Equine intervertebral disk disease: A case report

Intervertebral disk disease is common in humans and dogs but is rarely reported in horses. In this case report, we describe an 11-year-old American Saddlebred gelding with a 2-month history of pain and progressive neurological abnormalities (ataxia, conscious proprioceptive deficits involving all four limbs, toe dragging, and restricted neck flexion) while being worked as a Saddleseat show horse. Radiographs of the cervical spine showed a loss of the intervertebral disk space at C₆-C₇. At necropsy, nearly complete loss of the intervertebral disk at C₆-C₇ was seen, with marked eburnation and subchondral sclerosis of the adjacent vertebral endplates that were confirmed by histopathology. Many of the marrow spaces of the affected vertebral bodies were filled with cartilage and others contained variable amounts of fibrous connective tissue (myelofibrosis). To our knowledge, these pathological lesions are rarely reported in the literature and appear to represent a chronic, end-stage phase of cervical vertebral stenosis.