Evaluation of the influence of kyphosis and scoliosis on intervertebral disc extrusion in French bulldogs

Abstract

BackgroundAlthough thoracic vertebral malformations with kyphosis and scoliosis are often considered incidental findings on diagnostic imaging studies of screw-tailed brachycephalic breeds, they have been suggested to interfere with spinal biomechanics and intervertebral disc degeneration. It is however unknown if an abnormal spinal curvature also predisposes dogs to develop clinically relevant intervertebral disc herniations. The aim of this study was to evaluate if the occurrence of thoracic vertebral malformations, kyphosis or scoliosis would be associated with a higher prevalence of cervical or thoracolumbar intervertebral disc extrusion in French bulldogs.ResultsFrench bulldogs that underwent computed tomography for reasons unrelated to spinal disease (n = 101), and French bulldogs with thoracolumbar (n = 47) or cervical intervertebral disc extrusion (n = 30) that underwent magnetic resonance imaging were included. There was a significant association between the presence of kyphosis and the occurrence of intervertebral disc extrusion, particularly in the thoracolumbar region. Dogs with kyphosis were at nearly a two times increased odds of being affected by intervertebral disc extrusion than those without kyphosis [(OR = 1.98 (95% CI: 1.04–3.78)]. There was also an association between the presence of scoliosis and the anatomical distribution of intervertebral disc extrusions, with dogs with scoliosis more likely to have more caudal lumbar intervertebral disc extrusions. Presence of scoliosis was not associated with an increased odds of being affected by intervertebral disc extrusion.ConclusionsAlthough thoracic vertebral malformations with kyphosis only rarely cause spinal cord dysfunction in itself, French bulldogs with kyphosis appear to be at higher risk to develop thoracolumbar intervertebral disc extrusion.Electronic supplementary materialThe online version of this article (doi: 10.1186/s12917-017-1316-9) contains supplementary material, which is available to authorized users.

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

“…It needs to be considered that the included Pugs were significantly older than the two other breeds and that there is a chance that a group of age‐matched Pugs would show a lower prevalence of degenerative lumbosacral changes. The demonstrated association between lumbosacral hemivertebrae and intervertebral disc herniation is in agreement with previous studies assessing the association between thoracic hemivertebra and intervertebral disc degeneration and herniation . Vertebral body malformations and especially associated kyphosis are suggested to change spinal biomechanics that can lead to premature degeneration of adjacent intervertebral discs and a higher prevalence and different anatomical distribution of thoracolumbar intervertebral disc extrusion .…”

“…The demonstrated association between lumbosacral hemivertebrae and intervertebral disc herniation is in agreement with previous studies assessing the association between thoracic hemivertebra and intervertebral disc degeneration and herniation. 11,31 Vertebral body malformations and especially associated kyphosis are suggested to change spinal biomechanics that can lead to premature degeneration of adjacent intervertebral discs and a higher prevalence and different anatomical distribution of thoracolumbar intervertebral disc extrusion. 4,11,31 Our results seem to confirm that not only thoracic but also lumbosacral hemivertebrae are common in French and English Bulldogs but not in Pugs.…”

“…11,31 Vertebral body malformations and especially associated kyphosis are suggested to change spinal biomechanics that can lead to premature degeneration of adjacent intervertebral discs and a higher prevalence and different anatomical distribution of thoracolumbar intervertebral disc extrusion. 4,11,31 Our results seem to confirm that not only thoracic but also lumbosacral hemivertebrae are common in French and English Bulldogs but not in Pugs. 10 Furthermore, our data showed lumbosacral hemivertebrae were associated with a higher degree of tail malformation, whereas…”

Demography and disorders of the French Bulldog population under primary veterinary care in the UK in 2013

“…French Bulldogs are reported as predisposed to health disorders including brachycephalic obstructive airway syndrome (BOAS) [ 7 , 9 – 11 ], dystocia [ 12 ], corneal ulceration [ 8 , 13 ], patellar luxation [ 14 ] and a range of spinal diseases including type I intervertebral disk herniation [ 15 ], spinal disease associated with vertebral malformations [ 16 , 17 ] and spinal arachnoid diverticulum [ 15 ]. It is worth noting that many of these reported predispositions increase in prevalence as dogs age and therefore analyses of younger populations may artifactually appear to show reduced prevalence compared with more mature populations.…”

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

“…Although these findings suggest that the occurrence of thoracic hemivertebra in Pugs should be considered of greater clinical importance, it is possible that hemivertebra in other “screw‐tailed” brachycephalic breeds should not be considered a benign incidental finding on diagnostic imaging studies. Hemivertebra with kyphosis has been suggested to alter spinal biomechanics, which could accelerate or contribute to the development of degenerative changes along the vertebral column, including intervertebral disk degeneration and herniation …”