title: A new in vivo screening model for posterior spinal bone formation: comparison of ten calcium phosphate ceramic material treatments.
abstract: This study presents a new screening model for evaluating the influence of multiple conditions on the initial process of bone formation in the posterior lumbar spine of a large animal. This model uses cages designed for placement on the decorticated transverse process of the goat lumbar spine. Five conduction channels per cage, each be defined by a different material treatment, are open to both the underlying bone and overlying soft tissue. The model was validated in ten adult Dutch milk goats, with each animal implanted with two cages containing a total of ten calcium phosphate material treatments according to a randomized complete block design. The ten calcium phosphate ceramic materials were created through a combination of material chemistry (BCP, TCP, HA), sintering temperature (low, medium, high), calcination and surface roughness treatments. To monitor the bone formation over time, fluorochrome markers were administered at 3, 5 and 7 weeks and the animals were sacrificed at 9 weeks after implantation. Bone formation in the conduction channels was investigated by histology and histomorphometry of non-decalcified sections using traditional light and epifluorescent microscopy. According to both observed and measured bone formation parameters, materials were ranked in order of increasing magnitude as follows: low sintering temperature BCP (rough and smooth) approximately medium sintering temperature BCP approximately = TCP > calcined low sintering temperature HA > non-calcined low sintering temperature HA > high sintering temperature BCP (rough and smooth) > high sintering temperature HA (calcined and non-calcined). These results agree closely with those obtained in previous studies of osteoconduction and bioactivity of ceramics thereby validating the screening model presented in this study.
authors.affiliation: Department of Orthopaedics, G05.228, University Medical Center, P.O. Box 85500, NL 3508 GA, Utrecht, The Netherlands. c.e.wilson@tnw.utwente.nl
authors.forename: Clayton E
authors.initials: CE
authors.lastname: Wilson
authors.forename: Moyo C
authors.initials: MC
authors.lastname: Kruyt
authors.forename: Joost D
authors.initials: JD
authors.lastname: de Bruijn
authors.forename: Clemens A
authors.initials: CA
authors.lastname: van Blitterswijk
authors.forename: F Cumhur
authors.initials: FC
authors.lastname: Oner
authors.forename: Abraham J
authors.initials: AJ
authors.lastname: Verbout
authors.forename: Wouter J A
authors.initials: WJ
authors.lastname: Dhert
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry* / Q000627:therapeutic use; D002516:Ceramics / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use; D017886:Durapatite / Q000737:chemistry / Q000627:therapeutic use; D006041:Goats; D048091:Guided Tissue Regeneration / Q000379:methods; D006882:Hydroxyapatites / Q000737:chemistry / Q000627:therapeutic use; D020007:Implants, Experimental; D008159:Lumbar Vertebrae / Q000601:surgery*; D008422:Materials Testing / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000628:therapy; D013123:Spinal Fusion
chemical_list: D002130:Calcium Phosphates; D006882:Hydroxyapatites; C485817:beta-tricalcium phosphate; C094280:hydroxyapatite-tricalciumphosphate composite; D017886:Durapatite