Clinical Features and Comparison of the Results according to Surgical Methods in Patients with Intrameatal Vestibular Schwannoma

Kim, Jong Yang; Chung, Jong Woo; Lee, Kwang Sun

Abstract

BACKGROUND AND OBJECTIVES
Modern imaging and surgical techniques have made intrameatal vestibular schwannoma (IMVS) surgery safe and have allowed for good outcomes with respect to facial nerve function and hearing outcome. This study aimed to analyze clinical features and to compare the results of the middle fossa approach (MFA) and translabyrinthine approach (TLA) used during IMVS surgery.
SUBJECTS AND METHOD
We reviewed retrospectively 10 patients who were operated for IMVS from November 1995 to May 2005. This study analyzed chief complaint, size of tumor, audiological studies, caloric test, imaging study, and treatment modality.
RESULTS
The main symptom for IMVS patients is vertigo. But, in our study, patients having only vertigo was rare ; most cases had vertigo with tinnitus or hearing disturbance. Patients with vertigo and tinnitus had mild hearing disturbance in PTA and unilateral weakness in the Caloric test. In terms of mean operation time, it took 7.5 hours in MFA and 4 hours in TLA. Postoperative hearing loss and facial nerve palsy occurred in early MFA operation cases. With respect to facial nerve function, the MF approach group had a higher rate of development of facial neuropathy than did the TL approach group.
CONCLUSION
We think patients with vertigo and tinnitus will progress to hearing loss. We should suspect IMVS if patients complain of vertigo and tinnitus. But, further evaluation should be needed. If postoperative hearing preservation is not important, the TLA technique has made IMVS surgery safe and has allowed for good outcomes with respect to facial nerve function preservation. To use the MFA method, otolaryngologic surgeons need more direct and indirect experiences, considering the low incidence of acoustic schwannoma surgery and that the MFA method requires longer mean operation time than TLA.