Long-Pulsed 1064-nm Nd:YAG Laser for the Treatment of Onychomycosis

Compact 200 W level linearly polarized microsecond-pulse Nd:YAG oscillator with nearly diffraction-limited beam quality

A compact 200 W level diode-side-pumped microsecond (µs) pulse linearly polarized rod Nd:YAG laser oscillator was demonstrated with nearly diffraction-limited beam quality. The oscillator was based on a thermally near-unstable cavity design with two concave lenses in the cavity to enlarge the volume of the fundamental mode, leading to improvement of the laser efficiency and beam quality. Consequently, a record-high average power of 222 W was obtained at a repetition rate of 400 Hz with a 180 µs pulse width, corresponding to an optical-to-optical (o-o) conversion efficiency of 37%. The average beam quality factor was measured to be M²=1.32, resulting in a brightness value as high as of 11.25GW/sr⋅cm². To the best of our knowledge, this represented the highest average power, the highest o-o efficiency, and the highest brightness for a µs pulse 1064 nm rod Nd:YAG laser oscillator.

Laser Therapy for the Treatment of Morphea: A Systematic Review of Literature

Morphea, also known as localized scleroderma (LoS), comprises a set of autoimmune sclerotic skin diseases. It is characterized by inflammation and limited thickening and induration of the skin; however, in some cases, deeper tissues might also be involved. Although morphea is not considered a life-threatening disease, the apparent cosmetic disfigurement, functional or psychosocial impairment affects multiple fields of patients’ quality of life. Therapy for LoS is often unsatisfactory with numerous treatments that have only limited effectiveness or considerable side effects. Due to the advances in the application of lasers and their possible beneficial effects, the aim of this study is to review the reported usage of laser in morphea. We present a systematic review of available literature, performed with MEDLINE, Cinahl, Central, Scopus, Web of Science, and Google Scholar databases. We identified a total of twenty relevant studies (MEDLINE n = 10, Cinahl n = 1, Central n = 0, Scopus n = 2, Web of Science n = 5, Google Scholar n = 2) using laser therapy for LoS. Eight studies were focused on the use of PDL, six on fractional lasers (CO₂ and Er:YAG), four on excimer, and two on either alexandrite or Nd:YAG.

Effect of high-power Nd:YAG laser on the growth of Staphylococcus aureus and Pseudomonas aeruginosa: an experimental study

[Purpose] The aim of this study was to evaluate the effect of high-power Nd:YAG laser on Staphylococcus aureus and Pseudomonas aeruginosa bacterial growth. [Materials and Methods] Seven samples of S. aureus and seven samples of P. aeruginosa were prepared in the microbiology lab, one used as a control sample and the remaining six samples used as experimental samples, which were irradiated by a high-power laser (LASERSIX ME, 15W) with a total dose of 500 and 700 J. The primary measure was the semi-qualitative assessment of turbidity and bacterial count; the turbidity was assessed 24 h after laser application. [Results] There was a significant decrease in turbidity in all experimental samples of S. aureus and P. aeruginosa after 24 h of high-power laser application for 500 and 700 J and a significant decrease in the colony-forming unit (CFU) value in both types, and there were no significant differences in turbidity and CFU when comparing 500 and 700 J. [Conclusion] A high power Nd:YAG laser was found to be an effective modality for inhibition of S. aureus and P. aeruginosa growth.

Onychomycosis: An Updated Review

Background: Onychomycosis is a common fungal infection of the nail.

Objective: The study aimed to provide an update on the evaluation, diagnosis, and treatment of onychomycosis.

Methods: A PubMed search was completed in Clinical Queries using the key term “onychomycosis”. The search was conducted in May 2019. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews published within the past 20 years. The search was restricted to English literature. Patents were searched using the key term “onychomycosis” in www.freepatentsonline.com.

Results: Onychomycosis is a fungal infection of the nail unit. Approximately 90% of toenail and 75% of fingernail onychomycosis are caused by dermatophytes, notably Trichophyton mentagrophytes and Trichophyton rubrum. Clinical manifestations include discoloration of the nail, subungual hyperkeratosis, onycholysis, and onychauxis. The diagnosis can be confirmed by direct microscopic examination with a potassium hydroxide wet-mount preparation, histopathologic examination of the trimmed affected nail plate with a periodic-acid-Schiff stain, fungal culture, or polymerase chain reaction assays. Laboratory confirmation of onychomycosis before beginning a treatment regimen should be considered. Currently, oral terbinafine is the treatment of choice, followed by oral itraconazole. In general, topical monotherapy can be considered for mild to moderate onychomycosis and is a therapeutic option when oral antifungal agents are contraindicated or cannot be tolerated. Recent patents related to the management of onychomycosis are also discussed.

Conclusion: Oral antifungal therapies are effective, but significant adverse effects limit their use.Although topical antifungal therapies have minimal adverse events, they are less effective than oral antifungal therapies, due to poor nail penetration. Therefore, there is a need for exploring more effective and/or alternative treatment modalities for the treatment of onychomycosis which are safer and more effective.

Long-Term Follow-Up for Q-Switched Nd:YAG Treatment of Nevus of Ota: Are High Number of Treatments Really Required? A Case Report

Objective: Q-switched laser is considered a gold standard treatment for Nevus of Ota (NO). We report how few laser sessions in long intervals of time may achieve satisfying outcomes reducing the rate of possible procedure-linked side effects such as burning, cornea injuries, or hyperpigmentation. Background: NO represents a congenital dermal melanocytosis in the trigeminal distribution majorly occurring in Asian individuals. Multiple reports have shown efficacy and safety of Q-switched laser for the treatment of this condition, but they were based on an empiric regimen, often leading to unnecessary overtreatments. At the best of our knowledge, no long-term follow-up observations of single laser sessions have been conducted to assess the proper intervals and number of treatments. Materials and methods: A 36-year-old Asian woman, Fitzpatrick skin type IV with clinical diagnosis of NO, was treated with 1064 nm 6 ns Q-switched laser one session per year for a total of two sessions. Clinical result was valued by two physicians independently using standardized and polarized light. No use of general anesthesia or sedation was needed in our experience. Corneal shields have been used. Results: After only two sessions of the Q-switched laser performed 1 year apart, the result was excellent with a 95% of clinical response. No side effect was observed. Conclusions: In our experience, Q-switched Nd:YAG laser is an effective treatment for NO with no necessity of high number of treatments. A larger population is needed to confirm this preliminary result.

[Long-pulsed 1064 nm Nd: YAG laser combined with terbinafine against chromoblastomycosis caused by Fonsecaea nubica and the effect of laser therapy in a Wistar rat model]

We report a case of chromoblastomycosis caused by Fonsecaea nubica, which was successfully treated by long-pulsed 1064 nm Nd: YAG laser combined with terbinafine. A 60-year-old man was admitted for the presence of a 30 mm×40 mm erythematous plaque on the dorsum of his right hand for about 10 months without any subjective symptoms. Both microscopic examination and tissue biopsy of the lesion showed characteristic sclerotic bodies of chromoblastomycosis. Lesion tissue culture on SDA at 26 ℃ for 2 weeks resulted in a black colony, and slide culture identified the isolate as Fonsecaea species. ITS sequence analysis of the isolate showed a 99% homology with F. nubica strain KX078407. The in vitro susceptibility of the isolate to 9 antifungal agents was determined using the microdilution method according to the guidelines of CLSI M38-A2 protocol, and terbinafine showed the lowest MIC (0.125 μg/ml). We subsequently established a Wistar rat model of chromoblastomycosis using the clinical isolate F. nubica and treated the rats with long-pulsed 1064 nm Nd: YAG laser (pulse width of 3.0 ms, fluence of 24 J/cm², spot size of 3 mm, frequency of 4 Hz, repeated 3 times at an interval of 30 s) twice a week for a total of 8 sessions. Although the laser treatment alone was not able to eliminate the fungi, histopathological examination showed the aggregation of numerous lymphocytes in the local affected tissue, indicating an immune response that consequently facilitate the regression of the lesion. The patient was successfully treated by long-pulsed 1064 nm Nd: YAG laser once a week combined with terbinafine (0.25 /bid) for 8 weeks, and follow-up for 20 months did not reveal any signs of recurrence.

Effects of Nd:YAG laser irradiation on the growth of Candida albicans and Streptococcus mutans: in vitro study

The purpose of this study was to evaluate the effects of Nd:YAG laser with flat-top handpiece on the in vitro growth of Candida albicans and Streptococcus mutans. The incidence of C. albicans (opportunistic commensal) and S. mutans (facultatively anaerobic) infections is increasing, despite available treatments. Cultures of Streptococcus mutans and Candida albicans were irradiated using Nd:YAG laser (LightWalker, Fotona) with flat-top handpiece (Genova, LightWalker, Fotona) at the following parameters: group G1: 0.25 W, 10 Hz, 15 s, 3 J and group G2: 1 W, 10 Hz, 60s, 59 J. The results were evaluated directly and 24 h after irradiation using a quantitative culture method (estimation of colony-forming units in 1 ml of suspension, cfu/ml), and microscopic analysis with Janus green stain and compared with control group in which laser was not applied. C. albicans was reduced by 20 up to 54% for G1, and for G2 by 10 up to 60% directly after the application. The cfu/ml values for S. mutans decreased by 13% (p = 0.1771) for G1 and 89% (p < 0.0001) for G2. In both test groups 24 h after the application, the number of colony-forming units decreased by 15–46% for G1 and by 15–64% for G2. The arrested cell division, increasing the surface area and increasing the number of metabolically inactive cells, were observed in morphometric analysis. Macroscopic and microscopic analyses revealed a reduction in cell number and a significant decrease of cell metabolism after laser application for both C. albicans and S. mutans.

[Effect of 0.9-ms 1064-nm Nd:YAG laser combined with itraconazole for treatment of toenail onychomycosis]

OBJECTIVE

To evaluate the efficacy and safety of 0.9-ms 1064-nm Nd:YAG laser alone or combined with itraconazole for treatment of toenail onychomycosis.

METHODS

A total of 37 patients with onychomycosis (178 toenails) were randomly assigned to groups A and B, and each group was further divided into different subgroups according to the Scoring Clinical Index of Onychomycosis (SCIO) and Onychomycosis Severity Index (OSI) scoring. All the patients were treated with 0.9-ms Nd:YAG laser once a week for 8 times. The patients in group A were treated with laser alone, and those in group B were treated with laser combined with itraconazole. The clinical effect, clinical scores, appearance of the toenails and adverse reactions in the two groups were analyzed, and the patients' satisfaction rate was also investigated.

RESULTS

At the 12th months of follow-up, the clinical response rate and mycological cure rate in group A were 31.33% and 30.00%, respectively, similar to the rates in group B (35.79% and 41.18%, respectively) (P>0.05). After the treatments, the SCIO and OSI scores showed no significant changes in group A (P>0.05) but both increased significantly in group B (P<0.05). The response rates did not differ significantly among the subgroups with SCIO<12 or with OSI<16 (P>0.05), but showed significant differences among the subgroups with SCIO≥12 or with OSI≥16 (P<0.05). Of the total of 178 toenails, 33.71%, 74.72% and 70.79% toenails showed improvements in terms of clear nail growth, shape and color, respectively. The overall patients' satisfaction rate was 62.16%, and no adverse reactions related with the therapy were recorded in these patients.

CONCLUSION

For treatment of toenail onychomycosis, 0.9-ms 1064-nm Nd:YAG laser can effectively improve the aesthetic appearance of the toenails, and a combined treatment with Nd:YAG laser and itraconazole can be better option in severe cases of onychomycosis.

Treatment of Dermatophytosis in Elderly, Children, and Pregnant Women

Dermatophytic infection of the skin and its appendages is a common occurrence. Though usually straightforward, treatment of dermatophytosis becomes notably challenging in certain population groups - pregnant women, children, and elderly. Treatment with topical azoles/allylamines alone is effective in limited cutaneous disease in all three groups. Terbinafine is the preferred oral agent in elderly population for treatment of extensive cutaneous disease and onychomycosis due to its lack of cardiac complications and lower propensity for drug interactions. If required, additional physical/mechanical modalities can be employed for symptomatic onychomycosis. Data for systemic therapy in children mainly pertains to the treatment of tinea capitis. At present, very little data exists regarding the safety of systemic antifungals in pregnancy and there is an effort to restrict treatment to topical therapies because of their negligible systemic absorption.