Risk Factors for Recurrence of Chronic Subdural Hematoma: A Single Center Experience

OBJECTIVE: Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a substantial recurrence rate. We aimed to investigate the predictive factors for the postsurgical recurrence of CSDH. METHODS: We retrospectively reviewed the medical records of patients with CSDH who underwent surgery in West China Hospital between January 2012 and June 2018. Univariate and multivariate analyses were performed to identify the relationships between recurrence of CSDH and factors such as age, sex, history of injury, Markwalder grading, computed tomography findings, surgical methods, and outcomes. RESULTS: A total of 328 patients (281 men and 47 women) aged 22-93 years (mean age, 65.14 +/- 13.76 years) were included. Computed tomography findings at admission showed mixed density hematoma in 136 patients, isodensity hematoma in 140, high-density hematoma in 34, and low-density hematoma in 18. The mortality and recurrence rate were 0.30% (1 of 328) and 2.44% (8 of 328), respectively. Six months postoperatively, 327 patients had Markwalder grade 0. Hematoma recurred in 8 patients of which 7 were mixed density hematoma and 1 was isodensity hematoma. Six patients who underwent craniotomy had thickened inner neomembrane that was resected. Univariate and multivariate analyses found mixed density hematoma to be an independent risk factor for the recurrence of CSDH. CONCLUSIONS: Burr hole craniostomy with irrigation and closed-system drainage is effective for the surgical treatment of CSDH. Mixed density hematoma is an independent predictor for the recurrence of CSDH. Presence of thick inner neomembrane might be the primary cause of CSDH recurrence.