1. Classification of Early Onset Scoliosis (C-EOS) Has Almost Perfect Inter and Intra Observer Reliability
Micaela Cyr, BA
Tricia St. Hilaire, MPH
Zhaoxing Pan, PhD
George H. Thompson, MD
Children’s Spine Study Group
Growing Spine Study Group
Sumeet Garg, MD

2. Classification of Early Onset Scoliosis (C-EOS)
Williams, B.A., et al., Development and Initial Validation of the Classification of Early-Onset Scoliosis (C-EOS). The Journal of Bone & Joint Surgery, (16): p

3. Purpose
To evaluate the inter-observer and intra-observer reliability of the Classification of Early Onset Scoliosis (C-EOS) scheme

4. Methods
50 patient cases drawn from registry and used to create online survey
Survey sent to faculty, research coordinators, fellows involved with CSSG and GSSG
Surveys sent twice to test intra-observer reliability

5. Methods
Fleiss Kappa and Cohen’s Kappa used to asses inter-observer and intra-observer reliability respectively
Hypothesis: All categories would have Kappa value 0.75 or higher
Kappa value
Degree of agreement
<=0
Poor
0-0.2
Slight
Fair
Moderate
Substantial
Almost perfect

6. Results 36 total participants, 29 completed twice
Overall Fleiss Kappa for inter-observer reliability was almost perfect for etiology (0.84), Cobb angle (0.93), kyphosis angle (0.96)

7. Inter-observer reliability
*Fellows not included because there were only 2 responses

8. Intra-observer reliability
Overall Cohen’s Kappa for intra-observer reliability was almost perfect for etiology (0.92), Cobb angle (0.96), kyphosis angle (0.98)
Intra-observer reliability was almost perfect across all major categories for all groups

9. Conclusions
Etiology most difficult to classify, still demonstrates high reliability
High reliability with minimal training, varying degrees of familiarity with the system
C-EOS can be used as a reliable tool
-seems reasonable to conclude that reliability will rise as researchers use the tool more, become more familiar with it

10. References
1. Lenke, L.G., et al., Adolescent idiopathic scoliosis a new classification to determine extent of spinal arthrodesis. The Journal of Bone & Joint Surgery, (8): p
2. Clavien, P.A., et al., The Clavien-Dindo classification of surgical complications: five-year experience. Annals of surgery, (2): p
3. Sink, E.L., et al., Reliability of a complication classification system for orthopaedic surgery. Clinical Orthopaedics and Related Research®, (8): p
4. Williams, B.A., et al., Development and Initial Validation of the Classification of Early-Onset Scoliosis (C-EOS). The Journal of Bone & Joint Surgery, (16): p
5. Park, H.Y. The Classification for Early Onset Scoliosis (C-EOS) Predicts Timing of VEPTR Anchor Failure. in 2013 AAP National Conference and Exhibition American Academy of Pediatrics.
6. Cummings, R.J., et al., Interobserver Reliability and Intraobserver Reproducibility of the System of King et al. for the Classification of Adolescent Idiopathic Scoliosis*. The Journal of Bone & Joint Surgery, (8): p
7. Fleiss, J.L., B. Levin, and M.C. Paik, Statistical methods for rates and proportions. 2013: John Wiley & Sons.
8. Cohen, J. A coefficient of agreement for nominal scales. Educational and Psychological Measurement, (1): p
9. Landis, J.R. and G.G. Koch, The measurement of observer agreement for categorical data. biometrics, 1977: p