Spondylosis deformans and diffuse idiopathic skeletal hyperostosis in dogs: A radiographic study

Abstract

The study involved eight dogs presented with a history of progressive pelvic limb ataxia, paraparesis or paraplegia, spinal hyperesthesia, back pain, and difficulty in walking or climbing stairs. Radiographic examinations were performed on all dogs. Based on clinical and radiographic findings, seven dogs (five males and two females) were diagnosed with spondylosis deformans (SD), while diffuse idiopathic skeletal hyperostosis (DISH) was diagnosed in a 9-yr-old male non-descript dog. Large-breed dogs were more commonly affected. The diagnosis of SD was established using a four-point grading system that assessed the degree of enthesophyte development at each site. In contrast, DISH was identified by the presence of extensive bony outgrowths along the vertebrae, resulting in spinal stiffness and pain. DISH can be differentiated from SD by the location and extent of new bone formation, particularly its involvement of the ventral longitudinal ligament.