Stereotactic radiosurgery for arteriovenous malformations after Onyx embolization: a case-control study

Area of Science:

• Neurosurgery
• Interventional Radiology
• Radiation Oncology

Background:

• Onyx (ethylene-vinyl alcohol copolymer) is a common liquid embolic agent for intracranial arteriovenous malformations (AVMs).
• Stereotactic radiosurgery (SRS) is a treatment option for AVMs, particularly those unsuitable for conventional surgery.

Purpose of the Study:

• To evaluate the safety and efficacy of SRS in patients with AVMs previously treated with Onyx embolization.
• To compare obliteration rates and complication profiles between patients who underwent SRS with prior Onyx embolization and those who underwent SRS alone.

Main Methods:

• A case-control study matched 25 patients with prior Onyx embolization to 50 patients without embolization.
• Propensity score matching was used to control for variables including age, sex, AVM characteristics, and SRS parameters.
• Obliteration rates and complications (adverse radiation effects, hemorrhage, seizures, mortality) were analyzed.

Main Results:

• Onyx embolization reduced AVM size in 18 cases.
• Total obliteration rates after SRS were 24% in the embolization group versus 40% in the no-embolization group (not statistically significant).
• No statistically significant differences were observed in obliteration rates or complication incidence between the two groups.

Conclusions:

• Onyx embolization is effective in reducing AVM size prior to SRS.
• This study found no significant increase in complications or difference in obliteration rates when SRS is performed after Onyx embolization compared to SRS alone.
• Onyx embolization appears to be a safe and potentially beneficial adjunct to SRS for AVM management.