ABSTRACT
OBJECTIVE: Considerable recurrence rates have been reported for chronic subdural hematoma (CSDH) following surgical evacuation. The aim of this study was to determine the independent factors and features of CSDH that are associated with postoperative recurrence. METHODS: Retrospective analysis of 136 consecutive patients diagnosed with CSDH who were surgically treated from September 2005 to December 2011 was performed. The demographic data, clinical characteristics, radiologic features were analyzed to clarify the correlation between independent variables and postoperative recurrence of CSDH. RESULTS: CSDH was resolved within 1 month following surgery in 51 patients (37.5%), between 1 to 3 months in 59 patients (43.4%), and past 3 months in 14 patients (10.3%). A total of 12 patients (8.8%) experienced recurrence of CSDH, and reoperation was performed in all recurred cases. The average duration between initial surgery and reoperation was 20.1 days. Delayed resolution and recurrence were more commonly presented in bilateral CSDH, but this data was not statistically significant. Large hematomas with maximum thickness over 20 mm were significantly correlated with higher recurrence rates of CSDH (p=0.032). In addition, the incidence of recurrence was significantly higher in the cases with high-density and mixed-density hematomas according to brain computed tomography (CT) findings (p=0.0026). CONCLUSION: The thickness and density of the hematoma is significantly correlated with higher recurrence rates of CSDH. Discerning these risk factors could be beneficial in predicting the postoperative recurrence of CSDH.