The treatment of port-wine stains with the pulsed dye laser at 600 nm

The standard wavelength in the treatment of port-wine stains (PWS) with the pulsed dye laser is 585 nm. In many cases, the response to therapy is not adequate despite many treatments, depending partly on vessels out of reach of the laser. Longer wavelengths penetrate deeper into the dermis, but are absorbed less by oxyhaemoglobin, and require higher fluences. In this study, 22 patients with PWS were treated with the flashlamp-pumped pulsed dye laser using two different wavelengths, 585 and 600 nm. Four adjacent sites with PWS were treated on one occasion with 585 nm, 600 nm and equal fluence, and with 1.5 and 2 times the 585 nm fluence. The test areas were examined blindly, by four evaluators, an average of 12.5 weeks later. There was significantly less lightening with 600 nm than with 585 nm (P < or = 0.001) when equal fluences were used. When 1.5 and 2 times the 585 nm fluence were applied, with 600 nm the lightening was equal to that after 585 nm. However, in individual cases (11 of 22) 600 nm showed a superior lightening of at least 20% compared to 585 nm. There was slight hyperpigmentation and hypopigmentation, but no atrophy or scarring. In conclusion, 585 nm remains the wavelength of choice in treatment of PWS with the pulsed dye laser. However, in cases that do not respond satisfactorily with 585 nm, it may be worth trying 600 nm with a fluence that is at least 1.5-2 times the 585 nm fluence.

Evaluation of agreement among dermatologists in the assessment of the color of port wine stains and their clearance after treatment with the flashlamp-pumped dye laser

BACKGROUND

Color classification and its subjective clearance evaluation in response to treatment are essential in the management of patients with port wine stains (PWS). But color perception by physicians is not an objective measurement so that it can change among observers. Agreement among physicians is essential for the reliability of the color classification and the clinical assessment of the response to laser treatment.

OBJECTIVE

The purpose of our study was to determine the reliability of the clinical color classification of port wine stains and of their color change or clearance in response to laser treatment. The study was not designed to evaluate the outcome of laser treatment in PWS or the factors that could predict the final response.

METHODS

We used the kappa index to evaluate the proportion of agreement in color and clearance perception among dermatologists. Six dermatologists classified the initial color of PWS in 80 patients. Three of them also assessed the amount of clearance achieved after treatment with the flashlamp-pumped dye laser. These three dermatologists were usually dedicated to treat patients with PWS, while the other three were not.

RESULTS

The kappa index showed a substantial agreement in both cases. No difference in the initial color perception was observed between the group of dermatologists specialized in PWS and the other three dermatologists.

CONCLUSION

These results favor the reliability of the clinical method in the assessment of PWS before and after laser treatment. So, although subjective, color perception by physicians can be used in the study of laser treatment outcome in PWS and its related factors, and the results of different authors can be compared.

Port wine stains: laser treatment and nursing management

In 1960, an American physicist Theodore Maiman observed the first laser in action. Since then laser technology has progressed at an extraordinary rate. This article shows how one type of laser has touched the lives of thousands of people. The Candela tunable dye laser has given hope to people with port wine stain birthmarks. It also shows the duties and responsibilities of the nurse working with lasers and the possibility of the extended role of the nurse in the field of skin laser therapy.

Possible mechanisms for an irregular vessel coagulation when long laser pulses are used in the treatment of port-wine stains

The laser treatment of port-wine stains (PWS) has as a main aim the irreversible damage of ectatic vessels. Blood content of the subcutaneous venous plexus in PWS can be increased by a factor of seven or more, compared to that of the normal skin. The venous blood velocity ranges from 0.1-1 mm/s in capillaries to approximately 22 mm/s in larger vessels of about 300 microns in diameter. A PWS, selected for study, was irradiated with a multiline argon laser 488/515 nm wavelength, 1.5 W power, 200 ms pulse duration, 0.5 mm beam diameter and repetition frequency up to 5 Hz. Laser shots were placed adjacently in an area of 1 cm2. Using these parameters, in the case of dilated PWS vessels with an optical penetration depth and thermal diffusion length less than the diameter of the vessel, together with a transit time of blood across the irradiated spot less than the pulse duration, and estimating that during a pulsed laser emission of 200 ms, the blood has travelled a distance of 3-4 mm, there is a strong indication that hemodynamics during irradiation may influence the pattern of coagulation and agglutination. Thrombosis should occur in the case of small vessels and, in larger vessels, the coagulated blood will only partly fill the lumen. The structure developed in the vessel interior may also change continuously with time, as the coagulated material is progressively replaced by fibrotic tissue and the irregular agglutination pattern may be due to inhomogeneity in the absorbed optical energy.

Cutaneous lasers: a review

Lasers are versatile instruments capable of treating an ever-increasing array of cutaneous conditions. Various vascular, pigmented, epidermal, and dermal lesions can be selectively destroyed without damaging normal uninvolved skin structures by utilizing lasers that correspond to the absorption characteristics of the intended target. Recently, lasers have been used with much success in the treatment of rhytides, photodamaged skin, and scarring. The rapid development of laser technology has made many lasers obsolete that only a few years ago were considered state of the art. Lasers are more reliable, emit light at higher energies with shorter pulse widths, and at faster delivery rates. As is typically the case with high-technology devices, lasers are becoming less expensive and more consolidated. For this reason, laser techniques will continue to evolve and new indications for their use will, no doubt, be discovered in the near feature. Physicians treating the skin are in a unique position to study the clinical and histological effects of lasers, as the skin remains an easy-access organ. Laser medicine and surgery will continue to be enhanced by the contributions made through the investigative efforts of laser surgeons treating the skin.

Treatment response of port-wine stains with the flashlamp-pulsed dye laser in the National Skin Centre: a report of 36 patients

This is a report of a prospective study on the treatment response of 36 patients with port-wine stains with the 585 nm flashlamp-pulsed dye laser and who have completed at least 1 year of follow-up. All patients received treatment at 8-weekly intervals under topical lidocaine-prilocaine anaesthesia. Most of the patients received at least 4 treatments in total. At the end of each treatment and on completion of treatment, patients were assessed for response based on a subjective scoring system where excellent is more than 75% improvement (lightening of redness), good is 50% to 75% improvement, fair is 25% to 75% improvement and poor is less than 25% improvement and the same is no observable improvement. The author and patients administered the scores after each treatment separately. The mean age was 26.1 years (range 2 years to 53 years). The mean initial energy density dose was 6.432 J/cm2. Most patients experienced significant improvement after the initial treatment and further improvements were observed with each subsequent treatment. The author generally recorded better improvement scores than the patients. Ninety percent of the patients were satisfied with the outcome of treatment. Only 11% of the patients scored the improvement after treatment as excellent, while the author scored 36% of the lesions treated as excellent improvement. More than two-thirds of the patients observed good to excellent improvements after the first treatment and by the fourth treatment, all patients recorded either good or excellent improvement. There were no statistically significant differences in treatment response in the various types (papular or macular) of lesions and skin colour type of patients. Light coloured port-wine stains tended to respond better to treatment than darker lesions (not statistically significant), but overall, all coloured lesions responded well to treatment. Patients' expectations of improvement were generally higher than those of the author.

Evaluation of port wine stains by laser Doppler perfusion imaging and reflectance photometry before and after pulsed dye laser treatment

Treatment of choice for congenital capillary malformations of the port wine stain type is presently the pulsed dye laser. Although treatment results have usually been excellent or good, a few patients respond less well. Looking for a tool to predict and monitor the treatment we used laser Doppler perfusion imaging and reflectance photometry. Measurements with laser Doppler perfusion imaging were performed in 19 patients initially and after 1-3 treatments and with reflectance photometry initially and after 1-6 treatments. Before treatment, 15 of the patients had an increased bloodflow within the port wine stain in comparison with normal contralateral skin. After the laser treatments, 15 of 18 patients had decreased bloodflow within the lesion and all 18 had surrounding hyperemia. Reflectance photometry showed a successive increase in blanching and predicted within 6 weeks of the first treatment the eventual clinical result. The bloodflow, as measured with laser Doppler perfusion imaging, did not correlate well with the photometrically registered erythema. Reflectance photometry is a useful objective tool, which early in the treatment course indicates whether laser therapy will be successful. Laser Doppler perfusion imaging is less helpful in monitoring patients but may be of use in the study of port wine stain pathophysiology.