title: Interobserver agreement in fusion status assessment after instrumental desis of the lower lumbar spine using 64-slice multidetector computed tomography: impact of observer experience.
abstract: OBJECTIVE
  Persistent lower back pain after instrumental posterolateral desis may arise from incomplete fusion. We investigate the impact of experience on interobserver agreement in fusion estimation.
  
  
  METHODS
  Four independent observers, two residents and two musculoskeletal radiologists, reviewed dedicated lumbar 64-MDCT scans and scored vertebral levels 1-5 after Glassman's grades, 1: solid bilateral fusion, 2: solid unilateral fusion, 3: partial bilateral fusion, 4: partial unilateral fusion, 5: non-fusion. We investigated two simplifying dichotomizations, solid bilateral fusion (Glassman 1) versus all others and uni- or bilateral fusion (Glassman 1-2) versus partial or non-fusion.
  
  
  RESULTS
  Thirty-six patients with 61 operated lumbar levels were included. Interobserver agreement rates for four observers using Glassman's system were fair (kappa 0.32), either dichotomization showed moderate agreement (kappa 0.53 and 0.59). Observer pairs had comparable prevalence adjusted interobserver agreement rates (residents: PABAK 0.67 and 0.54; consultants: PABAK 0.57 and 0.71).
  
  
  CONCLUSIONS
  Difference in observer experience seems of minor impact.
authors.affiliation: Department of Radiology, Diagnostic Centre, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, Copenhagen, Denmark.
authors.forename: Borislav
authors.initials: B
authors.lastname: Laoutliev
authors.forename: Inger
authors.initials: I
authors.lastname: Havsteen
authors.forename: Birthe Højlund
authors.initials: BH
authors.lastname: Bech
authors.forename: Eva
authors.initials: E
authors.lastname: Narvestad
authors.forename: Hanne
authors.initials: H
authors.lastname: Christensen
authors.forename: Anders
authors.initials: A
authors.lastname: Christensen
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D012008:Recurrence; D013123:Spinal Fusion; D016896:Treatment Outcome