title: Reproducibility measuring the angle of proximal junctional kyphosis using the first or the second vertebra above the upper instrumented vertebrae in patients surgically treated for scoliosis.
abstract: METHODS
  A historical cohort study.
  
  
  OBJECTIVE
  To evaluate the reproducibility of this measure in proximal junctional kyphosis (PJK) and to determine whether differences exist between first and second vertebrae angles.
  
  
  BACKGROUND
  There are no previous studies on the precision and accuracy of selecting the first or the second vertebra above the upper instrumented vertebrae to determine the degree of spinal angulation after surgery.In several studies, the first or the second vertebrae above the upper instrumented vertebrae (UIV) have been selected to measure the angle of PJK in a surgical setting. However, to our knowledge, no studies have addressed the reliability of this measure.We aimed to evaluate the reproducibility of this measure in PJK and to determine whether differences exist between first and second vertebrae angles.
  
  
  METHODS
  A total of 38 randomly ordered radiologic digital images were obtained at 2 different times from 19 consecutive patients (aged 18.4 +/- 6.0 years at intervention) surgically treated for scoliosis. Using these images in a blinded manner, 2 surgeons independently measured angles at both the first and second vertebrae above the UIV. The measures were repeated in different periods to test intra- and intersurgeon concordances.
  
  
  RESULTS
  For 152 measures, intrasurgeon concordance correlation coefficients ranged from 0.78 to 0.92 (high to very high reproducibility) and comparative intersurgeon concordance correlation coefficients ranged from 0.55 to 0.80 (moderate to high reproducibility). No differences were found between the first and the second vertebrae angles.
  
  
  CONCLUSIONS
  Good reproducibility and agreement using the first and second vertebrae above the UIV to measure the angle of PJK was found in this study.
authors: Department of Orthopedic Surgery, Hospital Universitario de Canarias, University of La Laguna, La Laguna, Santa Cruz de Tenerife, Spain. cristisacra@yahoo.es
authors: Cristina
authors: C
authors: Sacramento-Domínguez
authors: Raquel
authors: R
authors: Vayas-Díez
authors: Luis
authors: L
authors: Coll-Mesa
authors: Angel Piñera
authors: AP
authors: Parrilla
authors: Manuel
authors: M
authors: Machado-Calvo
authors: Javier Ara
authors: JA
authors: Pinilla
authors: Alejandro Jiménez
authors: AJ
authors: Sosa
authors: Guillermo de la Barreda
authors: Gde L
authors: López
mesh_terms: D000293:Adolescent; D001863:Bone Screws; D002648:Child; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D011859:Radiography; D015203:Reproducibility of Results; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016037:Single-Blind Method; D013123:Spinal Fusion / Q000379:methods; D013131:Spine / Q000000981:diagnostic imaging* / Q000473:pathology*; D055815:Young Adult