Blasting BMAC: a novel therapy to improve healing in fusion surgery

S. Stewart, A. Darwood, C. Higgins, S. Masouros, A. Ramasamy

Introduction: Fusion represents an effective treatment option in patients affected by end-stage arthritis. To minimise the risk of non-union following fusion, biological preparations such as bone marrow aspirate concentrate (BMAC) are commonly used intra-operatively. Mechanotransduction represents an emerging field of research whereby physical stimuli can be used to modulate the behaviour and differentiation of cells. Blast waves (a subtype of shock waves) are one such physical stimulus. The aim of this study was to investigate whether the osteogenic potential of BMAC can be enhanced using a blast wave, and thus improve its efficacy in fusion surgery.
Methods: Human BMAC samples were obtained from three healthy patients and exposed to a single blast wave (peak overpressure= 50psi), before being placed in a suspension of mesenchymal stem cells, to represent the biological environment of the fusion site. Three test groups were used: MSC (the experimental control); MSC + BMAC; MSC + BMAC + blast wave. Calcium mineralisation assays were performed on the MSCs on Day 7 and 14 to assess for osteoblastic transformation.
Results: Calcium mineralisation on Day 7 was significantly increased in the MSC + BMAC group compared to the MSC group (mean percentage change 42.12 vs 0.0, p=0.012). The MSC + BMAC + blast wave group also demonstrated significantly increased levels compared to the MSC + BMAC group (84.56 vs. 42.14, p=0.039). The difference in calcium mineralisation between the MSC and MSC + BMAC + blast wave groups was strongly significant (0.00 vs. 84.56, p=0.003).  
Conclusion: Exposure of BMAC to a single blast wave enhances its osteogenic potential. This represents a potential novel way to improve healing following fusion surgery and reduce the rates of non-union.