The last years saw the dawn of a paradigm shift in small bowel investigation and management.
Once difficult to approach through both endoscopic and radiologic studies, small bowel
evaluation underwent a game-changing revolution with the recent advent of new endoscopic
and radiologic technologies. The radiologic revolution came from the development of
computed tomography enterography (CTE) and magnetic resonance imaging enterography
(MRE). The advantages over the old small bowel follow-through rapidly became evident,
as superimposed 2-dimensional bowel loops were replaced by the new multiplanar small
bowel reconstructions.
Until recently, endoscopic techniques have been very limited either in the depth of
insertion (push-enteroscopy), lack of therapeutic intervention or availability (probe-enteroscopy)
or invasiveness (intra-operatory enteroscopy). Hence, radiologic techniques have long
been the mainstay of small bowel investigation.
A little over a decade ago, another revolution in small bowel evaluation took place.
Over a few years, two new endoscopic technologies emerged independently and the evaluation
and management of small bowel pathologies have once again changed. Forever.
The first endoscopic revolution came with capsule endoscopy (CE), a disruptive technology
that rendered a once inaccessible organ at the reach of a small swallowable endoscopic
capsule.
1
Gastroenterologists have rapidly adapted to this new approach to small bowel endoscopy,
akin to Richard Fleischer's “Fantastic Voyage” from 1966 (http://www.imdb.com/title/tt0060397/).
Although CE has rapidly established its place in several diagnostic algorithms as
a noninvasive endoscopic procedure that enables total enteroscopy, its pitfalls and
limitations (mostly concerns about false negatives, lack of control and therapeutic
capability) have also arisen.
2
The second endoscopic revolution came with double-balloon enteroscopy (DBE).
3
This groundbreaking, and yet simple, adaptation of a long enteroscope to a balloon-overtube
allowed pleating of the small bowel, overcoming the main limitation to deep small
bowel endoscopic progression: the formation of small bowel loops preventing the continued
use of linear forces to push the enteroscope through the small bowel. Two other forms
of device-assisted enteroscopy (DAE) soon followed: single-balloon enteroscopy, similar
to DBE, but lacking the balloon at the tip of the enteroscope; and spiral enteroscopy,
in which a spiral-overtube is used to convert a rotational force applied to the overtube
that pleats the small bowel into a linear force that advances the enteroscope.
These technologies were also promptly conquered by endoscopists eager for a direct
endoscopic access to the small bowel. Although invasive and lengthy procedures, their
role in small bowel management became established as complementary to CE and CTE/MRE,
mostly for direct evaluation, biopsy or therapy of pathologies suspected or established
with the previous examinations.
Most standard endoscopic therapies were adapted to the small bowel therapeutic repertoire,
some after the development of dedicated accessories. Several hemostatic therapies
such as argon–plasma coagulation, clipping or injection, either in routine or emergency
settings,4, 5 have drastically changed the management of obscure gastrointestinal
bleeding. Once suffering from multiple inevitable surgeries, patients with Peutz–Jeghers
syndrome (PJS) and small-bowel polyps are currently managed almost exclusively endoscopically.2,
6 Dilation of benign stenoses, mostly Crohn's and NSAIDs strictures
7
and stenting of malignant tumors
8
are at present times also within the reach of DAE. Retained small-bowel foreign bodies
are now generally an enteroscope and a Roth-Net away
9
and direct percutaneous endoscopic jejunostomy is nowadays usually performed with
a balloon enteroscope.10, 11
Its use has rapidly expanded beyond the boundaries of the small-bowel. Once inaccessible
to endoscopic retrograde colangio-pancreatography (ERCP), patients with a surgically
modified anatomy became manageable by DAE-ERCP.
12
Its use promptly extended from diagnosis to therapy, such as stone-extraction, balloon-dilation
of bilioenteric strictures
13
or stenting with plastic or self-expandable metallic stents.14, 15 Combined rendez-vous
procedures using DAE-ERCP and percutaneous transhepatic colangiography
16
have also been reported, either to assist difficult techniques or to manage complications.
17
Furthermore, the balloon-overtubes have found a role independent from the enteroscope,
as for difficult stenting in the upper and lower gastrointestinal tract
18
or assisting difficult endoscopic submucosal dissection in the colon.
19
In this issue of GE, Kröner PT et al present a case series of yet another therapeutic
procedure enabled by DAE, small-bowel endoscopic mucosal resection (EMR).
20
The authors present a series of eight patients who underwent EMR of jejunal polyps.
An inject-and-resect technique was used after evaluation and delimitation of lesions
with FICE electronic chromoendoscopy and careful submucosal injection with diluted
epinephrine. All procedures were successful, either en bloc or in piecemeal, and no
complications were reported. The main limitation, as acknowledged by the authors,
is that this is a retrospective series of only eight patients, but so are most other
published series on new therapeutic procedures using DAE.
Although EMR in the small bowel using DAE has been previously reported and is probably
underreported in several series on the endoscopic management of PJS,2, 6 this is the
first series focusing in small bowel EMR using DAE. Moreover, apart from raising awareness
to the addition of EMR to the therapeutic armamentarium of DAE, this article from
Kröner PT et al provides important tips and tricks useful for a safe small bowel EMR.
Once again, another frontier in therapeutic enteroscopy vanishes.