Trigeminal schwannomas: a report of 42 cases and review of the relevant surgical approaches.

This study aims to achieve the complete removal of trigeminal schwannoma (TS) while preserving cranial nerve function. We focused on the outcomes of different surgical approaches and address the contributions of different operative techniques. Forty-two TS cases, treated surgically in Qilu Hospital during a 12-year period, were reviewed and analyzed. There were 18 males and 24 females who were classified into four groups: type A (11 cases, 26%), type B (10 cases, 24%), type C (17 cases, 40%), and type D (4 cases, 10%). Various surgical approaches were applied accordingly. Surgical outcome and cranial nerve function were the criteria used to judge different surgical groups. The conventional approach was performed in 20 cases; the skull base approach was performed in 22 cases. Total and near-total resection was achieved in 80% of conventional cases and in 100% of skull base cases (chi(2)=4.86, P<0.05). Total resection was achieved in 81.5% of non-cavernous involvement cases and in 40% of cavernous involvement cases (chi(2)=7.47, P<0.05). Cranial nerve deficits were improved or unchanged after the operation in most cases; there was no significant difference between the conventional (76.9%) and skull base (87.5%) groups (chi(2)=0.56, P>0.05). The selection of operative approach should be based on the developmental patterns of the tumor. In comparison to the conventional approach, the skull base approach provides better exposure of the tumors and increases the frequency of total and near-total/partial resections. Cavernous sinus involvement was the major impediment to total removal of the trigeminal schwannomas. Treatment always aims for total tumor resection; preservation or improvement of cranial nerve function can be achieved in most cases.