Review for 10.1186/s12876-020-01428-3 (2020)

Reviewer ’s report  
 
Title: Pancreatic duct guidewire placement for biliary cannulation as a risk factor for stone residue 
after endoscopic transpapillary stone removal  
 
Version: 0 Date: 29 May 2020  
 
Reviewer:  Naminatsu  Takahara  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
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Please overwrite this text when adding your comments to the authors.  
 
Thank you very much for offering me the opportunity to review the paper by Dr. Fujita et al. I read 
with interest their paper of "Incidence and risk  factors of residual bile duct stones 
after extraction  by endoscopic  retrograde  cholangiopancreatography". Unfortunately, 
this paper requires substantial improvements before it is suitable for publication. Please see my 
comments below.  
 
Major comments;  
 
1. Please provide the patient flowchart in a figure to help understanding how the authors 
generate this study cohort.  
2. Please clarify how to diagnose CBD stone before ERCP in this cohort. Table 1 shows 
that 11.9% of patients required IDUS to detect CBD ston e.  
3. In addition, please clarify the follow -up strategy after ERCP. Do the authors routinely 
perform CT or MRI to check residual stones in all patients within 2 months? If the indication of 
these imaging modality is limited in cases with clinical symptom s or abnormal blood 
examinations, it is difficult to detect asymptomatic cases with residual stones, resulting in the 
underestimate the incidence of residual stones.  
4. Please offer the incidence of post ERCP pancreatitis both in the P -GW and the non -P-
GW groups.  
5. Please discuss about the risk of P -GW left in place during all through the procedure. 
Early pancreatic stent placement after GW insertion can be associated with the reduced incidence 
of PEP as well as residual stones (Hakuta R et al. J Gastroen terol Hepatol. 2019;34:1116 -22). 
 
Minor comments;  
1. Please provide the information on the gallbladder stones because it is significantly 
relevant to biliary events.  
2. Please clarify how to select several devices (balloon, basket, lithotripy) for stone 
removal.  
3. Please modify the Table 3. It is unnecessary to show the total number of each group in 
every lines.  
 
 
 
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 manus cript or would you recommend an additional 
statistical review?  
If an additiona l statistical review is recommended, please speci fy 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:  
 
Needs some  language corrections before being published  
 
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 financial ly from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation t hat may in any way gain or lose 
financi ally 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 organiz ation 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 th e 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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