Measurement Properties of Surface Topography for Scoliosis Assessment: A Systematic Review and Meta-analysis

To comprehensively evaluate the validity, responsiveness, and feasibility of surface topography (ST) indices and provide insights into their potential integration into clinical scoliosis assessment.

A systematic literature search was performed in PubMed and Web of Science for studies published between January 2010 and April 2024.

Studies reporting on the validity, responsiveness, and feasibility of ST indices were screened and selected by 2 independent researchers.

Data extraction and analysis followed the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline framework. Two independent reviewers extracted study characteristics, methodological quality, measurement properties, and evidence levels. Methodological quality was assessed using the COSMIN Risk of Bias checklist, supplemented with Quality Assessment of Diagnostic Accuracy Studies-2 items. Measurement properties were assessed using COSMIN quality criteria, and the quality of evidence was graded using the Modified Grading of Recommendations Assessment, Development, and Evaluation system approach. A meta-analysis was conducted to synthesize the measurement properties.

A total of 23 studies were included. Scoliosis angle and asymmetry index received sufficient ratings for criterion validity, supported by high-quality evidence. The construct validity of both thoracic kyphosis and lumbar lordosis in the sagittal plane, when compared with similar parameters measured from X-rays, was rated as sufficient with high-level evidence. However, compared with measurements from X-ray or magnetic resonance imaging (MRI), the construct validity of vertebral rotation was rated as insufficient with low-quality evidence. For responsiveness, the scoliosis angle compared with the Cobb angle in the coronal plane showed inconsistent results, with the overall quality of evidence rated as very low.

This review highlighted the potential of ST as a radiation-free and informative tool for scoliosis assessment, particularly in screening settings. Although the scoliosis angle and asymmetry index demonstrated sufficient criterion validity, challenges remain regarding vertebral rotation validity, responsiveness, and correlations with patient-reported outcomes. Further advancements in standardization and methodological quality are necessary for the broader clinical adoption of ST systems.