Differences in Presentation, Radiological Features, and Outcomes in Traumatic Versus Spontaneous Acute Subdural Hematomas-A Single-Institution Population-Based Study

BACKGROUND: Spontaneous acute subdural hematoma (sASDH) is a rare neurosurgical condition, with the literature mainly consisting of case reports. In the present study, we compared sASDH with traumatic ASDH (tASDH) to determine the differences in presentation, radiological features, and outcomes in a population-based setting.

METHODS: All adult patients (age ≥18 years) who had undergone surgery for ASDH (n = 266), either spontaneous or traumatic, from 2010 to 2020 were included retrospectively. The cohort was divided into 2 groups for comparative analysis: sASDH group (n = 24) versus tASDH group (n = 242).

RESULTS: Of the 266 patients, 24 (9.0%) had presented with sASDH. The sASDH group had a mean age of 66.2 years, and sudden headache was the most common presenting symptom (83.3%). The sASDH group had a higher Glasgow coma scale score at presentation compared with the tASDH group (Glasgow coma scale scores, 10 and 8, respectively; P < 0.01). The outcomes, assessed using the Glasgow outcome scale (GOS), revealed a greater incidence of more favorable outcomes (GOS score 4-5) for the sASDH group (72.7%) than for the tASDH group (41.5%).

CONCLUSIONS: In the present population-based study of surgically evacuated ASDH cases, 9% were spontaneous without previous trauma. The outcomes (GOS scores) were significantly more favorable for those with sASDH than for those with tASDH. In one half of the patients with sASDH, arterial bleeding was noted perioperatively, although the preoperative radiological examinations revealed no abnormalities for most patients. However, the lack of sufficient examinations such as computed tomography angiography made it difficult to establish the most common etiology of bleeding in those with sASDH. Further research is warranted to determine the reference standard method for the investigation of sASDH.