Procedural laser knowledge crucial to patient, practice

New Orleans - If dermatologists know which lasers target the lesions and skin areas they are most likely to treat, they can avoid buying multiple lasers with overlapping capabilities, according to Suzan Obagi, M.D., who presented her findings here at the annual cosmetic surgery symposium of the American College of Oral and Maxillofacial Surgeons.

"Many dermatologists graduate from training programs with little or no training in lasers."

"Don't just ask the salesperson," she says. "Actually learn the physics behind the lasers so you can ask the correct questions and set them correctly for your patients and minimize complications."

The plethora of information includes, but is not exclusive to, laser courses, textbooks, online searches and presentations and training courses. In addition, the various laser companies often can refer dermatologists to colleagues who are experts on different lasers. "I have seven different lasers and I let any physician visit and learn to operate them," she says. An immersion into several modes of learning will create a synergy that maximizes retention of the information, she says.

In her presentation, she discussed the appropriate lasers for different lesions as well as issues of laser safety.

Different wavelengths, different targets The general principle for a dermatology practice is that the practice's lasers need to have wavelengths that are appropriate for the tissues typically treated by a dermatologist. Hemoglobin, melanin and water require different wavelengths, although several lasers have adjustable pulse widths, Dr. Obagi says.

Lasers that treat vascular lesions, obviously, target hemoglobin.

"Smaller, lighter, superficial lesions are typically treated by a 532 nm potassium titanyl phosphate (KTP) laser, a 585 nm or 595 nm pulsed-dye laser, or a diode laser," she says. "For larger vessels that are purple to blue in color, a diode laser or Nd:YAG would be preferable, because you need a longer wavelength to reach that depth."

The appropriate lesion to target the melanin in pigmented lesions will vary depending on the depth of the lesion, she says. If the lesion is superficial, a 532 nm KTP laser would be appropriate, as would a frequency-doubled, q-switched Nd:YAG laser. Deep-seated lesions, such as tattoos, dermal melasma, nevus of Oto should be treated by q-switched lasers, including the alexandrite, ruby, or Nd:YAG modalities.

"The laser energy needs to penetrate deeply enough to blast that pigment," Dr. Obagi says. "If you're trying to kill two birds with one stone, you may want to try light-based systems that use cut-off filters to treat both at once, such as intense-pulsed light systems. However, remember that these have a higher margin of error. Also, before you use these systems, you should make sure that your training is adequate, because these systems have a slightly higher incidence of causing burns."

When water is the target, as with resurfacing procedures, lasers with an infrared wavelength would be appropriate, she says. These include the 1340 nm Nd:YAG, the 1450 nm long-wavelength diode, and the 1450 nm erbium glass.

"The premise is to heat up the collagen layer just shy of causing a blister," Dr. Obagi says. "This treatment will trigger the healing process."

The biggest problem when laser treatments go awry is an incomplete understanding of the targeted lesion and the adjacent tissue, she says. For example, the laser chosen to treat a red spot may also burn the patient's skin if the patient has been tanning.