Endoscopic papillotomy and papilloplasty: Effects on sphincter of Oddi functionality and outcomes

This Editorial refers to the article by X. Yan et al., p 962-969 of this issue. In the late 1960s, it was possible to evaluate the biliary tract via percutaneous transhepatic cholangiography, but there was no way to contrast the pancreatic duct. Since there was no computed tomography or magnetic resonance imaging at that time, physicians had no means to morphologically assess the pancreas, and the only way to diagnose pancreatic cancer was via autopsy. In Japan, a type of endoscope called a “fiber duodenoscope” was developed for direct pancreatography. The first successful pancreatography was performed in 1969 and the following technique was reported in 1970: Retrograde Pancreatography and Cholangiography by Fiber Duodenoscope.1 This article was the first to describe the term “retrograde”, and the term is also included in the current “endoscopic retrograde cholangiopancreatography (ERCP)”, and the pancreatic angiography that appeared in the article was of great historical importance. In the early 1970s, common bile duct (CBD) stones were treated by surgical papillotomy and surgical papilloplasty. Kawai et al. developed a device called sphincterotome, which combined electrocoagulation and incisional techniques for endoscopic stone removal using a fiber duodenoscope; it was used for the first-ever successful endoscopic stone removal.2 The procedure was later renamed endoscopic “sphincterotomy” (EST) in reference to the sphincterotome, and current use of the procedure is widespread globally. The procedure made endoscopic papillotomy possible but could accommodate papilloplasty. In 1983, endoscopic papillary balloon dilation (EPBD), a technique to dilate the papilla orifice without making an incision, was reported and was expected to preserve the function of the sphincter of Oddi.3 However, the bile duct diameter limit for the performance of the technique did not allow the treatment of large stones. In 2003, endoscopic papillary large balloon dilation (EPLBD) was reported, but EPLBD did not guarantee preservation of the function of the sphincter of Oddi.4 It has been well known that the sphincter of Oddi prevents duodenal content reflux into the bile duct. Therefore, loss of the function of the sphincter of Oddi by endoscopic papillary procedures was thought to lead to duodenobiliary reflux. Many studies have been performed to reveal how endoscopic papillotomy affects the function of the sphincter of Oddi.5-8 According to a study in which 419 patients who underwent EST (the period ranged from 1 month to 20 years; average 122 months) were followed-up, cholangitis and liver abscess occurred in 31% and 11% of patients, respectively. Of patients with residual intrahepatic stones, recurrent stones occurred in 12.3% of cases.7 Interestingly, all recurrent stones were reported as bilirubin stones, irrespective of the type of stone observed at sphincterotomy. This discrepancy indicated that dysfunction of the sphincter of Oddi was a risk factor for stone formation due to bile reflux. According to a follow-up study of more than 1,000 patients who underwent biliary-enteric surgical drainage (transduodenal sphincteroplasty, choledochoduodenostomy, and hepaticojejunostomy), the incidence of biliary tract cancer was 5.8%, 7.6%, and 1.9% in patients who underwent transduodenal sphincteroplasty, choledochoduodenostomy, and hepaticojejunostomy, respectively.8 Since the carcinogenic rates of transduodenal sphincteroplasty and choledochoduodenostomy, where duodenobiliary reflux occurred, were significantly higher than those of hepaticojejunostomy, which did not result in duodenobiliary reflux, it was concluded that duodenobiliary reflux increases the risk of carcinogenesis. On the other hand, a population-based study found that although patients who underwent EST had a higher risk of acute pancreatitis and cholangitis in the long term compared with those not treated with EST, no increased risk of malignancy in the pancreaticobiliary tract was observed.6 In a study that compared outcomes of EPBD and EST, it was shown that late complication rates and stone recurrence rates were significantly lower after EPBD than after EST (5.3% vs. 17.3%, P = 0.009; 4.4% vs. 12.7%, P = 0.048, respectively). A comparison of EPBD and EPLBD using propensity score matching revealed that EPLBD without EST removed large CBD stones more efficiently but was associated with worse long-term outcomes than EPBD.5 As these findings indicated, endoscopic papillotomy has been developed from EST to EPBD and EPLBD, and most CBD stones including large stones could be treated endoscopically, although endoscopic papilloplasty is still remains undeveloped. As a different approach, the needle-knife fistulotomy (NKF) is a non-papillary approach to the biliary tract and useful in cases of difficult biliary cannulation. With NKF papillary function is maintained and the risk of postoperative pancreatitis, a fatal complication of ERCP is eliminated. The efficacy of NKF for treating CBD stones has been examined relative to conventional methods.10 In addition, the usefulness of the infundibulotomy, similar concept as fistulotomy, for treating CBD stones has also been reported. However, these techniques are not yet mature and need to be further developed to be widespread. In this issue, Yan et al. reported the feasibility and efficacy of an endoscopic papilloplasty procedure called “endoclip papilloplasty” in restoring the function of the sphincter of Oddi in patients with choledocholithiasis with large (≥10 mm) CBD stones.9 Endoclip papilloplasty is a novel and unique endoscopic papilloplasty. In this study, large CBD stones were treated using not EPLBD but only EST. After performing EST and treating stones, a 7.5 Fr × 26 cm biliary plastic stent was placed. The stent was long and made of a plastic nasobiliary drainage tube (Boston Scientific Corporation, Marlborough, MA, USA). After a long PS placement, an EST incision was closed in a zipper fashion from its proximal to distal end using a rotatable clipping device (Micro-tech, Co., Nanjing, China). Among the 30 patients enrolled in this study, 14 underwent sphincter of Oddi manometry (SOM) using triple-lumen aspirating and perfusion manometry (Medical Measurement Systems, Enschede, Netherlands) before EST, immediately after EST, and 3 weeks after endoclip papilloplasty. As a result, after EST, manometric data were reduced from that determined before EST, but no significant difference was observed between the manometric data before and after the endoclip. The authors concluded that endoclip papilloplasty is useful for repairing the sphincter of Oddi. As described above, endoscopic papilloplasty has not been developed to date; therefore, this report is of great interest. The authors' eagerness to repair the function of the sphincter of Oddi should be respected. However, there are concerns related to the use of this novel technique. The first is whether closing the incision really facilitates repair of the function of the sphincter of Oddi. When necessary, the sphincter of Oddi must not only contract but also release. If the PS is removed and scarring occurs, the degree of obstruction may be so great that it prevents bile flow. Furthermore, the disappearance of the sphincter of Oddi results in not only increased duodenobiliary reflux, but also increased bile juice outflow. It has been possible that the continuous flushing of bile juice maintains normal biliary tract conditions. As the authors maintained, endoclip papilloplasty certainly restores manometric data that were once degraded by EST to values consistent with those determined before EST, but whether manometric data restoration is synonymous with restoration of the function of the sphincter of Oddi is debatable. Additionally, it is possible that a situation where the clip remains without falling off occurs. Whether the function of the sphincter of Oddi is maintained or is lost, duodenobiliary reflux will exist, and risk of stone relapse is present. If the clip remains, there is increased risk that endoscopic stone treatment will not be possible. Finally, in cases where the lateral oral protrusion is not long, endoscopic papilloplasty will be difficult. However, despite these concerns, the authors described a previously unreported endoscopic papilloplasty procedure, and the work should be greatly appreciated for its novelty and for their efforts regarding the preservation of papillary function. In the future, long-term observational studies to investigate the technique are needed. Further, the novel concept of endoscopic papilloplasty using methods, other than clipping, is also expected. In this editorial, we present about the theme of “history of endoscopic papillary procedures”, “effect of endoscopic papillary procedures on function of the sphincter of Oddi” and “endoscopic papilloplasty”. As can be understood from these histories and efforts, the passion of endoscopists to contribute to the patients by performing endoscopic stone treatment has continued and developed over the past 50 years. The endoclip papilloplasty reported in this paper is very simple and is a procedure that anyone can perform at a look. However, it is important to realize that this technique was also created based on the development of devices. With conventional clips, it was difficult to perform several clippings in a zipper fashion using the ERCP scope. This technique has become possible because of the development of the clip. In the future, a stone treatment protocol that considers concepts discussed here could become a gold standard, and future device development that we have yet to meet is expected. Authors declare no conflicts of interest for this article. There was no funding support for this paper.