Surgery for Pancreatic Divisum
Embyology of the Pancreas
In order to understand the entity of pancreatic divisum, it is important to understand how the pancreas develops in the uterus. The pancreas is formed in the uterus from the fusion of two separate pancreatic ducts to form the adult pancreas.
The one duct is called the dorsal duct and the other duct system is called the ventral duct. With development of the pancreas in the embryo these two duct systems fuse together to form the normal pancreatic duct that is found in the adult. The dorsal duct drains the major portion of the pancreas in the embryo, however in the adult pancreas drains only a small portion of the head of the pancreas. The ventral ductal system drains only a small portion of the embryonic pancreas, however, it drains more than 70 percent of the adult pancreas.
Because the dorsal duct drains the majority of the pancreas in the embryo it opens into the intestine through the major papilla or the main pancreatic duct opening in the adult that is much wider than the minor papilla or the small duct opening. Since the ventral ductal system drains only small portion of the embryonic pancreas it opens into the minor papilla.
What is Pancreatic Divisum?
In the adult the dorsal duct system becomes connected with the ventral duct system. If the two duct systems fail to fuse in the embryo then the condition is known in the adult as pancreatic divisum. Here the ventral duct that is responsible for draining the major portion of the pancreas in the adult opens through a tiny duct or the minor papilla into the duodenum while the dorsal duct that is responsible for draining only 20% or less of the pancreas opens into the major papilla or the main pancreatic duct opening.
In some patients this give rise to a functional obstruction for drainage of pancreatic juice in the duodenum. It is important to note that pancreatic divisum is a normal finding in many people and can occur up to 2% of the normal population. In the majority of people this condition does not give rise to any problems and they live a normal life. In a minority of people the drainage of the main pancreatic duct through a tiny opening into the duodenum can give rise to obstruction and attacks of recurrent pancreatitis. Some patients develop severe chronic pain with development of chronic pancreatitis.
Medical Treatment of Pancreatic Divisum
The treatment of patients who have pancreatitis or pain from pancreatic is to increase the size of the opening of the minor papilla in to which the main pancreatic duct opens. A gastroenterologist accomplishes this. During the endoscopy, the minor duct is identified cut widely open. The endoscopist often places a pancreatic duct stent across the minor papilla to provide drainage for the pancreatic juice. Some patients require multiple stent placements.
It is important to note that if the patient does not respond or has a limited response to the initial stent placement then there probably is not a significant benefit from repeated stent placements. Furthermore, repeated stent placements may cause further damage in the duct leading to chronic pancreatitis.
Surgical treatment of pancreatic divisum
Surgical sphincterotomy is an alternative to medical sphincterotomy. In this procedure the surgeon identifies the minor duct and cuts it open. The surgeon is often able to create a larger opening for drainage of pancreatic juice. Excellent results are reported with a surgical sphincterotomy and this procedure should be considered in selected patients fail endoscopic medical treatment.