Delayed Sudden Blindness From Unilateral Ophthalmic Artery Vasospasm Following Endoscopic Sinus Surgery?

Abstract

Keywords: ophthalmic artery; vasospasm; iatrogenic; endoscopic sinus surgery; blindness

Endoscopic sinus surgery (ESS) is a generally benign, minimally invasive procedure used for management of paranasal sinus diseases, although complications may occur due to proximity of vital structures such as the brain, orbit and great vessels.1 The overall ESS major complication rate is 0.5-1%, of which orbital injury accounts for 0.09% due to direct trauma.2 We report a case of unilateral delayed sudden visual loss without orbital trauma observed intraoperatively or on post[1]operative imaging studies, following a seemingly routine endoscopic sinus surgery for chronic rhinosinusitis.

CASE REPORT

                   An 18-year-old lad with no significant medical history underwent ESS for bilateral chronic rhinosinusitis with nasal polyposis. (Figure 1 A-D) The surgery and recovery from anesthesia were uneventful. On the 12th hour post-operatively, the patient noted blurring of vision on the left. Ophthalmologic examination revealed hyperemic conjunctiva (Figure 2A) with visual acuity of counting fingers at 1 foot while fundoscopy showed retinal hemorrhages. Extraocular eye movements (EOM) and intraocular pressure (IOP) were normal (12mmHg). With an assessment of pre-retinal hemorrhages, 500 mg Tranexamic acid was intravenously infused, and a paranasal sinus (PNS) computed tomography (CT) scan and orbital magnetic resonance imaging (MRI) were requested. A few hours later, he complained of left eye pain with increasing intensity and further deterioration of vision. Repeat visual acuity testing showed light perception. There was now a constricted pupil, non-reactive pupillary light reflex, periorbital swelling and progression of conjunctival chemosis. (Figure 2B) The IOP of the left eye had increased to 30mmHg then progressed to 40mmHg with development of total visual loss and a lateral gaze limitation. With an impression of choroidal hemorrhage and retrobulbar hemorrhage, a lateral canthotomy relieved the eye pain.

               The contrast PNS CT scan with orbital cuts showed that the lamina papyracea was intact with no definite hemorrhagic collections in the intraconal or extraconal spaces of both orbits. (Figure 3A, B) A small hyper density along the lateral inferior margin of the left globe at the intraconal region with slight thickening of the anterior periorbital region represented the lateral canthotomy. The PNS MRI / magnetic resonance angiography (MRA) with orbital cuts showed retinal detachment and periorbital edema in the left eye. (Figure 4) A B-Scan ocular ultrasonogram showed retinal detachment and vitreous opacities. The diagnosis was ocular ischemic syndrome secondary to ophthalmic artery vasospasm, and the patient was given sublingual nitroglycerine and intravenous dexamethasone 8mg every 12 hours for 24 hours, with improvement of periorbital swelling. He was discharged after 12 days with no resolution of the unilateral visual loss.