Title: Improving Spinal Growth Modulation using a Novel Kyphotic Porcine Model PROJECT SUMMARY Spinal fusion is the current standard of care for the treatment of pediatric spinal deformities. However, this technique ignores the child’s growth potential and eliminates all growth and motion through the deformed regions of the spine. Recently, attempts to harness the growth potential of the immature spine using flexible vertebral tethers to correct spinal curvatures have been promising; however, the effectiveness of these techniques appears limited to small deformities in younger patients. In this work, we propose to use a novel kyphotic porcine model to (1) determine if straight and deformed spines respond differently to tether tension, (2) measure the effects that different tether tensions have on growth in the deformed spine, and (3) compare the rates of deformity correction using tethers with and without vertebral periosteal resection. While current spinal growth modulation strategies have relied on deformity correction through convex growth inhibition alone, we will combine growth acceleration in the concavity with convex growth inhibition, to increase the magnitude of deformity correction possible using these non-fusion techniques. At the conclusion of this study, the differences in the effects that varying tether tensions have on normal and deformed spines in terms of disc behavior and longitudinal vertebral growth rates will be determined. We anticipate that increasing tether tension will cause an immediate change in vertebral alignment but will inadvertently inhibit the differential growth necessary for long lasting deformity correction. Conversely, we expect periosteal resection to accelerate overall vertebral growth and therefore increase the effectiveness of the standard tethering. As this work will be performed in our novel large animal model, these data can be readily translated to improve current clinical spinal growth modulation strategies and make this model a platform on which to develop and refine new growth modulating devices.