Review of Lasers and Energy-Based Devices for Skin Rejuvenation and Scar Treatment With Histologic Correlations

Histological Assessment of the Effectiveness of Microneedling Device-Assisted Filler Delivery

BACKGROUND

Microneedling is used to enhance transcutaneous drug delivery. However, the extent to which microneedling devices impact filler delivery and whether this varies by filler type, microneedling device type, and treatment sequence is not known.

OBJECTIVE

To histologically assess and quantify the delivery of commonly used fillers through microneedling, using both a microneedling pen and a microneedling roller. In addition, the authors investigated whether there is a variation in filler delivery based on the sequence of microneedling in relation to topical filler application.

METHODS

Ex vivo human abdominal skin samples were subjected to microneedling pen or microneedling roller treatment. Black tissue marking ink, hyaluronic acid, poly-l-lactic acid, or undiluted calcium hydroxyapatite was topically applied before or immediately after microneedling treatment.

RESULTS

Histological evaluation revealed a notable presence of black ink within channels formed by both microneedling treatments (15.5%-98.1%), whereas there was limited presence of the various filler types tested (0%-6.6%) in all settings. Topical application before microneedling treatment led to relatively higher filler/ink deposition within the channels formed by the microneedling treatments compared with topical application after microneedling.

CONCLUSION

Transcutaneous delivery of fillers was not significantly helped by microneedling treatment, whereas the microneedling devices demonstrated effective delivery of an aqueous solution.

Deep learning automatically assesses 2-µm laser-induced skin damage OCT images

The present study proposed a noninvasive, automated, in vivo assessment method based on optical coherence tomography (OCT) and deep learning techniques to qualitatively and quantitatively analyze the biological effects of 2-µm laser-induced skin damage at different irradiation doses. Different doses of 2-µm laser irradiation established a mouse skin damage model, after which the skin-damaged tissues were imaged non-invasively in vivo using OCT. The acquired images were preprocessed to construct the dataset required for deep learning. The deep learning models used were U-Net, DeepLabV3+, PSP-Net, and HR-Net, and the trained models were used to segment the damage images and further quantify the damage volume of mouse skin under different irradiation doses. The comparison of the qualitative and quantitative results of the four network models showed that HR-Net had the best performance, the highest agreement between the segmentation results and real values, and the smallest error in the quantitative assessment of the damage volume. Based on HR-Net to segment the damage image and quantify the damage volume, the irradiation doses 5.41, 9.55, 13.05, 20.85, 32.71, 52.92, 76.71, and 97.24 J/cm² corresponded to a damage volume of 4.58, 12.56, 16.74, 20.88, 24.52, 30.75, 34.13, and 37.32 mm³. The damage volume increased in a radiation dose-dependent manner.

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.

Combined microfocused ultrasound and delicate pulsed light for facial rejuvenation: A prospective, randomized, and split-face study

OBJECTIVES

Public's interest in noninvasive skin rejuvenation treatments continues to grow. The advantage of combination therapy lies in that it can target different aspects of skin rejuvenation. This study aimed to assess the efficacy and safety of microfocused ultrasound (MFU) combined with delicate pulsed light (DPL) for facial rejuvenation.

METHODS

Twenty-one patients with facial relaxation were enrolled. All patients received whole-face MFU treatment, and one side of the face was randomly assigned to receive DPL. MFU treatment was performed at Months 0 and 3, while DPL treatment was performed at Months 1, 2, 4, and 5. The length and angle of the nasolabial fold and perioral wrinkles, melanin index (MI), erythema index (EI), transepidermal water loss (TEWL), and follow-up time were recorded at Months 0, 3, and 6. Side effects were recorded during treatment and each follow-up visit.

RESULTS

Twenty patients successfully completed the study. At the sixth month, the average length of perioral wrinkles and nasolabial folds on the combined side decreased by 11.5% (pwithin < 0.001) and 6.5% (pwithin = 0.011), while 8.3% (pwithin = 0.012) and 3.8% (pwithin = 0.02) on the MFU side. Compared with MFU treatment alone, the combined treatment also showed significant improvements in nasolabial fold angle (from 28.8 ± 3.4° to 32.7 ± 5.0°) and perioral wrinkle angle (from 39.3 ± 5.0° to 43.7 ± 5.1°). In addition, the combined side had greater benefits than the MFU side in improving MI, EI, TEWL, and skin elasticity (pbetween < 0.05). Except for one patient who withdrew due to increased skin sensitivity after MFU treatment, other subjects did not experience permanent or serious side effects.

CONCLUSIONS

The combination of MFU and DPL for facial rejuvenation treatment is safe and effective. The combined treatment has better efficacy in skin firmness, and improving skin tone.

Keloid and Hypertrophic Scars Treatment

BACKGROUND

Hypertrophic scars are contained within the site of injury and may regress over time, while keloids spread beyond the borders of the initial injury and do not regress. On histologic examination, hypertrophic scars tend to have collagen in a wavy, regular pattern, whereas keloids have no distinct pattern of collagen.

OBJECTIVE

To retrospectively analyze improvement in keloid and hypertrophic scars characteristics following treatment with Ablative 10600 nm and a non-Ablative 1570 nm Hybrid Laser Device.

METHODS

Treatment parameters with the ProScan Hybrid Mode were 40 W/1.3-1.5 ms for the CO2 and 12 W/4 ms for the 1570 nm in a 1:1 ratio. Outcomes were assessed based on physician scar grading as measured by the Vancouver Scar Scale and patient-reported satisfaction. Excel was used for data analysis, and a p value < 0.05 was considered statistically significant. Adverse events and patient pain were also recorded.

RESULTS

A total of 31 hypertrophic scars and 30 keloid scars were treated. There was a significant reduction in Vancouver Scar Scale scores for both hypertrophic and keloid scars (62% ± 8% and 58% ± 7%; p = 2.6E-17 and p = 8.29E-26, respectively). In a scar-based comparison, a statistically significant difference was observed for all measures reflecting favorable outcomes for hypertrophic scars (VSS, p = 1.1E-05; satisfaction, p = 0.0112; pain, p = 0.00081). Only one adverse event was reported, a superficial burn treated with topical antibiotics.

CONCLUSIONS

The device was found to be safe and effective, with promising results for the treatment of hypertrophic and keloid scars.

LEVEL OF EVIDENCE II

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

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.

Targeting the dermis for melasma maintenance treatment

Melasma relapse is almost common after discontinuation of conventional treatment. Recent studies suggesting that photoaging dermis is the main pathomechanism of melasma, emphasize the dermal targeting therapy. We investigated maintenance effect of microneedling radiofrequency (RF) for melasma treatment. Subjects with melasma were administered oral tranexamic acid and triple combination cream for 2 months and a randomly assigned half face was treated with RF. After discontinuation of conventional therapy, the half face RF continued monthly over 6 months. Modified melasma area severity index (mMASI) score and L* value by a chromameter were collected monthly. Fifteen subjects were enrolled and eleven completed the 8-month study. At 2nd month of conventional therapy, all subjects showed improvement with a 64% reduction in mMASI score. With continuous RF treatment, the improvement was well maintained; whereas in untreated side, the Δ L* gradually decreased, returning to the baseline after the conventional therapy ended. The continuous microneedling RF therapy is beneficial in maintaining the conventional therapy of melasma suggesting the protective effect of dermal targeting therapy in melasma development.(Clinical Trial registration number: NCT05710068, date of first registration: 02/02/2023).

Clinically Actionable Topical Strategies for Addressing the Hallmarks of Skin Aging: A Primer for Aesthetic Medicine Practitioners

In this narrative review, we sought to provide a comprehensive overview of the mechanisms underlying cutaneous senescence, framed by the twelve traditional hallmarks of aging. These include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, impaired macroautophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation, and dysbiosis. We also examined how topical interventions targeting these hallmarks can be integrated with conventional aesthetic medicine techniques to enhance skin rejuvenation. The potential of combining targeted topical therapies against the aging hallmarks with minimally invasive procedures represents a significant advancement in aesthetic medicine, offering personalized and effective strategies to combat skin aging. The reviewed evidence paves the way for future advancements and underscores the transformative potential of integrating scientifically validated interventions targeted against aging hallmarks into traditional aesthetic practices.

Dynamic panoramic presentation of skin function after fractional CO2 laser treatment

Fractional CO2 laser, as a typical ablative laser, has been used to assist in the treatment of many skin diseases, such as photoaging, atrophic scar, hypertrophic scar, superficial pigmentation, vitiligo, and so on. However, the dynamic changes in skin function after fractional CO2 laser treatment are still unclear. This study explored the changes in local skin function and possible regulatory mechanisms after fractional CO2 laser treatment for 1, 3, 5, and 7 days through transcriptome high-throughput sequencing. The results showed that fractional CO2 laser tended to transform the "lesions" into "normal skin", regulate the skin barrier, coordinate the rearrangement of collagen, enhance the local microvascular circulation, activate the immune system to secrete a large number of cytokines, and act as an auxiliary tool to assist drug transport. In conclusion, according to the basic principle of destruction before reconstruction, fractional CO2 laser plays a key role of balancer in skin reconstruction.

Skin aging from mechanisms to interventions: focusing on dermal aging

Skin aging is a multifaceted process that involves intrinsic and extrinsic mechanisms that lead to various structural and physiological changes in the skin. Intrinsic aging is associated with programmed aging and cellular senescence, which are caused by endogenous oxidative stress and cellular damage. Extrinsic aging is the result of environmental factors, such as ultraviolet (UV) radiation and pollution, and leads to the production of reactive oxygen species, ultimately causing DNA damage and cellular dysfunction. In aged skin, senescent cells accumulate and contribute to the degradation of the extracellular matrix, which further contributes to the aging process. To combat the symptoms of aging, various topical agents and clinical procedures such as chemical peels, injectables, and energy-based devices have been developed. These procedures address different symptoms of aging, but to devise an effective anti-aging treatment protocol, it is essential to thoroughly understand the mechanisms of skin aging. This review provides an overview of the mechanisms of skin aging and their significance in the development of anti-aging treatments.

Efficacy and safety of fractional 1064-nm picosecond laser for atrophic traumatic and surgical scars: A randomized, single-blinded, split-scar-controlled study

OBJECTIVE

A fractional 1064-nm picosecond laser is an efficient and safe treatment for atrophic acne scars. However, evidence of using a picosecond laser for atrophic posttraumatic and surgical scar therapy is lacking. This study aimed to evaluate the efficacy and safety of using a 1064-nm picosecond laser with a microlens array (MLA) for the treatment of atrophic posttraumatic and surgical scars.

METHODS

This was a prospective, intraindividual, single-blinded, randomized split-lesion-controlled trial. Twenty-five subjects with atrophic traumatic or surgical scars that existed for more than 1 year were enrolled. All atrophic scars were divided at the midline into two halves and randomly assigned to a treatment or control side. The treatment group was treated with a 1064-nm picosecond laser with an MLA handpiece (spot size: 6-8 mm, fluence: 1.0-1.2 J/cm² , repetition rate: 5 Hz, three passes) for 3 monthly sessions. The scar volumes were objectively measured using a three-dimensional (3D) photograph at baseline, 1 month after the first and second treatments, and 3 and 6 months after the final treatment. Subjective assessments were conducted by a blinded dermatologist and patients' self-assessment to evaluate improvements at 3 months after the final treatment.

RESULTS

The treated sides exhibited a significant volume reduction, with statistically significant improvements over the control group at 1 month after the first and second treatments and at 3 months after the final treatment (p = 0.024, 0.005, and 0.019, respectively). At 3 months after the final treatment, a blinded dermatologist correctly identified the treated side in 24 of 25 patients (96%). The patients rated the improvements as excellent (>75%) and marked (50%-75%) in 36% and 48% of patients, respectively.

CONCLUSION

At 3 months, the 1064-nm picosecond laser with a fractionated MLA can significantly reduce the posttraumatic and postsurgical atrophic scar volume in patients with Fitzpatrick skin types III-V. Insufficient data preclude inferences regarding efficacy at 6 months.

Radiofrequency and Radiofrequency Microneedling in Skin of Color: A Review of Usage, Safety, and Efficacy

BACKGROUND

Radiofrequency (RF) and radiofrequency microneedling (RFM) for rhytides, scarring, and skin rejuvenation are believed to have a lower risk of postprocedural dyspigmentation in darker skin types.

OBJECTIVE

To explore the safety and efficacy of RF and RFM in Fitzpatrick skin Types III to VI.

METHODS AND MATERIALS

A systematic review of PubMed/MEDLINE databases from 2000 to 2021 using combinations of the terms radiofrequency, microneedling, skin of color, and Fitzpatrick was performed. Exclusion criteria included non-Fitzpatrick skin Types III-VI patient population, nonprimary articles, nonskin radiofrequency, and nonhuman studies.

RESULTS

Thirty-five articles addressing the use of RF or RFM in skin of color were identified-22 for skin rejuvenation, 7 for acne scars, 4 for nonacne scars, 1 for hyperpigmentation, and 1 for acne treatment. Seven studies noted transient postinflammatory hyperpigmentation, 1 observed mild prolonged hyperpigmentation, and only 1 study reported permanent scarring.

CONCLUSION

Radiofrequency and RFM seem to have a low risk of scarring or hyperpigmentation in skin of color. This review demonstrates that these procedures have been successfully used primarily for rhytides, acne scarring, and skin rejuvenation. However, a large proportion of the studies lack strong quality evidence.

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

Picosecond lasers have a very short pulse duration and a high peak power density. When fractional optical delivery systems are attached to picosecond lasers, they generate an array of concentrated microspots with a high fluence surrounded by areas with a low fluence. This article discusses the histologic characteristics and clinical applications of fractional picosecond laser treatment. Fractional picosecond laser produces laser-induced optical breakdown (LIOB) and laser-induced cavitation (LIC) in the epidermis and dermis respectively, and can encourage skin regeneration and dermal remodeling. It has been shown that fractional picosecond laser has a positive effect on facial photoaging, enlarged facial pores, dyspigmentation, wrinkles, and atrophic scars. Further research is still needed to confirm the benefits of fractional picosecond lasers.