A flow visualization model of duodenogastric reflux after esophagectomy with gastric interposition

Abstract

Background: Our goal was to verify surgical factors that affect duodenogastric reflux (DGR) after esophagectomy through the use of a flow visualization model that would mimic an intrathoracic gastric tube.

Methods: Transparent gastric tube models for different routes (retrosternal space [RS] and posterior mediastinum [PM]) were fabricated. Various distal pressures were applied to the experimental model filled with water, and the flow was recorded with a high-speed camera. The volume and maximum height of the refluxate through the pylori of two different sizes (7.5 mm, 15 mm) in two different postures (upright, semi-Fowler) was measured by analyzing the video clips.

Results: For the large pylorus setting, when the pressures of 20, 30, and 40 mmHg were applied in the upright position, the volumes of the refluxate in the RS/PM tubes were 87.7 ± 1.1/96.4 ± 1.7 mL, 150.8 ± 1.1/158.0 ± 3.2 mL, and 156.8 ± 3.3/198.0 ± 4.7 mL (p < 0.05), and the maximum heights were 101.6 ± 4.8/113.4 ± 2.9 mm, 151.4 ± 2.2/165.4 ± 1.5 mm, and 166.1 ± 1.7/193.7 ± 6.6 mm (p < 0.05). The data for the small pylorus setting or in the semi-Fowler position showed similar tendencies. For any given route, posture or pressure setting, DGR in the large pylorus model was definitively higher than that for small one.

Conclusions: This fluid mechanics study demonstrates posterior mediastinal gastric interposition or pyloric drainage procedure, or both, is associated with high reflux of duodenal contents.

Figure 1

Averaging the course of the gastric tube. Bold lines represent the average of centroids (x, y) of 5 gastric tubes according to the vertical position (z) in each route. A, x in the retrosternal route. B, y in the retrosternal route. C, Retrosternal gastric tube model. D, x in the posterior mediastinal route. E, y in the posterior mediastinal route. F, Posterior mediastinal gastric tube model.

Figure 2

Experimental setup for measuring reflux.

Figure 3

Gastric tube model in the semi-Fowler position. A, Retrosternal route. B, Posterior mediastinal route. h, Maximum height of refluxate; A, Anterior; Ca, Caudal; Cr, Cranial; P, Posterior.