Neuroanatomic and pathophysiologic aspects of intervertebral disc disease in the dog

A sound understanding of anatomy and the pathophysiology of disease is important in all branches of medicine, but nowhere is it more critical to success than in the medical and surgical management of intervertebral disc disease. Due to the remote location and unforgiving nature of the spinal cord, the veterinary surgeon must possess an intimate working knowledge of the surgical anatomy of the vertebrae, ligaments and joints of the spine, intervertebral discs, spinal cord, and spinal nerves. In addition, proper localization of spinal cord lesions during the neurological evaluation requires awareness of the functional neuroanatomy of the upper and lower motor motor neurons, the sensory systems and tracts, and the reflex arcs. Knowledge of the pathophysiology the intervertebral disc degeneration and the response of the spinal cord to disc extrusions are also important in the overall understanding of the disease and enhances proper decision making for its management. This chapter reviews the portions of the gross and functional neuroanatomy and the pathophysiology of the intervertebral disc and the spinal cord that are pertinent to the dog with intervertebral disc disease. Emphasis is placed on concepts that are critical for the veterinary surgeon who is involved in the surgical management of the disc patient.