Although ultrasound is probably best known as a diagnostic tool, it’s also used to treat chronic pain and aid in a patient’s recovery from various soft tissue injuries. Treatment — referred to as therapeutic ultrasound — is noninvasive and requires no anesthesia. Research indicates it may result in pain relief, reduction of scar tissue and more efficient healing for many patients.
What Is Therapeutic Ultrasound?
Therapeutic ultrasound is a noninvasive procedure that uses low-power ultrasound waves to create vibrations and/or raise the temperature of body tissue in a targeted area, providing pain relief and loosening tight muscles. The procedure can also break up scar tissue and improve circulation of blood and lymph to promote healing of the affected area. It’s typically used to treat chronic pain and minor orthopedic injuries.
Therapeutic ultrasound is usually performed by a licensed physical therapist on an outpatient basis, but hospitals may also use this technique during inpatient stays to help patients recovering from orthopedic injuries or conditions.
How Does Therapeutic Ultrasound Work?
Ultrasound waves are produced when an electrical charge is applied to the small crystal that sits inside the ultrasound machine. These waves travel through the ultrasound head — or transducer — and are delivered to the injured soft tissue during treatment, increasing blood flow and oxygen delivery and producing therapeutic benefits.
Before treatment, the physical or occupational therapist or pain management physician chooses a section of skin near the injury site or where the pain originates, making sure there are no lesions or open wounds. The practitioner applies gel, sometimes mixed with a topical anti-inflammatory medication, to the targeted area and/or to the ultrasound’s transducer head. The therapist then glides the transducer over the targeted section of skin using circular motions.
During treatment, the practitioner may change the settings on the ultrasound machine to adjust the intensity or depth of penetration, depending on the injury’s current state of healing and how deep the damaged tissue is located. Patients remain awake throughout the treatment and usually feel nothing except the movement of the transducer. Some individuals may experience tingling, warmth in the area or a slight pulsing sensation, but the treatment is generally painless.
Types of Therapeutic Ultrasound
Two main types of ultrasounds are used for pain management: thermal and mechanical.
Thermal ultrasounds are generally used to treat pain caused by minor orthopedic injuries such as sprains and strains. During the procedure, an ultrasound machine delivers deep heat to a targeted area of the body. It can penetrate deep into the affected tissues, warming them to reduce pain, improve circulation and promote the healing process.
During a mechanical ultrasound, the machine delivers slight vibrations to soft tissue in the affected area, breaking down scar tissue and causing gas bubbles to form near the injury. Expansion and contraction of these bubbles may reduce injury-related swelling and inflammation, promoting soft-tissue healing.
Alternative Delivery Methods
Therapeutic ultrasound typically requires direct contact between the transducer and the patient’s skin. However, if the targeted area is bony or if the patient has an open wound, two alternative delivery methods are available: water immersion and the bladder technique.
Water Immersion Ultrasound
Certain areas of the body, such as the hands and feet, are too bony and uneven for traditional ultrasound delivery. During water immersion ultrasound, the body part that requires treatment is immersed in water and the ultrasound head is held about one centimeter above the skin rather than coming in direct contact with it. This eliminates resistance and lets the therapist effectively deliver ultrasound waves to the targeted area.
The Bladder Technique
Because patients with open wounds or sores are at risk of infection if the gel used in direct contact ultrasound gets in them, a practitioner may opt to deliver treatment using the bladder technique. For this technique, a small balloon or rubber glove is filled with water or gel and placed along the target area of the body. The transducer head is pressed against the balloon, which lets ultrasound waves pass through and into the body. This application method may also be used for treatment of irregular or bony parts of the body.