Description of Intervention
Therapeutic ultrasound is a physical modality commonly used by physical and hand therapists to relieve pain and promote tissue healing. It involves the application of longitudinal sound waves generated by a transducer head to a target area, which penetrate soft tissues and causes vibrations that induce both thermal and nonthermal physical changes within these tissues.1,2 Phonophoresis, also known as sonophoresis or ultrasonophoresis, is a technique in which therapeutic ultrasound is used to introduce pharmacological agents through the skin into deeper subcutaneous target tissues to alleviate pain and inflammation.3,4
Medications typically used in phonophoresis include corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs), and local anesthetics, which are intended to elicit immediate pain-relieving effects as the drugs are absorbed transdermally.5,6 The advantages of transdermal drug delivery include easy titration and dose adjustment, lack of painful injections, and avoidance of hepatic first-pass metabolism.6 In addition, phonophoresis combines two interventions known to be effective for reducing pain—therapeutic ultrasound and medications—which may provide additional benefits compared to the use of either intervention individually.3,4 Phonophoresis can thus be regarded a safe and painless alternative to injections for the treatment of many painful musculoskeletal conditions in the upper extremity.4
Several parameters of the ultrasound unit used in phonophoresis can be adjusted depending on the location of pain and other variables. These include frequency, duty cycle, wavelength, energy, power, and intensity, which determine how the sound waves are transmitted, attenuated, and reflected through the tissue.7
Indications for Intervention
Phonophoresis is indicated for any musculoskeletal condition that leads to pain and/or inflammation in the hand, wrist, or elbow. Patients recovering from surgery in these regions may also be candidates for phonophoresis.
Diagnosis
- Ask the patient to describe their medical history, including any recent injuries to the hand/fingers, wrist, or elbow, or any recent surgeries performed.
- Ask if the patient has any comorbidities, including smoking, diabetes, or osteopenia.
- Perform a physical examination of the area of interest. If range of motion (ROM) is impaired, measure the active and passive ROM of any involved joint(s) and compare these measurements to the contralateral side.
- Ask the patient to rate their pain on the visual analogue scale (VAS) or a similar outcome measure.
- Consider using the DASH (Disabilities of the Arm, Shoulder, and Hand) questionnaire to evaluate the patient’s subjective impairment of the upper extremity.
- If the patient presents with pain anywhere in the upper extremity, consider utilizing Phonophoresis.
Intervention Options1,3,5,8
In most cases, phonophoresis should be integrated into a comprehensive, individualized treatment program designed by a physical therapist or hand therapist. Depending on the patient’s diagnosis, the program may also include strengthening exercises, stretching exercises, manual therapy, functional training, and/or other therapeutic modalities to alleviate symptoms and increase physical function.
Prior to initiating phonophoresis, ask the patient to remove any clothing to expose the skin of the target area and inspect the skin for any infections, burns, or active wounds. If the skin is clear, first apply the medicated ointment or gel to the target area. Some of the most frequently used medications in phonophoresis are the corticosteroids betamethasone, hydrocortisone, and dexamethasone, the NSAIDs benzydamine, piroxicam, and ketoprofen, salicylates, and other anesthetics. Dexamethasone is known to work particularly well in phonophoresis. Next, apply ultrasound gel over the same area as the topical medication (some products include both the medication and ultrasound gel, in which case only this gel needs to be applied). The subsequent treatment steps of phonophoresis treatment are listed below:
- Set the ultrasound unit to the appropriate parameters, including frequency, power, wavelength, and intensity
- Phonophoresis can either be delivered at a high frequency and intensity or a low frequency and intensity
- Using a low frequency (eg, 20 kHz) and intensity (eg, 125 mW/cm2) is preferred because it helps to deliver medication to the tissues more efficiently, but not all ultrasound units can be set to these parameters
- If a low frequency and intensity cannot be set, use a higher frequency (e.g., 3 MHz) and intensity (0.5–1.0 W/cm2)
- Consider starting at 0.5 W/cm2 and then assessing how the patient feels; if the patient tolerates the intensity, you can increase it to 1.0 W/cm2
- Apply the transducer head of the ultrasound unit to the skin in a slow, circular motion (about 1 second per rotation) continuously for 5–10 minutes; in some cases, a longer duration may be needed
- The treatment area should be about two times the size of the ultrasound transducer
- NOTE: always keep the ultrasound transducer head moving
- After completing the session, wipe the gel or cream off the target area
Phonophoresis may be used in a therapy clinic several times per week, but usually only once per day. Be sure to regulate the patient’s comfort level during treatment and adjust the parameters if necessary.
