Lasers In Dermatology Research Articles

Efficacy and adverse reactions of fractional CO2 lasers for treating papular acne scars: a retrospective study of 35 patients.

Papular acne scars are a special type of acne scar, and the prevalence and treatment of this disease have rarely been reported in the literature; moreover, the prevalence of this disease is often neglected, and treatment is difficult. Our study revealed a high prevalence of this type of acne scar in the clinic and explored an effective and safe method. This retrospective study aimed to analyse the prevalence of papular acne scarring among patients attending our Dermatology Laser Clinic and evaluate the clinical efficacy of fractional CO2 lasers. We retrieved the data of 370 patients with acne scarring who visited our hospital between April 2021 and November 2022 and analysed the prevalence of papillary acne scarring among them. Among these patients, 35 underwent CO2 laser treatment using an artificial grid pattern. A total of three treatments were administered, with a two-month interval between each session. Scar assessment was conducted using the Global Scar Scale (GSS) and the Acne Scar Clinical Assessment (ECCA) scale, along with physician visual evaluation and patient satisfaction surveys, both before the first treatment and one month after the final treatment. Adverse reactions were recorded during follow-up visits after each treatment. Among the 370 patients with acne scarring, 128 exhibited papular acne scarring, resulting in a prevalence rate of 34.6%. Among them, 37.5% were male and 32.6% were female. A total of 90.6% of patients had combined other types of acne scarring, while 9.4% had papular acne scarring exclusively. Following CO2 laser grid treatment, there was a significant reduction in GSS scores and ECCA values, accompanied by a noticeable improvement in physician visual evaluation and patient satisfaction scores. Papular acne scarring has a relatively high incidence rate, and there is no significant sex difference. It often coexists with other types of acne scarring. CO2 laser treatment using an artificial grid pattern effectively improved papular acne scarring with a good safety profile.

Comparing Line-Field Confocal Optical Coherence Tomography and Reflectance Confocal Microscopy on the In Vivo Healing Process of Lesions Induced by Fractional Photothermolysis.

The advent of ablative fractional photothermolysis has revolutionized laser dermatology by providing a method to produce well-standardized, precise, and repeatable microscopic lesions. These wounds typically heal within 1-3 weeks, depending on the body site, with a minimal risk of permanent scarring. This positions ablative fractional photothermolysis as an exemplary in vivo model for studying the skin's wound healing processes. This study aims to evaluate and compare the effectiveness of two noninvasive imaging techniques, reflectance confocal microscopy (RCM) and line-field confocal optical coherence tomography (LC-OCT), in assessing skin wound healing following microscopic injuries induced by ablative fractional photothermolysis. The forearms of participating volunteers were treated and ablated with a CO2-Laser in a fractional pattern using varying power settings (2.5-10 mJ/MTZ). In vivo RCM and LC-OCT images were obtained at predefined time intervals post-laser treatment, ranging from 6 h to 14 days. Vertical visualization of the lesions through both imaging modalities revealed a healing process characterized by the upward and outward movement of microscopic epidermal necrotic debris, thereby reducing the depth of the injury while forming an external crust. LC-OCT imaging demonstrated more comprehensive results with fewer movement artifacts. Conversely, horizontal visualization with both techniques highlighted a gathering of keratinocytes around the wounds, indicating the initiation of the regenerative process. RCM provided superior image clarity in this horizontal plane. RCM and LC-OCT offer valuable and complementary noninvasive alternatives to conventional biopsy methods for the assessment and characterization of the skin's wound healing process post-ablative fractional photothermolysis. These findings underscore the potential of such imaging techniques in enhancing our understanding of the wound healing process. ClinicalTrials.gov identifier: NCT05614557.

A novel coaxial air-R134a spray cooling for heat transfer enhancement of laser dermatology

Efficient cooling is essential in laser dermatology to prevent thermal damage, but current methods are often hindered by thermal barrier film deposition. This study presents coaxial air-R134a spray cooling for heat transfer enhancement and deposited-film mitigation. Surface temperature was measured using a TFTC thermocouple, while heat flux was estimated through the improved Duhamel theorem. High-speed camera visualization with the Mie-scattering technique captured the spray and film behavior. The results showed uniform and effective cooling via transient surface heat transfer and film behaviors. The boiling curve identified three distinct cooling phases: transition boiling, nucleate boiling, and single-phase film deposition. Airflow adjustments not only enhance the heat transfer coefficient but also control spray dynamics, droplet rebounding, and film spreading. Self-organizing maps revealed that medium-to-high nozzle spacing (y/D) reduces surface temperature and increases the heat transfer coefficient. Film resistance time is minimized by either high airflow and low y/D or low airflow and high y/D. For critical heat flux, low y/D and airflow are optimal. A y/D = 32 and 60 L/min airflow provided appropriate operating conditions. However, airflow increased frost deposition during off-duty, suggesting moisture-free air in the future.

Efficacy of Nd:YAG Laser 1064-nm in the Treatment of Onychomycosis.

To assess the effectiveness of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser 1064 nm in the management of onychomycosis. Descriptive observational study. Place and Duration of the Study: Department of Dermatology, PNS Shifa Hospital, Karachi, Pakistan, from December 2022 to May 2023. Thirty patients, of either gender, aged between 20 and 60 years, with a clinical diagnosis and a positive KOH test for onychomycosis. Long-pulsed 1064-nm Nd:YAG laser therapy was administered to patients. On the basis of nail plate thickness, laser therapy was given once a week for a month at a speed of 25 mm/sec and a spot diameter of 4 mm, with fluencies ranging from 40 - 60 J/cm2. Before and six months' post-treatment, the patients' photos were taken and were evaluated based on dermoscopic results and clinical improvement. The patients' average age was 40.20 ± 15.85 years, and their average duration of disease was 3.0 ± 1.41 years. Six (20%) were males and 24 (80%) cases were females. The most prevalent clinical type was distolateral subungual onychomycosis 22 (73%). Fourteen (46.6%) cases showed excellent improvement, 6 (20%) cases showed good improvement, and 10 (33.3%) cases showed mild improvement. Long-pulsed Nd:YAG laser is a safe and efficient option for onychomycosis because of its high clinical cure rates, lack of side effects, and clinical therapeutic efficacy. Onychomycosis, Nd:YAG laser 1064-nm, Dermatology, Nail, Lasers in dermatology.

Complications of dermatologic lasers in high Fitzpatrick phototypes and management: an updated narrative review.

This article explores the intricacies of laser surgery, acknowledging inherent risks and complications. Patients with higher Fitzpatrick phototypes, characterized by unique biological traits, face heightened vulnerability during laser treatments. Limited experience with darker skin tones necessitates a higher level of laser expertise and a conservative approach. The study aims to comprehensively review laser therapy's side effects and complications, with a specific focus on Fitzpatrick phototypes IV through VI. We searched the MEDLINE database from 1972 to 2023 to consolidate knowledge. Results illuminate nuanced challenges associated with laser surgery in higher phototypes. In conclusion, this research emphasizes the need for enhanced expertise and caution in laser procedures for individuals with darker skin, offering valuable insights to optimize patient safety and outcomes.

Use of Low Level Laser in Cosmetic Dermatology

Use of Low Level Laser in Cosmetic Dermatology

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.

Intermittent cryogen spray cooling coupled with cold air jet for heat transfer enhancement and cryogen saving of laser dermatology

Laser dermatology has become a convenient technique for medical treatment. However, the epidermal temperature could be increased, leading to intolerable side effects. Cryogen spray cooling (CSC) is implemented to decrease epidermal damage, but the current CSC could increase cryogen wastage. In this study, the CSC is coupled with a cold air jet (CAJ) and is further subjected to intermittent strategy (ICSC) to mitigate film deposition, enhance heat transfer, and save cryogen consumption, through CAJ-to-spray interaction. The surface temperature is measured by a thin film type-T thermocouple, while the heat transfer is estimated by enhanced Duhamel theorem. The film intensity is captured by a digital single-lens reflex camera through the scattering-illumination technique. The results affirmed the benefits of using ICSC/ICSC-CAJ for laser dermatology. It demonstrated lower surface temperature, film intensity, and film resistance as well as higher convection and efficiency compared with CSC. ICSC-CAJ showed the lowest minimum temperature (1.8%–4.9% decrement) and film resistance (3.8%–17.5% decrement), the highest average convective coefficient (84%–92% increment) and efficiency (7%–9% increment) compared with ICSC. Lower frequency and moderate duties would be preferable for ICSC, while higher frequency and lower duties would be preferable for ICSC-CAJ. The efficiency increased with the saving (110% increment), which insights into our understanding of alternative enhancement toward cryogen saving strategy.

Transient behavior of liquid film deposition and surface heat transfer upon cryogen-spray cooling coupled with cold air jet

Cryogen spray cooling (CSC) has become a promising auxiliary-cooling technique for laser dermatology, which recently enhanced by cold air jet (CSC-CAJ). However, the CAJ-to-spray interactions could worsen the CSC performance and associated liquid film behavior. In this study, the transient behavior of liquid film deposition and surface heat transfer of CSC-CAJ was investigated. A high-speed camera was used to capture the film intensity through Mie-scattering technique. Fast-response TFTC thermocouple was used to measure the transient surface temperature. The large eddy simulation (LES) was used to extract the vortical structure, while the discrete-phase model (DPM) and Eulerian wall film (EWF) were coupled for the spray process and the transient film modeling. The results showed that the CAJ significantly enhanced CAJ-to-spray mixing and mitigated the film thickness (i.e., 32 % reduction). The CSC-CAJ had asymmetric film coverage due to induced counter-rotating vortex-pairs (CRVP) from the CAJ-to-spray interaction, which laterally clustered the spray. It permitted fast evaporation with dominant CAJ at the spray-periphery while permitting fast evaporation with dominant spray at the spray-core. Consequently, the CSC-CAJ showed 75 % temperature increment at the windward side and 15 % temperature reduction with 60 % heat transfer coefficient enhancement at the impingement point. The experimental film intensity and simulated film thickness were linearly correlated and significantly influenced the surface temperature. The combined results affirmed the significant impact of the CAJ on the transient film deposition, which potentially helps promote advanced cooling technology.

Evaluation of Wrinkle and Dermal Thickness in the Forearm before and after Picosecond Laser Therapy.

Skin wrinkles are generated as a result of the aging process. Dermal thickness underneath a wrinkle decreases absolutely. Approximately 20% of dermal thickness disappears as people become elderly. In recent times, people have attempted to reduce wrinkles using various procedures. Currently, available picosecond lasers in dermatology can create mechanical stress and the energy can be fractionated via diffractive lens arrays (DLA). An emerging indication for the picosecond laser includes photorejuvenation. Non-ablative laser skin rejuvenation therapy demonstrates the dermis can be safely reconstructed by only irradiating the skin surface with a laser. The clinical effects of picosecond pulse laser have been frequently reported, but few studies have included histological investigation. This study aimed to evaluate wrinkle and dermal thickness in the forearm before and after picosecond laser therapy. Twenty healthy male and female subjects between 36 and 55 years old with wrinkles in the forearm who met the sample requirements and were willing to participate were recruited in this study. Clinical examination and biopsy for histopathological examination were carried out before and 4 weeks after therapy, then treatment was carried out using a picosecond laser. At 1-month follow-up, a significant improvement was noted in wrinkle and dermal thickness (P < 0.05). This picosecond 755 nm alexandrite laser with DLA was found to be very effective in treating wrinkles, which was confirmed by a dermatologic assessment from forearm photographic assessment scaled and dermal thickness improvement.

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.

Unstable spray pattern and cooling performance of cryogen spray coupled with cold air jet: An experimental study

This study focuses on the interactions between cryogen spray cooling (CSC) and cold air jet (CAJ), as well as the heat transfer performance upon CAJ-CSC impingement assisted for laser dermatology. CAJ is found to collapse downstream spray on the windward side, enhancing fluctuations of R1234yf spray width. Standard deviation (SD) distribution identifies that fluctuations at nozzle exit are attributed to ambient-to-spray interactions, which is also confirmed by the proper orthogonal decomposition (POD) analysis. The third POD mode highlights jet-to-spray interactions on the windward side of spray, yielding an enhanced instability by 1.72 times when CAJ flow rate (Q) increases from 4 to 8 m3/h. The closer location to the spray center on the same radial side corresponds to a faster thermal response and a lower temperature drop (ΔT). ΔT on the windward side decreases due to the considerable CAJ-induced droplet swarm drift. The heat transfer degrades on the leeward side due to the thermal gas boundary layer originating from the inclined CAJ sweep. Nevertheless, the CAJ with a small flow rate (4 m3/h) enhances the heat transfer at spray center, yielding a minimum surface temperature of −32.3 °C. Comparative investigation indicates R134a has superior cooling performance but more significant instabilities inside spray plume. R1234yf serves a relatively stable sub-cooling region within a radial distance of ±1 mm from spray center characterized by low spray fluctuations and high temperature drops at Q = 4 m3/h. Substitution of R1234yf for R134a still needs heat transfer enhancement for clinical considerations.

Application of Picosecond Laser in Dermatology

ABSTRACT Background: Lasers are one of the most important treatment modalities in dermatology. Lasers interact with chromophores through several mechanisms that depend on fluence and pulse durations. Early lasers worked by photothermal interaction with pulse durations of 1 microsecond to 1 second. A picosecond laser is developed to confine photothermal effects and produce photomechanical effects and plasma induction. Purpose: To understand the mechanism of action and application of picosecond lasers for dermatological disorders. Review: Non-fractional picosecond lasers work by photomechanical interaction. Photomechanical interaction happens when pulse duration is less than inertial confinement time, causing fractures of chromophores with lower energy, or “cold ablation”. Fractional picosecond lasers work by laser-induced optical breakdown (LIOB). In LIOB, accelerated seed electrons cause an electron avalanche that produce a collection of free electrons called plasma, which ablates tissues. LIOB in the skin is always followed by photodisruption. In LIOB, vacuoles and debris were eliminated transdermally and dermal collagen and elastin increased. Picosecond laser may be applied in disorders requiring destruction of chromophores and for collagen and elastin disorders. It is currently the first-line treatment for tattoo removal (Nevus of Ota and Acquired Bilateral Nevus of Ota-like macules, or ABNOM). It has good efficacy and safety for solar lentigines, freckles, and cafe-au-lait macules (CALM). It is an additional treatment for moderate to severe melasma and hypertrophic scars, in combination with other treatments. The fractional picosecond laser showed moderate improvement and low risk of postinflammatory hyperpigmentation (PIH) for atrophic acne scars and produced improvement in striae alba.

Picosecond lasers in dermatology

The picosecond laser is one of the latest laser systems in dermatology and was originally developed to optimize tattoo removal. Advances in this technology has expanded the use of the picosecond laser to numerous other indications. This article provides an overview of the technical background as well as the indications of the picosecond laser in dermatological laser medicine and elucidates the possibilities and limits of this laser system. The article is based on areview of the current literature as well as experience from clinical practice in auniversity laser department. The picosecond laser enables aparticularly gentle and effective treatment due to ultra-short pulses and the principle of laser-induced optical breakdown. Compared to Q‑switched lasers, the picosecond laser has fewer side effects and is associated with lower pain intensity and shorter downtime. In addition to the removal of tattoos and pigmentary disorders, it is also used in the treatment of scars and rejuvenation. The picosecond laser has awide range of indications in dermatological laser medicine. The current data indicate that the laser is an effective method with few side effects. Further prospective studies have to be conducted to assess the efficacy, tolerability and patient satisfaction in an evidence-based manner.

Thermal eye injuries from dermatologic laser treatments—an experimental study

In recent years, severe ocular complications after dermatological laser therapies have been reported. One hypothesis is thermal damage due to heating of the metal eye shields. The aim of the present study is to evaluate the safety of ocular metal eye shields during laser therapy of the periocular region. For the experimental study, porcine eyelids were exposed to continuously increasing laser energy and multiple pulses using a number of dermatologic laser systems. Temperature differences of the convex and concave surface of metal eye shields were constantly measured using a thermocouple. Maximum increase of the convex surface of shields was + 8.9 °C (± 0.1 °C) provided by the long-pulsed alexandrite laser (20–25-J/cm2 energy, 15-mm spot size, 20-ms pulse duration, 1 Hz). Present data indicate that metal eye shields provide sufficient thermal protection when clinically used laser parameters are applied. Other safety precautions continue to be essential to protect both the patient and the laser operator. These include the use of nonreflective metal eye shields, precise knowledge of laser physics, and a clear understanding of how they interact with ocular and periocular anatomy.

Use of surgical lasers in small animal dermatology

Background: Use of lasers in veterinary medicine has significantly increased over the past decade. What was once a piece of equipment, almost exclusively used by veterinary specialists, has now become a common piece of equipment in general veterinary practices. It is imperative to know the appropriate situations and diseases for which lasers can be used.Aim of the article: This article covers the basics of lasers, including discussion of both diode and CO2 lasers. It also discusses several skin diseases and/or conditions in which lasers are commonly used.

Perceptions of Professionalism and Preferences on Social Media in 2022.

*Department of Dermatology, UC Davis, Sacramento, California †Cosmetic Laser Dermatology, San Diego, California ‡Department of Dermatology, University of California, San Diego, California The authors have indicated no significant interest with commercial supporters.

Nonablative Fractional Laser Treatment Is Associated With a Decreased Risk of Subsequent Facial Keratinocyte Carcinoma Development.

Keratinocyte carcinoma (KC) is the most common type of nonmelanoma skin cancer. Currently, prophylactic treatment options are limited. Nonablative fractional lasers (NAFL) have received the Food and Drug Administration approval for the treatment of actinic damage; however, their role in KC prophylaxis is not known. The aim of this study is to determine whether NAFL treatment is associated with a decrease in subsequent facial KC development. A retrospective cohort study of patients with a history of facial KC treated at the Massachusetts General Hospital Dermatology Laser and Cosmetic Center between 2005 and 2021 was conducted. Forty-three NAFL-treated patients with a history of facial KC and 52 matched control subjects were included in the study. The rate of subsequent facial KC development was 20.9% in NAFL-treated patients and 40.4% in control subjects (RR 0.52, p = .049). Control subjects developed new facial KC significantly sooner than NAFL-treated patients (p = .033). When controlling for age, gender, and skin type, control subjects were more likely to develop new facial KC than NAFL-treated patients (hazard ratio 2.65, p = .0169). NAFL treatment was associated with a decreased risk of subsequent facial KC development and may have a benefit for KC prophylaxis.

Needs and Gaps in Resident Trainee Education, Clinical Patient Care, and Clinical Research in Cosmetic Dermatology: Position Statement of the Association of Academic Cosmetic Dermatology.

Cosmetic dermatology is a key subspecialty of academic dermatology. As such, academic centers are expected to demonstrate excellence in the teaching of cosmetic dermatology skills to trainees, the clinical delivery of cosmetic dermatology services to patients, and the performance of clinical research that advances knowledge and uncovers new therapies in cosmetic dermatology. The Association of Academic Cosmetic Dermatology (AACD), a newly formed medical professional society, includes as its principal aims the support of all of these areas. AACD is comprised of group of board-certified dermatologists who teach cosmetic and laser dermatology at US dermatology residency programs. An expert panel constituted by the AACD recently convened a workshop to review gaps pertaining to academic cosmetic dermatology. This panel considered needs and potential corrective initiatives in three domains: resident education, patient experience, and clinical research. The work of the panel was used to develop a roadmap, which was adopted by consensus, and which will serve to guide the AACD moving forward.

The Association of Academic Cosmetic Dermatology: improving cosmetic dermatology education through collaboration, research, and advocacy.

Cosmetic and laser procedures are increasingly popular among patients and are skills in which dermatologists are regarded as well trained. Most dermatology residents intend to incorporate cosmetic procedures into their practice and prefer to learn such procedures during residency through direct patient care. However, there are notable challenges in optimizing how residents are trained in cosmetic and laser dermatology. To address these barriers and elevate the practice of cosmetic dermatology in academic medicine, the Association of Academic Cosmetic Dermatology (AACD) was founded in 2021 as the lead professional society for dermatologists who direct the education of resident trainees in cosmetic and laser dermatology. The AACD,a group of board-certified dermatologists who teach cosmetic and laser dermatology to residents, aims to improve cosmetic dermatology education through collaboration, research, and advocacy.