Fusion performance of low-dose recombinant human bone morphogenetic protein 2 and bone marrow-derived multipotent stromal cells in biodegradable scaffolds: A comparative study in a large animal model of anterior lumbar interbody fusion
Abbah, S.A. Lam, C.X.F. Ramruttun, A.K. Goh, J.C.H. Wong, H.-K.
Abbah, S.A.
Ramruttun, A.K.
Wong, H.-K.
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Abstract
Study Design.: A large animal study comparing interbody fusion of a bioresorbable scaffold loaded with either low-dose recombinant human bone morphogenetic protein 2 (rhBMP-2) or bone marrow-derived multipotent stromal cells (BMSCs). Objective.: To compare the quality of fusion resulting from implantation of medical grade poly (ε-caprolactone)-20% tricalcium phosphate (mPCL/TCP) scaffolds and two different bone growth stimulating agents. Summary of Background Data.: Nondegradable cages have been used for interbody fusion with good results. However, the overall advantage of lifelong implantation of a nondegradable device remains a subject of ongoing debate. The use of bioresorbable scaffolds might offer superior alternatives. In this study, we evaluated the quality of fusion obtained with two potential bone graft substitutes. Methods.: Eleven Yorkshire pigs underwent a bisegmental (L2/L3; L4/L5) anterior lumbar interbody fusion (ALIF) in four groups, namely: (1) mPCL/TCP + 0.6mg rhBMP-2; (2) mPCL/TCP + BMSCs; (3) mPCL/TCP (negative control); and (4) autologous bone grafts (positive control). Results.: The mean radiographic scores at 9 months were 3.0, 1.7, 1.0, and 1.8 for groups 1 to 4, respectively. The bone volume fraction of group 1 was two-folds higher than group 2. Histology, micro-computed tomographic scanning and biomechanical evaluation demonstrated solid and comparable fusion between groups 1 and 4. However, group 2 showed inferior quality of fusion when compared with groups 1 and 4 while group 3 showed no fusion even at 9 months. In addition, there was no evidence of implant rejection, chronic inflammation or any other complications. Conclusion.: mPCL/TCP scaffolds loaded with low-dose rhBMP-2 is comparable to autograft bone as a bone graft substitute in this large animal ALIF model. Although BMSCs lagged behind autograft bone and rhBMP-2, evidence of bone ingrowth in this group warrants further investigation. Our results suggest that mPCL/TCP scaffolds loaded with rhBMP-2 or BMSCs may be a viable alternative to conventional cages and autograft bone. © 2011, Lippincott Williams & Wilkins.
Keywords
bioresorbable cages, BMP-2, interbody fusion, lumbar spine, pig, polycaprolactone- tricalcium phosphate, stem cells
Source Title
Spine
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Series/Report No.
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Date
2011-10-01
DOI
10.1097/BRS.0b013e31822576a4
Type
Article