Review for 10.1186/1471-230X-9-1 (2009)

Reviewer's report
Title:Usefulness and safety of 0.4 percent sodium hyaluronate solution as a
submucosal fluid cushion for endoscopic resection of colorectal mucosal
neoplasms: A prospective multi-center open-label trial
Version: 1Date:2 May 2008
Reviewer: Greger Lindberg
Reviewer's report:
This is a multi-centre case series of patients undergoing EMR in which the
authors have used submucosal injections of sodium hyalorunate to achieve
separation of a mucosal lesion from the muscle layers of the colonic bowel wall.
It is reported as a study of feasibility and safety but there is no comparison group,
and this makes it difficult to judge the true merits of the described technique. The
presentation leaves a number of unanswered questions that I think need to be
addressed before deciding whether or not this manuscript merits publication.
Major compulsory revisions:
1. Please explain the logistics of the study. It is unclear to me a) how patients
were recruited to the study, b) at which time patients were informed about the
experimental nature of the procedure. On page 6 the authors state that informed
consent was obtained from 44 patients. Had all these patients already undergone
a previous diagnostic colonoscopy? Usually when one sees a neoplastic lesion
during colonoscopy, the lesion will be taken out in the same session. How was
such a situation treated in the study?
2. The primary outcome measure is unclear. On page 8 the authors write "The
primary outcome measure was assessed by comprehensively evaluating en bloc
complete resection…and the lifting and maintaining of a mucosal lesion during
endoscopic resection…(Table 1)". Table 1 indicates that the primary endpoint is
a kind of score along two dimensions: completeness of en bloc resection AND
need for additional injections (if that is what count stands for in the table). Then
the authors define "usefulness rate" as the percentage of en bloc complete
resections that needed a maximum of 1 additional injection. The usefulness rate
corresponds to the sum of percentages with total evaluations being Excellent or
Good. Which one of these measures was considered as the primary outcome
measure?
3. The report on the size of the study is difficult to understand. The authors state
that the a "sample size of 35 patients was required in order to bound the
hypothesized rate of resection with 95% confidence interval". What do you
mean? In fact any sample with more than 2 observations can yield a 95%
confidence interval. Since the measure is a proportion, the size of the study will
mainly affect the width of the 95% confidence interval. Please explain why 35
patients were needed! What was it that you wished to achieve by including 35
patients rather than 70 or 90 or any other number?
4. The discussion contains no comparative data. The only place I could find
some kind of comparative data was in the description of statistical methods
where the authors state that injections with normal saline enables en bloc
resection in 72.9%-85% of cases. This is an interesting figure with which the
results of this study should be compared. I think this information should be
included somewhere in the discussion. Is the "usefulness rate" of the present
study any better?
5. The discussion mainly repeats some of the results but I find very little
discussion of findings in relation to results from other studies. I also find very little
reasoning of what the findings from the present study should lead up to. Should
we use sodium hyalorunate rather than hypertonic saline or any other injection
fluid in the future?
Minor essential revisions:
6. Results/Table 2. Age is usually not a normally distributed variable. It would be
better to give the median and the range.
7. Discussion. The reasoning in the beginning of the discussion includes a
statement "Endoscopists often could not adequately lift and maintain lesions…"
that lacks verification or a reference. If the authors have data on other types of
injections this would have been interesting for the reader. Please, rephrase or
add reference.
Level of interest: An article of importance in its field
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.
Declaration of competing interests:
I declare that I have no competing interests