The obesity epidemic is among the world’s most devastating health problems, outnumbering
starvation, and even the COVID-19 pandemic in morbidity and mortality. Although weight
loss efforts through lifestyle modifications are generally recommended, and do add
to the necessary armamentarium, they are by themselves usually insufficient. Conversely,
bariatric surgery is well established as an effective treatment, and among the alternative
methods, Roux-en-Y gastric bypass (RYGB) is still widely popular, given the current
efficacy and acceptable side-effect profile [1].
The altered upper gastrointestinal anatomy in these patients may present various endoscopic
challenges. Patients with RYGB anatomy are exposed to hepatobiliary problems, particularly
gallstone disease, because of obesity, rapid weight loss, and possibly even because
of the blind loop microflora in the excluded duodenal loop with glucuronidase-producing
bacteria. Moreover, a substantial proportion of patients present with abdominal pain
mandating gastroscopy to exclude gastroduodenal pathology [2]. Thus, endoscopic access to the excluded segment of the gastrointestinal tract is
important, but difficult.
The main options for access have been device-assisted enteroscopy (E-ERCP) and laparoscopy-assisted
access, primarily for laparoscopy-assisted endoscopic retrograde cholangiopancreatography
(LA-ERCP). Both methods are well described and effective, but also fraught with specific
challenges. The enteroscopic route to the gastroduodenum is lengthy, and requires
time, as well as special skills not widely available. Also, the peripapillary positioning
for ERCP is challenging, with acute angulation, limited tip maneuverability, and lack
of elevator for catheter manipulation. LA-ERCP, on the other hand, offers easier access
to the papilla, and a standard duodenoscope with standard accessories can be used.
It does, however, require an experienced laparoscopic surgeon for appropriate trochar
placement, along with the time, cost, and logistic challenges of a perioperative ERCP
in the operating theatre.
Endoscopic ultrasound-directed transgastric ERCP (EDGE) has emerged as an alternative
to the existing suboptimal approaches to pancreatobiliary intervention in these patients.
Placement of a temporary lumen-apposing metal stent (LAMS) into the excluded stomach
was initially described in 2014 [3], as a means of accessing the papilla through a close-to-normal route with a duodenoscope
for pancreatobiliary endoscopy. The method obviates the lengthy route and positional
challenges of E-ERCP, as well as the logistics and specific complications of LA-ERCP,
allowing an endoscopist facile in EUS and ERCP to complete the procedure within the
endoscopy unit.
Naturally, the three methods are alternatives that need comparative analysis. A recent
meta-analysis addressed the issue [4], and concluded that the technical and clinical success of EDGE is better than that
of E-ERCP and comparable to that of LA-ERCP, with adverse events (AEs) similar to
that of the laparoscopic approach. At the moment, however, available data are all
based on retrospective case series, where direct comparisons remain difficult.
The series by Kochar et al in this edition of EIO [5] is a welcome addition to the existing literature. They present a 56-patient, single-center,
4-year retrospective experience with all three methods, with 26, 18, and 12 patients
handled by EDGE, LA-ERCP, and E-ERCP, respectively. Their results mirror that of the
general literature quite well, with superior technical success with EDGE and LA-ERCP
compared to E-ERCP. Method-specific AEs were minimal in this study, but numbers were
too low for adequate comparison. The relative safety of E-ERCP suggested by a recent
meta-analysis probably still holds true [4].
More importantly, however, the authors suggest an algorithm for assigning patients
to each method, which to me makes a lot of sense at the current time. It does mandate
the availability of all three options, but that would likely often be the case in
a referral center. Their algorithm also underlines that the methods are complementary,
rather than competing alternatives. Briefly, a concomitant indication for cholecystectomy
would favor LA-ERCP, while patients with surgical anatomy amenable to E-ERCP should
be referred for that. EDGE remains reserved for patients without need for cholecystectomy
and with impossible or failed enteroscopic access.
This seems a very reasonable conclusion based on current knowledge, and counters some
single-method enthusiast reports available. It is not clear whether this algorithm
was, in fact, applied by the authors; likely it has emerged over time with increasing
experience with all methods.
While EDGE may indeed turn out to be the preferred method in this situation, questions
remain that are only partially addressed by the current paper:
For now, the method is still non-standardized, and even the report by Kochhar describes
various variants. Questions about aspects such as stent caliber, placement techniques
(need for guidewire, stent fixation, multi-step procedures), significance of complications
such as persistent fistula or stent dislodgment, and cost considerations remain open
and mandate careful consideration. With increasing general expertise in placing LAMS
for other indications, likely the rates of AE will decrease for this procedure as
well, but the specific issues of dislodgement due to endoscope traversing must be
addressed. The safest strategy appears to be a two-step procedure to allow maturation
of the tract before ERCP, if it is clinically feasible. In most situations, a separate
procedure would be needed for delayed stent removal anyway. However, urgent cases
may mandate a different strategy, and the current method may not be optimal for a
one-step procedure. Perhaps t-tag fixation of the anastomosis would be worth exploring,
or improved fixation of the LAMS? These questions need to be addressed before the
EDGE procedure is introduced into general practice. The current rate of AEs is a concern,
and expansion of the technique is likely to increase this rate further. Refinement
of the technique in the hands of experts is likely a prudent way forward.
On the other hand, EDGE has additional benefits that must be acknowledged. In particular,
with EDGE, EUS-guided procedures can be performed that would be difficult or impossible
with enteroscopy- or even laparoscopy-assisted procedures [6]. This utility further adds to the reasons for developing this EUS-based shortcut
for anatomical access.
This paper underlines the expanding role of combined EUS/ERCP utility needed in advanced
pancreatobiliary endoscopy units, and the authors are to be commended for moving the
field one more step forward in this respect.
