Background: Laparoscopic Nissen fundoplication effectively reduces acid reflux and reflux symptoms. Little is known about the effect on reflux mechanisms, especially on transient lower oesophageal sphincter relaxations (TLOSRs).
Methods: Twenty-seven patients were studied prospectively before and after laparoscopic Nissen fundoplication, by simultaneous recording of pH and lower oesophageal sphincter (LOS) characteristics using sleeve manometry. In all of the 27 patients the operation was judged successful, based on major improvement or resolution of reflux symptoms and acid reflux. Vagus nerve integrity was studied indirectly by the secretion of pancreatic polypeptide (PP) in response to insulin-induced hypoglycaemia.
Results: After fundoplication basal LOS pressure increased significantly from mean(s.e.m.) 13(1) to 22(1) mmHg (P < 0.001). Laparoscopic Nissen fundoplication significantly decreased the frequency of TLOSR in the fasting period from mean(s.e.m.) 2.5(0.5) to 0.6(0.2) per h, and in the postprandial period from 4.0(0.4) to 1.3(0.3) per h (P < 0.01). The percentage of TLOSRs associated with reflux also decreased significantly from 24(10) to 0(0) per cent in the fasting period and from 42(6) to 12(6) per cent in the postprandial period, before and after fundoplication respectively (P < 0.01). After operation the PP response was abnormal in three patients, pointing to vagus nerve dysfunction. Postoperative TLOSR frequency and LOS pressure were no different between patients with and without vagus nerve dysfunction.
Conclusion: Laparoscopic Nissen fundoplication significantly increased fasting and postprandial LOS pressure and significantly decreased the rate of TLOSR. This resulted in a significant reduction in oesophageal acid exposure but postprandial LOS characteristics were preserved.