ABSTRACT surgeon. Data regarding demographics, calibrating devices and



 Sleeve gastrectomy (SG) is one of the most common
procedures performed for weight loss. 
Many seek the “perfect sleeve” with the notion that the type of
calibrating device affects sleeve shape, and this in turn will affect outcomes
and complications.  Two major concerns
after SG are amount of weight loss and acid reflux. Our aim was to determine if the various calibration methods
could impact sleeve shape and thereby allow for better outcomes of weight loss
and reflux.


retrospective chart review was performed of 210 patients who underwent SG and
had postoperative upper gastrointestinal study (UGI) from 2011 to 2015 in a
single center by a single (fellowship-trained) bariatric surgeon. Data
regarding demographics, calibrating devices and clinical outcomes at 1 year
(weight loss and de-novo acid reflux) were collected.  UGIs were reviewed by two radiologists
blinded to the clinical outcomes. Sleeve shape was classified according to a
previously described classification as tubular, dumbbell, upper pouch or lower
pouch. The types of calibrating devices used to guide the sleeve size
intra-operatively, were endoscopy, large-bore orogastric tube and fenestrated
suction tube.


hundred and ninety-nine patients met inclusion criteria (11 had no esophagram).
Demographics revealed age 45.76 +10.6 years, BMI 47+8.6 kg/m2,
and 82% female. Calibration devices used were endoscopic guidance (7.6%), large
bore orogastric tube (41.4%), and fenestrated suction tube (50.5%). Sleeve
shape was reported as 32.6% tubular, 20.6 % dumbbell, 39.2% lower pouch and
7.5% upper pouch (100% interrater reliability). No correlation seen with type
of calibration used. 62.0
% of patients had >50% excess weight loss at 1 year.  23% of patients
remained on PPI at 1 year (of which 43.3% did not have reflux preoperatively).  The lower pouch shape showed a trend toward
less reflux and more weight loss.  


study showed no clear association between uniformity of sleeve shape and the
type of calibration device used.  The
study showed a trend toward decreased reflux and improved weight loss with the
lower pouch shape, regardless of calibration device.


Keywords: sleeve
gastrectomy, shape, reflux, weight loss



        Obesity is a worldwide public health
concern, as obesity has doubled since 1980 with 1.5 billion adults considered
obese in 2008 1. In the United States, 34 percent of adults over 20
years of age are overweight, 34 percent are obese, and 6 percent are extremely
obese2. Obesity is directly associated with increased risk
of diabetes, hypertension and other chronic diseases, and places a huge burden
on public health.

     Over the past 20 years, bariatric surgery
has become a well-accepted solution to this public health concern. Although the
gastric bypass used to be the most commonly performed procedure for weight
loss, now the sleeve gastrectomy (SG) is one of the most commonly performed
procedures in the United States and even worldwide. The sleeve’s safety and
long term weight loss results in multiple studies have been widely proven. In
addition, surgeons find the procedure to be technically simpler than the
gastric bypass with a shorter operative time. 3-6  That being said, there is wide
variability in technique of sleeve creation.7

     As surgeons have gained experience with
the sleeve, two aspects have been identified as primary concerns for the
surgeon: effectiveness of weight loss and avoidance of postoperative
reflux.  Reflux has been a surprising
unintended consequence of sleeve gastrectomy in several studies.8 .  The reason
for this is unclear.  Possibilities
include increased pressure within the lumen of the remaining stomach,
increasing the susceptibility of acid reflux 9.  Other studies
suggest that disruption to angle of His and resection of sling fibers at the
hiatus may play a role in the creation of reflux.10 Thus many studies have been done to further evaluate
how to minimize the reflux seen after sleeve while maximizing weight loss.11

            This brings one to the notion of the
perfect sleeve. Few studies have looked at the final sleeve shape as it relates
to outcomes after weight loss surgery. There has been suggestion that the shape
may affect reflux. 12-13 Is there an ideal shape to the sleeve that optimizes outcomes?  Also does the calibration device impact the
final shape of sleeve attained? The purpose of this study is to determine if
the calibration device impacts the uniformity of the sleeve that is created.  Also, we sought to determine whether the final
shape of the sleeve impacts persistent postoperative reflux and excess weight
loss (EWL) after the procedure. 

Materials and Methods:

     A retrospective chart review was performed
of 210 patients who underwent SG from January 2011 to September 2015 in a
single center by a single surgeon who is board certified and did
fellowship-trained bariatric and endoscopic surgeon, and has been practicing
bariatric surgery for the last ten years, performing around 200 different
bariatric procedures per year in a center of excellence in bariatric surgery
that is accredited by the MBSAQIP of the American College of surgeons.

.  All patients
underwent a postoperative upper gastrointestinal study (UGI) with water soluble
contrast on the first day after surgery. Those who did not have a study were
excluded. As the study
was a retrospective chart review we did not calculate required sample size. Data regarding demographics, calibrating devices, and
clinical outcome at 1 year were collected. (Table 1) Postoperative weight loss
data were expressed as % of excess weight loss (EWL) (recommended assessment
tool by the American Society of Metabolic and Bariatric Surgery) 14.  Stringent
definitions were used to define de novo reflux and “successful” weight loss. De-novo
reflux, was defined as patients who remained on proton pump inhibitors
(PPI) at the one year postoperatively but had no prior history of reflux or PPI
use prior to weight loss surgery.  EWL
was considered successful in patients who lost >50% of EWL at the end of the
first year. This study was approved by the
Institutional Review Board of our center (IRB No. 12-15-34).


Only patients who underwent primary laparoscopic
sleeve gastrectomy were included. The technique was standardized. A 4-trocar
approach (one 15mm, one 12mm and two 5mm) was used. The dissection started
along the greater curvature of the stomach, using ultrasonic energy to take
down the short gastric arteries. The fundus is fully mobilized and the left
crus is exposed. The types of calibrating devices used to guide the sleeve size
intra-operatively were: endoscope (approximately 32 French), large bore
orogastric tube (32-36 French) and fenestrated suction tube (36 French). The
choice of calibration tube used was at the discretion of the surgeon as the
practice evolved.  Stapler firing began 5
cm proximal to the pylorus and care was taken to avoid narrowing at the
incisura.  This staple line proceeded to
the angle of His. The calibration device was used as a guide for creation of
the sleeve.  Bio-absorbable
buttressing material was used for staple line reinforcement. Endoscopy was
performed intraoperatively after the sleeve was completed to ensure hemostasis
and check for leaks. Drains were used rarely. The resected stomach was removed
through the 15mm trocar site, followed by closure of fascia and skin.

contrast upper gastrointestinal series (UGI) was performed for every single case
on postoperative day 1 (POD 1) to check for leaks and document the anatomy of
the sleeve at time of creation. This test was usually done in two positions:
flat and upright positions (60-degree plus). Patients ingested the
water-soluble contrast (Gastrografin), then fluoroscopic images were obtained,
using frontal and oblique projections. Images are taken in a special magnified
resolution. Patients are usually discharged later on POD 1.


Sleeve shape evaluation

      UGIs were reviewed by two radiologists,
independently, who were blinded to the clinical outcomes. Sleeve shapes were
classified according to a previously described classification as tubular (T-uniform
tube shaped stomach), dumbbell (DB-stomach with dilated portions proximally and
distally and narrow in the middle), upper pouch (UP-proximal dilation of the
sleeve) or lower pouch (LP-tubular upper portion of sleeve but retention of a
good portion of antrum).12  (Figure 1) Analysis of the association
between sleeve shape category, calibration device, and clinical variables was performed.



Data were analyzed using SAS University Edition (SAS
Institute Inc., Cary, NC, USA). Results are reported as mean or median ±
standard deviation (SD) for continuous variables. Clinical differences among
groups were determined by one- way ANOVA and t-test.  Comparisons were
determined by Fisher’s exact test. A P value <0.05 was considered significant. In order to control the factors affecting outcomes we performed logistic regression analysis.   Results              Of 210 patients, only 11 had no esophagram in the postoperative period. One hundred and ninety-nine patients were included in the study. The patients who competed 1 year of follow up were 113/199 (57%).  Demographics revealed mean age 45.76 + 10.6 years and preoperative BMI 47+8.6 kg/m2. 82% of patients were female. The comorbidities were: obstructive sleep apnea (86%), hypertension (67%), dyslipidemia (53%), arthritis (56%), depression (32%), diabetes type 2 (29%), hypothyroidism (18%), cardiovascular diseases (15%) and bipolar disorder (2%).  (Table 1)          Sleeve shapes were reported as 32.6% tubular, 20.6 % dumbbell, 39.2% lower pouch and 7.5% upper pouch (100% interrater reliability) by the radiologists. (Figure 2) Sleeve shape & calibrating device   Calibration devices used were endoscopic guidance (7.6%), large bore orogastric tube (41.4%), and fenestrated suction tube (50.5%). There was no relationship between resultant sleeve shape and type of calibrating device (P=0.395).  In a subgroup analysis, tubular (T) shape compared to Non-T Shape (UP, LP, DB) did not show statistical association between shape and calibrating device. However, T shape was reported more frequently in cases where endoscopic guidance was used (endoscopic 46.7 %, large bore tube 25.9% and fenestrated suction tube 36.0%, P=0.11). (Table 2). Similarly, lower pouch shaped sleeves also showed no correlation with the calibration device as compared to the other shapes, however was more frequently observed with the large bore and fenestrated suction tubes.  In addition, none of the devices showed any more uniformity of the resultant sleeve than the others. Sleeve shape & weight loss             The mean excess weight loss (EWL) at 12 months was 60.3%. The reason we chose 1 year follow up in this study, that many studies recently suggested that the maximum EWL happens at 1 year post-operatively.15-16 Regarding sleeve shape, the mean %EWL was 55.3% in tubular, 60.0% in dumbbell, 63.9% in lower pouch, and 61.7% in upper pouch shape group, respectively. There was no statistical difference between the shape of the sleeve and EWL (p=0.48), however the patients with a lower pouch showed a trend toward greater weight loss (Table 3). Sixty-two percent of patients who completed one year follow up had achieved successful weight loss (EWL>50% at 1 year).  We found no
statistically significant relationship between sleeve shape and EWL>50%
(p=0.34), but the lower pouch showed a trend toward greater success. (Table 3)    The logistic regression analysis revealed that only age was associated
with the outcome. (Table 5)



Sleeve shape & reflux symptoms

percent of patients reported ongoing PPI usage at 1 year, of which 43.3% did not
have reflux preoperatively (defined as the de-novo
reflux group). The sleeve shape did not show a clear association with the
presence of reflux or de-novo reflux
symptoms (p=0.7), however, a trend was observed toward less de-novo acid reflux in patients with the
lower pouch shape.
Logistic regression did not reveal a clear association between the outcome and
the investigated factors. (Table 6)

  Readmission rate was 1.8% (3/199), one case of leak, who was
simultaneously drained by laparoscopy and stented endoscopically. One case of
post-operative bleeding, and a case of pulmonary embolism those were managed


                 This study is one of the first
to look at the impact of calibration device on sleeve morphology, and the
impact of sleeve morphology on the outcomes of reflux and successful weight
loss at 1 year postoperatively. In this study, three calibration devices were
used to assess the uniformity of the shape of the resultant sleeve and no
device showed any consistent uniformity in the final sleeve shape. This finding echoes prior
studies where they also noted varying sleeve shapes were achieved despite using
a standard technique. 11,12 This suggests that surgeon technique or
patient factors may be involved in the final shape of the sleeve.  When looking at trends, we noted a trend
toward a tubular shape was more likely with endoscopic guidance, while the
lower pouch shape was more common when large
bore and fenestrated suction tubes were used. In the other studies the
most common shape was tubular. (Figure 3)

                   At 12-month follow up, the
mean EWL was consistent with most prior studies. What is notable is that of the
patients who achieved successful weigh loss at 1 year, 49% were from the lower
pouch group. Interestingly, in the first analysis of the MBASQIP database, it
was observed that the greater the distance from the pylorus, the initial staple
line was started, the more the weight loss.7 If we assume that going
further from pylorus will yield a lower pouch shape, this study may also
suggest that lower pouch shape may have better weight loss results.

studies looked at hunger scores with regard to sleeve morphology.  They noted the most hunger in the dumbbell
shaped morphology. Retention of more antrum may affect gastric emptying or
hunger that may then enhance weight loss. 
The satiety control was better in lower pouch group in comparison with
other groups.11 They postulate that the dumbbell group had the
greatest capacity, especially with the retained fundus and this explained the
greater hunger. 

                 The other important outcome noted
in this study and prior studies is the incidence of reflux with regard to
sleeve morphology. No statistically significant association could be associated
with sleeve shape, however, patients with the lower pouch shape demonstrated a
clear trend towards less de-novo reflux
symptoms. Other studies demonstrated a higher incidence of reflux (59%) but the
follow up was only 6 months and the definition of reflux was based on symptom
scores.11,12 They also found that higher severity of reflux happened
in upper pouch group versus other groups and least reflux symptoms happened in
lower pouch group. The retained fundus is clearly an undesirable outcome noted
in all studies as it is associated with a higher incidence of reflux.        

    In another study conducted by Lazoura et al, 3 morphological sleeve patterns
were noticed on UGI after SG, tubular 65.9%, superior pouch in 25.9% and
inferior pouch in 8.2%, they had higher incidence of early vomiting and
regurgitation in the tubular shape.13  Our series also supports the tubular and
upper pouch groups having the most reflux. The authors postulate that the
increased intragastric pressure in a tight tube, with impaired relaxation leads
to an increase in these symptoms.13
Not only sleeve shape can affect reflux, but many other factors including;
disrupting the sling fibers of the LES during SG, reduced gastric capacity with
intact reflux and altering the anatomy of angle of His, have an important role
in developing reflux after SG. 8, 17-18

We recognize that many
studies have been done suggesting improved or no change in reflux following the
sleeve, however, these three studies looking at sleeve morphology all
demonstrate evidence of ongoing reflux after the sleeve. In addition, our study
notes the least reflux in the lower pouch group and this is similar to other
studies. 11,12, One possible explanation is that in lower pouch
group, when we preserve the antrum totally or near totally, we may allow for a
proper gastric emptying mechanism, hence less reflux.      

                 So, based on
the findings of this study and prior studies, the authors conclude that the
lower pouch shape is the most desired outcome. 
Prior studies have suggested the tubular shape is the most desired
outcome. 11,12 All three of these studies looking at the tubular
shape note a higher incidence of reflux with this shape.  These studies all support that the retained
fundus leads to more reflux and may increase the capacity of the stomach
leading to more hunger.  Finally, the
least reflux and the most weight loss is seen in the lower pouch groups in this
and other studies. 11       


study does have some limitations. First,
the sample size was small which resulted in an inability to make steadfast
conclusions due to lack of power.  Since
this was retrospective, a prior power analysis was not done prior to
determining the use of sizing device. Therefore, a clear distinction in the
ability to make a consistently shaped sleeve cannot be clearly associated with
the type of device based on this study.  There
was 43% loss of follow up at one year, since many patients who come to our
center, are internationals or out of state. However, these data can be used for
planning future studies and definitely provide a basis for larger future
studies. Larger numbers may have achieved greater statistical
significance. The lack of significance may also be related to the stringent
definitions used for de-novo reflux and successful weight loss.
Additionally, 43% of patients were lost to follow up at one year.  Presumably those patients were doing well
with their weight loss and did not have reflux that necessitated a return to
the physician.  Furthermore, the
interpretation of UGI studies may have been limited by the static
pictures.  However, the radiologists had
100% interrater reliability suggesting this limitation was minimal.


is the first study to assess weight loss and de novo reflux at one year
postoperatively with regards to the shape of the sleeve. Although it showed no clear
association between the final sleeve shape and type of calibration device used,
it demonstrated a trend toward less reflux and improved weight loss with a
lower pouch shape regardless of calibration device.  This suggests that surgeon technique and
patient factors may be more important than the type of calibration device.  Further studies to refine technique are
needed to achieve the best outcomes with regards to maximizing weight loss and
minimizing reflux.

Ethical statement

All procedures involving human participants were
performed in accordance with the ethical standards of the institutional and/or
national research committee and with the 1964 Helsinki Declaration and its
later amendments or comparable ethical standards.


Informed consent was obtained from all individual
participants included in the study.





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