Abstract:
A surgical instrument for retrieving tissue from a patient. The instrument includes an elongated support tube having a proximal end and a distal end, and an elongated inner rod slidably and coaxially disposed within the support tube. The rod has a removable pouch attached thereto, wherein the pouch is initially disposed within the support tube, and wherein distal movement of the rod ejects the pouch from the tube. The instrument further includes a mechanism engaging the rod such that after the rod has initially been moved distally, the mechanism prevents proximal motion of the rod. The mechanism disengaging upon total ejection of the bag from the tube, and thereafter allows proximal and distal movement of the rod.

Description:
FIELD OF THE INVENTION 
     The present invention relates, in general, to surgical instruments for retrieving tissue and, more particularly, to endoscopic surgical instruments such as pouches or specimen retrieval bags for the removal of tissue through a small incision. 
     BACKGROUND OF THE INVENTION 
     Endoscopic surgery is a procedure wherein surgery is performed through a series of small openings or incisions in a patient. This type of surgery reduces or eliminates the need for large incisions and has changed some of the major open surgical procedures such as gall bladder removal to simple outpatient surgery. Consequently, the patient&#39;s recovery time has changed from weeks to days. These types of surgeries can be used for repairing defects or for the removal of diseased tissue or organs from areas of the body such as the abdominal cavity. 
     Of interest is the removal or excision of biological material or tissue from the body through a small opening such as an incision, a small natural orifice, or through a small diameter Laparoscopic access port such as a trocar. Tissue can have many types or forms but fall into three general categories: firm tissue such as muscle and solid tumors, soft tissues such as liver, and fluid filled tissues such as a cyst, a gall bladder, a spleen, or an inflamed appendix. Some tissue can be a mix of multiple categories. For example, an inflamed gall bladder can be a mix of hardened gallstones, fluids such as bile and pus, and an outer covering of firm tissue. 
     One challenge that exists with minimally invasive surgery is the removal of the excised tissue through the small opening. A time-honored solution is the manual cutting of the large tissue mass into small pieces that can fit through the opening. However, with this process fragments of tissue can be dropped and fluids can be spilled into the body cavity. This can cause complications if the excised tissue is cancerous or infected such as the seeding and re-spreading of cancer, or the spreading of an inflammation to healthy tissue. 
     In answer to the above challenges, surgical pouches or specimen retrieval bags were developed. The specimen retrieval bags are placed into an inner cavity of the body, the bags are opened, and the diseased tissue is placed within. The specimen retrieval bags are then closed to prevent the migration of tissue and fluids from the bag into the inner cavity of the body. After placing diseased tissue into the open specimen retrieval bag, the bag is closed and pulled from the opening in the patient. Drawstrings are typically used to close the specimen retrieval bag in the body and to draw the bag out of the opening in the body. 
     The small opening has forced several interesting design challenges to the makers of the specimen retrieval pouches. That is, the specimen retrieval pouches must be tightly rolled up or constrained to fit into the small opening within the patient, and fully opened or unfurled when deployed within the patient. To accomplish the above goals, a surgical deployment instrument was created. The surgical deployment instrument contains a tightly rolled or constrained specimen retrieval bag and a deployment mechanism that ejects and opens the bag from the distal end of the instrument. The surgeon activates the deployment mechanism by pushing on a deployment lever once the specimen retrieval bag is within the patient. Metallic spring arms are generally used to push the tightly rolled bag from the surgical deployment instrument and to spread open the opening of the bag. The excised tissue is placed into the open specimen retrieval bag, and the bag is closed by simultaneously detaching the bag from the spring arms and closing the opening of the bag with a drawstring. The spring arms are withdrawn back into the surgical deployment device by pulling the deployment lever back out of the surgical deployment instrument. The captured tissue is removed from the opening within the patient by pulling on the drawstrings to withdraw the specimen retrieval bag from the patient. Surgical instruments of this type are well known in the art and are described in U.S. Pat. No. 5,465,731 by Bell et al. , in U.S. Pat. No. 5,480,404 by Kammerer et al. , and in U.S. Pat. No. 5,647,372 by Tovey et al. which are incorporated herein by reference. 
     Specimen retrieval instruments have a specimen retrieval bag that is used to hold excised tissue. The specimen retrieval bags are generally held in an elongated support tube in a constrained condition. The specimen retrieval bag is inserted into the patient in the constrained state and the surgical retrieval instrument is fired to eject the bag from the elongated support tube and deploy it in an open state. Excised tissue is inserted into the open specimen retrieval bag and the bag is closed and detached from the specimen retrieval instrument. The fired specimen retrieval instrument and filled specimen retrieval bags are removed from the patient separately. Specimen retrieval instruments are well known in the art such as those described by Kammerer et al. in U.S. Pat. No. 5,480,404 and by Rousseau in U.S. Pat. No. 5,971,995, both of which are hereby incorporated by reference. 
     Whereas the above specimen retrieval bags and surgical deployment mechanisms worked well, in some cases, a surgeon could inadvertently partially activate the bag deployment mechanism and partially deploy the bag from the instrument. When the surgeon attempted to correct the mistake by de-activating the deployment mechanism, the bag could be partially detached from the metallic arms and fail to open properly. The partially opened bag, in some cases, was unusable and could require a replacement surgical instrument. To address this issue, motion control mechanisms or one way ratchet mechanisms can be incorporated with the surgical deployment instrument. Dual one way ratchet mechanisms are taught in U.S. Pat. No. 5,971,995 by Rousseau, each ratchet mechanism being fully engaged at all times. One ratchet mechanism limits proximal motion and one ratchet mechanism limits distal motion. Three nested and telescoping elements are provided, with two elements, one of which is the deployment lever, moving into the instrument to deploy the bag and one element, the deployment lever, moving out of the instrument to close and release the specimen retrieval bag. One ratchet mechanism limits travel of one of the two elements moving into the instrument and the second ratchet mechanism limits movement of the deployment lever moving out of the instrument. However, the dual ratchet mechanisms of the Rousseau device cannot prevent the surgeon from partially inserting the deployment lever and partially withdrawing the deployment lever. These actions can partially deploy the specimen retrieval bag from the surgical instrument. 
     What is needed is a simple low cost surgical deployment instrument that offers all of the advantages listed above and overcomes the needs described above. Thus, it would be advantageous to provide an improved simple motion control mechanism or ratchet mechanism that prevents the partial deployment of the specimen retrieval bag. . Presently, there are no known surgical deployment instruments that can provide the surgeon with the improvements and benefits described above. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided a surgical instrument for retrieving tissue from a patient. The instrument includes an elongated support tube having a proximal end and a distal end, and an elongated inner rod slidably and coaxially disposed within the support tube. The rod has a removable pouch attached thereto, wherein the pouch is initially disposed within the support tube, and wherein distal movement of the rod ejects the pouch from the tube. The instrument further includes a mechanism engaging the rod such that after the rod has initially been moved distally, the mechanism prevents proximal motion of the rod. The mechanism disengaging upon total ejection of the bag from the tube, and thereafter allows proximal and distal movement of the rod. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
     FIG. 1 illustrates an isometric view of an un-actuated specimen retrieval instrument with a push-pull rod extending proximally from a handle, the handle is located at a proximal end of a support tube and an improved specimen retrieval bag is constrained within a distal end of the support tube, 
     FIG. 2 illustrates an isometric view of an actuated specimen retrieval instrument of FIG. 1, the push/pull rod is shown fully inserted into the handle and support tube to deploy the improved specimen retrieval bag from the support tube; 
     FIG. 3 illustrates an exploded isometric view of the active elements of the improved ratchet mechanism of the present invention; 
     FIG. 4 illustrates a cross-sectional view of the improved one way ratchet mechanism of the present invention when the push pull rod is in the un-actuated position of FIG. 1 and a one way ratchet on the push/pull rod is actively engaged with a spring-loaded bullet to limit the direction of motion of the push pull rod to that shown by the arrow; 
     FIG. 5 illustrates a cross-sectional view of the improved one way ratchet mechanism of the present invention when the push/pull rod is fully inserted into the support tube as shown in FIG.  2 . to permanently disengage the one way ratchet mechanism by pushing the spring loaded bullet downwardly to lockingly engage with the handle; 
     FIG. 6 illustrates a cross-sectional view of the improved one way ratchet mechanism of the present invention after the push pull rod has been pulled out of the support tube to release and close the specimen retrieval bag showing the spring loaded bullet remaining locked in the downward position and the one way ratchet mechanism permanently disengaged. 
     FIG. 7 illustrates a side view of a prior art specimen retrieval bag illustrating the two continuous lines of heat staking located under a closure noose; 
     FIG. 8 illustrates a side view of the improved specimen retrieval bag of FIG. 2 having an open end and a closed end and a closure noose, the improved specimen bag having two intermittent weld lines at the open end to enhance the closure of the specimen retrieval bag; 
     FIG. 9 illustrates a second side view of the specimen retrieval bag of FIG. 2 including diagonal lines between the two intermittent weld lines, the diagonal lines representing the pleat fold lines between the pleat introducers; 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the Figures wherein like numerals indicate the same element throughout the views, there is shown in FIG. 1 an isometric view of an un-actuated specimen retrieval instrument  20  ready for insertion into a patient. The specimen retrieval instrument  20  has an elongated support tube  25  with a handle  30  at a proximal end. Handle  30  has an upper half  32  and a lower half  33  fixedly attached to the elongated support tube  25 . A pair of opposed finger loops  31  extend from the handle  30 , and an unobstructed passageway  26  extends through the support tube  25  and handle  30 . A push/pull rod  45  is slidingly located within the passageway  26  and has a thumb ring  46  at a proximal end and a pair of spring arms at a distal end. An improved specimen retrieval bag  75  is attached to a distal end of the push/pull rod  45  and is shown constrained within the passageway  26  at the distal end of the support tube  25 . 
     FIG. 2 is an isometric view of the improved specimen retrieval instrument  20  after the instrument has been actuated to deploy the improved specimen retrieval bag  75  from the distal end of the support tube  25 . The push/pull rod  45  has been fully inserted into the specimen retrieval instrument  20  and has pushed the improved specimen retrieval bag  75  from the distal end of the support tube  25  and locked a cinching plug  27  into a notch  28  in the support tube  25 . A pair of opposed spring arms  47  releasably attaches improved specimen retrieval bag  75  to the push/pull rod  45 . A closure string  95  is removably attached to the median of push/pull rod  45  and extends distally from an opening (not shown) within the cinching plug  27 . Closure string  95  terminates in a captivated closeable noose  96  extending around the periphery of the open end  76  of the improved specimen retrieval bag  75 . A slipknot  97  is used on the noose  96  so it can be closed as the push/pull rod  45  is pulled distally. Slipknot  97  resides in contact (not shown) with the cinching plug  27  just below the spring arms  47 . Spring arms  47  spread open as they are released from the support tube  25  into a “Y” shape to open an open end  76  of the improved specimen retrieval bag  75 . Spring arms are retained within channels  78  that are formed within each side of the improved specimen retrieval bag  75 . Once the specimen retrieval bag is fully deployed, the one way ratchet mechanism  55  is permanently disengaged. Withdrawal of the unlocked push/pull rod  45  into the support tube  25  simultaneously withdraws the spring arms  47  from the channels  78  and closes the noose  96  to both disengage the improved specimen retrieval bag  75  from the end of the specimen retrieval instrument  20  and to close it. Spring arms  47  can be formed from a spring material such as stainless steel, nitinol, steel spring alloys, copper spring alloys, or any other material that can be stored in a deformed shape and return to an initial or near initial shape when released 
     An improved motion limiting mechanism or one way ratchet mechanism  55  of the present invention (FIG. 6) is located within the handle  30  and operably engages with the push/pull rod  45 . One way ratchet mechanism  55  operates only during the deployment of the improved specimen retrieval bag  75  from the elongated support tube  25 . One way ratchet mechanism  55  slips during initial insertion of the push/pull rod  45  (to deploy the improved specimen retrieval bag  75 ) and locks if the attempt is made to withdraw the push/pull rod  45  during the initial deployment stroke. Once the improved specimen retrieval bag  75  is fully deployed from the end of the support tube  25 , the one way ratchet mechanism  55  of the present invention permanently disengages and provides unrestricted proximal and distal movement of the push/pull rod  45 . 
     The one way ratchet mechanism  55  described above is only active during the push stroke (to deploy the improved specimen retrieval bag  75 ) to prevent a surgeon from partially deploying the improved specimen retrieval bag  75  and then partially withdrawing the spring arms  47  from the improved specimen retrieval bag  75 . The one way ratchet mechanism  55  is primarily located within the lower half  33  of the handle  30  (FIG. 2) and is shown in FIGS. 4-6. 
     FIG. 3 shows an exploded view of the active elements that make up the one way ratchet mechanism  55 . One way ratchet mechanism  55  consists of a spring  60 , a male feature or bullet  56  and the push/pull rod  45 . Spring  60  normally pushes bullet  56  upwardly into operative engagement with a series of female features or pockets  48  equally spaced longitudinally along the bottom (as shown in FIGS. 1 and 2) of the push/pull rod  45 . Pockets  48  interact with the bullet  56  to produce the desired one way ratchet action. Pockets  48  have an angled pocket ramp  49  on the proximal side, a vertical pocket flat  50  on the distal side, and a pocket floor  51 . A locking blade  52  is located next to the thumb ring  46  at the distal end of the push/pull rod  45  and has a locking ramp  53  and a locking flat  54 . In FIG. 3, the proximal end of push/pull rod  45  is shown and thumb ring  46  is sectioned. 
     FIG. 4 is a cross-section of the assembled one way ratchet mechanism  55  within handle  30  when the push/pull rod  45  is fully extending from the handle  30  and ready to deploy the constrained improved specimen retrieval bag  75  from the distal end of the support tube  25  (FIG.  1 ). The engagement end  57  of the bullet  56  is being pressed against the pocket floor  51  by spring  60 . The push/pull rod  45  is prevented from being pulled out (to the right in FIGS. 4-6) by the contact of the pocket flat  50  with the bullet  56 . 
     Push/pull rod  45  is free to move distally (arrow direction) to deploy the improved specimen retrieval bag  75 . Distal movement of the push/pull rod  45  brings the bullet  56  into contact with the pocket ramp  49  and bullet  56  moves downwardly as the ramp moves distally. As distal movement of push/pull rod  45  continues bullet  56  pops into the adjacent pocket  48 . Any attempt to move the push/pull rod  45  proximally results in the bullet  56  contacting the locking ledge  34  of the pocket  48  (in which the bullet  56  resides) and prevents the proximal motion. Distal motion of push/pull rod  45  is not restricted. 
     FIG. 5 shows a cross-section of the assembled one way ratchet mechanism  55  when the push/pull rod  45  is fully inserted (see arrow) into specimen retrieval instrument  20 . Improved specimen retrieval bag  75  is fully deployed from the distal end of the support tube  25  (FIG. 2) by this action. As shown, the bullet  56  has traversed all of the pockets  48  within the push pull rod  45  and has been pushed downwardly to the lowest position by the locking ramp  53  with the engagement end  57  of the bullet  56  resting on the locking flat  54 . In this locked position, the hook  59  on deflectable locking arm  58  is retained or locked onto the locking ledge  34  of the lower half  33  of handle  30 . When push/pull rod  45  is moved proximally (arrow direction), the locking blade  52  moves away from the bullet  56  and the locking engagement between hook  59  and locking ledge  34  holds the bullet  56  at the locked position. With the bullet  56  in the locked position, the bullet  56  can no longer interface with the pockets  48  and the one way ratchet mechanism  55  is permanently disengaged. With the bullet  56  in the locked position, the push/pull rod  45  is free to move in either direction. 
     FIG. 6 illustrates a cross-sectional view of the improved one way ratchet mechanism  55  of the present invention after the push pull rod  45  has been pulled out of the support tube  25  (see arrow) to release and close the improved specimen retrieval bag  75 . The push/pull rod is in the same position as shown in FIG. 4, but bullet  56  is in the locked position, and the one way ratchet mechanism is permanently disengaged. 
     Specimen retrieval bags are well known in the art for the reception and removal of tissue from the body. A prior art retrieval bag  175  is shown in FIG.  7  and has an open end  176 , a closed end  177  and a closure mechanism such as closure string  195  captured around the open end  176 . Closure string  195  is formed into a noose  196  by a slipknot  197 . The prior art retrieval bag  175  is generally formed from a pair of opposed walls  179 , each of which are cut from at least one layer of elastomeric or polymeric material. Walls  179  are constructed from at least one layer of an elastomeric or polymeric material such as but not limited to Polyurethane, Polyethylene, Polypropelene, Silicone, Vinyl, or Teflon. The walls  179  can be cut at an angle to produce a tapered retrieval bag that. 
     Multiple layer construction of the walls  179  are common and can incorporate flexible metal meshes, thermoformed plastic meshes, fabrics, or Kevlar for reinforcement. As shown, a pair of identical walls  179  are cut from flat sheets of Polyurethane into a desired shape with sides  180  tapered as shown to facilitate removal from the patient. The opposed pair of walls  179  are aligned together and attached together along the sides  180  and closed end  177  by gluing, heat welding, or ultrasonically welding to form a bag. 
     The closure string  195  is captured at the open end  176  of the prior art retrieval bag  175  by first folding over a portion of the open end of wall  179  to create a fold wall  181  in contact with the exterior of the wall  179  of the bag. Circular closure noose  196  of the closure string  195  is then placed around the prior art retrieval bag  175  and slid up into a crotch  182  of the fold between the interior surface of the fold wall  181  and the exterior surface of the bag wall  179 . Alternately, a number of other closure mechanisms can be used such as a belt or a cable tie. The interior surface of the fold wall  181  is then attached to the exterior surface of the bag wall  179  in a continuous line, henceforth referred to as first continuous weld  185 , located just below the closure noose  196  to capture the closure noose  196 . Any one of the attachment methods listed above can form the continuous weld but generally heat staking is used. Heat staking uses a combination of heat and pressure to weld two layers of wall  179  together. This process can emboss or raise a rib of material from the surface of the wall  179 . Care must be taken to ensure that the as first continuous weld  185  is present on each side of the prior art retrieval bag  175 , that the process does not weld the bag closed, and that the noose  196  slides freely within. The first continuous weld  185  slidingly captures the closure noose  196  within the crotch of prior art retrieval bag  175  and enables the closure string  195  to move as closure noose  196  constricts. A second continuous weld line  190  is placed below the first continuous weld line  185  on both sides of the bag to create channels  178  therebetween for the reception of the spring arms  47  (shown as dashed lines). 
     FIGS. 8 and 9 illustrate side views of the improved specimen retrieval bag  75 , initially shown in FIG. 2 as deployed from the specimen retrieval instrument  20 . Improved specimen retrieval bag  75  is generally similar in design and function to the prior art specimen retrieval bag  175 , but offers some significant improvements over the prior art bag. Many of the features of the improved specimen retrieval bag  75  are identical to those of the prior art bag  175 , but will be given different element numbers for clarity. Improved specimen retrieval bag  75  differs from the prior art in the area around the open end  76  and in the way that the bag closes. 
     As shown, the improved specimen retrieval bag  75  also has an open end  76 , a closed end  77  and a closure mechanism such as closure string  95 . Like the prior art retrieval bag  175 , the improved specimen retrieval bag  75  can be initially constructed from the same materials and processes described above. That is, the joining of two flat sheets with glue, heat welding, or ultrasonically welding along the sides  80  and closed end  77  to make a bag. 
     Closure string  95  can be identical to that used by the prior art retrieval bag  175  and is captured at the open end  76  of the improved retrieval bag  75  by folding over a portion of the open end of wall  79  to create a fold wall  81 . Circular closure noose  96  is then placed around the improved retrieval bag  75  and slid up into a crotch  82  of the fold between the interior surface of the fold wall  81  and the exterior surface of the bag wall  79 . Unlike the prior art retrieval bag  175 , the fold wall  81  is attached to exterior wall  79  of the bag in a different manner to provide improved benefits to the user. Carefully staggered intermittent attachment points or first intermittent welds  86  on the improved retrieval bag  75  replace the continuous welds used by prior art retrieval bag  175 . Thus, in FIG. 8, the noose  96  is secured around the open end  76  by a first intermittent weld line  85 . A second intermittent weld line  90  is formed from spaced apart second intermittent weld areas  92  and form channels  78  on both sides of the bag between the first and second intermittent weld lines  85 ,  90 . The welded areas of the first and second intermittent weld lines  85 ,  90  are stiffer than the surrounding wall  79  as they are composed of two layers of wall  79  that are bonded together. Additionally, the welded areas and can be embossed or raised outwardly from the surface of the bag from the heat staking or welding process. The channels  78  are provided to receive spring arms  47  and to removable hold the improved specimen retrieval bag  75  on the push/pull rod  45 . 
     The intermittent welds on the first and second intermittent weld lines  85  and  90  are spaced apart by sections of unattached material. The spacing between the first intermittent weld areas  86  is defined by a length “A”, and the spacing between the second intermittent welds is defined by a length “B”. The “A” spacing is preferably larger than the “B” spacing. The first intermittent weld areas  86  are staggered horizontally relative to the second intermittent weld areas  92  (FIG.  8  and  9 ). 
     Intermittent weld lines  85 ,  90  offer enhanced closure of the improved retrieval bag  75  because they offer alternating areas of stiff (welded) and less stiff (unwelded) wall  79 . It is well known phenomenon that when loaded, a less stiff area will buckle or deform before a stiffer area. With proper design, this tendency can be used to enhance the closure of the improved specimen retrieval bag  75  by forcing the bag to buckle or fold in a desired manner as it closes. 
     Looking at the first intermittent weld line  85 , intermittent weld line  85  is composed of alternating first intermittent weld areas  86  and unattached areas or lengths “A”. As noose  96  closes, the unattached lengths “A” will buckle or bunch before the intermittent weld areas  86 . The spacing of length “A” is maximized between the first intermittent weld areas  86  in the first intermittent weld line  85  to allow the maximum amount of unattached material to easily buckle or bunch between the welds as the noose  96  is tightened. This reduces the force to close, and minimize the size of the closed open end  76 . The unattached material “A” between the first intermittent weld areas  86  buckle first, and the stiffer first intermittent welded areas  86  buckle second. Thus, the alternating areas of intermittent weld areas  86  and unattached areas or lengths “A” within the first intermittent weld lines offer alternating zones of controlled buckling during closure. The alternating zones of controlled buckling provide uniformity during the closure process and reduce uneven closure caused by localized bunching. The above reasons enable the first intermittent weld line  85  to be closed tighter than the second intermittent weld line  90  and enhances the closure of the bag. 
     The second intermittent weld line  90  is also composed of alternating areas of weld defined by second intermittent weld areas  92 , and unattached areas defined by the unattached lengths “B”. The lengths “B” of unattached wall material are minimized in the second intermittent weld line  90  and are staggered to reside directly below the first weld areas. This is done to produce controlled buckling and folding within the improved specimen retrieval bag  75  as it closes. As shown in FIG. 9, this effect can be used to produce fold lines such as diagonal fold lines  83  that induce pleats (along the diagonal fold lines  83 ) in the wall  79  of the improved specimen retrieval bag  75  as it is drawn closed. The induced pleats provide uniformity of closure, reduce the size of the closed open end  76  and make it easier to remove the filled improved specimen retrieval bag  75  from the patient. A fold angle θ between the diagonal fold lines  83  and the open end  76  could be between about 1 degree and between about 90 degrees. 
     Whereas intermittent welds are used in the present invention to induce controlled buckling and folding, other mechanisms can be employed. That is, alternating areas of increased and lessened stiffness are used to force the improved specimen retrieval bag  75  to fold as it closes. Whereas welds and raised sections are used to increase stiffness in localized areas, many alternate embodiments are available. For example, alternating areas of increasing thickness and reduced thickness can produce the same effect. Examples of other embodiments or combinations of embodiments that can accomplish this desired effect are: attachment of rigid or semi-rigid sections of materials such as plastic features onto the improved specimen retrieval bag  75 , the use of stiff glues to attach the fold wall  81  onto the pouch, the embossment of stiffening features onto the improved specimen retrieval bag  75 , wall sections of different durometer, or the pre-placement of folds in the specimen retrieval bag with heat and pressure (similar to ironing pleats into a women&#39;s skirts). Several alternate embodiments are listed, but here are many more embodiments that can accomplish the same goals. 
     Surgical Procedure Using a Specimen Retrieval Instrument (Not Shown) 
     Specimen retrieval instruments  20  are frequently used during a cholecystectomy or gall bladder removal. During this endoscopic surgical procedure, the surgeon sedates the patient and insufflates the patient&#39;s abdomen with carbon dioxide gas. Next, a series of endoscopic access ports or trocars are placed into the patient&#39;s inflated abdomen for the passage of endoscopic instruments therein. The surgeon places a viewing device or endoscope into the patient to visualize the gall bladder and surgical site on a monitor. By viewing the monitor, the surgeon is able to identify, clip, and cut the cystic duct and cystic artery. Next, the gall bladder is carefully removed from the bed of the liver and held in a surgical grasping instrument. An un-actuated specimen retrieval instrument  20  (FIG. 1) is inserted into one of the trocar access ports to retrieve the excised tissue. 
     Placing his thumb into the thumb ring  46  and index and second fingers into the finger loops  31 , the surgeon begins to eject the improved specimen retrieval bag from the specimen retrieval instrument by pushing the thumb ring into the specimen retrieval instrument  20 . As the improved specimen retrieval bag  75  is ejected from the support tube, the spring arms  47  began to spread and to open the open end  76  of the bag. During the ejection process, the surgeon inadvertently attempts to pull the thumb ring  46  and push/pull rod  45  from the instrument, but is prevented by the one way ratchet mechanism  55 . Once the improved specimen retrieval bag  75  is fully ejected from the support tube  25  (FIG.  2 ), the one way ratchet mechanism  55  is permanently disabled and proximal and distal movement of the push/pull rod  45  is possible. 
     The surgeon then places the excised gall bladder into the open end  76  of the improved specimen retrieval bag with a grasping instrument and releases it. Next, the surgeon simultaneously closes the improved specimen retrieval bag  75  around the excised gall bladder and releases it from the spring arms  47  by pulling the thumb ring  46  and push pull rod  45  proximally out of the support tube  25  and handle  30 . As the push/pull rod  45  is pulled, the spring arms are pulled proximally from the channels  78  within the improved specimen retrieval bag  75 , the closure string  95  is pulled through the slipknot  97  to close the noose  96 , and a free end of the closure string  95  is exposed. Slipknot  97  is prevented from moving proximally by the cinching plug  27 . As the improved specimen retrieval bag  75  is closed, the intermittent welding on the first and second intermittent weld lines  85 ,  90  ensures uniform closure of the bag. Angular fold lines  83  form in the less rigid portions of the wall  79  and induce pleats into the bag as it closes and provide improved, consistent bag closure. Once the improved specimen retrieval bag  75  is detached from the spring arms  47 , the improved specimen retrieval bag remains attached to the specimen retrieval instrument  20  by closure string  95 . The free end of the closure string  95  is easily detached from the push/pull rod outside of the patient. As the specimen retrieval instrument  20  is withdrawn from the patient from the trocar, the closure string  95  is pulled out of the support tube  25 . 
     To remove the filled improved specimen retrieval bag  75  from the patient, the surgeon pulls on the closure string  95  to draw the pleated and closed open end  76  of the filled improved specimen retrieval bag  75  into the cannula of the trocar. While maintaining tension on the closure string  95 , the trocar and attached filled improved specimen retrieval bag  75  are pulled from the patient through the trocar incision. 
     It will be recognized that equivalent structures may be substituted for the structures illustrated and described herein and that the described embodiment of the invention is not the only structure which may be employed to implement the claimed invention. As one example of an equivalent structure which may be used to implement the present invention, such as the attachment of rigid or semi-rigid materials to the wall of the surgical retrieval pouch to produce alternating areas of stiffness and less-stiffness. As a further example of an equivalent structure which may be used to implement the present invention, alternating areas of different durometers may be used. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function. 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.