Cranial thoracic myelopathies (T1-T6 vertebrae): Retrospective evaluation of the signalment, clinical presentation, and, presumptive or final diagnoses in 84 dogs

Abstract

The aim of the study was to describe the signalment, clinical presentation and presumptive or final diagnoses of dogs with cranial thoracic spinal cord lesions identified on advanced imaging. Retrospective evaluation of the databases of three veterinary specialty centres, between 2009 and 2021, was performed to identify dogs with a lesion affecting the cranial thoracic vertebral column (T1-T6 vertebrae) as the primary cause for presenting signs of myelopathy and/or spinal pain. Eighty-four dogs were included in the study, with the majority (n = 76) presenting with a progressive history of over 4-weeks' duration. On neurologic examination, most dogs were ambulatory (n = 64), and the most common neuroanatomic localisation was the T3-L3 spinal cord segments (n = 63). Twelve dogs (14%) showed a short-strided thoracic limb gait on clinical examination. The most common diagnosis was neoplasia (n = 33), followed by anomalies (n = 22, including vertebral body malformations in 14 dogs) and degenerative disorders (n = 16, with intervertebral disc protrusion diagnosed in 9 dogs). The most common vertebrae affected were T3 and T5. Most dogs with degenerative conditions showed asymmetric clinical signs, and the majority of dogs with neoplasia showed signs of spinal hyperaesthesia on examination. The findings of this study describe the clinical signs and presumptive or final diagnoses associated with lesions affecting the cranial thoracic spinal cord. When combined with the signalment and clinical history, this information can assist in both the recognition of and problem-based approach to these cases.

Demographics, clinical findings and diagnoses of cranial thoracic myelopathies (T1–T6 vertebrae) in cats

“… 2 Regarding the observation of a ‘two-engine gait’, this was observed in only 1/21 cats, in contrast to the 14% of dogs with a lesion in this area reported by a similar study. 17 Although the sample size is small, this suggests that this clinical sign may either be more difficult to recognise in cats, or may not be a common feature of cranial thoracic vertebral column disorders in cats, perhaps reflecting their lighter body weight or other anatomical differences between species. Related to this, the only cat with a ‘two-engine gait’ presented a solitary lesion at the level of the T1 vertebral body.…”

“…1,2,4 Intervertebral disc herniation is reported to be more common in the lumbar region of cats, 5,6 and reports of disorders affecting the thoracic spinal cord in cats are currently limited to case reports and small case series, such as articular process hypertrophy resulting in vertebral canal stenosis, [7][8][9][10] vertebral hyperostosis, 11 intervertebral disc protrusion (IVDP), 12,13 subarachnoid diverticulum 14 and different types of neoplasia. 15,16 A recent publication described the signalment, clinical presentation and differential diagnoses of cranial thoracic myelopathies (between the T1 and T6 vertebrae) in dogs; 17 however, to the authors' knowledge, there is still a lack of information on myelopathies affecting this region in cats. This information could be useful, as it may allow a clinician to advise the owner of an affected cat regarding the most likely differential diagnoses after suspicion of a lesion in this region, which could then be used to formulate a focused and appropriate diagnostic plan.…”

“…A recent publication described the signalment, clinical presentation and differential diagnoses of cranial thoracic myelopathies (between the T1 and T6 vertebrae) in dogs; 17 however, to the authors’ knowledge, there is still a lack of information on myelopathies affecting this region in cats. This information could be useful, as it may allow a clinician to advise the owner of an affected cat regarding the most likely differential diagnoses after suspicion of a lesion in this region, which could then be used to formulate a focused and appropriate diagnostic plan.…”

Possible case of prefixed brachial plexus in a dog with a caudal cervical intervertebral disc extrusion

“…2 Brachial plexus variations have been reported in several species, although the literature is very sparce for dogs. 3,7,9,13 In human medicine, the prevalence of prefixed and postfixed brachial plexus is estimated to be 10%-65% and 4%-7.5%, respectively. [6][7][8][9] Abnormalities of the brachial plexus may be associated with concurrent anatomical alterations of the nearby structures; examples include variations in the composition and subdivision of the trunks, divisions and cords that form the branches of brachial plexus, changes in the relationship between the brachial plexus and the axillary artery or variation in the number of axillary arteries and veins.…”

“…Brachial plexus variations have been reported in several species, although the literature is very sparce for dogs 3,7,9,13 . In human medicine, the prevalence of prefixed and postfixed brachial plexus is estimated to be 10%–65% and 4%–7.5%, respectively 6–9 .…”