Back problems are a common cause of pain and poor performance in horses of all types, with signs that range from sensitivity to grooming through to violent behaviour when saddled.

Identifying that there is a problem is relatively easy, but localising the site and cause of the pain can be time consuming, complex and expensive.

Accurate diagnosis is, however, crucial for selecting the most effective therapy and developing an appropriate rehabilitation programme. This is achieved by combining careful clinical assessment with one or more diagnostic procedures, which are outlined in this article.

Horses with back pain are invariably presented for veterinary examination for one of two reasons. Either the rider or trainer may have become aware of signs that suggest a back problem, or there has been a baffling deterioration in the horse’s performance. Examples of the latter include poor dressage marks and an uncharacteristic four faults when jumping, as well as refusals and eliminations.

Signs of back pain vary according to the site, nature and severity of the underlying cause, and can be influenced by the horse’s temperament and the way in which he or she is ridden.

The horse may be stiff on one or both reins, reluctant to move forward or work ‘on the bit’, short behind, or resists movements that require the spine to flex from side to side or in a vertical plane. The shape of the jump may change or the horse may start to refuse, knowing that the compression of the spine on landing is going to be painful.

Observing the horse moving in hand, on a lunge and under saddle are the first steps in the veterinary examination. As the horse moves attention is directed to any signs of pain or resistance, as well as looking at how the neck and back are moving and the extent to which the hindlimbs are active and engaged. The horse’s attitude and demeanour are important too.

It is important to look for any evidence of lameness, since low-grade but long-standing problems like foot soreness, bone spavin and suspensory ligament strains can cause back pain. Flexion tests should also be performed and nerve blocks may be required to clarify if there is any underlying lameness, especially when both of the front or hind limbs are affected.

Comparing the movement on the lunge with that when ridden can indicate whether the saddle fitting or rider weight is contributing to the problem. Buck, rearing, hollowing of the back, together with a raised head carriage and shortened stride behind, when ridden are all suggestive of an issue with the saddle or rider.

Lungeing with side reins, a chambon or de gogue may also highlight a problem that is not apparent when the horse is lunged loose, since these training aids require that the head is carried long and low, stretching the ligament that runs from the poll to the sacrum.

The mouth should also be thoroughly inspected as painful dental conditions can alter the horse’s movement and contribute to a sore back.

The next step in the veterinary examination is to palpate the back. I initially run my hands down each side of the neck and back feeling for any stiffness. The muscles should feel soft and relaxed, without out any tension, and appear symmetrical from left to right.

I then apply pressure to each side of the neck and back with my finger tips – others use the barrel of a pen – and look for any discomfort. Pressure should also be applied along the midline of the back, over the supraspinous ligament, as well as simultaneously on both sides of the back muscles.

Signs of pain include the horse becoming agitated, flattening his ears back, turning his head around, and attempting to move away from the point contact or bucking. It is important to realise that it is a normal reflex for the back to bend away from any such contact, but this does not elicit a conscious response from the horse. Conversely a rigid back, which fails to flex in response to palpation, is indicative of discomfort.

An internal examination will also allow for palpation of the structures of the pelvis and the deep lumbar muscles. Painful reactions can indicate damage to the soft tissues surrounding the sacroiliac joints, as well as tears in the adjacent muscles.

Through detailed inspection and careful palpation it is usually possible to identify the area of pain for further investigation. Thermography, using a heat-sensitive camera to identify areas of increased blood flow or inflammation, can also help in this regard.

A bone scan (scintigraphy) is a useful, albeit expensive, technique for localising the affected area and may provide clues to the nature of the damage. It also offers the advantage of concurrently evaluating the limbs for any problems that may be contributing to the back pain.

At this stage it can be tempting to move straight onto treating the back, either medically or using physiotherapy and other manipulative therapies. While this may well relieve the muscle spasm and pain, it does not necessarily address the underlying condition and the benefits can be short-lived. Rapid recurrence of discomfort, or the need for frequent treatment, is reason to investigate the problem more fully.

The most commonly used diagnostic technique is radiography. This allows for detailed examination of bony structures, especially in the neck where the images can be inspected for signs of arthritis affecting the vertebrae. It is more difficult to fully evaluate the back with X-rays because of the thickness of the muscle tissues in these areas.

This said damage to the dorsal spinous processes and the condition known as ‘kissing spines’ are easily visible on X-rays of the thoracic and lumbar regions of the back. There may be narrowing of the spaces between adjacent spinous processes, with new bone being formed and other areas where bone is lost.

The soft tissues of the back – namely the muscles and ligaments – are best visualised using ultrasonography. This is particularly useful in diagnosing damage to the supraspinous ligament, the muscles along the back, and the ligaments associated with the sacroiliac joints. Ultrasonography can also be used to examine the joints between vertebrae in the thoracic and lumbar regions of the spine.

One of the issues with techniques used to image the back – including scintigraphy, radiography and ultrasonography - is that they don’t necessarily indicate whether the damage identified is the cause of the pain. For instance it is not uncommon to find impinging dorsal spinous processes in an area of the back some distance from where the discomfort is centred. If these are not the source of the problem, then their treatment will not alleviate the back pain.

For this reason it is sometimes necessary to infiltrate the damaged area with local anaesthetic and then re-examine the horse. If the damage is clinically significant, the loss of sensation with the injection will improve the horse’s attitude, behaviour and gait.

The goal of these procedures is to identify the precise location and nature of the injury, so that an appropriate treatment can be selected and targeted at the area of damage. This may well involve veterinary medication as well as manipulative therapies and acupuncture, which are discussed in the next issue.