ENDOSCOPIC CLASSIFICATION OF FUNDOPLICATION INTEGRITY PREDICTS PATHOLOGIC REFLUX

Background and Rationale Gastroesophageal reflux disease (GERD) is highly prevalent. Although medical therapy is first-line treatment, a significant proportion of patients have incomplete symptom control or require long-term medication. Anti-reflux surgery (ARS), primarily laparoscopic Nissen or Toupet fundoplication, re-establishes the anti-reflux barrier by recreating the gastroesophageal valve and repairing the hiatal defect. Endoscopy is the most common and often the only test performed after ARS. However, existing endoscopic classifications are complex, poorly standardized, and have never been validated against objective functional testing (HRM and reflux monitoring). This study was designed to identify which endoscopic parameters truly correlate with pathologic reflux and to create a simple, clinically meaningful classification.Study Design Single-center, two-phase cohort study. Development phase (retrospective, April 2018 - April 2024): classification was built.

Validation phase (prospective, May 2024 - April 2026): independent validation of the classification.

Inclusion Criteria Adults (18-90 years) who underwent Nissen or Toupet fundoplication for GERD or large hiatal hernia Completion of post-operative esophagogastroduodenoscopy (EGD) with adequate retroflexed videoclip, high-resolution manometry (HRM), and reflux monitoring (MII-pH or wireless pH) Both primary and redo procedures included

Exclusion Criteria Other foregut operations (Dor, Collis, magnetic sphincter augmentation, bariatric surgery) Insufficient quality of endoscopic videoclips Missing HRM or reflux monitoring

Endpoints Primary endpoint: Association between the new endoscopic classification (number of impaired mechanisms: 0-3) and pathologic GERD according to Lyon 2.0 criteria. Secondary endpoints: Correlation with individual symptoms and validated questionnaires (GERD-Q, GERD-HRQL, RSI, FOSS) Correlation with HRM parameters (LES pressure/length, EGJ-CI, Padova Consensus criteria for disruption/herniation, SLR maneuver) Correlation with reflux monitoring parameters (AET, MNBI, reflux episodes, symptom-reflux association)

Endoscopic Assessment All retroflexed videoclips were reviewed blinded to clinical and functional data by an experienced foregut surgeon. The following parameters were evaluated: Valve location: intra-abdominal vs intrathoracic (relative to diaphragmatic crura) Valve integrity: depth of anterior and posterior grooves (0-2 each). Groove sum <2 = disrupted valve Hiatal opening: visible (separated crura) vs not visible Valve lip thickness: thick vs thin (exploratory) Presence of para-esophageal hernia

Definition of Pathologic GERD (Lyon 2.0) AET >6%, or AET 4-6% + at least one adjunctive criterion (MNBI <1500 Ω, positive SI/SAP, >80 reflux episodes), or De novo Barrett's esophagus or LA grade B-D esophagitis

Statistical Analysis Continuous variables expressed as median [IQR], compared with Mann-Whitney or Kruskal-Wallis tests. Categorical variables compared with χ² or Fisher exact test. Odds ratios for association with pathologic GERD. ROC curves and AUC for discriminatory capacity of the classification. DeLong test for comparison of ROC curves.