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Shaker et al. Mini-invasive Surg. 2025;9:27 https://dx.doi.org/10.20517/2574-1225.2024.105 Page 3 of 17

GERD development. Conversely, studies that report a decrease in GERD after SG suggest various
pathophysiologic mechanisms including weight loss and associated decrease in intra-abdominal pressure,
[16]
increased gastric emptying, and decreased acid production as a result of gastric fundus resection . Both
preclinical and clinical research indicate that the significantly altered anatomy following SG leads to
accelerated gastric emptying [17,18] , thereby counteracting refluxogenic forces.

A decrease in gastric compliance following resection of the fundus may also contribute to increased gastric
pressures after LSG. High-resolution impedance manometry (HRIM) post SG has shown that elevated
[19]
intragastric pressure and impedance reflux events are frequent events . A retrospective analysis of HRIM
conducted a median of 11 months after SG in 53 patients found that increased intragastric pressure after
water swallows occurred in 77% of cases, suggesting a reduction of gastric sleeve compliance. Despite this,
esophageal bolus clearance remained intact in all cases. Impedance reflux episodes occurred in 53% of cases,
of whom 40% reported typical GERD symptoms, compared to 5% among those without impedance reflux
episodes. In addition, there was a higher frequency of ineffective esophageal motility. No correlation was
found between increased intragastric pressure and impedance reflux episodes , suggesting that elevated
[19]
intragastric pressure is a manometric signature of SG rather than a causative factor in GERD.

Surgical technique may also play a role in the development of GERD after SG. Earlier studies showed a
decrease in baseline LES pressures following SG without antral preservation, which was attributed to the
[14]
division of LES sling fibers during transection of the gastric wall . Interestingly, more recent studies show
that hypotensive baseline LES pressures are not predictive of GERD after SG . In a single-center
[20]
retrospective study of 69 patients who underwent SG with antral preservation, high-resolution esophageal
manometry and 24-hour pH monitoring were performed. Although LES length was reduced postoperatively
(4.3 cm vs. 3.6 cm, P =0.00032), there were no significant changes in resting pre- and postoperative LES
pressures. Moreover, the sensitivity, specificity, positive predictive value, and negative predictive value of a
preoperative baseline hypotensive LES in predicting GERD (defined as a Demeester score > 14.72, regardless
of the presence of GERD symptoms) were only 31%, 70%, 52%, and 48%, respectively, suggesting that
[20]
resting LES pressure may not fully account for reflux . Finally, a meta-analysis of 7 studies that reported
technical details of the surgical procedure and GERD symptoms or esophagitis demonstrated a transient
protective effect of antral preservation, which was not preserved at longer time points .
[21]

The effect of SG morphology on weight loss and GERD symptoms has also been investigated. In one study,
upper gastrointestinal series were used to characterize SG morphology in 268 patients as Dumbbell (38%),
Lower Pouch (22%), Tubular (26%), or Upper Pouch (14%). An overall increase in the prevalence of GERD
symptoms, based on chart review, was observed postoperatively (68% vs. 48%, P < 0.0001), which was
further characterized as de novo (51%), persistent (28%), worsened (58%), or resolved (14%). While sleeve
morphology was associated with long-term weight loss, with the Dumbbell shape linked to less BMI
reduction, no association was found between sleeve morphology and any GERD outcomes .
[22]
Gastric tube abnormalities have been described following SG and are associated with the progression of
esophagitis. In a retrospective study of 459 patients post SG who underwent pre- and postoperatively
esophagogastroduodenoscopy (EGD), esophagitis was identified in 20% of the patients post SG, while
gastric abnormalities were identified in 28% of the patients. The most common alterations included gastric
dilation (16.1%), gastric twist (nearly 11%), neofundus (7.4%), and hiatal hernia (0.2%). Gastric tube
abnormalities were associated with the progression of esophagitis (P = 0.013), although no significant
[23]
association was found for individual abnormalities .