title: Percutaneous vertebroplasty: a new animal model.
abstract: Percutaneous vertebroplasty (PVP) is a minimally invasive surgical procedure and is frequently performed in humans who need surgical treatment of vertebral fractures. PVP involves cement injection into the vertebral body, thereby providing rapid and significant pain relief.
  
  
  
  The testing of novel biomaterials depends on suitable animal models. The aim of this study was to develop a reproducible and safe model of PVP in sheep.
  
  
  
  This study used ex vivo and in vivo large animal model study (Merino sheep).
  
  
  
  Ex vivo vertebroplasty was performed through a bilateral modified parapedicular access in 24 ovine lumbar hemivertebrae, divided into four groups (n=6). Cerament (Bone Support, Lund, Sweden) was the control material. In the experimental group, a novel composite was tested-Spine-Ghost-which consisted of an alpha-calcium sulfate matrix enriched with micrometric particles of mesoporous bioactive glass. All vertebrae were assessed by micro-computed tomography (micro-CT) and underwent mechanical testing. For the in vivo study, 16 sheep were randomly allocated into control and experimental groups (n=8), and underwent PVP using the same bone cements. All vertebrae were assessed postmortem by micro-CT, histology, and reverse transcription-polymerase chain reaction (rt-PCR). This work has been supported by the European Commission under the 7th Framework Programme for collaborative projects (600,000-650,000 USD).
  
  
  
  In the ex vivo model, the average defect volume was 1,275.46±219.29 mm3. Adequate defect filling with cement was observed. No mechanical failure was observed under loads which were higher than physiological. In the in vivo study, cardiorespiratory distress was observed in two animals, and one sheep presented mild neurologic deficits in the hind limbs before recovering.
  
  
  
  The model of PVP is considered suitable for preclinical in vivo studies, mimicking clinical application. All sheep recovered and completed a 6-month implantation period. There was no evidence of cement leakage into the vertebral foramen in the postmortem examination.
authors.affiliation: Departamento de Medicina Veterinária (DMV), Escola de Ciências e Tecnologia (ECT), Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), University of Évora, Apartado 94, 7002-554 Évora, Portugal. Electronic address: teresoliveira@uevora.pt.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Oliveira
authors.affiliation: Departamento de Medicina Veterinária (DMV), Escola de Ciências e Tecnologia (ECT), Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), University of Évora, Apartado 94, 7002-554 Évora, Portugal.
authors.forename: José
authors.initials: J
authors.lastname: Potes
authors.affiliation: Departamento de Medicina Veterinária (DMV), Escola de Ciências e Tecnologia (ECT), Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), University of Évora, Apartado 94, 7002-554 Évora, Portugal.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Queiroga
authors.affiliation: Departamento de Zootecnia, Escola de Ciências e Tecnologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Apartado 94, 7002-554 Évora, Portugal.
authors.forename: José L
authors.initials: JL
authors.lastname: Castro
authors.affiliation: Departamento de Zootecnia, Escola de Ciências e Tecnologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Apartado 94, 7002-554 Évora, Portugal.
authors.forename: Alfredo F
authors.initials: AF
authors.lastname: Pereira
authors.affiliation: JRI Orthopaedics Limited, 18 Churchill Way, Sheffield, S35 2PY, UK.
authors.forename: Sarrawat
authors.initials: S
authors.lastname: Rehman
authors.affiliation: School of Mechanical and Systems Engineering, Newcastle University, Stephenson Building, Claremont Rd, Newcastle upon Tyne, NE1 7RU, UK.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Dalgarno
authors.affiliation: Biomechanics Research Group, Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering of the University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Ramos
authors.affiliation: Politecnico di Torino, Corso Duca degli Abruzzi, 24-10129, Torino, Italy; Consorzio per la Ricerca e l'Educazione Permanente (Corep), Sede legale Via Ventimiglia, 115-10126, Torino, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Vitale-Brovarone
authors.affiliation: Departamento de Medicina Veterinária (DMV), Escola de Ciências e Tecnologia (ECT), Apartado 94, 7002-554 Évora, Portugal; Complexo de Laboratórios Tecnológicos (CICECO), Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Joana C
authors.initials: JC
authors.lastname: Reis
mesh_terms: D000818:Animals; D001843:Bone Cements / Q000627:therapeutic use; D002133:Calcium Sulfate / Q000627:therapeutic use; D004195:Disease Models, Animal; D004338:Drug Combinations; D017886:Durapatite / Q000627:therapeutic use; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation / Q000379:methods*; D012756:Sheep; D016103:Spinal Fractures / Q000601:surgery; D054854:Vertebroplasty / Q000295:instrumentation / Q000379:methods*
chemical_list: D001843:Bone Cements; D004338:Drug Combinations; C582328:cerament; D017886:Durapatite; D002133:Calcium Sulfate
keywords: Animals models; Biomaterials; Micro-CT; Ovine; Parapedicular access; Percutaneous vertebroplasty