A paper titled ”The Effectiveness of Therapeutic Class IV (10 W) Laser Treatment for Epicondylitis” [ref] showed that 10 Watt Class IV laser (mixed 8W 970nm, 2W 810) was successful in reducing pain and improving function in an RCT with 15 patients, and that there was good statistical significance at 6 months following a course of 6 treatments.
The claim by class IV laser manufacturers is that class IV lasers are better (faster, deeper and more effective) than Class 3b and LED systems. Conversely the 3B laser and LED manufacturers argue that less power density is more effective because delivering energy too quickly can overdose tissues and class IV lasers might burn the skin.
Throughout this paper there are marketing messages claiming the advantages of shorter treatment times than low power LLLT systems and of course the title shouts “10 Watt Class IV laser” just in case the reader is in any doubt that more power is what you need.
Regular readers of this column know my obsession with irradiation parameters, particularly dose rate effects (W/cm2) and will not be surprised to learn that I deconstruced the irradiation parameters used in this trial . Surprise, surprise they were the same low irradiance levels typically used by 3B lasers and LED systems, if not less and the treatment time was longer too.
Yes, it was a 10 Watt laser and yes, 3,000 joules was delivered, however it had a large beam area and treatment was delivered over (45cm2) in a “painting fashion”. The fluence (dose) was 6.6 Joules/cm2 and the power density was a tiny 22mW/cm2, consequently treatment time was a hefty 5 mins.
The average irradiance was not disclosed in the paper and the reader is directed to think that more power is quicker.
P.S. research trials with 3B lasers are typically 30 seconds to 3 mins and our recommended treatment is 1 min with a large LED cluster to the lateral epicondyle and 30 seconds for any related trigger points.