Middle Fossa Approach for Resection of Vestibular Schwannomas: Surgical Results in the Radiosurgery Era

Background: The management of small, intracanalicular vestibular schwanommas (VS) in patients with serviceable hearing is controversial, with many authors advocating for radiosurgery. We present our experience with resection of these tumors using the middle fossa approach.

Methods: We reviewed the records of all patients presenting to the University of Cincinnati Medical Center between January 2006 and July 2015 for resection of VS using a middle fossa approach. Pre and post-operative hearing was assessed using the American Association of Otolaryngology-Head and Neck Surgery classification. Facial nerve function was assessed using the House-Brackmann (HB) grading system. The Mann-Whitney u-test and chi-square tests were used to compare groups with and without preserved hearing; significance was defined as p < 0.05.

Results: A total of 46 patients met our inclusion criteria and were followed for a median time of 14 months (interquartile range: 5–25 months). Twenty-four were women and 22 were men. The median age was 50.5 years (IQR: 40–59 years). The median tumor size was 10 mm (IQR: 6– 13 mm). Preoperative hearing grades were as follows: 57% Class A, 30% Class B, 4% Class C, and 11% Class D. Serviceable hearing (AAO-HNS Class A or B) was preserved at last follow-up in 61% of patients (52% Class A, 48% Class B post-operatively). Age, tumor size, year of surgery, smoking status, history of diabetes mellitus, and pre-operative hearing class did not differ significantly between those patients with hearing preservation versus loss of serviceable hearing. Post-operatively, 8 patients (17%) developed new HB grade 2 facial weakness, and 1 patient (2%) developed HB grade 4 weakness. Gross total resection without recurrence was achieved in all but one case, in which progression was successfully treated with radiosurgery. Four patients (9%) developed cerebrospinal fluid leaks that all resolved with temporary lumbar drain placement. There were no other noted complications.

Conclusions: In our experience, the middle fossa approach for small vestibular schwannomas offers the ability to achieve complete surgical resection with excellent rates of hearing preservation. Our results are similar to previous middle fossa series, and better than those quoted in some radiosurgical literature. Facial nerve morbidity and complication rates are minimal. We believe that surgical resection using a middle fossa approach should be the initial treatment of choice for these tumors.