Cauda Equina Syndrome Caused by Epidural Pneumorrhachis

Abstract

A case report and review of the literature. To present a rare case, and its treatment, of cauda equina syndrome (CES) caused by epidural pneumorrhachis after repeated caudal epidural injections. Pneumorrhachis is defined as the presence of air in the epidural or subarachnoid space. Epidural pneumorrhachis is usually asymptomatic and managed conservatively, but rare cases of lumbar radiculopathy resulting from epidural air have been reported. To the best of our knowledge, there has been no previous report of CES caused by epidural air. A 63-year-old male presented with recent aggravation of a low backache, with pain radiating to both lower limbs. He also complained of newly developed numbness in the buttocks, groins, and perineum, and difficulty with urination and defecation, after repeated caudal epidural injections during a 3-week period. Computed tomography and magnetic resonance imaging revealed epidural pneumorrhachis compressing the lumbar dural sac at the L2-L3 and L3-L4 levels. The patient's symptoms persisted despite 3 days of oxygen inhalation therapy. Attempted needle aspiration of the epidural air was unsuccessful and percutaneous computed tomography-guided translaminar trephination was performed. The day after trephination, the patient's lower extremity motor strength began to improve; sphincter dysfunction began to resolve on the second day. During 8 weeks, his pain resolved and he gradually regained sensation. Two years later, the patient was free of symptoms or signs of CES. Epidural pneumorrhachis may cause dural sac compression, thus worsening a patient's previous symptoms and possibly eliciting new problems such as CES. Conservative treatment should be the first-line approach, but surgery is often necessary when the problem remains unsolved. Percutaneous computed tomography-guided translaminar trephination may be an alternative to surgical decompression of the epidural space in selected patients.