Disc degeneration and angular movement of the lumbar spine: comparative study using plain and flexion-extension radiography and discography.

A study was made of the association between disc degeneration observed in plain radiographs, in discograms (Adams' classification), and instability expressed as abnormal angular movement of lumbar vertebrae. The series included 169 discs in 77 consecutive patients (42 men, 35 women) whose mean age was 34 (range 16-46) years. Discography was more sensitive than plain radiography in the diagnosis of disc degeneration was more common in men than in women (Chi square test, chi 2 = 9.88, p less than 0.05). An increase in disc degeneration was observed in lower lumbar segments (Chi square test, chi 2 = 48.63 p less than 0.001). However, no association between abnormal angular movement and discogram type was observed (Chi square test, chi 2 = 2.63, p less than 0.05). It seems that disc degeneration seldom results in abnormal angular movement and instability of the lumbar spine. Therefore, flexion-extension radiography may only have limited diagnostic value.