Therapeutic ultrasound is used primarily for two different effects: the deep heating treatment and non-thermal uses.
Deep Heating Effects: Ultrasound is often used to provide deep heating to soft tissue structures in the body. Deep heating tendons, muscles or ligaments increases circulation to those tissues, which is thought to help the healing process. Increasing tissue temperature with ultrasound is also used to help decrease pain.
Deep heating can be used to increase the “stretchiness” of muscles and tendons that may be tight. If you have shoulder pain and have been diagnosed with a frozen shoulder, your physical therapist may use ultrasound to help improve the extensibility of the tissues around your shoulder prior to performing range of motion exercises. This may help improve the ability of your shoulder to stretch.
Non-Thermal Effects (Cavitation): Ultrasound introduces energy into the body. This energy causes microscopic gas bubbles around your tissues to expand and contract rapidly, a process called cavitation. It is theorized that the expansion and contraction of these bubbles help speed cellular processes and improves healing of injured tissue.
Inside your doctor’s ultrasound unit is a small crystal. When an electrical charge is applied to this crystal, it vibrates rapidly, creating piezoelectric waves. These waves are emitted from the ultrasound sound head as ultrasound waves. The ultrasound wave then enters into your injured tissues during application of the modality. This increases blood flow and caviation, leading to the theorized benefits of the treatment.
Usually, orthopedic injuries are treated with ultrasound. These may include:
Generally speaking, any soft-tissue injury in the body may be a candidate for ultrasound therapy. Your doctor may use ultrasound for low back pain, neck pain, rotator cuff tears, knee meniscus tears, or ankle sprains.
While you are receiving an ultrasound treatment, you will most likely not feel anything happening, except perhaps a slight warming sensation or tingling around the area being treated. If the ultrasound sound head is left in place on your skin and not moved in a circular direction, you may experience pain. If this occurs, tell your physical therapist right away.