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

ABSTRACT

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.