Author(s)
Bora Agabigum, MD, MS
Tyler J. Gathman, MD, MS
Hyunseo Jung, MD
Jeffrey Turnbull, DO
Alex Lampi, BS
Rafi Hanna, BS
Dennis Bojrab II, MD
Affiliation(s)
Michigan Ear Institute
Abstract:
Objective: Stereotactic radiosurgery has proven highly effective in managing small to medium-sized skull base tumors, offering adequate tumor control as a non-invasive modality that minimizes surgical risk. Despite these advantages, long-term studies on clinical and tumor burden outcomes have been limited.
Study Design: Retrospective cohort study.
Setting: Tertiary care academic.
Patients: This study analyzed 135 patients with cerebellopontine angle tumors who received primary stereotactic radiosurgery between 2010 and 2025. The mean patient age was 63.8 years (range 41–90), and 55.5% (n = 60) were male. All patients underwent Gamma Knife treatment. Vestibular schwannoma was the most common diagnosis (94.8%; n = 128), followed by meningioma (4.4%; n = 5) and glomus tumor (0.7%; n = 1). The mean follow-up duration after primary treatment was 5.7 years.
Interventions: Stereotactic radiosurgery with Gamma Knife for primary cerebellopontine angle tumor treatment.
Main Outcome Measures: Tumor control was evaluated by magnetic resonance imaging at less than 1 year and more than 2 years after treatment. The rates of refractory tumor growth and subsequent surgical resection were also determined.
Results: Prior to radiosurgery, the mean maximal tumor dimension measured 13.2 mm. After more than 2 years, 15.5% (n = 16) exhibited persistent tumor growth or treatment failure, while 9.6% (n = 13) ultimately underwent surgical resection. Audiometric testing revealed a mean pre-radiosurgery pure tone average of 38.8 dB, with 21.4% (n = 29) of patients experiencing greater than 20 dB increase after radiosurgery.
Pre-radiosurgery, 2.8% (n = 3) of patients had facial nerve deficits defined as House-Brackman > 1, and no patients developed deficits from initial normal function following radiosurgery. Vestibular testing demonstrated 66.6% (n = 70) of patients had ipsilateral vestibular dysfunction after radiosurgery.
Conclusions: Radiosurgery offers effective tumor control with limited need for surgical resection. However, there are demonstrated risks to hearing preservation and vestibular function that require long-term monitoring.
Learning Objective: Radiosurgery continues to be an effective option for treatment cerebellopontine angle tumors and in avoiding surgical resection; however, patients require ongoing monitoring of both audiogram and vestibular function.
Desired Result: Patients undergoing radiosurgery may retain both hearing and vestibular function; however, any deficits should be promptly identified and managed.
Level of Evidence - Level III, Retrospective Cohort Study
Indicate IRB or IACUC: The study was reviewed and IRB-approved by Henry Ford Health.