Review for 10.1186/s12876-021-01689-6 (2021)

Reviewer’s report
Title: 
Utility and safety of a new uneven double-lumen sphincterotome in cases
of difficult biliary cannulation
Version: 
1 
Date: 
10 Feb 2021
Reviewer's report:
The authors have answered the queries that were raised. We should note that the
study is limited by its retrospective design and a comparative arm (canula) which
is not currently used by most centers for biliary canulation.
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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?
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Are the methods sufficiently described to allow the study to be repeated?
Yes
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