Symposium: management of tumors of the parotid gland. III. Management of the facial nerve.

The facial nerve is protected in parotid surgery by finding the main trunk first and peripherally dissecting free the branches. The most constant landmark is the groove between the mastoid and the bony ear canal. Wide exposure of this groove should be obtained without "tunnelling." The thick (2-3 mm) white trunk is dissected forward using the electric stimulator before cutting parotid tissue. Nerve injury is more common in the peripheral branches. Nerve location in recurrent parotid tumors is more difficult. The main trunk may be found more posteriorly than in the previous surgery, but often peripheral branches must be identified crossing the masseter, facial vessels, or the parotid duct; retrograde dissection to the trunk follows. For proven invading malignancy, the trunk or branches may be sacrificed, but immediate grafting should be attempted usually with the greater auricular nerve.