Introduction
Nonmalignant strictures in the upper gastrointestinal (GI) tract causing dysphagia
have significant impact on patients’ quality of life and present challenges to the
interventional endoscopist [1]
[2]. The underlying pathophysiology of benign strictures of the esophagus is mainly
increased production of fibrous tissue following an inflammatory process [3]. Stenotic processes obstructing more than 50 % of the esophageal lumen lead to the
burdening symptom of dysphagia [4].
Esophageal dilation is the standard procedure for nonmalignant strictures in the upper
GI tract. It is effective, providing symptomatic relief in 85 % – 93 % of cases [2]
[5]
[6]. The ideal technique facilitates a high degree of visibility and control ensuring
maximum safety and treatment efficiency.
Dilators include polyvinyl-wire-guided dilators (Savary-Gilliard) and balloon dilators
(wire-guided and through-the-scope [TTS]) [2]. Bougie dilators rely on tactile perception to determine the amount of resistance
encountered with passage through the esophagus under fluoroscopic control. Sequential
dilation is performed. The “rule of three” has been generally accepted but a recent
retrospective study found that nonadherence to the rule of three does not increase
the risk of adverse events [2]
[7]. TTS balloons may be used as an alternative. They are inflated to the desired amount
of dilation and then maintained in that position for 30 – 60 seconds [8]. In a prospective randomized comparison, no clear advantage in the efficiency of
using either Savary bougies or balloons could be demonstrated [9].
A major drawback for bougies is the lack of optical feedback. Success or failure can
only be evaluated by taking a second look with the endoscope. In addition, complications
cannot be prevented but only treated afterwards. TTS balloons allow real-time visualization
of the process, but provide no haptic feedback for the endoscopist, and the decision
on the appropriate diameter depends on the judgment of the endoscopist [8].
To combine the most desirable aspects of conventional techniques, a clear, tapered
cap – the BougieCap – has been developed to be fixed to the front end of an endoscope.
The new device may provide optical feedback similarly to TTS balloons and can be used
under haptic control. This might help to adjust endoscopic treatment even more precisely
to the stricture.
The aim of this prospective multicenter study was to evaluate the feasibility of endoscopic
dilation using the BougieCap and improvement of dysphagia-related symptoms in short-term
follow-up.
Methods
The BougieCap (Ovesco Endoscopy AG, Tübingen, Germany) is a disposable, clear, conical,
over-the-scope cap that can be used for endoscopic treatment of GI stenosis. The endoscope
equipped with the cap acts as a mediator for the applied radial and longitudinal force
vectors ([Fig. 1], [Fig. 2]). The device is available in several different outer diameters so that the appropriate
size can be selected by the endoscopist during first inspection of the stenosis. It
can be attached to the tip of standard and pediatric gastroscopes, and secured by
circular tape. The endoscope with the BougieCap is inserted into the esophagus and
positioned in front of the stenosis. By pushing forward, the scope – cap system is
advanced through the stricture under direct vision and bougienage is performed ( [Fig.3]). Sequential bougienage can be performed with increasing device diameter, if applicable.
If reasonable, the use of a stiff guidewire passed through the working channel and
the front hollow core of the attached cap is possible.
Fig. 1 Longitudinal cut of the BougieCap (Ovesco Endoscopy AG, Tübingen, Germany). Lateral
holes allow suction, CO2 insufflation, and water flushing. The central hole serves as a core for optional
insertion of a guidewire. Source: Ovesco
Fig. 2 Available BougieCap (Ovesco Endoscopy AG, Tübingen, Germany) sizes. a For a standard gastroscope. b For a pediatric gastroscope (10, 8, 7 mm).
Fig. 3 Endoscopic images. a Narrowing esophageal stricture. b Dilation with optical control using the BougieCap (Ovesco Endoscopy AG, Tübingen,
Germany). c Endoscopic aspect after dilation.
A prospective interventional study was conducted at three endoscopy units in Germany
(Ulm, Essen) and the United Kingdom (Southampton) between February and July 2018.
The patient sample size was 50. Individuals aged > 18 years were enrolled for study
participation if the following inclusion criteria applied: benign stenosis of the
esophagus with indication for endoscopic dilation, clinical symptoms of dysphagia,
written informed consent. Exclusion criteria were lack of agreement by the patient,
malignant stenosis or no indication for endoscopic treatment.
The primary end point was success of endoscopic dilation. Success was defined as sufficient
dilation of the stenosis in one endoscopic session with endoscopic passage after bougienage.
The secondary end point was improvement of symptoms of dysphagia. Dysphagia-associated
symptoms were assessed by the Dysphagia Handicap Index (DHI) questionnaire before
treatment (Day 0) and at short-term follow-up 14 days after bougienage (Day 14). DHI
is a 25-item patient-reported outcome measurement for assessing the handicapping effect
of dysphagia and covers physical, functional, and emotional aspects. A point-rating
scale is applied: never (0 points), sometimes (2 points), and always (4 points). Clinical
severity groups (1 – 4) are defined as normal (no symptoms; < 25 points), mild (25 – 50),
moderate (50 – 75), and severe dysphagia (≥ 75) [1].
The study was approved by the institutional review board and ethics committee of the
University of Ulm (Germany) and was registered at ClinicalTrials.gov (NTC03349021).
Written informed consent was obtained from all patients. All authors had access to
study data, and they reviewed and approved the final manuscript.
Pentax i10 (9.8 mm), Olympus GIF-H260 (9.8 mm), Olympus GIF-HQ190 or Olympus GIF-XP190N
endoscopes were used for endoscopy. The diameter of the BougieCap was chosen by the
respective endoscopists. The procedure could be terminated at the discretion of the
endoscopist, but particularly if deep tears occurred where the muscle layer was visible
or if it was subjectively felt that the resistance was too high.
Statistical tests were performed using SPSS version 24 (IBM Corp., Armonk, New York,
USA). Student’s t test and Mann-Whitney test were used wherever applicable. A P value of < 0.05 indicated statistical significance.
Results
A total of 50 patients were recruited across the three centers with a mean age of
67.1 years (range 21 – 96 years). Further patient and stenosis characteristics are
shown in [Table 1]. The most common cause of stenosis was peptic (46 %). According to UK guidelines
on esophageal dilation, all strictures were defined before treatment as complex strictures
due to narrowed diameter and failed passage with a standard gastroscope. Out of the
50 patients, 32 had undergone previous endoscopic treatment for clinically apparent
stenosis.
Table 1
Patient characteristics.
|
Patient characteristics
|
|
|
n
|
50
|
|
Sex, m/f, n
|
25 /25
|
|
Age, years
|
|
|
67.1 (16.8)
|
|
|
21 – 96
|
|
Origin of stenosis, n (%)
|
|
|
23 (46)
|
|
|
13 (26)
|
|
|
6 (12)
|
|
|
4 (8)
|
|
|
2 (4)
|
|
|
1 (2)
|
|
|
1 (2)
|
|
Location, n (%)
|
|
|
7 (14)
|
|
|
14 (28)
|
|
|
29 (58)
|
|
Diameter of stenosis before intervention, mean (SD), mm
|
7.5 (2.4)
|
|
Length of stenosis, mean (SD), mm
|
10.7 (8.6)
|
|
Previous endoscopic treatment, n
|
|
|
32
|
|
|
18
|
ESD, endoscopic submucosal dissection; EoE, eosinophilic esophagitis; SD, standard
deviation.
Endoscopic outcome
Bougienage with the BougieCap, sized accordingly to the diameter of the stenosis,
was successfully performed in 48 of the 50 patients (96 %) ([Table 2]). In two cases with narrow and longer strictures (one peptic, one post-chemoradiotherapy)
located in the lower esophagus (length 40 mm, diameter 2 mm and 3 mm, respectively),
bougienage failed due to high resistance, which caused buckling of the endoscope in
the pharynx. Bougienage was aborted and balloon dilation was performed successfully.
Table 2
Endoscopic results of bougienage using the BougieCap[1].
|
Endoscopic results
|
|
|
Successful dilation, n
|
48
|
|
No. of BougieCaps used, mean (SD)[2]
|
2.3 (0.7)
|
|
Used stiff guidewire, n
|
|
|
8
|
|
|
2
|
|
Adverse events (n)
|
|
|
2 (10, 14 mm)
|
SD, standard deviation.
1 Ovesco Endoscopy AG, Tübingen, Germany.
2 Number of BougieCaps with increasing diameter used in endoscopic session.
The mean number of sequential bougienages was 2.3. A stabilizing guidewire was used
in 10 cases, 8 of which were with a pediatric scope. Reported complications were loss
of BougieCaps in two cases. However, in these cases, BougieCaps evacuated spontaneously
with the stool. No cases of perforation or prolonged bleedings were reported ([Table 2]).
Quality-of-life assessment/dysphagia symptoms
Mean dysphagia-associated symptoms, using the DHI, decreased from 59.0 (moderate dysphagia)
to 28.6 points (mild dysphagia) over the short-term follow-up period (P < 0.001) ([Fig. 4]).
Fig. 4 The burden of dysphagia assessed by the Dysphagia Handicap Index (DHI) before endoscopic
treatment (pre) and in short-time follow-up 14 days after endoscopy (post).
Discussion
The present multicenter study revealed the technical feasibility of endoscopic treatment
of benign esophageal strictures using the BougieCap, with significant reduction in
symptoms of dysphagia over short-term follow-up.
Although conventional methods work well in relation to the dilation process, they
only provide either haptic or optical procedural control. With Savary dilators, visual
evaluation is not possible until after the treatment and the intervention cannot be
adapted to possible major complications such as perforation. With TTS balloons, visual
control may be possible, but the examiner does not experience haptic feedback.
A flexible transparent dilator mounted over a standard endoscope, the Optical Dilator
(Ethicon, Cincinnati, Ohio, USA), has previously shown successful treatment of strictures
using this concept [10]. However, the study was in a smaller select group of patients and its design only
enabled a minimum diameter of 14 mm.
The BougieCap guarantees both optical and haptic feedback while being an easy-to-use
tool for dilating stenoses of various diameters. The direct visual evaluation provides
control on endoscopic bougienage procedure and therefore might help to adjust endoscopic
treatment even more precisely to the stricture.
Several limitations of the study should be acknowledged. First, the design of the
study was a single-arm interventional study, which limits the comparability of the
BougieCap and conventional bougienage techniques. Second, the study design only allowed
short-term follow-up. It remains unclear whether similar results can be reproduced
in a long-term follow-up setting. Third, we acknowledge that the BougieCap may disconnect
during intervention, which happened twice in the present study. Nevertheless, the
size of the BougieCap allows spontaneous passage through the intestine [11]. Furthermore, to avoid loss of the cap, the circular tape has since been modified
to increase stability.
As shown twice in our study, treatment of a complex narrow lumen and longer stricture
could be challenging as a result of endoscope buckling. The short tapered design of
the BougieCap, compared with the longer tapering of a standard Savary, may not allow
for sufficient engagement of the tip within narrower stenoses. However, in both cases,
no stiff wire was used for additional guidance and straightening of the endoscope.
In those cases, the use of wire guidance may be of assistance.
Based on our present experience, we therefore conclude that the newly developed BougieCap
enables dilation of esophageal stenosis and improves patients’ dysphagia symptoms
in short-term follow-up. Hence, it might have the potential to improve conventional
endoscopic bougienage.
