title: Risk factor analysis of proximal junctional kyphosis after posterior fusion in patients with idiopathic scoliosis.
abstract: METHODS
  A retrospective analysis of 150 adolescents who underwent spinal fusion for idiopathic scoliosis.
  
  
  OBJECTIVE
  To analyse the incidence of the postoperative proximal junctional kyphosis after posterior fusion to the upper thoracic vertebra in adolescents with idiopathic scoliosis and to explore its risk factors.
  
  
  BACKGROUND
  The reported incidence of the proximal junctional kyphosis after the posterior fusion in patients with idiopathic scoliosis varies depending on surgical methods and strategies adopted by the institution.
  
  
  METHODS
  The changes in the Cobb angle of the proximal junctional kyphosis on the lateral spine X-ray were measured and the presence of PJK was recorded. The risk factors were screened using statistical analysis.
  
  
  RESULTS
  PJK occurred in 35 out of 123 patients with an overall incidence of 28%. Among them, 28 patients (80%) experienced PJK within 1.5 years after surgery. The PJK-inducing factors included greater than 10 degrees intraoperative decrease in thoracic kyphosis, thoracoplasty, the use of a pedicle screw at the top vertebra, autogenous bone graft and fusion to the lower lumbar vertebra (below L2).
  
  
  CONCLUSIONS
  There is a high incidence of postoperative proximal junctional kyphosis after posterior fusion to the upper thoracic vertebra within 1.5 years after surgery in adolescents with idiopathic scoliosis. In order to reduce its incidence, the risk factors for PJK should be carefully evaluated before surgery.
authors.affiliation: Department of Orthopaedic Surgery, Yantai Shan Hospital, Yantai City, China.
authors.forename: Jingjie
authors.initials: J
authors.lastname: Wang
authors.forename: Yongfei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Binghua
authors.initials: B
authors.lastname: Shen
authors.forename: Chuanfeng
authors.initials: C
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Li
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D015994:Incidence; D016268:Internal Fixators / Q000009:adverse effects*; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012600:Scoliosis / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D013905:Thoracoplasty / Q000009:adverse effects; D016896:Treatment Outcome