Optic Nerve Microvascular Decompression for Carotid Dolichoectasia

Abstract

Vascular compression of the optic nerve in a patient with rapid monocular vision loss with otherwise negative diagnostic workup is a rare, but controversial dilemma. The literature is conflicted, advocating for either timely surgical decompression to preserve vision1, 2, 3, 4, 5, 6 or observation only given the prevalence of asymptomatic vascular compression and observed arrest of visual decline.7, 8, 9, 10 The most frequently reported sources of symptomatic compression are unruptured aneurysms and dolichoectatic vasculature,1, 2, 3, 4, 5, 6 with recent consensus reached over a need for extensive perioperative ophthalmologic evaluations and follow-up. We present an illustrative case for microvascular decompression of the prechiasmatic optic nerve. Video footage of the operative management of microvascular optic nerve compression is exceedingly rare.^5,6 A 50-year-old man with a past medical history of hypertension and substance use presented with a 1-week history of progressive right nasal hemianopsia (Video 1). After a negative stroke workup, magnetic resonance imaging of the brain showed prechiasmatic displacement of the right optic nerve by the right supraclinoid internal carotid artery. Formal cerebral arteriography showed a left-sided fetal posterior cerebral artery and patent vasculature without a causative lesion. Given isolated right eye symptoms and rapid progression, a right orbitozygomatic craniotomy for microvascular decompression was recommended. The patient consented to the procedure and to the publication of his image. Intraoperatively, a right calcified dolichoectatic supraclinoid internal carotid artery was found to be severely displacing and tethering its ipsilateral optic nerve. Optic canal deroofing, detethering of the optic nerve, and polytetrafluoroethylene (Teflon) patch placement was performed to achieve this decompression. His postoperative course was uncomplicated; only mild improvement of his visual symptoms was noted at 1- and 3-month follow-up. Formal acuity and computerized assessments of vision and extensive follow-up are critical for evaluating the true clinical outcome of patients with microvascular optic nerve compression.