Others follow. We lead.

Most proven product for MMAe1-5

Onyx™ LES is backed by the largest body of randomized clinical evidence in cSDH, with two landmark trials that produced Level 1 evidence that continues to shape the management of cSDH patients.

Onyx LES1-5

TRUFILL™*6

Squid™*7

Particles8

Coils

Approved for
cSDH in the US

Approved Approved Approved Not approved Not approved

cSDH patients
studied in RCT

1,737

376

310

342

0

Onyx LES1-5

Approved for
cSDH in the US

Approved

cSDH patients
studied in RCTs

1,737

TRUFILL™*6

Approved for
cSDH in the US

Approved

cSDH patients
studied in RCTs

376

Squid™*7

Approved for
cSDH in the US

Approved

cSDH patients
studied in RCTs

310

Particles8

Approved for
cSDH in the US

Not approved

cSDH patients
studied in RCTs

342

Coils

Approved for
cSDH in the US

Not approved

cSDH patients
studied in RCTs

0



Setting the standard with Level 1 evidence1.

Long before MMA embolization became today's standard, Onyx™ LES was building the clinical experience, evidence, and innovation that continues to shape the field.



EMBOLISE1

Setting the standard with Level 1 evidence.

A prospective, randomized, multicenter trial evaluating adjunctive MMA embolization with Onyx™ LES in patients with symptomatic subacute or chronic subdural hematoma.

  • Prospective | Randomized | Multicenter
  • 400 patients 
  • 100% Onyx™ LES 
  • 63% reduction in hematoma recurrence 
  • 0% Onyx related AEs up to 180 days 
  • 0% Ipsilateral visual complications up to 90 days

EMMA-Can3

Strengthening the evidence with independent validation.

An investigator-initiated, prospective, randomized clinical trial evaluating adjunctive MMA embolization with Onyx™ LES following surgical drainage for chronic subdural hematoma.

  • Investigator initiated | Prospective | Randomized | Multicenter
  • 192 patients
  • Number needed to treat: 4.2
  • 84.6% reduction in symptomatic recurrence 
  • 71.7% reduction in radiographic recurrence


Seal the Source. Treat the Disease.


  1. Davies JM, Knopman J, Mokin M, et al. Adjunctive middle meningeal artery embolization for subdural hematoma. N EnglJ Med 2024;391:1890-900. 
  2. EMBOLISE II: Davies, JM; Knoman J; et al. The EMBOLISE Study Non-Surgical Cohort: Preliminary Results From the Observation Cohort. American Stroke Association's 2026 International Stroke Conference (ISC), New Orleans. Presented on February 5, 2026.
  3. Management of Chronic Subdural Hematoma With Adjunctive Embolization of Middle Meningeal Artery: Research Summary. JAMA. Published online April 30, 2026. doi:10.1001/jama.2026.4965 
  4. OTEMACS: Ng, Sam; et al. Chronic subdural hematoma and MMA embolization: OTEMACS trial. SLICE Next Frontiers, Presented on April 2, 2025.
  5. Liu, J., Ni, W., Zuo, Q., Yang, H., Peng, Y., Lin, Z., Li, Z., Wang, J., Zhen, Y., Luo, J., et al. (2024). Middle meningeal artery embolization for nonacute subdural hematoma. New England Journal of Medicine, 391(20), 1901–1912. https://doi.org/10.1056/NEJMoa2401201 
  6. Kellner CP, Rai AT, Shoirah H, et al. Middle Meningeal Artery Embolization With n-Butyl Cyanoacrylate in Patients With Chronic Subdural Hematoma: A Randomized Clinical Trial. JAMA Neurol. Published online June 15, 2026. doi:10.1001/jamaneurol.2026.1542 
  7. Fiorella, D., Monteith, S. J., Hanel, R., Atchie, B., Boo, S., McTaggart, R. A., Zauner, A., Tjoumakaris, S., Barbier, C., Benitez, R., Spelle, L., Pierot, L., Hirsch, J. A., Froehler, M. T., Arthur, A. S., STEM Investigators, & Holtmannspötter, M. (2025). Embolization of the middle meningeal artery for chronic subdural hematoma. New England Journal of Medicine, 392(9), 855–864. https://doi.org/10.1056/NEJMoa2409845 
  8. Shotar E, Mathon B, Salle H, Rouchaud A, Mounayer C, Bricout N, Lejeune JP, Janot K, Amelot A, Naggara O, Roux A, Goutagny S, Guédon A, Houdart E, Brunel H, Hak JF, Troude L, Dufour H, Bernat AL, Tuilier T, Bresson D, Apra C, Fouet M, Escalard S, Chauvet D, Premat K, Lebbah S, Dechartres A, Clarencon F; EMPROTECT Investigators. Meningeal Embolization for Preventing Chronic Subdural Hematoma Recurrence After Surgery: The EMPROTECT Randomized Clinical Trial. JAMA. 2025 Jul 8;334(2):127-135. doi: 10.1001/jama.2025.7583. PMID: 40471557; PMCID: PMC12142473.

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