Dallas — The lasers that first entered the medical and cosmetic arena more than 35 years ago operate in much the same way and achieve similar effects as today's lasers, according to Lars Hode, Dr.Sci., a physicist specializing in laser medicine, and president and founder of the Swedish Medical Society, Stockholm.
"It is the same mechanism behind the stimulated hair growth and accelerated wound healing reported in 1968, and the wrinkle reduction of today's methods," Dr. Hode says. He offered his historical insight in a presentation at the American Society for Laser Medicine and Surgery, here.
"Basically, the same kind of problems are being treated, but the effects are more obvious," Dr. Hode says.
Past and present
Dr. Hode says the first reported laser therapy results from 35 years ago were from a research team in Hungary's Semmelweiss Hospital who called it "laser biostimulation." The team observed how certain doses of laser light could stimulate hair growth and wound healing, and activate leukocytes. They used a ruby laser, but later HeNe lasers were employed by medical and paramedical personnel because they also have a red light and are just as highly coherent as ruby lasers, but without the extreme expense.
Studies on cell cultures, animals and humans have shown that laser light can influence several functions in cells and tissue, a complex process known as photo biostimulation. (Graphic courtesy of Lars Hode, Dr.Sci.)
Thirty years ago, a German team that tested different laser light doses on ulcers in animals found that doses of up to 10 J/cm2 prompted faster healing, while doses of 20 J/cm2 had a retarding effect. At the same time, Canadians found laser beams to have similar effects as needles in acupuncture, Dr. Hode says.
Five years later, lasers were shown to have a positive effect on rheumatoid arthritis. In the meantime, HeNe lasers were used more frequently in Russia for therapeutic stomatology.
Twenty years ago, European cosmeticians called their tools "soft lasers" and used them to treat acne vulgaris and facial wrinkles and scars. The lasers they used had power as low as in the milliwatt range. The effect was named skin rejuvenation.
Today, researchers know that light from many other light sources can influence biologic systems in a similar way. Also, the light emitting diodes (LED), with their relatively narrow-spectrum, high-spectral intensity but non-coherent light, show effect on wrinkles. During the past three years, flash lamp devices with very high light fluxes also have been shown to affect wrinkles. Even radio waves can be used.
"One factor they all have in common is they can all stimulate certain cell and tissue functions," Dr. Hode points out. Originally, this was called laser biostimulation, but today is given the more proper name of photobiomodulation.
During the past 10 years, CO2 lasers and laser peels have gained popularity for treating wrinkles and acne scars. The somewhat milder Er:YAG laser was also found to improve rhytides. But this method of skin ablation is rather painful.
During the past five years, the advent of nonablative skin rejuvenation signified the ability of lasers to improve wrinkles and scars without burning or pain. The mechanism behind this is biostimulation.
More recently, within the past year, a single treatment with a pulsed dye laser has improved acne in the inflammatory phase. The reason is not that the 585 nm wavelength kills bacteria, but that biostimulation influences the local immune defense. Acne has also been successfully treated with ruby and KTP lasers by Stockholm clinicians.
By compiling a presentation that gave a look back at the initial lasers and compared them to today's modalities, Dr. Hode hoped to encourage attendees at the meeting of the American Society for Laser Medicine and Surgery to consider laser therapy when they might not otherwise.