Equine intervertebral disc disease with dorsal protrusion and spinal cord compression: A computed tomography, myelography, MRI, and histopathologic case study.

Overview

• This study reports a detailed case of a young horse with spinal cord compression caused by intervertebral disc protrusion in the neck region.
• The diagnosis was confirmed through multiple advanced imaging techniques and postmortem examination, highlighting a rare condition in horses.

Background and Clinical Presentation

• A 3-year-old American Saddlebred gelding showed progressively worsening neurological symptoms including:
  • Tetraparesis (weakness in all four limbs)
  • Ataxia (lack of coordination)
  • Cervical hyperaesthesia (increased sensitivity/pain in the neck area)
• These signs suggested spinal cord involvement, prompting further diagnostic imaging.

Diagnostic Imaging Techniques Used

• Radiographic myelography: X-rays taken after injecting contrast dye into the spinal canal where the nervous tissue resides.
  • Identified spinal cord compression at vertebral levels C6-7 in various neck positions (neutral, extended, flexed).
  • Also noted possible compression at C4-5 during flexed neck position.
• CT myelography: Computed tomography combined with myelography allows detailed cross-sectional views.
  • Confirmed severe narrowing of the vertebral canal (vertebral canal stenosis) specifically at C6-7.
• Magnetic Resonance Imaging (MRI):
  • Postmortem MRI demonstrated severe herniation (protrusion) of the intervertebral disc at C6-7.
  • Detected changes within the spinal cord tissue itself (intramedullary changes), indicating damage caused by compression.

Postmortem Findings and Histopathology

• Macroscopic examination after euthanasia or death:
  • Confirmed physical protrusion of the affected intervertebral disc at C6-7.
• Microscopic histopathologic evaluation:
  • Revealed lesions typical of compressive myelopathy (damage to the spinal cord caused by pressure).
  • Provided a pathological correlation to the imaging findings and clinical signs observed.

Importance and Novelty of the Case

• This report is the first documentation of intervertebral disc protrusion causing spinal cord compression in a horse confirmed through:
  • Multiple advanced imaging modalities—radiographic myelography, CT, MRI.
  • Direct macroscopic and microscopic postmortem examination.
• It expands the understanding of equine spinal disorders, as disc disease with protrusion is rare or underreported in horses compared to other species.
• The study emphasizes the value of comprehensive diagnostic approaches combining clinical examination, diverse imaging techniques, and histopathology for accurate diagnosis of neurological diseases in large animals.