Use of a Reciprocating Suction Microdebrider for Resection via the Middle Fossa Approach of Acoustic Neuromas with Significant Cerebellopontine Angle Extension

Introduction: Resection of acoustic neuromas via the middle fossa route is technically challenging, especially as tumor size increases with extension into the cerebellopontine angle. The Myriad reciprocating suction microdébrider enables rapid and safe tumor debulking through a very limited corridor of access. When used as an adjunct to traditional techniques, this device allows larger tumors to be resected via this route with excellent facial nerve and hearing outcomes.

Methods: All operations were carried out by an operative team consisting of a neuro-otologist and a neurosurgeon. The middle fossa approach was used for small, mostly intracanalicular acoustic neuromas in patients with good preoperative hearing. Thirteen consecutive operations using the Myriad reciprocating suction microdebrider via the middle fossa route between April and October 2010 are reported. This device was used exclusively for resection of tumors with significant cerebellopontine angle extension. The diameter of the cerebellopontine angle portion of these tumors ranged from 0.7 to 1.1 cm (mean, 0.9 cm). Total tumor size (including the intracanalicular portion) ranged from 1.0 to 1.8 cm (mean, 1.4 cm).

Results: There were no major complications. One patient developed postoperative cerebrospinal fluid rhinorrhea, which was successfully treated with lumbar drainage, and 12 patients had gross total tumor resection. All of these patients had normal facial nerve function postoperatively. Two of these patients (17%) developed significant delayed facial weakness (House-Brackmann grade 4–5), but, at last follow-up, all patients had maintained or returned to normal facial nerve function. Serviceable hearing (>70% speech discrimination) was preserved in 9/12 patients (75%), and hearing was preserved at the preoperative level (Gardner-Robertson class) in 8/12 (67%). One patient was found to have a tumor originating from the facial nerve. No resection was carried out in this case, and this patient's speech discrimination score improved from 72% to 100%.

Conclusions: Resection of acoustic neuromas via the middle fossa route is often technically challenging. Nevertheless, in appropriately selected cases and using appropriate tools, excellent outcomes can be obtained. The Myriad reciprocating suction microdébrider facilitates debulking in tumors approaching the size limit for this approach. In fact, this device may allow the size limit to be increased. The Myriad proved very useful in all cases in which resection was undertaken (12/13; 92%).