Association of neurologic signs with high-field MRI findings in 100 dogs with osseous-associated cervical spondylomyelopathy.

Although osseous-associated cervical spondylomyelopathy (OA-CSM) findings have been well described using magnetic resonance imaging (MRI), there are no large-scale published studies on the associations between dog size, age, high-field MRI and neurologic findings. Using a retrospective, observational study design, we aimed to investigate an association between neurologic and high-field MRI characteristics in OA-CSM. Records were reviewed for dogs diagnosed with OA-CSM using high-field MRI. One-hundred dogs were included: 73/100 (73%) were giant breeds, 27/100 (27%) large breeds. Mean and median ages were, respectively, 3.1 and 2 years (0.3-9.75 years), with 2.6 and 2 years for giant-breed; and 4.4 and 4 years for large-breed dogs. The majority of dogs were male (75%) with chronic presentation (89%), more than one site of spinal cord compression (78%) and foraminal stenosis (91%). Dogs with multiples sites of spinal cord compression were more likely to have severe spinal cord compression (p < 0.001), severe foraminal stenosis (p < 0.001) and ligamentum flavum/soft tissue proliferation (p = 0.03) than those with a single compressive site. There was a weak correlation between neurologic grade and severity of spinal cord compression (r = 0.27; p = 0.007), number of affected sites (r = 0.24; p = 0.0183) and spinal cord T2W hyperintensity (r = 0.24; p = 0.0152). Intervertebral disc degeneration was seen in 80% of dogs. Age did not appear to have a prominent role in the manifestation of OA-CSM. This study showed that OA-CSM affects a sizeable proportion of young large-breed, in addition to giant-breed dogs.

Magnetic resonance imaging and neurological findings in dogs with disc-associated cervical spondylomyelopathy: a case series.

BACKGROUND: Canine cervical spondylomyelopathy can be separated into osseous and disc-associated (DA-CSM) forms. Our aim was to describe the magnetic resonance imaging (using a high-field scanner) and neurological findings in dogs with DA-CSM and investigate a relationship between these findings. RESULTS: Sixty-three dogs were included: 60/63 (95 %) were large breeds, with Doberman Pinschers and males over-represented (70 %). Mean and median age at the time of diagnosis was 7.25 and 7.2 years (range 0.41-12 years). Chronic signs were noted in 52/63 (83 %) dogs, with proprioceptive ataxia the most common. Main site of spinal cord compression was commonly C6-7 or C5-6. Thirty-six (57 %) dogs had various sites of spinal cord compression. Most dogs younger than 6 years of age had a single affected site. Foraminal stenosis was present in 51/63 dogs (81 %). T2-weighted hyperintensity was present in 40/63 dogs (63 %). 88 % of the articular processes showed degenerative changes, which correlated strongly with intervertebral disc degeneration. Ligamentum flavum hypertrophy was seen in 38 % of dogs. No correlation was observed between neurologic signs and number of affected sites. A moderate positive correlation was observed between severity of spinal cord compression and neurologic grade (r 0.48; p < 0.001). CONCLUSIONS: DA-CSM was predominantly observed in older, male Dobermans, with lesions located in the caudal cervical vertebral region. It was also seen in dogs 3 years of age or even younger (8 %). Single compressive lesions were more common in dogs younger than 6 years of age. Many dogs had concomitant changes (e.g.: ligamentum flavum hypertrophy and foraminal stenosis). Most dogs with ligamentum flavum hypertrophy were 6 years or older. A positive correlation was observed between severity of spinal cord compression and neurologic grade, but multilevel compression was not associated with more severe neurologic signs. A very high percentage of dogs had articular process degenerative changes. Possible biomechanical or genetic relationships between degenerative changes in articular processes, ligamentum flavum, and intervertebral discs warrants further investigation.