Friday, May 23, 2008

Laser Treatment for Port-Wine Stains

I'm taking this from an article by Robert Tomaino that was in the December 2007 issue of "Branching Out", a publication of The Sturge-Weber Foundation.

"What is the best technique or laser device for the treatment of port-wine stains (PWS)?"

J. Stuart Nelson, M.D., Ph. D., Medical Director of the Beckman Laser Institute and Medical Clinic at the University of California, Irvine, hears this question more than any other. His response?

"There is no one laser device that works well for all PWS patients."

PWS is highly heterogeneous, which means that each PWS is dissimilar or unique. The abnormal blood vessels that make up a PWS will vary in size, diameter, distribution, and depth. This is true even with different affected areas on the same patient. Therefore, the most effective therapy for one person will not be the same for another. It may also be true that one type of laser may be effective against certain blood vessels in a person while a different laser may be more effective against other blood vessels in that same person.

Although there is no optimal therapy or laser device for all PWS, through advancements in technology, the practice of using multiple lasers on one patient, varying the wavelengths and pulse widths and better cooling techniques, researchers have greatly improved the treatment of these lesions over the last 10-15 years.

When discussing the state of laser therapy for PWS, it is important to understand how lasers can effectively treat skin abnormalities. Lasers eliminate a vascular lesion such as PWS by destroying the abnormal blood vessels that make up the lesion. Lasers can selectively destroy tissue or cells in the body based on their color of light, which is known as the wavelength. Because a certain light absorbing molecule in the skin called a chromophore may absorb another color well, the color of a laser and the color of the specifically targeted tissue to determine whether the laser light is absorbed.

At Dr. Nelson's institute, the use of lasers that produce a yellow beam of light is preferred. Yellow is well-absorbed by things that are red such as hemoglobin, the protein that gives red blood cells their red color. Yellow lasers pass through the superficial layers of skin, enter the targeted blood vessels and heat up the hemoglobin eventually destroying those blood vessels. The body will then reabsorb the remains of the blood vessels.

Although lasers pass through the superficial layers of the skin, they can still cause some residual damage to the skin. As a way to preserve and protect the skin from harm, various cooling techniques are used. Improved cooling techniques allow the superficial layers of skin to remain cooler longer, while the temperature of the underlying abnormal blood vessels remains the same. This allows for a greater amount of energy to be delivered to the target area resulting in the need for fewer treatment sessions.

Pulsed dye laser therapy is now the standard for treatment of individuals with PWS. With this therapy the laser beam is delivered in short, quick bursts, or pulses. The length of time the laser beam is on is called the pulse duration. At Dr. Nelson's institute, individuals are often treated with multiple laser devices during the same treatment session.

By using multiple devices, Dr. Nelson can treat the different vessels that can make up a PWS. Shorter pulse durations and wavelengths are better for superficial lesions usually marked by a light pink color and smaller vessels. Longer pulse durations and wavelengths are more effective for deeper lesions, which are usually marked by a dark purple color and larger vessels.

The use of multiple lasers and other advances in therapy target the heterogeneous natures of these lesions. No two PWS are the same and therefore the treatment from one individual to another should not be the same.

"We've seen much better results," said Dr. Nelson of the use of multiple lasers, which helps patients obtain as much fading as possible.

Although the options for laser therapy for PWS have improved dramatically in the last several years, researchers are still seeking to further improve the technology and address remaining issues such as the potential redarkening of treated lesions.

A recent article in the New England Journal of Medicine discussed the redarkening of PWS over a 10-year period. However, the article may better serve to illustrate how far the treatment for these lesions has come. Dr. Nelson and Dr. Roy Geronemus of New York University Medical Center wrote a response to the article citing that the study used (now) outdated technology and did not utilize advances in other areas including dynamic cooling, varying pulse widths, higher energy densities and larger spot sizes.

Dr. Nelson explained that in the study the researchers used only one laser device so it is quite probable that many abnormal blood vessels such as those lying deeper in the skin were completely unaffected by the original treatment. If affected vessels are missed during the original treatment, they will re-grow insidiously over 5-10 years, eventually causing the area to redarken.

Finding ways to better treat those deeper lesions is one of the focuses of the research into PWS treatment. Dr. Nelson is working with the Sturge-Weber Foundation in getting approval from the Food and Drug Administration (FDA) to conduct clinical trials on topical angiogenesis inhibitors to prevent blood vessel formation (angiogenesis) after laser therapy.

Topical angiogenesis inhibitors are drugs applied directly to the skin (as in a cream) that work to prevent new blood vessel formation in the treated areas. These drugs have been successful in animal models, but the FDA has yet to approve studies in humans.

"I'm cautiously optimistic that in six to twelve months these drugs will enter into clinical trials," said Dr. Nelson.

Researchers are also working with a device called pulsed photothermal radiometry that allows them to see what is occurring beneath the surface of PWS. Information gathered from this noninvasive procedure can then be used to better plan an individual's treatment.

"Know your enemy," says Dr. Nelson referring to the military adage often attributed to Sun Tzu, a Chinese general and warrior from 500 B.C.

There will never be a one-size fits all solution for PWS treatment. However, as researchers continually learn more about these lesions, new discoveries will to continued advances in technology and, ultimately, more options for individuals and families seeking treatment.




If you would like help with research and investigation funding for PWS and Sturge-Weber Syndrome, you can donate to the Sturge-Weber Foundation by clicking 'donate' on the FirstGiving Widget at the top of the side bar to the left.

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