The Energy Density and Treatment Times Are the Main Factors That Affect the Efficacy of Long-Pulsed 1,064-nm Nd:YAG Laser Treatment for Onychomycosis Caused by <b><i>Trichophyton rubrum</i></b>

<b><i>Background:</i></b> No optimal regimen exists for the LPNYL (long-pulsed 1,064-nm neodymium:yttrium-aluminum-garnet laser) for treating onychomycosis. <b><i>Objective:</i></b> To establish an optimal LPNYL treatment regimen for onychomycosis caused by <i>Trichophyton rubrum</i> (OCTr). <b><i>Patients and Methods:</i></b> First, 511 infected nails of 177 patients were treated using LPNYL with orthogonally designed regimens according to various energy densities, spot sizes, pulse widths, and treatment times. The optimal treatment regimen was established by multivariate analysis. Next, 69 patients with 221 infected nails were randomized to receive oral itraconazole (drug group) and the optimal regimen of LPNYL treatment (laser group). The clinical efficacy (CE) and mycological efficacy (ME) were evaluated at 6 and 12 months following the start of treatment, and adverse reactions were recorded in both groups. <b><i>Results:</i></b> Both CE and ME were significantly correlated with the energy density (<i>p</i> &#x3c; 0.05) and treatment times (<i>p</i> &#x3c; 0.05), but not with the spot size (0.071 &#x3c; <i>p</i> &#x3c; 0.083) or pulse width (0.051 &#x3c; <i>p</i> &#x3c; 0.060), at 6 or 12 months. There were no significant differences at 6 or 12 months (<i>p</i> &#x3e; 0.05), and no significant difference was observed in CE at 12 months between the two groups (<i>p</i> &#x3e; 0.05). At 6 months, the CE in the laser group was significantly higher than that in the drug group (<i>p</i> &#x3c; 0.001). <b><i>Conclusions:</i></b> LPNYL is effective and safe for treating OCTr. The energy density and treatment times are the main factors that affect the efficacy. The optimal regimen for LPNYL is an energy density of 45 J/cm², pulse width of 35 ms, spot size of 4 mm, frequency of 1 Hz, and 6 treatments with 1-week intervals. Laser treatment has rapid clinical recovery.