Values derived from patient reported outcomes in spine surgery: a systematic review of the minimal clinically important difference, substantial clinical benefit, and patient acceptable symptom state. - Issa TZ; Lee Y; Henry TW; Trenchfield D; Schroeder GD; Vaccaro AR; Kepler CK (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, 2023)