Canine Intervertebral Disc Disease Study Guide

Overview and Clinical Importance

Intervertebral disc disease (IVDD) is the most common cause of spinal cord injury in dogs and represents a significant category of neurological disease on the NAVLE examination. This condition occurs when the intervertebral disc degenerates and herniates, causing compression and/or contusion of the spinal cord. Understanding the pathophysiology, clinical presentation, diagnostic approach, and treatment options is essential for successful case management.

The intervertebral disc consists of two main components: the nucleus pulposus (a gelatinous center rich in proteoglycans and water) and the annulus fibrosus (a concentric ring of fibrous lamellae composed primarily of collagen). Disc degeneration leads to loss of shock-absorbing capacity and can result in herniation and spinal cord compression.

Pathophysiology and Classification

Hansen Classification System

The Hansen classification system, developed in the 1950s, remains the foundation for understanding IVDD pathology. The system is based on the type of disc degeneration and the nature of disc herniation.