Microsurgical treatment of large acoustic neurinoma

Objective To discuss microsurgical experience for transsuboccipital retrosigmoid sinus approach of large acoustic neuronomas,and improve the rate of tumor removing,and facial nerve and auditory nerve preserving Methods A retrospective analysis of 39 patients with acoustic neuronomas which were more than 4 cm in diameter were treated by microsurgery between January 1994 and December 2000 Tumor's excision was performed by transsuboccipital retrosigmoid sinus approach The surgical main points of transsuboccipital retrosigmoid sinus approach,and their experience of total removal,and rate of facial nerve and auditory nerve preservation were described Results The tumors were totally removed microsurgically in 34 patients,the total removal rate was 87 2%,and subtotal removal in 5 patients Facial nerve was anatomically preserved in 31 cases,the rate of facial nerve preservation was 79 5%,but the function of facial nerve was recovered in 22 cases (56 4%) The auditory nerve was preserved anatomically in 15 cases (38 5%) and functionally in 7 cases (17 95%) Conclusions An minimally invasive microsurgical treatment are crucial for increasing a satisfactory living quality of the patients It is considered that the total removal rate of tumor,the preservative rate of facial nerve and auditory depend upon microsurgical technique and intraoperative facial nerve monitoring in acoustic neuromas surgery