What Is Therapeutic Ultrasound?

Therapeutic ultrasound for chronic pain

When most people think of an ultrasound, they envision a doppler type of scan used to monitor pregnancies and to diagnose medical issues; however, an ultrasound can also be used for medical treatment. Therapeutic ultrasound, or ultrasound therapy, is a non-invasive, medication-free procedure that has been used to treat various chronic pain conditions since the 1940s. It is typically performed by a trained physical therapist in an outpatient setting; it is also used in hospitals for certain injuries and conditions during the recovery process. Two types of therapeutic ultrasound are available: thermal and mechanical.

Thermal therapeutic ultrasound

Thermal therapeutic ultrasound applies deep heat to a specific area using an ultrasound machine. It penetrates deep into the tissues, warming them, to encourage the healing process. Thermal therapeutic ultrasound is primarily used for pain caused by sprains and strains.

Mechanical therapeutic ultrasound

Mechanical therapeutic ultrasound uses an ultrasound machine to cause slight vibrations in the soft tissue which creates gas bubbles near the injury that expand and contract, a process called cavitation. This promotes healing by reducing swelling and inflammation due to injury. Mechanical therapeutic ultrasound can also be used to break down the buildup of scar tissue, also known as fibrosis. Like thermal therapeutic ultrasound, mechanical therapeutic ultrasound promotes soft tissue healing.

The process of therapeutic ultrasound

A therapist selects a small surface area of the skin closest to the site of injury or pain. A gel is then applied to the skin or the transducer head of the ultrasound machine. The therapist continually glides the transducer over the affected area in circular-like movements. Individuals have reported experiencing a slight pulsing feeling or a slight warmth in the area where the therapy applied. In most cases, nothing except the movement from the transducer is felt, which does not cause pain.

Risks of therapeutic ultrasound

Therapeutic ultrasound is FDA approved for use by licensed professionals. If any discomfort is felt during the treatment, the practitioner should be notified immediately because discomfort is not a normal response. There is a potential risk of a "microplosion" which could disrupt cellular activity and cause damage. This is caused by rapid pressure changes during the cavitation. ​This type of therapy should never be used over an open wound, on pregnant women or on people with an implanted device, such as a pacemaker.