Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Tissue
Reexamination Certificate
1998-01-09
2003-11-25
Prebilic, Paul B. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Tissue
C623S023720, C600S036000, C606S051000
Reexamination Certificate
active
06652595
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mesh prosthesis. In particular, the present invention relates to a universal, surgical mesh prosthesis for hernia repair.
2. Description of the Prior Art
Surgical mesh prostheses of various different types have long been known and have long been used for hernia repair. The general surgical technique for hernia repair is to utilize a surgical mesh prosthesis, also called a hernia patch, over the hernia defect. The hernia patch has sufficient strength to resist the tendency of the hernia sack to protrude. The hernia patch is placed over the hernia defect and sutured to the surrounding tissue. This technique avoids undesirable, additional tension on the musculofascial tissue and minimizes the reoccurrence of a hernia.
Examples of hernia patches for hernia repairs can be found in U.S. Pat. Nos. 5,368,602; 5,356,432; 5,326,355; 5,292,328; 5,290,217; 5,254,133; and 5,147,374. Endoscopic and laparoscopic surgical techniques have been developed for repairing hernias with a hernia patch. Examples of these techniques can be found in U.S. Pat. Nos. 4,769,038; 5,379,754; and 5,370,650.
The hernia patches described in the prior art generally fall in two classes. The first class of hernia patch is formed of polypropylene material such as marketed by C. R. Bard, Inc. under the trademark MARLEX® or by United States Surgical Corporation under the trademark SURGIPRO®. A second class of hernia patch is mesh material formed of polytetrafluoroethylene (PTFE) such as marketed by W. L. Gore & Associates, Inc., under the trademark GORETEX®.
The two above-identified classes of hernia repair patches of the prior art each provide distinct advantages and disadvantages. The patches formed of polypropylene provide an excellent degree of tissue ingrowth for muscles and provide a sufficiently strong patch. However, the polypropylene hernia repair patches can result in unwanted adhesion of the abdominal viscera. When such adhesions occur, a “reopening” of the patient becomes increasingly difficult. The reopening of a patient in which unwanted adhesion occurred requires painstaking removal and separation of the abdominal viscera from the prosthetic material. Such a situation increases the danger of injury to the abdominal viscera as well as significantly increasing the length of the operation. As described in the above-noted patents, such reopenings are not uncommon in hernia operations.
The polytetrafluoroethylene (PTFE) hernia patches provide the advantage of minimizing or eliminating the adherence of the abdominal viscera to the hernia patch. The polytetrafluoroethylene hernia patches can easily be cut through without complications in a reopening procedure. However, the PTFE hernia patches are not as readily attachable to the muscle wall as the polypropylene meshes of the hernia patches described above. In view of the above discussion, it is clear that, in certain situations, the polypropylene hernia repair patches are better suited than the polytetrafluoroethylene hernia patches and vice versa for other applications. However, many applications find that none of the hernia patches of the prior art is entirely satisfactory.
U.S. Pat. No. 5,593,441 to Lichtenstein et al. addressed these drawbacks and provided a composite prosthesis for limiting the incident of postoperative adhesions. The composite included a mesh fabric with a barrier covering the mesh fabric to prevent exposure of the mesh fabric to areas of potential adhesion. The '441 patent discloses the use of polypropylene monofilament mesh fabric covered with a barrier layer, preferably formed of a sheet of silastic elastomer. The '441 patent contemplated replacing the silastic sheeting with microporous polypropylene sheeting, expanded PTFE, teflon mesh and oxidized, regenerated cellulose.
Parviz K. Amid and Irving L. Lichtenstein, coinventors on the '441 patent, followed the disclosures in the '441 application with an experimental evaluation of Lichtenstein's Journal of Biomedical Material Research Volume 28, pages 373-375 1994, entitled “Experimental Evaluation of New Composite Mesh with the Selective Property of Incorporation to the Abdominal Wall Without Adhering to the Intestines”. This study included testing polypropylene mesh laminated (completely attached on the peritoneal side) with unreinforced vulcanize silastic sheeting, as well as testing polypropylene mesh attached on the peritoneal side to the polypropylene sheeting in such a way that the polypropylene mesh and the polypropylene sheeting between the attachment locations were left unattached to allow free infiltration of collagen fibrous from the host tissue into the polypropylene mesh. The results indicated a less than successful result with the polypropylene mesh completely attached on the peritoneal side with the unreinforced vulcanized silastic sheeting. The results also suggested that the composite structure should be formed as a layer of porous material on one side attached by a series of parallel lines to a layer of nonporous material on the intestinal side for tissue infiltration of the host tissue to one side and to prevent adhesions on the other.
The '441 patent as well as the composite prosthesis suggested in the Amid and Lichtenstein article, result in relatively complex and expensive manufacturing procedures.
SUMMARY OF THE INVENTION
The object of my present invention is to overcome the aforementioned drawbacks of the prior art. A further object of my invention is to provide a universal, surgical mesh prosthesis which is easily adapted for a wide variety of surgical procedures. A further object of my invention is to provide a surgical mesh prosthesis which is easy to utilize and cost effective to manufacture.
The objects of my invention are achieved by providing a universal, surgical mesh prosthesis in the form of a foldable sheet which is particularly well adapted for hernia repair. The prosthesis includes a barrier layer formed of a material adapted to prevent biological tissue adherence thereto and a second material coupled to and extending from one surface of the barrier layer, the second material formed of a material adapted to promote biological tissue adherence thereto. The second material projects from the one surface of the barrier layer at a series of spaced locations. The second material may be formed of a polyolefin such as polypropylene, and the barrier layer may be formed of a fluoropolymer such as polytetrafluoroethylene. The second material may be attached to the barrier layer by various techniques.
The sheet of my present invention is adapted to be manipulated to an operative position to exhibit between 0-100% of the second material on an exterior of the sheet when in the operative position.
Several specific examples of distinct operations utilizing the universal, surgical mesh prosthesis of my invention are disclosed. For example, my invention may be utilized in a ventral hernia operation wherein the second material is prevented from contacting the abdominal viscera by the barrier layer. The universal, surgical mesh of my invention is folded to an operative position in which the abdominal viscera is positioned adjacent the barrier layer while the second material is positioned adjacent the abdominal wall muscles. In this type of hernia operation, the barrier layer should not form a permanent layer to prevent adhesions. It is more effective if a neo-peritoneal layer forms over the prosthesis with the neo-peritoneal layer serving as a natural membrane to prevent adhesions to the prosthesis. The present invention is constructed in a manner to promote the growth of a neo-peritoneal layer. Further, my invention is also particularly well adapted for inguinal hernia operations in which the barrier layer is positioned adjacent the spermatic cord and the second material is positioned adjacent muscle tissue when in the operative position. The specific uses are intended to be only examples of the various types of distinct operations to which my univer
Davol Inc.
Prebilic Paul B.
Wolf Greenfield & Sacks P.C.
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