Laser-tissue interaction in tattoo removal by q-switched lasers

Retrospective clinical evaluation of Q-switched Nd:YAG laser safety and efficacy in tattoo removal: A new perspective on the Kirby-Desai scale

BACKGROUND

With nearly 50% of the population in the United States, Italy, and Sweden tattooed with at least one tattoo, the demand for its removal has risen by 32% since 2011. Traditional removal methods, such as Q-switched (QS) laser-based tattoo removal, can be lengthy, requiring up to 20 sessions.

AIM

This study presents a retrospective clinical evaluation of seven short-pulsed QS, dual-wavelength Nd:YAG laser, as an efficient alternative, that can potentially reduce the number of sessions needed as calculated by a founded scale.

METHODS

The QS modality delivers high-intensity pulses in four wavelengths, ideal for removing multicolored tattoos, of which two were used. We studied 11 patients who underwent 3-8 treatments (average 5.09) every 2-3 months. Each tattoo was assessed using the Kirby-Desai scale, considering the following factors: location, Fitzpatrick skin type, ink amount, layering, scarring, tissue changes, and tattoo color. Follow-ups were conducted after 6 months and at 4-5 years following last session.

RESULTS

The long-term follow-up presented a significantly higher tattoo removal efficiency than the short-term follow-up (p < 0.001), indicating a sustained process of ink breakdown and elimination. Notably, the actual number of treatments were significantly lower than that predicted by the Kirby-Desai scale (average 5.09 vs. 9.9, p < 0.001). No severe adverse events were reported.

CONCLUSIONS

In conclusion, the QS Nd:YAG laser offers a safe and effective alternative for tattoo removal, requiring fewer treatments than initially expected.

Comprehensive examination of tattoo removal using a 150 ps Nd:YAG laser in a porcine model

This study aimed to investigate the efficacy of a Nd:YAG laser with a pulse duration of 150 ps at different laser parameters. The effects on multiple-colored tattoos with such ultrashort pulses has not been previously described in the literature. In vivo experiments were conducted on porcine skin to analyze the fragmentation efficiency of five different tattoo colors using different wavelengths, pulse energies, and spot sizes. The results showed that the optimal tattoo clearance to safety ratio for blue, green, red, and yellow tattoos with a 532 nm wavelength was 0.96-2.39 J/cm2. The laser with a wavelength of 1064 nm demonstrated the highest efficacy in eliminating black tattoos, with positive results observed for green and blue pigments at a fluence of 3.02 J/cm2. The study provides valuable insights into the efficacy of laser treatment with 150 ps for removing tattoos of different colors using different laser parameters. This information can help dermatologists and practitioners perform more efficient and effective tattoo removal with fewer side effects.

Q-S laser micro-drilling and multipass full-beam Q-S laser for tattoo removal - a case series

The purpose of this study was to evaluate the safety and efficacy of a new combined method of Q-S laser-assisted tattoo removal. Ten patients with 13 professional, mostly mono-chromatic black tattoos were recruited. All tattoos received the same Q-S laser treatment sequence. An objective evaluation of tattoo clearing was assessed by careful analysis of a standardized collection of digital images taken from each tattoo, 2 months after each laser session, with the help of a custom-made pigment-fading percentage photographic ruler. The percentages of pigment clearance and side effects were evaluated by 4 independent dermatologists. Patient satisfaction and perceived discomfort during and post-procedure were evaluated according to specific scales. Clinical evaluators confirmed an average photographic pigment clearance of 97% after a median 4.85 treatment sessions. The Frac-Tat® method required 40% fewer sessions compared to those calculated by Kirby-Desai estimates. Photographic assessment of laser-exposed skin quality performed 2 months after tattoo clearing was considered almost comparable with untreated peripheral skin, confirming a very low side effect score. The Frac-Tat QS laser-assisted tattoo removal sequence used in our study showed a high degree of safety and efficiency, clearing exogenous pigments in a relatively few number of sessions. Preliminary ablative photo-acoustic fractional 1064-nm Q-S laser micro-drilling was considered an essential step in optimizing tattoo removal, increasing wavelength-independent micro-columnar clearing of deeper dermal exogenous pigments. Our preliminary observations also confirmed a significant improvement of tattoo procedure-induced micro-textural changes thanks to a tissue remodeling effect induced by the 1064-nm Q-S fractional laser photo-acoustic ablation.

Q-switch nanosecond laser as innovative and instant management for bruises discoloration, a case report

Bruises is one of the most common side effects of injectable cosmetic procedures, which leads to stress to clients and health care providers. Conventional treatments such as vitamin K preparation, cold compresses, and Arnica cream have been used to treat bruises, yet these treatments do not provide instant results. The purpose of this report is to present a case in which different wavelengths of Q-switch nanosecond laser was used to treat cosmetic injection-related bruises.Four different laser wavelengths were used to treat injection-related bruises. Pictures were taken before and after the treatment and analyzed using the RGB color histogram and the Image color analyzer from http://mkweb.bcgsc.ca/. Pictures showed a close to complete resolution of the bruises and discoloration. The results of this report suggest that using multiple selective wavelengths, in shorter pulse width but higher fluence would be more effective in resolving bruise-related discoloration compared to using one wavelength with longer pulse width.

Picosecond laser versus historical responses to Q-switched lasers for tattoo treatment

BackgroundTattooing is increasingly common among adolescents and young adults. This study explores the clinical efficacy of picosecond laser for the correction of tattoos. Literature suggests that 25-47% of the population have had a tattoo at some point in their life (1). The incidence is slightly higher in adults 18-35 years (22-47%) compared to college students (18-25 years of age(1, 2). Recent surveys report 25% of tattooed adults expressing regret, while 4% of tattooed students had already undergone some form of tattoo-removal procedure (3). A common request for tattoo removal includes poorly executed tattoos, avoidance of stigmatization, trauma, socially inappropriate, and employment. Several procedures have been proposed to remove tattoos including cryosurgery, thermal cautery, or surgical resection (4). A major disadvantage of these methods is that they are all highly operator dependent, and carry a very high risk of residual scarring, residual pigment being left behind "ghosting" (3). In addition, some opt to cover the unwanted tattoo with another design, which results in layered tattoos that are substantially harder to manage. Laser surgery, in skilled hands, is an effective method for tattoo removal and traditionally, this is performed with Quality-Switched Laser, where energy liberatred in the nanosecond range results in a selective photothermal effect (5). Picosecond laser is a more recent innovation that results in energy released in a picosecond timescale (a time interval 1000 times shorter).One potential disavantage of laser therapy for the effacement of cutaneous tattoos is the length of treatment and associated cost, which might dissuade the patient from following through to completion of treatment, limiting potential benefits whilst still being exposed to risk of harm. (5, 6). Recent studies suggest that picosecond laser result in substantially reduced treatment times, whilst achieving an identical or more effective end result (7-9). However, these studies are limited by very small sample size and follow-up.

Assessment of Effects of Laser Light Combining Three Wavelengths (450, 520 and 640 nm) on Temperature Increase and Depth of Tissue Lesions in an Ex Vivo Study

Background: Lasers are widely used in medicine in soft and hard tissue surgeries and biostimulation. Studies found in literature typically compare the effects of single-wavelength lasers on tissues or cell cultures. In our study, we used a diode laser capable of emitting three components of visible light (640 nm, red; 520 nm, green; 450 nm, blue) and combining them in a single beam. The aim of the study was to assess the effects of laser radiation in the visible spectrum on tissue in vitro, depending on the wavelength and pulse width. Methods: All irradiations were performed using the same output power (1.5 W). We used various duty cycles: 10, 50, 80 and 100% with 100 Hz frequency. Maximum superficial temperature, rate of temperature increase and lesion depth were investigated. Results: Maximum superficial temperature was observed for 450 + 520 nm irradiation (100% duty cycle). The highest rate of increase of temperature was noted for 450 + 520 nm (100% duty cycle). Maximum lesion depth was observed in case of three-wavelength irradiation (450 + 520 + 640 nm) for 100, 80 and 50% duty cycles. Conclusions: The synergistic effect of two-wavelength (450 + 520 nm) irradiation was observed in case of maximum temperature measurement. The deepest depth of lesion was noted after three-wavelength irradiation (450 + 520 + 640 nm).

The effect of the perfluorodecalin patch on particle emission and skin temperature during laser-induced tattoo removal

Laser-based procedures for tattoo removals are popular due to high efficacy and a relatively moderate insult. However, it often requires multiple sessions to achieve a satisfactory effect. The perfluorodecalin (PFD) patch utilizes an optical clearing agent to speed up the removal process and may decrease skin insult and harmful particles emission during treatment. This study assessed in pigs the effect of the PFD patch in connection with laser treatment of skin with and without tattoos to determine whether the PFD patch provides benefit in lowering thermal skin insult and particle emission during treatment. Skin temperature measured by infrared thermometer during laser treatment or shortly thereafter showed a significant (approximately 40%) decrease with the PFD patch in sites with tattoos. For laser-treated sites without tattoos, there was a significant decrease of particles observed with the PFD patch. In laser-treated sites with tattoos, a strong trend was seen (approximately a twofold decrease) but did not reach statistical significance due to high variability. The present data show that the PFD patch limits the increase in skin temperature produced with laser during treatment. Moreover, it decreases the emission of particles in sites without tattoos and is suggestive of a similar effect in sites with tattoos.

Modelling of the heat accumulation process during short and ultrashort pulsed laser irradiation of bone tissue

An analytical model is presented that qualitatively describes the cooling of a biological tissue after irradiation with short and ultrashort laser pulses. The assumption that the distribution of temperature at the initial moment of surface cooling repeats the distribution of the absorbed laser energy allowed us to use the thermal conductivity approximation in both cases. The experimental results of irradiation of dry bone with nanosecond and femtosecond laser pulses are compared with the calculated data. The necessity of taking into account the change in the optical parameters of hard tissue in the field of laser irradiation during its treatment by nanosecond and femtosecond laser pulses and the key role of residual heating in its carbonization around the exposure region is shown. The application of the model to a particular biological tissue can significantly simplify the search for optimal parameters of lasers for surgical procedures.

Mini-Punch Skin Excision: A Newer Novel Approach for Tattoo Removal

Q-switched Nd:YAG laser remains the gold standard for tattoo removal, but still some tattoos are not completely removed in a specified period as desired by the patient. Herein, we present a case report of 23-year-old patient who came to the outpatient department for tattoo removal. The tattoo measured around 20cm × 18cm and was located on the back. Nine to 12 sessions of 1064-nm Q-switched Nd:YAG laser were planned at 4- to 6-week interval. After the completion of nine sessions, all the shades of the tattoo disappeared, but the lines persisted. A trial of increased laser energy and multiple-pass R20 treatment was performed, which rather increased the scarring and no improvement in tattoo clearance was noticed. We tried mini-punch skin excision for clearing the remnant tattoo lines. The tattoo was cleared successfully without significant scarring. Mini-punch skin excision is a very promising technique, similar to the follicular unit extraction technique of hair transplant, for tattoo removal of the patients who want immediate results as compared to lasers that take almost a year, provided the patient accepts the risk of scarring.

Tattoo removal by Q-switched yttrium aluminium garnet laser: client satisfaction

BACKGROUND

Tattoo removal by Q-switched yttrium aluminium garnet (YAG) lasers is golden standard; however, clients' satisfaction with treatment is little known.

OBJECTIVE

To determine clients' satisfaction with tattoo removal.

METHODS

One hundred and fifty-four tattoo removal clients who had attended the private clinic 'Centre for Laser Surgery', Hellerup, Denmark, from 2001 to 2013 completed a questionnaire concerning outcome expectations, level of pain experiences and satisfaction with tattoo removal. The laser surgeon and his team were blinded from data handling. The study design included a minimum 2-year postlaser treatment observation period from 2013 to 2015.

RESULTS

Overall, clients were satisfied with their laser treatment; 85% assessed their treatment and results to be acceptable to superb, while 15% assessed their treatment and results to be inferior to unacceptable. Effectiveness relative to colour of tattoo on a scale from 0 (no effect) to 10 (complete removal) scored a mean of blue 9.5, black 9.4, yellow 8.9, red 8.8 and green 6.5. Clients were dissatisfied with green pigment remnants, which could mimic bruising. One hundred and twenty-nine clients (84%) experienced moderate to extreme pain during treatment. Twenty-eight (20%) developed minor scarring. There were many reasons for tattoo removal; e.g. stigmatisation (33%), conspicuousness (29%) and poor artistic quality (22%). One hundred and two clients had expected complete removal of tattoos without a blemish, expectations that were only partly fulfilled. During the treatment period, clients adjusted expectations and adapted more realistic views of outcomes.

CONCLUSION

The majority of clients were satisfied with Q-switched YAG laser removal of tattoos despite high pretreatment expectations which were only partly met. The study supports YAG lasers for tattoo removal as acceptable therapy of today, with room for new approaches.