Management of Chronic Subdural Hematoma With Adjunctive Embolization of Middle Meningeal Artery: Research Summary

# Management of Chronic Subdural Hematoma With Adjunctive Embolization of Middle Meningeal Artery: Research Summary *Published: 2026 May 26* Management of Chronic Subdural Hematoma With Adjunctive Embolization of Middle Meningeal Artery: The EMMA-Can Randomized Clinical Trial. Shankar JJS(1)(2)(3), Alcock S(1), Kashani N(1), Darsaut T(4), Wang BH(5), Dos Santos MP(6), Milot G(7), O'Kelly C(4), Kelly ME(8), Iancu D(9), Cora A(10), Marotta T(11), van Adel B(12), Kishore K(5), Drake B(13), Lesiuk H(13), Carrondo-Cottin S(7), Rempel J(14), Ahmed U(8), Chaalala C(15), Silvaggio J(16), Kaderali Z(17), McEachern J(1), Salam MSA(16), Sinha N(18), Marin R(1), Leung YS(1)(19), Balshaw R(19), Fleetwood I(20), Jiang D(19), Menon BK(21), Singh N(22), Zeiler FA(16)(23)(24); EMMA-Can investigators. Collaborators: McDonald P, Drapeau A, Kazina C, Berrington N, Kaufmann A, Beiko J, Almojuela A, Dhaliwal P, Annayappa S, Dian J, Gomez A, Huang B, Blackwood B, Trivedi R, Ayroso M, Shankar I, Algird A, Larrazabal R, Son M, Martyniuk A, Jeganathan K, Fahed R, Zur G, Fageeh A, Diouf A, Hira R, Cooper S, Shenassa S, Schwarz BA, Mikhael N, Villeneuve K, Mehta R, Chanthavisouk S, Chow M, Bhattacharya S, Gaucher S, Peeling L, Kashani N, Hunter G, Ahmed U, Gardner A, Sylvain N, Tyson C, Grosskleg J, Foster K, Targerson S, Jabre R, Chakir S, Gevry G, Weeks A, Pickett G, MacMillan J, Pereira VM, Spears J, Liu E, Stalker C. Author information: (1)Department of Radiology, University of Manitoba, Winnipeg, Canada. (2)Department of Human Anatomy and Cell Sciences, University of Manitoba, Winnipeg, Canada. (3)Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada. (4)Section of Neurosurgery, Department of Surgery, University of Alberta, Edmonton, Canada. (5)Section of Neurosurgery, Department of Surgery, McMaster University, Hamilton, Ontario, Canada. (6)Department of Radiology, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada. (7)Section of Neurosurgery, Department of Surgery, CHU de Québec - Université Laval, Quebec City, Quebec, Canada. (8)Section of Neurosurgery, Department of Surgery, University of Saskatchewan, Saskatoon, Canada. (9)Department of Radiology, Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada. (10)Department of Radiology, Dalhousie University, Halifax, Nova Scotia, Canada. (11)Department of Radiology, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. (12)Section of Neurology, Department of Internal Medicine, McMaster University, Hamilton, Ontario, Canada. (13)Section of Neurosurgery, Department of Surgery, University of Ottawa, Ottawa, Ontario, Canada. (14)Department of Radiology, University of Alberta, Edmonton, Alberta, Canada. (15)Section of Neurosurgery, Department of Surgery, Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada. (16)Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada. (17)Section of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, Canada. (18)Section of Neuropathology, Department of Pathology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada. (19)College of Community and Global Health, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada. (20)Section of Neurosurgery, Department of Surgery, University of British Columbia, Victoria, Canada. (21)Section of Neurology, Department of Internal Medicine, University of Calgary, Calgary, Alberta, Canada. (22)Section of Neurology, Department of Internal Medicine, University of Manitoba, Winnipeg, Canada. (23)Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden. (24)Pan Am Clinic Foundation, Winnipeg, Manitoba, Canada. ## IMPORTANCE Chronic subdural hematomas commonly recur after surgical drainage. The effect of adjunctive embolization of the middle meningeal artery (EMMA) on recurrence risk remains unclear. ## OBJECTIVE To evaluate whether EMMA as an adjunct to surgical drainage reduces chronic subdural hematoma recurrence compared with surgery alone. DESIGN, SETTING, AND PARTICIPANTS This trial was a randomized, open-label, blinded-end point trial involving adults with unilateral, symptomatic chronic subdural hematoma (≥10 mm) undergoing surgical drainage across 9 tertiary care centers in Canada between August 2021 and April 2025. INTERVENTION: EMMA using a liquid embolic agent (Onyx-18) within 72 hours after surgical drainage vs a control group that did not receive EMMA after surgical drainage. MAIN OUTCOMES AND MEASURES Primary outcome was symptomatic recurrence of chronic subdural hematoma detected on computed tomographic (CT) scan at 90 days (range, 60 to 120 days). Secondary outcomes included radiographic recurrence of chronic subdural hematoma, 90-day mortality, and serious adverse events. The last date of follow-up was July 27, 2025. ## RESULTS Of 192 randomized participants, 186 (mean age, 71.8 years; 136 male [73%]) completed the trial (93 per group). The primary outcome of symptomatic recurrence of chronic subdural hematoma detected on CT scan occurred in 4 participants (4.3%) in the EMMA group vs 26 patients (28%) in the control group (risk difference, -23.7; 95% CI, -34.1 to -13.9; P < .001). Radiographic recurrence occurred in 13 participants (14%) in the EMMA group vs 46 patients (49.5%) in the control group. Mortality was 4.3% vs 1.1%; serious adverse events occurred in 8.6% vs 5.4%, respectively. CONCLUSIONS AND RELEVANCE Adjunctive EMMA after surgical drainage significantly reduced symptomatic recurrence on CT scan of unilateral chronic subdural hematoma at 90 days compared with surgery alone. ## TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT04750200. DOI: 10.1001/jama.2026.4910 DOI: 10.1001/jama.2026.4965