Transient Postoperative Myoclonus Following Hypothermic Circulatory Arrest

Neurologic complications are a risk of aortic arch surgery performed with hypothermic circulatory arrest. Stroke, encephalopathy, and seizures are well-recognized complications, whereas postoperative movement disorders are rarely reported.

A 72-year-old male underwent elective ascending aorta and hemiarch replacement under hypothermic circulatory arrest (28 minutes, nadir 28.9 °C) with bilateral antegrade cerebral perfusion and stable cerebral oximetry readings. During postoperative weaning from sedation, the patient developed persistent bilateral myoclonus, diffuse rigidity, and suspected eyelid apraxia, present at rest and unaffected by voluntary movement. Although a stroke code was activated, computed tomographic angiography of the head and neck was normal. Laboratory evaluation showed mild hypocalcemia without other metabolic derangements. Electroencephalography and magnetic resonance imaging were not performed. The patient was treated with intravenous levetiracetam and calcium supplementation. The movements resolved by postoperative day 3, and the patient was discharged home neurologically intact on day 5.

This case demonstrates a transient form of postoperative myoclonus distinct from Lance-Adams syndrome. Recognition of atypical movement disorders after hypothermic circulatory arrest may help clinicians avoid unnecessary escalation of therapy and provide reassurance regarding the potential for complete recovery.