Sacral insufficiency fractures.

PURPOSE: To highlight difficulties in the diagnostic process and the validity of imaging techniques for sacral insufficiency fractures.

METHODS

Records of 25 women aged 68 to 95 years with sacral insufficiency fractures were reviewed. Baseline blood biochemistry and haematology test results were obtained. Pelvic anterior/posterior radiography was undertaken for all patients; additional computed tomography, technetium bone scanning, and magnetic resonance imaging were used in some. Treatments were based on the severity of the injury and the patient's mobility and cooperativeness.

RESULTS

Among the 25 women, 11 had bilateral and 14 had unilateral vertical sacral fractures. Associated fractures included horizontal sacral fracture, fractures of the os pubis and ilium. Symptoms included lower back or buttock pain, abdominal pain, and those emulating radiculopathy and myelopathy, including leg weakness, sciatica, and urinary retention. The mean delay in diagnosis was 9 (range, 1-28) days. The mean recovery time between bilateral and unilateral fractures was significantly different (22 [range, 12-33] vs 14 [range, 8-36] weeks, p=0.01). No patient with bilateral fractures regained her pre-injury mobility, compared to 43% among those with unilateral fractures (p=0.02, Fisher's exact test). Computed tomography was the most reliable imaging technique; technetium bone scanning was highly sensitive but non-specific; magnetic resonance images of the fractures may mimic metastatic disease.

CONCLUSION

With the increase in the elderly population, sacral insufficiency fractures may become epidemic in future. Primary and secondary osteoporoses are common causes. Once a diagnosis is established, in most cases treatment is simple but recovery may be protracted and full mobility curtailed.