Thoracic Kyphosis Associated with Hemivertebra

OBJECTIVE: To radiographically assess the influence of thoracic hemivertebra on kyphosis and neurologic status in 45 dogs. STUDY DESIGN: Case series. ANIMALS: French Bulldogs without neurologic signs (n = 41) and 4 dogs with compressive spinal cord disease associated with hemivertebra. METHODS: Thoracic spinal radiographs were divided into 3 groups: 1 = dogs with no hemivertebra, 2 = dogs with hemivertebra but no associated neurologic signs, and 3 = dogs with hemivertebra associated with clinical signs. Vertebral canal height, vertebral column angle, and the step between 2 adjacent vertebrae were measured in each group. RESULTS: Vertebral canal height was not significantly different in the 3 groups; however, mean vertebral column angle was significantly (P < .001) different between groups 1 (178°) and 2 (169°), and group 3 (133°). Median cranial step was significantly different between groups (P < .001): 0 mm (group 1), 0.3 mm (group 2), 3 mm (group 3). CONCLUSIONS: Vertebral canal height does not differ between normal dogs and dogs with thoracic hemivertebra. There is an important association between neurologic signs and kyphosis and subluxation. CLINICAL RELEVANCE: Vertebral realignment without vertebral canal opening could lead to spinal cord decompression in dogs affected by thoracic hemivertebra.