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Onyx Embolization Material Extrusion in the Middle Ear.

This 50-year-old man presented with right sided ear fullness and intermittent ear pressure with hearing loss 6 years after staged embolization of a right temporal arteriovenous malformation (AVM). On initial embolization, a small perforation of the middle meningeal artery was encountered and the artery was completely occluded with Onyx-18. Following two subsequent embolizations with Onyx-18 for the anterior temporal vasculature, he underwent craniotomy with resection of AVM through an orbitozygomatic approach with no postoperative complications. Right hemotympanum was noted on examination. A myringotomy demonstrated dried blood in the middle ear space and the patient was started on topical antibiotic and steroid drops in attempts to dissolve remaining middle ear blood. Repeat magnetic resonance imaging (MRI) was obtained showing no regrowth. See Figure 1A–C. After the myringotomy healed the patient continued to have decreased hearing and aural fullness with the continued appearance of hemotympanum. He underwent a mastoidectomy with middle ear exploration. Gray thick material appearing like steel wool was encountered filling the entire middle ear space. The material was adherent to the incus, stapes, as well as the horizontal segment of the facial nerve and was meticulously dissected off of the ossicles and facial recess with a small amount left on the horizontal segment of the facial nerve. Figure 2 shows the intraoperative images and histologic appearance of the embolization material. Bone conduction thresholds were normal before and after surgery. Air-conduction thresholds were worse by 30 dB at 250 Hz and 20 dB at 15 dB at 500 Hz (Fig. 1D). At other frequencies they were within 10 dB of the preoperative levels. After surgery the tympanic membrane had a persistent hemotympanum appearance suggesting additional extravasated material in the middle ear. The patient was offered additional imaging but refused as he was not interested in further intervention.