Sacral fractures after multi-segmental lumbosacral fusion: a series of four cases and systematic review of literature.

Spine surgeons are becoming increasingly aware of sacral insufficiency fractures as a complication after lumbosacral fusions. We present four patients who suffered from sacral fractures after multi-segmental posterior lumbosacral fusion together with a systematic review of the literature that yielded six papers reporting on 12 cases. Summarizing these 16 cases, the typical patient suffering from this complication is a female, elderly individual [66.4 +/- 12.3 (mean +/- SD) years of age, 95% confidence interval 57.89-71] undergoing multilevel fusion of 4.9 +/- 3.4 (95% CI 3.1-6.8) segments. Due to nonspecific clinical complaints and inconclusive imaging there has been a median delay in diagnosis of 5 (IQR 3-6, range 1-49) weeks after onset of pain. It remains unclear whether this complication is rare or rather under-diagnosed. Fortunately, these fractures are predominantly benign conditions that respond well to conservative management in the majority of cases, depending on location.