Abstract:
An endoscopic electrosurgical instrument is presented for encapsulating and resecting biologic tissue, such as a polyp, from an anatomical structure, such as a lumen. The instrument includes an encapsulation assembly which includes a snare coupled to an electrically non-conductive, shrinkable pouch in a drawstring-like configuration. The encapsulation assembly may be folded within the elongated cylindrical housing of the endoscopic instrument, positioned within the patient at the surgical site, and deployed for use. Once positioned over the polyp, the snare is tightened around the peduncle thereof, and the pouch is activated, thereby shrinking and encapsulating the polyp. The polyp may then be resected using conventional or electrosurgical techniques. The disclosed instrument may include surgical tools and/or electrosurgical electrodes for performing surgical procedures. The disclosed system may reduce the occurrence of undesirable arcing and may aid retrieval of resected tissue.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation application which claims the benefit of and priority to U.S. application Ser. No. 12/356,650, filed on Jan. 21, 2009, the entire contents of which are incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Disclosure 
         [0003]    The present disclosure relates to instruments for performing minimally invasive surgical procedures. More particularly, the present disclosure relates to an endoscopic electrosurgical instrument for encapsulating and resecting biologic tissue, such as a polyp, that includes a shrinkable pouch for isolating the tissue undergoing resection from the surrounding luminal walls or other adjacent tissue. 
         [0004]    2. Background of Related Art 
         [0005]    Minimally invasive surgical techniques have been developed wherein the surgical site is accessed by instruments inserted through small incisions in the body, as compared to traditional open surgical procedures where much larger incisions are required to expose the surgical site. Minimally invasive surgical procedures, also known generally as laparoscopic or endoscopic procedures, are often performed in conjunction with electrosurgical techniques. Throughout the present disclosure, the term “minimally invasive” should be understood to encompass both endoscopic and laparoscopic procedures, and the terms “minimally invasive”, “endoscopic”, and “laparoscopic” are to be construed equivalently. Minimally invasive surgical procedures are performed through access devices such as a cannula that is inserted percutaneously into a patient&#39;s body. The cannula has a central opening through which surgical objects are introduced and manipulated during the course of the procedure. 
         [0006]    Electrosurgical techniques employ radiofrequency (RF) electrical signals in the approximately 200 kHz-3.3 mHz range in connection with surgical instruments, to cut, ablate, or coagulate biologic tissue endogenically. Typically, electrosurgical signals are operated at 100% duty cycle for maximal cutting effect, and are pulse modulated at duty cycles ranging from 50% to 25% for less aggressive cutting, also referred to as blending, or, at a substantially lower duty cycle of approximately 6%, for coagulating. The electrosurgical signal can be applied to the patient via electrodes in either bipolar mode, or monopolar mode. In bipolar mode, both the active and return electrodes are at the surgical site, effectuated by, for example, both jaws of a pair of forceps, such that the electrosurgical signal passes through only the tissue that is held between the jaws of the instrument. In monopolar mode, the active electrode is the surgical instrument at the surgical site, and the return electrode is elsewhere on the patient, such that the electrosurgical signal passes through the patient&#39;s body from the surgical site to the return electrode. 
         [0007]    Snares are a class of surgical instruments used in the resection of tumors and polyps, particularly those situated on the inner walls of a lumen such as an esophagus, colon, intestine, urethra, blood vessel, or other tubular anatomic structure. Typically, the instrument has at its distal end a wire loop that is positioned around the base or peduncle of the polyp. A pouch or mesh basket for capturing the resected tissue may optionally be attached circumferentially to the wire loop. The proximal end of the instrument is coupled to a source of electrosurgical energy, such as an electrosurgical generator. After the snare is positioned, the surgeon actuates a control on the instrument which causes the wire loop to tighten around the polyp in a drawstring fashion. The surgeon then actuates a second control, typically a handswitch or footswitch, which causes electrosurgical energy to be applied through the wire loop to the operative site, which severs the polyp from the underlying tissue by electrosurgical cutting. 
         [0008]    Electrosurgical snares that perform the described technique may have drawbacks. For example, when a particularly large or irregularly shaped polyp is resected, uncontrolled arcing can occur between the polyp and the opposing lumen wall, between the polyp and another anatomical structure located near the polyp, or between the polyp and bodily fluids at the operative site. The uncontrolled dispersion of electrosurgical energy through arcing is undesirable, as it can cause the cutting operation to fail, can cause harmful burns to the opposing lumen wall or other anatomical structures, and can lead to increased operative times and impaired patient outcomes. 
       SUMMARY 
       [0009]    The present disclosure provides a wire loop snare that includes an electrically non-conductive shrinkable pouch attached thereto. The pouch encapsulates and electrically insulates the polyp being resected from surrounding tissue and/or bodily fluids. By insulating the polyp during the electrosurgical procedure, the uncontrolled dispersion of electrosurgical energy is prevented, thereby reducing the risk of arcing. Encapsulation of the polyp may also prevent the inadvertent spread of malignant or pathogenic cells from the polyp. 
         [0010]    The insulating shrinkable pouch may have several benefits. Bodily fluids which may remain trapped in the pouch may provide an undesirable return path for electrosurgical energy, which in turn may cause arcing. By shrinking the pouch around the polyp, voids and gaps which may exist between the polyp and pouch are collapsed, which causes bodily fluids in the pouch to be forced out, thereby eliminating a source of arcing and/or short-circuiting of the electrosurgical energy. Moreover, the shrinking pouch may reduce the size of the polyp and increase clearance between the polyp and surrounding tissue, which may also decrease the risk of arcing. Additionally, reducing the size of the polyp in accordance with the present disclosure can facilitate retrieval and removal of the polyp. It is envisioned the pouch may be constructed of any suitable shrinkable material now or in the future known, including without limitation heat-shrinkable material, electrically-shrinkable material, and/or chemically-shrinkable material. 
         [0011]    In accordance with the present disclosure, the wire loop snare is slidably affixed to the pouch circumferentially at its opening to enable the proximal ends of the wire loop to be pulled in a drawstring-like fashion, thus enabling the surgeon to tighten the snare around, for example, the base of a polyp. There is disposed at the pouch opening a generally tubular channel through which the wire loop snare passes. The wire loop is formed by a first wire and a second wire for providing activation current to the at least one activating element as will be further described below. The first and second wires are joined at their respective termini by an insulating member, located preferably at the distal end of the loop. The first and second wires are coupled to the at least one activating element at a location that is preferably substantially adjacent to the termini of the first and second wires, respectively. 
         [0012]    In one embodiment, the pouch is constructed of a heat-shrinkable material. Incorporated within the pouch material are activating elements for heating and thus shrinking the pouch. In an embodiment the activating elements are electrical conductors, constructed from resistance wire material such as Nichrome or other suitable resistance material. The activating elements are configured to form a heating array using, for example, a parallel, serial or series-parallel arrangement as will be familiar to a person of ordinary skill in the art. The heating array is coupled to the first and second wires, which are, in turn, switchably coupled, or electro-operably coupled, to a source of activating energy, such as an electric current that is controlled by, for example, a handswitch or a footswitch. The wires may be coupled to the heating array at a point substantially adjacent to the distal end of the wire loop snare, however, other coupling points are contemplated within the scope of the present disclosure. 
         [0013]    In another embodiment, the wire loop snare is an electrosurgical electrode for performing electrosurgical procedures such as cutting, blending and coagulation. The electrosurgical electrode wire is disposed along the edge of the pouch opening in an external drawstring configuration. The edge of the pouch is captured within a longitudinal slot formed by, for example, crimping the electrosurgical electrode around the edge of the pouch. First and second insulated conductor are provided on the outer surface of the electrode for activating the pouch heating array as previously described herein. 
         [0014]    In an alternative embodiment, a shrinkable mesh pouch having a deactivated (i.e., “unshrunken”) state and an activated (i.e., “shrunken”) state for capturing the polyp is disclosed. The mesh pouch can be constructed of a shape memory alloy, such as Nitinol, which is configured to shrink upon activation for reducing the size of the polyp. By compressing the polyp, the mesh pouch increases clearance between the polyp and surrounding tissue, decreasing the risk of arcing and aiding retrieval as well. 
         [0015]    The shrinkable wire mesh pouch can be configured by forming the wire mesh pouch from a suitable material, such as Nitinol mesh; annealing the pouch to define the austenite shape and size of the pouch corresponding to the activated state; and expanding the pouch to define the martensite size and shape corresponding to the deactivated state. The mesh pouch is initially provided to the surgical site in the martensite state. The mesh pouch is switchably coupled to a source of activating energy, such as an electric current that is controlled by, for example, a handswitch or a footswitch. The passage of electric current through the shape memory alloy material heats the material through its transformation temperature range, causing the pouch to revert to its austenite shape with significant force, thereby shrinking around, and encapsulating, the polyp. 
         [0016]    It is further envisioned that the shrinkable wire mesh incorporates a membrane for isolating the polyp from surrounding tissue. Optionally or additionally, the membrane can be formed from electrically insulating material. In an embodiment, the membrane is integrally disposed upon the outer surface of the wire mesh pouch to electrically and/or thermally insulate the wire mesh from surrounding tissue and/or bodily fluids. 
         [0017]    Also envisioned within the scope of the present disclosure is a surgical tool that is extendable from the instrument for performing additional or alternative treatment modalities at the operative site. In an embodiment, the surgical tool incorporates a cutting edge. Additionally or alternatively, the surgical tool is an electrosurgical electrode for performing electrosurgical cutting, blending and/or coagulating at the operative site. 
         [0018]    Also disclosed is a system for electrosurgical polyp resection and retrieval that includes an electrosurgical instrument coupled to a source of electrosurgical energy, such as an electrosurgical generator. The instrument consists of an elongated tubular support member that includes at its proximal end a handle and controls, such as a handswitch, for deploying and actuating the snare, for causing the pouch to be shrunk, and for activating electrosurgical energy. Additionally or alternatively, at least one footswitch control may be used for causing the pouch to be shrunk and/or activating electrosurgical energy. At its distal end, the tubular member houses a wire loop snare electrode that includes a shrinkable pouch attached thereto, wherein the wire loop electrode is configured to have an extended and a retracted position. The distal end of the tubular member optionally has an electrosurgical electrode having an extended and a retracted position for cutting, blending and/or coagulating tissue at the operative site. 
         [0019]    A method for encapsulating and resecting biologic tissue, such as a polyp, is disclosed that includes providing a wire loop snare having an electrically non-conducting, shrinkable pouch having an opening disposed circumferentially thereupon; positioning the snare over the polyp; tightening the snare around the base of the polyp in a drawstring fashion; shrinking the pouch to encapsulate and, optionally or alternatively, reduce the size of the polyp; providing an electrosurgical signal to the wire loop snare to sever the polyp from the underlying tissue; and withdrawing the pouch containing the resected tissue from the patient. The provided method can additionally include coagulating or cauterizing the operative site substantially concurrently with, or subsequent to, the step of severing the polyp. 
         [0020]    Yet another method for encapsulating and resecting biologic tissue, such as a polyp, is disclosed that includes providing a wire loop snare having a shrinkable mesh pouch having an opening disposed circumferentially thereupon; positioning the snare over the polyp; tightening the snare around the base of the polyp in a drawstring fashion; shrinking the pouch to capture and, optionally or alternatively, reduce the size of the polyp; providing an electrosurgical signal to the wire loop snare to sever the polyp from the underlying tissue; and withdrawing the mesh pouch containing the resected tissue from the patient. The aforesaid method can additionally include coagulating or cauterizing the operative site substantially concurrently with, or subsequent to, the step of severing the polyp. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    Various embodiments of the present disclosure will be described herein below with reference to the figures wherein: 
           [0022]      FIG. 1A  is a side cross sectional view of one embodiment of a polyp encapsulation snare in accordance with the present disclosure showing the undeployed snare folded within a cylindrical housing; 
           [0023]      FIG. 1B  is a side cross sectional view of the polyp encapsulation snare of  FIG. 1A  showing the snare in a deployed configuration; 
           [0024]      FIG. 2  is an oblique view of the polyp encapsulation snare of  FIG. 1B ; 
           [0025]      FIG. 3  is a side cross sectional view of another embodiment of a polyp encapsulation snare having an electrosurgical snare electrode in accordance with the present disclosure; 
           [0026]      FIG. 4  is an oblique view of the polyp encapsulation snare of  FIG. 3 ; 
           [0027]      FIG. 5A  is an axial cross sectional view of a polyp encapsulation snare in accordance with the present disclosure showing the wire loop drawstring attachment; 
           [0028]      FIG. 5B  is an oblique cross-sectional view of the wire loop drawstring attachment of  FIG. 5A ; 
           [0029]      FIG. 6A  is an axial cross sectional view of a polyp encapsulation snare in accordance with the present disclosure showing an electrosurgical electrode snare in an external drawstring arrangement; 
           [0030]      FIG. 6B  is an oblique cross sectional view of the external drawstring arrangement of the electrosurgical electrode snare of  FIG. 6A ; 
           [0031]      FIG. 7A  is an axial cross sectional view of a polyp encapsulation snare in accordance with the present disclosure showing an insulated conductor; 
           [0032]      FIG. 7B  is an oblique cross-sectional view of the wire an electrosurgical electrode snare of  FIG. 7A  showing the coupling of the insulated conductor to the heating array; 
           [0033]      FIG. 8A  is a side cross sectional view of still another embodiment of a polyp encapsulation snare in accordance with the present disclosure showing the surgical tool in a retracted configuration; 
           [0034]      FIG. 8B  is a side cross sectional view of the polyp encapsulation snare of  FIG. 8A  showing the surgical tool in an extended configuration; 
           [0035]      FIG. 9A  is an oblique view of the polyp encapsulation snare of  FIG. 8A  showing the surgical tool in a retracted configuration; 
           [0036]      FIG. 9B  is an oblique view of the polyp encapsulation snare of  FIG. 8A  showing the surgical tool in an extended configuration; and 
           [0037]      FIGS. 10A-I  illustrate a method of polyp encapsulation and resection in accordance with the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    Embodiments of the presently disclosed polyp encapsulation system and method are described herein in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As shown in the drawings and as described throughout the following description, and as is traditional when referring to relative positioning on an object, the term “proximal” refers to the end of the apparatus that is closer to the user and the term “distal” refers to the end of the apparatus that is further from the user. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. 
         [0039]    There is disclosed a polyp encapsulation device having a pouch that is shrinkable upon activation by a surgeon. Disposed circumferentially around the opening of the pouch is a wire loop snare for tightening the opening of the pouch around the polyp and for providing shrink activation energy, such as direct current electricity, alternating current electricity, or pulse-width modulated electrical current, to the pouch material. As illustrated in  FIGS. 1A ,  1 B, and  2 , an embodiment of a polyp encapsulation instrument  10  in accordance with the present disclosure includes a tubular housing  100 , a support member  105  that is slidably disposed within the tubular housing  100 , and a pouch assembly  115 . The polyp encapsulation instrument  10  has an undeployed configuration and a deployed configuration, as illustrated by  FIG. 1A  and  FIG. 1B , respectively. In the undeployed configuration, the sliding support member  105  is retracted within the tubular housing  100  forming a storage cavity  101  at the distal end thereof wherein the pouch assembly  115  may be stored in a generally folded, amorphous or irregularly-shaped configuration. The surgeon may introduce the instrument  10  to the surgical site in the undeployed configuration. Once positioned at the surgical site, the surgeon may actuate a deployment control, such as a hand lever (not shown), that causes support member  105  to slide distally which displaces the volume described by storage cavity  101 , thereby deploying pouch assembly  115 . 
         [0040]    Pouch assembly  115  includes an electrically conductive wire loop snare  125 ,  125 ′ having a proximal open end and a distal closed end, and a shrinkable pouch  140 . Wire loop snare  125 ,  125 ′ are joined at the distal closed end by insulating coupler  130 . When snare assembly  115  is in the deployed configuration, the distal portions of wire loop snare  125 ,  125 ′ assume a generally circular or semi-circular shape which describes the periphery of the opening of shrinkable pouch  140 . Wire loop snare  125 ,  125 ′ may be constructed of material having an elastic limit sufficient to enable stowage of the snare assembly  115  in storage cavity  101  as previously described herein, while remaining fully recoverable to the desired circular or semicircular share upon deployment. In an embodiment, wire loop snare  125 ,  125 ′ can be constructed of stainless steel or Nitinol, for example. The open ends of wire loop snare  125 ,  125 ′ communicate through at least one snare conduit  110 ,  110 ′, respectively, that may be formed within sliding support member  105 . Wire loop snare  125 ,  125 ′ is operably coupled at the proximal ends thereof to a source of activation energy, and to a tightening control, such as a second hand lever (not explicitly shown), that is operable by the surgeon for tightening the snare  125 ,  125 ′. After the pouch is positioned over the target polyp, the surgeon may actuate the tightening control and cause the open ends of wire loops snare  125 ,  125 ′ to be drawn in a proximal direction, thereby contracting the opening of the pouch around the base of the polyp. 
         [0041]    During actuation of the deployment control, wire loop snare  120 ,  125 ′ operates in a cooperative relationship with sliding member  105  for deployment such that wire loop snare  120 ,  125 ′ and slidable member  105  move as a single unit with respect to tubular housing  100 . Conversely, actuation of the tightening control causes wire loop snare  120 ,  125 ′ to move independently with respect to stationary sliding member  105  and tubular housing  100  for tightening the snare  125 ,  125 ′ around the polyp, as will be readily appreciated. 
         [0042]    Wire loop snare  125 ,  125 ′ are disposed circumferentially around the opening of shrinkable pouch  140  enclosed within a channel  142  described by a drawstring hem  120 . As best illustrated in  FIGS. 5A and 5B , drawstring hem  120  can be formed along the periphery of the opening of pouch  140  by rolled edge  145  of the pouch material. The resulting channel  142  is configured to allow movement of wire loop snare  125 ,  125 ′ within drawstring hem  120 , which thus facilitates tightening of the pouch assembly  115  around the targeted polyp. In an embodiment, channel  142  may be configured to provide frictional resistance to movement of wire loop snare  125 ,  125 ′ to maintain the position of wire loop snare  125 ,  125 ′ subsequent to tightening by the surgeon. Insulating coupler  130  is similarly disposed within channel  142 . Rolled edge  145  may be secured to the pouch material by any suitable manner of bonding, for example, by stitches  146 , by adhesive, and/or by heat welding. 
         [0043]    In one embodiment, pouch  140  includes at least one heating element  150  for delivering thermal energy to the pouch  140  for effectuating shrinkage thereof. The heating elements can form a heating array for delivering heat in an essentially uniform manner throughout the pouch  140  to cause the pouch  140  to shrink at a substantially uniform rate. It may also be desirable to cause the pouch  140  to shrink in a non-uniform manner. For example, it may be desirable to shrink the open region  140  of the pouch at faster rate than the closed region of the pouch  140  in order to facilitate encapsulation and to avoid squeezing the polyp from the pouch. In an alternate embodiment, the heating array may be configured to deliver heat in a non-uniform manner. It is also contemplated that the pouch walls may have varying thickness, to further tailor the rate and amount of shrinkage. In yet another embodiment, the pouch  140  includes a plurality of independent shrinking regions that may be activated individually or in combination by the surgeon in order to achieve a particular desired operative result. 
         [0044]    The heating elements  150  are electrically coupled to wire loop snare  125 ,  125 ′ to form a series circuit, parallel circuit, series-parallel circuit, or other suitable circuit topology. Heating elements  150  may be constructed of any conductive substance, and may be constructed from resistance wire such as Nichrome for efficiently converting electrical energy into the thermal energy required to effectuate pouch shrinkage. In an embodiment, a heating array that includes heating elements  150  are coupled in parallel to a common conductor  155 ,  155 ′, which, in turn, couple to wire loop snare  125 ,  125 ′ by lead wires  160 ,  160 ′, respectively, using any suitable type of connection, including crimping, soldering, and/or wire bonding. In an embodiment, common conductor  155 ,  155 ′ may also be a heating element. The heating elements  150  are incorporated into the pouch material by, for example, lamination, weaving, adhesive, bonding, or molding. Embodiments are contemplated wherein the heating element  150 , common conductor  155 ,  155 ′, and/or lead wire  160  are printed on the pouch. 
         [0045]    Pouch  140  may be constructed from any material having suitable heat-shrink properties, such as polyethylene or cross-linked polyolefin; mechanical properties, such as puncture resistance and tensile strength; and biocompatibility. The pouch may be constructed from material that is substantially opaque, or substantially translucent. Embodiments are also contemplated wherein the pouch is constructed of material that is substantially transparent, which may permit improved visualization of the operative site. 
         [0046]    Another embodiment envisioned within the scope of the present disclosure is illustrated in  FIGS. 3 ,  4 ,  6 A, and  6 B, wherein the wire loop snare is an electrosurgical electrode snare  220 . A shrinkable pouch  240  is slidably captured within a longitudinal slot  222  provided by electrosurgical electrode snare  220 . The slot  222  is configured to allow longitudinal movement of the pouch edge  241  with respect to the electrosurgical electrode snare  220 , while concurrently resisting “pullout” of the pouch material, i.e., undesired movement of the pouch material in a direction orthogonal to the longitudinal axis of the electrosurgical electrode snare  220 . By this arrangement, the electrosurgical electrode snare  220  may be tightened around the base of the polyp, causing the pouch material to slide within the groove, thereby effectuating ensnarement of the polyp within the pouch. The longitudinal slot  222  may include at least one internal longitudinal rib  221  configured to retain the pouch material and to resist pullout, while facilitating longitudinal movement of the electrosurgical electrode snare  220  with respect to the pouch  240 . In an embodiment, the longitudinal slot  222  may be dimensioned to frictionally resist loosening of the electrosurgical electrode snare  220 , or can be configured to minimize friction between the pouch edge  241  and slot  222 . First and second insulated wires  230  are provided on the outer surface of electrosurgical electrode snare  220 , preferably adjacent to and running substantially parallel to slot  222  for activating the pouch heating array as previously described herein. In an embodiment, the insulated wires  230  may have a substantially flat cross-section, as best illustrated in  FIGS. 7A and 7B . Insulated wires  230  may be affixed to electrosurgical electrode  220  in any suitable manner, for example, by adhesive or heat welding, or formed in place, for example, by injection molding. The insulated wires  230  are switchably coupled at the proximal end of the instrument to a source of activating energy, such as an electric current that is controlled by, for example, a handswitch or a footswitch. Insulated wires  230  are coupled to the pouch heating array  250 ,  255  by a lead  260  at a location substantially adjacent to the distal end of the electrosurgical electrode  220 , however, other coupling points are contemplated within the scope of the present disclosure. Electrosurgical electrode  220  may be configured as a monopolar or bipolar electrosurgical electrode. 
         [0047]    Yet another polyp encapsulation device having a shrinkable pouch according to the present disclosure is illustrated by  FIGS. 8A ,  8 B,  9 A and  9 B, wherein at least one surgical tool  370  having a retracted inactive position and an extended active position is included. The surgical tool  370  may be a scalpel that includes a cutting edge  371  for cutting biological material at the surgical site. In the retracted position, the surgical tool  370  is disposed within a channel  374  having an opening  375  at the distal end of a sliding member  305 , located in spaced relation to the at least one snare conduit  310 ,  310 ′. The proximal end of at least one surgical tool  370  is operably coupled to a corresponding surgical tool control, such as a handle or lever (not explicily shown), which may be actuated by the surgeon to cause the surgical tool  370  to move between the distal extended position, as best shown in  FIGS. 8B and 9B , and the retracted position as illustrated in  FIGS. 8A and 9A . 
         [0048]    Additionally or alternatively, the surgical tool  370  may be configured as an electrosurgical electrode for performing electrosurgical cutting, blending and/or coagulating at the operative site. In this configuration, the surgical tool  370  may be coupled to a source of electrosurgical energy such as, for example, an electrosurgical generator. The surgical tool  370  may be configured as a monopolar or bipolar electrosurgical electrode. As previously described above, the wire loop snare  320 ,  325 ′ and surgical tool  370  operate in a cooperative relationship with a sliding member  305  for deployment such that wire loop snare  320 ,  325 ′, surgical tool  370 , and sliding member  305  move as a single unit with respect to a tubular housing  300  by actuation of the deployment control (not shown). Conversely, wire loop snare  320 ,  325 ′ and surgical tool  370  may move independently from each other, and from sliding member  305  and tubular housing  300 , by actuation of a tightening control (not shown) and the corresponding surgical tool control (not shown), respectively, as will be readily understood by the skilled artisan. Other surgical tools and/or end effectors are contemplated within the scope of the present disclosure, such as, without limitation, graspers, sealers, clamps, irrigators, suction tubes, and video or fiber optic endoscopes. 
         [0049]    Turning now to  FIGS. 10A-10I  there is illustrated a method for encapsulating and resecting biologic tissue, such as a polyp P that is situated at a surgical site S within a lumen L, which may be an esophagus, colon, intestine, urethra, blood vessel, or other tubular anatomic structure. The disclosed method includes the steps of providing at the surgical site S an endoscopic instrument  400  having a polyp encapsulation snare  405  that includes a shrinkable pouch  415  in accordance with the present disclosure as illustrated in  FIG. 10A , deploying the polyp encapsulation snare  405  from a storage cavity  410  disposed within the instrument  400  as shown in  FIG. 10B , positioning the deployed polyp encapsulation snare  405  adjacent to the polyp P as illustrated in  FIG. 10C , positioning the polyp encapsulation snare  405  over the polyp P such that the pouch  415  envelops the polyp P as depicted in  FIG. 10D , tightening the snare  405  around the base B of polyp P as shown in  FIG. 10E , shrinking the pouch  415  to encapsulate and optionally or alternatively reduce the size of the polyp as shown in  FIG. 10F , providing an electrosurgical signal to the wire loop snare to sever the polyp P from the lumen L and/or from the polyp base B as shown in  FIG. 10G , and withdrawing the endoscopic instrument  400  including the snare  405  containing the resected polyp P′ from surgical site. 
         [0050]    The shrinking step of the disclosed method may additionally or alternatively include at least one of the steps of applying electrical energy to the pouch  415 , applying thermal energy to the pouch  415 , and/or applying a chemical to the pouch  415 . Additionally or alternatively, disclosed method includes the step of exposing the pouch  415  to body heat and/or bodily fluids to effectuate shrinkage of the pouch  415 . 
         [0051]    The provided method can additionally include coagulating or cauterizing the operative site substantially concurrently with, or subsequent to, the step of severing the polyp. Optionally or additionally, the method includes the step of extending from the endoscopic instrument  400  a surgical instrument  420  and performing at least one electrosurgical or non-electrosurgical procedure therewith at the operative site as depicted in  FIG. 10H . It is envisioned the steps of the above method may be performed in a different order than that described, and/or the operations performed within an individual step or steps may be desirably be combined into a single step without departing from the scope and spirit of the method disclosed herein. 
         [0052]    Further variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems, instruments and applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, which are also intended to be encompassed by the following claims.