Views: 15 Author: Site Editor Publish Time: 2019-05-12 Origin: Site
Pancreatic diseases keep rising with high morbidity in recent years. At the same time, endoscopic operations are replacing open surgeries to some extent in treating pancreatic diseases.
As early as 1983, stent implantation was successfully adopted clinically to expand stricture of pancreatic duct caused by chronic pancreatitis. During the development of endoscopic medical technology and with practical technique accumulation, endoscopic treatment for pancreatic diseases has been paid with great attention owing to advantages of minimal trauma, safety and effectiveness.
MRI, CT, ultrasonography and endoscopic ultrasonography-fine needle aspiration (EUS-FNA) are the common methods to diagnose pancreatic diseases.
In the treatment of pancreatic disease, mostly we need devices as below: fiber duodenal scope, ERCP radiography catheter, sphincterotome, guide wire, pancreatic dilation balloon and pancreatic bougie dilator, Soehandra rotating dilator, plastic pancreatic stent with pusher.
We all know that biliary stents are recommended to treat malignant stenosis, and for benign stricture, it is lacking in clinical evidence due to complicated disease incentives; while stents play important roles in treating both benign and malignant pancreatic diseases.
We have some researches to enlighten you in product choosing:
．What kind of diseases do we apply stent implantation in clinical practice?
Malignant pancreatic cancer: pancreatic cancer, especially pancreatic head cancer shall lead to biliary obstruction and jaundice. The occurrence rate is as high as 80%~ 90%. Plastic stent and metal stent are commonly used.
2. Acute biliary pancreatitis: it accounts for 15%~50% in acute pancreatitis, with 20%~ 35% mortality rate. Generally speaking, ENBD drainage and EST are carried out for clinical treatments.
3. Chronic pancreatitis: in developed countries, chronic pancreatitis is mainly caused by alcoholic pancreatitis; and in most developing countries, it is also related with biliary diseases. The treatment principles are aimed to alleviate pains, to prevent its re-occurrence and to improve the external secretion of pancreas. Endoscopic treatments have the advantages of repeated operation with low complications and morbidity rate and without negative effects on the secretion function of pancreas. Endoscopic treatments do not affect open surgery if necessary afterwards.
According to clinical experience, both EPS and pancreatic dilation should be used to achieve best
operation effect. Stent implantation is proved to be effective. Single plastic stent, multi plastic stents and
retrievable metal stent are commonly used. In China, we use single plastic stent for 70% cases.
According to the researches, it is recommended with treatment sequence “7-8.5-10F”, starting from 7F stent and stent should be changed every three months.
4. Stent implantation for pancreatic schism has good short term effect. Long term implantation shall change the morphologic structure of pancreas, which may lead to fibration, inflammation or atrophy. Normally the stent is recommended to be taken out less than two months.
5. Pancreatic fistula with stent treatment has many successful reports in China. Changhai Hospital in China cured many cases of fistula after cyst surgery. Generally speaking, ERCP and stent implantation at early stage could help the fistula close up. The fistula connected with main pancreatic duct is the indication in this regard.
．Tips for stent implantation
Pancreatic stent has similar implantation method as biliary stent. EPS（Endoscopic pancreatic sphincterotomy）is performed at the first step, if necessary, EPS together with EST. Observe under endoscope to get the guide wire through the stricture. For high degree stricture, pre-dilation is required before stent implantation.
The elements related with stent choices include stricture degree and eclasis of proximal pancreatic duct. If the eclasis of proximal pancreatic duct is obvious, choose stent of diameter 8.5 Fr or 10Fr. Otherwise choose stent of diameter 5Fr or 7 Fr. The diameter of stent should not be larger than the inner diameter of pancreatic duct after dilation. The distal end of stent is normally 1cm longer than the stricture. The proximal end of stent could not protrude too much out of the papilla, on the purpose of avoiding the injury to the duodenal wall.
．Complications and handling suggestions
The short-term complications include acute pancreatitis, bleeding, perforation, cholangitis, cholecystitis and other complications in vascular and respiration systems. The long-term complications mainly occur on patients with long-term stent implantation for drainage, such as blockage, stent migration, and pancreatic duct injury. Most patients could be treated via endoscopes or conservative medical treatment; few are required with open surgeries.
Occurrence rate 5%~20%, the main reason is due to the adhesive protein. According to ample clinical data, for stent with diameter 5FR, 6FR, 7 FR, 50% would be blocked in 6 weeks after implantation, 100% would be blocked in 9 weeks; for stent with diameter 10 FR, only 13% would be blocked 8 weeks after the implantation.
The material of plastic stent should take consideration of blockage prevention.
PE material with smooth and delicate surface could have less protein sediment and therefore keep the patency of stent inner cavity.
Presently, we use stent with bi-lateral wings which could have much less migration, the stent is designed to conform to the anastomotic structure of bile duct and with material of good biocompatibility.
When the stent migration happens, varieties of devices could be used.
To take out the stent from pancreatic duct, devices as stone retrieval basket, ligator, and alligator forceps could be used. If stent migrates to the proximal end and its distal part is embedded into the pancreas head, control the stent by alligator forceps or basket and get it out from embedment. If the distal end of stent is embedded on the opening of pancreatic duct, perform EPS and take out the stent. Another useful device is stent retrieval device Soehendra.
Because the stent is blocking the way of branch pancreatic duct, stone shall be formed in the entrance of branch pancreatic duct to main pancreatic duct. Stone may happen as well on the bypass between stent and the duct wall. Stents may get deformed if the stone is too hard. If the stent is blocked and endoscopic retrieval fails, open surgery should be performed.