Factors Affecting the Reaccumulation of Chronic Subdural Hematoma after Burr-hole Trephination and Closed-system Drainage

OBJECTIVE: The reaccumulation of hematoma is one of the most frequent problems on the chronic subdural hematoma. The aim of this study is to determine the factors affecting the reaccumulation of hematoma and the reasonable site for the burr-hole trephination to achieve a low reaccumulation rate after burr-hole trephination and closed-system drainage METHODS: The authors studied 93 patients with chronic subdural hematoma in whom the location of burr-hole trephination was randomly placed and precisely determined on postoperative brain computerized tomographic scans or skull roentgenogram. Eighty five patients with chronic subdural hematoma were obtained with brain computerized tomographic scans the postoperative 3 day. The location of the burr-hole trephination, the location of subdural catheter tip, the maximum postoperative width of the subdural space, and the percentage of the ipsilateral subdural space occupied by air postoperatively were measured and analyzed the correlation with the postoperative reaccumulation rates. RESULTS: Patients with the parietal trephination had much more subdural air and a higher of chronic subdural hematoma reaccumulation than those with the frontal one. In addition, patients with residual subdural air on brain computerized tomographic scans obtained the postoperative 3 day also had a higher reaccumulation rate than those without subdural air collections. CONCLUSION: The incidence of postoperative subdural fluid reaccumulation can be reduced by the burr-hole trephination on the frontal convexity and by preventing subdural air accumulation during operation.

A Case of Infected Subdural Hematoma

A 69-year-old man, suffering from diabetes, presented with drowsiness and general weakness is reported. Brain computed tomography revealed low density subdural lesion in the left hemisphere. A single burr hole was trephined and purulent material with liquified hematoma was drained to reveal Klebsiella pneumoniae from the specimen culture. Due to the unexplained postoperative mental deterioration and high fever, the patient underwent abdominal sonography to reveal liver abscess and the same pathogen was also cultured from the liver abscess. This case was very rare in that Klebsiella pneumoniae implanted into the vascularized capsule of the chronic subdural hematoma by hematogenous bacteremia. When chronic subdural hematoma is present in an immunocompromised or in old age patient, the infected subdural hematoma might be considered as one of the differential diagnosis.