Origami-Inspired Deployable Fixation and Scaffold System Optimized by Machine Learning for Pediatric Distraction Osteogenesis

Distraction osteogenesis (DO) is a widely accepted surgical technique used to regenerate bone by gradually separating two segments of a previously osteotomized bone. It leverages the body’s natural capacity for bone formation and is commonly used to correct congenital limb deformities, post-traumatic defects, and skeletal length discrepancies. While the procedure is highly effective, its clinical application—particularly in pediatric patients—remains constrained by anatomical and biological limitations. DO treatment involves prolonged consolidation times, patient discomfort from external fixators, and, in the case of growing individuals, the risk of damage to open growth plates. Additionally, existing regenerative strategies, including scaffold-based augmentation, fail to accommodate the evolving mechanical and geometrical environment imposed by progressive distraction. Despite its success, the standard DO protocol involves immobilization using external fixators for several months, posing discomfort, high infection risk, and significant psychosocial burdens for pediatric patients. Intramedullary lengthening nails, though more discrete, are generally not recommended in skeletally immature individuals due to the risk of injury to epiphyseal growth plates. For children requiring DO, a critical unmet need exists: a fixation system that is internal, load-bearing, and compatible with bone growth. Moreover, the mechanical environment of DO presents challenges for scaffold-based approaches. As the osteotomy gap increases from a few millimeters to several centimeters over the course of treatment, conventional scaffolds—typically designed for static defects—are unable to adapt to this dynamic geometry. Mechanical failure, loss of porosity, or inability to accommodate strain often compromise biological effectiveness of scaffolds. Clinically, this results in prolonged healing times and inconsistent bone quality, despite advances in scaffold biofabrication.