Identification of Cervical Vertebral Column Variations and Pathology in The Adult Ataxic Horse. A Computed Tomography and Radiographic Evaluation.

Abstract

Summary Objective: Anatomy and disorders like osteoarthritis, cervical vertebral stenosis and intervertebral disc degeneration of the equine cervical vertebral column analyzed with Computed Tomography (CT) has received little attention in literature. The aim of this study is to get a better understanding of the equine cervical vertebral column, comparing radiography and CT as different imaging techniques. Methods: Nineteen radiographic studies and twenty-six CT scans were analyzed for the presence of osteoarthritis. In CT, osteoarthritis was defined by sclerosis, subchondral osteolysis and osteophyte formation. Moreover, intravertebral sagittal ratio and intervertebral disc space was measured in both imaging modalities, of which the results were compared. In sub analysis of intervertebral disc space, the impact of neck position, measuring side and age were compared. Results: The quantity of osteoarthritis was higher in CT (94,8%) than in radiographic images (29,5%). The intravertebral sagittal ratios (ISR) in radiographic images (0.54-0.57 ± 0.059-0.082) and CT (0.52-0.56 ± 0.046-0.089) did not significantly differ from each other (t(38) = 0.4518, p = 0.654), 95% CI [-0.0348, 0.0548]. The intervertebral disc spaces width (IDS) in radiographic images were dorsally smaller (4,75-6,57 ± 0,75-1,16) than in CT images (5,41-7,24 ± 0,79-1,90), but the ventral results of radiography (4,28-5,33 ± 0,60-0,77) and CT (3,64-5,45 ± 0,57–1,57) were comparable. The IDS in neutral positions are larger (4,14mm – 8,1mm) than the IDS width in flexed positions (3,52mm – 6,68mm). The widest IDS in both positions and both sides of measuring was analyzed at C6-C7 articulations. There was a difference in IDS results of location of measuring (dorsal side 5,72mm – 8,1mm; ventral side 3,52mm – 6,56mm), but not with age (e.g. cervical column in flexed position: 16 years old horse with the smallest IDS width (4,25mm) and another 16 years old horse with the largest IDS width (6,82 mm)). Conclusion: CT showed more osteoarthritic changes compared to radiography, therefore CT could be more superior to get detailed information about the equine cervical vertebral column and its pathology. Moreover, the ISR could also be used in detecting cervical vertebral stenosis in CT images. The IDS results were the highest in CT images, at neutral cervical column positions, at dorsal measuring sides, but there was no difference with age.