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.