Primary
Content
OBES SURG (2013) 23:1375–1383
DOI 10.1007/s11695-013-0937-8
ORIGINAL CONTRIBUTIONS
Early Experience with the Incisionless Operating Platform™
(IOP) for the Treatment of Obesity
The Primary Obesity Surgery Endolumenal (POSE) Procedure
J. C. Espinós & R. Turró & A. Mata & M. Cruz &
M. da Costa & V. Villa & J. N. Buchwald & J. Turró
Published online: 17 April 2013
# Springer Science+Business Media New York 2013
Abstract
Background We report our initial experience and 6-month
outcomes in a single center using the per-oral Incisionless
Operating Platform™ (IOP) (USGI Medical) to place
transmural plications in the gastric fundus and distal body
using specialized suture anchors (the Primary Obesity Surgery Endolumenal [POSE] procedure).
Methods A prospective observational study was undertaken
with institutional Ethics Board approval in a private hospital
in Barcelona, Spain. Indicated patients were WHO obesity
class I–II, or III, where patients refused a surgical approach.
Results Between February 28, 2011 and March 23, 2012,
the POSE procedure was successfully performed in 45 patients: 75.6 % female; mean age 43.4±9.2 SD (range 21.0–
64.0). At baseline: mean absolute weight (AW, kg), 100.8±
12.9 (75.5–132.5); body mass index (BMI, kg/m2), 36.7±
3.8 (28.1–46.6). A mean 8.2 suture-anchor plications were
placed in the fundus, 3.0 along the distal body wall. Mean
operative time, 69.2±26.6 min (32.0–126.0); patients were
discharged in <24 h. Six-month mean AW was 87.0±10.3
(68.0–111.5); BMI decreased 5.8 to 31.3±3.3 (25.1–38.6)
(p<0.001); EWL was 49.4 %; TBWL, 15.5 %. No mortality
or operative morbidity. Minor postoperative side effects
resolved with treatment by discharge. Patients reported less
hunger and earlier satiety post procedure. Liquid intake
began 12 h post procedure with full solids by 6 weeks.
J. C. Espinós (*) : R. Turró : A. Mata : M. Cruz : M. da Costa :
V. Villa : J. Turró
Unidad de Endoscopia, Centro Médico Teknon, Vilana, 12,
08022 Barcelona, Spain
e-mail: [email protected]
J. N. Buchwald
Division of Scientific Research Writing, Medwrite Medical
Communications, Maiden Rock, WI, USA
Conclusions At 6-month follow-up of a prospective case
series, the POSE procedure appeared to provide safe and
effective weight loss without the scarring, pain, and recovery
issues of open and laparoscopic bariatric surgery. Long-term
follow-up and further study are required.
Keywords Obesity . Primary Obesity Surgery Endolumenal
(POSE) . Incisionless Operating Platform (IOP) . Weight loss
Introduction
Although bariatric surgery is more effective in achieving
durable weight loss than conventional therapy (i.e., diet, exercise, pharmacotherapy) [1–5], there is an urgent need for
less-invasive solutions for the world’s >1.6 billion overweight
adults and >400 million obese patients [6]. Bariatric surgery
carries a low rate of operative mortality (0.1–0.4 %, restrictive
procedures and gastric bypass) [7, 8], yet is not without
perioperative risk, the possibility of long-term complications
(e.g., for bleeding, leak, wound infection, anastomotic stricture, marginal ulcer, bowel obstruction, and device-related
events), and the need for reoperation. In addition, the majority
of patients who qualify by National Institutes of Health (NIH)
guidelines for bariatric surgery are unable to receive it due to
issues involving cost and accessibility, inadequate insurance,
and/or fear of surgery [9, 10].
From within the milieu of natural orifice translumenal
endoscopic surgery (NOTES), a gastroendoscopic approach
that saw its first human trials within the last decade [11], the
minimally invasive Incisionless Operating Platform™
(USGI Medical, San Clemente, CA, USA) was developed;
its clinical use has been previously described [12–15]. The
IOP devices have had Food and Drug Administration (FDA)
510(k) clearance since 2006 and have attained the CE Mark
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(since 2010) for use in approximating GI tissue without
open or laparoscopic incisions and are employed to carry
out procedures such as endolumenal cholecystectomy [16],
closure of gastrotomies [17], repair of gastro-gastric fistulae
[18], transgastric appendectomy [15], and the ROSE procedure (Repair of Surgery, Endolumenal), an approach for
treating weight regain post bariatric surgery (e.g., after gradual gastric pouch and stoma enlargement following Rouxen-Y gastric bypass [19–23]). The IOP is also in early trials
as the platform of access devices that facilitate the novel
Primary Obesity Surgery Endolumenal (POSE) procedure,
an approach that may provide a means of weight reduction
as effective as bariatric surgery, yet with even greater safety.
POSE has been performed successfully by both surgeons
and gastroenterologists in North America, Europe, and the
Middle East; to our knowledge, this study provides the first
formal English-language presentation of outcome data.
In the POSE procedure, stomach tissue is plicated in 8–9
locations in the fundus and in 3–4 in the distal body using
specialized suture anchors. The plicated areas mechanically
and physiologically restrict contact of ingested food with the
full surface area of the stomach. It is hypothesized that the
anchored plications may more rapidly activate gastric stretch
receptors in response to food, partially defunctionalizing the
fundus by limiting its ability to accommodate a meal [24–26].
Additional distal plications are expected to slow antral mill
contractions and delay complete gastric emptying, thereby
reducing hunger and initiating earlier and prolonged satiety
[27, 28]. By these — and perhaps other — mechanisms,
POSE may facilitate durable weight loss and comorbidity
improvement while not precluding other interventions.
Between February 28, 2011 and March 16, 2012 in our
institution, the Centro Médico Teknon (Barcelona, Spain),
we performed the POSE procedure in a series of patients
with an initial mean body mass index (BMI, kg/m2) of 36.7.
We present our experience to date and 6-month outcomes
with the POSE procedure.
OBES SURG (2013) 23:1375–1383
Endpoints, Data Collection
Safety endpoints analyzed were minor and major complications. Operative time and duration of hospital stay were
recorded. The primary effectiveness endpoint was weight
loss at 6 months expressed as mean change from baseline in
absolute weight (AW) and BMI. In addition, percentage
excess weight loss (%EWL), and percentage total body
weight loss (%TBWL) were calculated. Percentage EWL
was calculated using a constant BMI of 25 kg/m2 to determine
ideal body weight (IBW): %EWL=(baseline AW−6-month
AW)/(baseline AW−IBW)×100; %TBWL was calculated as:
%TBWL=(baseline AW−6-month AW)/(baseline AW)×100.
Patients
Patients who considered undergoing the POSE procedure
underwent an informed consent process concluding with their
signing of the Ethics Board-approved consent form. To participate in the study, patients needed to present with a BMI in the
class I or II obesity range (World Health Organization [WHO]
[32]), or in the WHO class III range but be unwilling to undergo
a surgical procedure. As the procedure is new, patients with a
BMI between 30 and 40 were felt to be the best candidates to
provide the probable best outcomes for these lower- to midrange BMI patients while reserving standard bariatric procedures for patients with a BMI >40. Patients were required to be
>20 years of age and able to return to the hospital for all followup visits. Nutritional evaluation and psychological screening
provided confirmation of patients’ ability and willingness to
comply with the post-procedure diet and exercise program.
Patients paid independently for their procedures with no USGI
financial support provided for either the patient or clinician.
Patients were excluded if they were non-ambulatory or
had significant mobility impairment; if they had a known
and untreated hormonal or genetic cause for obesity; or, if
they had work hours, family obligations, or transportation
issues that could interfere with their return for all scheduled
evaluations.
Methods
Endoscopic Equipment
Study
In 2011, our endoscopic group in the Centro Médico Teknon
undertook a clinical study of the POSE procedure. The
study was of a prospective, single-center, non-comparative
observational design. The study protocol and case report
form stipulate good clinical practices (GCPs) as defined in
ISO EN 14155–1 and −2 [29, 30]. All patients were asked to
provide written informed consent prior to surgery in accord
with Teknon Ethics Board requirements and GCP guidelines
outlining patient protections stipulated by the Declaration of
Helsinki [31].
The incisionless, flexible endosurgical TransPort® Endoscopic
Access Device (USGI Medical) provides a stable platform
through which to work in the operative site. The TransPort
has four working ports that deploy an endoscope and three
specialized instruments: the g-Prox EZ® Endoscopic Grasper, a
flexible shaft with a jawed gripper for mobilizing and approximating a tissue fold; the g-Lix™ Tissue Grasper, a flexible
probe with a distal helical tip designed to assist the g-Prox in
capturing target tissue (Fig. 1a); and the g-Cath EZ™ Suture
Anchor Delivery Catheter, a catheter system with a needle at its
distal tip that, after advancement through the lumen of the
OBES SURG (2013) 23:1375–1383
Fig. 1 a Incisionless Operating Platform™ with TransPort® Endoscopic Access Device; b g-Cath EZ™ Suture Anchors; c schematic of
anchors holding plicated tissue permitting serosal approximation.
gProx, penetrates the mobilized target tissue, installs a pair of
pre-loaded Suture Anchors™, and cinches the anchored tissue
fold (Fig. 1b). The mesh suture anchors (pledgets) were
designed to distribute holding forces across the plication contact points in order to reduce the tissue trauma often associated
with sutures, thereby facilitating postoperative healing and
increasing procedure durability.
Surgical Technique
The POSE procedure was conducted in the operating room
using general anesthesia.
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Prior to intubation of the Transport, a standard gastroscopy was routinely performed to aspirate any accumulation
of fluid, as well as to verify that the pathology of the
anatomy was not irregular. The shape of the fundus was
noted, as this may affect the number of suture anchors
placed. The TransPort was inserted transorally and advanced
into the stomach. Visualization was achieved through the
TransPort with a small-diameter endoscope.
Suture-anchor plications were placed in the fundus and
distal body with the intent of reducing fundal accommodation and inducing antral dysmotility following meal consumption. To achieve each plication, target tissue was
grasped with the g-Lix and pulled and guided into the jaws
of the g-Prox. The g-Prox jaws were closed. After insertion
of the g-Cath system through the g-Prox lumen, the g-Cath
needle tip was advanced through the tissue fold and a suture
anchor deployed on each side of the tissue fold to approximate it; the suture anchors were cinched to an appropriate
tension. The proximal end of the suture was cut, leaving the
cinched anchor pair holding the apposed tissue (Fig. 1c).
After the first 15 cases, a technical improvement was by
made by cutting the sutures using the g-Prox instead of an
external scissors; this resulted in shortening the operative
time by 20 min in the ensuing cases. The g-Cath system
facilitated creation of secure plications without the challenge of endoscopic knot tying and the associated potential
tissue trauma.
Generally, 8–9 plications in the fundus proved sufficient
to reduce the surface area significantly. The orientation of
the g-Prox influenced alignment of the tissue fold once the
g-Cath needle was deployed. When the needle passed from
anterior to posterior, the fold was created at a medial to
lateral angle; the second pair of suture anchors was placed
approximately 2–3 cm from the previous pair, creating and
continuing a tissue ridge. This approach appeared to be the
quickest method of setting up subsequent anchor placements
and providing visual confirmation of fundal surface reduction. After placing four suture anchors, the tissue ridge
routinely extended to the lateral limit of the fundus; a second
row, anterior to the first row, was then started and completed
using four suture anchors. More anchors may be necessary
to achieve a complete reduction; however, the two tissue
ridges appeared to confer the greatest fundal surface contraction using the fewest sutures. Following placement of
the fundal tissue anchors, we ensured that the apex of the
fundus was pulled down to the same level as the gastroesophageal junction.
With the aim of disrupting the gastric antral mill, 3–4
additional plications were placed in the distal body, creating
a tissue ridge near the mouth of the antrum opposite the
angular incisure. After creation of a tissue ridge in the distal
body, the instruments and TransPort were removed, and
anesthesia withdrawn. A standard gastroscope was routinely
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used following the procedure to view the plications and
verify that there was no bleeding. The CO2 was aspirated
and the stomach collapsed prior to final extubation.
Postoperative Care
In the first 4 weeks post procedure, patients were placed on a
customized, calorie-restricted diet (per day: 800 calories, minimum 50–70 g protein, maximum 30 g fat, ≥64 oz fluids) that
transitioned from liquid to pureed foods, to soft solids, and
then full solids in the sixth week. In the sixth week, patients
were counseled to maintain their daily diet at 1,200 calories.
Walking exercise (10–15 min 2–3 times/day) was encouraged
in the first 4 postoperative weeks, with instructions to increase
exercise in the fifth week to an investigator-approved aerobic
regimen of 35–45 min 5 times/week.
Because this procedure was new to us, we preferred a
rigorous and cautious follow up schedule: Follow-up visits
were performed at 1, 2, and 3 weeks, and at 1, 2, 3, 4, 5, and
6 months. Upper GI series were not performed as a rule.
Statistical Analysis
OBES SURG (2013) 23:1375–1383
Table 1 Patient baseline characteristics
Characteristic
Value
Mean±SD (rangea)
N=45
Age (years)
Height (m)
AW (kg)
BMI (kg/m2)
IBWb (kg)
EWc (kg)
Gender, N (%)
Male
Female
BMI by WHO class, N (%)
Class Id (30.0–<35)
Class II (≥35.0–<40)
Class III (≥40.0)
43.4±9.2 (21.0–64.0)
1.7±0.1 (1.5–1.8)
100.8±12.9 (75.5–132.5)
36.7±3.8 (28.1–46.6)
68.7±5.8 (59.0–81.0)
32.1±10.7 (8.3–60.3)
11 (24.4)
34 (75.6)
15 (33.3)
24 (53.3)
6 (13.4)
AW absolute weight, BMI body mass index, IBW ideal body weight, EW
excess weight, WHO World Health Organization weight classifications
a
Range=min–max
b
IBW (kg)=height (m)2 ×25 kg/m2
EW (kg)=AW (kg) – IBW (kg). (Determination of EW for this study
was based on an “ideal” body weight [IBW] equivalent to a BMI of
25 kg/m2 – the cut-off point that defines overweight in the current
WHO classification)
c
Statistical analyses were performed using SAS® software v.
1.9 (SAS, Cary, NC). Patient baseline characteristics and
perioperative outcomes were summarized; continuous parameters were reported as number of non-missing observations (N), mean, standard deviation (SD), and range.
Categorical parameters, both at baseline and postoperatively, were reported as count and percentage. Continuous outcome variables were generally reported as mean, SD, and
range. Mean change values at 6 months in AW and BMI
were calculated along with corresponding 95 % confidence
intervals (CIs) for mean differences. Also, 95 % CIs were
calculated for mean %EWL and mean %TBWL at 6 months,
as well as for subgroup %TBWL means at 1, 3, and
6 months. Measures of change from baseline were analyzed
using paired-samples t-tests. Between-group comparisons
(i.e., %TBWL subgroup analyses) were carried out using
analysis of variance (ANOVA) for independent samples.
Scatter diagrams and correlation analysis were used to explore %TBWL and %EWL relationships with baseline BMI.
Statistical significance was set at p<0.05.
d
Two patients had BMI <30 (i.e., 28.1 and 29.9 kg/m2 )
baseline BMI was 36.8. There were 15 patients with class
I obesity (33.3 %), 24 patients with class II obesity (53.3 %),
and six patients with class III obesity (13.4 %).
Operative Outcomes
All POSE cases were performed by experienced endoscopists
with no intraoperative adverse events, no conversions or failed
procedures, and no postoperative re-hospitalizations. The
mean number of total suture anchors placed was 11.3±1.1
(8–14) (Table 2). The mean operative time was 69.2 ±
26.6 min. Following the procedure, 100 % of patients reported
less hunger and earlier satiety. All patients were discharged
between 12 and 24 h.
Weight Outcomes
Results
Baseline Patient Characteristics
As shown in Table 1, the majority of patients were female
(75.6 %). The mean age was 43.4±9.2 years (21–64). Mean
AW was 100.8±12.9 kg (75.5–132.5); height, 1.7±0.1 m
(1.5–1.8); and BMI, 36.7±3.8 (28.1–46.6). The median
Postoperative weight outcomes were available in 80.0 %
(27/34) of protocol-compliant patients at the 6-month time
point. Paired samples t-tests indicated that obesity parameters were significantly reduced (Table 3). Mean AW (kg)
was 87.0 ± 10.3 compared to 103.3 ± 13.1 at baseline, a
within-patient mean change of −16.3±7.1 (95 % CI, −19.1 to
−13.5; p<0.001). Percentage TBWL was 15.5±6.1 (95 % CI,
13.1 to 17.9). BMI was 31.3±3.3 relative to a baseline measure
OBES SURG (2013) 23:1375–1383
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Table 2 Perioperative outcomes
Characteristic
Value
Mean±SD (range)
(N=45)
Procedure duration, min
Number of anchors, fundus
Number of anchors, distal body
Number of additional anchors
Total number of anchors
69.2±26.6 (32.0–126.0)
8.2±1.1 (5.0–10.0)
3.0±0.5 (2.0–5.0)
0.0±0.2 (0.0–1.0)
11.3±1.1 (8.0–14.0)
of 37.2±3.9, a mean change of −5.8±2.5 (95 % CI,
−6.8 to −4.8; p<0.001); %EWL was 49.4±21.5 (95 % CI,
40.9 to 57.9).
Subgroup analyses of weight loss (i.e., %TBWL) by
gender, age, and BMI at 1, 3, and 6 months following POSE
are presented in Table 4. Due to the relatively small number
of class III patients (n=6) in the study, patients were divided
into two BMI groups: class I obesity (30.0 to <35.0) vs.
class II (≥35 to 40) and above. Analyses indicated that there
were no significant differences in weight-loss outcomes
between males and females, age groups (i.e., <40, ≥40 to
<50, ≥50 years), or between BMI groups (i.e., BMI <35.0,
BMI ≥35.0) across time points.
Scatter diagrams and correlation analyses were used to
further examine the relationship between baseline BMI and
the efficacy of the POSE procedure as measured by %TBWL
and %EWL at 6 months. Percentage TBWL and EWL correlated with baseline BMI at r=0.29 (p=0.14), and r=0.23 (p=
0.25), respectively. Although the relationship between baseline BMI and weight outcome was not statistically significant,
several interesting observations were noted—particularly with
regard to patients with BMI<35 vs. those with BMI≥35.
Seventy-five percent (6/8) of BMI<35 patients, and 95 %
(18/19) of BMI≥35 patients experienced greater than 5 %
TBWL at 6 months. Also, 75 % (6/8) of BMI<35 patients,
and 89.5 % (17/19) of BMI≥35 patients experienced greater
than 25 % EWL over the same period. POSE patient 6-month
%TBWL and %EWL correlated at r =0.83 (p <0.001).
Overall, %TBWL and %EWL correlated at a mean r=0.69
(range: 0.61–0.83) across follow-up time points. Generally
speaking, both BMI subgroups trended upward along percentage weight-loss outcome measures.
Complications
There was no mortality in the series and only two minor
adverse events as defined by the American Society for Gastrointestinal Endoscopy (ASGE) [33]. Post POSE, there was one
case of low-grade fever that resolved with oral antibiotic
treatment and another patient who returned to the hospital on
the second postoperative day with chest pain; complications
from the procedure and cardiovascular issues were ruled out
and the patient was sent home. Minor postoperative side effects
included sore throat, stomach pain, nausea, and chest pain
(Table 5). There were three cases of vomiting that resolved
within the first 12 h with no requirement of additional hospital
stay. One patient was discharged on the second postoperative
day for her personal convenience, not due to medical necessity.
There was no device-related morbidity.
Discussion
Current study results demonstrate the clinical safety and
effectiveness of the POSE procedure for primary weight
loss in a small cohort of obese patients. In addition to
achieving significant weight loss with no major complications, POSE required just over an hour of procedural time,
incurred no incisions or scars, and resulted in a fast recovery
time and brief hospital stay.
Table 3 Mean weight loss at 6 months
Parameter
Mean±SD (range)
(N=27)
Mean change±SD
95 % CI
p valuea
AW (kg)
BMI (kg/m2)
EWLc (%)
TBWLe (%)
87.0±10.3 (68.0–111.5)
31.3±3.3 (25.1–38.6)
49.4±21.5 (13.7–98.4)
15.5±6.1 (2.4–24.5)
−16.3±7.1
−5.8±2.5
__
__
−19.1, −13.5b
−6.8, −4.8b
40.9, 57.9d
13.1, 17.9‡
<0.001
<0.001
__
__
AW absolute weight, BMI body mass index, EWL excess weight loss, IBW ideal body weight, TBWL total body weight loss
a
Paired samples t-test assessing change from baseline
b
95 % CI of mean difference
c
95 % CI of the mean
d
EWL (%)=(AW change [kg]/(baseline AW [kg]−IBW [kg]))×100
e
TBWL (%)=(AW change [kg]/baseline AW [kg])×100
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OBES SURG (2013) 23:1375–1383
Table 4 Total body weight loss by month and subgroup
Month
Parameter
N
Mean±SD (range)
(%)
Month 1
TBWL by gender
Females
32 8.1±2.4
Males
11 9.4±1.5
TBWL by age (years)
<40
16 8.4±1.9
≥40 to <50 15 8.2±2.7
≥50
12 8.6±2.2
TBWL by BMI (kg/m2)
<35.0
13 8.3±2.8
≥35.0
30 8.4±2.0
Month 3
TBWL by gender
8
19
p value
(4.4–14.3)
(6.4–11.4)
7.2–8.9
8.4–10.4
0.09
(5.3–11.4)
(4.4–14.3)
(5.1–11.4)
7.4–9.4
6.7–9.7
7.2–10.0
0.93
(4.4–14.3)
(5.3–11.4)
6.6–10.1
7.7–9.2
0.90
10.8–14.3
13.0–17.1
0.12
10.2–15.3
10.8–17.1
11.1–14.8
0.75
9.4–14.5
12.0–15.5
0.22
11.4–17.5
14.6–22.4
0.14
12.0–19.1
8.7–22.0
10.6–20.7
0.99
7.7–19.0
13.6–19.2
0.24
Females
29 12.6±4.6 (4.0–20.3)
Males
10 15.1±2.9 (9.3–19.7)
TBWL by age (years)
<40
15 12.8±4.6 (4.1–20.3)
≥40 to <50 13 14.0±5.2 (4.0–19.9)
≥50
11 12.9±2.7 (7.3–16.1)
TBWL by BMI (kg/m2)
<35.0
12 11.9±4.0 (4.0–17.6)
≥35.0
27 13.8±4.4 (4.1–20.3)
Month 6
TBWL by gender
Females
20 14.5±6.4 (2.4–24.5)
Males
7
18.5±4.2 (11.6–23.2)
TBWL by age (years)
<40
11 15.6±5.3 (7.8–23.7)
≥40 to <50 8
15.3±8.0 (2.4–24.5)
≥50
8
15.6±6.1 (4.5–21.4)
TBWL by BMI (kg/m2)
<35.0
≥35.0
95% CI
a
13.3±6.7 (2.4–21.0)
16.4±5.8 (4.5–24.5)
b
TBWL total body weight loss, BMI body mass index
a
95% CI of the mean
b
Analysis of variance (ANOVA) for independent samples
Table 5 Postoperative
complications
Complication
N (%)
(N=45)
Fever
Sore throat
Stomach pain
Nausea
Vomiting
Chest pain
1 (2.2)
5 (11.1)
15 (33.3)
6 (13.3)
3 (6.7)
2 (4.4)
There was no mortality in the current study, whereas,
≥30-day mortality in all categories of bariatric surgery (from
purely restrictive to malabsorptive-restrictive to purely
malabsorptive procedures [34]) is 0.1 % to 0.28 % according
to meta-analysis [35]. In the POSE cohort, there were no
(0.0 %) major perioperative complications, only minor complications that cleared rapidly, while the overall complication rate
for restrictive and malabsorptive-restrictive bariatric procedures
has been estimated at 1.1 % to 2.7 % [36].
Although current POSE findings at 6-month follow-up
are preliminary and based on a small cohort, POSE appeared
equally effective for both sexes and for all age and BMI
groups studied. In relation to the recent interest in bariatric
treatment for low-BMI patients, both BMI groups (baseline
<35 and ≥35) trended upward along percentage weight-loss
outcome. However, lower-BMI POSE patients appeared to
experience relatively higher %EWL than higher-BMI patients; conversely, low-BMI patients demonstrated slightly
lower %TBWL over time than their higher-BMI counterparts. These seemingly contradictory results are due to the
choice of outcome measure.
Several measures of weight loss have been employed in
the scientific literature, rendering comparison of outcomes
within and across bariatric methodologies challenging. Reports of medical/nonsurgical therapies typically present actual weight loss or %TBWL; whereas, weight-loss results
for primary bariatric surgical procedures are mainly reported
as %EWL. Further, %EWL has been reported in the literature using two different methods [37]. The EWL calculation
reported most frequently utilizes the Metropolitan Life
Tables (MLT) to determine ideal body weight; whereas,
the second method uses a constant BMI of 25. In the current
study, the second measure of EWL was employed, as some
have suggested it is a more accurate representation of ideal
body weight due to the narrow and outdated range of anthropometric measurements upon which the MLT classifications are based [37–39]. Practitioners in the emerging area
of endoscopic bariatric procedures, such as the ASGE and
the American Society for Metabolic and Bariatric Surgery
(ASMBS) Task Force, are discussing the most apt measurement(s) with which to compare weight-loss effectiveness
across endoscopic procedures and in relation to bariatric
and non-interventional approaches [40].
In the current study, the mean 6-month POSE TBWL was
15.5 %, which is significantly better than the minimum 5.0 %
TBWL threshold recommended for achievement of weightrelated comorbidity resolution [39] and congruent with the
approximately 15.0–25.0 % TBWL seen in systematically
reviewed analyses of patients following very low-calorie diet
and exercise programs for <6 months (although fewer than
9.0 % of the diet and exercise regimen patients maintained this
weight loss at 1 year) [41, 42]. Using the MLT calculation of
EWL for POSE at 6 months—40.0 %—POSE results were
OBES SURG (2013) 23:1375–1383
comparable to the 1-year laparoscopic adjustable gastric
banding mean EWL of 42.6 % reported by recent metaanalysis using the MLT standard [43]. At 6-month followup, more than 80.0 % of POSE patients had achieved ≥25 %
EWL, and the overall POSE patient mean EWL as calculated
by either metric (MLT [40.0 %] or BMI 25 as ideal end point
[49.4 %]) far exceeded the minimum 1-year goal of 25.0 %
EWL recommended for endoscopic bariatric therapies by the
ASGE/ASMBS Task Force [40]. Patients in the current POSE
cohort who have reached the 9- and 12-month time points
have continued their weight-loss trend with no complications.
There are several other new endoscopic procedures for
short- and long-term primary weight loss that take different
mechanical approaches, ranging from gastric-volume reduction (e.g., the EndoCinch, Bard, Murray Hill, NJ; and TERIS,
BaroSense, Redwood, CA) to exposure of the jejunum to
partly digested nutrients (EndoBarrier, GI Dynamics, Lexington, MA). In initial studies, these procedures have shown
19.9–46.0 % EWL at 6 months to 1 year [44]. Early trials of
TERIS and Endo Barrier resulted in the following major
Fig. 2 Endoscopic view of fundal and distal body plications immediately post POSE.
1381
Fig. 3 Endoscopic view of suture anchor stability at 6 months following POSE.
complications: gastric perforation, pneumoperitoneum requiring percutaneous intervention [45], device migration, obstruction, bleeding [46, 47]).
The TERIS procedure and the POSE procedure using the
IOP differ in several important respects. The TERIS is an
implant-based procedure, with plastic anchors placed near
the cardia to create an internal restriction similar to a gastric
band. The TERIS devices acquire tissue via suction, which
has been found to provide tissue plications of inconsistent
size and depth. The POSE procedure using the IOP is not
implant-based, and instead uses sutures and pledgets to
secure durable folds in gastric tissue. The IOP acquires
tissue using a grasper with a long, 33-mm jaw that allows
full-thickness bites to be secured under direct visualization.
The POSE procedure itself is not thought to be restrictive in
its mechanism of action, and involves plicating the fundus
and distal gastrum of patients to induce a physiological
response: earlier fullness and prolonged satiety. Further
investigation of these endoscopic devices and procedures
is required.
More study is required to understand the mechanisms of
action involved in POSE weight loss using the method of
multiple individual tissue plications. The safest and most
effective locations for gastric anchor placement in POSE are
still being refined. Also unknown is the minimum number
of suture anchors that would provide maximum weight-loss
effectiveness in the fundus and distal body.
A weight-loss approach such as the POSE procedure
depends for its success upon creating the most favorable
conditions for GI wound healing. GI tissue healing following suturing requires incorporation of the muscular, serosal,
and submucosal layers to trigger an inflammatory response
sufficient to promote early proliferation of collagen at the
plication site [48, 49]. The snowshoe-shaped suture anchors
deployed through the g-Cath appear to be an attractive
1382
option relative to traditional suturing to achieve tissue apposition. When sutures are cinched across gastric tissue folds to
form plications, overtightening may cut through tissues, precipitating wound dehiscence [50]. As demonstrated in a shortterm preclinical study comparing four suture anchor designs
used to make full-thickness gastric plications, the expandable
suture anchors provided what appeared to be a firm, nondamaging amount of compression, pliant in response to the
inflammatory process that facilitated durable tissue remodeling [51]. In the current study, Fig. 2 shows an endoscopic view
of fundal and distal body plications immediately post POSE;
Fig. 3 shows suture-anchor stability at the 6-month postPOSE study end point.
The POSE procedure can be performed by a well-trained
endoscopist or bariatric surgeon. As with bariatric surgical
procedures, POSE should be undertaken within a supportive,
comprehensive, obesity management program, and should be
viewed as a tool for weight loss and stimulus to behavior
modification rather than as an independent solution to obesity.
A weakness of this study was that it was conducted on a
small patient series without a control group. Although data
on comorbidities and quality of life were collected throughout the study, they were not collected uniformly and, thus,
could not be appropriately analyzed and described as part of
the 6-month findings; follow-up reports should include these data. As POSE is thought to have a significant impact on
hunger and satiety, objective evaluations of these parameters
would be of value in future investigations.
To our knowledge, this is the first peer-reviewed publication of POSE weight-loss outcomes in obese patients.
Initial results are encouraging. Marked weight loss with
POSE with only minor perioperative side effects compares
favorably with outcomes of restrictive bariatric surgical procedures while providing a better safety profile over the short
term. POSE may also provide a novel means of early intervention in overweight patients’ progression into obesity and
increasing comorbid illness. Long-term follow-up of this
series and additional rigorous studies of POSE for weight
loss are required to evaluate its safety, effectiveness, and
patient acceptance.
Acknowledgments We thank Dror Rom, PhD, Prosoft Software,
LLC (Wayne, PA), for performing the statistical analysis, and T.W.
McGlennon, M3, LLC (Maiden Rock, WI) for statistical consultation.
We also thank Maribel Sanchez for nutritional consultation during the
study, Marta Lasaosa for administration, Sandra Andres for endoscopic
nursing, Dr. Monica Prat for psychiatric consultation, and Sonia Oliva
for psychological evaluation.
Disclosure The clinical study at the Teknon site was not financially
supported and was conducted independently by Teknon’s physicians.
Manuscript development was supported by USGI Medical, USA. J.N.
Buchwald is the director and chief scientific research writer at
Medwrite LLC, a CRO under contract with USGI. Manuscript development was supported by USGI Medical, Inc.
OBES SURG (2013) 23:1375–1383
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DOI 10.1007/s11695-013-0937-8
ORIGINAL CONTRIBUTIONS
Early Experience with the Incisionless Operating Platform™
(IOP) for the Treatment of Obesity
The Primary Obesity Surgery Endolumenal (POSE) Procedure
J. C. Espinós & R. Turró & A. Mata & M. Cruz &
M. da Costa & V. Villa & J. N. Buchwald & J. Turró
Published online: 17 April 2013
# Springer Science+Business Media New York 2013
Abstract
Background We report our initial experience and 6-month
outcomes in a single center using the per-oral Incisionless
Operating Platform™ (IOP) (USGI Medical) to place
transmural plications in the gastric fundus and distal body
using specialized suture anchors (the Primary Obesity Surgery Endolumenal [POSE] procedure).
Methods A prospective observational study was undertaken
with institutional Ethics Board approval in a private hospital
in Barcelona, Spain. Indicated patients were WHO obesity
class I–II, or III, where patients refused a surgical approach.
Results Between February 28, 2011 and March 23, 2012,
the POSE procedure was successfully performed in 45 patients: 75.6 % female; mean age 43.4±9.2 SD (range 21.0–
64.0). At baseline: mean absolute weight (AW, kg), 100.8±
12.9 (75.5–132.5); body mass index (BMI, kg/m2), 36.7±
3.8 (28.1–46.6). A mean 8.2 suture-anchor plications were
placed in the fundus, 3.0 along the distal body wall. Mean
operative time, 69.2±26.6 min (32.0–126.0); patients were
discharged in <24 h. Six-month mean AW was 87.0±10.3
(68.0–111.5); BMI decreased 5.8 to 31.3±3.3 (25.1–38.6)
(p<0.001); EWL was 49.4 %; TBWL, 15.5 %. No mortality
or operative morbidity. Minor postoperative side effects
resolved with treatment by discharge. Patients reported less
hunger and earlier satiety post procedure. Liquid intake
began 12 h post procedure with full solids by 6 weeks.
J. C. Espinós (*) : R. Turró : A. Mata : M. Cruz : M. da Costa :
V. Villa : J. Turró
Unidad de Endoscopia, Centro Médico Teknon, Vilana, 12,
08022 Barcelona, Spain
e-mail: [email protected]
J. N. Buchwald
Division of Scientific Research Writing, Medwrite Medical
Communications, Maiden Rock, WI, USA
Conclusions At 6-month follow-up of a prospective case
series, the POSE procedure appeared to provide safe and
effective weight loss without the scarring, pain, and recovery
issues of open and laparoscopic bariatric surgery. Long-term
follow-up and further study are required.
Keywords Obesity . Primary Obesity Surgery Endolumenal
(POSE) . Incisionless Operating Platform (IOP) . Weight loss
Introduction
Although bariatric surgery is more effective in achieving
durable weight loss than conventional therapy (i.e., diet, exercise, pharmacotherapy) [1–5], there is an urgent need for
less-invasive solutions for the world’s >1.6 billion overweight
adults and >400 million obese patients [6]. Bariatric surgery
carries a low rate of operative mortality (0.1–0.4 %, restrictive
procedures and gastric bypass) [7, 8], yet is not without
perioperative risk, the possibility of long-term complications
(e.g., for bleeding, leak, wound infection, anastomotic stricture, marginal ulcer, bowel obstruction, and device-related
events), and the need for reoperation. In addition, the majority
of patients who qualify by National Institutes of Health (NIH)
guidelines for bariatric surgery are unable to receive it due to
issues involving cost and accessibility, inadequate insurance,
and/or fear of surgery [9, 10].
From within the milieu of natural orifice translumenal
endoscopic surgery (NOTES), a gastroendoscopic approach
that saw its first human trials within the last decade [11], the
minimally invasive Incisionless Operating Platform™
(USGI Medical, San Clemente, CA, USA) was developed;
its clinical use has been previously described [12–15]. The
IOP devices have had Food and Drug Administration (FDA)
510(k) clearance since 2006 and have attained the CE Mark
1376
(since 2010) for use in approximating GI tissue without
open or laparoscopic incisions and are employed to carry
out procedures such as endolumenal cholecystectomy [16],
closure of gastrotomies [17], repair of gastro-gastric fistulae
[18], transgastric appendectomy [15], and the ROSE procedure (Repair of Surgery, Endolumenal), an approach for
treating weight regain post bariatric surgery (e.g., after gradual gastric pouch and stoma enlargement following Rouxen-Y gastric bypass [19–23]). The IOP is also in early trials
as the platform of access devices that facilitate the novel
Primary Obesity Surgery Endolumenal (POSE) procedure,
an approach that may provide a means of weight reduction
as effective as bariatric surgery, yet with even greater safety.
POSE has been performed successfully by both surgeons
and gastroenterologists in North America, Europe, and the
Middle East; to our knowledge, this study provides the first
formal English-language presentation of outcome data.
In the POSE procedure, stomach tissue is plicated in 8–9
locations in the fundus and in 3–4 in the distal body using
specialized suture anchors. The plicated areas mechanically
and physiologically restrict contact of ingested food with the
full surface area of the stomach. It is hypothesized that the
anchored plications may more rapidly activate gastric stretch
receptors in response to food, partially defunctionalizing the
fundus by limiting its ability to accommodate a meal [24–26].
Additional distal plications are expected to slow antral mill
contractions and delay complete gastric emptying, thereby
reducing hunger and initiating earlier and prolonged satiety
[27, 28]. By these — and perhaps other — mechanisms,
POSE may facilitate durable weight loss and comorbidity
improvement while not precluding other interventions.
Between February 28, 2011 and March 16, 2012 in our
institution, the Centro Médico Teknon (Barcelona, Spain),
we performed the POSE procedure in a series of patients
with an initial mean body mass index (BMI, kg/m2) of 36.7.
We present our experience to date and 6-month outcomes
with the POSE procedure.
OBES SURG (2013) 23:1375–1383
Endpoints, Data Collection
Safety endpoints analyzed were minor and major complications. Operative time and duration of hospital stay were
recorded. The primary effectiveness endpoint was weight
loss at 6 months expressed as mean change from baseline in
absolute weight (AW) and BMI. In addition, percentage
excess weight loss (%EWL), and percentage total body
weight loss (%TBWL) were calculated. Percentage EWL
was calculated using a constant BMI of 25 kg/m2 to determine
ideal body weight (IBW): %EWL=(baseline AW−6-month
AW)/(baseline AW−IBW)×100; %TBWL was calculated as:
%TBWL=(baseline AW−6-month AW)/(baseline AW)×100.
Patients
Patients who considered undergoing the POSE procedure
underwent an informed consent process concluding with their
signing of the Ethics Board-approved consent form. To participate in the study, patients needed to present with a BMI in the
class I or II obesity range (World Health Organization [WHO]
[32]), or in the WHO class III range but be unwilling to undergo
a surgical procedure. As the procedure is new, patients with a
BMI between 30 and 40 were felt to be the best candidates to
provide the probable best outcomes for these lower- to midrange BMI patients while reserving standard bariatric procedures for patients with a BMI >40. Patients were required to be
>20 years of age and able to return to the hospital for all followup visits. Nutritional evaluation and psychological screening
provided confirmation of patients’ ability and willingness to
comply with the post-procedure diet and exercise program.
Patients paid independently for their procedures with no USGI
financial support provided for either the patient or clinician.
Patients were excluded if they were non-ambulatory or
had significant mobility impairment; if they had a known
and untreated hormonal or genetic cause for obesity; or, if
they had work hours, family obligations, or transportation
issues that could interfere with their return for all scheduled
evaluations.
Methods
Endoscopic Equipment
Study
In 2011, our endoscopic group in the Centro Médico Teknon
undertook a clinical study of the POSE procedure. The
study was of a prospective, single-center, non-comparative
observational design. The study protocol and case report
form stipulate good clinical practices (GCPs) as defined in
ISO EN 14155–1 and −2 [29, 30]. All patients were asked to
provide written informed consent prior to surgery in accord
with Teknon Ethics Board requirements and GCP guidelines
outlining patient protections stipulated by the Declaration of
Helsinki [31].
The incisionless, flexible endosurgical TransPort® Endoscopic
Access Device (USGI Medical) provides a stable platform
through which to work in the operative site. The TransPort
has four working ports that deploy an endoscope and three
specialized instruments: the g-Prox EZ® Endoscopic Grasper, a
flexible shaft with a jawed gripper for mobilizing and approximating a tissue fold; the g-Lix™ Tissue Grasper, a flexible
probe with a distal helical tip designed to assist the g-Prox in
capturing target tissue (Fig. 1a); and the g-Cath EZ™ Suture
Anchor Delivery Catheter, a catheter system with a needle at its
distal tip that, after advancement through the lumen of the
OBES SURG (2013) 23:1375–1383
Fig. 1 a Incisionless Operating Platform™ with TransPort® Endoscopic Access Device; b g-Cath EZ™ Suture Anchors; c schematic of
anchors holding plicated tissue permitting serosal approximation.
gProx, penetrates the mobilized target tissue, installs a pair of
pre-loaded Suture Anchors™, and cinches the anchored tissue
fold (Fig. 1b). The mesh suture anchors (pledgets) were
designed to distribute holding forces across the plication contact points in order to reduce the tissue trauma often associated
with sutures, thereby facilitating postoperative healing and
increasing procedure durability.
Surgical Technique
The POSE procedure was conducted in the operating room
using general anesthesia.
1377
Prior to intubation of the Transport, a standard gastroscopy was routinely performed to aspirate any accumulation
of fluid, as well as to verify that the pathology of the
anatomy was not irregular. The shape of the fundus was
noted, as this may affect the number of suture anchors
placed. The TransPort was inserted transorally and advanced
into the stomach. Visualization was achieved through the
TransPort with a small-diameter endoscope.
Suture-anchor plications were placed in the fundus and
distal body with the intent of reducing fundal accommodation and inducing antral dysmotility following meal consumption. To achieve each plication, target tissue was
grasped with the g-Lix and pulled and guided into the jaws
of the g-Prox. The g-Prox jaws were closed. After insertion
of the g-Cath system through the g-Prox lumen, the g-Cath
needle tip was advanced through the tissue fold and a suture
anchor deployed on each side of the tissue fold to approximate it; the suture anchors were cinched to an appropriate
tension. The proximal end of the suture was cut, leaving the
cinched anchor pair holding the apposed tissue (Fig. 1c).
After the first 15 cases, a technical improvement was by
made by cutting the sutures using the g-Prox instead of an
external scissors; this resulted in shortening the operative
time by 20 min in the ensuing cases. The g-Cath system
facilitated creation of secure plications without the challenge of endoscopic knot tying and the associated potential
tissue trauma.
Generally, 8–9 plications in the fundus proved sufficient
to reduce the surface area significantly. The orientation of
the g-Prox influenced alignment of the tissue fold once the
g-Cath needle was deployed. When the needle passed from
anterior to posterior, the fold was created at a medial to
lateral angle; the second pair of suture anchors was placed
approximately 2–3 cm from the previous pair, creating and
continuing a tissue ridge. This approach appeared to be the
quickest method of setting up subsequent anchor placements
and providing visual confirmation of fundal surface reduction. After placing four suture anchors, the tissue ridge
routinely extended to the lateral limit of the fundus; a second
row, anterior to the first row, was then started and completed
using four suture anchors. More anchors may be necessary
to achieve a complete reduction; however, the two tissue
ridges appeared to confer the greatest fundal surface contraction using the fewest sutures. Following placement of
the fundal tissue anchors, we ensured that the apex of the
fundus was pulled down to the same level as the gastroesophageal junction.
With the aim of disrupting the gastric antral mill, 3–4
additional plications were placed in the distal body, creating
a tissue ridge near the mouth of the antrum opposite the
angular incisure. After creation of a tissue ridge in the distal
body, the instruments and TransPort were removed, and
anesthesia withdrawn. A standard gastroscope was routinely
1378
used following the procedure to view the plications and
verify that there was no bleeding. The CO2 was aspirated
and the stomach collapsed prior to final extubation.
Postoperative Care
In the first 4 weeks post procedure, patients were placed on a
customized, calorie-restricted diet (per day: 800 calories, minimum 50–70 g protein, maximum 30 g fat, ≥64 oz fluids) that
transitioned from liquid to pureed foods, to soft solids, and
then full solids in the sixth week. In the sixth week, patients
were counseled to maintain their daily diet at 1,200 calories.
Walking exercise (10–15 min 2–3 times/day) was encouraged
in the first 4 postoperative weeks, with instructions to increase
exercise in the fifth week to an investigator-approved aerobic
regimen of 35–45 min 5 times/week.
Because this procedure was new to us, we preferred a
rigorous and cautious follow up schedule: Follow-up visits
were performed at 1, 2, and 3 weeks, and at 1, 2, 3, 4, 5, and
6 months. Upper GI series were not performed as a rule.
Statistical Analysis
OBES SURG (2013) 23:1375–1383
Table 1 Patient baseline characteristics
Characteristic
Value
Mean±SD (rangea)
N=45
Age (years)
Height (m)
AW (kg)
BMI (kg/m2)
IBWb (kg)
EWc (kg)
Gender, N (%)
Male
Female
BMI by WHO class, N (%)
Class Id (30.0–<35)
Class II (≥35.0–<40)
Class III (≥40.0)
43.4±9.2 (21.0–64.0)
1.7±0.1 (1.5–1.8)
100.8±12.9 (75.5–132.5)
36.7±3.8 (28.1–46.6)
68.7±5.8 (59.0–81.0)
32.1±10.7 (8.3–60.3)
11 (24.4)
34 (75.6)
15 (33.3)
24 (53.3)
6 (13.4)
AW absolute weight, BMI body mass index, IBW ideal body weight, EW
excess weight, WHO World Health Organization weight classifications
a
Range=min–max
b
IBW (kg)=height (m)2 ×25 kg/m2
EW (kg)=AW (kg) – IBW (kg). (Determination of EW for this study
was based on an “ideal” body weight [IBW] equivalent to a BMI of
25 kg/m2 – the cut-off point that defines overweight in the current
WHO classification)
c
Statistical analyses were performed using SAS® software v.
1.9 (SAS, Cary, NC). Patient baseline characteristics and
perioperative outcomes were summarized; continuous parameters were reported as number of non-missing observations (N), mean, standard deviation (SD), and range.
Categorical parameters, both at baseline and postoperatively, were reported as count and percentage. Continuous outcome variables were generally reported as mean, SD, and
range. Mean change values at 6 months in AW and BMI
were calculated along with corresponding 95 % confidence
intervals (CIs) for mean differences. Also, 95 % CIs were
calculated for mean %EWL and mean %TBWL at 6 months,
as well as for subgroup %TBWL means at 1, 3, and
6 months. Measures of change from baseline were analyzed
using paired-samples t-tests. Between-group comparisons
(i.e., %TBWL subgroup analyses) were carried out using
analysis of variance (ANOVA) for independent samples.
Scatter diagrams and correlation analysis were used to explore %TBWL and %EWL relationships with baseline BMI.
Statistical significance was set at p<0.05.
d
Two patients had BMI <30 (i.e., 28.1 and 29.9 kg/m2 )
baseline BMI was 36.8. There were 15 patients with class
I obesity (33.3 %), 24 patients with class II obesity (53.3 %),
and six patients with class III obesity (13.4 %).
Operative Outcomes
All POSE cases were performed by experienced endoscopists
with no intraoperative adverse events, no conversions or failed
procedures, and no postoperative re-hospitalizations. The
mean number of total suture anchors placed was 11.3±1.1
(8–14) (Table 2). The mean operative time was 69.2 ±
26.6 min. Following the procedure, 100 % of patients reported
less hunger and earlier satiety. All patients were discharged
between 12 and 24 h.
Weight Outcomes
Results
Baseline Patient Characteristics
As shown in Table 1, the majority of patients were female
(75.6 %). The mean age was 43.4±9.2 years (21–64). Mean
AW was 100.8±12.9 kg (75.5–132.5); height, 1.7±0.1 m
(1.5–1.8); and BMI, 36.7±3.8 (28.1–46.6). The median
Postoperative weight outcomes were available in 80.0 %
(27/34) of protocol-compliant patients at the 6-month time
point. Paired samples t-tests indicated that obesity parameters were significantly reduced (Table 3). Mean AW (kg)
was 87.0 ± 10.3 compared to 103.3 ± 13.1 at baseline, a
within-patient mean change of −16.3±7.1 (95 % CI, −19.1 to
−13.5; p<0.001). Percentage TBWL was 15.5±6.1 (95 % CI,
13.1 to 17.9). BMI was 31.3±3.3 relative to a baseline measure
OBES SURG (2013) 23:1375–1383
1379
Table 2 Perioperative outcomes
Characteristic
Value
Mean±SD (range)
(N=45)
Procedure duration, min
Number of anchors, fundus
Number of anchors, distal body
Number of additional anchors
Total number of anchors
69.2±26.6 (32.0–126.0)
8.2±1.1 (5.0–10.0)
3.0±0.5 (2.0–5.0)
0.0±0.2 (0.0–1.0)
11.3±1.1 (8.0–14.0)
of 37.2±3.9, a mean change of −5.8±2.5 (95 % CI,
−6.8 to −4.8; p<0.001); %EWL was 49.4±21.5 (95 % CI,
40.9 to 57.9).
Subgroup analyses of weight loss (i.e., %TBWL) by
gender, age, and BMI at 1, 3, and 6 months following POSE
are presented in Table 4. Due to the relatively small number
of class III patients (n=6) in the study, patients were divided
into two BMI groups: class I obesity (30.0 to <35.0) vs.
class II (≥35 to 40) and above. Analyses indicated that there
were no significant differences in weight-loss outcomes
between males and females, age groups (i.e., <40, ≥40 to
<50, ≥50 years), or between BMI groups (i.e., BMI <35.0,
BMI ≥35.0) across time points.
Scatter diagrams and correlation analyses were used to
further examine the relationship between baseline BMI and
the efficacy of the POSE procedure as measured by %TBWL
and %EWL at 6 months. Percentage TBWL and EWL correlated with baseline BMI at r=0.29 (p=0.14), and r=0.23 (p=
0.25), respectively. Although the relationship between baseline BMI and weight outcome was not statistically significant,
several interesting observations were noted—particularly with
regard to patients with BMI<35 vs. those with BMI≥35.
Seventy-five percent (6/8) of BMI<35 patients, and 95 %
(18/19) of BMI≥35 patients experienced greater than 5 %
TBWL at 6 months. Also, 75 % (6/8) of BMI<35 patients,
and 89.5 % (17/19) of BMI≥35 patients experienced greater
than 25 % EWL over the same period. POSE patient 6-month
%TBWL and %EWL correlated at r =0.83 (p <0.001).
Overall, %TBWL and %EWL correlated at a mean r=0.69
(range: 0.61–0.83) across follow-up time points. Generally
speaking, both BMI subgroups trended upward along percentage weight-loss outcome measures.
Complications
There was no mortality in the series and only two minor
adverse events as defined by the American Society for Gastrointestinal Endoscopy (ASGE) [33]. Post POSE, there was one
case of low-grade fever that resolved with oral antibiotic
treatment and another patient who returned to the hospital on
the second postoperative day with chest pain; complications
from the procedure and cardiovascular issues were ruled out
and the patient was sent home. Minor postoperative side effects
included sore throat, stomach pain, nausea, and chest pain
(Table 5). There were three cases of vomiting that resolved
within the first 12 h with no requirement of additional hospital
stay. One patient was discharged on the second postoperative
day for her personal convenience, not due to medical necessity.
There was no device-related morbidity.
Discussion
Current study results demonstrate the clinical safety and
effectiveness of the POSE procedure for primary weight
loss in a small cohort of obese patients. In addition to
achieving significant weight loss with no major complications, POSE required just over an hour of procedural time,
incurred no incisions or scars, and resulted in a fast recovery
time and brief hospital stay.
Table 3 Mean weight loss at 6 months
Parameter
Mean±SD (range)
(N=27)
Mean change±SD
95 % CI
p valuea
AW (kg)
BMI (kg/m2)
EWLc (%)
TBWLe (%)
87.0±10.3 (68.0–111.5)
31.3±3.3 (25.1–38.6)
49.4±21.5 (13.7–98.4)
15.5±6.1 (2.4–24.5)
−16.3±7.1
−5.8±2.5
__
__
−19.1, −13.5b
−6.8, −4.8b
40.9, 57.9d
13.1, 17.9‡
<0.001
<0.001
__
__
AW absolute weight, BMI body mass index, EWL excess weight loss, IBW ideal body weight, TBWL total body weight loss
a
Paired samples t-test assessing change from baseline
b
95 % CI of mean difference
c
95 % CI of the mean
d
EWL (%)=(AW change [kg]/(baseline AW [kg]−IBW [kg]))×100
e
TBWL (%)=(AW change [kg]/baseline AW [kg])×100
1380
OBES SURG (2013) 23:1375–1383
Table 4 Total body weight loss by month and subgroup
Month
Parameter
N
Mean±SD (range)
(%)
Month 1
TBWL by gender
Females
32 8.1±2.4
Males
11 9.4±1.5
TBWL by age (years)
<40
16 8.4±1.9
≥40 to <50 15 8.2±2.7
≥50
12 8.6±2.2
TBWL by BMI (kg/m2)
<35.0
13 8.3±2.8
≥35.0
30 8.4±2.0
Month 3
TBWL by gender
8
19
p value
(4.4–14.3)
(6.4–11.4)
7.2–8.9
8.4–10.4
0.09
(5.3–11.4)
(4.4–14.3)
(5.1–11.4)
7.4–9.4
6.7–9.7
7.2–10.0
0.93
(4.4–14.3)
(5.3–11.4)
6.6–10.1
7.7–9.2
0.90
10.8–14.3
13.0–17.1
0.12
10.2–15.3
10.8–17.1
11.1–14.8
0.75
9.4–14.5
12.0–15.5
0.22
11.4–17.5
14.6–22.4
0.14
12.0–19.1
8.7–22.0
10.6–20.7
0.99
7.7–19.0
13.6–19.2
0.24
Females
29 12.6±4.6 (4.0–20.3)
Males
10 15.1±2.9 (9.3–19.7)
TBWL by age (years)
<40
15 12.8±4.6 (4.1–20.3)
≥40 to <50 13 14.0±5.2 (4.0–19.9)
≥50
11 12.9±2.7 (7.3–16.1)
TBWL by BMI (kg/m2)
<35.0
12 11.9±4.0 (4.0–17.6)
≥35.0
27 13.8±4.4 (4.1–20.3)
Month 6
TBWL by gender
Females
20 14.5±6.4 (2.4–24.5)
Males
7
18.5±4.2 (11.6–23.2)
TBWL by age (years)
<40
11 15.6±5.3 (7.8–23.7)
≥40 to <50 8
15.3±8.0 (2.4–24.5)
≥50
8
15.6±6.1 (4.5–21.4)
TBWL by BMI (kg/m2)
<35.0
≥35.0
95% CI
a
13.3±6.7 (2.4–21.0)
16.4±5.8 (4.5–24.5)
b
TBWL total body weight loss, BMI body mass index
a
95% CI of the mean
b
Analysis of variance (ANOVA) for independent samples
Table 5 Postoperative
complications
Complication
N (%)
(N=45)
Fever
Sore throat
Stomach pain
Nausea
Vomiting
Chest pain
1 (2.2)
5 (11.1)
15 (33.3)
6 (13.3)
3 (6.7)
2 (4.4)
There was no mortality in the current study, whereas,
≥30-day mortality in all categories of bariatric surgery (from
purely restrictive to malabsorptive-restrictive to purely
malabsorptive procedures [34]) is 0.1 % to 0.28 % according
to meta-analysis [35]. In the POSE cohort, there were no
(0.0 %) major perioperative complications, only minor complications that cleared rapidly, while the overall complication rate
for restrictive and malabsorptive-restrictive bariatric procedures
has been estimated at 1.1 % to 2.7 % [36].
Although current POSE findings at 6-month follow-up
are preliminary and based on a small cohort, POSE appeared
equally effective for both sexes and for all age and BMI
groups studied. In relation to the recent interest in bariatric
treatment for low-BMI patients, both BMI groups (baseline
<35 and ≥35) trended upward along percentage weight-loss
outcome. However, lower-BMI POSE patients appeared to
experience relatively higher %EWL than higher-BMI patients; conversely, low-BMI patients demonstrated slightly
lower %TBWL over time than their higher-BMI counterparts. These seemingly contradictory results are due to the
choice of outcome measure.
Several measures of weight loss have been employed in
the scientific literature, rendering comparison of outcomes
within and across bariatric methodologies challenging. Reports of medical/nonsurgical therapies typically present actual weight loss or %TBWL; whereas, weight-loss results
for primary bariatric surgical procedures are mainly reported
as %EWL. Further, %EWL has been reported in the literature using two different methods [37]. The EWL calculation
reported most frequently utilizes the Metropolitan Life
Tables (MLT) to determine ideal body weight; whereas,
the second method uses a constant BMI of 25. In the current
study, the second measure of EWL was employed, as some
have suggested it is a more accurate representation of ideal
body weight due to the narrow and outdated range of anthropometric measurements upon which the MLT classifications are based [37–39]. Practitioners in the emerging area
of endoscopic bariatric procedures, such as the ASGE and
the American Society for Metabolic and Bariatric Surgery
(ASMBS) Task Force, are discussing the most apt measurement(s) with which to compare weight-loss effectiveness
across endoscopic procedures and in relation to bariatric
and non-interventional approaches [40].
In the current study, the mean 6-month POSE TBWL was
15.5 %, which is significantly better than the minimum 5.0 %
TBWL threshold recommended for achievement of weightrelated comorbidity resolution [39] and congruent with the
approximately 15.0–25.0 % TBWL seen in systematically
reviewed analyses of patients following very low-calorie diet
and exercise programs for <6 months (although fewer than
9.0 % of the diet and exercise regimen patients maintained this
weight loss at 1 year) [41, 42]. Using the MLT calculation of
EWL for POSE at 6 months—40.0 %—POSE results were
OBES SURG (2013) 23:1375–1383
comparable to the 1-year laparoscopic adjustable gastric
banding mean EWL of 42.6 % reported by recent metaanalysis using the MLT standard [43]. At 6-month followup, more than 80.0 % of POSE patients had achieved ≥25 %
EWL, and the overall POSE patient mean EWL as calculated
by either metric (MLT [40.0 %] or BMI 25 as ideal end point
[49.4 %]) far exceeded the minimum 1-year goal of 25.0 %
EWL recommended for endoscopic bariatric therapies by the
ASGE/ASMBS Task Force [40]. Patients in the current POSE
cohort who have reached the 9- and 12-month time points
have continued their weight-loss trend with no complications.
There are several other new endoscopic procedures for
short- and long-term primary weight loss that take different
mechanical approaches, ranging from gastric-volume reduction (e.g., the EndoCinch, Bard, Murray Hill, NJ; and TERIS,
BaroSense, Redwood, CA) to exposure of the jejunum to
partly digested nutrients (EndoBarrier, GI Dynamics, Lexington, MA). In initial studies, these procedures have shown
19.9–46.0 % EWL at 6 months to 1 year [44]. Early trials of
TERIS and Endo Barrier resulted in the following major
Fig. 2 Endoscopic view of fundal and distal body plications immediately post POSE.
1381
Fig. 3 Endoscopic view of suture anchor stability at 6 months following POSE.
complications: gastric perforation, pneumoperitoneum requiring percutaneous intervention [45], device migration, obstruction, bleeding [46, 47]).
The TERIS procedure and the POSE procedure using the
IOP differ in several important respects. The TERIS is an
implant-based procedure, with plastic anchors placed near
the cardia to create an internal restriction similar to a gastric
band. The TERIS devices acquire tissue via suction, which
has been found to provide tissue plications of inconsistent
size and depth. The POSE procedure using the IOP is not
implant-based, and instead uses sutures and pledgets to
secure durable folds in gastric tissue. The IOP acquires
tissue using a grasper with a long, 33-mm jaw that allows
full-thickness bites to be secured under direct visualization.
The POSE procedure itself is not thought to be restrictive in
its mechanism of action, and involves plicating the fundus
and distal gastrum of patients to induce a physiological
response: earlier fullness and prolonged satiety. Further
investigation of these endoscopic devices and procedures
is required.
More study is required to understand the mechanisms of
action involved in POSE weight loss using the method of
multiple individual tissue plications. The safest and most
effective locations for gastric anchor placement in POSE are
still being refined. Also unknown is the minimum number
of suture anchors that would provide maximum weight-loss
effectiveness in the fundus and distal body.
A weight-loss approach such as the POSE procedure
depends for its success upon creating the most favorable
conditions for GI wound healing. GI tissue healing following suturing requires incorporation of the muscular, serosal,
and submucosal layers to trigger an inflammatory response
sufficient to promote early proliferation of collagen at the
plication site [48, 49]. The snowshoe-shaped suture anchors
deployed through the g-Cath appear to be an attractive
1382
option relative to traditional suturing to achieve tissue apposition. When sutures are cinched across gastric tissue folds to
form plications, overtightening may cut through tissues, precipitating wound dehiscence [50]. As demonstrated in a shortterm preclinical study comparing four suture anchor designs
used to make full-thickness gastric plications, the expandable
suture anchors provided what appeared to be a firm, nondamaging amount of compression, pliant in response to the
inflammatory process that facilitated durable tissue remodeling [51]. In the current study, Fig. 2 shows an endoscopic view
of fundal and distal body plications immediately post POSE;
Fig. 3 shows suture-anchor stability at the 6-month postPOSE study end point.
The POSE procedure can be performed by a well-trained
endoscopist or bariatric surgeon. As with bariatric surgical
procedures, POSE should be undertaken within a supportive,
comprehensive, obesity management program, and should be
viewed as a tool for weight loss and stimulus to behavior
modification rather than as an independent solution to obesity.
A weakness of this study was that it was conducted on a
small patient series without a control group. Although data
on comorbidities and quality of life were collected throughout the study, they were not collected uniformly and, thus,
could not be appropriately analyzed and described as part of
the 6-month findings; follow-up reports should include these data. As POSE is thought to have a significant impact on
hunger and satiety, objective evaluations of these parameters
would be of value in future investigations.
To our knowledge, this is the first peer-reviewed publication of POSE weight-loss outcomes in obese patients.
Initial results are encouraging. Marked weight loss with
POSE with only minor perioperative side effects compares
favorably with outcomes of restrictive bariatric surgical procedures while providing a better safety profile over the short
term. POSE may also provide a novel means of early intervention in overweight patients’ progression into obesity and
increasing comorbid illness. Long-term follow-up of this
series and additional rigorous studies of POSE for weight
loss are required to evaluate its safety, effectiveness, and
patient acceptance.
Acknowledgments We thank Dror Rom, PhD, Prosoft Software,
LLC (Wayne, PA), for performing the statistical analysis, and T.W.
McGlennon, M3, LLC (Maiden Rock, WI) for statistical consultation.
We also thank Maribel Sanchez for nutritional consultation during the
study, Marta Lasaosa for administration, Sandra Andres for endoscopic
nursing, Dr. Monica Prat for psychiatric consultation, and Sonia Oliva
for psychological evaluation.
Disclosure The clinical study at the Teknon site was not financially
supported and was conducted independently by Teknon’s physicians.
Manuscript development was supported by USGI Medical, USA. J.N.
Buchwald is the director and chief scientific research writer at
Medwrite LLC, a CRO under contract with USGI. Manuscript development was supported by USGI Medical, Inc.
OBES SURG (2013) 23:1375–1383
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