Onyx plus stereotactic radiosurgery versus stereotactic radiosurgery alone in patients with cerebral arteriovenous malformations: A systematic review and meta-analysis.

INTRODUCTION

Stereotactic radiosurgery (SRS) is a primary treatment for cerebral arteriovenous malformations (AVMs). Onyx embolization is used before SRS to reduce AVM size, but its impact remains uncertain. This meta-analysis compares the efficacy and safety of Onyx + SRS versus SRS alone.

METHODS

A systematic search of PubMed, Cochrane Library, Scopus, Web of Science, and Embase, adhering to Cochrane guidelines, was conducted to identify studies comparing AVM obliteration rates following Onyx + SRS versus SRS. Data were pooled using a random-effects, inverse-variance model, with I2 assessing heterogeneity, and sensitivity analyses performed in R.

RESULTS

SRS alone had higher AVM obliteration rates (OR: 0.63, 95 % CI: 0.41-0.96, p = 0.030). No significant differences were found in post-SRS hemorrhage (OR: 1.37, 95 % CI: 0.63-3.01, p = 0.430), cyst formation (OR: 2.11, 95 % CI: 0.27-16.62, p = 0.477), or mortality (OR: 1.75, 95 % CI: 0.36-8.63, p = 0.490). The overall rate of post-SRS complications was 31.55 % (95 % CI: 23.36-39.75).

CONCLUSION

This meta-analysis indicates that SRS alone achieves higher AVM obliteration rates than combined Onyx embolization and SRS, without reducing hemorrhage risk or improving safety. Therefore, routine Onyx embolization prior to SRS is not supported by current evidence, suggesting a need for selective application and further investigation to identify optimal treatment strategies. Takeaway message: This meta-analysis found that SRS alone achieved a higher AVM obliteration rate compared to combined Onyx embolization plus SRS, with a pooled OR of 0.63 (95 % CI: 0.41-0.96; p = 0.030). No significant differences were observed between groups in post-SRS hemorrhage rates (OR: 1.37, 95 % CI: 0.63-3.01; p = 0.430), cyst formation (OR: 2.11, 95 % CI: 0.27-16.62; p = 0.477), or mortality (OR: 1.75, 95 % CI: 0.36-8.63; p = 0.490). The overall rate of post-SRS complications was 31.55 % (95 % CI: 23.36-39.75).These findings suggest that routine Onyx embolization prior to SRS does not improve efficacy or safety and should be reserved for selected cases.