Construction and Validation of a Nomogram for Predicting the Adding-On Phenomenon Postoperatively for Adolescent Idiopathic Scoliosis: A Retrospective Study

World Neurosurg. 2025 Feb:194:123417. doi: 10.1016/j.wneu.2024.10.146. Epub 2024 Nov 26.

Abstract

Objective: To develop and validate a nomogram predicting the postoperative adding-on phenomenon in Lenke 1/2 adolescent idiopathic scoliosis patients, providing a quantitative tool for therapeutic benefit assessment and personalized risk prediction.

Methods: A retrospective analysis was conducted using clinical data from 213 patients. The least absolute shrinkage selection operator was applied to identify the best predictors. Multivariate logistic regression was used to construct a nomogram with a training set (80%), while a validation set (20%) was used for internal validation. The receiver operating characteristic curve, calibration curve, and decision curve analysis assessed the model's clinical utility.

Results: The model was constructed using the 4 best predictor variables: the number of vertebrae in the main thoracic curve, apical vertebra translation, last instrumented vertebra rotation, and Risser sign. The model's C-index was 0.932 (95% confidence interval, 0.8858-0.9775). Decision curve analysis indicated a clinically meaningful high-risk threshold between 0 and 1, and the calibration curve demonstrated satisfactory accuracy.

Conclusions: The model proved useful for predicting the occurrence of adding-on in Lenke 1/2 adolescent idiopathic scoliosis patients after surgery.

Keywords: Adding-on phenomenon; Adolescent idiopathic scoliosis; Nomogram; Risk factor.

Publication types

  • Validation Study

MeSH terms

  • Adolescent
  • Child
  • Female
  • Humans
  • Male
  • Nomograms*
  • Postoperative Complications*
  • Retrospective Studies
  • Scoliosis* / diagnostic imaging
  • Scoliosis* / surgery
  • Spinal Fusion*