Therapeutic Ultrasound

By Malcolm Weir, DVM, MSc, MPH; Robin Downing, DVM, CVPP, CCRP, DAAPM

What is therapeutic ultrasound, and how does it work?

Therapeutic ultrasound is a treatment method that applies thermal, mechanical, and chemical effects to tissues to improve healing. Physical therapists have used therapeutic ultrasound on human patients since the 1940s, and veterinarians have used it on animals since the 1970s.

The sound waves of therapeutic ultrasound are produced by applying an electric current to a crystal, causing the crystal to vibrate at a specific frequency. The vibrations of the crystal within the head of the ultrasound probe create pulsed or continuous pressure waves (energy) that pass through the skin and vibrate the tissues. The ultrasound probe is applied directly against the pet’s skin using a water-soluble ultrasound gel.

Most people are more familiar with diagnostic ultrasound, which is used to look inside the body in non-invasive ways. We use diagnostic ultrasound to evaluate the heart as it beats and see the size, shape, and structure of organs in the abdomen. This type of ultrasound shows what babies look like in the uterus.

What types of conditions benefit from therapeutic ultrasound?

Therapeutic ultrasound can be used to increase the stretch in fibrous tissues (such as tendons), which can help increase range of motion around a joint. Therapeutic ultrasound can also be used to soften and break down scar tissue that interferes with movement. By deep heating the tissues, therapeutic ultrasound increases blood flow to the area. This in turn can increase local blood flow and reduce inflammation and swelling. Therapeutic ultrasound can also decrease pain and muscle spasms, as well as speed up wound healing.

What happens during a therapeutic ultrasound treatment session? Will my pet be sedated?

Pets are not sedated during a therapeutic ultrasound session. They must be able to indicate (by squirming or moving away) if the treatment makes them uncomfortable. The goal is always to have physical medicine treatments feel good to the patient.

The pet’s hair is shaved over the area to be treated, and the clinician applies ultrasound gel to the pet’s skin. The therapeutic ultrasound head is then moved steadily over the treatment area in overlapping circles.

How long does a treatment take, and how often will my pet need therapeutic ultrasound?

Most treatment sessions last 10 to 20 minutes, and most patients are treated for two to three sessions per week until the condition is resolved. Therapeutic ultrasound is generally used along with other physical medicine and pain management strategies.

Are there any reasons not to use therapeutic ultrasound on a pet?

Therapeutic ultrasound should not be used over orthopedic implants, such as total hip replacements, or bone plates, such as those used for fracture repair. Therapeutic ultrasound over implants can cause “superheating” of the surrounding areas and result in discomfort and tissue damage. Therapeutic ultrasound also should not be applied over tumors, in animals with pacemakers, in infected areas, over pregnancies, over growth plates of young animals’ bones, over the open spinal cord following spine surgery, over the eyes or skull, or over the testicles of a non-neutered male pet.

Because therapeutic ultrasound has the potential to cause tissue damage, only professionals who have been appropriately trained in its use should treat your pet.

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