Management of Vestibular Schwannoma, Importance of the Tumor Size

Object: The authors evaluated the outcome of radical microsurgery via an osteoblastic retrosigmoid method in a consecutive series of patients with vestibular schwannomas (VSs), with consideration of the tumor size.

Methods: The authors performed a retrospective study of 424 patients with VSs from 1–3 cm in maximal diameter during a 5-year period. Those in group A had tumors from 1–2 cm in diameter. This group was compared with a matched group of 167 patients with VSs that were from 2–3 cm in diameter (group B). All patients were operated on by the senior surgeon.

Results: The mean tumor size in group A was 1.7 cm and in group B was 2.6 cm. The anatomical integrity of the facial nerve was preserved in 100% of patients in both groups A and B. At last follow-up, 94% of the patients in group A had excellent (grade 1 H&B) and 6 % had good facial nerve. Also, in 51% of patients in group A, preoperative hearing level was preserved. Newly developed lower cranial nerve dysfunction occurred in 0% patients. A CSF leak developed in 2% of patients. Compared with group B, a significant difference was found in the rates of the following parameters: excellent facial nerve function (H&B grade I) (78% in group B) and preservation of preoperative hearing (34% in group B) (P < 0.05). The perioperative mortality rate was 0%, and the surgery-related complication rate was the same in both groups.

Conclusions: Any change in the tumor size significantly correlates with postoperative outcome of facial and hearing preservation.