Short-Term Outcomes After the Introduction of Valvuloplastic Esophagogastrostomy via the Double-Flap Technique: Safe Robot-Assisted Implementation, Antireflux Efficacy, and Nutritional Impact

Short-Term Outcomes After the Introduction of Valvuloplastic Esophagogastrostomy via the Double-Flap Technique: Safe Robot-Assisted Implementation, Antireflux Efficacy, and Nutritional Impact | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Short-Term Outcomes After the Introduction of Valvuloplastic Esophagogastrostomy via the Double-Flap Technique: Safe Robot-Assisted Implementation, Antireflux Efficacy, and Nutritional Impact Naoto Takahashi, Shigeaki Baba, Haruka Nikai, Ryosuke Fujisawa, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8520885/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Introduction: Proximal gastrectomy (PG) has recently gained attention as a minimally invasive surgical option and a function-preserving surgery for early gastric cancer in the upper stomach. Among the various reconstruction methods following proximal gastrectomy, the double-flap technique (DFT) has been reported to provide effective anti-reflux function. In this study, we introduced the valvuloplastic esophagogastrostomy by double flap technique (VEG-DFT) and retrospectively compared its short-term outcomes with those of the conventional side-overlap (SO) method. Methods A total of 24 patients with cT1bN0M0 early gastric cancer located in the upper third of the stomach underwent VEG at our institution between January 2020 and July 2024. Of these, 14 underwent VEG-SO (SO group), and 10 underwent VEG-DFT (DFT group). Results Operative time, intraoperative blood loss, and the incidence of perioperative complications (Clavien–Dindo grade ≥ II) were comparable between the two groups. Postoperative upper gastrointestinal contrast studies and endoscopy revealed a significantly lower incidence of gastroesophageal reflux disease in the DFT group. No cases of anastomotic stenosis or leakage were observed in either group. Although serum nutritional indicators—including albumin and prealbumin—showed no significant differences between groups at six months postoperatively, body weight loss was significantly greater in the DFT group. Conclusion DFT may influence postoperative eating behavior, potentially due to increased passage resistance or early satiety. VEG-DFT was safely introduced and demonstrated favorable reflux control. Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Recently, there has been a reported increase in the incidence of upper-third gastric and esophagogastric junction cancers [ 1 , 2 ], for which proximal gastrectomy (PG) has been recommended as a function-preserving surgical procedure [ 3 ]. Compared with total gastrectomy (TG), PG better maintains postoperative nutritional status and body weight [ 4 ]. However, attention must be paid to anastomosis-related complications, such as anastomotic stricture and reflux esophagitis, which can lead to postoperative weight loss [ 5 ]. Various reconstruction techniques have been developed for valvuloplastic esophagogastrostomy (VEG), including the double-tract method, jejunal interposition [ 6 ], the side-overlap (SO) method [ 7 ], and the Side Overlap with Fundoplication by Yamashita (SOFY) method [ 8 ]. Another, the double-flap technique (DFT) method was first described by Kamikawa et al. in 2001 [ 9 ]. Several studies have demonstrated the safety and low incidence of anastomotic complications when DFT in VEG [ 10 , 11 ]. However, DFT is technically demanding due to the complexity of flap creation and suturing as well as the large number of sutures required. These factors contribute to prolonged operative time and increased procedural difficulty. Therefore, standardization and simplification of the technique are warranted. Robot-assisted gastrectomy was approved for national insurance coverage in Japan in 2018, and multicenter prospective studies have shown its superiority in terms of minimal invasiveness compared with laparoscopic surgery [ 12 ]. Robotic surgery may offer advantages in performing DFT reconstruction due to its three-dimensional visualization and articulated instruments. Nevertheless, since DFT is performed entirely by hand-sewn sutures in both laparoscopic and robotic approaches, the absence of tactile feedback may lead to excessive suture tension, increasing the risk of tissue damage, impaired anastomotic blood flow, and stricture. Conversely, insufficient tension may result in anastomotic leakage or reflux esophagitis. Moreover, robotic surgery carries specific risks, such as inadvertent injury to surrounding tissues due to blind spots and operational errors during instrument exchange. Given these concerns, evaluating the safety of robotic VEG-DFT during its introductory phase is imperative, as evidence regarding its early adoption remains limited [ 13 ]. At our institution, the SO method has been employed as a reconstruction technique for VEG in patients with early-stage upper gastric cancer. To further reduce postoperative reflux esophagitis, VEG-DFT was introduced in August 2023. In this study, we compare the short-term outcomes of patients who underwent SO and DFT following the introduction of VEG-DFT. Materials and Methods Subjects and Indications From January 2020 to February 2024, we enrolled 20 patients with early gastric cancer who had been diagnosed preoperatively with cT1bN0M0 Stage I disease according to the 15th edition of the Japanese Classification of Gastric Carcinoma. The indications for PG were as follows: (1) tumors localized to the upper third of the stomach, (2) tumor invasion limited to the muscularis propria, and (3) no evidence of lymph node metastasis on preoperative or intraoperative assessment. Surgical procedures, including the extent of lymph node dissection, were determined in accordance with the Japanese Gastric Cancer Treatment Guidelines, 7th edition [3]. We introduced the DFT procedure in October 2023 and applied it to all subsequent VEG cases. Patients treated up to September 2023 were classified into the SO group, whereas those treated from October 2023 onward were classified into the DFT group. All operations were performed by two board-certified gastrointestinal surgeons with more than 20 years of clinical experience. The da Vinci Surgical System Xi (Intuitive Surgical, USA) was used for all robot-assisted procedures. All patients were fully involved in the decision-making process, and written informed consent was obtained from each participant. This study was conducted with the approval of the Ethics Committee of Iwate Medical University (Approval No. MH2022-119). Surgical Procedure Robotic PG Robotic PG was performed using a five-port configuration with a Nathanson liver retractor (Yufu Itonaga, Tokyo, Japan) (Figure 1). The robot was rolled in from the patient’s right side, and the third robotic arm was positioned on the patient’s left side to prioritize right-hand instrument control. The extent of lymph node dissection, were determined in accordance with the Japanese Gastric Cancer Treatment Guidelines, 7th edition [3]. After mobilization around the esophagogastric junction, the abdominal esophagus was transected via the assistant port using the Signia™ stapling system with a 60-mm purple cartridge (Medtronic, Tokyo, Japan). The gastric body was subsequently divided using the same stapling system with two to three 60-mm purple cartridges. VEG-DFT In the DFT group, VEG was performed as follows. After specimen extraction through a mini-laparotomy, a seromuscular flap (width 2.5 cm × height 3.5 cm) was created on the remnant stomach outside the body cavity. An anastomotic opening measuring 2.5 cm was made at the lower edge of the flap (Figure 2A), and the anastomosis was completed intraperitoneally. The abdominal esophagus was mobilized approximately 5 cm longitudinally from the hiatus to secure adequate mobility from the gastric resection margin to the planned anastomotic site. The remnant stomach was anchored to the right and left diaphragmatic crura using 2-0 PDS® (Johnson & Johnson MedTech, Tokyo, Japan) (Figure 2B). Subsequently, five fixation sutures were placed between the posterior esophageal wall located 5 cm above the resection margin and the upper edge of the flap on the anterior wall of the remnant stomach using 3-0 Vicryl® (Johnson & Johnson MedTech, Tokyo, Japan) (Figure 2C). After fixation, the esophageal lumen was opened by cutting the staple line of the esophageal stump, and the cranial side of the anastomosis was sutured full-thickness with interrupted 3-0 Vicryl® stitches (Figure 2D). The caudal side was then similarly sutured full-thickness, followed by interrupted seromuscular–adventitial sutures between the remnant stomach and esophagus to complete closure (Figure 2E). After the anastomotic closure, the bilateral seromuscular flaps created on the remnant stomach were approximated with interrupted sutures and secured anteriorly over the anastomosis (Figure 2F). Anastomotic patency and absence of air leakage were confirmed using intraoperative endoscopy. VEG-SO In the SO group, VEG was performed as follows. After specimen extraction through a mini-laparotomy, a small enterotomy was created on the anterior wall of the remnant stomach approximately 5 cm distal to the gastric transection margin. Anastomosis was then completed intraperitoneally. A small opening was made on the left side of the esophageal stump, and the Signia™ stapling system with a 60-mm purple cartridge was inserted and rotated 90° counterclockwise to create the anastomosis between the esophagus and the anterior gastric wall. The stapler entry hole was closed in a slit-like fashion using 4-0 V-Loc™ (Covidien, Mansfield, USA) continuous Albert–Lembert sutures. The esophagus was additionally fixed to the anterior wall of the remnant stomach with interrupted 3-0 Vicryl® sutures [7]. Postoperative Management Postoperatively, patients resumed oral intake with an enteral formula on postoperative day (POD) 1. Based on a comprehensive assessment of laboratory findings and abdominal examinations, they were advanced to regular meals between POD 3 and 5. Regarding proton pump inhibitor (PPI) therapy, patients who had been taking PPIs preoperatively continued them after surgery. New PPI therapy was initiated in those who developed postoperative reflux symptoms—such as heartburn, chest discomfort, or pain—or in those diagnosed with Grade A or higher reflux esophagitis according to the revised Los Angeles classification on endoscopic examination at 6 months postoperatively. PPI therapy was discontinued at outpatient follow-up visits at 1, 3, 6, and 12 months after surgery if symptoms had resolved and endoscopic findings had improved. Definition of Complications We evaluated perioperative complications (Clavien–Dindo classification [14], Grade II or higher), gastroesophageal reflux on upper gastrointestinal contrast studies at 1 month postoperatively, endoscopic findings at 6 months postoperatively (reflux esophagitis assessed according to the revised Los Angeles classification [15], and anastomotic stricture defined as the ability of a 10mm diameter endoscope tip to pass through the anastomosis), reflux-related symptoms associated with anastomotic stricture during the first postoperative year. For all patients, serum prealbumin levels were measured on postoperative day 7, regardless of the surgical technique. At the 6-month follow-up visit, total lymphocyte count (TLC) and serum albumin (Alb), cholinesterase (CHE), and total cholesterol (TC) levels were measured. The postoperative change rate in prealbumin was calculated based on preoperative values. For Alb and CHE, change rates at 6 months were also calculated relative to the preoperative baseline. Similarly, postoperative body weight loss at 6 months was calculated using preoperative weight as 100%. Controlling Nutritional Status (CONUT) scores [16] were calculated based on Alb, TC, and TLC and compared between preoperative and 6-month postoperative values. Continuous variables were presented as medians with ranges and compared using the Student’s t-test or Mann–Whitney U test, as appropriate. Categorical variables were analyzed using the chi-square test or Fisher’s exact test when expected cell counts were insufficient. To complement hypothesis testing and avoid overinterpretation of non-significant results given the limited sample size, effect sizes for categorical outcomes were reported as odds ratios (ORs) with 95% confidence intervals. A two-sided P value <0.05 was considered statistically significant. All statistical analyses were performed using JMP® Pro version 13.0.0 (SAS Institute, Cary, NC, USA). Results Patient Background The baseline characteristics of the SO and DFT groups are summarized in Table 1. Among the 24 patients who underwent robotic PG, 14 were classified into the SO group and 10 into the DFT group. There were no significant differences between the groups in terms of sex, body mass index (BMI), American Society of Anesthesiologists physical status (ASA-PS), preoperative tumor depth, pathological tumor depth, pathological lymph node metastasis, or postoperative stage. Although not statistically significant, body weight tended to be slightly lower in the DFT group ( p = 0.057). A significantly higher number of patients in the DFT group had a history of abdominal surgery ( p = 0.016). Surgical Outcomes and Postoperative Complications In the DFT group, the median operative time was 361 minutes (range: 297–426 minutes) and the median blood loss was 22.5 mL (range: 15.8–37.0 mL). There were no significant differences between the SO and DFT groups in operative time, blood loss, or incidence of postoperative complications classified as Clavien–Dindo grade II or higher (Table 2). Upper gastrointestinal contrast studies showed no reflux of contrast into the esophagus in any patient, and the incidence of reflux esophagitis—assessed using the modified Los Angeles classification—was significantly lower in the DFT group ( p = 0.031) (Table2, Figure 3). No patients exhibited symptoms of stricture, and no obvious strictures were identified on contrast imaging. Body Weight Changes and Nutritional Indicators A significant decrease in body weight was observed in the DFT group compared with the SO group, even though the DFT group had a lower baseline body weight ( p = 0.034). No significant differences were observed between the two groups in any of the blood-based nutritional parameters (Figure 4). Discussion The primary aim of this study was to evaluate the safety and short-term oncologic, functional, and nutritional outcomes of robot-assisted VEG-DFT during its introductory phase, and to compare these outcomes with those of the conventional SO method. In particular, we sought to determine whether the adoption of VEG-DFT could reduce postoperative reflux while maintaining acceptable operative safety and nutritional preservation. This study demonstrated that the introduction of robotic VEG-DFT was feasible and safe, with no significant differences from the SO method in operative time, blood loss, or the incidence of Clavien–Dindo grade II or higher complications. Importantly, postoperative upper gastrointestinal contrast studies revealed no reflux in either group, but endoscopic assessment showed a significantly lower incidence of reflux esophagitis in the DFT group. No anastomotic strictures or stricture-related symptoms occurred in either cohort. Although patients in the DFT group experienced greater postoperative weight loss despite having a lower baseline body weight, no significant differences were observed in blood-based nutritional parameters—including Alb, CHE, TC, TLC, or prealbumin—at 6 months postoperatively. Reflux esophagitis after PG is primarily associated with disruption of the physiological anti-reflux mechanism, particularly loss of lower esophageal sphincter (LES) function and the angle of His. This anti-reflux barrier comprises the LES, angle of His, diaphragmatic crura, and phrenoesophageal ligament [ 17 ]. The LES functions as a high-pressure zone at the distal esophagus, while the angle of His contributes to a flap–valve mechanism at the esophagogastric junction. Hill et al. demonstrated that a well-formed flap valve observed endoscopically is associated with a lower risk of reflux esophagitis [ 18 ]. Following surgery for upper gastric or esophagogastric junction cancer, these anatomical structures are often disrupted. Therefore, reconstruction techniques that restore these anti-reflux mechanisms are essential after PG. At our institution, the SO method had been used as the standard reconstruction following proximal gastrectomy. This technique creates an artificial valve by suturing the esophagus to the gastric wall, reconstructing the angle of His and a pseudo-fundus to prevent reflux through compression of the lower esophagus during increases in intragastric pressure [ 19 , 20 ]. However, postoperative reflux symptoms and esophagitis still occurred in some patients, suggesting that the anti-reflux effect of the SO method may be insufficient in certain cases. To address this limitation, we introduced the DFT as an alternative anti-reflux reconstruction. In the present study, the DFT group showed a significantly lower incidence of postoperative reflux esophagitis than the SO group, with no cases of grade A or higher esophagitis according to the modified Los Angeles classification. Endoscopic findings at 6 months postoperatively demonstrated formation of a pseudo-fundus in the remnant stomach, indicating a favorable anastomotic configuration. Notably, no anastomosis-related complications, including leakage or postoperative abscess, were observed in the DFT group. Importantly, performing DFT under robot-assisted surgery allows for precise flap creation and meticulous suturing using articulated instruments and three-dimensional visualization, enabling accurate reconstruction of the anti-reflux mechanism while minimizing tissue trauma. This technical advantage facilitates functional preservation with minimal invasiveness. As previously described by Tanaka et al. [ 21 ], DFT embeds the distal esophagus within the submucosal layer of the remnant stomach, where it is compressed by intragastric pressure and the seromuscular flap, functioning as a valve. In addition, coverage of the anterior anastomotic wall by the seromuscular flap may contribute to the low risk of anastomotic leakage. In our series, DFT was introduced safely without significantly increasing operative time, blood loss, postoperative complications, or length of hospital stay compared with the SO method, and reconstruction time was comparable between the two techniques. Although blood-based nutritional parameters did not significantly deteriorate in the DFT group, postoperative weight loss was more pronounced. This discrepancy may be explained by several factors. First, while DFT effectively prevents reflux, the flap structure at the anastomosis may alter food passage, potentially leading to early satiety or postprandial discomfort and reduced oral intake, even in the absence of evident stricture or reflux. However, mechanical resistance and subjective symptoms were not evaluated in this study, and this interpretation remains speculative. Second, blood-based nutritional markers primarily reflect short-term protein metabolism and immune status and may not adequately capture chronic nutritional deficits such as reduced caloric intake or sarcopenia. Consequently, loss of lean body mass may have progressed without detectable changes in laboratory parameters. In addition, patients in the DFT group tended to have lower preoperative body weight and had a significantly higher prevalence of prior abdominal surgery, which may have influenced baseline digestive and absorptive capacity. Future studies should incorporate detailed dietary assessments, gastrointestinal functional evaluation, and body composition analysis to better clarify the mechanisms underlying postoperative weight loss. This study has several limitations. It was conducted at a single institution using a retrospective design and did not include patient-reported outcomes or quality-of-life assessments based on validated questionnaires. Although the present results confirm the feasibility and safety of introducing the DFT in a robot-assisted setting, the sample size remains insufficient for robust multivariable analysis. In addition, this was not a randomized study, and long-term follow-up has not yet been completed. These limitations may affect the generalizability of our findings. Declarations Conflict of Interest The authors declare no conflict of interest for this article. Ethical Statement Ethical approval was not required for this study because it was based on the analysis of existing, fully anonymized data. The study was conducted in accordance with the principles of the Declaration of Helsinki (as revised in Brazil 2013). Informed Consent not applicable Author Contribution N.T. and S.B. wrote the main manuscript text and prepared all figures. All authors reviewed the manuscript. Acknowledgement The authors thank the investigators who participated in this study: Iwate Prefectural Kamaishi Hospital (Kumagai H), Morioka Red Cross Hospital (Shimooki M). Thanks to Scribendi (www. scribendi.com) for English language editing. Data Availability All data supporting the findings of this study are available within the paper. References Ahn HS, Lee HJ, Yoo MW, et al. 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Feasibility and quality of life assessment of laparoscopic proximal gastrectomy using double-tract reconstruction. Langenbecks Arch Surg. 2021;406:479–489. Yamashita Y, Yamamoto A, Tamamori Y, Yoshii M, Nishiguchi Y. Side overlap esophagogastrostomy to prevent reflux after proximal gastrectomy. Gastric Cancer. 2017;20:728–735. Yamashita Y, Tatsubayashi T, Okumura K, Miyamoto T, Ueno K. Modified side overlap esophagogastrostomy after laparoscopic proximal gastrectomy. Ann Gastroenterol Surg. 2022;21:594–599. Kamikawa Y, Kobayashi T, Kamiyama S, et al. A new procedure of esophagogastrostomy to prevent reflux following proximal gastrectomy (in Japanese). Shoukakigeka. 2001;24:1053–1060. Shoji Y, Nunobe S, Ida S, et al. Surgical outcomes and risk assessment for anastomotic complications after laparoscopic proximal gastrectomy with double-flap technique for upper-third gastric cancer. Gastric Cancer. 2019;22:1036–1043. Nunobe S, Ida S. Current status of proximal gastrectomy for gastric and esophagogastric junctional cancer: a review. Ann Gastroenterol Surg. 2020;4:498–504. Uyama I, Suda K, Nakauchi M, et al. Clinical advantages of robotic gastrectomy for clinical stage I/II gastric cancer: a multi-institutional prospective single-arm study. Gastric Cancer. 2019;22:377–385. Shibasaki S, Suda K, Nakauchi M, et al. Robotic valvuloplastic esophagogastrostomy using double flap technique following proximal gastrectomy: technical aspects and short-term outcomes. Surg Endosc. 2017;31:4283–4297. Dindo D, Demartines N, Clavien PA. Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205-213. Hongo M. Minimal changes in reflux esophagitis: red ones and white ones. J Gastroenterol. 2006;41:95–99. Ignacio de Ulíbarri J, González-Madroño A, de Villar NG, et al. CONUT: a tool for controlling nutritional status. First validation in a hospital population. Nutr Hosp. 2005;20:38–45. Holloway RH. The anti-reflux barrier and mechanisms of gastro-oesophageal reflux. Baillieres Best Pract Res Clin Gastroenterol. 2000;14:681–699. Hill LD, Kozarek RA, Kraemer SJ, et al. The gastroesophageal flap valve: in vitro and in vivo observations. Gastrointest Endosc. 1996;44:541–547. Hosogi H, Sakaguchi M, Yagi D, et al. Side-overlap esophagogastric tube (SO-EG) reconstruction after minimally invasive Ivor Lewis esophagectomy or laparoscopic proximal gastrectomy for cancer of the esophagogastric junction. Langenbecks Arch Surg. 2022;407:861–869. Yamashita Y, Tatsubayashi T, Okumura K, et al. Modified side overlap esophagogastrostomy after laparoscopic proximal gastrectomy. Annals Gastroenterological Surg. 2022;6:594–599. Tanaka Y, Isobe T, Fujita F, Sudo T. The benefits of a double-flap technique after proximal gastrectomy in upper-third gastric cancer．Nippon Shokaki Geka Gakkai zasshi. 2019;52:494–503. Tables Table 1 and 2 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Tables1and2.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 03 Apr, 2026 Reviews received at journal 02 Apr, 2026 Reviews received at journal 29 Mar, 2026 Reviewers agreed at journal 24 Mar, 2026 Reviewers agreed at journal 23 Mar, 2026 Reviewers agreed at journal 20 Mar, 2026 Reviewers agreed at journal 18 Mar, 2026 Reviewers invited by journal 18 Mar, 2026 Editor assigned by journal 11 Jan, 2026 Submission checks completed at journal 09 Jan, 2026 First submitted to journal 05 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8520885","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":609692333,"identity":"7d5d252c-e286-472f-96c0-719cc2bc8fb1","order_by":0,"name":"Naoto Takahashi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYFACNjApxwYXOAAieHBr4IFqMQZSjA0kaUlsQNWCB9izH0v8XFBjk94nkfz8wQeGbXJ8B5gffmCQuYPbFp60w9IzjqXltkmkGTbOYLhtLHmAzViCgecZHoelN0jzsB3ObZNOMGzm/Xc7ccMBBjOg+GHcWvifN//m+Xc4nU06/WPzH4bb9RsOsH/Dr0Ui7Zg0b9vhBDbpHMNmBobbCQYHeAjYcuNZmjVvX5phm/ybwpk9DLcNZx7mKZZIwOMX9v4049s832zk5XuOb/jwg+G2PN/x9o0fPvbgDjEsgBmIE3sOkKIFDH6QrmUUjIJRMAqGLQAAKdpSxLy7OEYAAAAASUVORK5CYII=","orcid":"","institution":"Department of Surgery, Iwate Medical University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Naoto","middleName":"","lastName":"Takahashi","suffix":""},{"id":609692334,"identity":"caf33672-afdf-4674-af75-ce8c5469569d","order_by":1,"name":"Shigeaki Baba","email":"","orcid":"","institution":"Department of Surgery, Iwate Medical University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Shigeaki","middleName":"","lastName":"Baba","suffix":""},{"id":609692335,"identity":"5ecbcd61-4397-4ecb-baef-dc4e8aa4accc","order_by":2,"name":"Haruka Nikai","email":"","orcid":"","institution":"Department of Surgery, Iwate Medical University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Haruka","middleName":"","lastName":"Nikai","suffix":""},{"id":609692336,"identity":"1d37a3ae-ffc6-489c-a7fa-ddf269a2480f","order_by":3,"name":"Ryosuke Fujisawa","email":"","orcid":"","institution":"Department of Surgery, Iwate Medical University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Ryosuke","middleName":"","lastName":"Fujisawa","suffix":""},{"id":609692337,"identity":"a8b29986-e200-44d0-9b39-176dfe1a2672","order_by":4,"name":"Keisuke Koeda","email":"","orcid":"","institution":"Department of Medical Safety, Iwate Medical University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Keisuke","middleName":"","lastName":"Koeda","suffix":""},{"id":609692338,"identity":"001240b7-ff63-46bf-9b5a-0df81d04bc6f","order_by":5,"name":"Hiroyuki Nitta","email":"","orcid":"","institution":"Department of Surgery, Iwate Medical University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Hiroyuki","middleName":"","lastName":"Nitta","suffix":""},{"id":609692339,"identity":"d6f5987f-f410-4a94-a155-6832440a59ac","order_by":6,"name":"Akira Sasaki","email":"","orcid":"","institution":"Department of Surgery, Iwate Medical University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Akira","middleName":"","lastName":"Sasaki","suffix":""}],"badges":[],"createdAt":"2026-01-05 11:38:39","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8520885/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8520885/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105259469,"identity":"fe496ad3-9043-4c84-90cc-7d01a9711982","added_by":"auto","created_at":"2026-03-24 05:51:06","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":147121,"visible":true,"origin":"","legend":"\u003cp\u003ePort Placement for VEG-DFT.\u003c/p\u003e\n\u003cp\u003eGiven the characteristics of the surgical robotic system, the ports are arranged in a more horizontal line than in conventional laparoscopic proximal gastrectomy. The umbilical port is extended to create a mini-laparotomy for specimen extraction.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8520885/v1/7c6bb9b27b4d694305ce730f.png"},{"id":105259466,"identity":"6042f78d-bed1-4eec-afc6-2c57aaf3ac10","added_by":"auto","created_at":"2026-03-24 05:51:05","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2097368,"visible":true,"origin":"","legend":"\u003cp\u003eSurgical Procedure for DFT.\u003c/p\u003e\n\u003cp\u003e(A) After transecting the esophagus and extracting the resected stomach through umbilical mini-laparotomy, a seromuscular flap and an anastomotic opening are created on the remnant stomach extracorporeally. (B) The esophagus is mobilized to ensure a 5 cm anastomotic length, and the remnant stomach is fixed to the right and left diaphragmatic crura with single interrupted sutures. (C) The anterior wall of the remnant stomach and the posterior wall of the esophagus are fixed together at five points with interrupted sutures. (D) The esophageal lumen is opened, and the cranial side of the posterior wall of the esophagogastric anastomosis is sutured at full thickness. (E) The caudal side of the anterior wall of the esophagogastric anastomosis is sutured at full thickness to complete closure. (F) The seromuscular flap created on the remnant stomach is closed while fixedto the anterior wall of the esophagus.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8520885/v1/37f48b81276a4aadbcc7524c.png"},{"id":105259468,"identity":"694c7da5-a199-46ea-9f8f-59397bcae480","added_by":"auto","created_at":"2026-03-24 05:51:06","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1968066,"visible":true,"origin":"","legend":"\u003cp\u003ePre- and Postoperative Endoscopic Findings.\u003c/p\u003e\n\u003cp\u003eThis case involved a patient with a 0–IIa lesion on the posterior wall of the upper gastric body, identified preoperatively. VEG-DFT was performed. Upper gastrointestinal endoscopy postoperatively showed no evidence of reflux esophagitis while confirming the formation of a pseudo-fundus. The passage of contrast medium through the anastomosis was smooth, and no apparent reflux was observed, even in the supine position.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8520885/v1/561a340b94a6d21b1a92a40a.png"},{"id":105259467,"identity":"9cf735d8-40d4-4294-87fa-a743108f4a02","added_by":"auto","created_at":"2026-03-24 05:51:06","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":224143,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in Body Weight and Nutritional Status Before and After Surgery.\u003c/p\u003e\n\u003cp\u003eA significant difference was observed in the postoperative reduction rates of body weight and body mass index (BMI). However, no significant differences were found in the reduction rates of other blood-based nutritional parameters or the Controlling Nutritional Status (CONUT) score.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8520885/v1/4d31e86858ffe2ff9d7ac9e7.png"},{"id":105564737,"identity":"1373c782-6fc0-4701-99cb-2850b50ddc9c","added_by":"auto","created_at":"2026-03-27 12:50:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6257808,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8520885/v1/d6918497-c446-4b04-8863-f7e8f40e27ff.pdf"},{"id":105259465,"identity":"1c9806dc-d8fc-4296-87e4-b55d43e9523a","added_by":"auto","created_at":"2026-03-24 05:51:05","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":24590,"visible":true,"origin":"","legend":"","description":"","filename":"Tables1and2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8520885/v1/edf7520a3e97800fd65c76ef.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Short-Term Outcomes After the Introduction of Valvuloplastic Esophagogastrostomy via the Double-Flap Technique: Safe Robot-Assisted Implementation, Antireflux Efficacy, and Nutritional Impact","fulltext":[{"header":"Introduction","content":"\u003cp\u003eRecently, there has been a reported increase in the incidence of upper-third gastric and esophagogastric junction cancers [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], for which proximal gastrectomy (PG) has been recommended as a function-preserving surgical procedure [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Compared with total gastrectomy (TG), PG better maintains postoperative nutritional status and body weight [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, attention must be paid to anastomosis-related complications, such as anastomotic stricture and reflux esophagitis, which can lead to postoperative weight loss [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVarious reconstruction techniques have been developed for valvuloplastic esophagogastrostomy (VEG), including the double-tract method, jejunal interposition [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], the side-overlap (SO) method [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], and the Side Overlap with Fundoplication by Yamashita (SOFY) method [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Another, the double-flap technique (DFT) method was first described by Kamikawa et al. in 2001 [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Several studies have demonstrated the safety and low incidence of anastomotic complications when DFT in VEG [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, DFT is technically demanding due to the complexity of flap creation and suturing as well as the large number of sutures required. These factors contribute to prolonged operative time and increased procedural difficulty. Therefore, standardization and simplification of the technique are warranted.\u003c/p\u003e \u003cp\u003eRobot-assisted gastrectomy was approved for national insurance coverage in Japan in 2018, and multicenter prospective studies have shown its superiority in terms of minimal invasiveness compared with laparoscopic surgery [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Robotic surgery may offer advantages in performing DFT reconstruction due to its three-dimensional visualization and articulated instruments. Nevertheless, since DFT is performed entirely by hand-sewn sutures in both laparoscopic and robotic approaches, the absence of tactile feedback may lead to excessive suture tension, increasing the risk of tissue damage, impaired anastomotic blood flow, and stricture. Conversely, insufficient tension may result in anastomotic leakage or reflux esophagitis. Moreover, robotic surgery carries specific risks, such as inadvertent injury to surrounding tissues due to blind spots and operational errors during instrument exchange.\u003c/p\u003e \u003cp\u003eGiven these concerns, evaluating the safety of robotic VEG-DFT during its introductory phase is imperative, as evidence regarding its early adoption remains limited [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. At our institution, the SO method has been employed as a reconstruction technique for VEG in patients with early-stage upper gastric cancer. To further reduce postoperative reflux esophagitis, VEG-DFT was introduced in August 2023. In this study, we compare the short-term outcomes of patients who underwent SO and DFT following the introduction of VEG-DFT.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eSubjects and Indications\u003c/p\u003e\n\u003cp\u003eFrom January 2020 to February 2024, we enrolled 20 patients with early gastric cancer who had been diagnosed preoperatively with cT1bN0M0 Stage I disease according to the 15th edition of the Japanese Classification of Gastric Carcinoma. The indications for PG were as follows: (1) tumors localized to the upper third of the stomach, (2) tumor invasion limited to the muscularis propria, and (3) no evidence of lymph node metastasis on preoperative or intraoperative assessment. Surgical procedures, including the extent of lymph node dissection, were determined in accordance with the Japanese Gastric Cancer Treatment Guidelines, 7th edition [3]. We introduced the DFT procedure in October 2023 and applied it to all subsequent VEG cases. Patients treated up to September 2023 were classified into the SO group, whereas those treated from October 2023 onward were classified into the DFT group. All operations were performed by two board-certified gastrointestinal surgeons with more than 20 years of clinical experience. The da Vinci Surgical System Xi (Intuitive Surgical, USA) was used for all robot-assisted procedures. All patients were fully involved in the decision-making process, and written informed consent was obtained from each participant. This study was conducted with the approval of the Ethics Committee of Iwate Medical University (Approval No. MH2022-119).\u003c/p\u003e\n\u003cp\u003eSurgical Procedure\u003c/p\u003e\n\u003cp\u003eRobotic PG\u003c/p\u003e\n\u003cp\u003eRobotic PG was performed using a five-port configuration with a Nathanson liver retractor (Yufu Itonaga, Tokyo, Japan) (Figure 1). The robot was rolled in from the patient\u0026rsquo;s right side, and the third robotic arm was positioned on the patient\u0026rsquo;s left side to prioritize right-hand instrument control. The extent of lymph node dissection, were determined in accordance with the Japanese Gastric Cancer Treatment Guidelines, 7th edition [3]. After mobilization around the esophagogastric junction, the abdominal esophagus was transected via the assistant port using the Signia\u0026trade; stapling system with a 60-mm purple cartridge (Medtronic, Tokyo, Japan). The gastric body was subsequently divided using the same stapling system with two to three 60-mm purple cartridges.\u003c/p\u003e\n\u003cp\u003eVEG-DFT\u003c/p\u003e\n\u003cp\u003eIn the DFT group, VEG was performed as follows. After specimen extraction through a mini-laparotomy, a seromuscular flap (width 2.5 cm \u0026times; height 3.5 cm) was created on the remnant stomach outside the body cavity. An anastomotic opening measuring 2.5 cm was made at the lower edge of the flap (Figure 2A), and the anastomosis was completed intraperitoneally. The abdominal esophagus was mobilized approximately 5 cm longitudinally from the hiatus to secure adequate mobility from the gastric resection margin to the planned anastomotic site. The remnant stomach was anchored to the right and left diaphragmatic crura using 2-0 PDS\u0026reg; (Johnson \u0026amp; Johnson MedTech, Tokyo, Japan) (Figure 2B). Subsequently, five fixation sutures were placed between the posterior esophageal wall located 5 cm above the resection margin and the upper edge of the flap on the anterior wall of the remnant stomach using 3-0 Vicryl\u0026reg; (Johnson \u0026amp; Johnson MedTech, Tokyo, Japan) (Figure 2C). After fixation, the esophageal lumen was opened by cutting the staple line of the esophageal stump, and the cranial side of the anastomosis was sutured full-thickness with interrupted 3-0 Vicryl\u0026reg; stitches (Figure 2D). The caudal side was then similarly sutured full-thickness, followed by interrupted seromuscular\u0026ndash;adventitial sutures between the remnant stomach and esophagus to complete closure (Figure 2E). After the anastomotic closure, the bilateral seromuscular flaps created on the remnant stomach were approximated with interrupted sutures and secured anteriorly over the anastomosis (Figure 2F). Anastomotic patency and absence of air leakage were confirmed using intraoperative endoscopy.\u003c/p\u003e\n\u003cp\u003eVEG-SO\u003c/p\u003e\n\u003cp\u003eIn the SO group, VEG was performed as follows. After specimen extraction through a mini-laparotomy, a small enterotomy was created on the anterior wall of the remnant stomach approximately 5 cm distal to the gastric transection margin. Anastomosis was then completed intraperitoneally. A small opening was made on the left side of the esophageal stump, and the Signia\u0026trade; stapling system with a 60-mm purple cartridge was inserted and rotated 90\u0026deg; counterclockwise to create the anastomosis between the esophagus and the anterior gastric wall. The stapler entry hole was closed in a slit-like fashion using 4-0 V-Loc\u0026trade; (Covidien, Mansfield, USA) continuous Albert\u0026ndash;Lembert sutures. The esophagus was additionally fixed to the anterior wall of the remnant stomach with interrupted 3-0 Vicryl\u0026reg; sutures [7].\u003c/p\u003e\n\u003cp\u003ePostoperative Management\u003c/p\u003e\n\u003cp\u003ePostoperatively, patients resumed oral intake with an enteral formula on postoperative day (POD) 1. Based on a comprehensive assessment of laboratory findings and abdominal examinations, they were advanced to regular meals between POD 3 and 5. Regarding proton pump inhibitor (PPI) therapy, patients who had been taking PPIs preoperatively continued them after surgery. New PPI therapy was initiated in those who developed postoperative reflux symptoms\u0026mdash;such as heartburn, chest discomfort, or pain\u0026mdash;or in those diagnosed with Grade A or higher reflux esophagitis according to the revised Los Angeles classification on endoscopic examination at 6 months postoperatively. PPI therapy was discontinued at outpatient follow-up visits at 1, 3, 6, and 12 months after surgery if symptoms had resolved and endoscopic findings had improved.\u003c/p\u003e\n\u003cp\u003eDefinition of Complications\u003c/p\u003e\n\u003cp\u003eWe evaluated perioperative complications (Clavien\u0026ndash;Dindo classification [14], Grade II or higher), gastroesophageal reflux on upper gastrointestinal contrast studies at 1 month postoperatively, endoscopic findings at 6 months postoperatively (reflux esophagitis assessed according to the revised Los Angeles classification [15], and anastomotic stricture defined as the ability of a 10mm diameter endoscope tip to pass through the anastomosis), reflux-related symptoms associated with anastomotic stricture during the first postoperative year. For all patients, serum prealbumin levels were measured on postoperative day 7, regardless of the surgical technique. At the 6-month follow-up visit, total lymphocyte count (TLC) and serum albumin (Alb), cholinesterase (CHE), and total cholesterol (TC) levels were measured. The postoperative change rate in prealbumin was calculated based on preoperative values. For Alb and CHE, change rates at 6 months were also calculated relative to the preoperative baseline. Similarly, postoperative body weight loss at 6 months was calculated using preoperative weight as 100%. Controlling Nutritional Status (CONUT) scores [16] were calculated based on Alb, TC, and TLC and compared between preoperative and 6-month postoperative values. Continuous variables were presented as medians with ranges and compared using the Student\u0026rsquo;s t-test or Mann\u0026ndash;Whitney U test, as appropriate. Categorical variables were analyzed using the chi-square test or Fisher\u0026rsquo;s exact test when expected cell counts were insufficient. To complement hypothesis testing and avoid overinterpretation of non-significant results given the limited sample size, effect sizes for categorical outcomes were reported as odds ratios (ORs) with 95% confidence intervals. A two-sided P value \u0026lt;0.05 was considered statistically significant. All statistical analyses were performed using JMP\u0026reg; Pro version 13.0.0 (SAS Institute, Cary, NC, USA).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003ePatient Background\u003c/p\u003e\n\u003cp\u003eThe baseline characteristics of the SO and DFT groups are summarized in Table 1. Among the 24 patients who underwent robotic PG, 14 were classified into the SO group and 10 into the DFT group. There were no significant differences between the groups in terms of sex, body mass index (BMI), American Society of Anesthesiologists physical status (ASA-PS), preoperative tumor depth, pathological tumor depth, pathological lymph node metastasis, or postoperative stage. Although not statistically significant, body weight tended to be slightly lower in the DFT group (\u003cem\u003ep\u003c/em\u003e = 0.057). A significantly higher number of patients in the DFT group had a history of abdominal surgery (\u003cem\u003ep\u003c/em\u003e = 0.016).\u003c/p\u003e\n\u003cp\u003eSurgical Outcomes and Postoperative Complications\u003c/p\u003e\n\u003cp\u003eIn the DFT group, the median operative time was 361 minutes (range: 297\u0026ndash;426 minutes) and the median blood loss was 22.5 mL (range: 15.8\u0026ndash;37.0 mL). There were no significant differences between the SO and DFT groups in operative time, blood loss, or incidence of postoperative complications classified as Clavien\u0026ndash;Dindo grade II or higher (Table 2).\u003c/p\u003e\n\u003cp\u003eUpper gastrointestinal contrast studies showed no reflux of contrast into the esophagus in any patient, and the incidence of reflux esophagitis\u0026mdash;assessed using the modified Los Angeles classification\u0026mdash;was significantly lower in the DFT group (\u003cem\u003ep\u003c/em\u003e = 0.031) (Table2, Figure 3). No patients exhibited symptoms of stricture, and no obvious strictures were identified on contrast imaging.\u003c/p\u003e\n\u003cp\u003eBody Weight Changes and Nutritional Indicators\u003c/p\u003e\n\u003cp\u003eA significant decrease in body weight was observed in the DFT group compared with the SO group, even though the DFT group had a lower baseline body weight (\u003cem\u003ep\u003c/em\u003e = 0.034). No significant differences were observed between the two groups in any of the blood-based nutritional parameters (Figure 4).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe primary aim of this study was to evaluate the safety and short-term oncologic, functional, and nutritional outcomes of robot-assisted VEG-DFT during its introductory phase, and to compare these outcomes with those of the conventional SO method. In particular, we sought to determine whether the adoption of VEG-DFT could reduce postoperative reflux while maintaining acceptable operative safety and nutritional preservation. This study demonstrated that the introduction of robotic VEG-DFT was feasible and safe, with no significant differences from the SO method in operative time, blood loss, or the incidence of Clavien\u0026ndash;Dindo grade II or higher complications. Importantly, postoperative upper gastrointestinal contrast studies revealed no reflux in either group, but endoscopic assessment showed a significantly lower incidence of reflux esophagitis in the DFT group. No anastomotic strictures or stricture-related symptoms occurred in either cohort. Although patients in the DFT group experienced greater postoperative weight loss despite having a lower baseline body weight, no significant differences were observed in blood-based nutritional parameters\u0026mdash;including Alb, CHE, TC, TLC, or prealbumin\u0026mdash;at 6 months postoperatively.\u003c/p\u003e \u003cp\u003eReflux esophagitis after PG is primarily associated with disruption of the physiological anti-reflux mechanism, particularly loss of lower esophageal sphincter (LES) function and the angle of His. This anti-reflux barrier comprises the LES, angle of His, diaphragmatic crura, and phrenoesophageal ligament [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The LES functions as a high-pressure zone at the distal esophagus, while the angle of His contributes to a flap\u0026ndash;valve mechanism at the esophagogastric junction. Hill et al. demonstrated that a well-formed flap valve observed endoscopically is associated with a lower risk of reflux esophagitis [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Following surgery for upper gastric or esophagogastric junction cancer, these anatomical structures are often disrupted. Therefore, reconstruction techniques that restore these anti-reflux mechanisms are essential after PG. At our institution, the SO method had been used as the standard reconstruction following proximal gastrectomy. This technique creates an artificial valve by suturing the esophagus to the gastric wall, reconstructing the angle of His and a pseudo-fundus to prevent reflux through compression of the lower esophagus during increases in intragastric pressure [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, postoperative reflux symptoms and esophagitis still occurred in some patients, suggesting that the anti-reflux effect of the SO method may be insufficient in certain cases. To address this limitation, we introduced the DFT as an alternative anti-reflux reconstruction. In the present study, the DFT group showed a significantly lower incidence of postoperative reflux esophagitis than the SO group, with no cases of grade A or higher esophagitis according to the modified Los Angeles classification. Endoscopic findings at 6 months postoperatively demonstrated formation of a pseudo-fundus in the remnant stomach, indicating a favorable anastomotic configuration. Notably, no anastomosis-related complications, including leakage or postoperative abscess, were observed in the DFT group. Importantly, performing DFT under robot-assisted surgery allows for precise flap creation and meticulous suturing using articulated instruments and three-dimensional visualization, enabling accurate reconstruction of the anti-reflux mechanism while minimizing tissue trauma. This technical advantage facilitates functional preservation with minimal invasiveness. As previously described by Tanaka et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], DFT embeds the distal esophagus within the submucosal layer of the remnant stomach, where it is compressed by intragastric pressure and the seromuscular flap, functioning as a valve. In addition, coverage of the anterior anastomotic wall by the seromuscular flap may contribute to the low risk of anastomotic leakage. In our series, DFT was introduced safely without significantly increasing operative time, blood loss, postoperative complications, or length of hospital stay compared with the SO method, and reconstruction time was comparable between the two techniques.\u003c/p\u003e \u003cp\u003eAlthough blood-based nutritional parameters did not significantly deteriorate in the DFT group, postoperative weight loss was more pronounced. This discrepancy may be explained by several factors. First, while DFT effectively prevents reflux, the flap structure at the anastomosis may alter food passage, potentially leading to early satiety or postprandial discomfort and reduced oral intake, even in the absence of evident stricture or reflux. However, mechanical resistance and subjective symptoms were not evaluated in this study, and this interpretation remains speculative. Second, blood-based nutritional markers primarily reflect short-term protein metabolism and immune status and may not adequately capture chronic nutritional deficits such as reduced caloric intake or sarcopenia. Consequently, loss of lean body mass may have progressed without detectable changes in laboratory parameters. In addition, patients in the DFT group tended to have lower preoperative body weight and had a significantly higher prevalence of prior abdominal surgery, which may have influenced baseline digestive and absorptive capacity. Future studies should incorporate detailed dietary assessments, gastrointestinal functional evaluation, and body composition analysis to better clarify the mechanisms underlying postoperative weight loss.\u003c/p\u003e \u003cp\u003eThis study has several limitations. It was conducted at a single institution using a retrospective design and did not include patient-reported outcomes or quality-of-life assessments based on validated questionnaires. Although the present results confirm the feasibility and safety of introducing the DFT in a robot-assisted setting, the sample size remains insufficient for robust multivariable analysis. In addition, this was not a randomized study, and long-term follow-up has not yet been completed. These limitations may affect the generalizability of our findings.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eConflict of Interest\u003c/h2\u003e\n\u003cp\u003eThe authors declare no conflict of interest for this article.\u003c/p\u003e\n\u003ch2\u003eEthical Statement\u003c/h2\u003e\n\u003cp\u003eEthical approval\u0026nbsp;was not required for this study because it was based on the analysis of existing, fully anonymized data. The study was conducted in accordance with the principles of the Declaration of Helsinki (as revised in Brazil 2013).\u003c/p\u003e\n\u003ch2\u003eInformed Consent\u003c/h2\u003e\n\u003cp\u003enot applicable\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eN.T. and S.B. wrote the main manuscript text and prepared all figures. All authors reviewed the manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgement\u003c/h2\u003e\n\u003cp\u003eThe authors thank the investigators who participated in this study: Iwate Prefectural Kamaishi Hospital (Kumagai H), Morioka Red Cross Hospital (Shimooki M). Thanks to Scribendi (www. scribendi.com) for English language editing.\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eAll data supporting the findings of this study are available within the paper.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAhn HS, Lee HJ, Yoo MW, et al. Changes in clinicopathological features and survival after gastrectomy for gastric cancer over a 20-year period. Br J Surg. 2011;98:255\u0026ndash;260.\u003c/li\u003e\n \u003cli\u003eKusano C, Gotoda T, Khor CJ, et al. Changing trends in the proportion of adenocarcinoma of the esophagogastric junction in a large tertiary referral center in Japan. J Gastroenterol Hepatol. 2008;23:1662\u0026ndash;1665.\u003c/li\u003e\n \u003cli\u003eJapanese Gastric Cancer Association. Japanese gastric cancer treatment guidelines 2025 (7th ed.). Tokyo: KANEHARA \u0026amp; CO., LTD.; 2025.16\u0026ndash;25p.\u003c/li\u003e\n \u003cli\u003eHayami M, Hiki N, Nunobe S, et al. Clinical outcomes and evaluation of laparoscopic proximal gastrectomy with double-flap technique for early gastric cancer in the upper third of the stomach. Ann Surg Oncol. 2017;24:1635\u0026ndash;1642.\u003c/li\u003e\n \u003cli\u003eKano Y, Ohashi M, Nunobe S. Laparoscopic function-preserving gastrectomy for proximal gastric cancer or esophagogastric junction cancer: a narrative review. Cancers (Basel). 2023;15:311.\u003c/li\u003e\n \u003cli\u003eSato R, Kinoshita T, Akimoto E, Yoshida M, Nishiguchi Y, Harada J. Feasibility and quality of life assessment of laparoscopic proximal gastrectomy using double-tract reconstruction. Langenbecks Arch Surg. 2021;406:479\u0026ndash;489.\u003c/li\u003e\n \u003cli\u003eYamashita Y, Yamamoto A, Tamamori Y, Yoshii M, Nishiguchi Y. Side overlap esophagogastrostomy to prevent reflux after proximal gastrectomy. Gastric Cancer. 2017;20:728\u0026ndash;735.\u003c/li\u003e\n \u003cli\u003eYamashita Y, Tatsubayashi T, Okumura K, Miyamoto T, Ueno K. Modified side overlap esophagogastrostomy after laparoscopic proximal gastrectomy. Ann Gastroenterol Surg. 2022;21:594\u0026ndash;599.\u003c/li\u003e\n \u003cli\u003eKamikawa Y, Kobayashi T, Kamiyama S, et al. A new procedure of esophagogastrostomy to prevent reflux following proximal gastrectomy (in Japanese). Shoukakigeka. 2001;24:1053\u0026ndash;1060.\u003c/li\u003e\n \u003cli\u003eShoji Y, Nunobe S, Ida S, et al. Surgical outcomes and risk assessment for anastomotic complications after laparoscopic proximal gastrectomy with double-flap technique for upper-third gastric cancer. Gastric Cancer. 2019;22:1036\u0026ndash;1043.\u003c/li\u003e\n \u003cli\u003eNunobe S, Ida S. Current status of proximal gastrectomy for gastric and esophagogastric junctional cancer: a review. Ann Gastroenterol Surg. 2020;4:498\u0026ndash;504.\u003c/li\u003e\n \u003cli\u003eUyama I, Suda K, Nakauchi M, et al. Clinical advantages of robotic gastrectomy for clinical stage I/II gastric cancer: a multi-institutional prospective single-arm study. Gastric Cancer. 2019;22:377\u0026ndash;385.\u003c/li\u003e\n \u003cli\u003eShibasaki S, Suda K, Nakauchi M, et al. Robotic valvuloplastic esophagogastrostomy using double flap technique following proximal gastrectomy: technical aspects and short-term outcomes. Surg Endosc. 2017;31:4283\u0026ndash;4297.\u003c/li\u003e\n \u003cli\u003eDindo D, Demartines N, Clavien PA. Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205-213.\u003c/li\u003e\n \u003cli\u003eHongo M. Minimal changes in reflux esophagitis: red ones and white ones. J Gastroenterol. 2006;41:95\u0026ndash;99.\u003c/li\u003e\n \u003cli\u003eIgnacio de Ul\u0026iacute;barri J, Gonz\u0026aacute;lez-Madro\u0026ntilde;o A, de Villar NG, et al. CONUT: a tool for controlling nutritional status. First validation in a hospital population. Nutr Hosp. 2005;20:38\u0026ndash;45.\u003c/li\u003e\n \u003cli\u003eHolloway RH. The anti-reflux barrier and mechanisms of gastro-oesophageal reflux. Baillieres Best Pract Res Clin Gastroenterol. 2000;14:681\u0026ndash;699.\u003c/li\u003e\n \u003cli\u003eHill LD, Kozarek RA, Kraemer SJ, et al. The gastroesophageal flap valve: in vitro and in vivo observations. Gastrointest Endosc. 1996;44:541\u0026ndash;547.\u003c/li\u003e\n \u003cli\u003eHosogi H, Sakaguchi M, Yagi D, et al. Side-overlap esophagogastric tube (SO-EG) reconstruction after minimally invasive Ivor Lewis esophagectomy or laparoscopic proximal gastrectomy for cancer of the esophagogastric junction. Langenbecks Arch Surg. 2022;407:861\u0026ndash;869.\u003c/li\u003e\n \u003cli\u003eYamashita Y, Tatsubayashi T, Okumura K, et al. Modified side overlap esophagogastrostomy after laparoscopic proximal gastrectomy. Annals Gastroenterological Surg. 2022;6:594\u0026ndash;599.\u003c/li\u003e\n \u003cli\u003eTanaka Y, Isobe T, Fujita F, Sudo T. The benefits of a double-flap technique after proximal gastrectomy in upper-third gastric cancer．Nippon Shokaki Geka Gakkai zasshi. 2019;52:494\u0026ndash;503.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 and 2 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"langenbecks-archives-of-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"laos","sideBox":"Learn more about [Langenbeck's Archives of Surgery](http://link.springer.com/journal/423)","snPcode":"423","submissionUrl":"https://submission.nature.com/new-submission/423/3","title":"Langenbeck's Archives of Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-8520885/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8520885/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e \u003cp\u003eProximal gastrectomy (PG) has recently gained attention as a minimally invasive surgical option and a function-preserving surgery for early gastric cancer in the upper stomach. Among the various reconstruction methods following proximal gastrectomy, the double-flap technique (DFT) has been reported to provide effective anti-reflux function. In this study, we introduced the valvuloplastic esophagogastrostomy by double flap technique (VEG-DFT) and retrospectively compared its short-term outcomes with those of the conventional side-overlap (SO) method.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA total of 24 patients with cT1bN0M0 early gastric cancer located in the upper third of the stomach underwent VEG at our institution between January 2020 and July 2024. Of these, 14 underwent VEG-SO (SO group), and 10 underwent VEG-DFT (DFT group).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eOperative time, intraoperative blood loss, and the incidence of perioperative complications (Clavien\u0026ndash;Dindo grade\u0026thinsp;\u0026ge;\u0026thinsp;II) were comparable between the two groups. Postoperative upper gastrointestinal contrast studies and endoscopy revealed a significantly lower incidence of gastroesophageal reflux disease in the DFT group. No cases of anastomotic stenosis or leakage were observed in either group. Although serum nutritional indicators\u0026mdash;including albumin and prealbumin\u0026mdash;showed no significant differences between groups at six months postoperatively, body weight loss was significantly greater in the DFT group.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eDFT may influence postoperative eating behavior, potentially due to increased passage resistance or early satiety. VEG-DFT was safely introduced and demonstrated favorable reflux control.\u003c/p\u003e","manuscriptTitle":"Short-Term Outcomes After the Introduction of Valvuloplastic Esophagogastrostomy via the Double-Flap Technique: Safe Robot-Assisted Implementation, Antireflux Efficacy, and Nutritional Impact","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-24 05:51:01","doi":"10.21203/rs.3.rs-8520885/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-03T17:16:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-02T17:15:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-29T04:09:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"48172169968496008285678325780999250799","date":"2026-03-24T15:59:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"179028969348498234423300281780707637018","date":"2026-03-23T13:24:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"101551617994267341513596289458996738677","date":"2026-03-21T00:00:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"333737144750237793626097983412430737541","date":"2026-03-18T13:05:49+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-18T12:38:25+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-11T06:00:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-09T09:34:12+00:00","index":"","fulltext":""},{"type":"submitted","content":"Langenbeck's Archives of Surgery","date":"2026-01-05T11:28:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"langenbecks-archives-of-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"laos","sideBox":"Learn more about [Langenbeck's Archives of Surgery](http://link.springer.com/journal/423)","snPcode":"423","submissionUrl":"https://submission.nature.com/new-submission/423/3","title":"Langenbeck's Archives of Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f0363e25-4bde-48ef-bff1-eb2d028fbf3a","owner":[],"postedDate":"March 24th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-24T05:51:01+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-24 05:51:01","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8520885","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8520885","identity":"rs-8520885","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}