Intradiscal gas can herniate to the epidural space, and herniated epidural gas may produce pseudocysts. We assessed the characteristics of and surgical treatments for lumbar epidural gas-containing pseudocysts as a cause of severe radicular pain.

We surgically treated epidural gas-containing pseudocysts in a total of 22 patients. We reviewed radiological parameters including the concomitant presence of vacuum discs, segmental instability, spinal stenosis, and location of pseudocysts. We retrospectively reviewed preoperative clinical parameters such as age, sex, clinical symptoms, neurologic deficits, and surgical methods.

We observed 25 levels of gas-containing pseudocysts in 22 patients. Twelve (48.0%) pseudocysts were in the canal, eight (32.0%) were in the foramen, and five (20.0%) were of extraforaminal type. All of the patients had degenerative vacuum discs in the affected levels. The incidence of neurologic deficits in patients with spinal stenosis was significantly higher than in patients without spinal stenosis (P<0.05).

We performed pseudocyst removal, neural decompression, and fusion surgery in 12 patients with symptomatic spinal stenosis or instability, and microscopic removal of pseudocysts in 10 patients without symptomatic spinal stenosis or instability.

We propose that lumbar gas-containing pseudocysts can produce radicular pain and/or neurologic symptoms, and that surgical removal of pseudocysts with or without optimal stabilization operations can significantly improve symptoms. The selection of surgical methods may depend on the presence of concomitant spinal stenosis or segmental instability.