Evaluation of radiography as a screening method for detection and characterisation of congenital vertebral malformations in dogs

Abstract

Congenital vertebral malformations (CVM) are common in brachycephalic 'screw-tailed' dogs; they can be associated with neurological deficits and a genetic predisposition has been suggested. The purpose of this study was to evaluate radiography as a screening method for congenital thoracic vertebral malformations in brachycephalic 'screw-tailed' dogs by comparing it with CT. Forty-nine dogs that had both radiographic and CT evaluations of the thoracic vertebral column were included. Three observers retrospectively reviewed the images independently to detect CVMs. When identified, they were classified according to a previously published radiographic classification scheme. A CT consensus was then reached. All observers identified significantly more affected vertebrae when evaluating orthogonal radiographic views compared with lateral views alone; and more affected vertebrae with the CT consensus compared with orthogonal radiographic views. Given the high number of CVMs per dog, the number of dogs classified as being CVM free was not significantly different between CT and radiography. Significantly more midline closure defects were also identified with CT compared with radiography. Malformations classified as symmetrical or ventral hypoplasias on radiography were frequently classified as ventral and medial aplasias on CT images. Our results support that CT is better than radiography for the classification of CVMs and this will be important when further evidence of which are the most clinically relevant CVMs is identified. These findings are of particular importance for designing screening schemes of CVMs that could help selective breeding programmes based on phenotype and future studies.

Congenital malformations of the lumbosacral vertebral column are common in neurologically normal French Bulldogs, English Bulldogs, and Pugs, with breed‐specific differences

“…13 Although it is possible that the three assessed brachycephalic breeds are predisposed for lumbosacral spinal bifida, it is likely that the use of cross-sectional imaging has contributed to the high prevalence in this study as previously suggested. 35 Analysis of previous reports suggests a predisposition of English Bulldogs for lumbosacral spina bifida, 14 which could not be confirmed in our study. It should, however, be emphasized that previous reports have focused on clinically affected dogs, while this study included only apparently neurologically normal dogs.…”

“…Spina bifida was a rather uncommon finding in this study but was still markedly higher than previously suggested with 0.007% independent of the breed . Although it is possible that the three assessed brachycephalic breeds are predisposed for lumbosacral spinal bifida, it is likely that the use of cross‐sectional imaging has contributed to the high prevalence in this study as previously suggested . Analysis of previous reports suggests a predisposition of English Bulldogs for lumbosacral spina bifida, which could not be confirmed in our study.…”

Vertebral Formulae and Congenital Vertebral Anomalies in Guinea Pigs: A Retrospective Radiographic Study

“…The prevalence of CTV is relatively low in the adult animal and human populations. Prevalence in dogs is 2.1-14%, where pugs seem to be overrepresented, in cats 1%, and in the human population 0.04-6.2% [27,35]. CTV was also detected with a higher incidence in fossil Pleistocene rhinoceroses and mammoths [36,37].…”

“…Low variability of cervical vertebrae number in the adult population is usually explained by the Hox gen pleiotropic function. Numerical variants in the cervical vertebral column increase risk for prenatal mortality and neonatal cancer [7,27].…”

Comparison of signalment and computed tomography findings in French Bulldogs, Pugs, and English Bulldogs with and without clinical signs associated with thoracic hemivertebra

“…Although the terminology and classification are debated, hemivertebra are considered a common type of congenital vertebral body malformation . Thoracic hemivertebrae occur commonly in clinically normal small breed brachycephalic dogs and therefore should be considered incidental imaging findings in the majority of dogs in which they are identified . Hemivertebrae can be associated with an abnormal dorsal (ie, kyphosis) or lateral (ie, scoliosis) curvature of the vertebral column and have the potential to alter spinal biomechanics, contribute to degenerative spinal conditions, or result directly in clinical signs of spinal cord dysfunction .…”