Tricolumnar osteotomy by posterior approach is a valuable tool. Rod failures found approximately 1 year from surgery, with 86% located at level of osteotomy and 14% at lumbosacral junction. Possible reasons are increased stress in the rod at this point and relatively deficient bone stock secondary to wide laminectomy. The low rate of rod breakage at lumbosacral junction may be related to adoption of structural interbody graft and stronger iliac screws. Additional biomechanical studies needed to assess the importance of these factors. This was a level IV study.