Abstract No. 116 Ethanol Embolization of Refractory Head and Neck Arteriovenous Malformations with Onyx Treatment History

This study aimed to evaluate the outcomes of coil-assisted ethanol embolotherapy in recanalized head and neck arteriovenous malformations (HNAVMs) with dilated outflowing veins after Onyx treatment. Thirty-six patients with HNAVMs (18 females and 18 males with a mean age of 26.83 years) who experienced recurrence after Onyx embolization from October 2007 to October 2017 were included in this study. All patients underwent complete clinical and angiographic examinations. Further, each patient was classified based on the Schobinger stage before undergoing staged ethanol embolization. All patients were followed up for 5 years in-person at an interval of 3 months after discharge. The Kaplan–Meier method was used to perform the recurrence-free survival (RFS) analysis. Sixteen patients (44.4%) had Schobinger stage II HNAVMs, whereas the remaining patients had Schobinger stage III or IV (20/36 patients, 55.6%) HNAVMs. A total of 116 embolization procedures were performed, and coils were applied in 107 procedures (92.2%) among patients with dilated outflowing veins. The dose of absolute ethanol was 16.39 mL per procedure in patients with Schobinger II HNAVMs, and 22.45 mL per procedure in patients with Schobinger III and IV HNAVMs (P = 0.024, 95% confidence interval [CI]: 1.128-5.009). During the 3-month evaluation, complete response was observed in 13/36 patients (36.1%), and partial response was observed in 23/36 patients (63.9%). The 5-year RFS rate of patients who received Onyx treatment had improved 58.3% after ethanol embolization (P < 0.0001, 95% CI: 2.853-9.595). In patients with refractory HNAVMs, coil-assisted ethanol embolotherapy helped achieve promising outcomes in short- and long-term follow-ups with only acceptable complications. Although the treatment of recanalized AVMs after Onyx embolization remains a clinical challenge and lacks consensus, the present study provided evidence of ethanol's potency and safety as a treatment modality.