Intradural disc herniation and epidural gas: something more than a casual association?

STUDY DESIGN: The case of a patient with an intradural disc herniation associated with gas in the spinal canal is presented.

OBJECTIVE: To alert spine surgeons to this potential association.

SUMMARY OF BACKGROUND DATA: This association was described previously in five patients, a fact that seems surprising given the relative rarity of both intraspinal gas and intradural herniations.

METHODS: The case is presented of a female patient with lumbosciatic pain who developed an incomplete cauda equina syndrome. An asymmetric discopathy of the L2-L3 space and a gas bubble with disc material within the spinal canal was noticed in the radiologic explorations. The literature and the authors' experience are reviewed with the aim of confirming the frequency of intradural herniation in association with gas in the spinal canal.

RESULTS: A laminoarthrectomy of the involved space was performed followed by direct intradural examination, which revealed a disc fragment that was excised. An instrumented L2-L3 arthrodesis was performed. Postoperative evolution was satisfactory. To date, the authors have found this association in 2% of the patients with intraspinal gas.

CONCLUSION: The potential presence of an intradural disc herniation must always be considered when performing an open discectomy on a patient whose CT scan study shows the presence of epidural gas. This association is particularly striking given the relative rarity of intradural herniations and intraspinal gas. In the event that no clear disc herniation was found, an intradural examination may be indicated to justify clinical signs and symptoms or previous radiologic studies.