Introduction Treatment of brain arteriovenous malformations (BAVMs) is achieved by embolization, surgery, radiosurgery or any combination of these modalities. The aim of endovascular management of BAVMs before surgical resection is to minimize intraoperative blood loss, to occlude the entire BAVM or at least minimize the size of the nidus. Endovascular treatment is achieved by using n-butyl cyanoacrylate (n-BCA) or Onyx embolic agent.

Methods 14 Onyx and 15 n-BCA cases who were treated via endovascular procedures were randomly selected from 2003 to 2009 and were retrospectively analyzed. We began by comparing patient demographics, complication rates, Spetzler–Martin grading scale, BAVM volumes, pre- and post-embolization volumes, contrast loads, radiation times, as well as the number of feeder arteries. Volume of the nidus was calculated after three angiographic diameters of the lesion were obtained. The horizontal and vertical diameters were obtained from the anteroposterior projection and the longitudinal diameter from the lateral projection. We considered the BAVM to take an ellipsoid shape and we used Pasqualin method in calculating the volume of the BAVM: V= (wxhxl)/2

Results The mean pre-embolization nidal volume for Onyx and n-BCA cases were 5.59±4.84 cm³ and 4.11±4.30 cm³, respectively. No significant statistical difference between Onyx and n-BCA pre-embolization volumes was observed. The mean post-embolization volume for Onyx and n-BCA were 2.68±2.72 cm³ and 1.68±1.38 cm³, respectively. The per cent of obliteration of the BAVM was observed to be 71% in Onyx cases compared with n-BCA cases, which was 62.5% (p=0.2). Contrast load was observed to be higher in n-BCA cases compared with Onyx cases (p=0.8). However, fluoroscopy time was observed to be significantly higher in Onyx cases compared with n-BCA cases (P=0.0009). On the other hand, patients treated with Onyx as the sole embolic agent had fewer staged embolizations compared with n-BCA patients.

Conclusion The purpose of our study is to report our experience in using Onyx versus n-BCA and report our anatomic and clinical results accomplished using these two forms of treatment. Both modalities of treatment are comparable with regard to percentage of obliteration of the BAVM. However, Onyx requires a fewer number of staged embolizations to achieve the same degree of obliteration as one would achieve with n-BCA.