Operationsstrategien für die Entlastung chronischer Subduralhämatome und postoperativer Pneumocephalus

Evacuation of chronic subdural hematoma is a common procedure in neurosurgery and frequently leads to pneumocephalus postoperatively. Several surgical methods such as twist drill craniostomy (TDC), burr hole evacuation (BHE) with or without drainage and craniotomy can be performed with different characteristics concerning for example operation time and anesthesia. The aim of this study was to analyze the incidence of pneumocephalus after surgical evacuation of chronic subdural hematoma, to identify its predictors and its impact on outcome and recurrence. Moreover, we aimed to compare different types of surgery.

Data of 165 patients (mean age 76 yrs [27-96 yrs], 53 females) with first diagnosed chronic subdural hematoma were analyzed retrospectively. Pneumocephalus was defined as space-demanding amounts of air in the subdural space on early postoperative CT scans (maximum 7 days). Multiple linear regression analysis was performed to identify relevant patient and surgery related factors predicting postoperative pneumocephalus. Chi-square tests were used to analyze the relation of pneumocephalus with postoperative neurological deterioration, recurrence rate, functional outcome and surgery type (TDC vs. other methods including BHE with or without drainage and craniotomy). Rates of insufficient surgeries (requirement of second surgery) were compared between surgery types.

69 patients (42%) developed pneumocephalus postoperatively (43% within the group of patients treated with TDC, 41% with other surgery types, n.s.). Patients treated with TDC needed second surgery significantly more often than with other methods (p<0.001). Regression analysis revealed larger initial hematoma volume and less volume reduction as predictors of pneumocephalus (p<0.001 and p=0.024). Pneumocephalus was associated with higher risk of recurrence (p=0.004). Neurological deterioration after surgery and functional outcome were not associated with pneumocephalus.

Pneumocephalus is a common complication after evacuation of chronic subdural hematoma, especially in case of larger hematomas. It seems to be associated with higher recurrence rates, which may require more surgeries and further hospital stays with a negative impact on patients' quality of life and costs. Treatment with TDC seems to be less efficient than other surgical methods and should not be the first choice.