Evaluation of vagus nerve function before and after antireflux surgery

We sought to evaluate vagus nerve integrity before and after antireflux surgery and to compare it with symptomatic outcome. Antireflux surgery patients were recruited. Patients with disorders associated with vagus dysfunction or who took medications with anticholinergic effects were excluded. Each patient underwent a sham-feeding-stimulated pancreatic polypeptide (PP) test before and after surgery. A symptom survey was also administered. Twenty patients completed preoperative testing; their mean age was 57 years, and postoperative testing results were available for 16 of them. Of the 20, 14 (70%) had an appropriate increase in PP level with sham-meal preoperatively. All 4 patients with an abnormal preoperative test remained abnormal, and 5 of 12 (42%) with a normal preoperative test had an abnormal postoperative result; thus 9 of 16 (56%) had an abnormal postoperative PP test. In 15 patients, assessments of bowel function were obtained before and after surgery. Six of 15 (40%) patients developed new or worse symptoms (diarrhea in 4, flatus in 2). The symptoms did not correlate with PP results. This suggests that some patients referred for antireflux surgery have evidence of abnormal vagus function that persists after surgery. Many patients (42%) with normal testing before surgery develop an abnormal test after surgery. There was no correlation between PP tests and the development or worsening of bowel symptoms.