Review for 10.1186/s12876-018-0878-8 (2018)

Reviewer ’s report  
 
Title: Evaluation of Valve Function in Antireflux Biliary Metal Stents  
 
Version: 0 Date: 25 Feb 2018  
 
Reviewer: Hirofumi Kogure  
 
Reviewer's report:  
 
This is an interesting paper to investigate the mechanism of stent dysfunction of anti -reflux valve 
biliary stents using in vitro phantom models. This study may play an important role in 
developing anti -reflux valve biliary stents, but there is a flaw in the study plan.  
 
 
In the bile flow phantom model, all stents were removed from the device to measure the flow 
resistance every 2 weeks for 12 weeks and then placed back to the silicone tubes. However, as 
the authors mentioned, the biof ilm or sludge are easily cleared during each measurement, which 
would 'reset' or decrease the flow resistance when placed back into the silicone tube in the bile 
flow phantom model. To accurately evaluate flow resistance, the authors should have prepared 
six sets of stents and the first set should have been measured two weeks later, the second set 4 
weeks later, and so on, without returning the stent once removed.  
 
 
Although the authors disclose no conflicts of interest related to this manuscript, the staff of the 
manufacturer (M.I.Tech, Co. Ltd. ) of the stent used in this study is included in the authors. Is 
there really no conflict of interest?  
 
 
 
 
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 manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects req uire 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, f ees, 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 
financially from the publication of this manuscript, either now o r 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 compe ting 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 f or publication, my named report 
including any attachments I u pload will be posted on the website along with the authors' 
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which I do n ot wish to be included in my named report can be in cluded as confidential comments 
to the editor s, which will not be published.  
 
I agree to the open peer review policy of the journal