Spine
-
A prospective clinical study. ⋯ 3.
-
Validation of 2 self-report questionnaires. ⋯ 3.
-
Retrospective national database analysis. ⋯ 3.
-
Retrospective cohort study. ⋯ 2.
-
Retrospective study of an administrative database. ⋯ 4.