Review for 10.1186/s12876-020-01316-w (2020)

Reviewer ’s report  
 
Title: Percutaneous stent placement for malignant hilar biliary obstruction: side -by-side versus  
stent -in-stent technique  
 
Version: 3 Date: 18 Apr 2020  
 
Reviewer: Andrea Tringali  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload as attachments annotated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which canno t be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
 
Tha authors provided a detailed point by point reply but some points need to be included in the 
manuscript.  
Please provide a track changes version for an easier evaluation  
 
1.Reviewer 1 ：Were stents (both SIS and SBS) always placed intrabiliary? If yes  please clarify 
why (preservation of sphincter of Oddi function? Other reasons?)  
Response:  
Thank you very much for your comments. In this study, the stents wer e not always  placed 
intrabiliary. The stents were placed across the sphincter of Oddi when the lower  part of the 
common bile duct was involved. It is better to avoid placing a stent across  the sphincter of Oddi 
if the stricture is only at the hilum, because we believe that it can  reduce the reflux of duodenal 
contents and decreases the risk of cholangitis.  
 
PLEASE ADD THIS CONCEPT IN THE METHODS SECTION  
 
3.Reviewer 1 ：Also patients with Bismu th III and IV stricture were included, but only 2  stents 
were inserted obtaining an incomplete biliary drainage. Subsequent cholangitis  can be related to 
the presence of undrained ducts? Please comment this in the  discussion section.  
Response ： 
Many thanks for your comment. According to your comments and Ref 16, We have  added this in 
the Discussion section, line 10 -12, page 14.  
PLEASE ADD A COMMENT IN THE DISCUSSION SECTION CONCERNING THE 
IMPORTANCE OF DRAINAGE OF ALL OPACIFIED DUCTS TO REDUCE THE RISK OF 
CHOLANGITIS WHICH DID NON HAPPEN IN YOUR PATIENTS WITH TYPE III AND IV 
STRICTURES RECEIVING 2 STENTS ONLY  
 
4.Reviewer 1 ：Placing stents transpapillary can facilitate endoscopic retreatment  which resulted 
safe and effective in a large series. Please comment o n this. Also  comment that retreatment by 2 
external drainage impairs quality of life.  
 
Response ： 
Thank you very much for your comments. For the convenience of endoscopic  reintervention, it is 
better to place the stents transpapillary. However, this is not  mandatory for the percutaneous 
transhepatic reintervention. New stents could be  successfully placed in the old stents in most 
cases via the PTBD method.  
Nevertheless, in the real situation, some patients or their families are unwilling to  receive stents 
again considering the stents' cost (some patients have no medical  insurance), stent reocclusion, 
and patients' general status.  
 
The new reference (Ref. 16) has been added.  
PLEASE ADD THIS POINT IN THE DISCUSSION SECTION. COSTS CAN LIMIT THE 
TYPE OF TREATMENT. THIS IS A VERY IMPORTANT ISSUE IN PATIENTS IN 
COIUNTRIES WITH A PRIVATE HEALTH SYSTEM. PLEASE COMMENT ALSO THAT 
INTERNAL STENTS AND ENDOSCOPIC RETREATMENT HAVE A POSITIVE IMPACT 
ON THE QUALITY OF LIFE (Sorry I'm endoscopist!!!)  
 
 
Are the methods appropriate and well described?  
If not, please s pecify 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.  
 
Not relevant  to this manuscript  
 
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 t his 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 applie d 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.  
 
Consultant for Boston Scientific Corp  
 
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