Use of Pre-Operative SRS-22r Profiles to Predict Clinically Meaningful Improvement after AIS Surgery: a Detailed Multivariable MCID Analysis in 189 Patients

Retrospective study. The aim of this study is to evaluate the predictive ability of pre-operative Scoliosis Research Society-22 revised questionnaire (SRS-22r) domains for achieving Minimum clinically important difference (MCID) at 2 years after adolescent idiopathic scoliosis (AIS) surgery. Understanding which AIS will achieve clinically meaningful postoperative benefit remains challenging, particularly when counseling families about expected changes in health-related quality of life. MCID thresholds for SRS-22r domains have been described, but it is unclear how baseline profiles can be leveraged to anticipate meaningful improvement at 2 years after surgery. A retrospective analysis of AIS patients undergoing posterior spinal fusion was performed. Pre-operative, 1-year, and 2-year SRS-22r domain scores (Function, Pain, Self-Image, Mental Health), VAS pain, and ODI were collected. MCID was defined as a ≥ 1-point improvement from baseline to 2 years. Univariate and multivariable logistic regression models were constructed, and model performance was assessed using ROC–AUC and calibration curves. ROC-based threshold optimization using Youden’s J statistic, and fivefold cross-validation was used to derive clinically interpretable pre-operative cut-points. In total, 189 patients were analyzed for the study. All SRS-22r domains improved significantly at 2 years, with the greatest absolute gain in Self-Image 64.9