Dr John Kohnke

‘Health Care and problems of Horses" (9th edition-Virbac-Vetsearch)

Competitive sports such as racing, showjumping and eventing increase the risk of spinal and back injuries in horses. About 1% of all lameness problems involve the back with the highest incidence recorded in harness racing, eventing, hunting, dressage, draft and endurance horses.

The horse does not have the soft 'shock absorbing' discs between the vertebrae found in man and many other animals. The discs have a solid core, making the spine a relatively rigid structure. The only point where major rotational (side to side) movement can occur is the lumbosacral joint (the so called 'coupling' joint), where the last lumbar spine vertebra joins onto the pelvic vertebrae on the midline just in front of the pin bones.

In harness racing horses, the pacing gait results in an unnatural 'rolling' action as the horse bears weight on the fore and hind legs on the same side in an alternate sequence. This increases the rotational movement of the 'coupling' joint, which can result in the development of arthritis within the joint.

The typical 'hunters bump' that develops behind the pin bones on each side of the midline is caused by strain of the sacroiliac ligaments, and upward movement of the sacroiliac joint. Many authorities believe that most chronic low-grade back problems result from a mild form of sacroiliac joint instability in riding and pleasure horses.

Other muscles and ligaments in the pelvic area, such as sacro-iliac, sacro-sciatic, and iliolumbar ligaments help stabilise and strengthen the lower back and pelvic structures. Strain caused by hard work, falls, over flexion, the pacing action and awkward landing from a jump, etc. can cause ligament and muscle tearing and subsequent lameness and loss of performance.

Symptoms

Clinical signs of back pain and injury include:

- reduced ability to jump

- poor performance

- 'lugging' to one side

- head shaking

- tail swishing

- bucking and

- resentment of extra weight when the rider first mounts.

One consistent feature is alteration in the horse's behaviour or temperament, even without a noticeable change in performance or other signs of discomfort. These signs include a bitchy or sour nature when worked or ridden, and often resentment when being groomed over the back area.

Diagnosis

Diagnosis is a job for your vet. For example, 'coupling' joint arthritis can be indicated by a tendency to 'sit down' or 'sink in the back' when the coupling area (level with the pin bones) is pressed downwards with the thumbs. In some cases, X-rays may help confirm spinal injury or arthritis.

Lumbo-pelvic ligament pain can be located by careful examination in a resting horse. Other underlying common problems, such as high inside heels on the hind hooves, hock and stifle pain or arthritis should also be assessed.

Treatment and management

A wide variety of treatment and management options can provide relief from back pain. However, it is essential that any underlying hock, stifle or other limb injuries that predispose a horse to back problems are fully investigated and treated, otherwise the back problems will persist.

Conventional veterinary treatment involves the careful use of anti-inflammatory medications, often combined with rest periods of up to 6-9 months in more serious cases. Because of the difficulty of diagnosing and treating back pain, chiropractic 'adjustment' and 'manipulation', often by untrained personnel, has become a popular alternative. Although it is virtually impossible to realign and adjust the pelvic skeleton in a non-anaesthetised or fully aware horse, particularly one that resists and resents manipulation, simple muscle massage may relax spasms and provide temporary relief, especially when combined with 10-14 days of light work or rest.

Use of other physiotherapy aids, such as laser therapy, magnetic field therapy (with machine pads or applying a magnetic blanket overnight) and acupuncture may also provide relief in chronic cases.

For relief of minor discomfort, massage twice daily for 5 minutes over each side of the pin bones and rump with products such as Rapigel or R-Iodine, whilst the horse is standing relaxed when feeding for 7-10 days.

Where arthritis of the 'coupling' joint, or sprain of the sacro-iliac ligaments is suspected, application of Dermcusal combined with light work for 7-10 days can provide long term relief in harness racing and pleasure horses. In harmess racing horses, loosen the head check on hobbling days, or gallop instead of hobbling and pacing for a fast workout.