Horner's syndrome caused by the first rib fracture sustained during coronary artery bypass grafting: a case report and literature review.

Background: Horner's syndrome is a rare complication of cardiovascular surgery. A bone fragment and hematoma due to rib fracture after cardiac surgery may cause injury to the brachial nerve plexus and sympathetic nerve trunk, leading to neurologic disorders and Horner's syndrome. However, few reports have revealed the etiology of Horner's syndrome after cardiovascular surgery based on imaging. Herein we present a case in which a plain CT scan confirmed the etiology of Horner's syndrome after coronary artery bypass grafting (CABG), reviewing 139 CABG cases retrospectively in our hospital and 6 case reports of Horner's syndrome associated with cardiovascular surgery.

Case presentation: A 69-year-old woman with a history of percutaneous coronary intervention and total abdominal hysterectomy with bilateral salpingo-oophorectomy had chest pain on exertion. Coronary angiography showed severe triple vessel disease. She underwent off-pump coronary artery bypass grafting (CABG). A median sternotomy was performed, and the split sternums were widened using a sternal retractor. The bilateral internal thoracic arteries were harvested. A triple CABG was performed. She had left shoulder pain after surgery. She complained of anhidrosis involving the left face and hyperhidrosis involving the right face from postoperative day (POD) 6. Left ptosis and blurry vision appeared after discharge from the hospital, for which she saw a neurologist in our hospital on POD 48. Miosis could not be clearly confirmed. She was diagnosed with Horner's syndrome. A plain CT scan revealed displaced fractures of the bilateral first ribs and left second rib. The bone fragment of the left first rib head was displaced 3 mm anteriorly compared to the left first rib head before surgery, which suggested that the fragment affected the stellate ganglion in the sympathetic trunk. The patient had regular follow-up evaluations. The anhidrosis persisted, but the ptosis improved, and the miosis was not confirmed at the 6-month follow-up evaluation.

Conclusions: We should recognize that Horner's syndrome is one of the complications of cardiovascular surgery, especially CABG. Fracture of the first rib head with a displaced bone fracture was shown to be a contributor to ipsilateral Horner's syndrome. When symptoms of Horner's syndrome and other neurologic symptoms are noted after open heart surgery, a plain CT examination should be obtained.