Extracranial epidural emphysema: pathway, aetiology, diagnosis and management.

Extracranial epidural emphysema is an uncommon phenomenon that refers to the presence of gas within the epidural space. As an isolated finding, it is typically benign, but it can be a secondary sign of more ominous disease processes, such as pneumothorax, pneumoperitoneum and epidural abscess. Although the phenomenon has been cited in case reports, a comprehensive review of this topic is lacking in the radiology literature. The authors' aim is to report our experience with extracranial epidural emphysema, illustrating the spectrum of its clinical presentation. We also review the aetiology, pathophysiology, diagnosis and management of extracranial epidural emphysema.