Spine
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Cross-sectional study. ⋯ 2.
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A retrospective cohort study at a single institution. ⋯ 3.
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Retrospective cohort comparative study. ⋯ 3.
Cross-sectional study. ⋯ 2.
A retrospective cohort study at a single institution. ⋯ 3.
Retrospective cohort comparative study. ⋯ 3.