Effect of cervical sympathetic ganglionectomy on facial nerve reconstruction using polyglycolic acid-collagen tubes.

Abstract

A polyglycolic acid-collagen (PGA-c) tube was used as an artificial nerve guide during facial nerve reconstruction performed in a canine model of stellate ganglion block (SGB). The model was generated using a cervical sympathetic ganglionectomy. We evaluated the effects of blood flow on nerve regeneration. First, we resected the left cervical sympathetic ganglion in beagles (n=6). We assessed buccal mucosal blood flow and nasal skin temperatures once per week for 12weeks and Horner's sign 2, 4, and 6months after resection. We compared these values to those measured prior to resection. Blood flow was increased for 6-11weeks, but sympathetic control remained blocked after 6months. Second, we divided beagles into 3 groups: resection models (negative control), from which 7mm of the left facial nerve buccal branch was resected (n=5); reconstruction models, which underwent nerve reconstruction using PGA-c tubes (n=6); and SGB+reconstruction models, which underwent a left cervical sympathetic ganglionectomy immediately after reconstruction (n=6). The right side of the face served as control (n=17). Nerve regeneration was significantly greater in the SGB+reconstruction model dogs than in the reconstruction model dogs, as measured by both electrophysiological and morphological analyses at postoperative week 12. In particular, motor nerve conduction velocity was increased approximately 2-fold (p=0.018). We were able to generate an SGB model with long-term increased blood flow facilitated by the promotion of facial nerve regeneration by PGA-c tubes.