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Classification of liver and pancreatic trauma
HPB, 2006; 8: 4 /9
REVIEW ARTICLE
Classification of liver and pancreatic trauma
GABRIEL C. ONISCU, ROWAN W. PARKS & O. JAMES GARDEN Department of Surgery, University of Edinburgh, Edinburgh, UK
Abstract The liver is the most frequently injured intra-abdominal organ and associated injury to other organs increases the risk of complications and death. This has highlighted the critical need for an accurate classification system as a basis for the clinical decision-making process. Several classification systems have been proposed in an attempt to incorporate the aetiology, anatomy and extent of injury and correlate it with subsequent clinical management and outcome. The widely accepted Organ Injury Scale is based on anatomical criteria that quantify the disruption of the liver parenchyma and defines six groups which may influence management strategies and relate to outcome. The less common pancreatic injury remains a major source of morbidity and mortality due to the likelihood of associated solid or hollow-organ injuries. The implication of a delay in diagnosis and management emphasizes the need for an accurate classification system. The Organ Injury Scale is widely used for pancreas trauma and recognizes the importance of progressive parenchymal injury and in particular ductal injury. Advances in imaging techniques have led to the development of newer radiological classification systems; however, validation of their accuracy remains to be proven. An accurate classification of liver and pancreatic trauma is fundamental for the development of treatment protocols in which clinical decisions are based on the severity of injury.
Key Words: Liver injury, pancreatic injury, classification system, Organ Injury Scale
Introduction Hepatobiliary and pancreatic trauma represent a significant management challenge for the emergency surgeon and specialist alike. These injuries require a high index of suspicion, rapid investigation, accurate classification and well-defined management protocols to ensure an optimal outcome with minimal long-term consequences. Despite its relatively protected location, the liver is the most frequently injured intra-abdominal organ [1]. The risk of uncontrolled haemorrhage, development of late complications and associated injury to other organs contribute significantly to the high morbidity and mortality. Furthermore, the myriad of presentations and the combination of different types of injury make liver trauma a complex and challenging management issue. Conversely, pancreatic trauma is rare and its presentation is usually occult, but the association with injury to other organs and the mechanism of trauma is the key to appropriate investigation, accurate diagnosis and useful classification.
The management of trauma patients has evolved significantly over the last three decades and is based on well defined protocols. Therefore, a classification system that can define the mechanism and extent of injuries and allow appropriate treatment to be formulated according to the type of injury is essential to ensure a successful outcome in these complex cases. Furthermore, a universally accepted classification allows for meaningful comparisons of published data. This paper discusses the various classification schemes proposed for liver and pancreatic trauma and reviews the evidence supporting their use in establishing management protocols and in correlating various injuries with outcome. Classification of liver trauma Rationale and principles of liver trauma classification The number of liver injuries has increased significantly over the last 25 years, mainly as a result of the continuing increase in trauma cases. Due to the complexity of hepatic structure, liver trauma can
Correspondence: O. James Garden, Regius Professor of Surgery, Department of Surgery, University of Edinburgh, Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA, UK. Tel: /44 (0) 131 242 3614. Fax: /44 (0) 131 242 3617. E-mail: [email protected]
ISSN 1365-182X print/ISSN 1477-2574 online # 2006 Taylor & Francis DOI: 10.1080/13651820500465881
Classification of liver and pancreatic trauma present with a variety of clinical pictures ranging from minor capsular tears to extensive parenchymal disruption with associated hepatic or vena cava injury. Whilst some of the minor injuries can be incidental findings during investigation, patients with major hepatic trauma may present with profound clinical shock and abdominal distension, requiring rapid resuscitation and immediate operative management. Clearly, liver trauma has the potential for extensive injuries which must be carefully recognized and classified to ensure adequate management. Over the last three decades there have been significant developments as well as changes in the management of liver trauma [2]. Although it is widely accepted that penetrating injuries require operative treatment [3], there is no absolute agreement regarding the management of blunt injuries. Prior to 1990 most blunt injuries were treated surgically to ensure haemostasis and because of concerns regarding biliary leaks and sepsis. It is now widely accepted that 50 /80% of liver injuries stop bleeding spontaneously and therefore a conservative approach is effective and relatively safe in haemodynamically stable patients who can be closely observed [2,4,5]. Severe hepatic injuries in unstable patients require surgical intervention and several techniques have been described to control bleeding and deal with extensive parenchymal damage. It is important to highlight that often these patients present to the emergency surgeon without specialist hepatobiliary experience and without the facilities available in liver surgical units. In such cases, recognition of the extent of the injury according to an accurate and widely accepted classification system is essential to ensure the optimal management by the appropriate team. The grading (classification) of liver trauma is also essential in any discussion regarding outcome, as this is related not only to the nature and extent of the injury but also to the severity of any concomitant injury [6]. It is important to highlight that in the last decade, most studies have reported a significant correlation between the grade of injury and outcome, with those patients having a higher injury score being less likely to survive [3,7 /11]. In view of the complex clinical picture and the variety of treatment options, any modern classification scheme for liver trauma should be able to fulfil a series of general principles. First of all, it should be able to identify the mechanism of trauma as well as the extent and anatomical details of the injuries. Secondly, it should be able to recognize distinctive groups of
injuries, which could be correlated with a certain management strategy, either conservative or surgical. Thirdly, the different grades of trauma should be linked with the likelihood of further complications and potential outcome. Last but not least, any classification has to be objective and reproducible, and must have prospective as well as retrospective applicability to allow for meaningful comparisons. Reported schemes for the classification of liver trauma The earliest classification of liver trauma was based on the mechanism of injury and was not refined as surgical intervention was the norm. Injuries were defined as either blunt (crushing or shearing) or penetrating (stabbing or gunshot). Although this simple scheme identified the mechanism of injury, it did not satisfy the principles laid out previously. Classification based on the extent of injury and intraoperative findings With a better understanding of the anatomy of the liver and a growing number of reports documenting a variable outcome depending on the type of liver injury, it became apparent that the amount of parenchymal damage and/or vascular involvement had a significant impact on the management and outcome of liver trauma. Several schemes were proposed in the 1970 /1980s [7,8,12 /15]. These different classification schemes highlighted that minimal parenchymal damage was associated with low morbidity and mortality. In a large series of 1000 cases, Feliciano and colleagues [7] quoted a 7% overall mortality for simple liver injuries but reported a much higher mortality for injuries requiring ‘complex repair’ procedures. In this later group the mortality was approximately 34%, a figure comparable to that reported by others [8,12]. However, these schemes lacked uniformity in reporting of data and made comparison impossible. Anatomical classification In 1990, Buechter et al. [16] acknowledged the correlation between outcome and the extent of the parenchymal damage together with the magnitude of surgical procedure required to treat the injury. He proposed a three grade classification system based on the segmental anatomy of the liver as defined by Couinaud (Table I).
Table I. Buechter classification of liver trauma. Grade* I II III
5
Injury description Injuries requiring no operative intervention, or any injury that requires operative intervention limited to a segment or less Any injury that requires operative intervention involving two or more segments Any injury with an associated juxta- or retro-hepatic vein injury
6
G. C. Oniscu et al.
Buechter suggested that the extent of parenchymal damage could be quantified by the number of liver segments involved and concluded that trauma involving two or more segments was associated with a significantly worse prognosis. Furthermore, there appeared to be a direct correlation between morbidity and mortality rates and the volume of damaged hepatic tissue. This scheme provided a reproducible but rather simplistic way of reporting and comparing liver trauma, concentrating on the anatomical and operative aspects of the liver injury with minimal attention to the extent of vascular injuries. In addition, it was not very clear which injuries might benefit from a conservative approach to treatment which began to be more widely adopted in the early 1990s. Vascular injury classification Early classification systems acknowledged that ultimately the extent of vascular injury, rather than the magnitude of the parenchymal damage, was the principal prognostic factor in patients with liver trauma. In 1994, Namieno et al. [17] proposed a new three grade classification based on vessel injury: grade I, subcapsular Glissonian vessel injuries; grade II, transcapsular Glissonian vessel injuries; and grade III, in-/out-flow vessel injuries. However, Namieno’s classification did not have a significant impact as it concentrated mainly on the extent of the vascular injuries and failed to acknowledge that extensive parenchymal damage may well have a comparable outcome with some of the lesser vascular lesions. Organ Injury Scale (AAST) classification In the late 1980s, trauma surgery became better defined and standardized management protocols were introduced, such as Advanced Trauma Life Support (ATLS). In 1989 the Organ Injury Scaling Committee of the American Association for the
Surgery of Trauma (AAST) defined the most comprehensive hepatic injury classification to date [18].This classification system described five grades of injury from I (the least severe) to V (the most severe) and was essentially an anatomical one. A VI grade was added to identify injuries which were incompatible with survival. Severity was based on the potential threat to a patient’s life, but the declared aim of the scheme was to provide a clear description of injuries rather than to generate prognostic values for a particular grade of trauma. This classification system was facilitated by the introduction of CT scanning and incorporated both preoperative and intraoperative assessment of the extent of hepatic injury. Since its publication, the AAST classification system has been regarded as the standard by which hepatic injuries are described. However, the scheme has been criticized for the lack of an anatomical definition, failing to include the Couinaud segmental anatomy to quantify the extent of the injury as in the Buechter classification. Progress in the management of severe hepatic trauma also highlighted the need for better defined criteria for grade IV and V injuries, in order to highlight the technical challenges posed by these lesions. Furthermore, with the widespread availability of CT scanning, there was a sizeable body of evidence suggesting a more benign clinical course than initially thought for haematomas and as a consequence, the classification system was revised in 1994 [19] (Table II). The specific changes included: an increased threshold for haematomas to /10 cm for grade III; an increased amount of parenchyma involvement to /75% for grade V; the addition of Couinaud segments for grade IV and V. With the introduction of the AAST classification and supported by the widespread use of CT scanning, the reporting of various studies had a common denominator. The experience accumulated with this standardized classification allowed for a significant shift in the management of liver trauma with a predilection for a non-operative management
Table II. AAST liver injury scale (1994 revision). Grade* I
III
Haematoma Laceration Haematoma Laceration Haematoma
IV
Laceration Laceration
V
Laceration
VI
Vascular Vascular
II
Injury description Subcapsular, B/10% surface Capsular tear, B/1 cm parenchymal depth Subcapsular, 10 /50% surface area; intra-parenchymal, B/10 cm in diameter 1 /3 cm parenchymal depth, B/10 cm in length Subcapsular, /50% surface area or expanding; ruptured subcapsular or parenchymal haematoma Intraparenchymal haematoma /10 cm or expanding / 3 cm parenchymal depth Parenchymal disruption involving 25 /75% of hepatic lobe or 1 /3 Couinaud’s segments within a single lobe Parenchymal disruption involving /75% of hepatic lobe or /3 Couinaud’s segments within a single lobe Juxtavenous hepatic injuries; i.e. retrohepatic vena cava/central major hepatic veins Hepatic avulsion
*Advance one grade for multiple injuries, up to grade III.
Classification of liver and pancreatic trauma
7
Table III. Lucas classification of pancreatic injuries. Grade I II III
Figure 1. CT scan showing liver trauma with a large haematoma in segment 7 extending to the capsule and associated perihepatic haematoma.
Injury description Superficial contusion with minimal damage Deep laceration or transection of the left portion of the pancreas Injury of the pancreatic head
going surgery and concluded that even major hepatic trauma, as defined by grade 4 on the CT scheme, could be managed without surgery in haemodynamically stable patients. These findings have been supported by recent reports [11,21,23], which have concluded that CT scanning is an essential part of an accurate classification. Classification of pancreatic trauma
approach even in selected patients with blunt grade IV and V hepatic injuries [4,20]. The additional benefits of this classification were a correlation between the degree of injury and outcome [10,11], and the ease of quantification of associated injuries using similarly devised Organ Injury Scales.
Radiological classification There is no doubt that the introduction and refinement of CT scanning has had the greatest impact on the classification and subsequent management of liver trauma [20]. CT scanning is able to identify subcapsular or central haematomas, contusions, periportal tracking of fluid, complex lacerations and fragmentation or avulsions of the hepatic pedicle [21] (Figure 1). Despite the AAST classification incorporating extensive preoperative assessment data derived from the CT examination, the perceived benefit of this investigation, especially in blunt trauma, has led to the development of additional CT-based classification schemes. In 1989 Mirvis et al. [22] proposed a five grade CT-based scheme of hepatic injury, varying from capsular avulsion, superficial lacerations, subcapsular haematoma and periportal tracking to major parenchymal damage and vascular injury. This group compared the radiological findings with the clinical outcome in patients managed conservatively as well as those patients under-
Although less common than liver trauma, pancreatic injuries should be suspected in any patient with penetrating trauma to the trunk or following blunt compression of the upper abdomen [24]. The principles outlined for classification of liver trauma are equally applicable to classification of pancreatic trauma, but the additional critical element that must be acknowledged is the presence of injury to the pancreatic duct. Bradley et al. [25] demonstrated that there is a significant association between injury to the main pancreatic duct and pancreas-related morbidity. Furthermore, delayed intervention due to late recognition of these injuries was associated with high morbidity. In an early report, Lucas [26] suggested that appropriate treatment should be formulated according to the type of injury and therefore he subdivided pancreatic injuries into three groups (Table III). Although, this scheme is very succinct, it does not acknowledge the prognostic significance of a pancreatic duct injury. In 1990, the AAST expanded the Organ Injury Scale to include injuries to the pancreas, duodenum and bowel [27]. This five grade scheme (Table IV) acknowledges the significance of more complex injuries to the pancreas, and in particular those injuries affecting the pancreatic duct and the head of the gland. Furthermore, this classification system allowed correlation with other organ injury scales, as well as
Table IV. AAST classification of pancreatic trauma. Grade I II III IV V
Haematoma Laceration Haematoma Laceration Laceration Laceration Laceration
Injury description Minor contusion without ductal injury Superficial laceration without ductal injury Major contusion without ductal injury or tissue loss Major laceration without ductal injury or tissue loss Distal transection or pancreatic parenchymal injury with ductal injury Proximal transection or pancreatic parenchymal injury involving the ampulla Massive disruption of the pancreatic head
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G. C. Oniscu et al.
Table V. Frey and Wardell classification of pancreatic trauma. Grade and location of injury Pancreas Class I (P1) Class II (P2) Class III (P3) Duodenum Class I (D1) Class II (D2) Class III (D3)
Combined Type I Type II Type III Type IV
Injury description
Capsular damage, minor parenchymal damage Partial/complete duct transection in the body/tail Major duct injury involving the head of pancreas or the intrapancreatic common bile duct Contusion, haematoma or partial thickness injury Full thickness duodenal injury Full thickness injury with / 75% circumference injury or injury to the extrahepatic common bile duct P1D1, P2D1, D2P1 D2P2 D3P1 2, P3D1 2 D3P3
integration into more complex scoring systems, such as Injury Severity Score (ISS) or Trauma Score / Injury Severity Score (TRISS), which determine the probability of survival for an individual patient. The frequent association between pancreatic and duodenal trauma and the implications for the definitive management of these associated injuries has been recognized by Frey and Wardell [28], who proposed a complex classification system. They defined degrees of pancreatic trauma and duodenal trauma separately (Table V) and established four types of combined injuries with increasing severity that correlated with poorer outcome. As with liver trauma, CT scanning is the main diagnostic procedure used to identify pancreatic trauma (Figure 2); however, there is evidence that CT is not very accurate in detecting pancreatic duct injuries [25,29]. Given the prognostic value of the ductal injury, endoscopic retrograde pancreatography (ERP) is currently the gold standard procedure for the characterization of the pancreatic duct. Takishima et al. [30] have used this to describe a three class
classification of pancreatic ductal injuries: class 1, radiographically normal duct; class 2a, contrast from branch injuries does not leak outside the pancreatic parenchyma; class 2b / contrast from branch injuries leaks into the retroperitoneal space; class 3: main duct injuries. Takishima correlated the classification scheme with subsequent surgical management and concluded that class 1 and class 2a injuries could be treated nonoperatively with minimal risk of complications, while all other injuries required a laparotomy and at least a drainage procedure. Although most pancreatic injuries are detected intraoperatively, it is important to have an accurate classification, even if this is established at laparotomy, to ensure adequate treatment of the pancreatic trauma and any other associated injury. Conclusion An accurate classification of hepatic and pancreatic injuries is an essential step in the management of trauma patients. A precise grading system must be guided by the mechanism, anatomy and extent of the injuries and should correlate with a treatment strategy and subsequent outcome. The Organ Injury Scale proposed by the AAST fulfils most of these criteria and at present is the universally accepted classification scheme, which allows meaningful comparisons of the literature and guides further development of management protocols.
References [1] Feliciano DV. Surgery for liver trauma. Surg Clin North Am 1989;69:273 /84. [2] David RJ, Franklin GA, Lukan JK, Carrillo EH, Spain DA, Miller FB, et al. Evolution in the management of hepatic trauma: a 25-year perspective. Ann Surg 2000;232:324 /30. /
Figure 2. CT scan showing pancreatic body and tail trauma with associated splenic artery pseudoaneurysm.
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Classification of liver and pancreatic trauma [3] Cogbill TH, Moore EE, Jurkovich GJ, Feliciano DV, Morris JA, Mucha P. Severe hepatic trauma: a multi-center experience with 1,335 liver injuries. J Trauma 1988;28:1433 /8. [4] Croce MA, Fabian TC, Menke PG, Waddle-Smith L, Minard G, Kudsk KA, et al. Nonoperative management of blunt hepatic trauma is the treatment of choice for hemodynamically stable patients. Results of a prospective trial. Ann Surg 1995; 221:744 /53. [5] Pachter HL, Hofstetter SR. The current status of nonoperative management of adult blunt hepatic injuries. Am J Surg 1995; 169:442 /54. [6] Menegaux F, Langlois P, Chigot JP. Severe blunt trauma of the liver: study of mortality factors. J Trauma 1993;35:865 /9. [7] Feliciano DV, Mattox KL, Jordan GL Jr, Burch JM, Bitondo CG, Cruse PA. Management of 1000 consecutive cases of hepatic trauma (1979 /1984). Ann Surg 1986;204:438 /45. [8] Pachter HL, Spencer FC, Hofstetter SR, Coppa GF. Experience with the finger fracture technique to achieve intra-hepatic hemostasis in 75 patients with severe injuries of the liver. Ann Surg 1983;197:771 /8. [9] Gur S, Orsel A, Atahan K, Hokmez A, Tarcan E. Surgical treatment of liver trauma (analysis of 244 patients). Hepatogastroenterology 2003;50:2109 /11. [10] Malhotra AK, Latifi R, Fabian TC, Ivatury RR, Dhage S, Bee TK, et al. Multiplicity of solid organ injury: influence on management and outcomes after blunt abdominal trauma. J Trauma 2003;54:925 /9. [11] Matthes G, Stengel D, Seifert J, Rademacher G, Mutze S, Ekkernkamp A. Blunt liver injuries in polytrauma: results from a cohort study with the regular use of whole-body helical computed tomography. World J Surg 2003;27:1124 /30. [12] Moore FA, Moore EE, Seagraves A. Nonresectional management of major hepatic trauma. An evolving concept. Am J Surg 1985;150:725 /9. [13] Aldrete JS, Halpern NB, Ward S, Wright JO. Factors determining the mortality and morbidity in hepatic injuries. Analysis of 108 cases. Ann Surg 1979;189:466 /74. [14] Cox EF, Flancbaum L, Dauterive AH, Paulson RL. Blunt trauma to the liver. Analysis of management and mortality in 323 consecutive patients. Ann Surg 1988;207:126 /34. [15] Ivatury RR, Nallathambi M, Gunduz Y, Constable R, Rohman M, Stahl WM. Liver packing for uncontrolled hemorrhage: a reappraisal. J Trauma 1986;26:744 /53. [16] Buechter KJ, Zeppa R, Gomez G. The use of segmental anatomy for an operative classification of liver injuries. Ann Surg 1990;211:669 /73. /
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[17] Namieno T, Hata Y, Uchino J, Matsubara I, Tedo I. Blunt liver trauma: a new concept for classification of liver trauma based on vessel injury. Int Surg 1994;79:52 /9. [18] Moore EE, Shackford SR, Pachter HL, McAninch JW, Browner BD, Champion HR, et al. Organ injury scaling: spleen, liver, and kidney. J Trauma 1989;29:1664 /6. [19] Moore EE, Cogbill TH, Jurkovich GJ, Shackford SR, Malangoni MA, Champion HR. Organ injury scaling: spleen and liver. J Trauma ;38 1994;1995:323 /4. [20] Boone DC, Federle M, Billiar TR, Udekwu AO, Peitzman AB. Evolution of management of major hepatic trauma: identification of patterns of injury. J Trauma 1995;39:344 /50. [21] Romano L, Giovine S, Guidi G, Tortora G, Cinque T, Romano S. Hepatic trauma: CT findings and considerations based on our experience in emergency diagnostic imaging. Eur J Radiol 2004;50:59 /66. [22] Mirvis SE, Whitley NO, Vainwright JR, Gens DR. Blunt hepatic trauma in adults: CT-based classification and correlation with prognosis and treatment. Radiology 1989;171:27 / 32. [23] Poletti PA, Mirvis SE, Shanmuganathan K, Takada T, Killeen KL, Perlmutter D, et al. Blunt abdominal trauma patients: can organ injury be excluded without performing computed tomography? J Trauma 2004;57:1072 /81. [24] Johnson CD. Pancreatic trauma. Br J Surg 1995;82:1153 /4. [25] Bradley EL III, Young PR Jr, Chang MC, Allen JE, Baker CC, Meredith W, et al. Diagnosis and initial management of blunt pancreatic trauma: guidelines from a multiinstitutional review. Ann Surg 1998;227:861 /9. [26] Lucas CE. Diagnosis and treatment of pancreatic and duodenal injury. Surg Clin North Am 1977;57:49 /65. [27] Moore EE, Cogbill TH, Malangoni MA, Jurkovich GJ, Champion HR, Gennarelli TA, et al. Organ injury scaling, II: Pancreas, duodenum, small bowel, colon, and rectum. J Trauma 1990;30:1427 /9. [28] Frey CF, Wardell JW. Injuries to the pancreas. In: Trede M, Carter DC, editors. Surgery of the pancreas. Edinburgh: Churchill Livingstone; 1993:565 /89. [29] Akhrass R, Yaffe MB, Brandt CP, Reigle M, Fallon WF Jr, Malangoni MA. Pancreatic trauma: a ten-year multi-institutional experience. Am Surg 1997;63:598 /604. [30] Takishima T, Hirata M, Kataoka Y, Asari Y, Sato K, Ohwada T, et al. Pancreatographic classification of pancreatic ductal injuries caused by blunt injury to the pancreas. J Trauma 2000;48:745 /51. /
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REVIEW ARTICLE
Classification of liver and pancreatic trauma
GABRIEL C. ONISCU, ROWAN W. PARKS & O. JAMES GARDEN Department of Surgery, University of Edinburgh, Edinburgh, UK
Abstract The liver is the most frequently injured intra-abdominal organ and associated injury to other organs increases the risk of complications and death. This has highlighted the critical need for an accurate classification system as a basis for the clinical decision-making process. Several classification systems have been proposed in an attempt to incorporate the aetiology, anatomy and extent of injury and correlate it with subsequent clinical management and outcome. The widely accepted Organ Injury Scale is based on anatomical criteria that quantify the disruption of the liver parenchyma and defines six groups which may influence management strategies and relate to outcome. The less common pancreatic injury remains a major source of morbidity and mortality due to the likelihood of associated solid or hollow-organ injuries. The implication of a delay in diagnosis and management emphasizes the need for an accurate classification system. The Organ Injury Scale is widely used for pancreas trauma and recognizes the importance of progressive parenchymal injury and in particular ductal injury. Advances in imaging techniques have led to the development of newer radiological classification systems; however, validation of their accuracy remains to be proven. An accurate classification of liver and pancreatic trauma is fundamental for the development of treatment protocols in which clinical decisions are based on the severity of injury.
Key Words: Liver injury, pancreatic injury, classification system, Organ Injury Scale
Introduction Hepatobiliary and pancreatic trauma represent a significant management challenge for the emergency surgeon and specialist alike. These injuries require a high index of suspicion, rapid investigation, accurate classification and well-defined management protocols to ensure an optimal outcome with minimal long-term consequences. Despite its relatively protected location, the liver is the most frequently injured intra-abdominal organ [1]. The risk of uncontrolled haemorrhage, development of late complications and associated injury to other organs contribute significantly to the high morbidity and mortality. Furthermore, the myriad of presentations and the combination of different types of injury make liver trauma a complex and challenging management issue. Conversely, pancreatic trauma is rare and its presentation is usually occult, but the association with injury to other organs and the mechanism of trauma is the key to appropriate investigation, accurate diagnosis and useful classification.
The management of trauma patients has evolved significantly over the last three decades and is based on well defined protocols. Therefore, a classification system that can define the mechanism and extent of injuries and allow appropriate treatment to be formulated according to the type of injury is essential to ensure a successful outcome in these complex cases. Furthermore, a universally accepted classification allows for meaningful comparisons of published data. This paper discusses the various classification schemes proposed for liver and pancreatic trauma and reviews the evidence supporting their use in establishing management protocols and in correlating various injuries with outcome. Classification of liver trauma Rationale and principles of liver trauma classification The number of liver injuries has increased significantly over the last 25 years, mainly as a result of the continuing increase in trauma cases. Due to the complexity of hepatic structure, liver trauma can
Correspondence: O. James Garden, Regius Professor of Surgery, Department of Surgery, University of Edinburgh, Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA, UK. Tel: /44 (0) 131 242 3614. Fax: /44 (0) 131 242 3617. E-mail: [email protected]
ISSN 1365-182X print/ISSN 1477-2574 online # 2006 Taylor & Francis DOI: 10.1080/13651820500465881
Classification of liver and pancreatic trauma present with a variety of clinical pictures ranging from minor capsular tears to extensive parenchymal disruption with associated hepatic or vena cava injury. Whilst some of the minor injuries can be incidental findings during investigation, patients with major hepatic trauma may present with profound clinical shock and abdominal distension, requiring rapid resuscitation and immediate operative management. Clearly, liver trauma has the potential for extensive injuries which must be carefully recognized and classified to ensure adequate management. Over the last three decades there have been significant developments as well as changes in the management of liver trauma [2]. Although it is widely accepted that penetrating injuries require operative treatment [3], there is no absolute agreement regarding the management of blunt injuries. Prior to 1990 most blunt injuries were treated surgically to ensure haemostasis and because of concerns regarding biliary leaks and sepsis. It is now widely accepted that 50 /80% of liver injuries stop bleeding spontaneously and therefore a conservative approach is effective and relatively safe in haemodynamically stable patients who can be closely observed [2,4,5]. Severe hepatic injuries in unstable patients require surgical intervention and several techniques have been described to control bleeding and deal with extensive parenchymal damage. It is important to highlight that often these patients present to the emergency surgeon without specialist hepatobiliary experience and without the facilities available in liver surgical units. In such cases, recognition of the extent of the injury according to an accurate and widely accepted classification system is essential to ensure the optimal management by the appropriate team. The grading (classification) of liver trauma is also essential in any discussion regarding outcome, as this is related not only to the nature and extent of the injury but also to the severity of any concomitant injury [6]. It is important to highlight that in the last decade, most studies have reported a significant correlation between the grade of injury and outcome, with those patients having a higher injury score being less likely to survive [3,7 /11]. In view of the complex clinical picture and the variety of treatment options, any modern classification scheme for liver trauma should be able to fulfil a series of general principles. First of all, it should be able to identify the mechanism of trauma as well as the extent and anatomical details of the injuries. Secondly, it should be able to recognize distinctive groups of
injuries, which could be correlated with a certain management strategy, either conservative or surgical. Thirdly, the different grades of trauma should be linked with the likelihood of further complications and potential outcome. Last but not least, any classification has to be objective and reproducible, and must have prospective as well as retrospective applicability to allow for meaningful comparisons. Reported schemes for the classification of liver trauma The earliest classification of liver trauma was based on the mechanism of injury and was not refined as surgical intervention was the norm. Injuries were defined as either blunt (crushing or shearing) or penetrating (stabbing or gunshot). Although this simple scheme identified the mechanism of injury, it did not satisfy the principles laid out previously. Classification based on the extent of injury and intraoperative findings With a better understanding of the anatomy of the liver and a growing number of reports documenting a variable outcome depending on the type of liver injury, it became apparent that the amount of parenchymal damage and/or vascular involvement had a significant impact on the management and outcome of liver trauma. Several schemes were proposed in the 1970 /1980s [7,8,12 /15]. These different classification schemes highlighted that minimal parenchymal damage was associated with low morbidity and mortality. In a large series of 1000 cases, Feliciano and colleagues [7] quoted a 7% overall mortality for simple liver injuries but reported a much higher mortality for injuries requiring ‘complex repair’ procedures. In this later group the mortality was approximately 34%, a figure comparable to that reported by others [8,12]. However, these schemes lacked uniformity in reporting of data and made comparison impossible. Anatomical classification In 1990, Buechter et al. [16] acknowledged the correlation between outcome and the extent of the parenchymal damage together with the magnitude of surgical procedure required to treat the injury. He proposed a three grade classification system based on the segmental anatomy of the liver as defined by Couinaud (Table I).
Table I. Buechter classification of liver trauma. Grade* I II III
5
Injury description Injuries requiring no operative intervention, or any injury that requires operative intervention limited to a segment or less Any injury that requires operative intervention involving two or more segments Any injury with an associated juxta- or retro-hepatic vein injury
6
G. C. Oniscu et al.
Buechter suggested that the extent of parenchymal damage could be quantified by the number of liver segments involved and concluded that trauma involving two or more segments was associated with a significantly worse prognosis. Furthermore, there appeared to be a direct correlation between morbidity and mortality rates and the volume of damaged hepatic tissue. This scheme provided a reproducible but rather simplistic way of reporting and comparing liver trauma, concentrating on the anatomical and operative aspects of the liver injury with minimal attention to the extent of vascular injuries. In addition, it was not very clear which injuries might benefit from a conservative approach to treatment which began to be more widely adopted in the early 1990s. Vascular injury classification Early classification systems acknowledged that ultimately the extent of vascular injury, rather than the magnitude of the parenchymal damage, was the principal prognostic factor in patients with liver trauma. In 1994, Namieno et al. [17] proposed a new three grade classification based on vessel injury: grade I, subcapsular Glissonian vessel injuries; grade II, transcapsular Glissonian vessel injuries; and grade III, in-/out-flow vessel injuries. However, Namieno’s classification did not have a significant impact as it concentrated mainly on the extent of the vascular injuries and failed to acknowledge that extensive parenchymal damage may well have a comparable outcome with some of the lesser vascular lesions. Organ Injury Scale (AAST) classification In the late 1980s, trauma surgery became better defined and standardized management protocols were introduced, such as Advanced Trauma Life Support (ATLS). In 1989 the Organ Injury Scaling Committee of the American Association for the
Surgery of Trauma (AAST) defined the most comprehensive hepatic injury classification to date [18].This classification system described five grades of injury from I (the least severe) to V (the most severe) and was essentially an anatomical one. A VI grade was added to identify injuries which were incompatible with survival. Severity was based on the potential threat to a patient’s life, but the declared aim of the scheme was to provide a clear description of injuries rather than to generate prognostic values for a particular grade of trauma. This classification system was facilitated by the introduction of CT scanning and incorporated both preoperative and intraoperative assessment of the extent of hepatic injury. Since its publication, the AAST classification system has been regarded as the standard by which hepatic injuries are described. However, the scheme has been criticized for the lack of an anatomical definition, failing to include the Couinaud segmental anatomy to quantify the extent of the injury as in the Buechter classification. Progress in the management of severe hepatic trauma also highlighted the need for better defined criteria for grade IV and V injuries, in order to highlight the technical challenges posed by these lesions. Furthermore, with the widespread availability of CT scanning, there was a sizeable body of evidence suggesting a more benign clinical course than initially thought for haematomas and as a consequence, the classification system was revised in 1994 [19] (Table II). The specific changes included: an increased threshold for haematomas to /10 cm for grade III; an increased amount of parenchyma involvement to /75% for grade V; the addition of Couinaud segments for grade IV and V. With the introduction of the AAST classification and supported by the widespread use of CT scanning, the reporting of various studies had a common denominator. The experience accumulated with this standardized classification allowed for a significant shift in the management of liver trauma with a predilection for a non-operative management
Table II. AAST liver injury scale (1994 revision). Grade* I
III
Haematoma Laceration Haematoma Laceration Haematoma
IV
Laceration Laceration
V
Laceration
VI
Vascular Vascular
II
Injury description Subcapsular, B/10% surface Capsular tear, B/1 cm parenchymal depth Subcapsular, 10 /50% surface area; intra-parenchymal, B/10 cm in diameter 1 /3 cm parenchymal depth, B/10 cm in length Subcapsular, /50% surface area or expanding; ruptured subcapsular or parenchymal haematoma Intraparenchymal haematoma /10 cm or expanding / 3 cm parenchymal depth Parenchymal disruption involving 25 /75% of hepatic lobe or 1 /3 Couinaud’s segments within a single lobe Parenchymal disruption involving /75% of hepatic lobe or /3 Couinaud’s segments within a single lobe Juxtavenous hepatic injuries; i.e. retrohepatic vena cava/central major hepatic veins Hepatic avulsion
*Advance one grade for multiple injuries, up to grade III.
Classification of liver and pancreatic trauma
7
Table III. Lucas classification of pancreatic injuries. Grade I II III
Figure 1. CT scan showing liver trauma with a large haematoma in segment 7 extending to the capsule and associated perihepatic haematoma.
Injury description Superficial contusion with minimal damage Deep laceration or transection of the left portion of the pancreas Injury of the pancreatic head
going surgery and concluded that even major hepatic trauma, as defined by grade 4 on the CT scheme, could be managed without surgery in haemodynamically stable patients. These findings have been supported by recent reports [11,21,23], which have concluded that CT scanning is an essential part of an accurate classification. Classification of pancreatic trauma
approach even in selected patients with blunt grade IV and V hepatic injuries [4,20]. The additional benefits of this classification were a correlation between the degree of injury and outcome [10,11], and the ease of quantification of associated injuries using similarly devised Organ Injury Scales.
Radiological classification There is no doubt that the introduction and refinement of CT scanning has had the greatest impact on the classification and subsequent management of liver trauma [20]. CT scanning is able to identify subcapsular or central haematomas, contusions, periportal tracking of fluid, complex lacerations and fragmentation or avulsions of the hepatic pedicle [21] (Figure 1). Despite the AAST classification incorporating extensive preoperative assessment data derived from the CT examination, the perceived benefit of this investigation, especially in blunt trauma, has led to the development of additional CT-based classification schemes. In 1989 Mirvis et al. [22] proposed a five grade CT-based scheme of hepatic injury, varying from capsular avulsion, superficial lacerations, subcapsular haematoma and periportal tracking to major parenchymal damage and vascular injury. This group compared the radiological findings with the clinical outcome in patients managed conservatively as well as those patients under-
Although less common than liver trauma, pancreatic injuries should be suspected in any patient with penetrating trauma to the trunk or following blunt compression of the upper abdomen [24]. The principles outlined for classification of liver trauma are equally applicable to classification of pancreatic trauma, but the additional critical element that must be acknowledged is the presence of injury to the pancreatic duct. Bradley et al. [25] demonstrated that there is a significant association between injury to the main pancreatic duct and pancreas-related morbidity. Furthermore, delayed intervention due to late recognition of these injuries was associated with high morbidity. In an early report, Lucas [26] suggested that appropriate treatment should be formulated according to the type of injury and therefore he subdivided pancreatic injuries into three groups (Table III). Although, this scheme is very succinct, it does not acknowledge the prognostic significance of a pancreatic duct injury. In 1990, the AAST expanded the Organ Injury Scale to include injuries to the pancreas, duodenum and bowel [27]. This five grade scheme (Table IV) acknowledges the significance of more complex injuries to the pancreas, and in particular those injuries affecting the pancreatic duct and the head of the gland. Furthermore, this classification system allowed correlation with other organ injury scales, as well as
Table IV. AAST classification of pancreatic trauma. Grade I II III IV V
Haematoma Laceration Haematoma Laceration Laceration Laceration Laceration
Injury description Minor contusion without ductal injury Superficial laceration without ductal injury Major contusion without ductal injury or tissue loss Major laceration without ductal injury or tissue loss Distal transection or pancreatic parenchymal injury with ductal injury Proximal transection or pancreatic parenchymal injury involving the ampulla Massive disruption of the pancreatic head
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G. C. Oniscu et al.
Table V. Frey and Wardell classification of pancreatic trauma. Grade and location of injury Pancreas Class I (P1) Class II (P2) Class III (P3) Duodenum Class I (D1) Class II (D2) Class III (D3)
Combined Type I Type II Type III Type IV
Injury description
Capsular damage, minor parenchymal damage Partial/complete duct transection in the body/tail Major duct injury involving the head of pancreas or the intrapancreatic common bile duct Contusion, haematoma or partial thickness injury Full thickness duodenal injury Full thickness injury with / 75% circumference injury or injury to the extrahepatic common bile duct P1D1, P2D1, D2P1 D2P2 D3P1 2, P3D1 2 D3P3
integration into more complex scoring systems, such as Injury Severity Score (ISS) or Trauma Score / Injury Severity Score (TRISS), which determine the probability of survival for an individual patient. The frequent association between pancreatic and duodenal trauma and the implications for the definitive management of these associated injuries has been recognized by Frey and Wardell [28], who proposed a complex classification system. They defined degrees of pancreatic trauma and duodenal trauma separately (Table V) and established four types of combined injuries with increasing severity that correlated with poorer outcome. As with liver trauma, CT scanning is the main diagnostic procedure used to identify pancreatic trauma (Figure 2); however, there is evidence that CT is not very accurate in detecting pancreatic duct injuries [25,29]. Given the prognostic value of the ductal injury, endoscopic retrograde pancreatography (ERP) is currently the gold standard procedure for the characterization of the pancreatic duct. Takishima et al. [30] have used this to describe a three class
classification of pancreatic ductal injuries: class 1, radiographically normal duct; class 2a, contrast from branch injuries does not leak outside the pancreatic parenchyma; class 2b / contrast from branch injuries leaks into the retroperitoneal space; class 3: main duct injuries. Takishima correlated the classification scheme with subsequent surgical management and concluded that class 1 and class 2a injuries could be treated nonoperatively with minimal risk of complications, while all other injuries required a laparotomy and at least a drainage procedure. Although most pancreatic injuries are detected intraoperatively, it is important to have an accurate classification, even if this is established at laparotomy, to ensure adequate treatment of the pancreatic trauma and any other associated injury. Conclusion An accurate classification of hepatic and pancreatic injuries is an essential step in the management of trauma patients. A precise grading system must be guided by the mechanism, anatomy and extent of the injuries and should correlate with a treatment strategy and subsequent outcome. The Organ Injury Scale proposed by the AAST fulfils most of these criteria and at present is the universally accepted classification scheme, which allows meaningful comparisons of the literature and guides further development of management protocols.
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Figure 2. CT scan showing pancreatic body and tail trauma with associated splenic artery pseudoaneurysm.
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