The Application Of Jejunal Interposition In Pancreaticoduodenectomy

Pancreat codoudenectomy has been widely adopted as a classic operational paradigm to treat malignant tumors at the heads of pancreas, common bile ducts and surrounding areas of ampulla. However, PD that we use today has gone through a long evolution process. Reviewing the history of PD, it is also the history of preventing and treating pancreatic leakage (fistula). The development of PD underwent three stages:early period (1898-1940); the period of accumulation of experience and innovation (1941-1980) and maturation period (1980-).PD has steps into a mature stage with operational procedures fully standardized after the previous periods. However, the rate of pancreatic leakage (fistula) after PD is about 5%～25% which cause death at a very high rate of 20%～50%. Is there any way that could improve digestive reconstruction of PD to reduce the rate of post-PD pancreatic leakage? If we want to reduce pancreatic leakage (fistula), we have to find the reasons first. There are two reasons:firstly, it is the pancreas size, texture, pancreatic duct diameter and pancreatic function, as well as surgical suture techniques and experience, which are the key factors affecting pancreatic leakage on some patients; secondly, before the intestinal tract functions normally, about 1000～2000ml pancreatic liquor produced by pancreas accumulate around the stoma, but the bile salts in intestinal tract can activate pancreatin for powerful digestion, which may irritate the stoma or pancreatic section to bleed, resulting in pancreatic leakage. It is also the basic condition which causes pancreatic leakage, so from this point, we can know that:1. the pressure around anastomotic stoma is too high; 2. that pancreas activated by bile salts provide the basic conditions for post-PD pancreatic leakage. Thus, is there any way that we could design a new form of digestive reconstruction to divert bile and pancreatic liquor, in order that we can reduce the anastomotic pressure and prevent bile salts from activating pancreatic liquor before the intestine fully recovers.At present there are only two hollow organs to drain pancreatic liquor in PD:jejunum and stomach. In the process of pancreas jejunum anastomosis, we use the same part of the jejunum to anastomose in the order of pancreas, gallbladder and stomach, but whatever form you use can't reduce the pressure around the stoma or completely prevent bile from activating pancreas. However, if pancreas and stomach are anastomotic, then big gastral cavity can reduce pressure around the stoma and prevent bile from activating pancreas. But the greatest defect is that it changes the natural order between pancreas and stomach anatomically and physiologically. Besides, pancreas may be damaged by acid gastric juice and then affect digestive function, and acid gastric juice can also cause excessive pancreatic stump necrosis, fibrosis and secondary obstruction on duct; moreover, it may need another operation after PD because of stomach disease, or face the problem of anastomotic pancreas and stomach. The application of jejunal interposition in PD is to use two segments of near-end jejunum with independent mesenteries to anastomose the pancreas and intestine, and bile and intestine respectively. In this way, bile and pancreatic juice can flow into distal intestine tubes through two separate intestine tubes, which can reduce the pressure at the stoma between pancreas and intestine, and bile and intestine, and prevent bile from activating pancreatic liquor, which theoretically changes the basic conditions for pancreatic leakage.Design an animal experiment centering on jejunal interposition. We should choose domestic dogs as subjects, and have a better understanding of their anatomy on digestion tracts. The vascular arches of near-end jejunum mesentery can provide two segments of jejunums with independent mesenteries, which provides a foundation for receiving jejunal interposition.Specific conditions of the experiment:1. General information Carry out PD on twenty dogs with weight of 14-18kg, of which four are male and the other 16 are female, and give all of them gentamicin sulfate 40000 units, two times a day, keep their intestine in bowel preparation for 3 days.2. Method Keep conventional tracheal intubation anesthesia. Carry out the operation PD on these dogs. Improve the form of digestive reconstruction:to adopt jejunal interposition to reconstruct digestive tract. After cutting off their pancreas and duodenums, use two segments of near-jejunum with mesenteries about 15cm and 20cm, anastomose the pancreas and intestine at the length of 15cm. When anastomosing the pancreas and intestine, we didn't put pipe support in pancreatic duct because of dog's thin pancreas, soft texture and small pancreatic duct. We should adopt double-layer interrupted anastomosis between the pancreas and the end of jejunum, and adopt biliary-enteric anastomosis at the length of 20cm jejunums. The diameter of dog's choledochus is 1.0～1.5cm, so we should put a support pipe in the pancreatic duct and fix it firmly during the process of anastomosis, and suture near-end jejunum, puncture jejunal wall, then put a choledochus pipe support in jejunum and make a purse to embed and fix the bile duct. Adopt gastrointestinal sided anastomosis respectively when remote-end of jejunal interposition is about 10cm and 15cm far away from gastrointestine. Then put an intra-abdominal drainage tube in pancreatic intestine or around the biliary-enteric stoma. Finally, observe the pancreatic leakage after operation.3. The result Operation time is 6 hours in average, and there is no obstacle in blood transportation, but one case of bile leakage, one case of colon necrosis and one case of operative death.Through the use of jejunal interposition in digestive reconstruction of PD on 20 dogs, we can see that:firstly, jejunal interposition is reliable and practical on domestic dogs, because mesentery vascular arches of people and dogs are the same, we can get a conclusion that jejunal interposition is also feasible for people; secondly, the reconstructed alimentary tracts are more in conformity with original physiological structures of the body,which means pancreatic liquor and bile flows into alimentary tract separately; thirdly, the state of jejunal interposition of reducing pancreatic leakage can't be counted in statistics because of little sample and experimental conditions etc. So we can't get such a conclusion that jejunal interposition can reduce pancreatic leakage. Innovative points1. The viewpoint of double pouch jejunum interposition(DPJI) is put forward for the first time in PD;2. Digestive reconstruction is more in conformity with physiology in PD.Possible problems:1. The application of DPJI in PD must increase the number of stomas, stoma leakages, narrow stoma and obstacles of it.2. It increases the difficulty and time of the operation.The study on PD is a difficult and long-time task, which will need lots of medical workers'joint efforts. So I hope we can work together in the future work, in order that we can make PD operations better match physiological structures to minimize the occurrence of postoperative complications, and guarantee all patients high-quality life.