Review for 10.1186/s12876-021-01877-4 (2021)

Reviewer’s report
Title: 
Cecal Retroflexion is Infrequently Performed in Routine Practice and the
Retroflexed View is of Poor Quality
Version: 
2 
Date: 
07 Apr 2021
Reviewer's report:
PEER REVIEWER ASSESSMENTS: 
OBJECTIVE - Full research articles: is there a clear objective that addresses a
testable research question(s) (brief or other article types: is there a clear
objective)?
Yes - there is a clear objective
DESIGN - Is the current approach (including controls and analysis protocols)
appropriate for the objective?
Yes - the approach is appropriate
EXECUTION - Are the experiments and analyses performed with technical rigor
to allow confidence in the results?
Yes - experiments and analyses were performed appropriately
STATISTICS - Is the use of statistics in the manuscript appropriate?
Yes - appropriate statistical analyses have been used in the study
INTERPRETATION - Is the current interpretation/discussion of the results
reasonable and not overstated?
No - there are minor issues
OVERALL MANUSCRIPT POTENTIAL - Is the current version of this work
technically sound? If not, can revisions be made to make the work technically
sound?
Probably - with minor revisions
PEER REVIEWER COMMENTS: 
GENERAL COMMENTS: 
The authors describe an interesting study, assessing the number of retrospective
evaluations of right colon and the accuracy of this practice in their institution.
The paper is well written and the concept is of high interest. 
However, there are several issues that should be mentioned in order to improve
the quality of the manuscript:
- The overall number of procedures analyzed is quite small. In addition, it
describes only a single-institution experience, with a possibly "endogamic" way
of act (most endoscopists from the same institutions follow similar protocols).
This should be stated in a Limitations section, as it reduces the external validity
of the results.
- In order to add a valid message for this manuscript, it would be advisable to
include a last paragraph in the Discussion, with the opinion of the authors,
recommending (or not) the retrospective review and suggesting a procedure
protocol to improve the quality of colonoscopies.
REQUESTED REVISIONS: 
The authors describe an interesting study, assessing the number of retrospective
evaluations of right colon and the accuracy of this practice in their institution.
The paper is well written and the concept is of high interest. 
However, there are several issues that should be mentioned in order to improve
the quality of the manuscript:
- The overall number of procedures analyzed is quite small. In addition, it
describes only a single-institution experience, with a possibly "endogamic" way
of act (most endoscopists from the same institutions follow similar protocols).
This should be stated in a Limitations section, as it reduces the external validity
of the results.
- In order to add a valid message for this manuscript, it would be advisable to
include a last paragraph in the Discussion, with the opinion of the authors,
recommending (or not) the retrospective review and suggesting a procedure
protocol to improve the quality of colonoscopies.
ADDITIONAL REQUESTS/SUGGESTIONS: 
Nothing else
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Declaration of competing interests
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Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
No
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes