Pennings JS, Khan I, Davidson C, et al. - This study was intended to compare the PROMIS-29 (v2.0) to the neck Disability Index (NDI) and compute a conversion equation. Researchers retrospectively examined prospectively collected data from the cervical module of national spine registry, the Quality Outcomes Database (QOD). For cervical spine surgery patients, the QOD was queried with PROMIS-29 and NDI scores.  The study population consisted of 2,018 patients from 18 US hospitals (mean age=58 years (SD=12)) with 47% female, 88% Caucasian, and 11% had revision surgery. The data imply accurate NDI scores can be derived from PROMIS-29 domains. The results suggest that clinicians who want to move from NDI to PROMIS-29 can use this equation to collect calculated NDI scores when only collecting PROMIS-29. In cervical surgery populations, the findings support the use of PROMIS-29 and underscore the idea that PROMIS-29 domains have the potential to replace disease-specific traditional PROMs.