Surgeons from Ohio State University report a single case of neurologic symptoms from air trapped in the spine. The 43-year-old woman had a steroid injection for chronic low back pain (LBP) and leg pain.
The surgeon inserted the needle into the epidural space using fluoroscopy to guide the procedure. The epidural space is located between the vertebral bone and the spinal canal and contains veins, arteries, and fat. Fluoroscopy is a special X-ray imaging used during surgery to help the surgeon see inside the patient.
The patient had increased back and leg pain right away after the injection. Both legs hurt and she noticed weakness in the right foot. There was also a loss of sensation in both legs.
An MRI was done and showed air trapped in the L45 epidural space. As the air slowly leaked out, the patient’s symptoms got better. Her pre-injection level of pain did not change.
This is the first case reported of air trapped in the epidural space causing worse neurologic symptoms after lumbar steroid injection. The authors suggest that many of the patients who have worse symptoms right after epidural injection may be suffering from this very same problem without knowing it.
Surgeons are advised to use less air or switch to nitrous oxide (NO) instead of air when injecting a steroid into the epidural space. Patients with chronic compression of the epidural space from bulging or herniated discs may be at risk for this problem. Scar tissue or adhesions may reduce the space available for the injection.