Reliability of Coronal Curvature Measures in Premature Scoliosis: Comparison of 4 Methods Using Inverted Digital Luminescence Radiography

Abstract

STUDY DESIGN: Observational study with 4 examiners. OBJECTIVE: To improve the reproducibility and reliability of coronal curvature measurements. SUMMARY OF BACKGROUND DATA: Several different methods have been developed to measure coronal curvature. Inverted digital luminescence radiography may be an additional technique to improve the reliability of measurement methods. METHODS: A total of 114 whole spine posterior-anterior radiographs were collected to compare the reliability of 4 measurement methods used in early onset scoliosis. Each radiograph was measured twice by each of 4 examiners using 4 measurement methods with normal and inversion views. Data were analyzed to determine inter- and intraobserver reliabilities. RESULTS: For all 4 methods, the overall intraobserver ICCs were greater than 0.926 and the interobserver ICCs were greater than 0.902, indicating excellent reliability. When intraobserver reliability was assessed in relation to scoliosis severity (<20°, 20°-40°, and >40°), the ICCs were higher for greater degrees of curvature; nonetheless, these values were in the excellent range for all methods and were higher for inversion (>0.908) than normal (>0.838) radiographs. For interobserver comparisons, the ICCs were better for the pedicle method (normal: >0.795, inversion: >0.831) than for the other methods (normal: >0.532, inversion: >0.590), with inverted digital luminescence radiography showing the higher ICCs. CONCLUSION: Inversion radiographs showed high reliability and may increase reliability in cases of less deformed spines. In addition, the pedicle method led to higher ICCs for all measurements regardless of severity, especially on inversion radiographs.