In addition to Geoff's message, here are (again the conclusions and) the
hyperlinks to the studies referred to:
Robertson and Baker did a systematic literature review of RCTs done one the
effect of US. Their conclusion: out the 10 methodologically acceptable
studies, 8 said that there was no effect, and only 2 said that there was:
http://www.ptjournal.org/PTJournal/July2001/v81n7p1339.html (full text is -
still - available).
Assuming all reviewed studies applied the US according to a normal clinical
treatment plan (that is, 2 or 3 times a week, maybe even 5, and not twice
daily), it would in my opinion be a very unwise thing to defend US, to
demand that it should remain reimbursed, and/or to charge it to patients or
insurance companies. It would be detrimental to our credibility.
Maybe US works if it is applied twice or thrice daily. That would however
only make it suitable for sports teams with PTs on the pay roll, who would
then have to have enough time. But not for general daily practice, in my
opinion.
They (and Duck) also did a literature review on the biophysical aspects.
Their conclusion: "This review reveals that there is currently insufficient
biophysical evidence to provide a scientific foundation for the clinical use
of therapeutic ultrasound for the treatment of people with pain and soft
tissue injury.":
http://www.ptjournal.org/PTJournal/July2001/v81n7p1351.html.
R.,
Frank Conijn, PT
The Netherlands
----- Original Message -----
From: "Geoff" <[log in to unmask]>
To: <[log in to unmask]>
Sent: zondag 19 augustus 2001 7:51
Subject: Re: Ultrasound
Regarding this subject, I would direct you all to two meta-analysis articles
published in the July (?)issue of Physical Therapy. The authors demonstrate
through their analysis of the literature that not only is there no proven
physiologic effect of ultrasound in living human tissue, but that there is
also no evidence to show efficacy in any patient population.
As to the notion that energy is applied so tissue changes must occur, there
is no evidence to support that US has an effect in muscle tissue.
A friend of mine performed an experiment at Sandia National Laboratories
with a research doctor there. They developed a muscle and bone model out of
substances chosen to acoustically mimic actual muscle and bone tissue. They
then applied ultrasound at the usual paramenters for several minutes and
then thermographed the models.
They found that the attenuation of US energy in muscle at 1 and 3 MHz was
nearly nill. The greatest attenuation occured at the surface of the "bone,"
thus explaining the "thermal effects" felt by many patients (i.e. the
sensation most patients feel from ultrasound, if any, is the attenuation of
sound energy at the periosteum... which is much more sensate than muscle
tissue). However, the lack of attenuation of energy in the muscle model
means that since very little energy is transferred here, very little effect
would be seen.
This may also include "non-thermal" effects such as cavitation. To date, no
study I'm aware of demonstrates cavitation effects of ultrasound in vivo.
The one area where effects can be seen is at the granular layer of the
epidermis. Here, ultrasound produces profound changes in the permeability
of the tissue. Thus, medication is more easily transmitted through the skin
(i.e. phonophoresis). The problem is, if you are using hydrocortisone cream
(the medication of choice), you are blocking all US energy from reaching the
skin as creams do not transmit sound energy well. You also need to allow
the medication time to absorb so standard application times need to be
lengthened past the US treatment... but I digress.
Check out the articles! They are good reads.
Warm regards,
Geoff Mosley, PT, NCS
MRC
Mt. Vernon, MO
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