Lumbosacral transitional vertebra (LTV) is vertebrae at the lumbosacral junction with lumbar and sacral characteristics. The purpose of this study was to assess the prevalence of LTV in clinically inconspicuous dogs and in dogs with cauda equina compression syndrome (CES).

The prevalence of LTV was assessed on ventrodorsal pelvic radiographs. Two groups of dogs were evaluated. The reference group consisted of 4000 pure breed dogs routinely examined for canine hip dysplasia. The CES group consisted of 92 dogs with cauda equina syndrome. The risk of LTV, breed, age, and gender on CES occurrence was calculated using a logistic regression analysis.

In the reference group LTV-prevalence was 3.5 % ranging from 0.0 % to 19.2 % depending on the breed. LTV was significantly more common in German Shepherd dogs and in Greater Swiss Mountain dogs than in all other breeds combined. No gender difference was noted.

In the CES group LTV-prevalence was 16.3% or nearly five fold increased over the reference group. CES symptoms occurred at a mean age of 6.4 years (SD 3.3 years) in dogs without LTV and at a mean age of 4.8 years (SD 2.8 years) in dogs with LTV.

The logistic regression analysis revealed that:

 LTV-dogs had an 8 fold higher risk for CES than dogs without LTV.

 German Shepherd dogs had an 8 fold higher risk for CES than other common breeds.

 Male dogs had a 2 fold higher risk for CES.

 Dogs with LTV tended to develop CES 1 to 2 years earlier than those without LTV.

As a genetic predisposition for LTV is suspected, affected dogs are not recommended for breeding. Costly and time consuming training is not recommended for German Shepherd dogs with LTV since both breed and LTV predispose for CES, and CES-dogs show reduced performance or early drop out.