Radiological abnormalities of the cervicothoracic vertebrae in Warmblood horses with primary neck-related clinical signs versus controls.

Radiological observations at the cervicothoracic junction in horses with or without related clinical signs have not been comprehensively described. The aim was to evaluate the seventh cervical (C7) to second thoracic (T2) vertebrae in horses with neck-related clinical signs (neck pain and/or stiffness, neck-related forelimb lameness, or general proprioceptive [spinal] ataxia) and control horses. This prospective analytical cross-sectional study included 127 control horses and 96 cases, examined using standardized clinical and radiological protocols. Univariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) to identify factors associated with radiological abnormalities. Severe modeling of the articular processes at C7-T1 was more likely in cases compared with controls, OR, 4.25; CI, 1.04-17.36; P = .04. Cases were more likely to have spondylolisthesis at C7-T1 than controls, OR, 3.61; CI, 1.75-7.44; P < .001. There was a lack of uniformity of disc space width at C6-C7, despite normal alignment of the vertebrae, in five (5.2%) cases and no control horses. Discospondylosis was seen in 9 (9.4%) horses at C7-T1 and 10 of 64 (15.6%) at T1-T2. The sagittal ratio for T1 was smaller for horses with neck-related forelimb lameness (P < .0002), neck pain/ stiffness (P = .04), or neurological cases (P < .001) than controls. The prevalence of radiological abnormalities at C7-T1 and T1-T2 highlights the importance of careful evaluation of the cervicothoracic junction in horses with neck-related signs.