Abstract:
A hernia prosthesis deployment device includes an elongated rod through which a drawstring extends forming a loop at the distal end. The size of the loop is controlled by pulling on an end of the drawstring extending from the proximal end of the rod. A plurality of independent segments are threaded onto the drawstring loop in bead-like fashion, such that when the loop is expanded, the loop with segments is flexible. When the loop is contracted, the segments force the loop into a planar configuration. A surgical patch is attached to the loop such that it can be folded and pushed into position in the body. Thereafter, the loop is contracted by pulling the drawstring forcing the loop and attached patch into a planar configuration to cover the defect to be repaired.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an apparatus for placing and deploying supple surgical materials such as surgical mesh within the body, and more particularly to a substantially planar surgical mesh prosthesis for bridging a hernia and an apparatus for placing and deploying the prosthesis. 
     BACKGROUND OF THE INVENTION 
     Modern surgical techniques are intended to be minimally invasive. Endoscopic surgery is a prime example of this minimally invasive approach and has led to the development of various instruments that may be inserted through a small incision to operate internally. In some circumstances, such as with specimen retrieval pouches or organ pouches and bags, the surgical instrument places, controls and/or deploys a supple material, e.g., a latex bag. The supple material may assume folded, expanded and contracted states, e.g., for inserting, opening and closing within the body. Accordingly, various apparatus have been devised to accomplish these transitions and functions relative to supple surgical materials like latex sheeting and textiles, but these apparatus are frequently complex, expensive and utilize exotic materials. 
     Minimally invasive procedures are also commonly employed in the treatment of hernias, e.g., in the placement of mesh surgical prostheses. Surgically implantable mesh patches for the repair of inguinal and other abdominal wall hernias are commonly used and provide tension-free repairs by bridging the hernia defect. Patches of this type constitute a structural support which decreases recurrence rates and because they do not require the displacement of tissues to cover the hernia, decrease postoperative discomfort. Frequently, prostheses of this type are sutured in place, i.e., proximate to the periphery of the patch. An alternative to suturing the prosthesis is to insert it into the properitoneal space. U.S. Pat. No. 5,916,225 to Kugel discloses a hernia prosthesis having a resilient ring made of synthetic material, such as nylon, polypropylene or polyester enclosed within a pocket formed by opposing planar segments of surgical mesh that are attached together to encapsulate the ring. A slit is provided in one of the planar segments to permit the surgeon to insert a finger therein in order to push the prosthesis through an incision in the abdominal wall into the properitoneal space and across the hernia. The resilient ring urges the pocket into a deployed planar configuration, i.e., to straighten the wrinkling and folding of the pocket that occurs in the course of its placement. The disadvantages associated with the device disclosed in U.S. Pat. No. 5,916,225 are that each layer of mesh is stiff and dense, such that the combination of two layers and the resilient ring constitutes a rigid, high mass prosthesis which tends to cause discomfort and resists conformance to the patient&#39;s anatomy. Further, the high mass prosthesis with resilient ring must be compressed into a stressed condition in order to be passed through the incision. Alternatively, the incision must be made large enough to pass the fully expanded prosthesis. 
     It is therefore an object of the present invention to provide a hernia repair prosthesis for use in a surgical hernia repair that has low mass, greater flexibility and that may be placed proximate to the site of the defect through a small incision in a stress free condition. More generally, it remains an objective to devise simple effective apparatus for positioning, deploying and controlling supple surgical material, such as a surgical mesh hernia prosthesis. 
     SUMMARY OF THE INVENTION 
     The problems and disadvantages associated with conventional supple surgical material deployment devices are overcome by the present invention which includes an elongated rod having a proximal end and a distal end. A drawstring with a first end and a second end runs along the length of the rod from the proximal end to the distal end and slidably passes through an opening at the distal end of the rod. The drawstring forms a loop at the distal end of the rod and the loop has a variable circumference varying between an expanded circumference and a reduced circumference, depending upon the position of said first end relative to said rod. A plurality of segments, each having a lumen therethrough, is threaded over the drawstring in the area of the loop. The segments bear against one another when the circumference of the loop is reduced and assume a relative alignment such that they are arranged to approximate a generally planar closed figure. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES 
     For a better understanding of the present invention, reference is made to the following detailed description of several exemplary embodiments considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a plan view of a surgical material deployment apparatus in accordance with an exemplary embodiment of the present invention; 
     FIG. 2 is a plan view of the deployment apparatus of FIG. 1 in a deployed state and conjoined to a hernia repair prosthesis; 
     FIG. 3 is a perspective view of the deployment apparatus and prosthesis of FIG. 2 in a folded, undeployed state; 
     FIG. 4 is a diagrammatic, perspective view of a releasable stitching arrangement that may be employed to releasably attach a hernia prosthesis to the deployment apparatus of the present invention; and 
     FIGS. 5 and 6 are diagrammatic views of second and third exemplary embodiments of the present invention, respectively. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a deployment apparatus  10  in accordance with the present invention having an elongated rod  12  with lumen  14  therein. The rod  12  may be grasped by the hand of a surgeon for positioning the deployment apparatus  10 . A drawstring  16  extends through the lumen  14  of the rod  12 , threads through a plurality of independent rigid, bead-like segments  18  then doubles back on itself to form a slipknot  20  to thereby define a loop  22  (combination of drawstring  16  and captured segments  18 ). The segments  18  are generally cylindrical as shown, but could be any other shape, such as, cubical or spherical, each having a lumen  24  therein through which the drawstring  16  may slidably pass. As a result, when the loop  22  has a greater length than the cumulative length of the segments placed end-to-end, the loop  22  is flexible. The slipknot  20  is preferably larger than the lumen  14 , such that when the drawstring  16  is pulled in a proximal direction, the slipknot  20  encounters the rod  12  and the loop  22  is reduced in circumference. Accordingly, rod  12  functions as a segment/knot pusher and also as a handle for the apparatus  10 . The loop  22  has a minimum circumference as determined by the cumulative length of the segments  18  as shown in FIG. 2, such that when the drawstring  16  is pulled taut, the segments  18  are inwardly radially compressed to configure the loop  22  into a rigid, composite, hoop-shaped structure. A limit knot  26  prevents the proximal end of the drawstring  16  from passing into the lumen  14  of the rod  12 . The deployment apparatus  10  can therefore assume a relaxed state (loop  22  flexible) and a deployed state (loop  22  rigid). This capacity can be utilized to control the state of supple surgical material that is attached to the loop  22 . For example, the loop  22  may be positioned about the neck of a specimen bag to allow it to be opened by causing the loop  22  to assume its rigid, hoop-shaped state. 
     FIG. 2 shows the deployment apparatus  10  of FIG. 1 after the drawstring  16  (see FIG. 1) has been pulled taut in a proximal direction. The segments  18  are pulled together as closely as possible, forcing the loop  22  with segments  18  into a generally circular configuration. A prosthesis (patch)  28  of surgical mesh material is attached to the loop  22  formed by the juxtaposed segments  18  and underlying drawstring  16 . The prosthesis  28  may be formed from any biologically compatible, flexible, porous medical textile, such as those commonly used for reinforcing and occluding tissue defects. Knitted polypropylene monofilament mesh fabrics such as those available from Ethicon, Inc. under the Prolene, Vicryl and Panacryl trademarks may be utilized to fabricate the prosthesis  28 . Other suitable mesh materials are available under the Marlex, Dacron, Teflon, Merselene and Polysorb (produced by United States Surgical Corporation) trademarks. Tissue regeneration may be induced through the use of absorbable materials in fabricating the prosthesis  28 . It is preferred that the mesh used to form the prosthesis  28  be simultaneously flexible and have a low mass with a high porosity/open area ratio. These objectives are met by a material described in a copending application entitled KNITTED SURGICAL MESH, application Ser. No. 09/723,854 filed Nov. 28, 2000 and owned by the assignee of the present application, such application being incorporated herein by reference. The foregoing material is commercially available from Ethicon, Inc. under the trademark PROLENE*SOFT. 
     The prosthesis  28  preferably has visible alternating stripes  30 ,  32  or other indicia to aid in identifying the orientation of the prosthesis  28  when it is being placed in the body of the patient. While a circular prosthesis  28  may be used in certain circumstances, an oblong or rectangular shape, having a greater extent in one dimension may also be utilized. Accordingly, the stripes  30 ,  32  may be used to orient an elongated prosthesis  28  at the surgical site, e.g., by presenting a readily appreciable indicia of orientation. The stripes  30 ,  32  may be provided by utilizing a pattern of different color fibers in the textile from which the prosthesis  28  is made. Alternatively, stripes or other indicia may be printed on or otherwise applied to the prosthesis  28 . 
     The prosthesis  28  may be attached to the loop  22  by stitching that interlocks to prevent the disassociation of the prosthesis  28  from the loop  22 . Another method for attachment is to weave the drawstring  16  through the prosthesis  28  at spaced points along the periphery of the loop  22  and intermediate selected segments  18 . Alternatively, the prosthesis  28  can be removably attached to the loop  22  by removable stitching, e.g., as shown below in FIG.  4 . Removable attachment permits the loop  22  to be removed after placement of the prosthesis  28  at the hernia repair site. In this manner, the thickness and rigidity of the prosthesis  28  can be reduced. Alternatively, the segments  18  and drawstring  16  may be made from materials that can be absorbed by the body, such that the entire loop  22  with attached prosthesis  28  can be left at the hernia repair site, e.g., by snipping the drawstring between the limit knot  26  and the rod  12  and withdrawing the rod  12 . 
     FIG. 3 shows the prosthesis  28  attached to the loop  22  prior to the tightening of the drawstring  16 . When the drawstring  16  is in the untightened state, the loop  22  is free to assume various shapes, permitting the folding of the attached prosthesis  28 . The prosthesis  28  can be folded prior to insertion into the surgical incision leading to the defect to be repaired, thereby reducing its size and permitting it to pass through a smaller incision. Once the prosthesis  28  is positioned proximate to the defect, the drawstring  16  can be pulled, forcing the segments  18  into the circular configuration shown in FIG.  2  and straightening the prosthesis  28  into a flattened configuration positioned across the defect. 
     FIG. 4 shows one exemplary method of implementing a removable stitching arrangement to releasably retain the prosthesis  28  (only a portion of which is shown to simplify the illustration) in association with the loop  22 . For simplicity of illustration, the loop  22  is shown as a solid elongated element rather than a composite of a plurality of segments  18  on a drawstring  16 . More particularly, thread  38  is tied at knot  40  to the loop  22 . The thread  38  passes under the loop  22  through a first hole H 1  in the prosthesis  28  to form a stitching loop S 1  back down through hole H 1 , under and around loop  22 , through hole H 2  to form stitching loop S 2 , back down through hole H 2 , and so forth to form stitching loop S 3 . The thread  34  is then formed into an elongated release loop  36  which is passed through the stitching loops S 1 , S 2 , S 3 , When the free end  38  of thread  34  is pulled, the release loop  36  is pulled through the stitching loops S 1 , S 2 , S 3 , allowing them to be withdrawn from holes H 1 , H 2 , H 3  and permitting the prosthesis  28  to be disassociated from the loop  22 . While only three releasable stitches, i.e., associated with S 1 , S 2 , and S 3  are shown, the same structures and principles of operation can be implemented around the entire periphery of the loop  22  to releasably secure the prosthesis  28  to the loop  22 . In this manner, the loop  22  can be removed from the surgical site after placement of the prosthesis  28 . The embodiment depicted in FIGS. 1-3 employs a slipknot  20  which can be either locking or non-locking, with the locking slipknot  20  being more appropriate for use in those instances when the loop  22  is left at the surgical site. Non-locking slipknots  20  facilitate removal of the loop  22 , as described further below. 
     The prosthesis  10  may be used in the surgical repair of a hernia in accordance with the procedure described in U.S. Pat. No. 5,916,225 to Kugel, such patent being incorporated herein for its teaching relative to this procedure, which is also known in the art. Briefly, the repair of an inguinal hernia is made in accordance with this known procedure utilizing the present invention by inserting the prosthesis  28  attached to a folded loop  22  through a relatively small, oblique incision, e.g., 2 to 3 centimeters in length, made in the patient&#39;s abdomen above the internal ring location of the inguinal hernia. To prepare for insertion of the prosthesis, the surgeon performs a dissection through the oblique incision deep into the patient&#39;s pro-peritoneal space, using the muscle splitting technique. This dissection process results in a pocket in the pro-peritoneal space that can receive the prosthesis  28 . The prosthesis  28  and loop  22  of the present invention can be then inserted into the cavity previously surgically formed in the pro-peritoneal space. After the prosthesis  28  and loop  22  are at the proper insertion depth, the drawstring  16  can be pulled taut to deploy the prosthesis  28  over the defect. After deployment, the drawstring  16  can be snipped to allow withdrawing the rod  12  and leaving the loop  22  and prosthesis  28  in place. Alternatively, the thread  34  attaching the prosthesis  28  to the loop  22  may be formed into releasable stitching, such that when a free end  38  of the thread  34  is pulled from a position outside the patient&#39;s body, the prosthesis  28  becomes disassociated from the loop  22 , allowing the loop  22  to be withdrawn from the surgical site but leaving the prosthesis  28  in place covering the defect. When the loop  22  is withdrawn following placement, it is preferred that the loop  22  be free to loosen when tension exerted on the drawstring  16  by the surgeon is released, i.e., it is preferred that the slipknot  20  be of the non-locking type or that a device  110 ,  210  as shown in FIGS. 5 and 6 be employed. In this manner, the loop  22  will become limp, allowing it to conform to the confines of the incision and to be removed without causing any unnecessary stress to the incision. 
     FIG. 5 shows a deployment apparatus  110  like that of FIG. 1 but having a pair of lumens  114   a  and  114   b . The elements of the embodiments shown in FIGS. 5 and 6 having similar form and function as those of the embodiment of FIGS. 1-3 have been designated by corresponding reference numerals increased by one hundred and two hundred, respectively. Instead of utilizing a slipknot for forming the loop  122 , the loop  122  is formed by the passage of the drawstring  116  into two separate lumens  114   a ,  114   b . A pair of limit knots  126   a ,  126   b  prevent the drawstring  116  from inadvertently slipping through the rod  112  and releasing the segments  118 . The limit knots  126   a ,  126   b  also limit the expanded size of the loop  122 . 
     FIG. 6 depicts yet another deployment apparatus  210  wherein both ends of the drawstring  216  pass through the lumen  214  to form the loop  222  and two limit knots  226   a ,  226   b  limit the expansion of the loop  222 . It should be appreciated that the ends of the drawstring  116 ,  216  protruding from the proximal end of the rod  112 ,  212  in FIGS. 5 and 6 respectively, could be tied together to unify them and provide a common limit knot, or could both be tied to a single common drawstring. 
     It should be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the invention as defined in the appended claims. For example, the shape of the segments  18  may be varied such that they interact in a specific way to give the resultant loop  22  a specific shape, e.g., in the manner of a ball and socket or abutting angled facets. While the present invention has been explained in terms of its use in hernia repair, there are other applications for introducing and deploying a supple surgical material into the body, such as in using specimen retrieval bags. Accordingly, all such variations and modifications in form or use are intended to be included within the scope of the invention as defined in the appended claims.