Spine
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A retrospective review of a prospective database. ⋯ 4.
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Retrospective matched pair cohort study using prospectively collected registry data. ⋯ 3.
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A genetic association study. ⋯ 3.
A retrospective review of a prospective database. ⋯ 4.
Retrospective matched pair cohort study using prospectively collected registry data. ⋯ 3.
A genetic association study. ⋯ 3.