Spine fusion: cages, plates and bone substitutes. Biomaterials for spinal surgery

Abstract: Spine fusion is the surgical procedure to obtain bony union between two vertebrae, required in the treatment of many pathologies. The necessity for this procedure is increasing, and complications such as non-union remain high in spite of the great progress that has been made in recent years. Many surgical techniques have improved the effectiveness of this procedure in the past, involving very sophisticated techniques. Bone substitutes may enhance bone healing, though many are not especially effective. Bone grafts still remain the best option, but many concerns are raised about their safety, stockage, availability and properties. Synthetic bone substitutes were proposed as a resolution to this problem, but none of them have achieved the ideal standard. Growth factors are the ‘new’ expected ideal bone substitutes, but little is known about their function, and results are contradictory, except for BMP-2 and BMP-7 in spine fusion. This chapter will discuss these problems and evaluate the options and the advantages and disadvantages of bone substitutes that are available in spine fusion.