Risk Factors for Recurrence in Patients Surgically Treated for Chronic Subdural Hematomas: A Single Institutional Experience

Background: Chronic subdural hematoma (CSDH) is a common neurosurgical condition that usually occurs in the elderly. Surgical evacuation of the hematoma with burr holes is considered the standard of care for the treatment of patients with CSDH. However, a high risk of recurrence, up to 34%, after hematoma evacuation has been reported, while the risk factors linked with recurrence have not been studied in depth. In the present study, we set out to identify risk factors of recurrence in patients surgically treated for CSDH. Methods: We retrospectively studied patients with symptomatic CSDH who were treated surgically in our institute during a five-year period. All the patients were treated by single or double burr hole drainage. The data for this study were extracted by the pre-operative and post-operative CT scan of each patient. These data include the sex, the midline shift, the width, and the presence of acute clots and subdural air collection post-operatively. A univariate analysis was performed. A receiver operating characteristic (ROC) analysis was utilized to detect the hematoma’s width more efficiently, differentiating patients that developed recurrence. Results: A total of 222 patients were included in this study. Recurrence occurred in 20 (9.0%) patients. The univariate analysis showed that the presence of acute clots post-operatively are significant factors related with recurrence (OR = 4.01, CI 95% 1.55–10.33, and p = 0.002). There was no significant relationship between the recurrence rate and the hematoma’s width, sex, the midline shifts pre-operatively or post-operatively, the subdural space, and air collection post-operatively. Conclusions: The presence of acute clots in the post-operative CT scan is a potential, previously unexplored, risk factor associated with the recurrence of CSDH.