Shoichi Wada

Symptomatic epidural gas cyst associated with discal vacuum phenomenon.

Study Design. Four cases of computed tomography and magnetic resonance imaging documented lumbar nerve root compression associated with a vacuum disc communicating with the epidural space are presented. Objective. To give an insight into the mechanism of nerve root compression associated with vacuum disc phenomenon. Summary of Background Data. Few cases of lumbar radiculopathy resulting from epidural gas have been reported and illustrated using cross-sectional imaging studies. Methods. The medical records, imaging examinations, and surgical findings (when available) of 4 symptomatic patients with epidural and intradiscal gas collections were reviewed. Three patients underwent surgery with needle aspiration of the epidural gas, and 1 patient was treated conservatively. Results. Clinical symptoms of epidural gas cyst were similar to those of other more common causes of nerve root compression. Computed tomography and magnetic resonance imaging findings showed intraspinal gas collection associated with a vacuum disc. One patient had an additional vertebral pneumatocyst. Although evacuation of intraspinal gas resulted in complete cure or major neurologic improvement in 3 patients, an initial period of observation is warranted because gas may disappear spontaneously as in 1 of our patients. All 4 patients recovered full motor and sensory functions of the lower extremities. One year later, patients were completely free of symptoms. Conclusion. Although the vacuum disc is considered a common imaging finding of no or not much pathologic significance, occasionally intradiscal gas may leak into the spinal canal. Detection of an epidural gaseous collection at the same level with a vacuum disc strongly suggests a communication between the intervertebral disc and the epidural space. Epidural gas collections can be implicated as a possible cause of radicular symptoms and should be considered in the differential diagnosis of lumbar radiculopathy.