BACKGROUND: Rapid, reliable fusion is the goal in anterior cervical diskectomy and fusion. Iliac crest autograft has a high rate of donor-site morbidity. Alternatives such as bone graft substitutes lack osteoinductivity, and recombinant bone morphogenetic proteins risk life-threatening complications. Both allogeneic mesenchymal precursor cells (MPCs) and amnion derived epithelial cells (AECs) have osteogenic potential.
OBJECTIVE: To compare for the first time the capacity of MPCs and AECs to promote osteogenesis in an ovine model.
METHODS: Five groups of 2-year-old ewes were subjected to C3-4 anterior cervical diskectomy and fusion with a Fidji interbody cage packed with iliac crest autograft alone (group A; n = 6), hydroxyapatite-tricalcium phosphate Mastergraft granules (HA/TCP) alone (group B; n = 6), HA/TCP containing 5 million MPCs (group C; n = 6), or HA/TCP containing 5 million AECs (group D; n = 5); group E was made up of age-matched nonoperative controls (n = 6). At 3 months, animals were euthanized and quantitative multislice computed tomography, functional radiography, biomechanics, histology, and histomorphometry were performed.
RESULTS: No procedure- or cell-related adverse events were observed. There was significantly more fusion in the MPC group (C) than in group A, B, or D. Computed tomography scan at 3 months revealed that 5 of 6 MPC-treated animals (83%) had continuous bony bridging compared with 0 of 5 AEC-treated and only 1 of 6 autograft- and 2 of 6 HA/TCP-treated animals (P = .01).
CONCLUSION: Implantation of allogeneic MPCs in combination with HA/TCP within an interbody spacer facilitates interbody fusion after diskectomy. The earlier, more robust fusion observed with MPCs relative to autograft and HA/TCP bone substitute indicates that this approach may offer a therapeutic benefit.
*Monash Immunology and Stem Cell Laboratories, Melbourne, Victoria, Australia; ‡Department of Surgery, Monash University, Melbourne, Victoria, Australia; §Mesoblast Ltd, Melbourne, Victoria, Australia; ¶Department of Neurosurgery, Monash Medical Centre, Clayton, Victoria Australia; ‖Department of Neurosurgery, The Alfred Hospital, Prahran, Victoria, Australia; #Centre for Cancer Biology, Institute of Medical and Veterinary Science/SA Pathology and Robinson Institute, University of Adelaide, South Australia, Australia; **Institute of Bone and Joint Research, Royal North Shore Hospital, St Leonards, New South Wales, Australia; ‡‡Gribbles Pathology Pty Ltd, Clayton, Victoria, Australia; §§Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
Received, February 20, 2010.
Accepted, June 10, 2010.
Correspondence: Dr Tony Goldschlager, MBBS, PhD, Department of Neurosurgery, Monash Medical Centre, 246 Clayton Rd, Clayton, Victoria 3168, Australia. E-mail: firstname.lastname@example.org