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Pancreatic Trauma
CHAPTER
102
Pancreatic Trauma Syed Nabeel Zafar
|
Edward E. Cornwell III
P
ancreatic injuries, despite their relative infrequency, are regarded with great respect among experienced trauma surgeons because of their significant associated mortality and morbidity. Pancreatic injuries occur in up to 3% of patients with significant blunt abdominal trauma and a slightly higher percentage of those sustaining abdominal gunshot and stab wounds.1 Penetrating trauma accounts for more than 70% of pancreatic injuries, and, given its anatomic location, associated injuries are the rule. The mortality rate for pancreatic injuries ranges from 10% to 25%, with the majority of deaths occurring in the first 48 hours from massive bleeding and its complications. The systemic inflammatory response syndrome, sepsis, and multisystem organ failure account for the vast majority of delayed deaths. Among patients with pancreatic injury surviving the initial hemorrhage, nearly half will have a complication of their pancreatic wound, such as abscess, fistula, pseudocyst, false aneurysm, or anastomotic leak.2,3 Patients with penetrating trauma to the pancreas experience injuries with equal frequency along the head, body, and tail of the organ. In victims of blunt trauma, the deceleration and direct compression mechanism of injury explain why the neck of the pancreas in the prevertebral segment of the gland is the most commonly injured region. The surgical management of pancreatic injury is complicated by the gland’s complex anatomic relationship with the duodenum, biliary tract, splanchnic vessels, liver, spleen, vena cava, and aorta. Operative decisions are challenging because of the unforgiving nature of the gland, relative unfamiliarity with the techniques, controversy regarding the technical details, and the judgment required to decide on the extent of surgery. The overall management is challenging, given its often delayed clinical presentation and lack of specific diagnostic modalities. The use of computed tomographic (CT) scans and endoscopic retrograde cholangiopancreatography (ERCP) has fostered the nonoperative management of pancreatic trauma, yet there remains a role for definitive operative therapy in the setting of hemorrhage and main pancreatic duct disruption. This chapter will outline the clinical presentation of pancreatic injuries, address critical points regarding technical surgical approaches, and review the common complications related to these difficult injuries.
DIAGNOSIS Patients with torso trauma who manifest early indications of intraabdominal bleeding or peritonitis require immediate operative intervention, at which time direct evaluation of the pancreas should be carried out. For patients who
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are hemodynamically stable, a thorough diagnostic evaluation is warranted. The stable patient with blunt abdominal trauma is the person in whom timely diagnosis of pancreatic injury is most challenging. Physical examination and evaluation of hemodynamic status remain the key factors in the diagnostic algorithm of abdominal trauma. A hypotensive patient with abdominal trauma should proceed to the operating room without delay. For the clinically stable patient, selective management can be successful as long as careful attention is given to clinical progress or deterioration. Even patients with abdominal gunshot wounds, once uniformly accepted as a clear indication for exploratory laparotomy, are now managed selectively at some large trauma centers under the appropriate circumstances. The initial clinical examination (vital signs, physical examination of the abdomen) becomes the main determinant of whether the patient is triaged immediately to the operating room, to other diagnostic testing, or to an observation site where physical examinations and monitoring can be undertaken. Important prerequisites for considering selective management of abdominal gunshot wounds rather than mandatory exploration include (1) experienced in-house surgeons who are available to take the patient to the operating room in the event of change of the initial benign clinical examination; (2) a predetermined site in the hospital that facilitates observation and serial examination (i.e., monitoring the vital signs, urine output, hematocrit, and repeated abdominal examinations); and (3) priority status that allows patients with deteriorating clinical examinations to be triaged immediately to the operating room. Serial physical examination is more universally accepted as a mainstay in the selective management of stab wounds to the anterior abdomen. A full laboratory panel should be collected including serum amylase and lipase levels. Serum amylase is elevated in 80% of patients with blunt pancreatic injury. This figure is much lower for penetrating wounds, but in either case an elevated amylase level mandates a directed evaluation of the pancreas. Studies show that amylase levels upon admission are not very sensitive. The diagnostic yield of amylase is time sensitive, and a value obtained 3 to 6 hours after presentation has a much higher accuracy in predicting pancreatic trauma.4,5 An elevated amylase level can be a result of bowel perforation, salivary gland trauma, or nondisruptive pancreatic injury because it is not a very specific test. Serum lipase may be used if there is confusion because it is not elevated when hyperamylasemia is of salivary origin. Pancreatic isoenzyme fractionation can identify salivary amylase but is often not available. It is often useful to repeat the serum amylase in patients being observed for abdominal trauma because first blood
Pancreatic Trauma CHAPTER 102 1208.e1
ABSTRACT Pancreatic trauma continues to carry a significant risk of mortality and morbidity. Therefore treating other injuries to stabilize the patient may be necessary before definitive operative management of the pancreatic injury can occur. Prompt diagnosis, appropriate resuscitation, and careful surgical technique are paramount in the proper treatment of pancreatic trauma. The grade of the injury, and particularly the presence and location of a pancreatic ductal injury, determines the most appropriate operation (hemostasis, débridement, drainage versus resection, pyloric exclusion, or rarely pancreaticoduodenectomy). Finally, complications are likely to occur, so close observation and early interventions are essential to the recovery of patients with pancreatic trauma.
KEYWORDS Pancreatic trauma, pancreaticoduodenal trauma, injury, abdominal injury, trauma Whipple, nonoperative management
Pancreatic Trauma CHAPTER 102
specimens may be drawn so close to the time of wounding that a misleading normal value may result. Additional diagnostic studies are indicated if there is suspicion of pancreatic injury. An example should be patients with amylase elevation and upper abdominal tenderness and distention. Plain or contrast radiographs offer little assistance. The focused abdominal sonogram for trauma (FAST) rapidly identifies fluid in the hepatorenal recess of Morrison. As a modality that provides prompt assessment of patients with blunt trauma in the emergency department, it has essentially supplanted the diagnostic peritoneal lavage. Following the initial physical examination, the hemodynamically stable patient should undergo a CT scan of the abdomen and pelvis (with intravenous contrast) to elucidate the presence of any visceral injuries. A pancreatic injury can be challenging to assess, given that some injuries may not be obvious without significant inflammatory changes. Such findings may not be apparent in the initial 24 hours post injury. In 2009 the American Association for the Surgery of Trauma (AAST) published a multicenter study examining the use of CT scan in the evaluation of pancreatic injuries. They enrolled 206 patients with confirmed pancreatic injuries on operative exploration and determined the following radiographic characteristics were “hard signs” of a pancreatic injury: • Active bleeding • Pancreatic hematoma or laceration • Diffuse enlargement or edema of pancreas • Low pancreatic attenuation The study also suggested that lacerations greater than 50% of the gland thickness on CT scan should raise concern for a pancreatic ductal injury.6 In cases in which the clinical findings leading to the CT scan are persistent and the CT scan is equivocal or even negative, ERCP will delineate the pancreatic ductal anatomy (Fig. 102.1). Magnetic resonance cholangiopancreatography (MRCP) has not been evaluated specifically in large numbers of trauma patients, but its use has been extrapolated from its use in nontraumatic scenarios. Its potential benefits include its noninvasive nature, and the fact it can be performed even after anatomy-altering surgery has made ERCP impossible (i.e., pyloric exclusion or gastric bypass procedures). However, it does have a potential drawback, specifically the need to send an acutely injured patient to a remote location. Although the situation occurs infrequently, ERCP can identify major ductal disruption well before clinical signs lead to laparotomy. Early identification and treatment of pancreatic injury can reduce morbidity.
NONOPERATIVE MANAGEMENT As stressed previously, to attempt nonoperative management for abdominal trauma, the patient must be hemodynamically stable in a facility where there is an experienced in-house surgeon and facilities available for intensive monitoring, serial examinations, and the option to be in the operating room at a moment’s notice in the event that the patient’s condition deteriorates. Nonoperative management of pancreatic trauma diagnosed on CT scanning is generally reserved for grade I and II injuries.7
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FIGURE 102.1 Endoscopic retrograde cholangiopancreatography performed after original damage control surgery for gunshot wound to abdomen and before reexploration. Arrow shows extravasation of contrast from pancreatic duct.
Velmahos et al. conducted a multiinstitutional review of blunt abdominal trauma and studied 230 patients with blunt pancreatoduodenal injury.8 Ninety-seven (42%) of these were selected for nonoperative management and with a success rate of 90%. A study from the Nationwide Inpatient Sample shows that over a 10-year period from 1998 to 2009 the number of pancreatoduodenal injuries increased by 8.3%; however, the proportion of patients receiving operative intervention declined from 21.7% to 19.8% without affecting morbidity.9 ERCP can be a very useful adjunct in the diagnosis and management of lowgrade pancreatic injuries.10
INTRAOPERATIVE EVALUATION After hemorrhage is controlled in the management of pancreatic trauma, delayed complications, such as pancreatic fistulae and pseudocysts, intraabdominal abscesses, and multisystem organ dysfunction, correlate in frequency with the severity of the pancreatic injury. Therefore the most extensive surgical procedures in the management of pancreatic trauma are reserved for patients with combined pancreaticoduodenal injuries. The overall goals of these surgical procedures are to (1) maintain pancreaticenteric and biliary-enteric flow, (2) provide wide drainage for all pancreatic and duodenal injuries and anastomoses, and (3) divert the gastrointestinal stream so as to minimize stimulation of the pancreaticobiliary secretions. In most patients with pancreatic injury, the diagnosis is confirmed intraoperatively. Evaluation of pancreatic trauma requires several surgical maneuvers. A Kocher maneuver entails incising the lateral peritoneal attachments
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SECTION III Pancreas, Biliary Tract, Liver, and Spleen
FIGURE 102.2 Any hematomas overlying the gland must be unroofed.
FIGURE 102.3 With the peritoneum along the inferior border of the pancreas divided, the surgeon’s finger is slipped behind the gland to evaluate for palpable parenchymal defects.
to the second and third portion of the duodenum and mobilizing the duodenum and the head of the pancreas to the patient’s left. This proceeds along the avascular plane to the superior mesenteric vein. A replaced right hepatic artery is occasionally encountered as a branch of the superior mesenteric artery (SMA), and care must be taken because it can be injured during the dissection. This facilitates inspection of the posterior aspect of the head of the gland, as well as the posterior wall of the duodenum, and provides a view of the suprarenal inferior vena cava. The anterior aspect of the entire gland may be evaluated by entering the lesser sac through the gastrocolic omentum. With a wide incision through the omentum and retraction of the stomach superiorly and the transverse colon inferiorly, a thorough evaluation of the gland becomes possible. Any hematomas overlying the gland must be evacuated and thoroughly explored because they frequently mask underlying severe pancreatic parenchymal or ductal injury (Fig. 102.2). A patient may occasionally present with severe injury to the posterior aspect of the pancreas, with the anterior capsule intact. This is seen most commonly in patients with blunt mechanisms of injury. When hematoma or contusion raises an index of suspicion for injuries that may involve the posterior aspect of the gland, an incision should be made in the peritoneum and areolar tissue along the inferior aspect of the pancreas. Most of these injuries will reside in the prevertebral region of the pancreas. After division of the peritoneum along the inferior border of the pancreas, the surgeon’s finger is slipped behind the gland to evaluate for parenchymal defects by palpation and direct visualization (Fig. 102.3). Full evaluation of the tail of the pancreas can be facilitated by the Aird maneuver.11 Originally described in 1955
FIGURE 102.4 Aird maneuver is used to mobilize the spleen and tail of the pancreas.
to facilitate adrenalectomy, this procedure entails division of the avascular splenic ligaments (i.e., splenorenal, splenocolic and splenophrenic) and mobilization of the spleen and the tail of the pancreas from the patient’s left to right (Fig. 102.4).
Pancreatic Trauma CHAPTER 102
OPERATIVE TREATMENT AAST pancreatic organ injury scale grades injuries from I through V (Table 102.1).12 The use of a combination of the injury grade, injury location, and other concomitant injuries (especially to the duodenum) helps to determine the surgical treatment for the pancreatic injury. Patients with lower-grade pancreatic injuries are significantly easier to manage. Observation and drainage along with débridement and meticulous hemostasis may be all that is necessary for grade I (minor contusion or superficial laceration) or grade II injuries (major contusion or laceration). Major disruption of the pancreatic tissue requires a decision regarding the likelihood of major ductal injury. Even in major trauma centers, the gold standard ERCP is not available intraoperatively in the middle of the night. Suspicion of ductal involvement is raised by the anatomic location of the injury and the amount of local pancreatic tissue disruption. Pancreatic juice can occasionally be seen leaking at the open ends of a duct. When major ductal injury is suspected, it should, in most instances, prompt definitive therapy. Under some circumstances, such as cardiovascular instability, drainage alone should be performed, after which the patient almost always has a pancreatic fistula. The popular concept of a continuum of resuscitative care in the operating room/surgical intensive care unit, the acceptance of distal pancreatectomy for wounds to the left of the SMA, and the availability of postoperative ERCP in patients with more severe injuries who have been adequately drained, all render intraoperative pancreatography rarely indicated. In the rare instance when the duodenum is open already from the traumatic injury, then it is reasonable to perform fluoroscopic pancreatography by cannulating the ampulla to inject contrast. If there is no associated duodenal wound, the duodenum should not be opened
TABLE 102.1 American Association for the Surgery of Trauma Organ Injury Scaling: Pancreas Type of Injury
GRADE I
Hematoma Laceration
Minor contusion without duct injury Superficial laceration without duct injury
GRADE II Hematoma Laceration
Major contusion without duct injury or tissue loss Major laceration without duct injury or tissue loss
GRADE III Hematoma
Distal transection or parenchymal injury with duct injury
GRADE IV Laceration
Proximal transection or parenchymal injury involving ampulla
GRADE V Laceration
Massive disruption of pancreatic head
From Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling, II: pancreas, duodenum, small bowel, colon, and rectum. J Trauma. 1990;30(11):1427–1429.
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for the sole reason of performing a pancreatogram. Another technique for performing a pancreatogram is a cystic duct cholangiogram by passing the catheter into the common bile duct and refluxing contrast into the main pancreatic duct. Such adjuncts as secretin or intravenous opiates may enhance the ability to perform a pancreatogram in this fashion. After the pancreatic injury has been identified, the location of the injury will determine the appropriate treatment. The pancreatic duct injury can be divided into proximal (at the head or neck, to the right side of the superior mesenteric vessels) and distal injuries (at the distal body and tail to the left side of the mesenteric vessels). Grade III pancreatic injury with a distal transection or parenchymal injury is most easily treated by distal pancreatectomy. In the case of active ongoing hemorrhage, the most expeditious way to perform this is in combination with a splenectomy. The spleen and pancreatic tail will have already been mobilized, leaving only the division of the pancreas itself, the short gastric arteries, splenic artery, and splenic vein. As with all other operations on the pancreas for trauma, the area should be widely drained with closed-suction drains to manage possible postoperative pancreatic leak. Many options (including staples, sutures, or electrocautery) are acceptable for transecting the pancreas and controlling the transected end of the gland; their use is based on surgeon preference. Ideally the transected pancreatic duct should be identified and closed directly, often with either U stitch or a figure-of-eight suture. Other options include omental patch or fibrin glue for helping control the distal pancreatic stump. The possibility of a distal pancreatectomy without splenectomy (spleenpreserving distal pancreatectomy) can be considered in certain patient populations based on clinical stability and isolated injuries. The small benefit of helping to prevent overriding postsplenectomy sepsis by leaving the spleen in is often outweighed by the significant time that it takes to perform this tedious operation (Fig. 102.5). An extended distal pancreatectomy can be performed if the laceration resides to the right of the superior mesenteric vessels and may be an option that potentially avoids a Whipple procedure. Another alternative is a central pancreatectomy, which can be considered in the setting of a proximal ductal transection with otherwise normal distal pancreatic parenchyma. The procedure involves resecting the central portion of the gland and débriding back to viable tissue to properly close the end of the proximal duct. The distal pancreatic remnant is then drained by creating a Roux-en-Y pancreaticojejunostomy. Again, wide drainage should be performed to control a postoperative fistula. Surgical management of severe injuries to the pancreaticoduodenal complex are some of the most complex that a trauma surgeon deals with. These grades IV and V injuries involve proximal ductal injury or massive destruction of the pancreatic head to the right of the superior mesenteric vein and are often in close association with the C-loop of the duodenum. The scope of procedure performed varies with the severity of the injury, reserving the most aggressive surgical treatments for the most severe of these combined pancreaticoduodenal injuries.
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SECTION III Pancreas, Biliary Tract, Liver, and Spleen
There are three main goals in any surgical procedure for severe pancreatic injury. The first is to maintain enteric flow from the pancreas to the biliary tree. The second is to divert any gastrointestinal secretions to minimize stimulation of the pancreatic exocrine function. The third is to widely drain in anticipation of postoperative leaks or fistulas. The main surgical dictum for treatment of the injuries should be to perform the minimal surgical intervention necessary to adequately treat the injury and accomplish these objectives. Significant injuries to the
FIGURE 102.5 Distal pancreatectomy with splenic preservation.
head and neck that do not injure the major pancreatic duct are most appropriately treated with simple débridement and drainage. This approach can be used in the hemodynamically unstable patient undergoing damage control surgery as a temporizing measure, allowing further investigation, such as ERCP or MRCP, after the initial operation. In the patient who is hemodynamically stable or at the second-stage operation after initial damage control, there are multiple options for dealing with injuries to the pancreaticoduodenal complex. If at the initial operation the pancreas is widely drained and the abdomen is closed, postoperative ERCP is performed to place a pancreatic stent (Fig. 102.6). This can give the main pancreatic duct injury time to heal without performing a major pancreatic resection. When pancreatic injuries are associated with major duodenal injuries, drainage or resection of pancreas can be combined with suturing or stapling of the pylorus (pyloric exclusion procedure) to divert gastric flow from the duodenum. Gastrointestinal continuity is then accomplished by gastrojejunostomy (Fig. 102.7). It is quite
FIGURE 102.6 The same patient as Fig. 102.1 following placement of a pancreatic stent.
FIGURE 102.7 The pyloric exclusion procedure.
Pancreatic Trauma CHAPTER 102
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concept that somatostatin may reduce the volume of output (and promote closure) after a pancreatic fistula has developed. Rarely, late management of the pancreatic fistula that shows no sign of closure after many weeks of nonoperative management or the patient who forms a pseudocyst after drain removal requires internal drainage via a Roux-en-Y jejunal limb. Postoperative pancreatic abscess usually demands open débridement and wide drainage. However, single uniloculated collections in the absence of much pancreatic necrosis (as determined by dynamic CT scanning) may respond to percutaneous CT-guided drainage with large catheters. Pulmonary and infectious complications also remain high at 20% and 13%, respectively, and need to be identified and managed appropriately.9 Literature shows that the risk factors for postoperative complications include age, injury location, injury grade, associated vascular injuries, and delay to surgery and are predictors of morbidity.9,15,16 FIGURE 102.8 The Whipple procedure mobilizing the head of the gland.
remarkable that gastroduodenal continuity is reestablished by 4 to 6 weeks after pyloric exclusion even when heavy nonabsorbable sutures or staples are used. The pyloric exclusion procedure has largely replaced the duodenal diverticulization procedure, which entails antrectomy and gastrojejunostomy, as well as drainage and decompression of the duodenal injury and drainage of the pancreatic injury. When pancreaticoduodenal trauma is so severe that hemorrhage control or extensive destruction of the tissue necessitates resection of the second portion of the duodenum or the head of the pancreas, a pancreaticoduodenectomy (Whipple procedure) is indicated. The avascular plane between the neck of the pancreas and the superior mesenteric vein allows for safe mobilization of the gland for resection (Fig. 102.8). A staged Whipple may be the safest option for the patient after hemorrhage and enteric contamination are controlled because peripancreatic packing and drainage are safe and effective temporary measures until the patient’s physiology is restored.13
POSTOPERATIVE CONSIDERATIONS When drainage is performed for major pancreatic injuries, the guideline for removing the drain is tolerance of regular tube feedings and the absence of high-volume or highamylase content in the drainage fluid. A feeding jejunostomy is an important adjunct to major pancreatic injuries requiring pancreatic resection, pyloric exclusion, or the Whipple procedure because accumulated evidence shows the importance of early enteric feeding in maintaining the immune function of the gut in critically injured patients. Up to one-third of patients with major pancreatic injuries develop a pancreatic fistula. Most of these resolve spontaneously with adequate drainage. The evidence of a beneficial effect of somatostatin following pancreatic resection for trauma fails to justify the expense associated with its routine use.14 There is more support for the
SUMMARY Pancreatic trauma continues to carry a significant risk of mortality and morbidity. Therefore treating other injuries to stabilize the patient may be necessary before definitive operative management of the pancreatic injury can occur. Prompt diagnosis, appropriate resuscitation, and careful surgical technique are paramount in the proper treatment of pancreatic trauma. The grade of the injury, and particularly the presence and location of a pancreatic ductal injury, determines the most appropriate operation (hemostasis, debridement, drainage versus resection, pyloric exclusion, or rarely pancreaticoduodenectomy). Finally, complications are likely to occur, so close observation and early interventions are essential to the recovery of patients with pancreatic trauma.
ACKNOWLEDGMENTS This chapter is an update from the prior chapters on pancreatic trauma by Edward E. Cornwell III, Elliot R. Haut, and David Kuwayama from the 6th edition of Shackelford’s Surgery of the Alimentary Tract and by Amy Rushing, Edward E. Cornwell III, and Elliott R. Haut from the 7th edition of Shackelford’s Surgery of the Alimentary Tract.
REFERENCES 1. Subramanian A, Dente CJ, Feliciano DV. The management of pancreatic trauma in the modern era. Surg Clin North Am. 2007;87(6): 1515-1532. 2. Ivatury R, Nallathambi M, Rao P, Stahl W. Penetrating pancreatic injuries. Analysis of 103 consecutive cases. Am Surg. 1990;56(2):90-95. 3. Young PR Jr, Meredith JW, Baker CC, Thomason MH. Pancreatic injuries resulting from penetrating trauma: a multi-institution review/ discussion. Am Surg. 1998;64(9):838. 4. Mahajan A, Kadavigere R, Sripathi S, Rodrigues GS, Rao VR, Koteshwar P. Utility of serum pancreatic enzyme levels in diagnosing blunt trauma to the pancreas: a prospective study with systematic review. Injury. 2014;45(9):1384-1393. 5. Takishima T, Sugimoto K, Hirata M, Asari Y, Ohwada T, Kakita A. Serum amylase level on admission in the diagnosis of blunt injury to the pancreas: its significance and limitations. Ann Surg. 1997;226(1):70-76. 6. Phelan HA, Velmahos GC, Jurkovich GJ, et al. An evaluation of multidetector computed tomography in detecting pancreatic injury:
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SECTION III Pancreas, Biliary Tract, Liver, and Spleen
results of a multicenter AAST study. J Trauma. 2009;66(3):641-646; discussion 646-647. 7. Bokhari F, Phelan H, Holevar M, et al. EAST Guidelines for the Diagnosis and Management of Pancreatic Trauma. Chicago: Eastern Association for the Surgery of Trauma (EAST); 2009. 8. Velmahos GC, Tabbara M, Gross R, et al. Blunt pancreatoduodenal injury: a multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT). Arch Surg. 2009;144(5):413419; discussion 419-420. 9. Ragulin-Coyne E, Witkowski ER, Chau Z, et al. National trends in pancreaticoduodenal trauma: interventions and outcomes. HPB (Oxford). 2014;16(3):275-281. 10. Rogers SJ, Cello JP, Schecter WP. Endoscopic retrograde cholangiopancreatography in patients with pancreatic trauma. J Trauma. 2010;68(3):538-544.
11. Aird I, Helman P. Bilateral anterior transabdominal adrenalectomy. Br Med J. 1955;2(4941):708-709. 12. Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling, II: pancreas, duodenum, small bowel, colon, and rectum. J Trauma. 1990;30(11):1427-1429. 13. Seamon MJ, Kim PK, Stawicki SP, et al. Pancreatic injury in damage control laparotomies: is pancreatic resection safe during the initial laparotomy? Injury. 2009;40(1):61-65. 14. Nwariaku FE, Terracina A, Mileski WJ, Minei JP, Carrico CJ. Is octreotide beneficial following pancreatic injury? Am J Surg. 1995; 170(6):582-585. 15. Recinos G, DuBose JJ, Teixeira PG, Inaba K, Demetriades D. Local complications following pancreatic trauma. Injury. 2009;40(5):516-520. 16. Lin BC, Chen RJ, Fang JF, Hsu YP, Kao YC, Kao JL. Management of blunt major pancreatic injury. J Trauma. 2004;56(4):774-778.
102
Pancreatic Trauma Syed Nabeel Zafar
|
Edward E. Cornwell III
P
ancreatic injuries, despite their relative infrequency, are regarded with great respect among experienced trauma surgeons because of their significant associated mortality and morbidity. Pancreatic injuries occur in up to 3% of patients with significant blunt abdominal trauma and a slightly higher percentage of those sustaining abdominal gunshot and stab wounds.1 Penetrating trauma accounts for more than 70% of pancreatic injuries, and, given its anatomic location, associated injuries are the rule. The mortality rate for pancreatic injuries ranges from 10% to 25%, with the majority of deaths occurring in the first 48 hours from massive bleeding and its complications. The systemic inflammatory response syndrome, sepsis, and multisystem organ failure account for the vast majority of delayed deaths. Among patients with pancreatic injury surviving the initial hemorrhage, nearly half will have a complication of their pancreatic wound, such as abscess, fistula, pseudocyst, false aneurysm, or anastomotic leak.2,3 Patients with penetrating trauma to the pancreas experience injuries with equal frequency along the head, body, and tail of the organ. In victims of blunt trauma, the deceleration and direct compression mechanism of injury explain why the neck of the pancreas in the prevertebral segment of the gland is the most commonly injured region. The surgical management of pancreatic injury is complicated by the gland’s complex anatomic relationship with the duodenum, biliary tract, splanchnic vessels, liver, spleen, vena cava, and aorta. Operative decisions are challenging because of the unforgiving nature of the gland, relative unfamiliarity with the techniques, controversy regarding the technical details, and the judgment required to decide on the extent of surgery. The overall management is challenging, given its often delayed clinical presentation and lack of specific diagnostic modalities. The use of computed tomographic (CT) scans and endoscopic retrograde cholangiopancreatography (ERCP) has fostered the nonoperative management of pancreatic trauma, yet there remains a role for definitive operative therapy in the setting of hemorrhage and main pancreatic duct disruption. This chapter will outline the clinical presentation of pancreatic injuries, address critical points regarding technical surgical approaches, and review the common complications related to these difficult injuries.
DIAGNOSIS Patients with torso trauma who manifest early indications of intraabdominal bleeding or peritonitis require immediate operative intervention, at which time direct evaluation of the pancreas should be carried out. For patients who
1208
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Adil A. Shah
are hemodynamically stable, a thorough diagnostic evaluation is warranted. The stable patient with blunt abdominal trauma is the person in whom timely diagnosis of pancreatic injury is most challenging. Physical examination and evaluation of hemodynamic status remain the key factors in the diagnostic algorithm of abdominal trauma. A hypotensive patient with abdominal trauma should proceed to the operating room without delay. For the clinically stable patient, selective management can be successful as long as careful attention is given to clinical progress or deterioration. Even patients with abdominal gunshot wounds, once uniformly accepted as a clear indication for exploratory laparotomy, are now managed selectively at some large trauma centers under the appropriate circumstances. The initial clinical examination (vital signs, physical examination of the abdomen) becomes the main determinant of whether the patient is triaged immediately to the operating room, to other diagnostic testing, or to an observation site where physical examinations and monitoring can be undertaken. Important prerequisites for considering selective management of abdominal gunshot wounds rather than mandatory exploration include (1) experienced in-house surgeons who are available to take the patient to the operating room in the event of change of the initial benign clinical examination; (2) a predetermined site in the hospital that facilitates observation and serial examination (i.e., monitoring the vital signs, urine output, hematocrit, and repeated abdominal examinations); and (3) priority status that allows patients with deteriorating clinical examinations to be triaged immediately to the operating room. Serial physical examination is more universally accepted as a mainstay in the selective management of stab wounds to the anterior abdomen. A full laboratory panel should be collected including serum amylase and lipase levels. Serum amylase is elevated in 80% of patients with blunt pancreatic injury. This figure is much lower for penetrating wounds, but in either case an elevated amylase level mandates a directed evaluation of the pancreas. Studies show that amylase levels upon admission are not very sensitive. The diagnostic yield of amylase is time sensitive, and a value obtained 3 to 6 hours after presentation has a much higher accuracy in predicting pancreatic trauma.4,5 An elevated amylase level can be a result of bowel perforation, salivary gland trauma, or nondisruptive pancreatic injury because it is not a very specific test. Serum lipase may be used if there is confusion because it is not elevated when hyperamylasemia is of salivary origin. Pancreatic isoenzyme fractionation can identify salivary amylase but is often not available. It is often useful to repeat the serum amylase in patients being observed for abdominal trauma because first blood
Pancreatic Trauma CHAPTER 102 1208.e1
ABSTRACT Pancreatic trauma continues to carry a significant risk of mortality and morbidity. Therefore treating other injuries to stabilize the patient may be necessary before definitive operative management of the pancreatic injury can occur. Prompt diagnosis, appropriate resuscitation, and careful surgical technique are paramount in the proper treatment of pancreatic trauma. The grade of the injury, and particularly the presence and location of a pancreatic ductal injury, determines the most appropriate operation (hemostasis, débridement, drainage versus resection, pyloric exclusion, or rarely pancreaticoduodenectomy). Finally, complications are likely to occur, so close observation and early interventions are essential to the recovery of patients with pancreatic trauma.
KEYWORDS Pancreatic trauma, pancreaticoduodenal trauma, injury, abdominal injury, trauma Whipple, nonoperative management
Pancreatic Trauma CHAPTER 102
specimens may be drawn so close to the time of wounding that a misleading normal value may result. Additional diagnostic studies are indicated if there is suspicion of pancreatic injury. An example should be patients with amylase elevation and upper abdominal tenderness and distention. Plain or contrast radiographs offer little assistance. The focused abdominal sonogram for trauma (FAST) rapidly identifies fluid in the hepatorenal recess of Morrison. As a modality that provides prompt assessment of patients with blunt trauma in the emergency department, it has essentially supplanted the diagnostic peritoneal lavage. Following the initial physical examination, the hemodynamically stable patient should undergo a CT scan of the abdomen and pelvis (with intravenous contrast) to elucidate the presence of any visceral injuries. A pancreatic injury can be challenging to assess, given that some injuries may not be obvious without significant inflammatory changes. Such findings may not be apparent in the initial 24 hours post injury. In 2009 the American Association for the Surgery of Trauma (AAST) published a multicenter study examining the use of CT scan in the evaluation of pancreatic injuries. They enrolled 206 patients with confirmed pancreatic injuries on operative exploration and determined the following radiographic characteristics were “hard signs” of a pancreatic injury: • Active bleeding • Pancreatic hematoma or laceration • Diffuse enlargement or edema of pancreas • Low pancreatic attenuation The study also suggested that lacerations greater than 50% of the gland thickness on CT scan should raise concern for a pancreatic ductal injury.6 In cases in which the clinical findings leading to the CT scan are persistent and the CT scan is equivocal or even negative, ERCP will delineate the pancreatic ductal anatomy (Fig. 102.1). Magnetic resonance cholangiopancreatography (MRCP) has not been evaluated specifically in large numbers of trauma patients, but its use has been extrapolated from its use in nontraumatic scenarios. Its potential benefits include its noninvasive nature, and the fact it can be performed even after anatomy-altering surgery has made ERCP impossible (i.e., pyloric exclusion or gastric bypass procedures). However, it does have a potential drawback, specifically the need to send an acutely injured patient to a remote location. Although the situation occurs infrequently, ERCP can identify major ductal disruption well before clinical signs lead to laparotomy. Early identification and treatment of pancreatic injury can reduce morbidity.
NONOPERATIVE MANAGEMENT As stressed previously, to attempt nonoperative management for abdominal trauma, the patient must be hemodynamically stable in a facility where there is an experienced in-house surgeon and facilities available for intensive monitoring, serial examinations, and the option to be in the operating room at a moment’s notice in the event that the patient’s condition deteriorates. Nonoperative management of pancreatic trauma diagnosed on CT scanning is generally reserved for grade I and II injuries.7
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FIGURE 102.1 Endoscopic retrograde cholangiopancreatography performed after original damage control surgery for gunshot wound to abdomen and before reexploration. Arrow shows extravasation of contrast from pancreatic duct.
Velmahos et al. conducted a multiinstitutional review of blunt abdominal trauma and studied 230 patients with blunt pancreatoduodenal injury.8 Ninety-seven (42%) of these were selected for nonoperative management and with a success rate of 90%. A study from the Nationwide Inpatient Sample shows that over a 10-year period from 1998 to 2009 the number of pancreatoduodenal injuries increased by 8.3%; however, the proportion of patients receiving operative intervention declined from 21.7% to 19.8% without affecting morbidity.9 ERCP can be a very useful adjunct in the diagnosis and management of lowgrade pancreatic injuries.10
INTRAOPERATIVE EVALUATION After hemorrhage is controlled in the management of pancreatic trauma, delayed complications, such as pancreatic fistulae and pseudocysts, intraabdominal abscesses, and multisystem organ dysfunction, correlate in frequency with the severity of the pancreatic injury. Therefore the most extensive surgical procedures in the management of pancreatic trauma are reserved for patients with combined pancreaticoduodenal injuries. The overall goals of these surgical procedures are to (1) maintain pancreaticenteric and biliary-enteric flow, (2) provide wide drainage for all pancreatic and duodenal injuries and anastomoses, and (3) divert the gastrointestinal stream so as to minimize stimulation of the pancreaticobiliary secretions. In most patients with pancreatic injury, the diagnosis is confirmed intraoperatively. Evaluation of pancreatic trauma requires several surgical maneuvers. A Kocher maneuver entails incising the lateral peritoneal attachments
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FIGURE 102.2 Any hematomas overlying the gland must be unroofed.
FIGURE 102.3 With the peritoneum along the inferior border of the pancreas divided, the surgeon’s finger is slipped behind the gland to evaluate for palpable parenchymal defects.
to the second and third portion of the duodenum and mobilizing the duodenum and the head of the pancreas to the patient’s left. This proceeds along the avascular plane to the superior mesenteric vein. A replaced right hepatic artery is occasionally encountered as a branch of the superior mesenteric artery (SMA), and care must be taken because it can be injured during the dissection. This facilitates inspection of the posterior aspect of the head of the gland, as well as the posterior wall of the duodenum, and provides a view of the suprarenal inferior vena cava. The anterior aspect of the entire gland may be evaluated by entering the lesser sac through the gastrocolic omentum. With a wide incision through the omentum and retraction of the stomach superiorly and the transverse colon inferiorly, a thorough evaluation of the gland becomes possible. Any hematomas overlying the gland must be evacuated and thoroughly explored because they frequently mask underlying severe pancreatic parenchymal or ductal injury (Fig. 102.2). A patient may occasionally present with severe injury to the posterior aspect of the pancreas, with the anterior capsule intact. This is seen most commonly in patients with blunt mechanisms of injury. When hematoma or contusion raises an index of suspicion for injuries that may involve the posterior aspect of the gland, an incision should be made in the peritoneum and areolar tissue along the inferior aspect of the pancreas. Most of these injuries will reside in the prevertebral region of the pancreas. After division of the peritoneum along the inferior border of the pancreas, the surgeon’s finger is slipped behind the gland to evaluate for parenchymal defects by palpation and direct visualization (Fig. 102.3). Full evaluation of the tail of the pancreas can be facilitated by the Aird maneuver.11 Originally described in 1955
FIGURE 102.4 Aird maneuver is used to mobilize the spleen and tail of the pancreas.
to facilitate adrenalectomy, this procedure entails division of the avascular splenic ligaments (i.e., splenorenal, splenocolic and splenophrenic) and mobilization of the spleen and the tail of the pancreas from the patient’s left to right (Fig. 102.4).
Pancreatic Trauma CHAPTER 102
OPERATIVE TREATMENT AAST pancreatic organ injury scale grades injuries from I through V (Table 102.1).12 The use of a combination of the injury grade, injury location, and other concomitant injuries (especially to the duodenum) helps to determine the surgical treatment for the pancreatic injury. Patients with lower-grade pancreatic injuries are significantly easier to manage. Observation and drainage along with débridement and meticulous hemostasis may be all that is necessary for grade I (minor contusion or superficial laceration) or grade II injuries (major contusion or laceration). Major disruption of the pancreatic tissue requires a decision regarding the likelihood of major ductal injury. Even in major trauma centers, the gold standard ERCP is not available intraoperatively in the middle of the night. Suspicion of ductal involvement is raised by the anatomic location of the injury and the amount of local pancreatic tissue disruption. Pancreatic juice can occasionally be seen leaking at the open ends of a duct. When major ductal injury is suspected, it should, in most instances, prompt definitive therapy. Under some circumstances, such as cardiovascular instability, drainage alone should be performed, after which the patient almost always has a pancreatic fistula. The popular concept of a continuum of resuscitative care in the operating room/surgical intensive care unit, the acceptance of distal pancreatectomy for wounds to the left of the SMA, and the availability of postoperative ERCP in patients with more severe injuries who have been adequately drained, all render intraoperative pancreatography rarely indicated. In the rare instance when the duodenum is open already from the traumatic injury, then it is reasonable to perform fluoroscopic pancreatography by cannulating the ampulla to inject contrast. If there is no associated duodenal wound, the duodenum should not be opened
TABLE 102.1 American Association for the Surgery of Trauma Organ Injury Scaling: Pancreas Type of Injury
GRADE I
Hematoma Laceration
Minor contusion without duct injury Superficial laceration without duct injury
GRADE II Hematoma Laceration
Major contusion without duct injury or tissue loss Major laceration without duct injury or tissue loss
GRADE III Hematoma
Distal transection or parenchymal injury with duct injury
GRADE IV Laceration
Proximal transection or parenchymal injury involving ampulla
GRADE V Laceration
Massive disruption of pancreatic head
From Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling, II: pancreas, duodenum, small bowel, colon, and rectum. J Trauma. 1990;30(11):1427–1429.
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for the sole reason of performing a pancreatogram. Another technique for performing a pancreatogram is a cystic duct cholangiogram by passing the catheter into the common bile duct and refluxing contrast into the main pancreatic duct. Such adjuncts as secretin or intravenous opiates may enhance the ability to perform a pancreatogram in this fashion. After the pancreatic injury has been identified, the location of the injury will determine the appropriate treatment. The pancreatic duct injury can be divided into proximal (at the head or neck, to the right side of the superior mesenteric vessels) and distal injuries (at the distal body and tail to the left side of the mesenteric vessels). Grade III pancreatic injury with a distal transection or parenchymal injury is most easily treated by distal pancreatectomy. In the case of active ongoing hemorrhage, the most expeditious way to perform this is in combination with a splenectomy. The spleen and pancreatic tail will have already been mobilized, leaving only the division of the pancreas itself, the short gastric arteries, splenic artery, and splenic vein. As with all other operations on the pancreas for trauma, the area should be widely drained with closed-suction drains to manage possible postoperative pancreatic leak. Many options (including staples, sutures, or electrocautery) are acceptable for transecting the pancreas and controlling the transected end of the gland; their use is based on surgeon preference. Ideally the transected pancreatic duct should be identified and closed directly, often with either U stitch or a figure-of-eight suture. Other options include omental patch or fibrin glue for helping control the distal pancreatic stump. The possibility of a distal pancreatectomy without splenectomy (spleenpreserving distal pancreatectomy) can be considered in certain patient populations based on clinical stability and isolated injuries. The small benefit of helping to prevent overriding postsplenectomy sepsis by leaving the spleen in is often outweighed by the significant time that it takes to perform this tedious operation (Fig. 102.5). An extended distal pancreatectomy can be performed if the laceration resides to the right of the superior mesenteric vessels and may be an option that potentially avoids a Whipple procedure. Another alternative is a central pancreatectomy, which can be considered in the setting of a proximal ductal transection with otherwise normal distal pancreatic parenchyma. The procedure involves resecting the central portion of the gland and débriding back to viable tissue to properly close the end of the proximal duct. The distal pancreatic remnant is then drained by creating a Roux-en-Y pancreaticojejunostomy. Again, wide drainage should be performed to control a postoperative fistula. Surgical management of severe injuries to the pancreaticoduodenal complex are some of the most complex that a trauma surgeon deals with. These grades IV and V injuries involve proximal ductal injury or massive destruction of the pancreatic head to the right of the superior mesenteric vein and are often in close association with the C-loop of the duodenum. The scope of procedure performed varies with the severity of the injury, reserving the most aggressive surgical treatments for the most severe of these combined pancreaticoduodenal injuries.
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There are three main goals in any surgical procedure for severe pancreatic injury. The first is to maintain enteric flow from the pancreas to the biliary tree. The second is to divert any gastrointestinal secretions to minimize stimulation of the pancreatic exocrine function. The third is to widely drain in anticipation of postoperative leaks or fistulas. The main surgical dictum for treatment of the injuries should be to perform the minimal surgical intervention necessary to adequately treat the injury and accomplish these objectives. Significant injuries to the
FIGURE 102.5 Distal pancreatectomy with splenic preservation.
head and neck that do not injure the major pancreatic duct are most appropriately treated with simple débridement and drainage. This approach can be used in the hemodynamically unstable patient undergoing damage control surgery as a temporizing measure, allowing further investigation, such as ERCP or MRCP, after the initial operation. In the patient who is hemodynamically stable or at the second-stage operation after initial damage control, there are multiple options for dealing with injuries to the pancreaticoduodenal complex. If at the initial operation the pancreas is widely drained and the abdomen is closed, postoperative ERCP is performed to place a pancreatic stent (Fig. 102.6). This can give the main pancreatic duct injury time to heal without performing a major pancreatic resection. When pancreatic injuries are associated with major duodenal injuries, drainage or resection of pancreas can be combined with suturing or stapling of the pylorus (pyloric exclusion procedure) to divert gastric flow from the duodenum. Gastrointestinal continuity is then accomplished by gastrojejunostomy (Fig. 102.7). It is quite
FIGURE 102.6 The same patient as Fig. 102.1 following placement of a pancreatic stent.
FIGURE 102.7 The pyloric exclusion procedure.
Pancreatic Trauma CHAPTER 102
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concept that somatostatin may reduce the volume of output (and promote closure) after a pancreatic fistula has developed. Rarely, late management of the pancreatic fistula that shows no sign of closure after many weeks of nonoperative management or the patient who forms a pseudocyst after drain removal requires internal drainage via a Roux-en-Y jejunal limb. Postoperative pancreatic abscess usually demands open débridement and wide drainage. However, single uniloculated collections in the absence of much pancreatic necrosis (as determined by dynamic CT scanning) may respond to percutaneous CT-guided drainage with large catheters. Pulmonary and infectious complications also remain high at 20% and 13%, respectively, and need to be identified and managed appropriately.9 Literature shows that the risk factors for postoperative complications include age, injury location, injury grade, associated vascular injuries, and delay to surgery and are predictors of morbidity.9,15,16 FIGURE 102.8 The Whipple procedure mobilizing the head of the gland.
remarkable that gastroduodenal continuity is reestablished by 4 to 6 weeks after pyloric exclusion even when heavy nonabsorbable sutures or staples are used. The pyloric exclusion procedure has largely replaced the duodenal diverticulization procedure, which entails antrectomy and gastrojejunostomy, as well as drainage and decompression of the duodenal injury and drainage of the pancreatic injury. When pancreaticoduodenal trauma is so severe that hemorrhage control or extensive destruction of the tissue necessitates resection of the second portion of the duodenum or the head of the pancreas, a pancreaticoduodenectomy (Whipple procedure) is indicated. The avascular plane between the neck of the pancreas and the superior mesenteric vein allows for safe mobilization of the gland for resection (Fig. 102.8). A staged Whipple may be the safest option for the patient after hemorrhage and enteric contamination are controlled because peripancreatic packing and drainage are safe and effective temporary measures until the patient’s physiology is restored.13
POSTOPERATIVE CONSIDERATIONS When drainage is performed for major pancreatic injuries, the guideline for removing the drain is tolerance of regular tube feedings and the absence of high-volume or highamylase content in the drainage fluid. A feeding jejunostomy is an important adjunct to major pancreatic injuries requiring pancreatic resection, pyloric exclusion, or the Whipple procedure because accumulated evidence shows the importance of early enteric feeding in maintaining the immune function of the gut in critically injured patients. Up to one-third of patients with major pancreatic injuries develop a pancreatic fistula. Most of these resolve spontaneously with adequate drainage. The evidence of a beneficial effect of somatostatin following pancreatic resection for trauma fails to justify the expense associated with its routine use.14 There is more support for the
SUMMARY Pancreatic trauma continues to carry a significant risk of mortality and morbidity. Therefore treating other injuries to stabilize the patient may be necessary before definitive operative management of the pancreatic injury can occur. Prompt diagnosis, appropriate resuscitation, and careful surgical technique are paramount in the proper treatment of pancreatic trauma. The grade of the injury, and particularly the presence and location of a pancreatic ductal injury, determines the most appropriate operation (hemostasis, debridement, drainage versus resection, pyloric exclusion, or rarely pancreaticoduodenectomy). Finally, complications are likely to occur, so close observation and early interventions are essential to the recovery of patients with pancreatic trauma.
ACKNOWLEDGMENTS This chapter is an update from the prior chapters on pancreatic trauma by Edward E. Cornwell III, Elliot R. Haut, and David Kuwayama from the 6th edition of Shackelford’s Surgery of the Alimentary Tract and by Amy Rushing, Edward E. Cornwell III, and Elliott R. Haut from the 7th edition of Shackelford’s Surgery of the Alimentary Tract.
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results of a multicenter AAST study. J Trauma. 2009;66(3):641-646; discussion 646-647. 7. Bokhari F, Phelan H, Holevar M, et al. EAST Guidelines for the Diagnosis and Management of Pancreatic Trauma. Chicago: Eastern Association for the Surgery of Trauma (EAST); 2009. 8. Velmahos GC, Tabbara M, Gross R, et al. Blunt pancreatoduodenal injury: a multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT). Arch Surg. 2009;144(5):413419; discussion 419-420. 9. Ragulin-Coyne E, Witkowski ER, Chau Z, et al. National trends in pancreaticoduodenal trauma: interventions and outcomes. HPB (Oxford). 2014;16(3):275-281. 10. Rogers SJ, Cello JP, Schecter WP. Endoscopic retrograde cholangiopancreatography in patients with pancreatic trauma. J Trauma. 2010;68(3):538-544.
11. Aird I, Helman P. Bilateral anterior transabdominal adrenalectomy. Br Med J. 1955;2(4941):708-709. 12. Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling, II: pancreas, duodenum, small bowel, colon, and rectum. J Trauma. 1990;30(11):1427-1429. 13. Seamon MJ, Kim PK, Stawicki SP, et al. Pancreatic injury in damage control laparotomies: is pancreatic resection safe during the initial laparotomy? Injury. 2009;40(1):61-65. 14. Nwariaku FE, Terracina A, Mileski WJ, Minei JP, Carrico CJ. Is octreotide beneficial following pancreatic injury? Am J Surg. 1995; 170(6):582-585. 15. Recinos G, DuBose JJ, Teixeira PG, Inaba K, Demetriades D. Local complications following pancreatic trauma. Injury. 2009;40(5):516-520. 16. Lin BC, Chen RJ, Fang JF, Hsu YP, Kao YC, Kao JL. Management of blunt major pancreatic injury. J Trauma. 2004;56(4):774-778.