- Myofascial pain
- Carpal tunnel syndrome
- Pain caused by scar tissue
- Phantom limb pain
- Sprains and strains
If your doctor has ordered you to see a physical or occupational therapist for ultrasound therapy, here is what you can expect.
Types of Ultrasound Therapy
There are two main types of ultrasound therapy: thermal and mechanical. Both use sound waves generated through a transducer head (which looks a bit like a microphone) to penetrate soft tissues. The difference between the two types of ultrasound therapy is the rate at which the sound waves penetrate the tissues.
- Thermal ultrasound therapy. Thermal ultrasound therapy uses a more continuous transmission of sound waves. The sound waves cause microscopic vibrations in the deep tissue molecules, increasing heat and friction. The warming effect encourages healing in the soft tissues by increasing the metabolism at the level of the tissue cells.
- Mechanical ultrasound therapy. Mechanical ultrasound therapy uses pulses of sound waves to penetrate tissues. While this still has a minor warming effect on the tissues, it also causes expansion and contraction in the tiny gas bubbles of the soft tissues. This helps to decrease the inflammatory response, reducing tissue swelling and thus decreasing pain.
The type of ultrasound therapy you receive depends on your condition. If you have myofascial pain, or had a muscle strain or sprain that has not healed, your therapist will likely use thermal ultrasound therapy. If your pain is caused by scar tissue or swelling, such as with carpal tunnel syndrome, you may benefit more from mechanical ultrasound therapy.
How Ultrasound Therapy Is Performed
Your therapist will select a small surface area to work on for anywhere from five to 10 minutes. Gel is applied either to the transducer head or to your skin, which helps the sound waves evenly penetrate the skin. During your ultrasound therapy treatment, your therapist will continually move the transducer head over and around the selected area.
Will I Feel Anything During Ultrasound Therapy?
Some people feel a mild pulsing during ultrasound therapy, while others may feel slight warmth in the skin. Don’t be surprised, however, if you feel nothing at all, apart from the cold gel on your skin. If the area being treated is especially sensitive to touch, you could possibly feel discomfort as the transducer head passes over. Ultrasound therapy, however, should not be painful.
Is Ultrasound Therapy Safe?
Ultrasound therapy is deemed safe by the FDA provided it is performed by a licensed person, and provided the therapist keeps the transducer head moving at all times. If the transducer head remains in one place for too long, there is potential to burn the tissues underneath, which you may or may not feel.
Ultrasound therapy should not be used on these body parts:
- Over the abdomen, pelvic regions or lower back in women who are menstruating or pregnant
- Over lesions, broken skin or healing fractures
- Around the eyes, breasts or sexual organs
- Over any areas with plastic implants
- Over or near areas with malignant tumors
- Over areas with impaired sensations or blood flow
Additionally, it not be used on people who have pacemakers.
Does Ultrasound Therapy Really Work?
The literature is mixed on the benefits of ultrasound therapy. Some studies show that it can effectively control certain types of chronic pain, while others say there is little difference between ultrasound therapy and other traditional therapy treatments (such as heat, stretching and electrical stimulation) for pain control.
My experience as an occupational therapist is that ultrasound therapy either works very well, or not at all. Much like pain medication, finding the treatment modality that decreases your pain is often a trial and error process. If you have not had any improvement in your pain after several ultrasound treatments, ask your therapist or doctor about trying something else.
Belanger, Alain-Yvan. Evidence-Based Guide to Therapeutic Physical Agents. Lippincott Williams & Williams. 2003.
Deutscher D, Horn SD, Dickstein R et al. Associations Between Treatment Processes, Patient Characteristics, and Outcomes in Outpatient Physical Therapy Practice. Archives of Physical Medicine and Rehabilitation. 2009 Aug;90(8):1349-63
Durmus D, Durmaz Y, Canturk F. Effects of Therapeutic Ultrasound and Electrical Stimulation Program on Pain, Trunk Muscle Strength, Disability, Walking Performance, Quality of Life, and Depression in Patients with Low Back Pain: a Randomized-controlled Trial. Rheumatology International. 2009 Jul 31
FDA U.S. Food and Drug Administration. Ultrasonic Therapy Product or Ultrasonic Diathermy. Accessed 8/11/09. http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/SurgicalandTherapeutic/ucm115937.htm