Abstract
Organized hematoma, which exhibits a net-like appearance on imaging studies, is one of the predisposing factors for the recurrence of chronic subdural hematoma. Patients who are positive for the net-like appearance are often treated with only burr hole surgery. We investigated the relationship between postoperative structural changes in the net-like appearance and the recurrence rate of chronic subdural hematoma. Of the 949 patients with chronic subdural hematoma treated with primary burr hole surgery between January 2010 and April 2021 at our hospital, 268 who were considered positive for the net-like appearance on T2- and T2 star-weighted magnetic resonance images were extracted. We followed the structural changes in the net-like appearance postoperatively and subsequently classified the patients into three groups: decreasing type, shifting type, and no change and deterioration type. The relationship between each structural change and the recurrence rate in the three groups was investigated. Postoperative recurrence requiring surgery occurred in 3.5% of the subjects with decreasing type, 0% with shifting type, and 100% with deterioration type of the net-like appearance (P < 0.05), indicating differences in the recurrence rates according to postoperative structural changes in the magnetic resonance images (MRI) features of chronic subdural hematoma. Our results indicate that the risk of postoperative chronic subdural hematoma recurrence can be predicted by focusing on the structural changes in the postoperative net-like appearance on MRI.