Introduction
Fully-covered self-expandable metal stents (FCSEMS) are frequently used in clinical
practice for treatment of both malignant and benign conditions along the gastrointestinal
tract [1 ]. Although effective, FCSEMS tend to migrate when they fail to imbed in the gastrointestinal
wall. Indeed, migration of FCSEMS has been reported in up to 35 % of cases [2 ]
[3 ]. Consequently, different approaches for anchoring FCSEMS have been used, including
through-the-scope (TTS) and over-the-scope (OTS) clips, as well as endoscopic full-thickness
suturing, with variable success [4 ]
[5 ]
[6 ]. A specifically designed over-the-scope fixation device (Stentfix OTS Clip System,
AG-Tuebingen Germany) to prevent stent migration has recently been introduced. It
consists of a nitinol clip preloaded on an applicator cap to clip the flared end of
FCSEMS to the intestinal wall. To our knowledge, only scant data are available on
the use of such a device [7 ]
[8 ]. We report a multicenter experience.
Patients and methods
Patients
The study enrolled consecutive patients treated with FCSEMS for different diseases
in the gastrointestinal tract, and the novel OTS Clip device was used to anchor SEMS
to the intestinal wall. These included patients with benign diseases at increased
risk of migration or with malignant diseases in whom an oncologic (chemotherapy or
radiotherapy) therapy was planned. Technical success was defined as successful positioning
of the fixation device. A liquid diet was initiated on the first day after stent placement,
then progressively advanced as tolerated. Antibiotics were administrated after the
procedure in patients with fistulas or leaks. In all patients with an esophageal stent,
a proton pump inhibitor was administered orally. Opioid analgesic drugs were administered
for 24 hours to manage pain or discomfort. Patients were followed to assess success
and delayed adverse events (AEs). Stent migration was documented at X-ray or endoscopy.
All patients provided a signed consent for the procedure, and to anonymously use their
data for scientific purposes.
Procedure
All procedures were performed by experienced endoscopists using deep sedation with
propofol or general anaesthesia administered by an anesthesiologist. FCSEMS diameters
and lengths were selected according to characteristics of strictures, fistulae or
perforations. Correct stent placement was verified by fluoroscopic examination. The
endoscope was withdrawn and the stent fixation clip device was mounted onto the tip
of the endoscope. The proximal edge of the stent was visualized and the clip tooth
rows were aligned parallel to the stent opening so that the luminal tissue and stent
mesh were evenly captured. The clip was released and a second fluoroscopic examination
was performed to reconfirm stent position. For patients who underwent esophageal stent
placement, esophagography was obtained the following day to verify position and degree
of expansion. Additional esophagrams were scheduled 1 week later and then monthly
thereafter. In patients with SEMS placed transrectally, follow-up endoscopy was performed
at 24 hours and 7 days following placement.
Device
The Stentfix OTS Clip System (AG-Tuebingen Germany) is a clip mounted in a cap positioned
on the tip of endoscope and deployed as other OTS Clip devices ([Fig. 1 ]). It was specifically designed (fish mouth shape) for anchoring to the gastrointestinal
wall without obstructing food passage. The cap has a depth of 7 mm and an oval shape.
This modified cap shape can easily be positioned parallel to the stent opening so
that stent mesh and tissue can be evenly captured using suction at the stent flange,
fixing approximately 5 to 6 mm of both stent and bowel wall. The compact design of
the device also allows passage through a stent lumen of at least 16-mm diameter. Thus,
stent fixation is possible proximally, distally, or both ([Fig. 2 ]). Clip removal can be achieved using a dedicated system (remOVE DC cutter, OVESCO),
which allows the use of direct current (DC) impulse bipolar generator pulse. This
DC pulse is applied to the OTS clip via the DC Cutter instrument introduced through
the working channel of the endoscope, allowing localized melting and cutting of the
clip. The clip is grasped with the DC Cutter instrument preferably at the thinnest
parts and repeated at a point on the clip opposite the first cut. Extraction of the
fixation device is performed using grasping forceps, in combination with a special
cap (remOVESecureCap, OVESCO). Images of this device are shown in [Fig. 3 ].
Fig. 1 Stentfix OTS Clip System (AG-Tuebingen Germany). The clip OTS Clip preloaded on the
applicator cap in an open state.
Fig. 2 a The device. b Positioning of the remOVE DC cutter on the clip bow. c Application of the current impulse to cut the clip.d The cut clip.
Fig. 3 Endoscopic image of Stentfix OTS Clip clipping stent mesh proximally and tissue to
anchor a stent to treat an esophago-jejunal anastomotic leak.
Results
The clinical and demographic characteristics of the 31 treated patients are shown
in [Table 1 ]. Data were collected from patients treated between December 2019 and April 2021
who consented to undergo the procedure and to publication of their anonymized information.
The number of patients enrolled in the four participating centers ranged from five
to 12 cases. The stent was positioned in the esophagus (cervical: 7; medium: 7; distal:
5), esophago-gastric (N = 2) and esophago-jejunal (N = 4) anastomosis, antro-duodenal
(N = 1), duodenum (N = 2), and across a rectal anastomosis (N = 3). The fixation device
was positioned at the index stent placement in 21 patients, and after previous stent
migration in the remaining 10. The stent was fixed at the proximal end in 26 patients,
at the distal side in four patients with cervical esophagus placement, and both proximal
and distal ends in one case in the colon ([Fig. 3 ]).
Table 1
Clinical characteristics of patients.
Characteristic
Finding
Male/female
26/5
Mean age ± SD; years
68.6 ± 10.7
Gastrointestinal site
28
3
Indication
14
10
5
2
SD, standard deviation.
Placement of the fixation device was technically successful in all cases (100 %).
No AEs were observed. The one migration occurred 3 days after placement in the patient
with an antro-duodenal stent, which was fixed at the proximal side, accounting for
a 3.2 % (95 %CI 0–9.4) rate of stent migration. This occurred in a patient with abundant
ascites due to peritoneal carcinomatosis and the high pressure likely contributed
to increase peristalsis. The FCSEMS was removed at various intervals, depending on
the underling disease and the general condition of patient (nutritional status, expected
prognosis). In detail, it was removed at 16 weeks (1 patient), 12 weeks (10 patients),
8 weeks (5 patients), 6 weeks (1 patient), and 4 weeks (2 patients). Ten patients
died before removal, and one case is still being followed up. No late adverse events
were observed.
Discussion
SEMS positioning along the gastrointestinal tract is widely performed to endoscopically
treat patients with fistula, perforation or stenosis [1 ]
[2 ]
[3 ]
[4 ]
[5 ]
[6 ]
[7 ]
[8 ]. SEMS placement is both technically and clinically successful in a high percentage
of cases. Unfortunately, FCSEMS tend to migrate due to lack of embedment, combined
with peristalsis. The majority of stent migrations occur within the first month after
placement [9 ], which is generally earlier than necessary to allow healing of underlying lesions.
To prevent migration, partially-covered stents can be used as the bare ends anchor
the stent by embedding into the tissue. However, their removal can be difficult. Traditional
through-the-scope (TTS) clips have been used to anchor FCSEMS. While technically easy
to place, the force exerted by these clips is low and they tend to detach quickly
and are not effective in preventing migration [4 ]
[5 ]
[6 ]. Endoscopic suture systems have been used, although they are technically more difficult
to place and expensive [9 ].
The OTS stent fixation device is novel and specifically designed for anchoring SEMS
to the gastrointestinal wall, although data on its use are scarce [7 ]
[8 ]. Unlike classical OTS Clip, this device has two grooves in the circumference, which
allow a better adherence between the stent and bowel wall, resulting in correct capture
of both edges with the clip [7 ]. We previously reported on the stent fixation device for anchoring FCSEMSs in patients
at increased risk of stent migration, due to either position or a prior migration
[7 ]. A high technical success rate was seen in both upper and lower gastrointestinal
tracts. This finding was confirmed in the present, large study in which stent migration
was observed in only one case (3.2 %). Of note, a recent study found SEMS migration
in two of 24 patients (8.3 %) treated with the same fixing device [3 ]. This compares to the 13 % reported with stent fixation using TTS clips [2 ], and 6.7 % in a pilot study of naïve patients [10 ] or 15 % in patients who experienced previous stent migration after use of a standard
OTS Clip [5 ]. Moreover, a 16 % stent migration rate was observed following endoscopic suturing
[6 ], and in as many as 35 % of cases without any fixing procedure [2 ]
[3 ]. Data from a small cases series showed that stent fixing was successfully performed
in patients with esophageal neoplastic stenosis by using classical OTS Clip for anchoring
the SEMSs [11 ]. However, in as many as 11 patients either partially-covered or long covered SEMS
were anchored, while a fully-covered stent was fixed in only one patient. Anchoring
a fully-covered stent – as we used in our case series – with classical OTS Clip might
be more difficult than using the novel device. Of note, data from an experimental
study showed that OTS Clip compression was significantly stronger as compared with
either TTS clip and suturing system [12 ].
The main limitation of our study was the lack of a comparator group. However, when
considering the very low migration rate observed by using this system, we believe
there is an advantage over other fixation devices.
Conclusions
In conclusion, this novel stent fixation device seems to be a safe and effective endoscopic
tool for anchoring FCSEMS.
