Masers to magic bullets: an updated history of lasers in dermatology

Generic outcome set for the international registry on Laser trEAtments in Dermatology (LEAD): a protocol for a Delphi study to achieve consensus on what to measure

INTRODUCTION

While laser technology has expanded the armamentarium of treatment for various skin diseases during the past years, heterogeneity in study outcomes hampers comparability and appropriate evidence synthesis. Part of these issues can be addressed by developing a generic outcome set. Using the Delphi method, this study aims to seek consensus between key stakeholders on relevant generic outcomes (what to measure) for implementation in the international registry on Laser trEAtments in Dermatology (LEAD). The registry is focused on collecting research data on various laser treatments for skin disorders.

METHODS AND ANALYSIS

By reviewing the literature and involvement of key stakeholder groups and adult patients in need or after laser surgery and health professionals, a preliminary list of outcomes will be generated and categorised into domains. Using these outcomes, an international three-round Delphi study will be performed to rate the importance of outcomes in the selection of a generic outcome set. Participants are allowed to provide new outcomes to the preliminary list for revisions during the first Delphi round. Finally, results will be discussed during a consensus meeting to agree on generic outcomes to be used in the LEAD registry.

ETHICS AND DISSEMINATION

An ethics approval was not applicable (W19_290 # 18.336). The study is registered with the Cochrane Skin Core OUtcome Set INitiative) and the Core Outcome Measures in Effectiveness Trials initiative. Procedures will be conducted according to the Declaration of Helsinki. The findings will be disseminated through peer-reviewed publications and conference presentations.

Topical anesthetics for pediatric laser treatment

Topical anesthetic agent causes transient insensibility to pain in a limited area of skin, and provides effective anesthesia in a short onset time, short duration, with seldom local or systemic side effects on intact skin and is simple to use. Topical formulations may offer significant benefits for prevention of procedural pain. Currently, they are considered to be the most effective anesthesia for laser treatments. Unfortunately, there is no standard anesthetic technique for this procedure. Lasers are being widely used in numerous dermatological and esthetics treatments in childhood. The advancement of new knowledge in laser technology have contributed to the development of new lasers that are commonly used in a pediatric population, such as Pulsed Dye, Carbon-dioxide and Nd:YAG laser. The most commonly used topical anesthetics in young patients for minimally or moderately painful laser cutaneous procedures are Lidocaine, Prilocaine, Tetracaine gel and combinations thereof.

A systematic review of outcome reporting in laser treatments for dermatological diseases

The standardization of outcome reporting is crucial for interpretation and comparison of studies related to laser treatment of skin disorders. In collaboration with the Cochrane Skin-Core Outcome Set Initiative (CS-COUSIN), a procedure has been proposed to find consensus on the most important generic outcome domains (what to measure) for implementation in the international Laser TrEAtment in Dermatology (LEAD) registry. As the first step in the development of a generic outcome set for the LEAD registry, we undertook a systematic review to identify outcomes, outcome measurement instruments, methods and definitions reported in recently published literature of laser treatments for skin disorders. A systematic search was conducted and generated a total of 707 papers. We assessed 150 studies including all types of studies involving laser treatments for the skin. Two researchers independently extracted the type, definition and frequency of all outcomes and used outcome measurement instruments. We identified 105 verbatim outcomes that were categorized into eight domains recommended by the COMET framework: appearance, long-term effects, physician and patient-reported physical signs, satisfaction, health-related quality of life, psychological functioning and adverse events. Heterogeneity in outcome reporting (e.g. categories and outcome measurement instruments) was high, and definitions were insufficiently reported. There was a clear under representation of life impact domains, including satisfaction (23%) quality of life (3%) and psychological functioning (1%). Outcome reporting concerning laser treatments for the skin is heterogeneous. Standardized outcomes are needed for improving evidence synthesis. Results of this review will be used in the next step to reach consensus between stakeholders on the outcome domains to be implemented in the LEAD registry.

Q-switched 1064 nm Nd-Yag nanosecond laser effects on skin barrier function and on molecular rejuvenation markers in keratinocyte-fibroblasts interaction

Skin represents an interface between internal and external environment; it protects human body by regulating the water loss and the maintenance of body temperature, defending against irritant and pathogen agents, and against physical, chemical, and UV damage. It provides to essential physiological functions, such as the important antioxidant defense capacity; its protective/defensive function is performed by a high number of proteins, and shows important functions in maintenance of skin barrier homeostasis. Keratinocytes and fibroblasts play a pivotal role to determine or prevent skin aging in response to intrinsic or extrinsic stimuli, modulating cytokines and several biochemical factors. Non-ablative technologies are playing an increasing role in the management of skin aging, inducing a dermal remodeling without a visible epidermal damage. The objective of this study was to evaluate the effect of Q-switched 1064 Nd-YAG laser (Medlite Conbio C6 Nd-YAG laser, Cynosure USA) in skin barrier function, analyzing the constituents which are strongly altered in aging skin. Particularly, we evaluated the expression of filaggrin, TGase, HSP70, and aquaporins, on HaCaT cells. The expression of proinflammatory cytokines has been investigated too.As a second step of the study, we analyzed the modulation of the rejuvenation molecular markers on human skin fibroblasts (HDFs) stimulated with keratinocytes conditioned medium (KCM).Our results demonstrated that Q-switched 1064 nm Nd:YAG laser acts on the skin barrier function, increasing the expression of aquaporins, filaggrin, TGase, and HSP70, modulating the proinflammatory cytokines. In fibroblasts stimulated with keratinocytes conditioned medium (KCM) and irradiated with Q-switched 1064 nm Nd:YAG laser, we can observe a reduction of MMP-1 and an increase in procollagen, collagen type I, and elastin. Our results highlight that Q-switched 1064 nm Nd:YAG laser treatment could represent an effective weapon to fight skin aging.

Comparison of the Effectiveness of Ablative and Non-Ablative Fractional Laser Treatments for Early Stage Thyroidectomy Scars

Background

Open thyroidectomy is conventionally performed at the anterior side of neck, which is a body part with a comparatively great degree of open exposure; due to this, postoperative scarring may cause distress in patients. We aimed to compare the effects of ablative and nonablative fractional laser treatments on thyroidectomy scars. We examined medical records in a retrospective manner and analyzed scars based on their digital images by using the modified Manchester Scar Scale (mMSS).

Methods

Between February 2012 and May 2013, 55 patients with thyroidectomy scars were treated with ablative (34 patients) or nonablative (21 patients) fractional laser. Each patient underwent 4 laser treatment sessions in 3–4 week intervals, 1–2 months postoperatively. Scar improvement was assessed using patient images and the mMSS scale.

Results

The mean decrease in scar score was 3.91 and 3.47 in the ablative and nonablative groups, respectively; the reduction between 2 groups did not exhibit any significant difference (P=0.16). We used the scale once again to individually evaluate scar attributes. The nonablative group accounted for a considerably higher color score value (P=0.03); the ablative group accounted for a considerably higher contour score value (P<0.01). Patient satisfaction was high and no complications occurred.

Conclusions

Both types of fractional laser treatments can be used successfully for thyroidectomy scar treatment with minimal complications; however, results indicate that higher effectiveness may be obtained from the use of ablative and nonablative lasers for hypertrophic scars and early erythematous scars, respectively. Therefore, the appropriate laser for scar treatment should be selected according to its specific characteristics.

Laser-induced capillary leakage for blood biomarker detection and vaccine delivery via the skin

Circulation system is the center for coordination and communication of all organs in our body. Examination of any change in its analytes or delivery of therapeutic drugs into the system consists of important medical practice in today's medicine. Two recent studies prove that brief illumination of skin with a low powered laser, at wavelengths preferentially absorbed by hemoglobin, increases the amount of circulating biomarkers in the epidermis and upper dermis by more than 1,000-fold. When probe-coated microneedle arrays are applied into laser-treated skin, plasma blood biomarkers can be reliably, accurately, and sufficiently quantified in 15∼30 min assays, with a maximal detection in one hr in a manner independent of penetration depth or a molecular mass of the biomarker. Moreover, the laser treatment permits a high efficient delivery of radiation-attenuated malarial sporozoites (RAS) into the circulation, leading to robust immunity against malaria infections, whereas similar immunization at sham-treated skin elicits poor immune responses. Thus this technology can potentially instruct designs of small, portable devices for onsite, in mobile clinics, or at home for point-of-care diagnosis and drug/vaccine delivery via the skin. Laser-induced capillary leakage (a) to induce extravasation of circualing molecules only (b) or facilitate entry of attenuated malaria sporozoites into the capillary (c). Skin illumination with a laser preferably absorbed by hemoglobin causes dilation of the capillary beneath the skin. The extravasated molecules can be sufficiently measured in the skin or guide sporozoites to enter the vessel.

Photoaging and the clinical utility of fractional laser

The description of atomic structure by Niels Bohr set the basis for the emergence of quantum physics. Based on these fundamentals, Einstein published in 1917 a paper on the amplification of energy by Stimulated Emission of Radiation as part of his quantum theories. In 1955, Townes and Gordon turned Einstein’s theories into practice, creating a coherent and amplified microwave device using ammonia gas in an optical medium. But it was at the beginning of the 1980s, that Anderson and Parrish published an article about the selective photothermolysis model which revolutionized clinical practice. The use of laser in photoaging began with CO₂ (10,600 nm). In 1989, it was first used for resurfacing of a face with prominent photoaging. Ablative lasers have therefore had great popularity in the 1980s and 1990s, but prolonged postoperative time and significant risk of side effects have lowered the acceptance by patients. In 2004, the description of the fractionated radiation for the treatment of photoaging, by Mainstein, represented a great event. The stimulation of collagen occurred through fractional laser beams, which would reach the selected area while saving islands of sound skin. These islands accelerated the process of cicatrization of the treated tissue and shortened the postprocedure time. Furthermore, the fractionated radiation presented a smaller range of side effects, increasing the safety of the procedure. As mentioned earlier, as fractional lasers incise on the skin, they leave islands of healthy skin that accelerate recovery, while generating necrosis columns. Such necrosis columns remove damaged extracellular matrix material, allowing resettlement of fibroblasts. Such resettled fibroblasts, under the influence of a new tensile strength, restart to produce structures for extracellular matrix, such as collagen, elastin, and proteoglycans, in a more physiological way. Fractional lasers are considered by many dermatologists as the best choice in laser therapy for the treatment of photoaging.

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.

Luminous fabric devices for wearable low-level light therapy

In this paper, a flexible luminous fabric device was developed and investigated for wearable three-dimensionally fitted low-level light therapy. The fabric device exhibited excellent optical and thermal properties. Its optical power density and operating temperature were stable during usage for 10 hours. In vitro experiments demonstrated a significant increase in collagen production in human fibroblast irradiated by the fabric device, compared with the fibroblast without light irradiation. A series of tests were conducted for the safety of the fabric for human skin contact according to ISO standard ISO 10993-1:2003. The results showed that there was no potential hazard when the luminous fabrics were in direct contact with human skin.

Misconceptions about laser treatment among dermatology patients

BACKGROUND

The use of lasers is very common in dermatology; however, many patients fear it and have various misconceptions about it. A literature search failed to show any studies on this topic.

OBJECTIVE

To explore the various misconceptions of patients about lasers in dermatology.

METHODS

A self-administered questionnaire containing 21 questions about laser use in dermatology was distributed randomly to patients attending the dermatology clinic at King Khalid University Hospital in Riyadh, Saudi Arabia, from February to April 2009.

RESULTS

The response rate was 79.3%, with 714 of the 900 distributed questionnaires being returned; the individuals sampled included 348 men (48.73%). When asked about the nature of laser, 40% (279 of 698) reported that they did not know. About 36% (251 of 698) knew it was radiation of stimulated light amplification, while 10.2% (71 of 698) reported it to be nuclear radiation. Among study participants, 51.5% (364 of 707) believed that laser was harmful to children, while 51.1% (357 of 699) believed it was unsafe during pregnancy, and 21.4% (146 of 683) thought it could cause skin cancer. Laser was believed to treat most skin diseases by 47.7% (330 of 692) of those interviewed, among whom 24.1% said that they would not accept laser treatment if it was suggested to them by a dermatologist. A stance against laser (16.3%) was most common among men (P<0.001), the illiterate (P=0.006), and those with lower education (P=0.001).

CONCLUSION

Various misconceptions about laser treatment among patients are prevalent, especially among less educated individuals. Educating the community about laser could solve this problem.

Photodynamic therapy for localized infections--state of the art

Photodynamic therapy (PDT) was discovered over 100 years ago by observing the killing of microorganisms when harmless dyes and visible light were combined in vitro. Since then it has primarily been developed as a treatment for cancer, ophthalmologic disorders and in dermatology. However, in recent years interest in the antimicrobial effects of PDT has revived and it has been proposed as a therapy for a large variety of localized infections. This revival of interest has largely been driven by the inexorable increase in drug resistance among many classes of pathogen. Advantages of PDT include equal killing effectiveness regardless of antibiotic resistance, and a lack of induction of PDT resistance. Disadvantages include the cessation of the antimicrobial effect when the light is turned off, and less than perfect selectivity for microbial cells over host tissue. This review will cover the use of PDT to kill or inactivate pathogens in ex vivo tissues and in biological materials such as blood. PDT has been successfully used to kill pathogens and even to save life in several animal models of localized infections such as surface wounds, burns, oral sites, abscesses and the middle ear. A large number of clinical studies of PDT for viral papillomatosis lesions and for acne refer to its antimicrobial effect, but it is unclear how important this microbial killing is to the overall therapeutic outcome. PDT for periodontitis is a rapidly growing clinical application and other dental applications are under investigation. PDT is being clinically studied for other dermatological infections such as leishmaniasis and mycobacteria. Antimicrobial PDT will become more important in the future as antibiotic resistance is only expected to continue to increase.

Application of a flexible CO2 laser fiber for neurosurgery: laser-tissue interactions

Object

The CO2 laser has an excellent profile for use in neurosurgery. Its high absorption in water results in low thermal spread, sparing adjacent tissue. Use of this laser has been limited to line-of-sight applications because no solid fiber optic cables could transmit its wavelength. Flexible photonic bandgap fiber technology enables delivery of CO2 laser energy through a flexible fiber easily manipulated in a handheld device. The authors examined and compared the first use of this CO2 laser fiber to conventional methods for incising neural tissue.

Methods

Carbon dioxide laser energy was delivered in pulsed or continuous wave settings for different power settings, exposure times, and distances to cortical tissue of 6 anesthetized swine. Effects of CO2 energy on the tissue were compared with bipolar cautery using a standard pial incision technique, and with scalpel incisions without cautery. Tissue was processed for histological analysis (using H & E, silver staining, and glial fibrillary acidic protein immunohistochemistry) and scanning electron microscopy, and lesion measurements were made.

Results

Light microscopy and scanning electron microscopy revealed laser incisions of consistent shape, with central craters surrounded by limited zones of desiccated and edematous tissue. Increased laser power resulted in deeper but not significantly wider incisions. Bipolar cautery lesions showed desiccated and edematous zones but did not incise the pia, and width increased more than depth with higher power. Incisions made without using cautery produced hemorrhage but minimal adjacent tissue damage.

Conclusions

The photonic bandgap fiber CO2 laser produced reliable cortical incisions, adjustable over a range of settings, with minimal adjacent thermal tissue damage. Ease of application under the microscope suggests this laser system has reached true practicality for neurosurgery.

In vivo comparison of simple and double-fractionated low-level laser irradiation schemes on the healing of rat skin lesions

OBJECTIVE

To compare the efficacy of a simple irradiation scheme with that of a double-fractionated irradiation scheme on the healing of rat skin lesions using in vivo monitoring of tissue diffuse reflectance.

BACKGROUND DATA

Low-level laser therapy (LLLT) is used in medicine for treating a wide range of pathological conditions. The practical benefits of laser treatment of acute and chronic conditions were obtained, using a single session of irradiation per day.

MATERIALS AND METHODS

Thirty Wistar rats were divided into three experimental groups (controls, simple laser irradiation scheme, and double-fractionated laser irradiation scheme). A skin lesion was created on the calf of the right hind leg of all rats. The laser irradiation parameters were lambda = 635 nm and power = 15 mW. The exposure time was 600 s for the simple laser irradiation scheme and 300 s x 2 for the double-fractionated laser irradiation scheme on 3 consecutive days. The optical properties of tissue were studied by processing and analyzing the diffuse reflectance spectra of injured skin, acquired before and after each laser irradiation.

RESULTS

The results demonstrate that, using a simple laser irradiation scheme (single daily irradiation session: t exp 1 =600 s, power = 15 mW, lambda = 635 nm), healing of the skin lesion began after 3 consecutive treatment days. The application of the double-fractionated laser irradiation scheme (2 daily irradiation sessions: t exp 2 = t exp 1/2 = 300 s, power = 15 mW and lambda = 635 nm) led to a reduction in treatment time to 2 days.

CONCLUSION

In conclusion, a double-fractionated irradiation scheme is more efficient than simple irradiation scheme for LLLT in rat skin lesions.