Venous air embolism in consecutive balloon kyphoplasties visualised on CT imaging

We noted a large amount of intravenous gas during balloon kyphoplasty on CT imaging. Formal assessment to understand the extent, possible causes and implications was undertaken.

Ten consecutive cases of balloon kyphoplasty were performed under general anaesthesia in the prone position, on a single vertebral level using a two-step technique under combined fluoroscopic and CT guidance. CT of the affected vertebra was performed before, after, and intermittently during the procedure. In 2 cases delayed CT was carried out in the supine position.

Gas was seen on CT imaging, but not on conventional fluoroscopy. The gas is most likely to be air introduced during the procedure and was seen in the epidural and paravertebral venous plexus, posterior intercostal veins, renal veins, IVC and azygos vein. The average measured volume of gas seen on the post-procedure CT imaging was 1.07 mL, range 0.16-3.97 mL. There was no correlation of the measured amount of gas to the procedure duration or location, the use of a curette or the injected cement volume. Delayed CT in the supine position no longer showed air in the local venous system.

Balloon kyphoplasty is associated with the fluoroscopically invisible introduction of air into the vertebral and paravertebral veins and deep systemic veins and is likely to be much more extensive than identified on CT imaging. There is potential for serious air embolism in kyphoplasty and if there is a sudden deterioration in patient condition during the procedure the possibility of this complication needs to be considered.