Comparative study of low-density versus high-density pedicular screw implantations in management of adolescent idiopathic scoliosis: a randomized clinical trial

A number of studies have yielded disparate findings regarding the relationship between implant density and curve correction in adolescent idiopathic scoliosis (AIS) surgery. This study compared the efficacy and safety of low-density (LD) versus high-density (HD) pedicular screw implants in the correction of deformity in AIS regarding clinical, radiological, and quality of life outcomes. This study was a single-blind, parallel, randomized trial that enrolled 20 adolescent patients with idiopathic scoliosis scheduled for posterior spinal fusion surgery with all pedicle screw constructs. Patients were randomized into two groups of 10 patients each. The LD group included patients in whom the number of screws per fused spinal level had a density of 1.5 or less, while the HD group had a density greater than 1.5. The primary outcomes were the radiological findings of curve correction. The secondary outcomes included the correlation between implant density and curve correction, the amount of blood loss, operation time, number of screws, fusion level, hospital stay duration, and quality of life assessed by the Scoliosis Research Society 22r questionnaire. Radiologically, the postoperative main curves Cobb angles and their changes were comparable between both approaches without statistical correlation with the implant density (p˃0.05). The LD approach significantly shortened the operative time (p=0.015), number of screws (p=0.011), implant density (p<0.001), and hospital stay (p<0.001). However, quality of life scores before surgery and at final follow-up did not differ between the two techniques (p˃0.05). The use of a low-density approach is an effective and safe methodology for attaining satisfactory deformity correction in AIS patients. Furthermore, this approach confers the additional advantage of reduced operative time, number of screws, implant density, and hospital stay in comparison to the high-density approach. Trial registration Pan African Clinical Trial Registry, PACTR202404611444119. Registered 28 March 2024-Retrospectively registered, https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=29382