Review for 10.1186/s12876-020-01323-x (2020)

Reviewer ’s report  
 
Title: Comparison between transpancreatic sphincterotomy and needle -knife fistulotomy in  
difficulty biliary access, a retrospective study in Taiwan  
 
Version: 2 Date: 22 Dec 2019  
 
Reviewer's report:  
 
In this study the authors aimed to assess and compare the outcomes of transpancreatic 
sphincterotomy (TPS) and needle -knife fistulotomy (NKF) for difficult biliary cannulation.  
 
The main limitation of this study is the small number of pat ients included and the retrospective 
design that limits the possibility to draw any conclusion about these procedures.  
 
1. It is hard to believe in such a standard protocol for cannulation (5 contacts with the papilla or 
more than 10 minutes of cannulation ) in a retrospective study. On the other hand, it seems that 
PEP prophylaxis needs to be standardized at your hospital.  
 
2. You stated that "Choice of TPS or NKF depended on endoscopists' judgment". So, there were 
patients who received NKF even if the panc reatic duct was cannulated? If the endoscopist prefers 
the TPS he searched voluntarily for the pancreatic duct cannulation?  
 
3. Moreover, when NKF was performed in patients with previously cannulated pancreatic duct, 
the NKF was performed with the guidewire  placed into the pancreatic duct? If yes, in how many 
cases?  
 
4. Why the 18 patients with failure cannulation were excluded? Didn't they undergo TPS or NKF 
attempt? Why these patients didn't follow the protocol for cannulation?  
 
5. It seems that 3 patients u nderwent NKF after TPS. These patients should be excluded.  
 
6. Other factors (e.g., fully covered stent or ERCP indication) should be evaluated to assess 
factors associated with PEP.  
 
7. Which was the incidence of PEP in successful cannulated patients?  
Minor:  
- In Table 2 some p values are missing.  
- Please add caption in tables to explain acronyms.  
 
 
 
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
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:  
 
Not suitable for publication unless extensively edited  
 
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 com peting 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  
 
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on my report to the authors and, if the manuscript is accepted for publication, my named report  
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I agree to the open peer review policy of the journal