title: Biomechanical comparison of kyphoplasty with different bone cements.
abstract: METHODS
  Ex vivo biomechanical study.
  
  
  OBJECTIVE
  To compare the biomechanical properties of isolated, fractured, osteoporotic vertebral bodies after treatment by kyphoplasty with one of two cements: alpha-tri-calcium phosphate cement (Biopex-R; Mitsubishi Materials Corp., Tokyo, Japan) or polymethylmethacrylate (Simplex P; Stryker-Howmedica-Osteonics, Mahwah, NJ).
  
  
  BACKGROUND
  Kyphoplasty and vertebroplasty typically use polymethylmethacrylate cements for the treatment of osteoporotic compression fractures. Scant information exists regarding the use of alternative cements in kyphoplasty.
  
  
  METHODS
  Simulated compression fractures were created in 24 vertebral bodies (T6-T9, L2-L5) harvested from three female cadavers. Vertebral bodies were assigned to one of two groups: kyphoplasty with Biopex-R or kyphoplasty with Simplex P. The kyphoplasty treatment consisted of inserting bone tamps bipedicularly into each vertebral body, inflating the tamp, and filling the created void with Biopex-R or Simplex P. Pretreatment and post-treatment heights were measured, and the repaired vertebral bodies were recompressed to determine posttreatment strength and stiffness values. Differences were checked for significance (P < 0.05) using a repeated-measures analysis of variance followed by Tukey's test.
  
  
  RESULTS
  Kyphoplasty with Biopex-R restored strength in the lumbar and thoracic vertebral bodies. Kyphoplasty with Simplex P displayed significantly greater posttreatment strength than initial strength in the thoracic region. Vertebral bodies augmented with either cement were significantly less stiff than their initial conditions, except for the thoracic vertebrae treated with Simplex P, in which stiffness was restored. There was no significant difference in percentage of height restored between the cement treatments.
  
  
  CONCLUSIONS
  Kyphoplasty with either cement restored initial strength. In general, stiffness was not restored.
authors.affiliation: Orthopaedic Instrumentation Laboratory, Department of Orthopaedic Surgery, Johns Hopkins University/Johns Hopkins Bay-view Medical Center, Baltimore, MD 21224-2780, USA.
authors.forename: Seiji
authors.initials: S
authors.lastname: Tomita
authors.forename: Sean
authors.initials: S
authors.lastname: Molloy
authors.forename: Louis E
authors.initials: LE
authors.lastname: Jasper
authors.forename: Muneaki
authors.initials: M
authors.lastname: Abe
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Belkoff
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001843:Bone Cements; D002130:Calcium Phosphates; D005260:Female; D006801:Humans; D020366:Methylmethacrylate; D010024:Osteoporosis / Q000150:complications; D011859:Radiography; D016103:Spinal Fractures / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; C485828:alpha-tricalcium phosphate; D020366:Methylmethacrylate