Arteriovenous malformations treated by stereotactic radiosurgery - Review of an Australian single centre's experience

Linear accelerator (LINAC) stereotactic radiosurgery (SRS) is a specialised treatment used for various brain conditions, including arteriovenous malformations (AVMs). This paper investigates the obliteration rate of AVMs treated by the LINAC-based facility at Prince of Wales Hospital, defines factors influencing obliteration rate, time to obliteration and complications post-SRS. A retrospective audit review of patient notes sourced from electronic medical records was conducted. During the study period 219 patients received treatment, of which the final status of 136 AVMs was known. Overall obliteration rate was 75.7 %, with obliteration rates of 5 %, 30 % and 46 % at one, three and four years, respectively. Post analysis, a radiosurgery dose of ≥ 18 Gray (Gy) was predictive of achieving obliteration (Odds Ratio (OR) 4.2, 95 % Confidence Interval (CI) 1.61-10.83, p = 0.003) whilst a nidus size of 3-6 cm was less likely of achieving obliteration (OR 0.2, CI 0.10-0.57, p = 0.001). Multivariate analysis showed a radiosurgery dose of ≥ 18 Gy remained predictive (OR 4.7, CI 1.69-13.25, p = 0.003) and a nidus size of 3-6 cm remained less likely to achieve obliteration (OR 0.2, CI 0.10-0.57, p = 0.001). Females were predictive of developing temporary complications post-SRS in multivariate analysis (OR 2.8, CI 1.24-6.13, p = 0.013), and having > 1 SRS session was predictive of developing permanent complications post-SRS (OR 7.1, CI 2.44-20.53, p < 0.001). The obliteration rate achieved from our study and the predictive nature to achieve obliteration with a radiosurgery dose of ≥ 18 Gy is comparable to existing literature including that using the Gamma-Knife system.