Spine
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Retrospective review. ⋯ 3.
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Validation of a performance scale. ⋯ 3.
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Retrospective observational and case-control study. ⋯ 4.
Retrospective review. ⋯ 3.
Validation of a performance scale. ⋯ 3.
Retrospective observational and case-control study. ⋯ 4.