Lasers are regularly discussed in chiropractic trade publications, newsletters, conferences, and other places.
And there are many types of lasers that various medical specialties use. Lasers such as Excimer, Nd:YAG, and CO2 are not appropriate for therapy applications. Meanwhile, superpulsed, continuous wave (CW) pulsed, and combination superpulsed and CW lasers are regularly used in chiropractic offices for their therapeutic benefits.
Laser emission is either “on” or “off.” If the laser is constantly on and emitting light, then it is in continuous mode. If there is a time-on and time-off, then the laser is operating in pulse mode.
Regardless of mode, lasers work— among their other functions—by increasing adenosine triphosphate (ATP) synthesis in cellular mitochondria, activating the electron transport system, and many other biochemical and biophysical reactions in tissues and organs.
What is laser therapy used for?
Laser therapy has beneficial photobiomodulation effects for relieving pain, resolving inflammation, and increasing the speed, quality, and tensile strength of tissue repair. It has also been shown to stimulate the immune system, reduce infection, and improve the function of neurological tissue. Laser therapy is also effective in increasing collagen production, bone repair, reducing edema, increasing lymphatic drainage, and increasing production of capillary beds.
The amount of laser energy (joules) applied will vary dramatically between a CW pulsed laser and a superpulsed laser. For the same average power, superpulsed lasers will treat more quickly and penetrate more deeply into tissues than a CW laser. The technologies are different and are not directly comparable by measuring the total amount of joules delivered. Rather, the dosage (joules per cm2) at the target tissue is absolutely key.
The World Association for Laser Therapy (WALT) suggests a dosage at the target tissue of 4 to 10 joules per cm2.
There are thousands of superpulsed lasers in use around the world. The first laser classified as superpulsed was cleared by the FDA in 2004. The tech- nology is not as well-known as CW pulsed lasers. However, the deep tissue penetration and minimal-to-no thermal effects of superpulsed lasers are advantages when compared to CW pulsed lasers.
Superpulsed laser terminology
There is no consensus in the laser industry regarding the precise definition of a superpulsed laser. Two concepts are currently in use by laser manufacturers:
1. The peak power of a superpulsed laser is “significantly” higher than the average power. Clinical research supports the principle of a peak power significantly higher than average power. Peak power drives laser energy deep into tissues, with little to no thermal effects. WALT recommends one-fourth to one-half of the treatment time when using super- pulsed lasers, compared to CW pulsed lasers, for the same clinical conditions.Diode lasers of 904 nm to 910 nm are technically capable of producing much higher peak power to maximum average power ratios than other therapeutic wavelength diodes. But the issue of “significantly higher” peak power is currently open to interpretation—there is no current consensus as to whether simple multiples or orders of magnitude constitute “significantly higher” ratios of peak power to the maximum average power.
Typically, a ratio of 10 or higher is adequate for superpulsed lasers so that, for example, a superpulsed laser with 50 W of peak power should be capable of producing an average power of 500 mW.
2. Superpulsing is defined by the pulse rate. Several superpulsing lasers are capable of up to 100,000 pulses per second (Hz). Research by Karu suggests that higher pulse rates activate additional cellular mechanisms.1
Treatment considerations
If you want your patients to have minimal to no thermal effects or risk of tissue injury, and you want to treat deep tissues, consider a superpulsed laser solution. You will also be able to target specific acupuncture points, and there are fewer concerns about treating dark-pigmented skin.
Superpulsed lasers produce high power impulses of light for a brief duration to more effectively drive light energy deep into the tissues. There are little or no thermal effects in the tissue because the pulses are of extremely short duration, typically on the order of 200 billionths of a second per pulse.
Shorter treatment time. Superpulsed and CW lasers that have same average power (watts) deliver the same amount of energy (joules). However, according to WALT recommendations, the treatment time with superpulsed lasers is typically 50 to 75 percent shorter.
Option for unattended treatment. The minimal thermal effect allows you to keep a superpulsed laser in one place during a treatment session. An articulated arm permits the optimal placement of the laser handpiece.
Combining these two factors allows for unattended treatment, thus freeing up staff time.
Greater depth of tissue penetration. The wavelength of superpulsed lasers (904– 910 nm) and the high peak power drive energy deep into the body. By using superpulsed lasers, it is possible to effectively drive light energy deep into the tissue using an average power that can be much lower than that used with a continuous wave pulsed laser.
Comparing superpulsed lasers
The true way to measure lasers against each other is based on their average power, not peak power. The main therapeutic effects of a laser are based on the energy density or dose delivered through the handpiece to the target tissues, which is a function of its average power and the handpiece aperture.
Superpulsed lasers with low pulse repetition rates (pulses per second or Hz) have low average power.
Superpulsed lasers with adequate average power typically have pulse rates of 50,000 to 100,000 pulses per second.
The dose is directly related to both the highest amount of power that the superpulsed laser can generate (the peak power) and the pulses per second (Hz).
The average power can also be increased by coupling the best of both superpulsed and CW pulsed lasers in one beam. These types of lasers allow you to operate in
- Superpulsed mode only,
- CW pulsed only, or
- Superpulsed combined with continuous wave pulsed.
In cases where the laser contains a combination of superpulsed and CW diodes, total average power is not necessarily the sum of the separate average powers. One must ensure that the superpulsed diodes themselves have reasonably high average powers to ensure deep tissue penetration.
When superpulsed and continuous wave lasers are combined they penetrate even better because the CW laser “rides” the superpulsed beam for greater penetration than it would normally achieve by itself.
Nelson Marquina , DC, PhD, is the president of USA Laser Biotech Inc. and a developer of biophotonic and bioelectromagnetic systems and treatment protocols. He is also certified by the Virginia Board of Medicine to practice acupuncture.
Rob Berman is a partner at Berman Partners, LLc, a medical device sale, service, and marketing company. Berman Partners specializes in new and preowned therapeutic lasers. he can be contacted at 860-707-4220, rob@bermanpartners.com, or through bermanpartners.com.
Reference
1 Karu T. Mitochondrial mechanisms of photobiomodulation in context of new data about multiple roles of ATP. Photomed Laser Surg. 2010;28(2):159-60.
