ERCP and EUS for Acute and Chronic Adverse Events of Pancreatic Surgery and Pancreatic Trauma

Anatomy

The classic Whipple operation involves removal of the pancreatic head, pancreatic neck, gastric antrum, duodenum, 20 cm of proximal jejunum, gallbladder (if present), distal common bile duct, and regional lymph nodes. There are two side-to-side enteroenterostomies visible from the gastric remnant ( Fig. 45.1 ). The afferent limb, which is usually 40 to 60 cm long, ascends superiorly and ends blindly with an end-to-end or end-to-side pancreaticojejunostomy. An end-to-side choledochojejunostomy is usually located 10 cm distal to the end of the afferent limb and along the antimesenteric border, often behind a mucosal fold.

Pylorus-preserving pancreaticoduodenectomy (modified Whipple surgery) is performed to maintain gastric function. The entire stomach is preserved and a cuff of the duodenal bulb remains ( Fig. 45.2 ). Upon exiting the stomach, a duodenal stump is encountered with two end-to-side enteroenterostomies, with one leading to the afferent limb containing the biliary and pancreatic anastomoses ( Fig. 45.3 ). The location of the afferent limb within the visual field is not uniform and also is dependent on the type of endoscope used (side-viewing vs forward-viewing).

Role of Endoscopy in the Management of Adverse Events

Endoscopy plays a very limited role in the management of acute postoperative adverse events after Whipple surgery. Pancreatic leaks, although reported to occur in up to 20% of Whipple surgeries, are managed by percutaneous drainage, administration of octreotide, and intravenous hyperalimentation. However, endoscopy plays a significant role in the management of delayed pancreaticobiliary strictures and/or stones ( Box 45.2 ). The necessity of endoscopic intervention is decided with the aid of abdominal computed tomography (CT) or magnetic resonance cholangiopancreatography (MRCP) with or without secretin.

Before embarking on endoscopy, it is imperative to plan, which includes choice of endoscope, accessories, patient position, and need for anesthesia support, so that optimal outcomes can be achieved in this subset of patients ( Box 45.3 ; see also Chapter 10 ).

In classic Whipple anatomy, the biliary anastomosis can occasionally be reached with a standard duodenoscope. The side-viewing endoscope offers the technical advantages of an en face view of the anastomosis and presence of an elevator to assist with control of accessories. However, the success rate in accessing the pancreatic anastomosis is suboptimal at best. A widely patent anastomosis is seen in Fig. 45.4 .

Commonly the approach using a side-viewing endoscope results in failure to reach either the biliary or the pancreatic anastomosis because of the insertion tube length. This is especially true in patients with pylorus-preserving anatomy and longer afferent limbs. In these cases, the procedure may be accomplished with a colonoscope. Therapeutic channel colonoscopes allow placement of 10-Fr plastic biliary stents, though the rigidity can prevent negotiating angulated, fixed afferent limbs. Some biliary self-expandable metal stents can be passed through colonoscopes (both pediatric and adult). Absence of an elevator can make it challenging to maneuver accessories and accomplish therapeutic interventions.

Various other techniques can be employed to gain access to the end of the afferent limb and the biliopancreatic anastomosis ( Box 45.4 ).

There are now robust data on the use of single-balloon enteroscopes, double-balloon enteroscopes, and rotational overtube endoscopes to allow technical success for accessing biliary and pancreatic anastomoses. These procedures are most often performed by experienced endoscopists at tertiary care centers when ERCP failure is caused by inability to reach the anastomosis with standard endoscopes. Balloon-assisted ERCP is often time-consuming and difficult because of the limited availability of compatible accessories. On the contrary, endoscopic ultrasonography (EUS) has gained popularity in the management of delayed pancreatobiliary complications in post–pancreatic surgery patients.

Bilioenteric Anastomotic Stricture

Bilioenteric anastomotic strictures can be benign or malignant as a result of recurrent disease such as pancreatic cancer, primary sclerosing cholangitis, or autoimmune disease. Distinguishing between the two can be extremely difficult because of submucosal tumor invasion. Treatment of these strictures is undertaken as for other benign ( Fig. 45.5 ) and malignant strictures, although the options can be limited by the endoscope length and channel diameter. In some cases, needle-knife entry can be undertaken, though this carries risk of perforation.

In patients in whom the biliary anastomosis cannot be reached, EUS has been used for antegrade placement of plastic and self-expandable metal stents. More recently, lumen-apposing metal stents (LAMS) have been deployed under EUS guidance for management of bilioenteric anastomotic stricture.

Afferent Limb Obstruction

Afferent limb obstruction is often caused by recurrent tumor, usually occurring at the ligament of Treitz, but can also occur from radiation therapy. Such downstream obstruction most commonly presents with obstructive jaundice or cholangitis. Other presenting symptoms include abdominal pain, nausea, and vomiting. The most common endoscopic findings are malignant or benign luminal stricturing of the afferent limb, severe angulation of or fixed afferent limb, and mucosal changes of friability, ulceration, and telangiectasia from radiation enteropathy. Endoscopic interventions performed for management include placement of plastic and self-expandable metal stents in the afferent limb and/or obstructed bile duct. EUS-guided management of afferent limb obstruction using lumen-apposing stents is an alternative to traditional luminal stent placement in post–Whipple surgery patients.

Efferent Limb Obstruction

Recurrent malignancy is the most common cause of efferent limb obstruction, followed by adhesions and radiation-induced strictures. The most common presenting symptoms are similar to afferent limb obstruction plus features of gastric outlet obstruction. Self-expandable metal stents (SEMS) can be placed for efferent obstruction alone or combined with stent placement in both the afferent and efferent limbs. Although not reported, it may be feasible in some patients to perform EUS-guided gastrojejunostomy of the efferent limb using LAMS.

Miscellaneous

Miscellaneous causes of biliary obstruction include stones and sludge and retention or migration of surgically placed stents into the biliary tree.

In patients with failed retrograde endoscopic access, EUS has been successfully used for management of biliary stones in the hepatic duct using an antegrade approach.

Other Treatment Options for Biliary and Pancreatic Ductal Obstruction

More recently, there have been reports of use of combined modalities.