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 sub dural drainage catheter to achieve a low recurrence rate after burr-hole ir rigation and closed-system drainage of chronic subdural hematoma (CSDH). Methods. The authors studied 63 patients with CSDH in whom the drainage cat heter tip was randomly placed and precisely determined on postoperative com puterized tomography (CT) scans and 104 patients with CSDH in whom CT scans were obtained 7 days postsurgery. The location of the subdural drainage ca theter, the maximum postoperative width of the subdural space, and the perc entage of the ipsilateral subdural space occupied by air post operatively w ere determined and compared with the postoperative recurrence and reoperati on rates. Patients with parietal or occipital drainage had a higher rate of CSDH recu rrence and much more subdural air than those with frontal drainage. In addi tion, patients with residual subdural air demonstrated on CT scans obtained 7 days postsurgery also had a higher recurrence rate than those without su bdural air collections. Furthermore, patients with a subdural space wider t han 10 mm on CT scans obtained 7 days postsurgery had a higher recurrence r ate than those with a space measuring 10 mm or less. Conclusions. The incidence of postoperative fluid reaccumulation seems to b e reduced by placing the tip of the drainage catheter in the frontal convex ity and by removing subdural air during or after surgery.