Spine
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Retrospective analysis of prospectively collected data. ⋯ 2.
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Retrospective matched cohort analysis. ⋯ 3.
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Retrospective database review. ⋯ 3.
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Observational study. ⋯ 3.
Retrospective analysis of prospectively collected data. ⋯ 2.
Retrospective matched cohort analysis. ⋯ 3.
Retrospective database review. ⋯ 3.
Observational study. ⋯ 3.