title: The effect of kyphoplasty parameters on the dynamic load transfer within the lumbar spine considering the response of a bio-realistic spine segment.
abstract: BACKGROUND
  With an increasing prevalence of osteoporosis, physicians have to optimize treatment of relevant vertebral compression fractures, which have significant impact on the quality of life in the elder population. Retrospective clinical studies suggest that kyphoplasty, despite being a procedure with promising potential, may be related to an increased fracture risk of the adjacent untreated vertebrae.
  
  
  METHODS
  A bio-realistic model of a lumbar spine is introduced to determine the morbidity of cemented augmentation. The model was verified and validated for the purpose of the study and subjected to a dynamic finite element analysis. Anisotropic bone properties and solid ligamentous tissue were considered along with α time varying loading scenario.
  
  
  RESULTS
  The yielded results merit high clinical interest. Bi-pedicular filling stimulated a symmetrically developing stress field, thus comparing favourably to uni-pedicular augmentation which resulted in a non-uniform loading of the spine segment. An enslavement of the load transfer was also found to both patient bone mineral density and reinforcement-nucleous pulpous superimposition.
  
  
  CONCLUSIONS
  The investigation presented refined insight into the dynamic biomechanical response of a reinforced spine segment. The increase in the calculated occurring stresses was considered as non-critical in most cases, suggesting that prevalent fractures are a symptomatic condition of osteoporosis rather than a sequel of efficiently preformed kyphoplasty.
authors.affiliation: Department of Mechanical Engineering, Aristotle University Thessaloniki, 54124 Thessaloniki, Greece; Department of Mechanical Engineering, Frederick University, 1036 Nicosia, Cyprus. Electronic address: alextso@auth.gr.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tsouknidas
authors.forename: Savvas
authors.initials: S
authors.lastname: Savvakis
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Asaniotis
authors.forename: Kleovoulos
authors.initials: K
authors.lastname: Anagnostidis
authors.forename: Antonios
authors.initials: A
authors.lastname: Lontos
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Michailidis
mesh_terms: D016880:Anisotropy; D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000627:therapeutic use; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D058498:Kyphoplasty; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000503:physiopathology* / Q000601:surgery*; D008953:Models, Anatomic; D008954:Models, Biological; D011184:Postoperative Period; D012189:Retrospective Studies; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology*
chemical_list: D001843:Bone Cements
keywords: Adjacent spine levels; Cemented augmentation; Secondary fracture prevalence