Sleeve gastrectomy (SG) is a vertical left gastrectomy of the body and fundus to create a long, narrow tubular gastric sleeve along the lesser curvature that reduces the size of gastric reservoir to 80 - 120 cc.
SG was developed in 1988 as the initial procedure in a staged approach to patients with morbid obesity  .
However, the initial promising results of SG in terms of weight loss and resolution of comorbidities have rendered it popular not only as a first stage procedure but also a primary bariatric surgery. SG was described as an isolated procedure in 1993 by Johnston et al.  with a minimally invasive alternative developed in 1999. SG is now considered as a newer stand-alone operation being performed with increasing frequency. In 2011, it occupied over 25% of bariatric procedures worldwide, which became the second most commonly performed bariatric procedure after RYGB.
2. Sleeve Gastrectomy and GERD
The second international Consensus Summit for Sleeve Gastrectomy reported that the mean prevalence of postoperative GERD was 6.5% ranging from 0 to 83%  .
Cottan et al.  reported a series of 126 patients who underwent SG and found a 20% incidence of GERD at 12 months postoperatively. Hamoui et al.  reported 131 SG patients with a 12.7% incidence of GERD at 13 months; Nocca et al.  reported 163 SG patients with an 11.8% incidence of GERD at 24 months; and Soricelli et al.  reported 264 SG patients with a 7.8% incidence of GERD at 24 months.
SG is regarded to induce or exacerbate GERD in general, although there is a debate regarding whether SG induces or treats GERD.
2.1. Lower Esophageal Sphincter after Sleeve Gastrectomy
In a recent review of the literature, an increase in reflux symptoms after SG was reported in four studies  , while seven studies reported a reduction in GERD symptoms postoperatively  .
Multiple anatomical or physiologic factors have been proposed and identified that could contribute to the worsening of reflux or the de novo development of GERD after SG. Several studies   have suggested that the increased incidence of GERD in relation to SG may be due to a significant decrease in lower esophageal sphincter resting tone and pressure after surgery.
Decreasing in lower esophageal sphincter pressure (LESP) from disruption of phrenoesophageal ligament, partial resection of sling fibers could be the cause of GERD. The main function of the LES is to prevent the retrograde movement of gastric content into the esophagus. However, if the normal function of this sphincter is altered, such as prolonged lower esophageal sphincter relaxation, a hypotensive lower esophageal sphincter, or anatomic disruption of the gastroesophageal junction as a hiatal hernia, gastroesophageal reflux of different severity can occur.
The anatomy of LES has been carefully evaluated by Korn et al.   showing the presence of 2 different fibers: “clasps” and “sling”. The clasp fibers are located at the right portion of the sphincter and are the final prolongation of semicircular fibers. The sling fibers are located at the left site of the sphincter and are anchored at the antrum. In SG, gastric section should start 1 - 2 cm from the esophagogastric junction to avoid or to diminish the production of leak. If gastric section is done 3 or more cm from the EG junction, probably most sling fibers are divided, which may affect LES pressure and pathologic acid reflux may appear.
Therefore, I think manometry and pH metry should be performed as routine examination to make a diagnosis and assessment of GERD pre and postoperative.
Braghett’s group  reported manometric changes occur in LES after SG. Mean LES resting pressure (LESRP) decreased significantly after SG from 14.2 ± 5.8 to 10.5 ± 6.06 mm・Hg (p = 0.01). 15% of patients presented normal LESRP (23.1 ± 3.7 mm・Hg) and 85% were hypotensive, with a mean resting pressure of 8.3 ± 2.6 mm・Hg. GIF findings also are erosive esophagitis and cardia dilatation in these patients .Burgerhart  observed a decrease in LES resting pressure from 18.3 ± 9.2 to 11.0 ± 7.0 mm・Hg (p = 0.02) measured by high resolution manometry. Tai et al.  demonstrated significant increases in GERD (47%), erosive esophagitis (67%), and hiatal hernia (27%) after SG.
Klaus and Weiss  suggested that preoperative manometry should be routinely performed and that patients with a lower esophageal sphincter pressure should not undergo SG.
The narrow sleeve (high-intragastric pressure), smaller antrum and stricture of incisura angularis could be other causes.
The size and configuration of the gastric sleeve may also have a significant effect on the risk for postoperative GERD. An overly narrowed or strictured sleeve may result in reflux and decreased esophageal acid clearance  . Finally, the presence of a hiatal hernia that is not recognized or that develops over time may result in the development of significant reflux symptoms. The importance of these anatomical factors in determining the risk of GERD after SG is highlighted by several series that describe technical details of the procedure that can reduce the incidence of postoperative GERD. These details include attention to the sleeve size and volume, avoidance of narrowing the gastric body or pylorus, and identification and repair of all associated hiatal hernias  . One series demonstrated that attention to crural repair during SG resulted in GERD remission in 73% and a decrease in the development of de novo GERD from 23% to 0%  . These series suggest that technical modification may have a major role in reducing the risk of postoperative GERD with SG.
Most surgeons recommend the approximation of the crura if hiatal hernia is found during SG. Dissection to the posterior is necessary to inspect and repair the hiatal hernia.
2.2. Case Reports of Esophageal Adenocarcinoma after SG
Esophagogastric cancer after bariatric procedures was reported in less than 40 cases, and to our knowledge, only three cases of esophageal adenocarcinoma after SC have been published. Sheepers et al.  described the case of 57 years woman who was submitted for a SG and was diagnosed with esophageal adenocarcinoma four months after SG. Sohn et al.  44 years woman who underwent SG developed an adenocarcinoma of the gastroesophageal junction 2.5 years after SG. Surprisingly, in both cases the SG was performed without previous endoscopic evaluation, making it impossible to rule out the presence of early or premalignant esophageal lesions. As a matter of fact, in the first case, the esophageal adenocarcinoma diagnosed four months after SG had been probably present at the time of SG. Wright et al.  reported that 48 years male with morbid obesity and normal preoperative endoscopy and esophagogram who underwent a laparoscopic SG and developed an esophageal adenocarcinoma after five years.
SG is an operation which may produce pathologic reflux of acid as well as reflux of duodenal content due to decrease LES and narrowed or strictured sleeve.
Therefore preoperative manometry and GIF should be routinely performed. Patients with a lower LES or preexisting sever GERD should be taken into consideration during patients counseling and selection of the optimal bariatric procedure. Moreover, postoperative GIF should be performed to detect GERD, erosive esophagitis and Barrett’s esophagus.
Further study is clearly indicated to clarify the role of preoperative GERD in the selection of bariatric procedures, to evaluate the effect of SG on reflux potential and GERD, and to identify technical factors that may minimize the risks of persistent or de novo GERD after SG.
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