Short term safety of magnetic sphincter augmentation vs minimally invasive fundoplication: an ACS-NSQIP analysis

Purpose Magnetic Sphincter Augmentation (MSA) is an FDA-approved anti-reflux procedure with comparable outcomes to fundoplication. However, most data regarding its use are limited to single or small multicenter studies which may limit the generalizability of its efficacy. The purpose of this study is to evaluate the outcomes of patients undergoing MSA vs fundoplication in a national database. Materials and Methods The 2017–2020 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) Registry was utilized to evaluate patients undergoing MSA or fundoplication. Patients requiring Collis gastroplasty, paraesophageal hernia repair, and emergency cases, were excluded. Patient outcomes included overall complication rates, readmissions, reoperations, and mortality. Results A total of 7,882 patients underwent MSA (n = 597) or fundoplication (n = 7285). MSA patients were younger (51 vs 57, p < 0.001), and more often male (49.6 vs 34.3%, p < 0.001). While patients undergoing MSA experienced similar rates of reoperation (1.0 vs 2.0%, p = 0.095), they experienced fewer readmissions (2.2 vs 4.7%, p = 0.005), complications (0.6 vs 4.0%, p < 0.001), shorter mean (SD) hospital length of stay(days) (0.4 ± 4.3 vs 1.8 ± 4.6, p < 0.001) and operative time(min) (80.8 ± 36.1 vs 118.7 ± 63.7, p < 0.001). Mortality was similar between groups (0 vs 0.3%, p = 0.175). On multivariable analysis, MSA was independently associated with reduced postoperative complications (OR 0.23, CI 0.08 to 0.61, p = 0.002), readmissions (OR 0.53, CI 0.30 to 0.94, p = 0.02), operative time (RC − 36.56, CI − 41.62 to − 31.49. p < 0.001) and length of stay (RC − 1.22, CI − 1.61 to − 0.84 p < 0.001). Conclusion In this national database study, compared to fundoplication MSA was associated with reduced postoperative complications, fewer readmissions, and shorter operative time and hospital length of stay. While randomized trials are lacking between MSA and fundoplication, both institutional and national database studies continue to support the use of MSA as a safe anti-reflux operation. Supplementary Information The online version contains supplementary material available at 10.1007/s00464-024-10672-7.

Gastroesophageal disease (GERD) is one of the most common chronic gastrointestinal disorders with an estimated national prevalence of 20% [1].The pathophysiology of GERD is multifactorial, but there is consensus that the disruption or displacement of the lower esophageal sphincter results in retrograde flow of gastric contents into the esophagus [2].Patients' quality of life if often affected by GERD and its associated regurgitation, heartburn, cough, chest pain, dysphagia, and asthma, one or more of which may be present in up to 60% of patients [3].
The prevalence of GERD is likely underreported due to frequent self-medication via over-the-counter medications [4].Nevertheless, initial management relies on lifestyle modifications and pharmacological treatment with acid suppression medications [4].While satisfaction rates on medical management are reported to be around 50%, patients with refractory symptoms, medical noncompliance, presence of hiatal hernia, or those who do not desire to take lifelong medications may be referred for surgical therapy [5].
The most common surgical approach to GERD is a fundoplication.However, long term side effects such as gas and bloating are reported to be around 30% [6].An alternative surgical modality for GERD is magnetic sphincter augmentation (MSA), which has gained adoption over the past 15 years.Short-and long-term studies have demonstrated equivalent efficacy between fundoplication and MSA in GERD outcomes while maintaining a limited side effect profile.This purpose of this study is to evaluate nationwide outcomes of MSA compared to fundoplication.

Data source
The American College of Surgeons National Surgical Quality Improvement Database (NSQIP) is comprised of data from over 600 participating hospitals.Data from NSQIP 2017-2020 was included in this study.Institutional Review Board approval was not required for this study.

Study population
The study population consisted of all patients undergoing MSA and laparoscopic fundoplication between 2017 and 2020 based on Common Procedural Codes 43284 and 43280, respectively.All emergency cases and patients undergoing concomitant paraesophageal hernia repair or Collis gastroplasty were excluded, Fig. 1.The overall complication rate consisted of all postoperative complications including: superficial surgical site infection, deep incisional site infection, organ space infection, wound disruption, pneumonia, unplanned intubation, pulmonary embolism, ventilator over 48 h, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke, cardiac arrest requiring cardiopulmonary resuscitation, bleeding requiring transfusion, deep vein thrombosis, sepsis, or septic shock.Causes of readmission were evaluated using ICD-10 codes which described postoperative complications including gastroesophageal reflux, dysphagia, nausea or vomiting, postoperative pain, ileus or obstruction, seroma or hematoma, gastric motility issues, and diaphragmatic hernia, Supplementary Table 1.Patient demographics, intraoperative details, and 30-day outcome data were reviewed.

Statistical Analysis
Categorical variables were evaluated with Chi-squared and Fisher's exact tests.Continuous variables were evaluated using Mann-Whitney U for nonparametric data, and Student's T test for parametric data.Significant univariable outcomes on comparative analyses were evaluated using binary logistic regression.Multiple logistic regression with forward stepwise variable selection was used to construct a predictive model.Independent variables with

Multivariable regression outcomes
On multivariable logistic regression, MSA patients had fewer cases of pneumonia and urinary tract infections although these outcomes did not reach statistical significance.However, MSA patients did have a significantly lower rate of readmission (OR 0.534, p = 0.029) and overall complications (OR 0.228, p = 0.004), Table 4. Multivariable linear regression demonstrated that MSA was associated with significantly reduced length of hospitalization (RC = − 1.222, p < 0.001), and reduced operative time (RC = − 36.558,p < 0.001), Table 5.

Discussion
Gastroesophageal reflux disease is a common disease that affects at least one out of every five Americans.Despite medical optimization, nearly half of all patients experience persistent GERD symptoms [1,4].Traditional surgical therapy involves a fundoplication, which can have frequent and bothersome side effects and complications.Alternatively, The only contraindication to the use of MSA is metal allergy.The Food and Drug Administration additionally lists multiple precautionary conditions such as Age < 21, body mass index (BMI) > 35, pregnancy status, and various esophageal functional, and structural comorbidities [6].In the author's institution, we maintain avoiding device implantation in patients under 21 years of age, pregnancy, malignancy, esophageal varices, and those with concurrent electrical implants.Aside from these is used in broadly including in patients with precautionary conditions with a preoperative discussion reviewing the risks of failure and need for reintervention or explantation.Several studies have demonstrated the safety of MSA in esophageal dysmotility, advanced esophagitis, Barrett's esophagus, and BMI > 35 [7][8][9].In this study, despite differing baseline demographics and co-morbidities, there were few postoperative differences noted between groups on comparative analysis.MSA patients experienced reduced operative time and length of stay which is consistent with other contemporary studies.In a prospective, multi-institutional study, Reynolds et al. reported a mean MSA operative time of 60 min and mean length of stay of 11 h [10].Other studies have demonstrated similar operative times in a range 40-66 min in patients undergoing MSA, compared 76-90 min in patients undergoing Nissen fundoplication [11][12][13][14].Furthermore, while early trials on MSA monitored patients overnight, same day discharge has been shown to be safe [13,14] Lastly, a recent meta-analysis showed MSA was associated with reduced operative time and length of stay compared to fundoplication [15].These findings likely result from the elimination of significant esophago-gastric mobilization and fixation required during fundoplication.
Rates of postoperative complications were slightly different between the MSA and fundoplication patients Those undergoing fundoplication experienced greater rates of urinary tract infections, pneumonia, readmissions, and overall complications.In a propensity matched study of 100 patients undergoing MSA vs Nissen fundoplication, Reynolds et al. demonstrated no complications at 1 year, while 2 major complications (dehydration and esophageal obstruction) and 2 minor complications (postoperative seizure and urinary tract infection) were noted in the Nissen cohort [13].In a study examining the first 1000 MSA cases utilizing the Manufacturer and User Facility Device Experience Database, Lipham et al. reported readmission rates of 1.3% over a 90-day postoperative period.0.8.When comparing similar readmission criteria, the overall rate of readmission for this study is 0.8%; however, this is not an equal comparison as the NSQIP database captures 30-day complications compared to 90-day complication in the Manufacturer's database [16].Prolonged operative time has been shown to be associated with increased perioperative complications.In an ACS-NSQIP analysis, Jackson et al. showed patients undergoing minimally invasive Nissen fundoplication demonstrated increasing odds of complications with increasing operative time (p < 0.001) [17].Similarly in a recent systematic review, Chen et al. showed increasing complications with increasing operative time across multiple surgical specialties [15].In our study, operative time was significantly longer in patients undergoing laparoscopic fundoplication and this may, in part, explain the findings of increased overall complication rates seen in this study.
The limitations of this study are inherent to the ACS-NSQIP database.First, data are available for only the first 30 days postoperatively.While this is valuable in the assessment of safety, studies have demonstrated the development of long-term complications such as dysphagia, and MSA device erosion requiring intervention or explantation.Second, the database is unable to distinguish between partial and Nissen fundoplication.MSA is more comparable to a Nissen fundoplication given the circumferential positioning of the device.Additionally, different fundoplication techniques such as anterior or posterior wraps, or retention of the short gastric vessels, may skew outcome data.Finally, objective and subjective data on GERD outcomes is lacking such as esophagram, esophageal pH studies, histopathological data, and standardized patient GERD quality of life questionaries which would allow for an examination of efficacy outcomes of MSA vs fundoplication.

Conclusion
This is the first known large database evaluation of the shortterm outcomes of MSA compared to minimally invasive fundoplication.Most studies on MSA up to now utilize data from high-volume institutions; in contrast, NSQIP represents cases from more than 600 hospitals allowing for more generalizable data.This study demonstrates reduced operative time, hospital stay, readmission rates, and overall complications for patients undergoing MSA compared to fundoplication.While these data represent 30-day outcomes, MSA is a safe alternative to minimally invasive fundoplication.
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Table 1
Demographics and characteristics magnetic sphincter augmentation vs fundoplication Diabetes diabetes mellitus type 2, COPD chronic obstructive pulmonary disease, CHF congestive heart failure, ASA classification American Society of Anesthesiologists classification

Table 2
Perioperative outcomes magnetic sphincter augmentation vs fundoplication

Table 3
Causes of readmission magnetic sphincter augmentation vs fundoplication