Comparison of Hands-free Ultrasound and Traditional Ultrasound for Therapeutic Treatment
Melanson H., Draper DO., Mitchell UH., Eggett DL. Athl Train Sports Health Care 2016;8(4):177-184
Take Home Message: A hands-free ultrasound unit at 1 MHz failed to increase the temperature deep in the gastrocnemius after 10 minutes.
Therapeutic ultrasound is an effective deep heating modality (heating to a depth of ~2 to 5 cm) when used properly. Traditional ultrasound treatments are labor intensive, time consuming, and prone to clinician error (e.g., treating too large an area, moving the sound head too fast). There is a hands-free ultrasound unit; however, there is little research whether the hands-free unit produces the same deep heating effects as traditional ultrasound. Therefore, the authors conducted a randomized cross-over experiment with 16 healthy participants (6 males and 10 females, age ~22 years, average gastrocnemius subcutaneous fat thickness ~0.85 cm) to determine whether the Rich-Mar AutoSound would be as effective as a traditional ultrasound at increasing the temperature of the gastrocnemius muscle during a 10-minute, 1 MHz, 1.0 W/cm2 treatment. Each participant received the treatment over their left gastrocnemius with both the hands-free and traditional ultrasound unit with 24 hours between treatments. The treatment area was two times the size of the ultrasound heads. The authors measured the participants’ muscle temperature every 30 seconds during the ultrasound treatments using a thermistor inserted ~2.25 cm deep in the triceps surae muscle. The depth was verified with ultrasound imaging. The authors found that the hands free ultrasound was not effective at increasing the temperature of the gastrocnemius muscle because temperature decreased 0.16°C during treatment. The traditional ultrasound had a total temperature increase of 0.41°C (rate of warming ~ 0.025°C per minute).
This is an important study because as technology advances and more instruments come on the market it is necessary to test them and have evidence to support the purchase and implementation of a new device into practice. The authors of this study demonstrated that the hands-free ultrasound device was not effective for heating deep tissues at 1 MHz. They suggested that the hands free device failed to deliver a beneficial heating effect due to the location and activation of the 4 crystal heads and the use of 10-mm thick gel pads (previous research demonstrated that 2- to 3-mm gel pads are more effective). The traditional ultrasound treatment increased the gastrocnemius temperature but it was likely insufficient for clinical benefit. Medical professionals should be aware of the effectiveness of their tools as well as the reliability and validity of their own technique in handling the device. It would be interesting to see this study repeated in an injured population with damaged tissue to evaluate the outcomes related with the ultrasound units. For example, it is unclear how the placebo effect differs between a clinician provided ultrasound treatment versus a hands-free treatment. Lastly, medical professionals need to work with manufacturers to produce and evaluate products before they are available on the market. As Christopher Ingersoll described in It’s Time For Evidence, it is not the manufactures responsibility to provide us with research to support their product’s clinical effectiveness. It is our job as medical professionals to see how effective these devices are within our respective roles and populations.
Questions for Discussion: Do you use ultrasound as a deep heating modality? If so, do you find it to be effective? Would you be interested in a hands-free ultrasound device?
Written by: Jane McDevitt, PhD
Reviewed by: Jeff Driban
Related Posts:American Medical Society for Sports Medicine (AMSSM) Position Statement: Interventional Musculoskeletal Ultrasound in Sports Medicine