US 5824082 Patch for endoscopic repair of hernias
ABSTRACT – A prosthesis for use in hernia repair surgery having a preformed prosthetic fabric supported along its periphery by shape memory alloy wire having a transformation temperature corresponding to normal body temperature allowing the prosthesis to be tightly rolled into a cylindrical configuration for delivery through a laparoscopic instrument and which deploys to a predetermined shape as it warms up to body temperature.
FIELD OF THE INVENTION
This invention relates to apparatus to be used in hernia repair surgery, and more particularly to a prosthetic hernia repair patch that can be rolled into a tube for laparoscopic delivery through a trocar and which deploys to a generally planar form when ejected from the trocar into the abdominal cavity.
BACKGROUND OF THE INVENTION
Since 1991, I have performed numerous laparoscopic hernia repair procedures on inguinal, ventral, incisional and umbilical hernias with a great deal of success in terms of patient satisfaction. When compared to open surgery, those having the laparoscopic procedure experience significantly less pain and more rapid return to normal activity.
In carrying out those procedures, I initially used a prosthetic patch made at the time of surgery from a sterile, woven, polypropylene mesh material that I folded in half to create a double layer and then cut to size, typically a 6 cm by 9 cm rectangle. Sutures were used to join the four corners of the rectangle and two additional sutures were positioned approximately midway along the unfolded edge. A slit was then created between these two additional sutures which was designed to accommodate the inferior epigastric vessels. Following dissection of the hernia sac away from the ipsilateral testicle and cord structures, the creation of a peritoneal incision and the subsequent dissection of the peritoneal flap and hernia sac away from the hernia defect and surrounding fascia and cord structures, the patch was rolled into a tube and inserted into a trocar sleeve that was then introduced through a larger diameter trocar, and delivered into the peritoneal cavity. A laparoscopic forceps was then used to unfurl the patch and place it anterior to the hernia defect and around the inferior epigastric vessels with the mesh covering both the direct and indirect hernia spaces. The mesh patch would then be held in place by stapling or suturing it to underlying fascia. Subsequently, the peritoneum was closed over the patch so that the entire piece of mesh was covered thereby.
While the above procedure proved quite successful in terms of outcomes, the need to fabricate the mesh patch at the time of surgery, the later difficulty in unrolling and positioning the mesh patch material relative to the direct and indirect hernia spaces and the need to then staple or suture the mesh patch in place necessarily adds significantly to the time and expense required for carrying out the procedure.
A need, therefore, exists for a hernia patch to be used in laparoscopic surgery that is prefabricated to conform to anatomical structures, that readily deploys when released from a tubular laparoscopic introducer and which will remain in place without a need for stapling or suturing to underlying facie. The present invention fulfills that need.
SUMMARY OF THE INVENTION
The hernia repair patch of the present invention comprises a wire frame that can be of various designs including, but not limited to, the form of a closed loop where the wire comprising the frame is a shape memory alloy. A synthetic prosthetic material, such as woven polypropylene or expanded PTFE (Gortex), is attached to and supported by the wire frame. The wire frame supporting the mesh material may be formed from NiTiNOL or other suitable shape memory alloy and can be attached to the prosthetic material so that it has an hour-glass shape when the alloy is in its austenite form and a rolled, cylindrical shape when in a martensite form. The atomic percent of nickel in the alloy is such that the alloy exhibits a transformation temperature at about 37° C. (body temperature). Thus, when the patch is cooled, it can be readily formed into a cylindrical configuration for placement in a delivery trocar. When ejected out of the trocar into the patient’s abdominal cavity, it warms to the point where the alloy is in its austenite form so that it springs into its functional, predetermined configuration. The narrowed central portion of an hour-glass shape patch accommodates the inferior epigastric vessels and cord structures while the opposed end lobes will cover the direct and indirect hernia space. Because the frame is integral to the patch, it does not migrate and, accordingly, need not be sutured or stapled in place. It remains anchored following its being covered by the peritoneum in a sandwich or laminated fashion.
The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawing.