Treating Vestibular Schwannomas with Gamma-Knife Radiosurgery Versus Microsurgery: Long-Term Follow-up of 702 Cases

Abstract
Background: The three treatment options currently con-sidered for vestibular schwannoma are expectant treatment, microsurgery and radiosurgey, and to date no class I evidence favors one treatment over the others.
Aim of Study: The objective of this study was to compare long-term functional outcome after gamma knife radiosurgery versus surgical treatment.
Methods: A group of 275 patients submitted to microsur-gery and 427 patients treated with radiosurgery in two different centers were followed-up for 15.2±13.6 months and 45.6±26.8 months, respectively. We assessed tumor volumetry based on serial MR images, facial nerve function, hearing function, tinnitus, trigeminal symptoms and vertigo, and compared them between treatment groups.
Results: Based on normalized volumetry over time, surgery was more efficient for tumor control than radiosurgery (p<0.001). After radiosurgery, hearing and facial nerve func-tions remained stable regardless of tumor size. On the other hand, after surgery, there was clinical deterioration for both small and large tumors, yet the deterioration for small tumors was very discrete, rendering quite similar functional results across groups in this category. Furthermore, surgery alleviated symptoms like facial hypoesthesia, dizziness, and tinnitus more effectively than radiosurgery.
Conclusion: These results represent an important contri-bution to the field and offer evidence-based criteria to support the indication of a particular treatment modality according to the patient's expectations and professional activity.