Spine
-
Prospective cross-sectional case-control study design. ⋯ 2.
-
Retrospective. ⋯ 3.
-
Retrospective comparative cohort study. ⋯ 4.
Prospective cross-sectional case-control study design. ⋯ 2.
Retrospective. ⋯ 3.
Retrospective comparative cohort study. ⋯ 4.