Dorsal Epidural Gas after Lumbar Microdiskectomy Treated with CT-guided Needle Aspiration.

To present a case of unusual dorsal epidural gas (EG) accumulation after a simple lumbar microdiskectomy (MD), treated with computed tomography (CT)-guided needle aspiration. A 78-year-old woman underwent simple lumbar MD at the L3-4 level. One week after the operation, the patient complained of severe back pain radiating to the right thigh. Follow-up magnetic resonance imaging (MRI) and CT revealed huge EG formation at the dorsal L3-4 epidural space. Conservative treatment did not resolve the patient's pain. We performed CT-guided needle aspiration after 1 week of conservative treatment. The patient's pain fully resolved after aspiration, but it recurred 1 week later. Follow-up MRI and CT revealed re-accumulation of the dorsal EG at the L3-4 level. CT-guided needle aspiration was repeated, again leading to full pain resolution. Follow-up CT 6 months after the second aspiration showed no recurrent dorsal EG. The patient has been symptom-free for 1 year since the second aspiration. CT-guided needle aspiration is a safe and effective alternative to re-operation in the context of dorsal EG formation after MD.