Cervical Vertebral Lesions in Equine Stenotic Myelopathy.
Authors: Janes J G, Garrett K S, McQuerry K J, Waddell S, Voor M J, Reed S M, Williams N M, MacLeod J N
Journal: Veterinary pathology
Summary
# Cervical Vertebral Lesions in Equine Stenotic Myelopathy Cervical stenotic myelopathy (CSM) in young Thoroughbreds involves progressive spinal cord compression, yet the underlying skeletal pathology remains incompletely characterised. Janes and colleagues examined cervical vertebrae from 19 affected horses (aged 6–50 months) and 9 controls using magnetic resonance imaging, micro-computed tomography, and histopathology to identify and classify lesions in the articular processes of vertebrae C2 to C7. Diseased horses exhibited significantly increased frequency and severity of skeletal changes compared to controls, with pathology distributed beyond sites of visible spinal cord compression; lesions encompassed osteochondrosis, trabecular bone loss, retained cartilage matrix fragments, and importantly, true bone cysts—a finding previously unreported in equine cervical articular processes. The identification of these diverse developmental and degenerative changes, particularly the osseous cyst-like structures characterised as genuine bone cysts with cellular linings, provides mechanistic insight into how abnormal skeletal maturation coupled with secondary biomechanical stress contributes to progressive myelopathic disease. For practitioners managing young racehorses with ataxia or gait abnormalities, these findings underscore that CSM involves complex skeletal pathology extending beyond simple stenosis, supporting early diagnostic imaging and careful consideration of loading demands during rehabilitation and training protocols.
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Practical Takeaways
- •Cervical stenotic myelopathy involves complex skeletal pathology beyond simple compression; early recognition through imaging may help identify predisposed horses before clinical signs develop.
- •The presence of developmental lesions (osteochondrosis, bone cysts) suggests this condition has roots in growth disturbances, potentially influenced by genetics, nutrition, or growth rate—management of young stock may be preventative.
- •MRI findings of articular process lesions carry diagnostic and prognostic significance even when they don't directly compress the spinal cord.
Key Findings
- •Skeletal lesions in cervical articular processes (C2-C7) occurred with significantly increased frequency and severity in horses with cervical stenotic myelopathy compared to controls.
- •Lesions involved both articular cartilage and trabecular bone, including osteochondrosis, osseous cyst-like structures, fibrous tissue replacement, retained cartilage matrix spicules, and osteosclerosis.
- •True bone cysts were identified in cervical articular processes of affected horses—the first report of this finding in cervical stenotic myelopathy.
- •Lesions were not limited to sites of spinal cord compression, supporting a developmental pathogenesis with secondary biomechanical influences on the cervical spine.