By Dr. Becker
Myofascial pain syndrome (MPS), also called chronic myofascial pain (CMP), is a fancy name for chronic muscle pain. “Myo” means muscles; “fascia” is the connective tissue surrounding muscles. MPS is caused by multiple trigger points (muscle knots) and fascial constrictions.
The function of fascia is to bind some structures together and allow other structures to glide easily over one another. Fascia is normally flexible and pliable. But when constriction occurs (from any number of causes), the tissue becomes inflamed. It tightens and shrinks, causing a great deal of pressure and tension on the structures it surrounds. Scar tissue forms in the muscle, and range of motion and flexibility are compromised.
Symptoms of MPS include tenderness, pain and hardening of the muscle on palpation, a sensation of weakness in the muscle, referred pain (pain in locations other than the trigger point), and decreased range of motion when pressure is applied very briefly to the trigger point. In dogs, the syndrome causes lameness.
How Myofascial Pain Syndrome Develops in Dogs
According to dvm360.com, although MPS has been a recognized condition for over 400 years and entered mainstream human medicine 80 years ago, the disorder is difficult to diagnose in dogs, and as a consequence, seldom treated. It’s almost never mentioned in veterinary schools, and no books have been written about it.
When a muscle or group of muscles isn’t working as it should, it can quickly cause a series of related problems including decreased joint function, and hypersensitivity of the spinal cord to stimuli, a condition known as central sensitization. Most veterinarians have had canine patients in their practice that don’t recover normally from successful orthopedic surgery. Many of these dogs probably have MPS.
Fortunately, most dogs with myofascial pain syndrome can regain normal mobility with proper treatment.
With MPS, there is always a rigid band of fibers within the sore muscle. Those fibers have multiple trigger points – extremely tender spots – that are typically caused when the fibers remain in a contracted state.
For example, if your dog has arthritis in a rear leg, he will attempt to keep weight off the painful joint by assuming a position that requires a slight contraction of specific muscles. This repositioning protects the sore joint, but it also eventually causes trigger points to develop. Trigger points are typically formed in groups bunched within a muscle, and it’s not unusual to have a dozen very tender spots in a single muscle.
Diagnosing MPS in a Dog
When a trigger point on a dog is touched, even gently, the dog will often jump in response and look in the direction of the trigger point. If the pressure is increased, the dog may cry out, show aggression, or try to escape.
Accurate diagnosis of trigger points takes some practice. The area must be gently palpated with either a flat or gripped hand, depending on the type of muscle involved. The palpation should be performed perpendicular to muscle fibers in order to reveal trigger points.
The taut bands within the muscle will feel slightly thickened. To identify the area as a trigger point, the vet should use his or her fingers to apply additional pressure to measure the dog’s response.
Treating Myofascial Pain Syndrome
According to Dr. Michael Petty of the Canine Rehabilitation Institute, writing for dvm360.com, the most effective and economical treatment for trigger points in dogs is a procedure called dry needling.
An acupuncture needle is used to locate the trigger point. When contact is made with the trigger point, an involuntary twitch occurs that involves a spinal reflex loop, which is a pathway in the spinal cord that allows sensory information to be processed without having to travel all the way to the brain for a response. The short distance the signal has to travel makes the body’s reaction much quicker, protecting it from injury. A reflex loop or arc is in play when your hand touches a hot surface and you unconsciously move it to avoid a burn.
In a dog with trigger points, the contraction is released as a result of the spinal reflex loop, and the relief the dog gets is almost immediate. Some dogs require sedation during the procedure depending on the level of pain and also the animal’s temperament.
Length of treatment depends on the patient and the muscle(s) involved. Dry needling sessions typically last around 20 minutes and are done weekly until the dog shows improvement and feels comfortable.
Only the trigger points causing a problem are treated. Unfortunately, these tender spots are permanent. Once they are successfully treated, they can stay dormant for short or long periods of time, but they always have the potential to become active again.
How to Find Out More About Myofascial Pain Syndrome and Trigger Point Therapy
Despite lack of formal training programs for treating myofascial pain in animals, all veterinarians should be familiar with the syndrome and its effect on a dog’s ability to recover from surgery, injury or illness. Fortunately, the dry needling technique for treating MPS can be highly effective and return normal mobility and quality of life.
The International Veterinary Academy of Pain Management will give a one-day seminar on myofascial pain syndrome at the 2013 American Animal Hospital Association (AAHA) conference in Phoenix.
You can also learn more about trigger point therapy through Colorado State University's Center for Comparative and Integrative Pain Medicine or Myopain Seminars.
Additional Help for Dogs with Arthritis or Degenerative Joint Disease
If your dog has arthritis or degenerative joint disease that is causing myofascial pain syndrome, you’ll want to make sure she stays at a healthy weight (or is dieted down to a good weight), and has regular opportunities to be physically active.
Chiropractic adjustments, massage, stretching, aquatic therapy and acupuncture are therapies that can make a world of difference in the mobility of pets with arthritis and joint problems. Talk with your holistic vet about supplements you can add to your dog’s diet to help maintain healthy tendons, ligaments, joints and cartilage. Some of these might include:
- A glucosamine sulfate with MSM and eggshell membrane supplement
- Omega-3 fats (krill oil)
- Supergreen foods like spirulina and astaxanthin
- Adequan injections, which can stimulate joint fluid very rapidly in pets with arthritis