Introduction
Ultrasound therapy is one of the therapeutic methods used by physical therapists in treating patients with injuries. It may require the physical therapists to apply the therapeutic ultrasound over the injured part as a part of the rehabilitation program. Ultrasound therapy involves a heating effect that sends a high-frequency sound wave inside the patient's body to treat the injured areas, such as tendons and muscles. Despite the use of ultrasound in treating patients with pain and musculoskeletal injuries and improved soft tissue healing, the effectiveness of the ultrasound remains questionable.
What is Ultrasound Therapy?
Ultrasound therapy is a deep heating agent capable of causing increased temperatures in tissues up to three to five centimeters deep. Ultrasound is a form of acoustic rather than electromagnetic energy producing longitudinal compressive waves which the human ear cannot hear. Ultrasound therapy can treat injuries like bursitis, tendonitis, arthritis, etc.
How Does Ultrasound Therapy Work?
The components of the ultrasound are the ultrasound probe, also called the ultrasound wand, which contains a crystal that vibrates, causing transmission of high-frequency sound waves into the patient's body in the injured area. For the crystal to vibrate, an electric charge is applied to them, creating a piezo-electric effect producing ultrasonic waves. The ultrasound waves do not transmit through the air, requiring a coupling medium such as gel, water, oil, or cream. The ultrasound probe is positioned at 90 degrees to the skin. Two common frequencies are used in rehabilitation:
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One MHz to penetrate the deeper tissues
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Three MHz to penetrate the superficial tissues.
The ultrasound can either use a pulsed wave, in which the intensity is periodically interrupted and the average power of the output over time is reduced, or a continuous wave, in which the intensity remains constant, and the energy is produced 100 % of the time. Desired effects of the ultrasound can be made in isolated deep tissues in our body without affecting the surrounding tissues.
What Are the Common Conditions Treated With Ultrasound?
Ultrasound is used in treating a wide range of health problems. Still, it is most commonly used in inflammatory conditions such as bursitis, tendonitis, conditions with chronic pain, muscle strain and tears, wound healing, osteoarthritis, frozen shoulder, conditions with tightness or contractures in improving the range of motion, non-acute joint swelling, and muscle spasm, subacute and chronic inflammation, and neuromas.
Ultrasound provides increased extensibility of collagen fibers, decreased joint stiffness, decreased muscle spasm, pain modulation, increased blood flow, and a mild inflammatory response.
What Are the Contraindications of Ultrasound Therapy?
There are a few contraindications of ultrasound therapy, such as:
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Insufficient arterial circulation.
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Active bleeding.
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Ultrasound over the eye causes cavitation in the fluid compartments.
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Pregnancy when used over the pelvic or lumbar areas.
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Around the eyes, heart, skull, or genitals.
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Contraindicated to donate over the spinal cord following a laminectomy because of the possible cavitation of the cerebrospinal fluid.
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Over the carotid sinus owing to possible disturbances of the heart's usual pacing or baroreceptors' stimulation.
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Over the areas of deep vein thrombosis.
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Over anesthetic areas.
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Over cancerous tumors.
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Sites of active infection or sepsis.
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Over fracture sites before healing is completed.
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Over pelvic and lumbar areas of a menstruating female patient.
Is Ultrasound Therapy Painful?
The patient will not feel any pain or burning sensation during the therapy. Ultrasound therapy is a pain-free and non-invasive treatment in physiotherapy. During the session, the patient will only feel the heat if the probe is in constant motion. The patient will feel pain or a burning sensation if the probe is kept in a single spot in the skin resulting in more vibrations. This is because the sound waves reflected from the injured area are too much, causing pain. Studies show that some physical therapists feel that the ultrasound can "hurt," making the patient believe that they need it to get better.
Is Ultrasound Therapy Effective?
Earlier studies show improved symptoms and healing using ultrasound therapy by physical therapists. But the quality of these studies could be better with no control groups. Many physical therapists still feel ultrasound therapy is an added positive outcome in any health condition.
But recent studies show that ultrasound therapy is more of a placebo effect and has minimal long-term benefits. The placebo effect is more than just positive thinking; it is a phenomenon in which the mind can trick you into thinking of having a positive therapeutic outcome over a fake treatment. i.e., you will feel better after the ultrasound therapy if the physical therapist tells you that it will feel better after receiving the treatment.
A research group once investigated the effects of ultrasound therapy on the lower limb in musculoskeletal conditions. Only one was considered to be of high quality in the 15 studies conducted by the research group. The results of these studies show that none of the placebo control groups has shown any significant benefit from ultrasound therapy. This indicated that people benefit from ultrasound therapy because of the placebo effect rather than physiological changes.
Why Should We Combine Ultrasound Therapy With Reinforcing Exercises?
Recent studies conducted by the Department of Physiotherapy at Tehran University of medical sciences aimed at investigating the effects of continuous ultrasound therapy combined with exercises in treating patients with chronic lower back pain. The studies showed significant improvement in function, range of motion, and pain management in patients who received ultrasound therapy and exercises.
Due to the lack of evidence showing substantial benefits from using ultrasound therapy alone, it should never be used as a primary treatment. Rather it can be used as a supplementation in treating people with pain and musculoskeletal disorders. Therapeutic ultrasound is practical only when combined with specific exercises which the physical therapist will recommend.
Conclusion
Broadly, ultrasound is believed to be a safe, effective, and non-invasive treatment modality used by physical therapists for years. The heating effect of ultrasound therapy is believed to improve the healing and pain in deep structures where the hot packs cannot be used. Studies might not support the use of ultrasound in physical therapy; however, It can be used in conjunction with other evidence-supported hands-on manual techniques and reinforcing exercises that the physical therapist will recommend.
