Timing of Middle Meningeal Artery Embolization and Surgery: Analysis of the EMBOLISE Trial.

BACKGROUND

The EMBOLISE trial (The Embolization of the Middle Meningeal Artery With Onyx Liquid Embolic System in the Treatment of Subacute and Chronic Subdural Hematoma) demonstrated that middle meningeal artery embolization as an adjunct to surgical drainage reduces recurrence of symptomatic subacute and chronic subdural hematomas. We performed a subgroup analysis of the EMBOLISE surgical cohort to determine how the timing of embolization relative to surgery impacted various outcomes.

METHODS

We performed a post hoc subgroup analysis to examine the association of the timing of embolization relative to surgery with the primary end point (hematoma reoperation within 90 days), secondary end points (clinical and radiographic outcomes), and safety end points (serious adverse events, neurological death, all-cause death, and stroke).

RESULTS

Middle meningeal artery embolization before surgery (embolization-first group) and middle meningeal artery embolization after surgery (surgery-first group) were performed in 107 and 78 patients, respectively. Demographics and baseline clinical characteristics of the 2 groups were similar. The core laboratory confirmed the procedure to be successful in all patients with similar rates of distal penetration of Onyx into middle meningeal artery branches at the end of the embolization procedure in both groups (49.5% and 48.7%, respectively, P>0.99). Six of 103 patients in the embolization-first group (5.8%) and none in the surgery-first group needed reoperation within 90 days (analysis with observed data, P=0.08). Hematoma volumes at 90 and 180 days were similar except for lower hematoma thickness in the surgery-first group (2.3±3.0 mm versus 4.4±5.6 mm, P=0.03) at 180 days. Clinical and safety outcomes at 30, 90, and 180 days were similar.

CONCLUSIONS

Performing surgical drainage before embolization in patients with subacute and chronic subdural hematomas may help minimize treatment failures and enhance hematoma resolution.

REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04402632.