Factors Contributing to Surgical Intervention for Subacute Subdural Hematoma Enlargement in Patients with Mild Head Injuries

Abstract

Delayed neurological deterioration following mild head injury(MHI)usually occurs within 24 hours. However, some cases require delayed surgical evacuation of an acute subdural hematoma(ASDH), owing to subacute progressive hematoma enlargement. This study aimed to determine radiological or clinical parameters associated with surgical intervention in ASDH cases in which surgery was not initially considered necessary. From 2010 to 2015, 64 patients were non-surgically treated for ASDH following MHI. We evaluated the various outcomes of eventual surgical ASDH evacuation after the first 48 hours following injury, due to hematoma enlargement and clinical deterioration. Univariate and multivariate analyses were applied to both the demographic and initial radiographic features to identify risk factors for ASDH progression and surgery. Overall, at the time of their last follow-up computed tomography, 57 patients(89%)demonstrated minimal ASDH or spontaneous hematoma resolution with conservative non-surgical management. The remaining 7 patients(11%)received delayed surgical ASDH evacuation a median of 5.1 days after the head trauma. There were no significant differences between the two groups for baseline characteristics, including age, prior history of anticoagulants, the presence of cerebral contusions, or subarachnoid hemorrhages. On multivariate analysis, use of antiplatelet drugs(p=0.013, OR=28, 95%CI=1.82-24)was independently associated with delayed hematoma evacuation. These data indicate that as much as 11% of patients with minimal ASDHs after MHI can deteriorate over the course of a week and then require surgical intervention, and that patients on concurrent antiplatelet medication require especially careful monitoring of hematoma progression.