Reply to Dr. Mosca
Authors: R. Enns, J. Baillie
Journal: Endoscopy (2002)

Dear Sir,the comments raised by Professor Mosca are provocative and reflect many of our opinions with regard to ”who should perform ERCP“. With the decreasing number of diagnostic procedures and increasing number of options for biliary tract imaging, it is of critical importance that physicians performing ERCP are not only fully equipped technically, but also possess a full breadth of knowledge regarding the advantages and disadvantages of various alternatives available. As demonstrated by Freeman et al. [1], the number of cases one performs does appear to be reflected in outcomes. Physicians who routinely performed fewer than one sphincterotomy per week had a greater complication rate than those performing more procedures. For these reasons, most large centers have created specialized biliary services in an effort to ensure that a few physicians maintain a high level of skill in this advancing field. Our study [2] was designed to assess risk factors for perforation. In any effort to do this, comparator groups would be required. As described in the methods section, we performed a case-control study in an attempt to identify risk factors for perforations related to ERCP. The baseline group consisted of patients with normal ERCP and the other comparative group comprised patients with pancreatitis. The study group was that group of patients with perforation. The patients were randomly selected. This is the basis for performing a case-control study to assess risk factors related to a certain procedure. Although there were 10 000 ERCPs in the database, most were not normal, and there were only 33 perforations. For the purpose of a case-control study, a comparison group was required. Although there are always limitations whatever group one selects as a comparison, we felt that a group with pancreatitis (i. e., a group, which suffered another complication, selected at random) might give us insights into risk factors. The ideal setting would be that of a controlled trial; however, since perforations are not common, any type of controlled trial would be an enormous undertaking; if not an impossible one. Therefore, we used a case-control study to evaluate this issue as well as possible. Although there were limitations in this approach, we reported on the largest group of perforation patients (even though they were somewhat diverse) that has been evaluated in an in-depth approach, in an attempt to further elucidate the risk factors for their complication. We concentrated only on perforations, unlike other studies, which have often concentrated on pancreatitis or a range of complications occurring during ERCP. We have successfully performed many procedures on Billroth II patients; however, the data with regard to the percentage of patients who suffered perforation or other complications have not been analysed. Logically, as noted by Dr. Mosca, it does appear that altered anatomy (i. e., Billroth II gastrectomy, duodenal stricture) probably slightly increases the risk of perforation. Unfortunately, these are rare conditions and caution is recommended in drawing conclusions from complications occurring in only one or two patients. In our evaluation we did include patients who we classified as having ”guide wire“ perforations. These perforations occurred with varying types of guide wires, during difficult cannulations or manipulation through distal strictures. They were usually diagnosed at ERCP when contrast was noted to extravasate, in patients who had not had a sphincterotomy. We do agree that one of the inferences from the paper (as supported by previous published reports) is that ERCP is safe, in expert hands. We believe that adequately trained endoscopists, who perform ERCP on a regular basis, will have the best therapeutic results with the lowest complication rates.