Upper thoracic disc disease (T1-T9) in large-breed dogs

The purpose of this study was to identify large-breed dogs with intervertebral disc disease (IVDD) in the upper thoracic region (thoracic vertebrae 1-9 [T1-T9]). Medical records of all dogs that were diagnosed with IVDD on MRI between February 2008 and September 2011 were reviewed. Of 723 dogs diagnosed with IVDD based on MRI, 527 (72.9%) were small-breed dogs. There were 21 (10.7%) large-breed dogs with IVDD in the T1-T9 region, whereas no small-breed dogs were identified with lesions in that region. The most common upper thoracic lesion sites were T2-T3 (33.3%) and T4-T5 (25.9%). The majority of dogs with T1-T9 lesions were German shepherd dogs (52.4%). Larger, older dogs were more likely to have T1-T9 lesions and more likely to have multiple regions with IVDD, in particular German shepherd dogs (35.1%). Dogs with T1-T9 IVDD were more likely to have IVDD in another region (66.7%). All large-breed dogs presenting with T3-L3 myelopathy should have diagnostic imaging performed of their entire thoracic and lumbar spine.