The use of in vivo lumbar discography to assess the clinical significance of the position of the intercrestal line.

An investigation of the clinical relevance of the location of the intercrestal line in relation to the pattern of disc degeneration in the lower lumbar spine is presented. An analysis of the discograms from 89 symptomatic patients has demonstrated a difference in the incidence of disc degeneration in the L4-5 and L5-S1 disc spaces dependent on the position of the intercrestal line. This difference supports the hypothesis that additional protection will be given to those L5-S1 discs with which high intercrestal lines are associated as compared to those associated with intercrestal lines lying lower down the spine. A corollary of this hypothesis is that for any individual there is an increased likelihood that the L4-5 disc space will undergo degeneration from the influence of normal mechanical stresses before the L5-S1 disc space if the intercrestal line lies comparatively high up the spine.