Risk-Benefit Analysis of Using the Middle Fossa Approach for Acoustic Neuromas With >10 mm Cerebellopontine Angle Component

Objectives To evaluate hearing preservation and facial nerve (FN) outcome in the middle fossa (MF) approach for acoustic neuromas with a cerebellopontine angle (CPA) component >10 mm. Study Design Retrospective review of 193 patients. Patient Population Patients were grouped according to tumor size: intracanalicular tumors (IC; 64), 1 to 9 mm CPA extension (42), and 10 to 18 mm CPA extension (47). Additionally, a group of 40 patients (tumor size 10–18 mm CPA extension) who had undergone a translabyrinthine (TL) approach was studied to assess comparative FN outcome. Hearing and FN function were measured 1 year postoperatively. We defined the success at functional hearing preservation as AAO–HNS class B or better and good FN outcome as House‐Brackmann grade II or better. Results For IC tumors and those with up to 9‐mm CPA extension, there was no significant difference in the rate of functional hearing preservation (62.2% vs. 63.1%, P = .931) and good FN outcome (93.7% vs. 97.6%, P = .358). For tumors of 10‐ to 18‐mm CPA extension, the rate of hearing preservation (34%) was lower than the other groups (P = .006 and P = .009). In this group, the rate of good FN outcome was lower compared with the IC and 1‐ to 9‐mm tumors (80.8% vs. 93.7%, P = .037 and 97.6%, P = .012). The rate of good FN outcome following the TL approach in a comparable cohort of patients was 100% (P = .003 in comparison with 10–18 mm tumor resected with the MF approach). Conclusions When considering surgical options, patients with >10‐mm tumors should be advised that choosing the MF approach for hearing preservation carries a somewhat higher risk of persistent FN dysfunction.