Brain-derived neurotrophic factor-enriched collagen tubule as a substitutefor autologous nerve grafts

Background: Autologous nerve interposition grafts are frequently harvested by head and neck sure;eons. The sacrifice of these donor nerves guarantees sc,me degree of morbidity, including sensory loss, additional incision site s with associated potential complications, and prolonged operative time. An alternative to autologous nerve grafting is,: therefore, desirable. Objective: To determine ifa collagen tubule (CT) filled with either a plain collagen gel or a brain-derived neurotrophic factor (BDNF)-enriched collag en gel could be used to achieve functional and histologic outcomes equivale nt to an autologous nerve graft in bridging a 15-mm nerve gap in the rabbit facial nerve. Design: A prospective, randomized, blinded animal study with a control grou p. Methods: Thirty rabbit facial nerves were resected (15-mm segments) to crea te nerve gaps. The gaps were bridged using 1 of 3 methods, assigned randoml y: a reversed facial nerve (control), a collagen gel-filled CT, or a BDNF-e nriched collagen gel-filled CT. The animals were evaluated after 6 weeks in a blinded fashion for functional nerve recovery, axon count, and axonal di ameter. Results: There were no significant differences between the autologous nerve graft group, the collagen gel-filled CT group, or the BDNF-enriched collag en gel-filled CT group (n=10 for each group) for functional nerve recovery (P=.94). The mean axon count and the mean axonal diameter were highest in t he BDNF-enriched collagen gel-filled CT group, but these differences failed to reach statistical significance (P=.18 and.96, respectively). Conclusions: Collagen tubules filled with BDNF-enriched collagen gel appear to be at least as good as autologous nerve grafts for bridging short facia l nerve gaps. Larger experimental studies are warranted to determine if cli nical trials are justified.