Alhaug OK, Dolatowski FC, , et al. - A retrospective analysis of prospective national spine registry data with 12-months follow-up was performed to evaluate changes in standard patient-reported outcome measures that most accurately identified failure and worsening after surgery for lumbar spinal stenosis. Researchers examined 10,822 patients aged 50 years and older who operated in Norway during a decade, and 8,258 (76%) responded 12 months after surgery. They computed final scores, absolute changes, and percentage changes for Oswestry Disability Index, the Numeric Rating Scale for back and leg pain, and EuroQol-5D. The data exhibited Oswestry Disability Index (ODI) derivates were most accurate to distinguish both failures and worsening after surgery for degenerative lumbar spinal stenosis in this national register study. Use of ODI percentage change and ODI final score are recommended for further studies of failure and worsening in elective spine surgery.