Endoscopic therapy of recurrent acute pancreatitis
ABSTRACTEndoscopic therapy has emerged as an alternative to surgery for the subset of patients with acute recurrent pancreatitis whose disease is due to gallstones or other mechanical processes that obstruct the outflow of the pancreas. In this article, the authors review the specific situations in which endoscopic therapy might be useful in patients with acute recurrent pancreatitis.
KEY POINTS
- Recurrent attacks of acute pancreatitis can be prevented only by determining and treating the underlying cause.
- Endoscopic procedures can cause anxiety and carry a risk of bleeding, perforation, and pancreatitis. The risks, benefits, and other treatment options should be discussed with the patient.
- Endoscopic therapy is now the preferred treatment of sphincter of Oddi dysfunction at centers that have experience with this technique.
- In patients with pancreas divisum and recurrent acute pancreatitis, surgical and endoscopic minor sphincterotomy are equally effective.
PANCREAS DIVISUM
Pancreas divisum is the most common congenital anomaly of the pancreatic duct. Autopsy studies show it occurs in 5% to 10% of the population.51–53
At approximately the 5th week of gestation, there are two pancreatic buds: a ventral and a dorsal bud. The ventral bud eventually gives rise to part of the pancreatic head and uncinate process of the pancreas in the adult. The dorsal bud eventually gives rise to the rest of the pancreatic head, the pancreatic body, and the pancreatic tail. At 6 to 7 weeks of gestation, the ventral bud rotates clockwise and lies posterior to the dorsal bud. At this stage, both the dorsal and ventral pancreata have their own ducts, which do not communicate with each other. Normally, the ventral and dorsal pancreas and their ducts fuse together at 8 weeks of gestation; in people with pancreas divisum, this ductal fusion does not occur.51
The pancreas secretes 1.5 L of fluid per day. Normally, 90% to 95% of this volume drains through the major papilla. In people with pancreas divisum, 90% to 95% of the fluid drains through the minor papilla.
People with pancreas divisum are a heterogeneous group. Most have no symptoms, and their ductal anatomy is diagnosed only incidentally. However, a subgroup is prone to develop acute pancreatitis. The cause is thought to be the small diameter of the minor papilla, which poses a relative obstruction to the flow of pancreatic juice.54 Direct support for this theory comes from a study in which investigators measured pancreatic ductal pressures in eight people with normal anatomy and six people with pancreas divisum. The pressure in the main pancreatic duct in those with pancreas divisum was significantly higher than in those with normal anatomy.55 Additional evidence in favor of this theory is the effectiveness of treatment, which involves widening the minor papillary opening (minor papillary sphincterotomy).
Diagnosis of pancreas divisum
The diagnosis of pancreas divisum is based on imaging studies, and ERCP remains the gold standard for patients with equivocal results on noninvasive imaging. However, MRCP, especially secretin-enhanced MRCP, is as accurate as ERCP. In most cases, MRCP has replaced ERCP for the diagnosis of this condition, although a recent study suggests that MRCP is inferior to ERCP in the diagnosis of pancreas divisum.56 We recommend secretin-enhanced MRCP for this purpose.
Computed tomography and endoscopic ultrasonography can also diagnose pancreas divisum, but their diagnostic accuracy is lower than that of ERCP and MRCP.
Minor papillary sphincterotomy
Treating recurrent pancreatitis due to pancreas divisum involves relieving the relative obstruction of the minor papilla by minor papillary sphincterotomy. This can be done surgically or endoscopically (Figure 1).
Surgery. No randomized, controlled study has yet assessed the efficacy of surgical sphincteroplasty for recurrent pancreatitis in patients with pancreas divisum. However, retrospective studies and one prospective study have been published.57,58
In the retrospective study with the largest number of patients, Warshaw et al57 reported their experience in 49 patients who had recurrent pancreatitis due to pancreas divisum. After surgical sphincteroplasty, the patients were followed for a mean of 53 months; 40 (82%) of the 49 patients had no further episodes of acute pancreatitis during this time.
Bradley and Stephan58 studied 37 patients with pancreas divisum and recurrent pancreatitis.58 After surgical sphincteroplasty, the patients were followed for a mean of 60 months; 31 of the 37 patients had no further attacks, a success rate of 84%.
Endoscopic therapy. As with surgical therapy trials, most trials of endoscopic therapy of recurrent pancreatitis in patients with pancreas divisum are small case series. In a retrospective study with one of the largest number of patients, Heyries et al59 reported their experience with 24 patients with pancreas divisum and recurrent pancreatitis. After undergoing endoscopic minor papillary sphincterotomy, all patients were followed for a mean of 39 months, during which 22 (92%) did not have further episodes of acute pancreatitis.
In the only randomized controlled trial available, 19 patients with recurrent pancreatitis and pancreas divisum underwent either no treatment or endoscopic minor papillary sphincterotomy.60 In the treatment group, 9 of 10 patients had no further episodes of acute pancreatitis during the 3 years of follow-up, while 6 of 9 patients who were randomized to no treatment had at least one episode.60
Although surgical and endoscopic minor papillary sphincterotomy are equally effective, endoscopic therapy is preferred since it is less invasive, is associated with less morbidity, and costs less. It is also more convenient for patients, since it is an outpatient procedure. Surgical treatment is usually reserved for those in whom endoscopic treatment has failed or is not technically possible.
