[Unusual differential diagnosis of posttraumatic back pain].

The differential diagnosis of lumbar back pain includes a broad spectrum of vertebral and extravertebral pathologies. Even in cases of a traumatic event physicians should keep an extravertebral cause in mind. This is a case report on the coincidence of perforated sigma diverticulitis and traumatic spine compression fracture in an 85-year-old woman with acute back pain. The presence of free retroperitoneal gas in the computed tomography (CT) scan was of significant diagnostic importance.