Therapeutic ultrasound is a treatment modality commonly used in physical therapy. It is used to provide deep heating to soft tissues in the body to treat chronic pain and promote tissue healing. These tissues include muscles, tendons, joints, and ligaments. Ultrasound is too often confused with diagnostic ultrasound, which is an ultrasound that is used to see the inside of the body, such as checking on a fetus during pregnancy.


Historically, ultrasound in physical therapy proved to be highly effective in improving overall blood circulation and faster healing than traditional methods. While ultrasound therapy is not effective for all kinds of chronic pain conditions, it is certainly very helpful to heal the following:

  • Osteoarthritis

  • Limb Sprains

  • Myofascial pain

  • Carpal tunnel syndrome

  • Pain caused by scars

  • Phantom limb pain

Any soft-tissue injury in the body can be referred to as ultrasound therapy. In fact, ultrasound can help with lower back pain, neck pain, rotator cuff tears, knee meniscus tears, or ankle sprains, muscle strains and tears, frozen shoulder, ligament injuries, joint contracture or tightness etc.


By increasing blood flow, ultrasound therapy securely reduces local swelling and chronic inflammation and according to some medical studies, also promotes bone fracture healing. However, ultrasound is a passive treatment. Active exercise and self- care rehab is more effective than ultrasound merely, yet it remains to be popular among fields like sports and medicine.


How is Ultrasound Therapy Performed?



Inside an ultrasound unit is a small crystal. When an electrical charge is applied to that crystal, it vibrates rapidly, creating piezoelectric waves. A Gel is applied to the injured area of one’s skin or to the transducer head before massaging with the ultrasound for about 5-10 minutes, which helps the sound waves to evenly penetrate the skin. During the ultrasound therapy treatment, the therapist will continually move the transducer head over and around the selected area.


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.

The difference between thermal and mechanical ultrasound therapy is the rate at which the sound waves penetrate the tissues.


  • Thermal Ultrasound Therapy: Thermal ultrasound therapy uses a 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. This happens as a result of the ‘deep heating effect’ in the body.

  • Mechanical Ultrasound Therapy: Mechanical ultrasound therapy uses pulses of sound waves to penetrate tissues. Besides having a minor warming effect on the tissues, this technique 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. This process is called ‘Cavitation’.


What Does Ultrasound Feel Like?


While receiving an ultrasound treatment, one will most likely not feel anything, except perhaps a slight warming sensation or tingling around the area being treated. This is because the transducer sends high- frequency sound waves through the body, and it is only possible to feel them if they hit a dense object- muscle under the skin, in this case.


However, if the ultrasound’s head is left in place on your skin and not moved in a circular direction, you may experience pain. If this occurs, one must notify their therapist immediately. Otherwise, ultrasound is a safe and harmless treatment in physical therapy. Sometimes, in order to attract attention, therapists may condition people into thinking that ultrasound therapy can hurt, but any injury from ultrasound is completely the responsibility of the therapist and has nothing to do with the process itself.


Do Not Resort to Ultrasound Therapy For


  • Cancer: Ultrasound increases cellular activity in the body. Hence, it should not be used on cancerous areas as it can possibly increase the chances of metastasis in the cancer body.

  • In Children: Ultrasound can damage bones that are not fully grown and cause problems in the skeletal structure that can seriously affect bone growth.

  • Near The Eyes: The therapy can cause damage to the retina or the lens of the eyes when in close contact with ultrasound.

  • In Areas With Decreased Sensitivity: If an injury prevents you from feeling normal hot and cold temperatures, ultrasound should not be used since you would not be able to report any discomfort or burning sensations to your physical therapist.

  • Areas Around The Heart: It has been observed in some cases that ultrasound may alter the electrical signals around the heart. Especially if one has a pacemaker, ultrasound may interfere with its normal function.

Therapy from Ultrasound must also be strictly avoided in the cases of open wounds, parts of the body with metal implants (if present), like in a total knee replacement or lumbar fusion, during pregnancy, around sexual organs, near or over any implanted electrical stimulation device etc.


The Placebo Effect


Ultrasound is a safe treatment that has been used over for years now in physical therapy. But contrary to popular belief, studies about the usage of ultrasound therapy to speed up healing resulted in the knowledge that, except in the case of shoulder pain, ultrasound did not help in speedy recovery.


Yet, many physical therapists continue to use ultrasound as an integral part of treatment and many people feel that it adds positive outcomes in the treatment of their conditions, which is really just a ‘Placebo effect.’


The placebo effect is a phenomenon where you perceive an improvement in your condition simply because something is being done to you. If your physical therapist tells you that ultrasound treatments can make you better, you psychologically start to feel better after receiving the treatments. This might actually be advantageous when the placebo effect actually helps you to recover mentally and physically, but one should be aware that it is possible for a therapist to simply persuade you unethically, into an unnecessary ultrasound therapy.


Ultrasound for Chronic Pain


Ultimately, there is some legitimate evidence of benefitting from an ultrasound if one is suffering from chronic pain. The waves stimulated by the ultrasound help in improving tissue extensibility and blood circulation, leading to increased mobility, resulting in decreased pain. Ultrasound may not work for everyone, but it is worth a try if you have been suffering for a long time, and the therapy will most likely help you if there is a right treatment.


Conclusion


As of now, there seems to be little evidence scientifically to support ultrasound therapy and to back the effectiveness of its techniques. You can always rightfully question the credibility or the necessity of an ultrasound therapy if suggested.


If you do opt to receive an ultrasound, you must be aware of what ultrasound is and what it promises to do and what it cannot. Micro massaging is one of the most effective ways of healing and regenerating tissue cells, which the ultrasound is capable of helping with. Therefore, though there isn’t any significant impact of ultrasound on body repair, it is equally harmless to explore. It will be rewarding if you also be actively involved in rehabilitation through plans like routine exercise to ensure a safe and rapid recovery.