Pseudarthrosis and techniques for fixation to the pelvis

For adult patients undergoing spinal deformity correction surgery, it is unclear if fusion should routinely end at L5 or S1. Adding to this controversy is the concern for the development of a pseudarthrosis at L5-S1 with attempted fusions caudal to long constructs, which remains a challenging problem. There are a number of different constructs that have been used to stabilize the lumbosacral junction. Pelvic fixation into the ilium, whether by iliac screws or alar-iliac screws, provides rigid lumbosacral fixation that generally results in the lowest pseudarthrosis rates with adult deformity constructs. The addition of L5-S1 interbody fusion, either TLIF or ALIF, should be considered requisite if the most distal fixation points are S1 or S2 screws. Newer techniques, such as transsacral axial interbody fusion, may offer an alternative to open L5-S1 interbody fusion, though data are limited to case series. Perhaps most important is for deformity surgeons to consider, in concert, spinal alignment parameters, host biology, and adequate surgical fixation in order to minimize the likelihood of lumbosacral pseudarthrosis.