[Cited from: JOURNAL OF COSMETIC AND LASER THERAPY, Authors: Debora Aparecida Oliveira Modena, etc.]

Parameters and skin phototypes

The table below shows the demographics and characteristics of individuals included in the studies, such as nationality, age, skin phototype, tattoo ink, and all the main parameters used in the application of the Q-switched 1064 nm/532 nm Nd:YAG laser (www.wisoptic.com), as well as the use of local anesthetics. Most individuals were American, between 16 and 70 years old, with both black and multicolored tattoo inks.

Regarding the laser parameters, pulse duration varied from 5 to 450nm, fluency from 0.3 to 12.5 J/cm², with the point size from 2 to 10 mm, and five studies mentioned the use of anesthesias.

Adverse effects

The immediate effects of the treatment were reported by the study evaluators and included edema from light to moderate (98%), erythema (95%), bleeding (9%), and purpura (24%). Subjects reported crusting (35%) and blistering (10%), but the issues were solved without intervention before the following treatment.

Purpura was reported after a single treatment using a wavelength of 532 nm, buy was completely solved in the subsequent visit. Occasional light bleeding was ween immediately after 13.8% of the treatments, with associated edema (94%) and erythema (69.3%) occurring after most of the treatments.

Regarding pain and discomfort in the application sessions of the Q-switched 1064 nm/532 nm Nd:YAG laser, Kauvar et al. (2017) reported the average amount of pain between the 10 treatment sessions were as follows: 50% with minimal discomfort, 24% moderate discomfort and 6% with severe discomfort. In the study which carried out the application with the Nd:YAG laser in short pulse versus long pulse, the average amount of pain by the visual analog scale (VAS) was 3.8 ± 1.0 and 7.9 ± 1.0, respectively. Bernstein et al. (2013) also evaluated pain by VAS and the patients subjected to that laser type reported pain 2/10 with the use of intradermal lidocaine.

The most common adverse effects after the therapeutic application with the Q-switched 1064 nm/532 nm Nd:YAG laser were post-inflammatory hyperpigmentation, 10 cases of which were reported in the studies included in this review (five cases of hypopigmentation and five of hyperpigmentation). Besides, there were reports of a higher chance of post-inflammatory hyperpigmentation in the areas of black pigment and a higher chance of hypopigmentation in the areas of red and yellow pigmentation.

Methodology quality assessment

The six studies included in this review were evaluated for their methodological quality through the Downs and Black scale. Of the studies included in this review, the highest score was 22 points; one presented 19 points, two presented a score of 18, and two others score 17.

The higher risk of bias was observed in the sections that referred to presenting an estimate of dispersion and variability for the main results, carrying out efforts to keep individuals without knowledge about the exposure (blinding), considering the results of the participants who did not follow-up and if the participants invited and included in the study were representative of the entire population from witch they were recruited.