Treatment of Lateral Skull Base and Posterior Cranial Fossa Lesions Utilizing the Extended Middle Cranial Fossa Approach

OBJECTIVE: Define the indications and outcomes for subjects undergoing treatment utilizing the extended middle cranial fossa approach (EMCF). STUDY DESIGN: Retrospective records review. SETTING: University-based tertiary referral center. PATIENTS: Subjects undergoing treatment of posterior cranial fossa (PCF) lesions. INTERVENTION(S): EMCF exposure and treatment of the indicating PCF lesion. MAIN OUTCOME MEASURE(S): Demographic, audiometric, and cranial nerve functioning variables were assessed. RESULTS: Thirty-five subjects who underwent an EMCF exposure were identified over a 12-year period. The most common indication was meningioma (18; 51%) followed by schwannomas (six, 17%), and vascular lesions (five, 14%). Preoperative cranial nerve complaints were common (32, 94%) as were objective cranial nerve abnormalities on physical examination (21; 60%). Preoperative audiometric data from subjects with hearing demonstrated good functioning including pure-tone average (PTA) (21.7 ± 15.6 dB HL) and word understanding scores (95.1 ± 7.4%). Most (34, 97%) subjects had intact facial nerve function. The average length of stay was 11.6 days (median = 9). Cranial neuropathies were common postoperatively with 27 (79%) subjects demonstrating some objective cranial nerve dysfunction, the most common of which was trigeminal nerve hypesthesia (21, 61.7%). Subjects with identifiable pre- and postoperative audiometric data and preoperative hearing demonstrated small declines in the four-tone average (16.2 dB) and word recognition scores (22.4%). Two subjects (6%) had new profound hearing loss postoperatively. CONCLUSIONS: The EMCF approach can provide safe and effective exposure of the anterior PCF.