Validation of Padova Classification of Post-Fundoplication Outflow Obstruction on High-Resolution Manometry in an International Multi-Center Study.

BACKGROUND: Dysphagia after laparoscopic Nissen fundoplication (LNF) is common and may be due to post-fundoplication outflow obstruction (PFOO) as defined by high-resolution manometry (HRM) using the Padova Classification. This study aimed to compare clinical and HRM parameters between patients with manometric PFOO and those with a functioning, effective fundoplication (FELF), and to evaluate treatment outcomes in PFOO patients. METHODS: This retrospective study from two international centers included patients who underwent LNF and postoperative HRM between January 2000 and January 2025. Patients were categorized into PFOO (manometric PFOO) and FELF (manometric FELF and normal reflux study) groups. HRM parameters including LES basal pressure, integrated relaxation pressure (IRP), and esophageal body function were compared. Postoperative dysphagia was assessed clinically, and treatment outcomes in PFOO patients were evaluated. RESULTS: Among 106 patients (62 PFOO, 44 FELF), the PFOO group showed significantly higher median LES basal pressure (41.2 vs. 23.7 mmHg, p < 0.01), IRP (19.3 vs. 10.3 mmHg, p < 0.01), and LES lengths (p = 0.01). PFOO patients had an increased incidence of elevated intrabolus pressure and premature swallows (p < 0.01). Dysphagia was reported in 89% of PFOO patients versus 5% in FELF (p < 0.01). Of symptomatic PFOO patients undergoing retreatment (pneumatic dilation, redo surgery, or both), 89% achieved symptom improvement. CONCLUSIONS: This first study applying the Padova Classification confirms HRM can distinguish obstructive from functional fundoplications post-LNF, supporting its diagnostic role in managing postoperative dysphagia.