Alexandrite Laser Research Articles

Laser therapy and light sources for labial lentigines in patients with Peutz-Jeghers syndrome.

Labial lentigines associated with Peutz-Jeghers syndrome are challenging and represent a cosmetic problem. Laser and intense-pulsed light sources (IPLS) can be used to treat these macules. However, there are few guidelines regarding the different types of protocols found in the literature. Thus, the purpose of this study was to review the pertinent literature on lasers and IPLS as therapy for labial lentigines in patients with Peutz-Jeghers syndrome. A detailed literature search was conducted in seven databases (Cochrane Library, Embase, Lilacs, PubMed, SciELO, Scopus and Web of Science) to November 2020. Data were extracted and analyzed from selected studies including study design, sample size, participants' skin color, age, and gender, parameters of the laser or IPLS used, interval and total sessions of laser application, results obtained, follow-up time and side effects. Thirteen out of 124 published studies met our eligibility criteria, covering 81 patients. Ten types of lasers and IPLS were used, and most of the sample (n=57) was treated with Q-switch Alexandrite Laser (QSAL). The total number of sessions ranged from 1 to 12 and the interval between sessions ranged from 2 to 16 weeks. All studies have shown satisfactory results, with no further complications. The follow-up ranged from 2 to 97 months. Laser therapy and IPLS are effective in the treatment of lentigines associated with PJS. Although QSAL was used in 70.3% of the sample, different types of lasers showed comparable satisfactory results.

Successful Treatment of Recalcitrant Plantar Warts Using Combined Long-pulsed Nd:YAG and Alexandrite Lasers

Successful Treatment of Recalcitrant Plantar Warts Using Combined Long-pulsed Nd:YAG and Alexandrite Lasers

High repetition rate diode-pumped self-pulsed few-cycle alexandrite laser

We reported a high repetition rate diode-pumped alexandrite femtosecond laser using a simple linear cavity. Laser emission spectrum was as broad as ∼20 nm by inserting a 0.5-mm-thick quartz birefringent plate as a spectral modulation component. Pulse duration as short as few-cycle 36 fs with the repetition rates of 2.48 GHz was measured at pump power of 17 W. To the best of our knowledge, this is the shortest pulse duration achieved in the alexandrite lasers.

Depilatory laser miniaturizes hair by inducing bystander dermal papilla cell necrosis through thermal diffusion.

Depilatory laser targeting melanin has been widely applied for the treatment of hypertrichosis. Both selective photothermolysis and thermal diffusion have been proposed for its effect, but the exact mechanism of permanent hair reduction remains unclear. In this study, we explore the role of thermal diffusion in depilatory laser-induced permanent hair loss and determine whether nonpigmented cells are injured by thermal diffusion. C57BL/6 mice in anagen and telogen were treated with alexandrite laser (wavelength 755 nm, pulse duration 3 milliseconds, fluence 12 J/cm2 , spot size 12 mm), respectively. Histological analysis, terminal deoxynucleotidyl transferase dUTP nick-end labelingassay, and transmission electron microscopic imaging were employed to evaluate the injury to hair follicle (HF)cells. The proliferation status of HF cells was examined by 5-bromo-2'-deoxyuridinepulse labeling. The number of HF stem cells was quantified by fluorescence-activated cell sorting. The size of the regenerated hair was determined by measuring its length and width. We found that irradiating C57BL/6 mice in anagen with alexandrite laser led to hair miniaturization in the next anagen. In addition to thermal disruption of melanin-containing cells in the precortex region, we also detected necrosis of the adjacent nonpigmented dermal papilla cells due to thermal diffusion. Dermal papilla cells decreased by 24% after laser injury, while the number of bulge stem cells remained unchanged. When the laser was delivered to telogen HFs where no melanin was present adjacent to the dermal papilla, thermal necrosis and cell reduction were not detected in the dermal papilla and no hair miniaturization was observed. Our results suggest that depilatory laser miniaturizes hair by inducing thermal necrosis of dermal papilla cells due to secondary thermal diffusion from melanin-containing precortex cells in the anagen hair bulbs.

Multipass low fluence, high-frequency 755-nm alexandrite laser versus high fluence, low-frequency 1064-nm long-pulsed Nd: YAG laser in axillary hair reduction of dark skin phototypes: an intra-individual randomized comparative study

Background Laser hair removal has become popular means of achieving hair reduction with improved quality of life. Objective This study aimed to assess the safety and efficacy of Multipass low fluence, high-frequency 755-nm Alexandrite laser versus the high fluence, low-frequency 1064-nm long-pulsed Nd: YAG laser on axillary hair reduction in women with dark skin phototypes. Patients and methods This study was carried out on 30 adult women [skin type, IV-VI)] who seek axillary hair reduction. These subjects were adjusted to receive 5 laser sessions with a 1-month interval. One side received high fluence, low-frequency 1064-nm laser where the other side received multipass low fluence, high-frequency 755 nm laser. The follow-up was done using photographs, folliscope, patients’ visual analog pain scale. Results The mean percentage of hair density reduction showed significant improvement in both treated sides being higher in the Alex treated side with corresponding significant decreases in the mean hair thickness. Conclusion Multipass low fluence, high-frequency 755-nm Alex laser practice was verified to be safe and effective for hair removal in dark skin phototypes compared to the high fluence, low frequency 1064-nm long-pulsed Nd:YAG laser.

Randomized, evaluator-blinded comparative study of a potassium titanyl phosphate (KTP) 532-nm picosecond laser and an alexandrite 755-nm picosecond laser for the treatment of solar lentigines in Asians.

Various pigment-specific lasers can be used to treat solar lentigines. However, the most effective treatment options remain to be explored to reduce complications, such as postinflammatory hyperpigmentation, especially in dark-skinned patients. This study aims to compare the efficacy and safety between the KTP 532-nm picosecond laser and the alexandrite 755-nm picosecond laser for the treatment of solar lentigines in Asians. Thirty patients who had at least two solar lentigines on their arms were enrolled. A total of 30 paired lentiginous lesions were randomly selected for a single treatment with either a KTP 532-nm picosecond laser or an alexandrite 755-nm picosecond laser. Mean luminance score (L*) was evaluated at baseline and at 6 and 12weeks to determine treatment efficacy. Improvement was assessed by a blinded physician using a 5-point score. Satisfaction was rated by patients using a visual analog scale. All adverse events were documented. All 30 patients completed the study. Both lasers showed significant improvement in mean L* from baseline (p<0.001). With the parameter settings employed, lesions treated with the alexandrite 755-nm picosecond laser showed greater improvement in mean L* when compared with treatment with the KTP 532-nm picosecond laser at 12weeks follow-up (p=0.002). According to physician scoring, more than 50% improvement was observed in 25 and 19 lesions of the alexandrite 755-nm picosecond laser group and the KTP 532-nm picosecond laser group, respectively. Adverse events did not differ between groups. A significantly higher satisfaction score was observed with the alexandrite 755-nm picosecond laser at the last visit (p=0.038). Both types of picosecond laser may be used to treat solar lentigines. Proper treatment settings and endpoint observation are the most important factor to achieve a successful outcome.

Volume Bragg Grating Locked Alexandrite Laser

We report the first ever demonstration of a wavelength-locked Alexandrite laser using a volume Bragg grating (VBG) as a wavelength-selective mirror. Output power of 3.3 W with a diffraction limited beam quality of M2=1.1 was obtained at a lasing wavelength of 762.2 nm and a linewidth (FWHM) of 2.5 GHz.

Cavity-dumped mode-locked Alexandrite laser oscillator with 100 mJ pulses stabilized by using a double trigger system.

We report a mode-locked Alexandrite single pulse laser with cavity dumping. Mode locking was achieved by using an AOM and an EOM was used for Q-switching and cavity dumping. The instability of the single pulse laser energy output was reduced down to a tenth of that of the conventional single trigger system by introducing a novel double trigger system. The single pulse laser energy and pulse width were 100 mJ and 475 ps in multiple mode and 12.5 mJ and 275 ps in single mode, obtained without a laser amplifier.

Treatment protocols and efficacy of light and laser treatments in post-acne erythema.

Post-acne erythema is described as erythema due to release of inflammatory cytokines, dilatation of microcapillaries within papillary dermis and thinning of epidermis. The erythema usually fades; however, it can persist for months. In this review, we decided to evaluate efficacy of light and laser treatments in acne-induced erythema. We searched PUBMED, Embase, Cochrane, and Google Scholar for relevant key words. Inclusion criteria were randomized clinical trials (RCTs) that evaluated efficacy of laser or light in PAE until September 2021. Twelve RCTs were selected for the final assessment. Light and laser treatments included pulsed dye laser (PDL), intense pulsed light (IPL), Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG), fractional photothermolysis, alexandrite, solid-slate 589-1319nm, and pro-yellow laser. Light and laser treatments are effective treatment modalities in reduction of acne-induced erythema along with active acne lesions and atrophic acne scars.

LD Pumped Watt-Level Actively Q-switched Alexandrite Laser

LD Pumped Watt-Level Actively Q-switched Alexandrite Laser

Alexandrite laser as an adjuvant therapy in the management of mild to moderate hidradenitis suppurativa: A controlled prospective clinical study

Alexandrite laser as an adjuvant therapy in the management of mild to moderate hidradenitis suppurativa: A controlled prospective clinical study

Evaluation of Picosecond 755-nm Alexandrite Laser With a Diffractive Lens Array on Pore Size Reduction.

Medications, lasers and light therapy have all been shown to transiently minimize pore size. Current research of the 755-nm Alexandrite picosecond laser (Cynosure, MA) on pore size shows differing results regarding the efficacy, with one study of Asian volunteers (Fitzpatrick skin type IV) reporting &ldquo;marked&rdquo; improvement of pores, yet another study reporting no significant improvement in pore size in Chinese patients (Fitzpatrick skin type III&ndash;IV), causing some contention. This study aims to rectify the discordant results through the examination of the 755-nm Alexandrite picosecond laser on pore size reduction in a sample consisting of Fitzpatrick skin type I&ndash;III. Patients who received 755-nm Alexandrite picosecond laser treatment for photorejuvenation, (6 mm lens array) with a fluence of 0.71 J/cm2 of the face or head, with at least two treatments over four-week intervals were included in the study. A precision subject imaging system (Canfield VISIA&reg; Complexion Analysis Generation 7, NJ) was used to assess three parameters of pore size (feature count, score, percentile rank) at each time period at right lateral, left lateral and frontal views. A Wilcoxin signed rank test was performed to compare differences between time periods and a mixed model ANOVA was utilized to account for patients who received less than three treatments. Significance level set to P=&lt;0.05. 32 participants met criteria and underwent at least two picosecond laser treatments for photorejuvenation. There was an overall reduction in pore count in approximately 57% of participant data points from times 1 to 2 and 50% reduction from times 2 to 3. There was a 100% pore count reduction observed from baseline compared with the follow-up visit four weeks after the third treatment, at time 4. Further, there was a significant improvement of pores demonstrated by score from times 1 to 3 (Z= -2.197, P=0.028) as well as percentile rank between times 1 and 2 (Z= -2.070, P=0.038) and times 1 and 3 (Z= -2.201, P=0.028). Future studies should investigate the longterm effect of 755-nm Alexandrite picosecond laser on pore size reduction as continued patient recruitment and data collection is necessary to effectively discern the 755-nm Alexandrite picosecond laser debate. Thus, prolonged follow up post treatment should be evaluated in order to determine if results are maintained. Nonetheless, the 755-nm Alexandrite picosecond laser shows promising results for the improvement of skin pores thus far. J Drugs Dermatol. 2021;20(12):1302-1306. doi:10.36849/JDD.6199.

Efficacy Evaluation of 755-nm Long-Pulse Alexandrite Laser Combined with 0.5% Timolol Maleate Eye Drops in the Treatment of Thicker Infantile Hemangioma.

PurposeAssessment of the clinical effectiveness and safety of 755-nm long-pulse alexandrite laser combined with 0.5% timolol maleate eye drops in treating thicker infantile hemangioma (IH).Materials and MethodsRetrospective analysis of IH treated with 755-nm long-pulse alexandrite laser and topical timolol in the Second Affiliated Hospital of Wenzhou Medical University from October 2019 to October 2020. Seventy-eight cases were included, with a five-week laser treatment interval. Treatment status was documented during the 35 weeks before each treatment, the effect was assessed at the visual analog scale (VAS), and side effects were recorded. During the 6-month follow-up period, the recurrence and residual skin lesions were monitored. The relationship between IH thickness, treatment duration and VAS was analyzed.ResultsAmong the 78 children with hemangioma, 4 children were treated with a combination of propranolol, fractional laser and cinnamyl alcohol injection due to poor curative effect. Finally, the lesions were effectively alleviated. At the 5th, 15th, 25th, and 35th weeks of treatment, the average VAS of 74 children were 3.56 ± 1.20, 4.61 ± 1.43, 5.63 ± 1.60, and 6.63 ± 1.72, respectively. We analyzed VAS in different thickness groups with Repeated Measures Analysis of Variance(RMANOVA). The results show that the VAS of the thickness 2–3 mm and 3–5mm groups were higher than the 5–7mm and 7–8mm groups (F group = 440.54, P <0.05, F time = 448.31, P <0.05). During the 6-month follow-up period, none of the 74 children relapsed and the residual skin lesions gradually vanished.ConclusionCombined treatment of IHs with a 755-nm long-pulse alexandrite laser and 0.5% timolol maleate eye drops which has apparent clinical efficacy and safety reduce residual skin lesions and decrease the IH recurrence rate.

755-nm Alexandrite Picosecond Laser with a Diffractive Lens Array or Zoom Handpiece for Post-Inflammatory Hyperpigmentation: Two Case Reports with a Three-Year Follow-Up.

ObjectivePost-inflammatory hyperpigmentation (PIH) is a reactive hypermelanosis of various skin types, which occurs as a sequela of cutaneous inflammation or injury. Despite generally a self-limited and temporary condition, PIH is still a frustrating problem that can have significant psychosocial effects on patients, especially those with darker skin types. Laser therapy is one of the effective treatments for PIH, and various wavelength lasers and light devices have been utilized in PIH therapy. Nonetheless, data on the long-term efficacy of the 755-nm alexandrite picosecond laser are limited.MethodsThis study analyzed two cases of PIH treated with a combination of a 755-nm alexandrite picosecond laser and a diffractive lens array or zoom handpiece. Efficacy of the treatment was determined by the images of skin lesions under a fixed light source before and after each treatment, which were independently reviewed by two plastic-surgery specialists blinded to the clinical data. Improvement was classified as complete (>75%), significant (50–75%), mild (25–50%), and inefficient (<25% or no obvious change). Skin imaging analysis was carried out using the VISIA system (Canfield, USA), and dermoscopy was performed at the same time.ResultsAfter two to three courses of treatment, all cases showed significant or complete improvement, and no recurrence was observed during the three years of follow-up.ConclusionA 755-nm alexandrite picosecond laser in combination with a diffractive lens array or zoom handpiece had significant and long-term efficacy for the treatment of PIH caused by trauma. However, attention should be paid to the problem of transient deepening of pigmentation during treatment.

The use of CO2 ablative fractional laser, non-ablative picosecond fractional lasers 1064 nm and 755 nm and needle mesotherapy in combined therapy to reduce stretch marks and skin laxity. A clinical case

Stretch marks are a common problem and a challenge for cosmetologists and aesthetic medicine doctors. Due to the complex etiopathogenesis and difficulties in their reduction, specialists use various therapeutic methods. In this study, the described case confirms the effectiveness of selected combined therapy in reducing stretch marks and skin laxity. Impressive surgical results were obtained with the implementation of combined therapy consisting of the use of non-ablative Nd:YAG fractional laser and alexandrite laser in picosecond technology, CO2 fractional ablative laser and needle mesotherapy treatments.

Vascular damage mechanism and parameter optimization under alexandrite laser irradiation: a theoretical study.

The 755-nm Alexandrite Laser has a good clinical effect in treating resistant port wine stain, without causing thermal damage of normal tissue and side effects such as purpura. However, little is known about the mechanism of vascular damage induced by 755-nm laser irradiation, which restricts the optimization of laser parameters. In this work, the thermal damage model and the pressure damage model were used to study the damage mechanism of 755-nm laser irradiation on vessels, and the incident energy density and pulse width required for vascular damage were determined according to the damage mode. Under the irradiation of 755-nm laser, the vascular injury pattern was the co-occurrence of vessel rupture and vessel constriction, and the energy density required for the treatment of vessels with a diameter of 200μm to reach the damage threshold was the lowest.

Utilization of Alexandrite Laser for Hair Removal in Pediatric Auricular Reconstruction.

Auricular reconstruction with autologous rib cartilage involves using a soft tissue envelope to cover the cartilage framework. In patients with a low hairline, hair-bearing skin may be incorporated on the reconstructed ear, creating a difficult and conspicuous aesthetic problem. A retrospective chart review was conducted to summarize and share the experience of using the Candela GentleMax Pro 755-nm alexandrite laser system (Candela Corp) in children following auricular reconstruction. Nine patients received laser hair removal via the alexandrite laser system with good results. The number of completed sessions ranged from 1 to 5. The procedures were completed without the need for premedication or procedural sedation. Laser hair removal with an alexandrite laser system was safe, fast, and effective. With multistage auricular reconstruction, it was feasible to incorporate laser hair removal between the stages.

Adverse reactions after laser, IPL and LED procedures

The fast-paced everyday life and the modern perception of beauty impose increasingly faster, effective and affordable methods for maintaining a good appearance. Laser systems providing great therapeutic possibilities meet the expectations and needs of doctors and patients. When used wisely and being familiar with their contraindications in details, side effects after laser therapy are relatively rare. However, some of them can be serious and significantly impair the quality of life. Although these methods are often called „laser procedures”, the devices used are not always real lasers - for example IPL, LED, Titan, infrared energy-based technologies and radio frequency procedures, such as Thermage. Among the widely used laser systems are Nd:YAG, Er:YAG, Alexandrite, CO2 and diode lasers. We distinguish mainly two types of systems used for cosmetic purposes: ablative and non-ablative. Each laser system has its own profile of complications specific to the treated skin lesion. Possible complications should be fully discussed with the patient as part of the informed consent procedure.

A case of Nevus of Ota treated with laser picosecond Alexandrite 755 nm: A case-report

Background: Nevus of Ota is a well-defined dermal melanocytosis characterized by bilateral multiple small, bluish-brown macules in the area innervated by the first and second branches of the trigeminal nerve. Currently, the therapeutic modalities for this condition are still limited and complete resolution is difficult to achieve.Case Description: A 23-year-old woman complained a brown spot on the right cheek since the patient was born. It looked like the skin but slightly darker than its surroundings. Four years ago the patient had received 6 sessions of QS: Nd-YAG laser therapy, but the spot is still clearly visible. Dermatological status of the orbital, infraorbital, zygomatic, and right buccal regions showed multiple hyperpigmented patches, gray-brown, well-defined, geographically in shape with size 0.2 x 0.3cm – 5 x 7cm. The lesion was unilateral and distributed within the innervation area of the second and third trigeminal nerve. Miravex® skin analysis showed that the average level of melanin was 0.464 with a melanin variation of 45%. Therefore, patient was diagnosed with Nevus of Ota. The proposed treatment was picosecond alexandrite 755nm laser, with a frequency of 2.5 Hz, pulse duration 550-750 ps, spot size 4 mm, and fluence 1.59 J/cm2. A marked improvement was observed after the treatment and after 21 days, a good grade of improvement was reported.Conclusion: Nevus of Ota can effectively treated with 755nm picosecond alexandrite laser therapy and results in a good grade of improvement.

COMPARATIVE ASSESSMENT OF TATTOO REMOVAL WITH SINGLE SESSION OF R20 TECHNIQUE AND CONVENTIONAL TECHNIQUE

Background: Most suitable devices for tattoo removal at present are Q-switched ruby, Nd:YAG and Alexandrite lasers. 1 These are the current gold standard for laser tattoo removal . But there are few limitations, such as long duration of treatment, large interval between sessions; side effects such as blistering, scarring and dyschromia. The current methods attempted to reduce the total number of sessions and total duration to achieve clearing of tattoos. R20 method of tattoo removal is based on principle of repeated exposure of laser light in a single session. Aim: 1) to compare lightning of tattoos with a single pass Q-switched laser treatment with 4 treatment passes separated by 20 minutes 2) To compare the Adverse effects between two methods Methods and Material: It included 50 patients and were divided in half and randomized. Half of them received single pass treatment with Q-switched Nd:YAG laser 1064 nm used at energy of 360 mJ. Other half received multipass treatment (each pass at 20 minutes interval with maximum of 4 pass). Tattoo lightening and adverse effects compared 1month later i.e. after single session. Results: 1 month later, treatment with the R20 method was much more effective than conventional single-pass laser treatment. With R20 method, 100% patients experienced immediate erythema and edema, 16% patient experienced blistering, crusting. No obvious Scarring/permanent pigmentary changes in any patient. &gt;75% fading experienced by 18 patients after single session, 50-75% fading in 4 patients, 40% experienced transient hypopigmentation. With single pass technique, all patients experienced &lt;50% fading. Conclusion: With R20 method the number of sessions required for tattoo removal is greatly reduced thus decreasing the number of visits. It is more effective but also safe in most of the patients. The disadvantages are one single session can take 3½ to 4 hours.