Surgical fusion of the spine dates back to 1911, when the procedure was described by Albee [1], who provided mechanical support to vertebrae involved with tuberculosis, and by Hibbs [2], who treated the progression of scoliosis by spinal fusion. Since this time several techniques of fusion have been described and advocated with and without the use of instrumentation. Frequently the success of spinal surgery is dependent upon a solid fusion between selected intervertebral segments. The bony union which takes place is dependent upon several factors related to the host locally and systemically. Many of these factors have been elucidated, providing further information to enhance the rate of spinal fusion. However, there are certainly many facets of arthrodesis which are incompletely understood or not identified, for which further research is required. The rate of nonunion in the spine ranges from 5% to 35% [3, 4]; the improvement of these figures will be by the determination of the biology involved in achieving a successful fusion.