Manometric study of the effects of experimental fundoplication in rats.

BACKGROUND

The manometric effects of surgical repair of gastroesophageal reflux remain largely unknown, making the interpretation of the changes in the esophagogastric high pressure zone after fundoplication difficult.

AIM

To measure in a murine model the transdiaphragmatic pressure gradients, intraabdominal esophageal length, and lower esophageal sphincter pressure and length after Nissen fundoplication.

MATERIAL AND METHODS

Adult Wistar rats were divided into two groups Control group (n = 10): in which measurements were made after laparotomy and intraabdominal esophageal dissection. Nissen Group (n = 15): in which measurements were made at baseline, after fundoplication and 1 week after surgery. We considered the following variables: end-inspiratory and end-expiratory transdiaphragmatic gradient (TDIG and TDEG respectively), lower esophageal sphincter pressure (LESP) length (LESL), and length of the intraabdominal segment of the esophagus (LIAS).

RESULTS

The LIAS increased significantly after esophagogastric dissection in the control group (11.38 +/- 3.22 mm vs 16.02 +/- mm, p < 0.05). No differences between pre- and postoperative status were found in TDIG, TDEG, LESP and LESL in the control group. However, LESP increased significantly after fundoplication (14.22 +/- 13.3 vs 32.96 +/- 7.8 mmHg, p < 0.05) and these differences were still present one week later (30.72 +/- 6.73 mmHg, p < 0.05). LESL was also increased (1.91 +/- 1.76 mm vs 7.68 +/- 1.83 mm) after fundoplication (p < 0.05), and reached 7.02 +/- 2.18 mm (p < 0.05) 1 week later. No differences were found in pre- and postoperative TDIG, TDEG and LIAS in the Nissen Group.

CONCLUSION

In this murine experimental model, intraabdominal esophageal dissection increased the length of the intraabdominal esophagus without modifying the esophagogastric high pressure zone, while Nissen fundoplication increased lower esophageal sphincter pressure and length, without modifying the length of the intraabdominal esophagus or the transdiaphragmatic pressure gradients.