Spine
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Retrospective study. ⋯ 4.
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Retrospective cross-sectional study. ⋯ 2.
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Retrospective observational cohort study. ⋯ 3.
Retrospective study. ⋯ 4.
Retrospective cross-sectional study. ⋯ 2.
Retrospective observational cohort study. ⋯ 3.