点阵激光改善皮肤光老化作用机制的研究进展

点阵激光已广泛用于治疗各种皮肤疾病,包括皮肤光老化、痤疮瘢痕和色素性疾病等,其利用点阵光热分解的原理,点阵激光作用皮肤后形成微治疗区,周围仍见正常组织,角质形成细胞快速从周围迁移、增殖和上皮化,从而促进快速愈合,停工期短。主要概述点阵激光改善皮肤光老化的研究进展,从组织学改变和分子水平作用机制进行阐述。     

Nonablative fractional resurfacing in the male patient

ABSTRACT:  Skin resurfacing can be divided into nonablative, nonablative fractional, ablative fractional, and traditional ablative categories. Nonablative technologies have yielded inconsistent and unimpressive results, whereas ablative technologies, although generally clinically effective, are losing momentum as a result of prolonged recovery times, risks for hypopigmentation, limitation in lighter skin types, and the production of unnatural sheen and texture to the skin. Fractional resurfacing can produce the safety of nonablative technologies and the efficacy of traditional ablative resurfacing. Nonablative fractional resurfacing is the most widely studied of fractional technologies allowing for nonablative tissue coagulation, creation of microthermal zones, and resurfacing with extrusion and replacement of damaged tissue with rapid re-epithelialization. This article will review nonablative fractional resurfacing with 1550-nm laser in the male patient.     

Nonablative fractional laser resurfacing in Asian skin--a review

Skin resurfacing has been a part of cosmetic dermatology for more than two decades now, and most of it has been ablative with traditional aggressive lasers including the CO(2) and erbium. The last few years have seen a revolutionary change with the invention of nonablative lasers for skin tightening. Fractional resurfacing is a new concept of cutaneous remodeling whereby laser-induced zones of microthermal injury are surrounded by normal untreated tissue that helps in quicker healing. The various wavelengths used are 1320, 1440, and 2940 nm with depth of penetration ranging from 25 μ to 1.2 mm. This article reviews the history of nonablative fractional laser resurfacing, its indications, contraindications, and a review of use in Asian skin with Fitzpatrick type III-VI.     

A study of fractional CO₂ laser resurfacing: the best fluences through a clinical, histological, and ultrastructural evaluation

Background Fractional resurfacing is a laser treatment modality to create numerous microscopic thermal injury zones of controlled width, depth, and density that are surrounded by a reservoir of spared epidermal and dermal tissue, allowing rapid repair of laser‐induced thermal injury. Objective To evaluate the safety and efficacy of a fractional CO₂ laser system in the treatment of photo‐damaged skin with clinical, histological, and ultrastructural evaluation, with special attention to one of the parameters of this laser system: the fluences. Materials and methods Twelve patients with Fitzpatrick skin types II to III with photo‐damage skin underwent fractional laser treatment with one single‐pass superficial on the face and forearm. Clinical outcome and histological and ultrastructural changes were assessed. Results  Light microscopy of biopsies gave important information about skin changes at three different times after fractional treatment, especially revealing some differences between the fluences used in the three groups of patients. Conclusion Fractional resurfacing offers significant surgical advantages allowing to achieve excellent esthetic results in balance with the biological structure. Besides, our study shows already that with 2.07 and 2.77 J/cm², instead of 4.15 J/cm², it is possible to reach a biological response without scar formation.     

The spectrum of laser skin resurfacing: nonablative, fractional, and ablative laser resurfacing

The drive to attain cosmetic facial enhancement with minimal risk and rapid recovery has inspired the field of nonsurgical skin rejuvenation. Laser resurfacing was introduced in the 1980s with continuous wave carbon dioxide (CO(2)) lasers; however, because of a high rate of side effects, including scarring, short-pulse, high-peak power, and rapidly scanned, focused-beam CO(2) lasers and normal-mode erbium-doped yttrium aluminium garnet lasers were developed, which remove skin in a precisely controlled manner. The prolonged 2-week recovery time and small but significant complication risk prompted the development of non-ablative and, more recently, fractional resurfacing in order to minimize risk and shorten recovery times. Nonablative resurfacing produces dermal thermal injury to improve rhytides and photodamage while preserving the epidermis. Fractional resurfacing thermally ablates microscopic columns of epidermal and dermal tissue in regularly spaced arrays over a fraction of the skin surface. This intermediate approach increases efficacy as compared to nonablative resurfacing, but with faster recovery as compared to ablative resurfacing. Neither nonablative nor fractional resurfacing produces results comparable to ablative laser skin resurfacing, but both have become much more popular than the latter because the risks of treatment are limited in the face of acceptable improvement. LEARNING OBJECTIVES: At the completion of this learning activity, participants should be familiar with the spectrum of lasers and light technologies available for skin resurfacing, published studies of safety and efficacy, indications, methodologies, side effects, complications, and management.     

Skin rejuvenation with microthermal fractional photothermolysis

ABSTRACT:  Fractional resurfacing is gaining acceptance as a preferred method for skin resurfacing. Experience in treating photoaging, acne scars, and melasma is reviewed.     

Severe neck scarring: A consequence of fractional CO2 laser resurfacing

Fractional CO₂ laser resurfacing using aggressive treatment parameters may result in adverse effects comparable to those of fully ablative CO₂ laser resurfacing. A 45-year-old female underwent fractional CO₂ laser treatment of the neck. She contacted the author for treatment of the marked erythema, swelling, and perceived skin tightness that resulted from the resurfacing procedure. This case report describes how the author treated these complications, provides a plausible explanation for why they occurred, and recommends treatment modifications to minimize the risk of their occurrence.     

Fractional CO2 laser treatment for a skin graft

Skin grafts are widely used in reconstructive and plastic surgery, leaving an inevitable scar appearance on the body, affecting the quality of life of the patients. Fractional ablative lasers have become a leading procedure for the treatment of acne and burn scars. We report a case of a skin graft showing excellent improvement in overall appearance after three sessions of fractional CO₂ laser. The undamaged tissue left between the microthermal treatment zones is responsible of collagen formation and reepithelialization. Remodeling and collagen formation are observed even 6 months after a fractional CO₂ laser session.     

A study of multiple full-face treatments with low-energy settings of a 2940-nm Er:YAG fractionated laser

Abstract

Background and objective: Fractional Er:YAG 2940-nm laser resurfacing is a relatively new approach to the treatment of photodamaged skin. Typically, this approach uses fairly high delivered energies in order to create ‘microscopic wounds’ of tissue coagulation at various dermal depths. The purpose of this study was to evaluate the efficacy, safety and tolerability of low-energy, multiple-treatment, fractional Er:YAG laser resurfacing for the treatment of photoaged skin. Methods: Sixteen subjects with photoaged skin received six, lower-fluence laser treatments with a 2940-nm wavelength Er:YAG laser, using a fractionated handpiece and a maximum energy of 30 mJ per micro-spot. Subject satisfaction, treatment tolerability, and subject outcome assessment were performed. Results: Of the 12 subjects who completed the trial, all recorded improvement in their treated skin; half reported over 50% improvement. Most patients reported none or only mild stinging and burning during and after treatment. There was no downtime associated with the procedure. No adverse events were reported. Patient satisfaction rates were high. Conclusion: Low-energy, multiple treatment, 2940-nm Er:YAG laser resurfacing with this novel device is a safe and well-tolerated method for the treatment of superficial to moderate photoaged skin.     

Utilizing fractional resurfacing in the treatment of therapy-resistant melasma.

BACKGROUND: Multiple treatment modalities have been employed for the management of melasma with minimal to no success. OBJECTIVE: We propose fractional resurfacing as a new treatment modality for melasma. METHODS: A 31-year-old Caucasian female with facial epidermal and dermal melasma, resistant to multiple courses of topical therapies, was treated with two sessions of full-face fractional resurfacing (Fraxel(TM) Laser; Reliant technologies, San Diego, CA), separated by a three-week interval. Clinical improvement was assessed by Wood's Lamp examination as well as parallel and cross-polarized comparative photography at baseline and 6 months later. RESULTS: Marked reduction in epidermal and dermal facial pigmentation was observed at the six-month follow-up visit. CONCLUSION: Fractional resurfacing may prove to be an effective and safe treatment modality for lightening of the epidermal and dermal pigmentation of melasma. Further studies with long-term follow-up periods and multiple patients with diverse skin phototypes and different variants of melasma are warranted.     

Lasers in skin resurfacing

The development of short-pulse high-peak power and rapidly scanned focused beam carbon dioxide lasers and normal mode erbium:yttrium aluminum garnet lasers, which can remove photodamaged skin layer by layer in a precisely controlled manner while leaving behind a very narrow zone of thermal damage, has revolutionized skin rejuvenation and enhanced our ability to treat scars. This review highlights laser-tissue interactions; the laser used for resurfacing; preoperative, operative, and postoperative issues and how to choose a candidate for the procedure; uses of resurfacing; adverse effects and complications of the procedure; and new developments in the field.     

Combined use of fractional CO2 laser and radiofrequency waves to treat acne scars: a pilot study on 15 patients

Fractional laser resurfacing has become an important technique in the management of a number of skin conditions, such as photoaging and scars. A variety of laser wavelengths and delivery systems have been introduced to improve immediate and long-term therapeutic results. The simultaneous emission of CO(2) laser and radiofrequency waves combines epidermal coagulation for a resurfacing effect and dermal denaturization for deeper remodelling. The authors present this new machine together with a preclinical histological study and pilot study on 15 patients suffering from acne scars.     

Skin Characteristics after Fractional Photothermolysis

Background

Fractional photothermolysis makes thousands of minute areas called microthermal treatment zones on the skin surface and transmits thermal injury to facilitate heat shock protein formation around the dermis. Potential side effects include acneiform eruption, herpes simplex virus outbreak, erythema, and post-inflammatory hyperpigmentation.

Objective

To investigate and compare the changes in the skin of Asian patients after two different fractional photothermolysis systems (FPS) on a split face.

Methods

A half-split face study was performed with 10,600 nm carbon dioxide FPS on the left and 1,550 nm erbium-doped FPS on the right side of the face. Only one session of laser irradiation and several biophysical measurements were done.

Results

Although both FPS proved to be effective in treating acne scar and wrinkle patients, a slightly higher satisfaction rating was seen with the 10,600 nm FPS treatment. Both types of FPS showed a significant increase in transepidermal water loss which decreased gradually after treatment and returned to pre-treatment level after 1 week. A decreased reviscometer score was sustained for a longer period in wrinkle areas treated with 10,600 nm FPS.

Conclusion

Even though the changes in skin varied according to different FPS wave-length, adverse outcomes, such as increased erythema and TEWL were entirely subdued within 3 months of treatment.     

Role of Erbium:YAG laser in the treatment of aged skin

Laser resurfacing procedures in actinic skin damage and the treatment of disorders associated with skin ageing are becoming more popular. For both purposes Erbium:YAG laser-technology enables us to perform a highly precise skin ablative work, which can be most helpful in the removal of circumscribed skin lesions of ageing skin as well as in larger skin resurfacing procedures. In most circumstances, superficial skin ablation is not technically demanding, is not associated with major discomfort, and can be controlled with precision. Tissue sparing ablation is of special value in the treatment of disorders in atrophic skin of elderly patients or in more delicate areas, where it can avoid prolonged healing and unwarranted side-effects.     

Fractional ablative laser skin resurfacing: a review

Ablative laser technology has been in use for many years now. The large side effect profile however has limited its use. Fractional ablative technology is a newer development which combines a lesser side effect profile along with similar efficacy. In this paper we review fractional ablative laser skin resurfacing.     

Micro-island damage with a nonablative 1540-nm Er:Glass fractional laser device in human skin

Background and objectives  Fractional photothermolysis produces micro-islands of thermal injury to the skin while preserving areas among treated tissue sites in order to promote wound healing. Histological changes associated with single and multiple passes of the 1540-nm Er:Glass fractional laser were examined using in vivo human skin.
Methods and materials  Panni of five abdominoplasty patients were treated intraoperatively with a Fractional Lux1540 erbium glass laser system at various laser parameters, with single and multiple passes. Biopsies were removed and examined using standard histological stains.
Results  Deep coagulated columns of collagen separated by regions of unaffected tissue were observed at variable fluence parameters. A direct correlation between the depth of penetration of the coagulated microcolumns and increasing energies was observed. Micro-islands of coagulation were ∼250 μm in diameter and separated by ∼800 μm of unaffected tissue. With multiple passes, significantly more disruption of the dermal–epidermal junction (DEJ) occurred at higher fluences. In contrast to the controlled fractional columns observed with single-pass treatments, nonuniform coagulated columns were distributed randomly throughout the tissue when instituting multiple passes over the same treatment region.
Conclusion  Micro-islands of thermal damage were observed at variable energy parameters. Pathological changes within the skin were clearly dependent on amount of energy and number of passes of the laser treatment. Significantly more superficial damage, accompanied by disruption of the DEJ was observed with multiple passes when compared with single pass at similar fluences. However, with multiple passes, depth of thermal injury did not increase with increasing energies but did disrupt the micro-island array observed with single-pass fractional treatments.     

Combined use of fractional CO2 laser and radiofrequency waves to treat acne scars: A pilot study on 15 patients

Abstract

Fractional laser resurfacing has become an important technique in the management of a number of skin conditions, such as photoaging and scars. A variety of laser wavelengths and delivery systems have been introduced to improve immediate and long-term therapeutic results. The simultaneous emission of CO₂ laser and radiofrequency waves combines epidermal coagulation for a resurfacing effect and dermal denaturization for deeper remodelling. The authors present this new machine together with a preclinical histological study and pilot study on 15 patients suffering from acne scars.     

A novel explanation for the healing effect of the Er:YAG laser during skin rejuvenation

Abstract

The popularity of cutaneous laser resurfacing has soared in recent years. Ablative laser skin rejuvenation with carbon dioxide (CO₂) and erbium:yttrium-aluminum-garnet (Er:YAG) lasers has been popularized and their side effects individually reported. It has been suggested that initial collagen contraction and thermal damage modulate wound healing. Progress in laser technology permits precise tissue removal and minimal thermal damage. However, mechanisms for cosmetic improvement have not yet been completely determined. In the present short communication, we would like to suggest a possible mechanism for the healing effects exerted by the Er:YAG laser.     

Fractional photothermolysis

Fractional photothermolysis (FP) has been recently introduced as a new concept in dermatologic laser medicine. FP employs an array of small laser beams to create many microscopic areas of thermal necrosis within the skin called microscopic treatment zones (MTZ). Even though FP completely destroys the epidermis and dermis within these MTZ, the 3-dimensional pattern of damage heals quickly and with few side effects. FP is currently used to treat fine wrinkles, photodamaged skin, acne scars, and melasma. Due to its clinical efficacy and limited side effects FP has established itself in the past two years as an alternative treatment modality to the conventional ablative and non ablative laser therapy.     

Fraktionierte Photothermolyse

Fractional photothermolysis (FP) has been recently introduced as a new concept in dermatologic laser medicine. FP employs an array of small laser beams to create many microscopic areas of thermal necrosis within the skin called microscopic treatment zones (MTZ). Even though FP completely destroys the epidermis and dermis within these MTZ, the 3-dimensional pattern of damage heals quickly and with few side effects. FP is currently used to treat fine wrinkles, photodamaged skin, acne scars, and melasma. Due to its clinical efficacy and limited side effects FP has established itself in the past two years as an alternative treatment modality to the conventional ablative and non ablative laser therapy.