Introduction Subacute/chronic subdural hematomas are common and frequently recur after surgical evacuation..

Aim of Study The effect of embolization of the middle meningeal artery on the need for repeat surgery has not been rigorously studied

Methods EMBOLISE is a multicenter, prospective, randomized, interventional, adaptive design trial of middle meningeal artery embolization combined with surgical evacuation of the subdural clot compared to surgery only. The primary endpoint was the rate of hematoma recurrence/progression requiring repeat surgical drainage.

Results A total of 197 patients were assigned to the treatment group and 203 to the control group. The absolute risk of the primary endpoint was 4.1% [1.8%, 7.8%] in the embolization group vs. 11.3% [7.3%, 16.5%] in the surgery only group (relative risk 0.36 [0.11, 0.80], P = 0.008). The secondary endpoint of deterioration in neurologic function (defined as having mRS < 3 at baseline and ≥ 3 at 90 days or having ≥ 3 at baseline and having an increase of ≥ point at 90 days) occurred in 11.9% vs. 9.8%, respectively. No adverse events within 90 days were related to Onyx. The 30- and 90-day rate of serious adverse events, including death, were similar in both arms.

Conclusion In patients with symptomatic subacute/chronic subdural hematoma requiring surgical drainage, adjunctive middle meningeal artery embolization was associated with a lower rate of hematoma recurrence/progression requiring repeat surgical drainage, without any increase in adverse events. Adjunctive middle meningeal artery embolization should be considered for patients presenting with subacute/chronic SDH requiring surgical evacuation.

ClinicalTrials. gov number NCT04402632

Disclosure of Interest yes Funded by medtronic, with consulting agreements for Drs. Knopman, Davies, and Siddiqui.