Comparison of 5-year outcomes between pedicle screw and hybrid constructs in adolescent idiopathic scoliosis

Abstract

Object Pedicle screw fixation has been theorized to provide better correction of scoliotic deformity, but controversy over the benefits of pedicle screw–only constructs remains, and the longer-term impact of pedicle screw fixation as compared with hybrid constructs is unclear. In this study, a retrospective review of a prospectively collected database was conducted to determine the longer-term impact of pedicle screw fixation as compared with hybrid constructs in patients with adolescent idiopathic scoliosis (AIS). Methods The authors retrospectively reviewed a multicenter database of pediatric patients (ages ≤ 18) from 1995 to 2006 and identified 127 patients with Lenke Type 1–4 AIS curves with a minimum 5 years of follow-up. Patients were divided into 2 cohorts based on whether they had undergone pedicle screw fixation or fixation with hybrid constructs. Results The mean main thoracic curvature of 56.1° ± 13.0°, which corrected to 14.9° ± 9.3°, translated into a mean correction of 73% (p < 0.01). The curve was 19.4° ± 10.6° at 2-year follow-up and 20.5° ± 10.4° at 5 years. When comparing preoperative parameters between the groups, differences were noted in the magnitude of the main thoracic curve (p = 0.04), flexibility of the main thoracic curve (p = 0.02), coronal balance (p = 0.04), T2–12 kyphosis (p = 0.02), and sex (p = 0.02). The pedicle screw cohort had fewer spinal segments instrumented (p < 0.01), fewer anterior releases performed (p = 0.02), and fewer thoracoplasties performed (p < 0.01). By 5 years of follow-up, significant differences were apparent between the two cohorts with respect to upper thoracic curvature (p = 0.01), T2–12 (p = 0.02) and T5–12 (p = 0.02) kyphosis, lumbar lordosis (p < 0.01), and sagittal balance (p = 0.01). Conclusions Although some preoperative differences did exist, outcomes were comparable between hybrid and screw constructs at 2 and 5 years. However, hybrid constructs required more concurrent anterior releases and thoracoplasties to achieve similar results.