Management of Facial Nerve Schwannoma: A Multicenter Study of 50 Cases

Background Facial nerve schwannoma (FNS) is a rare entity that poses a difficult treatment paradigm in skull base surgery. In the management of FNS, surgical tumor resection is now often being replaced with more conservative approaches, such as observation with serial imaging or stereotactic radiosurgery (SRS). Given the scarcity of these lesions, determining the optimal management of FNS remains challenging and subject of debate with multiple treatment approaches supported in the literature.

Methods A retrospective chart review was performed, in two academic centers, for patients diagnosed with FNS between 1996 and 2016. The clinical presentation, treatment modalities employed, tumor control rates, and facial nerve function outcomes (House–Brackmann [HB]’s system) were assessed and analyzed.

Results The study comprised 50 adult patients with an average age of 45.8 years at the time of diagnosis. The average follow-up period was 5.7 years (range: 1–9.4 years). Initial treatment modalities included observation with serial clinicoradiologic review in 27 patients (54%), surgery in 17 patients (34%), and SRS in 6 patients (12%). Eight patients (8/27) initially managed with observation needed subsequential treatment; 5 requiring surgery and 3 requiring SRS. One of the patients (one out of six) who had initial SRS required further treatment with surgical resection. Twenty-five surgical procedures were performed in total of which 8 were initially failed from observation (n = 5), SRS (n = 1), and surgery (n = 2). Total resection with nerve grafting, partial resection, or decompression was performed as surgical procedures. The reasons for subsequential treatment were increase in tumor size and progression of associated symptoms. The facial nerve functions were decreased in more than half of the patients who had surgery. Seventy-five percent of these patients had a preoperative HB 1 or 2 nerve function. None of the patients (more than 80%) who were initially managed with observation or SRS had stable or improved facial nerve functions.

Conclusion A prevailing trend toward more conservative treatment modalities for FNS has evolved over time, providing relatively long-term preservation of facial function and limiting exposure to the respective potential morbidity associated with the therapeutic options. As there are multiple management options available, it is of paramount importance that the treating physician be familiar with all treatment modalities and outcomes and counsel patients appropriately regarding the full range of options so that they may play an active role in guiding treatment. The surgery should be reserved for large tumors and poor facial nerve function at initial presentation or follow-up while watchful observation with imaging is the treatment of choice for rest of the patients.