A Case of Medial Rectus Muscle Injury and Optic Nerve Transection Developed During Functional Endoscopic Sinus Surgery

Kim, Hyun Cheol; Kim, Jong Hyun; Lee, Se Youp

Abstract

PURPOSE
We encountered a patient with right medial rectus muscle injury and optic nerve transection that had developed during functional endoscopic sinus surgery(FESS) and thus, report the present case with a literature review. METHODS: A 59-year-old woman was transferred to the present hospital due to the inability to adduct the right eye to the midline, exotropia, and loss of vision after she had underwent functional endoscopic sinus surgery due to bilateral chronic paranasal sinusitis and polyps in a local ENT clinic. RESULTS: The right eye could not perceive the light. The patient showed 40 exodeviation by the Hirschberg's test and marked limitation on adduction. Flame-shaped retinal hemorrhages and a cherry-red spot were present in the posterior pole on the fundus examination using slit-lamp biomicroscopy. Orbital computerized tomography showed the evidence of medial rectus muscle injury and complete transection of the optic nerve. Postoperative endoscopic paranasal sinus examination showed the evidence of complete transection of the ophthalmic artery and vein. CONCLUSIONS: Clinicians should have thorough understanding of the anatomy of the paranasal sinus, especially, the ethmoid sinus and orbit in order to prevent serious complications as in our case. Endoscopic examination of the nasal cavity and orbital computerized tomography must be performed before surgery for accurate diagnosis. Furthermore, experienced surgeons who would perform this type of surgery with great precision could prevent permanent loss of vision through extraocular muscle injury or optic nerve transection.