Surgical Treatment of Gas-Containing Discal Cyst in the Lumbar Spine : Report of 2 Cases

We report our surgical experiences with two cases of gas-containing discal cyst. From January 2008 to December 2010, we have surgically treated 574 patients with spinal disorders, of which 309 were with lumbar degenerative disease. Out of 309 cases, 2 patients had gas-containing discal cyst. The first patient had multi-level spinal canal stenosis in the lumbar spine, and posterior decompression by the midline approach (splitting the spinous process) was carried out. A bubble-like cystic mass was removed at the L5-S1 level. The other patient had bilateral L5 isthmic spondylolysis, and a tubular retractor was used to remove the bubble-like cystic mass at the L5 level. Both patients resumed their daily activities within a few days after the operation. Histopathological studies of the excised cyst showed multi-cystic lesion surrounded by hyaline cartilage and fibrous tissue. The cyst contained mucosal material cartilage tissue. The latter reacted positive with S-100 protein, a hallmark for intervertebral disc. Since we did not perform intradiscal maneuver in these patients, the present gas-containing cysts are considered to be derived from intervertebral disc. Microsurgical removal of the cyst is recommended for satisfactory surgical results. Preoperative evaluation with computed tomography (CT) is mandatory for accurate diagnosis of the gas-containing discal cyst.