A retrospective analysis on the management of pigmented lesions using a picosecond 755-nm alexandrite laser in Asians

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.

Comparison of the fractionated Nd: YAG 1064-nm picosecond laser with holographic optics and the fractional CO2 laser in atrophic acne scar treatment: a prospective, randomized, split-face study

KEY POINT

The 1064-nm picosecond laser with holographic optics demonstrated significant efficacy in treating atrophic acne scars.

BACKGROUND

Picosecond lasers with fractionated optics have enabled the development of a breakthrough skin rejuvenation method. The authors compared the fractionated, non-ablative neodymium-doped yttrium aluminum garnet 1064-nm picosecond laser with holographic optics and the fractional CO2 laser in treating atrophic acne scars.

METHODS

One side of each patient's face was randomly allocated and treated with three sessions of the 1064-nm picosecond laser with holographic optics at 2-month intervals. In contrast, the other side was treated with the fractional CO2 laser. Participants were followed up 3 months after the final session. The primary outcome included the physicians' evaluation using the ECCA grading scale and a four-point scale to assess improvement. The patients' assessment of progress, their overall satisfaction and preferences, and the side effects were also evaluated.

RESULTS

No significant difference was observed between the two lasers in terms of the mean ECCA scores after treatments (P = 0.209). The physicians' improvement assessment was more significant for the fractional CO2 laser (P = 0.001). The patients' evaluation of improvement and subjective satisfaction were consistent with physicians' four-point scale results. The picosecond laser side had fewer adverse effects (P < 0.001).

CONCLUSION

The fractionated, non-ablative Nd: YAG 1064-nm picosecond laser with holographic optics and the fractional CO2 laser were effective and safe in treating atrophic acne scars. Significantly better clinical outcomes were observed with the fractional CO2 laser, whereas fewer adverse effects were noted with the 1064-nm picosecond laser with holographic optics.

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.

Evaluation of the Efficacy of the 755 nm Picosecond Laser in Eliminating Pigmented Skin Lesions after a Single Treatment Based on Photographic Analysis with Polarised Light

INTRODUCTION

Pigmentary changes can be bothersome and affect one's well-being. Laser therapy has been shown to effectively treat such skin discolouration. We aimed to assess the utility of a 755 nm alexandrite laser in pigmented lesions removal.

MATERIALS AND METHODS

A total of 109 patients aged 44.17 ± 8.2 years were enrolled and underwent laser treatment of facial skin hyperpigmentation. The efficacy was analysed on the basis of photographic diagnosis using the VISIA Complexion Analysis System. The following measures were assessed: (1) score; (2) feature count; (3) comparison figure.

RESULTS

A single laser treatment significantly improved the size and area of the lesion and decreased the number of lesion features. Parallelly, the overall skin condition significantly improved (p < 0.05). We found a statistical tendency of a higher feature count baseline, thus its change in men (p = 0.05 and 0.07, respectively), but failed to find any statistically significant associations (p > 0.05) between tested measures and skin phototypes and hyperpigmentation types. Age was also not correlated with the laser efficacy (p > 0.05).

CONCLUSIONS

The use of the 755 nm laser is effective in reducing pigmented lesions.

Updates on Lasers in Dermatology

The introduction of selective photothermolysis by Drs. John Parrish and Rox Anderson in 1983 revolutionized how lasers are used in dermatology. The theory allowed for lasers to be used in a variety of applications both safe and effectively, and the number of applications has only expanded with time. From the first application on vascular birthmarks to more recent applications for acne, this review covers the evolution of lasers from the beginning to where we are headed.

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.

Treatment of Periorbital Vascularity, Erythema, and Hyperpigmentation

Periorbital hyperpigmentation (POH) is a common aesthetic concern that impacts patients' emotional well-being and quality of life. POH can be difficult to manage as the etiology is often multifactorial or difficult to elucidate. An understanding of different contributing factors and ability to classify hyperpigmentation can aid in the management of POH. Classification of POH is divided into pigmented, vascular, structural, and mixed subtypes. A wide array of treatment options has been proposed belying the challenges inherent to improving POH. Modalities vary from topical therapies, chemical peels, dermal fillers, and lasers, to surgical intervention. Because POH can be multifactorial, successful management of POH will depend on elucidating the etiology and often requires a combination of therapies.

Prospective comparison study of a 550 picosecond 755 nm laser vs a 50 ns 755 nm laser in the treatment of nevus of Ota

Since the introduction of selective photothermolysis, Q-switched nanosecond lasers have been used for the treatment of dermal pigmented lesions. Over the past several years, picosecond lasers have been introduced to the cosmetic community. We recently performed a study comparing a 550 picosecond 755 nm laser versus a 50 ns 755 nm laser, with the purpose of evaluating the clinical efficacy and complications of each laser when treating nevus of Ota. Ten Asian patients with nevus of Ota were enrolled in the study. Each lesion was split into 2 parts, and patients were treated with a 755 nm picosecond laser (PSL) and a 755 nm nanosecond laser (NSL). The clinical endpoint for fluence choice was immediate whitening (PSL: 2.33 ~ 3.36 J/cm2, NSL: 5.5 ~ 7 J/cm2) of the treated area. The pulse duration was fixed at 550 picoseconds (PSL) and 50 ns (NSL). The spot size of each laser was 2.5-3 mm. Laser treatments were performed until excellent clinical improvement was observed. Patients were examined 1 week after the first treatment, at each follow-up visit, and 6 months after the last laser treatment. The average number of treatment sessions to achieve excellent clinical improvement was 4.2 treatments using PSL and 5.4 treatments using NSL. One case of hyperpigmentation and one case of hypopigmentation were observed in the NSL treatment group. There were no complications in the PSL treatment group. The 755 nm 550 picosecond laser is significantly more effective than the 755 nm 50 ns laser in the treatment of nevus of Ota. The PSL treatment group also had minimum side effects.

Combination 1550 nm non-ablative fractional resurfacing and laser hair removal for treatment of Becker's nevi in skin types III-VI

OBJECTIVES

Becker's nevus is a cosmetically bothersome benign hamartoma typically associated with basal layer hyperpigmentation and hypertrichosis. We herein present the largest case series characterizing treatment parameters and clinical outcomes of combined 1550 nm non-ablative fractional resurfacing and laser hair removal (long-pulsed neodymium-doped yttrium aluminum garnet or alexandrite) in the treatment of Becker's nevus. This is also the largest case series of laser treatment of Becker's nevus in Fitzpatrick skin types V and VI.

METHODS

We performed a retrospective review of patients treated between 2016 and 2021. Clinical photographs were graded by three independent physicians using a 5-point visual analog scale.

RESULTS

Twelve patients (mean age: 24.8 years, Fitzpatrick skin types III-VI) were treated for Becker's nevus on the face (4) or the trunk and/or extremities (8). Four patients were Fitzpatrick skin types V or VI. On average, patients received 5.3 treatments in 1-4-month intervals. Ten of the 12 patients had concomitant laser hair removal preceding same-day non-ablative fractional resurfacing (n = 7 with long-pulsed 1064 nm neodymium-doped yttrium aluminum garnet and n = 3 with long-pulsed 755 nm alexandrite). The number of treatments with each modality was determined by patient satisfaction with improvement in hyperpigmentation and hypertrichosis. At follow-up, which ranged from 6 to 40 weeks (mean 10.5 weeks), patients were given a mean improvement score of 51%-75%. No long-term adverse events were encountered in either group. Limitations include a small sample size and a lack of long-term follow-up.

CONCLUSION

Combination 1550 nm non-ablative fractional resurfacing and laser hair removal is safe and efficacious in the cosmetic reduction of hyperpigmentation and hypertrichosis associated with Becker's nevus, including those with Fitzpatrick skin types V and VI.

The Efficacy and Safety of a 755-nm Picosecond Laser in the Treatment of Physiologic Lip Hyperpigmentation in Thai Patients

BACKGROUND

Physiologic lip hyperpigmentation is a common aesthetic concern, especially in Southeast Asia. There is limited data on the application of the picosecond laser for this condition.

OBJECTIVE

To evaluate the efficacy and safety of using a 755-nm picosecond laser in the treatment of physiologic lip hyperpigmentation.

METHODS

Twenty healthy patients with physiologic lip hyperpigmentation received 5 bi-weekly treatments with a 755-nm picosecond laser using a 6-mm spot size, fluence of 0.71 J/cm 2 at 5 Hz. Subjective and objective evaluation on the improvement of lip hyperpigmentation were obtained at baseline, 2 weeks after each treatment and at 1, 3, and 6 months after the final treatment. Patient self-assessment, pain score, and adverse reactions were also recorded.

RESULTS

All patients completed the study and attended all follow-ups. Most (52.6%) patients presented with moderate clinical improvement at 6-month follow-up. The average melanin index decreased significantly after the fourth treatment ( p = .048) and at 1-month follow-up ( p = .026). More than half the patients (70%) reported moderate-to-marked improvement at 6-month follow-up. Only 1 patient presented with a transient adverse reaction of lip edema.

CONCLUSION

The 755-nm picosecond laser is safe and effective for the treatment of physiologic lip hyperpigmentation in Thai patients.

Laser treatment of benign melanocytic lesion: a review

Treatment of pigmented lesions is one of the major challenges of laser and cosmetic practitioners. The most common pigmented lesions that are treated by lasers are melanocytic nevi, ephelides, solar lentigines, and café au lait macules. Melanin absorbs different wavelengths (500-1100 nm); thereby, treatment of various pigmented lesions requires the application of lasers with different wavelengths. Choosing the most appropriate type of laser depends on various factors such as the chromophore and the location of a specific lesion in the skin. In this paper, we aim to review the most efficient laser treatment protocols for each pigmented skin lesion and compare their efficacy in each part based on the previous studies.

An update on Becker's nevus: pathogenesis and treatment

Becker's nevus (BN) manifests as a hyperpigmented, sometimes hypertrichotic plaque/patch over the chest and shoulder, and it is in the category of benign cutaneous hamartomas. BN has elongation and fusion of the rete ridge, keratotic plugging, sebaceous hyperplasia, smooth muscle hyperplasia, and hyperpigmentation of the basal/suprabasal layer histologically. This article highlights all issues involved in pathogenesis and treatment options of BN. According to current research, postzygotic ACTB mutations induce BN and Becker's nevus syndrome (BNS). Although several therapy strategies were utilized to treat the pigmentary and hypertrichotic aspects of BN, no definitive standard treatment was identified to far, and further research is needed to better educate BN care. This article is protected by copyright. All rights reserved.

A Randomized, Evaluator-blinded Comparative Study of a Potassium Titanyl Phosphate (KTP) 532-nm Picosecond Laser and an Alexandrite 755-nm Picosecond Laser for the Treatment of Solar Lentigines in Asians

BACKGROUND

Various pigment-specific lasers can be used to treat solar lentigines. However, the most effective treatment options remain to be explored to reduce complications, such as post-inflammatory hyperpigmentation, especially in dark-skinned patients.

OBJECTIVES

This study aims to compare the efficacy and safety between the KTP 532-nm picosecond laser and the alexandrite 755-nm picosecond laser for the treatment of solar lentigines in Asians.

MATERIALS AND METHODS

Thirty patients who had at least two solar lentigines on their arms were enrolled. A total of 30 paired lentiginous lesions were randomly selected for a single treatment with either a KTP 532-nm picosecond laser or an alexandrite 755-nm picosecond laser. Mean luminance score (L*) was evaluated at baseline and at six, and 12 weeks to determine treatment efficacy. Improvement was assessed by a blinded physician using a 5-point score. Satisfaction was rated by patients using a visual analogue scale. All adverse events were documented.

RESULTS

All 30 patients completed the study. Both lasers showed significant improvement in mean L* from baseline (p<0.001). With the parameter settings employed, lesions treated with the alexandrite 755-nm picosecond laser showed greater improvement in mean L* when compared with treatment with the KTP 532-nm picosecond laser at 12 weeks follow-up (p=0.002). According to physician scoring, more than 50% improvement was observed in 25 and 19 lesions of the alexandrite 755-nm picosecond laser group and the KTP 532-nm picosecond laser group, respectively. Adverse events did not differ between groups. A significantly higher satisfaction score was observed with the alexandrite 755-nm picosecond laser at the last visit (p=0.038).

CONCLUSION

Both types of picosecond laser may be used to treat solar lentigines. Proper treatment settings and endpoint observation are the most important factor to achieve a successful outcome.

Early Treatment Initiation Improves Outcomes in Nevus of Ota: A 10-Year Retrospective Study

BACKGROUND

Nevus of Ota is a psychologically burdensome facial pigmentation birthmark common in Asian populations. Laser therapy is currently the first-line treatment, but no guidelines on when to initiate treatment have yet been established.

OBJECTIVES

Our objective was to determine the correlation between treatment efficacy and safety, risk of recurrence, and age of treatment initiation in patients receiving laser therapy for nevus of Ota.

METHODS

We conducted a 10-year (2008-2018) retrospective cohort study of all patients who completed a minimum of five laser treatments at Siriraj Skin Laser Center, Mahidol University, Bangkok, Thailand.

RESULTS

A total of 84 patients (aged 4 months-50 years) with nevus of Ota lesions were enrolled in the study. All patients were treated with a 1064-nm Q-switched Nd:YAG or a 755-nm or 1064-nm picosecond-domain laser (or a combination thereof). Our analysis identified that initiation of laser therapy before the age of 5 years was a significant factor in reducing the number of sessions necessary to achieve aesthetic improvement (P < 0.01; 95% confidence interval [CI] 1.06-3.21). In total, 18 patients (21.4%) initiating treatment before the age of 5 years required an average of 2, 4, and 7 treatment sessions to achieve > 25, 50, and 75% of pigment lightening, respectively, whereas 66 patients (78.6%) initiating treatment after the age of 5 years required an average of 3, 7, and 11 sessions to achieve comparable clearance. The risk of postinflammatory hyperpigmentation was significantly lower in patients starting treatment before the age of 5 years (P < 0.01; 95% CI - 43.76 to - 11.94). Recurrences were not observed in patients achieving > 95% clearance.

CONCLUSIONS

In our patient cohort, initiation of laser treatment for nevus of Ota before the age of 5 years significantly improved therapeutic outcomes and reduced the risk of adverse events and recurrence.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov PRS number: NCT04481178.

Efficacy and safety of picosecond 755-nm alexandrite laser for treatment of nevus of Ota in Taiwanese children: A retrospective study

OBJECTIVES

To evaluate the efficacy and safety of picosecond 755-nm alexandrite laser in the treatment of nevus of Ota in children.

MATERIALS AND METHODS

A retrospective study was conducted by reviewing medical charts and photographs of 86 Taiwanese children with various types of nevus of Ota between January 2017 and September 2020. Picosecond 755-nm alexandrite laser therapy was used to treat pigmentary lesions. Percent clearance of lesions during treatment and the treatment time required to achieve 95%-100% clearance were determined.

RESULTS

According to Tanino's classification or Peking University Medical College Hospital (PUMCH) classification of nevus of Ota, most patients belonged to Tanino's Type II (32%) and Type III (38%) or PUMCH Type IIb (33%) and Type IIIb (26%), which indicated that the nevus was mainly distributed in the forehead, upper and lower eyelid, zygomatic, cheek, and temple regions. After treatment with picosecond 755-nm alexandrite laser, 96.5% of the patients achieved 95%-100% clearance with an average of 4.3 treatment sessions. The earlier onset of lesions (before 5 months of age) and the darker Fitzpatrick skin types (type IV vs. type III) significantly increased the number of treatments required to achieve clear response, while sex, age at first treatment, Tanino's classification of nevus, and color of nevus had no significant effect. Posttreatment hypopigmentation or hyperpigmentation was transient and resolved within 6 months. No serious response of the skin was evident.

CONCLUSION

Picosecond 755-nm alexandrite laser treatment of nevus of Ota in children was safe and effective. The treatment was well-tolerated, and only a few transient, minor side effects occurred.

A single-blinded, randomized, controlled trial comparing efficacy between low-fluence alexandrite 755-nm picosecond laser and low-fluence neodymium-doped yttrium aluminum garnet (Nd:YAG) 1064-nm picosecond laser for the treatment of ultraviolet B-induced hyperpigmentation

BACKGROUND

Hyperpigmentation is a common concern of patients in dermatology clinics. Although there are many treatment options, lasers are considered a promising therapy for various hyperpigmentary conditions.

OBJECTIVES

This study aims to evaluate the efficacy of alexandrite 755-nm picosecond and neodymium-doped yttrium aluminum garnet (Nd:YAG) 1064-nm picosecond lasers for the treatment of ultraviolet B (UVB)-induced hyperpigmentation in Asians.

MATERIALS AND METHODS

A randomized, single-blinded study was conducted. UVB-induced hyperpigmentation was performed in three spots by narrowband UVB. After 2 weeks, these three spots were allocated into 755-treated, 1064-treated, and control sites. Patients received weekly laser treatments for five sessions. Follow-ups were scheduled at 1 and 2 months after the last session.

RESULTS

Twenty patients attended the study. Overall, 755-nm and 1064-nm picosecond lasers showed a significant improvement in the mean lightness index (L*) compared to the control site, which started at Day 49 and Day 77, respectively. The mean L* of the 755-nm-treated site was also higher than that of the 1064-nm-treated site at Day 105 (p ≤ 0.001). Initially, the mean L*, physician's visual analog scale (VAS), and patient satisfaction with the 1064-nm picosecond laser were better than those with the 755-nm picosecond laser. Nevertheless, an inversion of the mean L* and VAS was noted at Day 49, whereas the mean patient satisfaction was noted at Day 77. In the subgroup analysis, a 755-nm picosecond laser effectively treated Fitzpatrick skin types (FPTs) III and IV. However, the mean L* of the 1064-nm picosecond laser was not significantly different from that of the control for FPT4.

CONCLUSION

The alexandrite 755-nm picosecond and Nd:YAG 1064-nm picosecond lasers appear to be effective and safe modalities for treating UVB-induced hyperpigmentation. With the setting employed in this study, the outcome after the 755-nm picosecond laser treatment seemed superior to that of the 1064-nm picosecond laser treatment, especially for FPT4.

Laser-Assisted Drug Delivery of Tranexamic Acid by Picosecond Laser in Postinflammatory Hyperpigmentation: A Split-Area Double Blind Randomized Prospective Study

Background: Tranexamic acid has been reported to benefit the treatment of postinflammatory hyperpigmentation (PIH). Laser-assisted drug delivery (LADD) could facilitate the efficacy of topically applied drugs into the dermis. This split-area randomized prospective study aims to assess whether early utilization of the LADD procedure with tranexamic acid delivery followed by picosecond lasers can attenuate the PIH better than the utilization of picosecond lasers alone. Patients and methods: Ten post-traumatic cases of PIH in 10 patients (8 female and 2 male) with an average age of 34.2 ± 11.2 years were included in this clinical trial. Using block randomization to determine the treatment side, one side of each area of the PIH was separated from the midline into two halves belonging to the control and tranexamic acid groups. The half area of the tranexamic acid group was further topically applied with 10% tranexamic acid solution. This procedure was repeated every 6 weeks, four times in total. Results: The self-assessment of the hyperpigmentation and overall satisfaction of the treatment outcome were not significantly different between the treatment and control sides. Conclusions: This split-area study revealed that, compared with picosecond alone, there was no significant difference adopting tranexamic acid in LADD after nonablative fractional picosecond laser for PIH.

Treatment of facial and non-facial lentigines with a 730 nm picosecond titanium: Sapphire laser is safe and effective

Objective

A 730 nm picosecond‐domain laser was developed to improve the clearance of pigmented lesion and reduce adverse events. This study assessed the safety and efficacy of this system for the clearance of lentigines and explores how the short picosecond pulses interact with tissue via histology.

Study Design and Methods

Twenty subjects with Fitzpatrick skin types II–IV were enrolled in this prospective, IRB‐approved study. Four treatments were administered using a 730 nm picosecond‐domain laser. Pre‐ and posttreatment photos were assessed by blinded reviewers at 4‐ and 12‐week follow‐up visits, using a 5‐point clearance scale. Subject satisfaction was measured using a 5‐point scale. Investigator Global Improvement Score (IGIS) was performed at the 4‐ and 12‐week follow‐up visits, using an 11‐point clearance scale. Subject pain level was measured using an 11‐point scale (no pain [0], extreme pain [10]). Histology of 730 and 532 nm picosecond pulses was compared with 755 and 532 nm nanosecond pulses.

Results

Sixteen subjects with a total of 118 discontinuous treatment areas, each comprised of 1–20 lesions, completed all study visits. Thirty body regions were studied, including arms (6), hands (16), scalp (1), forehead (2), face (3), and back (2). Spot sizes ranging from 2 to 5 mm diameters were used with fluences ranging from 0.8 to 4.0 J/cm². Mean pain score was 3.6 of 10 for all four treatments. Ninety‐nine percent of randomly paired 4‐week posttreatment images and 100% of 12‐week posttreatment images were correctly identified from their respective baseline images by three blinded reviewers. Mean IGIS demonstrated scores of 6.7 and 7.0 at 4‐ and 12‐week follow‐up visits, respectively. At the 4‐ and 12‐week follow‐up visits, 76% and 73% of subjects, respectively, were satisfied to highly satisfied. The mean clearance score for all 118 treatment areas was 3 of 4 in follow‐up visits. At 12‐week follow‐up, 36% of 118 treatment areas had a clearance score of 4, and 38% had a clearance score of 3. Post treatment, there was typical erythema, edema, dryness, crusting, and itching but negligible purpura, no pinpoint bleeding, blistering or scarring, and no significant hyperpigmentation or hypopigmentation. Histology showed diffuse, focal epidermal vacuolization ~5–10 µm in diameter and mild extravasation of erythrocytes with 730 nm picosecond pulses, while diffuse epidermal vacuolization was observed with coalescence of vacuoles (~20–100 µm), junctional clefting and mild extravasation of erythrocytes with 755 nm nanosecond pulses. Picosecond pulses of the wavelength of 532 nm produced diffuse, focal epidermal vacuolization and larger dermal vacuoles to depths of 500 µm, while 532 nm nanosecond pulses produced diffuse epidermal vacuolization with coalescence of vacuoles and marked dermal hemorrhage.

Conclusion

This study demonstrated the potential of a new 730 nm picosecond‐domain laser for the clearance of lentigines. The results showed good clearance with no adverse events and good subject satisfaction in patients with skin type II–III. Additional studies need to be conducted on darker skin types. The histopathologic findings demonstrate that the picosecond 730 nm laser produces excellent selectivity for pigment with minimal disruption of the dermal–epidermal junction and may therefore reduce healing times and the risk of adverse events.

Efficacy and Safety of Treatment with Fractional 1,064-nm Picosecond Laser with Diffractive Optic Element for Wrinkles and Acne Scars: A Clinical Study

Background

Fractional picosecond lasers is effective for the treatment of wrinkles or acne scars.

Objective

To investigate the safety and efficacy of treatment with a fractional 1,064-nm picosecond laser with a diffractive optic element for facial wrinkles and acne scars.

Methods

This prospective open-labeled trial comprised 22 subjects with facial wrinkles or acne scars. Subjects received three laser treatments with a fractional 1,064-nm picosecond laser at 3-week intervals. The efficacy and safety were evaluated at every visit and 2 months after the final treatment (14 weeks from the first treatment session). Global photographic assessments were performed by three blinded dermatologists and the subjects. Skin profilometry was performed using three-dimensional digital photographs; viscoelasticity was measured.

Results

The overall mean global improvement scores assessed by the dermatologists at weeks 3, 6, and 14, were 1.8±1.46, 2.5±1.88, and 3.5±1.84, respectively, and those assessed by the subjects were 2.7±2.08, 4.1±2.24, and 5.0±2.52, respectively. Skin profilometry showed significant improvements in the skin wrinkles, texture, depressions, and pores. The gross elasticity and skin firmness significantly improved by 10.96% and 9.04%, respectively. The major adverse reactions were erythema, pruritus, and petechiae, which disappeared within 2~3 days.

Conclusion

The fractional 1,064-nm picosecond laser is an effective and safe therapeutic modality for skin rejuvenation.

Efficacy and safety of 755 nm Q-switched Alexandrite Laser for Hori's nevus: a retrospective analysis of 482 Chinese women

To evaluate the efficacy and safety of 755 nm Q-Switched alexandrite laser for Hori's nevus in a large cohort of Chinese women. We retrospectively analyzed the efficacy and safety of 755 nm Q-Switched alexandrite laser for Hori's nevus. Reduction in pigment was evaluated using a 4-score method. A total of 482 patients, aged 16 to 52 years, were included in this analysis. Patients were treated with 755 nm Q-Switched alexandrite laser at fluence levels of 5-8 J/cm² for 2-4 treatment sessions. Following the treatments, 53% of patients showed over 75% reductions in pigment while 50-75% reductions in pigment were observed in 28% of patients. The rest displayed less than 50% improvements. Efficacy was positively correlated with the number of treatment sessions (p < 0.0001). Adverse reactions were temporary, mild erythema, and edema. A small portion of patients (15%) had hyperpigmentation, which disappeared within 2-6 months. 755 nm Q-Switched alexandrite laser is safe and has moderate benefits for Hori's nevus. Because its efficacy is positively correlated with the number of treatment sessions, increase in treatment sessions possibly could achieve a better outcome.

Novel Application of the 730 and 785 nm Picosecond Titanium Sapphire Lasers for the Treatment of Nevus of Ota

BACKGROUND AND OBJECTIVES

Nevus of Ota is a benign dermal melanocytosis that may pose significant psychosocial distress to patients. Q-switched nanosecond lasers have traditionally been considered the first-line treatment but pain, bleeding, and postinflammatory pigmentary alteration are common adverse effects. Picosecond devices have been increasingly used to treat nevus of Ota with promising results. We present two cases demonstrating novel applications of the 730 and 785 nm picosecond titanium sapphire lasers for the treatment of nevus of Ota in two patients with types III and IV skin.

STUDY DESIGN/MATERIALS AND METHODS

A 730 and 785 nm picosecond titanium sapphire laser with pulse durations of 250 and 300 picoseconds, respectively, were used to treat two cases of nevus of Ota. Four to seven treatment sessions were conducted at monthly intervals, and follow-up evaluation was performed 1-3 months following the final treatment session.

RESULTS

Both cases demonstrated greater than 75% clearance following treatment. There were no adverse events or pigmentary alteration noted as a result of picosecond titanium sapphire laser treatment.

CONCLUSIONS

The 730 and 785 nm picosecond titanium sapphire lasers are safe and effective for the treatment of nevus of Ota. Lasers Surg. Med. 00:00-00, 2021. © 2021 Wiley Periodicals LLC.

Incident Fluence Analysis for 755-nm Picosecond Laser Treatment of Pigmented Skin Lesions Based on Threshold Fluences for Melanosome Disruption

Background and Objectives

In this study, the threshold fluences for disrupting the melanosomes for pigmented skin lesion treatment were determined using a 755‐nm picosecond laser for clinical use. Based on the melanosome disruption thresholds, incident fluences corresponding to the target lesion depths were evaluated in silico for different laser spot sizes.

Study Design/Materials and Methods

Melanosome samples were isolated from porcine eyes as alternative samples for human cutaneous melanosomes. The isolated melanosomes were exposed to 755‐nm picosecond laser pulses to measure the mean particle sizes by dynamic light scattering and confirm their disruption by scanning electron microscopy. The threshold fluences were statistically determined from the relationships between the irradiated fluences and the mean particle sizes. Incident fluences of picosecond laser pulses for the disruption of melanosomes located at different depths in skin tissue were calculated through a light transport simulation using the obtained thresholds.

Results

The threshold fluences of 550‐ and 750‐picosecond laser pulses were determined to be 2.19 and 2.49 J/cm², respectively. The numerical simulation indicated that appropriate incident fluences of picosecond laser pulses differ depending on the depth distribution of the melanosomes in the skin tissue, and large spot sizes are desirable for disrupting the melanosomes more deeply located within the skin tissue.

Conclusion

The threshold fluences of picosecond laser pulses for melanosome disruption were determined. The incident fluence analysis based on the thresholds for melanosome disruption provides valuable information for the selection of irradiation endpoints for picosecond laser treatment of pigmented skin lesions. Lasers Surg. Med. © 2021 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC

Treatment of pigmentary disorders using picosecond laser in Asian patients: A meta-analysis and systematic review

There were many studies evaluating the effect of picosecond (PS) lasers, but no meta-analysis examined the effects of PS laser in the treatment of pigmentary disorders in Asians. The aim of this article was to review the before-after effect of PS laser in Asians for the treatment of pigmentary disorders. PubMed, Embase, and Cochrane library were searched for articles published up to May 2020. The evaluations were summarized into a 4-point scale that ranged from <25% (poor), 25%-50% (fair), 50%-75% (good), and 75%-100% (excellent). Effect sizes (ESs) were calculated according to laser wavelengths and lesion types. There were two randomized controlled trials, three single-arm trials, and three case series, with 200 patients. At 3 months after treatment, of all included patients, 3% (95%CI: 1%-6%) were evaluated as poor or worse, 9% (95%CI: 2%-21%) as fair, 29% (95%CI: 12%-50%) as good, and 56% (95%CI: 28%-83%) as excellent. The 532 and 1064, and 755 nm PS lasers had similar ESs across all four response groups. This meta-analysis suggested that 56% of Asian patients who underwent PS laser for the treatment of pigmentary disorders were evaluated as "excellent" about the pigment clearance by a dermatologist at least 3 months after treatment.

Clinical Evaluation of Safety and Efficacy of a 670-nm Picosecond Laser for Treatment of Benign Pigmented Lesions in Asians

BACKGROUND

Picosecond lasers are increasingly being investigated in treating pigmentation disorders because they may provide better treatment efficacy and comfort compared with nanosecond lasers.

OBJECTIVE

This study aims to evaluate the efficacy and side effect of a novel 670-nm picosecond laser in the removal of benign pigmented lesions (BPLs) in individuals with Fitzpatrick skin types (FST) III and IV.

MATERIALS AND METHODS

Fifteen subjects with solar lentigines and 7 subjects with ABNOMs received a single treatment with a 670-nm picosecond laser. Blinded physicians assessed the pigment clearance using a 5-category grading system scale. All subjects were evaluated at 1 month, 3 month, and 6 month after a single treatment. Adverse events were recorded at every follow-up visit.

RESULTS

All subjects with lentigines had complete clearance (95%-100%) of lesions during 3-month follow-up after a single treatment session of 670-nm picosecond laser, whereas 75% of the subjects with ABNOMs noted fair lightning (25%-49%) of lesions. Mild hypopigmentation and hyperpigmentation were observed in 9% and 14% of the subjects, respectively, which resolved within 3 months after the treatment.

CONCLUSION

The novel 670-nm picosecond laser is a safe and effective treatment for BPLs in subjects with FST III and IV with low rates of transient adverse effects.

Objective and Long-Term Evaluation of the Efficacy and Safety of a 1064-nm Picosecond Laser With Fractionated Microlens Array for the Treatment of Atrophic Acne Scar in Asians

BACKGROUND AND OBJECTIVE

Fractional 1064-nm picosecond-domain laser has recently been utilized for the treatment of atrophic acne scars and showed promising results. However, data on the safety and efficacy of this procedure in dark-skinned patients are limited. This prospective, self-controlled study was conducted to objectively evaluate the safety and efficacy of a 1064-nm picosecond laser coupled with a microlens array (MLA) for the treatment of atrophic acne scars on Asian skin.

STUDY DESIGN/MATERIALS AND METHODS

Twenty-six subjects of Fitzpatrick skin types (FSTs) III and IV with atrophic acne scars were enrolled. All subjects were treated with a 1064-nm picosecond laser (spot size of 8 mm, fluence of 1.0 J/cm² , a repetition rate of 10 Hz) in combination with the MLA handpiece for an average of three passes, for 6 monthly sessions. Objective (measurement of scar volume using three-dimensional (3D) photography and skin roughness analysis using ultraviolet A-light video camera) and subjective (clinical evaluation by two blinded dermatologists) assessments were obtained at baseline and at 1, 3, and 6 months after the final treatment.

RESULTS

Statistically significant reduction of the scar volume from baseline at 1, 3, and 6 months after the final treatment were observed by 3D photography and ultraviolet A-light video camera. At the 6-month follow-up, 50% (13 of 26) of the subjects were rated as having at least 50% improvement of the scars. The rate of improvement significantly increased from the 1-month follow-up to the 6-month follow-up (P = 0.013). Similarly, at the 6-month follow-up, the scar volume (P = 0.024) and skin roughness (P = 0.001) also significantly improved, in comparison with the baseline. Mild postinflammatory hyperpigmentation (PIH) was observed to develop in approximately 18% of all the treatment sessions. All cases of PIH were temporary and resolved within 4 weeks on average.

CONCLUSIONS

The 1064-nm picosecond laser with MLA is a safe therapeutic alternative for the treatment of atrophic acne scars in dark-skinned individuals. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Epiderm-Abrasion-Assisted Intensive Pulsed Light and Radiofrequency in Aesthetic Treatment Extensive Facial Freckles

BACKGROUND

Freckles are typical epidermal pigmented disorders that occur at sun-exposed areas, presenting with dark-brown or light-brown circular hyperpigmentation. A lot of treatment modalities have been used for treatment of freckles like chemicals, electrosurgery and cryotherapy. These treatments may cause undesirable side effects such as scaring (Sarkar et al. in Indian J Dermatol 62(6):578-584, 2017). Microdermabrasion has been used in treatment of freckles; however, the results are not satisfactory, as it removes the outermost layer of the epidermis only (El-Domyati et al. in J Cosmet Dermatol 15(4):503-513, 2016). Also ablative lasers and non-ablative lasers have been used but have not proved to be completely satisfactory and share a common risk of post-inflammatory hyperpigmentation (Jang et al. in Dermatol Surg 26:231-234, 2000). In our study, we have used epiderm-abrasion-assisted intensive pulsed light (IPL) and radiofrequency (RF) to study their effect in treatment of freckles.

PATIENTS AND METHODS

this prospective controlled clinical trial was carried out on 48 patients, who presented with extensive facial freckles, in the period between March 2015 and April 2018. The epiderm-abrasion procedure was performed first, and then, electro-photobiomodulation sessions were started two weeks later.

RESULTS

This study was carried out on 48 patients, 39 female and 9 males. Their age ranged between 12 and 58 years old. According to Fitzpatrick classification, four patients were type II, 30 patients were type III, and 14 patients were type IV. The results were excellent in 32 cases, good in 12 cases, fair in four cases, and we have no poor results. Side effects like hyperpigmentation were reported in three patients (6.3%), one case grade III and two cases grade IV Fitzpatrick skin type. No cases with hypopigmentation, or scars, were reported.

CONCLUSIONS

Epiderm-abrasion and electro-photobiomodulation (IPL&RF) are effective methods in treatment of facial freckles. Some complications may occur post-procedure such as hyperpigmentation, hypopigmentation and abnormal scarring.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

[Treatment of pigmentation disorders in association with systemic diseases]

Pigmentation disorders are a frequent skin problem and incorporate a broad spectrum of diseases, caused by an abnormal melanin pigmentation or also non-melanin pigmentation of the skin. Both hypermelanosis and hypomelanosis can be hereditary or acquired. This article summarizes the treatment approaches that are used in the majority of acquired pigmentation disorders of the skin. The following forms of hypermelanosis are addressed: lentiginosis, hyperpigmentation due to endocrine disorders or other systemic diseases, drug-induced hyperpigmentation. Acquired hypomelanoses include postinflammatory hypomelanosis, chemical depigmentation, idiopathic guttate hypomelanosis and punctate leucoderma. With reference to non-melanin pigmentation, the exogenous pigmentation due to chemicals, metals and drug exposure are discussed. The treatment is primarily based on finding the cause of the alterations to the pigment. The affected area, age and ethnic origin are also important factors. The spectrum of therapeutic options is broad: topical agents, chemical peeling, systemic agents, laser and light-based treatment. As some of these treatment procedures can have side effects, the availability of a protocol that contains information on the drug concentration, dose, parameters for laser treatment and the number of sessions is important. For every disorder the specific dermatological treatment is presented even when some pigmentation alterations that occur in association with systemic diseases, are cured by the treatment of the primary disease. Most diseases are exacerbated by exposure to UV light. Therefore, sun protection is recommended and a cosmetic coverage is indicated.

[Treatment of nevus of Ota and Ito and epidermal nevus syndrome]

Nevus of Ota, nevus of Ito and nevus of Hori are special melanocytic nevi that have a slate-brown or blue/grey coloring. They are pigmented disorders characterized by its heterotopic melanocytic dermal location and by blue/brown unilateral and sometimes bilateral facial patch in case of nevus of Ota, and in the supraclavicular, scapular, and deltoid region in case of nevus of Ito. It is more common in patients with Asian and dark-skinned ethnic backgrounds. Histologically, elongated, dendritic melanocytes are seen scattered mainly throughout the upper third of reticular dermis. An acquired variant is called Hori's nevus with more bilateral facial distribution, similar to melasma. Dermal melanocytosis can also occur elsewhere on the body, including inside the mouth. Despite its benign nature, patients frequently seek therapy because of its facial involvement. QS lasers are used effectively to treat these lesions. The number of treatment sessions correlates with clinical improvement. Post laser hypo- and hyperpigmentation are common side effects mainly affecting patients with darker skin.

Treatment of Laser-Responsive Dermal Pigmentary Conditions in Type III-IV Asian Skin With a 755-nm Picosecond Pulse Duration Laser: A Retrospective Review of Its Efficacy and Safety

BACKGROUND

Picosecond lasers have become very popular in the treatment of hyperpigmentation.

OBJECTIVE

Evaluating the efficacy and safety of picosecond 755-nm laser in treatment of nevi of Ota (NO) and Hori's nevi (HN) in Asians with Fitzpatrick skin Types III/IV.

METHODS

A retrospective review of patient records at the National Skin Center, Singapore, from 2015 to 2017. Three independent blinded dermatologists assessed pre-and-post treatment photographs using the physician's global assessment (PGA) score (0-clear, 1-almost clear, 2-mild, 3-moderate, and 4-severe).

RESULTS

There were 18 cases of NO and 11 cases of HN. Mean treatment sessions were 2.22 (NO; range 1–6) and 3.82 (HN; range 1–6). In the NO group, mean pre-and-post treatment PGA scores were 3.1 and 1.3, respectively (1.8 point change, p-value 0.0002), and average fluence used was 2.02 J/cm² (range: 1.02–2.38). In the HN group, mean pre-and-post treatment PGA scores were 2.6 and 1.1, respectively (1.5 point change, p-value 0.004), and average fluence was 2.08 J/cm² (range: 1.98–3.40). Eleven patients (37.9%) experienced postlaser erythema, and 1 (3.4%) patient developed transient postlaser hypopigmentation. No permanent hyper/hypopigmentation was seen.

CONCLUSION

The picosecond 755-nm laser is effective in the treatment of dermal pigmentary conditions in Asians with Fitzpatrick skin Types III/IV, with minimal risk of postlaser complications, and compared with the center's past experience with the Q-switched nanosecond 1064-nm laser, results in faster and more effective pigment clearance.

Dermatologic Laser Side Effects and Complications: Prevention and Management

The evolution of modern laser and light-based systems has mirrored the demand for clinically effective treatments and the need for safer technologies with reduced postoperative recovery, side effects, and complications. With each new generation of lasers, more selective tissue destruction can be achieved with reduced unwanted sequelae. Patient selection and preparation, operator technique, and expeditious recognition and management of post-treatment side effects are paramount in avoiding complications and patient dissatisfaction. An overview of important variables to consider for dermatologic laser treatments are presented in order to provide a framework to reduce the severity and duration of possible post-treatment side effects and complications.

Comparative Effectiveness of 755-nm Picosecond Laser, 755- and 532-nm Nanosecond Lasers for Treatment of Café-au-Lait Macules (CALMs): A Randomized, Split-Lesion Clinical Trial

BACKGROUND AND OBJECTIVES

Many types of lasers have been used to treat café-au-lait macules (CALMs) since the introduction of the selective photothermolysis theory. However, the efficacy and safety of picosecond lasers, compared with those of nanosecond lasers, have not been researched. To compare the efficacy and safety of 755 nm picosecond laser (PS-755 nm), Q-switched (QS) Alexandrite 755 nm nanosecond laser (QS-755 nm), and QS Nd:YAG 532 nm nanosecond laser (QS-532 nm) for treating CALMs.

STUDY DESIGN/MATERIALS AND METHODS

Forty-one patients received several treatments at 3-month intervals. Lesions were divided into two or three approximately equal parts, which were randomly treated with PS-755 nm, QS-755 nm, and QS-532 nm. The safety and efficacy of three lasers were determined based on blinded visual assessments and self-reports of patients three months after the comparative trial.

RESULTS

Visual assessment 3 months after the comparative trial revealed that there was no statistically significant difference among the sites treated by QS-755 nm (2.84 ± 1.11), QS-532 nm (2.63 ± 1.06), and PS-755 nm (2.74 ± 1.05) lasers. Five (26.32%) of 19 patients showed lesion recurrence. Adverse effects included acneiform miliaris, hypopigmentation, and hyperpigmentation, which were resolved within 12 months. Five (26.32%) of 19 patients who showed lesion recurrence 1-5 months after laser treatment had lightened or cleared at least 50% of the lesion. 46.67% of patients were satisfied or very satisfied with the outcome of the overall treatment.

CONCLUSIONS

PS-755 nm, QS-755 nm, and QS-532 nm laser treatments were equally effective in treating and improving CALMs. PS-755 nm caused fewer adverse effects. Individuals can react differently to different types of lasers. Patch tests should be conducted before the treatment. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Safety and Efficacy of a Novel 730 nm Picosecond Titanium Sapphire Laser for the Treatment of Benign Pigmented Lesions

BACKGROUND AND OBJECTIVES

Picosecond lasers in dermatology were originally focused on optimizing the removal of unwanted tattoos. Subsequent advances in this technology have expanded its clinical indications to include treatment of benign pigmented lesions, photodamage, melasma, and scar revision. In this retrospective review, we evaluate a novel 730 nm picosecond titanium sapphire laser in treating benign pigmented lesions.

STUDY DESIGN/MATERIALS AND METHODS

This is a retrospective review of all patients who presented to our institution between December 2019 and March 2020 for treatment of their benign pigmented lesions with a 730 nm picosecond titanium sapphire laser. All Fitzpatrick skin types (I-VI) were included. Absolute and relative evaluations were conducted by two blinded board-certified dermatologists using high-resolution photographic images.

RESULTS

Twenty-two of 64 patients satisfied inclusion and exclusion criteria. Patients received 1.1 ± 0.3 treatment sessions. The absolute average pigmentation score prior to treatment was 2.04 ± 0.7 versus 1.39 ± 0.6 after treatment (P < 0.05). Improvement in pigmentation was observed in 86% of the patients, while 3% had no improvement and 11% had worsening of pigmentation. No other adverse events were observed. Downtime consisted of 1-2 days of mild edema and erythema followed by 3-5 days of mild pigment darkening and superficial crust.

CONCLUSION

The novel 730 nm picosecond titanium sapphire laser is a safe and effective treatment for benign pigmented lesions. Future prospective randomized control studies would be beneficial to further clarify its role in the treatment of benign pigmentation. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Comparing the efficacy and safety of Q-switched and picosecond lasers in the treatment of nevus of Ota: a systematic review and meta-analysis

Nevus of Ota is cosmetically burdensome and often prompts patients to seek treatment. Lasers are commonly used in removing these lesions; however, no systemic analysis has been conducted to support a gold standard laser. To conduct a meta-analysis of the efficacy and safety of Q-switched Nd:YAG lasers (QSNL), Q-switched ruby lasers (QSRL), Q-switched alexandrite lasers (QSAL), and picosecond alexandrite lasers (PSAL) in removing nevus of Ota. Inclusion criteria were nevus of Ota patients treated with QSNL, QSRL, QSAL, or PSAL and documentation of percent clearance and the rate of at least one adverse event. Articles in English, Chinese, or Japanese were included. The prespecified outcome measures were efficacy (percent clearance) and safety (rates of hyperpigmentation, hypopigmentation, scarring, and recurrence). The review included 57 studies and 13,417 patients. The pooled success rate was 64% for QSNL (95% CI 52-76%), 54% for QSRL (95% CI 39-69%), 58% for QSAL (95% CI 44-72%), and 100% for PSAL (95% CI 98-102%). The pooled adverse event rate was 5% for QSNL (95% CI 4-6%), 14% for QSRL (95% CI 9-19%), 9% for QSAL (95% CI 6-12%), and 44% (95% CI 31-57%) for PSAL. QSNL has the most evidence for effectively and safely treating nevus of Ota. PSAL potentially has a superior efficacy; however, further studies are needed to elucidate its side effect profile when treating nevus of Ota.

Clinical improvement of photoaging-associated facial hyperpigmentation in Korean skin with a picosecond 1064-nm neodymium-doped yttrium aluminum garnet laser

Traditional attempts at alleviating photoaging-associated facial pigmentation conditions such as melasma, mottled hyperpigmentation, and post-inflammatory hyperpigmentation have yielded disfiguring cosmetic results. Laser toning using a low-fluence Q-switched 1064-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has been more commonly applied to date. However, the treatment efficacy and safety of this approach have not been widely reported. This study therefore evaluated the efficacy and safety of picosecond 1064-nm Nd:YAG laser application for photoaging-associated facial pigmentation treatment in Korean subjects. Forty-seven Korean subjects with photoaging-associated facial pigmentation underwent picosecond 1064-nm laser application. The clinical improvement of 17 patients was assessed by objective measurements such as melanin and erythema indices. All subjects received six biweekly treatments with the laser in a three-pass fashion delivering approximately 2000 to 2500 shots using a zoom handpiece with a spot size of 7 mm, fluence ranging from 0.4 to 0.7 J/cm², and a repetition rate of 10 Hz. Clinicians evaluated the improvement of pigmentation using the pigmentation area and severity index (PSI), and subjects reported their satisfaction level on a four-point scale. Statistical analyses were performed using the SPSS version 19.0 for Windows software program (IBM Corp., Armonk, NY, USA). Forty-seven subjects (45 females and two males) completed this study with a 12-week follow-up period. The average decrease in PSI value at 12 weeks after treatment was 6.85 ± 6.35 points (p < 0.001). The average decreases in the values of the erythema and melanin indices were 19.41 ± 64.64 points (p = 0.234) and 28.88 ± 32.89 points (p = 0.002). An analysis of 32 subjects' reports (68.1%) suggested good or excellent improvement. No serious adverse effects were observed during treatment or the follow-up period. Picosecond 1064-nm Nd:YAG laser application appears to be safe and effective in improving various photoaging-associated facial pigmentation conditions in Korean skin.

A Systematic Review of Picosecond Laser in Dermatology: Evidence and Recommendations

BACKGROUND AND OBJECTIVES

The use of picosecond laser in dermatology was originally focused on optimizing the removal of unwanted tattoos. Subsequent advances in this technology have broadened its clinical indications to include treatment of benign pigmented lesions, photodamage, melasma, and scar revision. In this systematic review, evidence-based recommendations are developed for the use of picosecond laser in dermatology.

STUDY DESIGN/MATERIALS AND METHODS

A comprehensive search of the English language literature was performed up to and including November 2019. Relevant citations were individually evaluated, synthesized, and categorized based on the Level of Evidence. With the addition of the authors' combined clinical experience, clinical recommendations were developed.

RESULTS

After application of inclusion and exclusion criteria, a total of 77 unique studies were evaluated. Treatment of benign pigmented lesions was associated with level I-IV evidence; rejuvenation was associated with level II evidence; melasma was associated with level II evidence; scar revision was associated with level II-III evidence; tattoo removal was associated with level I evidence.

CONCLUSION

Picosecond laser is a safe and effective treatment modality for an increasing range of dermatologic indications. Further development of this technology is warranted. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Successful and quick treatment of nevus of Ota with 755nm picosecond laser in Chinese

Nevus of Ota, also known as nevus fusco-caeruleus ophthalmo-maxillaris, is a benign dermal melanocytosis. In the past, this disease was usually treated by Q-switched laser therapy, but the course of treatment was relatively long. In recent years, it has been reported that 755nm picosecond laser, which was firstly reported to treat tattoos, is also effective in the treatment of nevus of Ota. Here, we report six cases of nevus of Ota which were treated with 755nm picosecond laser in Chinese people. We find amazingly that these lesions almost disappeared after only one or two sessions of treatment.

A Split-Face, Single-Blinded, Randomized Controlled Comparison of 532 nm Picosecond Neodymium-Doped Yttrium Aluminum Garnet Laser versus 532 nm Q-Switched Neodymium-Doped Yttrium Aluminum Garnet Laser in the Treatment of Solar Lentigines

Background

Solar lentigines are the most common form of benign epidermal pigmentation and one of the major cosmetic concerns in Korea. A 532 nm Q-switched neodymium: yttrium-aluminum-garnet (QSND) laser is typically used for the treatment, but the occurrence of post-inflammatory hyperpigmentation (PIH) is not rare. Recently, the use of picosecond (PS) lasers has emerged in pursuit of better outcomes.

Objective

To objectively compare the efficacy and safety of 532 nm PS and QSND lasers for the treatment of solar lentigines.

Methods

Twenty patients with solar lentigines were enrolled in a prospective, randomized split-face, single-blind study. One side of each face was treated using a 532 nm PS laser, and the other side using a 532 nm QSND laser. After one treatment, all patients were followed up for evaluation after 2, 4, 8, and 12 weeks. The clinical clearance was assessed by three blinded dermatologists using a 5-point quartile improvement scale (QIS). Subjective satisfaction, development of PIH, pain scale during treatment, and adverse problems were also recorded.

Results

Clinical clearance measured by QIS showed that the PS laser was more effective than the QSND laser. Subjective satisfaction and pain scale did not significantly differ between the two groups. The incidence of PIH was 5% in sides treated with the PS laser, and 30% with the QSND laser.

Conclusion

Both 532 nm PS laser and QSND laser were effective for the treatment of solar lentigines, but the PS laser was more effective with less PIH development.

Successful treatment of ephelides in Asian skin using the picosecond 785-nm laser

BACKGROUND

For ethnic skin, laser surgery for pigmented lesions presents a special challenge due to the increased risk of postprocedural complications-erythema, blistering, and postinflammatory dyspigmentation.

AIMS

To describe the treatment of ephelides in Asian skin treated with a picosecond 785-nm laser.

PATIENTS/METHODS

The first patient with ephelides on the cheeks and nose was treated with a picosecond 785-nm laser with the treatment parameter of 1.2 J/cm² and 3-mm spot size. The second patient with ephelides on the cheeks was treated with a picosecond 785-nm laser with the treatment parameter of 1.3 J/cm² and 3-mm spot size.

RESULTS

After a single laser session, both patients achieved appreciable improvement without any complications.

CONCLUSION

This is the first case series demonstrating the efficacy and safety of the picosecond 785-nm laser for the treatment of ephelides in Asian skin.

Evaluation of the Safety and Efficacy of a Picosecond Alexandrite Laser With DLA for Acne Scars in Chinese Patients

BACKGROUND AND OBJECTIVES

Recently, picosecond laser treatment has been used as an effective treatment for acne scars. To evaluate the efficacy and safety of a picosecond alexandrite laser with a diffractive lens array in the treatment of acne scars in Chinese patients.

STUDY DESIGN/MATERIALS AND METHODS

Patients with facial acne scars were treated with a picosecond alexandrite laser in three sessions at 4- to 6-week intervals and followed up for 2 months. Primary outcomes were measured by physicians' blinded evaluation of the acne scar using the ECCA (échelle d'éva physicians'luation clinique des cicatrices d'acné) grading scale. The secondary outcomes included the investigator global assessment (IGA) on the improvement of post-inflammatory erythema (PIE), patients' assessment of improvement on a 4-point scale and of satisfaction on a 5-point scale. Pain scores and adverse effects were also evaluated.

RESULT

Twenty patients with Fitzpatrick skin types III and IV were enrolled in the study and completed all treatment and follow-up visits. The mean ECCA scores fell from 197.75 ± 35.26 to 142.00 ± 35.92 (a 28% improvement), and the change was significant (P = 0.000). The mean IGA score of PIE improvement was 3.03 ± 0.75 (0 = no improvement and 4 = 76-100% improvement). On the basis of the patients' self-assessment, the average improvement scores were 2.30 ± 0.98 (0 indicating 0-25% improvement and 3 indicating >75% improvement). In total, 50% and 30% of the patients were "satisfied" and "very satisfied," respectively, with the treatment. The mean pain score was 3.20 ± 0.50 (0 = no pain, 10 = maximum pain) with topical anesthesia. The adverse effects included transient and mild erythema, edema, and scabbing.

CONCLUSIONS

Treatment with a picosecond alexandrite laser with a diffractive lens array is effective and safe for acne scars in Chinese patients. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Lasers for Becker's nevus

Becker's nevus is a common pigmented dermatosis, usually featured by ipsilateral pigmented patch with hypertrichosis. Becker's nevus is often treated with various types of lasers although other regimens are available. However, clinical outcomes appear inconsistent among studies. To summarize the clinical outcomes of Becker's nevus treated with lasers via literature review. A variety of lasers had been used alone or in combination to treat Becker's nevus. Laser wavelengths used for Becker's nevus ranged from 504 to 10,600 nm, while the number of treatment varied from 1 to 12 sessions. The clinical outcomes were mixed although combination of lasers with different wavelengths appeared to achieve a better efficacy. Adverse effects were usually mild to moderate erythema. While lasers are relatively safe, their efficacy for Becker's nevus is moderate. It seems that combination therapy could improve the outcome. However, trials in larger group of patients are required to validate the efficacy of each type of lasers for Becker's nevus.