Introduction
Quality parameters for colonoscopy have recently been reported. Regarding intraprocedural
indicators, a cecal intubation rate of ≥ 90 % for all colonoscopies is widely accepted
[1]
[2]
[3]
[4]; even experienced endoscopists classify up to 10 % of colonoscopies as difficult
[5]
[6]. In spiral overtube-assisted endoscopy, a manually rotatable long overtube (Endo
Ease) is used with a standard thin flexible enteroscope, and it has been widely used
for enteroscopy [7]. Spiral overtube-assisted colonoscopy achieved a cecal intubation rate of 92 % in
24 patients in whom conventional colonoscopy had failed [8]. However, the dedicated overtube is cumbersome to use and requires assistance from
a second endoscopist for its appropriate use.
The prototype novel motorized spiral endoscope (NMSE; Olympus Medical, Tokyo, Japan)
was introduced for clinical evaluation for antegrade enteroscopy in 2015 [9]
[10]. The aim of the present trial was to evaluate the feasibility and safety of the
novel motorized spiral endoscope for diagnostic colonoscopy.
Methods
A total of 30 consecutive patients with an indication for diagnostic colonoscopy who
met the inclusion criteria ([Table 1]) were enrolled in this prospective proof-of-concept single-center trial (NCT03000361
at clinicaltrials.gov). The primary outcome was whether a cecal intubation rate of
90 % or higher was achieved. Secondary outcomes were terminal ileum intubation rate,
procedure time, need for external compression, adenoma detection rate (ADR), success
rate for removal of polyps, amount of propofol needed for sedation, sedation level
and pain score, patient satisfaction score, and adverse events. Patients were recruited
from our tertiary referral center.
Table 1
Feasibility and safety of motorized spiral colonoscopy (MSC) for diagnostic colonoscopy:
patient inclusion and exclusion criteria.
|
Inclusion criteria
|
|
Screening for colorectal neoplasia
|
|
Surveillance after previous endotherapy
|
|
Positive results of colorectal cancer screening tests
|
|
Non-overt gastrointestinal bleeding
|
|
Indeterminate iron deficiency anemia
|
|
Chronic diarrhea
|
|
Indeterminate large bowel symptoms
|
|
Exclusion criteria
|
|
Age under 18 years
|
|
Known pregnancy
|
|
Poor health status (ASA classification ≥ 4)
|
|
Contraindication for sedation or standard colonoscopy
|
|
Known coagulopathy (INR ≥ 2.0, platelets < 70 /nl) or anticoagulants other than aspirin
|
|
Medical history of chronic inflammatory bowel disease or suspected bowel obstruction
|
|
Previously identified colorectal polyps/lesions with indication for endoscopic resection
|
|
Prior abdominal surgery of the mid or lower gastrointestinal tract except uncomplicated
appendectomy
|
ASA, American Society of Anesthesiologists; INR, international normalized ratio
Study device (novel motorized spiral endoscope [NMSE])
The study device consists of three main component subsystems ([Fig. 1]):
Fig. 1 The novel motorized spiral endoscope (Olympus Medical Systems Corporation, Tokyo,
Japan). a The integrated electric motor. b The flexible short spiral overtube with soft fins is attached to the rotation coupler
of the endoscope. c The novel endoscope (163 cm working length, 11.3 mm diameter at the distal tip, 3.2 mm
caliber accessory channel) is ready for colonoscopy. d The spiral rotation force is continuously measured by the system and monitored on
a display. When resistance exceeds a certain threshold, the system automatically stops
the spiral rotation.
-
a reusable endoscope with an integrated motor for rotating a short spiral overtube
component that is mounted on a rotation coupler located in the middle of the insertion
tube;
-
a motor control unit, with foot pedals and a visual force gauge; and
-
a disposable short spiral overtube, that is, a length of tubing of approximately 18 mm
in diameter with an atraumatic plastic spiral, 31 mm in diameter, bonded to its exterior.
The study device relies on rotation of the spiral component to “pleat” or “unpleat”
the bowel either on or off the insertion tube as the spiral thread rotates in a clockwise
or counterclockwise direction, respectively ([Video 1]). A visual force gauge provides the operator with a visual indication of the direction
of rotation and the size of the rotation force throughout the examination.
Video 1 Short flexible spiral overtube connected to the rotation coupler of the novel motorized
spiral endoscope (NMSE). Rotation is activated with a foot pedal switch in clockwise
(0:04 min) and (not shown) counterclockwise direction When the device is held in the
hand outside the patient, the spiral rotation moves the endoscope forward.
Endoscopy procedure
All motorized spiral colonoscopies (MSCs) were performed by two experienced endoscopists
(H.N., T.B.). The device was inserted in the colon and advanced with the assistance
of motorized clockwise spiral rotation ( [Fig.2]). Carbon dioxide insufflation was used in all colonoscopies. After reaching and
crossing the ileocecal valve, the endoscope was withdrawn using motorized counterclockwise
spiral rotation. Tissue sampling and/or treatments were performed during withdrawal
as clinically appropriate ( [Fig.3, ]
[Video 2]).
Fig. 2 View of the flexible spiral overtube in a retroflexed position in the cecum.
Fig. 3 The novel spiral endoscope is equipped with high definition white light imaging and
narrow band imaging (NBI) and is compatible with the latest generation of standard
endoscopy systems. The spiral technology stabilizes the position within the bowel
and therefore simplifies therapeutic interventions. a High definition white light image of a suspicious sessile polyp of the colon seen
during motorized spiral colonoscopy (MSC). b NBI image. c, d En bloc endoscopic mucosal resection was performed during MSC. Histopathology confirmed
R0 resection of a submucosal invasive adenocarcinoma.
Video 2 Insertion of the novel motorized spiral endoscope with active rotation of the spiral
in the forward direction (0:00 min). Easy passage through sigmoid colon and splenic/hepatic
flexure (0:17 min) to the cecum (0:50 min). Retroflexion in the cecum shows the rotating
spiral overtube (1:00 min). Easy deep intubation of ileocecal valve to the ileum (1:06 min).
During withdrawal folds of the bowel can be straightened by gently pulling the endoscope
without spiral rotation and inspection behind the folds is often easier (1:26 min).
Detection, characterization, and removal of a suspicious sessile polyp of the colon
with en bloc endoscopic mucosal resection is shown (1:38 min). The novel spiral endoscope
is equipped with high definition white light imaging and narrow band imaging. Spiral
technology stabilizes the position within the bowel and therefore simplifies therapeutic
interventions. Histopathology confirmed R0 resection of a submucosal invasive adenocarcinoma.
Statistics
Descriptive statistical methods were used to analyze the data. Data are expressed
as mean (range).
Results
Between December 2016 and January 2017, 30 patients were enrolled (13 men, 17 women;
mean age 68.9 years, range 30 – 90) ([Table 2]). The distribution of health status according to American Society of Anesthesiologists
(ASA) classification was: ASA 1, 16.7 %; ASA 2, 36.7 %; and ASA 3, 46.6 %. Among the
patients 63.3 % had undergone prior colonoscopy, at our institution (40 %) or elsewhere
(23.3 %). Diverticula were present in 13/30 patients (43.3 %); in 10/13 (76.9 %) patients
they were restricted to the sigmoid. In 6/30 patients (20 %), diverticula were considered,
at least initially, to be lumen-narrowing. The sedation level in all patients was
3 (deep sedation according to European Society of Gastrointestinal Endoscopy guideline
levels 1 – 3 [11]). The mean amount of propofol used was 305 mg (130 – 880); in 7 patients midazolam
(3 – 5 mg) was additionally used.
Table 2
Patient data in study of the feasibility and safety of motorized spiral colonoscopy.
|
Patients (Dec 2016 – Jan 2017), n
|
30
|
|
|
13
|
|
|
17
|
|
Age, mean (range), years
|
68.9 (30 – 90)
|
|
Health status (ASA classification)
|
|
|
16.7 %
|
|
|
36.7 %
|
|
|
46.6 %
|
|
Indication for colonoscopy
|
|
|
5
|
|
|
6
|
|
|
6
|
|
|
11
|
|
|
2
|
ASA, American Society of Anesthesiologists
The cecal intubation rate was 96.7 % (29/30) ( [Table 3]). One incomplete colonoscopy occurred because of an unexpected postinflammatory
stricture of the sigmoid that could not be passed with the spiral part of the colonoscope.
The terminal ileum was intubated in all successful colonoscopies. The mean total time
for insertion to the cecum was 7.1 minutes (2.4 – 18.8), with mean time to left flexure
2.8 minutes, then to right flexure 2.5 minutes, then to cecum 1.8 minutes; and the
mean total time for insertion to the ileum was 10.1 minutes (2.6 – 26.8). The mean
withdrawal time was 11.9 minutes; the minimum withdrawal time was 6.1 minutes. The
mean total procedure duration was 22.3 minutes (10.5 – 55.4). External compression
was needed in only 1 case. Ease of use had a mean rating of 1.3 on a scale of 1 (easy)
to 5 (hard).
Table 3
Procedural data in study of the feasibility and safety of motorized spiral colonoscopy.
|
Cecal intubation rate, % (n/n)
|
96.7 % (29/30)[1]
|
|
Time to cecum, mean (range), minutes
|
7.1 (2.4 – 18.8)
|
|
Ileum intubation rate % (n/n)
|
96.7 % (29 /30)
|
|
Time to ileum, mean (range), minutes
|
10.1 (2.6 – 26.8)
|
|
Withdrawal time, mean (range), minutes
|
11.9 (6.1 – 23.5)
|
|
Total procedure time, mean (range), minutes
|
20.8 (11.4 – 55.3)
|
|
Patients with diverticula, % (n/n)
|
43.3 % (13/30)
|
|
|
23.1 % (3/13)
|
|
|
20 % (6/30)
|
|
External compression during insertion, % (n/n)
|
3.3 % (1/30)
|
|
Adenoma detection rate, % (n/n)
|
46.7 % (14/30)
|
|
Total polyps per patient, mean (range), n
|
2.4 (0 – 4)
|
|
Interventions, n
|
|
|
|
9
|
|
|
5
|
|
|
6
|
|
Adverse events[2] (asymptomatic mild superficial mucosal lesion), % (n/n)
|
6.7 % (2/30)
|
|
Severe adverse events
|
0
|
1 Technical success rate: incomplete in 1 patient with diverticula and unexpected postinflammatory
stenosis of sigmoid colon.
2 Only in two patients; superficial mucosal lesions occurred without clinical symptoms
and were classified as mild, anticipated adverse events. No severe adverse events
occurred.
Adenoma detection rate was 46.7 %, and the mean number of polyps detected was 2.4
(0 – 4) with a mean maximum diameter of 10.2 mm (4 – 25). Endoscopic mucosal resection
(EMR) was successfully performed in 9/9 cases, and 5/5 patients had successful forceps
polypectomy. All other therapeutic interventions were also conducted successfully
(clipping n = 3; argon plasma coagulation [APC] n = 1; tissue sampling n = 2).
Two mild adverse events were recorded (mild superficial mucosal lesions without clinical
symptoms). In one patient a first diagnosis of ulcerating Crohn’s disease of the colon
was established and MSC was safely performed. No severe adverse events occurred. The
patients’ mean overall satisfaction score was 9.6 on a scale of 10 (very satisfied)
to 1 (not satisfied at all), and the patients’ mean pain score was 1 on a scale of
1 (no pain) to 10 (worst imaginable pain).
Discussion
Quality guideline recommendations by the European Society of Gastrointestinal Endoscopy
(ESGE) and the American Society for Gastrointestinal Endoscopy and the American College
of Gastroenterology (ASGE/ACG) demand cecal intubation rates of more than 90 % and
even 95 % for screening colonoscopies [1]
[2]
[12]. In this trial, we found a cecal intubation rate of 96.7 %, indicating a high effectiveness
of MSC in terms of completeness of examination. However, these results must be interpreted
with caution because of the nonrandomized design with a small sample size. All the
MSC colonoscopies were performed at a highly specialized endoscopic center.
Among the patients, 43 % (13/30) had colonic diverticula and 46.6 % were suffering
from severe co-morbidities (ASA 3). In our study population 20 % (6/30) of the patients
had severe diverticulosis (6/13 or 46.2 % of all patients with diverticula), with
at least initial narrowing of the lumen. In only one of these patients was passage
through an unexpected postinflammatory stricture of the sigmoid colon not possible.
The cecal intubation time does not seem to be shorter compared to standard colonoscopy.
This is probably because the motorized colonoscope can probably not be rapidly pushed
forward as can be done in easy cases of standard colonoscopy. In our feasibility trial,
the rotation function was continuously activated during insertion to avoid pushing
and to facilitate pleating parts of the large bowel onto the shaft of the endoscope.
This technique may prolong the procedural duration but could minimize loop formations.
Adenoma detection rate (ADR) was 46.6 % in the present trial. This is not inferior
to ADRs that have been published in prospective randomized trials for full-spectrum
endoscopy (43.6 %) [13] and colonoscopy with additional retroflexion in the right colon (47 %) [14]. During withdrawal of the endoscope the soft fins of the spiral overtube were used
to straighten the bowel for inspection behind flexures and folds, similarly to other,
commercially available attachable dedicated devices or balloon-assisted dedicated
endoscopes. Quality guideline recommendations demand an overall ADR of > 25 %. Although
ADR was not the primary outcome of the present trial and patients with increased risk
for colorectal polyps (i. e. undergoing surveillance after polypectomy) were included,
these findings indicate a high potential performance of MSC in terms of detection
of neoplastic lesions.
In the present trial, all the attempted therapeutic procedures including endoscopic
mucosal resections of polyps up to 25 mm in diameter were successfully performed.
The spiral overtube seems to stabilize the position of the endoscope during therapeutic
interventions in difficult positions.
All the procedures were performed with patients in deep sedation (ESGE level 3), as
requested by all the patients prior to the procedure. Interpretation of the data in
terms of patient comfort is therefore limited. However patients rated overall satisfaction
at a high mean level of 9.6 (scale 1 to 10, 10 representing “very satisfied”).
The main concern regarding the use of standard long overtubes for colonoscopy is an
anticipated higher perforation rate [15] due to the stiffness of the rigid overtube. The novel MSC system utilizes a short
overtube, with the main purpose of facilitating advancement of the scope without pushing
and thus eliminating the abovementioned anticipated risk. In contrast it has to be
emphasized that extended pushing of the scope has to be avoided during MSC. In this
trial, no severe adverse events were recorded. In two patients, superficial mucosal
lesions were seen during endoscopy without any clinical symptoms. These lesions were
anticipated and were most probably attributable to spiral rotation. However, comparable
lesions are also seen in standard colonoscopy procedures. Thus, there is no indication
that MSC has a higher risk of mucosal injury or bleeding than the standard technique.
Because of the larger caliber of the spiral overtube compared to standard colonoscopes,
anticipated strictures might be a contraindication for MSC if passage of the stricture
with the spiral portion is necessary.
This study represents the first clinical evaluation of a motorized spiral-assisted
endoscope for examination of the colon. Our data indicate that MSC is safe and effective
for diagnostic colonoscopy. It potentially offers advantages for patients and endoscopists
in terms of ease and success of intubation of the cecum and terminal ileum and it
may facilitate therapeutic interventions. Limitations of the present study include
the low number of patients and the nonrandomized uncontrolled design. Therefore, larger
randomized trials are now needed to evaluate the performance of MSC compared to the
standard colonoscopy technique.
