Facial nerve regeneration with atelocollagen nerve grafts

Abstract

Facial nerve defects are frequently produced as complications of surgery or due to trauma. In such cases, the facial nerve is repaired with an autograft. However, this procedure has many disadvantages, including donor site morbidity, sensory loss, and incomplete regeneration. This study evaluated the functional and histological regeneration of the facial nerve in adult guinea pigs after repair with autogenous or collagen nerve grafts, with or without laminin and bFGF. The artificial nerve is made of an atelocollagen tube containing atelocollagen fiber and sponge (NIPRO, Japan). The facial nerve was resected (10-mm segments) to create nerve gaps in four groups of animals in order to compare the histological and functional outcomes: Group A (n=6): autologous nerve interposition graft, Group B (n=6): collagen nerve guide, Group C (n=3): collagen nerve guide with bFGF, and Group D (n=3): collagen nerve guide with laminin. Electron microscopical and electrophysiological examinations were performed 6 weeks after the nerve grafts. The results of conduction velocity tests showed excellent nerve regeneration in Groups A and C. Regenerated nerve fibers were observed in both groups using electron microscopy, and the axonal diameter and myelinated nerve sheath were thicker in Groups A and C than that in the other groups. The results of this study suggest that an atelocollagen nerve guide filled with bFGF is at least as good as autologous nerve grafts for bridging 10mm facial nerve gaps. However, further research is necessary before this procedure becomes widespread.