Carrier materials for spinal fusion.

BACKGROUND CONTEXT: The rise in spinal fusion procedures has led to an increase in the available number and variety of bone graft substitutes. As our understanding of the biologic processes that influence bony fusion has improved, appreciation for the role of the carrier material involved in bone grafts has also increased.
PURPOSE: The abundance of products available leaves a surgeon with many choices. Knowledge of the current advances will allow for more critical review of the literature and improved decision making when choosing bone graft materials. STUDY DESIGN/
SETTING: Review of the English-language literature.
METHODS: A critical review of basic science, animal and human studies that investigate the types and role of carrier materials used in spine surgery.
RESULTS: The myriad of carrier material available to the spine surgeon is related to the many options in bone graft material. Allograft is an important osteoconductive agent but has its disadvantages especially in regard to disease transmission and immunogenicity. Collagen in various forms is an effective carrier for bone morphogenic protein and autogenous stem cells and can be easily combined with other bone graft materials. Synthetic options include hydroxyapatite and calcium phosphate ceramic materials with different formulations; all are osteoconductive only but can be combined with osteoinductive and/or osteogenic components. Bioabsorbable carriers are effective for use with bone morphogenic protein and can also be used in multiple forms and settings.
CONCLUSIONS: Many bone graft carriers exist, and multiple studies have shown their efficacy. It appears that no one carrier is ideal but each situation might influence the choice of one carrier over another.