Relationship between drainage catheter location and postoperative recurrence of chronic subdural hematoma after burr-hole irrigation and closed-system drainage

Object. This study was conducted to determine the best position for the subdural drainage catheter to achieve a low recurrence rate after burr-hole irrigation and closed-system drainage of chronic subdural hematoma (CSDH). Methods. The authors studied 63 patients with CSDH in whom the drainage catheter tip was randomly placed and precisely determined on postoperative computerized tomography (CT) scans and 104 patients with CSDH in whom CT scans were obtained 7 days postsurgery. The location of the subdural drainage catheter, the maximum postoperative width of the subdural space, and the percentage of the ipsilateral subdural space occupied by air postoperatively were determined and compared with the postoperative recurrence and reoperation rates. Patients with parietal or occipital drainage had a higher rate of CSDH recurrence and much more subdural air than those with frontal drainage. In addition, patients with residual subdural air demonstrated on CT scans obtained 7 days postsurgery also had a higher recurrence rate than those without subdural air collections. Furthermore, patients with a subdural space wider than 10 mm on CT scans obtained 7 days postsurgery had a higher recurrence rate than those with a space measuring 10 mm or less. Conclusions. The incidence of postoperative fluid reaccumulation seems to be reduced by placing the tip of the drainage catheter in the frontal convexity and by removing subdural air during or after surgery.