Excessive competence of the lower oesophageal sphincter after Nissen fundoplication: evaluation by three-dimensional computerised imaging.

OBJECTIVE

To compare the competence of the lower oesophageal sphincter after Nissen fundoplication with that in a control group of healthy volunteers using a new computerized manometric device that integrates the pressure and length of the entire sphincter into one measurement, called the vector volume.

DESIGN

Open study.

SETTING

University hospital, Italy.

SUBJECTS

18 patients, 6-52 months (mean 10 months) after they had undergone Nissen fundoplication for gastro-oesophageal reflux, and 14 healthy volunteers.

INTERVENTIONS

Oesophageal computerised manometric system comprising a catheter with eight side holes radially oriented to each other at 45 degrees on one level and 24-hour oesophageal pH monitoring.

MAIN OUTCOME MEASURES

Differences in percentage time of oesophageal acid exposure, number of episodes of gastro-oesophageal reflux, and lower oesophageal sphincter vector volume.

RESULTS

The pH of the oesophagus was returned to the normal range in all patients after the Nissen fundoplication. There was a significant reduction in both the percentage time of acid exposure and the number of episodes of gastro-oesophageal reflux compared with the control group (p < 0.001). The vector volume of the intra-abdominal part of the lower oesophageal sphincter was significantly increased compared with the control group (p < 0.04). Lower oesophageal sphincter pressure measured at the respiratory inversion point, and lower oesophageal length, both increased after fundoplication to become similar to control values. When sphincter pressure was measured as a mean of the sphincter pressure curve there was a clear difference postoperatively compared with controls (p < 0.02).

CONCLUSIONS

Nissen fundoplication corrects abnormal gastro-oesophageal reflux but abolishes normal physiological postprandial reflux; this is caused by the gastric fundus that encircling the intra-abdominal oesophagus, restores sphincter pressure and length, and modifies its shape.