Radiological variables
foraminal stenosis
The inter- and intra-observer agreement analysis regarding the preoperative MRI examinations is reported in a previous study [0 = fat surrounding nerve in all directions1 = fat lost only horizontally or vertically2 = fat lost both horizontally or vertically3 = fat lost both horizontally or vertically with morphological changes the nerve rootWe dichotomized the radiological scores into none to moderate changes (Lee 0–1) or severe changes (Lee 2–3) in accordance with earlier publications [A decreased disk height is likely associated with the development of foraminal stenosis [Previous studies have indicated an association between Schizas score and DSCA and outcome. Therefore, these parameters were included in the analysis as covariates, although such associations are not suggested generally [A thorough discussion of the dichotomization of investigated covariates (Schizas, DSCA, and Pfirrmann) is presented in earlier publications [