To Drain or Two Drains: Recurrences in Chronic Subdural Hematomas.

BACKGROUND Chronic subdural hematoma (cSDH) is a common neurosurgical condition, with an estimated incidence of 3-15.5 per 100,000 people, with significantly higher rates in the elderly population. Recurrence rates range from 2%-37% after surgical drainage. Studies have shown that leaving a drain postoperatively can reduce recurrence rates, but studies have not looked at whether there is a difference between leaving 1 or 2 drains. METHODS We analyzed 215 patients undergoing burr hole drainage for 261 cSDHs in terms of preoperative comorbidities and postoperative drain placement. RESULTS Recurrences requiring repeat evacuation occurred in 6.1% overall, in 6/110 patients (5.5%) with 1 burr hole, and in 11/151 patients (7.3%) who had 2 burr holes, which was not significantly different. Recurrences occurred in 1/15 patients (6.7%) with no drain, 13/210 patients (6.2%) with 1 drain, and in 2/36 patients (5.6%) with 2 drains, which was also not statistically significant. The only medical comorbidity associated with an increased risk of recurrence was liver disease (P = 0.014). CONCLUSIONS This study demonstrates that neither the number of burr holes nor the number of drains left after a burr hole drainage of cSDH appear to affect recurrence rates, whereas liver disease does make recurrence more likely.