Gradation density hematoma is a predictor of chronic subdural hematoma recurrence associated with inflammation of the outer membrane

Abstract

ObjectivesChronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a high recurrence rate. This study aimed to determine the CSDH recurrence rate associated with preoperative computed tomography (CT) findings and the pathological examination of the dura and the outer membrane. Patients and MethodsWe retrospectively reviewed the medical records of patients with CSDH who underwent surgery in our hospital between May 2010 and November 2019. CSDHs were classified into four groups according to the hematoma density on CT: low-density hematoma (LDH), gradation-density hematoma (GDH), iso-density-hematoma (IDH), and mixed-density hematoma (MDH). The postoperative recurrence rate was calculated for each group, and we examined whether the recurrence rate correlated with the CT findings. We also took samples of the dura to analyze inflammatory cell infiltration and the blood vessels. ResultsA total of 388 patients were analyzed. The total recurrence rate was 13.7%. CT findings at admission showed LDH in 50, GDH in 136, IDH in 110, and MDH in 92 patients. The recurrence rate of GDH (23.5%, 32/136) was comparable to the rate of the other CSDH types (11.5%, 61/388). Univariate and multivariate analyses found GDH to be an independent risk factor for the recurrence of CSDH. GDH patients displayed much more angiogenesis and inflammatory cell infiltration in the outer membrane and the dura. ConclusionGDH is an independent predictor for CSDH recurrence. The presence of inflammation in GDH might be the primary cause of CSDH recurrence.