Rasterstereography versus radiography for assessing shoulder balance in idiopathic scoliosis: A validation study relative to patients' self-image.

BACKGROUND: Shoulder imbalance is a problem for scoliosis patients. Rasterstereography uses radiation-free surface topography to follow up these patients. Its use for assessing shoulder level has not been investigated earlier.

OBJECTIVE: This study aimed to determine the accuracy of shoulder assessment using rasterstereography (versus radiography) and to analyze its relationship with patients' self-image.

METHODS: In a cross-sectional setting, the reliability and validity of five rasterstereographic shoulder variables were measured in comparison with six radiographic shoulder parameters, using correlation analysis. The patients' self-perception was documented using the Scoliosis Research Society-22 (SRS-22) questionnaire and Trunk Appearance Perception Scale (TAPS).

RESULTS: Forty patients were included in the study. The test-retest reliability of all rasterstereographic shoulder parameters was excellent (ICC > 0.95). The validity was moderate in comparison with six radiographic parameters (highest coefficient: 0.582). The radiographic and rasterstereographic shoulder levels correlated with the results in the SRS-22 questionnaire (highest coefficient: -0.463) and TAPS (highest coefficient: 0.413).

CONCLUSIONS: Rasterstereography is a reliable and valid method for assessing shoulder level in idiopathic scoliosis. The parameters can be recommended as a complement to radiography and clinical evaluation for follow-up purposes. Radiographic and rasterstereographic shoulder parameters are significantly related to patients' self-perception. Shoulder variables thus need to be considered in scoliosis patients.