A comparison of CT/discography, pain response and radiographic disc height.

CT/discograms of 107 low-back patients were classified by annular degeneration, annular disruption, and pain response. These parameters were compared with the heights of the corresponding discs. Disc height correlated significantly with degenerative annular changes. Comparison of the painless and exact reproduction groups at the L5-S1 level showed a significant increase in exact pain reproduction in narrow discs compared with normal discs. Discs demonstrating slight degenerative changes were often painful but narrowing was detected only when degeneration increased to moderate or severe levels. Some severely degenerated discs were painless and only part of the severe group was narrow. Measuring disc height is a poor method for detecting early, painful degeneration changes.