Kobe Journal of Medical Sciences, 2000

LONG-TERM RESULTS OF FACIAL NERVE FUNCTION AFTER ACOUSTIC NEUROMA SURGERY -CLINICAL BENEFIT OF INTRAOPERATIVE FACIAL NERVE MONITORING-.

Masashi MORIKAWA, Norihiko TAMAKI, Tatsuya NAGASHIMA, and Yasuhiko MOTOOKA 

Department of Neurosurgery, Kobe University School of Medicine 

Kobe J. Med. Sci. 46, 113-124, June 2000

AB: The goals in acoustic neuroma surgery should be the total removal of tumor and preservation of facial nerve function. The aim of this study is to establish the benefit of intraoperative monitoring for the total removal of tumor and the long-term result of facial nerve function after surgery. Thirty-two patients, who were operated on between 1985 and 1995, were divided into two groups: an unmonitored (n=14) and a monitored (n=18) group. Postoperative facial nerve function was followed by a modified House-Brackmann grading (H&B) immediately (initial), and at I week, I month, 6 months and 1 year (final) after surgery. A final H&B grade of I/II was taken as the preservation of facial nerve function. Facial nerves were preserved anatomically in all cases. A total tumor removal was accomplished in 21% of unmonitored group and in 72% of monitored group patients. Final H&B (‡T/‡U) was achieved in 36'% of unmonitored group and in 83% of monitored group patients. All 9 patients with initial H&B (1/ll) had final H&B (‡T/‡U). None of 5 patients with initial H&B (V/VI) had final H&B (‡T/‡U). However, 3 patients showed late-recovery of facial weakness at 6 months after surgery. Eighteen patients with initial H&B (III/IV) had various degrees of final facial weakness. Among them, 12 patients showed early-recovery at I month after surgery. In conclusion, facial nerve monitoring during acoustic neuroma surgery is useful to improve the rates of total removal of tumor and functional preservation of facial nerve. We can expect final degrees of facial weakness by initial degrees in conjunction with sequential changes in postoperative facial weakness.