The Danish Chronic Subdural Hematoma Study—Risk Factors for Second Recurrence

Treatment of multiple recurrent chronic subdural hematomas (CSDH) is challenging. Identification of specific risk factors for multiple recurrences may allow a higher degree of personalized treatment, including closer postoperative follow-up, detailed prognostication, and a more aggressive initial surgical strategy, such as craniotomy, adjuvant embolization of the middle meningeal artery, or adjuvant medical treatment, such as steroids. The aim of this study was to identify pretreatment risk factors for a second recurrence of CSDH (re-re-CSDH) and risk factors for developing re-re-CSDH once operated for the first recurrence.Clinical and demographic data on all Danish patients admitted to a neurosurgical department with CSDH between 2010 and 2012 were retrospectively recorded. Data were retrieved before the evacuation of a primary CSDH, a first recurrent CSDH (re-CSDH), and a re-re-CSDH. We compared patients undergoing first, second, and third CSDH evacuation to identify risk factors for re-CSDH and re-re-CSDH.The cohort comprised 1052 patients, with 172 patients with re-CSDH and 29 patients with re-re-CSDH. Risk factors for re-re-CSDH included radiological subtype, midline shift, and hematoma volume, while postoperative drainage lowered the risk of re-re-CSDH. These risk factors were not specific for re-re-CSDH.We found similar independent risk factors for re-CSDH and re-re-CSDH, and for re-re-CSDH once treated for re-CSDH. Hence, it was not possible to identify specific risk factors for patients at risk of re-re-CSDH at the time of the primary diagnosis.