An update on fractional picosecond laser treatment: histology and clinical applications

Activated melanocytes and senescent collagen fibers predict laser-treated melasma outcomes: An optical biopsy-based prospective cohort study

BACKGROUND

Melasma Area and Severity Index (MASI) score only assesses the pigmentation rather than photoaging. Picosecond alexandrite laser (PAL) with diffractive lens array (DLA) can improve photoaging and has been approved for melasma treatment. Prediction for post-laser outcome is limited.

OBJECTIVE

To in vivo compare the photoaging milieu altered by a PAL with DLA in melasma lesions and adjacent perilesions, and to delineate the predictive factors for outcomes.

METHODS

An optical biopsy with cellular resolution full-field optical coherence tomography (CRFF-OCT) was set up to evaluate the dynamic changes. Quantification was performed with the computer-aided detection (CADe) system.

RESULTS

The mean MASI score decreased significantly (p<0.001) in 12 of 15 patients but increased in the other three. An optical biopsy of 74,340 images showed the numbers of activated melanocytes and melanophages were significantly reduced post laser, and the basement membrane (BM) was repaired in melasma lesions, while basal lightening was noted in perilesions. The pre-treatment presence of activated melanocytes was associated with a high regional MASI score (p=0.013), while the senescent collagen fibers and activated melanocyte patterns were associated with less MASI score improvement (p=0.005). Senescent collagen fibers (p=0.002) and baseline BM damage(p=0.001) were strongly correlated to post-treatment melanophages. The baseline MASI score was not associated with activated melanocyte status or treatment outcomes.

CONCLUSION

Optical biopsy using CRFF-OCT revealed that patterns of activated melanocytes and senescent collagen fibers can serve as predictive markers for post-laser treatment outcomes. The photoaging characteristics of melasma were improved through the reduction of activated melanocytes and the repair of the BM.

Molecular insights into the effects of laser-induced optical breakdown (LIOB) after 1064 nm picosecond laser irradiation using a novel melanocyte-containing 3D skin model

Picosecond lasers use a mechanism known as laser-induced optical breakdown (LIOB). However, the underlying molecular mechanisms are not yet fully understood. The aim of this study was to gain insights into the molecular effects of LIOB using novel melanocyte-containing 3D skin models. Since the threshold of LIOB depends on the melanin content of the skin, we established a new human 3D skin model comprising melanocytes. Irradiation was done with a diffractive optical elements (DOE-) assisted fractional 1064 nm Nd: YAG picosecond laser utilizing the energy setting of 0.2 J/cm2, with a spot size of 7 × 7 mm and one pulse per area. In a further approach, we post-treated the models topically with a dexpanthenol-containing ointment. Examination was done histologically and using next-generation sequencing. The histological analysis revealed intra-epidermal vacuoles with an intact environment immediately after irradiation of the models and even after 24 h. Post-treatment with the dexpanthenol-containing ointment accelerated the repair processes in the models, with vacuoles no longer visible after 24 h. We found an upregulation of matrix metalloproteinases, collagens, heat shock proteins, cytokines and chemokines, reflecting repair mechanisms and tissue remodeling after picosecond laser irradiation. Initial stimulation effects of laser therapy were maintained even after topical dexpanthenol post-treatment. We present the first in vitro study investigating the effects of LIOB after 1064 nm picosecond laser irradiation using a novel standardized melanocyte-containing 3D skin model. LIOB-induced intraepidermal vacuoles promoted skin regeneration processes, which could be supported and accelerated by post-treatment with a dexpanthenol-containing ointment.

The Efficacy of 532/755 nm Laser Therapy for Facial Pigmented and Vascular Lesions: A Systematic Review and Meta-Analysis

Objectives: The increasing demand for aesthetic medical treatments has led to advancements in laser therapies, particularly for pigmented and vascular facial lesions. This study compares the efficacy of 532 nm and 755 nm lasers for treating facial pigmented and vascular lesions. Methods: Data extraction was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Primary outcomes included the (i) improvement and (ii) pain sensation. Secondary outcomes included the occurrence of adverse events. A random-effects meta-analysis was conducted for outcomes where two or more studies provided data. Continuous outcomes were analyzed using pooled standardized mean differences, while nominal outcomes were assessed using pooled risk ratios in endpoints, using observed cases only. Results: A total of 16 studies involving 509 participants were included. No significant difference in overall improvement between the 532 nm and 755 nm lasers was found. Subgroup analysis showed a slight advantage in the 755 nm group for lesion improvement (RR = 1.512, 95% CI [1.070, 2.136], p = 0.019). Adverse event occurrence was minimal, with no significant differences between the laser types, however the pain score was higher for the 532 nm laser (SMD = -1.336, SE = 0.636, 95% CI [-2.582, -0.09], p = 0.036). No publication bias with respect to any evaluated intervention was detected. Conclusions: This meta-analysis concludes that both 532 nm and 755 nm lasers are effective in treating facial pigmented and vascular lesions, with the 755 nm laser showing a slight advantage and the 532 nm one producing more painful experiences but fewer adverse events in the case of vascular lesions.

Efficacy and Safety of Poly-d,l-lactic Acid Delivered via a Transdermal Needle-free Microjet System for Enlarged Facial Pores

Enlarged facial pores are a common cosmetic concern influenced by factors such as age, genetics, and sebum production. Traditional treatments such as topical retinoids, chemical peels, and laser therapies often yield variable results and may involve discomfort or multiple sessions. We report the case of a 41-year-old Korean woman treated for visibly enlarged pores using poly-d,l-lactic acid delivered via a needle-free microjet system. This system uses advanced electromagnetic technology to create high-pressure microjets that penetrate the skin's outer layers, delivering therapeutic agents directly into the dermis. The patient underwent 5 monthly sessions, with significant improvements in pore size and skin texture observed within 4 weeks posttreatment. Clinical assessments showed a reduction in pore size from a baseline score of 6 to 3, sustained through 12 weeks posttreatment. The patient expressed satisfaction with the outcomes, reporting firmer, smoother skin with no adverse effects. Poly-d,l-lactic acid delivered via a microjet system was an effective, noninvasive treatment for enlarged facial pores in the treated patient. Further studies are needed to validate these findings and compare this approach with established therapies.

Comparison of 1064-nm Nd: YAG picosecond laser with fractional micro-lens array and electro-optical synergy for post-acne erythema: a prospective, randomized, split-face trial

Comparative data regarding the effectiveness of the 1064-nm Nd: YAG picosecond laser with fractional micro-lens array (P-MLA) versus traditional electro-optical synergy (ELOS) for treating post-acne erythema (PAE) are limited. Therefore, we aimed to compare the efficacy and safety of P-MLA and ELOS in the treatment of PAE. This prospective, randomized, split-face trial enrolled 20 patients with PAE, primarily of darker skin tones (Fitzpatrick skin types III-VI). Patients were randomly assigned to receive P-MLA treatment on one side of the face, and ELOS treatment on the other side. Three treatments were administered at 4-week intervals, with follow-up conducted at weeks 0, 4, 8, and 12. Standardized photographs were obtained using the VISIA system. Efficacy was assessed based on improvements in PAE lesion counts, clinical erythema assessment, VISIA skin analysis data, and patient-reported satisfaction. Adverse events were recorded. Both the P-MLA and ELOS groups showed significant reductions in erythema, with the P-MLA group demonstrating a notably greater decrease in PAE lesion counts and a higher clinical response rate at week 12 than the ELOS group. VISIA analysis revealed a greater reduction in red zone scores for the P-MLA group, alongside significant improvements in wrinkles and pigmentation. Patient satisfaction scores were comparable between the two groups, with an overall satisfaction rate of 94.74%. Adverse events, including erythema duration, edema, and pain, were similar across both groups, with no serious complications observed. P-MLA demonstrates superior efficacy and lower risk of adverse effects than ELOS in PAE treatment among Asian patients.

Paired Treatment Using Radiofrequency Microneedling and 755-nm Picosecond Laser With Fractionated Lens Array for Facial Rejuvenation

BACKGROUND

Patients frequently complain about fine lines, wrinkles, dyschromia, and photoaging, for which lasers and energy-based devices can treat each of these. Pairing various devices in a single treatment session can be safe and effective, but different technologies, mechanisms, histologies, parameters, and techniques must be considered.

OBJECTIVE

To examine the utility of a paired treatment regimen using radiofrequency microneedling and 755-nm picosecond laser with fractionated lens array to improve the clinical appearance of facial wrinkles and photoaging.

MATERIALS AND METHODS

A prospective clinical study investigated this paired treatment regimen using 4 monthly sessions.

RESULTS

Twenty-five subjects were enrolled, while 18 subjects completed 3-month follow-up. The mean age was 54 years, and 92% were women. Fitzpatrick Skin Types I to IV were represented. Assessments compared baseline with the 3-month follow-up. Two of 3 blinded reviewers agreed in identifying pretreatment and post-treatment photographs for 94.4% of cases. For physician Global Aesthetic Improvement Scale, 100% of subjects had clinical improvement. Overall, 88.9% of subjects were considered to be satisfied with their treatment. No serious or unanticipated adverse events occurred.

CONCLUSION

Paired treatment using radiofrequency microneedling and 755-nm picosecond laser with fractionated lens array can safely and effectively improve facial wrinkles and photoaging.

Picosecond Alexandrite Laser With Diffractive Lens Array Combined With Long-Pulse Alexandrite Laser for the Treatment of Facial Photoaging in Chinese Women: A Retrospective Study

BACKGROUND AND OBJECTIVES

Facial photoaging is a type of facial skin aging induced mainly by exogenous factors (ultraviolet radiation) and often manifests itself in the form of hyperpigmentation, telangiectasia, roughness, increase in fine lines/wrinkles, and enlarged pores. Recently, picosecond lasers have become an emerging option for the treatment of facial photoaging, and long-pulse alexandrite lasers (LPAL) have demonstrated promising potential in the treatment of photoaging-related symptoms. This study aimed to evaluate the efficacy and safety of picosecond alexandrite laser (PSAL) with diffractive lens array (DLA) combined with LPAL for facial photoaging.

METHODS

This is a retrospective study of 20 Chinese female patients with facial photoaging who received PSAL with DLA combined with LPAL during a 1-year period. All patients were treated every 4 weeks for a total of three treatments. Objective indicators of facial photoaging and patient satisfaction were evaluated before each treatment, and pain scores and adverse effects were recorded after each treatment.

RESULTS

Compared with baseline, patients showed significant differences in all facial photoaging indices (p < 0.01). After receiving three treatments, there was a 20.1% decrease in the pigmentation index, a 23.9% decrease in the erythema index, a 34.5% decrease in the texture index, a 28.4% decrease in the fine lines index, a 56% decrease in the pore index, a 9.3% elevation and a 17.1% decrease in elasticity R2 and F4, respectively, and a 55% decrease in sebum content. The mean satisfaction score for the three treatments was 4.67 (3.33, 5.00), and the mean visual analogue scale (VAS) pain score was 7.00. No serious adverse effects such as post-inflammatory hyperpigmentation (PIH), hypopigmentation, or blistering were observed at the treatment site during the treatment period.

CONCLUSION

PSAL with DLA combined with LPAL for the treatment of facial photoaging with significant efficacy, high patient satisfaction, and minimal adverse effects.

Advancements in laser technologies for skin rejuvenation: A comprehensive review of efficacy and safety

INTRODUCTION

Laser technology has fundamentally transformed the landscape of dermatology, offering nuanced solutions for skin rejuvenation and resurfacing. This paper aims to explore the spectrum of laser technologies, from ablative to non-ablative and fractional lasers, their mechanisms, benefits, and tailored applications for diverse skin conditions. As we delve into the intricacies of each technology, we also consider the scientific advancements that have made these treatments safer and more effective, promising a new horizon in skin rejuvenation.

OBJECTIVE

This comprehensive analysis seeks to evaluate recent advancements in laser technology for skin rejuvenation, focusing on efficacy, safety, and patient satisfaction.

METHODS

The selection criteria for studies in this publication focused on recent, peer-reviewed articles from the last 20 years, emphasizing advancements in laser technologies for skin rejuvenation. Our comprehensive review involved searches in PubMed, Cochrane, Scopus and Google Scholar using keywords like "skin rejuvenation," "laser technology," "efficacy," "safety," and "dermatology." This approach focused on inclusion of recent research and perspectives on the efficacy and safety of laser treatments in the field of dermatology.

RESULTS

Our literature review reveals advancements in laser skin resurfacing technologies, notably fractional lasers for minimal downtime rejuvenation, ablative lasers for precise tissue vaporization, and non-ablative lasers for coagulation effect promoting collagen with reduced recovery. Hybrid and picosecond lasers are highlighted for their versatility and effectiveness in addressing a wide array of skin concerns. The findings also emphasize the development of safer treatment protocols for ethnic skin, significantly reducing risks like hyperpigmentation and scarring, thus broadening the scope of effective dermatological solutions.

CONCLUSION

This extensive review of advancements in laser technologies for skin rejuvenation underscores a remarkable evolution in dermatological treatments, offering an expansive overview of the efficacy, safety, and patient satisfaction associated with these interventions. Furthermore, the exploration of combination treatments and laser-assisted drug delivery represents a frontier in dermatological practice, offering synergistic effects that could amplify the therapeutic benefits of laser treatments.

Laser-induced optical breakdown is a prior strategy for acquired melanin-increased disorder in dermal layer

This brief report discusses the challenges in treating dermal melanosis and the limitations of current laser treatments due to inadequate tissue penetration and potential side effects. It introduces laser-induced optical breakdown (LIOB) as a novel therapeutic approach using a picosecond laser with a diffractive lens array (DLA) to target dermal pigmentation effectively. LIOB induces multiphoton ionization, leading to melanin clearance through phagocytosis and apoptotic cell removal, while also promoting dermal remodeling and collagen synthesis. We present a case of successful treatment of dermal pigmentation in a 55-year-old woman using 755 nm-picosecond alexandrite laser therapy, demonstrating significant improvement without recurrence. The findings suggest that LIOB offers a promising solution for acquired dermal hypermelanosis by addressing both diffuse and localized pigmentation effectively, leading to skin rejuvenation with minimal downtime and high patient satisfaction.

Skin rejuvenation through topical application of indocyanine green with diffractive optical element mode of 785 nm picosecond laser in Asian females

BACKGROUND

Indocyanine green (ICG) exhibits robust absorption near 800 nm.

AIMS

To examine the clinical effects of combining ICG with a 785 nm picosecond laser for treating photo-aged skin.

PATIENT/METHODS

A 785 nm 600 picosecond laser was used on the facial area of 16 female patients with Fitzpatrick skin type III and IV (mean age: 58.44 ± 5.24 years) after applying 0.0125% ICG cream. A total of 3000 shots were administered in diffractive optical element mode at a pulse energy of 200 mJ and frequency of 10 Hz. Hyperpigmented lesions were treated using the Zoom handpiece set at a spot size of 3-4 mm, pulse energy of 60-120 mJ, and frequency of 3-7 Hz. Patients underwent five sessions of treatment at intervals of 1-2 weeks. Wrinkles, pores and pigmented lesions were assessed at the initial assessment and 4 weeks after the final treatment using the Modified Fitzpatrick Wrinkle Scale and 10-point visual analog scale, respectively. Skin biopsy of the postauricular area was performed on two consenting patients.

RESULTS

Significant improvements in wrinkles (p = 0.02), pores (p = 0.034), and hyperpigmentation (p = 0.036) were observed, along with increased patient subjective improvement. Adverse effects were transient and well-tolerated. Hematoxylin and eosin and Masson's trichrome staining revealed increased and thickened dermal collagen fibers. Immunohistochemical staining revealed increased expression of collagen I and III throughout the papillary and upper reticular dermis, along with diffuse increase of STRO-1 in the dermis.

CONCLUSIONS

The combined application of a 785 nm picosecond laser and ICG yielded promising clinical outcomes for treating photo-aged skin in Asian patients with Fitzpatrick skin type III and IV.

Fractional picosecond laser treatment of non-acne atrophic scars and scar erythema in Chinese patients

BACKGROUND

Fractional picosecond lasers (FPL) are reported to be effective and safe for atrophic acne scars and post-acne erythema. However, there is no evidence regarding the effectiveness and safety of FPL treatment for non-acne atrophic scars and scar erythema among Chinese patients.

METHODS

In this retrospective study, 12 Chinese patients with non-acne atrophic scars, including nine with scar erythema, were treated with one to three sessions of 1064 nm FPL treatment. Clinical improvement was objectively assessed through blinded evaluations by external physicians. A modified Manchester Scar Scale (mMSS) and the Clinician Erythema Assessment Scale (CEAS) were individually used to evaluate atrophic scars and scar erythema based on photographs. Physician-assessed and subject-assessed Global Aesthetic Improvement Scale (GAIS) were used to assess changes before and after FPL treatment. Patient satisfaction and adverse events were also documented.

RESULTS

Total mMSS scores, as well as three parameters (color, distortion, and texture), were significantly decreased after FPL treatment, with a mean reduction of 3.18 ± 1.60 in total scores (p < 0.05). The CEAS scores were significantly reduced from 2.41 ± 0.98 before treatment to 0.41 ± 0.40 at the final visit (p < 0.05). Based on physician-assessed and subject-assessed GAIS scores, 11 (91.7%) patients were improved after FPL treatment. 33.3% of patients were very satisfied, and 41.7% were satisfied. No serious, prolonged (> 3 weeks) adverse events were observed.

CONCLUSION

Our study suggests that 1064 nm FPL treatment may be a promising option for non-acne atrophic scars, especially with scar erythema. Further studies are needed to confirm our results.

Laser-mediated Solutions: Breaking Barriers in Transdermal Drug Delivery

Skin diseases pose challenges in treatment due to the skin's complex structure and protective functions. Topical drug delivery has emerged as a preferred method for treating these conditions, offering localized therapy with minimal systemic side effects. However, the skin's barrier properties frequently limit topical treatments' efficacy by preventing drug penetration into deeper skin layers. In recent years, laser-assisted drug delivery (LADD) has gained attention as a promising strategy to overcome these limitations. LADD involves using lasers to create microchannels in the skin, facilitating the deposition of drugs and enhancing their penetration into the target tissue. Several lasers, such as fractional CO2, have been tested to see how well they work at delivering drugs. Despite the promising outcomes demonstrated in preclinical and clinical studies, several challenges persist in implementing LADD, including limited penetration depth, potential tissue damage, and the cost of LADD systems. Furthermore, selecting appropriate laser parameters and drug formulations is crucial to ensuring optimal therapeutic outcomes. Nevertheless, LADD holds significant potential for improving treatment efficacy for various skin conditions, including skin cancers, scars, and dermatological disorders. Future research efforts should focus on optimizing LADD techniques, addressing safety concerns, and exploring novel drug formulations to maximize the therapeutic benefits of this innovative approach. With continued advancements in laser technology and pharmaceutical science, LADD has the potential to revolutionize the field of dermatology and enhance patient care.

Combining large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers for promoting protective melanosome autophagy via the PI3K/Akt/mTOR signalling pathway for the treatment of melasma

Melasma is a common condition of hyperpigmented facial skin. Picosecond lasers are reported to be effective for the treatment of melasma. We aimed to identify the most effective therapeutic mode and elucidate the potential molecular mechanisms of picosecond lasers for the treatment of melasma. Female Kunming mice with melasma-like conditions were treated using four different picosecond laser modes. Concurrently, in vitro experiments were conducted to assess changes in melanin and autophagy in mouse melanoma B16-F10 cells treated with these laser modes. Changes in melanin in mouse skin were detected via Fontana-Masson staining, and melanin particles were evaluated in B16-F10 cells. Real-time polymerase chain reaction and western blotting were used to analyse the expression levels of melanosome and autophagy-related messenger ribonucleic acid (mRNA) and proteins. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers resulted insignificant decreases in melanin as well as in mRNA and protein expression of melanin-synthesizing enzymes (TYR, TRP-1 and MITF). This combination also led to increased expression of the autophagy-related proteins, Beclin1 and ATG5, with a marked decrease in p62 expression. Intervention with the PI3K activator, 740 Y-P, increased TYR, TRP-1, MITF, p-PI3K, p-AKT, p-mTOR and p62 expression but decreased the expression of LC3, ATG5 and Beclin1. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers proved more effective and safer. It inhibits melanin production, downregulates the PI3K/AKT/mTOR pathway, enhances melanocyte autophagy and accelerates melanin metabolism, thereby reducing melanin content.

Advancements in Laser Therapies for Dermal Hyperpigmentation in Skin of Color: A Comprehensive Literature Review and Experience of Sequential Laser Treatments in a Cohort of 122 Indian Patients

The heightened awareness of ethnic dermatology aligns with the growing prevalence of skin of color communities globally, where hyperpigmentation disorders pose a common dermatological challenge. Effectively addressing dermal pigmentation is challenging due to its resistance to conventional therapies and its association with impaired quality of life. This underscores the need for effective treatments and a thorough grasp of laser advancements. A relevant literature search spanning the last 7 years across the PubMed database reveals core studies, challenges, and the evolution of laser technologies tailored for various forms of congenital and acquired dermal hyperpigmentation in skin of color. This comprehensive review explores the mechanisms, applications, and recommendations for pigmentary laser technologies, highlighting the key role of Q-switched lasers in their established millisecond/ nanosecond forms and emerging picosecond lasers, fractional non-ablative and ablative lasers, Intense Pulsed Light, etc. The summary of evidence includes studies on dermal melanocytosis (nevus of Ota and Hori's nevus), tattoos, acquired dermal macular hyperpigmentation, etc., and also entities with mixed epidermal-dermal components, such as melasma and post-inflammatory hyperpigmentation. The review offers valuable insights for clinicians to make informed decisions based on diagnosis, skin type, and the latest technologies to optimize results and minimize complications, especially in darker Fitzpatrick skin types. In their five-year study with 122 Indian patients, the authors applied specific laser combinations for diverse dermal melanoses, including tattoos, dermal/mixed melasma, acquired dermal macular hyperpigmentation, and dermal nevi. Substantial pigmentation reduction, subjectively assessed by both physicians and patients, was observed across all groups. A one-way ANOVA indicated a significant difference in mean improvement scores across various pigmentary conditions (F = 3.39, p = 0.02), with melasma patients exhibiting a significantly higher improvement score than tattoos (p = 0.03). The results affirmed the safety and efficacy of sequential laser therapy for dermal pigmentation in skin of color, advocating for flexibility in approach while maintaining the rationale behind the laser sequences. Despite advancements, challenges persist, and gaps in the current literature are identified. In conclusion, this summary highlights the ongoing pursuit of optimal protocols in dermatological laser treatments for dermal melanoses, offering valuable insights for future research and clinical practice.

Efficacy and safety of 1064-nm fractional picosecond laser for the treatment of postmastectomy scars in transgender men: A randomized controlled trial

OBJECTIVES

Subcutaneous mastectomy is a crucial component of gender affirmation therapy for transgender men (TM), but the scars that result from this procedure can frequently impair their quality of life. This study aimed to assess the efficacy and safety of 1064-nm fractional picosecond laser (FxPico) treatment for hypertrophic and atrophic postmastectomy scars in TM.

METHODS

Twenty-two patients with a total of 35 pairs of bilateral symmetric mastectomy scars were enrolled. One of each pair of symmetric scars was randomly assigned to receive four FxPico treatments at 4-week intervals. All scars were evaluated using the modified Vancouver Scar Scale (mVSS) and three-dimensional imaging for scar roughness, melanin index, and hemoglobin index before each treatment session and at 1, 3, and 6 months following the last treatment. Additionally, participant-rated scar satisfaction (PSS) and scar improvement (Global Assessment Score, GAS), as well as adverse events were recorded.

RESULTS

During the 6-month follow-up period after the end of laser treatment sessions, the treated scars showed significant reductions in the mVSS compared to the untreated controls (p < 0.001), whereas the melanin index and hemoglobin index were not significantly different. Subgroup analysis of hypertrophic scars demonstrated statistically significant reductions in mVSS at 1 (p = 0.003) and 3 months (p = 0.041) after the end of laser treatments. PSS was significantly higher on the laser-treated scars than the controls (p = 0.008), and a participant-rated GAS of 2.95 ± 0.65 was found. There were no serious adverse events reported.

CONCLUSIONS

1064-nm FxPico could be utilized to treat mastectomy scars among TM, particularly the hypertrophic type.

Picosecond Nd:YAG versus Fractional CO2 Lasers in Management of Postburn Scars

Background

The picosecond laser was primarily designed to enhance tattoo removal. Because it has a new innovative mechanism for energy delivery, it has been modified to be used in other conditions such as skin resurfacing, which was usually treated with fractional CO2 laser. Comparing both technologies in managing postburn scars has not been widely addressed.

Methods

The current prospective comparative randomized intrapatient study was done on 15 patients who presented with unsightly postburn scarring. As a split study, one-half of the affected areas were treated using the picosecond Nd: YAG laser. The other areas were treated with a fractional CO2 laser. After three treatment sessions, the results were analyzed both objectively and subjectively.

Results

The assessment by the image analysis system (Antera camera) showed improvement in all the parameters in both groups. The melanin relative variation decreased from 11.65 ± 2.86, 15.85 ± 5.63 to 10.60 ± 1.96, 12.56 ± 3.98, respectively in picosecond laser sites and fractional CO2 sites. The percentage change in overall opinion decreased in in favor of the fractional CO2 laser sites, which is a statistically significant improvement. Instead, color scores revealed a greater reduction in the picosecond sites in comparison with the fractional CO2 sites, as it decreased from 7.67 ± 1.76, 7.73 ± 1.83 to 2.87 ± 1.06, 6 ± 1.2, respectively.

Conclusions

When compared with fractional CO2 lasers, picosecond Nd:YAG shows comparable improvements in scars' erythema, texture, and height, with some superiority in the management of hyperpigmented scars.

Comparison of 755-nm picosecond alexandrite laser versus 1064-nm Q-switched Nd:YAG laser for melasma: A randomized, split-face controlled, 2-year follow-up study

OBJECTIVES

Pulsed laser treatment of melasma has shown some promising results. To compare the effectiveness and safety of 755-nm picosecond alexandrite laser (PSAL) fitted with diffractive lens array (DLA) versus 1064-nm Q-switched neodynimum:yttrium aluminum garnet laser (QSNYL) for the treatment of melasma.

METHODS

We conducted a randomized, split face controlled, 2-year follow-up study. Each face was divided into two parts, each side receiving three treatments with either PSAL or QSNYL at 1 month intervals. Modified Melasma Area Severity Index scores (mMASI), pain scores, patient satisfaction and adverse events were recorded. In vivo reflectance confocal microscopy (RCM) images were acquired.

RESULTS

Twenty subjects were enrolled and three dropped out. At 6 months, mMASI scores were significantly lower than baseline for QSNYL sides (p = 0.022), with no statistically significant difference between PSAL sides before and after treatment, PSAL sides versus QSNYL sides, or patient satisfaction scores. QSNYL treatment was associated with less pain (p = 0.014). No serious adverse events were reported. In the PSAL sides RCM showed a large number of dendritic melanocytes infiltrated in the dermis at 2 weeks and 4 weeks after treatment. Ten patients (58.82%) reported recurrence or exacerbation at 2-year follow-up with no statistically significant difference between the two lasers.

CONCLUSIONS

QSNYL demonstrated short term clinical efficacy for melasma, but did not provide any additional benefit compared to PSAL with DLA. QSNYL was associated with less pain. There was a high recurrence rate at 2-year follow-up. RCM allowed the detection of cellular changes in melasma lesions.

Advances in laser therapies for the scar

Scars are classified into 5 types: Superficial scars, hypertrophic scars, atrophic scars, depressed scars, and keloid. These types are primarily characterized by abnormal production of fibroblasts and collagen, as well as the disorderly arrangement of connective tissue. Laser treatment for scars involves the coordinated activation of various signaling pathways and cytokines. However, the exact pathological mechanism for scar formation remains unclear, leading to a lack of radical treatment. Recently, laser treatment has gained popularity as a new minimally invasive approach for scar treatment. The emergence of new theories such as fractional, picosecond laser, and laser-assisted drug delivery has led to continuous advance in laser treatment. Up to now, it has been developed numerous novel treatments, including combined with drug, physical, and other treatments, which have shown superior therapeutic effects. In order to optimize laser treatment in the future, it is crucial to combine new materials with postoperative care. This will help clinicians develop more comprehensive treatment strategies. Therefore, it is important to explore treatment options that have broader applicability.

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.