Abstract: LU Sheng, ZHANG Zhen, FEI Ye, CHEN Xiang-dong. Department of Dermatology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China Corresponding author: CHEN Xiang-dong, Email: xdchen@medmail.com.cn 【Abstract】 Objective To evaluate the efficacy and safety of long pulsed Nd:YAG laser in the treatment of onychomycosis. Methods Thirty-five patients with onychomycosis were treated by long pulsed Nd:YAG laser with a wavelength of 1064 nm, power of 30－40 J/cm2, pulse width of 35 milliseconds, diameter of light spot of 4 mm. One treatment session included 4 times of irradiation at an interval of 2 minutes. Patients were treated once a week for 4 weeks followed by once a month for 6 months. Clinical and mycological efficacy was evaluated 9 months after the beginning of treatment. Side effects were recorded and analyzed. Nails were divided into various groups according to causative fungal species, clinical phenotypes, and distribution of affected nails. Data were processed by using SPSS 17.0 software. Chi-square test was performed to compare the response and recurrence rate between these groups. Results A total of 79 nails were treated by long pulsed Nd:YAG laser in this study. At 9 months after the first treatment, clinical response was observed in 67.1% of these nails, mycological response in 73.4%, and recurrence in 19.0%. The Trichophyton rubrum group showed a better clinical （χ2 = 10.913, P < 0.05） and mycological response （χ2 = 13.532, P < 0.05）, but a lower recurrence/reinfection rate （χ2 = 10.980，P < 0.05） compared with the other-species group. No significant difference was observed between the Trichophyton rubrum group and Candida albicans group in the clinical and mycological response rate or recurrence/reinfection rate. The clinical response in the distal lateral subungual onychomycosis （DLSO） group was significantly poorer than that in the white superficial onychomycosis （WSO） group（χ2 = 11.935, P < 0.05）, but better than that in the proximal subungual onychomycosis （PSO）/total dystrophic onychomycosis （TDO） group（χ2 = 17.515, P < 0.05）. Increased clinical response rate was observed in the second－fifth finger nail group compared with the thumb nail/second－fifth toe nail group（χ2 = 13.437, P < 0.05）and hallux nail group （χ2 = 10.595, P < 0.05）, while no statistical difference was observed in clinical response rate between the hallux nail group and thumb nail/second－fifth toe nail group （χ2 = 3.030, P > 0.05）, or in mycological response rate or recurrence/reinfection rate among the second－fifth finger nail group, thumb nail/second－fifth toe nail group and hallux nail group. There was no obvious adverse reaction but pain during the treatment. Conclusions Long pulsed Nd:YAG laser appears to be an effective and safe approach to the treatment of onychomycosis, and the treatment outcome is affected by clinical types, location, and causative fungal species of onychomycosis. 【Key words】 Phototherapy; Onychomycosis; Treatment outcomes

Key words: Onychomycosis