Embolization of Intracranial Arteriovenous Malformations Using Onyx in 53 Patients

Endovascular embolization is one of the main modalities in the treatment of brain arteriovenous malformations (AVMs). Onyx (ethylene-vinyl alcohol copolymer) is a new embolic agent with some advantages of slow injection and better control of penetration.
To report our experience in the embolization of brain AVMs with Onyx.
Patients and From August 2012 to October 2014, 53 consecutive patients harboring brain AVM were treated with Onyx as the sole embolic agent during 85 procedures. There were 27 males and 26 females with a mean age of 27.2 years (range, 8 - 65 years).
The presenting symptom was headache in 25 (47%), neurological deficit in 18 (35%), and seizure in ten (18%) patients. According to the Spetzler-Martin grading scale, three of the AVMs were ranked as grades I, 11 as grade II, 22 as grade III, 14 as grade IV, and three as grade V. An average of 1.8 feeding pedicles were embolized in each case, whereas a mean of 2.23-mL Onyx was used per patient. Initial complete obliteration at the end of all embolization procedures was achieved in 11 patients (20.08%). The rate of complete embolization at 6-month follow-up was 15%. After completion of embolization, the neurologic status was unchanged or improved in 46 (87%) patients. We observed treatment-related neurologic deficit in seven (13%) patients, of whom five were permanent (10%). There was no procedure-related death.
Our experience with Onyx used for embolizing AVMs was satisfactory. Controlled injections that protect the draining veins make the therapy safe even in complex AVMs.