Introduction
Ultra-thin caliber endoscopes (UTCEs) were designed for transnasal esophagogastroduodenoscopy,
with possible enhanced patient tolerability and safety. A UTCE can be used easily
in unsedated patients as a diagnostic tool, which is particularly useful for critically
ill patients and in outpatient clinics. A UTCE can also be used to evaluate a variety
of conditions, such as abdominal pain, dysphagia, dyspepsia, heartburn, and odynophagia
[1]. In addition, both screening and surveillance of Barrett esophagus and gastric cancer
are possible in an ambulant setting, without sedation, as is detailed examination
of the nasopharynx, oropharynx, and hypopharynx. As a therapeutic tool, a UTCE can
aid in the placement of feeding tubes or percutaneous endoscopic gastrostomy (PEG)
tubes and PEG extensions into the jejunum, in the placement of esophageal dilators,
or in the positioning of a pH or impedance meter [2]. As such, a UTCE might be of more value in daily endoscopic practice than until
recently assumed. In various studies to date, investigators have examined UTCE use
in specific settings, such as Barrett esophagus surveillance, diagnosis of early gastric
cancer or examination of varices in patients with cirrhosis, or gastrointestinal strictures
[3]
[4]
[5]
[6]. However, there are only limited data about actual clinical use of the UTCE in daily
practice [7]
[8].
In the current study, we evaluated actual clinical use of UTCEs in a large patient
cohort with 2 main objectives: (1) evaluate patient comfort and safety and (2) determine
benefits and potential advantages.
Patients and methods
Two researchers (L. H. O. and J. C. G.) retrospectively reviewed the reports of all
patients in the VU University Medical Center (Amsterdam, the Netherlands) endoscopic
database in whom endoscopy was performed with a Fujinon (Tokyo, Japan) EG-530N (diameter,
5.9 mm; working channel, 2.0 mm) or Olympus (Tokyo, Japan) GIF N-180 (diameter, 4.9
mm; working channel, 2.0 mm) endoscope between May 2008 and May 2014. In general at
the VU University Medical Center, regular gastroscopes are used for upper gastrointestinal
tract studies and regular colonoscopes are used for lower gastrointestinal tract procedures.
Only when the endoscopist expects difficulty with the regular endoscope is a UTCE
used.
Patients younger than 18 years of age were excluded from study. We recorded patients’
sex and date of birth, procedure date and indications, underlying disease, use of
conscious sedation or fluoroscopy, complications (during or immediately after the
procedure), and potential advantages of the use of a UTCE over conventional endoscopes.
In our definition, potential advantages included the following: passage of stenosis;
direct nasogastric feeding tube placement; placement or changing of jejunum extension
through existing PEG fistula; nasogastric inspection for improved patient comfort
and safety; stent placement under direct sight; retrograde introduction of the esophagus
through PEG fistula; nasogastric introduction with ear, nose, and throat tumor; confirmation
of bronchoesophageal fistula by direct cannulation; placement of feeding tube through
PEG; and measurement of tumor length before stent placement.
Patient comfort was determined if it was mentioned in the endoscopic report when the
UTCE was specifically used for improved comfort and safety. We considered a safe endoscopy
with the use of a UTCE as the absence of a complication.
In addition, we recorded whether the procedure was performed successfully, which was
defined as completion of the required procedure (eg, placement of feeding tube was
required and placed during the procedure). Failure was defined as not completing the
required procedure (eg, placement of a PEG tube was not possible, regardless of the
cause).
Statistical analyses
Data analysis was performed by using SPSS version 19.0 (IBM SPSS Inc, Chicago, Illinois,
United States). Study parameters were evaluated for normal distribution. Parametric
variables are given as mean (standard deviation [SD]). Continuous, nonparametric variables
are given as median (interquartile range). Differences between variables were tested
with the chi-square test. Statistical significance was set at P < 0.05.
Results
In the study period, 1028 procedures were performed with a UTCE in 457 patients. One
patient had 51 procedures; 9 patients, ≥ 10; 29 patients, ≥ 5; 141 patients, between
4 and 2; and 277 patients, 1 procedure. The patient who had 51 procedures was a male
born in 1942 who was diagnosed with a T4N0 supraglotic larynx cancer in 2005. The
complicated treatment of his cancer resulted in a high-grade esophagus stenosis, which
required 51 Savary dilations during the study period. In 2011, this patient developed
liver metastases, for which he denied treatment. In 2012, he died due to pneumonia.
The number of procedures with a UTCE remained stable over the years: 166, 181, 152,
189, and 165 procedures in 2009, 2010, 2011, 2012, and 2013, respectively (data shown
for complete years).
As can be seen in [Table 1], most of the endoscopic procedures were performed in males (60 %). At the time of
the procedure, mean (SD) age of patients was 64 (20) years. For most procedures (77 %),
the route of introduction was oral. Nasal introduction was most common for feeding
tube placement (117 of 214 procedures) (data not shown). The Fujinon EG-530N gastroscope
was used in 70 % (n = 720) of procedures, and the Olympus GIF N-180 gastroscope was
used in the remaining 30 % (n = 308) (data not shown).
Table 1
Patient characteristics and procedure variables for 457 patients undergoing 1028 procedures
with ultra-thin caliber endoscopes.
|
Age, mean (SD), y
|
64 (20)
|
|
Sex, male, no. (%)
|
621 (60)
|
|
Use of conscious sedation, no. (%)
|
848 (82)
|
|
Use of fluoroscopy, no. (%)
|
151 (15)
|
|
Route of introduction, no. (%)
|
|
|
Oral
|
794 (77)
|
|
Nasal
|
151 (15)
|
|
Through existing PEG fistula
|
48 ( 5)
|
|
Rectal
|
35 ( 3)
|
|
Procedure successful, no. (%)
|
939 (91)
|
SD, standard deviation; PEG, percutaneous endoscopic gastrostomy.
Parametric variables were given as mean (SD). Normal distribution was tested with
the Kolmogorov-Smirnov test.
[Table 2] shows the range of underlying diseases of patients undergoing a procedure with a
UTCE. Most underlying diseases were related to esophagus disease (61 %). About one-third
of the diseases could not be classified to only 1 specific part of the gastrointestinal
tract or were not due to gastrointestinal disease.
Table 2
Underlying diseases, by gastrointestinal tract location, of 457 patients undergoing
1028 procedures with ultra-thin caliber endoscopes.
|
Esophagus, no. (%)
|
626 (61)
|
|
Benign esophagus stenosis after (total) laryngectomy
|
241
|
|
Benign stenosis after esophagus resection
|
177
|
|
Esophageal cancer
|
131
|
|
Benign peptic esophagus stenosis
|
25
|
|
Malignant stenosis after esophagus resection
|
13
|
|
Zenker diverticula
|
10
|
|
Esophageal damage due to caustic damage
|
8
|
|
Stenosis due to antireflux surgery
|
6
|
|
Esophageal stenosis due to graft-vs-host disease
|
5
|
|
Tracheoesophageal fistula
|
5
|
|
Schatzki ring
|
3
|
|
Barrett
|
1
|
|
After surgery for esophagus atresia
|
1
|
|
Stomach, no. (%)
|
32 ( 3)
|
|
Stomach cancer
|
21
|
|
Upper gastrointestinal bleeding
|
9
|
|
After gastric banding
|
2
|
|
Small bowel, no. (%)
|
20 ( 2)
|
|
Inflammatory bowel disease
|
10
|
|
Duodenal cancer
|
8
|
|
Short bowel syndrome
|
2
|
|
Colon, no. (%)
|
42 ( 4)
|
|
After (partial) colon resection
|
30
|
|
Rectal cancer
|
7
|
|
Stenosis of colon neovagina
|
2
|
|
Stenosis of colon due to endometriosis
|
2
|
|
Traumatic rectum stenosis
|
1
|
|
Hepatobiliary, no. (%)
|
15 ( 1)
|
|
Pancreas cancer
|
10
|
|
Cholangiocarcinoma
|
3
|
|
Related to gallstones
|
2
|
|
Other, no. (%)
|
293 (29)
|
|
Related to feeding
|
93
|
|
Ear, nose, throat cancer
|
68
|
|
No gastrointestinal disease
|
45
|
|
Post-radiation stenosis
|
37
|
|
Motility disease
|
18
|
|
Cancer of mediastinum
|
10
|
|
Lung cancer
|
8
|
|
Leukoplakia
|
7
|
|
Anemia
|
6
|
|
Morbus Wegener
|
1
|
If patients underwent more than 1 procedure with an ultra-thin caliber endoscope,
each separate procedure was scored.
[Table 3] shows the indications for the 1028 procedures with UTCEs. Regarding our first objective
in the study, patient comfort and safety, we found it remarkable that in only a minority
(1.4 %) of patients was UTCE used specifically for improved patient comfort. It was
also remarkable that most (82 %) of the patients received conscious sedation (with
midazolam). The remaining patients (18 %) did not receive any form of sedation.
Table 3
Indications for 1028 procedures with ultra-thin caliber endoscopes, categorized according
to route of introduction (oral, nasal, or other [anal, PEG, or colostoma]) and whether
conscious sedation was used.
|
Total, no. (%)
|
Oral
|
Nasal
|
Other
|
|
|
No sedation
|
Conscious sedation
|
No sedation
|
Conscious sedation
|
Sedation N/A
|
|
Nontherapeutic
|
|
|
|
|
|
|
|
Diagnostic
|
75 (7.3)
|
21
|
34
|
2
|
15[
NS
]
|
3
|
|
Inspection of upper gastrointestinal stenosis
|
30 (2.9)
|
9
|
21
|
0
|
0[
NS
]
|
0
|
|
Inspection of stenosis in colon
|
16 (1.6)
|
0
|
0
|
0
|
0[
NS
]
|
16
|
|
Improved patient comfort
|
14 (1.4)
|
10
|
3
|
1
|
0[
NS
]
|
0
|
|
Patient complaints of esophageal passage
|
12 (1.2)
|
10
|
2
|
0
|
0
|
0
|
|
Inspection of PEG tube
|
10 (1.0)
|
5
|
1
|
2
|
1[
NS
]
|
1
|
|
Inspection of bronchoesophageal fistula
|
5 (0.5)
|
0
|
5
|
0
|
0[
NS
]
|
0
|
|
Inspection of common bile duct
|
2 (0.2)
|
0
|
2
|
0
|
0[
NS
]
|
0
|
|
Inspection of colostoma with stenosis
|
2 (0.2)
|
0
|
0
|
0
|
0[
NS
]
|
2
|
|
Therapeutic
|
|
|
|
|
|
|
|
Savary dilation
|
484 (47.1)
|
3
|
463
|
1
|
11[*]
|
6
|
|
Feeding tube placement
|
214 (20.8)
|
27
|
66
|
23
|
94[
NS
]
|
4
|
|
PEG
|
114 (11.1)
|
|
|
|
|
|
|
Push-PEG tube placement
|
52
|
5
|
47
|
0
|
0
|
0
|
|
Change of jejunum PEG tube
|
34
|
0
|
2
|
0
|
0
|
32
|
|
Jejunum PEG tube placement
|
22
|
3
|
5
|
0
|
0
|
14
|
|
Placement of feeding tube through PEG fistula
|
4
|
0
|
0
|
0
|
0
|
4
|
|
Buried bumper syndrome
|
1
|
0
|
1
|
0
|
0
|
0
|
|
Pull-PEG tube placement
|
1
|
0
|
1
|
0
|
0
|
0
|
|
Stent placement
|
34 (3.3)
|
2
|
31
|
0
|
1
|
0
|
|
APC treatment of malignant stenosis
|
1 (0.1)
|
0
|
0
|
0
|
0[
NS
]
|
1
|
|
Unclassified
|
15 (1.5)
|
6
|
9
|
0
|
0[
NS
]
|
0
|
PEG, percutaneous endoscopic gastrostomy; N/A, nonapplicable; APC, argon plasma coagulation.
Difference in sedation between oral and nasal introduction was tested with the chi-square
test.
NS
No significant difference.
* Significant difference (P < 0.05).
Regarding patient safety, we registered few intraprocedural or direct postprocedural
complications. During 6 procedures (0.6 % of all procedures), 6 patients experienced
respiratory problems. Three patients experienced a desaturation, and 2 of these required
administration of flumazenil. The other 3 patients had more severe respiratory problems.
The first patient, with a dens fracture, required placement of a feeding tube. After
an uneventful transnasal introduction and tube placement, the patient developed a
stridor and experienced an acute desaturation to 70 % while sedated with 2 mg of midazolam.
He remained responsive during the episode of respiratory insufficiency and recovered
quickly. However, he was admitted to the medium care unit, remained there for less
than 12 hours, and was discharged without pulmonary complaints. The second patient
had an obstruction of the trachea due to preexisting bleeding. The third patient suffered
from a severe respiratory complication, which was interpreted as a laryngeal spasm
requiring manual ventilation for 3 minutes. One patient was noted to suffer from dental
damage.
A continued review of [Table 3] shows that most (82 %) of the procedures were indicated for therapeutic reasons,
with almost half being for Savary dilation; 21 %, for feeding tube placement; and
11 %, related to PEG tube change or placements. We found that conscious sedation was
used less often in 3 particular procedures. Two of those procedures were carried out
for nontherapeutic reasons: improved patient comfort (11 of 14 procedures) and inspection
of PEG tube (7 of 10 procedures). One of those procedures was conducted for a therapeutic
reason: change of jejunum extension of PEG tube (32 of 34 procedures). Nasal introduction
was used primarily for therapeutic feeding tube placement (117 of 151 nasal introductions),
but this route was not chosen often for other indications.
Findings displayed in [Table 3] also provide information pertinent to our second objective in the study, benefits
and potential advantages of UTCE. Some of the findings reported earlier in this article
regarding our first objective, patient comfort and safety, tie in to our second objective.
That is, use of the UTCE was beneficial primarily for (1) therapeutic or (2) nontherapeutic
diagnostic reasons. A benefit gleaned from our analysis was related specifically to
Savary dilation and inspection of the esophagus. Of the dilations reviewed, 45 % (220
of 484) of procedures were performed after oncologic ear, nose, and throat surgery.
As we reported earlier in the article, the UTCE is also importantly beneficial in
placement of feeding tubes and in PEG-related indications. A summary of new indications
for UTCE, obtained from our review, is given in [Table 4].
Table 4
Innovative uses of ultra-thin caliber endoscopes, determined from review of 1028 procedures.
|
PEG-J (jejunal extension) placement: endoscope introduction through existing PEG tract
|
|
Retrograde esophageal introduction through existing PEG tract
|
|
Inspection of colonic neovagina stenosis
|
|
Direct inspection of common bile duct
|
PEG, percutaneous endoscopic gastrostomy.
In more than half of the procedures, the UTCE had a specific advantage over conventional
gastroscopes ([Table 5]). The main advantage was its small diameter, which made it possible to inspect strictures
or stenoses, as well as to place feeding tubes or stents through stenosis with a small
diameter. Other advantages included introduction of the stomach through an existing
PEG fistula with increased patient comfort and safety. Further details regarding the
advantages of the UTCE over regular endoscopes are shown in [Table 5].
Table 5
Advantages of ultra-thin caliber endoscopes over regular endoscopes.
|
No. (%)
|
|
Unspecified
|
417 (40)
|
|
Passage of stenosis
|
379 (37)
|
|
Direct nasogastric feeding tube placement
|
129 (13)
|
|
Placement or changing of jejunum extension through existing PEG fistula
|
51 ( 5)
|
|
Nasogastric inspection for improved comfort and safety
|
23 ( 2.2)
|
|
Stent placement under direct sight
|
16 ( 1.6)
|
|
Retrograde introduction of the esophagus through PEG fistula
|
6 ( 0.6)
|
|
PEG tube placement made possible, making surgical jejunostomy unnecessary
|
3 ( 0.3)
|
|
Confirmation of bronchoesophageal fistula by direct cannulation
|
2 ( 0.2)
|
|
Placement of feeding tube through PEG
|
2 ( 0.2)
|
PEG, percutaneous endoscopic gastrostomy.
Discussion
Procedures with the use of a UTCE form only a small part of everyday endoscopic practice.
Nonetheless, these versatile endoscopes have several unique characteristics, warranting
a much wider use.
In the current study, we described 1028 procedures performed in adult patients over
6 years. We focused on 2 objectives with the use of a UTCE: (1) patient comfort and
safety and (2) benefits and potential advantages. For our first objective, findings
indicated that the UTCE was safe, with very few complications noted. However, we found
that the UTCE was not often used specifically for improved patient comfort. For our
second objective, we found that the most important advantage of the UTCE in our hands
was inspection and treatment of stenosis in the gastrointestinal tract.
The UTCE was first described in the late 1970 s and early 1980 s [9]
[10]. However, the first comparison of the UTCE with a conventional gastroscope occurred
20 years later [11]. To date, there are only a few studies in which the daily and clinical uses of UTCE
are described [7]
[8]. In a study from Canada, the UTCE was used for routine diagnostic upper endoscopy
in 231 patients. In general, the UTCE was better tolerated than the conventional gastroscope
[8]. In India, 50 procedures with the use of the UTCE were recorded between 2004 and
2007. Of these procedures, 25 were performed for endoscopy-assisted nasogastric tube
placement. The other 25 were related to strictures, trismus, and neurologic damage
[7].
The small caliber of the UTCE is its main advantage, because it allows for passage,
inspection, and treatment of stenosis in the gastrointestinal tract. Mulcahy and Fairclough
[5] described 15 patients, 12 of whom had an esophageal stenosis and 3 of whom had a
stenosis in the colon related to Crohn disease. The study of Aydinli and colleagues
[6] showed similar results, in that there were more upper than lower intestinal stenoses,
with a larger group of patients. In some countries (Japan and France), the UTCE is
also used specifically for diagnostic purposes [12]. In our center, as well as from our experience with our Dutch colleagues in the
Netherlands, a UTCE is not often used for improved patient safety. We are uncertain
as to why the UTCE is not used more frequently. Perhaps costs, frailty of the endoscope,
or unfamiliarity of endoscopists with the advantages of the UTCE limit the more common
use of this versatile scope. The exact place of the UTCE for therapeutic use remains
to be clarified.
Several procedural applications and characteristics of the UTCE are also noteworthy.
The UTCE permits visualization and inspection of the common bile duct. This procedure
was first described 20 years ago in a pregnant patient [13], and, to date, there are 2 studies in which direct inspection of the common bile
duct has been described [14]
[15]. Another important field of use for the UTCE is PEG tube placement and care, including
the direct placement of jejunum extensions. A potential advantage of UTCE is that
it can be safer to use than regular endoscopes in elderly patients and patients with
comorbidities [11]. In our series, 82 % of patients received conscious sedation. It should be noted
that when a patient is undergoing dilation, the actual dilation, rather than the endoscopic
procedure, requires sedation.
In our series, there were few complications, occurring in only 0.6 % of procedures.
The 6 complications were respiratory problems after a UTCE procedure. Although we
did not register major complications, perforation with a UTCE has been described [16]. A downside of the UTCE is its small working channel, rendering smaller biopsy specimens
than obtained with the conventional gastroscope. However, diagnostic performance of
the UTCE remains similar to that found for the conventional gastroscope [17]. Image quality is inferior to that obtained with the conventional gastroscope. However,
we believe this to be of little consequence in daily practice. In fact, comparison
of use of the UTCE versus a conventional endoscope in Barrett esophagus surveillance,
in which visual quality is particularly important, yielded similar results [2].
A limitation of this study was the retrospective analysis of our prospective database.
The advantages of the UTCE were scored retrospectively, possibly biasing the results.
Our percentage for the category of unspecified advantage of the UTCE over a regular
endoscope is high (41 %). However, in case of doubt of whether a specific advantage
existed, we scored the data as unspecified. This percentage is therefore conservative
and likely an overestimation. We did, however, include more than 1000 procedures carried
out over a long period (6 years). Furthermore, we had only 2 investigators score the
procedures, decreasing the interobserver bias.
In conclusion, UTCE can benefit a broad range of patients, potentially reducing the
need for surgical or fluoroscopic treatment. Use of the UTCE makes it possible to
inspect and treat high-grade strictures, place feeding tubes beyond these strictures,
and increase patient comfort during endoscopy. We believe that the UTCE should be
available in every endoscopic unit, and that endoscopists should be aware of the specific
advantages of the UTCE and able to use the UTCE accordingly.
