Surgical images: musculoskeletal. Delayed cauda equina syndrome due to a sacral insufficiency fracture missed after a minor trauma.

a 54-year-old woman was examined at the emergency department and discharged. Her evaluation included radiographs observed to be normal except for an isolated pubic ramus fracture. Over the ensuing 2 weeks she became bedridden with pain and increasing numbness in her feet, and was readmitted to hospital. Her strength was preserved, but she had numbness in the posterior legs and her soles, saddle anesthesia and an absence of rectal tone, and had become incontinent (both stool and urine). Clinical examination of this cachectic woman found ecchymosis and tenderness over the sacral spine. Upon admission, the right pubic ramus fracture was observable on an anteroposterior x-ray of her pelvis, along with significant osteopenia (Fig. 1). The lateral lumbosacral x-ray taken just after her initial fall showed acute kyphosis and anterolisthesis of S1 over S2 (Fig. 2), which had been missed by the initial trauma team. Other conclusions from the plain films were difficult because of patterns left by overlying bowel gas; a CT scan, however, exhibited a Ushaped fracture pattern around the body of S1 (Fig. 3). MRI further characterized the injury, demonstrating an epidural collection consistent with hematoma located posterior to the S1 body as well as anterolisthesis of S1 over S2 and acute kyphosis at this level (Fig. 4). The patient underwent urgent posterior decompression with sacral laminectomies from S1 to S3. Both S2 nerve roots were found to be entrapped in the fracture line and were freed. In addition, open reduction and internal fixation with bilateral sacroiliac screws at S1 and S2 were performed. The patient became progressively steadier on her feet and within 2 months regained partial sensation in her legs and full voluntary bladder and rectal control. Review of the patient’s history revealed intestinal malabsorption as a cause for her severe malnourishment and consequent osteoporosis. The