Clinical use of an improved processed bovine cartilage for contour defects

We have combined irradiation with a new chemical processing to cross-link the collagen of bovine cartilage, thereby stabilizing the collagen molecule and rendering it antigenically inert and dimensionally stable. Irradiated allograft cartilage has been successfully used for repair of facial contour defects since the 1950s, but the usefulness of this material has been limited by lack of availability. Chemically processed bovine cartilage had previously been used, but the implants were subject to slow degradation and were usually absorbed completely within 2 years. After first testing this new material on rabbits and primates, we experimentally placed 40 implants in 28 patients over the course of 3 years. Thirty-six of these implants have survived without change in size or shape for more than 1 year, 20 of these for more than 2 years. In 2 cases, full or partial absorption of the implants occurred secondary to operative infection. In another case 2 implants were lost, probably because of infection. In the absence of infection, neither primary nor second-set provocative implant tests of processed irradiated bovine cartilage elicit any foreign body reaction, either cellular or noncellular. The material performs well aesthetically and appears to undergo no absorption during the 1- to 4-year follow-up observed to date. The period of follow-up of 1 to 4 years reported here may be insufficient to reach a definitive conclusion that no very slow absorption of processed irradiated bovine cartilage implants occurs. It is noteworthy, however, that half of the implants have already survived with no apparent absorption for a period longer than that at which nonirradiated bovine cartilage implants would be expected to have been absorbed completely. This result suggests that any absorption that may occur, other than that associated with infection, takes place at a rate so slow as to be unobservable in anything but the very long run. We believe that this evidence of the long-term survivability of processed irradiated bovine cartilage, together with its excellent performance aesthetically and the fact that it can be made readily available commercially, indicates that it may represent an effective implant material for repair of contour defects.