Review for 10.1186/s12876-025-03767-5 (2025)

Title: The usefulness of percutaneous bile duct metal stent insertion for malignant biliary
obstruction: a retrospective study
Version: 2 Date: 06 Jan 2025
Reviewer's report:
I have carefully read the article entitled "The usefulness of percutaneous bile duct metal stent
insertion for malignant biliary obstruction: a retrospective study" and believe the study holds
potential. Therefore, I would like to provide the following comments:
a) The abstract is brief and straightforward, as are the introduction and methods. I believe this
group of patients (14 patients) could be better explored! The methodology should be more
detailed, including information about the initial drainage phase, the clinical progression of
bilirubin levels, the applicability of chemotherapy, as well as other clinical variables.
b) What was the average time (in days) between the first phase and the second phase?
c) After the second phase (SEMS implantation), did the authors immediately remove the
percutaneous catheters? If not, please explain.
d) Why did you use uncovered SEMS exclusively in all patients, solely due to the occurrence
of pancreatitis? For many years, our institution has performed endoscopic drainage with fully
covered SEMS, and our acute pancreatitis rate is < 2%, confirming the results of the meta-
analysis presented in your study.
e) With endoscopic ultrasound, the results are excellent. However, the development of this
technique occurred because the percutaneous method could not, for technical reasons, place an
SEMS in a single phase. Importantly, you have demonstrated that this is possible! This was
precisely the aspect of your study that caught my attention. We have frequently discussed this
possibility with our radiologists, who have always been opposed to it, but you successfully
applied it in three patients! I would like the authors to explain the technique used in these three
patients in detail, including clinical specifics.
f) I suggest transforming this study into a more clinical investigation. Although the authors
report an absence of complications, those of us accustomed to managing these patients after
percutaneous intervention know that the presence of internal and external catheters causes
significant clinical discomfort for the patients.
g) Overall, percutaneous transhepatic biliary drainage is more suitable for hilar
cholangiocarcinoma with complex stenosis, suggesting that percutaneous stents may be useful
for hilar cholangiocarcinoma. However, in cases where guidewires can be passed to the
duodenum, this allows for the Rendez-vous technique with endoscopy for SEMS insertion in
different hepatic segments. I would like the authors to discuss this aspect further. In the same
study, the authors describe two cases of postoperative recurrence of cholangiocarcinoma but do
not provide detailed descriptions. Including these details could enrich the discussion.
h) I would like to know more details about the insertion of SEMS in a single phase, as this
method would make the percutaneous technique more appealing. I believe the authors should
explore this further, perhaps even comparing the results in a simple manner between patients
undergoing SEMS implantation in one phase versus two phases, despite the limited number of
cases described.
i) Despite the study's limitations, such as being retrospective, descriptive, and lacking
comparisons, the topic is relevant since the current preferred method is endoscopic treatment.
However, if the percutaneous technique evolves, it may become a more attractive option, even
compared to the ultrasound-guided technique.