Treating onychomycosis with the short-pulsed 1064-nm-Nd:YAG laser: results of a prospective randomized controlled trial

Heterogeneous integration of an on-chip Nd:YAG whispering gallery mode laser with a lithium-niobate-on-insulator platform

The integration of heterogeneous optical components onto an optical platform is crucial for the advancement of photonic chips. To achieve this, efficient coupling of optical signals between components and the platform is essential. Here, we have successfully integrated a Nd:YAG microdisk laser with a lithium-niobate-on-insulator (LNOI) photonic platform by modulating the propagation modes of LNOI. Ridge waveguides are fabricated on the LNOI by carefully adjusting the cross-sectional dimensions to enable the propagation of higher-order propagation modes. This ridge waveguide ensures that the effective refractive index of the higher-order mode closely matches that of the fundamental mode of the Nd:YAG microdisk, ensuring efficient waveguide-microdisk coupling. This on-chip laser, consisting of an Nd:YAG microdisk and LNOI integration, achieves a maximum output power of 23 µW, and a mode suppression ratio of 53.6 dB. This research presents an efficient approach for constructing highly functional heterogeneous integrated optical chips.

Utility of devices for onychomycosis: a review

Onychomycosis is difficult to treat due to long treatment durations, poor efficacy rates of treatments, high relapse rates, and safety issues when using systemic antifungal agents. Device-based treatments are targeted to specific regions of the nail, have favorable safely profiles, and do not interfere with systemic agents. They may be an effective alternative therapy for onychomycosis especially with increasing reports of squalene epoxidase gene mutations and potential resistance to terbinafine therapy. In this review, we discuss four devices used as antifungal treatments and three devices used as penetration enhancers for topical agents. Lasers, photodynamic therapy, microwaves, and non-thermal plasma have the capacity to inactivate fungal pathogens demonstrated through in vivo studies. Efficacy rates for these devices, however, remain relatively low pointing toward the need to further optimize device or usage parameters. Ultrasound, nail drilling, and iontophoresis aid in improving the permeability of topical agents through the nail and have been investigated as adjunctive therapies. Due to the paucity in clinical data, their efficacy in treating onychomycosis has not yet been established. While the results of clinical studies point toward the potential utility of devices for onychomycosis, further large-scale randomized clinical trials following regulatory guidelines are required to confirm current results.

Onychomycosis: Old and New

Onychomycosis is a common chronic fungal infection of the nail that causes discoloration and/or thickening of the nail plate. Oral agents are generally preferred, except in the case of mild toenail infection limited to the distal nail plate. Terbinafine and itraconazole are the only approved oral therapies, and fluconazole is commonly utilized off-label. Cure rates with these therapies are limited, and resistance to terbinafine is starting to develop worldwide. In this review, we aim to review current oral treatment options for onychomycosis, as well as novel oral drugs that may have promising results in the treatment of onychomycosis.

Efficacy of Lasers for the Management of Dermatophyte Toenail Onychomycosis

BACKGROUND

Onychomycosis is a chronic fungal nail infection caused predominantly by dermatophytes, and less commonly by nondermatophyte molds and Candida species. Onychomycosis treatment includes oral and topical antifungals, the efficacy of which is evaluated through randomized, double-blind, controlled trials for US Food and Drug Administration approval. The primary efficacy measure is complete cure (complete mycologic and clinical cure). The secondary measures are clinical cure (usually ≤10% involvement of target nail) and mycologic cure (negative microscopy and culture). Some lasers are US Food and Drug Administration approved for the mild temporary increase in clear nail; however, some practitioners attempt to use lasers to treat and cure onychomycosis.

METHODS

A systematic review of the literature was performed in July of 2020 to evaluate the efficacy rates demonstrated by randomized controlled trials of laser monotherapy for dermatophyte onychomycosis of the great toenail.

RESULTS

Randomized controlled trials assessing the efficacy of laser monotherapy for dermatophyte toenail onychomycosis are limited. Many studies measured cure rates by means of nails instead of patients, and performed only microscopy or culture, not both. Only one included study reported mycologic cure rate in patients as negative light microscopy and culture (0%). The combined clinical cure rates in short- and long-pulsed laser studies were 13.0%-16.7% and 25.9%, respectively. There was no study that reported the complete cure rate; however, one did report treatment success (mycologic cure [negative microscopy and culture] and ≤10% clinical involvement) in nails as 16.7%.

CONCLUSIONS

The effectiveness of lasers as a therapeutic intervention for dermatophyte toenail onychomycosis is limited based on complete, mycologic, and clinical cure rates. However, it may be possible to use different treatment parameters or lasers with a different wavelength to increase the efficacy. Lasers could be a potential management option for older patients and onychomycosis patients with coexisting conditions such as diabetes, liver, and/or kidney diseases for whom systemic antifungal agents are contraindicated or have failed.

Big toenail onychomycosis features associated with response to 1064 nm Nd: YAG laser treatment

BACKGROUND

A few studies discussed the factors correlated to response in laser treatment of onychomycosis.

OBJECTIVE

This study aimed to seek big toenail onychomycosis features that correlate with response to 1064 nm Nd: YAG laser treatment.

METHODS

This single-center, retrospective study included patients who had only one big toenail onychomycosis, with a confirmed mycological diagnosis and/or a high clinical suspicion. Patients had three sessions 1 month apart. The following characteristics were collected from the patients' files: age, sex, smoking and arterial hypertension statuses, results of baseline mycological culture, Onychomycosis Severity Index (OSI) score at baseline and at the end of the 6-month follow-up, as well as the reported side effects.

RESULTS

We included 105 patients, 86 women and 19 men, with a mean age of 43 years. Demographics have shown that 73.6% of patients were smokers, 17.9% had arterial hypertension, 61.9% had a culture positive for Trichophyton species, and 9.4% had a culture positive for Candida species. According to the OSI score, onychomycosis was mild in 18.9%, moderate in 39.6%, and severe in 41.5% of patients. At 6 months, clinical cure was achieved in 57.1% of patients.

CONCLUSION

The OSI decrease after 3 sessions of Nd: YAG laser was significantly more important in women and in patients with positive mycology culture, smaller affected area of the nail, no subungual hyperkeratosis, and no nail matrix involvement. Age, smoking, hypertension, and side effects were not shown to significantly correlate with the decrease of the OSI score.

Topical and device-based treatments for fungal infections of the toenails

BACKGROUND

Onychomycosis refers to fungal infections of the nail apparatus that may cause pain, discomfort, and disfigurement. This is an update of a Cochrane Review published in 2007; a substantial amount of new research warrants a review exclusively on toenails.

OBJECTIVES

To assess the clinical and mycological effects of topical drugs and device-based therapies for toenail onychomycosis.

SEARCH METHODS

We searched the following databases up to May 2019: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase and LILACS. We also searched five trials registers, and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials.

SELECTION CRITERIA

Randomised controlled trials of topical and device-based therapies for onychomycosis in participants with toenail onychomycosis, confirmed by positive cultures, direct microscopy, or histological nail examination. Eligible comparators were placebo, vehicle, no treatment, or an active topical or device-based treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Primary outcomes were complete cure rate (normal-looking nail plus fungus elimination, determined with laboratory methods) and number of participants reporting treatment-related adverse events.

MAIN RESULTS

We included 56 studies (12,501 participants, average age: 27 to 68 years), with mainly mild-to-moderate onychomycosis without matrix involvement (where reported). Participants had more than one toenail affected. Most studies lasted 48 to 52 weeks; 23% reported disease duration (variable). Thirty-five studies specifically examined dermatophyte-caused onychomycosis. Forty-three studies were carried out in outpatient settings. Most studies assessed topical treatments, 9% devices, and 11% both. We rated three studies at low risk of bias across all domains. The most common high-risk domain was performance bias. We present results for key comparisons, where treatment duration was 36 or 48 weeks, and clinical outcomes were measured at 40 to 52 weeks. Based on two studies (460 participants), compared with vehicle, ciclopirox 8% lacquer may be more effective in achieving complete cure (risk ratio (RR) 9.29, 95% confidence interval (CI) 1.72 to 50.14; low-quality evidence) and is probably more effective in achieving mycological cure (RR 3.15, 95% CI 1.93 to 5.12; moderate-quality evidence). Ciclopirox lacquer may lead to increased adverse events, commonly application reactions, rashes, and nail alteration (e.g. colour, shape). However, the 95% CI indicates that ciclopirox lacquer may actually make little or no difference (RR 1.61, 95% CI 0.89 to 2.92; low-quality evidence). Efinaconazole 10% solution is more effective than vehicle in achieving complete cure (RR 3.54, 95% CI 2.24 to 5.60; 3 studies, 1716 participants) and clinical cure (RR 3.07, 95% CI 2.08 to 4.53; 2 studies, 1655 participants) (both high-quality evidence) and is probably more effective in achieving mycological cure (RR 2.31, 95% CI 1.08 to 4.94; 3 studies, 1716 participants; moderate-quality evidence). Risk of adverse events (such as dermatitis and vesicles) was slightly higher with efinaconazole (RR 1.10, 95% CI 1.01 to 1.20; 3 studies, 1701 participants; high-quality evidence). No other key comparison measured clinical cure. Based on two studies, compared with vehicle, tavaborole 5% solution is probably more effective in achieving complete cure (RR 7.40, 95% CI 2.71 to 20.24; 1198 participants), but probably has a higher risk of adverse events (application site reactions were most commonly reported) (RR 3.82, 95% CI 1.65 to 8.85; 1186 participants (both moderate-quality evidence)). Tavaborole improves mycological cure (RR 3.40, 95% CI 2.34 to 4.93; 1198 participants; high-quality evidence). Moderate-quality evidence from two studies (490 participants) indicates that P-3051 (ciclopirox 8% hydrolacquer) is probably more effective than the comparators ciclopirox 8% lacquer or amorolfine 5% in achieving complete cure (RR 2.43, 95% CI 1.32 to 4.48), but there is probably little or no difference between the treatments in achieving mycological cure (RR 1.08, 95% CI 0.85 to 1.37). We found no difference in the risk of adverse events (RR 0.60, 95% CI 0.19 to 1.92; 2 studies, 487 participants; low-quality evidence). The most common events were erythema, rash, and burning. Three studies (112 participants) compared 1064-nm Nd:YAG laser to no treatment or sham treatment. We are uncertain if there is a difference in adverse events (very low-quality evidence) (two studies; 85 participants). There may be little or no difference in mycological cure at 52 weeks (RR 1.04, 95% CI 0.59 to 1.85; 2 studies, 85 participants; low-quality evidence). Complete cure was not measured. One study (293 participants) compared luliconazole 5% solution to vehicle. We are uncertain whether luliconazole leads to higher rates of complete cure (very low-quality evidence). Low-quality evidence indicates there may be little or no difference in adverse events (RR 1.02, 95% CI 0.90 to 1.16) and there may be increased mycological cure with luliconazole; however, the 95% CI indicates that luliconazole may make little or no difference to mycological cure (RR 1.39, 95% CI 0.98 to 1.97). Commonly-reported adverse events were dry skin, paronychia, eczema, and hyperkeratosis, which improved or resolved post-treatment.

AUTHORS' CONCLUSIONS

Assessing complete cure, high-quality evidence supports the effectiveness of efinaconazole, moderate-quality evidence supports P-3051 (ciclopirox 8% hydrolacquer) and tavaborole, and low-quality evidence supports ciclopirox 8% lacquer. We are uncertain whether luliconazole 5% solution leads to complete cure (very low-quality evidence); this outcome was not measured by the 1064-nm Nd:YAG laser comparison. Although evidence supports topical treatments, complete cure rates with topical treatments are relatively low. We are uncertain if 1064-nm Nd:YAG laser increases adverse events compared with no treatment or sham treatment (very low-quality evidence). Low-quality evidence indicates that there is no difference in adverse events between P-3051 (ciclopirox hydrolacquer), luliconazole 5% solution, and their comparators. Ciclopirox 8% lacquer may increase adverse events (low-quality evidence). High- to moderate-quality evidence suggests increased adverse events with efinaconazole 10% solution or tavaborole 5% solution. We downgraded evidence for heterogeneity, lack of blinding, and small sample sizes. There is uncertainty about the effectiveness of device-based treatments, which were under-represented; 80% of studies assessed topical treatments, but we were unable to evaluate all of the currently relevant topical treatments. Future studies of topical and device-based therapies should be blinded, with patient-centred outcomes and an adequate sample size. They should specify the causative organism and directly compare treatments.

Laser treatment for onychomycosis: A systematic review and meta-analysis

BACKGROUND

Laser systems are a common treatment choice for onychomycosis. They exert their effects on inhibiting the growth of the fungus by selective photothermolysis but efficacy is dependent on the specific type of apparatus used. To systematically review the available published literature on the curative effects and safety of laser treatment for onychomycosis.

METHODS

Databases including PubMed, web of science, China National Knowledge Internet (CNKI), WanFang Database and VIP were searched systematically to identify relevant articles published up to July 2018. Potentially relevant articles were sourced, assessed against eligibility criteria by 2 researchers independently and data were extracted from included studies. A meta-analysis was performed using R software.

RESULTS

Thirty-five articles involving 1723 patients and 4278 infected nails were included. Meta-analysis of data extracted from these studies revealed that: the overall mycological cure rate was 63.0% (95%CI 0.53-0.73); the mycological cure rate associated with the 1064-nm Nd: YAG laser was 63.0% (95%CI 0.51-0.74); and that of CO2 lasers was 74.0% (95%CI 0.37-0.98). The published data indicate that laser treatment is relatively safe, but can cause tolerable pain and occasionally lead to bleeding after treatment.

CONCLUSION

Laser treatment of onychomycosis is effective and safe. The cumulative cure rate of laser treatment was significantly higher for CO2 lasers than other types of laser. Laser practitioners should be made aware of potential adverse effects such as pain and bleeding.

[Onychomycosis: Practical treatment strategies]

BACKGROUND

Onychomycosis is one of the most common nail diseases with an increasing number of cases. There is always a need for therapy because fungal nail infection never shows a tendency to spontaneous self-healing. Thus, the disease belongs to core competency of dermatologists.

CONCLUSION

Successful treatment requires a correct diagnosis based on meticulous anamnesis, the clinical findings as well as the identification of the pathogen fungus. Dermatoscopy and histological examination play an important role in this context. The algorithm as presented gives a concise overview of treatment.

A Randomized, Double-Blind, Controlled Trial Evaluating the Efficacy of Nd:YAG 1064 nm Short-Pulse Laser Compared With Placebo in the Treatment of Toenail Onychomycosis

Introduction:

Laser and light-based therapies have emerged as interesting treatment options with minimal side effects or contraindications to treat onychomycosis. Although increasing reports of successful treatment exist, few randomized, controlled, prospective studies have evaluated their true efficacy. We conducted a prospective, randomized, double-blind, controlled trial to evaluate the cure rate of onychomycosis treated by laser.

Methods:

Fifty-one patients were randomized to receive 3 treatments (0, 12, 24 weeks) of 1064 Nd:YAG short-pulse (Cutera GenesisPlus) laser or placebo sham laser. The primary efficacy end point is the proportion of patients with a complete cure rate of the target great toenail at week 52. The secondary efficacy end points, at week 52, were treatment success defined as almost clear nail (≤ 10%) and negative mycology, completely or almost clear nail of the great toenail, negative mycology, improvement from one OSI severity class to another of the target toenail, and the difference in proximal nail plate clearance between baseline and week 52.

Results:

No patient (0%) in the laser group and 2 patients (7.7%) in the placebo group reached the primary outcome. One patient (4.8%) in the laser group reached treatment success vs 2 (7.7%) in the placebo group. Only 6 patients (33%) had negative cultures in the laser group vs 11 (50%) in the placebo group. None of the secondary end points were met.

Conclusions:

This study demonstrated that 3 treatments of Nd:YAG 1064 nm laser at 3-month intervals were not effective to treat onychomycosis.

Laser therapy for onychomycosis in patients with diabetes at risk for foot ulcers: a randomized, quadruple-blind, sham-controlled trial (LASER-1)

BACKGROUND

Patients with diabetes mellitus are at high risk for onychomycosis, which is related to the development of foot ulcers.

OBJECTIVE

The aim of this study was to evaluate the safety and efficacy of the treatment of onychomycosis with local laser therapy.

METHODS

In a single-centre, randomized (1:1), quadruple-blind, sham-controlled trial, patients and microbiological confirmation with diabetes mellitus, at risk for developing diabetic foot ulcers (Sims classification score 1, 2) and a clinical suspicion on onychomycosis, were randomized to either four sessions neodymium-doped yttrium aluminium garnet (Nd-YAG) 1064 nm laser or sham treatment. The primary outcome was clinical and microbiological cure of onychomycosis after 1-year follow-up.

RESULTS

From March 2015 to July 2016, 64 patients were randomized; 63 could be analysed. Trichophyton rubrum was the most detected pathogen. There was no difference in the primary outcome between laser and sham treatment. With the exception of a subungual haematoma in the fifth toenail occurring 2 weeks after laser treatment, the results suggested that treatment with Nd-YAG 1064 nm laser is safe.

CONCLUSION

At this moment, there is no evidence of any effect of laser treatment for onychomycosis in patients with diabetes at increased risk for foot ulcers, at least not within 1 year after treatment.

Treatment of onychomycosis using a 1064-nm diode laser with or without topical antifungal therapy: a single-center, retrospective analysis in 56 patients

Background

Currently available treatment options for onychomycosis such as topical and systemic antifungals are often of limited efficacy, difficult to administer or associated with relevant side effects. Non-ablative laser therapy is proposed to represent a safe alternative without the disadvantages of drugs. Yet, to date, the efficacy of laser therapy for onychomycosis is discussed controversially. Against this background, we performed a systematic retrospective analysis of our clinical experience of 4 years of onychomycosis treatment applying a long-pulsed 1.064-nm diode laser.

Methods

We retrospectively evaluated the records of 56 patients with microscopic and culturally proven onychomycosis affecting a toenail of the hallux and other toes, who had been treated with a long-pulsed 1.064-nm diode laser (FOX, A.C.R. Laser GmbH, Nuremberg) during the time period of July 2013–December 2016 with or without concomitant topical antifungals. Thereof, 27 patients received laser treatment and 29 patients received laser treatment in combination with local antifungals. We conducted a mean of 3.9 laser treatments at 2–6-week intervals. The primary endpoint of our analysis was clinical improvement; secondary endpoints were complete remission of fungal pathogens in fungal culture and in microscopy.

Results

Clinical improvement was achieved in 56% of patients treated with laser only after a mean of 4.5 treatments and in 69% of patients treated with laser in combination with topical antifungals after a mean of 3.6 treatments. Cultural healing was detected in 63% of patients treated with laser only after a mean of 5.4 treatments, vs. 86% of patients treated with laser and concomitant topical antifungals after a mean of 4.8 treatments. Microscopic healing (complete healing) with the absence of fungal pathogens was achieved in 11% of patients after a mean of 4.7 treatments with laser only, vs. 21% of patients treated with laser and concomitant topical antifungals after a mean of 4 treatments. No relevant adverse effects were observed.

Conclusions

The 1.064-nm diode laser is an effective and safe option for the treatment of onychomycosis. Of note, the combination with topical antifungals will increase overall treatment efficacy and reduce the time to healing. Particularly, patients with contraindications against systemic antifungals may benefit from this multimodal therapeutic approach. Our data, moreover, suggest that treatment efficacy is positively correlated with the total number of laser treatments.

A practical application of onychomycosis cure - combining patient, physician and regulatory body perspectives

Due to the high relapse rates and the rise of predisposing factors, the need for curing onychomycosis is paramount. To effectively address onychomycosis, the definition of cure used in a clinical setting should be agreed upon and applied homogeneously across therapies (e.g. oral, topical and laser treatments). In order to determine what is or what should be used to define cure in a clinical setting, a literature search was conducted to identify methods used to evaluate treatment success. The limitations, strengths, prevalence and utility of each outcome measure were investigated. Seven ways to measure treatment success were identified; mycological cure, patient/investigator assessments, complete cure, quality of life instruments, severity indexes, clinical cure and temporary clearance. Despite its shortcomings, mycological cure is the most objective and consistent outcome measure used across onychomycosis studies. It is suggested that diagnostic goals of onychomycosis should be used to define cure in a clinical setting. Modifications to outcome measures such as incorporating molecular-based techniques could be a future avenue to explore.

Therapy of Skin, Hair and Nail Fungal Infections

Treatment of superficial fungal infections has come a long way. This has, in part, been through the development and evaluation of new drugs. However, utilising new strategies, such as identifying variation between different species in responsiveness, e.g., in tinea capitis, as well as seeking better ways of ensuring adequate concentrations of drug in the skin or nail, and combining different treatment methods, have played equally important roles in ensuring steady improvements in the results of treatment. Yet there are still areas where we look for improvement, such as better remission and cure rates in fungal nail disease, and the development of effective community treatment programmes to address endemic scalp ringworm.

Onychomycosis: Treatment and prevention of recurrence

Onychomycosis is a fungal nail infection caused by dermatophytes, nondermatophytes, and yeast, and is the most common nail disorder seen in clinical practice. It is an important problem because it may cause local pain, paresthesias, difficulties performing activities of daily living, and impair social interactions. The epidemiology, risk factors, and clinical presentation and diagnosis of onychomycosis were discussed in the first article in this continuing medical education series. In this article, we review the prognosis and response to onychomycosis treatment, medications for onychomycosis that have been approved by the US Food and Drug Administration, and off-label therapies and devices. Methods to prevent onychomycosis recurrences and emerging therapies are also described.

Light treatments of nail fungal infections

Nail fungal infections are notoriously persistent and difficult to treat which can lead to severe health impacts, particularly in the immunocompromized. Current antifungal treatments, including systemic and topical drugs, are prolonged and do not effectively provide a complete cure. Severe side effects are also associated with systemic antifungals, such as hepatotoxicity. Light treatments of onychomycosis are an emerging therapy that has localized photodynamic, photothermal or photoablative action. These treatments have shown to be an effective alternative to traditional antifungal remedies with comparable or better cure rates achieved in shorter times and without systemic side effects. This report reviews significant clinical and experimental studies in the field, highlighting mechanisms of action and major effects related to light therapy; in particular, the impact of light on fungal genetics.

Onychomycosis in the 21st Century: An Update on Diagnosis, Epidemiology, and Treatment

Onychomycosis accounts for 50% of all nail disease cases and is commonly caused by dermatophytes. Diabetes, human immunodeficiency virus, immunosuppression, obesity, smoking, and advancing age are predisposing factors of this fungal infection. Potassium hydroxide and culture are considered the current standard for diagnosing onychomycosis, revealing both fungal viability and species identification. Other diagnostic tests currently available include periodic acid-Schiff staining, polymerase chain reaction techniques, and fluorescent staining. Across 6 recently published epidemiology studies, the global prevalence of onychomycosis was estimated to be 5.5%, falling within the range of previously reported estimates (2%-8%). Newly approved onychomycosis treatments include efinaconazole, tavaborole, and laser therapy with lasers only approved to temporarily increase the amount of clear nail. Additional onychomycosis treatments being investigated include iontophoresis and photodynamic therapy with small open-label studies reported thus far. Preventative strategies, to help decrease recurrence and reinfection rates, include sanitisation of footwear and prophylactic topical antifungal agents.