Graft Options in Posterolateral and Posterior Interbody Lumbar Fusion

Study Design. Review article, review of literature. Objective. To review the bone graft options that exist for posterolateral and posterior interbody lumbar fusion. Summary of Background Data. As the number of lumbar fusion surgeries has increased over the last decade, alternative methods of grafting have been developed. Iliac crest autograft bone has traditionally been used for lumbar fusion. The downside to this graft option, however, is donor site morbidity. Methods. The current literature on alternatives to iliac crest autograft bone for obtaining lumbar fusion was reviewed. Results. Platelet gels, demineralized bone matrix, synthetic bone graft, and bone morphogenetic protein are potential options for bone graft supplementation or substitution. In preclinical studies, platelet gels have been beneficial to bone growth when combined with autograft, but clinical studies do not support the use of platelet gel in posterolateral lumbar fusion. Preclinical studies of demineralized bone matrix have shown significant variability in the osteoinductive properties of the available products, and clinical data showing efficacy is limited. The use of synthetic bone graft material (ceramics) in lumbar fusion surgery is increasing. Calcium phosphate compounds (i.e., &bgr;-tricalcium phosphate and hydroxyapetite) are most commonly used and are often combined with type I collagen to form a matrix. These materials provide an osteoconductive scaffold for bony ingrowth and can be combined with bone marrow aspirate or used as a carrier for osteogenic factors. Bone morphogenetic protein (rhBMP-2) has been shown to provide similar or even increased fusion rates over autograft iliac crest bone. There are, however, potential safety concerns associated with the use of bone morphogenetic protein that are not fully understood. Conclusion. Several alternatives to iliac crest autograft bone provide promising early clinical results in achieving posterolateral and posterior interbody lumbar fusion.