title: Reliability and reproducibility analysis of the Cobb angle and assessing sagittal plane by computer-assisted and manual measurement tools.
abstract: BACKGROUND
  Although many studies on reliability and reproducibility of measurement have been performed on coronal Cobb angle, few results about reliability and reproducibility are reported on sagittal alignment measurement including the pelvis. We usually use SurgimapSpine software to measure the Cobb angle in our studies; however, there are no reports till date on its reliability and reproducible measurements.
  
  
  METHODS
  Sixty-eight standard standing posteroanterior whole-spine radiographs were reviewed. Three examiners carried out the measurements independently under the settings of manual measurement on X-ray radiographies and SurgimapSpine software on the computer. Parameters measured included pelvic incidence, sacral slope, pelvic tilt, Lumbar lordosis (LL), thoracic kyphosis, and coronal Cobb angle. SPSS 16.0 software was used for statistical analyses. The means, standard deviations, intraclass and interclass correlation coefficient (ICC), and 95% confidence intervals (CI) were calculated.
  
  
  RESULTS
  There was no notable difference between the two tools (P = 0.21) for the coronal Cobb angle. In the sagittal plane parameters, the ICC of intraobserver reliability for the manual measures varied from 0.65 (T2-T5 angle) to 0.95 (LL angle). Further, for SurgimapSpine tool, the ICC ranged from 0.75 to 0.98. No significant difference in intraobserver reliability was found between the two measurements (P > 0.05). As for the interobserver reliability, measurements with SurgimapSpine tool had better ICC (0.71 to 0.98 vs 0.59 to 0.96) and Pearson's coefficient (0.76 to 0.99 vs 0.60 to 0.97). The reliability of SurgimapSpine measures was significantly higher in all parameters except for the coronal Cobb angle where the difference was not significant (P > 0.05).
  
  
  CONCLUSIONS
  Although the differences between the two methods are very small, the results of this study indicate that the SurgimapSpine measurement is an equivalent measuring tool to the traditional manual in coronal Cobb angle, but is advantageous in spino-pelvic measurement in T2-T5, PT, PI, SS, and LL.
authors: Weifei
authors: W
authors: Wu
authors: Jie
authors: J
authors: Liang
authors: Department of Orthopedics, the People's Hospital of Three Gorges University, the First People's Hospital of Yichang, Yichang, China. yuanlidu19@sina.com.
authors: Yuanli
authors: Y
authors: Du
authors: Xiaoyi
authors: X
authors: Tan
authors: Xuanping
authors: X
authors: Xiang
authors: Wanhong
authors: W
authors: Wang
authors: Neng
authors: N
authors: Ru
authors: Jinbo
authors: J
authors: Le
mesh_terms: D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging*; D008141:Lordosis / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D015588:Observer Variation; D010384:Pelvic Bones / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012447:Sacrum / Q000000981:diagnostic imaging*; D012600:Scoliosis / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D012984:Software; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging*