Reviewer’s report
Title:  Classification of the Cystic Duct Patterns and Endoscopic Transpapillary Cannulation of the
Gallbladder to Prevent Post-ERCP Cholecystitis
Version: 0 Date: 30 Dec 2018
Reviewer: Young Koog Cheon
Reviewer's report:
General Comments:
PTGBD is commonly performed when cholecystectomy may not be utilized in elderly patients with
multiple comorbidities at a high risk of cholecystectomy. Recently, EUS-guided GB drainage has been
performed as an alternative method of PTGBD. However, EUS-guided GB drainage requires expertise
from endoscopists and the rate of complications is high. If GB drainage may be performed using
natural anatomy in patients who can not go through operations, cholecystitis may be treated effectively
while reducing the complication rate. In this regard, this manuscript is meaningful in which it showed
the anatomy of cystic duct to perform GB drainage through ERCP.
Comments 
1. Selection of the guide wire according to the type of cystic duct, 
2. The overall complication rate by the cannulation of the cystic duct should be described under
Results. Also, the difference in complication rates according to the type should be included. To find the
orifice of the cystic duct, CBD should be injected with sufficient contrast agents.
3. There is a concern that excessive injection of contrast agents into the CBD may cause or exacerbate
cholangitis. What are the authors' opinions on this issue?
4. Cholecystitis may become more severe if GB drainage may not be performed due to the failure of
cystic duct cannulation following the injection of contrast agents to the GB when finding the cystic
duct. A description is required for the actions taken in this case.
5. In Discussion, tips from the authors for successful cannulation according to the type of cystic duct
seems important. Thus, technical tips should be provided under Discussion.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you recommend an additional
statistical review?
If  an  additional  statistical  review  is  recommended,  please  specify  what  aspects  require  further
assessment in your comments to the editors.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1. Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this
manuscript, either now or in the future?
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose
financially from the publication of this manuscript, either now or in the future?
3. Do you hold or are you currently applying for any patents relating to the content of the
manuscript?
4. Have you received reimbursements, fees, funding, or salary from an organization that holds
or has applied for patents relating to the content of the manuscript?
5. Do you have any other financial competing interests?
6. Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If
your reply is yes to any, please give details below.
I declare that I have no competing interests.
I agree to the open peer review policy of the journal. I understand that my name will be included on my
report to the authors and, if the manuscript is accepted for publication, my named report including any 
attachments I upload will be posted on the website along with the authors' responses. I agree for my 
report to be made available under an Open Access Creative Commons CC-BY license 
(http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments which I do not wish to 
be included in my named report can be included as confidential comments to the editors, which will not
be published.
I agree to the open peer review policy of the journal
Reviewer’s report
Title:  Classification of the Cystic Duct Patterns and Endoscopic Transpapillary Cannulation of the
Gallbladder to Prevent Post-ERCP Cholecystitis
Version: 0 Date: 30 Dec 2018
Reviewer: Young Koog Cheon
Reviewer's report:
General Comments:
PTGBD is commonly performed when cholecystectomy may not be utilized in elderly patients with
multiple comorbidities at a high risk of cholecystectomy. Recently, EUS-guided GB drainage has been
performed as an alternative method of PTGBD. However, EUS-guided GB drainage requires expertise
from endoscopists and the rate of complications is high. If GB drainage may be performed using
natural anatomy in patients who can not go through operations, cholecystitis may be treated effectively
while reducing the complication rate. In this regard, this manuscript is meaningful in which it showed
the anatomy of cystic duct to perform GB drainage through ERCP.
Comments 
1. Selection of the guide wire according to the type of cystic duct, 
2. The overall complication rate by the cannulation of the cystic duct should be described under
Results. Also, the difference in complication rates according to the type should be included. To find the
orifice of the cystic duct, CBD should be injected with sufficient contrast agents.
3. There is a concern that excessive injection of contrast agents into the CBD may cause or exacerbate
cholangitis. What are the authors' opinions on this issue?
4. Cholecystitis may become more severe if GB drainage may not be performed due to the failure of
cystic duct cannulation following the injection of contrast agents to the GB when finding the cystic
duct. A description is required for the actions taken in this case.
5. In Discussion, tips from the authors for successful cannulation according to the type of cystic duct
seems important. Thus, technical tips should be provided under Discussion.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you recommend an additional
statistical review?
If  an  additional  statistical  review  is  recommended,  please  specify  what  aspects  require  further
assessment in your comments to the editors.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1. Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this
manuscript, either now or in the future?
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose
financially from the publication of this manuscript, either now or in the future?
3. Do you hold or are you currently applying for any patents relating to the content of the
manuscript?
4. Have you received reimbursements, fees, funding, or salary from an organization that holds
or has applied for patents relating to the content of the manuscript?
5. Do you have any other financial competing interests?
6. Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If
your reply is yes to any, please give details below.
I declare that I have no competing interests.
I agree to the open peer review policy of the journal. I understand that my name will be included on my
report to the authors and, if the manuscript is accepted for publication, my named report including any 
attachments I upload will be posted on the website along with the authors' responses. I agree for my 
report to be made available under an Open Access Creative Commons CC-BY license 
(http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments which I do not wish to 
be included in my named report can be included as confidential comments to the editors, which will not
be published.
I agree to the open peer review policy of the journal
Please review this paper.
user
Reviewer’s report
Title:  Classification of the Cystic Duct Patterns and Endoscopic Transpapillary Cannulation of the
Gallbladder to Prevent Post-ERCP Cholecystitis
Version: 0 Date: 30 Dec 2018
Reviewer: Young Koog Cheon
Reviewer's report:
General Comments:
PTGBD is commonly performed when cholecystectomy may not be utilized in elderly patients with
multiple comorbidities at a high risk of cholecystectomy. Recently, EUS-guided GB drainage has been
performed as an alternative method of PTGBD. However, EUS-guided GB drainage requires expertise
from endoscopists and the rate of complications is high. If GB drainage may be performed using
natural anatomy in patients who can not go through operations, cholecystitis may be treated effectively
while reducing the complication rate. In this regard, this manuscript is meaningful in which it showed
the anatomy of cystic duct to perform GB drainage through ERCP.
Comments 
1. Selection of the guide wire according to the type of cystic duct, 
2. The overall complication rate by the cannulation of the cystic duct should be described under
Results. Also, the difference in complication rates according to the type should be included. To find the
orifice of the cystic duct, CBD should be injected with sufficient contrast agents.
3. There is a concern that excessive injection of contrast agents into the CBD may cause or exacerbate
cholangitis. What are the authors' opinions on this issue?
4. Cholecystitis may become more severe if GB drainage may not be performed due to the failure of
cystic duct cannulation following the injection of contrast agents to the GB when finding the cystic
duct. A description is required for the actions taken in this case.
5. In Discussion, tips from the authors for successful cannulation according to the type of cystic duct
seems important. Thus, technical tips should be provided under Discussion.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you recommend an additional
statistical review?
If  an  additional  statistical  review  is  recommended,  please  specify  what  aspects  require  further
assessment in your comments to the editors.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1. Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this
manuscript, either now or in the future?
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose
financially from the publication of this manuscript, either now or in the future?
3. Do you hold or are you currently applying for any patents relating to the content of the
manuscript?
4. Have you received reimbursements, fees, funding, or salary from an organization that holds
or has applied for patents relating to the content of the manuscript?
5. Do you have any other financial competing interests?
6. Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If
your reply is yes to any, please give details below.
I declare that I have no competing interests.
I agree to the open peer review policy of the journal. I understand that my name will be included on my
report to the authors and, if the manuscript is accepted for publication, my named report including any 
attachments I upload will be posted on the website along with the authors' responses. I agree for my 
report to be made available under an Open Access Creative Commons CC-BY license 
(http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments which I do not wish to 
be included in my named report can be included as confidential comments to the editors, which will not
be published.
I agree to the open peer review policy of the journal
assistant