Magnetic resonance imaging of articular process joint geometry and intervertebral disk degeneration in the caudal lumbar spine (L5-S1) of dogs with clinical signs of cauda equina compression.

The geometry of the lumbosacral region has been suspected to play a role in the development of degenerative lumbosacral stenosis in the dog. In this study, 50 dogs (21 German Shepherd dogs and 29 dogs of other breeds) with clinical signs of cauda equina compression were studied by magnetic resonance (MR) imaging. The orientation of the articular process joints in the L5-S1 region and the angle difference between two adjacent motion segments were calculated. Intervertebral disc degeneration of the same region was identified and classified in four stages. A positive association between MR-imaging stage and articular process joint angle difference in the transverse plane was found in the two groups of animals. German Shepherd dogs and dogs of other breeds had different geometry of the lumbosacral region with different articular process joint angles in the transverse plane and statistically different stages of disc degeneration.