ENHANCEMENT OF BMP RETENTION
The use of autogenous bone graft is the current gold standard in the 1.5 million bone-grafting surgeries performed annually in the United States. Although this practice has resulted in high rates of fusion success, it is associated with increased operative time and blood loss, along with a significant degree of donor-site morbidity. Additionally, in certain settings such as revision cases, multilevel constructs, or in patients with medical co¬ morbidities, autogenous bone graft may exist in limited quantity and quality. This significant need for a suitable alternative to autogenous bone graft has stimulated great interest in the exploration of bone graft substitutes and extenders.