Iatrogenic Horner's syndrome in an experimental pig.

An adult domestic female pig (Sus scrofa) exhibited clinical signs of right-sided Horner's syndrome after experimental placement of a woven aortic stent followed by aortic catheterization. The clinical signs included a miotic pupil, ptosis of the upper eyelid, prolapse of the nictitating membrane, and enophthalmos. Necropsy revealed a large mass in the right midcervical region that encased or was in contact with the carotid artery, internal jugular vein, and vagus nerve. Closer evaluation of the mass revealed that it was a small piece of surgical suture material that was embedded within the lumen of the carotid artery. This extrinsic material served as a nidus for an inflammatory reaction involving the vagus nerve.