title: The effect of increased microporosity on bone formation within silicate-substituted scaffolds in an ovine posterolateral spinal fusion model.
abstract: This study compared the bone forming capacity of the same formulation of silicate-substituted bone graft substitute materials with different microporosity in an instrumented posterolateral spinal fusion ovine model. Materials with a strut porosity of (i) 22.5% (SiCaP) or (ii) 36.0% (SiCaP(+)) were packed along either side of the spine. Bone apposition rates, % new bone formation, % bone-implant contact, and % graft resorption were quantified at 8, 12, and 24 weeks post surgery. Computed Tomography (CT) was used to grade the formation of fusion bridges between vertebrae. Results showed no significant difference in bone apposition rates, % new bone formation, and % bone-implant contact when the two materials were compared. However, at 8 weeks, a significantly higher CT score was obtained in the SiCaP(+) group (0.83 ± 0.17) when compared with the SiCaP group (0.17 ± 0.17; p = 0.027). Significantly less scaffold remained in the SiCaP(+) group at 12 weeks (p = 0.018). Both SiCaP and SiCaP(+) formulations augmented bone formation. Increasing the strut porosity did not significantly increase bone formation however, at 8 weeks it promoted the formation of more highly mineralized bone resulting in a significantly higher CT score, suggesting the bone tissue formed was more mature. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 805-814, 2017.
authors.affiliation: The Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, United Kingdom.
authors.forename: Melanie Jean
authors.initials: MJ
authors.lastname: Coathup
authors.affiliation: The Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, United Kingdom.
authors.forename: Gordon William
authors.initials: GW
authors.lastname: Blunn
authors.affiliation: Department of Materials, School of Engineering and Materials, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom.|ApaTech Ltd., 370 Centennial Avenue, Centennial Park, Elstree, Herts, WD6 3TJ, United Kingdom.
authors.forename: Charlie
authors.initials: C
authors.lastname: Campion
authors.affiliation: The Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, United Kingdom.
authors.forename: Chih-Yuan
authors.initials: CY
authors.lastname: Ho
authors.affiliation: Department of Materials, School of Engineering and Materials, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom.
authors.forename: Karin Angela
authors.initials: KA
authors.lastname: Hing
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology; D005260:Female; D008954:Models, Biological; D010012:Osteogenesis / Q000187:drug effects*; D016062:Porosity; D012756:Sheep; D017640:Silicates / Q000737:chemistry / Q000494:pharmacology; D013123:Spinal Fusion; D013131:Spine / Q000000981:diagnostic imaging / Q000378:metabolism; D054457:Tissue Scaffolds / Q000737:chemistry*; D014057:Tomography, X-Ray Computed
chemical_list: D018786:Bone Substitutes; D017640:Silicates
keywords: bone regeneration; bone substitute materials; calcium phosphate; osteoconduction; posterolateral spinal fusion; sheep model; strut porosity