LAUSR

OBJECTIVE The relationship between quantitative posturography results and growth of vestibular schwannoma during conservative management has not been studied. We aimed to clarify the relationship between the presence of disequilibrium based on posturographic measurement and tumor growth. METHODS This retrospective, single-center study included 53 patients with vestibular schwannoma (Koos stage 1 or 2) managed conservatively after initial diagnosis. Radiographic progression was considered present if 20% volumetric growth was observed over the imaging interval. Posturography was performed at initial diagnosis, and sway velocity (SV) and area were calculated. Tumor growth-free survival was estimated using the Kaplan-Meier method. RESULTS The mean follow-up period was 2.87 ± 2.58 years, up to tumor growth detection or the last follow-up MRI. Tumor growth incidence was 40.8% and 61.2% at 2 and 5 years, respectively. Cerebellopontine angle (CPA) extension and sway velocity with eyes open were related to tumor growth. Tumor growth-free survival of those with CPA extension and intracanalicular tumor at 2 years were 37.3% and 76.4%, respectively. Tumor growth-free survival of patients with SV > 2.06 cm/s and ≤ 2.06 cm/s at 2 years was 30.8% and 68.9%, respectively. The Cox hazard model demonstrated a significant risk for future tumor growth at SV > 2.06 cm/s (relative risk 2.475, 95% CI 1.11-5.37, p = 0.027). CONCLUSIONS We demonstrated a positive correlation between sway velocity with eyes open and future tumor growth. Posturographic data are objective and quantitative; thus, SV may be a potential predictor of future growth of vestibular schwannoma.