Repair of the facial nerve using freeze-thawed muscle autografts. A surgical model in the sheep.

In five sheep, repair of the right facial nerve in the preparotid region was undertaken using freeze-thawed muscle autografts aligned coaxially in the nerve gap. The sheep were reviewed at 240 days. Nerve conduction velocities were measured in the distal buccal nerve after stimulation proximal to the repair site and compared with an equivalent site on the normal side. Although mean peak conduction velocities were reduced on the repaired side, electrophysiologic evidence showed regeneration in all five cases. Normal and repaired nerves were retrieved for histologic study. Anatomic indices of regeneration were compared using morphometric techniques. As seen in other methods of nerve repair, axon and fiber diameters with normal myelination were reduced on the operated-on side. The muscle graft thus compares favorably with other surgical techniques over the gap lengths considered herein.