Laser Removal of Cosmetic Eyebrow Tattoos with a Picosecond Laser
Round 1
Reviewer 1 Report
Dear authors, your article is very interesting because there is always a need for more data to know the outcomes and parameters in the field of laser dermatological medicine for tattoo removal.
Here are some of my comments on this manuscript
- Line 43 should be provided with a reference for the statement about relaxation time
- Was there a need for permission from a local ethics committee to collect the data?
- On line 69, it is specified to have used fluences of 0.64 - 1.12 J/cm2 for the 532 wavelengths, but in the abstract, it is stated to have used only 0,64 j/cm2; it was probably a typo.
- On line 71, it is briefly specified how the wavelength and the fluences have been chosen. It would be handy for the readers to see a flowchart showing the work-up algorithm according to skin type and how the power of the laser has been initially chosen and increased for each session.
- On line 84, it is stated to have included 98 patients in this study, the main objective is to assess the efficacy and safeness of the picosecond laser to treat eyebrow tattoos. However, of the skin type enlisted, there are phototypes V and VI that, as long are less used with this type of lasers wavelenght, are scarcely represented in the whole group (less than 4%). I doubt having such a small group included, since these patients probably have out-of-range parameters used to treat them compared to the rest. But, in any case, It would be necessary to include some graphs that may show which wavelengths have been used and how many patients have been treated for each session. Something that may easier show, according to the result aimed, the number of patients treated and who did not need further sessions and a line graph (maybe combined, as I included in this comment as an example) with the mean, the median, and the range of fluences use divided grouped by Fitzpatrick type). It could be even more helpful, if feasible and practical, to divide the results between by group colours.
- In the results, I would also ask if it is possible to know how the time from applying the tattoo influenced the number of sessions, maybe using a regression model/univariate analysis?
- In each table, I would like to know the possibility to have also enlisted the range and median values
- It would be necessary to underline the strengths and weaknesses of this study (e.g. sample collection method, small number of specific subgroups, etc.)
Finally, I would report in a clear way (still with a new table or graph) the total number of patients divided by the expected result (Correction or removal), which shows the number of side effects you
Author Response
Dear Reviewer,
Please find below a point-by-point response to the comments:
- Line 43 should be provided with a reference for the statement about relaxation time. A reference (Reiter et al) has been added for the statement of relaxation time:
See changes in the manuscript: Line 68.
- Was there a need for permission from a local ethics committee to collect the data? There was no need for permission from local ethics committee for this retrospective study. However, a written consent form was obtained from all subjects prior to the treatment including their authorization to perform the treatment and use the photos.
See changes in the Manuscript: Lines 109-110.
- On line 69, it is specified to have used fluences of 0.64 - 1.12 J/cm2 for the 532 wavelengths, but in the abstract, it is stated to have used only 0,64 j/cm2; it was probably a typo. We have modified the abstract.
See changes in the manuscript (Abstract): Line 10.
- On line 71, it is briefly specified how the wavelength and the fluences have been chosen. It would be handy for the readers to see a flowchart showing the work-up algorithm according to skin type and how the power of the laser has been initially chosen and increased for each session. Many factors can influence the laser parameters to be used (e.g., skin phototypes, visible pigments, pigment depth…) so as fluence and the wavelength were adapted to each patient, each session. Consequently, it is impossible to prove a detailed flowchart, however, we have further developed the part “2.2 Laser treatments of cosmetic eyebrow tattoos” in the Material and Methods section.
See changes in the manuscript: Lines 113-121.
- On line 84, it is stated to have included 98 patients in this study, the main objective is to assess the efficacy and safeness of the picosecond laser to treat eyebrow tattoos. However, of the skin type enlisted, there are phototypes V and VI that, as long are less used with this type of lasers wavelength, are scarcely represented in the whole group (less than 4%). I doubt having such a small group included, since these patients probably have out-of-range parameters used to treat them compared to the rest. But, in any case, it would be necessary to include some graphs that may show which wavelengths have been used and how many patients have been treated for each session. Something that may easier show, according to the result aimed, the number of patients treated and who did not need further sessions and a line graph (maybe combined, as I included in this comment as an example) with the mean, the median, and the range of fluences use divided grouped by Fitzpatrick type). It could be even more helpful, if feasible and practical, to divide the results between by group colors.
The wavelengths 532 nm and 755 nm are not suitable for phototypes V-VI due to high probability of adverse effects. We accepted to treat 4 patients since they wanted only to attenuate their cosmetic tattoo and the pigment was only black. As the groups of phototypes V and VI were low, they were excluded to the statistical analysis displayed in the Table 3.
Regarding phototypes V and VI, we added sentences in lines 233-234.
We added more information about wavelengths and fluence that we used in lines 113-121-
In line 263 we added the number of patients who required the use of 532 nm
In Table 3, we displayed the total number of sessions as a function of phototypes.
- In the results, I would also ask if it is possible to know how the time from applying the tattoo influenced the number of sessions, maybe using a regression model/univariate analysis?
We added the statistical analysis that we performed to assess the impact of tattoo age on the number of sessions on the Table 3.
- In each table, I would like to know the possibility to have also enlisted the range and median values. In the Table 3, we added to the average number of session (second column), the minimum and the maximum number of sessions.
- It would be necessary to underline the strengths and weaknesses of this study (e.g., sample collection method, small number of specific subgroups, etc.) See changes in the manuscript: Lines 343-346 and 349 to 354.
Finally, I would report in a clear way (still with a new table or graph) the total number of patients divided by the expected result (Correction or removal), which shows the number of side effects you. I am not sure to understand the comment, however, the number of patients that wanted to redo, remove or correct are showed in the table 2. The average number of laser sessions for each objective is shown in the Table 3.
Best Regards
Reviewer 2 Report
I appreciate the authors for this scientific contribution.
Please address the following comments.
Introduction:
1- Instead of the following statement, the authors need to add more updated references that the mentioned laser is effective for tattoo removal, especially with the wavelength used in this study. Reporting one initial study on 4 patients isn't enough. "A 532/1064 nm picosecond Nd:YAG laser was safely used to eliminate brown 43 and black eyebrow tattoos on four patients in an initial pilot study"
2- Replace the last sentence of the introduction with this sentence "The objective of this study was to investigate the efficiency and the safety of 755/532 nm picosecond laser for removal of eyebrow tattoos." Do not mention the number of subjects in the introduction.
3- The authors have mentioned that "Additionally, subjects were 57 asked to define their objective: totally remove their eyebrow cosmetic tattoo, correct it or 58 attenuate it to redo a new one." This statement indicates three different therapeutic goals requiring different levels and sessions of therapy. The authors need to separate the cases based on these three categories and analyze their data separately. Treatment responses and the number of required sessions are very important in this study and widely differ between subjects with each of these goals.
4- Methods line 71: add "during the next session" to "If whitening was not observed at 755 nm, the wavelength was 71 changed to 532 nm."
5- Results line 85"22 of the 98 patients had previously undergone treatments in other medical or aesthetic centers.": this is important to report the type of previous treatments these 22 people received and how they responded to the treatment of this study. How many of them were refractory to your treatment, too?
6- Results: "The predominant segment was women aged 26 to 35 years old with Fitzpatrick phototype III."
replace with the following: "The subjects predominantly consisted of women who aged between 26 and 35 years. More than 70% of the cases were Fitzpatrick prototypes II and III."
7- Line 89 of results" dissatisfaction with results." you mean after how many sessions they were dissatisfied of the results? Add the numbers. 28 dropped-off cases is too much and the causes should be clarified with details.
8- Line 102 results: "and immediate discoloration after laser shot 102 was observed in 18 patients."
Do you mean right after the first session? or several sessions? Scaling right after the laser shot causes visual misunderstanding of total discoloration while the color still remains.
9- Line 139 discussion: Delete this "which represents a good engagement rate." There are too many drop-offs than calling it a good engagement rate.
10- Line 142 discussion: "yellow pigments did not respond"
what was the intended response? total removal at one session? or certain levels of discoloration?
11- Line 155-158 discussion: Where is the data? is this result comprehended through subjective observations of the physicians?
In the latter case, you can't conclude that some color was removed earlier than the other and the change and difference are significant. Delete this if you have no documented data.
12- Line 175 discussion: "No immediate color change was observed with organic warm pigments, as 175 these are known to be more stable than mineral oxides."
did you conclude this based on your study? Do you have documented results?
Author Response
Dear Reviewer,
Please find below a point-by-point response to the comments:
1- Instead of the following statement, the authors need to add more updated references that the mentioned laser is effective for tattoo removal, especially with the wavelength used in this study. Reporting one initial study on 4 patients isn't enough. "A 532/1064 nm picosecond Nd:YAG laser was safely used to eliminate brown 43 and black eyebrow tattoos on four patients in an initial pilot study". The Introduction part has been improved by new references and further development.
See change in the manuscript: Lines 31-34, 40-51, 54-63, 69-75.
2- Replace the last sentence of the introduction with this sentence "The objective of this study was to investigate the efficiency and the safety of 755/532 nm picosecond laser for removal of eyebrow tattoos." Do not mention the number of subjects in the introduction. Done
See change in the manuscript: Line 77
3- The authors have mentioned that "Additionally, subjects were 57 asked to define their objective: totally remove their eyebrow cosmetic tattoo, correct it or 58 attenuate it to redo a new one." This statement indicates three different therapeutic goals requiring different levels and sessions of therapy. The authors need to separate the cases based on these three categories and analyze their data separately. Treatment responses and the number of required sessions are very important in this study and widely differ between subjects with each of these goals. The number of patients that wanted to redo, remove or correct are showed in the table 2. The average number of laser sessions for each objective is shown in the Table 3. Additionally, we have added a section where we propose a patient classification.
See change in the manuscript: Lines 162-193.
4- Methods line 71: add "during the next session" to "If whitening was not observed at 755 nm, the wavelength was 71 changed to 532 nm." The sentence has been reformulated.
See change in the manuscript: Lines 119-121.
5- Results line 85"22 of the 98 patients had previously undergone treatments in other medical or aesthetic centers.": this is important to report the type of previous treatments these 22 people received and how they responded to the treatment of this study. How many of them were refractory to your treatment, too? We have further developed the part about previous experience in other medical or aesthetic centers.
See change in the manuscript: Lines 37-141.
6- Results: "The predominant segment was women aged 26 to 35 years old with Fitzpatrick phototype III."replace with the following: "The subjects predominantly consisted of women who aged between 26 and 35 years. More than 70% of the cases were Fitzpatrick prototypes II and III." Done
See change in the manuscript: Lines 134-135.
7- Line 89 of results" dissatisfaction with results." you mean after how many sessions they were dissatisfied of the results? Add the numbers. 28 dropped-off cases is too much and the causes should be clarified with details. We have further developed this part.
See change in the manuscript: Lines 145-150.
8- Line 102 results: "and immediate discoloration after laser shot 102 was observed in 18 patients." Do you mean right after the first session? or several sessions? Scaling right after the laser shot causes visual misunderstanding of total discoloration while the color remains. We have further developed this part.
See change in the manuscript: Line 203-204.
9- Line 139 discussion: Delete this "which represents a good engagement rate." There are too many drop-offs than calling it a good engagement rate. The sentence has been reformulated.
See change in the manuscript: Lines 257-260.
10- Line 142 discussion: "yellow pigments did not respond" what was the intended response? total removal at one session? or certain levels of discoloration? This sentence has been clarified.
See change in the manuscript: Line 263.
11- Line 155-158 discussion: Where is the data? is this result comprehended through subjective observations of the physicians? The assumption is based on MSDS technical data of cosmetic ink suppliers, previous scientific papers assessing the impact of pigments particle size and structure on their laser removal and our observations.
See change in the manuscript: Lines 280-283.
12- Line 175 discussion: "No immediate color change was observed with organic warm pigments, as 175 these are known to be more stable than mineral oxides." did you conclude this based on your study? Do you have documented results? The sentence has been reformulated and references have been added.
See change in the manuscript: Lines 311-318
Best Regards
Round 2
Reviewer 1 Report
The article contains a significant number of patients undergoing corrective laser treatment, and it can only be for this reason alone of considerable importance in the literature.
Furthermore, the patients are pretty homogeneous in the treated group, allowing a reduction in the heterogeneity of the data and their reproducibility.
First of all, therefore, I congratulate you on what is produced with this manuscript.
The presentation of data and results could have been better and clearer, in my opinion, although sufficient.
I reiterate that a flowchart summarizing what was already well described in point 2.2 would have been appreciable for the readers.
My actual suggestions are to specify in table 3 what is meant by statistical group
Author Response
Dear reviewer,
Many thanks for your review and relevant comments.
Based on your review, A flowchart summarizing the way we selected the laser parameters has been inserted as Figure 1 (Line 107). Additionally, the Table 3 has been modified for more clarity with the meaning of statistical groups.
Kind Regard
The Authors
