A frequent feature of chronic pancreatitis is unremitting abdominal pain that is multifactorial in etiology, but is believed to develop in part due to pancreatic ductal hypertension resulting from outflow obstruction. The pancreatic ductal hypertension is a sequela of parenchymal destruction, inflammation, and pathological fibrosis resulting in benign strictures of the main PD, papillary stricture, PD stones, rupture of the main PD, or a combination of these. Endoscopic therapy in chronic pancreatitis can provide benefit by decompressing the PD with stricture dilation, stent placement or stone fragmentation or removal.

Disconnected PD syndrome is a recognized complication of acute necrotizing pancreatitis, chronic pancreatitis, and abdominal trauma that results in a rupture of the main PD and viable pancreas secretions failing to drain into the gastrointestinal tract. Extravasated pancreatic secretions from a disconnected duct can result in complications including high-amylase ascites and pleural effusions, internal or external fistulas, and pseudocysts. Transpapillary stenting in conjunction with continued medical therapy has been reported to be successful in 55% to 84% [4-6] of patients, whereas surgical therapy, often a distal pancreatectomy, carries a relatively high morbidity and mortality. Percutaneous rendezvous therapies for PD duct disruption have been described, but are not routinely used [7]. EUS-PDD has been reported to be successful in cases of chronic pancreatitis with complete rupture of the main PD [2] and in cases of PD leaks.

Cannulation of the PD via the major papilla has a high success rate, recently reported to be between 90% to 98% [8]. Failure of selective PD cannulation can occur due to an inability to identify the major papilla, stenosis after endoscopic biliary sphincterotomy or surgical sphincteroplasty, ampullary adenoma or tumor obscuring papillary visibility, history of ampullectomy, distorted gastric or duodenal anatomy, and/or peridiverticular papilla location. The first EUS-guided rendezvous technique for PD access was reported in a patient with a peridiverticular, previous biliary sphincterotomy and a suprapapillary stricture that precluded ERP despite multiple attempts in 2002 [9].

While accessing the PD can be achieved with both, small caliber 25- and 22-, and larger caliber 19-gauge needles, the indication for PD access, the degree of PD dilation and the presence of pancreatic parenchymal changes should all be taken into account [16,17]. For example, in dilated PDs (>5 mm) or for the placement of transluminal stents, the use of a 0.035 inch guidewire, which requires a 19-gauge needle, is most appropriate and frequently the instrument of choice. However, the larger 19-gauge needle may change the angle of the linear echoendoscope probe and might be more difficult to pass through a fibrotic pancreas. For pancreatography, smaller caliber needles can provide similar access with less risk of complications including leakage, bleeding or postprocedure pancreatitis [18].

In the largest case series of EUS guided PD stent placement for drainage reported by Fujii et al. [19] (43 patients, 32 with technical success), a 19-gauge fine needle aspiration (FNA) needle (Cook Medical, Bloomington, IN, USA) was used for duct access. The second largest case series by Tessier et al. [2] (36 patients, 33 with technical success) included either a 19- or 22-gauge FNA needle (EUS-19-T or ECHO-1-22; Cook Medical), or inner needle of a cystoenterostome (Cystostome CST10; Cook Medical).

Similar to needle selection, the choice of guidewire should be tailored by their inherent properties (including stiffness, fluoroscopic and endoscopic visibility, and ease of over-the-wire instrument exchange) and by the goals of the procedure. Transanastomotic or transampullary PD stenting and rendezvous procedures often require a stiffer, hydrophilic wire/tip such as a 0.025 or 0.035 inch angled, or straight Visiglide (Olympus America, Center Valley, PA, USA) to bypass the anastomosis or ampulla with minimal kinking. The main benefit of utilizing smaller caliber 0.021 or 0.018 inch wires with either a 19- or 22-gauge needle is their flexibility, which can aid in maneuvering the wire though a tortuous duct and/or bypassing ductal strictures. Unfortunately, these small wires often have reduced radiographic opacity, and the lack of stiffness makes over-the-wire instrument exchange and maintenance of the wire position more challenging. At the cost of reduced flexibility and increased PD insertion difficulty, stiff larger wires provide access that is associated with less kinking, increased fluoroscopic visibility, and increased stability for ease of subsequent instrument passage. This has led some experts to recommend transitioning from a 0.018 or 0.020 inch guidewire to a larger, stiffer wire (0.035 inch) in preparation for stenting or rendezvous [18]. Along these lines, in the Tessier et al. [2] case series, when a smaller wire (0.020 inch) was used, it was subsequently exchanged for a larger 0.035 inch wire. In the Fuji et al. [19] case series, either a 0.035 or 0.025 inch, both straight and angled hydrophilic versions (Glidewire, Jagwire; Boston Scientific, Natick, MA, USA) were used.

EUS guided antegrade PD stenting requires the bowel luminal (gastric, duodenal, or jejunal)-PD fistula tract to be dilated after needle puncture and wire insertion. A wide array of endoscopic tools including hydrostatic balloons (Titan biliary dilation Balloon, Cook Medical; or 4 mm, Hurricane Biliary Dilation Balloon, Boston Scientific), tapered catheters (5- to 7-Fr, Sohendra; Cook Medical), cannulas (Proforma; Conmed Endoscopic Technologies, Utica, NY, USA), and/or diathermic catheters such as a needle knives can be used to dilate the tract [19]. To date, there have been no comparative trials to evaluate the success and complication rates of tract dilation methods. The use of diathermic catheters remains controversial. Multiple experts recommend their use as a last resort because of concerns of cautery-related adverse events [18,20], while others have reported personal experience with less peripancreatic juice leak relative to balloons [21]. Endoscopists, therefore, tend to rely upon personal experience when deciding what equipment to use and often, multiple devices are serially employed.

PD stents that have been used include straight as well as single and double pigtail stents. In the largest case series from Japan, 7 and 5 Fr plastic stents were most commonly used with single cases of an 8 mm self-expandable metal stent and 5 Fr naso-PDD (with subsequent exchange to a 7 Fr plastic stent) [15]. Stent dysfunction can occur either through migration or occlusion, and although not statistically significant, stent migration occurred more frequently with straight plastic stents than with double pigtail plastic stents in one of the largest studies on EUS-PDD [20]. Recently, a new, single pigtail 7-Fr plastic stent was developed specifically for EUS-guided PD placement by Itoi et al. [22]. The stent has a tapered tip, four internal flanges (two in the distal end and two at the proximal end), and a single external pigtail (total length of 20 cm and effective length of 15 cm). The initial feasibility report of eight patients achieved technical and treatment success in 100% of cases.

Covered metal stents were initially not recommended for use due to concerns of PD obstruction; however, Oh et al. [23] recently described EUS-PDD using a novel fully covered self-expandable metal stent (FCSEMS) with anti-migration properties in 25 patients with “painful obstructive pancreatitis” after failed ERP. This modified FCSEMS (commercially available, silicone coated, nitinol wire, 6 or 8 mm diameter, 6 to 10 cm in length; M.I. Tech, Seoul, Korea) with proximal and distal anchoring flaps was placed into either a pancreatogastric or pancreatoenteric fistula. EUS-guided pancreatogastrostomy (n=23), pancreatoduodenostomy (n=1), and pancreatojejunostomy (n=1) were performed. EUS-PDD had 100% technical and clinical success rates. Pain scores improved significantly after FCSEMS placement (p=0.001). Early mild grade adverse events occurred in five patients (20%), four with self-limited abdominal pain and one with minor bleeding.

In 2015, Fujii-Lau and Levy [20] summarized the current literature on EUS-guided PD drainage, reviewing the published experience of 222 patients. Including both antegrade and rendezvous techniques, technical success was achieved in 170/222 patients (76.6%). A similar review by Itoi et al. [18] in 2013 reported a technical success rate of >70% in 75 patients using the antegrade technique and a range of success rates from 25% to 100% in 52 patients with the rendezvous technique. The largest experience in the rendezvous cohort was 20 patients with a lower reported technical success rate of 48%.

In the largest series of attempted EUS guided PD stent placement, which involved 43 patients, technical success occurred in 32 patients (74%), with 18 undergoing antegrade EUS-PDD (13 transpapillary or transanastomotic vs. five transluminal) and 14 undergoing retrograde/rendezvous EUS-PDD [19]. ERP performed during the same procedure was the only statistically significant factor associated with failure of stent placement. Long-term outcomes (defined as a minimum 1 year of follow-up) were available for 29 patients. Complete clinical success defined as all symptom resolution occurred in 69.6% and partial symptom resolution (improved severity or frequency of symptoms) was found in the remaining 30.4%. In a 12 patient case series, 29% of patients underwent surgery within a follow up range of 4 weeks to 3 years [25].

In the recently published summary of available EUS-PDD case series, complications were documented in 42 of 222 patients (18.9%) [20]. The most frequent complication was abdominal pain occurring in 17 patients (7.7%) followed by pancreatitis in seven patients (3.2%). Additional less frequently reported complications included four patients with bleeding, two patients each with perforation, peripancreatic abscess, or shearing of the guidewire. A single patient was reported to develop fever, pneumoperitoneum, pseudocyst, aneurysm, or perigastric fluid collection. In the largest published, single center experience, the adverse event rate was lower at 6%, with one episode of pancreatitis requiring an 11 day admission, one abscess requiring EUS drainage, one retained sheared wire, and 13 patients with abdominal pain requiring admission (median length of stay, 2 days) [19].

Stent dysfunction, defined as migration or occlusion, has been reported to occur in 25% [19] to 55% of cases [2,26]. In the case series by Fujii et al. [19], stent dysfunction occurred in eight patients (25%) including five cases of stent migration, of which four of five occurred with straight plastic stents. Although not statistically significant, migration occurred in 23% of straight stents compared to 9% of double pigtail stents, leading the endoscopists to favor the use of double pigtail stents [19].