**8. Disconnected pancreatic duct syndrome**

While parenchymal destruction in pancreatic necrosis confers significant morbidity and mortality, the seriousness of this condition can be further compounded by concurrent disruption of the pancreatic duct. Disconnected pancreatic duct syndrome (DPDS) occurs when the remnant of pancreas distal to the necrosis, and duct disruption, remains viable and continues to release digestive enzymes into the retroperitoneum. DPDS most commonly occurs in the setting of severe acute pancreatitis, and can be found in up to 46% of patients with pancreatic necrosis [50]. DPDS can also occur as the result of trauma and chronic pancreatitis. The clinical presentation of DPDS is heterogenous. Some patients are asymptomatic and the injury is incidentally diagnosed on radiology. While others may have early satiety due to the size of the resulting fluid collection or symptomatic ascites [51, 52].

DPDS is an often overlooked complication due to the low accuracy of imaging in differentiating between full-thickness pancreatic necrosis, affecting the pancreatic duct, and partial thickness or peripancreatic necrosis. Often multiple imaging modalities are required for accurate diagnosis, which in turn leads to delays in diagnosis, increased morbidity, and increased costs [53–55]. Diagnostic criteria for DPDS include: necrosis of ≥2 cm of pancreatic parenchyma, viable pancreatic tissue distal to the area of necrosis, and extravasation of contrast when injected into the main pancreatic duct during ERCP [56].

Once DPDS is diagnosed, choice of intervention is dependent on the patient's clinical condition and the phase of disease. As in pancreatic necrosis without DPDS, intervention during the acute phase, when inflammation is high, is not only challenging, but also hazardous. Although the historical standard of care for these patients was surgery, if a patient deteriorates during the acute phase, initial therapy should be percutaneous or endoscopic. Percutaneous drainage, although useful as a temporizing measure, especially in unstable patients, is unlikely to succeed as monotherapy [57, 58]. Although success rates are dependent on the extent of necrosis, transpapillary and transmural endoscopic interventions have better shortterm outcomes, with up to an 87% success rate of fistula resolution [50, 59, 60]. However, in order for endoscopic treatment to be successful, multiple interventions are often required, including hybrid approaches with percutaneous drains. Further, long-term data regarding patency and migration of indwelling stents is not available [60, 61]. Thus, percutaneous and endoscopic treatments remain temporizing measures, rather than definitive treatment, for DPDS, except for in patients who are poor surgical candidates [62].

Once a patient reaches the late stage of disease, or if a patient deteriorates despite optimal percutaneous and endoscopic intervention during the acute phase, surgery becomes the primary treatment for DPDS. Because of the technical difficulty of operating in the retroperitoneum after tissue planes have been obscured by inflammation, and because of the frequency of splenic vein thrombosis, and resulting sinistral portal hypertension, this operation is usually performed with a midline laparotomy and not laparoscopically [63].

Surgery for DPDS consists of resection of the distal, disconnected pancreas, and creation of internal drainage tracts. These techniques may be used independently or in combination. When the entirety of the disconnected pancreas is resected, splenectomy is also performed in almost all cases. However, when a pancreatojejunostomy, pancreaticogastrostomy, or fistuloenterostomy is made with the viable distal pancreas, the spleen may be preserved, in addition to preserving the pancreatic remnant. In this way, internal drainage not only provide a conduit for pancreatic secretions, but also decreases the risk of exocrine pancreatic insufficiency and

diabetes. Importantly, patients who undergo internal drainage, compared to other surgical modalities, also have lower incidence of organ failure, development of pancreatic fistula, and need for long-term percutaneous drainage [50, 64].
