External Ophthalmic Arterial Re-Anastomosis to External Carotid System After Swine Optic Nerve Transection

Abstract

Purpose: : To study the feasibility of ocular reperfusion after vascular anastomosis in swine optic nerve transection.

Methods: : Experiment I (ex vivo perfusion). Under the general anesthesia, baseline ERG and fluorescein angiography was performed. Swine eye was enucleated or exenterated and perfused ex vivo using a specially-designed pulsatile Krebs perfusate. Ocular viability was evaluated using ERG with scotopic conditions. Experiment II (in vivo perfusion). Under the general anesthesia, external maxillary artery was secured in facial area. Its proximal end was cut-down and anastomosed with heparin-filled specially-designed silastic tube. Swine external ophthalmic artery was explored between inferior and lateral extraocular muscles (EOM) and the distal end of external ophthalmic artery was cut-down and anastomosed with silastic tube. Both silastic tubes from external ophthalmic artery and external maxillary artery was connected so as external maxillary artery supplied external ophthalmic artery. Optic nerve was posteriorly transected near orbital apex. Eyeball was exenterated or enucleated after all EOMs were detached.

Results: : Scotopic ERG was maintained until two hours after ex vivo reperfusion. Ophthalmic arterial re-anastomosis to external maxillary artery was successfully performed in porcine eyes.

Conclusions: : ERG was maintained two hours after ocular reperfusion of swine eyes ex vivo not in vivo. As compared to enucleated eye, surgical feasibility of external ophthalmic arterial re-anastomosis to external carotid system was greater in exenterated eye.

Keywords: optic nerve • optic flow • visual search