Lighting the way in laser skin surgery

November 11, 2007

The concept that revolutionized laser surgery and earned UC Irvine more than $40 million came to Dr. J. Stuart Nelson in 1992 while he was watching a baseball game.

In the early 1990s, surgeons like Nelson were trying to adapt laser technology for medical use, and the Beckman Laser Institute & Medical Clinic was an epicenter for this effort. It was, at the time, the only facility in the world to house basic science and engineering labs and an outpatient clinic under one roof, letting researchers and surgeons quickly translate findings into patient-care breakthroughs.

As medical director of Beckman, Nelson had strived to improve laser treatments for disfiguring vascular birthmarks, such as port-wine stains, in infants and young children. Lasers were of limited use because their intense light also injured the fragile top layer of skin, causing pain, scarring and pigmentation changes. The challenge was to find a way to protect the outer skin while maximizing the laser's capacity to destroy the deeper blood vessels that create a birthmark.

Nelson and his colleagues—postdoctoral researcher Thomas Milner and visiting Norwegian engineer Lars Svaasand—had tried using ice cubes, running cold water and even the application of chilled metal plates to cool the skin's superficial layer before laser exposure. Unfortunately, all these methods proved too cumbersome and, more important, also cooled the targeted blood vessels, which inhibited the laser's effectiveness.

"We needed to get something very cold onto the skin surface in perfect thermal contact and then off the skin surface—all within a fraction of a second," Nelson says. "I remembered what I saw watching a baseball game."

Over a Friday night dinner at the former Rusty Pelican restaurant in Irvine, he told his colleagues how, when a batter fouled a baseball off his foot or ankle, a trainer would emerge from the dugout and spray ethyl chloride onto the injury site to numb the pain. The three agreed that spray cooling might be effective if the cryogenic agent evaporated very quickly and, therefore, only affected the topmost layer of skin.

During the weekend, Milner and Svaasand hashed out ideas on how to make this concept work; on Monday, they went to Pep Boys and purchased a Toyota Camry fuel injector valve, a hose clamp and air-conditioning coolant to build the first prototype of the Dynamic Cooling Device.

"It was a fairly simple construction," says Milner, currently the Marion E. Forsman Centennial Professor in Engineering at the University of Texas at Austin. "That's the beauty of the invention: It's so simple and works so well."

The device is incorporated into the laser's hand piece and sprays a nonflammable, environmentally compatible freon substitute onto the skin surface, forming a liquid pool with a temperature of minus 60 degrees Celsius. This pool evaporates almost immediately and milliseconds later, the skin is exposed to the laser. The process is repeated before each pulse of light.

"Because the spurt durations are so short, the cooling remains confined to the skin's most superficial layer and does not affect the deeper targeted blood vessels causing the vascular birthmark," Nelson explains. "This allows much higher laser light dosages to be used, while at the same time minimizing injury to the skin and pain to the patient."

The DCD was patented in September 1998 and subsequently licensed to Candela Laser Corp. for commercial development and marketing. It's now standard on more than 20,000 Candela lasers sold worldwide, as well as on the lasers of other companies that have sublicensed the technology.

Between 2001 and 2010, the device was among the 10 top-earning licensed inventions in the University of California system—and in 2005 and 2006, it ranked second and third, respectively. To date, the DCD has generated more than $40 million in royalties for UC Irvine, of which almost $7 million has been returned to the institute.

"The combination of basic research, engineering and clinical testing that went into the Dynamic Cooling Device is exactly what was envisioned over 30 years ago when the idea of the BLIMC was first conceived," says Michael Berns, the Arnold & Mabel Beckman Chair in Laser Biomedicine and institute co-founder.

While DCD-equipped lasers are used for many cosmetic procedures—the removal of unwanted hair, scars and rosacea, for example—Nelson is pleased that his invention primarily benefits individuals born with port-wine stains. At Beckman's world-renowned Vascular Birthmarks & Malformations Diagnostic and Treatment Center, he has handled more than 10,000 such cases.

Every other year, the center—in conjunction with the Vascular Birthmarks Foundation—hosts a conference at which families dealing with vascular birthmarks meet with researchers and surgeons in the field to discuss the latest findings and breakthroughs.

Nelson says such events—where he is able to interact with new, current and former patients—remind him of the DCD's impact.

"The technology has made possible the early, painless, safe and effective treatment of port-wine stains and other disfiguring vascular birthmarks in infants and young children in ways that Tom, Lars and I could never have imagined," Nelson says. "That's what I'm most proud of."

—Tom Vasich, University Communications

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