PREOPERATIVE FACIAL-NERVE STUDIES PREDICT PARESIS FOLLOWING CEREBELLOPONTINE ANGLE SURGERY

Facial paresis or paralysis following resection of cerebellopontine an gle tumors can occur despite intraoperative cranial nerve monitoring. In an attempt to identify preoperatively those patients at greatest ri sk for postoperative facial nerve dysfunction, we have prospectively e valuated 30 patients with clinically normal facial function using preo perative facial nerve conduction, electromyography, and the blink refl ex. Surgical approach, tumor size, tumor histological, and postoperati ve facial nerve function were correlated with the preoperative electro physiologic data to determine the utility of preoperative facial nerve tests as predictors of postoperative facial nerve function. Nineteen patients (Group I)had normal preoperative facial nerve studies, while II patients (Group 2) had abnormal results. Fourteen patients in Group 1 were Grade I immediately after surgery, and five were Grade II. All 19 patients were Grade I at 6 months. The 11 patients in Group 2 had immediate postoperative facial nerve function graded as follows: I, th ree patients. II: five patients; III, one patient; VI; two patients. A fter 6 months, facial nerve function was graded as follows: I, six pat ients; II, two patients; III one patient; VI, two patients. The blink reflex was the single most accurate predictor of facial nerve involvem ent preoperatively.