NRS-BP NRS for back pain NRS-LP NRS for leg pain ODI Oswestry Disability Index PHC predictive hierarchical clustering PPV positive predictive value PROMs patient-reported outcome measures RF random forest ROC machine learning lumbar decompression surgery retrospective study synthetic electronic medical record ROC curve ACC accuracy ACS-NSQIP American College of Surgeons National Surgical Quality Improvement Program ANN artificial neural networks AUC area under the receiver operating characteristic curve COPD chronic obstructive pulmonary disease DNN deep neural networks HER electronic health records GBM gradient boosting machine GLM generalized linear model GLMnet elastic-net GLM LSS lumbar spinal stenosis MCID minimum clinically important difference ML machine learning NPV negative predictive value NRS numeric rating scale NRS-BP NRS for back pain NRS-LP NRS for leg pain ODI Oswestry Disability Index PHC predictive hierarchical clustering PPV positive predictive value PROMs patient-reported outcome measures RF random forest ROC receiver operating characteristic accuracy ACS-NSQIP American College of Surgeons National Surgical Quality Improvement Program ANN artificial neural networks AUC area under the receiver operating characteristic curve COPD chronic obstructive pulmonary disease DNN deep neural networks HER electronic health records GBM gradient boosting machine GLM generalized linear model GLMnet elastic-net GLM LSS lumbar spinal stenosis MCID minimum clinically important difference ML NPV negative predictive value NRS numeric rating scale