Review for 10.1186/s12876-018-0763-5 (2018)

Reviewer ’s report  
Title: Splash M -knife versus Flush Knife BT in the technical ou tcomes of endoscopic 
submucosal dissection for early gastric cancer: a propensity score matching analysis  
 
Version: 0 Date: 24 Dec 2017  
 
Reviewer: Wen -Lun Wang  
 
Reviewer's report:  
Comments to the Author  
 In this article, the authors reported a retrospective study to compare the hemostatic abilities of 
two knifes (Splash M -Knife vs. Flush Knife BT) for gastric ESD. They found Splash M -Knife 
achieved better hemostasis in ESD for early gastric cancer  without an increase in adverse effects. 
This may contribute to a reduction in costs by reducing the usage of hemostatic forceps during 
ESD procedure. The topic of this article is interesting, but I have the following comments.  
 
Major and specific comments : 
1. The use of hemostatic forceps during ESD procedure frequently depends on the 
endoscopists' preference, and the presence of large vessels or not, not only the hemostasis 
failure by primary knife. The setting of energy, operators' experiences, injected solution ect. 
were all the potential confounding factors. Also, the reasons for the usage of hemostatic 
forcep were not clarified and mentioned, such as whether bleeding episodes occur, 
hemostasis failure, large vessels presence etc. Thus, a non -prospectiv e, non -randomized 
study is difficult to make the conclusion.  
 
2. In this study, the procedures seem to be performed by many endoscopists. How many 
doctors performed the ESD procedures? How many operators were experts? Whether all 
operators are familial wit h and used both knifes? The information should be described in the 
text. 
 
3. In Table 2, the ESD -M group all achieved en bloc resection (100%). However, why the en -
bloc resection rate of  the ESD -M group was 95.7% after propensity score matching in 
Table 4 ? The data were not consistent.  
 
4. The definition of procedure time should be clarified. Some cases only required extremely 
short procedure time (7 minutes)? In Table 1 and Table 2, the p -value for comparisons ( 
mean and median) should be analyzed with di fferent statistic methods.  
 
5. Some important factors (ex. experiences etc.) were not shown after propensity score 
matching in Table 4.  
 
6. In discussion section (Page 16), the authors mentioned "even with these two developments, 
intra-operative bleeding remains one of the challenging problems during ESD." But these 
references cited as 22,31,32, were using flush -knife, rather than flush knif e-BT. Please see a 
new reference (Aliment Pharmacol Ther. 2010 Oct;32(7):908 -15), that showed Flush knife -
BT appears to improve haemostatic efficacy and has less bleeding points requiring 
haemostatic forceps (0 vs 3) compared with standard Flush knife.  
 
7. There are several other commonly -used needle type knifes, such as dual knife, hybrid knife, 
etc. in clinical practice. In figure 2, it shows the study institute did not use these knifes, even 
through, the flush -BT could not represent the all conventional needle type knife. So, the 
statements in the text should be modified.  
 
8. The conclusion should be modified. The authors mentioned ESD -M achieved better 
hemostasis in ESD for early gastric cancer. But the bleeding rate during the procedure was 
not describe d, and the post -procedure bleeding is similar in both groups. Thus, the less use 
of hemostatic forceps cannot totally represent a "better hemostasis". Also, "Reducing the 
usage of hemostatic forceps during this procedure" cannot totally make sure the reduc e in 
costs, because the costs of Splash M -Knife, Flush -BT, other facility were not calculated.  
 
9. Some tables were inserted in the text, but table 1 was not. These make the reading difficult.   
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.  
Yes 
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 th e manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please speci fy what  aspects require further 
assessment in your comments to the editors.  
I recommend additional statistical review  
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 
financially from the publication of this manuscript, either now or in the futu re? 
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 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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