Adult spinal deformity surgical decision-making score. Part 2: development and validation of a scoring system to guide the selection of treatment modalities for patients above 40 years with adult spinal deformity

Purpose We aimed to develop and internally validate a scoring system, the adult spinal deformity surgical decision-making (ASD-SDM) score, to guide the decision-making process for ASD patients aged above 40 years. Methods A multicentre prospective ASD database was retrospectively reviewed. The scoring system was developed using data from a derivation set and was internally validated in a validation set. The performance of the ASD-SDM score for predicting surgical management was assessed using the area under the receiver operating characteristic curve (AUC). Results A total of 702 patients were included for analysis in the present study. The scoring system developed based on 562 patients, ranging from 0 to 12 points, included five parameters: leg pain scored by the numerical rating scale; pain and self-image domains in the Scoliosis Research Society-22 score; coronal Cobb angle; and relative spinopelvic alignment. Surgical indication was graded as low (score 0 to 4), moderate (score 5 to 7), and high (score 8 to 12) groups. In the validation set of 140 patients, the AUC for predicting surgical management according to the ASD-SDM score was 0.797 (standard error = 0.037, P