Kenneth R. DeVault, Grettel K. Wentling, Sami R. Achem, Ronald A. Hinder, Mayo Clinic College of Medicine, Jacksonville, FL

Introduction: Bloating and diarrhea, when occurring after antireflux surgery, are often blamed on an inadvertent vagotomy, yet there are few data concerning the true incidence of vagal injury in this surgery. We sought to evaluate vagal nerve integrity before and after antireflux surgery. Method: Patients referred for antireflux surgery were recruited to the study. Patients with disorders associated with vagal dysfunction (diabetes, renal dysfunction, etc) or who took medications with anticholinergic effects were excluded. Each subject underwent a sham-feeding stimulated pancreatic polypeptide (PP) test before and, in the majority of the patients, after antireflux surgery. The PP test consists of two baseline samples obtained prior to the standardized sham meal and follow up samples at 5, 10 , 15, 20, 25 and 30 minutes post sham feeding. Control data from our institution indicate that the PP level will increase by at least 25 pg/ml in over 70% of normals after sham feeding. Results: 20 patients completed preoperative testing with a age of 57 years (range 36-80). 14/20 (70%) of these patients with severe reflux had an appropriate increase in PP level with sham meal in the preoperative period. Follow up testing was available in 16/20 patients performed a mean of 45 days (range 6-134) after the surgery (12 normal and 4 abnormal preop). 5/12 (42%) who had a normal preoperative test had an abnormal postoperative result. All four of the patients with an abnormal preoperative test remained abnormal. Thus, in the 16 patients studied after surgery 9/16 (56%) had an abnormal PP test. The increase in PP was also less after surgery (64 preop vs 41 postop, p=0.03). In 15 patients, detailed symptom assessments of their bowel function were obtained before and after their surgery. 6/15 (40%) patients developed new or worse bowel symptoms after surgery (diarrhea=4, flatus=2). Importantly, there was no correlation with the results of PP testing and the development of post-operative symptoms. Conclusions: These results suggest that a subset of patients referred for reflux surgery will have abnormal vagal function as assessed by PP testing that persists after surgery. More importantly, 42% of patients with a normal test prior to surgery will develop an abnormal test after surgery. On the other hand, in this small study, there did not appear to be a correlation between these results and the development or worsening of bowel symptoms.