Could a traumatic epidural hematoma on early computed tomography tell us about its future development? A multi-center retrospective study in China.

Our aim for this study was to quantitatively develop an early epidural hematoma (EDH) natural evolutionary curve and assess association of the most common radiological signs of initially nonsurgical supratentorial EDHs on early computed tomography (CT), in addition to their CT time for EDH enlargement. We retrospectively reviewed pertinent data of supratentorial EDH cases with CT ≤ 6 h postinjury (1997-2013) in three medical institutions in Shanghai. Cases involved were divided into six groups according to their initial CT time postinjury (≤ 1, 1-2, 2-3, 3-4, 4-5, and 5-6 h for groups 1 through 6, respectively). Time of initial CT, EDH-associated fractures, EDH volume, and EDH locations were the focus in the present study. A total of 797 eligible cases were included. The EDH growth curve showed that EDH reached 98.1% of its final stabilized size by volume in 5 ∼ 6 h postinjury. EDH volume and locations on initial CT was greatly associated with subsequent EDH increase ≥ 30 mL with EDH increase requiring surgery when CT time was added. Multi-variate analysis succeeded in determining two risk factors for EDH enlargement ≥ 30 mL and EDH enlargement requiring an operation for EDH cases with an early CT/EDH volume >10 mL on CT performed ≤ 2 h and EDH located at the temporal or temporoparietal region on CT ≤ 1 h post brain injury. Using recursive partitioning analysis, "high-risk" identification criteria were derived to predict EDH enlargement ≥ 30 mL with sensitivity of 90.5% (95% confidence interval [CI], 77.9-96.2), specificity of 60.1% (95% CI, 54.3-65.7), and EDH enlargement requiring surgery with sensitivity of 100.0% (95% CI, 89.9-100.0), and specificity of 59.9% (95% CI, 54.1-65.4). A redo-CT 5 ∼ 6 h post impact for cases at high risk is recommended.