Incisional Hernia Following Open Pancreaticoduodenectomy: Incidence and Risk Factors at a Tertiary Care Centre

Round 1

Reviewer 1 Report

This paper entitled "Incisional hernia following open pancreaticoduodenectomy: incidence and risk factors at a tertiary care center," requires first a very extensive English revision and the following are only a few examples:

In the abstract: "analyzes". (analyses)

Line 28: Despite advancement and standardization of PD surgical technique and management of postoperative complications, morbidity and mortality rates have nowadays to 40-50% and 2-5%, respectively. Have to what?

 Line 38 :  This study was stopped prematurely due to an increase in postoperative procedure-related mortality in the laparoscopic surgery group; 10% vs. 2%.  ; punctuation!

 Line 43: Even open pancreatic surgery…. Why “even”?

 

Furthermore there are several potential flaws and areas that could be criticized. Here are some major flaws and criticisms that can be identified:

1. Lack of a comparison group: This study is a retrospective analysis of patients who underwent pancreaticoduodenectomy (PD) without a control or comparison group of patients submitted to different complex abdominal surgical procedures. This makes it difficult to assess if the reported incidence of incisional hernia (IH) in PD patients is high in comparison with other major surgical procedures or techniques. Without a control group, it is challenging to determine whether the observed incidence is specific to PD or comparable to other major abdominal surgeries.

2. Although the sample size of a total of 213 patients is not very low it is a relatively small sample size for a single center. The findings may not be generalizable to a larger population or subject to the selection bias from a single center.

3. Retrospective design: All retrospective studies introduce the possibility of incomplete or missing data, as well as potential biases in data collection. A prospective and multicentre study design would have provided more robust and reliable data.

4. Lack of standardized follow-up: The study describes follow-up procedures vaguely. It mentions that patients were followed up on a 6-monthly basis, usually with computed tomography (CT) scans and abdominal magnetic resonance imaging (MRI). However, the frequency and consistency of follow-up may vary among patients with tumor who received chemotherapy, neo- adjuvant chemotherapy or those with preoperative malnutrition potentially creating many other risk factors in a subset of patients with limited long term survival.  

5. Incomplete assessment of risk factors: The study mentions only a few potential risk factors for IH development, such as preoperative hypoalbuminemia and obesity. It does not provide a comprehensive analysis of all known risk factors associated with IH. These factors include smoking, diabetes, previous abdominal surgery, or wound complications, post-operative ileus, previous alcohol consumption and malnutrition.

The omission of these factors may limit the understanding of the multifactorial process leading to IH development in PD patients.

6. Limited discussion of limitations: The discussion does not elaborate on all the study limitations or address potential biases and confounding factors. A thorough discussion of limitations would have provided a more balanced view of the study's findings and implications.

English revision required. 

Author Response

Reviewer 1

#Reviewer 1; Comment 1: Lack of a comparison group: This study is a retrospective analysis of patients who underwent pancreaticoduodenectomy (PD) without a control or comparison group of patients submitted to different complex abdominal surgical procedures. This makes it difficult to assess if the reported incidence of incisional hernia (IH) in PD patients is high in comparison with other major surgical procedures or techniques. Without a control group, it is challenging to determine whether the observed incidence is specific to PD or comparable to other major abdominal surgeries.

Authors reply: many thanks for you comment. The main objective of this study is to analyse the factors that are related to IH incidence specifically within PD patients and therefore comparing PD patients with patients submitted to different procedures goes beyond the purpose of this study.

#Reviewer 1; Comment 2: Although the sample size of a total of 213 patients is not very low it is a relatively small sample size for a single center. The findings may not be generalizable to a larger population or subject to the selection bias from a single center.

Authors reply: thank you for your comment. We choose to use that sample size because data collection before the study time was not performed on a prospectively held database and therefore we would not increase the number of patients included due to potential quality bias. However, the statistics were adequately performed considering the number of variables analysed. We added this as a potential limitation in the Discussion paragraph.

#Reviewer 1; Comment 3: Retrospective design: All retrospective studies introduce the possibility of incomplete or missing data, as well as potential biases in data collection. A prospective and multicentre study design would have provided more robust and reliable data.

Authors reply: Many thanks. We agree with your statement, as we discuss in the Discussion paragraph, but unfortunately this is a limitation that we cannot overcome.

#Reviewer 1; Comment 4: Lack of standardized follow-up: The study describes follow-up procedures vaguely. It mentions that patients were followed up on a 6-monthly basis, usually with computed tomography (CT) scans and abdominal magnetic resonance imaging (MRI). However, the frequency and consistency of follow-up may vary among patients with tumor who received chemotherapy, neo- adjuvant chemotherapy or those with preoperative malnutrition potentially creating many other risk factors in a subset of patients with limited long term survival.

Authors reply: Many thanks for your comment. It is a policy of our center that all patients that receive pancreatic surgery are routinely followed-up in a surgical outpatient clinic on a 6-months basis by also performing a CT scan. We would not modify this policy as oncology outpatient clinic would follow-up these patients more closely, especially during the first 6 months when they receive adjuvant treatment. Patients receiving surgery for benign diseases were usually followed up in the outpatient clinic by MRI rather than CT scan. We modified the follow-up paragraph accordingly.

#Reviewer 1; Comment 5: Incomplete assessment of risk factors: The study mentions only a few potential risk factors for IH development, such as preoperative hypoalbuminemia and obesity. It does not provide a comprehensive analysis of all known risk factors associated with IH. These factors include smoking, diabetes, previous abdominal surgery, or wound complications, post-operative ileus, previous alcohol consumption and malnutrition.

The omission of these factors may limit the understanding of the multifactorial process leading to IH development in PD patients.

Authors reply: many thanks for your comment. Actually in our study we did consider smoking, diabetes, SSI and open space SSI; please find them described in the univariate analysis (table 1 and table 2). We did not consider postoperative ileus since it is difficult to differentiate it from delayed gastric emptying or other complications of CR-POPF. With regard to malnutrition, we did not perform a preoperative objective test on these patients; however, we did use hypoalbuminemia as a surrogate. Finally, the incidence of previous abdominal open surgery was very low (< 4%) in our cohort and therefore was not statistically relevant. We added these comments in the discussion paragraph.  

#Reviewer 1; Comment 6: Limited discussion of limitations: The discussion does not elaborate on all the study limitations or address potential biases and confounding factors. A thorough discussion of limitations would have provided a more balanced view of the study's findings and implications.

Authors reply: Thank you for your comment. We have extended the discussion about study limitations.

Comments on the Quality of English Language

Authors reply: Thanks for all the recommendations. All the required suggestions have been evaluated and an intensive review of English has been carried out. All modifications are notified in the “control changes” copy.

 

Author Response File: Author Response.docx

Reviewer 2 Report

There is no discussion on the possible use of a preventive mesh. I suggest you do so.

Suggested reference: 

Hernando, L. A. B., García-Ureña, M. Á., López-Monclús, J., Hernández, S. G., de Lersundi, Á. R. V., Cidoncha, A. C., ... & García, N. P. (2016). Prophylactic mesh can be used safely in the prevention of incisional hernia after bilateral subcostal laparotomies. Surgery, 160(5), 1358-1366.

It is not clear if there is a relationship between patients who suffered wound dehiscence and those wiyh incisional hernia.

I suggest you include the following reference

Brown, J. A., Zenati, M. S., Simmons, R. L., Al Abbas, A. I., Chopra, A., Smith, K., ... & Zureikat, A. H. (2020). Long-term surgical complications after pancreatoduodenectomy: incidence, outcomes, and risk factors. Journal of gastrointestinal surgery, 24, 1581-1589.

The following changes are suggested

“Despite advancement and standardization of PD surgical technique and management of postoperative complications, morbidity and mortality rates have nowadays to 40-50% and 2-5%, respectively.”

A verb seems to be missing in this sentence

“have been place in order”

Should be: Have been placed in order

“Most importantly, it can also require emergency”

Should be: Importantly, it can also require emergency

“The management of incidental hernias after open pancreaticoduodenectomy can be challenging”

Explain why is it more challenging than after other type of surgery.

“We performed a retrospective review of patients who underwent PD between 2014 and 2020 at our institution”

Please mention which is your institution.

“In this study, we demonstrated that IH occurs in 8.8%”

In this study, we found that IH occurs in 8.8%

“Life expectancy is increasing due to recent improvements in early diagnosis”

I suggest: Life expectancy is increasing due to recent improvements in early diagnosis, and increased surgical approach thanks to neoadjuvant treatment.

“IH in PD patients has not been previously evaluated in detail. Chen-Xu et al. previously demonstrated that the incidence”

IH in PD patients has not been previously evaluated in detail. Chen-Xu et al. previously found that the incidence

Author Response

Reviewer 2

#Reviewer 2; Comment 1: There is no discussion on the possible use of a preventive mesh. I suggest you do so.

Authors reply: Thank you for your comment. We did actually discuss the use of preventive mesh, please find it enclosed in the discussion paragraph.  

#Reviewer 2; Comment 2: I suggest you include the following reference

Authors reply: We have added the recommended reference.

#Reviewer 3; Comment 3: “We performed a retrospective review of patients who underwent PD between 2014 and 2020 at our institution” Please mention which is your institution.

Authors reply: Thank you. We added this to the methods paragraph according to your suggestion.

Comments on the Quality of English Language

Authors reply: Thanks for all the recommendations. All the required suggestions have been evaluated and an intensive review of English has been carried out. All modifications are notified in the “control changes” copy.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

 

The manuscript has been improved, and I acknowledge the efforts made.

However, I would like to clarify some minor concerns.

1. Please try to explain better the statement you provided ”a prospectively held database”. It seems that the Authors argue that the data for their study were extracted "prospectively” . This terminology may seem confusing because they also state that the study itself is retrospective. It is important to explain exactly what you mean by this context, a "prospectively held database". Do you mean that your database is maintained and updated in real time through ongoing data collection? Usually such databases are usually designed to capture relevant and information from a changing algorithm during routine data collection. Since the data you store in this study were pre-defined when the study was planned, it is unclear what a “prospectively held database” means. In some cases, well-organized and standardized databases for large pools of data can be shared in the same department or the same hospital for multiple units and they have a trade name. They are “big-data” platforms and have specific technology and tradename.  In summary, the use of a "prospectively held database" in the context of a retrospective study means that the data used in the study were extracted from a pre-existing, ongoing database that was initially designed to capture information in real time and extracting data when the study was decided. This point needs clarification and discussion about their potential bias since this type of predefined prospectively database cannot contain all data necessary to a medical research when a new retrospective (or prospective) study is decided.

2. Try to explain to readers what it is the rule of 4:1 which is considered the minimum to reduce IH risk. Add a specific reference (for instance Leif A. Israelsson, MD, Daniel Millbourn Prevention of Incisional Hernias How to Close a Midline Incision. Surg Clin N Am 93, 2013, 1027–1040).

3. Please clarify if post-operative recommendations of short period of physical rest and a postoperative binder was uniformly advised to all patients or not. 

Author Response

Please see the attachment

Author Response File: Author Response.docx