Fusion biologics and adjuvants in minimally invasive spine surgery

The utilization of minimally invasive spine fusion is increasing due to several benefits associated with it including shorter hospital stays, lower blood loss, and improved functional outcomes. The selection of a proper biologic based on its properties of osteoconductivity, osteoinductivity, and osteogenecity determines the success of spinal arthrodesis. Autologous bone graft, specifically iliac crest bone graft (ICBG), remains the historic gold standard due to its inherent osteoconductive, osteogenic, and osteoinductive nature without the risk of immunogenic reaction or disease transmission. However, there has been a significant interest in the development of bone graft substitutes and enhancers to relieve the shortcomings, including donor site morbidity, postoperative complications, and limited graft availability, of iliac crest bone graft. As a result, there has been an expansion of graft options such as allografts, demineralized bone matrix, ceramics, and growth factors. Bone morphogenetic proteins have been increasingly utilized in the last decade due to their efficacious osteoinductive properties. However, since their approval, the bone morphogenetic protein (BMP) use has been scrutinized due to its associations with a number of complications. There is an increased focus to alleviate these complications by lowering the dose of growth factor required through improved delivery and localization systems. Lastly, more data are required to establish the clinical efficacy of newer technologies such as cell and synthetic peptide-based therapy that may serve as viable options in the future.