Lumbosacral transitional vertebrae as a predisposing cause of cauda equina syndrome in German shepherd dogs: 161 cases (1987-1990).

The records of 161 German Shepherd Dogs were divided into groups depending on whether there was a radiographic diagnosis of degenerative disk disease (DDD) involving the lumbosacral disk and lumbosacral transitional vertebral segments (TVS) and whether the dogs had cauda equina syndrome (CES). Statistical analysis of the data suggested an association between TVS and CES and an association between DDD and CES. Establishment of confidence intervals revealed the group without either DDD or TVS indicators differed markedly from the other 3 groups of CES relative to the presence of DDD and TVS. There was some overlap in the confidence intervals, but the proportions of CES were higher when DDD and TVS were both evident. This suggests that the important clinical syndrome of CES is at least partially dependent on TVS, which is probably an inherited condition. Because German Shepherd Dogs have a higher frequency of TVS than dogs of other breeds, this partially explains the higher frequency of CES in this breed. Because TVS are probably familial, we suggest the presence of this lesion should be considered in selection of breeding stock. Although it is believed that DDD is partially dependent on the existence of TVS, it is known that DDD can develop in the absence of TVS.