The "floppy" Nissen fundoplication is a completely competent antireflux valve

Background: The antireflux capacity of various gastric fundoplications comb ines the creation of a valve (flapper or nipple) with recreation of a sharp cardioesophageal angle. Experimental comparison of valve competency and ap propriate valve geometry is incomplete despite wide application of these te chniques. Our primary aim was to compare the competency of several antirefl ux valves in explanted cadaver stomachs. Our secondary aim was to understan d better the geometry of the gastric fundus in empty and full stomachs. Methods: Stomachs with 6-8 cm of distal esophagus were harvested from 18 fr esh cadavers. With the stomach empty, the greater and lesser curvature leng th and the transverse dimensions of the anterior and posterior surface of t he stomach in the fundus, body, and antrum were measured. The pylorus was t ied off over a catheter; the stomachs were inflated with water; and reflux occurred. Intragastric pressure was measured during inflation with a needle inserted in the side of the stomach. A clamp was then placed on the esopha gus, and the stomach was inflated to a pressure of 10 mmHg. Gastric measure ments were recalculated in the distended stomach. The stomachs were deflate d, the clamp removed, and a 2-cm Nissen fundoplication as well as 270 degre es and 180 degrees posterior fundoplications were performed over a 60 Fr di lator. The stomachs were reinflated while the pressure was transduced. The inflation was stopped when reflux occurred or when the fundoplication disru pted. Results: The stomachs expanded symmetrically when filled with water except for the fundus in which the anterior gastric wall lengthened by more than 1 00% and the posterior gastric wall lengthened by about 50%. In the untreate d stomachs, reflux occurred at a pressure of 3.0 +/- 1.0 mmHg. After fundop lication, reflux never occurred, but the sutures pulled out of the stomach or esophagus at 28.6 +/- 16.8 mmHg. Posterior fundoplications refluxed wate r in several stomachs. Conclusions: When filled, the anterior fundus expands to a greater degree t han the posterior fundus, offering more tissue for creation of floppy fundo plication. The "floppy" Nissen fundoplication is completely competent, suff ering a degradation before allowing reflux. The posterior partial fundoplic ation is unpredictable in its competency.