Two-tailed Fisher's exact test (Cochran-Mantel-Haenzel).
Balasubramaniam
Mamtha
M
Fischgrund
Jeffrey S
JS
D003627:Data Interpretation, Statistical; D006801:Humans; D011542:Pseudarthrosis / Q000453:epidemiology*; D013130:Spinal Stenosis / Q000453:epidemiology*; D013168:Spondylolisthesis / Q000453:epidemiology*