Equine Spinal Pathology

Original Editor - Ansi van der Walt Top Contributors - Jess Bell, Kim Jackson and Tarina van der Stockt

Introduction

Back-pain is a common issue in horses, potentially causing chronic pain, muscle wastage, reduced performance, and decreased ability to work.

Obtaining a definitive diagnosis is, however, difficult because of difficulties accessing the area, variability in pain manifestations and vague clinical signs. There is also a lack of knowledge about the equine thoracolumbar spine (particularly its functional aspects) and the pathogenesis of back problems in horses. Moreover, some horses can continue to perform well despite back pathology, but others will perform poorly in the absence of specific spinal dysfunction.

Back problems in horses are often related to chronic or long-standing injuries. There may also be more than one spinal lesion affecting the horse’s performance and causing symptoms. It is, therefore, important to confirm if there are any secondary lesions in order to provide a realistic prognosis and develop an optimal management plan.

Differential Diagnosis

Equine back disorders can be classified as primary or secondary.

Primary Back Problems

Primary disorders relate to lesions in the spinal structures, including muscle, ligament, osseous / vertebral, and nerve injuries.  The following table, adapted from Hinchcliffe and colleagues, lists common primary back problems.

Soft Tissue Injury	Osseous Injury	Neurological Injury	Other
Longissimus muscle strain	Conformational / developmental abnormality	Equine protozoal myeloencephalitis	Tack and saddle fit
Supraspinous ligament sprain or desmitis	Overriding dorsal spinous processes (OSP)	Equine degenerative myeloencephalopathy	Idiopathic
Dorsal sacroiliac ligament sprain or desmitis	Osteoarthritis	Equine herpesvirus myeloencephalitis
Exertional rhabdomyolysis	Vertebral fracture	Equine notor neuron disease
Non-specific soft tissue injury	Spondylosis
	Discospondylitis
	Spinal neoplasia