Clinical Operative Concepts

Adherence characteristics to the facial nerve at the tumor interface can in most instances clinically separate benign from malignant pathology. The adherent facial nerve branches readily elevate in the presence of benign neoplasms. Inflammatory masses may not separate easily, but there is usually more associated bleeding than in similarly adherent malignant neoplasms.

Functioning facial nerves are retained in the presence of any grade malignancy, including nerve encasement by tumor. The nerve is meticulously separated from tumor circumferentially if necessary using the operative microscope. Although the latter is clearly controversial, all advanced grade malignancy will require adjunct radiotherapy. There are no confirmatory data to suggest leaving microscopic disease on nerve increases local recurrence when postoperative radiation therapy is administered.7 Although there is initial paresis uniformly in most such instances, there is a return to full facial nerve function if such is present preoperatively. With this approach, there is an obvious decrease in morbidity.

The facial nerve is resected when function is impaired pre-operatively. In such cases, frozen section is performed on the cut nerve endings, both proximal and distal, to obtain negative margins when feasible. Immediate nerve grafting is performed when tumor-free margins are obtained, as postoperative radiotherapy does not adversely affect graft reinnervation. If a facial nerve is positive at the first genu, further resection has no survival advantage and an intracranial resection has significantly increased morbidity. In the latter setting, the facial nerve is not grafted.

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