Review for 10.1186/s12876-017-0691-9 (2017)

Reviewer ’s report  
 
Title:  Minimally I nvasive Pancreaticoduodenectomy for Periampullary Disease: a 
Comprehensive Review of Literature and Meta -analysis of Outcomes Compared with Open 
Surgery  
 
Version: 0 Date: 25 Aug 2017 
 
Reviewer:  Fuyuhiko  Motoi  
 
Reviewer’s report:  
 
Chen K et al reported the Minimally Invasive Pancreaticoduodenectomy fo r Periampullary 
Disease: a Comprehensive Review of Literature and Meta -analysis of Outcomes Compared with 
Open Surgery. This might be an important issue in this field. However, severe limitation for the 
comparison could be pointed out.  
 
My major concern abo ut this comparison between minimal invasive (MIPD) and open PD (OPD) 
is significant selection bias. As described in the manuscript, conversion from MIPD to OPD 
varies -40%. This means that difficult case tend to be excluded from MIPD and included to OPD. 
In this situation, MIPD could not be compared to OPD about intraoperative factors, 
postoperative recovery, morbidity and mortality, and also oncological outcomes. This selection 
bias should be managed if this comparison was reported.  
 
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.  
 
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.  
 
I am able to assess the statistics  
 
Qualit y 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 w ay 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 sal ary 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 competing interests' 
below. If your reply is yes to any, please give details below.  
 
I have no competing interests.  
 
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to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal