Review for 10.1186/s12876-025-03973-1 (2025)

Title: Clinical outcomes of endoscopic retrograde cholangiopancreatography after Billroth II
anastomosis: A comparison of gastroscope and duodenoscope
Version: 1 Date: 12 Apr 2025
Reviewer's report:
1. The sample size was small (45 cases in the gastroscopy group and 34 cases in the
duodenoscopy group), especially in the complication analysis (3 cases in the gastroscopy group
vs. 0 cases in the duodenoscopy group), and the statistical power was insufficient, which may
lead to class II errors (false negatives). It was suggested that the statistical validity calculations
should be supplemented or that this limitation be explicitly emphasized in the discussions. If
possible, the sample size can be scaled up or multicenter collaboration can be performed to
improve the reliability of the results.
2. Retrospective design may lead to selection bias (e.g., endoscopic type selection may
be affected by the anatomical difficulty of patients). It is recommended to supplement the
comparison of baseline characteristics (e.g., anastomotic angle, intestinal loop length, etc.)
between the two groups to rule out confounding factors. Explain why cap-assisted gastroscopy
or duodenoscopy was chosen (was it chosen at random or based on surgeon preference?). ), and
discuss its impact on the outcome.
3. Although all operations were performed by three experienced endoscopists, there was no
mention of the differences between the surgeons (such as the success rate and complication rate
of different surgeons). It is advisable to supplement the analysis of inter-operative consistency
(e.g., Kappa values) or to indicate whether a standardized protocol should be used.
4. "Intubation time" is defined as "the time from the first successful intubation to the successful
intubation of selective bile ducts", but it is not clear whether it includes the time to adjust the
position of the endoscope. Operational details need to be added to improve repeatability.
5. The operation time was shorter (median about 10 minutes), which was significantly shorter
than that of previous studies (e.g., 37.7 minutes). It is necessary to discuss whether the early
termination of the operation leads to a low success rate and analyze the impact on the outcome.
6. One case of perforation (2.2%) and two cases of pancreatitis (4.4%) occurred in the
gastroscopy group, while there were no complications in the duodenoscopy group. Although
there was no statistically significant difference, the clinical significance is of concern. It is
recommended to discuss whether duodenoscopy is easier to avoid tissue injury due to structural
advantages (e.g., side-view lens, forceps lifter) in conjunction with the literature.
7. The conclusion emphasizes that "the duodenoscopy intubation time is shorter", but there is
no difference in the power of the two components, and the clinical value of the shortened time
(such as whether to reduce the risk of pancreatitis) needs to be further discussed.
8. It is recommended to supplement the cost-benefit analysis (such as the impact of equipment
cost and operation time on resource occupation) to support the conclusion that duodenoscopy
is better.
9. A number of studies were cited in the discussion section, but the reason why the SBC success
rate of this study (73.6%) was lower than that reported in the literature (81.3%-96.7%) was not
fully explained. In-depth analysis should be carried out in combination with early intraoperative
termination and teamwork mode (e.g., immediate intervention in interventional radiology).
10. It is recommended to compare the assistive technologies used in other studies (such as
balloon assist and double-mirror combination) to explore the innovation and limitations of this
study.
11. Figure 1-4 is mentioned in the text, but the content of the chart is not provided. Make sure that
the charts clearly label key data (e.g., flowcharts, complication distribution) and are consistent
with the text description.