Ablative Laser Research Articles

Treatment of hypopigmented burn hypertrophic scars with short-term topical tacrolimus does not lead to repigmentation.

Dyschromia is an understudied aspect of hypertrophic scar (HTS). The use of topical tacrolimus has successfully shown repigmentation in vitiligo patients through promotion of melanogenesis and melanocyte proliferation. It was hypothesized that HTSs treated with topical tacrolimus would have increased repigmentation compared to controls. Full-thickness burns in red Duroc pigs were either treated with excision and meshed split-thickness skin grafting or excision and no grafting, and these wounds formed hypopigmented HTSs (n = 8). Half of the scars had 0.1% tacrolimus ointment applied to the scar twice a day for 21 days, while controls had no treatment. Further, each scar was bisected with half incurring fractional ablative CO2 laser treatment before topical tacrolimus application to induce laser-assisted drug delivery (LADD). Pigmentation was evaluated using a noninvasive probe to measure melanin index (MI) at Days 0 (pretreatment), 7, 14, and 21. At each timepoint, punch biopsies were obtained and fixed in formalin or were incubated in dispase. The formalin-fixed biopsies were used to evaluate melanin levels by H&E staining. The biopsies incubated in dispase were used to obtain epidermal sheets. The ESs were then flash frozen and RNA was isolated from them and used in quantitative reverse transcription polymerase chain reaction for melanogenesis-related genes: Tyrosinase (TYR), TYR-related protein-1 (TYRP1), and dopachrome tautomerase (DCT). Analysis of variance test with Šídák's multiple comparisons test was used to compare groups. Over time, within the grafted HTS and the NS group, there were no significant changes in MI, except for Week 3 in the -Tacro group. (+Tacro HTS= pre = 685.1 ± 42.0, w1 = 741.0 ± 54.16, w2 = 750.8 ± 59.0, w3 = 760.9 ± 49.8) (-Tacro HTS= pre = 700.4 ± 54.3, w1 = 722.3 ± 50.7, w2 = 739.6 ± 53.2, w3 = 722.7 ± 50.5). Over time, within the ungrafted HTS and the NS group, there were no significant changes in MI. (+Tacro HTS= pre = 644.9 ± 6.9, w1 = 661.6 ± 3.3, w2 = 650.3 ± 6.2, w3 = 636.3 ± 7.4) (-Tacro HTS= pre = 696.8 ± 8.0, w1 = 695.8 ± 12.3, w2 = 678.9 ± 14.0, w3 = 731.2 ± 50.3). LADD did not lead to any differential change in pigmentation compared to the non-LADD group. There was no evidence of increased melanogenesis within the tissue punch biopsies at any timepoint. There were no changes in TYR, TYRP1, or DCT gene expression after treatment. Hypopigmented HTSs treated with 0.1% tacrolimus ointment with or without LADD did not show significantly increased repigmentation. This study was limited by a shorter treatment interval than what is known to be required in vitiligo patients for repigmentation. The use of noninvasive, topical treatments to promote repigmentation are an appealing strategy to relieve morbidity associated with dyschromic burn scars and requires further investigation.

Filament coating system assists recovery of ablative fCO2 laser treatment: A split-face clinical observation.

The current nursing procedure after fractional carbon dioxide (fCO2) is complex and needs to be optimized. The present study was conducted to evaluate the assisting effect of filament coating system after fCO2 laser treatment. Chinese individuals aged from 18 to 65 years diagnosed as photoaging or atrophic acne scar were recruited and each participant was treated with one single pass of fCO2 laser. A split face was randomly assigned as treatment side or control side. For control side, conventional procedure was topically applied respectively, including desonide cream two times for 3 days, fusidic acid cream two times for 7 days, and recombinant human epidermal growth factor (RhEGF) gel four times for 7 days; for treating side, a filament coating system was applied immediately after one application of fusidic acid cream, desonide cream and RhEGF, and removed 3 h later, for 3 days. Erythema, edema, crust, and pain on both sides were scored from 0 to 10 before and 1, 2, 4, and 7 days after fCO2 laser treatment. Stratum corneum hydration (SCH) and sebum of forehead and cheek on both sides were also measured by using Corneometer-Sebumeter. Twenty photoaging and 11 atrophic acne scar participants finished the observation. All of them complained of erythema, edema, crust, and pain after fCO2 laser treatment, and the scores decreased as time passed by. There were no statistical significances of erythema, edema, crust, pain, SCH, and sebum between treating side and control side at each observation time. Filament coating system was effective, safe, convenient, and economic in assisting recovery of ablative fCO2 laser, which might be a new option for additional nursing procedure.

COMPARATIVE CHARACTERISTICS OF SKIN RECOVERY IN RATS AFTER ULTRAVIOLET IRRADIATION WITH AND WITHOUT ERBIUM LASER

Introduction. Ultraviolet radiation, which has a significant biological impact among the spectrum of sunlight, can cause skin aging and tumors, but in controlled use it also has therapeutic effects on the skin. Ultraviolet radiation with a wavelength of 311 nm is used for phototherapy of skin diseases. Melanin, contained in melanosomes (MS), is produced in melanocytes (MC) during melanogenesis. Phototherapy can cause clinical hyperpigmentation by provoking an increase in the number of MCs. Ablative lasers, such as Er:YAG, are used to manage hyperpigmentation, but at the same time have the risk of causing hyperpigmentation. The frequency of such side effects varies from 10 to 46%. The aim of the study was to determine changes in the number of MCs in the epidermis relative to the length of the basement membrane and the density of MSs in the epidermis in two groups of animals: after UV irradiation without and with an ablative laser. Materials and methods. The study began with an imitation of phototherapy of dermatoses with narrow-band UV radiation. The animals were divided into 2 experimental groups: free readaptation, using laser and a separate control group (intact rats). Skin samples were taken from 54 rats: 12 animals per checkpoint (6 for each group) on days 31, 45, 61, and 121, and 6 animals in the control group. The melanocytic and melanosomal components of the epidermis were evaluated, and comparisons were made between groups and with intact animals. Results. In the group of free readaptation on day 45, the density of MCs reached 0.78±0.16 cells per 100 mkm of basal membrane (units), which exceeded the normal value, but did not show statistical significance (p=0.37). On days 61 and 121, the density was 0.72±0.13 units and 0.70±0.17 units, respectively, which indicated a correlation with the elapsed time, r = -0.732, but at once was not significantly different from the control group. In the laser hypopigmentation group, the density of MCs on the basement membrane was 0.68±0.26, 0.70±0.26 and 0.69±0.23 units on days 45, 61 and 121, respectively, demonstrating stability. The correlation between MCs density and time after UV irradiation was not taken into account (r = ‑0.485). As for the analysis of MSs, in the control group, the area of MSs was 0.77±0.24% of the epidermis square. On day 31, the density of MSs reached a peak and amounted to 1.21±0.32%, statistically different from the control group (p=0.04). Subsequently, in the group of free readaptation, the area of MSs decreased to 1.03±0.16% on day 45, 0.91±0.13% on day 61, and 0.91±0.25% on day 121. An inverse correlation was observed between the density of MSs and the elapsed time, r = -0.735. Similar patterns were observed in the laser ablation group. On days 45, 61, and 121, the area of MSs was 1.07±0.28%, 0.92±0.22%, and 0.84±0.19%, respectively. The correlation between MSs density and time after UV irradiation was significant, r = -0.881. Comparison of the density of MSs in the epidermis between the experimental groups did not reveal statistical differences at any stage of the experiment. Conclusions. The described ultraviolet impact on the skin did not lead to a statistically significant increase in the number of MCs on the basal membrane (p=0.37), but significantly increased the area of MSs in the epidermis (p=0.04). Comparison of the density of MCs in the groups of laser hypopigmentation and free readaptation did not reveal statistically significant differences between each other and the control group. Laser ablation did not lead to either an increase or decrease in the average concentration of MSs in the epidermis compared to the free readaptation group.

The effect of fractional microablative carbon dioxide laser therapy on vaginal atrophy in menopause women: A review

Vaginal atrophy is one of Genitourinary Syndrome of menopause. This condition occurs due to decreased estrogen levels during menopause. Epidemiological data obtained from several countries estimated that up to 50% of post-menopausal women experience symptoms of vaginal atrophy. This paper aims to conduct a systematic review, and this meta-analysis is to analyze the effect of micro ablative fractional CO2 laser therapy on vaginal atrophy in postmenopausal women. Data was collected online from Pubmed-MEDLINE, Scopus, EBSCO, Cambridge Core, ProQuest, Springer Link, Cochrane Library, and ClinicalTrials.gov databases. Tracking will be carried out in May-July 2023. The population of this study is the result of clinical trial research on the effect of microablative fractional CO2 laser therapy on vaginal atrophy in postmenopausal women. Meta-analysis showed that the VHI score was higher after therapy in the group that received micro ablative fractional CO2 laser compared to the group that received sham laser for vaginal atrophy in menopausal women. VAS scores were lower after administration in the group that received microablative fractional CO2 laser compared to the group that received sham laser for vaginal atrophy in menopausal women. The incidence of side effects in the CO2 laser group did not differ from the sham laser group. This study recommends an RCT study was conducted comparing micro ablative fractional CO2 laser compared to other energy-based devices such as erbium laser and radiofrequency on vaginal atrophy in postmenopausal women so that it can be used as a basis for further systematic review research and meta-analysis.

Influence of scar age, laser type and laser treatment intervals on paediatric burn scars: a systematic review and meta-analysis.

Laser therapy has emerged to play a valuable role in the treatment of paediatric burn scars; however, there is heterogeneity in the literature, particularly concerning optimal timing for initiation of laser therapy. This study aims to investigate the effect of factors such as scar age, type of laser and laser treatment interval on burn scar outcomes in children by meta-analysis of previous studies. A literature search was conducted across seven databases in May 2022 to understand the effects of laser therapy on burn scar outcomes in paediatric patients by metanalysis of standardized mean difference (SMD) between pre- and post-laser intervention. Meta-analyses were performed using the Comprehensive Meta-Analysis software version 4.0. Fixed models were selected when there was no significant heterogeneity, and the random effects model was selected for analysis when significant heterogeneity was identified. For all analyses, a p-value < 0.05 was considered significant. Seven studies were included in the meta-analysis with a total of 467 patients. Laser therapy significantly improved Vancouver Scar Scale (VSS)/Total Patient and Observer Scar Assessment Scale (Total POSAS), vascularity, pliability, pigmentation and scar height of burn scars. Significant heterogeneity was found between the studies and thus subgroup analyses were performed. Early laser therapy (<12months post-injury) significantly improved VSS/POSAS scores compared to latent therapy (>12months post-injury) {SMD -1.97 [95% confidence interval (CI) = -3.08; -0.87], p < 0.001 vs -0.59 [95%CI = -1.10; -0.07], p = 0.03} as well as vascularity {SMD -3.95 [95%CI = -4.38; -3.53], p < 0.001 vs -0.48 [95%CI = -0.66; -0.30], p < 0.001}. Non-ablative laser was most effective, significantly reducing VSS/POSAS, vascularity, pliability and scar height outcomes compared to ablative, pulse dye laser and a combination of ablative and pulse dye laser. Shorter treatment intervals of <4 weeks significantly reduced VSS/POSAS and scar height outcomes compared to intervals of 4 to 6 weeks. Efficacy of laser therapy in the paediatric population is influenced by scar age, type of laser and interval between laser therapy application. The result of this study particularly challenges the currently accepted initiation time for laser treatment. Significant heterogeneity was observed within the studies, which suggests the need to explore other confounding factors influencing burn scar outcomes after laser therapy.

Enhanced Scaling of Material Removal Rate with High Surface Quality Through Combined Laser Processes

In the field of ultrashort pulse laser processing, the effective utilization of average power provided by todays laser systems presents an almost unsolvable challenge. This study aims to address this challenge in the context of laser volume ablation. We propose a solution for utilization of high average power while producing a high-quality finish, even when starting from arbitrary surfaces. The approach combines closed loop laser volume ablation, laser cleaning and laser polishing in a subsequent process strategy. The closed loop approach enables ablative laser processes to be used to produce precise target geometries and surfaces, even if the initial geometry of the component is very different from the target geometry. One application example is the post-processing of components manufactured using additive processes such as laser powder bed fusion. Therefore, we demonstrate automated removal of support structures and finishing of a sample made of AlSi10Mg material by laser powder bed fusion. The combination of laser ablation and laser polishing made it possible to significantly increase the productivity of the post-processing and achieving a surface roughness of Ra = 0.3 µm.

Adverse effects associated with ablative lasers when treating common dermatologic conditions: a systematic review of 946 patients

CO2 and Er:YAG are the two most common types of ablative lasers in use today. Ablative lasers are known for their superior efficacy in penetrating deeper through the skin layers when compared to non-ablative lasers. This review compares the outcomes and adverse events associated with CO2 and Er: YAG lasers, in conjunction with other therapeutic modalities, in the treatment of common skin conditions. A PRISMA-compliant systematic review of PubMed and Embase databases was conducted from January 2012 to December 2022. Study types that were eligible for this review included clinical trials, randomized controlled trials, case reports, case series, cohort studies, and meta-analyses. The study protocol was registered (PROSPERO 2022: CRD42022348569). The search strategy produced 27 studies comprising 946 patients who were treated for acne scars, postacne hyperpigmentation, solar lentigines, facial rejuvenation, refractory vitiligo, and epidermal verrucous nevi. Erythema, pain, and hyperpigmentation were the most commonly reported adverse effects. A higher rate of adverse events was observed in CO2 laser therapies (n=610, 64.5%) when compared to Er: YAG and other laser cohorts (n=40, 4.2%). Both CO2 and Er: YAG lasers demonstrate similar efficacy in the treatment of benign cutaneous conditions. Further research is needed for parallel comparison of CO2 and Er: YAG lasers.

Efficacy of erbium yttrium aluminium garnet laser on post-traumatic scars among Indian population – A non-randomized study

Objectives: The post-trauma scar is a common problem; it can produce physical and psychological difficulties to the patient. The use of ablative and non-ablative lasers based on the fractional approach is emerging as a method to treat scars. However, very limited data are available of the same in patients of South India. In this study, the authors demonstrated the efficacy of ablative fractional resurfacing (AFR) for traumatic scars using a 2940-nm erbium: yttrium-aluminum-garnet (Er: YAG) laser for the treatment of post-traumatic scars in patients of south India. Material and Methods: Seventy-three scars were enrolled in adults of age between 18 and 60 years. Each scar was treated four times at 1-month intervals with a fractional ablative 2940-nm Er: YAG laser using the same parameters. Pre-treatment evaluation before the initiation of the treatment and post-treatment evaluation was performed 1 month after the fourth treatment session of laser. The scar was evaluated using Vancouver scar scale (VSS). Results: All 73 scars completed the study. After ablative fractional laser treatment, all treated portions of the scars showed improvements, as demonstrated by the VSS. Conclusion: This study shows that ablative fractional application of Er: YAG laser treatment of scars reduces scars fairly. The authors suggest that treatment using AFR can be a adjuvant scar management method for improving the quality of life of patients with post-traumatic scars in patients of south India.

Treatment of hypertrophic scars with ablative fractional carbon dioxide laser assisted with different topical triamcinolone delivery ways

ObjectivesAblative fractional carbon dioxide laser has been used with triamcinolone to treat hypertrophic scars, resulting in promising success rates. However, there are different topical triamcinolone delivery methods used in scar treatment. To assess the efficacy among the different triamcinolone delivery methods, this study was designed to compare the efficacy and safety of ablative fractional carbon dioxide laser followed by penetration and injection of topical triamcinolone into thicker hypertrophic scars (height score of VSS ≥2). Study design/materials and methodsWe performed a retrospective study of 155 thicker hypertrophic scar patients (height score of VSS ≥2), including 88 patients in the triamcinolone external application group and 67 patients in the triamcinolone intralesional injection group. One month after the patients had 3 treatment sessions at 4-week intervals, the scars were assessed by photography, the Vancouver Scar Scale (VSS), durometry and spectrocolorimetry. Any adverse effects were also evaluated. ResultsThe VSS scores and the hardness of the scars in both groups improved significantly compared to baseline. Moreover, the patients in the triamcinolone intralesional injection group had higher treatment efficacy (19.77 ± 21.25 %) based on their VSS scores than the patients in the triamcinolone external application group (5.94 ± 24.07 %), especially in the improvement of scar pliability, height and hardness. Meanwhile, in the triamcinolone injection group, more patients had mild and moderate improvement than in the triamcinolone application group. However, there were no differences in the distribution of the adverse effects in either group. ConclusionsThis study demonstrated that using the ablative fractional carbon dioxide laser followed by different topical triamcinolone delivery methods is effective and safe for thicker hypertrophic scar improvement. The method of using the ablative fractional carbon dioxide laser assisted with triamcinolone injection had a better therapeutic outcome in thicker hypertrophic scars, as compared with triamcinolone penetration.

Impact of skin hydration on patterns of microthermal injury produced by fractional CO2 laser.

The impact of skin hydration on patterns of thermal injury produced by ablative fractional lasers (AFLs) is insufficiently examined under standardized conditions. Using skin with three different hydration levels, this study assessed the effect of hydration status on microchannel dimensions generated by a fractional CO2 laser. A hydration model (hyperhydrated-, dehydrated- and control) was established in ex vivo porcine skin, validated by changes in surface conductance and sample mass. After, samples underwent AFL exposure using a CO2 laser (10,600 nm) at two examined pulse energies (10 and 30 mJ/mb, fixed 10% density, six repetitions per group). Histological assessment of distinct microchannels (n = 60) determined three standardized endpoints in H&E sections: (1) depth of microthermal treatment zones (MTZs),(2) depth of microscopic ablation zones (MAZs), and (3) coagulation zone (CZ) thickness. As a supplemental in vivo assessment, the same laser settings were applied to hyperhydrated- (7-h occlusion) and normohydrated forearm skin (no pretreatment) of a human volunteer. Blinded measurement of MAZ depth (n = 30) was performed using noninvasive optical coherence tomography (OCT). Modest differences in microchannel dimensions were shown between hyperhydrated, dehydrated and control skin at both high and low pulse energy. Compared to controls, hyperhydration led to median reductions in MTZ and MAZ depth ranging from 5% to 8% (control vs. hyperhydrated at 30 mJ/mb; 848 vs. 797 µm (p < 0.003) (MAZ); 928 vs. 856 µm (p < 0.003) (MTZ)), while 14%-16% reductions were shown in dehydrated skin (control vs. dehydrated at 30 mJ/mb; MAZ: 848 vs. 727 µm (p < 0.003); MTZ: 928 vs. 782 µm (p < 0.003)). The impact of skin hydration on CZ thickness was in contrast limited. Corresponding with ex vivo findings, hyperhydration was similarly associated with lower ablative depth in vivo skin. Thus, median MAZ depth in hydrated skin was 10% and 14% lower than in control areas at 10 and 30 mJ/mb pulse energy, respectively (10 mJ: 210 vs. 180 µm (p < 0.001); 30 mJ: 335 vs. 300 µm (p < 0.001)). Skin hydration status can exert a minimal impact on patterns of microthermal injury produced by fractional CO2 lasers, although the clinical implication in the context of laser therapy requires further study.

Striae distensae treatment: evaluating laser efficacy and safety.

Striae distensae (SD) are common skin lesions that are difficult to treat and affect quality of life. Laser and light are emerging non-invasive therapies that have proven successful in treating SD. Recently, hybrid laser devices offering simultaneous fractional ablative and non-ablative laser treatment have been reported to benefit various skin conditions. To evaluate the improvement of SD treated with a hybrid laser system and to analyze associations with patient characteristics. We performed a retrospective study in which 28 adults with SD were treated with a hybrid laser device. Efficacy was evaluated by the assessment of aesthetic improvement by the Global Aesthetic Improvement Scale (GAIS) of 1-10 and by patients' satisfaction using a scale of 0-10 satisfaction scale. Pain and adverse events were monitored. Statistical analysis was used to examine the potential impact of various factors on treatment outcomes. The mean GAIS score was 7.36 ± 1.06 with a positive correlation with patient satisfaction (r = 0.685) and a weak negative correlation with patient age (r = -0.0057). Skin type and body area did not show significant associations with GAIS scores (P > 0.05 for both). No adverse events were observed. This study demonstrates the potential of the hybrid laser system as a safe and effective method to achieve satisfactory aesthetic results with minimal downtime, making it a promising treatment approach for SD. Treatment outcomes were independent of patient characteristics, further supporting its widespread use.

New comprehensive method for treatment of atrophic skin scars

Striae distensae, commonly known as stretch marks, are visible linear atrophic scars. Despite quite numerous studies, the lack of a unified approachto the problem of treating atrophic scars, a detailed clinical and morphological classification leads to the fact that doctors empirically choosepatient management tactics, which leads to unreliability or even lack of effect, the need for numerous repeated courses of therapy, and significanteconomic costs. The article presents data on studying the effectiveness of various methods of therapy. Depending on the method of therapy,patients were divided into three groups by simple randomization. The study used a visual analogue scale (VAS) to assess the clinical symptomsof AR. The combined use of fractional ablative laser and PDT with the topical photosensitizer chlorin e6 is highly effective in the treatment ofatrophic scars lasting more than a year (VAS dynamics – 74.9 %), fractional ablative laser is moderately effective in long-term atrophic scars (VASdynamics – 65.6 %), while PDT in the form of monotherapy is insufficiently effective (VAS dynamics – 45.6 %).

Multimodal feedback systems for smart laser osteotomy: Depth control and tissue differentiation.

The study aimed to improve the safety and accuracy of laser osteotomy (bone surgery) by integrating optical feedback systems with an Er:YAG laser. Optical feedback consists of a real-time visual feedback system that monitors and controls the depth of laser-induced cuts and a tissue sensor differentiating tissue types based on their chemical composition. The developed multimodal feedback systems demonstrated the potential to enhance the safety and accuracy of laser surgery. The proposed method utilizes a laser-induced breakdown spectroscopy (LIBS) system and long-range Bessel-like beam optical coherence tomography (OCT) for tissue-specific laser surgery. The LIBS system detects tissue types by analyzing the plasma generated on the tissue by a nanosecond Nd:YAG laser, while OCT provides real-time monitoring and control of the laser-induced cut depth. The OCT system operates at a wavelength of 1288 ± 30 nm and has an A-scan rate of 104.17 kHz, enabling accurate depth control. Optical shutters are used to facilitate the integration of these multimodal feedback systems. The proposed system was tested on five specimens of pig femur bone to evaluate its functionality. Tissue differentiation and visual depth feedback were used to achieve high precision both on the surface and in-depth. The results showed successful real-time tissue differentiation and visualization without any visible thermal damage or carbonization. The accuracy of the tissue differentiation was evaluated, with a mean absolute error of 330.4 μm and a standard deviation of ±248.9 μm, indicating that bone ablation was typically stopped before reaching the bone marrow. The depth control of the laser cut had a mean accuracy of 65.9 μm with a standard deviation of ±45 μm, demonstrating the system's ability to achieve the pre-planned cutting depth. The integrated approach of combining an ablative laser, visual feedback (OCT), and tissue sensor (LIBS) has significant potential for enhancing minimally invasive surgery and warrants further investigation and development.

Biological effect of laser-assisted scar healing (LASH) on standardized human three-dimensional wound healing skin models using fractional non-ablative 1540 nm Er:Glass or 1550 nm diode lasers.

In postoperative wound healing after surgical operations or ablative laser treatments, recent studies suggest the timely use of non-ablative fractional laser treatments with the aim to improve wound healing and prevent pathological scar formation. However, the underlying molecular mechanisms are poorly understood. The aim of this study was to investigate the effects of laser-assisted scar healing (LASH) at the molecular level and to combine it with already established wound healing-promoting local treatments. We irradiated full-thickness 3D skin models with a fractional ablative Er:YAG laser to set standardized lesions to the epidermal and upper dermal layer. Subsequently, LASH was induced by irradiating the models with either a fractional non-ablative 1540 nm Er:Glass or 1550 nm diode laser. In addition, we tested the combination of non-ablative fractional laser treatment and topical aftercare with a dexpanthenol-containing ointment (DCO). Histological analysis revealed that models irradiated with the 1540 nm Er:Glass or 1550 nm diode laser exhibited accelerated but not complete wound closure after 16 h. In contrast, additional topical posttreatment with DCO resulted in complete wound closure. At gene expression level, both non-ablative laser systems showed similar effects on epidermal differentiation and mild anti-inflammatory properties. The additional posttreatment with DCO enhanced the wound-healing effects of LASH, especially the upregulation of epidermal differentiation markers and anti-inflammatory cytokines at the gene expression level. This in vitro study deciphers the biological effects of LASH with a fractional non-ablative 1540 nm Er:Glass or a 1550 nm diode laser in 3D skin models. These data help to better understand the biological properties of the LASH technique and is important to optimize its application.

In vivo characterization of laser-assisted delivery of hyaluronic acid using multiphoton fluorescence lifetime imaging.

Laser-assisted drug delivery (LADD) is a treatment method to enhance the penetration of pharmaceuticals through the skin. The aim of the present study is to track hyaluronic acid (HA) and analyse its effect on human skin invivo after ablative fractional laser (AFL) treatment. Healthy male and female subjects were recruited. Four areas were marked on their forearms of each volunteer, and each area was assigned to one of the following treatment options: AFL + HA, AFL only, HA only or untreated control. A carbon dioxide laser was used for the AFL treatment. Follow-up measurements were scheduled 30 min and 30 days after treatment using multiphoton tomography equipped with fluorescence lifetime imaging (MPT-FLIM). A total of 11 subjects completed the study. By detecting fluorescence lifetimes, the HA and the anaesthetic ointment were clearly distinguishable from surrounding tissue. After AFL treatment, HA could be visualized in all epidermal and upper dermal layers. In contrast, HA in intact skin was only detected in the superficial layers at distinctly lower levels. The applied HA gel seemed to have beneficial properties for the wound healing process after laser treatment. LADD has proven to be a fast and effective method to increase HA uptake into the skin, allowing for improved hydration and skin rejuvenation over time. Furthermore, LADD could be a beneficial treatment option in laser resurfacing. MPT-FLIM proved to be an appropriate diagnostic tool for drug delivery tracking and monitoring of treatment response for individualized therapy adjustment.

Efficacy of low energy fractional carbon dioxide laser therapy in management of post-surgical hypertrophic scars

Background: aberrant &amp; accelerated wound-healing process that results in hypertrophic scarring causes extracellular matrix &amp; collagen to deposit abnormally in the dermis. After tissue damage occurs, a defensive reaction called tissue repair occurs. Aim; in this review; we aimed to present the effectiveness of low-energy fractional carbon dioxide laser therapy in treating hypertrophic scars following surgery. Summary: A safe &amp; effective approach for treating hypertrophic burn scars is fractional ablative CO2 laser therapy. Even though more treatment sessions have been necessary for satisfying outcomes, a big improvement can be seen after just one round of therapy. Combination therapy with other modalities can decrease the need for repetition of therapy as efficacy increases. Though, in some studies, combination therapy may shorten the duration of studied case downtime &amp; in others, combination therapy may increase side effects. essential for laser energy setting needs to be adjusted for each hypertrophic scar condition. larger research population &amp; longer follow-up period are recommended.

Clinical and dermoscopic assessment of ablative carbon dioxide laser versus intradermal heparin sodium in xanthelasma.

Ablative carbon dioxide (CO2 ) laser is still a cornerstone in the management of xanthelasma. However, post-laser complications such as post-inflammatory hyperpigmentation or scarring have to be considered. Heparin sodium was recently suggested as an effective therapeutic modality for xanthelasma. The aim of this work was to compare the therapeutic value of ablative CO2 laser versus intradermal heparin sodium in xanthelasma. This study was piloted on 30 xanthelasma patients, whose lesions were randomly categorized into two groups. Group A was managed with CO2 laser ablation (2 sessions scheduled every 4 weeks), whereas Group B was managed with intradermal heparin sodium injections (10 sessions scheduled every week). Pre- and post-treatments evaluations were done both clinically and dermoscopically. Significant reduction of xanthelasma lesions was reported in response to both therapeutic interventions. However, the ablative CO2 laser was more significantly effective than intradermal heparin sodium. Interestingly, intradermal injection of heparin sodium was nearly as effective as ablative CO2 laser in early (<2 years duration) grade I and II xanthelasma, with a lower incidence of post-therapy side effects. Intradermal injection of heparin sodium could be suggested as a safe and cost-effective therapeutic technique for early mild grade I and II xanthelasma. Moreover, it could be recommended as a pre-operative management of grade III and IV xanthelasma to reduce the lesions to be easily ablated with CO2 laser.

Vaginal treatment with solid state non ablative laser 1470 nm for vaginal atrophy in post menopausal women

One of the most common menopausal symptoms is vaginal dryness. Menopausal sex hormone deficiency causes changes in the urogenital tract, where estrogens are the primary regulators of vaginal physiological functions. Many treatments have been developed over the years, but the majority of them are ineffective or have potential side effects. Actually, laser therapy has the highest efficacy with the fewest (or none) side effects. Thermal energy acting on the vaginal wall has been shown in studies to stimulate collagen synthesis, induce neovascularization, enrich the glycogen epithelium, improve vaginal lubrication, and treat urinary incontinence. However, not all lasers are created equal. The majority of published studies describe the data from CO2 laser therapy, Erbium laser therapy, and radiofrequency. Less is known about the new 1470 nm solid state laser. This is a retrospective study in which 16 women with vaginal dryness were treated with a 1470 nm solid state vaginal laser. All of the patients were cured of vaginal dryness with no pain, bleeding, scarring, or other side effects.

Influence of scar age, laser type and laser treatment intervals on adult burn scars: A systematic review and meta-analysis.

The study aims to identify whether factors such as time to initiation of laser therapy following scar formation, type of laser used, laser treatment interval and presence of complications influence burn scar outcomes in adults, by meta-analysis of previous studies. A literature search was conducted in May 2022 in seven databases to select studies on the effects of laser therapy in adult hypertrophic burn scars. The study protocol was registered with PROSPERO (CRD42022347836). Eleven studies were included in the meta-analysis, with a total of 491 patients. Laser therapy significantly improved overall VSS/POSAS, vascularity, pliability, pigmentation and scar height of burn scars. Vascularity improvement was greater when laser therapy was performed >12 months (-1.50 [95%CI = -2.58;-0.42], p = 0.01) compared to <12 months after injury (-0.39 [95%CI = -0.68; -0.10], p = 0.01), the same was true for scar height ((-1.36 [95%CI = -2.07; -0.66], p<0.001) vs (-0.56 [95%CI = -0.70; -0.42], p<0.001)). Pulse dye laser (-4.35 [95%CI = -6.83; -1.86], p<0.001) gave a greater reduction in VSS/POSAS scores compared to non-ablative (-1.52 [95%CI = -2.24; -0.83], p<0.001) and ablative lasers (-0.95 [95%CI = -1.31; -0.59], p<0.001). Efficacy of laser therapy is influenced by the time lapse after injury, the type of laser used and the interval between laser treatments. Significant heterogeneity was observed among studies, suggesting the need to explore other factors that may affect scar outcomes.

Towards phase-sensitive optical coherence tomography in smart laser osteotomy: temperature feedback

Thermal effects during bone surgery pose a common challenge, whether using mechanical tools or lasers. An irrigation system is a standard solution to cool the tissue and reduce collateral thermal damage. In bone surgery using Er:YAG laser, insufficient irrigation raises the risk of thermal damage, while excessive water lowers ablation efficiency. This study investigated the potential of optical coherence tomography to provide feedback by relating the temperature rise with the photo-thermal expansion of the tissue. A phase-sensitive optical coherence tomography system (central wavelength of λ=1.288 μm, a bandwidth of 60.9 nm and a sweep rate of 104.17 kHz) was integrated with an Er:YAG laser using a custom-made dichromatic mirror. Phase calibration was performed by monitoring the temperature changes (thermal camera) and corresponding cumulative phase changes using the phase-sensitive optical coherence tomography system during laser ablation. In this experiment, we used an Er:YAG laser with 230 mJ per pulse at 10 Hz for ablation. Calibration coefficients were determined by fitting the temperature values to phase later and used to predict the temperature rise for subsequent laser ablations. Following the phase calibration step, we used the acquired values to predict the temperature rise of three different laser-induced cuts with the same parameters of the ablative laser. The average root-mean-square error for the three experiments was measured to be around 4 °C. In addition to single-point prediction, we evaluated this method’s performance to predict the tissue’s two-dimensional temperature rise during laser osteotomy. The findings suggest that the proposed principle could be used in the future to provide temperature feedback for minimally invasive laser osteotomy.