Stem Cells in Spinal Fusion

Study Design: Review of literature. Objectives: This review of literature investigates the application of mesenchymal stem cells (MSCs) in spinal fusion, highlights potential uses in the development of bone grafts, and discusses limitations based on both preclinical and clinical models. Methods: A review of literature was conducted looking at current studies using stem cells for augmentation of spinal fusion in both animal and human models. Results: Eleven preclinical studies were found that used various animal models. Average fusion rates across studies were 59.8% for autograft and 73.7% for stem cell–based grafts. Outcomes included manual palpation and stressing of the fusion, radiography, micro–computed tomography (μCT), and histological analysis. Fifteen clinical studies, 7 prospective and 8 retrospective, were found. Fusion rates ranged from 60% to 100%, averaging 87.1% in experimental groups and 87.2% in autograft control groups. Conclusions: It appears that there is minimal clinical difference between commercially available stem cells and bone marrow aspirates indicating that MSCs may be a good choice in a patient with poor marrow quality. Overcoming morbidity and limitations of autograft for spinal fusion, remains a significant problem for spinal surgeons and further studies are needed to determine the efficacy of stem cells in augmenting spinal fusion.