The Risk Factors of Symptomatic Communicating Hydrocephalus After Stereotactic Radiosurgery for Unilateral Vestibular Schwannoma: The Implication of Brain Atrophy

Purpose: To identify the effect of brain atrophy on the development of symptomatic communicating hydrocephalus (SCHCP) after stereotactic radiosurgery (SRS) for sporadic unilateral vestibular schwannomas (VS). Methods and Materials: A total of 444 patients with VS were treated with SRS as a primary treatment. One hundred eighty-one patients (40.8%) were male, and the mean age of the patients was 53 ± 13 years (range, 11–81 years). The mean follow-up duration was 56.8 ± 35.8 months (range, 12–160 months). The mean tumor volume was 2.78 ± 3.33 cm3 (range, 0.03–23.30 cm3). The cross-sectional area of the lateral ventricles (CALV), defined as the combined area of the lateral ventricles at the level of the mammillary body, was measured on coronal T1-weighted magnetic resonance images as an indicator of brain atrophy. Results: At distant follow-up, a total of 25 (5.6%) patients had SCHCP. The median time to symptom development was 7 months (range, 1–48 months). The mean CALV was 334.0 ± 194.0 mm2 (range, 44.70–1170 mm2). The intraclass correlation coefficient was 0.988 (95% confidence interval [CI], 0.976–0.994; p < 0.001). In multivariate analysis, the CALV had a significant relationship with the development of SCHCP (p < 0.001; odds ration [OR] = 1.005; 95% CI, 1.002–1.007). Tumor volume and female sex also had a significant association (p < 0.001; OR = 1.246; 95% CI, 1.103–1.409; p < 0.009; OR = 7.256; 95% CI, 1.656–31.797, respectively). However, age failed to show any relationship with the development of SCHCP (p = 0.364). Conclusion: Brain atrophy may be related to de novo SCHCP after SRS, especially in female patients with a large VS. Follow-up surveillance should be individualized, considering the risk factors involved for each patient, for prompt diagnosis of SCHCP. [ABSTRACT FROM AUTHOR]