Abstract
Dear Editor,
Zwingenberger et al present an important retrospective analysis of early night-time bracing in mild Adolescent Idiopathic Scoliosis (AIS). 1 Their focus on the 15°–25° Cobb angle range is timely, as this interval has historically been underexplored despite being critical for early intervention, particularly with a dual-center design and long follow-up period providing a strong foundation for the analysis.2,3
The high compliance rate achieved with the Dresdner Night-Time Brace (DNTB) is interesting. By limiting application to approximately 8 h during sleep, the authors demonstrate that adherence can be substantially improved compared to full-time bracing. This is clinically significant because compliance has emerged as the strongest predictor of treatment success. 4
The study also highlights the biomechanical effectiveness of the DNTB, achieving a mean in-brace correction of 60.9%. Interestingly, correction correlated moderately with initial curve magnitude but not with age or sex, suggesting that brace design and fit may matter more than demographics. This observation encourages us to refine brace fabrication protocols and to personalize correction targets based on baseline curve severity. 5
However, the reliance on self-reported compliance is a notable limitation. Without objective monitoring, such as temperature or pressure sensors, adherence data may be vulnerable to bias. Building open this study, future studies should incorporate wearable technologies to capture real wear-time and explore dose–response relationships between hours worn and curve stabilization. This would allow moving beyond categorical compliance groups toward more nuanced adherence metrics. 6
Another methodological issue is the timing and positioning of radiographic assessments. In-brace correction was measured supine at six to nine months, which may miss immediate mechanical effects and blend them with biological adaptation. Addition of early upright in-brace imaging, ideally within weeks of initiation, could provide a clearer benchmark of brace performance and help identify patients needing rapid adjustments.
The study’s outcome definitions, based on ±5° thresholds, are standard but may be problematic in mild curves where measurement error is proportionally larger. Continuous modeling of Cobb angle trajectories, supplemented by inter-rater reliability data, would strengthen confidence in the reported stabilization rates. This refinement could help distinguish true biological change from technical variability.
Curve pattern and sagittal alignment can be analyzed in future studies, give that these factors are highly relevant to brace biomechanics. Thoracic vs thoracolumbar curves, apical rotation, and sagittal balance can all influence correction and tolerability. 7 Incorporating low-radiation surrogates such as scoliometer readings, ultrasound, or EOS imaging would enrich future datasets without excessive exposure.
The absence of a comparator group, such as patients treated with other braces or observed without bracing, limits external validity. A multicenter registry with standardized inputs including brace type, curve pattern, Risser stage, sensor-verified wear-time may enable head-to-head comparisons.
Zwingenberger et al have opened an important door; the next step is prospective, patient-centered refinement. Despite this, the study persuasively argues that mild AIS should not be passively observed until 25°. Early night-time bracing is practical, tolerable, and effective when compliance is cultivated. The challenge is to standardize measurement, modernize adherence monitoring, and integrate behavioral supports.
