Title: Risk factors of early postoperative bowel obstruction for patients undergoing selective
colorectal surgeries
Version: 2 Date: 22 Sep 2021
Reviewer's report:
The authors explore the risk factors of postoperative bowel obstruction following colorectal
surgery and developed predictive model for its occurence.  Although it is a meaningful study,
some points related to the study are as follows.
#1. In the study, patients diagnosed with gastrointestinal perforation prior to surgery, patients
with a history of gastrointestinal surgery, and patients who had a stoma with an ectopic
or ileostomy were excluded from the study. Why were patients excluded? It would be
recommndable to include all of these patients in the analysis.
#2. Developing a model for all patients and validating the developed model with the same data
set can overestimate the predictive power of diagnosis. Consider dividing all patients in a random
2:1 ratio into a model development group and a validation group,  and then verifying the model
in the validation group after model development.
#3. Indicate the basic principles of pre- and postoperative management  during colon surgery
in this institution.
#4. Variables included in the univariate analysis are unclear and their definitions are not
specified.
#5. What does probiotic indications mean?
#6. A history of constipation is also a factor that can affect intestinal obstruction, but it is not
included.
#7. Specify the type of postoperative analgesia.
#8. The criteria for hypothyroidism are unclear, and if a patient with hypothyroidism is taking
thyroid hormone, normal thyroid function is likely to be maintained. make the definition clear.
#9. Briefly present the interpretation of the nomogram in the manuscript.
Title: Risk factors of early postoperative bowel obstruction for patients undergoing selective
colorectal surgeries
Version: 2 Date: 22 Sep 2021
Reviewer's report:
The authors explore the risk factors of postoperative bowel obstruction following colorectal
surgery and developed predictive model for its occurence.  Although it is a meaningful study,
some points related to the study are as follows.
#1. In the study, patients diagnosed with gastrointestinal perforation prior to surgery, patients
with a history of gastrointestinal surgery, and patients who had a stoma with an ectopic
or ileostomy were excluded from the study. Why were patients excluded? It would be
recommndable to include all of these patients in the analysis.
#2. Developing a model for all patients and validating the developed model with the same data
set can overestimate the predictive power of diagnosis. Consider dividing all patients in a random
2:1 ratio into a model development group and a validation group,  and then verifying the model
in the validation group after model development.
#3. Indicate the basic principles of pre- and postoperative management  during colon surgery
in this institution.
#4. Variables included in the univariate analysis are unclear and their definitions are not
specified.
#5. What does probiotic indications mean?
#6. A history of constipation is also a factor that can affect intestinal obstruction, but it is not
included.
#7. Specify the type of postoperative analgesia.
#8. The criteria for hypothyroidism are unclear, and if a patient with hypothyroidism is taking
thyroid hormone, normal thyroid function is likely to be maintained. make the definition clear.
#9. Briefly present the interpretation of the nomogram in the manuscript.
Please review this paper.
user
Title: Risk factors of early postoperative bowel obstruction for patients undergoing selective
colorectal surgeries
Version: 2 Date: 22 Sep 2021
Reviewer's report:
The authors explore the risk factors of postoperative bowel obstruction following colorectal
surgery and developed predictive model for its occurence.  Although it is a meaningful study,
some points related to the study are as follows.
#1. In the study, patients diagnosed with gastrointestinal perforation prior to surgery, patients
with a history of gastrointestinal surgery, and patients who had a stoma with an ectopic
or ileostomy were excluded from the study. Why were patients excluded? It would be
recommndable to include all of these patients in the analysis.
#2. Developing a model for all patients and validating the developed model with the same data
set can overestimate the predictive power of diagnosis. Consider dividing all patients in a random
2:1 ratio into a model development group and a validation group,  and then verifying the model
in the validation group after model development.
#3. Indicate the basic principles of pre- and postoperative management  during colon surgery
in this institution.
#4. Variables included in the univariate analysis are unclear and their definitions are not
specified.
#5. What does probiotic indications mean?
#6. A history of constipation is also a factor that can affect intestinal obstruction, but it is not
included.
#7. Specify the type of postoperative analgesia.
#8. The criteria for hypothyroidism are unclear, and if a patient with hypothyroidism is taking
thyroid hormone, normal thyroid function is likely to be maintained. make the definition clear.
#9. Briefly present the interpretation of the nomogram in the manuscript.
assistant