Let’s take a closer look at one of the Davol patents, which provides the “blueprint” for the Kugel Mesh Hernia Prosthesis (Canadian Patent CA 2 357 020). A brief review of Davol’s patent shows that the oval shaped Kugel Patch is made from a mesh that will not dissolve, and that it has a flexible ring fastened around the edge of the oval mesh to give it shape. The ring material is supposed to dissolve (resorb) over time, leaving the flexible mesh in place to act as an abdominal wall support. Once in place, the mesh portion of the Kugel Patch adapts to the convex shape of the abdomen.
The flexible ring portion of the Kugel Patch has “memory recoil.” Because of the ring’s flexibility, a surgeon can compress the patch, insert it trough a small incision and expect it to spring back into its original shape. This desirable springing back feature separated the Davol Kugel Patch from its competition, making it less prone to folding back on itself after placement, like other patches, and forming a weaker support.
In addition, Davol scientists designed the flexible ring with an interruption that left the ring open, exposing the mesh for a small distance without ring support. This gap in the ring would allow a surgeon to place the exposed section of the Kugel Patch over the femoral vein, without compressing it under rigid ring material.
Unfortunately, the memory recall ring material can break under the stress of the operation, leading to bowel perforations (rupture) and/or abnormal connections between the intestine and other organs (fistulae). While a surgeon might place the Kugel Patch successfully, it might break over time, causing persistent abdominal pain, fever, and tenderness at the implant site http://www.fda.gov/cdrh/recalls/recall-122205.html
After notifying doctors and hospitals on March 24, 2006 about recalled products and instructing them further concerning proper insertion, Davol then notified U.S. customers of the initial recall in December 2007.