Lumbosacral endplate contour defect is frequently observed concurrent with other lumbosacral abnormalities on spinal CT of French Bulldogs.

Lumbosacral osteochondrosis has been previously described in large breed dogs with variable clinical signs. Its CT features are a contour defect at the dorsal aspect of either vertebral endplate, commonly with an adjacent fragment. Descriptions of this condition have not been previously published in an increasingly popular breed, French Bulldogs. Aims of this retrospective, descriptive, single center study were to evaluate CT lumbosacral abnormalities and the frequency of lumbosacral endplate contour defect in a large sample of French Bulldogs. The presence and location of lumbosacral endplate contour defect and the presence of a concurrent osseous fragment were recorded. Other abnormal CT findings such as L7-S1 disc herniation, cauda equina nerve roots compression or thickening, disc mineralization, endplate sclerosis, spondylosis deformans, S1 articular processes hypertrophy, transitional vertebrae, hemivertebrae, spina bifida, and block vertebrae were recorded. Lumbosacral CT abnormalities were present in 91.8% of dogs (168/183). The most common abnormality was an L7-S1 dorsal disc herniation (77.4%, 130/168). Among dogs with lumbosacral abnormalities, the frequency of a lumbosacral endplate contour defect was 47% (79/168). It mostly involved L7 (78.5%, 62/79) at its dorsolateral aspect (61.3%, 38/62). A mineralized fragment was identified in 62% of the defects (49/79). Endplate contour defects were most frequently seen with a concurrent disc herniation (93.7%, 74/79) causing nerve root compression in 63.3% (50/79) and with sclerosis (65.8%, 52/79). There was no definitive evidence of a relationship with clinical presentation in this sample of French Bulldogs; therefore, this finding should be interpreted with caution. The etiology remains unclear.