Standalone embolization of a right sphenoid ridge meningioma. (A) Pretreatment contrast-enhanced MRI. (B) Angiography demonstrating the middle meningeal arterial supply. (C) Microcatheter delivery of Onyx-18 into the tumor vasculature. (D) Postembolization angiographic appearance. (E) MRI showing reduced tumor volume one year after embolization. Illustrative case from Yu et al. (2025), from a separate study rather than the systematic review by Odland et al.
Figure reproduced without modification from Yu D, Huang G, Shen J, Li Y, Xu J, Xu Z, Li J and Dai D. Multicenter evaluation of preoperative and standalone embolization in meningiomas. Frontiers in Oncology. 2025;15:1626753. Copyright 2025 Yu and colleagues. Licensed under CC BY 4.0.
Neurosurgery. 2026;99(4):746–759
Embolization is usually performed before meningioma resection to reduce tumor vascularity.
This review examines its potential as a treatment without immediate surgery or radiotherapy.
Published cases describe symptom improvement and tumor shrinkage, particularly in patients considered unsuitable for surgery.
The findings identify a possible therapeutic role, although the supporting evidence remains limited.
Objective
Assess clinical outcomes, radiographic response and complications following standalone meningioma embolization.
Methods
A PRISMA-based systematic review searched PubMed/MEDLINE and Embase in January 2025, supplemented by citation searching.
Standalone treatment was defined as embolization without resection or radiotherapy for at least two months. The authors identified 121 reported patients across 34 publications; 24 studies involving 67 patients provided follow-up information. Outcome-specific denominators varied because reporting was incomplete.
Main results
Among patients with documented outcomes:
- Symptomatic improvement occurred in 77% of the 44 symptomatic patients assessed.
- Tumor shrinkage was reported in 84% of 38 patients with radiographic response information.
- Mean reported tumor-size reduction was 31%, with a standard error of 7.3%, over 3–48 months in studies providing quantitative measurements.
- Mean last follow-up was 15 months, ranging from 2 to 72 months, among 59 patients with available data.
The review reported three major complications and one death; the fatal event involved hemorrhage following particle embolization. Some patients subsequently required repeat embolization, surgery or radiosurgery.
Interpretation
The results suggest that devascularization can produce sustained biological effects, potentially through ischemia and tumor necrosis. However, radiographic shrinkage does not establish durable tumor control.
The paper compares complication rates with those reported elsewhere for surgery, but these are indirect comparisons between different populations. They cannot establish that standalone embolization is safer than resection.
Limitations
Evidence consists predominantly of case reports and small series spanning approximately five decades. Techniques, embolic materials, follow-up and outcome definitions varied substantially.
Selection bias is particularly relevant: some patients avoided surgery because they improved after embolization, whereas patients whose planned surgery was canceled because of embolization-related complications were excluded. These criteria may favor positive outcomes.
Histological diagnosis and grade were not consistently available. The population was predominantly older but included a pediatric patient, so the pooled estimates are not exclusively adult.
Clinical takeaway
Standalone embolization may warrant multidisciplinary consideration for selected patients with substantial surgical risk or limited treatment options. The review supports prospective investigation; it does not establish equivalence to surgery, radiotherapy or surveillance, nor provide validated selection criteria.
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