Paradoxical embolus across atrial septal defect and posterior circulation infarct in neurosurgical patients.

Paradoxical embolism through a patent foramen ovale or atrial septal defect is increasingly recognized in association with embolic strokes, with the advent of modern echocardiography. The authors describe two neurosurgical cases with such an anomaly that suffered nonfatal embolic stroke in the cerebellum. The patients developed posterior inferior cerebellar artery infarcts, which were managed conservatively and had no neurological deficits. They evaluate possible factors for emboli to occur in a perioperative neurosurgical setting and provide a brief review of literature on preoperative management of patients with this cardiac defect. Closure of cardiac shunts is warranted before non-emergent neurosurgical operations. During emergency craniotomies, proper precautions should be taken to reduce the incidence of venous air embolism and paradoxical embolism.