How reliable are the Core Outcome Measures Index and Global Treatment Outcome as measures of treatment success after surgery for central lumbar spinal canal stenosis? - Nauer S; Porchet F; Kleinstueck FS; Haschtmann D; Burgstaller JM; Fekete TF; Loibl M; Mannion AF (European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2025)