Repair of the facial nerve in the cerebellopontine angle using freeze-thawed skeletal muscle autografts. An experimental surgical study in the sheep.

Six adult blackface sheep underwent repair of the transected facial nerve in the cerebellopontine angle using short freeze-thawed muscle autografts. A typical facial palsy was observed on the side of the intervention immediately after operation. The sheep were allowed to recover for one year by which time clinical observation showed a complete recovery of the facial palsy in 5 sheep and a partial recovery in the remaining sheep. Under general anaesthesia function of the repaired VIIth nerve and the normal contralateral facial nerve were assessed using electrophysiological stimulating and recording techniques. These studies showed restoration of facial nerve continuity to have taken place with functional reinnervation of target facial muscles. Electrophysiological indices of nerve function were consistent with those expected after repair of any peripheral nerve. Morphometric study of the nerves after their removal showed structural changes which though quantitatively different from those of normal nerve were consistent with those seen in other sites and studies where nerves have been repaired. This technique is discussed as a possible treatment for facial nerves whose continuity is disrupted during the removal of cerebellopontine angle tumours.