Cell based therapies as compared to autologous bone grafts for spinal arthrodesis

Study Design. Systematic review. Objective. To compare the clinical outcome of cell based grafts combined with bone extenders to autologous bone grafts. Summary of Background Data. Alternative graft options that combine mesenchymal stem cells (MSCs) and bone marrow aspirate (BMA) with synthetic or allograft scaffolds have been recently used in several animal and clinical studies. Methods. This systematic review of the literature addresses the following key questions (KQs): (1) Does the use of MSCs or BMA combined with synthetic or allograft extenders contribute to thoracolumbar fusion rates that are comparable with the rates achieved by the use of iliac crest graft? (2) Are these fusion rates comparable with those of local bone graft (LBG)? (3) Does the addition of MSCs or BMA to iliac crest bone graft or LBG contribute to better throracolumbar fusion rates? (4) Are the cervical spine fusion outcomes achieved by the use of SCM or BMA with synthetic or allograft scaffolds comparable with the iliac crest bone graft or LBG outcomes? (5) Was there any difference in terms of fusion rates, when MSCs were compared with BMA? Results. For KQ1, 4 level II, III studies used iliac crest bone graft as control. The results of these studies were inconsistent, and the overall body of evidence was found insufficient. Three, level II, III studies were identified for KQ2. Comparable fusion rates were demonstrated between LBG and BMA combined with calcium phosphate or collagen carrier. The overall body of evidence was found weak. For KQ3, one level III study was found. No significant difference was found in the fusion rates. No studies met the criteria for KQ4, 5. Conclusion. The currently available evidence is insufficient to support the use of MSCs or BMA combined with synthetic or allograft materials as a substitute or supplementary graft to autologous bone graft.