RAPID INTRAOPERATIVE FACIAL-NERVE EXPANSION

The repair of nerve length defect presents a reconstructive challenge after trauma and oncologic resection. This study examined rapid intrao perative nerve expansion as a method of repairing nerve length defects with the cat facial nerve model. We compared expanded nerves with gra fted nerves and intact nerves 1 year after repair using the criteria o f gross function (symmetry and blink reflex according to a modified Ho use scale), electromyography thresholds, nerve-conduction velocity, mo rphology, and axon count. Three of the five expanded nerves regenerate d, and all of the grafted nerves regenerated. Functional results were similar for the regenerated expanded and the grafted facial nerves, an d both methods achieved an equivalent level of function. The facial ne rves of the regenerated expanded group, grafted group, and intact grou p had mean electromyography thresholds of 132 mV, 98 mV, and 134 mV, r espectively, and mean conduction velocities of 48.3 mg/second, 47.9 m/ second, and 44.7 m/second, respectively. Morphologic examination of al l five expanded nerves immediately offer the expansion process reveale d an intact fascicular structure. However, 1 year after excision of th e expanded segment and repair, only three of the five nerves regenerat ed. Axon count at 1 year was as follows: 404 for the regenerated expan ded nerves, 449 for the grafted nerves, and 403 for the intact nerves. The potential advantages of rapid intraoperative nerve expansion over nerve grafting for the repair of nerve gap defects include a single s uture line and absence of donor site morbidity. This pilot study demon strates that rapid intraoperative nerve expansion and regeneration is possible and can be used to repair a nerve length deficit. The develop ment of a rapid and reliable method of intraoperative nerve expansion deserves further study.