Review for 10.1186/1471-230X-14-164 (2014)

Reviewer's report
Title:Endoscopic-ultrasound-assisted transmural cholecystolithotomy after
placement of a novel, fully covered metal stent: initial feasibility study using a
porcine model
Version:3Date:3 July 2014
Reviewer: Manuel Perez-Miranda
Reviewer's report:
This is an experimental study developed on in vivo swine model demostrating the
feasibility of endoscopic creation of a cholecystogastric fistula by means of
EUS-assisted deployment of a fully covered metallic stent. The authors state that
this fistula allows further endoscopic therapy within the gallbladder. The article is
well written and presented, the methods and results are correctly explained and
discussed. Thus it would deserve publication although the study has some flaws
that should be clarified before potential publication:
• The authors emphasize that after creation of this fistula cholecystolithotomy is
feasible. However this has not been proved in this study since the authors only
performed extraction of soft food material from the gallbladder. Probably
gallstones would be much more difficult to retrieve because of its hardness and
even a fistulous caliber of only 1 cm could be not enough to allow gallstone
extraction. In this sense, I think that this study actually proves the feasibility of the
endoscopic creation of a cholecystogastric fistula allowing further extraction of
the gallstones or other endoscopic therapy within the gallbladder as the authors
say in the discussion. Thus, in my opinion the title and objective of the article
should be changed and focused to emphasize not the cholecystolithotomy but
the creation of a fistula allowing endoscopic therapy. Something like “EUS
assisted transmural cholecystogastrostomy fistula creation as a bridge for
endoscopic internal gallbladder therapy using a novel fully covered metal stent”.
• Although this is a relatively novel approach, the study essentially replicates prior
similar animal studies by at least three different groups Only one such study is
referenced by the authors (Binmoeller & Shah, 2011). Furthermore, clinical
application of this novel approach has been reported by several groups (see
below). The authors should include all these references and comment on the
differences and similarities between their findings and these prior reports. The
concept of intervention through the mature, naked fistula as opposed to through
the stent intervention is novel articles, although the article by Chen et al in which
treatment of a gallbladder polyp through a cholecistogastric fistula is described
should be mentioned and discussed.
• Several types of metal stents have been used by differente authors for
EUS-guided gallbladder drainage. Their authors should provide comparative
details between their new stent (is this a prototype?) and stents used by other
authors for this purpose.
• Clinically irrelevant gallbladder leakage during dilation of the fistula is described
in all animals. Could the authors add some hypothesis of how to avoid this
leakage in the discussion?
• According to the information provided in the article it seems that all
cholecystogastric fistulas were closed when the animals were euthanized. Is that
true? How do they explain the discrepancy regarding fistula patency with prior
published studies?
• Please, complete the information of the cystotome used for dilation: caliber,
brand, etc.; where the procedures also performed under fluoroscopy?
Consider comment on:
Widmer J, Alvarez P, Gaidhane M, Paddu N, Umrania H, Sharaiha R, Kahaleh
M. Endoscopic ultrasonography-guided cholecystogastrostomy in patients with
unresectable pancreatic cancer using anti-migratory metal stents: A new
approach. Dig Endosc. 2013 Sep 18. doi: 10.1111/den.12163. [Epub ahead of
print] PubMed PMID: 24102709.
Itoi T, Binmoeller K, Itokawa F, Umeda J, Tanaka R. Endoscopic
ultrasonography-guided cholecystogastrostomy using a lumen-apposing metal
stent as an alternative to extrahepatic bile duct drainage in pancreatic cancer
with duodenal invasion. Dig Endosc. 2013 May;25 Suppl 2:137-41. doi:
10.1111/den.12084. PubMed PMID: 23617665.
Chen YY, Su PY, Shen WC. Gallbladder polyp treated with endoscopic
polypectomy through a cholecystogastrostomy. Endoscopy. 2011;43 Suppl 2
UCTN:E88-9. doi: 10.1055/s-0030-1255983. Epub 2011 Mar 18. PubMed PMID:
21425024.
Moon JH, Choi HJ, Kim DC, Lee YN, Kim HK, Jeong SA, Lee TH, Cha SW, Cho
YD, Park SH, Jeong S, Lee DH, Isayama H, Itoi T. A newly designed fully
covered metal stent for lumen apposition in EUS-guided drainage and access: a
feasibility study (with videos). Gastrointest Endosc. 2014 Jun;79(6):990-5. doi:
10.1016/j.gie.2014.02.015. Epub 2014 Apr 12 PMID: 24721518 [PubMed - in
process]
Saftoiu A, Vilmann P, Bhutani MS.Feasibility study of EUS-NOTES as a novel
approach for peroral cholecysto-gastrostomy. Chirurgia (Bucur). 2013
Jan-Feb;108(1):62-9. PMID: 23464772 [PubMed - indexed for MEDLINE] Free
Article
de la Serna-Higuera C, Pérez-Miranda M, Gil-Simón P, Ruiz-Zorrilla R,
Diez-Redondo P, Alcaide N, Sancho-del Val L, Nuñez-Rodriguez H. EUS-guided
transenteric gallbladder drainage with a new fistula-forming, lumen-apposing
metal stent. Gastrointest Endosc. 2013 Feb;77(2):303-8. doi:
10.1016/j.gie.2012.09.021. Epub 2012 Dec 1. No abstract available. PMID:
23206813 [PubMed - indexed for MEDLINE]
Teoh AY, Binmoeller KF, Lau JY. Single-step EUS-guided puncture and delivery
of a lumen-apposing stent for gallbladder drainage using a novel cautery-tipped
stent delivery system. Gastrointest Endosc. 2014 May 13. pii:
S0016-5107(14)01307-8. doi: 10.1016/j.gie.2014.03.038. [Epub ahead of print]
No abstract available.