Epidural gas-containing pseudocyst leading to lumbar radiculopathy: A case report

BACKGROUND Lumbar radiculopathy is a common symptom in the clinic and is often caused by lumbar disc herniation or osteophytes compressing the nerve root; however, it is rare for nerve roots to be compressed by epidural gas. Few symptomatic epidural gas-containing pseudocyst cases have been reported. Furthermore, the reported cases were due to a mix of gas and obvious osteophytes; therefore, it was hard to rigorously conclude that gas was the factor responsible for radiculopathy. We provide evidence that because no epidural gas accumulated before radiculopathy occurred and the symptoms were relieved after removal of the gas, the epidural gas-containing pseudocyst was the root cause of radiculopathy in this case. CASE SUMMARY An 87-year-old man with a 3-wk history of right radiating pain was admitted to our hospital. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations showed a vacuum phenomenon and huge lesions with low signal intensity located in the same area where the pain occurred. After carefully checking the images acquired in the last 3 mo, we found an abdominal CT examination performed 40 d prior because of abdominal pain. The CT images showed no gas-containing pseudocyst in the epidural space and notably, he had no leg pain at the time. To ensure a low-intensity intervention and complete decompression of the nerve, percutaneous endoscopic lumbar nerve decompression surgery was advised. A gas-containing pseudocyst was identified under endoscopy. The symptoms were relieved after surgery, and the postoperative images showed total disappearance of the vacuum phenomenon and lesions with low signal intensity on CT and MRI. Histological examination showed that the sampled gas-containing pseudocyst tissue was fibrous connective tissue. CONCLUSION This case thoroughly illustrates that an epidural gas-containing pseudocyst can result in radiculopathic pain through a comprehensive evidence chain. Percutaneous endoscopic decompression is a minimally invasive and effective treatment method.