Lasers in Dermatology

[madman]

INTRODUCTION AND HISTORY

The history of laser medicine starts with Albert Einstein’s theory of stimulated emission, introduced in 1916. He postulated that when excited molecules/atoms interact with each other, they are able to stimulate the emission of new photons that are of a similar frequency, phase, and direction as the original atoms/molecules. This concept was used by early physicists, including TheodoreMaiman, to develop the earliest lasers. In 1963, Dr. Leon Goldman, a pioneer in laser medicine, first used a laser on human skin to treat melanoma. Dr. Goldman also used the continuous wave CO2 and argon lasers to treat port wine stains. 1 Although the lesions he treated lightened, they had high rates of scarring and complications due to the non-selective nature in which the laser energy was absorbed in the skin. The theory of selective photothermolysis, as elucidated by Drs. John Parrish and Rox Anderson propelled the use of lasers and forever changed the field of dermatology, and other medical specialties.2 The concept of selective photothermolysis refers to localized, “selective,” destruction of the desired target by combining a selective wavelength that is absorbed by the target chromophore and a pulse duration that is equal or shorter than the thermal relaxation time of the target chromophore. The combination of these 2 notions allows for more precise control of thermal energy and allows for more focused destruction. With the advent of selective photothermolysis, the treatment of unwanted pigment, tattoos, and hair became possible. We went from non-selective lasers to early versions of both ablative and non-ablative lasers. Additional applications became possible with the advent of fractional photothermolysis.3 The laser beam can be applied fully to the tissue, or it can be delivered in a pixilated pattern, called fractional photothermolysis (FP). FP can use both ablative and nonablative wavelengths of light. This fractional injury is seen in the form of microscopic treatment zones (MTZ) that often form a grid pattern of injury on the skin. This allows for the sparing of normal tissue between each MTZ, and a shorter treatment recovery time. Interestingly, up to 50% of the tissue can be destroyed during FP without causing scarring or necrosis. By creating multiple laser holes in the skin, FP has been also used as a new method for drug delivery. This expansion continues with advances in technology and technique. Herein, we provide a review of updates in lasers as they are used in dermatology to treat a variety of medical and aesthetic conditions.




*Vascular Lasers

*Hair Removal

*Tattoos

*Pigmentation/Pigmented Lesions

*Scars




*New Devices

Although there have been so many recent advances and updates in laser technology and its applications, there are continually new devices and applications in the pipeline. One promising development is a newer 3-dimensional (3D) laser that has been FDA-cleared and will be commercially available in the United States soon. This 3D laser is highly focusable allowing laser energy to be targeted at precise depths in the dermis with reduced fluences at the epidermis. The reduced energy at the epidermis will make this a safer device for the skin of color patients. Additionally, there will be a high-resolution, high-speed imaging system that will be paired and integrated with the laser. This imaging system will not only allow mapping and guidance during treatment but also pretreatment and post-treatment skin changes to be archived, making way for a more personalized laser treatment for every patient.

Other devices modifications that may be on the horizon in the future include the integration of robots into dermatology. These laser “robots” may be programmed by humans, however, the action itself will be executed by robot software. Such a laser “robot” may be useful in skin cancer surgery, where we can perform image-guided laser ablation. Another way to integrate robots into lasers may be fractional-laser robots. These laser robots may be able to penetrate the skin at any precise depth and target several imageable structures such as sweat glands, nerves, cells, tumors, etc. These ablative fractional robot lasers may even be used for very precise drug delivery. The future remains very bright when it comes to the emergence of new technology that will advance our ability to treat a variety of medical and cosmetic dermatologic conditions.

 

[madman]

CLINICAL CARE POINTS

*Port wine stains typically take numerous treatments to lighten and complete removal is often challenging. Treatment should be initiated as early as possible as infants tend to respond better than adults.

*Treating within the bony orbit requires the use of eye shields to protect the retina. While hemoglobin is the target chromophore, melanin is present in the retina and it also absorbs energy from most vascular lasers.

*Conditions such as rosacea can be treated with non-purpric settings and typically entail minimal downtime but require a series of treatments to bring about improvement.





Fig. 1. Before and after 4 treatments of a port wine stain in an adult patient with a 595-nm pulsed dye laser. (Courtesy of Dr. Omar Ibrahimi.)

Fig. 2. Before and after 4 treatments for rosacea with a 595-nm pulsed dye laser. (Courtesy of Dr. Omar Ibrahimi.

 

[madman]

CLINICAL CARE POINTS

*Patients should be counseled that on average 15% of hairs will be removed with each laser treatment and treatments should be spaced about 6 to 8 weeks apart to allow hairs to properly cycle through the various growth phases.

*Avoid treating within the bony orbit, including the glabella, due to the high risk of retinal damage (the retina contains melanin-dense tissues).

*Be careful to keep the handpiece perpendicular over convex and concave surfaces to ensure that the laser energy and any skin cooling methods are being delivered uniformly and will help avoid complications.





Fig. 3. Before and 15 months after 3 laser hair removal treatments in the axillae of a patient with a 1060-nm device. (Courtesy of Dr. Omar Ibrahimi.)

Fig. 4. Before and after 3 treatments of laser hair removal of the upper lip with a 755-nm device. (Courtesy of Dr.Omar Ibrahimi.)

 

[madman]

CLINICAL CARE POINTS

*Laser tattoo removal requires matching an unwanted tattoo ink color to its complementary laser wavelength.

*Picosecond lasers are an improvement that has led to faster and better clearing of tattoos but most tattoos still fall short of complete clearance.

*Be cautious when treating a multicolored tattoo in the skin of a color patient as melaninis are targeted by many of the laser wavelengths used and can result in significant depigmentation and hypopigmentation.

*Newer, professional, and single-ink color tattoos (ideally black) are easier to fade with laser treatments.

*The use of fractional ablative, repeat treatments, PFD patches, and rapid acoustic pulses may enhance and speed up laser tattoo removal.

*Never use a long pulse laser or an intense pulsed light (IPL) for tattoo removal, even if the device has the right wavelength for the color of the tattoo.




Fig. 5. Before and after 22 laser tattoo removal treatments with a 1064-nm picosecond device. (Courtesy of Dr.Omar Ibrahimi.

Fig. 6. Before and after 22 laser tattoo removal treatments with a 1064-nm picosecond device. (Courtesy of Dr.Omar Ibrahimi.)

 

[madman]

CLINICAL CARE POINTS

*A proper evaluation of the pigmented lesions needed prior to any laser treatments, ideally with dermoscopy.

*Lasers are not a first-line treatment for melasma. Melasma should be carefully evaluated and treated with first-line standard-of-care treatments to help stabilize pigment formation.

 

[madman]

CLINICAL CARE POINTS

*Vascular lasers and fractional lasers (ablative and non-ablative) can treat a variety of scars with success.

*Be careful about laser parameters when treating scars. Treating at lower densities and higher pulse energies (depth) is safer for scars.

*It is never too late to initiate laser treatment for scars, though earlier treatment is better. Lasers can be implemented as early as right after wound formation. Complete epithelialization is not necessary to initiate laser treatment of scars.

*Although ablative fractional lasers can be used in darker skin types, one must tread with caution. In some circumstances, such as non-hypertrophic scars, non-ablative fractional lasers may be preferred over ablative to decrease the risk of PIH.





Fig. 7. Before and 6 weeks after a single fractional ablative CO2 laser treatment for a scar. Note the improved texture, color, and thickness in certain areas. (Courtesy of Dr. Omar Ibrahimi.)

 

[madman]

CLINICAL CARE POINTS

*Acne is the most common dermatologic complaint and a complete cure remains elusive.

*Sebaceous glands are lipid-rich and the development of a lipid-selective 1726 nm wavelength offers the ability to selectively damage sebaceous glands.





Fig. 8. Before and 24 months after a series of 4 monthly treatments with a 1726-nm device. (Courtesy of Dr. EmilTanghetti & Accure Acne, Inc.)

 

[sammmy]

Waste of money in the majority of cases. They have a few success cases that are presented as the actual success rate, stimulating people to pay for unsuccessful procedures.

The hair reducing lasers have to be done every few months, the results are not permanent. The acne or blood vessel lasers are ineffective more often than not since they are not addressing the internal cause of these conditions.