Object. The aim of this study was to determine the influence of closed-system subdural drainage on repeated operation rates after burr hole evacuation of subacute and chronic subdural hematomas (SDHs).
Methods. Five hundred consecutive operations for the treatment of SDH via burr holes were performed between January 1, 1996, and April 15, 2002, at the Auckland Hospital. Hospital records were used to ascertain demographic data, operation, and repeated operation details. Rates of repeated surgeries were compared in patients with and without subdural drains.
Repeated operations were performed less frequently in patients with subdural drains, occurring in 31 (10%) of 310 cases involving drains and in 35 (19%) of 188 cases without drains (p < 0.01). Demographics between the two groups were not significantly different except for mean patient age, which was higher among patients with a subdural drain. A lower rate of repeated operation was observed in patients who had undergone drain placement, regardless of whether there was visible evidence of brain reexpansion.
Conclusions. Patients have lower rates of repeated surgeries if subdural drains are placed following evacuation of an SDH via a burr hole. To reach high clinical significance, 12 patients must undergo this simple intervention. If technically feasible, subdural drains should be inserted regardless of any occurrence of brain expansion during surgery.