Baseline data
This study included 230 men and 207 women with mean age 66.8 (SD 8.3), in total 437 patients. However, only 414 of the patients had MRIs with adequate visualization of the foraminal canal. The number of patients not returning complete PROMS at follow-up was 46 (11%) including 29 (7%) patients with total dropout. The distribution of index levels was as follows: 24 patients at L2–L3, 146 patients at L3–L4, and 245 patients at L4–L5. The part of the cohort labeled with Lee grades 2–3 presented a higher portion of females (67% vs 47%), more smokers (25% vs 21%), and less patients with higher education (0% vs 29%) when compared to the patients labeled with Lee grades 0–1. Patient characteristics are presented in Table Baseline data. Key parameters of the NORDSTEN-SST cohort