New growth rod concept provides three dimensional correction, spinal growth, and preserved pulmonary function in early-onset scoliosis

Introduction This study aims to describe a novel minimal invasive early-onset scoliosis (EOS) growth rod concept, the Cody Bunger (CB) Concept, which combines concave interval distraction and contralateral-guided growth with apical control and to investigate the 3D deformity correction, the spinal growth, and the pulmonary development. Method A series of 38 children with progressive EOS and growth potential, receiving a highly specialized surgical treatment, including primary and conversion cases. Mean age was 10.2 years (4.4-15.8) with a mean follow-up of 5.6 years, and they underwent 168/184 open/magnetic lengthening procedures. Outcomes were as follows: scoliosis, kyphosis, and lordosis angles; apical rotation; spinal length; apical translation; coronal and sagittal vertical alignment; complications; and pulmonary function in a subgroup. Results Scoliosis improved from mean 76 degrees (46-129) to 35 degrees (8-74) post-op and was 42 degrees (13-83) at end of treatment. Apical rotation was reduced by 30% but was partially lost during treatment. Thoracic kyphosis initially decreased by mean 15 degrees and was partially lost during treatment. Lordosis was largely unaltered during treatment. Mean T1-S1 height increased from 30.7 cm (22.7-39.2) to 34.6 cm (27.8-45.1) postop and further increased to 38.5 cm (30.1-48.1) during treatment. This corresponded to a T1-S1 growth rate of 12 mm/year, and positive growth rates were found in all height parameters evaluated. Frontal balance and apical translation improved, whereas sagittal balance was unaltered. Complications occurred in 22/38 patients, and 11/38 had an unintended reoperation. Pulmonary function (FVC and FEV) increased but the relative lung function was unchanged. Conclusion The new growth rod concept provided 3D correction and spinal growth at complication rates comparable with other growth-friendly techniques for EOS, while pulmonary function was preserved. Single magnetic rod distraction was incorporated successfully, replacing surgical elongations.