## 4 Clinical Indications
### Striae Distensae
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Authors** & **Type of Study** & **Number of Patients** & **Type and Location** & **Skin** & **Type of** & **Number** & **Treatment** & **Results** \\ \hline \multirow{4}{*}{[PERSON] et al. [22]} & \multirow{2}{*}{clinical trial} & \multirow{2}{*}{20} & rolling-type acne & \multirow{2}{*}{1-V} & Alexandrite (\(\frac{\text{75}}{\text{nm}}\) wall) & \multirow{2}{*}{6} & \multirow{2}{*}{\begin{tabular}{c} \text{spot size 6 mm;} \\ fluence (\(\frac{\text{71}}{\text{cm}}\))/ \(\text{cm}^{2}\)} \\ repetition rate 5 kHz; \\ pulse width 750 ps \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} significant \\ improvement in skin \\ technique, high patient \\ validation; increase in \\ fibers in the skin \\ \end{tabular} } \\ \hline \multirow{4}{*}{[PERSON] et al. [23]} & \multirow{4}{*}{\begin{tabular}{c} a prospective \\ randomized \\ clinical study \\ \end{tabular} } & \multirow{2}{*}{23} & rolling-type acne & \multirow{2}{*}{III-IV} & \multirow{2}{*}{\begin{tabular}{c} \text{alseandrite} \\ scores, boxcar seans, lucgruk scars, flavor \\ \end{tabular} } & \multirow{2}{*}{3} & \multirow{2}{*}{\begin{tabular}{c} spot size 6 mm; \\ fluence (\(\frac{\text{71}}{\text{cm}}\)/ \(\text{cm}^{2}\)), \\ diffractive lens array \\ \end{tabular} } & \multirow{2}{*}{4-6} & \multirow{2}{*}{no data} & \multirow{2}{*}{\begin{tabular}{c} improvement in skin \\ tolerance level \\ after the last session \\ \end{tabular} } \\ \hline \multirow{4}{*}{[PERSON] et al. [24]} & \multirow{4}{*}{case report} & \multirow{4}{*}{3} & rolling-type acne & \multirow{2}{*}{III-IV} & \multirow{2}{*}{\
\begin{tabular}{c} \text{alseandrite} \\ (\frac{\text{75}}{\text{nm}}\) wall with \\ diffractive lens array \\ \end{tabular} } & \multirow{2}{*}{4-6} & \multirow{2}{*}{no data} & \multirow{2}{*}{
\begin{tabular}{c} improvement in skin \\ tolerance level \\ after the last session \\ \end{tabular} } \\ \cline{1-1}  & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Studies showing the effects of using picosecond lasers to treat acne scars. ployed ablative fractional lasers to treat striae. These lasers yield promising therapeutic results but their application is associated with a risk of complications such as prolonged post-inflammatory hyperpigmentation, especially in case of the eCO2 laser, with higher energy settings, and in patients with darker skin phototypes [28]. Non-ablative lasers, such as the erbium-glass (Er:Glass 1540 nm) and the Nd:YAG 1064 nm, have also proven to be effective in striae therapy. They offer an alternative to the ablative lasers as they are associated with reduced invasiveness and shorter recovery time. The picosecond laser, which induces microscopic tissue damage, is the most recent non-ablative fractional laser with a diffractive lens array or holographic fractional technology [32; 33]. Currently, the picosecond laser, which induces microscopic tissue damage, represents the most recent development in non-ablative fractional lasers utilizing a diffractive lens array or holographic fractional technology [34]. [PERSON] et al. [35] used a fractional PS Nd:YAG laser (1064 nm) to reduce mature, atrophic striae located on the breasts, abdomen, and buttocks of Caucasian women, who underwent four treatment sessions at monthly intervals. The Global Aesthetic Improvement Scale (GAIS) and optical evaluation of the skin structure via 3D imaging, at baseline and 6 months post-treatment, were used to assess the efficacy of the therapy. Additionally, reflectance confocal microscopy was employed to evaluate microscopic changes in the skin after the therapy. An overall improvement (GAIS) was reported by 81.4% of the physicians and 66% of the patients. The findings of 3D imaging revealed significant improvement in skin texture and striae depth. These results were corroborated by confocal microscopy, which indicated collagen remodeling and formation of new dermal papillae.