Pedicle screw fixation strategies of the thoracic curve in adolescent idiopathic scoliosis

Abstract

Summary: The study addressed the radiographic, clinical and cost-analysis of three pedicle screw strategy techniques for the treatment of AIS. The study noted that pedicle screw strategy techniques utilizing non-contiguous multilevel screw fixation (CMSS) maintain an FBCI greater than 100%, are cost-effective, and provide similar clinical outcomes as CMSS. Introduction: Studies have demonstrated that taking into account curve flexibility based on the fulcrum bending radiograph in patients with adolescent idiopathic scoliosis (AIS) is imperative to best assess curve correction following surgery. We present the prospective radiographic, clinical, and cost comparisons of three pedicle screw fixation strategies in the treatment of thoracic AIS while accounting for curve flexibility. Methods: Ninety-four AIS patients were prospectively assessed. Seventeen patients had key-vertebral screw strategy (KVSS), 42 had alternate level screw strategy (ALSS), and 35 received contiguous multilevel screw strategy (CMSS). Titanium rods were utilized in the KVSS and ALSS cases, whereas stainless-steel rods were applied in patients with CMSS. Pre- and postoperative postero-anterior and fulcrum bending radiographic Cobb angles were obtained. The fulcrum flexibility and the fulcrum bending correction index (FBCI) were assessed. Final follow-up SRS-22 Questionnaire were assessed. Instrumentation cost analyses was conducted of all three strategies. Results: The FBCIs of the KVSS, ALSS, and the CMSS were 119%, 122%, and 152%, respectively (p<0.001). There was no statistically significant difference between the overall SRS-22 scores and strategy techniques (p>0.05). In comparison to the CMSS, the KVSS and ALSS were associated with pedicle screw cost reductions of 41.7-73.1% and 33.3-46.2%, respectively. Conclusion: Although the CMSS may provide an increased amount of FBCI, the KVSS and ALSS utilizing less pedicle screws for the surgical treatment of AIS are safe, cost-effective, and achieve an FBCI greater than 100% in the majority of cases while achieving similar clinical outcomes. In AIS patients with flexible thoracic curves, the KVSS and ALSS are viable alternatives to CMSS. In addition, one should remain cognizant that variation in instrumentation (e.g. stainless steel rods vs. titanium rods) may affect the degree of FBCI. Significance: In comparison to the CMSS, ALSS and KVSS utilize less pedicle screws while maintaining an FBCI greater than 100%, are cost-effective, and provide similar clinical outcomes. In particular, in AIS patients with flexible thoracic curves, the KVSS and ALSS are viable alternatives to CMSS.