Pancreatic trauma: Demographics, diagnosis, and management

Invited Commentary

Pancreatic Trauma: Demographics, Diagnosis, and Management STANISLAW PETER STAWICKI, M.D., C. WILLIAM SCHWAB, M.D.

From the Department of Surgery, Division of Traumatology and Surgical Critical Care, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania

Pancreatic injuries are rare, with penetrating mechanisms being causative in majority of cases. They can create major diagnostic and therapeutic challenges and require multiple diagnostic modalities, including multislice high-definition computed tomography, magnetic resonance cholangiopancreatography, endoscopic retrograde cholangiopancreatography, ultrasonography, and at times, surgery and direct visualization of the pancreas. Pancreatic trauma is frequently associated with duodenal and other severe vascular and visceral injuries. Mortality is high and usually related to the concomitant vascular injury. Surgical management of pancreatic and pancreaticduodenal trauma is challenging, and multiple surgical approaches and techniques have been described, up to and including pancreatic damage control and later resection and reconstruction. Wide surgical drainage is a key to any surgical trauma technique and access for enteral nutrition, or occasionally parenteral nutrition, are important adjuncts. Morbidity associated with pancreatic trauma is high and can be quite severe. Treatment of pancreatic trauma-related complications often requires a combination of interventional, endoscopic, and surgical approaches.

occur infrequently after blunt P or penetrating abdominal trauma, with the reported incidence of pancreatic injury between 5 and ANCREATIC INJURIES

7 per cent of all abdominal injuries.1, 2 Isolated pancreatic injury is even less common due to the retroperitoneal location of the pancreas and the proximity of multiple organs and major vascular structures.3 Overall, most pancreatic injuries are due to penetrating mechanism (70–75%), which carries the highest overall incidence of pancreatic injury (12%).4 Pancreatic injuries constitute a major diagnostic challenge and often a therapeutic challenge. The frequent lack of familiarity with pancreatic trauma combined with the diagnostic difficulties faced by even the Address correspondence and reprint requests to Stanislaw Peter Stawicki, M.D., Division of Traumatology and Surgical Critical Care, 3400 Spruce Street, Philadelphia, PA 19104. E-mail: [email protected]. Editor’s Note: Dr. Stawicki recently completed a trauma fellowship at the University of Pennsylvania and is presently in the Department of Surgery, Division of Critical Care, Trauma, and Burn at the Ohio State University Medical Center in Columbus, Ohio. Dr. William Schwab is the Chief of the Division of Trauma at the Hospital of the University of Pennsylvania in Philadelphia and is a nationally recognized leader in the care of the injured.

most experienced practitioners can pose unique challenges across the spectrum of age groups and traumatic mechanisms.5 However, some generalizations can be made. First, blunt pancreatic injuries are more common in children. These usually occur from crushing the duodenum and pancreas between the spine and a blunt object such as a handlebar or some other severe force applied to the upper/midabdomen. Stomping and striking the midepigastrium are common mechanisms (Fig. 1).6 Second, pancreatic injury due to penetrating mechanisms is more common in adults, especially after abdominal gunshot wounding. Mortality rates associated with pancreatic injury in the setting of penetrating trauma vary from 13 per cent to over 30 per cent, with most deaths related to associated injuries, in particular vascular injury.7 Important factors that influence the occurrence and severity of pancreatic trauma include more common seat belt usage for blunt injuries and changes in firearms, especially semiautomatic handguns, resulting in greater number of wounds and more severe injuries. Because the duodenum encases the head of the pancreas, any discussion of pancreatic injury must include concomitant review of duodenal injury and its management.8, 9

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FIG. 1. Common mechanisms of pancreatic injury: (A) Application of direct linear pressure to the upper abdomen—seen in falls from height onto a linear structure or in seatbelt injuries; (B) Application of direct focal pressure to the upper abdomen—seen in bicycle handle injuries and other traumatic mechanisms that lead to application of large amounts of force to localized upper abdominal area; (C) Blunt assault with direct focal injury to the upper abdomen; (D) Steering-wheel injury to the upper abdomen.

Anatomy

Detailed knowledge of anatomic relationships between the pancreas and surrounding structures is crucial when approaching patients with suspected pancreatic injury.10 The retroperitoneal location of the pancreas offers some physical protection to the gland, but also contributes to greater diagnostic difficulty.4 This anatomy must also be carefully integrated with the mechanism of injury, and correlated with radiographic and other diagnostic tests. The pancreas lies just posterior and inferior to the stomach. It is closely related to the duodenum, with the first through third portions of the duodenum surrounding the pancreatic head and the fourth portion related more closely to the neck and body of the gland. The tail of the pancreas is in close proximity to the left kidney and the spleen, with a relationship to the splenic blood supply. Posterior to the pancreas is the vertebral column. This is significant when approaching a patient with a “seat belt” sign after a motor vehicular crash—a sign highly associated with pancreatic contusion or fracture

secondary to the compression of the pancreas between the restraining device and the spine.11 The pancreas can be divided anatomically into three distinct “zones” based on both intrinsic and extrinsic landmarks—head, body, and tail (Fig. 2). This is important because treatment of pancreatic injuries is de-

FIG. 2. Regional anatomy of the pancreas—the three pancreatic regions include the head/uncinate process; the neck/body; and the tail.

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pendent on their anatomic location. The head of the pancreas is to the right of the mesenteric and portal vessels, in a close and complex relationship with the duodenum, the common bile duct, and the pancreatic duct. The right kidney, the right adrenal, and the inferior vena cava are all in close proximity to the pancreas and the duodenum, and can be injured in association with pancreatic trauma. The stomach, colon, small intestine, and liver are located anterior to the pancreas. Blood supply to the pancreas is complex, and makes operative management of pancreatic injuries difficult. In addition to multiple collateral arterial systems supplying the pancreas, these arterial arcades are also shared with the adjacent retroperitoneal and peritoneal organs, including the duodenum, the spleen, the stomach, and the hepatobiliary structures (Fig. 3). Associated abdominal organ injury and severe vascular injury are frequently found as part of the overall injury constellation. Over 90 per cent of pancreatic injuries have an associated intra-abdominal injury,

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with liver, stomach, and major blood vessels being the most common; an average of three or more intraabdominal organs are injured.10 The multitude of blood vessels around the pancreas include the aorta, inferior vena cava, the portal vein, the superior mesenteric artery and vein, left renal pedicle, splenic artery and vein, gastro duodenal and gastroepiploic arteries, to name only the larger. Vascular injury accounts for over 50 per cent of the fatal cases.7 Among gunshot wounds, 50 to 75 per cent have a major vascular injury, commonly the aorta, portal vein, and the inferior vena cava. The proximity of major vascular structures and the duodenum significantly increases the morbidity of missed injury.4 Diagnosis

The diagnosis of pancreatic trauma is challenging, frequently due to the “subtle” initial presentation. Frequently these injuries present later, and have a dormant period followed by a severe course of systemic

FIG. 3. Relationship of the pancreas to surrounding anatomic structures. (A) Note the proximity of the pancreatic head and the gallbladder, the right kidney/adrenal, the inferior vena cava, and the duodenum. Note the proximity of the pancreatic tail, the spleen, and the left kidney/adrenal. (B) Cross-sectional anatomy of the pancreatic duct—note the accessory (Santorini) and the major (Wirsung) pancreatic ducts and the fact that in about 5 per cent of patients these ducts are not fused. (C) Relationship between the pancreas, its blood supply, and other vascular structures in anatomic proximity. Note the rich vasculature surrounding the pancreas—a significant proportion of pancreatic injuries are associated with severe vascular injury. Please also note the transverse pancreatic artery—one hypothesis states that in minority of cases this vessel provides significant blood supply to the distal pancreas, which may result in distal pancreatic necrosis if transected.52

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inflammatory response presumed to be of some other etiology than trauma.4, 12 This is especially true with blunt pancreatic injuries. In general, injury to the duodenum and pancreas must be considered in all patients who sustain injury to the upper abdomen. Patients with blunt pancreatic injury may present with initially minimal physical findings and very subtle radiographic abnormalities. When facing blunt pancreatic injury, the most important determinant for accurate diagnosis is an experienced practitioner with a very high index of suspicion. The correlation of the mechanism of injury, the recognition of subtle signs and symptoms, and an understanding of the anatomy are crucial in early and accurate diagnosis of pancreatic trauma. In penetrating injury with suspected pancreatic involvement, one must determine the projectile trajectory, which will identify the anatomic injury.13 Four out of five penetrating injuries are due to gunshot wounds, and any trajectory that crosses the transduodenal-pancreatic line in any plane should raise suspicion. A useful anatomic landmark is any trajectory that crosses the first through third lumbar levels. Commonly the diagnosis of nonpancreatic injuries drives the decision to operate, but occasionally the bullet or knife trajectory alone near the pancreas warrants exploration. Diagnostic Studies Laboratory

Elevations in serum amylase and lipase are not reliable to determine pancreatic injury. In many cases

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they are normal even with high-grade injury. In one large series of operative pancreatic trauma, preoperative amylase was normal in 29 per cent of blunt trauma cases and only 77 per cent of penetrating trauma cases.3 Of interest, the same series reports that there was no amylase elevation in 28 per cent of cases of complete pancreatic trisection.3 Persistent elevations or rising levels mandate evaluation of the pancreas, duodenum, and small bowel. Imaging

Blunt injury evaluation starts with a detailed history and physical examination. Mechanism alone is considered a strong indication for computed tomography (CT) with fine-cut images through the pancreas and/or exploratory laparotomy. Double contrast (oral and intravenous) spiral computed tomography is routinely obtained unless the patient has peritoneal signs or other indications for abdominal exploration, and is the most frequent initial study for suspected pancreatic trauma.5 With good radiographic contrast enhancement, the pancreas can be adequately visualized, and peripancreatic hematoma or fluid, or parenchymal disruptions identified. The findings on CT, which may indicate pancreatic injury include: 1) peripancreatic fluid in the lesser sac; 2) pancreatic hematoma or partial laceration; 3) diffuse gland enlargement with pancreatitis or focal edema at the site of injury; and 4) thickening of the left anterior renal fascia (Fig. 4). These findings are often subtle. An additional finding which is easy to recognize is the presence of fluid interdigitating between the pancreas and the splenic

FIG. 4. Example of computed tomographic (top images) and magnetic resonance imaging (bottom images) of a midbody blunt pancreatic transection. Note the presence of associated splenic and left renal injuries.

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vein. It is important to remember that CT images showing laceration of the pancreatic body greater than 50 per cent significantly increase the likelihood of main pancreatic duct injury.14 If suspicion of major pancreatic ductal injury is present, endoscopic retrograde cholangiopancreatography (ERCP) or magnetic resonance cholangiopancreatography (MRCP) can be considered, but exploratory laparotomy and direct visualization of the pancreas remains the key diagnostic and therapeutic procedure in questionable cases.12 On occasion, ERCP is necessary to diagnose pancreatic ductal disruption but these tend to be cases that present late or in a delayed manner. Rarely, in severe blunt multiply injured patients, we have used MRCP or ERCP to examine the pancreatic duct in patients with a CT scan suspicious for transected or contused pancreas who do not otherwise require laparotomy, or whose other injuries are more critical (e.g., severe head injury, severe pelvic fractures, etc). Isolated rupture of the duodenum is uncommon and can be missed on CT, especially if the rupture occurs into the retroperitoneum. Though air and contrast leakage into the peritoneal cavity or retroperitoneum may be seen, the CT scan will most often demonstrate periduodenal, peripancreatic fluid or hematoma with subsequent surgical exploration and the diagnosis of a ruptured duodenum. Again, in our hands, these difficult diagnostic cases are best dealt with by a laparotomy. Magnetic Resonance Cholangiopancreatography

MRCP has emerged as an adjunctive test in diagnosis and management of pancreatic injury with suspected pancreatic ductal involvement.12 At our institution, MRCP is used selectively, in stable patients who do not otherwise warrant operative exploration. Negative MRCP obviates the need for further intervention, indeterminate or ‘weakly’ positive MRCP (suggestive of minor ductal injury) warrants further clinical observation, and a positive MRCP prompts either endoscopic (ERCP) or operative intervention.15 Ultrasonography

The role of ultrasonography in the setting of pancreatic injury is still being defined. Although traditional ultrasonography continues to have a very limited role in diagnosis of pancreatic injuries, there is some evidence that intravenous contrast-enhanced ultrasonography may be more useful in this setting.16, 17 One study demonstrated that expert ultrasonographers attained sensitivity of 44 per cent for pancreatic injuries, and were able to identify up to 80 per cent pancreatic ductal injuries using ultrasound techniques.18 Endoscopic ultrasound has been helpful in the man-

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agement of posttraumatic pancreatic complications, especially pancreatic pseudocysts.19 Diagnostics: Summary

Serum amylase and lipase are marginally helpful and can be normal with major pancreatic disruption. Computed tomography is the initial study of choice in the setting of suspected pancreatic injury. If warranted by high degree of clinical suspicion, MRCP and/or ERCP can be used to better define the extent of parenchymal and ductal injury in patients who do not require laparotomy for other reasons. The role of ultrasonography is still being defined in the setting of pancreatic injury, and this modality may be most useful as a monitoring tool for complications of pancreatic injury (i.e., pseudocysts). In our experience, in cases of blunt high energy transfer to the upper abdomen and the clinical picture of third-space fluid accumulation, malaise, abdominal or back pain (even without laboratory or radiographic evidence), the patient is best served with operative exploration to rule out pancreatic or small bowel injury. Therefore, in perplexing or difficult cases, the ultimate diagnostic study is exploratory laparotomy and complete visualization of all structures in the central retroperitoneum. Treatment

The general therapeutic approach to pancreatic trauma is based on the anatomy of the injury. The higher the injury grade the more complex the procedure(s) to treat the injury. In this approach, one divides the pancreas into left and right portions at the location of the superior mesenteric artery and portal vein. On the right side, the duodenum and pancreas are “inseparable” and in severe injury have to be treated as a unit. To the left of these vessels, the pancreas and the duodenum can be treated separately if needed and individual repair and resection performed. Concurrently, one has to divide the duodenum into “low” and “high” portions. The first two, or “low” portions (first and second) of the duodenum have complex anatomic structures within them (common bile duct and the sphincter of Oddi) and the pylorus. These require distinct maneuvers to diagnose injury (cholangiogram, direct visual inspection–operative versus endoscopic) and complex techniques to repair them. The first and second portions are densely adherent to the head of the pancreas, and the management of injury is complex. When dealing with these severe or “nonreconstructable” injuries with disruption of the ampullary-biliary-pancreatic union or major devitalizing injuries of the pancreatic head and duodenum, pancreatoduodenectomy may be the only surgical option.20

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The third and fourth portion, or the “high” duodenum, can generally be treated much like small bowel. Here, the diagnosis and management of injury is relatively simple, including debridement, closure, resection and reanastomosis, with or without drainage. In general, the prognosis associated with pancreaticduodenal injuries is influenced by the concomitant injuries, amount of blood loss, duration of shock, speed of resuscitation, and quality and nature of surgical intervention.20 Any and all repairs require extensive suction drainage as a mainstay to the operative control of these injuries. Treatment: Pancreatic Injury

Surgical techniques used to treat pancreatic or pancreaticoduodenal injury are many and varied. They include simple drainage, debridement and drainage, distal pancreatectomy with or without splenic salvage, near total pancreatectomy, creation of a roux loop to drain the injury, and pancreaticoduodenectomy (Whipple procedure–including the traditional, the pyloric sparing, and the total pancreatectomy variants).21–31 Only about 20 per cent of patients with pancreatic injuries require surgical resection of some sort, whether distal pancreatectomy or Whipple procedure. 24 The most common procedures include simple drainage, pancreatic debridement and drainage, and distal pancreatectomy (with or without splenic salvage). Pancreaticoduodenectomy is rarely performed. Early enteral feeding via jejunostomy or nasoenteric tube is very important in more complicated cases.24 Figure 5 demonstrates some of the operative strategies used in the setting of pancreatic trauma.

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Other techniques include glue sealants (fibrin glue, etc.), which have been described and found helpful to seal the parenchyma of the pancreas after tangential gunshot wounds or on resected surfaces.21, 22 Alternatives to surgery include nonoperative observation and endoscopic retrograde pancreatocholangiography with or without ductal stenting.23 Patients suspected of significant pancreatic injury should undergo a laparotomy. Intraoperative indicators of major ductal injury include direct visualization of the injury, complete transection of the pancreas, transverse laceration over 50 per cent of the gland, central perforation, and severely macerated pancreatic tissue.4 If the pancreatic injury is to the left of the mesenteric vessels and there is a suspicion of pancreatic duct injury, a distal pancreatectomy with or without splenic salvage and extensive drainage should be performed. If suspicion of major ductal injury is low (i.e., injury involves less than 50% width penetration of the superior or inferior border of the body or tail of the pancreas), then simple drainage alone is sufficient.20 In fact, in one large series nearly 50 per cent of patients were treated by pancreatic drainage alone.24 More information on pancreatic injury grading can be found in Table 1 and Fig. 6. A literature summary of overall operative procedure utilization in the setting of blunt and penetrating trauma can be found in Fig. 7 and Fig. 8, respectively. Pancreatic injury in the setting of open abdomen and damage control laparotomy presents difficult problems, with no clearly defined guidelines for injury management and significant controversy.10, 25, 26 A re-

FIG. 5. Commonly used surgical techniques in the setting of pancreatic trauma. (A) Simple drainage—sufficient in a significant number of cases. (B) Distal pancreatectomy with splenectomy and wide drainage. (C) Distal pancreatectomy with splenic preservation and wide drainage. (D) Whipple procedure with wide surgical drainage.

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TABLE 1. Pancreas Injury Scale Grade* I II III IV V

Hematoma Laceration Hematoma Laceration Laceration Laceration Laceration

Injury Description

AIS-90

Minor contusion without duct injury Superficial laceration without duct injury Major contusion without duct injury or tissue loss Major laceration without duct injury or tissue loss Distal transection or parenchymal injury with duct injury Proximal transection or parenchymal injury involving ampulla Massive disruption of pancreatic head

2 2 2 3 3 4 5

* Advance one grade for multiple injuries up to grade III. Proximal pancreas is to the patient’s right of the superior mesenteric vein. AIS, abbreviated injury scale.

FIG. 6. Schematic representation of pancreatic injury grading. Grade I injuries include minor contusions without ductal injury or superficial lacerations without ductal injury. Grade II injuries include major contusions or lacerations without ductal injury. Grade III injuries include distal pancreatic transections and parenchymal injuries with ductal injury. Grade IV injuries include proximal transections and major parenchymal injuries with ductal injuries. Grade V injuries feature massive disruptions of the pancreatic head with ampullary injury.

cent study at our institution indicated that pancreatic resection in the setting of damage control is associated with higher incidence of pancreatic complications (35% vs 17.9%), higher pancreatic injury grade (3.1 vs 2.3), but no difference in hospital mortality (43%) when compared with the patient group without pancreatic resection.27 Duodenal Injury

Much like with pancreatic injuries, there are numerous surgical techniques used for repair of the duodenum.28–30 Surgical options when approaching the duodenal injury include simple closure of the injury, external drainage, closure with tube duodenostomy, closure with antegrade drainage through the pylorus (nasogastric tube or long gastrostomy tube into the distal duodenum plus external suction drains), and retrograde drainage (through the jejunum). Another surgical approach includes closure with “triple tubes” and external drainage (gastrostomy, retrograde and feeding

J tubes plus external suction drains). Other options for duodenal disruption include jejunal patch (serosal or mucosal), pedicle grafts with jejunum or ileum, and duodenal resection and reanastomosis (including duodenoduodenostomy and duodenojejunostomy). Duodenal diverticulization, pyloric exclusion with gastrojejunostomy (using staples or suture), and pancreaticoduodenectomy (Whipple procedure) are reserved for the most severe duodenal injury involving the first and second portions.28–31 In our experience, the most commonly used options are closure with external drainage, closure with tube duodenostomy (most commonly including the retrograde drainage through the jejunum), duodenal resection and anastomosis for injury in third and fourth portions, and pyloric exclusion with gastrojejunostomy for first and second portions (either stapled or sutured). Others report nearly 20 per cent of patients being treated with duodenal diversion,24 and a significant percentage of patients being treated with either

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FIG. 7. Procedure utilization in the setting of blunt pancreatic injury, based on data collected from major blunt pancreatic trauma series.3, 6, 14, 53–55 Please note, other category includes pancreatorrhaphy and pancreatic duct stenting.

FIG. 8. Procedure utilization in the setting of penetrating pancreatic injury, based on data collected from major penetrating pancreatic trauma series.10, 53

simple closure or pyloric exclusion.29, 31 Regardless of the type of repair undertaken, wide surgical drainage using multiple drains is essential to successful management of severe pancreatic-duodenal injuries. Selection of one or more of the above operative procedures is determined by the grade (Table 2) and type of injury. Usually the higher the injury grade, the

more complex the surgical procedure. In general, most injuries are relatively simple to handle. Only rarely will pancreatic resection be required and pancreaticoduodenectomy is reserved for those patients with complex and severe destruction on the first and second portions of the duodenum and pancreatic head or those bleeding massively from the head of the pancreas.

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TABLE 2. Duodenum Injury Scale Grade* I

III

Hematoma Laceration Hematoma Laceration Laceration

IV

Laceration

V

Laceration Vascular

II

Injury Description

AIS-90

Involving single portion of duodenum Partial thickness, no perforation Involving more than one portion Disruption < 50% of circumference Disruption 50–75% circumference of D2 Disruption of 50–100% circumference of D1, D3, D4 Disruption > 75% circumference of D2 Involving ampulla or distal common bile duct Massive disruption of duodenopancreatic complex Devascularization of duodenum

2 3 2 4 4 4 5 5 5 5

D1, first portion of duodenum; D2, second portion of duodenum; D3, third portion of duodenum; D4, fourth portion of duodenum; AIS, abbreviated injury scale. * Advance one grade for multiple injuries up to grade III.

Delayed Repair or Damage Control

Because the majority of patients with a major injury to the pancreas or duodenum have an associated vascular injury and other abdominal visceral injuries, they will require emergency laparotomy and control of bleeding and contamination. Damage control surgical techniques have been used in all types of pancreatic and duodenal injuries. Even the most complex pancreaticoduodenal injury can be temporarily controlled with packing and a subsequent Whipple procedure performed.25, 32 Key in this maneuver is controlling contamination by resecting the injured duodenum and pancreatic head, with stapling across the distal pancreas and remaining stomach, and adequate drainage of the common bile duct and gastric remnant decompression with a nasogastric tube. This is done for 24 to 48 hours only to gain physiologic stability or to facilitate transfer of the patient to a higher level of trauma care. Occasionally the patient requiring Whipple procedure is too unstable to tolerate the resection and must undergo abdominal packing as a temporizing measure. Early return for pancreaticoduodenal resection is recommended in that setting. Of note, pancreatic involvement in the setting of open abdomen or damage control may be associated with greater morbidity and mortality when compared with cases without pancreatic involvement.32 Nonoperative Management of Pancreatic Injury

Although nonoperative management of other solid organs (spleen, liver) in the adult is an accepted practice, nonoperative management of pancreatic injuries is more controversial. Disruption of the pancreatic duct is the principal determinant in the management of pancreatic injuries. Because prompt surgical intervention is usually undertaken in patients with penetrating injuries or multiple organ involvement, delay in the diagnosis of a pancreatic duct injury most commonly occurs in patients with blunt abdominal trauma.

There is greater frequency of pancreatic-specific complications in patients requiring delayed surgical intervention. The reasons for the delay have been discussed and include the lack of signs or symptoms and an underestimation of the severity of pancreatic injury on the initial CT.33, 34 In the adult, most high-grade injuries are associated with other significant solid visceral injuries and a significant incidence of hollow visceral injury.35 In the adult patient population, the nonoperative approach to pancreatic injury can be used. This must be applied strictly and under a defined set of clinical conditions. The patient must be hemodynamically stable, have no peritoneal signs and have no other indications for operative exploration. They should undergo a high quality multi slice CT scan with intravenous and oral contrast enhancement. The presence of an incomplete or a complete pancreatic fracture is almost always associated with a concomitant main duct transaction and should be explored operatively or rapidly confirmed with ERCP or MRCP. The difficulties involved in initial CT scan grading of pancreatic injury highlight the need for great caution. False negative results or underestimation of pancreatic injury is associated with nonopacified bowel loops adjacent to the pancreas, motion and streak artifacts, as well as suboptimal contrast enhancement.36–40 With low-grade injury (grades I-III) where the separation of the fractured pancreatic fragments is minimal, ductal injury is not easily detected. Furthermore, overestimation on CT occurs in intermediate-grade injuries because deep lacerations, though the proximal pancreas are sometimes not associated with disruption of the proximal main duct.36–40 However, in any of these cases, we use ERCP or MRCP immediately to delineate the integrity of the main pancreatic duct. Certain complications of nonoperative management of pancreatic injuries may require subsequent invasive treatment. These include pancreatic pseudocyst, pan-

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creatic fistulae, and pancreatic ascites. Although most of these can be treated with percutaneous techniques, some require operative intervention and an internal drainage procedure, and a few are amenable to endoscopic drainage. Pediatric Injuries

Pediatric pancreatic injury can almost be characterized as a separate clinical entity. Nonoperative management is much more likely to be successful in this patient group. More isolated pancreatic injuries are seen with lower energy mechanisms and even grade III and some grade IV injuries have been managed without initial laparotomy.23, 35 Surgical intervention is reserved for devastating injuries of the pancreaticduodenal confluence and failures of nonoperative or endoscopic (ERCP) management.36 Conduct of the Laparotomy for Pancreaticoduodenal Injury

Every trauma laparotomy should be conducted in a standard fashion, starting with a general midline incision from xiphoid to symphysis pubis. Retraction is then applied to all four quadrants to help remove blood and/or other contamination, to visually inspect and identify all bleeding sites and hematomas, and to pack and control bleeding as necessary. Once active bleeding is controlled, one must then identify all major vascular injuries and control, ligate, and/or shunt as appropriate. This is followed by identification and control of all sources of contamination. An extensive Kocher maneuver then follows, with appropriate mobilization of the right colon and the hepatic flexure to examine the first and second portions of the duodenum and the head of the pancreas. The pancreatic body and tail and the third and fourth portions of the duodenum are examined by entering the lesser sac. An exploration of the lesser sac is performed by opening the omentum along the greater curvature away from the gastroepiploic vessels and lifting the stomach with large and long retractors to see all the body and tail of the pancreas. This maneuver will also nicely help expose the posterior stomach and lower thoracic and abdominal esophagus. If the distal pancreas is injured, the short gastric vessels are ligated to completely free the stomach from the spleen and allow full medial rotation of the stomach. The surgeon then must plan an approach to any retroperitoneal hematoma(s) and must determine the priority of all injury repairs, which may include vascular, gastrointestinal, pancreatic, renal/ureteral etc. At that time, one must also make the determination as to whether the patient can tolerate prolonged com-

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plex surgery based on the degree of hemodynamic instability, hypothermia, acidosis, fluid and blood requirements, and coagulopathy.32 If the patient has relative little physiologic derangement, one can proceed with definitive repair of all injuries. Not infrequently, a temporizing operation requires delayed management of the pancreatic injury. If the patient has had a major blood loss and significant pathophysiologic changes (i.e., coagulopathy, hypotension, hypothermia, etc), then an abbreviated set of operative maneuvers and damage control strategies can be called upon, as discussed in previous sections.25 Pancreatic-duodenal injuries are difficult to manage and often require complex surgical interventions, advanced surgical decision-making, and prolonged intensive care unit care. Last, the surgeon should decide if they have the experience and logistical support for complex pancreatic-duodenal resection and reconstruction. For surgeons and/or hospitals not able to care for such complex surgical scenario(s), surgical control of bleeding, contamination, temporizing resection, packing, and subsequent transfer to a Level I trauma center may represent the best choice. Description of operative strategies commonly used in the setting of pancreatic trauma can be found in Fig. 5. Special Issues in Operative Management of Pancreatic Trauma

The choice of operative approach and technique has been discussed in previous sections, but certain special clinical situations and adjunctive treatments need further explanation. These adjuncts include tissue sealants, drainage, feeding access, and techniques of pancreatic ductal anastomosis. Tissue sealants should be considered when dealing with pancreatic trauma. Tissue sealants (fibrin glue, etc) have been well-described and found to be helpful in sealing the parenchyma of the pancreas after tangential gunshot wounds or on resected surfaces.21, 22 Wide and ample drainage is crucial when treating pancreatic injuries operatively. Each injury should be drained with at least two drains—one anterior and one posterior to the pancreatic injury or resection site. For more extensive injuries involving the duodenum, additional drains placed in proximity to any repair or anastomosis are essential. Placement of feeding jejunostomy tube may be an important consideration for patients with pancreaticduodenal injuries because it provides a reliable method of postpyloric enteral access and the opportunity for early resumption of enteral nutrition. In some cases, nasojejunal tube placement at the time of the operation may be sufficient for provision of early postpyloric enteral nutrition. For patients who do not tolerate en-

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teral nutrition postoperatively, parenteral nutrition should be considered at the fifth to seventh postoperative day landmark. In terms of pancreaticojejunostomy creation, there are several different approaches.41–43 These include the single-layered, parachuted intussuscepted pancreaticojejunostomy43; binding technique wherein three centimeters of the serosal-muscular sheath of the jejunum is bound to the pancreatic remnant42; and the duct-to-mucosa technique.41 Pancreatic texture is an important determinant of ultimate anastomotic success, and it can be challenging to uniformly place pancreatic sutures in nonfibrotic pancreas.41, 43, 44 Complications

There are numerous potential complications associated with pancreatic trauma. In fact, one could argue that complications of pancreatic injury are just as injurious to the patient as the initial traumatic insult. The overall morbidity is 12 to 34 per cent but can reach as high as 60 per cent if diagnosis and/or treatment are delayed.12, 24 Although the reported frequencies vary, the most common complications associated with pancreatic injury and its treatment include abscess, pseudocyst, pancreatitis, fistula formation, and diabetes.45, 46 The emergence of systemic inflammatory response syndrome after pancreatic injury usually occurs 72 to 96 hours after the initial injury.47 Abscesses are fairly common after pancreatic injury, with reported frequency between 6 and 32 per cent.12, 45 Although many are treated with interventional radiologic techniques, some require operative management when inaccessible to interventional radiologic techniques. Traumatic pancreatic pseudocyst formation occurs between 5 and 30 per cent of cases and most require prolonged nonoperative management, nutritional support, and subsequent interval drainage (operative, interventional, or endoscopic).12, 45, 46 Pancreatitis, of various severity, has been noted in 10 to 15 per cent of cases.12, 45 Pancreatic fistulae have been reported to develop in approximately 10 per cent and can frequently be managed nonoperatively.10 ERCP-guided placement of endoprosthetic stents through the Sphincter of Oddi has been reported to help facilitate pancreatic fistula closure.10, 48 Delayed pancreatic hemorrhage due to blood vessel erosion from an infection or a pseudocyst occurs in fewer than 10 per cent of patients.10 Diabetes is a rare complication even with very extensive resection. In terms of the complications of duodenal injuries, significant mortality is not uncommon, and has been cited between 7 and 19 per cent overall.30 Leak rates have been reported to be as high as 43 per cent with

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primary duodenal repair, and reduced to 12 per cent with the introduction of pyloric exclusion for severe duodenal trauma.29 Fistula has been reported in approximately 5 per cent of severe duodenal injuries.49, 50 Determinants of Outcome

In pancreatic trauma, three-fourths of all fatalities occur in the first 48 to 72 hours postinjury.12, 44 The most common cause of death is hemorrhagic shock (early mortality) or persistent infection and late hemorrhage (late mortality).50, 51 In general, prognosis of pancreatic injury is influenced by the cause and complexity of the pancreatic injury, the associated injuries (extra and intra-abdominal), the amount of blood loss, duration of shock, as well as the nature of surgical intervention.20 Additional determinants of poor outcome in the presence of severe associated duodenal injury include abdominal trauma index greater than 40, duodenal injury score >12, and the presence of injury to the head of the pancreas.31 Conclusions

Pancreatic and pancreatic-duodenal injuries continue to pose a difficult diagnostic and therapeutic challenge to physicians. Although multiple diagnostic and treatment options are available, few of them are consistently reliable. Correlation of the mechanism of injury and a high index of suspicion are key to early diagnosis and initiation of appropriate therapy. Recent advances in endoscopic techniques and imaging have improved diagnosis and decreased the need for diagnostic laparotomy but surgical exploration is still necessary for some cases and for severe injury management. Grade of injury, physiologic insult, and familiarity with complex pancreatic repair and reconstruction are key determinants of outcome. REFERENCES

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