Spine
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A case-control study. ⋯ 2.
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A retrospective review of the Statewide Planning and Research Cooperative System database of the New York State. ⋯ 3.
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Case-only study. ⋯ 4.
A case-control study. ⋯ 2.
A retrospective review of the Statewide Planning and Research Cooperative System database of the New York State. ⋯ 3.
Case-only study. ⋯ 4.