Background: The pathophysiological and clinical value of performing High-Resolution Manometry (HRM) after laparoscopic fundoplication (LF) for gastroesophageal reflux disease (GERD) is still unclear and debated. Objective: We sought to establish the HRM parameters indicative of functioning fundoplications, and whether HRM could distinguish them from tight or defective ones. Methods: The study involved patients with GERD who underwent laparoscopic Nissen (LN) or Toupet (LT) fundoplication between 2010 and 2022. HRM and 24-h pH monitoring were performed before and 6 months after surgery. The study population was divided into 5 groups: LN and LT patients with normal 24h-pH findings (LNpH- and LTpH-, respectively); LN and LT patients with pathological 24h-pH findings (LNpH+ and LTpH + groups, respectively); and patients with a postoperative dysphagia intensity score >2 (Dysphagia group). The novel Hiatal Morphology (HM) classification was applied, envisaging 3 different subtypes: HM1 (normal), HM2 (intrathoracic fundoplication), and HM3 (slipped fundoplication). Results: Among the 132 patients recruited during the study period, 46 were in the LNpH- group, 51 in the LTpH- group, 15 in the LNpH + group, 7 in the LTpH + group, and 5 in the Dysphagia group. In multivariate analysis, postoperative abdominal lower esophageal sphincter length (p = 0.001) and HM2 (p < 0.001) were both independently associated with surgical failure. Integrated relaxation pressure was significantly higher in the Dysphagia group than in the LNpH- group. Conclusion: This study generated reference HRM values for an effective LF, and confirms that using HRM to assess the neo-sphincter and HM improves the clinical assessment in cases of symptom recurrence.
