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Conceptually, drainage of pancreatic pseudocysts can be accomplished surgically, percutaneously, or endoscopically.

Open surgical drainage, traditionally the treatment of choice in surgically fit candidates, entails the creation of a cystgastrostomy, cystduodenostomy, or Roux‐en‐Y cystjejunostomy, depending on the location of the pseudocyst and its anatomical relationship to the stomach and duodenum. The procedure has been increasingly performed laparoscopically in recent years and can also be combined with pancreatic resection to address concurrent pancreatic ductal disease. A randomized controlled trial comparing endoscopic and surgical cystgastrostomy for pancreatic pseudocyst drainage reported equivalent efficacy and recurrence rates, with shorter hospital stay, improved quality of life, and lower cost in the endoscopic drainage group [8].

Percutaneous drainage is performed in centers with appropriate interventional radiology expertise and entails ultrasound‐ or CT‐guided placement of a plastic catheter into the pseudocyst, usually utilizing a retroperitoneal approach. Although less invasive than surgical drainage, reliance on this method may present logistic challenges in patients with pseudocysts located in the vicinity of the pancreatic head and neck for whom a transperitoneal (or even transhepatic) drainage approach may be required. Moreover, the procedure carries the risk of creation of a pancreato‐cutaneous fistula, while local complications such as catheter migration and infection are not uncommon.

Endoscopic transluminal drainage has become the mainstay of management for the overwhelming majority of pancreatic pseudocysts in recent years. Transpapillary drainage is another form of endoscopic therapy that is discussed later in this chapter. Hybrid approaches combining the two endoscopic drainage modalities have also been described.

Transluminal stent‐assisted drainage entails the creation of a fistula between the pseudocyst and the lumen of the stomach and duodenum with or without electrocautery assistance and/or wire‐guided balloon dilation of the fistulous tract, followed by placement of one or more stents across the stoma. In early iterations of the procedure, drainage was accomplished with a duodenoscope or therapeutic gastroscope targeting the bulging portion of the stomach or duodenum for electrocautery‐assisted transluminal fistula creation and stent placement. More recently, EUS‐guided transluminal drainage has become the standard of care for drainage of pancreatic pseudocysts, facilitating drainage of nonbulging pseudocysts through a safe, vessel‐free drainage window. Two randomized controlled trials have reported significantly higher technical success rate for EUS‐guided drainage of pancreatic pseudocysts compared to the conventional “blind” approach [9,10]. Prerequisites for EUS‐guided drainage include apposition of the walls of the pseudocyst and stomach or duodenum with a depth of less than 1 cm from the tip of the echoendoscope, an avascular plane, and a mature pseudocyst wall. Plastic stents have conventionally been used. Two main techniques for creation of a transluminal fistula prior to placing plastic stents have been described, both utilizing continuous EUS guidance. In the first technique, the pseudocyst is first punctured with a 19‐gauge needle. An 0.035 or 0.025 inch (0.889 mm or 0.635 mm) wire is then advanced through the needle and coiled into the pseudocyst, usually under fluoroscopic guidance although the procedure can be performed entirely under EUS control. The tract is then dilated using a balloon dilator up to 10 mm, depending on the thickness of the pseudocyst wall. Dilatation with a graduated (4‐5‐7 Fr) biliary dilator may be required prior to balloon dilatation. The other commonly used approach utilises a 10‐Fr cystotome instead of a 19‐gauge needle. The cystotome device (Cook Medical, Bloomington, IN) comprises a needle knife tip, a distal 5‐Fr inner catheter, and a 10‐Fr outer catheter equipped with a diathermy ring at its distal tip. The pseudocyst is punctured using the needle knife tip and the 5‐Fr inner catheter advanced into the cavity. The 10‐Fr catheter is then advanced over the 5‐Fr inner catheter using the ring diathermy to gain access to the pseudocyst. The inner 5‐Fr catheter is then removed and at this stage two 0.035 inch wires can be introduced, with balloon dilatation performed over one of the wires. Placing two wires facilitates rapid second stent placement (if required) following balloon dilatation as the endoscopic view is often suboptimal due to the rapid egress of fluid following dilatation of the tract. Whichever approach is used, one or more plastic pigtail stents are then placed across the stoma. Whilst many experts favor the placement of two plastic double‐pigtail stents, there is no randomized study showing benefit of multiple stents over one stent. In a retrospective study, there was no treatment benefit of multiple stents over one stent or association with stent size (7 Fr vs. 10 Fr). Large and infected collections may benefit from placement of a nasocystic drain and regular irrigation. Given the significant risk of aspiration, endotracheal intubation for the procedure is recommended, particularly for larger collections that are more likely to decompress rapidly. Additionally, CO₂ insufflation is preferred to air to minimize the risk of air embolism. The utility of multiple stents is to facilitate flow of fluid around and between stents. The stents are generally removed after a minimum of six weeks. There is some evidence that recurrence rate is inversely related to indwelling time. If a disconnected pancreatic duct is identified on secretin‐stimulated MRCP or ERCP, the stents can be left in place indefinitely. Fully covered self‐expanding metal stents can be used. Initially, biliary metal stents were repurposed. More recently, the advent of lumen‐apposing metal stents (LAMS) delivered through an electrocautery‐tipped delivery platform specifically designed for EUS‐guided deployment has greatly simplified the process of endoscopic drainage of pancreatic fluid collections. The placement of LAMS has significantly shortened procedure time, reduced the requirement for skilled assistants, and obviated the need for fluoroscopy. Moreover, at least theoretically, the large‐diameter, lumen‐apposing, wide flange stent design has enhanced not only the drainage efficacy of the device but also overall safety of the procedure, potentially minimizing the risk of perforation and pseudocyst wall dehiscence in the setting of indeterminate adherence to the gastroduodenal wall. However, LAMS have several disadvantages compared to plastic stents, including substantially higher cost, greater risk of delayed bleeding (particularly when left in situ for more than three weeks), and requirement for subsequent exchange for long‐term plastic stents in the subgroup of patients with disconnected pancreatic duct syndrome who would otherwise be at risk of pseudocyst recurrence. There are as yet no randomized controlled trials comparing LAMS and plastic stents in the management of pseudocysts. Available data is conflicting in terms of overall clinical success and adverse event rates [11–13]. However, plastic stents do appear to be more cost‐effective whilst LAMS have been associated with a higher risk of bleeding [12] (Figure 17.2).

Figure 17.2 CT scan showing LAMS in situ.

Source: courtesy of Muhammad F. Dawwas and Kofi W. Oppong.

Transpapillary drainage of pancreatic pseudocysts by means of stent placement in the pancreatic duct is potentially feasible in the subgroup of patients with small to moderate‐sized pseudocysts that clearly communicate with the main pancreatic duct. In this setting, the pancreatic duct is cannulated via the major or minor papilla in the standard fashion and the disrupted segment of the duct is bridged with one, or preferably two, plastic stents after undertaking a pancreatic sphincterotomy. If this is not feasible, placement of the stent tip medial to the leak or within the pseudocyst may also be effective. In practice, however, transpapillary drainage is not recommended as sole drainage therapy for the majority of pancreatic pseudocysts for several reasons. First, given the fact that at least 50% of pancreatic pseudocysts develop in the absence of evidence of disruption of the main pancreatic duct, transpapillary stent placement in this setting would not be anticipated to facilitate effective drainage. Second, undertaking ERCP in the setting of extrinsic luminal compression of the gastroduodenal lumen and gross inflammation of the duodenal mucosa can be technically challenging, as would attempts to stent a disrupted duct lateral to an obstructing stone or high‐grade stricture. Third, preoperative evaluation of the integrity of the main pancreatic duct may not be feasible as a result of unavailability of a high‐quality secretin‐stimulated MRCP service. Last, the smaller diameter of both pancreatic stent and pancreatic duct, compared with the diameter of transluminal stents and fistula, may result in inadequate drainage, increasing the risk of infection in the setting of contrast contamination of an otherwise sterile pseudocyst.

Combined transluminal and transpapillary drainage is favored by many experts, although the evidence base supporting this practice is less than compelling. If ERCP is performed, the timing of the procedure is also controversial. Undertaking ERCP prior to transluminal pseudocyst drainage may be accompanied by multiple technical challenges as already outlined. On the other hand, delaying ERCP may potentially result in missing a valuable window of opportunity for stenting a potentially bridgeable pancreatic duct disruption that, in the absence of intervention, may evolve into a non‐traversable, high‐grade stricture or even a disconnected duct.