US20140275769A1 - Apparatus for tissue dissection with suction ring - Google Patents

Abstract

A medical device may include a housing. The housing may include an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall. The distal end of the outer wall may be disposed proximally from the distal end of the inner wall. The housing may further define a passageway therethrough. The cavity may be in fluid communication with a port configured to adjust pressure within the cavity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of priority from U.S. Provisional Application No. 61/777,988, filed on Mar. 12, 2013, and U.S. Provisional Application No. 61/798,690, filed on Mar. 15, 2013, each of which is incorporated by reference herein in its entirety.
DESCRIPTION OF THE INVENTION
• 1. Field of the Disclosure
• The present disclosure generally relates to a medical instrument, and more particularly to an apparatus for tissue resection.
• 2. Background
• A wide variety of medical techniques and instruments have been developed for diagnosis and/or treatment within a patient's body, such as the gastrointestinal (GI) tract. For example, endoscopic mucosal resection (EMR) is a minimally invasive technique used for removing, e.g., malignant/non-malignant lesions and/or otherwise unwanted tissue. Endoscopic medical procedures, for example EMR, may excise sessile adenomas (i.e., tumors attached to a bodily surface) in an anatomical lumen. Such procedures often require the dissection of one tissue plane while leaving an underlying tissue plane intact. When performing these procedures, it is desirable to cleanly cut and retrieve a uniform tissue sample of sufficient size, particularly where a pathology study of the sample might be necessary. In addition, it is desirable for the resection to leave clean margins at the treatment site in order to minimize any further disruption of the surrounding anatomy.
• If the adenoma is flat against a lumen wall, however, excising the adenoma can be difficult. In such cases, one of several techniques may be used to raise the flat adenoma so that it may be excised appropriately without harming underlying tissue layers. For instance, forceps can be used to raise the flat adenoma. Also, injections of a solution into, e.g., the submucosal or an underlying tissue layer can create a space or opening under the tissue, creating a buffer zone. The space lifts the flat adenoma above the underlying tissue to facilitate removal, and minimizes mechanical or electrocautery damage to the deeper tissue layers.
• These conventional techniques and instruments, however, have many disadvantages and/or limitations. For example, perforation is a key concern as it poses a serious safety risk the patient. The present disclosure is described to overcome one or more of the above limitations and/or other shortcomings in the art.
SUMMARY OF THE DISCLOSURE
• The present disclosure relates to a embodiments of apparatus and methods for tissue resection, which may reduce the risk of perforating underlying tissue layers by, e.g., lifting and separating the mucosa from the muscularis, around the perimeter of the lesion or other unwanted tissue.
• In one embodiment, a medical device may include a housing. The housing may include an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall. The distal end of the outer wall may be disposed proximally from the distal end of the inner wall. The housing may further define a passageway therethrough. The cavity may be in fluid communication with a port configured to adjust pressure within the cavity.
• In another embodiment, an endoscopic mucosal resection device may include an elongate member. The elongate member may include a proximal end, a distal end, and a lumen extending therebetween. The device may also include a housing operably coupled and movable relative to the distal end of the elongate member. The housing may include an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall. The distal end of the outer wall may be disposed proximally from the distal end of the inner wall. The housing may further define a passageway therethrough. A proximal portion of the passageway may be configured to receive the elongate member therein. The device may also include a cutting device.
• In a further embodiment, a method of resecting tissue from within a patient may include advancing an endoscopic mucosal resection device to a target location within the patient. The endoscopic mucosal resection device may include a housing operably coupled and movable relative to the distal end of an elongate member. The housing may include an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall. The housing may further define a passageway therethrough. A proximal portion of the passageway may be configured to receive the elongate member therein. The method may also include disposing a distal end of the housing adjacent a tissue wall. The method may also include applying suction to the cavity to draw at least one layer of the tissue wall into the cavity. The method may also include resecting a portion of tissue drawn into the cavity.
• Other aspects and features of the disclosure will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present disclosure is further described in the detailed description which follows, in reference to the drawings, by way of non-limiting examples of preferred embodiments of the present disclosure, in which like characters represent like elements throughout the several views of the drawings.
• FIG. 1 illustrates a perspective view of an exemplary tissue resection apparatus according to an embodiment of the present disclosure.
• FIG. 2 is a cross-sectional view of the exemplary tissue resection apparatus ofFIG. 1.
• FIG. 3 is a cross-sectional view of the exemplary tissue resection apparatus including an endoscope therein and in cooperating with tissue, according to an embodiment of the present disclosure.
• FIG. 4 is a schematic view of an exemplary tissue resection apparatus in combination with a suitable cutting device, in accordance with another embodiment of the present disclosure.
• FIG. 5 is a cross-sectional view of an exemplary tissue resecting apparatus, according to a further aspect of the present disclosure.
• FIG. 6A is a top view of the apparatus ofFIG. 5.
• FIG. 6B is a bottom view of the apparatus ofFIG. 5.
• FIGS. 7A-7B depict an alternate embodiment of an apparatus in accordance with a further embodiment of the present disclosure.
• FIG. 8 depicts a further embodiment of an apparatus in accordance with the present disclosure.
• FIGS. 9A-9C depict exemplary structures to facilitate separating a first tissue layer from a second tissue layer, in accordance with the present disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
• Reference will now be made in detail to the exemplary embodiments of the disclosure illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
• The present disclosure relates to an apparatus for endoscopic treatment, which may reduce the risk of perforating an underlying tissue layer, e.g., by lifting and separating the tissue layer intended for resection from the underlying layer, which is not intended for the resection.FIG. 1 andFIG. 2 illustrate an exemplary tissue resection apparatus1, according to an embodiment of the present disclosure. As shown, the apparatus may include ahousing3 having anouter wall5 and aninner wall7 disposed within thehousing3. Theinner wall7 is surrounded by theouter wall5 and separated by a specific distance so that there is acavity11 or a hollow gap (referred hereinafter as the “cavity”) formed between theouter wall5 and theinner wall7. In one embodiment, thecavity11 may be substantially annular or completely annular, extending completely aboutchamber13. The distal end of thehousing3 is opened so that thehousing3 is adapted to be placed against a surface of tissue. Thehousing3 further includes a connection to a suction source, for example theport9, for applying suction in thecavity11 to draw tissue into thecavity11.
• In some embodiments, the space surrounded by theinner wall7 may be hollow, forming ahollow chamber13, as depicted inFIG. 2. As will be described in further detail below, thehousing3 may include aproximal opening15, providing access to thehollow chamber13, so that an elongated tubular member (not shown inFIG. 2) can be inserted into thehollow chamber13.
• FIG. 3 illustrates a cross-sectional view of the apparatus1 being placed against a tissue layer “L”. When the apparatus is placed against the surface of targeted tissue layer “L”, the suction applied from the suction source (not shown) via theport9 draws in the targeted tissue “L” into thecavity11, thereby forming a ridge of tissue, as illustrated inFIG. 3. In one embodiment,port9 may be in fluid communication withcavity11, so that a vacuum applied toportion9 may be realized throughoutcavity11. As shown inFIG. 1, e.g.,port9 may be offset relative to a longitudinal axis ofhousing3 such that cavity13 (discussed below) may receivetubular member17 therein. A portion ofport9 may be configured to extend away from a proximal end ofhousing3. The raised ridge of tissue drawn into thecavity11 may facilitate snaring or other resection methods. Thecavity11 may be preferably narrow so that the non-targeted sub tissue layer (e.g., tissue layer “SL”) is excluded from being drawn up into the cavity, thereby reducing the risk of perforating the SL tissue layer.
• In some embodiments, thehousing3 may include a substantially cylindrical shape. In such a case, a continuous circular cavity will be formed between theouter wall5 and theinner wall7, and the tissue drawn into thecavity11 will form a circumferential ridge of tissue surrounding a substantially flat tissue surface in the middle, as illustrated inFIG. 3. However, it should be noted that thehousing3 can be in any shape suitable for forming thecavity11 for drawing tissue therein. For example,housing3 may include a square or rectangular configuration shown in, e.g.,FIGS. 7A,7B, and8. More particularly,housing3 defines an opening having at least one straight edge to facilitate removal of tissue via a tessellation technique.
• As briefly described above, the apparatus1 may include ahollow chamber13 for accommodating an elongated tubular member (e.g., tubular member17). In an aspect, the apparatus1 may be configured as an endoscopic cap, and theelongated tubular member17 may be an endoscope with various endoscope functionalities, including visualization, illumination, flushing, irrigation, suction, and the like, and using a variety of tools through its working channels (not shown). Those of ordinary skill in the art will understand thattubular member17 may include any suitable introduction sheath known in the art.
• In some embodiments, one or more internal working channels may be included inside thetubular member17 for receiving endoscopic instruments, such as an optical scope or as an aspiration path connected to the suction source. It should be noted that the internal working channels may have non-circular cross-sectional shapes, and may be in any shapes depending on the types of endoscopic instrument and/or application of the working channel(s). Further, thetubular member17 may include a number of additional lumens for receiving control wires, which may extend from various control sources (e.g., actuation handle, knobs, steering controls, etc.) disposed at the proximal end oftubular member17 through thetubular member17.
• An external shape and dimension of thetubular member17 may be substantially the same as thehollow chamber13. In some embodiments, the dimension (e.g., width) of thetubular member17 may be slightly larger than the size of thehollow chamber13 in order to facilitate a tight fitting of thetubular member17 into thehollow chamber13. In such cases, the surroundings of the proximal opening of thehollow chamber13 and/or theinner wall7 may be made of a flexible material that is elastically deformable to accommodate the largertubular member17 into thehollow chamber13. In some embodiments, thetubular member17 may be made of a flexible material that is elastically deformable, so that thetubular member15 can be snuggly fitted into thehollow chamber13. In addition, one or more ledges orridges19 may be formed on an interior wall of thehollow chamber13 to prevent thetubular member17 from passing through the entirehollow chamber13. A position of ledges orridges19 alonginner wall7 may be varied as desired to alter a position oftubular member17 relative tohousing3. Also, in some other embodiments, the apparatus1 may be configured so that theelongated tubular member17 can pass completely through thehollow chamber13, which will allow for extension and retraction of the apparatus1 relative to the tubular member17 (e.g., endoscope). In such embodiments, therefore, ledges orridges19 may be excluded.
• FIG. 4 illustrates an exemplary embodiment of the apparatus1 equipped with asnare21. Those of ordinary skill in the art will understand that any suitable cutting device may be used in conjunction with apparatus1. As shown, snare21 can be opened and preloaded around the exterior of the apparatus1 prior to drawing in the tissue. When the tissue layer (“L”) is drawn into thecavity11 as shown inFIG. 2, thesnare21 can be closed around the base of the raised circumferential ridge of the drawn up tissue for resection. In this example, thetubular member17 may be surrounded by asheath23, which may contain at least oneauxiliary working channel25. Thesheath23 may include a flexible tubular member extending proximally away from a proximal end of thehousing3. Auxiliary workingchannel25 may include a lumen in theaforementioned sheath23 or another tubular member operably coupled to thesheath23. For instance, theauxiliary working channel25 may accommodate thesnare21. It should be appreciated that thesheath23 may include a plurality of auxiliary workingchannels25 for various other functionalities. For example, one of the working channels may function as the aspiration path between theport9 and the suction source (not shown). Additional auxiliary working channels may be included in thesheath23 to accommodate various other instruments and functionalities. Although the apparatus1 and thetubular member17 have been described in the context of an endoscope cap with a snare, it is contemplated that thetubular member17 also may be any other medical device, such as a catheter or guiding tube that includes any number of the features and characteristics disclosed herein. Further, various tissue dissection/resection tools may be also used in conjunction with the apparatus1 for tissue resection or other endoscopic treatment.
• FIG. 5 illustrates additional details of the apparatus1. The distal end portion of theouter wall5 may be rounded and bent towards theinner wall7 at a predetermined angle. This angle may promote drawing in the tissue positioned underneath the hollow chamber13 (i.e., the tissue layer “L” surrounded by the most distal end/tip27 of the inner wall7) so that tissue underneath thehollow chamber13 becomes taut as illustrated by the arrows inFIG. 3.
• In some embodiments, the distal most end/tip27 of theinner wall7 is substantially co-planar with the distal most end/tip29 of theouter wall5. In other embodiments, however, thetip27 of theinner wall7 may be recessed towards the proximal end of thehousing3 relative to thetip29 of theouter wall5 as shown inFIG. 5. In other words, thetip29 of theouter wall5 is extended closer to the surface of the tissue layer (“L”) than thetip27 of theinner wall7. In this configuration, thehollow chamber13 may not be completely isolated from the suction applied via theport9 by theinner wall7. Accordingly, when the suction is applied from the suction source, the tissue layer (“L”) enclosed within thetip29 of theouter wall5 may be drawn up (i.e., lifted) to the level of thetip27 of theinner wall7 initially. When the tissue layer (“L”) contacts thetip27 of the recessedinner wall7, a seal may be formed so that thecavity11 is isolated from thehollow chamber13. In other words, the recessedinner wall7 elevates the tissue layer (“L”) approximately equal to the vertical distance (“D1” shown inFIG. 5) between thetip29 of theouter wall5 and thetip27 of theinner wall7.
• Once the tissue layer “L”, which is enclosed within thehousing3, is elevated and thehollow chamber13 is isolated from the suction applied via theport9, the tissue layer “L” may be further drawn into thecavity11 to form a ridge of tissue surrounding the substantially flat tissue underneath thehollow chamber13. It is contemplated that the elevation of tissue within thehousing3 can prevent thesnare21 from snagging on theinner wall7 during resection procedure, e.g.
• Further, in some embodiments, adistal tip27 ofinner wall7 may be longer thantip29 ofouter wall5. For example, with reference toFIG. 8,apparatus80 may include anouter wall82 and aninner wall84.Inner wall84 may be configured to extend distally further thanouter wall82 to ensure proper suction on the targeted tissue is maintained. In other embodiments, however, the distal ends of both inner andouter walls82 and84 may be flush with one another.
• In some embodiments, thehollow chamber13 may be provided with itsown aspiration port31 to provide negative/positive pressure in thehollow chamber13. For example, negative pressure may be applied to draw tissue into the disclosed apparatus. In the embodiments where positive pressure is applied, the positive pressure may be used to expel tissue lodged in the disclosed apparatus or otherwise in contact with the disclosed apparatus. In such embodiments, atubular member15 may include an internal or an auxiliary working channel (not shown) providing an aspiration path for thehollow chamber13. In some embodiments, one or both ofports9 and31 may be used to introduce, e.g., irrigation or insufflation, to a location within a patient's body.
• In some embodiments, the length of the inner wall7 (e.g., the vertical length “D2”) may be adjustable, such that thetip27 of theinner wall7 may be extended and/or retracted in distal and proximal directions relative towall5. It is contemplated that the adjustableinner wall7 enables controlling the amount of elevation of the tissue required for creating the seal (e.g., isolating thehollow chamber13 from the port9), at which point the tissue will be drawn into thecavity11 to form the ridge of tissue. Adjustinginner wall7 may also allow sufficiently separating tissue layers so that an underlying tissue is not perforated during a resection procedure. When it is not necessary to elevate the tissue prior to forming the ridge of tissue, theinner wall7 may be extended in the distal direction so that thetip27 of theinner wall7 is substantially co-planar with thetip29 of theouter wall5, thereby creating instant isolation of thehollow chamber13 from the suction applied via theport9. Those of ordinary skill in the art will readily recognize thatouter wall5 may be also configured to be adjustable in substantially the same manner asinner wall7.
• Various types of mechanisms and configurations may be employed in implementing the adjustableinner wall7 orouter wall5. For the purposes of efficiency, the adjustable mechanisms will be only described relative toinner wall7, however those of ordinary skill will understand that the same principles may be applied toouter wall5. In an exemplary embodiment, theinner wall7 may include a plurality oftelescoping segments33 that are arranged to slide, e.g., in and out relative to one another, as depicted inFIG. 5. In this example, theelongated tubular member15 may be used in exerting the force necessary for extending and/or retracting thetelescoping segments33. For instance, theelongated member15 may include one or more grooves that may selectively couple with one or more ofridges19 or may abut a fixed portion of theinner wall7, such that the vertical length (“D2”) of theinner wall7 may be controlled by pushing in and/or pulling out thetubular member15. In some other embodiments, some portion of theinner wall7 may be formed as a screw thread, a helical ridge, a spiral groove and/or appropriate gearing mechanisms, such that the distance between thetip27 of theinner wall7 and thetip29 of theouter wall5 is adjusted by applying rotational force to move theinner wall7 in the proximal or distal directions relative toouter wall5. For example, a portion of an external wall of theelongated tubular member15 may include a screw thread corresponding to a screw thread on theinner wall7, so that rotational force applied to thetubular member15 facilitates moving theinner wall7 relativeouter wall5. In some other embodiments, other control means that are operable via the working channel and/or the lumen may be used in implementing the adjustableinner wall7. Such other control means may include, e.g., an electric motor disposed in thehousing3 or thetubular member15 controlled via the control lines extending through the lumen in thetubular member15.
• The size (e.g., a width or volume) of the resected tissue may be controlled by the amount of tissue drawn into thecavity11. Accordingly, in some embodiments, the apparatus1 may further include a number ofdepth limiters35 disposed within thecavity11 to adjust and/or control the amount of tissue drawn into thecavity11, as shown inFIGS. 5,6A and6B. The depth limiters35 may include a plurality of blocks, panels, or other suitable structures that extend between theouter wall5 and theinner wall7 at a specific depth (e.g., “D3” shown inFIG. 5) within and around thecavity11. The plurality ofdepth limiters35 may be arranged relative to each other in such a way that a plurality ofgaps37 is formed between every twoadjacent depth limiters35. The size of eachgap37 formed between thedepth limiters35 should be sufficient to maintain the air-flow necessary for drawing tissue into thecavity11 while preventing the tissue from passing through thegap37. The size of thegaps37 formed between each of thedepth limiters35 may vary depending on the type of tissues and/or the type of resection procedures.
• In some embodiments, the depth of the vertical distance (“D3”) of the depth limiters relative to thetip29 of theouter wall5 may be adjustable. By way of an example, some portion of theinner wall7 may include one or more slots for receiving thedepth limiters35, so that thedepth limiter35 can be moved distally or proximally within thecavity11. Similarly, the depth limiters may extend from or be received in an inner surface ofouter wall5. One of the internal or the auxiliary working channels may be used for extending a control mechanism for movingdepth limiters35 within thecavity11. The control mechanism may be a rotatable rod or a cable configured to push and pull thedepth limiters35 along thecavity11. In some other embodiments, thedepth limiters35 may utilize a screw thread, a helical ridge, a spiral grove and/or other suitable mechanisms configured for adjusting the position ofdepth limiters35. The control mechanism may also be an electrical motor disposed in thehousing3 or thetubular member15, providing sufficient force to move thedepth limiters35 as desired.
• Further, the plurality ofdepth limiters35 may be formed as a single piece structure in order to simplify the control mechanism for adjusting thedepth limiter35. Alternatively, eachdepth limiter35 may be separately adjustable by providing an independent control mechanism for eachdepth limiter35. This configuration may allow for more precise control over the amount of tissue being drawn into thecavity11 as each of thedepth limiters35 around thecavity11 may be adjusted to be at differing depths. It should be appreciated that various other control mechanisms and configurations may be used in implementing theadjustable depth limiters35.
• In some embodiments, the disclosed apparatus may include suitable cutting and/or ligating instruments. For example, as shown inFIG. 7B, thedevice70 may be provided with acutting tool72 disposed about a periphery ofopening74. Cuttingtool72 may include any suitable tool known in the art. For example, in one embodiment, cuttingtool72 may include a snare, which may or may not include electro-cautery capabilities. Further, cuttingtool72 may include a ligating band or shuttling wire in some embodiments. Further, although the depicted embodiment illustrates that cuttingtool72 is disposed adjacentouter wall76, those of ordinary skill in the art will understand that cuttingtool72 may be disposed adjacentinner wall78.
• FIGS. 9A-9C depict embodiments of an alternative apparatus in accordance with the present disclosure. For example, as shown inFIG. 9A,inner wall90 may be longer thanouter wall94. Togetherinner wall90 andouter wall94 may define agroove96 therebetween for receiving tissue. A cutting tool98 (as discussed above) may be disposed adjacentouter wall94. A distal end ofinner wall90 may be angled away fromouter wall94. Further, an outer, distal edge ofouter wall94 may include a bevel or chamfer.Groove96 may include a generally rectangular cross-sectional configuration.
• With reference toFIG. 9B, e.g., a distal end ofinner wall90 may be substantially planar. However,outer wall94 may include a configuration that anglesouter wall94 towardinner wall90. Turning now toFIG. 9C,inner wall96 may include afirst portion96amovably coupled to asecond portion96b.First portion96amay be configured to move reciprocally in the directions ofarrow100.Second portion96bmay be configured to transition between a first configuration and a second configuration, wherein in the second configuration, thesecond portion96bis configured to trap tissue betweensecond portion96band an inner surface ofouter wall94.
• It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, length, and arrangement of components without exceeding the scope of the present disclosure. Thus, the present disclosure is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the present disclosure as defined by the claims.

Claims (20)

What is claimed is:

1. A medical device, comprising:

a housing including an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall, wherein the distal end of the outer wall is disposed proximally from the distal end of the inner wall, the housing further defines a passageway therethrough, and the cavity is in fluid communication with a port configured to adjust pressure within the cavity.

2. The medical device ofclaim 1, further comprising a plurality a depth limiters disposed in the cavity, wherein the plurality of depth limiters extend from one of the inner or outer walls.

3. The medical device ofclaim 1, further comprising an element capable of resecting tissue provided external to the inner wall.

4. The medical device ofclaim 3, wherein the element capable of resecting tissue is a snare.

5. The medical device ofclaim 1, wherein the inner wall includes at least one ledge projecting into the passageway for limiting a travel of the elongate member.

6. The medical device ofclaim 1, wherein the housing defines an opening having at least one straight edge.

7. The medical device ofclaim 8, wherein the housing defines an opening having a plurality of straight edges.

8. The medical device ofclaim 1, wherein the inner wall is adjustable relative to the outer wall.

9. The medical device ofclaim 1, wherein the elongate member includes an endoscope including at least one imaging device.

10. The medical device ofclaim 1, wherein the housing includes a sheath extending proximally therefrom, and wherein the sheath includes a lumen configured to receive an endoscopic cutting device.

11. The medical device ofclaim 1, wherein a distal end of the outer wall is curved towards the inner wall.

12. An endoscopic mucosal resection device, comprising:

an elongate member including a proximal end, a distal end, and a lumen extending therebetween;

a housing operably coupled and movable relative to the distal end of the elongate member, the housing including an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall, wherein the distal end of the outer wall is disposed proximally from the distal end of the inner wall, the housing further defines a passageway therethrough, and a proximal portion of the passageway is configured to receive the elongate member therein; and

a cutting device.

13. The medical device ofclaim 12, wherein the cavity is in fluid communication with a port configured to adjust pressure within the cavity.

14. The medical device ofclaim 12, wherein the cutting device is provided external to the inner wall.

15. The medical device ofclaim 12, wherein the inner wall includes at least one ledge projecting into the passageway for limiting travel of the elongate member.

16. The medical device ofclaim 12, wherein the inner wall is adjustable relative to the outer wall.

17. The medical device ofclaim 12, further including at least one depth limiter disposed in the cavity and extending from one of the inner or outer walls.

18. The medical device ofclaim 12, wherein the housing includes a sheath extending proximally therefrom, the sheath including a lumen for receiving a portion of the cutting device.

19. A method of resecting tissue from within a patient, comprising:

advancing an endoscopic mucosal resection device to a target location within the patient, the endoscopic mucosal resection device comprising:

a housing operably coupled and movable relative to the distal end of an elongate member, the housing including an outer wall, an inner wall spaced from the outer wall, and a cavity defined by the outer wall and the inner wall, wherein the housing further defines a passageway therethrough, a proximal portion of the passageway being configured to receive the elongate member therein;

disposing a distal end of the housing adjacent a tissue wall;

applying suction to the cavity to draw at least one layer of the tissue wall into the cavity; and

resecting a portion of tissue drawn into the cavity.

20. The method ofclaim 19, wherein a distal end of the outer wall is disposed proximally of a distal end of the inner wall.

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