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: 2 Date: 06 Mar 2020  
 
Reviewer: Andrea Tringali  
 
Reviewer's report:  
 
The authors describe an interesting comparison of 2 different metal stent configuration for the 
percutaneous palliation of malignant hilar biliary obstruction.  
 
English need to be revised  
 
METHODS.  
Were stents (both SIS and SBS) always placed intrabiliary?  If yes please clarify why 
(preservation of sphincter of Oddi function? Other reasons?)  
 
RESULTS  
Please provide more detail on the case of fatal pancreatitis. Was dilatation of the papilla 
performed or was related to the passage of guidewires and catheters  through the papilla?  
 
DISCUSSION  
Also patients with Bismuth 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 comm ent this in the discussion section.  
 
Placing stents transpapillary can facilitate endoscopic retreatment which resulted safe and 
effective in a large series (Boškoski I, Tringali A, Familiari P, Bove V, Landi R, Attili F, Perri V, 
Onder G, Mutignani M, Cos tamagna G. A 17 years retrospective study on multiple metal stents 
for complex malignant hilar biliary strictures: survival, stent patency and outcomes of re -
interventions for occluded metal stents. Digest Liver Dis 2019; 51: 1287 -1293)  
Please comment on t his and add that reference.  
Also comment that retreatment by 2 external drainage impairs quality of life  
 
"Technically, percutaneous bilateral stent placement is easier than endoscopic placement for 
hilar strictures, since the transhepatic approach is sho rter and straighter than the 
transgastroduodenal approach. Thus, the reported technical success of endoscopic approach is 
lower than that of percutaneous approach"  
This conclusion is questionable and the reported reference (n 16) refers to a study includin g only 
very  complex strictures (types III and IV). Endoscopic stenting is feasible and is applicable also 
in complex strictures (refer to Boskoski paper).  
The use of endoscopic or percutaneous approach is mainly dependent form the local expertise 
(please  add this comment and add the following reference (Dumonceau JM, Tringali A, 
Papanikolaou IS, Blero D, Mangiavillano B, Schmidt A, Vanbiervliet G, Costamagna G, Devière 
J, García -Cano J, Gyökeres T, Hassan C, Prat F, Siersema PD, van Hooft JE. Endoscopic b iliary 
stenting: indications, choice of stents, and results: European Society of Gastrointestinal 
Endoscopy (ESGE) Clinical Guideline - Updated October 2017. Endoscopy 2018; 50: 910 -930).  
 
 
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.  
 
Yes 
 
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:  
 
Needs some lang uage 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 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.  
 
Boston Scientific Corporation (Consultant)  
 
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