title: The positive correlation between upper adjacent vertebral fracture and the kyphosis angle of injured vertebral body after percutaneous kyphoplasty: An in vitro study.
abstract: OBJECTIVE
  To investigate the correlation between the kyphosis angle of injured vertebral body and the risk of upper adjacent vertebral fracture after percutaneous kyphoplasty (PKP) using an osteoporotic vertebral compressed fracture model.
  
  
  METHODS
  24 functional spinal units (FSUs, T9 to L4) were selected from 6 elderly formalin preserved vertebral specimens to build the vertebral compressed fracture model. According to the kyphosis angle between the upper plate of upper vertebral body and the horizontal plane, group A (0°) and group B (20°) were defined, with each group comprised with 12 FSUs. The stiffness and fracture load were measured in both groups.
  
  
  RESULTS
  After PKP, the stiffness was (571.513 ± 83.373)N/mm and the fracture load was (1751.659 ± 112.291)N in group A, with both significantly higher than those of group B (stiffness, (307.706 ± 46.723)N/mm; fracture load, (1128.011 ± 125.417)N).
  
  
  CONCLUSIONS
  To reduce the risk of upper adjacent vertebral fracture, it is better to restore the height of injured vertebral body and decrease the angle of kyphosis to increase the capability of upper adjacent vertebral body against fracture.
authors.affiliation: Department of Spinal Surgery, the Affiliated Hospital of School of Medicine of Ningbo University, 247 Renming Road, Ningbo 315020, Zhejiang, China.
authors.forename: Jiye
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Spinal Surgery, the Affiliated Hospital of School of Medicine of Ningbo University, 247 Renming Road, Ningbo 315020, Zhejiang, China. Electronic address: jgq6424@hotmail.com.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Jiang
authors.affiliation: Department of Spinal Surgery, the Affiliated Hospital of School of Medicine of Ningbo University, 247 Renming Road, Ningbo 315020, Zhejiang, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Lu
authors.affiliation: Department of Spinal Surgery, the Affiliated Hospital of School of Medicine of Ningbo University, 247 Renming Road, Ningbo 315020, Zhejiang, China.
authors.forename: Chaolu
authors.initials: C
authors.lastname: Shi
authors.affiliation: Department of Spinal Surgery, the Affiliated Hospital of School of Medicine of Ningbo University, 247 Renming Road, Ningbo 315020, Zhejiang, China.
authors.forename: Kefeng
authors.initials: K
authors.lastname: Luo
authors.affiliation: Department of Spinal Surgery, the Affiliated Hospital of School of Medicine of Ningbo University, 247 Renming Road, Ningbo 315020, Zhejiang, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Yue
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D050815:Fractures, Compression / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D058498:Kyphoplasty; D007738:Kyphosis; D008159:Lumbar Vertebrae / Q000601:surgery*; D008953:Models, Anatomic; D058866:Osteoporotic Fractures / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology*; D016103:Spinal Fractures / Q000453:epidemiology / Q000601:surgery*; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000601:surgery*; D016474:Weight-Bearing
keywords: Biomechanics; Osteoporosis; Percutaneous kyphoplasty; Upper adjacent vertebral fracture