CLINICAL APPLICATION OF SURFACE TOPOGRAPHY IN SCOLIOSIS

Introduction Monitoring of scoliosis is traditionally done with radiographs, which can be associated with an increased risk of cancer secondary to multiple exposures over many years. This study investigated whether the findings from surface topography can be used to monitor scoliosis curves and how much this method affects outcome scores in patients with scoliosis. This study therefore had two subsets: (1) to investigate whether lateral asymmetry (LA) from ISIS2 surface topography can predict radiographic Cobb angle, providing an alternative non-invasive means of monitoring patients with scoliosis (LA and Cobb subset); and (2) to establish the relationships between the magnitude of the deformity in scoliosis, measured by Cobb angle on radiograph and volumetric asymmetry (VA) with the ISIS2 surface topography, and the patient perception of self-image and mental health, measured with SRS-22 scores (Cobb, VA, and SRS subset). Methods In the LA and Cobb subset, 72 untreated patients with scoliosis (77 curves) with a Cobb angle of 55° or less were included in the study. They had clinical assessment, Cobb angle measurement taken from a standard radiograph, and surface topography done on the same day. A comparison of Cobb angle and LA was done. In the Cobb, VA, and SRS subset, 89 untreated patients with scoliosis were included in the study. They had clinical assessment, Cobb angle measurement of radiograph, and surface topography done on the same day along with SRS-22 questionnaires. A comparison correlation of SRS scores for function, pain, self-image, and mental health against Cobb angle and VA was undertaken. All statistical analysis was done with software R. Results In the LA and Cobb subset, for Cobb angle less than 55° on radiograph, ISIS2 was able to predict the Cobb angle within 13°. In the VA, Cobb, and SRS subset, Cobb angle contributed only about 10% to self-image, whereas VA contributed 14%. Cobb angle contributed about 6·2% to mental health, whereas VA contributed 8·6%. Conclusions Cobb angles display poor reliability, with estimates ranging from 3° to 10°. Even so, the 95% CIs on the prediction of Cobb angle from ISIS2 LA are too wide to use it alone to monitor spinal curvature. Whether or not LA is capable of monitoring change in curvature will be investigated as more longitudinal data are built up. VA correlates better with both mental health and self-image than does Cobb angle, but the correlation is still poor. Neither Cobb angle nor VA can be used to predict patient9s self-image or mental health. We are pursuing this study further to look at other parameters that may affect SRS-22 such as sex, age, type of deformity, waist asymmetry, and shoulder asymmetry.