Eur J Trauma Emerg Surg. 2026 Jul 23;52(1):228. doi: 10.1007/s00068-026-03275-5.
ABSTRACT
PURPOSE: The clinical impact of acute-on-chronic subdural hematoma (acSDH) in mild traumatic brain injury (mTBI) remains incompletely characterized. We assessed whether acSDH, compared with isolated acute SDH (aSDH), is associated with worse neurological presentation and increased radiological markers of mass effect.
METHODS: We conducted a retrospective multicenter cohort study using the IMADIS teleradiology head trauma workflow (103 emergency departments in France, January 2020 to December 2022). Adult patients with complicated mTBI (i.e., GCS 13-15 plus intracranial hemorrhage or skull fracture) and acute SDH on non-contrast head CT were eligible. Exposure was acSDH versus aSDH based on structured radiology reports. Outcomes were (1) GCS < 15 at presentation, (2) SDH maximal thickness ≥ 7 mm, (3) radiological brain herniation, and (4) intermediate or high QueBIC risk category. Univariable and multivariable logistic regression models were used to estimate associations.
RESULTS: Among 935 included patients, 107 (11.4%) had acSDH. Patients with acSDH were older (≥ 75 years: 57.0% vs. 39.7%, p < .0001) and more frequently had dementia (8.4% vs. 3.7%, p = .0465). Compared with aSDH, acSDH was associated with GCS < 15 (37.4% vs. 21.7%, P = .0010) and confusion (41.0% vs. 25.8%, p = .0016). On CT, acSDH was associated with SDH thickness ≥ 7 mm (54.2% vs. 20.4%, OR 4.50, 95%CI 2.90 to 7.01) and brain herniation (27.1% vs. 10.7%, OR 3.61, 95%CI 2.20 to 5.85). AcSDH was independently associated with intermediate or high QueBIC category (OR 3.38, 95%CI 1.95 to 6.27) and with the other severity markers.
CONCLUSION: In complicated mTBI with acute SDH, acSDH is associated with worse neurological presentation and substantially higher radiological markers of mass effect, as well as a higher QueBIC risk category. These findings support considering acSDH as a high-risk imaging phenotype that may warrant closer early monitoring and timely neurosurgical discussion. Future studies should evaluate associations with patient-centered clinical outcomes and neurosurgical interventions. This retrospective, observational, multicenter study was approved by the French National Radiological Review Board (CRM-2507-489, on 16 July 2025).
PMID:42489732 | DOI:10.1007/s00068-026-03275-5