Predictors of functional outcomes and recurrence of chronic subdural hematomas.

We aimed to evaluate the functional outcome and risk factors of recurrence in patients operated on for a chronic subdural hematoma (CSH), and discuss systematic early postoperative CT scans. CSH is a very common disease in neurosurgical practice, especially in elderly patients who are treated with anticoagulation. The challenge is to rapidly restore the independence of these patients. We retrospectively analyzed data from 164 consecutive surgical procedures performed on 140 CSH patients, including recurrent surgery, at our institution from June 2011 to June 2012. Pre- and postoperative CT scans, and medical records, were systematically reviewed using the institutional computing database. A poor functional outcome was defined by a modified Rankin scale (mRS) score>2 at 3 months. Among the 140 patients (mean age 76 years; 64% men), a single burr hole craniostomy was performed in 122 patients, and a craniotomy in 18. A poor functional outcome was recorded in 39 patients (28%; 95% confidence interval [CI] 20-35%). In multivariate analyses, an increased risk of poor functional outcome was associated with age >75 years (odds ratio [OR] 5.88; 95% CI 1.96-17.63), residual hematoma thickness >14 mm (OR 3.79; 95% CI 1.47-9.77), and GCS<15 (OR, 2.96; 95% CI, 1.18-7.40). Recurrences occurred in 24 patients (17%; 95% CI 11-23%), with a median delay to reintervention of 13 days. The independent predictors of CSH recurrence were preoperative anticoagulant therapy (OR 3.68; 95% CI 1.13-12.00), and persistence of mass effect on the postoperative CT scan (OR 5.61; 95% CI 1.52-20.66). Three months after surgical treatment, more than one quarter of the CSH patients had a mRS⩾3. The loss of independence was associated with older age, initial GCS<15, and residual hematoma thickness postoperatively. Anticoagulant therapy and persistence of postoperative mass effect heightened the risk of recurrence.