Surgical options for refractory gastroesophageal reflux disease following sleeve gastrectomy

Introduction

Obesity, affecting over one-third of Americans, can be treated with bariatric surgery, most commonly laparoscopic sleeve gastrectomy (LSG) (1,2). LSG is an effective bariatric operation for morbid obesity and obesity-related comorbidities (3). Since 2013, LSG has become the most common bariatric operation performed worldwide, overtaking the Roux-en-Y gastric bypass (RYGB) and essentially replacing the laparoscopic adjustable gastric band (4). LSG maintains anatomy and physiology of the gastrointestinal tract without the addition of foreign devices or materials (5). Despite its benefits in the treatment of morbid obesity and obesity-related comorbidities, the growing popularity of this procedure has introduced a new set of challenges to the surgical community. Complications from this procedure include the development of gastrointestinal leaks, esophageal dysphagia, and most commonly gastroesophageal reflux disease (GERD). In fact, 8.6–18.4% of patients develop GERD following sleeve gastrectomy for which the etiology is not entirely clear (6-8). Treatment options for GERD in LSG patients include diet, lifestyle modifications and anti-reflux medications such as proton pump inhibitors; however, when those therapies fail, there are limited options for patients given the altered stomach anatomy (9). The purpose of this review article is to discuss the surgical options for LSG patients with medically refractory GERD, the indications for each option, as well as its effectiveness.

Why GERD affects sleeve gastrectomy patients

For patients undergoing LSG, there are several mechanisms that can potentially contribute to worsening GERD. First, there is an increased incidence of sliding hiatal hernias in these patients post-operatively. The tube-like formation of the sleeve gastrectomy has a higher incidence of sliding above the diaphragm, which could affect the mechanics of the lower esophageal sphincter (LES). This is likely due to the absence of a fundus and lateral attachments of the short gastric vessels that are taken during the sleeve gastrectomy procedure. Second, the small stomach creates more intra-gastric pressure from the pylorus. In many cases, the creation of a tube-like stomach drives intragastric pressure proximally toward the LES, resulting in GERD (10). These potential contributors to post-sleeve gastrectomy GERD are illustrated in Figure 1.

Figure 1 Potential mechanisms for gastroesophageal reflux disease in post-operative laparoscopic sleeve gastrectomy patients.

The structural changes to the stomach are characterized by reduced size and modified anatomy, which can potentially disrupt the angle of His and the LES, enabling stomach contents to reflux into the esophagus (11,12). In Figure 2, we see the myoarchitecture of the LES and how this can be altered as a result of the procedure. The LES consists of the distal esophageal circular muscle which crosses at the angle of His to form sling fibers. When the LSG is created, the sling fibers can be disrupted which can lead to weakness of the LES (13). In the right patient with increased intragastric pressure or a sliding hiatal hernia, these factors likely play a role in why so many patients develop GERD following LSG.

Figure 2 Myoarchitecture of the lower esophageal sphincter (13). Permission file is not needed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).

Incidence and impact of GERD in post-LSG patients

In a study by Genco et al., LSG had a profound impact on GERD symptoms at 5 years postoperatively. The number of patients reporting GERD symptoms postoperatively compared to preoperatively doubled and the rate of Grade C/D esophagitis in these patients increased from 3.6% to 20.9%. Concerningly, none of these patients had Barrett’s esophagus (BE) preoperatively and 17.2% of patients developed BE at 5 years (14). A meta-analysis of studies with 7 or more years of outcomes for sleeve gastrectomy showed a dramatic rise in the revision rate of patients with LSG. Five percent of patients following LSG are revised due to GERD (15).

Symptoms of GERD following LSG extend beyond mild discomfort, exerting a discernible influence on the overall quality of life. In a study conducted by Balla et al. [2019], GERD-health related quality of life (HRQL) scores were obtained in 100 patients before and after LSG. The results indicated that 21% of patients experienced worsened GERD-HRQL scores and 10% developed de novo GERD, underscoring the impact of post-LSG GERD on patients’ overall quality of life (16). While medical therapy remains an essential component of GERD management, some patients develop symptoms refractory to these medications despite high doses. Some have postulated that reflux episodes occur more frequently in the postprandial state following sleeve gastrectomy and is made up of chiefly nonacidic ingested food. This may contribute to the lack of efficacy of proton pump inhibitor therapy in the management of GERD in these patients (17). When lifestyle modifications and medical therapy fail, surgery becomes the only option for symptom relief in these patients.

Surgical options for GERD in LSG patients

We recommend a complete esophageal workup for patients who develop medically refractory GERD symptoms. This includes an esophagogastroduodenoscopy (EGD), pH testing off medications, manometry, and a solid and liquid esophagram. In our practice, we can forego pH testing in the presence of Grade C/D esophagitis or BE on endoscopy. Once GERD is established in these patients, the workup will allow the surgeon to tailor the best surgical option for each patient. There are two surgical options for these patients: magnetic sphincter augmentation (MSA) and a subtotal gastrectomy with Roux-en-Y (SGRY) reconstruction. Due to the absence of a fundus, as a result of the prior LSG, a fundoplication is not an option in these patients.

MSA

This minimally invasive procedure involves the laparoscopic placement of a flexible band comprised of interconnected magnetic beads along a titanium wire, securely encircling the gastroesophageal (GE) junction (Figure 3). This dynamic band mechanism opens in response to swallowing, effectively preventing the backflow of stomach acid into the esophagus by sealing tightly when at rest. MSA demonstrates efficacy in alleviating GERD symptoms by reinforcing the LES (18). It is essential that the patient has good esophageal motility, allowing the esophageal muscles to generate sufficient pressure to open the magnetic beads upon swallowing. This is why manometry and solid phase esophagram are helpful in the preoperative workup.

Figure 3 Magnetic sphincter augmentation in patient with laparoscopic sleeve gastrectomy.

SGRY reconstruction

SGRY, the most common surgical intervention for post-LSG reflux, involves laparoscopic excision of a segment of the stomach and the establishment of a novel digestive pathway to circumvent the removed gastric portion (19). This new pathway is created by dividing the jejunum and affixing it to the residual upper stomach, forming the “Roux limb”. The Roux limb is subsequently connected to the biliopancreatic limb of the jejunum, adopting a Y-shaped configuration. This is very similar to a gastric bypass with Roux-en-Y reconstruction; however, when the procedure is not done for weight loss, we do not want to create the same amount of vitamin and mineral deficiencies. As a result, we make the limb lengths less than 200 cm total to reduce the GERD, as well as prevent bile reflux (20). Notably, for patients with a prior sleeve gastrectomy, the focus of this procedure is on the creation of this new connection, given their pre-existing stomach reduction. Roux-en-Y reconstruction introduces a limb lengthening effect, which contributes to a reduction in stomach acid exposure. It also facilitates expeditious gastric emptying by bypassing a portion of the duodenum, thereby diminishing the risk of gastric contents regurgitating into the esophagus.

Technique in brief

MSA

The MSA procedure entails several key steps. Dissection begins along the gastrohepatic ligament to expose the right crus, followed by circumferential dissection around the hiatus for full exposure. Any potential hiatal hernia is reduced during the full mediastinal dissection. Great care is taken during the mediastinal dissection to preserve the Vagus nerves. The hiatus is then closed using permanent sutures to achieve a secure closure around the esophagus. The posterior Vagus nerve is isolated, and a window is created between the posterior Vagus and the esophagus at the LES. An MSA sizer device is inserted to ensure accurate measurement, followed by the secure insertion and fixation of the device and suture removal.

SGRY reconstruction

Dissection begins by lifting the omentum above the colon and making a slit for the Roux limb, ensuring a tension-free connection to the gastric pouch. The Ligament of Treitz is identified and the biliopancreatic limb is measured to approximately 50 cm, at which point the small intestine is divided by staples and the mesentery is separated using cautery. The Roux limb is then measured to 50–100 cm depending on the length needed for the gastrojejunostomy to be constructed without tension. The jejunojejunostomy is constructed using a side-to-side stapled anastomosis. The gastric portion begins with isolation of the left gastric pedicle, followed by stapling across the lesser curve vessels. Additional staples are then added across the stomach to complete the formation of the gastric pouch. The Roux limb is brought up, enterotomies are created in both the stomach and the small bowel, and a 3-cm anastomosis is secured with staples. The common enterotomy is closed in two layers. All mesenteric defects are closed with nonabsorbable suture prior to skin closure.

Comparative analysis

Patient selection

Patient selection is crucial in determining the appropriate procedure. MSA is often recommended for patients with moderate GERD and who have hiatal hernias less than 3 cm and good esophageal motility (12). SGRY is recommended for patients with severe GERD and moderate to poor esophageal motility (21). A 2023 study described an algorithm for treating post-bariatric patients with reflux and concluded that MSA is not the first-line treatment for LSG GERD patients but does represent treatment for a certain subset (22). The algorithm states that if the patient has a body mass index greater than 35 or abnormal sleeve morphology or an esophageal diameter ≥3 cm, conversion to SGRY or RYGB is recommended. Whereas, if the patient has a body mass index less than 35, normal sleeve morphology, and an esophageal diameter <3 cm, MSA can be further considered pending evaluation of hiatal hernia presence. Additional guidelines include:

• Manometry guidelines:
  • Ensure the pressure of the sleeve is below 25 mmHg;
  • High pressure in the sleeve may lead to device opening and reflux.
• Endoscopy guidelines:
  • Perform retroflexion in the distal stomach;
  • Ensure the endoscope sits loosely at the incisura;
  • Tight endoscope placement may signal a need for conversion to SGRY or RYGB.

Nonetheless, this study concluded that despite the guidelines, certain patients might favor MSA over SGRY because of its reversibility and the fact that it does not introduce additional disruption to the foregut anatomy.

Efficacy

Current literature suggests that MSA provides significant improvement in GERD symptoms, reducing acid reflux, and regurgitation. In a study conducted by Khaitan et al. [2023] on post-sleeve gastrectomy patients treated with MSA, noteworthy outcomes were observed: 80.8% of patients experienced a significant reduction of at least 50% in GERD-HRQL scores (P=0.001), 95.8% demonstrated a >50% reduction in daily proton pump inhibitor usage, 53.8% exhibited improvements in esophagitis, and 61.5% achieved elimination of regurgitation (N=30) (23). A comprehensive systematic review encompassing 35 patients also revealed significant improvements in GERD-HRQL scores after MSA among the 33 individuals with a history of prior bariatric surgery (sleeve gastrectomy =29, RYGB =4) (P=0.005). However, it also noted that 20% encountered recurrent GERD, 14.3% reported persistent dysphagia, and 5.7% necessitated device removal (24). A 2022 study reported similar findings of 36% of patients requiring GERD medications frequently despite MSA, 41% requiring medication rarely, and 23% reaching proton pump inhibitor liberation. This study also found that 14% of patients were “dissatisfied” with MSA, for reasons of persistent reflux symptoms requiring proton pump inhibitor therapy and dysphagia (N=22) (25).

In contrast, in SGRY procedures, Strauss et al. [2023] found that the majority of patients will experience improvements in GERD symptoms after conversion to RYGB, 80.2% reporting improvements in global symptoms and 19.4% no longer requiring proton pump inhibitors. However, in this study 80.5% of patients had difficulty liberating from proton pump inhibitors despite revision and a mean weight loss of 11.1 kg (n=70). One noted possible explanation for this subset may be non-erosive reflux disease, marked by heightened sensitivity and increased vigilance in the esophagus, but further research is warranted (26).

Long-term outcomes

While long-term outcomes for MSA and SGRY for refractory GERD are limited, meaningful comparisons can be cautiously made by considering the outcomes from a broader population. This is based on the findings of a study on MSA in patients with prior gastric surgery, which demonstrated equivalent outcomes when compared to patients without prior gastric surgery (27). When evaluating the general population, the 6-to-12-year outcomes indicate that MSA offers lasting symptom relief, yielding over a 50% reduction in GERD-HRQL scores. This long-term study further confirms the absence of erosions or migrations within the studied population, with the overall incidence of erosion for MSA being less than 0.5% (28). An additional study evaluating the safety of the first 1,000 patients treated with MSA demonstrated one case of device erosion, resulting in a total device erosion rate of 0.1% (29). While these both point to favorable outcomes, it’s worth noting that 82% of MSA device explants occur between 12–24 months, with reoccurring heartburn and dysphagia being the primary cause (28,30).

For SGRY, anastomotic marginal ulcer is a late complication associated with primary surgery with an estimated frequency of 3%. One study on conversion of LSG to RYGB for the indication of weight loss failure and severe GERD, showed that of the nine GERD patients, one developed a gastrointestinal anastomotic ulcer requiring surgical intervention 1 year after revision (21). While RYGB for GERD within the general population shows improvements or the absence of GERD symptoms at a mean follow-up of 18 months, 12% of patients experienced complications including leak, pulmonary emboli, internal roux intestinal limb hernia, and gastrojejunal strictures (31).

In conclusion, while long-term data for MSA and SGRY in managing refractory GERD is limited, the comprehensive findings from studies on MSA and SGRY provide valuable insights into the potential outcomes for these surgical approaches in LSG patients. However, it is evident that further research is essential to fully understand the long-term effectiveness, potential complications, and suitability of these procedures for specific LSG patients. This ongoing investigation will continue to refine the understanding of how best to manage refractory GERD in patients, balancing symptom relief with potential surgical complications and the preservation of overall health and quality of life.

Safety

Safety considerations are vital when comparing MSA and SGRY. MSA is minimally invasive and generally associated with fewer complications. According to a study by Grover et al. [2023], select patients with a history of sleeve gastrectomy can safely undergo MSA and achieve improved control of reflux and discontinuation of proton pump inhibitors. This study found 21 total adverse events (19 were anticipated), 2 serious adverse events, 2 device explantations (1 requiring conversion to SGRY), 2 readmissions, and 0 deaths, device migrations, and erosions over a 12-month postoperative period. The most common adverse event was dysphagia at 16.7% and epigastric pain/bloating at 10% (N=15) (22). In a separate investigation, 70% of patients experienced no postoperative complications, with all procedures being conducted laparoscopically and no instances requiring conversion to open surgery. Additionally, no adverse events, such as MSA device erosion or device-related mortalities, were recorded (N=22) (25).

Conversely, a 2023 study investigating SGRY after LSG, reported an overall postoperative complication rate of 24.7%, with 11.3% being grade I complications, 6.19% grade II, 5.15% grade III, and 2.06% grade IV (N=97). Additionally, 16.5% of patients were readmitted within 30 days of their procedure date. Reasons for readmission consisted of pain control, ileus, bowel obstruction, postoperative fluid collection, nausea/vomiting, and oral intolerance. Following 30 days, 8.2% of patients developed ulceration at the gastrojejunostomy site (26). Poghosyan et al. [2016] supported that conversion of LSG to RYGB allows improvement in secondary weight loss and GERD, but at the cost of high morbidity (N=34). This study reported that 32 procedures were done laparoscopically, with one conversion to laparotomy and one to laparotomy straightway. There was no postoperative mortality (<90 days), however, 11.7% of patients developed major adverse events requiring reoperation within the 90 days following surgery. These events consisted of gastrojejunostomy leak, intestinal wound, strangulated hernia at trocar port, and exploratory laparoscopy for abdominal discomfort. Late morbidity (>90 days) was experienced in 8.8% of patients with perforated anastomotic ulcer, strangulated hernia at trocar port, and exploratory laparoscopy for abdominal discomfort (21). In addition to complication rates and adverse effects, operation time is an important factor to consider when evaluating safety. The mean operation length for MSA was 58.1 minutes, while the mean length for SGRY is notably longer, ranging from 145–155 minutes (19,23,26). In summary, both procedures are generally considered safe; however, it’s important for patients and physicians to recognize the higher incidence of postoperative complications in SGRY, the common adverse effects that MSA may entail, and the operative time differences for each procedure.

Conclusions

In conclusion, this review navigates the landscape of managing post-LSG GERD, shedding light on the surgical options—MSA and SGRY. Patient selection emerges as a critical consideration, with MSA offering a minimally invasive approach suitable for moderate GERD, and SGRY presenting a comprehensive option with notable improvements in global symptoms for patients with severe GERD, esophageal dysmotility, and increased body mass index. MSA exhibits a safety advantage, boasting fewer complications and a shorter operative time, but it can result in recurrent GERD symptoms, persistent dysphagia, as well as device removal. On the other hand, SGRY, while involving a longer procedure time, showcases meaningful outcomes with improved GERD symptoms and reduced reliance on proton pump inhibitors. As we navigate this evolving field, the call for ongoing research remains imperative. Further research, including long-term outcomes, cost-effectiveness, and direct comparisons between these two approaches, is needed to guide clinical decision-making, optimize patient care, and provide a comprehensive understanding of their relative benefits and drawbacks.

Acknowledgments

Funding: None.

Footnote

Peer Review File: Available at https://ales.amegroups.com/article/view/10.21037/ales-23-73/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://ales.amegroups.com/article/view/10.21037/ales-23-73/coif). The authors have no conflicts of interest to declare.

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References

1. Panuganti KK, Nguyen M, Kshirsagar RK. Obesity. 2023 Aug 8. In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available online: https://www.ncbi.nlm.nih.gov/books/NBK459357/
2. Chao GF, Yang J, Thumma J, et al. Volume-outcome relationships for Roux-en-Y gastric bypass patients in the sleeve gastrectomy era. Surg Endosc 2022;36:3884-92. [Crossref] [PubMed]
3. Golzarand M, Toolabi K, Farid R. The bariatric surgery and weight losing: a meta-analysis in the long- and very long-term effects of laparoscopic adjustable gastric banding, laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy on weight loss in adults. Surg Endosc 2017;31:4331-45. [Crossref] [PubMed]
4. Khorgami Z, Shoar S, Andalib A, et al. Trends in utilization of bariatric surgery, 2010-2014: sleeve gastrectomy dominates. Surg Obes Relat Dis 2017;13:774-8. [Crossref] [PubMed]
5. Shi X, Karmali S, Sharma AM, et al. A review of laparoscopic sleeve gastrectomy for morbid obesity. Obes Surg 2010;20:1171-7. [Crossref] [PubMed]
6. DuPree CE, Blair K, Steele SR, et al. Laparoscopic sleeve gastrectomy in patients with preexisting gastroesophageal reflux disease: a national analysis. JAMA Surg 2014;149:328-34. [Crossref] [PubMed]
7. Neagoe R, Muresan M, Timofte D, et al. Long-term outcomes of laparoscopic sleeve gastrectomy - a single-center prospective observational study. Wideochir Inne Tech Maloinwazyjne 2019;14:242-8. [Crossref] [PubMed]
8. Seeras K, Sankararaman S, Lopez PP. Sleeve Gastrectomy. 2024.
9. Slater BJ, Dirks RC, McKinley SK, et al. SAGES guidelines for the surgical treatment of gastroesophageal reflux (GERD). Surg Endosc 2021;35:4903-17. [Crossref] [PubMed]
10. Savarino E, Marabotto E, Savarino V. Effects of bariatric surgery on the esophagus. Curr Opin Gastroenterol 2018;34:243-8. [Crossref] [PubMed]
11. Stenard F, Iannelli A. Laparoscopic sleeve gastrectomy and gastroesophageal reflux. World J Gastroenterol 2015;21:10348-57. [Crossref] [PubMed]
12. Reddy NC, Sujka J, DuCoin C. Magnetic Sphincter Augmentation Algorithm for Post-bariatric Surgery Gastroesophageal Reflux Disease Patients. Obes Surg 2022;32:3185-7. [Crossref] [PubMed]
13. Zifan A, Kumar D, Cheng LK, et al. Three-Dimensional Myoarchitecture of the Lower Esophageal Sphincter and Esophageal Hiatus Using Optical Sectioning Microscopy. Sci Rep 2017;7:13188. [Crossref] [PubMed]
14. Genco A, Soricelli E, Casella G, et al. Gastroesophageal reflux disease and Barrett's esophagus after laparoscopic sleeve gastrectomy: a possible, underestimated long-term complication. Surg Obes Relat Dis 2017;13:568-74. [Crossref] [PubMed]
15. Clapp B, Wynn M, Martyn C, et al. Long term (7 or more years) outcomes of the sleeve gastrectomy: a meta-analysis. Surg Obes Relat Dis 2018;14:741-7. [Crossref] [PubMed]
16. Balla A, Quaresima S, Palmieri L, et al. Effects of Laparoscopic Sleeve Gastrectomy on Quality of Life Related to Gastroesophageal Reflux Disease. J Laparoendosc Adv Surg Tech A 2019;29:1532-8. [Crossref] [PubMed]
17. Del Genio G, Tolone S, Limongelli P, et al. Sleeve gastrectomy and development of "de novo" gastroesophageal reflux. Obes Surg 2014;24:71-7. [Crossref] [PubMed]
18. Bonavina L, Saino GI, Bona D, et al. Magnetic augmentation of the lower esophageal sphincter: results of a feasibility clinical trial. J Gastrointest Surg 2008;12:2133-40. [Crossref] [PubMed]
19. Dang JT, Vaughan T, Mocanu V, et al. Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass: Indications, Prevalence, and Safety. Obes Surg 2023;33:1486-93. [Crossref] [PubMed]
20. Genco A, Castagneto-Gissey L, Gualtieri L, et al. GORD and Barrett's oesophagus after bariatric procedures: multicentre prospective study. Br J Surg 2021;108:1498-505. [Crossref] [PubMed]
21. Poghosyan T, Lazzati A, Moszkowicz D, et al. Conversion of sleeve gastrectomy to Roux-en-Y gastric bypass: an audit of 34 patients. Surg Obes Relat Dis 2016;12:1646-51. [Crossref] [PubMed]
22. Grover K, Khaitan L. Magnetic sphincter augmentation as treatment of gastroesophageal reflux disease after sleeve gastrectomy. Dis Esophagus 2023;36:doad030. [Crossref] [PubMed]
23. Khaitan L, Hill M, Michel M, et al. Feasibility and Efficacy of Magnetic Sphincter Augmentation for the Management of Gastroesophageal Reflux Disease Post-Sleeve Gastrectomy for Obesity. Obes Surg 2023;33:387-96. [Crossref] [PubMed]
24. Riva CG, Asti E, Lazzari V, et al. Magnetic Sphincter Augmentation After Gastric Surgery. JSLS 2019;23:e2019.00035.
25. Patel SH, Smith B, Polak R, et al. Laparoscopic magnetic sphincter augmentation device placement for patients with medically-refractory gastroesophageal reflux after sleeve gastrectomy. Surg Endosc 2022;36:8255-60. [Crossref] [PubMed]
26. Strauss AL, Triggs JR, Tewksbury CM, et al. Conversion to Roux-En-Y Gastric Bypass: a successful means of mitigating reflux after laparoscopic sleeve gastrectomy. Surg Endosc 2023;37:5374-9. [Crossref] [PubMed]
27. Leeds SG, Ngov A, O, Ogola G, et al. Safety of magnetic sphincter augmentation in patients with prior bariatric and anti-reflux surgery. Surg Endosc 2021;35:5322-7. [Crossref] [PubMed]
28. Ferrari D, Asti E, Lazzari V, Siboni S, et al. Six to 12-year outcomes of magnetic sphincter augmentation for gastroesophageal reflux disease. Sci Rep 2020;10:13753. [Crossref] [PubMed]
29. Lipham JC, Taiganides PA, Louie BE, et al. Safety analysis of first 1000 patients treated with magnetic sphincter augmentation for gastroesophageal reflux disease. Dis Esophagus 2015;28:305-11. [Crossref] [PubMed]
30. Asti E, Siboni S, Lazzari V, et al. Removal of the Magnetic Sphincter Augmentation Device: Surgical Technique and Results of a Single-center Cohort Study. Ann Surg 2017;265:941-5. [Crossref] [PubMed]
31. Perry Y, Courcoulas AP, Fernando HC, et al. Laparoscopic Roux-en-Y gastric bypass for recalcitrant gastroesophageal reflux disease in morbidly obese patients. JSLS 2004;8:19-23. [PubMed]