Review for 10.1186/s12876-022-02466-9 (2022)

Title: Fully covered self-expandable metal stent for intraprocedural or late-diagnosed Type-II
endoscopic retrograde cholangiopancreatography-related perforations
Version: 0 Date: 16 Jun 2022
Reviewer's report:
The authors retrospectively evaluate the usefulness of fully covered self-expanding metal
stenting (FCSEMS) for treating Type-II perforations. They revealed that the length of hospital
stay in the FCSEMS group was significantly shorter than that of the conventional follow-up
group. However, there was no statistically significant difference between the subgroups of
simultaneous FCSEMS and late FCSEMS. FCSEMS during and after procures might be a safe
and effective treatment modality for patients with Type-II perforation. I have several comments
for the authors.
Major
1. The authors used 40mm and 60mm-lengths FCSEMS in this study. How did the authors select
the length of FCSEMS, 40mm or 60mm?
2. Did the authors conduct ERCP under CO2 insufflation?
3. Didn’t the authors administer prophylactic antibiotics after ERCP procedure routinely?
4. Didn’t the authors use naso-gastric tube after perforation?
5. Six patients had previously undergone sphincterotomy. What were the causes of Type-II
perforations not associated with EST in these 6 patients?
6. My concern is pancreatitis after FCSEMS placement. Pancreatitis was observed in 7 patients.
What were the severities of pancreatitis in these 7 patients?
7. In page7, the authors mentioned that “As cannulation was impossible in one patient who
developed perforation during the precut, simultaneous FCSEMS could not be used.” and
“Perforation was detected after the procedure in this patient”. I consider that perforation was
detected during the procedure in this patient. Please confirm and revise.
8. The authors conducted CT with oral opaque contrast agent in the patients whose abdominal
pain did not improve. Is oral opaque agent is useful in the diagnosis of perforation and for the
decision of treatment? I am concerned that oral opaque agent leaking into retroperitoneal space
might worsen the infection.
9. The authors performed rescue FCSEMS placement in 10 patients. Was it not difficult to
perform biliary cannulation after perforation? What were the procedure time of rescue FCSEMS
placement in these 10 patients?
10. The duration of FCSEMS placement was 6 to 62 days in this study. How did the authors
decide the timing of FCSEMS removal? What is appropriate timing of FCSEMS removal in the
treatment for Type-II perforations.
11. How did the authors decide the timing of oral intake after they detected and treated
perforation? Did these patients discharge when the authors confirm no inflammation findings in
blood and physical examinations after administration of oral intake?
12. The information of Figure1 and Figure2 might not be necessary.
13. Will the author treat all patients with Type-II perforations using FCSEMS when they detect
the perforation after ERCP-related procedures according to the results of this study?
Minor
1. All abbreviations should be defined in footnotes of Tables and Figure legends.
2. There are blanks in the line of “previous ERCP history” in Table1.
3. Both mean and median “Age” might not necessary in Table1 and Table3.
4. Both mean and median “Length of stay” might not necessary in Table2 and Table3.