Spontaneous regression of extradural intraspinal cysts in a dog: a case report

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.

Long-term clinical and magnetic resonance imaging follow-up of dogs with osseous-associated cervical spondylomyelopathy

BACKGROUND

Osseous-associated cervical spondylomyelopathy (OA-CSM) is a complex disorder with limited long-term survival. The longitudinal progression is currently unknown.

OBJECTIVE

To describe changes on magnetic resonance imaging (MRI) over a 2-year minimum period. We hypothesized that spinal lesions would progress in the majority of dogs.

ANIMALS

Eleven dogs previously diagnosed with OA-CSM were prospectively studied. Nine dogs were treated medically, whereas 2 were treated surgically.

METHODS

Clinical and MRI follow-up were performed with a median time between MRI studies of 30 months (range, 24-54). Morphologic assessment evaluated vertebral canal stenosis, spinal cord compression, foraminal stenosis, and articular processes, among other variables. Morphometric assessment included vertebral canal area, spinal cord area, area of the articular processes, and foraminal height.

RESULTS

On follow-up MRI, the most affected site at the initial examination in medically treated dogs had progressed in 4 of 9 dogs, improved in 4, and was unchanged in 3. Clinically, all dogs except 2 medically treated dogs were unchanged to improve at follow-up. Initially, 50 of 60 (83.3%) intervertebral spaces had vertebral canal stenosis, whereas in the follow-up MRI 82.3% did. Of the sites with stenosis, 45.7% were unchanged, 18.6% improved, and 38.9% worsened. Morphometry identified significant decreases in vertebral canal and spinal cord areas at C4-C5 through C6-C7, and significant progression of articular process irregularities at C3-C4 and C6-C7.

CONCLUSIONS AND CLINICAL IMPORTANCE

This long-term follow-up study of dogs with OA-CSM did not identify clinical or MRI progression of lesions in the majority of dogs.