Pseudarthrosis and construct failure after lumbar pedicle subtraction osteotomy. Influence of biomechanics, surgical technique, biology and avoidance strategies

There are numerous factors that can lead to construct failure and pseudarthrosis after corrective pedicle subtraction osteotomy (PSO) in the lumbar spine. Frequently, several factors are of relevance in these problematic cases. This article attempts to explain the surgical, biomechanical and biological aspects that should be understood in order to minimize the risk of pseudarthrosis and construct failure. It addresses technical varieties of the PSO procedure as well as the surgical technique, the choice of rod material and the design of multirod constructs. Biological reasons for pseudarthrosis and preventive strategies are discussed, as well as the possible contribution of low-grade infections to pseudarthrosis. The option of substituting a multilevel ALIF procedure for a PSO is another topic, as is the question of surgical indication and strategy.