Duodenal Diverticula

See Small Bowel Diverticular Disease for the true/false diverticula overview. Content below is from a textbook reference chapter (Sabiston Ch50 - Diverticular Disease & Miscellaneous Problems), not primary literature.

Incidence and cause

First described by Chomel (French pathologist) in 1710. Duodenal diverticula are relatively common, representing the second most common site for diverticulum formation after the colon. Incidence varies by diagnostic method: upper GI radiographic studies identify duodenal diverticula in 1–5% of studies, whereas ERCP identifies 9–23% of cases; autopsy series report an incidence of approximately 15–20%. Occur twice as often in women as in men, and are rare in patients younger than 40.

Classified as congenital or acquired, true or false, and intraluminal or extraluminal:

• Extraluminal duodenal diverticula are considerably more common than intraluminal — acquired, mucosal or submucosal outpouchings herniated through a muscle defect in the bowel wall. Usually occur in the second portion of the duodenum (62%), less commonly the third (30%) and fourth (8%) portions; rarely the first part (<1%). When they occur in the second portion, most (88%) are noted on the medial wall around the ampulla (periampullary), 8% posteriorly, and 4% on the lateral wall.
• Intraluminal duodenal diverticula (also known as windsock diverticula) are congenital and occur as a single saccular structure connected to the entire circumference or part of the wall of the duodenum, creating a duodenal web. Result from incomplete recanalization of the duodenum during fetal development — exceedingly rare.

Clinical manifestations

The overwhelming majority of duodenal diverticula are asymptomatic and usually noted incidentally on an upper GI series (Fig. 50.39). Upper GI endoscopy identifies approximately 75% of duodenal diverticula, and use of a side-viewing scope further increases the success rate. Plain abdominal films may show an atypical gas bubble. CT can identify large diverticula by a mass-like structure interposed between the duodenum and pancreatic head containing air, air-fluid levels, fluid contrast material, or debris. MRCP is particularly helpful for demonstrating the relationship of the diverticulum to the biliary/pancreatic ducts and associated pathologic changes. Hemorrhage in diverticula is best diagnosed by a combination of angiography and 99mTc-labeled red blood cell scan; surgery should not be delayed to obtain imaging in a hemodynamically unstable patient.

Less than 5% of duodenal diverticula require surgery because of a complication from the diverticulum itself. Major complications: obstruction of the biliary or pancreatic ducts (may contribute to cholangitis and pancreatitis), hemorrhage, perforation (rare), and — rarely — blind loop syndrome. Iatrogenic injuries, most commonly acquired during endoscopic instrumentation of an asymptomatic diverticulum, can result in perforation or hemorrhage.

Only diverticula associated with the ampulla of Vater are significantly related to complications of cholangitis/pancreatitis — in these patients, the ampulla usually enters the duodenum at the superior margin of the diverticulum rather than through the diverticulum itself. A proposed etiology for biliary tract complications is the perivaterian diverticulum’s location, which may distort the common bile duct as it enters the duodenum, causing partial obstruction and stasis. Hemorrhage can be caused by inflammation leading to erosion of a branch of the superior mesenteric artery. Perforation of duodenal diverticula has been described but is rare. Finally, stasis of intestinal contents within a distended diverticulum can cause bacterial overgrowth, malabsorption, steatorrhea, and megaloblastic anemia — essentially producing a blind loop syndrome. Symptoms related to duodenal diverticula in the absence of any other demonstrable disease are usually nonspecific epigastric complaints that can be treated conservatively and may actually prove to be the result of another problem not related to the diverticulum itself.

Treatment

Most duodenal diverticula are asymptomatic and benign; when found incidentally, they should be left alone. For symptomatic duodenal diverticula, treatment consists of removal, accomplished endoscopically or surgically. Appropriate classification of these diverticula guides management.

• Intraluminal diverticula always require treatment, since recurrence of symptoms is certain. Curative treatment is removal of the intraluminal diverticulum by laparotomy and duodenotomy, or by endoscopic resection. A large (>3 cm) or obstructing diverticulum does not preclude endoscopic resection, but an endoscopic approach in the setting of massive hemorrhage or perforation with intraabdominal contamination secondary to intestinal contents is discouraged — these entities are relatively rare and often require a multidisciplinary approach.
• Extraluminal diverticula should be resected in the setting of symptomatic disease or need for urgent surgery (free perforation or hemorrhage). The most common and effective treatment is diverticulectomy, most easily accomplished via a wide Kocher maneuver exposing the duodenum; the diverticulum is excised, and the duodenum closed in a transverse or longitudinal fashion, whichever produces the least luminal obstruction. Careful identification of the ampulla is essential to prevent injury to the common bile duct and pancreatic duct. For diverticula embedded deep within the head of the pancreas, a duodenotomy is performed, with invagination of the diverticulum into the lumen, which is then excised, and the wall is closed (Fig. 50.40A–C). Alternative methods for diverticula associated with the ampulla of Vater include an extended sphincteroplasty through the common wall of the ampulla in the diverticulum (Fig. 50.40D–F). Laparoscopic duodenal diverticulectomy is safe and effective in patients with symptomatic and noncomplicated (not perforated or bleeding) diverticula — an endoscopic stapler is most commonly used to traverse and resect the diverticulum at its base, with an omental patch reinforcement placed over the staple line.
• Perforated diverticulum: treatment may require procedures similar to those for massive trauma-related defects of the duodenal wall. The perforated diverticulum should be excised and the duodenum closed with a serosal patch from a jejunal loop. If surrounding inflammation is severe, it may be necessary to divert enteric flow away from the perforation site with a gastrojejunostomy or duodenojejunostomy. Interruption of duodenal continuity proximal to the perforated diverticulum may be accomplished by pyloric closure with suture or a row of staples. If the diverticulum is posterior and perforates into the substance of the pancreas, operative repair may be difficult and dangerous — wide drainage with duodenal diversion may be all that is feasible. Great care should be taken if the perforation is adjacent to the papilla of Vater. Surgical jejunostomy should also be considered for all patients with acute perforation to ensure nutrition repletion.

Open items / gaps

• No primary literature yet in the wiki on duodenal diverticula — entirely textbook-reference-derived.