Multifocal Stroke From Ozone Gas Emboli.

A 34-year-old man with chronic neck pain was treated with regular cervical paravertebral ozone injections. After his last injection, he experienced a syncopal episode and, upon awakening, was found to have ataxia, aphasia, hemiparesis, and left sixth nerve palsy. Computed tomographic angiography demonstrated intra-arterial gas in the right vertebral artery; multiple posterior circulation infarcts were seen on brain MRI. This case illustrates the potential dangers of paravertebral injections of ozone.