Treatment of nevus of Ota with 1064 nm picosecond Nd:YAG laser: A retrospective study

Picosecond alexandrite laser treatment of nevus of Ota in children

BACKGROUND

The picosecond alexandrite laser has been safely and effectively used to treat the nevus of Ota in adults. However, limited data are available for children.

OBJECTIVE

To investigate the efficacy, safety, and correlative influencing factors of a 755nm picosecond alexandrite laser in the treatment of nevus of Ota in children.

METHODS

We retrospectively analyzed Chinese children with nevus of Ota who received a 755nm picosecond alexandrite laser treatment in a tertiary dermatological hospital.

RESULT

A total of 305 pediatric patients received an average of two treatments achieving an average of 79% pigment clearance. After the first treatment, 22 patients achieved complete clearance (95%-100%), and 72 patients achieved excellent response (75%-94%), with an average initial efficacy of 63% lesion clearance. Treatment at an early age achieved better initial efficacy (0- to 12-month group >1- to 6-year group, 6- to 12-year group). And 0- to 12-month group achieved better final efficacy. More treatment sessions also increased the final efficacy. Both initial efficacy and final efficacy were better when treating a darker lesion. The incidence of complications was 12.1%, with 10.8% being post-inflammatory hyperpigmentation and 1.3% being hypopigmentation. The rate of recurrence was 6.6%.

LIMITATION

Retrospective study.

CONCLUSION

A 755nm picosecond alexandrite laser is safe and effective in treating nevus of Ota in children. Younger to initiate treatment, darker lesions, and more treatments are positively associated with better pigmentation clearance.

Wavelength-dependent threshold fluences for melanosome disruption to evaluate the treatment of pigmented lesions with 532-, 730-, 755-, 785-, and 1064-nm picosecond lasers

BACKGROUND AND OBJECTIVES

A threshold fluence for melanosome disruption has the potential to provide a robust numerical indicator for establishing clinical endpoints for pigmented lesion treatment using a picosecond laser. Although the thresholds for a 755-nm picosecond laser were previously reported, the wavelength dependence has not been investigated. In this study, wavelength-dependent threshold fluences for melanosome disruption were determined. Using a mathematical model based on the thresholds, irradiation parameters for 532-, 730-, 755-, 785-, and 1064-nm picosecond laser treatments were evaluated quantitatively.

STUDY DESIGN/MATERIALS AND METHODS

A suspension of melanosomes extracted from porcine eyes was irradiated using picosecond lasers with varying fluence. The mean particle size of the irradiated melanosomes was measured by dynamic light scattering, and their disruption was observed by scanning electron microscopy to determine the disruption thresholds. A mathematical model was developed, combined with the threshold obtained and Monte Carlo light transport to calculate irradiation parameters required to disrupt melanosomes within the skin tissue.

RESULTS

The threshold fluences were determined to be 0.95, 2.25, 2.75, and 6.50 J/cm² for 532-, 730-, 785-, and 1064-nm picosecond lasers, respectively. The numerical results quantitatively revealed the relationship between irradiation wavelength, incident fluence, and spot size required to disrupt melanosomes distributed at different depths in the skin tissue. The calculated irradiation parameters were consistent with clinical parameters that showed high efficacy with a low incidence of complications.

CONCLUSION

The wavelength-dependent thresholds for melanosome disruption were determined. The results of the evaluation of irradiation parameters from the threshold-based analysis provided numerical indicators for setting the clinical endpoints for 532-, 730-, 755-, 785-, and 1064-nm picosecond lasers.

Interventional and device treatment of the periocular area

Growth in the research, innovation, and development of laser and energy-based technologies over the past few decades has led to dramatic increases in treatment options for dermatologic and cosmetic concerns of the periorbital area. We highlight recent treatment options using laser and energy-based devices for the clearance of periocular pigmented lesions, including solar lentigines and nevus of Ota; vascular lesions, including port-wine birthmarks, infantile hemangiomas, superficial telangiectasias, and reticular veins; laser ablation of benign tumors, such as xanthelasma; cosmetic rejuvenation; treatment of infraorbital dark circles and festoons; laser removal of eyebrow and eyeliner tattoos; and device-based treatment of chronic dry eyes.

Picosecond lasers in cosmetic dermatology: where are we now? An overview of types and indications

Q-switched lasers have undeniably revolutionized the field of laser dermatology since four decades ago. Just as the first-generation laser emits its photonic signal in a few nanoseconds, the picosecond laser delivers pulse widths of at least ten times shorter. These devices offer a powerful tool for treating a wide range of skin conditions with a minimal downtime for visible improvement. For the current study, a literature research was performed on the dermatological applications of picosecond laser. The literature searched on this topic between 1999 and 2023 accessible through various platforms produce a result of 62 articles. The included studies have discussed the application of picosecond laser technology in tattoo removal, treatment of epidermal and dermal pigmentation, and collagen remodeling. After sifting the data from the articles into tables, the results were discussed in detail. The study shows a lot of evidence towards the efficacy of picosecond laser, yet it draws attention to its downsides.

Update on lasers in pediatric dermatology: how primary care providers can help patients and families navigate appropriate treatment options and timelines

PURPOSE OF REVIEW

The use of lasers in pediatric dermatology is well established, but recent literature has expanded the evidence for specific timelines of treatment. Additionally, new devices and combinations with medical therapy have improved outcomes and treatment options for various conditions.

RECENT FINDINGS

Pulsed dye laser remains the first-line laser for vascular lesions. Recent guidelines support early initiation of laser treatment in port-wine birthmarks to optimize outcomes. For hemangiomas, laser treatment can offer a meaningful addition to oral propranolol therapy. Lasers with shorter wavelengths offer improved outcomes with decreased downtime for pigmented lesions. General anesthesia in the pediatric population continues to be a controversial topic, and the decision to perform laser under general versus topical anesthesia requires discussion with family of risks and benefits.

SUMMARY

Primary care providers can benefit their patients by prompt referral to dermatology for discussion of laser treatment. Port-wine birthmarks require referral in the first weeks of life so that laser treatment can be initiated if appropriate. Although many dermatologic conditions cannot be completely cleared or cured with laser, treatment can offer meaningful outcomes and benefit for patients and families.