A new manometric tool to evaluate the efficacy of laparoscopic anti-reflux surgery: first postoperative application of the Milan score

Introduction

High-resolution manometry (HRM) has a well-established role in the evaluation of patients with suspected gastroesophageal reflux disease (GERD), mainly providing measurement for a correct placement of the catheter for pH-impedance (MII-pH) and excluding major esophageal motility disorders. While the Lyon consensus 2.0 (1) defines definitive criteria for the diagnosis or exclusion of GERD according to endoscopic and MII-pH findings only, HRM provides adjunctive information on reflux physiology, identifying a hypotonic esophagogastric junction (EGJ), a hiatal hernia or an ineffective esophageal motility (IEM).

Recently, a new manometric tool, named Milan score (MS), has been proposed and validated in a prospective multicenter study among patients undergoing a thorough diagnostic work-up for suspected GERD, including catheter based MII-pH or wireless pH-test, HRM and upper endoscopy. The score integrates four HRM variables related to the pathophysiology of GERD, including: presence of IEM, EGJ morphology, EGJ contractile integral (EGJ-CI) and response to the straight leg raise (SLR) maneuver. The final score has been proven able to relate to a pathologic reflux monitoring test, providing a risk rate for GERD (2).

When a pathologic reflux is demonstrated, laparoscopic anti-reflux surgery (LARS) is a valid option for patients with severe GERD or unwilling to assume long-term medications, patients with hiatal hernia or with poor symptoms control or abnormal tests despite adequate medical therapy, which might benefit from a stepwise escalation in therapeutic options, i.e. patients with actionable GERD (1).

The goal of surgery is to restore anatomy and function of the EGJ, obtaining a proper intrabdominal length of the distal esophagus, repairing the hiatus and producing an adequate increase in competency of the EGJ (3). The most common options for LARS are total and partial fundoplication and magnetic sphincter augmentation (MSA).

Postoperatively, the efficacy of LARS should be evaluated over time both clinically, in terms of symptoms relief, and objectively, with an instrumental follow-up including endoscopy and pH-monitoring to investigate the integrity of post-surgical anatomy and function. Postoperative HRM has a role in patients with unsuccessful LARS, due to persistent or recurrent reflux symptoms or dysphagia, and may show various patterns demonstrating post-operative abnormalities (4).

The novel MS has never been validated in the post-surgical setting. While the gold standard to confirm an adequate acid reflux control after surgery is pH-monitoring, which can be poorly tolerated especially when catheter-based, and does not provide anatomical and functional description of the post-surgical EGJ, we hypothesized that HRM with the MS could be a useful tool in the evaluation of patients after LARS, being more informative than the pH-test in the description of the EGJ and more objective than clinical evaluation alone. The aim of this study is to test the efficacy of the score to assess the restoration of anti-reflux mechanisms in patients undergoing postoperative HRM and its relation to reflux symptoms, comparing manometric findings between different surgical techniques.

Methods

Study population

All patients referred to the esophageal function test laboratory of our tertiary care center for esophageal diseases at IRCCS Policlinico San Donato (Milan) for HRM after LARS between October 2020 and May 2023 were included in this retrospective study. Study population included both asymptomatic patients undergoing a routine follow-up and symptomatic patients undergoing evaluation for suspected recurrent GERD, operated in our or other centers. Exclusion criteria were: age under 18, anti-reflux surgery concomitant to Heller myotomy for achalasia or following bariatric surgery, absent or inadequate SLR maneuver during HRM and incomplete or missing clinical questionnaires. After the inclusion and exclusion process, all patients meeting these criteria were enrolled in the final sample size.

HRM evaluation

All HRM reports were screened to identify patients satisfying inclusion criteria and to collect manometric variables, as well as information about symptoms and use of antisecretory medications at that time. Patients’ medical records were reviewed to include demographic and operative data. Upper gastrointestinal (GI) endoscopy and esophageal swallow studies performed within 2 months prior or after manometry were also collected.

In our practice, at the time of function tests, patients undergo a thorough investigation of symptoms through the self-administration of validated questionnaires for GERD and dysphagia. Validated questionnaires for GERD included: GERD Questionnaire (GERD-Q), GERD Health Related Quality of Life (GERD-HRQL) and Reflux Symptom Index (RSI). The GERD-Q is divided to GERD-Q(A), focused on assessing GERD probability (abnormal when ≥8), and GERD-Q(B) for GERD impact on quality of life [abnormal when ≥3 (5,6)]; the GERD-HRQL has a main focus on heartburn, and is pathologic when ≥10 (7); the RSI evaluates mainly atypical symptoms and is abnormal when >13 (8-10). Functional Outcome Swallowing Score (FOSS) questionnaire was used to evaluate dysphagia, with a grading between 0 (asymptomatic) to 5 (absolute dysphagia) (11). A FOSS score ≥1, indicating the presence of any grade of dysphagia, was considered abnormal in this study.

HRM was performed by expert physicians with ManoView™ ESO v3.3 (Medtronic, Minneapolis, MN, USA), following the Chicago Classification 4.0 (CCv.4.0) standard protocol (12) after an overnight fast. In our practice, ten swallows of 5 mL room temperature water are performed in the upright position, followed by 5 swallows in the recumbent position. Multiple rapid swallows (MRS) are performed with five 2 mL swallows administered within a 3 seconds interval, and esophageal contraction reserve was present when the ratio between distal contractile integral (DCI) of MRS and mean DCI of ten single swallows was higher than 1. After the standard HRM protocol, the SLR maneuver was performed (13), asking the patient to raise one or both legs for at least five seconds in the recumbent position and without swallowing, with the operator being allowed to give help in case the patient was unable to elevate the legs alone. The maneuver was considered effective when an increase of at least 50% of the intrabdominal pressure (IAP) was reached. The SLR was abnormal when an increase of at least 11 mmHg of intraesophageal peak pressure compared to basal peak pressure was recorded, both measured 5 cm above the lower esophageal sphincter (LES) in a 5 seconds interval.

LES and EGJ were assessed evaluating LES basal pressure, total and intrabdominal LES length, EGJ morphology and EGJ-CI. EGJ morphology was defined by the relationship between LES and crural diaphragm (CD) into three types: type 1, superimposed LES and CD; type 2, LES-CD separation <3 cm; type 3, LES-CD separation ≥3 cm. EGJ-CI was calculated during the reference period using the DCI software tool with isobaric contour for gastric pressure +2 mmHg over the EGJ for three respiratory cycles (14).

Peristalsis vigor was defined categorizing each swallow as intact (DCI ≥450 mmHg*cm*s), weak (100≤ DCI <450) or failed (DCI<100). IEM was defined as >70% ineffective swallows or ≥50% failed swallows.

MS calculation

After the analysis of each HRM tracing, the MS was calculated evaluating EGJ type, EGJ-CI, presence of IEM and response to SLR, and assigning to each parameter a score, previously established through a statistical model. The sum of the points assigned to each variable provides the final MS. With regards to EGJ type, points assigned are 0, 24 or 46 for type 1, 2 or 3, respectively. The EGJ-CI is considered as a continuous variable, and the lower is its value, the higher is the corresponding score assigned. A total of 27 points are assigned when an IEM is diagnosed, while an abnormal SLR maneuver is worth 100 points. Figure 1 provides an example of MS calculation. A web calculator can be found at www.milanscore.com.

Figure 1 Example of MS calculation through its nomogram. IEM, ineffective esophageal motility; SLR, straight leg raise; EGJ-CI, esophagogastric junction contractile integral; EGJ, esophagogastric junction; MS, Milan score.

The final MS corresponds to a risk rate of a pathologic reflux monitoring test, defined as AET >6%. Different values of MS identify six different risk classes for pathologic GERD (Figure 2), with a score of 137 corresponding to a risk rate of 50%, thus being indicated as a cut-off to separate patients that are unlikely (MS <137) from those who are likely (MS ≥137) to have GERD.

Figure 2 Risk classes for GERD according to MS results. Image from www.milanscore.com. GERD, gastroesophageal reflux disease; RR, risk rate; MS, Milan score.

Statistical analysis

Patients were divided in groups and compared according to results of validated questionnaires and according to MS values. The discriminative performance of the MS to predict abnormal questionnaires for GERD in the study population was evaluated by calculating the area under the receiver operating characteristic (ROC) curve (AUC). A further sub-analysis was performed comparing the results of the most frequent surgical techniques. Continuous variables are presented as median and interquartile range (IQR) and are analysed with Mann-Whitney U-test for independent variables. Discreet variables are presented as values and percentages and are analysed with Fisher’s exact test. Statistical analysis was performed using IBM^® SPSS^® Statistics software Version 28. Statistical significance is set for a two-tailed P value <0.05.

Ethical considerations

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the institutional ethics board of I.R.C.C.S. Policlinico San Donato (No. HS-23-00139) and individual consent for this retrospective analysis was waived.

Results

A total of 160 patients were included in the study population [63% males, median age 53.5 years, median body mass index (BMI) 25.1 kg/m²], with a median follow-up time of 30 months. Figure 3 details the inclusion and exclusion process. Among these patients, about 85% underwent LARS in our institution, while the others were referred from other centers, and about 16% were included in this study during a follow-up after a redo operation for recurrent GERD or hiatal hernia. This population included patients who underwent LARS in a period of time ranging from January 1999 to October 2022. Most frequent surgical techniques were MSA with LINX^® device (53.8%) and Toupet fundoplication (28.7%). More than 40% of patients had at least a pathologic result of the questionnaires administered to evaluate GERD symptoms, while about 30% of patients had any abnormality at follow-up endoscopy. About 43% of patients had a MS ≥137, corresponding to a risk of GERD ≥50%. Table 1 shows demographic characteristics and results of clinical and instrumental follow-up of the overall population.

Figure 3 Flowchart showing the inclusion process for the study population. HRM, high-resolution manometry; LARS, laparoscopic anti-reflux surgery.

Patients were compared according to the results of questionnaires. We found that 28.1% had a positive GERD-Q(A), 32.5% a positive GERD-HRQL and 14.3% had an abnormal RSI. In all cases, patients with abnormal results had a significantly longer follow-up time, while no other differences were found in terms of demographic or surgical characteristics. Patients with abnormal questionnaires showed worse symptoms and abnormal results to other questionnaires, as well as significantly higher MS results and corresponding higher risk for GERD. Regarding HRM characteristics, all pathologic questionnaires were related to a higher rate of positive SLR maneuver, while the presence of hiatal hernia, a higher EGJ type and a shorter intrabdominal LES were significantly more prevalent in pathologic GERD-Q(A) and GERD-HRQL. Accordingly, the rate of a pathologic MS was higher in all the groups of pathologic questionnaires (Table 2).

When evaluating the distribution of abnormal questionnaires among the risk classes for GERD identified by the MS, we found an increasing rate of pathologic questionnaires for higher risk classes, reaching a 100% positivity for each questionnaire in the “extremely likely” class. Overall, more than 75% of patients with a MS ≥137 had a pathologic questionnaire (Figure 4).

Figure 4 Distribution of pathologic questionnaires over risk classes for GERD according to the MS. MS, Milan score; GERD-Q, gastroesophageal reflux disease questionnaire; HRQL, health related quality of life; RSI, Reflux Symptom Index; GERD, gastroesophageal reflux disease.

When the population was divided according to MS positivity, we found a relation between a MS ≥137 and abnormal findings at follow-up endoscopy, such as the presence of a recurrent hiatal hernia (P=0.046), esophagitis (P=0.007) or Barrett esophagus (P=0.007), as shown in Table 3.

The ROC analysis testing the ability of the MS in predicting an abnormal questionnaire showed an AUC of 0.728 [95% confidence interval (CI): 0.638–0.819] for GERD-Q(A), 0.765 (95% CI: 0.679–0.851) for GERD-HRQL, 0.696 (95% CI: 0.581–0.811) for RSI and 0.746 (95% CI: 0.666–0.827) in patients with any positivity at questionnaires. Figure 5 shows the ROC curves and the corresponding optimal thresholds for the MS with their values of sensitivity and specificity.

Figure 5 Area under the ROC curve of the MS tested for the positivity of each of the validated questionnaires and for any abnormal questionnaire, with optimal thresholds and corresponding sensitivity and specificity. CI, confidence interval; GERD-Q, gastroesophageal reflux disease questionnaire; HRQL, health related quality of life; RSI, Reflux Symptom Index; ROC, receiver operating characteristic; MS, Milan score.

In a second analysis we compared the two groups with larger sample size according to the surgical technique, MSA (86 patients) and Toupet fundoplication (46 patients), as shown in Table 4. We found no difference in terms of reflux symptoms and results of validated questionnaires, while patients in the MSA group had more often a positive FOSS (37.6% vs. 18.6%, P=0.043), indicating a certain grade of dysphagia. Manometry findings were similar between the groups in terms of EGJ type, hiatal hernia, esophageal motility and results of the MS, while patients in the MSA group showed significantly higher LES basal pressure (P=0.002), IRP (P=0.001), MRS-DCI (P=0.004) and EGJ-CI (P<0.001).

Discussion

In this study we aimed to apply a novel manometric score validated for GERD risk stratification as a follow-up tool to evaluate the efficacy of LARS. We found that an abnormal postoperative MS is related to positive results of questionnaires for reflux symptoms evaluation, proving that the score is able to discriminate patients with persistent or recurrent symptoms.

Postoperative HRM has a well-established role in the evaluation of EGJ anatomy and function after LARS. A successful fundoplication appears on the manometric plot as a single high-pressure zone (HPZ) corresponding to post-surgical EGJ, with increased pressure metrics compared to surgery-naïve patients, including higher LES basal pressure EGJ-CI and IRP, maintaining an appropriate deglutitive relaxation (15,16). The visualization of a dual HPZ indicates an altered post-surgical anatomy, either due to a slipped or to an intrathoracic fundoplication (17). The novel MS has been developed and validated in a surgery-naïve population with suspected GERD, assessing the competency of the anti-reflux barrier. The application of the score to a population of patients who underwent LARS is legitimated by the assumption that the pathophysiology of recurrent GERD follows the same pathway of GERD itself, with an anatomical and functional impairment of the LES-CD complex.

Our results showed that the manometric variables responsible for an abnormal MS and high symptom burden are a higher EGJ type and a positive response to the SLR maneuver. This is coherent with the findings of the original validation paper of the score (2), that identifies these two variables as the main manometric predictors of a pathologic reflux monitoring test. Only in the comparison according to RSI, a more intact EGJ was not associated with better outcomes, suggesting that atypical reflux symptoms might have a different pathophysiological pathway than typical symptoms (18,19). The same statistical relation between abnormal MS and worse outcomes was found segregating MSA and Toupet groups, demonstrating that the score is efficient in the discrimination of symptomatic patients regardless of the surgical technique. In all cases, worse symptoms burden and higher MS were related to a longer follow-up time, showing that time from surgery is a factor invariably related to the risk of recurrence.

Interestingly, patients with better outcomes according to GERD-Q showed a higher rate of dysphagia (13.3 vs. 28.7%, P=0.042 and FOSS ≥1: 9.8% vs. 37.7%, P<0.001). The statistical significance was maintained also when the FOSS score was analysed as a continuous variable (P<0.001). Even though in both groups the higher FOSS score was 1, indicating a mild dysphagia with minimal dietary changes and no weight loss, this result shows that a better control of reflux symptoms might be associated with a certain grade of relaxation impairment after restoration of the EGJ competency, as well known from previous literature (20-24).

In our study population, the ability of the score to predict an abnormal questionnaire demonstrated an AUC ranging from 0.696 of RSI to 0.765 of GERD-HRQL, with an optimal threshold for the MS ranging from 125 to 149. In the original paper, the AUC of the score in surgery naïve patients was 0.88 (95% CI: 0.84–0.92) with an optimal cut-off for the score of 137 (2). These differences, rather than a consequence of LARS, might be explained by a variety of confounding factors, including the smaller sample size, the heterogeneity in the study population and, first and foremost, the use of subjective evaluation of symptoms as outcome measure instead of the gold standard (pH-test). With all these limitations, the different thresholds of MS found in this study should not be recommended, and a new optimal cut-off for the score in patients after LARS has still to be determined in future studies.

MSA and Toupet fundoplication were the two most frequent surgical techniques in our series, representing together more than 80% of the overall sample size. MSA patients were significantly younger, had a lower rate of hiatoplasty and none of these patients underwent a mesh placement. These data might be explained by the fact that at the beginning of MSA experience, the magnetic sphincter was contraindicated in redo operations and in hiatal hernias larger than 3 cm (more frequent in older patients and more frequently associated with mesh placement) and crura repair was not routinely performed. In this series, about 37% of patients in the MSA group reported a certain grade of dysphagia, significantly more than the Toupet group (about 18%) and higher than the rates described by Sarici et al. (24) in their review, with rates ranging from 0 to 19% in the long-term. This might be explained by our inclusion of mild dysphagia (FOSS ≥1). We found similar results in terms of GERD symptoms control between the groups, with corresponding similar MS and risk classes for GERD. However, we found other manometric differences between MSA and Toupet, with higher LES basal pressure, EGJ-CI and IRP in the MSA group. These results are aligned with normal postoperative values reported in literature (25-27) and coherent with the different post-surgical anatomy, with a 360° anti-reflux system encircling the cardia compared to a partial wrap. Median DCI is higher in the MSA group, even without reaching statistical significance, as a response of esophageal contractility to a higher IRP (25,27).

Postoperative evaluation of the efficacy of LARS is complex and should be assessed by multiple perspectives, including control of reflux symptoms and patients’ satisfaction, integrity of post-surgical anatomy evaluated by means of upper endoscopy and barium swallow study, and by acid exposure in the distal esophagus, which is the gold standard to determine an efficient anti-reflux procedure. However, the reflux monitoring test, especially catheter based, is a poorly tolerated exam, and it is not indicated in a routine follow-up. The HRM with the inclusion of the MS might encompass many post-operative data, such as the integrity and the correct placement of the wrap, the EGJ competency and a risk rate of a positive reflux monitoring study (2), and might be a useful screening tool to determine which symptomatic patients should undergo a postoperative pH-test to confirm LARS failure. Moreover, in this retrospective series we demonstrated the association between MS and symptoms evaluated with validated questionnaires, confirming the ability of HRM to associate an objective and measurable data with the subjective evaluation of symptoms.

The strength of our study relies in the high numerosity of patients assessed with internationally validated questionnaires, endoscopy, barium swallow study and HRM with the inclusion of a novel manometric score that might become a useful screening tool for post-operative LARS assessment.

This study has also some limitations. The retrospective design and the high heterogeneity of the study population, which underwent surgery in a wide period of time, with different surgical techniques and in various surgical centers, might be confounding factors. The high rate of symptomatic patients reflects the fact that our center evaluates a significant rate of patients with LARS failure from our and other centers, referred for redo surgery. This explains the high prevalence of persistent symptoms and abnormal MS postoperatively, more than 40% in this study, significantly higher than the recurrence rates reported in literature, that are 5–15% in the long-term (28-31). Although this data does not reflect the success rate of a referral center, it provides a real-world scenario. Moreover, due to the wide time frame of the anti-reflux procedures, performed from 1999 to 2022, and to the lack of a proper data registry in our institution until the last decade, we are not able to provide retrospectively the total number of the laparoscopic anti-reflux procedures performed in our center during the same period of time. Another important limitation of this study is the absence of a post-operative pH-monitoring test, which is the gold standard to diagnose GERD recurrence as it provides an objective evaluation of the amount of acid exposure in the distal esophagus. As it is an invasive and poorly tolerated test, it was not routinely performed postoperatively and has become part of the routine follow-up after LARS in our center only in the last few years, reason why we could not retrieve that data retrospectively. Finally, the MS that we applied in a post-surgery population has been developed and validated in surgery-naïve patients, and normal reference values might be affected by this discrepancy.

In the future we aim to assess prospectively the role of the MS after LARS, evaluating its relation with a postoperative pH-study and its variation before and after surgery, and determining new reference values of the score for operated patients.

Conclusions

The MS is an efficient tool to assess the efficacy of anti-reflux surgery and to screen patients with suspected recurrence. Various surgical techniques have similar distribution in the different risk classes for GERD identified by the score and similar clinical results. HRM with the MS represents an easy and feasible assessment of surgical outcomes, providing an objective evaluation of the anti-reflux barrier after surgery.

Acknowledgments

Funding: None.

Footnote

Data Sharing Statement: Available at https://aoe.amegroups.com/article/view/10.21037/aoe-24-32/dss

Peer Review File: Available at https://aoe.amegroups.com/article/view/10.21037/aoe-24-32/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://aoe.amegroups.com/article/view/10.21037/aoe-24-32/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the institutional ethics board of I.R.C.C.S. Policlinico San Donato (No. HS-23-00139) and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Gyawali CP, Yadlapati R, Fass R, et al. Updates to the modern diagnosis of GERD: Lyon consensus 2.0. Gut 2024;73:361-71. [Crossref] [PubMed]
2. Siboni S, Sozzi M, Kristo I, et al. The Milan score: A novel manometric tool for a more efficient diagnosis of gastro-esophageal reflux disease. United European Gastroenterol J 2024;12:552-61. [Crossref] [PubMed]
3. DeMeester SR. Laparoscopic Hernia Repair and Fundoplication for Gastroesophageal Reflux Disease. Gastrointest Endosc Clin N Am 2020;30:309-24. [Crossref] [PubMed]
4. Salvador R, Pandolfino JE, Costantini M, et al. The Role of High-Resolution Manometry Before and Following Antireflux Surgery: The Padova Consensus. Ann Surg 2025;281:124-35. [Crossref] [PubMed]
5. Jones R, Junghard O, Dent J, et al. Development of the GerdQ, a tool for the diagnosis and management of gastro-oesophageal reflux disease in primary care. Aliment Pharmacol Ther 2009;30:1030-8. [Crossref] [PubMed]
6. Jonasson C, Wernersson B, Hoff DA, et al. Validation of the GerdQ questionnaire for the diagnosis of gastro-oesophageal reflux disease. Aliment Pharmacol Ther 2013;37:564-72. [Crossref] [PubMed]
7. Velanovich V. The development of the GERD-HRQL symptom severity instrument. Dis Esophagus 2007;20:130-4. [Crossref] [PubMed]
8. Belafsky PC, Postma GN, Koufman JA. Validity and reliability of the reflux symptom index (RSI). J Voice 2002;16:274-7. [Crossref] [PubMed]
9. Bhargava A, Varshney P, Saxena S, et al. Role of Reflux Symptom Index and Reflux Finding Score in Evaluation of Treatment Outcome in Patients with Laryngopharyngeal Reflux. Int J Phonosurgery Laryngol 2017;7:39-43. [Crossref]
10. Muddaiah D, Prashanth V, Vybhavi MK, et al. Role of Reflux Symptom Index and Reflux Finding Score in Diagnosing Laryngopharyngeal Reflux: A Prospective Study. Indian J Otolaryngol Head Neck Surg 2023;75:777-83. [Crossref] [PubMed]
11. Salassa JR. A functional outcome swallowing scale for staging oropharyngeal dysphagia. Dig Dis 1999;17:230-4. [Crossref] [PubMed]
12. Yadlapati R, Kahrilas PJ, Fox MR, et al. Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0 Neurogastroenterol Motil 2021;33:e14058. [Crossref] [PubMed]
13. Siboni S, Kristo I, Rogers BD, et al. Improving the Diagnostic Yield of High-Resolution Esophageal Manometry for GERD: The “Straight Leg-Raise” International Study. Clin Gastroenterol Hepatol 2023;21:1761-70.e1. [Crossref] [PubMed]
14. Nicodème F, Pipa-Muniz M, Khanna K, et al. Quantifying esophagogastric junction contractility with a novel HRM topographic metric, the EGJ-Contractile Integral: normative values and preliminary evaluation in PPI non-responders. Neurogastroenterol Motil 2014;26:353-60. [Crossref] [PubMed]
15. Müller DT, Parker B, Fletcher R, et al. High Resolution Manometry in a Functioning Fundoplication - Establishing a Standard Profile: Retrospective Chart Review. Ann Surg 2022;276:e764-9. [Crossref] [PubMed]
16. Rerych K, Kurek J, Klimacka-Nawrot E, et al. High-resolution Manometry in Patients with Gastroesophageal Reflux Disease Before and After Fundoplication. J Neurogastroenterol Motil 2017;23:55-63. [Crossref] [PubMed]
17. Hoshino M, Srinivasan A, Mittal SK. High-resolution manometry patterns of lower esophageal sphincter complex in symptomatic post-fundoplication patients. J Gastrointest Surg 2012;16:705-14. [Crossref] [PubMed]
18. Sakin YS, Vardar R, Sezgin B, et al. The diagnostic value of 24-hour ambulatory intraesophageal pH-impedance in patients with laryngopharyngeal reflux symptoms comparable with typical symptoms. United European Gastroenterol J 2017;5:632-40. [Crossref] [PubMed]
19. Wang AM, Wang G, Huang N, et al. Association between laryngopharyngeal reflux disease and autonomic nerve dysfunction. Eur Arch Otorhinolaryngol 2019;276:2283-7. [Crossref] [PubMed]
20. Zaninotto G, Portale G, Costantini M, et al. Long-term results (6-10 years) of laparoscopic fundoplication. J Gastrointest Surg 2007;11:1138-45. [Crossref] [PubMed]
21. Marjoux S, Roman S, Juget-Pietu F, et al. Impaired postoperative EGJ relaxation as a determinant of post laparoscopic fundoplication dysphagia: a study with high-resolution manometry before and after surgery. Surg Endosc 2012;26:3642-9. [Crossref] [PubMed]
22. Ayazi S, Zheng P, Zaidi AH, et al. Magnetic Sphincter Augmentation and Postoperative Dysphagia: Characterization, Clinical Risk Factors and Management. J Gastrointest Surg 2020;24:39-49. [Crossref] [PubMed]
23. Bologheanu M, Matic A, Feka J, et al. Severe Dysphagia is Rare After Magnetic Sphincter Augmentation. World J Surg 2022;46:2243-50. [Crossref] [PubMed]
24. Sarici IS, Dunn CP, Eriksson SE, et al. Long-term clinical and functional results of magnetic sphincter augmentation. Dis Esophagus 2023;36:doac109. [Crossref] [PubMed]
25. Weijenborg PW, Savarino E, Kessing BF, et al. Normal values of esophageal motility after antireflux surgery; a study using high-resolution manometry. Neurogastroenterol Motil 2015;27:929-35. [Crossref] [PubMed]
26. Riva CG, Siboni S, Sozzi M, et al. High-resolution manometry findings after Linx procedure for gastro-esophageal reflux disease. Neurogastroenterol Motil 2020;32:e13750. [Crossref] [PubMed]
27. Siboni S, Ferrari D, Riva CG, et al. Reference high-resolution manometry values after magnetic sphincter augmentation. Neurogastroenterol Motil 2021;33:e14139. [Crossref] [PubMed]
28. Hatlebakk JG, Zerbib F, Bruley des Varannes S, et al. Gastroesophageal Acid Reflux Control 5 Years After Antireflux Surgery, Compared With Long-term Esomeprazole Therapy. Clin Gastroenterol Hepatol 2016;14:678-85.e3. [Crossref] [PubMed]
29. Lundell L, Attwood S, Ell C, et al. Comparing laparoscopic antireflux surgery with esomeprazole in the management of patients with chronic gastro-oesophageal reflux disease: a 3-year interim analysis of the LOTUS trial. Gut 2008;57:1207-13. [Crossref] [PubMed]
30. Galmiche JP, Hatlebakk J, Attwood S, et al. Laparoscopic antireflux surgery vs esomeprazole treatment for chronic GERD: the LOTUS randomized clinical trial. JAMA 2011;305:1969-77. [Crossref] [PubMed]
31. Mittal SK, Bikhchandani J, Gurney O, et al. Outcomes after repair of the intrathoracic stomach: objective follow-up of up to 5 years. Surg Endosc 2011;25:556-66. [Crossref] [PubMed]