Noh SH, Ha Y, Obeid I, et al. - A retrospective comparative study was conducted to improve the predictability of global alignment and proportion (GAP) score after adult spinal deformity (ASD) surgery by adding BMI and bone mineral density (BMD). Researchers enrolled a total of 203 consecutive patients with ASD who had undergone corrective fusion of more than 4 levels between January 2009 and December 2016, and were followed up for more than 2 years. The area under the receiver operating characteristic curve was estimated to compare the ability of the Scoliosis Research Society (SRS)-Schwab classification, age-adjusted alignment goals, GAP score, and modified global alignment and proportion scoring with BMI and BMD (GAPB) to prognosticate mechanical failure. Researchers developed and validated GAPB to randomized patients to derivation (n=125, 61.6%) and validation (n=78, 38.4%) cohorts. The GAPB system, which includes BMI and BMD, exhibited enhanced predictability for predicting mechanical complications in comparison with the GAP score. The results recommended that surgeons should keep in mind the utility of bone quality and BMI as well as proportional alignment.