New developments and insights learned from distraction osteogenesis

Purpose of review: Distraction osteogenesis (DO) techniques have been developed and practiced in orthopaedics and craniofacial surgery with outstanding clinical outcomes. This review discusses recent advances in understanding the basic biologic mechanisms of DO, new methods of assessing and promoting bone consolidation in DO, and new clinical applications of DO. Recent findings: Many genes are upregulated or downregulated in bone cells responding to mechanical stimulation. The changing patterns of BMPs expression and apoptosis may regulate bone regeneration in DO. High magnitude strain promotes bone remodeling, whereas low magnitude stain stimulates osteogenesis. DO not only increases local angiogenesis, but also leads to increased expressions of VEGF and its receptors systemically. Routine radiography remains the most cost-effective imaging technique to follow all aspects of the regenerate, followed by ultrasound, mechanical testing, DEXA and QCT. Minimal noninvasive means of intervention for promoting bone consolidation are preferable, such as weight-bearing exercise, ultrasound, and electromagnetic stimulation; whereas systemic administration of anabolic agents and hormones may also be useful and local application of growth factors such as BMPs remains the last resort. New applications of DO have been extended into treating craniofacial deformities and vascular diseases, but more basic and clinical researches are needed. Summary: Distraction osteogenesis techniques have a wider implication in understanding the human body’s self-repair and self-regeneration potentials and its new clinical applications are to be extended to functional tissue engineering, management of soft-tissue repair, and treatment of vascular diseases and others.