Fracture of S1-2 after L4-S1 decompression and fusion. Case report and review of the literature.

The author describes a woman in whom an S1-2 fracture developed after L4-S1 decompression and fusion. Osteoporosis was not present, but the lesion failed to respond to conservative therapy, necessitating surgical extension of the spinal fusion. Although biomechanical complications of lumbosacral fusion are uncommon, pseudarthrosis, degenerative spondylolisthesis, and stress fractures have been reported. To date, only four cases of sacral stress fracture appear in the literature, all involving female patients and reportedly associated with osteoporosis. Unlike the present case, the fracture resolved satisfactorily in all cases with conservative treatment.