Gas-containing disc herniations: dual nerve root compression at a single disc level.

A 72-year-old man presented with gas-containing disc herniations resulting in dual nerve root (exiting and traversing root) compression at the single level manifesting as lower back pain with the right anterolateral thigh and medial calf pain and no response to 4 weeks of conservative treatment. Physical examination revealed positive Lasegue's sign at 40°, but the patient had no evidence of neurological deficit. Magnetic resonance imaging showed two separate disc herniations, a posterocentral herniated disc that had migrated inferiorly at the L3-4 level and compressed the L4 traversing root, and another that had compressed the L3 exiting root in the extraforaminal area at the same level. Coronal computed tomography demonstrated the presence of gas in the spinal canal and extraforaminal area at the L3-4 level, and the vacuum phenomenon was also noted at the L3-4 intervertebral disc. Microscopic discectomy was performed using midline and paramedian approaches, and the presence of gas was confirmed by bubbles after pouring saline into the area intraoperatively. Histological examination revealed fibrous tissue. The patient was discharged with complete relief of pain. This is a rare case of symptomatic gas-containing disc herniations causing dual compression of exiting and traversing roots at a single disc level.