The pancreas has an important place in nutrition and metabolism with its anatomical-physiological features, exocrine and endolrin secretions. Its anatomical location, vascular structure and ductal structure, which has an active role in exocrine secretion, increase its importance. While pancreatitis, tumors and complications of pancreatitis are the most common pathologies, fistulas developing both traumatic and after surgery maintain their importance as an important problem of surgery.
As a matter of fact, 15-25% fistula-leakage rates after pancreatico duodenectomies performed for various reasons reveal the importance of the issue. carries out.
SURGICAL ANATOMY
Porta hepatis, extrahepatic bile ducts and pancreatic anatomy are one of the regions in the human body where anomalies are very common. This is why it has been the center of attention throughout the history of medicine. Current medical research on the biliary tract has started from the 17th century.
Enlargement (ampulla) in the distal common bile duct was first reported in 1685 by Govert Bidloo (1649-1713) and Francis Glisson (1597-1677), although the intramural part of the common bile duct was surrounded by annular fibers that prevent reflux; In the literature, they have been called by the names of Abraham Vater (1684-1751) and Ruggero Oddi (1864-1913).
In Edward Allen Boyden’s (1886-1976) studies on the sphincter and published in 1957, it was described by Oddi that the distal choledochopancreatic sphincter consists of three parts, the part located in the papilla Wateri; it has been revealed that the other two parts are located on the choledochal and Wirsung sides of the choledochopancreatic junction.
The major one of the pancreatic ducts is named after Wirsung, while the minor one is called the Santorini duct. The ducts increase in width as they go from the tail to the head of the pancreas; Wirsung diameter, 0.9-2.4 mm in the tail, 3 mm in the body and 3.1-4.8 in the head of the pancreas
reaches mm. Wirsung and Santorini ducts converge in 60% of cases and open into the duodenum. In 30% of cases, the Santorini canal ends blindly without opening into the duodenum, even though both canals merge. In the remaining 10% of cases, any combination is found in which the Santorini canal is dominant. However, these malformations do not have much surgical significance.
On the other hand, Papilla Vateri is a slight protrusion in the duodenal mucosa. It is on the posteromedial surface of the middle of the second part of the duodenum. The distance of the papilla from the pylorus varies between 7-10 cm. Rarely, the papilla may be located in the third part of the duodenum. Here, the common (70%) or separate (30%) orifices of the common bile duct and Wirsung canal are found.
There are sphincters at 2 points in the biliopancreatic tree. The first of these is the sphincter in the neck and duct of the gallbladder. Heister valves (or spiral valves) formed by the mucosal pleating in the neck of the gallbladder and sphincter sac formed by thickened circular muscle fibers in the ductus cysticus provide control of the functions of the sac. This sphincter normally allows bile from the liver to pass into the sac, while preventing it from emptying. After food intake, with the effect of gastrointestinal hormones, especially cholecystokinin, it causes an increase in peritaltism while the circular muscle fibers relax. As a result, the sac empties. The second sphincter, the sphincter of Oddi, located at the end of the collegium, is normally closed, while it relaxes with food intake and the bile accumulated in the bilio-pancreatic tree allows the pancreatic fluid to flow into the duodenum.
ETHIOPATHOGENESIS
The most common cause of pancreatic fistulas is pancreatectomy. Less frequently, it may occur after trauma, drainage of pancreatic pseudocysts, or local excisions of pancreatic tumors and/or biopsies. It also occurs much less frequently after surgical interventions on neighboring organs or as a result of perforation of pancreatic tumors.
Despite the developing surgical technique and the opportunities provided by the medical industry, the rate of fistula development after pancreatectomy has not changed. This rate still varies between 15-25% in different series. Leakage from anastomoses performed in surgical interventions (head or subtotal excision of the pancreas) in which the Boyden sphincter is removed is a common complication; It is a complication that occurs as a result of inadequate surgical technique. In such cases, if there is no stenosis in the ductal anastomosis, the negative pressure created by intestinal peristalsis will be a factor in the closure of the fistula. In distal pancreatectomies, failure to close the pancreatic duct stumps may result in persistent and high-output pancreatic fistulas.
Anatomical location is the most important feature in the formation of post-traumatic pancreatic fistulas. The pancreas, which is perpendicular to the lumbar vertebra axis and just in front of it, is extra-peritoneal. The peritoneum covers only the anterior surface, while the posterior surface is without peritoneum. Moreover, the immediately starting regions of the neck and body part correspond to the trage of the vertebral column.
With the blast effect of blunt abdominal traumas, the pancreas is under pressure from both directions on the vertebral column, resulting in crushing injuries. When parenchymal damage occurs as a result of these injuries, varying degrees of pancreatitis; In case of canal injury, it may first cause complications such as collection, hemorrhage, pseudocyst, infection and then fistulas.
CLINICAL FINDINGS AND DIAGNOSIS
Pancreatic fistulas are characterized by clear-colorless fluid coming from the wound or drain after previous surgery. Fistula flow may be at different levels. This amount can vary from 10-15 ml to over 1000 ml. The flow rate increases 1-2 days after the flow starts. In the following days, it gradually decreases. A high level of amylase in the fluid coming from the fistula (may vary from 3 times the upper limit to 10,000-50,000 Somogy units) makes the diagnosis of pancreatic fistula.
5.9 Because the level of amylase in pancreatic fluid is 50,000 Somogy units. The high amylase content of the fistula is an indication that the pancreatic fluid has escaped.
ERCP, on the other hand, is useful in treatment as well as definitive diagnosis-localization opportunities.
Pancreatic fistulas have four major complications.
1. Fluid-electrolyte loss,
2. Infection,
3. Bleeding,
4. Opening to neighboring organs (fistulization).
In high-output fistulas (>1000 m/day), dehydration, hyponatremia, hypokalemia, hypochloremia, and bicarbonate deficiency may develop due to fluid and electrolytes lost from the fistula and restriction of food intake. If left untreated, metabolic acid can occur. Microorganisms coming from both the hematogenous route and the fistula cause infection. The resulting infection
ions accelerate the necrosis by increasing the malnutrition in the tissues.
Elastase, phospholipase A, trypsin, and chemotrypsin, which are inactive in the pancreatic fluid, become active when they encounter bile acids, and erosion may occur in the pancreatic tissue and vascular structures. This can lead to serious damage to the vessels and fatal bleeding.
