Spinal cord compression in cats and dogs

By Dr Oliver Wilkinson BVSC MRCVS, Dragon Vet Centre, Cheltenham

The average dog and cat has 7 bones in their neck, 20 in their back and 3 in the sacrum (bones that pass through and connectvto the pelvis). They also have anywhere from 5 to 23 bones in their tails. That’s a total of somewhere between 35 and 58 spinal vertebrae/bones. The most important are the first 30 from the back of the skull to the top of the tail.

These bones provide a bony cage through which the delicate nervous tissue of the spinal cord travels. With the exception of the 3 sacral bones, which are fused, the rest of these vertebral bones articulate, moving against each other to allow curvature and movement of the spine. They are cushioned between each other by shock-absorbing, intervertebral discs that absorb compression and stress to the spine.

When everything is working well the spinal column is an incredibly clever, stabile and effective structure that allows us to twist our necks, look up to the sky and down to the floor, bend down to pick things up and swivel around. Unfortunately sometimes things do go wrong.

One of the more common problems is when a disc ‘prolapses’. This is usually when the outer fibrous part of a disc tears or fissures and the soft gel like interior is propelled into the space where the nerves travel, this is known as Hansen type-I disc disease. Alternatively the outer part of the disc (the annulus) itself can bulge into the spinal cord and impinge on the nerves, this is known as Hansen type-II disc disease.

Compression on the spinal cord can cause intense pain, temporary nerve damage or in extreme cases permanent paralysis. Treatment might be conservative with powerful antiinflammatories and pain relief to treat the symptoms. This is more likely when there isn’t significant nerve function impairment. If spinal cord damage is significant then surgery to relieve pressure from a ruptured or bulging disc may be required. Diagnosis is usually achieved with radiography or more accurately with MRI or CT imaging of the individual discs.

Surgery on the spinal cord can involve either a ‘fenestration’, which involves cutting into the disc to remove the internal spongy gel and prevent further spinal cord damage or it can involve ‘decompressive’ surgery to cut away the bone protecting the spinal cord allowing access to remove prolapsed disc material from around the nerves themselves.

Whether surgery is indicated or conservative treatment is chosen, back disease can be recurrent and recovery from an episode of spinal cord compression is likely to be prolonged and require a holistic approach. Medication +/- surgery and rest in the short term may be advised but long term weight management, physiotherapy and rehabilitation are likely to be key to a successful recovery.

ULTRASOUND TREATMENT

K-9 Ultrasound treatment can begin a week after surgery to treat the surrounding areas and compensations, but it should not be applied directly on the incision area until the skin is completely closed and the stitches have been removed. Once the incision site has completely healed, ultrasound can be applied directly on scar tissue.

Ultrasound therapy can stimulate both angiogenesis (the formation of new blood vessels) and bone morphogenetic factors; it appears to induce the differentiation of the osteoblast and promote osteogenesis. Furthermore K-9 Ultrasound therapeutic treatments help to reduce pain following surgery by effecting nerve fiber conduction.

The healing process following surgery very often leaves pronounced scar tissue and adhesions, which are made of generic connective tissue, rather than specialised connective tissue. This generic connective tissue is qualitatively inferior and adheres to skin, tendons, ligaments and bone.

Hypertrophic or keloid scarring and adhesions can entrap nerves causing pain and consequently limiting normal joint range of motion.

Ultrasound energy is absorbed into the tissues with high collagen content, like scar tissue and adhesions. Scar tissue and adhesions are denser than surrounding tissues and thus absorb more ultrasound energy. With the need for selective treatments depending on the tissue being treated, K-9 Ultrasound can offer a variety of probes to meet every need.

Mechanical non-thermal effects generated by K-9 Ultrasound white hand probes help softening scar tissue and adhesions, while diathermy / deep heat generated by K-9 Ultrasound red hand probes increase local vasodilation, blood flow and soft tissue extensibility.

Treatment recommendation for scar tissue softening is between 7 and 10 minutes every other day for a maximum of 2 weeks.

When treating Ligament injuries, desmitis and ligament inflammations, treatment time should be 8–10 minutes 2–3 times a week for a maximum of 4 weeks.

 

Animal Therapy Magazine