Object To report the morbidity and long term results in the treatment of paragangliomas by transarterial embolization with ethylene vinyl alcohol (Onyx), either as preoperative or palliative treatment.

Methods Between September 2005 and 2012, 18 jugulotympanic, 7 vagal, and 4 carotid body paragangliomas (CBPs) underwent Onyx embolization, accordingly to our head and neck multidisciplinary team's decision. CBPs were embolized preoperatively. Jugulotympanic and vagal paragangliomas underwent surgery when feasible, otherwise palliative embolization was carried out alone, or in combination with radiotherapy or tympanic surgery in the case of skull base or tympanic extension. Treatment results, and clinical and MRI follow-up data were recorded.

Results In all cases, devascularization of at least 60% of the initial tumor blush was obtained; 6 patients underwent two embolizations. Post-embolization, 8 patients presented with cranial nerve palsy, with partial or complete regression at follow-up (mean 31 months, range 3–86 months), except for 2 vagal and 1 hypoglossal palsy. 10 patients were embolized preoperatively; 70% were cured after surgery and 30% showed residual tumor. 19 patients received palliative embolization, of whom 5 underwent radiotherapy and 3 received tympanic surgery post-embolization. Long term follow-up of palliative embolization resulted in tumor volume stability (75%) or extension in intracranial or tympanic compartments. Onyx embolization of CBPs resulted in more difficult surgical dissection in 2 of 4 cases.

Conclusions Onyx embolization is a valuable alternative to surgery in the treatment of jugulotympanic and vagal paragangliomas; tympanic surgery or radiosurgery of the skull base should be considered in selected cases. Preoperative Onyx embolization of CBPs is not recommended.