Introduction
Endoscopic submucosal dissection (ESD) has revolutionized management of gastrointestinal
polyps. Lesions that previously would have had to be removed, either by piecemeal
endoscopic resection or by surgical means, could now be removed en bloc via meticulous
endoscopic guided dissection [1]. In essence, ESD allowed for procurement of a surgical type specimen in a less invasive
manner. The success and widespread adoption of this procedure was predicated on efficient
and purposeful dissection of gastrointestinal tissue using established electrosurgical
units (ESU) [2] and newly developed electrocautery knives [3].
However, existing ESUs used for ESD were initially developed for other purposes such
as sphincterotomy and snare mucosal resection, where changes in tissue composition
are not always accounted for. In ESD, constant changes in tissue composition (submucosa,
fibrosis, etc) and patient related factors necessitate changes in electrocautery setting
to allow for desired effects. Location within the gastrointestinal tract in addition
to the presence of fibrosis also need to be accounted for by the ESU unit. There are
even suggestions that certain electrocautery settings, may be implicated in short
term complications, such as post ESD esophageal stricture [4]. Specifically, rate of stricture formation and degree of fibrosis vary significantly
depending on the type of cut and coagulation current used, with the least degree of
fibrosis occurring associated with EndoCut mode [4]. Most importantly, there is still no consensus for optimal electrocautery settings
for ESD using current ESU systems. Thus, newer ESUs specifically dedicated toward
precise dissection of various gastrointestinal tissue are needed.
A novel ESU, Beamer CE600 Electrosurgical Platform, was designed specifically to address
variability in tissue composition during ESD. The Beamer features automatic cutting
effect (ACE) which provides continuous spark monitoring around an active electrode.
This electrode adjusts voltage, spark and power to deliver consistent, repeatable
cutting and hemostatic effects. It also hosts five endo-modes, which are pulsed currents
that deliver controlled cutting with varying, adjustable degrees of coagulation. With
ninety-nine program memory slots, the Beamer ESU has the ability to save, store and
recall unique settings for esophageal, gastric, colorectal ESD as well as peroral
endoscopic myotomy (POEM) and gastric peroral endoscopic myotomy (G-POEM). However,
its feasibility, effectiveness, and optimal settings have yet to be tested in routine
clinical practice.
The main purpose of our study was to evaluate the feasibility of the Beamer CE600
Electrosurgical Platform during endoscopic dissection of various gastrointestinal
tissue using the suggested settings generated from this study. In doing so, we hope
to characterize the most effective third space endoscopy electrocautery settings using
this novel ESU.
Methods
Determination of ESU settings
Before implementation into human subjects, two in vivo animal labs were utilized to
determine the best current setting for ESD/POEM in the esophagus, stomach and colon.
These settings were then adopted for human use. Institutional review board approval
for animal labs was obtained from Baylor College of Medicine. Parameters included
were ease of dissection, eschar score post resection, muscle injury and or perforation
and bleeding control. Proposed settings were chosen and tested by principal investigator
Mohamed O. Othman in one in vivo animal lab. Optimal settings were determined based
on an assessment of tissue effects with multiple dissecting knives using the Beamer
ESU. The proposed settings were retested in another in vivo animal lab to ensure the
reproducibility of these settings.
ConMed Beamer ESU
The ConMed Beamer ESU “ESD” setting was specifically designed to implement ACE technology
to allow for dissection/hemostasis of varying consistency and resistance. It consists
of a blended pulse current with a short cutting phase followed by a coagulation phase.
In this current setting, the pulse rate is higher than in other settings, and together
with ACE integration and variations in grade setting, a more uniform cutting result
can be seen. The G nomenclature is the equivalent to cutting current (EndoCut I nomenclature
on the ERBE ESU) (ERBE USA, Marietta, Georgia, United States) and corresponds to the
yellow pedal. The blue pedal corresponds to the coagulation mode with the following
nomenclature: Gentle coagulation (equivalent to soft coagulation in the ERBE ESU),
Hot biopsy (equivalent to forced coagulation in the ERBE ESU) and spray coagulation.
[Fig. 1] depicts expected power effect based on a combination of increased G settings and
coagulation degree settings.
Fig. 1 Expected power output in watts generated with increasing G (cutting current) settings.
Expected power output in watts generated when tissue resistance is factored in.
Study design
This is a single-center prospective feasibility study of 59 consecutive patients undergoing
ESD POEM/G-POEM at a tertiary referral center between May 2021 to February 2022. Given
previously reported ESD-related perforation rates of 3% to 13%, it was determined
that a sample size of 50 endoscopic resections would be sufficient to detect any abnormal
increase in the rate of immediate or delayed perforation using this ESU [5]
[6]. The study was approved by Baylor College of Medicine IRB (H-49160 IRB Pr. No.:
20204663).
Patient recruitment
Inclusion criteria were patients scheduled to undergo ESD of gastrointestinal polyps
or undergo esophageal/gastric POEM at Baylor St. Luke’s Medical Center, Houston, Texas,
United States. ESD of gastrointestinal polyps at our institution is performed if the
following criteria are met: endoscopist feels en bloc resection is only feasible via
ESD or hybrid ESD regardless of polyp size, previously manipulated polyps, or lesions
with suggestions of aggressive morphological features. Exclusion criteria were any
patients who were under the age of 18. If inclusion criteria were met, patients were
approached by trained research staff and informed consent was obtained in a preprocedural
clinic visit or in the preoperative area. Patients with multiple polyps were evaluated
independently of each other and were assigned separate IDs. Patients were recruited
consecutively over a period of 12 months. Detailed description of this novel ESU was
provided to potential participants during the consent process. Before consent was
obtained, it was explained to all potential subjects that we were attempting to evaluate
the efficacy of this new ESU to determine its feasibility in routine practice. A trained
research coordinator was present for the entire procedure and collected all procedural
information relevant to the study. Patients were interviewed in recovery area 30 minutes
after the procedure for any immediate post-procedure adverse event (AE). Patients
were contacted 24 hours and 30 days post-procedure to assess for delayed post-procedure
AEs.
Procedure techniques
All procedures were performed by two expert submucosal endoscopists (M.O and S.J)
using a single-channel video endoscope with water jet function Pentax EC38-i10L (Pentax
America, Montvale, New Jersey, United States). At the time of patient recruitment,
endoscopist M.O. had 5 years of ESD experience and over 500 ESD/POEM procedures performed.
Endoscopist S.J. had 1 year of experience and approximately 75 ESD/POEM procedures
performed. For all procedures, a tapered distal cap was attached to the end of the
endoscope. All procedures were performed using either the Dual J -knife (Olympus America,
Center Valley, Pennsylvania, United States) or ProKnife (ORISE ProKnife; Boston Scientific,
Tokyo, Japan). All POEM procedures were performed using the ORISE ProKnife 3.0 mm.
Coagulation graspers (Olympus America, Center Valley, Pennsylvania, United States)
were used to control intraprocedural bleeding.
Outcomes
The primary outcome was technical success, which was defined as the ability to perform
the entire intended procedure (ESD or POEM) using the Beamer CE600 ESU ([Video 1] and [Fig. 2]). For polyps, technical success was defined as en bloc removal of the polyp via
ESD settings using the Beamer CE600 ESU. This included lesions that underwent complete
ESD or hybrid ESD. Hybrid ESD was defined as complete circumferential mucosal incision
followed by completing enough submucosal dissection to deploy a snare around the entire
lesion. If the polyp was removed en bloc but fragmented upon removal, this was considered
technical success but not R0 resection. If the polyp was removed piecemeal, this was
considered technical failure. Secondary outcomes were dissection speed, rate of en
bloc and R0 resection, rate of AEs, and detailed outcomes of the ESU settings. En
bloc resection was defined by visible endoscopic removal of the entire polyp in one
piece. R0 resection and curative resection were determined using European Society
of Gastrointestinal Endoscopy and expanded Japanese criteria [5]
[6]
[7].
ESD of a large rectal polyp using the ConMed Beamer ESU. Traction was provided with
the assistance of a novel retraction toolVideo 1
Fig. 2 ESD resection bed using the ConMed Beamer ESU.
AEs were defined by American Society of Gastrointestinal Endoscopy lexicon [8]. These included intra-procedure muscularis propria (MP) damage (excluding visible
perforation), macro-perforation (defined as a visible MP defect during endoscopy and
micro- perforation (defined as free air seen on imaging with no visible MP defect
on endoscopy) [9], post-electrocautery coagulation syndrome, delayed bleeding (that required endoscopy
or surgery up to 14 days post ESD), abdominal pain 1 day after procedure (defined
as pain rated greater than 4 of 10 on visual pain analog scale), and abdominal pain
30 days post ESD.
Dissection speed for polyps was calculated by first measuring the area of the polyp
(length multiplied by width based on histological measurements). This area was then
divided by dissection time to get dissection speed in cm2/hr. Dissection time was defined as time from first mucosal incision to final removal
of the polyp. For the POEM procedure, distance was calculated in a linear fashion
and consisted of the distance of submucosal tunneling + distance of myotomy.
Statistical analysis
The significance of differences in patient characteristics and clinicopathological
features was determined using chi-square test, Fisher exact test. Factors associated
with R0 resection, dissection changes, and dissection speed were analyzed using logistic
regression analysis. P < 0.05 was considered statistically significant.
Results
Study characteristics
Patients
Fifty-nine consecutive subjects were enrolled over a period of 12 months (15 = POEM/G-
POEM and 44 = ESD) ([Table 1]). For esophageal POEM, indications were type 1 achalasia (n = 3), type 2 achalasia
(n = 5), type 3 achalasia (n = 2), EGJOO (n = 1). G-POEM was performed for idiopathic
gastroparesis (n = 3) and diabetic gastroparesis (n = 1). Among the 44 ESD subjects,
in
total 50 polyps were planned to be removed via ESD.
Table 1 Polyp characteristics, including lesion location, fibrosis, and final pathology.
|
Male, n (%)
|
22 (50)
|
|
HGD, high-grade dysplasia; GIST, gastrointestinal; stromal tumor; NET, neuroendocrine
tumor.
|
|
Age, mean (years)
|
65.6 ± 23.2
|
|
Anticoagulant/antiplatelet use, n (%)
|
11 (25)
|
|
ASA ≥ 3, n (%)
|
33 (75)
|
|
Location, n (%)
|
|
|
10 (20.0)
|
|
|
10 (20.0)
|
|
|
7 (14.0)
|
|
|
23 (46.0)
|
|
|
3 (6.0)
|
|
|
3 (6.0)
|
|
|
28 (56.0)
|
|
|
11 (22.0)
|
|
Pathology, n (%)
|
|
|
10 (20.0)
|
|
|
4 (8.0)
|
|
|
3(6.0)
|
|
|
4 (8.0)
|
|
|
2 (4)
|
|
|
5 (10)
|
|
|
1 (2.0)
|
|
|
8 (16.0)
|
|
|
1 (2.0)
|
|
|
5 (10.0)
|
|
|
2 (4.0)
|
|
|
5 (10.0)
|
Lesions
The most common location was the colon (46%), esophagus (20%), stomach (20%), and
then
duodenum (14%). The mean diameter of the lesions was 3.07 cm2 ± 1.43. The
average surface area size of all lesions was 9.1 cm2 ([Table 1]).
ESU settings used during ESD
Initial incision
The most common initial incision setting for all locations was G5 with only two polyps
incised using the G2 setting. The incision setting for these two polyps were ultimately
changed to G5 to complete the incision successfully ([Table 2]).
Table 2 Referenced optimal electrocautery settings based on location and procedure type for
ConMed Beamer and the equivalent nomenclature for ERBE.
|
CONMED Beamer ESU
|
ERBE ESU equivalent setting
|
|
ESD, endoscopic submucosal dissection; POEM, peroral endoscopic myotomy.
|
|
POEM
|
|
|
Incision and myotomy: Endocut I Mode
|
|
|
Submucosal tunneling: 37W spray Coagulation
|
|
|
Coagulation grasper (hemostasis): 50W soft coagulation
|
|
ESD esophageal
|
|
|
Incision: EndoCut I mode
|
|
|
Dissection: 35W forced coagulation
|
|
|
Coagulation grasper (Hemostasis): 50W soft coagulation
|
|
ESD gastric
|
|
|
Incision: EndoCut I mode
|
|
|
Dissection: 35W forced coagulation
|
|
|
Coagulation grasper (hemostasis): 50W soft coagulation
|
|
ESD duodenum
|
|
|
Incision: EndoCut I mode
|
|
|
Dissection: 30W forced coagulation
|
|
|
Coagulation grasper (hemostasis): 50W Soft coagulation
|
|
ESD colon
|
|
|
Incision: EndoCut I mode
|
|
|
Dissection: 30 to 35W forced coagulation
|
|
|
Coagulation grasper (Hemostasis): 50W soft coagulation
|
Initial dissection
The most common initial dissection setting in all locations was hot biopsy setting
35W. Dissection watts were changed most frequently (more often wattage was decreased)
in the duodenum (66.7%) and colon (55%) due to concern that the wattage may have led
to inadvertent MP injury in the thin-walled duodenum and ascending colon.
Coagulation
Of the polyps, 54% (n = 27) required use of coagulation forceps to control bleeding.
The most common setting was gentle coagulation using 50W.
ESU settings used during POEM
All POEM procedures were performed using an anterior approach with full-thickness
myotomy. The most common incision and myotomy setting used was G2 with only one patient
undergoing incision with G5 due to increased bleeding during mucosal incision. Initially,
submucosal tunneling was performed using 35W spray coagulation but after the third
patient, we realized 37W spray coagulation was more effective ([Table 2]).
Procedures
The ProKnife was used for 36 polyps (72%) and the Dual Knife was used in 14 polyps
(28%). Five polyps required the IT Nano knife as a secondary knife to complete dissection.
When knives were switched, it was only to switch to the IT Nano knife to improve cutting
angle. A stabilizing overtube (double balloon endoluminal interventional platform,
n = 10
and rigidizing overtube, n = 4) was used during colon ESD for 14 polyps (58.3%). Among
all
polyps, 14 (28%) required non-gravity-assisted tissue traction (band traction, clip
in line
traction, suture traction, or novel retraction device). Closure of the resection bed
was
performed for 42 cases (84%) on a whole with 100% of colon resection beds closed.
Closure
was accomplished using through the scope clips and/or suturing devices.
Study outcomes
ESD
Overall technical success was achieved in 90.0% (n = 45) with an R0 resection rate
of
77.1% (n = 37) and curative resection rate of 70.8% (n = 34) ([Table 3]). The two polyps that were removed en bloc but became fragmented were not included
in the R0 resection analysis, since we did not know the true outcome of these two
polyps.
The five polyps that were not removed en bloc were converted to piecemeal EMR (3 severe
fibrosis, 1 intraprocedural duodenal micro-perforation, 1 intraprocedural colonic
macro-perforation).
Table 3 ESD-related procedure outcomes including en bloc resection rate, R0 resection rate,
dissection speed, and complications.
|
Total polyps removed, n
|
50
|
|
ESD, endoscopic submucosal dissection; LOS, length of stay.
|
|
ESD, n (%)
|
45 (90.0)
|
|
Hybrid ESD, n (%)
|
5 (10.0)
|
|
En bloc resection, n (%)
|
45 (90.0)
|
|
R0 resection rate, n (%)
|
37 (77.1)
|
|
Curative resection, n (%)
|
34 (70.8)
|
|
Length of lesion, mean (cm) ± SD
|
3.07 ± 1.43
|
|
Size of lesion, mean (cm2) ± SD
|
9.1 ± 8.6
|
|
Total procedure time, mean (min) ± SD
|
86.8 ± 36.9
|
|
Total dissection time, mean (min) ± SD
|
48.6 ± 28.5
|
|
Dissection speed, mean (cm2 /hour) ± SD
|
14.2 ± 1
|
|
Closure of resection bed, n (%)
|
42 (84.0)
|
|
Complications, n (%)
|
6(12.0)
|
|
Immediate perforation managed endoscopically
|
2
|
|
Delayed perforation requiring surgery
|
2
|
|
Bleeding managed endoscopically
|
1
|
|
Post-electrocautery syndrome
|
1
|
|
Hospitalization LOS, n (%)
|
13 (26.0)
|
|
1 day
|
8 (61.5)
|
|
2 days
|
3 (20)
|
|
4 days
|
1 (6.7)
|
|
5 days
|
1 (6.7)
|
Dissection speed was calculated in 35 patients (4 patients with multiple polyps and
5 patients with piecemeal resection were excluded from analysis) with an average dissection
speed of 14.2 cm2/hr ([Table 3]).
All lesions in the esophagus and stomach were removed en bloc (100%) with an R0 resection
rate of 95%. En bloc/R0 resection in the colon and duodenum were 87%/72.7% and 71.4%/33.3%,
respectively ([Table 4]). Dissection speed in the esophagus, stomach, duodenum, and colorectum were 20.3
cm2/hr, 14.5 cm2/hr, 2.9 cm2/hr and 13.5 cm2/hr, respectively.
Table 4 ESD-related procedure outcomes based on location.
|
-
|
Esophagus
|
Gastric
|
Duodenum
|
Colorectum
|
|
ESD, endoscopic submucosal dissection.
|
|
Total polyps removed, n (%)
|
10 (20.0)
|
10 (20.0)
|
7 (14.0)
|
23 (46.0)
|
|
ESD, n (%)
|
10 (100.0)
|
10 (100.0)
|
6 (85.8)
|
19 (82.6)
|
|
Hybrid ESD, n (%)
|
0
|
0
|
1 (14.3)
|
4 (17.4)
|
|
En bloc resection, n (%)
|
10 (100.0)
|
10 (100.0)
|
5 (71.4)
|
20 (87.0)
|
|
R0 resection, n (%)
|
10 (100.0)
|
9 (90.0)
|
2 (33.3)
|
16 (72.7)
|
|
Size of lesion, mean (cm2) ± SD
|
11.8 ± 8.2
|
8.4 ± 4.8
|
2.6 ± 1.4
|
11.4 ± 10.0
|
|
Total dissection time, mean (min) ± SD
|
34.7 ± 26.4
|
35.1 ± 26.1
|
52.5 ± 23.7
|
50.7 ± 26.6
|
|
Dissection speed, mean (cm2 /hour)
|
20.3 ± 15.3
|
14.5 ± 8.4
|
2.9 ± 1.7
|
13.5 ± 9.9
|
POEM
Technical success of performing esophageal and gastric POEM was 100 %. All POEM procedures
were performed using the ProKnife ([Table 5]). All patients were admitted for routine post-procedure admission without any AEs.
Table 5 Outcomes of POEM procedures.
|
E-POEM
|
|
POEM, peroral endoscopic myotomy.
|
|
|
13 ± 1.7
|
|
|
9.8 ± 2.2
|
|
|
50.0±24
|
|
G-POEM
|
|
|
5.25 ± 0.5
|
|
|
2.75 ± 0.5
|
|
|
46.3 ± 18.3
|
|
|
3 (20)
|
|
|
0
|
Secondary analysis: Association of specific clinicopathologic characteristics with
R0 resection
R0 resection was statistically higher in the esophagus (100%) and stomach (90%) in
comparison to colon (72.7%) and duodenum (33.3%), (P = 0.014)
([Table 6]). R0 resection was statistically higher if fibrosis was not present (P = 0.036). In multinomial logistic regression comparing clinical
factors such as fibrosis, dissection changes and lesion location, the only predictor
for R0
resection was absence of fibrosis (0.043).
Table 6 Variables associated with R0 resection.
|
Variable
|
R0 Resection
|
R1 Resection
|
P value
|
|
Location, n (%)
|
–
|
–
|
–
|
|
Esophagus
|
10 (100)
|
0
|
–
|
|
Stomach
|
10 (100)
|
0
|
–
|
|
Duodenum
|
2 (33.3)
|
4 (66.7)
|
-
|
|
Colon
|
16 (72.7)
|
6 (27.2)
|
P = 0.014
|
|
No fibrosis, n (%)
|
32 (84.2)
|
6 (15.8)
|
P = 0.036
|
|
Dissection watts changes, n (%)
|
12 (63.1)
|
7 (36.8)
|
P = 0.85
|
Association of specific clinicopathologic characteristics with dissection watt changes
In the presence of fibrosis, dissection mode change was not varied based on location
(P = 0.131) ([Table 7]). Overall fibrosis (P = 0.076) and lesion location (P = 0.064), controlling for each effect, were not predictors of dissection change in
multinomial logistic regression. Ultimately, dissection watt changes were made per
the discretion of the endoscopists and often occurred in the duodenum or colon, where
there was a concern of inadvertent thermal damage to the MP rather than ineffective
dissection.
Table 7 Variables associated with dissection watt.
|
Variable
|
Dissection settings changed
|
Dissection setting not changed
|
P value
|
|
Location, n (%)
|
–
|
–
|
–
|
|
Esophagus
|
3 (30)
|
7 (70)
|
–
|
|
Stomach
|
1 (10)
|
9 (90)
|
–
|
|
Duodenum
|
4 (66.6)
|
2 (33.3)
|
–
|
|
Colon
|
11 (50)
|
11 (50)
|
P = 0.176
|
|
Fibrosis, n (%)
|
7 (63.6)
|
4(36.3)
|
P = 0.131
|
|
Polyp size, n (%)
|
20 (40)
|
30 (60)
|
P = 0.02
|
|
ORISE Pro Knife, n(%)
|
18 (36)
|
16 (32)
|
P = 0.048
|
|
DualKnife J, n (%)
|
2 (4)
|
14 (28)
|
–
|
Adverse events
All AEs were graded as mild, moderate or severe based on ASGE lexicon (8). The overall
rate of AE in our cohort was 12.0 % (n = 6). Severe AEs were noted in two patients
(4%):
both had delayed perforation (3 days and 4 days after procedure) which required surgical
right hemicolectomy in an outside hospital. One patient was confirmed to have
post-electrocautery syndrome (presence of fevers, elevated white blood cell count
and
abdominal pain). This patient was treated conservatively with antibiotics and discharged
5
days later, and thus was categorized as a moderate AE. Intraprocedure macro-perforations
in
the colon and duodenum were noted in two patients and were managed endoscopically.
The
duodenal perforation was closed with sutures and through the scope clips and was admitted
and observed for 4 days given post-procedure pain (moderate AE). The colon perforation
was
closed via TTS clips and did not require hospitalization (mild AE). One patient had
delayed
bleeding (patient was on anticoagulation 3 days after ESD and was managed endoscopically
via
clips and endoscopic suturing with 1 day of hospitalization (mild AE). There were
no AEs in
the POEM patient population, or patients undergoing esophageal or gastric ESD. Thirteen
additional patients (26%) were admitted post-ESD for monitoring post procedure without
evidence of perforation.
Discussion
Current ASGE guidelines for ESD provide electrocautery settings for two commercially
available ESU only [10]. In the current study, we evaluated the feasibility and efficacy of a novel ESU
settings designed specifically for endoscopic submucosal dissection using another
commercially available ESU which was not used for submucosal endoscopy procedures
previously. Our data illustrated that the use of the ConMed Beamer ESU, with the suggested
electrocautery settings, allowed for safe and efficient submucosal dissection across
all types of submucosal dissection procedures. We hope that our data, will expand
the armamentarium of ESD capable ESUs in the United States.
The primary outcome of successful completion of the intended procedure using the Beamer
CE600 system was met in 90% of patients during ESD and 100% of patients undergoing
POEM. This is clinically acceptable based on previous published data [10]
[11]
[12], suggesting the novel ESU can support submucosal endoscopic procedures. Moreover,
in cases where technical success was not achieved, lack of completion was not necessarily
secondary to the ESU, but rather, due to specific polyp characteristics that are known
to limit en bloc resection, such as fibrosis [13]
[14]
[15].
Certain quality metrics should be investigated when evaluating ESD outcomes using
new devices [16]. These include, but are not limited to, R0 resection, curative resection, and dissection
speed. In our study, R0 resection rates and curative resection rates using the Beamer
CE600 ESU, were on par with current ESD standards. Moreover, our speed of dissection
during ESD of 14.2 cm2/hr was higher than the minimum accepted ESD dissection speed of 9 cm2/hr [17]. Based on meeting these specific quality metrics, our results indicate the novel
ESU with the suggested settings can be used effectively and safely, while ensuring
high quality metrics.
Traditional ESU often requires changes in dissection settings depending on tissue
location and composition [18]. Interestingly, although changes to the dissection settings of the Beamer CE600
ESU needed to be made in some cases with fibrosis, statistical analysis did not suggest
a correlation between fibrosis and need for dissection setting changes. Moreover,
when changes to the dissection settings needed to be undertaken, it was most commonly
in the setting of fear of inadvertent thermal injury in areas with thin walls (ascending
colon and duodenum). Anecdotally, these results are consistent with our clinical experience,
as dissection using this novel ESU, when compared to other ESU, allows for a more
uniform and smooth dissection despite the variability in tissue composition.
During POEM procedures, the ESU also fared well with total dissection/myotomy times
of under 60 minutes with no complications. Generator setting changes were not required
when switching from submucosal tunneling to myotomy, which makes its clinical use
quite relevant. Lastly, dissection during POEM was primarily carried out with the
ProKnife, which has a central injection function, and may have expedited the procedure
as a whole.
Most importantly, the Beamer CE600 ESU demonstrated an acceptable safety profile.
The overall perforation rate of 6.7% was comparable to the published literature [19] with the majority managed via endoscopic treatment. In addition, all of our AEs
occurred within the colon and duodenum, which have established high AE rates [20]. In fact, our perforation rate of 6.7% in these two locations was significantly
lower than previously documented data [20]. Finally, although 13 patients required hospitalization after the procedure for
pain, only one patient had verified post-electrocautery syndrome (1.6%).
Currently, limited validated data are available regarding optimal ESU settings for
ESD [18]. In our study we aimed to test and reproduce optimal generator settings for quick
easy reference, using the Beamer CE600 ESU. This was first determined after extensive
testing in animal models and then brought to clinical practice. We found during ESD,
an incision setting of G5 and dissection setting of 35W hot biopsy setting was a good
starting point for efficient dissection regardless of location (esophagus, stomach
or colon) or tissue consistency. In the duodenum, 30W hot biopsy setting may be more
acceptable given the fragility of the duodenal wall. In POEM, it appeared settings
set to G2 were most appropriate for incision and myotomy, with 37W Spray Coagulation
being an optimal setting for tunneling.
Our study has several limitations, beginning with its descriptive and non-blinded
nature. However, the primary aim of this study was to introduce novel settings using
this commercially available ESU and describe its efficacy. Second, dissection speed
may have been overestimated or under-estimated, given some patients with multiple
polyps were excluded from speed analysis, due to inability to calculate speed for
each individual polyp within that patient. Third, we cannot say at this point that
the Beamer CE600 is superior to other ESU because comparative analysis has not yet
been performed. However, future studies are pending to help validate its true benefit
during ESD and of its current electrocautery settings.
Conclusions
In a day and age in which ESD is becoming increasingly routine in clinical practice,
diversification and evolution of the technology are needed. This is the first study
evaluating the most optimal electrocautery settings during performance of ESD with
the Beamer CE600. Submucosal endoscopic procedures, regardless of type of dissection
knife used, location, or tissue composition, are feasible and safe with this novel
ESU. In our practice, we will implement the Beamer CE600 for routine use during submucosal
endoscopy procedures. However, further prospective randomized trials are needed to
assess its clinical superiority over standard ESU.
