Comment on “Responsiveness and minimal clinically important changes of surface topography parameters in adolescents with idiopathic scoliosis: results from the schroth exercise trial”
摘要
To offer constructive comments on the recent study by Mohamed et al. published in European Spine Journal, with a focus on the clinical detectability of the proposed minimal clinically important changes (MCICs) for surface topography (ST) parameters, the robustness of the anchoring method, and the differential responsiveness between thoracic and lumbar curve subgroups, aiming to provide reference for future research on ST application in conservative management of adolescent idiopathic scoliosis (AIS).
MethodsThis commentary was developed through logical analysis of the original study data and cross-referencing with existing literature, addressing three key aspects: (1) a theoretical comparison between the reported MCIC values and the inherent measurement error (minimal detectable change, MDC) of ST systems to evaluate their clinical discriminability; (2) an examination of the limitations of using the Global Rating of Change (GRC) scale as a single anchoring tool, with suggestions for incorporating the SRS-22 self-image domain and region-specific parameters as complementary measures; and (3) an interpretation of the discordance between ST parameter changes and patient perception in the thoracic subgroup, supported by independent evidence from postoperative AIS studies on the correlation between radiographic parameters and self-image
ResultsThe MCIC values proposed in the original study—0.27 mm for RMS and 0.49 mm for MaxDev—are substantially smaller than the known measurement errors of most ST systems. Without reporting the MDC, such "clinically important" changes may be indistinguishable from random noise. The correlation between GRC scores and ST parameter changes was only moderate (r ≈ -0.5), and the use of a single global parameter failed to capture shoulder and waist asymmetries, limiting its ability to reflect clinically meaningful improvement in thoracic curves. Independent postoperative evidence supports the authors' hypothesis that lumbar curve changes are more readily perceived by patients, as residual thoracolumbar/lumbar curve magnitude, but not the main thoracic curve, correlates with SRS-22 self-image scores.
ConclusionThe original study provides pioneering data on ST parameters in AIS; however, the clinical application of its MCIC values warrants cautious interpretation. Future studies should systematically report MDC to establish measurement reliability, employ multi-dimensional anchoring tools (e.g., SRS-22), and develop region-specific or composite ST parameters, particularly optimized for patients with thoracic curves, to more accurately capture patient-perceived clinical improvement.