A forward slippage of one vertebra on the next one below is called spondylolisthesis (spondyl: vertebra; olisthesis: slippage). This is either Low grade (< 50%) or high grade (> 50%). It can occur due to an underlying pars defect, though may be linked to facet degenerative changes. Secondary disc degeneration is seen in advanced cases.

Treatments range from pain relief, physiotherapy to surgery to fuse thesegments.