Two hundred ninety-one patients with bCSDH were identified, and 264 of them underwent unilateral (136 patients) or bilateral (128 patients) surgery. The overall retreatment rate was 21.6% (57 of 264 patients). Cases treated with unilateral surgery had twice the risk of retreatment compared with cases undergoing bilateral surgery (28.7% vs 14.1%, respectively, p = 0.002). In accordance with previous studies, the data also showed that a separated hematoma density and the absence of postoperative drainage were independent predictors of retreatment.

In bCSDHs bilateral surgical intervention significantly lowers the risk of retreatment compared with unilateral intervention and should be considered when choosing a surgical procedure ¹⁾.

Ninety-three patients with bilateral CSDH who underwent unilateral bur hole surgery at Aizu Chuo Hospital were included in a retrospective analysis. Findings on preoperative MRI, preoperative thickness of the drained hematoma, and the influence of antiplatelet or anticoagulant drugs were considered and evaluated in univariate and multivariate analyses.

The overall growth rate was 19% (18 of 93 hematomas), and a significantly greater percentage of the hematomas that were iso- or hypointense on preoperative T1-weighted imaging showed growth compared with other hematomas (35.4% vs 2.3%, p < 0.001). Multivariate logistic regression analysis showed that findings on preoperative T1-weighted MRI were the sole significant predictor of hematoma growth, and other factors such as antiplatelet or anticoagulant drug use, patient age, patient sex, thickness of the treated hematoma, and T2-weighted MRI findings were not significantly related to hematoma growth. The adjusted odds ratio for hematoma growth in the T1 isointense/hypointense group relative to the T1 hyperintense group was 25.12 (95% CI 3.89-51.58, p < 0.01).

The findings of preoperative MRI, namely T1-weighted sequences, may be useful in predicting the growth of hematomas that did not undergo bur hole surgery in patients with bilateral CSDH ²⁾.

Huang et al., identified 25 of 98 CSDH (25.51%). The patients with bilateral lesions had a lower incidence of hemiparesis than those having unilateral lesions (p = 0.004). Analysis of the neuro-images revealed significant differences in the presence of a midline shift (p = 0.001) and thickness of the hematoma (p < 0.001).

The mean Markwalder grading score at admission was 1.89 ± 0.66 and 1.64 ± 0.49 in the unilateral and bilateral hematoma groups, respectively (p = 0.010). After a minimum follow-up period of 6 months, the mean Glasgow Outcome Scale was not significantly different (p = 0.060). The recurrence rate of up to 28.00% observed for the bilateral disease was found to be higher than 9.59% observed for the unilateral disease (p = 0.042) ³⁾.