A flow visualization model of gastric emptying in the intrathoracic stomach after esophagectomy

Background: Our goal was to verify surgical factors that affect gastric emptying after esophagectomy through the use of a flow visualization model to mimic an intrathoracic gastric tube. Methods: The route and length of the gastric tube model was determined from postoperative computed tomography (CT) images of 5 patients who underwent esophagectomy with gastric interposition. Transparent tubes of various sizes (20, 40 and 60 mm in diameter) were fabricated cylindrically for comparison. 200 mL of liquid with a different viscosity were poured through the gastric tube, and the flow was recorded with a high-speed camera. Transit time to pass the pylori of different sizes (7.5 and 15 mm in diameter) was measured by analyzing the video clips. Results: For the small pylorus setting, emptying times in the 20-, 40-, and 60-mm tubes were 3.17 ± 0.07, 6.55 ± 0.28, and 7.60 ± 0.69 seconds for water (p < 0.000), and 15.56 ± 0.55, 19.75 ± 0.47, and 23.28 ± 0.32 seconds for glycerine (p < 0.000). For the large pylorus setting, emptying times were 2.66 ± 0.10, 2.93 ± 0.05, and 3.37 ± 0.10 seconds for water (p < 0.000) and 9.95 ± 0.18, 11.18 ± 0.33, and 10.95 ± 0.16 seconds for glycerin (p < 0.000). For any given tube size and liquid setting, emptying times for the small pylorus model were always significantly longer than those for the large one (p < 0.000). Conclusions: This fluid mechanics study demonstrates a narrow gastric tube or pyloric drainage procedure, or both, improves gastric emptying. This finding may help reduce the incidence of delayed gastric emptying after esophagectomy with gastric interposition.