Growth modulation and dynamic correction of early-onset thoracic scoliosis using a PEEK spring rib plate system: a porcine model study.

Abstract

To evaluate the growth modulation and corrective effects of a novel polyetheretherketone spring rib plate (PEEK-SRP) implant in a porcine model of early-onset thoracic scoliosis (EOS). 15 one-month-old pigs underwent thoracic nerve transection to induce right thoracic scoliosis. After 1.5 months of curve progression, animals were assigned to 3 groups: Untreated Group (UG, n = 6): Observed without intervention; Treated Group (TG, n = 6): PEEK-SRP implanted at three ribs on the convex apical levels; and Sham Group (SG, n = 3): Underwent the same surgical procedures as TG without the PEEK plate implantation. Radiographic and CT-based assessments were performed to evaluate Cobb angle, apical vertebral rotation (AVR), rib hump index (RHI), vertebra-rib angle difference (RVAD), thoracic volume, and spinal growth over 2.5 months. Baseline curves averaged 43.7 ± 9.4° with no group differences. At 2.5 months, the Cobb angle decreased by 17.5% (41.8° ± 11° to 34.5° ± 14.6°) in TG, compared with progression of 27.6% (54° ± 15.9° to 68.9° ± 16.8°) in UG (p = 0.0036) and 72% (35.4° ± 11.7° to 60.9° ± 5.9°) in SG (p = 0.0223). The PEEK-SRP reduced AVR by 87.3% (p < 0.0104), RHI by 79.4% (p < 0.0340), and improved RVAD by 15.2% (p < 0.0489) compared with controls. TG also demonstrated a 44% increase in convex thoracic area and an 86.8% increase in convex thoracic width compared to UG (p < 0.0005). Spine growth rate (9.6 ± 2.4 mm/week in UG, 12.7 ± 4.6 mm/week in TG, and 9.4 ± 0.4 mm/week in SG) was not different among the three groups (p = 0.1844). The PEEK-SRP system provided effective apical control, rib cage remodeling, and spinal correction while preserving thoracic growth in a porcine EOS model. This transverse load-sharing, non-fusion strategy directly targets rib-spine deformity and shows promise as a growth-friendly treatment for EOS. 1. The PEEK-SRP system offers a novel, non-fusion strategy for treating early-onset thoracic scoliosis by targeting rib cage deformities at the curve apex. 2. Unlike traditional growing rods, which are longitudinal load-bearing devices with high complication rates and no apical control, the PEEK-SRP system functions as a transverse load-sharing implant that directly modulates rib-spine growth. 3. In a porcine EOS model, PEEK-SRP implantation significantly reduced spinal curvature, apical vertebral rotation, and rib hump deformity, while increasing thoracic volume. 4. The implant preserved spinal growth and flexibility, confirming its role as a growth-friendly corrective system. 5. This study supports the clinical potential of PEEK-SRP for children with moderate progressive scoliosis, offering segmental correction without compromising thoracic development.