Introduction: A significant number of patients who undergo surgical evacuation of chronic subdural hematoma (cSDH) return to the operating room for re-evacuation (RTOR). The purpose of this study was to examine clinical and radiographic characteristics that may contribute to RTOR.

Methods: A retrospective review of 244 consecutive patients undergoing surgical evacuation of cSDH from January, 2010 through December, 2011 was performed. Pre-operative risk factors, radiographic characteristics and surgical reports were analyzed. The interaction between variables was analyzed via Chi-Square and binary logistic regression using IBM SPSS version 20.

Results: There were 302 cSDH and 342 operations performed. 35 (13%) returned to the operating room. The type of surgery performed was a significant predictor of RTOR. Compared to a burr hole, a small craniotomy had 1.97 greater odds (p=0.062) and a craniotomy > 3 cm had 2.54 greater odds (p=.007) of RTOR. This finding remained significant when controlling for CT characteristics, including the presence of significant loculations. 12 (3.6%) of the 330 operations resulted in acute SDH (aSDH). The CT characteristics significantly (p=0.03) correlated with RTOR for aSDH, as well as the type of surgery done. Loculated cSDH drove this association representing 8/12 or 67%. All 12 RTOR for aSDH occurred after craniotomy > 3cm (p=0.00). There was no significant difference in the use of anticoagulant or anti-platelet drugs, age, or presence of diabetes between patients who had one or multiple operations.

Conclusions: In the management of cSDH, a craniotomy > 3cm confers no benefit over a burr hole or small craniotomy with respect to RTOR. This holds true for loculated cSDH. In addition, patients with loculated cSDH appear to be at a higher risk of aSDH when treated with a craniotomy > 3cm.

Patient Care: This research will improve patient care by 1)avoiding unnecessary craniotomies in patients who are unlikely to benefit; 2) decreasing the incidence of acute subdural hematomas after evacuation of chronic subdural hematomas; 3) decreasing RTOR for patients with chronic subdural hematomas.

Learning Objectives: By the end of this session, participants should be able to 1) describe the risks associated with different surgical techniques used to manage chronic subdural hematomas; 2) discuss, in small groups, the importance of CT characteristics in choosing a surgical technique; 3)determine when a burr hole should be the surgery of choice for management of chronic subdural hematomas.

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