Risk factors for development of significant chronic subdural hematoma following conservative treatment of acute subdural hemorrhage.

Objective: One of the complications of untreated acute subdural hemorrhage (aSDH) is the late development of chronic subdural hematomas (cSDH). cSDH may cause major neurologic deficits, requiring their surgical evacuation. The aim of our work was to find risk factors for the development of significant cSDH requiring surgery following conservative treatment of trauma-related aSDH.

Methods: In a retrospective manner, we analyzed the data of 95 adult patients admitted with a non-surgical, traumatic aSDH. The patients were divided into two groups. The first group contained 52 patients who did not, on follow-up, develop cSDH requiring surgery. The second group contained 43 patients who ended up with a significant cSDH, based on clinical and radiological criteria, requiring surgical evacuation. Data acquisition and comparison between the two groups was performed by analyzing the patients' charts for diverse medical conditions and other trauma-related parameters.

Results: The operation rate was significantly higher in patients with medical history of ischemic heart disease (IHD) or hypertension (66.7% vs. 38%, p = 0.019 and 56.9% vs. 20%, p < 0.01, respectively), with a 4-fold increase in the risk for developing surgical cSDH in patients with IHD and a 6-fold increase in the risk in patients with hypertension (odds ratio 4.2 [95% CI for odds, 1.3-13.1] and 5.9 [95% C.I for odds, 1.6-21.5], respectively). Among 21 patients, 20 (95%) patients, who were either on more than 1 anti-aggregant agents (AAA), used Clopidrogrel, or took anti-coagulant drug were in the operative group (OG). A larger initial thickness of the aSDH was statistically significant in the OG as compared to the non-OG (8.9 mm ± 4.6 vs. 5.5 mm ± 2.1, p < 0.001).

Conclusion: Head-trauma patients with a medical history of IHD or hypertension, patients on more than one AAA or anti-coagulant agents and patients with worse initial CT scan parameters are at risk of developing significant cSDH requiring surgery after conservative treatment of aSDH and consequently should have closer follow-up.