Therapeutic Ultrasound – What is it?
Ultrasound is maybe the most used, or should I say ‘abused’, form of electrotherapy in physiotherapy clinics. Almost everyone that has attended a physiotherapist would have had a strange, metal stick rubbed on their skin covered in a strange blue gel. Why do we do this? Well let me explain.
The term electrotherapy simple relates the use of electrical energy to treat medical issues. Examples in current medical practice include muscle simulator machines, TENS and iontophoresis. Ultrasound is grouped within the ‘electrotherapy’ family, however does not actually use electrical energy to treat, but rather mechanical energy, or more specifically sound waves.
The strange stick that is rubbed on the skin over your injury is producing sound waves at an incredibly high frequency, above what the human ear can detect, and therefore is termed ultrasound. These sound waves are transferred into your tissue through some form of medium, often a blue gel, as air will cause them to be reflected. Once within your body the waves will become absorbed by any tissue high in protein contact (i.e. bone, scar tissue, ligaments and tendon), forming tiny bubbles around the tissue cells (cavitation). These bubbles will then start to vibrate, causing cells around the site to become excited and increase there functioning.
Physiotherapists use US as it is ‘pro-healing’, meaning the aim is to increase the functioning of tissue cells in and around injured tissue, thereby accelerating healing and ensuring the tissue heals optimally. Therefore based on what we now, it may be effective in treating various injuries such as:
- Scar tissue (or the reduction of)
- Ligament strains
- Bone (you need a very specialized machine for this however)
Notice muscle injuries are not included in this! That’s because muscle is full of blood, and therefore water, so is generally a poor absorber of sound waves. It may be used for scar tissue within the muscle, but its effectiveness for muscle injury is pretty lacking.
Does it work?
Well as with a lot of medical treatments the research is conflicting. When using the gold standard of scientific research methods, the random controlled trial (RCT), US does not show significant improvements in treating common injuries. However, at the cellular level in a laboratory, it does what it says on the tin. Potential reasons for this are that testing on humans lends itself to many factors which are hard to control. Such as patient expectations, beliefs and even personal healing times. Therefore, comparing one patients healing time to another is terribly difficult. My personal opinion is that it is worth using in certain situations. My personal belief; it is massively overused by physios who sometimes just use it as they have nothing else to offer!
I hope you liked this article. Remember this is my personal interpretation and opinion on the subject matter. For more in-depth information on the subject may I suggest reading Tim Watson’s work at Electrotherapy