Review for 10.1186/1471-230X-12-70 (2012)

Reviewer's report
Title:A comparison of the temporary placement of 3 different self-expanding
stents for the treatment of refractory benign esophageal strictures: A prospective
multicentre study
Version: 1Date:22 February 2012
Reviewer: Young S Oh
Reviewer's report:
Major Compulsory Revisions:
None.
Minor Essential Revisions:
1. Under the Clinical effectiveness and evaluation of dysphagia subsection,
would add “being” before “…dysphagia-free (esophageal patency)…”.
2. Under the Clinical effectiveness and evaluation of dysphagia subsection,
would add a comma between “…stent removal/dysphagia recurrence” and
“…differences were significant in the biodegradable stent group...”.
3. Under the Complications subsection, please clarify in the text that the p=0.086
refers to the difference between tissue hyperplasia with the Ella stent compared
to the other two stents.
4. In the Follow-up and reinterventions subsection, please clarify whether stent
repositioning after migration was counted as new stent placement (e.g. were
some of the 7 SEPS placed in the 3 patients after initial SEPS migration
repositioned stents that had migrated?).
5. In the Discussion section, the success rate for the van Hooft study is 60% (6
out of 10 patients had relief of their dysphagia after stent placement and
dissolution without need for reintervention) and not 70%.
6. In the Discussion section, change “alternatively” in “Alternatively, the Polyflex
stent has only 1 flared end” to “In contrast, the Polyflex stent has only 1 flared
end.”
7. In the Discussion section, change “For example, the estimated time of
dysphagia-free…” to “For example, the duration that patients were dysphagia
free after temporary stenting with a biodegradable stent or a fully covered
SEMS…”.
8. In the Statistical analysis section, consider changing the “…were compared
using the Wilcoxon signed-rank test” to “…were compared within each stent
group using the Wilcoxon signed-rank test” for clarification.
9. Please add in the Technique and stents subsection information regarding the
dilation diameter performed immediately before esophageal stent insertion. For
example, were the RBES dilated large enough only to allow passage of the stent
delivery apparatus (e.g. 12-14 mm for the SEPS, 9.4 mm for the Ella stent, 6.2
mm for the SEMS) or was another criteria was used?
10. In the Figures section, the pictures and the legends do not correspond. For
example, Figure 1 should be Figure 1 (A), Figure 2 should be Figure 1 (B), figure
4 should be Figure 2 (A), etc.
11. In Table 2, the p values of 0.27 and 0.4 are incorrectly listed as 0,27 and 0,4.
12. In the Discussion section, please discuss whether balloon dilation of the Ella
stents after deployment, which your group implemented in an attempt to mitigate
migration, did decrease migration rates compared to before balloon dilation was
implemented.
Discretionary Revisions:
1. Consider splitting the first paragraph in the Introduction section on line 20
between “…from the stents themselves [2-9]” and “To avoid complications of
partially…” since the first paragraph is quite long.
2. In the Introduction section, a brief summary (specific numbers are not
necessary since these are presented in the Discussion section) of the previously
published experience of biodegradable stents may be useful, particularly since
these stents may not be as familiar to endoscopists in countries such as the
United States where biodegradable stents are not available. As examples: (1)
The similar clinical performance and complication rates for Ella compared to
Polyflex esophageal stents as well as the significantly lower reintervention rate
for the Ella stent group in the Van Boeckel et al. study. (2) The high migration
rate of the PLLA esophageal stent (10/13 cases) reported by Saito et al. (3) Ella
stent migration rates of 2/21 (Repici et al) and 4/18 (Van Boeckel et al).
3. In the Discussion section, either add a reference to SEPS in the first sentence
of the paragraph starting with “Regarding clinical success, the results of our
study…” or combine this paragraph with the last paragraph starting with “There
are several case series that have evaluated…” since it is not initially intuitive that
the discussion is related to SEPS.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I am a consultant for the Boston Scientific Corporation. I received reimbursement
for expenses related to travel related to Boston Scientific Corporation related
business.