Gamma Knife radiosurgery for brain arteriovenous malformations – a single-center experience

Abstract

Background

Gamma Knife stereotactic radiosurgery (SRS) has emerged as a non-invasive and effective treatment for brain arteriovenous malformations (AVM), particularly in cases where surgical resection is not feasible. The factors influencing AVM obliteration following Gamma Knife radiosurgery remain incompletely understood and differing results across studies indicate the need for further research. This study reviews a single center’s 20-year experience with Gamma Knife radiosurgery for AVMs, evaluating factors associated with successful treatment outcomes.

Methods

A retrospective analysis was conducted on 241 patients treated with Gamma Knife SRS for intracranial AVMs at University Hospital Center Zagreb between 2004 and 2021. Patient demographics, AVM characteristics, prior treatments, radiosurgical parameters, and clinical outcomes were analyzed. AVM obliteration was assessed using MR angiography and digital subtraction angiography. Binary logistic regression and Cox regression analysis were performed to identify factors associated with treatment success and shorter time to obliteration.

Results

AVM obliteration was achieved in 171 patients (71%), with a mean time to complete obliteration of 3 years. Higher prescription doses correlated with increased obliteration rates (p < 0.05), as did hemispheric AVM location (p < 0.05) while smaller nidus volumes were associated with faster obliteration times (p < 0.05). 75.5% of previously embolized AVMs achieved obliteration vs 68.2% of non-embolized AVMs, however the difference was not statistically significant. The introduction of cone beam CT angiography in treatment planning improved obliteration rates (69.1% to 75.8%), though statistical significance was not reached. The overall complication rate was 15.4%, with 5.8% experiencing post-SRS hemorrhage.

Conclusion

Higher prescription doses correlated with improved obliteration rates, and smaller AVMs achieved faster obliteration. The use of additional imaging modalities in treatment planning possibly contributed to non-inferior obliteration rates in previously embolized AVMs.