Review Reports - Laparoscopic Fundoplication Using the Excluded Stomach Versus Conversion to Roux-en-Y Gastric Bypass for Refractory Reflux After One-Anastomosis Gastric Bypass: A Retrospective Comparative Analysis of Safety and 1-Year Outcomes

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript addresses an important and clinically relevant issue concerning the management of refractory bile reflux after one-anastomosis gastric bypass (OAGB). The comparison between conversion to Roux-en-Y gastric bypass and fundoplication using the excluded stomach is original and potentially valuable for bariatric surgeons. The manuscript is generally well structured, and the surgical illustrations are informative.

However, some methodological and interpretative concerns should be addressed.

My comments are:

The two groups were not comparable because the choice of revisional procedure evolved over time rather than being based on predefined criteria (Methods, lines 19–23, Discussion, lines 13–18 on page 13).

Importantly, the fundoplication group had significantly longer intervals from OAGB to revision, significantly shorter postoperative follow-up, different historical periods of treatment, likely different surgical learning curve effects.

This substantially limits causal interpretation of the superiority of fundoplication.

The conclusions should be moderated, and the non-randomized temporal allocation should be emphasized as a major limitation already in the Abstract and Discussion.

The diagnosis of bile reflux relied mainly on symptoms, endoscopy, and RSI score, without objective functional assessment (Introduction, lines 15–18, Methods, lines 14–18 on page 6, Limitations, lines 24–33 on page 14).

No routine: pH impedance monitoring, bilitec monitoring, esophageal manometry, scintigraphy was performed.

Therefore, distinguishing between acid reflux, bile reflux, and mixed reflux remains uncertain.

The authors should more carefully acknowledge that the study evaluated “reflux symptoms after OAGB” rather than objectively confirmed bile reflux.

The fundoplication group included only 16 patients )Results, page 8, Tables 1–3).

Several conclusions are based on very small event numbers, resulting in extremely wide confidence intervals: OR 19.8 (95% CI 1.07–365); OR 12.07 (95% CI 0.64–227.3).

These estimates are unstable and should be interpreted cautiously.

The mean follow-up was: 5.4 years in the RY group, 2.8 years in the FP group (Results, lines 20–21 on page 9; Table 1).

This creates a major imbalance in the likelihood of detecting late complications and recurrence.

The statement that this “is unlikely to significantly impact the findings” is speculative (Discussion, lines 18–23 on page 14).

The authors should avoid overconfidence regarding long-term superiority of fundoplication.

All patients in the FP group underwent cruroplasty and hiatal hernia repair together with fundoplication (Surgical technique, lines 8–17 on page 7). However, it is unclear whether hiatal hernia repair was systematically performed in the RY group.

Thus, improved reflux control may partly reflect hiatal reconstruction rather than the fundoplication itself.

Please clarify whether hiatal repair was performed during RYGB conversion.

The title suggests a comparative efficacy study, although the design is retrospective and highly selected.
The manuscript alternates between: “bile reflux”, “GERD”, “mixed reflux”, “gastroesophageal reflux”.

Given the lack of objective reflux characterization, terminology should be standardized.

Several odds ratios are reported despite extremely small sample sizes and zero-event groups (Table 2, Table 3).

Please specify whether continuity correction or exact logistic methods were used.

Author Response

However, some methodological and interpretative concerns should be addressed.

My comments are:

The two groups were not comparable because the choice of revisional procedure evolved over time rather than being based on predefined criteria (Methods, lines 19–23, Discussion, lines 13–18 on page 13).

This substantially limits causal interpretation of the superiority of fundoplication.

The conclusions should be moderated, and the non-randomized temporal allocation should be emphasized as a major limitation already in the Abstract and Discussion.

We thank the reviewer for this important comment, with which we fully agree. We acknowledge that the non-randomized, time-dependent allocation of patients to the two revisional procedures is the most important limitation of this study, and we have made it explicit from the Abstract onward rather than only in the Discussion, and we have moderated our conclusions accordingly.

In the Abstract, Methods section, we added at the end of the sentence describing the choice of revisional procedure: ", reflecting a non-randomized, time-dependent allocation — a major limitation of this comparison."

In the Abstract, Conclusions section, we replaced our original conclusion with the following: "Fundoplication using the excluded stomach appears to be a feasible alternative to Roux-en-Y conversion for refractory reflux after OAGB, with favorable short-term outcomes. Given the non-randomized, time-dependent allocation, these findings are hypothesis-generating and require confirmation in larger, randomized studies."

In the Discussion, we rewrote the opening of the limitations paragraph to place this issue first and to address the different historical periods and the potential learning-curve effect. The paragraph now begins as follows: "This study has several limitations that should be acknowledged. The most important limitation is the non-randomized, time-dependent allocation of patients to the two revisional procedures, which was not based on predefined selection criteria but evolved as fundoplication using the excluded stomach was progressively introduced into clinical practice: early patients with refractory reflux were managed by conversion to RYGB, while fundoplication was proposed subsequently as experience with the technique accumulated. As a direct consequence, the two groups largely correspond to different historical periods, with the FP group treated more recently; this is reflected in the significantly longer interval between primary OAGB and revisional surgery in the FP group (81.9 ± 49.7 months versus 39.6 ± 32.6 months; p = 0.005) and in the significantly shorter postoperative follow-up available for this group (2.8 ± 1.8 years versus 5.4 ± 2.6 years; p = 0.005). This temporal separation also implies a potential learning-curve effect, as the overall experience of the surgical team and refinements in perioperative management accumulated over the study period and may have influenced outcomes independently of the procedure itself. For these reasons, the comparison between the two groups should be regarded as hypothesis-generating rather than demonstrative of a causal superiority of one technique over the other, and represents a substantial source of confounding that must be borne in mind when interpreting the comparative outcomes." The remainder of the paragraph, beginning with "Sample size remains relatively small...", is unchanged.

Finally, we moderated the concluding paragraph of the Discussion, which now reads: "In conclusion, within the limits of a non-randomized comparison subject to temporal and selection bias, fundoplication using the excluded stomach appears to be a feasible and promising alternative to Roux-en-Y conversion for the management of refractory reflux after OAGB. In this preliminary series, it was associated with favorable symptom control while preserving the original intestinal anatomy, thereby avoiding the morbidity associated with intestinal reconstruction — including the risk of internal hernia — which proved to be the principal driver of late complications in the RYGB group. The lower rate of reoperation for persistent reflux observed in the fundoplication group is encouraging but will require confirmation in larger, prospective, and ideally randomized cohorts before influencing clinical practice." In the following sentence, we replaced "may be especially advantageous in" with "may be especially worth investigating in" for consistency with this more cautious tone.

The diagnosis of bile reflux relied mainly on symptoms, endoscopy, and RSI score, without objective functional assessment (Introduction, lines 15–18, Methods, lines 14–18 on page 6, Limitations, lines 24–33 on page 14).

No routine: pH impedance monitoring, bilitec monitoring, esophageal manometry, scintigraphy was performed.

Therefore, distinguishing between acid reflux, bile reflux, and mixed reflux remains uncertain.

The authors should more carefully acknowledge that the study evaluated “reflux symptoms after OAGB” rather than objectively confirmed bile reflux.

We thank the reviewer for this important methodological point, with which we fully agree. In the absence of pH-impedance monitoring, Bilitec bile monitoring, esophageal manometry, or scintigraphy, the nature of reflux (acid, bile, or mixed) cannot be objectively characterized in our cohort, and we have revised the manuscript accordingly, including the title.

We have changed the title see comment 6 removing the term "Bile" to avoid implying objectively confirmed bile reflux.

In the Methods, "Study Design and Patient Selection," we added the following sentence immediately after the description of the clinical presentation of GERD after OAGB: " Given the lack of objective characterization by pH-impedance monitoring and/or Bilitec bile monitoring of the type of reflux (acid, biliary, or mixed) in our cohort, the term 'reflux' is used throughout this manuscript as the standard designation for the overall clinical and endoscopic entity studied.”

In the Discussion, Limitations paragraph, we expanded the sentence on the diagnostic limitations of our study, which now reads: "The diagnosis of reflux was mainly based on clinical symptoms and RSI score, without systematic use of objective functional tests such as pH-impedance monitoring, Bilitec bile monitoring, esophageal manometry, or scintigraphy, which could have provided a more precise characterization of reflux (acid vs bile vs mixed). As a result, this study should be regarded as an evaluation of reflux symptoms after OAGB and their response to revisional surgery, rather than of objectively confirmed and characterized bile reflux."

The fundoplication group included only 16 patients (Results, page 8, Tables 1–3).

Several conclusions are based on very small event numbers, resulting in extremely wide confidence intervals: OR 19.8 (95% CI 1.07–365); OR 12.07 (95% CI 0.64–227.3).

These estimates are unstable and should be interpreted cautiously.

We agree. The very wide confidence intervals around the odds ratios for reoperation (OR 19.8, 95% CI 1.07–365) and late complications (OR 12.07, 95% CI 0.64–227.3) reflect the small number of events, particularly in the FP group (n=16), and indicate limited precision of these estimates. We have added cautionary wording in the Results when these ORs are first reported, and reinforced this point in the Limitations, emphasizing that these estimates should be regarded as indicative rather than precise.

First, in the Results, "Reflux Outcomes" paragraph, after "...(p = 0.006; OR 19.8, 95% CI [1.07–365.5])." add: "given the small number of events, this estimate is imprecise and should be interpreted with caution."

Second, in the Results, "Postoperative Complications" paragraph, after "...(p = 0.035; OR: 12.07; 95% CI [0.6413–227.2897])." add: "again reflecting the small number of events and limited precision."

Third, in the Discussion, Limitations paragraph, after "Sample size remains relatively small, particularly in the fundoplication group, limiting the statistical power of the analysis." add: "resulting in very wide confidence intervals around key estimates, which should be interpreted as indicative rather than precise."

The mean follow-up was: 5.4 years in the RY group, 2.8 years in the FP group (Results, lines 20–21 on page 9; Table 1).

This creates a major imbalance in the likelihood of detecting late complications and recurrence.

The statement that this “is unlikely to significantly impact the findings” is speculative (Discussion, lines 18–23 on page 14).

The authors should avoid overconfidence regarding long-term superiority of fundoplication.

We agree that this statement was overconfident. We have removed the claim that the follow-up imbalance is unlikely to affect the findings, and instead acknowledge it explicitly as a limitation affecting the detection of late complications and recurrence, with no claim of confirmed long-term superiority of fundoplication.

In the Discussion, Limitations paragraph, replace the sentence "Follow-up duration was shorter in the fundoplication group compared to the RYGB group, which may underestimate the occurrence of late complications or reflux recurrence in this cohort. However, it is important to note that most reflux-related failures after revisional surgery tend to occur within the first postoperative year, which corresponds to the time frame of our primary endpoint. Therefore, the difference in follow-up duration is unlikely to significantly impact the main findings of this study regarding short-term reflux resolution." with: "Follow-up duration was also significantly shorter in the FP group compared to the RY group (2.8 ± 1.8 years versus 5.4 ± 2.6 years), creating a major imbalance in the likelihood of detecting late complications and reflux recurrence between the two groups. Although most reflux-related failures after revisional surgery tend to occur within the first postoperative year, corresponding to the time frame of our primary endpoint, longer follow-up in the FP group could still reveal additional late complications or recurrences not yet apparent, and any apparent long-term advantage of fundoplication over RYGB conversion therefore remains to be confirmed."

All patients in the FP group underwent cruroplasty and hiatal hernia repair together with fundoplication (Surgical technique, lines 8–17 on page 7). However, it is unclear whether hiatal hernia repair was systematically performed in the RY group.

Thus, improved reflux control may partly reflect hiatal reconstruction rather than the fundoplication itself.

Please clarify whether hiatal repair was performed during RYGB conversion.

We thank the reviewer for this important observation. Hiatal dissection and crural repair were not systematically performed during conversion to RYGB in our series, whereas in the FP group they were performed in all patients as an integral component of the fundoplication procedure, since reduction of the hiatal hernia and crural closure are prerequisites for constructing the wrap. We acknowledge that this represents a structural confounder inherent to the comparison, as hiatal repair cannot be dissociated from the fundoplication technique as performed. We have clarified the surgical technique description for the RY group accordingly, and expanded the Limitations section to state that part of the improved reflux control observed in the FP group may be attributable to hiatal reconstruction itself rather than to the fundoplication wrap alone, and that the relative contribution of each component cannot be determined from our data.

— Surgical Technique, "Conversion to Roux-en-Y Gastric Bypass"

After exploration of the abdominal cavity, the biliary limb was identified and its length measured. A jejunojejunal anastomosis was then created between the biliary limb adjacent to the gastrojejunal anastomosis and the efferent limb at a distance of approximately 70 cm from the gastrojejunal anastomosis. (Fig. 2) The biliary limb was subsequently divided between the two anastomoses using a linear stapler in order to separate the alimentary and biliary limbs. The procedure was completed by closure of the mesenteric defects, including Petersen's space and the jejunojejunal mesenteric defect. (Fig. 3) Hiatal dissection and crural repair were not performed as part of this procedure, regardless of the presence of hiatal hernia on preoperative imaging.

Discussion, Limitations

An additional structural confounder is that hiatal hernia repair was performed in all FP patients as an integral part of the fundoplication procedure, but not systematically in the RY group. Since hiatal closure is a prerequisite for constructing the wrap, this component cannot be dissociated from the fundoplication technique itself, and part of the superior reflux control observed in the FP group may be attributable to hiatal reconstruction rather than to the fundoplication wrap alone.

Discussion, mechanism paragraph

However, hiatal hernia repair, performed concomitantly in all FP patients but not in the RY group, may also contribute independently to this effect, and the relative contribution of crural closure versus the fundoplication wrap cannot be disentangled in the present study.

The title suggests a comparative efficacy study, although the design is retrospective and highly selected.

We agree that the original title implied a level of comparative efficacy evidence not supported by a retrospective, non-randomized, and highly selected cohort. We have revised the title to explicitly indicate its retrospective design.

Laparoscopic Fundoplication Using the Excluded Stomach versus Conversion to Roux-en-Y Gastric Bypass for Refractory Reflux after One-Anastomosis Gastric Bypass: A Retrospective Comparative Analysis of Safety and 1-Year Outcomes.

The manuscript alternates between: “bile reflux”, “GERD”, “mixed reflux”, “gastroesophageal reflux”.

Given the lack of objective reflux characterization, terminology should be standardized.

We agree that terminology should be standardized given the lack of objective reflux characterization. We have therefore adopted 'reflux' as the standard term used throughout the manuscript — including in the title — to designate the overall clinical entity studied, regardless of its underlying composition (acid, biliary, or mixed). We have revised the relevant instances in the Abstract, Introduction, Methods, Results, and Discussion accordingly, and have added a clarifying statement in the Methods specifying that 'reflux' is used as the standard designation throughout.

Methods, "Study Design and Patient Selection"

Given the lack of objective characterization by pH-impedance monitoring and/or Bilitec bile monitoring of the type of reflux (acid, biliary, or mixed) in our cohort, the term 'reflux' is used throughout this manuscript as the standard designation for the overall clinical and endoscopic entity studied.

Several odds ratios are reported despite extremely small sample sizes and zero-event groups (Table 2, Table 3).

Please specify whether continuity correction or exact logistic methods were used.

We thank the reviewer for raising this point. For the 2×2 tables containing zero-event cells (Table 2, late complications; Table 3, reoperation for persistent reflux), odds ratios and their 95% confidence intervals were calculated after applying the Haldane-Anscombe continuity correction, adding 0.5 to each cell of the contingency table, with confidence intervals derived using Woolf's method on the log-odds scale. We have specified this in the Statistical Analysis section.

Statistical Analysis

For 2×2 tables containing at least one zero-event cell (Tables 2 and 3), odds ratios and their 95% confidence intervals were calculated after applying the Haldane-Anscombe continuity correction (adding 0.5 to each cell), with confidence intervals derived using Woolf's method on the log-odds scale.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript complies with ethical guidelines and policies, fits within the scope of the journal, the figures and tables do not require clarification from the authors, all data are available, and the linguistic quality is adequate for peer review.

However, I would like to make a few comments:

It is known that the incidence of reflux in the literature for the described surgical technique (OAGB) can approach 30% (Ghiassi S et al., Felsenreich DM et al.), while the authors mention 10% in the introduction.

What diagnostic tests were performed on the patients before the first surgery? How many of these patients at that time might already have had a hiatal hernia and reflux? Many patients with gastroesophageal reflux disease have mixed reflux.

If gastric banding is a risk factor for the development of postoperative reflux in OAGB, why was this technique chosen initially?

To what do they attribute the need for reintervention in 10 patients in the group who underwent conversion to Roux-en-Y gastric bypass? What is the length between the gastrojejunal anastomosis and the foot of the loop? Is it always the same?
How many surgeons performed these reinterventions for bypass or fundoplication?

As the authors note, the study has limitations:
Small sample size despite the data collection period.
Potential biases due to the inability to use objective functional tests to quantify and demonstrate this reflux.
Single-center, retrospective study.

Author Response

However, I would like to make a few comments:

It is known that the incidence of reflux in the literature for the described surgical technique (OAGB) can approach 30% (Ghiassi S et al., Felsenreich DM et al.), while the authors mention 10% in the introduction.

We thank the reviewer for this observation and agree that the incidence figure originally cited likely underrepresents the rates reported in more recent series. We have revised the corresponding sentence in the Introduction to reflect the wider range reported in the literature, citing Ghiassi et al. and Felsenreich et al. accordingly.

In the Introduction, first paragraph, the sentence "Although the true incidence varies among series, biliary reflux has been reported in approximately 5–10% of patients and may significantly impair postoperative quality of life.[3]" was replaced by "Although the true incidence varies among series, reflux after OAGB has been reported in approximately 5–10% of patients in earlier series[3], whereas more recent studies report rates approaching 30%[ Ghiassi S, Nimeri A, Aleassa EM, Grover BT, Eisenberg D, Carter J; American Society for Metabolic and Bariatric Surgery Clinical Issues Committee. American Society for Metabolic and Bariatric Surgery position statement on one-anastomosis gastric bypass. Surg Obes Relat Dis. 2024 Apr;20(4):319-335. doi: 10.1016/j.soard.2023.11.003. Epub 2023 Nov 23. PMID: 38272786. Felsenreich DM, Vock N, Zach ML, Kristo I, Jedamzik J, Bichler C, Eichelter J, Mairinger M, Gensthaler L, Nixdorf L, Richwien P, Pedarnig L, Langer FB, Prager G. Update on esophageal function, acid and non-acid reflux after one-anastomosis gastric bypass (OAGB): high-resolution manometry, impedance-24-h pH-metry, and gastroscopy in a prospective mid-term study. Surg Endosc. 2025 Apr;39(4):2335-2345. doi: 10.1007/s00464-025-11606-7. Epub 2025 Feb 18. PMID: 39966130; PMCID: PMC11933198. ], and it may significantly impair postoperative quality of life."

What diagnostic tests were performed on the patients before the first surgery? How many of these patients at that time might already have had a hiatal hernia and reflux? Many patients with gastroesophageal reflux disease have mixed reflux.

The work-up described in the "Preoperative Assessment" section refers to the assessment performed before revisional surgery, not before the index bariatric procedure. For a substantial proportion of patients — particularly those whose index procedure was adjustable gastric banding performed years earlier, often by different surgical teams — endoscopic and radiological data from the time of the index surgery were not available, and it was therefore not possible to determine retrospectively whether a hiatal hernia or reflux was already present at that time. We have clarified the timeframe of the preoperative work-up in the Methods and added this point as an additional limitation in the Discussion. The characterization of mixed reflux is addressed in our response to Reviewer 1, Comment 2.

In the Methods, "Preoperative Assessment," the sentence "According to French national recommendations, all patients underwent preoperative esophagogastroduodenoscopy (EGD) with systematic biopsies." was replaced by "According to French national recommendations, all patients underwent esophagogastroduodenoscopy (EGD) with systematic biopsies prior to revisional surgery."

In the Discussion, Limitations, the following sentence was added: "In addition, for a substantial proportion of patients — particularly those with a history of adjustable gastric banding performed years earlier, often by different surgical teams — preoperative endoscopic and radiological data from the time of the index bariatric procedure were not available, precluding any retrospective assessment of pre-existing hiatal hernia or reflux at that time."

If gastric banding is a risk factor for the development of postoperative reflux in OAGB, why was this technique chosen initially?

Adjustable gastric banding was, in most cases, performed years before the index OAGB (or before conversion to OAGB), often by different surgical teams, at a time when AGB was widely used as a first-line bariatric procedure and a small hiatal hernia was not systematically regarded as a contraindication. The association between a history of AGB and an increased risk of reflux after subsequent OAGB has only been established in more recent literature, well after these index procedures had been performed. The choice of AGB therefore reflects the bariatric surgical standards of the period in which these patients were initially operated, rather than a decision made with prior knowledge of its later-recognized association with reflux after OAGB.

In the Discussion, pathophysiology paragraph, after the sentence on AGB as a risk factor, the following sentence was added: "It should be noted that adjustable gastric banding, when present, was in most cases performed years earlier, often by different surgical teams, at a time when AGB was a widely used first-line bariatric procedure and a small hiatal hernia was not systematically considered a contraindication; the association between a history of AGB and an increased risk of reflux after OAGB conversion has only been established in more recent literature, after these index procedures had already been performed."

To what do they attribute the need for reintervention in 10 patients in the group who underwent conversion to Roux-en-Y gastric bypass? What is the length between the gastrojejunal anastomosis and the foot of the loop? Is it always the same? How many surgeons performed these reinterventions for bypass or fundoplication?

The indication for reintervention in all 10 patients of the RY group was persistent reflux, as already stated in the Results. The index OAGB procedures were all performed with a standardized omega-loop configuration and a biliopancreatic limb length of 200 cm, constant across patients. Regarding the surgical team, all laparoscopic fundoplication procedures (FP group) were performed by a single surgeon, whereas the conversions to Roux-en-Y gastric bypass (RY group) were performed by two other surgeons during an earlier period of the study.

In the Methods, "Study Design and Patient Selection," the following sentence was added: "All index OAGB procedures were performed using a standardized omega-loop configuration with a biliopancreatic limb length of 200 cm."

In the Methods, "Surgical Technique," after the sentence "All procedures were performed laparoscopically.", the following sentence was added: "Conversions to Roux-en-Y gastric bypass were performed by two surgeons during an earlier period of the study, whereas laparoscopic fundoplication using the excluded stomach was performed by a single surgeon."

In the Discussion, Limitations, the sentence "...and may have influenced outcomes independently of the procedure itself." was followed by the addition of: "This is further reflected in the fact that conversions to Roux-en-Y gastric bypass were performed by two surgeons during an earlier period, whereas fundoplication procedures were all performed by a single surgeon, introducing an additional surgeon-related source of variability that cannot be disentangled from the comparison."

As the authors note, the study has limitations: small sample size despite the data collection period; potential biases due to the inability to use objective functional tests to quantify and demonstrate reflux; single-center, retrospective study.

These points have already been addressed in detail in response to Reviewer 1. The limited sample size, particularly in the fundoplication group, and the resulting very wide confidence intervals around key estimates, are now explicitly acknowledged in the Limitations section (response to Reviewer 1, Comment 3). The inability to objectively characterize and quantify reflux using pH-impedance monitoring, Bilitec bile monitoring, esophageal manometry, or scintigraphy is now stated as a major limitation, and the study has been reframed accordingly as an evaluation of reflux symptoms and their response to revisional surgery rather than of objectively confirmed reflux (response to Reviewer 1, Comment 2). The single-center, retrospective nature of the study, performed by experienced surgeons, is acknowledged in the final sentence of the Limitations paragraph. No further text change is proposed for this comment.

Reviewer 3 Report

Comments and Suggestions for Authors

The paper is presenting a comparison of two surgical procedures in order to treat the persistent biliary reflux after one-anastomosis gastric bypass (OAGB). The authors compared the laparoscopic fundoplication using the excluded stomach versus conversion to Roux-en-Y gastric bypass (RYGB) and the outcomes after 1 year. A total of 43 patients were included: 27 in the RYGB group and 16 in the fundoplication group.

The introduction present the surgical techniques and reflux after OAGB but they have to detail the pathophysiology of the reflux searching more in the medical literature in order to explain to the readers. "The characterization of reflux following OAGB remains challenging" .

The material and methods describe study design, patient selection and surgical techniques.

As for the results at 12 months, they are fine, with complete resolution of reflux symptoms was observed in 55.6% of patients in the RYGB group versus 93.7% in the fundoplication group. Persistent reflux requiring reoperation occurred in 10 patients (37%) in the RYGB group, while no reoperations were required in the fundoplication group. Late complications were significantly higher after RYGB conversion (25.9% vs 0%),, mainly due to internal hernias. Reflux Symptoms Index (RSI) scores significantly improved in both groups, with no significant difference in postoperative values.

The discussions are relevant for this study presenting data from the medical literature and comparing the results with other ones.

The conclusions must be more organized and the reader must see where it starts.

The references, tables and images are appropriate.

Author Response

The paper is presenting a comparison of two surgical procedures in order to treat the persistent biliary reflux after one-anastomosis gastric bypass (OAGB). The authors compared the laparoscopic fundoplication using the excluded stomach versus conversion to Roux-en-Y gastric bypass (RYGB) and the outcomes after 1 year. A total of 43 patients were included: 27 in the RYGB group and 16 in the fundoplication group.

We thank the reviewer for this accurate summary of our study design and patient population.

The introduction presents the surgical techniques and reflux after OAGB but they have to detail the pathophysiology of the reflux searching more in the medical literature in order to explain to the readers.

We thank the reviewer for this suggestion and have expanded the Introduction to detail the pathophysiological mechanisms underlying reflux after OAGB.

In the Introduction, first paragraph, after the sentence "The characterization of reflux following OAGB remains challenging.", the following sentences were added: "From a pathophysiological standpoint, the blind gastric pouch and the single gastrojejunal anastomosis create a low-resistance conduit through which biliopancreatic secretions can reflux and pool within the pouch, particularly when the pouch is long or the anastomosis is wide, increasing exposure of the gastric and esophageal mucosa to bile and pancreatic enzymes[Ferrer-Márquez et al.]. This alkaline, enzyme-rich refluxate appears more injurious to the esophageal mucosa than acid alone, and combined acid-biliary (mixed) reflux has been documented on impedance-pH monitoring in a substantial proportion of patients after OAGB[Felsenreich et al.]."

The material and methods describe study design, patient selection and surgical techniques.

We thank the reviewer for confirming that the Methods section adequately describes the study design, patient selection, and surgical techniques.

As for the results at 12 months, they are fine, with complete resolution of reflux symptoms was observed in 55.6% of patients in the RYGB group versus 93.7% in the fundoplication group. Persistent reflux requiring reoperation occurred in 10 patients (37%) in the RYGB group, while no reoperations were required in the fundoplication group. Late complications were significantly higher after RYGB conversion (25.9% vs 0%), mainly due to internal hernias. Reflux Symptoms Index (RSI) scores significantly improved in both groups, with no significant difference in postoperative values.

We thank the reviewer for confirming that the Results section is clear and complete.

The discussions are relevant for this study presenting data from the medical literature and comparing the results with other ones. I think there are not many reports in the literature for this technique.

We thank the reviewer for this observation. As already noted in the Discussion, our study provides one of the few direct comparisons available in the literature between fundoplication using the excluded stomach and conversion to Roux-en-Y gastric bypass for refractory reflux after OAGB, and this scarcity of comparative data is part of the rationale for our work.

The conclusions must be more organized and the reader must see where it starts.

We thank the reviewer for this suggestion and have added a dedicated heading to clearly delimit the Conclusion as a separate section.

Before the paragraph beginning "In conclusion, within the limits of a non-randomized comparison subject to temporal and selection bias, fundoplication using the excluded stomach appears to be a feasible and promising alternative...", the following section heading was added: "Conclusion".

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have carefully revised the manuscript and have satisfactorily addressed the major concerns raised in the previous review. The revised version is considerably improved in terms of methodological transparency, interpretation of the findings, and overall scientific rigor.

In particular, the authors have:

- revised the title to better reflect the retrospective comparative design of the study;

- standardized the terminology throughout the manuscript by consistently referring to "reflux" rather than implying objectively confirmed bile reflux;

- clearly acknowledged the non-randomized, time-dependent allocation of patients as the major limitation of the study in both the Abstract and Discussion;

- expanded the limitations section by discussing temporal allocation bias, learning-curve effects, surgeon-related variability, differences in follow-up duration, and the absence of objective functional reflux assessment;

- clarified that hiatal hernia repair was systematically performed only in the fundoplication group and appropriately recognized this as an important structural confounder;

- added an explanation of the statistical methods used for odds ratio estimation in zero-event tables;

- moderated the conclusions appropriately, emphasizing that the findings should be regarded as hypothesis-generating.

Overall, these revisions substantially strengthen the manuscript.

Nevertheless, I have some minor comments:

- the authors appropriately acknowledge the lack of pH-impedance monitoring, Bilitec monitoring, and manometry. However, this limitation should also be briefly mentioned in the Conclusions to emphasize that the reported outcomes primarily reflect symptom improvement rather than objectively confirmed reflux control.

- the manuscript has markedly improved linguistically. Nevertheless, a final careful proofreading would still be beneficial, as several sentences remain unnecessarily long and could be simplified to improve readability.

Author Response

We sincerely thank the Reviewer for the thorough and constructive evaluation of our revised manuscript, and for acknowledging the improvements made in the previous revision. We have carefully addressed the two remaining minor comments as detailed below.

Comment 1: The authors appropriately acknowledge the lack of pH-impedance monitoring, Bilitec monitoring, and manometry. However, this limitation should also be briefly mentioned in the Conclusions to emphasize that the reported outcomes primarily reflect symptom improvement rather than objectively confirmed reflux control.

Response: We thank the Reviewer for this pertinent suggestion. We have added the following sentence to the Conclusions section:

"It should also be noted that, in the absence of objective functional assessment — including pH-impedance monitoring, Bilitec bile monitoring, and esophageal manometry — the reported outcomes reflect symptom improvement as evaluated by the RSI score, rather than objectively confirmed reflux control."

Comment 2: The manuscript has markedly improved linguistically. Nevertheless, a final careful proofreading would still be beneficial, as several sentences remain unnecessarily long and could be simplified to improve readability.

Response: We thank the Reviewer for this observation. The manuscript has undergone a thorough additional proofreading, with particular attention to sentence length and readability. Several passages throughout the text have been restructured and simplified accordingly. We believe these revisions further improve the overall clarity and fluency of the manuscript.