The effect of kyphoscoliosis on intervertebral disc degeneration in dogs.

In people, abnormalities in vertebral column conformation, such as kyphoscoliosis, induce degenerative changes in adjacent intervertebral disc (IVD) structure and composition. It was hypothesised that canine IVDs adjacent to a vertebral malformation undergo early degeneration. In a blinded retrospective study, thoracic IVD degeneration was evaluated in 14 dogs on magnetic resonance images using Pfirrmann's grade. IVDs adjacent to a vertebral malformation had higher grades of degeneration than non-adjacent IVDs (P < 0.0001). There was an age-dependency, with dogs between 1 and 4 years showing higher grade of degeneration in adjacent than non-adjacent IVDs (P < 0.0001). Conversely, in older dogs, all IVDs - including the non-adjacents - showed degenerative signs, possibly due to normal aging. These results suggest that congenital vertebral malformation results in early degeneration of adjacent IVDs.