Impact of fundal extension on hearing after surgery for vestibular schwannomas.

OBJECTIVE

To compare hearing preservation after surgery for intracanalicular vestibular schwannomas with or without fundal extension.

STUDY DESIGN

Retrospective chart review.

PATIENTS

Patients with intracanalicular tumors (≤ 10-m maximal dimension) undergoing retrosigmoid craniotomy between 2001 and 2010.

INTERVENTION

Preoperative and postoperative audiograms, preoperative magnetic resonance imaging, and operative reports were reviewed.

MAIN OUTCOME MEASURES

Preoperative and postoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery classification).

RESULTS

Complete data for 53 patients (27 female and 24 male subjects, sex was not recorded for 2 patients) meeting selection criteria was available. Fundal involvement was identified in 39 (73.6%) of the 53 patients. The remaining 14 patients did not have tumor with fundal extension (26.4%). Average tumor size for patients with fundal extension (+FE) was 6.9 ± 2.2 mm and without fundal extension (-FE) was 8.2 ± 1.9 mm (p = 0.05, Student's t test). Average preoperative speech discrimination score for the entire study was 90.5 ± 11.8 (n = 53). After retrosigmoid approach for tumor resection, 79% of patients (42/53) had preserved hearing defined as American Academy of Otolaryngology-Head and Neck Surgery class A, B, or C. Average postoperative speech discrimination score for these patients was 89.3 ± 12.1, and average postoperative pure-tone average was 35.9 ± 9.1%. Eighty-five percent (33/39) of +FE patients had preserved hearing (class A, B, or C). In contrast, 64% (9/14) of -FE patients had hearing preserved (class A, B, or C; Fisher's exact test, p = 0.034).

CONCLUSION

Hearing preservation rate after retrosigmoid craniotomy for intracanalicular vestibular schwannomas may be superior for tumors with fundal extension compared with tumors that do not extend to the fundus.