Extended middle fossa surgery for meningiomas within or at the internal auditory canal.

Abstract

Objective: To show the clinical outcome in patients with meningioma within or at the internal auditory canal (IAC) operated on by the extended middle cranial fossa approach.

Study design: Retrospective case review.

Setting: A tertiary referral center.

Patients: Twelve patients, 9 women and 3 men, whose ages ranged from 37 to 70 years (mean 57 years). One tumor was entirely intracanalicular, 5 had an intra-extracanalicular growth, 3 were centered at the posterior porus lip, and 3 tumors were localized in the midpetrosal region with spread into the IAC.

Intervention: Extended middle cranial fossa approach.

Main outcome measures: Magnetic resonance imaging and computed tomography were used for follow-up and reevaluation of the operative sites. Facial nerve function and hearing were examined.

Results: Complete resection was achieved in 10 (83%) of 12 patients. The retrosigmoid approach was necessary to complete tumor resection in one patient, and in another, partial resection was done because of the en plaque type of tumor growth. There was one unexpected recurrence. All patients retained normal or near-normal facial nerve function postoperatively. Three patients were deaf before surgery, and preoperative hearing level was preserved in 42%.

Conclusions: Attempted hearing preservation surgery is justified in patients with small tumors and preserved hearing, because tumor exposure and safety of resection are comparable with that of hearing-destructive procedures. Lateral extension of the tumor to the fundus does not prevent complete resection with preservation of function, and elective bone resections beyond the visible tumor margins seem not to substantially influence the tumor recurrence rates.