Copper vapour laser treatment of port-wine stains in brown skin

Numerical Modeling of The Dysplastic Vessel Heating in PWS by Yellow 578 nm Copper Vapor Laser Radiation for Different Skin Phototypes

Introduction: Many clinical studies and protocols have been written about laser treatment for fair skin phototypes. However, for dark-skinned phototypes, information is limited, and the risk of burns is higher, especially if the same settings are recommended for fair skin. Competitive epidermal melanin absorption decreases the light energy reaching dysplastic vessels in a port-wine stain (PWS), preventing the vessel from achieving the temperature of the desired clinical result. Therefore, the choice of safe laser settings for different skin phototypes can be realized using numerical modeling of PWS vessel heating. This study aimed to demonstrate the algorithm for choosing both effective and safe photodestruction of dilated dermal vessels in PWS with the copper vapor laser (CVL) at 578 nm for different skin phototypes. Methods: We used the multilayered skin model with different melanin content for detecting the safe laser parameters for PWS treatment. The calculation of the selective heating of the vascular component with CVL radiation at yellow 578-nm wavelengths for different skin phototypes was performed via Matlab mathematical programming system and its application Femlab for solving partial differential equations using the Finite element method. Results: We determined the location, depth, and size of blood vessels that could be selectively heated to coagulation temperature for different skin prototypes. CVL fluence values need to be reduced almost two times for skin phototype IV than for skin phototype II to provide safe CVL treatment. The maximum depth of the location of the vessels, which can be selectively heated to coagulation temperature, also decreased for dark skin phototypes. Histological and histochemical findings validated the results of our calculations. Conclusion: To our knowledge, the use of numerical simulation to optimize has not yet been considered. According to our calculations, CVL could selectively heat the dilated vessel, which occurred in purple and proliferative-type PWS for dark skin at the reduced fluence range and depth.

Port wine stain treatment outcomes have not improved over the past three decades

BACKGROUND

Since the early '80s, the pulsed dye laser has been the standard treatment tool for non-invasive port wine stain (PWS) removal. In the last three decades, a considerable amount of research has been conducted to improve clinical outcomes, given that a fraction of PWS patients proved recalcitrant to laser treatment. Whether this research actually led to increased therapeutic efficacy has not been systematically investigated.

OBJECTIVE

To analyse therapeutic efficacy in PWS patients globally from 1986 to date.

METHODS

PubMed was searched for all available PWS trials. Studies with a quartile percentage improvement scale were included, analysed and plotted chronologically. Treatment and patient characteristics were extracted. A mean clearance per study was calculated and plotted. A 5-study simple moving average was co-plotted to portray the trend in mean clearance over time. The data were separately analysed for multiple treatment sessions in previously untreated patients.

RESULTS

Sixty-five studies were included (24.3% of eligible studies) comprising 6207 PWS patients. Of all patients, 21% achieved 75-100% clearance. Although a few studies reported remarkably good outcomes in a subset of carefully selected patients, there was no upward trend over time in mean clearance.

CONCLUSION

The efficacy of PWS therapy has not improved in the past decades, despite numerous technical innovations and pharmacological interventions. With an unwavering patient demand for better outcomes, the need for development and implementation of novel therapeutic strategies to clear all PWS is as valid today as it was 30 years ago.

Laser surgery in dark skin

Although challenging, effective laser surgery in patients with darker skin tones can be achieved despite a higher inherent risk of side effects. Although the incidence of undesirable postoperative sequelae has decreased with the development of advanced laser technology and individualized treatment parameters, these risks may never be eliminated completely. Consequently, thorough patient preoperative preparation and education regarding the risks of cutaneous laser therapy will remain an essential component of treatment in darkly pigmented patients. In the future, as more refined laser techniques evolve, the ability to safely and effectively treat these patients will improve.

Laser surgery in dark skin

Although challenging, effective laser surgery in patients with darker skin tones can be achieved despite a higher inherent risk of untoward side effects. While the incidence of undesirable postoperative sequelae has decreased with the development of advanced laser technology and individualized treatment parameters, these risks may never be eliminated completely. Consequently, thorough patient preoperative preparation and education regarding the risks of cutaneous laser therapy will remain an essential component of treatment in darkly pigmented patients. In the future, as more refined laser techniques evolve, the ability to safely and effectively treat these patients will improve.