Histologic comparison of microscopic treatment zones induced by fractional lasers and radiofrequency

Microplasma radio frequency technology using stationary tips on pig skin: A histological study

OBJECTIVE

To investigate the histological properties of microplasma radiofrequency (MPRF) using a stationary tip in different treatment strategies on porcine skin.

METHODS

Two Bama miniature pigs received MPRF treatment with two types of stationary tips in eight groups of parameters (power, duration, and pass) on dorsal skin. Skin samples were collected from each treatment zone immediately, at 1 week and 1, 3, and 6 months after treatment. Hematoxylin and eosin (HE) and Masson staining were performed to assess histologic changes as well as neocollagenesis. The dynamic changes of heat shock protein 47 (HSP47) and heat shock protein 72 (HSP72) were also detected by immunohistochemistry.

RESULTS

Skin damage increased with pulse energy, duration, and pass. Longer durations or repeated treatments may cause particularly severe skin damage. During the wound healing process, the newborn collagen of the dermis is rearranged. The distribution of HSP47 and HSP72 was consistent with the extent of collagen remodeling. It peaked 1 month after treatment.

CONCLUSION

MPRF can effectively cause epidermal ablation, dermal collagen hyperplasia, and remodeling. Increasing power should be the first choice when increasing treatment intensity. For longer durations or repeated treatments, caution should be taken to avoid excessive skin trauma.

Clinical factors influencing the effectiveness of microplasma fractional radiofrequency treatment for atrophic acne scars: A retrospective analysis

BACKGROUND

Microplasma fractional radiofrequency (MP FRF) technology has been increasingly used for acne scars. Nevertheless, little evidence has analyzed the factors influencing its effectiveness before and during treatment.

AIMS

To evaluate the clinical factors affecting the effectiveness of MP FRF therapy for atrophic acne scars.

METHODS

We analyzed retrospectively the clinical data of 79 acne scar patients treated with MP FRF technology. The outcome of interest included the effectiveness and adverse events after MP FRF treatment. Multivariable logistic regression was utilized to evaluate clinical factors associated with effectiveness after the initial session.

RESULTS

All patients received 115 sessions of MP FRF therapy (average: 1.5 sessions). Twenty-eight (35.4%) patients improved moderately to excellently after one session. We found that the severe grade before treatment was negatively correlated with the effectiveness according to Goodman-Baron qualitative scores (OR = 0.02, 95% CI [0.001, 0.37], p = 0.009). The presence of icepick scars was also a negative correlation factor for the effectiveness (OR = 0.06, 95% CI [0.004, 1.00], p = 0.049). Furthermore, after excluding the effects of icepick scars and Goodman-Baron scores before treatment, ECCA scores were also correlated with effectiveness (OR = 1.04, 95% CI [1.01, 1.06], p = 0.009).

CONCLUSION

MP FRF therapy was effective in treating atrophic acne scars with no permanent adverse events. The severity of Goodman-Baron qualitative scores and icepick scars were independent clinical factors affecting effectiveness, suggesting the possible requirement for additional treatments other than MP FRF for severe acne scars and icepick scars.

The use of fractional radiofrequency in Asian patients to improve skin texture

BACKGROUND AND OBJECTIVES

Fractional radiofrequency devices have been demonstrated to improve skin texture, such as smoothness, rhytides, brightness, and atrophic acne scars, by increasing dermal thickness, dermal collagen content, and dermal fibrillin content. The objective of the study is to assess the efficacy and adverse effects of this device on Asian patients of skin type III and IV with skin textural changes.

MATERIALS AND METHODS

The study was designed as a prospective, open-labeled single-arm study, which was conducted with 20 Chinese patients aged 21-60 years and having irregularities in their skin texture, rhytides, and acne scars. The patients received six treatments at intervals of 4 weeks. Treatment was initiated with the maximum energy tolerated, which was then adjusted during the course of treatment if the patients felt excessive discomfort. A total of two passes were delivered in each session. Physician assessment results and standardized photographs were collected at the baseline, after all treatment visits, and at 1, 2, and 6 months after the final treatment visit.

RESULTS

A total of 17 patients completed the study according to the established protocol. At the 6-month follow-up, 71% of patients were satisfied and 24% of patients were very satisfied with the received treatments, and the treatment physician reported varying degrees of improvement based on the global assessment scale in 60% of the subjects. While the anticipated side effects, such as erythema, edema, pinpoint bleeding, scab formation, and flare of acne, were noted in the patients, no serious adverse effects occurred.

CONCLUSION

The use of fractional radiofrequency improves skin texture and is safe for use in Asian patients of skin type III and IV. No long-term serious adverse effects were noted.

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.

Laser-Assisted Drug Delivery in the Treatment of Scars, Rhytids, and Melasma: A Comprehensive Review of the Literature

Although broad reviews on laser-assisted drug delivery (LADD) have been published in the past, an updated focused examination of its utility in the context of common, treatment-resistant, dermatologic conditions has not been published. This article reports a comprehensive scoping review of the potential benefits of LADD compared to laser or drug monotherapy for the treatment of 3 such conditions: scars, rhytids, and melasma. A PubMed (National Institutes of Health; Bethesda, MD) search was conducted for keywords including "laser-assisted drug delivery," "scar," "rhytid," and "melasma." Out-of-scope studies were excluded. To evaluate the efficacy of LADD for the treatment of scars, relevant articles were categorized by scar type: hypertrophic/keloid, atrophic, and hypopigmented. LADD, with both ablative and nonablative laser types, was studied in combination with corticosteroids, botulinum toxin-A (BTX-A), 5-fluorouracil, 5-aminolevulinic acid photodynamic therapy, stem cells, platelet-rich plasma, and prostaglandin analogs for the treatment of scars. Some randomized controlled trials demonstrated the efficacy of LADD, whereas others showed no significant differences in clinical outcomes but demonstrated reduced adverse effects. Regarding rhytids, laser treatment has been combined with various cosmeceuticals, including poly-L-lactic acid, topical retinaldehyde, and topical BTX-A. The studies reviewed supported the use of LADD with these drugs over monotherapy. Some studies showed that LADD was effective for the absorption of drugs such as poly-L-lactic acid and BTX-A which are often not effective topically. For melasma treatment, LADD with tranexamic acid and hydroquinone was superior in some studies, but not significantly different than monotherapy in other studies. LADD with certain drugs could be considered to treat scars, rhytids, and melasma.

LEVEL OF EVIDENCE: 5

Comparative efficacy and safety of six photoelectric therapies for the atrophic acne scars: A network meta-analysis

Objectives

This network meta-analysis assessed the relative efficacy and safety of six common photoelectric therapies including 1064-nm neodymium-doped yttrium aluminum garnet (Nd: YAG), fractional carbon dioxide laser(FSCO2), fractional micro-plasma radiofrequency(Plasma), micro-needling fractional radiofrequency (MRF), 1550nm or 1540nm erbium-glass non-ablative fractional laser (NAFL) fractional erbium-doped yttrium aluminum garnet (Er: YAG).

Methods

A comprehensive search to identify relevant studies was conducted using four electronic databases. Outcome measures were extracted based on subjective and objective indexes, including the dermatologists’ evaluation(DE), the patients’ overall satisfaction(PS), VAS score, and Postinflammatory hyperpigmentation (PIH).

Results

Eleven published clinical research studies, involving 405 patients were included in this study. Ranking of DE from large to small is as follows: Nd: YAG, FSCO2, Er: YAG, Plasma, NAFL, MRF. In terms of PS, the rand from high to low can be described as follows: Er: YAG, Nd: YAG, FSCO2, Plasma, NAFL, MRF. In connection with the sequencing of adverse events, pain severity from slight to severe as follows: Er:YAG, Nd:YAG, FSCO2, NAFL, MRF, Plasma. The probability of having PIH are presented in order from lowest to highest as follows: MRF, Plasma, Nd: YAG, NAFL, Er: YAG, FSCO2.

Conclusion

FSCO2 remains the mainstream of potentially curative treatment, then again Nd: YAG and Er: YAG require greater efforts to prove their superior effectiveness. NAFL might be appropriate for mild and moderate improvement with its strengths of good tolerance while Plasma fits into patients with higher pain thresholds but an expectation of higher results. MRF has not given expression on absolute predominance for the present.

Registration

PROSPERO CRD42021242160

(available from https://www.crd.york.ac.uk/prospero).

Visualization of energy-based device-induced thermal tissue alterations using bimodal ex-vivo confocal microscopy with digital staining. A proof-of-concept study

BACKGROUND

Ex-vivo confocal microscopy (EVCM) enables examination of tissue alterations immediately after treatment with energy-based devices (EBDs). This proof-of-concept study aimed to describe EBD-induced tissue effects in ex-vivo porcine skin after treatment with microneedle radiofrequency (MNRF) and ablative fractional CO₂ -laser (AFL) using EVCM.

MATERIALS AND METHODS

Ex-vivo porcine skin was treated with MNRF and AFL. Three cryosections from each intervention were stained with acridine orange (AO) and scanned with EVCM. Reflectance confocal microscopy (RCM, 638 nm) and fluorescence confocal microscopy (FCM, 488 nm) images were captured and evaluated individually, after image fusion, and after digital hematoxylin and eosin (H&E) staining.

RESULTS

Bimodal EVCM was able to visualize EBD-induced thermal alterations in porcine skin. In RCM mode, the full width and depth of the vertically aligned microscopic treatment zones (MTZs) were displayed with clear demarcation to surrounding intact skin. In FCM mode, the ablation of the epidermis after AFL was prominent in contrast with the almost intact epidermis observed in MNRF treated skin. In fusion mode, fluorescence signal from AO marked the surrounding coagulation zone (CZ) from both interventions, with enhanced discrimination between ablation and coagulation. Digitally H&E-stained images closely resembled conventional histopathology but proved superior in terms of visualization of the CZ.

CONCLUSION

Bimodal EVCM with digital H&E-staining facilitates the identification and qualitative evaluation of thermal alterations induced by treatment with EBD. By providing high-resolution images comparable to standard histology, EVCM is a useful tool in the research and development of EBD to visualize and evaluate device-tissue interactions.

Thermal effects of percutaneous application of plasma/radiofrequency energy on porcine dermis and fibroseptal network

Background

Skin laxity is one of the defining characteristics of aging and can be the result of various factors including intrinsic aging, genetics, diet, stress, lifestyle, sun exposure, weight fluctuations, and smoking. Recent reports suggest the ability of subdermal energy application to reduce skin laxity. Thermal energy can be delivered using different devices including lasers, radiofrequency (RF) monopolar and bipolar devices, and plasma/RF devices. Plasma‐based energy platforms generate a plasma gas, allowing heat to be applied to the tissue. This study focused on the evaluation of thermal effect of plasma/RF compared to a monopolar RF device applied percutaneously to the subdermis and connective fibroseptal network in a porcine model.

Methods

The subdermal application of energy was conducted using a plasma/RF system and a monopolar RF system. Both low and high energy/temperature settings were evaluated in dynamic and stationary modes. Histomorphometry was used to determine the depth of thermal effect associated with each treatment setting.

Results

Both dermis and fibroseptal network tissue exhibited the presence of microscopically thermally treated zones. There were no significant differences in average and maximum depths of thermal effect between the different handpieces and electrosurgical systems used for all treatment settings.

Conclusions

No significant differences in the thermal effect between plasma/RF and monopolar RF systems were observed, suggesting that plasma/RF systems can be safely used for the percutaneous application of energy in the subcutaneous space.

A novel ablative radiofrequency microplasma nonsurgical blepharoplasty for dermatochalasis

Dermatochalasis (DC) is part of the aging process of the eyelids, characterized by lax, redundant, and overhanging excess eyelid skin. Mostly, it is treated by surgical blepharoplasty. Lately alternative nonsurgical blepharoplasty technologies have been introduced. In this study, we evaluated the efficacy and safety of a novel noninvasive RF microplasma technology for upper eyelid DC. A prospective single center study included 17 patients with moderate to severe upper eyelid DC. Subjects were treated by controlled micro-plasma sparks via a single tip leading to superficial ablation and coagulation at the treatment area. One to three treatment sessions at 2 months interval were performed. Three blinded observers evaluated the photographs taken at baseline and at 6 to 8 months follow-up visit following the final treatment session. Treatment efficacy was assessed using a 4-point grading scale. Seven out of 17 patients (41%) treated for DC by the single microplasma spark exhibited a 2 grade improvement on a 4 point DC scale. 10 out of 17 (59%) patients showed a single grade improvement on a 4 point DC scale. No adverse side effects were observed. Noninvasive ablative microplasma may offer safe and effective therapy for upper eyelid DC.

Local Tolerability and Performance Evaluation in Domestic Pigs of a Fractional Radiofrequency Device for Dermatologic Treatment

Information on the safety of energy-based dermatological surgical devices in domestic pigs, and fractional radiofrequency (RF) devices in particular, is very limited. The aim of this study was to evaluate in a GLP-compliant study in domestic pigs the local reaction and performance of a novel fractional RF device. Five female domestic pigs were subjected to fractional RF pulses, using different energy and pulse durations and depth of penetration of the pulses. The animals were evaluated clinically and histologically at different time points (days 0, 1, 3, 7, and 14) postenergy exposure. There were no microscopic or macroscopic local adverse effects in any tested power settings, and there was time-related progressive healing, reaching complete macroscopic and microscopic healing by 7 days postapplication. As expected, there was power-related progressive increase in the incidence of ablation (destruction of skin tissue by vaporization) and coagulative necrosis of the dermis from low to high power setting. This comprehensive study, using multiple power settings (both ablative and coagulative) and several time points, will be of benefit for future studies evaluating new fractional RF devices.

Enhanced topical cutaneous delivery of indocyanine green after various pretreatment regimens: comparison of fractional CO2 laser, fractional Er:YAG laser, microneedling, and radiofrequency

Different devices have been used to enhance topical drug delivery. Aim of this study was to compare the efficacy of different skin pretreatment regimens in topical drug delivery. In six ex vivo human abdominal skin samples, test regions were pretreated with fractional CO₂ and Er:YAG laser (both 70 and 300 μm ablation depth, density of 5%), microneedling (500 μm needle length), fractional radiofrequency (ablation depth of ± 80–90 μm), and no pretreatment. The fluorescent agent indocyanine green (ICG) was applied. After 3 h, fluorescence intensity was measured at several depths using fluorescence photography. Significantly higher surface fluorescence intensities were found for pretreatment with fractional Er:YAG and CO₂ laser and for microneedling vs. no pretreatment (p < 0.05), but not for radiofrequency vs. no pretreatment (p = 0.173). Fluorescence intensity was highest for the Er:YAG laser with 300 μm ablation depth (mean 38.89 arbitrary units; AU), followed by microneedling (33.02 AU) and CO₂ laser with 300 μm ablation depth (26.25 AU). Pretreatment with both lasers with 300 μm ablation depth gave higher fluorescence intensity than with 70 μm ablation depth (Er:YAG laser, 21.65; CO₂ laser, 18.50 AU). Mean fluorescence intensity for radiofrequency was 15.27 AU. Results were comparable at 200 and 400 μm depth in the skin. Pretreatment of the skin with fractional CO₂ laser, fractional Er:YAG laser, and microneedling is effective for topical ICG delivery, while fractional radiofrequency is not. Deeper laser ablation results in improved ICG delivery. These findings may be relevant for the delivery of other drugs with comparable molecular properties.

The biophysical effects of localized electrochemical therapy on porcine skin

BACKGROUND

Minimally-invasive methods to treat scars address a common pathway of altering collagen structure, leading to collagen remodeling.

OBJECTIVE

In this study, we employed in situ redox chemistry to create focal pH gradients in skin, altering dermal collagen, in a process we refer to as electrochemical therapy (ECT). The effects of ECT to induce biochemical and structural changes in ex vivo porcine skin were examined.

METHODS

During ECT, two platinum electrodes were inserted into fresh porcine skin, and following saline injection, an electrical potential was applied. pH mapping, high frequency ultrasonography, and two photon excitation microscopy and second harmonic generation (SHG) microscopy were used to evaluate treatment effects. Findings were correlated with histology.

RESULTS

Following ECT, pH mapping depicted acid and base production at anode and cathode sites respectively, with increasing voltage and application time. Gas formation during ECT was observed with ultrasonography. Anode sites showed significant loss of SHG signal, while cathode sites showed disorganized collagen structure with fewer fibrils emitting an attainable signal. Histologically, collagen denaturation at both sites was confirmed.

CONCLUSION

We demonstrated the production of in situ acid and base in skin occurring via ECT. The effects chemically and precisely alter collagen structure through denaturation, giving insight on the potential of ECT as a simple, low-cost, and minimally-invasive means to remodel skin and treat scars.

Application of reflectance confocal microscopy to investigate the non-ablative, micro-ablative, and ablative effects of CO2 fractional laser irradiation on skin

CO₂ fractional laser, as an ablative fractional laser, is commonly used in cosmetic treatment. We applied CO₂ fractional laser irradiation to skin in vitro and used reflectance confocal microscopy (RCM) to image and detect the presence of any non-ablative, micro-ablative and ablative effects, in order to better understand the features of a CO₂ fractional laser. In vitro irradiation of foreskin was performed using a CO₂ fractional laser. Foreskin specimens were divided into 4 groups that received different amounts of irradiation energy, based on the number of irradiation passes they received: 5, 10, 15, and 20 passes, respectively. This corresponds to fluence energy of 16.3, 32.6, 48.9, 65.3 J/cm². Immediately after irradiation, digital microscopy (DM), RCM, and histopathology were performed to observe whether the non-ablative, micro-ablative, and ablative phenomenon occurred, and the injury features of MTZs. Immediately after CO₂ fractional laser irradiation, RCM and DM showed that when the numbers of passes were 5 and 10, a micro-ablative column (MAC) could not be observed or was very small. We mainly observed a thicker thermal coagulation zone (TCZ), representing non-ablative or micro-ablative effects. When the number of passes were increased to 15 and 20, the MAC was significantly enlarged and surrounded by a TCZ of medium thickness, representing ablative effects. For the first time, this study used RCM and DM to demonstrate that a CO₂ fractional laser could achieve non-ablative, micro-ablative, and ablative effects on irradiated skin via different energy levels.

Advances in the treatment of traumatic scars with laser, intense pulsed light, radiofrequency, and ultrasound

Traumatic scarring is one of the most common complications after soft tissue injury caused by burns and trauma, which affects tens of millions of people worldwide every year. Traumatic scars diminish the quality of life due to disfigurement, symptoms of pain and itch, and restricted motion. The pathogenesis and pathophysiology of traumatic scar remain elusive. The management for traumatic scars is comprised of surgical and non-surgical interventions such as pressure therapy, silicone, corticosteroid, and radiotherapy, which are chosen by clinicians based on the physical examinations of scars. Recently, great progress in treating traumatic scars has been achieved by the development of novel technologies including laser, intense pulsed light (IPL), radiofrequency, and ultrasound. The aim of this review article was to summarize the advances of these technologies for traumatic scars intervention.

Treatment of atrophic acne scarring with fractional micro-plasma radio-frequency in Chinese patients: A prospective study

BACKGROUND

Acne scarring is a common disfiguring sequela of acne vulgaris which can lead to serious psychosocial problems and have a negative effect on patients' quality of life. Although a variety of approaches can be used to treat atrophic acne scars, disadvantages such as long-healing time, dyspigmentation, infections, and prolonged erythema make these treatments unsatisfactory especially for Asians. Fractional micro-plasma radio-frequency is a novel technology that produces minor ablation to the epidermis to promote rapid re-epithelialization, while the radio-frequency evoked thermal effect can stimulate regeneration and remodeling of dermal fibroblasts.

OBJECTIVE

To evaluate the clinical effectiveness and safety of micro-plasma radio-frequency for the treatment of facial acne scars in Chinese patients.

MATERIALS AND METHODS

A total of 95 patients with facial atrophic acne scars were treated by micro-plasma radio-frequency using three sessions at 2-month intervals. Patients were seen 1 week after each treatment and 1, 3, 6 months after the final treatment. Improvement was assessed by three independent dermatologists who compared photographs taken before the first treatment and 6 months after the last treatment. Adverse effects were evaluated by a dermatologist who did not participated in the study. Patients also provided self-evaluation of satisfaction levels at the last follow-up visit.

RESULTS

A total of 86 patients with atrophic acne scars completed the entire study. There was a significant improvement in acne scars after three treatments. The mean score of ECCA grading scale (Echelle d'Evaluation Clinique des Cicatrices d'Acné) was reduced from 107.21 to 42.27 (P < 0.05). A total of 15 of 86 patients showed more than 75% improvement, 57 patients showed 50-75% improvement, and 14 patients showed 25-50%. After three treatments, all subjects showed improvements in spots, large pores, texture, UV damage, red areas, and porphyrin fluorescence. Pain, erythema, edema, effusion, and scab formation were observed in all patients. The average pain score on a visual analog scale was 6.14 ± 1.12 and all patients tolerated the treatments. The average duration of erythema was 6.26 ± 0.92 days. Hyperpigmentation, hypopigmentation, infections, and worsening of scarring were not seen. All patients were either "very satisfied" or "satisfied" with the treatment outcomes.

CONCLUSIONS

Fractional micro-plasma radio-frequency is an effective and safe treatment for acne scars, and might be a good choice for patients with darker skin. Lasers Surg. Med. 50:844-850, 2018. © 2018 Wiley Periodicals, Inc.

Objective evaluation of the efficacy of a non-ablative fractional 1565 nm laser for the treatment of deliberate self-harm scars

Scars resulting from deliberate self-harm (DSH) represent therapeutically challenging forms of scarring due to their highly variable patterns, with no official therapeutic guidelines available. In this pilot study, we aimed to evaluate the effectiveness and safety of a non-ablative fractional Er:glass 1565 nm laser, as a potential new, minimal-invasive approach for the improvement of DSH scars. Sixteen Caucasians suffering from mature DSH scars were included in this clinical study. Patients received a total of three treatments using a non-ablative fractional 1565 nm Er:glass laser every 4 weeks, employing two passes (300 μbeams/cm², 40 mJ, onto the scar; 150 μbeams/cm², 50 mJ, overall area). Measurements included questionnaires (DLQI, POSAS), digital photography, and objective three-dimensional analysis using PRIMOS and VECTRA software at baseline, 1 and 6 months after treatment. PRIMOS objective measurements showed highly significant changes in scar surface with a reduction of atrophic lesions by 27.5% at 6 months follow-up (FU), a decrease in scar height by 42.7% at 6 months FU, resulting in an overall diminished skin irregularity dropping from 678.3 μm at baseline to 441.6 μm throughout the course of the study (p = <0.001 respectively). Improvements in objective measurements were supported by clinical evaluation of scar parameters and showed a strong correlation with enhanced life quality of treated patients. Procedures were well-tolerated, with no lasting negative side effects and little to no downtime. The use of a fractional non-ablative 1565 nm Er:glass laser represents a promising and safe approach for the therapy of DSH scars. Although these scars will never fully resolve, their appearance can be significantly improved to a cosmetically and socially more acceptable appearance.

Fractional microplasma radiofrequency technology for non-hypertrophic post-burn scars in Asians: A prospective study of 95 patients

BACKGROUND

Laser and other energy devices are emerging, minimally invasive treatments for scars. Among the various techniques, fractional microplasma radiofrequency technology (FMRT) has proven to be an effective treatment option for various types of scars and skin conditions such as rhytids, striae distensae, and hyperpigmentation.

OBJECTIVE

This prospective clinical trial was designed to evaluate the efficacy and safety of FMRT for treating non-hypertrophic post-burn scars in the Asian population.

METHOD

All patients underwent three to five treatment sessions at various intervals of 8-16 weeks. The Patient and Observer Scar Assessment Scales (POSAS) [20] were used to evaluate changes in burn scars pre-and post-FMRT treatment.

RESULTS

A total of 95 patients completed the study. The overall response rate was 86.3% (82/95). The total POSAS scores before and after 6 months of treatment were 53.41 ± 6.28 and 46.35 ± 5.30, respectively. There was statistically significant improvement in scar color, thickness, and pliability. There was no improvement in vascularization, pain, or itching. Complications included prolonged post-inflammatory hyperpigmentation, acne eruption, herpes simplex eruption, and abnormal hair growth. No severe adverse events, such as acute skin infection, hypertrophic scarring, or depigmentation, were observed.

CONCLUSION

FMRT is an efficacious, safe treatment for non-hypertrophic burn scars in the Asian population. Lasers Surg. Med. 49:563-569, 2017. © 2017 Wiley Periodicals, Inc.

The effect of pre-operative topical anaesthetic cream on the ablative width and coagulative depth of ablative fractional resurfacing laser

Topical anaesthetic cream (TAC) is commonly used as a pre-treatment of ablative fractional resurfacing (AFR) laser. Most of anaesthetic cream contains distilled water as major component. Therefore, pre-operative TAC may interfere the photothermal reaction in the skin treated with fractional carbon-dioxide (FCO₂) laser and fractional erbium-doped yttrium aluminium garnet (FEr:YAG) laser. The objective of the study was to compare the ablative width (AW) and coagulative depth (CD) of AFR laser with and without pre-treatment with TAC. Four Thai females who underwent abdominoplasty were included in the study. The excised skin of each subject was divided into four areas. TAC (eutectic mixture of local anaesthesia; EMLA) with 1-h occlusion was applied only on the first and second areas. The first and third areas were treated with FCO₂ at 15 mj and 5% density. The second and fourth areas were treated with FEr:YAG at 28 J/cm² and 5% density. Six biopsied specimens were obtained from each area. A total of 96 specimens (24 specimens from each area) were collected from four patients and examined randomly by two dermatopathologists. The ablative width and coagulative depth from each specimen were determined. In FCO₂-treated specimens, the mean AW of the specimens that were pre-treated with TAC and control was 174.86 ± 24.57 and 188.52 ± 41.32 μm. The mean CD of the specimens that were pre-treated with TAC and control was 594.96 ± 111.72 and 520.03 ± 147.40 μm. There were no significant differences in AW and CD between both groups (p = 0.53 and p = 0.15). In FEr:YAG-treated specimens, the mean AW of the specimens that were pre-treated with TAC and control was 381.11 ± 48.02 and 423.65 ± 60.16 μm. The mean CD of the specimens that were pre-treated with TAC and control was 86.03 ± 29.44 and 71.59 ± 18.99 μm. There were no significant differences in AW and CD between both groups (p = 0.16 and p = 0.24). The pre-treatment with TAC provided no statistically difference from the control group on AW and CD of both FCO₂ and FEr:YAG laser irradiation. However, there was a tendency to have narrower AW and deeper CD of the areas that were pre-treated with TAC when comparing to that of the control.

The Efficacy and Safety of Fractional CO₂ Laser Combined with Topical Type A Botulinum Toxin for Facial Rejuvenation: A Randomized Controlled Split-Face Study

Objective. We evaluated synergistic efficacy and safety of combined topical application of Botulinum Toxin Type A (BTX-A) with fractional CO₂ laser for facial rejuvenation. Methods. Twenty female subjects were included for this split-face comparative study. One side of each subject's cheek was treated with fractional CO₂ plus saline solution, and the other side was treated with fractional CO₂ laser plus topical application of BTX-A. Patients received one session of treatment and evaluations were done at baseline, one, four, and twelve weeks after treatment. The outcome assessments included subjective satisfaction scale; blinded clinical assessment; and the biophysical parameters of roughness, elasticity, skin hydration, transepidermal water loss (TEWL), and the erythema and melanin index. Results. BTX-A combined with fractional CO₂ laser sides showed higher physician's global assessment score, subject satisfaction score, roughness, skin hydration, and skin elasticity compared to that of fractional CO₂ plus saline solution side at 12 weeks after treatment. TEWL and erythema and melanin index showed no significant differences between two sides at baseline, one, four, and twelve weeks after treatment. Conclusion. Topical application of BTX-A could enhance the rejuvenation effect of fractional CO₂ laser.