Figure 13

Degenerative pathways of the disco-vertebral complex. ‘Age’ is the average chronological age of the vertebral segments in each cluster, ‘SD’ is the standard deviation and ‘VESC’ is vertebral endplate signal change. The clusters were divided into the following five pathways: (i) Progressive stages of disc degeneration in the lower lumbar levels. (ii) Progressive stages of disc herniations and VESC in the lower lumbar levels. (iii) Progressive endplate changes and disc degeneration at the upper lumbar levels only. (iv) VESC only at either the upper or the lower endplates. (v) Osteophytes at the upper lumbar motion segments.