Middle Meningeal Artery Embolization Using Non-Adhesive Liquid Embolic Agents for Chronic Resistant Migraine: Interim Feasibility and Safety Analysis of a Prospective Single-Arm Trial

Background/Objectives: Chronic resistant migraine responds poorly to multiple classes of preventive therapy. The middle meningeal artery (MMA), along which nociceptive trigeminal fibers run, has been proposed as an interventional target. We report an interim feasibility and safety analysis of the first 10 patients in an ongoing prospective trial of MMA embolization with non-adhesive liquid embolic agents. Methods: Single-arm, open-label, multicenter, investigator-initiated trial at two centers (ClinicalTrials.gov NCT06848166; registered retrospectively). Of 318 patients assessed for eligibility, 16 (5.0%) met European Headache Federation criteria for resistant migraine and 10 were treated between October 2024 and November 2025; data cut-off was 5 September 2026. This interim analysis was not prespecified. Its main outcome, defined post hoc, was technical success—grade III or higher on the investigator-developed Saint Petersburg Arterial Dural Embolization Scale (SPADES)—reported per branch on an intention-to-treat basis and per patient (all four target branches); the registered primary efficacy endpoint, change in monthly migraine days at 12 weeks, is reported descriptively. Results: Of forty target branches, thirty were catheterized directly, six were filled retrogradely, and four were not embolized. Grade III or higher was achieved in 29 of 40 branches (72.5%; 95% CI 56.1–85.4) and in all four branches in four of ten patients (40%). The level reached by the catheter was related to branch tortuosity, and catheterizability of the parietal branch to the Adachi configuration. Anastomoses with the ophthalmic artery were present in 14 of 19 assessable arteries (73.7%). The embolic agent extended into the dural venous drainage in eight of ten patients without entering a sinus lumen. No serious procedure-related adverse event occurred (zero of ten; 95% CI 0–30.8); post-embolization headache lasting a median of 15 days occurred in nine patients, and all patients remained at modified Rankin Scale 0. Median monthly migraine days fell from 20.5 (IQR 18.0–22.5) at baseline to 8.0 (IQR 0.2–17.0) at 12 weeks, with a reduction of at least 50% in six of ten patients (60%; 95% CI 26–88); acute medication days fell in parallel. Conclusions: Bilateral MMA embolization with non-adhesive liquid embolic agents was technically feasible in this small series, which demonstrates initial procedural feasibility but cannot establish safety or efficacy. The clinical changes are uncontrolled and unblinded, cannot be separated from a placebo response, regression to the mean or reduced medication use, and require a sham-controlled trial.