F. E. Primus1 and H. W. Harris

….. FDA indications for biologic mesh The FDA requires products that will be classified as medical devices meet certain regulatory requirements based on the risk associated with their intended use. They are then stratified into classes I, II, or III, with class I having the lowest risk to public safety and class III having the highest [10]. This regulatory equirement, or 510(k) clearance, determines that a product either has (a) the same intended use and characteristics of a product already on the market or (b) the same use but different characteristics, while effectively showing that the different characteristics are as safe and/or effective as what already exists. Under most circumstances, clinical trials are not needed to meet these requirements [11]. However, to obtain FDA approval, the product must go through a premarket approval (PMA) process, which does require evidence from a human clinical trial documenting both safety and efficacy. In other words, clearance requires that a product be shown to be at least as good as what is already on the market, whereas approval requires proof that a product’s claims are accurate. The FDA views xenograft meshes as general surgical meshes, which are ‘‘intended to reinforce soft tissue or bone where weakness exists’’ [12]. They have been grouped as class II products, requiring them to undergo the 510(k) clearance process. In obtaining this clearance, xenografts are held to the ‘‘substantially equivalent’’ safety and efficacy threshold of what is already on the market. Interestingly, the FDA views allografts as human tissue for transplantation and not as medical devices. This distinction causes them to be regulated through the FDA’s Center for Biological Evaluation and Research [13], which has even fewer regulatory requirements than both the 510(k) and PMA processes.Essentially, this means that allografts have not needed the same burden of proof as xenografts to show safety and efficacy in order to be marketable as a general surgical mesh. In fact, allografts did not acquire FDA approval nor clearance to be marketed or used as a surgical mesh at all. So in summary, whereas the xenografts have obtained clearance to be used as a general surgical mesh where the allografts have not, neither has been cleared nor approved for use in contaminated settings. Nevertheless, both xenografts and allografts are being used as surgical meshes and specifically, as surgical meshes in contaminated settings.