Surgical Outcome in Smaller Symptomatic Vestibular Schwannomas: Is There a Place for Surgery as First Option?

Background: Small or medium size vestibular schwannomas are routinely watched and/or referred for radiosurgical treatment. The natural history of smaller tumors are marked by gradual decrease in hearing, possibility of developing vestibular symptoms and possible tumor growth. We hereby evaluate the clinical outcomes of patients undergoing surgical removal of their symptomatic small vestibular schwannomas.

Methods: During a period of 7 years (2009–2016), patients with small vestibular schwannomas(grade I to grade IIIb according to Hanover classification) were reviewed. Patients with symptomatic tumors who were assigned for surgery were evaluated. Their preoperative hearing status was based on the guideline of the committee on hearing and equilibrium of the American Academy of Otolaryngology- Head and Neck Surgery foundation. Their post-operative facial nerve function, hearing status, vestibular symptoms, and degree of tumor resection were assessed. Surgical outcome for other parameters and complications were also evaluated.

Results: Thirty patients were selected for surgery via a retrosigmoid craniotomy based on their age(all less than 70 year old), symptoms and their own decision making after discussion of management options. Twenty-two patients presented with some degree of hearing loss, twelve had vestibular symptoms(vertigo and/or tinnitus) and five patients presented with documented tumor growth before the surgery. No patients with incidental finding was offered surgery. Twenty seven patients(90%) had grade I-II House-Brackman facial nerve function post-operatively. Two(7%) had grade III and one(3%) had grade IV HB. At 3 months follow-up, 29 patients(97%) had HB grade I-II. Seventeen patients had still a serviceable hearing(10 patients in Grade A and 7 in Grade B) pre-operatively. Grade C hearing was not considered as useful. Among those, 10 patients preserved useful hearing after surgery(70% of patients with Grade A hearing and 43% with Grade B hearing pre-operatively). Pre-operative vertigo/tinnitus improved in 5(42%). Preserved facial motor stimulation and ABR at the completion of surgery were associated with post-operative preserved function of facial and cochlear nerve respectively. Immediate post-operative MRI confirmed unequivocal complete tumor resection in twenty six(87%). Four had tiny(2mm) intracanalicular enhancement despite apparent complete removal at surgery. At a median follow-up of 43+_12 months(range 5–86 months), the long-term MRI confirmed complete resection in 29(97%). Except for one patient with CSF leak, one patient with delayed facial nerve palsy and one with asymptomatic sigmoid sinus occlusion, there was no other new morbidities.

Conclusion: Although both observation and radiosurgery are valid options in the management of smaller size vestibular schwannomas, surgical treatment seems to offer an excellent rate of facial nerve preservation, a reasonable rate of hearing sparing and an excellent total resection rate. The risk of tumor recurrence is low after surgical treatment of smaller vestibular schwannomas. Clinicians should consider surgical treatment as a valid option and possibly the first choice in the initial management of symptomatic small vestibular schwannomas in younger patients.