Cervical Vertebral Lesions in Equine Stenotic Myelopathy

Abstract

Skeletal lesions in the articular processes of cervical vertebrae C2 to C7 were compared between Thoroughbred horses with cervical stenotic myelopathy (17 males, 2 females; age, 6-50 months) and controls (6 males, 3 females; age, 9-67 months). Lesions identified by magnetic resonance imaging occurred with an increased frequency and severity in diseased horses and were not limited to sites of spinal cord compression. Lesions involved both the articular cartilage and trabecular bone and were further characterized using micro-computed tomography and histopathology. The most common histologic lesions included osteochondrosis, osseous cyst-like structures, fibrous tissue replacement of trabecular bone, retained cartilage matrix spicules, and osteosclerosis. Osseous cyst-like structures were interpreted to be true bone cysts given they were a closed cavity with a cellular lining that separated the cyst from surrounding bone. This is the first report of bone cysts in the cervical articular processes of horses with cervical stenotic myelopathy. The morphology and distribution of the lesions provide additional support for the previously proposed pathogenesis that developmental abnormalities with likely secondary biomechanical influences on the cervical spine contribute to equine cervical stenotic myelopathy.

Arthroscopic treatment for cervical articular process joint osteochondrosis in a Thoroughbred horse

“…OCD and secondary degenerative joint disease is sometimes associated with cervical stenotic myelopathy: Janes et al . () reported OCD lesions to be significantly more common in horses diagnosed with cervical vertebral malformation (CVM) compared to clinically normal horses, but in other studies, OCD has been inconsistently associated with CVM (Reed et al . ; Stewart et al .…”

“…Pathology of the APJs can cause neck pain, abnormal head carriage and forelimb lameness (Ricardi and Dyson 1993;Van Biervliet 2007;Dyson 2011) and enlarged APJs can cause dorsolateral compression of the spinal cord, contributing to cervical spondylomyelopathy (Moore et al 1994). Osteochondrosis (OCD) of the APJs has been reported (Powers et al 1986;Stewart et al 1991;Trostle et al 1993) and has been confirmed in a small number of horses at postmortem examination (Beck et al 2002;Janes et al 2015).…”

“…; Janes et al . ). Arthroscopic treatment of OCD is widely performed in the joints of the equine appendicular skeleton and procedures such as debridement of abnormal cartilage and removal of OCD fragments are commonplace.…”

Biochemical and biomechanical characterisation of equine cervical facet joint cartilage

“…It is thought that progressive bone changes are responsible for the decreased range of motion, nerve root impingement, lameness and pain associated with facet joint pathology . However, in many cases, these bone changes are a secondary result of a primary cartilage lesion . Therefore, treatment of articular cartilage lesions could preclude the onset of degenerative changes and may alleviate clinical signs associated with facet joint disease.…”

No Bones About It

“…Karikoski et al 9 provide a detailed correlation of endocrinopathic laminitis with clinical, macroscopic, and microscopic findings. Another fine example is the article by Janes et al, 8 in which the cervical spine in young horses with and without spinal cord compression is systematically evaluated using magnetic resonance imaging (MRI), with histological confirmation of identified lesions. Although lesions were observed more frequently in affected horses, their generalized distribution and presence in unaffected horses support an underlying developmental cause for the lesions and clinical signs seen in this disease.…”