distinct tendency to shrink and must, therefore, be of sufficient size on insertion (Probst 1986). The grafts are fixed with fibrin glue and sutures.

There is a tremendous amount of clinical and experimental knowledge about autogenous fascia transplantation. All results indicate that free autogenous fascial tissue grafts (fascia lata, temporalis fascia) remain vital (Probst 1971, 1986). Blood supply is assured by direct spontaneous anastomosis between the vessels of the graft and those of the local tissues.

9.2.1.2  Autogenous Muscle Grafts

(Probst 1986; Stoll 1993)

In contrast to fascia grafts, autogenous muscle grafts taken from the frontalis, temporalis, or quadriceps femoris muscles share the disadvantageous tendency to shrink and cicatrize and are afflicted with the problems of other free transplants. Similar to autogenous bone grafts, autogenous muscle grafts must be surrounded by vital tissue in order to heal (Stoll 1993) (Fig. 9.1).

9.2.1.3  Pericranium Flap/Graft (Kessel et al. 1971; Jackson et al. 1986; Imhof 2000)

The vital and vasularized pericranial flap is available in a variety of sizes and because of its adaptability and vitality has become standard in skull base reconstruction.

Adjacent sections of pericranium may be used as nonvascularized tissue patches (Price et al. 1988).

9.2.2  Allogeneic Transplants

9.2.2.1  Lyophilized Dura

Freeze-dried lyophilized human dura, which was frequently used in the past, is only rarely used today due to the risk of slow virus infection [Jakob-Creutzfeld disease, bovine spongiform encephalopathy (MartinezLage et al. 1993; Lane et al. 1994; Christmann 2003)].

9.2.2.2  Collagenous Compounds

Today there is an increased availability of products based on collagen structural proteins. These compounds are derived from both humans and animals. Chemical processing can alter the connective tissue structures to such an extent that a mere acellular and antigen-free collagen frame remains (Chaplin et al. 1999). As a result, membranes exist which are exclusively composed of collagen fibrils or collagen-laminated substrates — e.g., polyglactin — without bearing the relatively high infectious risks of nontreated alloor xenogenic transplants (San-Galli et al. 1992).