27 PANCREATIC AND DUODENAL INJURY
Caesar M. Ursic M.D.

1. How common are pancreatic injuries?

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The pancreas is not commonly injured because of its protected retroperitoneal position, and thus accounts for only 8% of all penetrating and 2% of all blunt visceral injuries.

2. What other injuries are typically associated with penetrating pancreatic trauma?

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Liver injury is the most frequent concomitant injury, with a reported incidence of ≤ 50%. Other commonly associated injuries include the stomach (40%), large abdominal vessels such as the aorta and vena cava (40%), spleen (25%), kidneys (2%), and duodenum (20%).

3. How are pancreatic injuries diagnosed and staged preoperatively?

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Preoperatively, computed tomography with intravenous contrast enhancement may actually demonstrate a transected pancreas or major destruction of portions of the gland and has a high positive predictive value; however, it suffers from a low negative predictive value (i.e., it may miss even big injuries). Ultrasound does not consistently image the retroperitoneum adequately and is often hampered by overlying bowel gas. Elevated serum amylase concentrations are nonspecific for pancreatic injury and can be normal in a high proportion of patients shown subsequently to harbor significant injuries to the gland. Diagnostic peritoneal lavage is also unreliable. Short of mandatory exploration, there are no universally reliable methods to assure early diagnosis of significant pancreatic injuries. Surgeons must pay particular attention to the mechanism of injury and subtle signs and symptoms of the physical examination and combine them with data obtained from imaging studies.

4. What are some of the commonly used surgical options for the treatment of pancreatic injuries?

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Most low-grade penetrating and blunt injuries to the pancreas are adequately treated by closed suction drains placed at surgery. First, the integrity of the main pancreatic duct should be evaluated, either by direct inspection or by intraoperative pancreatography. Distal duct injuries (defined as those occurring to the left of the superior mesenteric vessels) are treated with distal pancreatectomy, with or without splenectomy, and closed drainage of the pancreatic stump. Preservation of the spleen is preferable. Injuries to the proximal portion of the gland that do not involve the main duct are treated with closed suction drainage. Injury to the pancreatic duct in the head or neck of the pancreas may require resection of significant portions of distal pancreas. If more than 80% of the gland is removed, the risk of endocrine and exocrine pancreatic insufficiency is high. Try to preserve distal glandular tissue by incorporating it into a Roux-en-Y pancreaticojejunostomy. With severe pancreatic head destruction, instances involving significant injuries to the duodenum and distal biliary structures may require a pancreaticoduodenectomy (i.e., Whipple procedure). Recent reports of successful nonoperative management of complete pancreatic transections in pediatric patients may shift the approach to these injuries away from resection, although the current standard of care remains surgical.

KEY POINTS: SURGICAL OPTIONS FOR PANCREATIC INJURIES

1. Low-grade injuries are treated with simple closed suction drainage at the time of celiotomy.
2. In unstable patients, debride, obtain hemostasis, and drain. Deal with the resultant fistula at a later time.
3. If ductal injury is suspected in a stable patient, visualize with ERCP or cholangiogram.
4. If ductal injury is present in the head or neck of the pancreas, ligate proximally and attempt to preserve pancreatic tissue with Roux-en-Y pancreaticojejunostomy.
5. Always place a jejunal feeding tube.

5. Is an elevated serum amylase level diagnostic of pancreatic trauma?

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No. Up to 40% of patients who have sustained significant pancreatic injury do not show elevations in their initial serum amylase level. There appears to be a slightly higher positive predictive value if the elevated amylase level is obtained more than 3 hours after the patient’s injury, although elevated amylase is common with trauma not involving the pancreas. Up to 40% of patients sustaining isolated head trauma can present with serum hyperamylasemia, which is unrelated to pancreatic injury.

6. How do blunt pancreatic injuries differ in children and adults?

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Adult pancreatic injury is usually either penetrating (e.g., stab and gunshot wounds) or high-speed blunt forces (e.g., motor vehicular crashes). Children usually present after direct blows to the epigastrium, typically from bicycle handlebars, which compress the pancreas between the anterior surface of the thoracic spine and the handlebar, often resulting in complete glandular transection.

7. What is the optimal route of nutritional supplementation after a major pancreatic injury?

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Direct feeding into the stomach is contraindicated because it stimulates pancreatic exocrine secretion and aggravates healing, potentiating secondary pancreatitis and pancreatic fistulas formation. Postpyloric enteral nutrition can be delivered safely and effectively via a feeding jejunostomy tube placed at the completion of the abdominal exploration and pancreatic repair.

8. Describe the common complications of pancreatic injuries.

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Complications are common. The two most common are pancreatic fistulas and intraabdominal abscesses. Other problems are pancreatitis, pancreatic pseudocyst, and pancreatic hemorrhage. Most patients who die after sustaining injuries to the pancreas do so as a result of late complications and not from the pancreatic injury itself.

9. What is the role of computed tomography (CT) scanning in diagnosing blunt duodenal injuries?

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Although CT is an excellent tool for visualizing solid organ injuries, CT is less useful with injuries to hollow organs such as the duodenum. Even the addition of an oral contrast agent to the study does not seem to improve the diagnostic yield. Subtle signs of duodenal injury on CT scans include periduodenal edema or fluid and retroduodenal air, which usually indicates a duodenal rupture and spillage of small amounts of intralumenal contents into the retroperitoneum.

10. What is the importance of the Kocher maneuver?

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In 1903, Kocher described what has now become a routine maneuver during the exploratory celiotomy to visualize and repair injuries to the duodenum, distal common bile duct, and pancreatic head. The avascular lateral peritoneal attachments to the duodenum are incised sharply; then the duodenal sweep is elevated and reflected medially, allowing for inspection and palpation of its posterior surface as well as of the head of the pancreas.

11. What are the four portions of the duodenum and their surgical relationships?

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The first portion of the duodenum starts at the pylorus (intraperitoneally) and passes backward (retroperitoneally) toward the gallbladder (the remainder of the duodenum is retroperitoneal). The second portion descends 7-8 cm and is anterior to the vena cava. The left border of the duodenum is attached to the head of the pancreas, at the site where the common bile and pancreatic ducts enter; it shares a common blood supply with the head of the pancreas through the pancreaticoduodenal arcades. The third portion of the duodenum turns horizontally to the left, with its cranial surface in contact with the uncinate process of the pancreas, and passes posterior to the superior mesenteric artery and vein. The fourth portion continues to the left, ascending slightly and crossing the spine anterior to the aorta, where it is fixed to the suspensory ligament of Treitz at the duodenojejunal flexure.

12. How are duodenal injuries classified?

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An organ injury scale has been adopted that allows for standardized descriptions of duodenal injuries, which extend from grade I (least severe) to grade V (most severe). The grading of duodenal injuries assists surgeons in selecting the appropriate surgical procedure for the repair or reconstruction of these frequently complex injuries. (See Table 27-1).
Table 27-1. GRADES OF PANCREATIC INJURY

D1, D2, D3, and D4 refer to the portions of the duodenum (i.e., first through fourth).

13. What are the main surgical options for penetrating duodenal injuries?

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Most simple lacerations can be repaired primarily. Complex lacerations with devitalized margins or lacerations that involve > 50% of the duodenal circumference require debridement of margins and re-anastomosis of the divided ends. If tension on the suture line is anticipated because of extensive tissue loss, adjunctive techniques such as Roux-en-Y duodenojejunostomy or pyloric exclusion are more appropriate. Protection of a duodenal repair is best assured by a tube duodenostomy and generous external drainage. With severe duodenal injury that involves distal biliary structures and the pancreatic head, a pancreaticoduodenectomy (i.e., Whipple procedure) may be the most appropriate option.

References
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BIBLIOGRAPHY
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