioned in longitudinal alignment with, or longitudinally parallel with, rotatable elongate connector  114  and may be configured to receive a portion of an actuation wire, such as actuation wire  118 . Any of adjustable couplers  116 ,  119  may be a vice which is moveable in order to clamp down onto an actuation wire and fixedly couple actuation wire to the adjustable coupler  116 ,  118 . In some examples, adjustable coupler  116 ,  119  may be moveable via a screw to adjust the coupler  116 ,  119  and couple or uncouple an actuation wire from coupler  116 ,  119 . 
     Adjustable coupler  119  may be coupled to longitudinal actuator  110  and moveable longitudinally via translating longitudinal actuator  110  within housing  115 . Longitudinal actuator  110  may be partially positioned within housing  115  and may be slidable longitudinally within two slots formed when cover  112  is positioned over the internal components of handle assembly  103 . Longitudinal actuator  110  may include a pair of opposing circular or oval portions or rings, with each circular portion defining an aperture for a user to position their fingers within. In some examples, longitudinal actuator  110  may be coupled to an actuation wire (not shown), such as via adjustable coupler  119  or via a different coupler within housing  115 , and may be configured to control staple deployment from stapler device  105 . In other examples, longitudinal actuator  110  may be configured to control any other mechanism of apparatus  100 , such as actuation of an anvil of stapler device  105 . 
     Distal section  101  of apparatus  100  includes a stapler device  105  coupled to a distal portion of elongate body  104 . A connector  125  of stapler device  105  may couple elongated body  104  to stapler device  105 . In some examples, connector  125  may be offset from a longitudinal axis of the body  121  of stapler device  105 . Body  121  of stapler device  105  may include a cartridge  122  positioned within a channel of body  121 . Cartridge  122  may be fixedly coupled to body  121  or may be removable from body  121 . In some examples, cartridge  122  may be integrally formed in body  121 . At a proximal portion of body  121 , an anvil  120  may be rotatably or pivotably coupled to body  121  at pivot axis  120   a , and may extend distally towards a distal end of stapler device  105 . In some examples, anvil  120  may be rotatably biased and may be biased to an open configuration, i.e. biased away from body  121  and cartridge  122  creating a space between the distal portion of anvil  120  and the distal portion of body  121  and cartridge  122 . Anvil  120  may be rotatable about axis  120   a  to contact body  121 , or pinch tissue between anvil  120  and body  121 , and provide a surface for which staples may be driven when ejected from cartridge  122 . 
     In some examples, body  121  may include a channel that supports cartridge  122 . Cartridge  122  may contain a plurality of surgical fasteners, such as staples, and the fasteners may be deployed from cartridge  122  when under the influence of a driving force exerted by an actuation sled, such as actuation sled  341  shown in  FIG. 3A . A plurality of spaced apart longitudinal slots  123  in cartridge  122  allow staples to pass through cartridge  122  and pierce tissue. In some examples, an actuation sled moves proximally in the longitudinal direction from a distal end of cartridge  122  and/or body  121  when actuated, contacting fasteners within cartridge  122  and pushing fasteners through longitudinal slots  123  in order to couple fasteners to tissue. In some examples, a single fastener may extend through each slot  123 . Each fastener may be partially within a slot  123  prior to deployment to assist with alignment of the fastener with the slot  123 . In some examples, two actuation sleds  341 ,  380  may be required to actuate two different longitudinal rows of fasteners in cartridge  122  (shown in  FIG. 3A ). 
     Cartridge  122  may also include an elongate longitudinal slot  124 . The elongate longitudinal slot  124  may be configured to receive and/or support a resecting tool, such as a knife blade (not shown). The elongate longitudinal slot  124  may be positioned on a side of cartridge  122  and may run longitudinally from the proximal end to the distal end of cartridge  122 . In some examples, each of the spaced apart longitudinal slots  123  may be positioned on one side of the elongate longitudinal slot  124 . Anvil  120  may include a groove (not shown) positioned longitudinally that may align with elongated longitudinal slot  124  when anvil  120  is in the closed position (i.e. anvil  120  is rotated such that a distal portion of anvil  120  comes into contact with body  121  and/or cartridge  122 , or pinches tissue between anvil  120  and body  121 ) and such groove may be configured to receive a resecting tool such as a knife or other sharp cutting tool within the elongate longitudinal slot  124 . The cutting tool may be actuated via an additional, separate actuation wire from the actuation wire that translated the actuation sled, or may be actuated via the same actuation wire as the actuation sled to translate both the actuation sled and the cutting tool at the same time. 
     A user may use apparatus  100  to couple one or more fasteners to tissue by first positioning tissue within the active region of stapler device  105 , or between body  121  and anvil  120 . Once tissue is positioned in the active region of stapler device  105 , a user may actuate the actuator portion  108  of handle  106 , which may then translate an actuation wire proximally and cause anvil  120  to close onto the tissue positioned within the stapler device&#39;s active region. While the user holds actuation portion  108  in an engaged position, thus maintaining the stapler device&#39;s clasp on the tissue, the user may pull proximally (or actuate) longitudinal actuator  110  to translate an actuation wire coupled to an actuation sled in the stapler device. When the actuation sled is translated proximally via the actuation wire coupled to the longitudinal actuator  110 , a ramp of the actuation sled may engage a fastener in cartridge  122  and push the fastener through a longitudinal slot  123  to pierce the tissue. When the fastener is deployed by the actuation sled, the fastener may subsequently engage anvil  120  and couple layers of tissue together. In some examples, the longitudinal actuator  110  may actuate an actuation wire coupled to both an actuation sled and a cutting tool, and may translate both the actuation sled and the cutting tool simultaneously to both pierce and fasten tissue with one or more fasteners and cut tissue. 
     In some examples, a user may backload elongate body  104  through the distal end of a working channel of an endoscope, through the body of the endoscope, and out of a proximal end of the endoscope prior to coupling the elongate body  104  to the handle assembly  103 . Once elongate body  104  is positioned within a working channel of an endoscope with stapler device  105  at the endoscope&#39;s distal end, a user may couple handle assembly  103  to elongate body  104  by inserting the proximal end of elongate body  104  into rotatable elongate connector  114 , and then rotating rotatable elongate connector  114  to fix elongate body  104  to handle assembly  103 . A user may then couple the proximal ends of actuation wires (such as actuation wire  118 ) positioned within elongate body to adjustable couplers  116 ,  119 . Once elongate body  104  is coupled to handle assembly  103  and actuation wires (such as actuation wire  118 ) are coupled to adjustable couplers  116 ,  119 , the user may close moveable cover  112  such that distalmost end  112   b  of cover  112  faces surface  115   b  of housing  115 . Cover  112  may be temporarily fixedly coupled to a position covering the internal components of housing  115  via a coupling mechanism at a distal portion of cover  112 , and a distal portion of handle assembly  103 , such as a snap locking mechanism, in order to hold cover  112  in place during use of apparatus  100 . 
       FIG. 2  shows a distal section of an endoscope  250 , a tissue acquisition tool  252  positioned within a working channel  256  of the endoscope  250 , and a surgical apparatus  200  positioned within another working channel  257  of the endoscope  250 , in accordance with an embodiment of this disclosure. Surgical apparatus  200  is substantially similar to surgical apparatus  100  and includes a stapler device  201  with longitudinal slots  223  for fastener deployment, an elongated longitudinal slot  224  for receiving a knife, and anvil  220 . Cartridge  225  is integrally formed in body  222  of stapler device  201 . A user may use a tissue acquisition tool  252  in combination with a stapler device, such as stapler device  201 , to facilitate grabbing tissue and positioning tissue in the active portion of stapler device  201 , i.e. between body  222  and anvil  220  for stapling. Tissue acquisition tool  252  may include an elongate body  253  extending longitudinally to a distal end portion  254 . In some examples, distal end portion  254  of tissue acquisition tool  252  may include a pair of rotatable jaws  256 ,  257  that are moveable between a closed configuration and an open configuration. A user may actuate jaws  256 ,  257  using an actuator present at the proximal portion of tissue acquisition tool  252  (not shown) to open and close jaws  256 ,  257  to facilitate grabbing and releasing tissue. A user may position tissue acquisition tool  252  within a working channel  256 , as shown in  FIG. 2 , separate from the working channel  257  in which the surgical apparatus  200  is positioned. In other examples, a user may position tissue acquisition tool  252  in the same working channel as surgical apparatus  200  (not shown) to facilitate positioning tissue between anvil  220  and body  222 . 
       FIG. 3A  shows a distal portion of an embodiment of surgical apparatus  300  including stapler device  301  that is configured to receive a removable cartridge  323 . When removable cartridge  323  is removed from body  321 , actuation sled  341  and knife  342  may be visible (shown in  FIG. 3A ). In some examples, when cartridge  323  is positioned within a channel  327  of body  321 , actuation sled  341  and knife  342  may be received within cartridge  323  and may not be visible. In other examples, actuation sled  341  and knife  342  may be received within cartridge  323  and may be visible when cartridge  323  is positioned within body  321 , such as by extending out of a channel in cartridge  323 . Actuation sled  341  and knife  342  may be coupled to a single actuation wire extending to a proximal portion of surgical apparatus  300  such that, when actuated, the actuation sled  341  and knife  342  move proximally in unison. In other examples, actuation sled  341  and knife  342  may be coupled to separate actuation wires extending from a proximal portion of either actuation sled  341  or knife  342  to a proximal portion of surgical apparatus  300 , such as to handle assembly  103  such that either the actuation sled  341  or the knife  342  may be actuated independently. Actuation sled  341  may be configured to be translated proximally to push fasteners, such as staples within cartridge  323 , out of slots  345  in cartridge to fasten tissue together. Actuation sled  341  and knife  342  may be pressed by the user into a distal pocket of cartridge  323  when cartridge  323  is first positioned within body  321 . 
     Actuation sled  341  may include a ramp  346  that is configured to engage, directly or indirectly, staples, or other fasteners from within cartridge  323  through slots  345 , to deploy fasteners to couple tissue. In some examples, ramp  346  may be angled at 45 degrees, 40 degrees, 35 degrees, 30 degrees, 25 degrees, or any other angle relative to a longitudinal axis of body  321 . Ramp  341  may be a shallow angle to require the actuation sled  341  to translate proximally for a longer distance in order to deploy fasteners in cartridge  323 . By providing actuation sled  341  with a shallow angle, long ramp  341 , a user may engage multiple fasteners at the same time when pulling actuation sled  341  proximally, and thus allowing, in some examples, multiple staples to deploy and pierce tissue at the same time. Furthermore, a shallow angle ramp  346 , e.g. an angle approximately 30 degrees or less, may prevent intermittent forces being applied to the actuator in the handle assembly due to the actuation sled  341  releasing from a fastener before engaging the next fastener, by continuously engaging fasteners in cartridge  323 , and thus may prevent errors during a procedure by providing a more continuous force applied to the actuator. In some examples, the ramp  346  of actuation sled  341  may engage two, three, four, or more fasteners in cartridge  323  at the same time. Since actuation sled  341  is pulled proximally to deploy fasteners, a user may generate higher loads when pulling a flexible wire, such as an actuation wire  118  shown in  FIG. 1 , compared to a pushing mechanism to deploy fasteners. An actuation body  343  may extend proximally from a proximal portion of ramp  346 , and actuation sled  341  may be pulled from the actuation body  343  to deploy fasteners. For example, actuation body  343  may be coupled to an actuation wire that extends to a proximal portion of the surgical apparatus  300 . In some examples, apparatus  300  may include two actuation sleds  341  and two actuation bodies  343  coupled to the same actuation wire to engage and deploy two separate rows of fasteners in cartridge  323 . 
     Knife  342  may have a similar structure to actuation sled  341  and may include a hooked distal portion  344  that includes sharp edges for cutting tissue. Knife  342  may be configured to travel longitudinally within an elongated longitudinal slot of cartridge  323 . In some examples, a portion of knife  342  extends into a groove of anvil  320 , such as groove  370  shown in  FIG. 3B , and travels within the groove longitudinally from the distal end of anvil  320  to the proximal end when a user actuates knife  342 , thus translating knife  342  longitudinally across cartridge  323  to cut tissue. 
       FIG. 3B  shows a distal portion of an alternative embodiment of surgical apparatus  355  including stapler device  356  that is configured to receive a removable cartridge  363 . In stapler device  356 , body  361  includes a distal end with a distal front face  362  that encloses cartridge  363  within body  361  with only the top portion of cartridge  363 , or the portion of cartridge  363  opposing a bottom surface of anvil  360 , exposed. Distal front face  362  prevents the distal end of cartridge  363 , or in some examples an actuation sled and/or a knife, from contacting tissue when moving stapler device  356 . Anvil  360  includes a groove  370  within a surface opposing cartridge  363 , configured to receive a knife when anvil  360  is in a closed position. 
       FIG. 4A  shows an enlarged, cross-sectional view of an exemplary stapler device  401  including body  421 , anvil  420 , cartridge  423  with fasteners  445 , and actuation sled  441  with actuation body  443 . The stapler device  401  in  FIG. 4A  is shown deploying fasteners  445  onto tissue  449 . Actuation sled  441  engages pistons or spacers  451 , and the pistons or spacers  451  then engage the fasteners  445  to deploy the fasteners  445 . As shown in  FIG. 4A , actuation sled  441  engages the pistons or spacers  451  as actuation sled  441  moves in the proximal direction P. Each piston or spacer  451  may be configured to translate within cartridge  423  and may be sized to engage only one fastener. In other examples, each piston or spacer  451  may be sized to engage multiple fasteners, or one or more pistons or spacers  451  may be sized to engage multiple fasteners while one or more other pistons or spacers  451  may be sized to engage only one fastener. Actuation sled  441  may be configured to move each piston or spacer  451  in a direction transverse to the longitudinal axis of body  421 . For example, actuation sled  441  and actuation body  443  may be pulled proximally via an actuation wire, which may move ramp  442  (shown in  FIG. 4B ) into contact with one or more pistons or spacers  451  and push one or more pistons or spacers  451  to deploy one or more fasteners  445  from cartridge  423 . Each of the pistons or spacers  451  may have an upper surface that aligns and/or is flush with a portion of each respective fastener  445 . For example, each fastener  445  may be a staple and may include three substantially flat sections with the middle substantially flat section aligning with the top surface of each spacer  451 . Each piston or spacer  451  may be sufficiently rigid to move uniformly upward when the ramp  442  of actuation sled engages a corner of the piston or spacer  451 . In some examples, each piston or spacer  451  may be coupled to cartridge  423  such that movement along the longitudinal axis of cartridge  423 , or in the proximal P or distal D directions shown in  FIG. 4A , is prevented while allowing movement in a direction perpendicular to the longitudinal axis of cartridge  423 . The pistons or spacers  451  in cartridge  423  may prevent fasteners  445 , such as staples, from partially deploying and may avoid improper stapling caused by a distal portion of a staple moving upward when a proximal portion of the staple does not move. By providing spacers  451  with flat top surfaces that align with fasteners  445 , the ramp  442  of actuation sled  441  can move proximally and push each fastener  445  uniformly upward by engaging each spacer. 
       FIG. 4B  shows an exemplary actuation sled  441  including a ramp  442 , a width  475 , a height  477 , and an actuation body  443 . Ramp  442  may include a first proximal section  444  and a second distal section  446 . In some examples, the first proximal section  444  may have a different incline angle  473  than the incline angle  471  of the second distal section  446 . For example, the first proximal section  446  may have an incline angle of 30 degrees and the second distal section may have an incline angle of 20 degrees. By varying the slope of ramp  442 , actuation sled  441  may push spacers  451  with varying levels of pressure as it moves proximally. In other examples, the first proximal section  446  and the second distal section  446  may have the same incline angles  471 ,  473  or they may have any other angle between 0 and 90 degrees. In some examples, actuation sled  441  may have a length  475  of 0.50 inches and a height of 0.215 inches. Actuation body  443  may extend from the bottom of ramp  442  and, in some examples, may also extend the length  475  of the actuation sled  441 . In some examples, actuation body may be 0.008 inch diameter stainless steel wire. 
       FIG. 4B  shows a partial cross-sectional view of an exemplary actuation sled  441 , a portion of an anvil  420  including a recess  450  in the anvil&#39;s surface that faces cartridge  423 , a portion of a cartridge  423 , a fastener  445 , and tissue  449  positioned between cartridge  423  and anvil  420 . When actuation sled  441  is actuated, for example pulled from its proximal end  443  proximally via an actuation mechanism such as an actuator in handle assembly  103 , ramp  442  will engage fastener  445  and translate fastener towards tissue  449  to pierce tissue  449  as the actuation sled  441  moves in the proximal direction. In other examples, a pin may be positioned between fastener  445  and actuation sled  441 , and ramp  442  may engage the pin instead of fastener  445 , the pin forcing the fastener  445  towards tissue  449 . When fastener  445  is translated through tissue  449  via engagement with actuation sled  441 , portions of fastener  445  may be pushed towards each other via engagement with recess  450  and may cause fastener to clasp onto tissue  449 . 
       FIG. 5A  shows an exemplary stapler device  501  that is angled relative to the longitudinal axis  560  of endoscope  550  and radially displaced from the endoscope&#39;s longitudinal axis  560 . Elongate body  555  may include a distal end exposed from the endoscope, the distal end may be biased into a curved orientation (shown in  FIG. 5A ) such that the longitudinal axis  561  of the stapler device  501  intersects the longitudinal axis  560  of the endoscope  550  in which a portion of elongate body  555  is positioned within. In some examples, the angle formed between the longitudinal axis  561  of stapler device  501  and the longitudinal axis  560  of the endoscope  550  may be fifteen degrees, thirty degrees, forty-five degrees, sixty degrees, or any other angle. Alternatively, the distal end of body  555  may include links or other structure that causes the distal end to be in a rigid or substantially rigid configuration shown in  FIG. 5A .  FIG. 5B  shows an alternative view of stapler device  501  in which elongate body  555  has been rotated ninety degrees to position stapler device  501  such that the longitudinal axis  561  of stapler device  501  is angled away from the longitudinal axis  560  of endoscope  550 . Axis  562  shows an axis perpendicular to longitudinal axis  560 . By having an elongate body  555  that is rigidly curved or otherwise biased curved to angle the longitudinal axis  561  of stapler device  501  relative to the longitudinal axis  560  of endoscope  550 , the user&#39;s working space may be modified to allow for greater visualization, for example visualization through a camera positioned at the distal end of endoscope  550 . Other benefits of angling stapler device  501  relative to the longitudinal axis of endoscope  550  may include facilitating alignment with a tissue acquisition tool and aiding in positioning tissue between the anvil and the body of stapler device  501 . In some examples, elongated body  555  may be articulable to angle and radially offset stapler device  501 . Body may be articulated via articulation links activated at a proximal end of endoscope  550 . 
       FIGS. 6A and 6B  show an example of a center line  660  of a field of view of a camera at the distal end of endoscope  650 . In  FIG. 6A , the longitudinal axis  661  of stapler device  601  is parallel to the center line  660 , and thus stapler device  601  is positioned on a side of the field of view.  FIG. 6B  shows stapler device  601  angled relative to the center line  660  of a field of view of a camera. In  FIG. 6B , by pushing stapler device  601  distally and articulating the elongate body attached to it, the longitudinal axis  661  intersects with the center line  660  and positions the distal end portion of stapler device  601  directly within the center of the field of view of the camera of endoscope  650 . 
       FIGS. 7A and 7B  show a field of view of a camera at a distal end of an endoscope in which a stapler device  701  and a tissue acquisition tool  754  are being utilized to manipulate and couple tissue  770 . Since stapler device  701  is angled relative to the longitudinal axis of the endoscope, the field of view includes a view of the space between the anvil and the body of stapler device  701 , facilitating the positioning of tissue  770  between the anvil and body for stapling. 
       FIG. 8  shows an example of an alternative embodiment of a stapler device  801  including a guide protrusion  840 . Guide protrusion  840  may include a lumen  842  configured to receive a tissue acquisition tool  844 . Tissue acquisition tool  844  may be positioned within lumen  842  of guide protrusion  840  prior to inserting endoscope  843  into a patient&#39;s body. Tool  844  and stapler device  801  can be backloaded into one or more lumens of endoscope  843 . Pre-aligning a tissue acquisition tool  844  within guide protrusion&#39;s lumen  842  may facilitate positioning tissue acquisition tool  844  within the space  846  between stapler device&#39;s  801  anvil and body (i.e. stapler device&#39;s active region), and may guide tissue acquisition tool  844  towards stapler device  801  when translated. Lumen  842  may be curved or otherwise angled towards stapler device  801  to bend tissue acquisition tool  844  towards stapler device  801 . For example, the plane of the distal opening of lumen  842  may be angled to face the stapler device&#39;s active region. Guide protrusion  840  may extend radially away from a portion of stapler device  801  that is proximal to stapler device&#39;s  801  anvil or space  846 . Guide protrusion  840  may be fixed to stapler device  801 . In some examples, guide protrusion  840  may be rigid or may be semi-rigid. Guide protrusion  840  may include a lumen  842  that includes a central longitudinal axis that is spaced from the longitudinal axis of stapler device  801 . 
       FIG. 9  shows an exemplary embodiment of a stapler device  901  including anvil  920 , body  922 , recess  946  in anvil  920 , and recess  947  in body  922 . Recesses  946 ,  947  may be positioned on radially inward facing surfaces of anvil  920  and body  922  respectively, opposing each other and may form a lumen between anvil  920  and body  922  when anvil  920  and body  922  are in a closed position that lumen traverses the longitudinal axis of stapler device  901 . A tissue acquisition tool  944  may be positioned within lumen recesses  946 ,  947  when stapler device  901  is in a closed position such that when elongated body  943  of tissue acquisition tool  944  is translated proximally, the distal end of tissue acquisition tool  944  is moved into the space between anvil  920  and body  922 . Pre-positioning tissue acquisition tool  944  within the space between anvil  920  and body  922 , or within the active portion of stapler device  901 , may allow a user to more easily position the distal end of tissue acquisition tool  944  and tissue within the active portion of stapler device  901 . Tissue acquisition tool  944  may be preloaded into the lumen formed by recesses  946 ,  947  prior to insertion into a patient&#39;s body. 
       FIGS. 10A and 10B  show front and side perspective views of an exemplary multi-lumen oversheath  1050  including shaft  1051 , distal end portion  1053 , lumens  1052 ,  1054 , and  1056 . Oversheath  1050  may provide a user with means for utilizing a tissue acquisition tool, a stapling device, and a steerable visualization tool, such as an endoscope that includes a camera.  FIG. 11  shows a front view of oversheath  1050  with an endoscope  1140  positioned within lumen  1052 . Since endoscope  1140  includes a single working channel  1142 , oversheath  1050  provides the user with three total working channels, i.e. lumens  1054 ,  1056  and working channel  1142 .  FIG. 12  shows another exemplary embodiment of an oversheath  1250  including two lumens  1252 ,  1254  with an endoscope  1240  positioned within lumen  1252 . Since endoscope  1240  includes a working channel  1242 , the oversheath  1250  provides an additional working channel (i.e. lumen  1254 ) for the user to utilize. Each of oversheath  1050  and  1250  may extend along the entire length of the endoscope  1140 ,  1240 . In other examples, oversheath  1050 ,  1250  may extend along only a portion of endoscope  1140 ,  1240 . For example,  FIGS. 13 and 14  show alternative embodiments of oversheaths  1350 ,  1450  with lumens  1352 ,  1354 ,  1356 ,  1452 ,  1456 . Oversheaths  1350 ,  1450  extend along only a portion of the distal end of an endoscope that they are positioned over, such as distal ends of endoscope  1340  or endoscope  1440  shown in  FIGS. 13 and 14 . Positioning either a stapler device or a tissue acquisition tool within a lumen of an oversheath may move the device or tool farther radially away from the center of the field of view of a camera at the distal end of an endoscope, and may provide a less obstructed view of target tissue the user seeks to position in the active region of the stapler. 
     In some examples, an oversheath may be used to protect the patient&#39;s tissue from unwanted contact with devices at the distal end of an endoscope while the endoscope travels through the patient&#39;s body.  FIG. 15  shows an exemplary oversheath  1552  positioned over an endoscope  1540 . Extending distally from the distal end of endoscope  1540  are stapler device  1501  and tissue acquisition tool  1543 , much like the devices shown in  FIG. 8 , though any tools may be used with oversheath  1552 . Oversheath  1552  is positioned over stapler device  1501  and tissue acquisition tool  1543 , and may prevent stapler device  1501  and tissue acquisition tool  1543  from contacting tissue and/or moving radially outward from the longitudinal axis of endoscope  1540 , as endoscope  1540  moves through a patient&#39;s body. An opening  1570  at the distal end of oversheath  1552  may provide the user with the ability to view in front of the endoscope  1540  while the endoscope  1540  and oversheath  1552  move through a patient&#39;s body. Opening  1570  may include one or more proximally extending slots  1570   a  ( 4  shown in  FIG. 16 ). Distal portions  1555 ,  1556  of oversheath  1552  may be movable and flexible to expand and contract opening  1570 . An exemplary expanded state of opening  1570  is shown as opening  1571  with dotted lines  1557 ,  1558  representing distal portions  1555 ,  1556  after having moved radially outward. Distal portions  1555 ,  1556  may move radially outwardly to form an expanded state in order to allow a user to access a target area with stapler device  1501  and tissue acquisition tool  1543 . To assist radially outward movement of distal portion  1555 ,  1556 , oversheath  1552  may include longitudinal slits  1567  that can be torn. For example, a tearable slit  1567  may extend from each of slots  1570   a  proximally a distance sufficient to allow separation of portions  1555 ,  1556  (e.g. to the distal face of endoscope  1540 ). In other examples, distal portions  1555 ,  1556  may be movable to allow the user to pull oversheath  1550  proximally and position stapler device  1501  and tissue acquisition tool  1543  within a target area. As shown in  FIG. 16 , oversheath  1550  may include four distal portions  1555 ,  1556 ,  1565 ,  1566  that may be moveable. In some examples, each of distal portions  1555 ,  1556 ,  1565 ,  1566  of oversheath  1550  may be configured to move proximally or distally relative to endoscope  1540  to allow a user to uncover or cover stapler device  1501  and tissue acquisition tool  1543 . In some examples, distal portions  1555 ,  1556 ,  1565 ,  1566  may move radially outward to expand opening  1570  in order to allow acquisition tool  1543  and stapler device  1501  to pass through opening  1570 . For example, distal portions  1555 ,  1556 ,  1565 ,  1566  may move radially outward when contacted by the stapler device  1501  and/or acquisition tool  1543  as the oversheath  1552  is translated proximally. In some examples, oversheath  1550  may be transparent/clear to allow a user to see through oversheath  1550  as endoscope  1540  moves through a patient&#39;s body. 
       FIG. 17  shows an exemplary medical apparatus  1700  including a stapler device  1701 , an elongate body  1704 , an elongate rod  1770  including a lumen  1772 , and a rotatable connector  1780 . The stapler device  1701  and elongate body  1704  may include any of the features and characteristics discussed hereinabove. Rod  1770  may be rigid and may be manufactured from polyether ether ketone (PEEK) or other suitable materials. Elongate body  1704  may be a non-compressible member, such as a Bowden cable, and may include a lumen (not shown) for receiving actuation wires and other components of stapler device  1701 . Lumen  1772  of rod  1770  may extend longitudinally from a proximal end to a distal portion of rod  1770 . In some examples, lumen  1772  may receive elongate body  1704  and may be configured to allow elongated body to move proximally and distally through lumen  1772 . Body  1704  may extend out of lumen  1772  via an opening  1779  in a side wall of rod  1770 . Rotatable connector  1780  may couple stapler device  1701  to rod  1770  and may be positioned between the proximal and distal ends of stapler device  1701 . In some examples, rotatable connector  1780  permits pivoting of stapler device  1701  relative to rod  1770  such that stapler device  1701  may move between a position where the longitudinal axis of stapler device  1701  is parallel with the longitudinal axis of rod  1770  and a position where the longitudinal axis of stapler device  1701  is transverse to the longitudinal axis of rod  1770 . In embodiments, rotatable connector  1780  may permit such pivoting so that the angle between the longitudinal axes is greater than zero degrees and up to as much as 180 degrees, where the longitudinal axis of stapler device  1701  is parallel with the longitudinal axis of rod  1770 .  FIGS. 18-21  show various views of medical apparatus  1700  with stapler device  1701  rotated various degrees relative to rod  1770 . As shown in  FIGS. 18 and 19 , lumen opening  1779  may be oval shaped and may be elongate in the longitudinal direction of rod  1770  to allow elongate body  1704  to smoothly transition into and out of rod  1770  and to minimize friction between lumen opening  1779  and elongate body  1704  when elongate body  1704  moves through lumen opening  1779 . A user may pivot stapler device  1701  by pushing or pulling on elongate body  1704  (to move elongated body  1704  proximally or distally), which then pushes or pulls on stapler device  1701  and causes stapler device  1701  to rotate about rotatable connector  1780 . In some embodiments, rotatable connector  1780  may include a pin extending through a device at a distal end of rod  1770  and a flange extending from stapler device  1701 . Stapler device  1701  may include a pair of flanges extending from a portion of its body that include apertures for a pin, and rod  1770  may include a device extending from a distal end of rod  1770  including an aperture that is configured to align with the apertures of the pair of flanges, and a pin may be positioned with the apertures of the pair of flanges and the aperture of the device extending from a distal end of rod  1770  to form rotatable connector  1780 . 
     Each of the aforementioned apparatuses and devices may be used to visualize, couple, and/or cut tissue. In some examples, a user may load an elongate body of a stapler device in a working channel of an endoscope by backfeeding the elongate body through a distal end of an endoscope working channel to position a portion of the elongate body within the working channel. Once the elongate body is positioned within a working channel, a handle assembly may be coupled to the proximal end of the elongate body. The user may then introduce the endoscope into the patient&#39;s body and move the endoscope towards a target area. The user may locate a target area (such as a tumor or other diseased tissue) present in a body lumen of a subject using the endoscope by directly visualizing the target area using an image sensor. Once the user has positioned the endoscope&#39;s distal end proximate to a target area, the user may position a tissue acquisition tool within a working channel of the endoscope, if such a tool is not already present. In some examples, if the user placed an oversheath over the endoscope prior to insertion of the endoscope into the patient&#39;s body, the user may move the oversheath proximally to expose the stapler device to the target area and/or tear away portions of the oversheath to expose the stapler device. When the distal end of the endoscope is positioned at the target area, the user may actuate the stapler device to an open position creating a space between the stapler&#39;s anvil and body. The user may then introduce the tissue acquisition tool to the target area and position the tissue acquisition tool between or close to the active portion of the stapler device, e.g. the space between the stapler device&#39;s anvil and body. The user may then grasp tissue with the tissue acquisition tool and move tissue into the stapler device&#39;s active portion. Once tissue is positioned within the stapler device&#39;s active portion, the user may move the stapler device&#39;s anvil and body to a closed position and clamp down on the grasped tissue with the stapler device. The user may then actuate an actuator in order to pull on an actuation wire, thus moving an actuation sled of the stapler device proximally. By moving the actuation sled proximally via an actuator, the user may deploy fasteners into the clamped tissue and against the stapler device&#39;s anvil. In some examples, the user may actuate a knife in the stapler device to cut portions of the target tissue either before or after fastening tissue together via fasteners. 
     By providing a stapler instrument that includes a flexible body while still able to effectively staple tissue, the user may be able to increase visualization of the target tissue and may prevent unwanted stapling errors, such as stapling within portions of contagious tissue. The increased visualization from a maneuverable, flexible stapler also may aid in ensuring that as much of or all of a target lesion is removed. 
     It will be apparent to those skilled in the art that various modifications and variations may be made in the disclosed devices and methods without departing from the scope of the disclosure. Other aspects of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the specification and examples be considered as exemplary only.