The Controlling Nutritional Status (CONUT) Score for Prediction of Microvascular Flap Complications in Reconstructive Surgery

Round 1

Reviewer 1 Report

This paper is about the use of the CT angiography for perforator mapping for ALT free flap. The manuscript is well written, and the discussion and conclusions are interesting and well referenced.

However, I would like to make some comments:

-       It should be specified how long was the follow up of the patients.

-       There was not considered the radiotherapy, which is an important risk factor of complications, especially for wound dehiscence. It should be added as part of the study or as a limitation. 

-       I am not sure where does the result of p value come from in Table 2, Table 3 and Table 4, as there are 3 or 4 columns and only one statistical analysis in each row. In the description, the authors described the analysis, but still, I do not understand if the result were from comparing the groups with “no complications”, “true flap loss” or “any flap complications”. In addition, I do not find in Table 2 if there are or not statistically significant differences in the gender as the authors confirm in the line 192.

Apart from those comments, I consider this paper as a very useful study, well designed and conducted, and with interesting conclusions. Congratulations to the authors.

Author Response

Thank you for taking the time to review and improve our draft. We highly value your kind suggestions, ideas, and valuable insights.

This paper is about the use of the CT angiography for perforator mapping for ALT free flap. The manuscript is well written, and the discussion and conclusions are interesting and well referenced.

We have made the following specific corrections according to all your recommendations:

-       It should be specified how long was the follow up of the patients.

Thank you for the recommendation. We have added information regarding follow up in the Methods section (Line 156-157).

-       There was not considered the radiotherapy, which is an important risk factor of complications, especially for wound dehiscence. It should be added as part of the study or as a limitation.

Thank you for the valuable suggestion. We have made sure to include this point in the Limitation section (Line 325-327).

-       I am not sure where does the result of p value come from in Table 2, Table 3 and Table 4, as there are 3 or 4 columns and only one statistical analysis in each row. In the description, the authors described the analysis, but still, I do not understand if the result were from comparing the groups with “no complications”, “true flap loss” or “any flap complications”. In addition, I do not find in Table 2 if there are or not statistically significant differences in the gender as the authors confirm in the line 192.

Thank you for the valuable suggestion. We have included the asterisk symbols (*) and explanation subtext to Table 2, Table 3, and Table 4 to clarify the statistical significance of the comparisons between groups. We have also clarified the point on gender, it can be found in the 4^th row of Table 2.

Apart from those comments, I consider this paper as a very useful study, well designed and conducted, and with interesting conclusions. Congratulations to the authors.

Thank You again for taking the time to improve our draft! We wish You all the best!

Reviewer 2 Report

The paper is well written and is certainly interesting. There are a few queries I have.

I’m not sure why the anesthesia protocol is needed here. 

The CONUT score is important but can the authors explain why this is related to true flap loss, as this was mentioned first in the results section ? 

Can the authors explain what surgeons should do if the CONUT score was >2, should surgery be postponed, as it predicts complications as suggested by the authors. The albumin level and cholesterol can be modified but how can we modify the lymphocyte and monocyte count ? 

Author Response

Thank you for taking the time to review and improve our draft. We highly value your inquiries, ideas, and valuable suggestions.

The paper is well written and is certainly interesting. There are a few queries I have.

The following is a detailed transcript of our feedback to Your kind inquiries and suggestions:

I’m not sure why the anesthesia protocol is needed here.

Thank You for the inquiry. We included the anaesthesia protocol to avoid confounding factors and improve the reproducibility of our study, since providing the optimal anaesthesia care is crucial for preventing flap complications. We also took into consideration the fact that similar studies on the subject also include a detailed anaesthesia protocol (doi: 10.3390/nu12020562; doi: 10.3389/fmed.2020.00289).

The CONUT score is important but can the authors explain why this is related to true flap loss, as this was mentioned first in the results section ?

Thank You for the inquiry. The CONUT score was indeed important for predicting flap complications. Interestingly, while our data showed CONUT to be a reliable predictor for flap complications, it was not a reliable predictor specifically for true flap loss. It was only a reliable predictor for other flap complications, as noted in the Results section (Line 229-234 and Line 241-242). This fascinating finding and the possible explanations and implications are examined in the Discussion section (Line 281-291).

Can the authors explain what surgeons should do if the CONUT score was >2, should surgery be postponed, as it predicts complications as suggested by the authors. The albumin level and cholesterol can be modified but how can we modify the lymphocyte and monocyte count ?

Thank You for the interest in this important point.

The pathophysiology of lymphopenia and monocytopenia involves many factors, although improvement of nutritional status is likely to improve leukocyte count, as shown in some of our cited sources (DOI: 10.1097/SLA.0000000000001113 and Ulibarri et al, 2005).

Specific guidelines on nutritional intervention have been produced for different surgical populations (DOI: 10.1016/j.clnu.2017.02.013; DOI: 10.1213/ANE.0000000000002743). We believe these guidelines are likely applicable in microvascular flap surgery, and postponing may be beneficial in select cases, although further studies are needed.

Given the observational nature of our data and our focus on assessment of malnutrition risk, it would unfortunately be beyond the scope of our study to make recommendations on specific intervention. However, we do believe that action must be taken, and further studies are needed for specific guidelines on preoperative decision making in the case of malnutrition for microvascular flap surgery. We have made sure to reinforce this point in our Discussion section (Lines 331-333). Due to the importance of this point for future studies we have made sure to point it out in our Conclusions section (Lines 336-338) as well.

Thank You again for taking the time to review our draft! We wish You all the best!