Adjunctive middle meningeal artery embolization with low-viscosity liquid embolic agents for acute epidural hematoma: technical considerations and a case series.
Shen H, Qian Y, et al. • Frontiers in neurology • 2026
Adjunctive middle meningeal artery embolization with low-viscosity liquid embolic agents (1:1 diluted Onyx/DMSO and 1:9 diluted Glubran 2/ethiodized oil) was technically feasible with a favorable short-term safety profile in selected acute epidural hematoma patients.
Key Findings
Results
Technical success was achieved in all embolized acute epidural hematoma cases using low-viscosity liquid embolic agents.
Eight of 9 consecutive AEDH patients underwent MMA embolization; one was converted to immediate craniotomy due to rapid hematoma expansion on pre-procedural CT.
Technical success rate was 100% (8/8) among embolized patients.
Two different low-viscosity agents were used: 1:1 diluted Onyx with DMSO (n=6) and 1:9 diluted Glubran 2/ethiodized oil (n=2).
The study was a retrospective consecutive case series at a single institution.
Results
Low-viscosity liquid embolic agents reached distal dural branches without relevant proximal reflux or catheter complications.
No catheter adherence or catheter entrapment was observed in any of the 8 embolized cases.
Agents reached distal dural branches without relevant proximal reflux.
No procedure-related complications occurred across the embolized cohort.
The authors note these agents balance 'distal penetration and catheter control.'
Results
Follow-up imaging demonstrated stable or resolving hematomas in all embolized patients, with no cases requiring rescue surgery.
All 8 embolized patients showed stable or resolving hematomas on follow-up imaging.
None of the embolized patients required rescue surgery for post-embolization hematoma expansion.
Median discharge Glasgow Coma Scale (GCS) score was 15.
No new neurologic deficits were observed in any embolized patient.
Results
One patient was converted to craniotomy after pre-procedural CT demonstrated rapid interval hematoma progression before embolization could be performed.
This conversion case represented 1 of 9 total patients reviewed (approximately 11%).
The decision to convert was made based on pre-procedural cranial CT showing rapid hematoma expansion.
Prompt craniotomy was performed in this non-embolized conversion case.
This case illustrates that patient selection and pre-procedural imaging are critical to determining suitability for MMA embolization.
Conclusions
The authors conclude that adjunctive MMA embolization with low-viscosity agents may provide a minimally invasive treatment option for high-risk AEDH but requires larger multicenter studies for confirmation.
The authors state the strategy 'may help control bleeding and reduce the risk of hematoma expansion while balancing distal penetration and catheter control.'
The authors explicitly call for 'multicenter studies with larger retrospective case series' to confirm these findings.
The study was limited to 9 patients at a single institution with short-term follow-up.
The authors frame MMA embolization as an adjunctive, not standalone, treatment strategy for selected AEDH patients.
What This Means
This research describes a small case series of 9 patients with acute epidural hematomas (blood clots between the skull and the outer covering of the brain, often caused by head trauma) who were evaluated for a minimally invasive procedure called middle meningeal artery (MMA) embolization. This procedure involves threading a small catheter into the artery that supplies blood to the area of bleeding and injecting a material to block blood flow, potentially stopping the hematoma from growing. The study specifically tested two specially diluted 'liquid embolic' agents that are thinner than standard formulations, allowing them to penetrate deeper into smaller vessels. Eight of the nine patients underwent successful embolization, while one patient had to be taken to immediate brain surgery because their hematoma was expanding too rapidly before the procedure could begin.
Among the eight patients who received embolization, the procedure worked in every case, with the agents reaching small distant vessels without getting stuck or causing the catheter to adhere to the vessel wall — a known risk with standard formulations. No procedure-related complications occurred. On follow-up imaging, all eight patients showed hematomas that were either stable or shrinking, none needed emergency surgery afterward, and all had a median discharge neurological score (GCS) of 15, which is normal. These results suggest that carefully diluted liquid embolic agents may offer better penetration while still remaining controllable during the procedure.
This research suggests that MMA embolization using diluted liquid embolic agents could be a viable minimally invasive option to help manage selected acute epidural hematomas — particularly in patients who may be at high surgical risk. However, the study involved only 9 patients at a single hospital with short-term follow-up, so the findings are very preliminary. The authors themselves emphasize that larger multicenter studies are needed before this approach can be broadly recommended or adopted as a standard treatment strategy.
Shen H, Qian Y, Hu J, Gao T, Sheng M, Qian X, et al.. (2026). Adjunctive middle meningeal artery embolization with low-viscosity liquid embolic agents for acute epidural hematoma: technical considerations and a case series.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1896356