In vivo histological evaluation of a novel ablative fractional resurfacing device

Fractional laser-assisted drug delivery: Laser channel depth influences biodistribution and skin deposition of methotrexate

BACKGROUND AND OBJECTIVE

Ablative fractional laser (AFXL) facilitates delivery of topical methotrexate (MTX). This study investigates impact of laser-channel depth on topical MTX-delivery.

MATERIALS AND METHODS

MTX (1% [w/v]) diffused for 21 hours through AFXL-exposed porcine skin in in vitro Franz Cells (n = 120). A 2,940 nm AFXL generated microscopic ablation zones (MAZs) into epidermis (11 mJ/channel, MAZ-E), superficial-dermis (26 mJ/channel, MAZ-DS), and mid-dermis (256 mJ/channel, MAZ-DM). High performance liquid chromatography (HPLC) was used to quantify MTX deposition in full-thickness skin, biodistribution profiles at specific skin levels, and transdermal permeation. Fluorescence microscopy was used to visualize UVC-activated MTX-fluorescence (254 nm) and semi-quantify MTX distribution in skin.

RESULTS

AFXL increased topical MTX-delivery (P < 0.001). Without laser exposure, MTX-concentration in full-thickness skin was 0.07 mg/cm(2) , increasing sixfold (MAZ-E), ninefold (MAZ-DS), and 11-fold (MAZ-DM) after AFXL (P < 0.001). Deeper MAZs increased MTX-concentrations in all skin layers (P < 0.038) and favored maximum accumulation in deeper skin layers (MAZ-E: 1.85 mg/cm(3) at 500 μm skin-level vs.

MAZ-DM

3.75 mg/cm(3) at 800 μm, P = 0.002). Ratio of skin deposition versus transdermal permeation remained constant, regardless of MAZ depth (P = 0.172). Fluorescence intensities confirmed MTX biodistribution through coagulation zones and into surrounding skin, regardless of thickness of coagulation zones (6-47 μm, P ≥ 0.438).

CONCLUSION

AFXL greatly increases topical MTX-delivery. Deeper MAZs deliver higher MTX-concentrations than superficial MAZs, which indicates that laser channel depth may be important for topical delivery of hydrophilic molecules. Lasers Surg. Med. 48:519-529, 2016. © 2016 Wiley Periodicals, Inc.

Effects of deviation from focal plane on lesion geometry for ablative fractional photothermolysis

BACKGROUND AND OBJECTIVE

Fractional Photothermolysis (FP) is a method of skin treatment that generates a thermal damage pattern consisting of multiple columns of thermal damage, also known as microscopic treatment zones (MTZs). They are very small in diameter and are generated by application of highly focused laser beams. In order to obtain the smallest spot size, the treatment should be performed in the focal plane. Any deviation from the focal plane (DFP) results in an increase of spot size. FP devices typically utilize distance holders in order to facilitate exposures at this specific location. In spite of the use of distance holders, DFP can occur. In particular, variations of contact pressure to the skin surface and anatomical treatment areas of high surface curvature may be prone to DFP during FP treatments. The impact of such distance variation on lesion geometry, such as depth and diameter of the thermal injury, has not previously been evaluated. The objective of this study was to investigate the relation between DFP and the resulting lesion geometry for a selected ablative fractional device.

MATERIAL AND METHODS

A handpiece of an ablative fractional laser (DeepFX, UltraPulse Encore, Lumenis, Yokneam, Israel) was mounted to a rigid stand. Full thickness human skin obtained from abdominoplasty was mounted to a separate stand perpendicular to the handpiece. The tissue stand allowed the distance between the handpiece and the tissue to be adjusted to produce a variation up to ±3 mm from the focal plane. A 1 × 1 cm(2) scanning area of 169 MTZs, 50 mJ energy per MTZ, 120 μm nominal spot size, was applied at -3, -2, -1, 0, +1, +2, and +3 mm deviated from the focal plane. Minus (-) and plus (+) signs indicate decreasing and increasing distance between the handpiece and the tissue, respectively. Depth and diameter of the laser induced tissue lesions were assessed and quantified.

RESULTS

DFPs produced a significant alteration of the lesion geometry. DFPs of -3, -2, -1, 0, +1, +2, +3 mm resulted in average lesion depths of 1,020 (-40%), 1,180 (-31%), 1,400 (-18%), 1,700 (0%), 1,620 (-5%), 780 (-55%), 680 (-60%) µm, and average lesion diameters of 314 (+26%), 311 (+25%), 273 (+10%), 248 (0%), 256 (+3%), 316 (+27%), 359 (+44%) µm, respectively. The underlined values represent the focal plane. The percentage changes relative to values at focal plane are in parentheses.

CONCLUSIONS

A relatively minor DFP has a marked impact on the thermal injury profile, including lesion depth and diameter, of the laser-exposed tissue. Such marked changes of the thermal injury profile might affect the wound healing, safety, and efficacy of ablative fractional resurfacing procedures. Clinicians should carefully maintain the focal plane during ablative fractional treatment for reproducible results. The presented data are device specific and the clinical impact of such alteration of thermal injury profile warrants further investigation. Lasers Surg. Med. 48:555-561, 2016. © 2016 Wiley Periodicals, Inc.

The role of lasers and intense pulsed light technology in dermatology

The role of light-based technologies in dermatology has expanded dramatically in recent years. Lasers and intense pulsed light have been used to safely and effectively treat a diverse array of cutaneous conditions, including vascular and pigmented lesions, tattoos, scars, and undesired hair, while also providing extensive therapeutic options for cosmetic rejuvenation and other dermatologic conditions. Dermatologic laser procedures are becoming increasingly popular worldwide, and demand for them has fueled new innovations and clinical applications. These systems continue to evolve and provide enhanced therapeutic outcomes with improved safety profiles. This review highlights the important roles and varied clinical applications that lasers and intense pulsed light play in the dermatologic practice.

Lasers and ancillary treatments for scar management: personal experience over two decades and contextual review of the literature. Part I: Burn scars

The formation of a wide range of excessive scars following various skin injuries is a natural consequence of healing. Scars resulting from surgery or trauma affect approximately 100 million people per annum in the developed world and can have profound physical, aesthetic, psychological and social consequences. Thus, scar treatment is a priority for the plastic surgeon. We aim to explore new approaches to the management of such scarring. The senior authors current use of laser technology, chemotherapeutic agents, pharmacotherapy and cryosurgery will be reviewed. This is placed in the context of the current literature and evidence base and is illustrated with case studies, starting with burns scars in part I, and focusing on keloid and hypertrophic scars in part II, acne scars in part III and finally pigmented scars in part IV. In Part I we focus on burns scar treatment with fractional ablative 10,600 nm wavelength carbon dioxide (CO2) laser therapy.

Fractional Carbon Dioxide Laser in Treatment of Acne Scars

BACKGROUND:

Scars appear as a result of skin damage during the process of the skin healing. There are two types of acne scars, depending on whether there is a loss or accumulation of collagen: atrophic and hypertrophic. In 80-90% it comes to scars with loss of collagen compared to smaller number of hypertrophic scars and keloids.

AIM:

The aim of the study was to determine efficiency and safety of fractional carbon dioxide laser in the treatment of acne scars.

MATERIAL AND METHODS:

The study was carried out in Acibadem Sistina Clinical Hospital, Skopje at the Department of Dermatovenerology, with a total of 40 patients treated with fractional carbon dioxide laser (Lutronic eCO2). The study included patients with residual acne scars of a different type.

RESULTS:

Comedogenic and papular acne in our material were proportionately presented in 50% of cases, while the other half were the more severe clinical forms of acne - pustular inflammatory acne and nodulocystic acne that leave residual lesions in the form of second, third and fourth grade of scars.

CONCLUSION:

The experiences of our work confirm the world experiences that the best result with this method is achieved in dotted ice pick or V-shaped acne scars.

Efficacy of Punch Elevation Combined with Fractional Carbon Dioxide Laser Resurfacing in Facial Atrophic Acne Scarring: A Randomized Split-face Clinical Study

Background:

A number of treatments for reducing the appearance of acne scars are available, but general guidelines for optimizing acne scar treatment do not exist. The aim of this study was to compare the clinical effectiveness and side effects of fractional carbon dioxide (CO₂) laser resurfacing combined with punch elevation with fractional CO₂ laser resurfacing alone in the treatment of atrophic acne scars.

Materials and Methods:

Forty-two Iranian subjects (age range 18–55) with Fitzpatrick skin types III to IV and moderate to severe atrophic acne scars on both cheeks received randomized split-face treatments: One side received fractional CO₂ laser treatment and the other received one session of punch elevation combined with two sessions of laser fractional CO₂ laser treatment, separated by an interval of 1 month. Two dermatologists independently evaluated improvement in acne scars 4 and 16 weeks after the last treatment. Side effects were also recorded after each treatment.

Results:

The mean ± SD age of patients was 23.4 ± 2.6 years. Clinical improvement of facial acne scarring was assessed by two dermatologists blinded to treatment conditions. No significant difference in evaluation was observed 1 month after treatment (P = 0.56). Their evaluation found that fractional CO₂ laser treatment combined with punch elevation had greater efficacy than that with fractional CO₂ laser treatment alone, assessed 4 months after treatment (P = 0.02). Among all side effects, coagulated crust formation and pruritus at day 3 after fractional CO₂ laser treatment was significant on both treatment sides (P < 0.05).

Conclusion:

Concurrent use of fractional laser skin resurfacing with punch elevation offers a safe and effective approach for the treatment of acne scarring.

Ablative CO2 fractional resurfacing in treatment of thermal burn scars: an open-label controlled clinical and histopathological study

INTRODUCTION

Burn scars can cause permanent disfiguring problems with limited treatments available.

OBJECTIVES

To assess and correlate the clinical and histopathological effects of fractional CO2 laser on thermal burns in a controlled study.

METHODS

Fifteen patients 11 with hypertrophic and four with keloidal scars received three CO2 fractional laser sessions every 4-6 weeks. Half of the scar was untreated as a control. Clinical evaluation by Vancouver, PSOAS scores, and photography before, monthly, and 3 months after the last laser session was performed. Ten patients were evaluated histopathologically by standard H&E, Masson trichrome, and Elastica von Gieson special stains.

RESULTS

Hypertrophic scars (HTSs) showed textural improvement and a significant decrease of Vancouver, POSAS observer, and patient scores by the end of follow-up period in the laser-treated area (P = 0.011, 0.017 and 0.018, respectively) unlike keloidal scars. Histopathology revealed significant decrease in scar thickness in HTSs only (P < 0.001) as well as a significant decrease in collagen bundle thickness and density in the upper dermis in both types of scars.

CONCLUSIONS

Fractional CO2 laser is a possible safe and effective modality for the treatment of hypertrophic burn scars with improvement achieved both clinically and histopathologically.

Usefulness of Skin Explants for Histologic Analysis after Fractional Photothermolysis

Background

Fractional laser resurfacing treatment has been extensively investigated and is widely used. However, the mechanism underlying its effects is poorly understood because of the ethical and cosmetic problems of obtaining skin biopsies required to study the changes after laser treatment.

Objective

To evaluate the usefulness of human skin explants for the investigation of fractional photothermolysis.

Methods

Full-thickness discarded skin was treated in 4 ways: no treatment (control), fractional carbon dioxide laser, fractional Er:YAG laser, and fractional 1,550-nm erbium-doped fiber laser. Both treated and non-treated skin samples were cultured ex vivo at the air-medium interface for 7 days. Frozen tissue was sectioned and stained with hematoxylin & eosin for histologic examination and nitro blue tetrazolium chloride for viability testing.

Results

Skin explants cultured for up to 3 days exhibited histologic changes similar to those observed in in vivo studies, including microscopic treatment zones surrounded by a thermal coagulation zone, re-epithelialization, and formation of microscopic epidermal necrotic debris. However, the explant structure lost its original form within 7 days of culture. The viability of skin explants was maintained for 3 days of culture but was also lost within 7 days.

Conclusion

The skin explant model may be a useful tool for investigating the immediate or early changes following fractional photothermolysis, but further improvements are required to evaluate the long-term and dermal changes.

Hair regrowth through wound healing process after ablative fractional laser treatment in a murine model

BACKGROUND AND OBJECTIVE

Alopecia is one of the most common dermatological problems in the elderly; however, current therapies for it are limited by low efficacy and undesirable side effects. Although clinical reports on fractional laser treatment for various alopecia types are increasing, the exact mechanism remains to be clarified. The purposes of this study were to demonstrate the effect of ablative fractional laser treatment on hair follicle regrowth in vivo and investigate the molecular mechanism after laser treatment.

MATERIALS AND METHODS

Ablative CO2 fractional laser was applied to the shaved dorsal skin of 7-week-old C57BL/6 mice whose hair was in the telogen stage. After 12 mice were treated at various energy (10-40 mJ/spot) and density (100-400 spots/cm(2) ) settings to determine the proper dosage for maximal effect. Six mice were then treated at the decided dosage and skin specimens were sequentially obtained by excision biopsy from the dorsal aspect of each mouse. Tissue samples were used for the immunohistochemistry and reverse transcription polymerase chain reaction assays to examine hair follicle status and their related molecules.

RESULTS

The most effective dosage was the 10 mJ/spot and 300 spots/cm(2) setting. The anagen conversion of hair was observed in the histopathological examination, while Wnt/β-catenin expression was associated with hair regrowth in the immunohistochemistry and molecular studies.

CONCLUSIONS

Ablative fractional lasers appear to be effective for inducing hair regrowth via activation of the Wnt/β-catenin pathway in vivo. Our findings indicate that fractional laser treatment can potentially be developed as new treatment options for stimulating hair regrowth.

Topically applied methotrexate is rapidly delivered into skin by fractional laser ablation

OBJECTIVES

Methotrexate (MTX) is a chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects. This study investigated kinetics and biodistribution of MTX delivered topically by ablative fractional laser (AFXL).

METHODS

In vitro passive diffusion of 10 mg/ml MTX (1 w/v%) was measured from 0.25 to 24 h through AFXL-processed and intact porcine skin in Franz Cells (n = 46). A 2,940 nm fractional Erbium Yttrium Aluminium Garnet laser generated mid-dermal microchannels at 2.4% density, and 256 mJ/microchannel. HPLC quantified MTX-concentrations in extracts from mid-dermal skin sections, donor and receiver compartments. Fluorescence microscopy of UVC-activated MTX-fluorescence and desorption electro-spray ionization mass spectrometry imaging (DESI-MSI) evaluated MTX biodistribution.

RESULTS

AFXL-processed skin facilitated rapid MTX delivery through cone-shaped microchannels of 690 µm ablation depth, lined by the 47 µm thermal coagulation zone (CZ). Quantitatively, MTX was detectable by HPLC in mid-dermis after 15 min, significantly exceeded deposition in intact skin after 1.5 h, and saturated skin after 7 h at a 10-fold increased MTX-deposition versus intact skin (3.08 vs 0.30 mg/cm(3), p = 0.002). Transdermal permeation was < 1.5% of applied MTX before skin saturation, and increased up to 8.0% after 24 h. Qualitatively, MTX distributed into CZ within 15 min (p = 0.015) and further into surrounding dermal tissue after 1.5 h (p = 0.004). After skin saturation at 7 h, MTX fluorescence intensities in CZ and tissue were similar and DESI-MSI confirmed MTX biodistribution throughout the mid-dermal skin section.

CONCLUSIONS

MTX absorbs rapidly into mid-dermis of AFXL-processed skin with minimal transdermal permeation until skin saturation, suggesting a possible alternative to systemic MTX for some skin disorders.

Microscopic and ultrastructural modifications of postmenopausal atrophic vaginal mucosa after fractional carbon dioxide laser treatment

Vaginal atrophy occurring during menopause is closely related to the dramatic decrease in ovarian estrogens due to the loss of follicular activity. Particularly, significant changes occur in the structure of the vaginal mucosa, with consequent impairment of many physiological functions. In this study, carried out on bioptic vaginal mucosa samples from postmenopausal, nonestrogenized women, we present microscopic and ultrastructural modifications of vaginal mucosa following fractional carbon dioxide (CO2) laser treatment. We observed the restoration of the vaginal thick squamous stratified epithelium with a significant storage of glycogen in the epithelial cells and a high degree of glycogen-rich shedding cells at the epithelial surface. Moreover, in the connective tissue constituting the lamina propria, active fibroblasts synthesized new components of the extracellular matrix including collagen and ground substance (extrafibrillar matrix) molecules. Differently from atrophic mucosa, newly-formed papillae of connective tissue indented in the epithelium and typical blood capillaries penetrating inside the papillae, were also observed. Our morphological findings support the effectiveness of fractional CO2 laser application for the restoration of vaginal mucosa structure and related physiological trophism. These findings clearly coupled with striking clinical relief from symptoms suffered by the patients before treatment.

Ablative fractional laser resurfacing helps treat restrictive pediatric scar contractures

Conventional management of debilitating pediatric scar contractures, including hand therapy and surgery, may often be beset by delayed treatment, suboptimal results, and additional surgical morbidity. Ablative fractional laser resurfacing is an emerging adjunctive procedural option for scar contractures because of its promising efficacy and safety profile. However, its use to improve function has not been studied in the pediatric population. Herein we report 2 pediatric patients with recalcitrant scar contractures, causing persistent functional deficits, treated with an ablative fractional laser protocol. Both patients experienced rapid and cumulative subjective and objective improvements in range of motion and function as measured by an independent occupational therapist without reported complications. We highlight ablative fractional laser resurfacing as a novel and promising tool in the management of function-limiting scar contractures in children and propose that the technique be incorporated into existing scar treatment paradigms, guided by future research.

Successful Treatment of Atrophic Facial Leishmaniasis Scars by CO2 Fractional Laser

Background:

A permanent, unpleasant atrophic leishmaniasis scar is a potentially disfiguring condition that causes social stigma with limited treatment choices. Fractionated carbon dioxide (CO2) laser resurfacing is expected to be a safe and effective treatment for leishmaniasis scars.

Objective:

To assess the safety and efficacy of ablative fractional resurfacing (AFR) with a CO2 laser for facial leishmaniasis atrophic scars.

Methods:

Eleven patients (five males, age 18–47 years) underwent the fractional CO2 laser procedure. The mean duration for scars was 18.3 years. Three to five treatment sessions with the fractional laser eCO2 (10,600 nm, Lutronic Corporation, Gyeonggi-do, Korea) were performed for each patient, at 2-month intervals, under topical anesthesia. Two passes (with tip type 120, density 150 spots/cm2 in static mode, and peak power of 30 watts) were performed on each leishmaniasis scar. Pulse energies ranged between 100 and 140 mJ. Posttreatment improvements in texture, atrophy, and overall satisfaction with appearance were graded on a quartile scale 1 month after the second session and 3 months after the final session. Scar improvement was graded using a 4-point score with a maximum score of 20.

Results:

At the 3-month posttreatment follow-up, all subjects were rated as having at least 50% improvement in texture, atrophy, borders, and overall appearance of scars. The median score of improvement was 18 of 20 (range 11–19). Mild postinflammatory hyperpigmentation was the only adverse effect, observed in 18% (2 of 11) of subjects. After the procedure, moderate to severe erythema and edema typically resolved within 24 to 48 hours. No additional adverse effects were observed.

Conclusion:

Fractional CO2 resurfacing represents a safe, effective, and well-tolerated potential treatment for atrophic facial leishmaniasis scars in ethnic skin.

In vivo non-invasive monitoring of collagen remodelling by two-photon microscopy after micro-ablative fractional laser resurfacing

Non-linear optical microscopy is becoming popular as a non-invasive in vivo imaging modality in dermatology. In this study, combined TPF and SHG microscopy were used to monitor collagen remodelling in vivo after micro-ablative fractional laser resurfacing. Papillary dermis of living subjects, covering a wide age range, was imaged immediately before and forty days after treatment. A qualitative visual examination of acquired images demonstrated an age-dependent remodelling effect on collagen. Additional quantitative analysis of new collagen production was performed by means of two image analysis methods. A higher increase in SHG to TPF ratio, corresponding to a stronger treatment effectiveness, was found in older subjects, whereas the effect was found to be negligible in young, and minimal in middle age subjects. Analysis of collagen images also showed a dependence of the treatment effectiveness with age but with controversial results. While the diagnostic potential of in vivo multiphoton microscopy has already been demonstrated for skin cancer and other skin diseases, here we first successfully explore its potential use for a non-invasive follow-up of a laser-based treatment.

Pseudoxanthoma Elasticum Treatment with Fractional CO2 Laser

SUMMARY

Pseudoxanthoma elasticum (PE) is a rare genetic disease characterized by calcification and fragmentation of elastic fibers of the skin, retina, and cardiovascular system. We report a case of PE in which fractional carbon dioxide laser treatment was successfully used to achieve improvement of the cervical skin with 2-year follow-up, in a patient with Fitzpatrick skin type IV. After the fifth session, the patient presented with a local herpes infection. The postlaser reaction of the PE skin was similar to that of the normal skin, in terms of the duration of redness, pain, swelling, and duration of crusting. The overall cosmetic result was satisfactory, with improvement in skin texture, irregularity, volume, and distensibility. The herpetic infection reinforces the value of antiviral prophylaxis during laser treatment of extrafacial areas.

Comparing the Healing Effects of Arnebia euchroma Ointment With Petrolatum on the Ulcers Caused by Fractional CO2 Laser: A Single-Blinded Clinical Trial

Background:

Arnebia euchroma ointment (AEO) has been used in Iranian traditional medicine for burn wound healing.

Objectives:

The aim of this study is to evaluate wound healing efficacy of AEO in burn wounds after fractional Co2 laser.

Patients and Methods:

This split-face, single-blinded, single-center clinical study was performed in Shohada-e-Tajrish Hospital, Tehran, Iran. A total of 26 subjects with facial acne scar, who were to receive fractional CO₂ laser resurfacing were recruited. After laser procedure, AEO was applied to one side of the face and petrolatum on the other side for wound healing. Digital photographs were taken from acne scar area before resurfacing and on each of the assessment sessions. Three researchers, who were unaware of the applied medications, assessed these digital photographs for erythema, edema, epithelial confluence, crusting/scabbing, and general wound appearance. Subject’s irritations such as dryness and itching were evaluated on the second, fifth, and seventh days.

Results:

Our study indicated higher epithelial confluence and general wound appearance scores (P = 0.045 for both) and less erythema and edema on fifth day in petrolatum (P = 0.009 and P = 0.034, respectively). The results showed less crusting and erythema (P = 0.016 and P = 0.035, respectively) and higher general wound appearance scores in petrolatum on the second day (P = 0.035 and P = 0.001, respectively). Dryness was the most common subjective complaint in both groups; however, it was more severe in AEO, especially on the second day (P = 0.023).

Conclusions:

Despite the healing effects of AEO in burn wounds, petrolatum was more effective than AEO in post-laser wound.

Fractional Erbium laser in the treatment of photoaging: randomized comparative, clinical and histopathological study of ablative (2940nm) vs. non-ablative (1540nm) methods after 3 months

BACKGROUND

Fractional non-ablative lasers keep the epidermis intact, while fractional ablative lasers remove it, making them theoretically more effective.

OBJECTIVES

To evaluate the clinical and histological alterations induced by fractional photothermolysis for treating photoaging, comparing the possible equivalence of multiple sessions of 1540nm Erbium, to one session of 2940nm Erbium.

METHODS

Eighteen patients (mean age 55.9) completed the treatment with three sessions of 1540nm fractional Erbium laser on one side of the face (50 mJ/mB, 15ms, 2 passes), and one session of 2940nm on the other side (5mJ/mB, 0.25ms, 2 passes). Biopsies were performed before and 3 months after treatment. Clinical, histological and morphometric evaluations were carried out.

RESULTS

All patients presented clinical improvement with no statistically significant difference (p> 0.05) between the treated sides. Histopathology revealed a new organization of collagen and elastic fibers, accompanied by edema, which was more evident with the 2940nm laser. This finding was confirmed by morphometry, which showed a decrease in collagen density for both treatments, with a statistical significance for the 2940nm laser (p > 0.001).

CONCLUSIONS

Three 1540nm sessions were clinically equivalent to one 2940nm session. The edema probably contributed to the positive results after three months, togheter with the new collagen and elastic fibers organization. The greater edema after the 2940nm session indicates that dermal remodeling takes longer than with 1540nm. It is possible that this histological superiority relates to a more prolonged effect, but a cohort longer than three months is needed to confirm that supposition.

Non-ablative fractional laser provides long-term improvement of mature burn scars--a randomized controlled trial with histological assessment

BACKGROUND AND OBJECTIVES

Non-ablative fractional laser-treatment is evolving for burn scars. The objective of this study was to evaluate clinical and histological long-term outcome of 1,540 nm fractional Erbium: Glass laser, targeting superficial, and deep components of mature burn scars.

MATERIALS & METHODS

Side-by-side scar-areas were randomized to untreated control or three monthly non-ablative fractional laser-treatments using superficial and extra-deep handpieces. Patient follow-up were at 1, 3, and 6 months. Primary outcome was improvement in overall scar-appearance on a modified-Patient-and-Observer-Scar-Assessment-Scale (mPOSAS, 1 = "normal skin", 10 = "worst imaginable scar"). Secondary outcomes included histology, patient satisfaction (0-10), patient-assessed improvement, and safety.

RESULTS

Study was completed by 17 of 20 randomized patients with normotrophic (n = 11), hypertrophic (n = 5) or atrophic (n = 1) scars. Scar-appearance improved from laser-treatments (P < 0.001 vs. untreated) and histology at 6 months supported collagen-remodeling. Improvement appeared continuously during the post-operative period (mPOSAS baseline: 7 [5-8], 6 months: 4 [3-5] P = < 0.001). At 6 months, patients were satisfied with treatment (6 [3-9]) and 82% reported improved scar-texture. Treatments caused mild to moderate pain (4 [2-7]). Adverse effects decreased during follow-up and at final assessment, discrete erythema, hyperpigmentation or imprints from laser-grid were present in 11 patients. No patients experienced worsening of scar-appearance.

CONCLUSIONS

Combined superficial and deep non-ablative fractional laser-treatments induce long-term clinical and histological improvement of mature burn scars.

Observation of in vivo morphologic changes after carbon dioxide ablative fractional laser in a mouse model using noninvasive imaging modalities and comparison with histologic examination

Ablative fractional carbon dioxide (CO2) lasers have been widely used for several types of cosmetic dermatosis. A number of previous studies have evaluated this technique in animals or human beings by observing morphologic changes using an invasive modality such as skin biopsy. In this study, we assessed in vivo skin changes after CO2 ablative fractional laser treatment in a mouse model using noninvasive imaging modalities (Folliscope(®) and Visioscan 98(®)), and each results was compared with data from histologic examination. An ablative fractional CO2 laser was applied with different pulse energy between 7 to 35 mJ/microspot. As results of above methods, we also confirmed that the CO2 ablative fractional laser generated injuries with increasing width and depth with increasing pulse energy. Although numerous papers have described application of this laser in vivo skin specimens, our study evaluated the feasibility of using relative noninvasive imaging modalities for assessing the outcome of laser ablation. Based on our data, we suggest that these technologies may be useful alternative modalities for assessing laser ablation that are easier to perform and less invasive than skin biopsy.

Will nonablative rejuvenation replace ablative lasers? Facts and controversies

Since the early 1980s, the field of skin rejuvenation has evolved rapidly. Traditional ablative resurfacing with carbon dioxide and Er:YAG lasers offered dramatic improvement of the skin tone and texture, but prolonged postoperative period and an increased risk for side effects and complications were unacceptable for the majority of patients. It prompted the development of nonablative lasers and non-laser systems, which stimulate dermal neocollagenesis without epidermal disruption, and therefore, produce less adverse effects with little or no healing time. Recently, fractional nonablative and ablative lasers have been introduced, employing a completely new concept of fractional photothermolysis, which ensures high efficacy and fewer risks. Ablative laser resurfacing still remains the gold standard for treating advanced and severe photoaging providing excellent results in experienced hands. Alternatively, ablative fractional resurfacing can be used, with the results, which are comparable to fully ablative lasers with better standard of safety. Nonablative resurfacing is ideal for patients under the age of 50 years with minimal facial sagging, and for those who are unwilling to undergo expensive and demanding ablative procedures. It can be concluded that the key of therapeutic success is in proper patient selection, setting appropriate expectations and combining different rejuvenation technologies with other therapeutic modalities, such as botulinum toxin and fillers.

Nd:YAG laser for "fractional" treatment of angiofibromas

BACKGROUND

Tuberous sclerosis is an autosomal dominant disorder with hamartomas in multiple organ systems. Facial angiofibromas (AF) are a common cutaneous manifestation of tuberous sclerosis. They may lead to significant cosmetic and psychological problems. Many treatment modalities have been used with variable satisfaction. Fractional photothermolysis (FP) is a novel concept of laser therapy, which induces non-contiguous microscopic thermal injury.

OBJECTIVE

This study was designed to evaluate the efficacy and side effects of Nd:YAG laser treatment for facial AF by using spot-like irradiation technique similar to FP.

MATERIALS AND METHODS

Twelve patients (skin types III-IV, aged 17-45 years) with facial AF received monthly treatment with Nd:YAG laser in a pinpoint coagulation fashion. Clinical improvements were evaluated in five categories. Side effects were monitored at each follow-up visit.

RESULTS

Excellent improvement was seen in 10 patients and good improvement in two at one month after the final treatment session. After 12 months of follow-up, no patient had significant recurrence of AF. Five patients were followed up for three years with few pinpoint-sized regrowth occurring; none of these patients received additional treatments. Side effects included transient erythema and edema in each patient but no bleeding, infection, dyspigmentation, or scarring.

CONCLUSIONS

The present study indicates that Nd:YAG laser is an effective and safe management for the fractional treatment of facial AF.

Lasers as an approach for promoting drug delivery via skin

INTRODUCTION

Using lasers can be an effective drug permeation-enhancement approach for facilitating drug delivery into or across the skin. The controlled disruption and ablation of the stratum corneum (SC), the predominant barrier for drug delivery, is achieved by the use of lasers. The possible mechanisms of laser-assisted drug permeation are the direct ablation of the skin barrier, optical breakdown by a photomechanical wave and a photothermal effect. It has been demonstrated that ablative approaches for enhancing drug transport provide some advantages, including increased bioavailability, fast treatment time, quick recovery of SC integrity and the fact that skin surface contact is not needed. In recent years, the concept of using laser techniques to treat the skin has attracted increasing attention.

AREAS COVERED

This review describes recent developments in using nonablative and ablative lasers for drug absorption enhancement. This review systematically introduces the concepts and enhancement mechanisms of lasers, highlighting the potential of this technique for greatly increasing drug absorption via the skin. Lasers with different wavelengths and types are employed to increase drug permeation. These include the ruby laser, the erbium:yttrium-gallium-garnet laser, the neodymium-doped yttrium-aluminum-garnet laser and the CO2 laser. Fractional modality is a novel concept for promoting topical/transdermal drug delivery. The laser is useful in enhancing the permeation of a wide variety of permeants, such as small-molecule drugs, macromolecules and nanoparticles.

EXPERT OPINION

This potential use of the laser affords a new treatment for topical/transdermal application with significant efficacy. Further studies using a large group of humans or patients are needed to confirm and clarify the findings in animal studies. Although the laser fluence or output energy used for enhancing drug absorption is much lower than for treatment of skin disorders and rejuvenation, the safety of using lasers is still an issue. Caution should be used in optimizing the feasible conditions of the lasers in balancing the effectiveness of permeation enhancement and skin damage.

Laser fractional photothermolysis of the skin: numerical simulation of microthermal zones

BACKGROUND

Laser Fractional Photothermolysis (FP) is one of the innovative techniques for skin remodeling and resurfacing. During treatment, the control of the Microscopic Thermal Zones' (MTZs) dimensions versus pulse energy requires detailed knowledge of the various parameters governing the heat transfer process. In this study, a mathematical model is devised to simulate the effect of pulse energy variations on the dimensions of MTZs.

METHODS

Two series of simulations for ablative (10.6 μm CO2) and non-ablative (1.550 μm Er:Glass) lasers systems were performed. In each series, simulations were carried for the following pulses energies: 5, 10, 15, 20, 25, 30, 35, and 40 mJ. Results of simulations are validated by histological analysis images of MTZs sections reported in works by Hantash et al. and Bedi et al.

RESULTS

MTZs dimensions were compared between histology and those achieved using our simulation model using fusion data technique for both ablative FP and non-ablative FP treatment methods. Depths and widths from simulations are usually deeper (21 ± 2%) and wider (12 ± 2%) when compared with histological analysis data.

CONCLUSION

When accounting for the shrinkage effect of excision of cutaneous tissues, a good correlation can be established between the simulation and the histological analysis results.

Residual scarring from hidradenitis suppurativa: fractionated CO2 laser as a novel and noninvasive approach

Hidradenitis suppurativa (HS) is a chronic, relapsing, inflammatory skin condition that can have a significant psychosocial impact, both with the active disease and with residual scarring. Although a wide variety of treatment options exist for HS, to our knowledge there are no reported modalities aimed specifically at treating HS scarring. We describe the case of an adolescent female who received medical management of intramammary HS followed by successful treatment with fractionated 10,600-nm carbon dioxide laser for her residual cribriform scarring. We believe there is great potential for the use of fractionated carbon dioxide laser to improve short- and long-term psychosocial outcomes of HS, promote physical scar remodeling, and possibly alter the disease process itself.

Treatment of acne scars and wrinkles in asian patients using carbon-dioxide fractional laser resurfacing: its effects on skin biophysical profiles

Background

Although ablative fractional resurfacing is known to be effective against photoaging and acne scars, studies on its efficacy, safety and changes in the skin characteristics of Asians are limited.

Objective

The aim of this study is to assess the efficacy and safety of carbon dioxide fractional laser (CO₂FL) in Koreans treated for wrinkles and acne scars, and to define the changes in skin characteristics during recovery period.

Methods

We administered one session of CO₂FL on 10 acne scar patients and 14 wrinkles patients with skin types IV and V. The surveillance of efficacy and side effects along with the measurement of biophysical properties was carried out before 1 day, 1 week, 1 month and 3 months after treatment.

Results

Using a non-invasive method, skin barrier damage, erythema and bronzing of skin during the recovery period were assessed, and all of the items eventually returned to the pre-treatment level. Skin elasticity was measured in the wrinkle group, and the statistically significant effect was sustained throughout the next three months. The outcome of treatment was found to be better than 'moderate improvement' in both the acne scar and wrinkle groups. Further, there were no serious side effects three months post-procedure.

Conclusion

CO₂ FL is thought to be an effective and safe method for treating moderate to severe acne scars and wrinkles in Asians.

Treatment of split-thickness skin graft-related forearm scar contractures with a carbon dioxide laser protocol: 3 case reports

Split-thickness skin grafts in the forearm can lead to motion restriction and disability through the dense scarring of the skin and formation of graft-tendon adhesions. Three patients were referred for laser treatment of motion-limiting scar-associated split-thickness skin grafts to the forearm. All patients had reached a plateau in range of motion despite aggressive hand therapy and underwent serial laser scar treatments at 6- to 8-week intervals. Treatments were performed in a clinic setting and were initiated 2 to 5 months after reconstructive surgery. Rapid subjective functional and objective improvements in range of motion were noted after laser therapy. Results were cumulative and durable at final follow-up ranging from 10 to 15 months after the initial treatment. No complications were noted. Fractionated carbon dioxide laser therapy is a promising adjunct to hand therapy when the main restraint to motion is superficial skin scarring and skin-tendon adhesions.

Fractionated ablative carbon dioxide laser for the treatment of rhinophyma

BACKGROUND

Rhinophyma is a progressive and disfiguring proliferative disorder of the nose, which is related to chronic rosacea. Many different treatment modalities have been utilized both alone and in combination including: loop cautery, CO2 laser, argon laser, dermabrasion, cryotherapy, radiotherapy, full-thickness excision, skin graft, flap reconstruction, and cold scalpel. CO2 resurfacing has been considered first line therapy but is often associated with a shiny, scarred appearance, with patulous pores, and with loss of pigmentation. We report a technique using aggressive parameters with the fractionated ablative CO2 laser, resulting in improvement of appearance with very few complications.

MATERIALS AND METHODS

Five patients who presented with rhinophyma of varying degrees were treated with a series of fractional ablative CO2 laser treatments (Fraxel re:Pair, Solta Medical, Hayward, CA). These patients were treated with settings of up to 70 mJ, 70% density and 16-18 passes. All patients received HSV prophylaxis using either acyclovir 400 mg TID or valacyclovir 500 mg BID. Patients were rendered anesthetic by 1% lidocaine and epinephrine regional perinasal nerve block.

RESULTS

All of the patients tolerated the procedure well with reepithelialization at days 4-7 and self-limited edema and erythema. Patients with relatively early to moderate signs of rhinophyma proved optimal candidates for this treatment. There were no adverse events. Patients and physicians noted significant improvement and reduction in the rhinophyma without the typical scarring noted with most other treatments.

CONCLUSION

Rhinophyma treated with fractionated ablative CO2 laser using relatively aggressive parameters achieved good cosmetic outcomes in this group of early to moderate cases of rhinophyma, while still retaining the benefits of a fractionated treatment such as faster healing times and fewer adverse events.