Extension of neuromuscular pedicles and direct nerve implants in the rabbit.

Extension of neuromuscular pedicles and direct nerve implants was investigated in ten rabbits. All rabbits underwent facial nerve resection bilaterally. In five rabbits a neuromuscular pedicle, based on the ansa cervicalis nerve, was implanted into the denervated mentalis muscle unilaterally. On the opposite side, reinnervation was attempted using a neuromuscular pedicle with an interposed nerve graft. In the other five rabbits, reinnervation was attempted using a direct nerve implant on one side and a direct nerve implant extended with a nerve graft on the opposite side. Evoked electromyographic muscle tension and histologic studies were used to evaluate reinnervation. Functional neuromuscular units were consistently produced with neuromuscular pedicles, direct nerve implants, and extended direct nerve implants, while extended neuromuscular pedicles failed to produce detectable reinnervation.