Outcomes of Pelvic Fixation in Growing Rod Constructs: An Analysis of Patients with a Minimum of 4 Years of Follow-up

Study Design Retrospective review. Objective To evaluate which distal anchors in growing rod (GR) constructs optimally correct major curve, pelvic obliquity, sagittal alignment, T1-S1 length, thoracic kyphosis, and lumbar lordosis with the fewest complications at 4 or more years' postoperative follow-up. Summary of Background Data Pelvic fixation to the ilium and/or sacrum in GR constructs is used to treat patients with early-onset scoliosis. No studies have evaluated radiographical outcomes and complications in these patients at 4 or more years' follow-up. Methods Included were 38 patients from a multicenter early-onset-scoliosis database with dual GRs anchored to the pelvis. Radiographic data included major curve, T1-S1 length, T5-T12 kyphosis, lordosis, sagittal alignment, and pelvic obliquity at preoperative and latest follow-up time points. Complications were evaluated for all anchor subtypes. Results Mean follow-up time was 5.3 ± 0.1 years. GRs with distal anchors to the ilium significantly improved major curve (49%, p =.013) and pelvic obliquity (78%, p =.035) compared with constructs anchored to the sacrum only. Constructs with iliac fixation with S1 screws provided greater correction of lumbar kyphosis than constructs with iliac fixation and no S1 screws (p =.023). Constructs with a single caudal crosslink had a greater T1-S1 length at latest follow-up than constructs with combined cephalad and caudal crosslinks (p =.027). There were no significant differences in the rates of infection or instrumentation failure between iliac and sacral fixation groups. GR constructs with distal anchors that used a posterior superior iliac spine start point had a higher infection rate (60%) than those inserted via a sacral-alar-iliac technique (7%) (p =.002). Conclusions GR constructs anchored to the ilium provide significant improvements in the major curve and pelvic obliquity at a minimum of 4 years of follow-up versus constructs anchored to the sacrum alone. Level of Evidence Level III, retrospective cohort study.