Relationship between breed, hemivertebra subtype, and kyphosis in apparently neurologically normal French Bulldogs, English Bulldogs, and Pugs.

OBJECTIVE To investigate whether hemivertebra subtype as determined via CT was associated with breed and Cobb angle (a measure of the degree of spinal curvature) in apparently neurologically normal French Bulldogs, English Bulldogs, and Pugs. ANIMALS Client-owned French Bulldogs (n = 58), English Bulldogs (30), and Pugs (12) with thoracic hemivertebrae that underwent CT for reasons unrelated to spinal disease. PROCEDURES CT scans of each dog were evaluated, and hemivertebrae were categorized by subtype (ventral aplasia, ventral hypoplasia, lateral aplasia, lateral hypoplasia, ventrolateral aplasia, ventrolateral hypoplasia, ventral and median aplasia, ventral and median hypoplasia, and symmetric hypoplasia). The Cobb angle was measured, and kyphosis was defined as a Cobb angle > 10°. Results were compared among breeds. RESULTS 243 hemivertebrae were identified in the French Bulldog group, 100 in the English Bulldog group, and 19 in the Pug group. Breed was significantly associated with hemivertebra subtype. Pugs were more likely than French and English Bulldogs to have ventral hypoplasia and less likely to have ventral and median hypoplasia. English Bulldogs were more likely than French Bulldogs to have ventral and median hypoplasia. Compared with other hemivertebra subtypes, ventral hypoplasia was associated with a greater Cobb angle and a higher likelihood of kyphosis. Pugs were more likely than the other 2 breeds to have kyphosis. CONCLUSIONS AND CLINICAL RELEVANCE Pugs had a different spectrum of hemivertebra subtypes than French and English Bulldogs in this study. Additional research is necessary to evaluate the clinical relevance of this finding.