Spine
-
Retrospective matched cohort analysis. ⋯ 3.
-
This is a retrospective cohort study. ⋯ 4.
-
Immunohistochemical and real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. ⋯ N/A.
-
Retrospective analysis. ⋯ 3.
-
Cross-sectional survey. ⋯ 4.