NERVE REGENERATION IN A BONY BED - VASCULARIZED VERSUS NONVASCULARIZED NERVE GRAFTS

In a rabbit model, regeneration of the intratemporal facial nerve was studied as vascularized and nonvascularized nerve grafts. Fifteen New Zealand white rabbits weighing 4 to 4.5 kg were used. A 1-cm gap was c reated in the intratemporal facial nerve. In the vascularized nerve gr aft group (group 1), the facial nerve was repaired with a vascularized median nerve graft (n = 6), while in the nonvascularized nerve graft group (group 2), the median nerve was used as a nonvascularized graft (n = 6). In group 3, the facial nerve gap was left unrepaired (n = 3). At 3 months postoperatively, electrophysiologic testing, morphologic nerve study, and morphometric muscle analysis were performed. Although the mean numerical values of axonal counting, nerve conduction, and m orphometric muscle study results were slightly better in the vasculari zed nerve graft group, the differences between the two grafted groups were not statistically significant (p > 0.05). Morphometric nerve anal ysis, i. e., axon diameter and myelin sheath thickness, showed signifi cant differences in nerve regeneration between the two groups (p < 0.0 5). These results suggest that a bony bed is not optimal for neovascul arization of a nerve graft. We conclude that vascularized nerve grafts are superior to nonvascularized nerve grafts when nerve regeneration occurs in a bony recipient bed. This might be of clinical importance i n the repair of facial nerve lesions within the temporal bone.