"progressive slip > 1 grade"
"Spondylolisthesis is from the Ancient Greek σπονδύλους (spondylous) meaning vertebra and ολίσθηση (olisthesis) meaning slippage 6. Carl von Rokitansky, (1804-1878), an Austrian pathologist, was the first to describe spondylolisthesis in 1839 8."
Expected headings
"Classification"