Secondly infection was a severe late complication and common cause of death after necrotizing pancreatitis. In this study, 48(90.1%) patients were confirmed with infection by positive culture from pancreatic necrosis, which was higher than previous studies[3, 5]. This might be resulted from the high rate of tertiary referral (81.1%,43/53) and most of the patients had been diagnosed with infection in previous hospitals. Timing of definitive surgery was an important factor affecting the outcome of IPN patients. Lessons from open necrosectomy demonstrated early operation was associated with extremely high complication rate and mortality[13, 14]. Therefore, delayed surgery was recommended by current guidelines[15, 16]. In our clinical practices, we tried our best to postpone the operation to 4 weeks after the onset of the disease. However, we believed percutaneous drainage should be performed immediately once infection was considered.
Splanchnic(SVT) or portosplenomesenteric (PSVT) venous thrombosis was not rare complication after acute pancreatitis with the incidence of 16.6–25.5%, which might result in sinistral portal hypertension[17, 18]. Previous studies have clearly demonstrated the risk factors, including red blood cell specific volume(HCT), D-dimer, serum amylase, APACHE-II score, and Ranson sore, for SVT or PSVT[19, 20]. About one fourth of the patients developed variable symptomatic manifestations including gastrointestinal bleeding, persistent ascites, oral intake intolerance and even hepatic infarction[21, 22]. In addition to SVT or PSVT, other venous thromboembolism(VTE) in necrotizing pancreatitis, including extremity deep venous thrombosis and pulmonary embolism was also common with the incidence of 16% and 6%,respectively. Previous study showed male gender, history of previous deep venous thrombosis, infected necrosis, development of organ failure, and development of respiratory failure were identified as risk factors for VTE. Recent systemic review demonstrated that about 46.5% patients received anticoagulation therapy, However, rates of recanalization of veins in the treated and non-treated groups were comparable. In our center, anticoagulation therapy was routinely used since we believed it was important to prevent deep venous thrombosis and fatal pulmonary embolism. We did not find the increased rate of bleeding complications.
Surgical or endoscopic mini-invasive debridement has been widely performed in treatment of IPN with promising results, which was recommended by many guidelines. Patients with necrosis confined to lesser sac were special since different approaches, including laparoscopic transgastric, trans-lesser sac, endoscopic transluminal and trans-retroperitoneal approach can be used. In our center, endoscopic transluminal surgery was not routinely performed. The reasons were as follows. First, endoscopic drainage and debridement were still technique demanding. Only one gastroenterologist in our hospital can performed this procedure expertly. It might be not available for IPN patients when necessary. On the other hand, percutaneous drainage and laparoscopic surgery was in the hands of the surgeons and can be performed at any time. Second, endoscopic therapy was much more expensive than surgical therapy in China. Many patients cannot afford the cost of endoscopic treatment, especially when multiple procedures were needed. Third, the most important reason for these patients, was the concerns about the bleeding complications especially in patients with sinistral portal hypertension. In this study, the overall hemorrhage rate was 9.4%, and none of the patients developed intraoperative bleeding from gastric varices in LTGN group, which means LTGN was safe in treatment of WON with sinistral portal hypertension. Postoperative hemorrhage was potential lethal complication after debridement surgery. Three cases (5.7%) died of severe hemorrhage from splenic artery. For the early postoperative bleeding, immediately surgery or arteriography should be performed to identify the criminal vessels. Previous studies confirmed that the common bleeding site after IPN included branches of splenic artery, superior mesenteric artery, left gastric artery, gastroduodenal artery and left colonic artery. Bleeding from the branches of the splenic and left gastric arteries can be embolized safely without serious consequences. In our center, there were cases of colonic leakage after left colonic artery embolization and duodenal fistula after gastroduodenal artery embolization. In case of emergency massive hemorrhage, all drainage tubes should be removed at the bedside, and packing hemostasis performed immediately, then transferred the patient to the intervention center or operating room.
Pancreatic fistula was common in LATLSN group with incidence of 37.5%, which was significantly higher than LTGN group. In studies comparing surgical with endoscopic approach, the rate of pancreatic fistula in surgical group was similar with our report[5, 6]. Pancreatic fistula will prolong the duration of intubation and hospital stay. Additional endoscopic or surgical therapy might be required in some patients. In our center, patients with pancreatic fistula were routinely given somatostatin. And 10 out of 12 cases in this study recovered in 12 weeks without any additional intervention. The other 2 cases received endoscopic stents treatment and were recurred in 4 weeks. In LTGN group, 76.2% of the patients were covered after single operation, only 2(9.5%) and 3(14.3%) patients needed additional percutaneous drainage and endoscopic surgery, respectively, which was comparable with the results of endoscopic treatment.
Incisional hernia was a common long-term complication after LATLSN surgery with the incidence of 12.5%. However, LTGN could avoid this complication completely. Furthermore, LTGN did not increase the rate of WON recurrence and other long-term complications, including new-onset diabetes and pancreatic exocrine insufficiency. Therefore, LTGN combined the advantages of less complications in endoscopic surgery and high efficiency in surgical approach[9, 25]. Even in WON patients with sinistral portal hypertension, LTGN did not increas the risk of hemorrhage.