Review for 10.1186/1471-230X-13-15 (2013)

Reviewer's report
Title:Endoscopic large-balloon dilation alone versus endoscopic sphincterotomy
plus large-balloon dilation for the treatment of large bile duct stones
Version: 1Date:11 November 2012
Reviewer: Jan-Werner W Poley
Reviewer's report:
In this retrospective study the authors describe their experience in removal of
large common bile duct stones with the aid balloon assisted stone extraction.
Although this technique is already known for some time and remarkably safe, it is
usually performed after sphincterotomy,potentially introducing bleeding and
perforation as an additional complication. Two publications previously described
the use of balloon dilation without previous EST in cohorts/case series without an
increased complication risk compared to historical controls.
The authors describe their results in 2 cohorts extracted from a database;
between 2004 and 2008 LBD was routinely performed with EST whereas
between 2008 and 2009 without.
In total 131 patients could be included in the analysis (respectively 62 and 69
respectively). Statistical analysis revealed no difference with regards to
complications (pancreatitis, impaction, perforation) and efficacy (stone removal
with and without mechanical lithotripsy.
Although the paper is well written and attempts to address an import clinical
question in this field, some questions remain:
Methods section:
The authors should expand on the nature of their database: were patients
identified from the database using a search query or were all LBD cases
registered and analysed? Furthermore, how many ERCPs were done during this
period?
Why was the period chosen as it was? Only to create more or less equal
numbers in both groups? What happened after 2009?
Were literally all cases of LBD performed after EST and without after the
mentioned periods? This has to do with quality of the database and therefore
reliability of the data.
Were all patients with stones > 12 mm treated with LBD or were only those cases
included in whom the endoscopists thought LBD would be necessary? Were
cases of LBD performed on stones smaller than 12 mm?
Why exclude cases with BII anatomy? Principle remains the same.
How was distal extrahepatic stenosis defined? One of the most common
indications for performing LBD is a relatively narrow section of CBD
intrapancreatically compared to stone diameter and diameter of CBD.
Are data available on procedure time? It would be interesting to know how much
(if any) mechanical lithotripsy would add on the procedure.
It is pivotal for interpreting the results of this study to understand how balloon
size was chosen. Was this done primarily on either stone size or diameter of
CBD? The authors need to elaborate more on the decision making process,
preferably with (X-ray) examples
Discussion
Overall, the discussion could be a bit more concise and focus less on previous
studies and more on their own. One example is the paragraph in which bleeding
risk is discussed. This consists mainly of speculation and interpretation of
previous data and ends with the just observation that no difference was observed
in the data of the authors.
The present study is the only one published that actually compares both
techniques, this could be emphasized more in the discussion and even though
the design is not prospective, the quality of the data is the best out there.
The paragraph where balloon/stone diameter ratio is discussed partly belongs in
the results section. The conclusion sentence “Thus, the diameter….” is very
important and also probably common sense, however it is not at all clear on how
the authors arrive to this conclusion since the procedure for LBD was not
described in full detail.
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
No conflict of interest