Surgical treatments for chronic subdural hematomas: a comprehensive systematic review.

BACKGROUND: Chronic subdural hematomas (CSDHs) are common neurosurgical conditions among elderly patients. OBJECTIVE: To perform a detailed critical appraisal of all randomized controlled trials (RCTs) of surgical treatments for chronic subdural hematomas and to quantify their intervention effects. - METHODS: We performed a broad search for all RCTs with no language or date restrictions, asked the authors for missing data, and applied the Cochrane methods. RESULTS: A total of 24 RCTs involved 1900 patients and 15 comparisons. All outcomes of practical interest were analyzed. Postoperative drainage after burrhole evacuation reduced the rate of recurrence (risk ratio 0.48, 95% confidence interval 0.34-0.66, P < 0.00001) with no other clear benefits or complications. CONCLUSIONS: This comprehensive, best evidence-based, quantitative, systematic review indicates that the use of a closed system drainage after burrhole evacuation reduces the rate of recurrences but has no other significant differences. The findings also suggest that: (1) treatment with twist drills is equivalent to that with burr holes; (2) the postoperative bed header in the elevated position might reduce the length of hospital stay; (3) irrigation of the subdural space with thrombin solution in patients with high risk of recurrence might reduce this risk; and (4) treatment with twist drill followed by a closed system drainage during 48 hours, instead of 96 hours, might reduce general complication rates. Most of the trials suffered from unclear or high risks of bias and many involved small samples, precluding strong and definitive conclusions.