Surgical results in 254 cases of acoustic tumors

Surgical results in 254 cases of acoustic tumors operated on by the same neurosurgeon (T.S.) were reported. Based on the tumor size in the CP-angle cistern, cases were divided into 4 groups: Group S: AT<1 cm, Group M: 1 cm≦AT<2 cm, Group L: 2 cm≦AT<4 cm, Group G: 4 cm≦AT. The number of cases for each group was 11, 60, 139 and 44, respectively. Results: The tumors were totally or subtotally removed in all cases in both Group S and Group M. However, in 3% of the cases in Group L and 11% of the cases in Group G the tumors were partially removed for the preservation of hearing. Anatomical preservation of the facial nerve was achieved in 96.8% (243/251) of the patients. As to the facial nerve function, the rate of House-Brackmann Grade 1 & 2 in Group S was 91% at discharge, 91% at 6 months after the operation and 100% at 1 year after the operation. It was 83%, 96% and 96% in Group M, 61%, 81% and 91% in Group L, 63%, 74% and 78% in Group G, respectively. Thus, the facial nerve function improved with time in cases where the facial nerve were anatomically preserved. Useful hearing was preserved in 90.0% (9/10) of the patients in Group S, 59.0% (23/39) of Group M, and 39.6% (21/53) of Group L. Even in Group G, useful hearing was preserved in 2 out of 3 pts. Over all, the rate of useful hearing preservation was 52.4% (55/105). Conclusion: Both facial nerve function and useful hearing can be preserved well in tumors smaller than 2 cm in diameter.