Fundoplications resist reflux independent of in vivo anatomic relationships

BACKGROUND: Antireflux operations restore lower esophageal sphincter (LES) function and hiatal anatomy; however, the relative contributions are unclear. METHODS: We measured the competency of fundoplications, exclusive of in vivo variables, in gastroesophageal explants from 8 cadavers. Using a multichannel manometer, esophageal, LES, and intragastric pressures were recorded during transpyloric distension. Data were corn pared at baseline, and after Nissen (360°) and Toupet (270°) fundoplications. RESULTS: Before fundoplication, stomachs refluxed immediately upon distension. Nissen fundoplications never refluxed before gastric rupture (46.8 ± 15.0 mm Hg). LES pressure averaged 2.0 ± 0.5 times intragastric pressure during distension. Toupet fundoplications refluxed at intragastric pressure <2 mm Hg, then became competent until gastric rupture (49.9 ± 15.0 mm Hg). LES pressure averaged 2.4 ± 1.0 times intragastric pressure during distension. CONCLUSIONS: Nissen and Toupet fundoplications increase LES pressure linearly at 2 to 2.5 times intragastric pressure, independent of in vivo variables. Toupet fundoplication lacks the competency of Nissen fundoplication at low intragastric pressures.