Review for 10.1186/1471-230X-10-130 (2010)

Reviewer's report
Title:The role of colonoscopy in the management of intestinal obstruction: a
20-year retrospective study
Version: 2Date:30 July 2010
Reviewer: David Watson
Reviewer's report:
This paper is still unable to adequately address the place of colonoscopy in the
management of large bowel obstruction as it fails to report data in the context of
recognise the true denominator of all bowel obstructions presenting to the
hospital. Reviewing operation and endoscopy records means that all patients
managed non-operatively have been missed – this will be a substantial group.
Further – most of the 26,000 people having an operation and the 18,000 having
an endoscopy did not have bowel obstruction, and they are irrelevant to the
current paper. The denominator chosen by the authors is not valid.
The details re the surgery are not adequately presented, are missing a lot of
detail, and the categorization is confusing. This paper would make a lot more
sense if the authors limited their review to patients undergoing colonoscopy for
bowel obstruction, and simply review these patients in more detail. The
retrospective case note review methodology is low on the levels of evidence and
fails to adequately address the author’s hypothesis.
The authors have only evaluated colonoscopy in suspected large bowel
obstruction. The replacement of “Colonoscopy” with “endoscopy” is incomplete,
and needs to be fully addressed throughout the paper. There are many places
where this has still not been done – eg 4 times on page 5 etc.
This remains a retrospective study of 655 patients indentified from colonoscopy
and surgical records. Reference to the 26,000 and 18,000 denominators inflate
the apparent value of the data set. They should be deleted. These denominators
are not relevant. Only a small number of patients undergoing colonoscopy had a
therapeutic intervention (<10%), so the role of colonoscopy is limited – perhaps I
am seeing this differently as a surgeon. Surgeons see all of the cases with bowel
obstruction. Gastroenterologists only see a small filtered subset, and this might
explain a different point of view. In my country the surgeons do both the surgery
and the colonoscopies – I suspect this leads to a different view of the world, and
may explain the problems I am having with the authors approach to this data set.
Other comments:
1) Please delete references to small bowel obstruction from paragraphs 3 & 4 in
the introduction - the topic is large bowel obstruction.
2) The aims of the study are a problem – the change in treatment use over time
requires the use of all cases of bowel obstruction to be used as the denominator
– the authors methodology doesn’t allow this to be determined – all they can do
is describe how colonoscopy has been used in the assessment of large bowel
obstruction.
3) The interpretation of “ethical considerations” on page 6 is incorrect. Approval
refers to the study – not consent to have a procedure as part of clinical treatment.
Informed consent for a procedure prior to its use in treatment is not informed
consent to participate in a research study. The authors need to clearly state that
this study was reviewed an approved by a human clinical research ethics
committee. If this was not done, and no approval has been sought or provided
then it will be difficult to publish this paper.
4) This is a descriptive study – the statistics are not necessary – the use of
statistical testing is potentially misleading in a case noted review.
5) The new paragraph in the results on page 8 is confusing – the data could be
better summarized in a table
6) On page 9 (and table 2), “lesion biopsy” is described as an intervention – a
biopsy is part of diagnosis – it is not a therapeutic procedure – the number of
interventions is not 67/203, it is actually much less 17/203 (<10%). This has a
major impact on the conclusions re the usefulness of colonoscopy as an
therapeutic procedure.
7) the statement on page 9 – “the surgeon more please regarding pre-operational
bowel status” requires supporting data – what does this mean?
8) pg 9 – the operations described would be better described in a table.
9) pg 9 last paragraph – the reference to small bowel obstruction and the
statistical testing is non-sensical as the authors elsewhere admit that they are
using colonoscopy for large bowel obstruction.
10) pg 9 last paragraph – references to surgery rates decreasing require a
denominator of the total number of patients presenting with obstruction, including
those managed non-operatively – see above.
11) the references in the discussion etc to a randomized trial are not really
relevant and could be omitted.
12) page 13, line 5 – what is “upper gastrointestinal colonoscopy”
13) page 13, 2nd para – this new bit of discussion is very confusing
I think the authors have confused the issue in the revision process. It would be
better to identify a single clear message, well supported by data. They are trying
to claim too much significance in this paper, and would be better served, just
describing the use of colonoscopy in patients presenting with bowel obstruction.
This would lead to the following conclusions:
It has a role
The role is limited
<10% of those undergoing colonoscopy have a therapeutic intervention.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a
statistician.