Spine
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Cross-sectional study. ⋯ 3.
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Multicenter Study
Five-year Results of a Randomized Controlled Trial for Lumbar Artificial Discs in Single-level Degenerative Disc Disease.
A prospective, multicenter, randomized, controlled, investigational device exemption (IDE) noninferiority trial. ⋯ 2.
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Retrospective cohort study. ⋯ 3.
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Retrospective study with prospective radiographic data collection. ⋯ 3.