COMPLEX HEPATIC INJURIES

COMPLEX AND CHALLENGING PROBLEMS IN TRAUMA SURGERY

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COMPLEX HEPATIC INJURIES H. Leon Pachter, MD, and David V. Feliciano, MD

The overall mortality incurred by civilians sustaining hepatic injuries remains in the vicinity of lo%, as 70% to 90% of all hepatic injuries are, fortunately, minor. Complex hepatic injuries, which account for the remaining 10% to 30% of hepatic trauma, remain formidable challenges even for the most experienced trauma surgeons. Until recently, these complex hepatic injuries were associated with mortality rates often in excess of 50%.", 23, 24, 52 The last decade, however, has witnessed a number of major changes in the way complex hepatic injuries are managed. These changing approaches have been responsible for lowering the mortality of grade I11 and IV hepatic injuries to under Some of the most significant changes have been identified as follows: (1)the influence of CT scanning on the nonoperative management of adult blunt hepatic trauma48;(2) the Pringle maneuver (occlusion of the portal triad), topical hypothermia isolated to the liver only, and hepatorrhaphy with intrahepatic hemostasis achieved by the finger fracture technique of Lin52,54; (3) perihepatic packing and planned reexploration as part of the "damage control" concept whereby surgery must be terminated under circumstances of hemodynamic instability or coag~lopathy~; and (4) the management of juxtahepatic venous injuries with or without various intracaval shunts. The purpose of this article is to give in-depth analysis of each of the aforementioned advances. AMERICAN ASSOCIATION FOR THE SURGERY ORGAN INJURY SCALE

OF TRAUMA

Essential to any discussion of hepatic injuries is a classification system that is universally accepted so that reports emanating from both this country and abroad can be compared in a meaningful manner. In 1989 and 1994, the Organ

From the Department of Surgery, New York University School of Medicine; Trauma and Shock Unit, Bellevue Hospital, New York, New York (HLP); and the Department of Surgery, Emory University School of Medicine; and Department of Surgery, Grady Memorial Hospital, Atlanta, Georgia (DVF)

SURGICAL CLINICS OF NORTH AMERICA VOLUME 76 * NUMBER 4 * AUGUST 1996

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Injury Scaling Committee of the American Association for the Surgery of Trauma (AAST) delineated the most comprehensive hepatic injury classification to date.45,46 The scope of this classification system is unique in its ability to incorporate both preoperative (CT scanning in blunt injuries) and intraoperative assessment of the extent of hepatic injury (Table 1).Since its publication, the AAST classification system has been regarded as the standard by which hepatic injuries are described. PATIENTASSESSMENTINTHEEMERGENCYDEPARTMENT

After the initial resuscitation, the most important decision to be made is whether or not the patient needs operative intervention. Patients who remain hemodynamically unstable after 2 liters of intravenous fluid almost always have ongoing hemorrhage. When other sites of blood loss (pleural cavity, pelvis/ retroperitoneum, two femurs, or external) can be excluded, these patients should be taken to surgery immediately, where intraoperative resuscitation continues as the abdomen is opened and the source of bleeding temporarily controlled by packing and manual compression. On the other hand, patients who have responded to standard forms of resuscitation and in whom hemodynamic stability has been achieved may undergo further testing. A much-neglected concept in the initial management of patients arriving to

Table 1. LIVER INJURY SCALE (1994Revision) Grade* I

II

Hematoma

Subcapsular,
Laceration

Capsular tear, <1 cm parenchymal depth

Hematoma

Subcapsular, 10%-50% surface area; intraparenchymal, <10 cm in diameter 1-3 cm parenchymal depth, <10 cm in length

Laceration 111

Hematoma

Laceration IV

Laceration

V

Laceration Vascular

VI

Injury Description

Vascular

Subcapsular, >50% surface area or expanding; ruptured subcapsular or parenchymal hematoma lntraparenchymal hematoma >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 Juxtahepatic venous injuries; i.e., retrohepatic vena cavdcentral major hepatic veins Hepatic avulsion

ICD-9

AS90

864.01 864.11 864.02 864.12 864.01 864.11 864.03 864.13

2 2 2 2 3

864.04 864.14 864.04 864.14

3 4 5 5

6

*Advance one grade for multiple injuries, up to grade Ill. Modified from Moore EE, Cogbill TH, Jurkovich GS, et al: Organ injury scaling: Spleen and liver (1994 revision). J Trauma 38:323-324,1995; with permission.

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the emergency room with complex hepatic injuries is the prevention of systemic hypothermia. Systemic hypothermia begins in the field where the injured patient in shock develops vasoconstriction. The process carries over into the emergency department (ED) and, if ignored, ultimately into the operating room, where its adverse effects become manifest. All too often, the initial treating physicians are so engrossed in resuscitating an unstable patient that they forget the simple sequence of maneuvers that can aid in preventing this catastrophic complication. Merely covering the patient with heated blankets and the patient’s head with a turban in the ED and infusing warm fluids and blood may be sufficient to limit the extent of hypothermia. Maneuvers to prevent hypothermia should continue in the operating room and include the use of a heating blanket under the patient, covering the patient’s extremities with a Bair Hugger (Augustine Medical, Inc., Eden Prairie, MN), and irrigating the peritoneal cavity with warm solutions.

DIAGNOSTIC TESTS IN THE HEMODYNAMICALLY STABLE PATIENT Diagnostic Peritoneal Lavage The role of diagnostic peritoneal lavage (DPL) in the assessment of patients sustaining blunt abdominal trauma has been markedly diminished by the development of ultrasonography and advanced CT scanners. Although DPL still has an accuracy rate of 98% in detecting intraperitoneal it has the following major drawbacks: (1) it lacks specificity as to which organ system has been injured; (2) it is too sensitive in detecting minute quantities of blood, which may lead to a nontherapeutic laparotomy; and (3) it is inaccurate in detecting retroperitoneal and diaphragmatic injuries. As a result, DPL has been, for the most part, superseded by ultrasonography for unstable patients and CT scanning in stable patients as a diagnostic test of choice when managing blunt abdominal injuries. Yet, DPL continues to play a pivotal role in those situations in which ultrasonography or CT scanning is inappropriate or unavailable and the determination of the presence of intraperitoneal blood must be made rapidly.

Emergency Department Ultrasonography Ultrasonographic evaluation of hemodynamically unstable or stable patients with blunt abdominal injuries in the ED by surgeons is rapidly increasing. Responsible factors include the following: (1) a greater familiarity with the technique; (2) the availability of high-quality compact units; (3) the ability to determine the presence of intraperitoneal blood, usually within 2 minutes; and (4) the relative inexpensiveness of the pr~cedure.~, 35, A recent prospective study examining the results of ED ultrasonography performed by surgeons revealed that the procedure could be carried out with an 81.5% sensitivity and a 99.7% specificity.a As expected, the accuracy of interpretation is directly proportional to increasing experience. As familiarity with this technique increases, more accurate delineations of the anatomy of injury will surely follow. Bedside sonography may very well, in the future, replace CT scanning as the initial diagnostic screening test in stable or unstable patients with blunt abdominal injuries.

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CT Scanning

The single greatest contributing factor allowing for nonoperative management of blunt hepatic injuries has been CT scanning. Many of the initial fears concerning the nonoperative management of blunt hepatic injuries in stable patients have been allayed by the recognition that the CT scan can accurately delineate the anatomy of the injury while providing crucial information regarding the volume of intraperitoneal blood and the status of the retroperitoneal structures and gastrointestinal tract. Further advances in technology have led to the development of faster and more accurate scanners such as the spiral CT. In the past the primary role of CT scanning in the trauma patient was to detect the presence of postoperative intraperitoneal fluid collections or abscesses. At present, the role of CT scanning in the emergency setting is equally important, and, without it, nonoperative management of blunt adult hepatic injuries would not be possible. NONOPERATWE MANAGEMENT OF BLUNT HEPATIC INJURIES IN ADULTS

Until the early 1980s patients sustaining blunt abdominal trauma were treated in one of two ways. Patients with hemodynamic instability or obvious peritoneal signs were immediately taken to the operating room for abdominal exploration. Other patients who were hemodynamically stable and exhibited equivocal abdominal signs or those in whom adequate assessment of the abdomen was not possible owing to neurologic injury, alcoholic intoxication, or drug abuse underwent DPL. If the DPL proved positive, celiotomy was undertaken without delay.26Surgical findings, however, often included relatively minor quantities of intraperitoneal blood as well as insignificant injuries. These findings were especially true for patients sustaining blunt hepatic injuries in whom the rate of nontherapeutic celiotomies based on a positive DPL was noted to be as high as 67%.’O,31, 33, 36, 37, 56 This startling finding, as well as the recognition that the majority of blunt hepatic injuries have already stopped bleeding by the time surgical intervention has taken place,’, 13, 41, M, 63 set the stage for an overall reassessment in the management of blunt hepatic injuries in adults. Nonoperative management of blunt hepatic injuries, an already established practice in 37 seemed to be a logical alternative. Despite the pediatric surgical literat~re,’~, ~, management of adult blunt hepatic documented S U C C ~ S S ~ S56, ~nonoperative injuries was not readily accepted because it was not clear that the lacerated liver in the adult would undergo spontaneous hemostasis and healing.28,57 Also, there was a concern that concomitant enteric injuries could not be excluded with any degree of certainty. The evolution of high-speed CT scanners, for the most part, dispelled these concerns. CT scans have demonstrated that the injured liver is clearly capable of spontaneous hemostasis and subsequent and that enteric injuries were infrequently overlooked.’ Additionally, the ability of the CT scan to quantitate the degree of hernoperitoneum and to provide invaluable information Concerning retroperitoneal structures and the diaphragm, areas poorly assessed by DPL, sets the stage for a greater willingness among surgeons to practice nonoperative management of blunt hepatic injuries in adults. Criteria for Nonoperative Management

Consensus on which inclusion criteria must be met for patients to be considered candidates for nonoperative management is lacking. Those generally

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accepted are as follows: (1) hemodynamic stability; (2) CT scan delineation of the injury; (3) lack of associated enteric or retroperitoneal injuries on CT scan which would necessitate prompt operative intervention; (4) absence of peritoneal signs; and (5) a limited number of hepatic-related transfusions during the period of In the face of hemodynamic stability, the degree of hemoperitoneum and the AAST grade of hepatic injury are less critical factors than was originally assumed. CT scan documentation of either improvement or resolution of the injury, once considered an essential inclusion criterion, seems no longer to be necessary in all but grade IV and V injuries. A recent analysis of 404 patients who were managed nonoperatively after sustaining blunt hepatic injuries revealed that 206 patients (51%)did not undergo follow-up CT scanning. None of these patients experienced untoward effects as a result of not undergoing a ”second” scan.” In patients with major hepatic injuries (grades IV and V), however, repeat CT scanning is essential, as it provides crucial information on the status of the injury. This information aids in the decisions to perform laparotomy and to transfer the patient from the critical care unit, establishes guidelines for discharge planning, and serves as the anatomic basis by which patients are permitted to resume normal or athletic activities. Since 1988, more than 1000 adult patients with blunt hepatic injuries have been managed nonoperatively. In a review of 495 patients from the recent literature, the success rate attained with this form of treatment was 94%. This was accomplished with a mean transfusion rate of 1.9 units; a 6.2%complication rate, of which only 2.8% was hemorrhage related; and a mean hospital length of stay of 13 days. In this review there were no hepatic-related deaths, nor were there any missed enteric injuries.@Similar results were achieved with nonoperative management of 404 blunt hepatic injuries in adults by a multiinstitutional study group. This study documented that 98.5% of the patients managed in this manner avoided surgical intervention while incurring a complication rate of only 5%. Although bleeding continued to be the most common complication, occurring in 14 patients (3.5%), only 3 patients (0.7%) required operative intervention to arrest hemorrhage. Other complications such as perihepatic abscesses and collections of bile (“bilomas”) occurred infrequently (1.5%).The overwhelming majority of these complications resolved spontaneously, and those that did not were easily managed by percutaneous drainage under CT scan guidance. Only one patient required operative intervention after pprcutaneous catheter drainage failed to permanently eradicate an intrahepatic abscess. It was disturbing, however, that there were two hepatic-related deaths (0.5%) and two (0.5%) missed enteric injuries in the study.” AAST Grade of Hepatic Injury and Nonoperative Management The nonoperative management of blunt adult hepatic injuries was initially limited to patients with AAST grades I to 11117,54 or those with a minimal amount of blood detected in the peritoneal cavity by CT scan.zo, 43 Documentation that a growing number of select patients with more extensive injuries (grades IV and V) could be managed nonoperatively continues to grow.6,12,38, 42, 64 Recent reports by Meredith42and Croce et all2 cite that 21% and 38%, respectively, of their blunt grades IV and V hepatic injuries were managed nonoperatively. It should be noted, however, that of the 404 patients reported by Pachter and the multicenter study group, grades IV and V injuries constituted only 14% (n=58). More importantly, 66% of patients requiring operative intervention in this group of

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404 patients were among the group with grades IV and V hepatic injuries.5O This subgroup of patients with the most severe hepatic injuries are initially at greater risk for treatment failure and should be more closely monitored and for longer periods of time in a critical care unit?*,50

Pitfalls of Nonoperative Management

As more adult patients sustaining blunt hepatic injuries are managed nonoperatively, one can expect the complication rate to increase. The major areas of concern are missed enteric injuries, hemorrhage, and subsequent hepatic-related deaths. These complications can be minimized if common pitfalls are recognized and avoided. Missed Intra-abdominal Injuries

The concern about missed enteric injuries is rooted in a 5% incidence noted in most reviews of patients with isolated blunt hepatic injuries7 The hazards of nonoperative management of blunt abdominal injuries were also stressed by Fischer et al,27who noted a 15%incidence of enteric disruption in this patient group. Both of these studies, however, were conducted without benefit of CT scanning. Whether these injuries would have been identified had preoperative CT scanning been performed remains conjectural. If one combines the two single largest reported series of nonoperative management of blunt adult hepatic 50 The missed injuries (899 patients), only 2 enteric injuries were enteric injury rate of 0.2% could not have been achieved without the involvement of a dedicated radiology staff. The importance of the role of an experienced radiologist to ascertain whether an intra-abdominal injury is present on the initial CT scan cannot be overemphasized. In a retrospective series of 36 intestinal injuries, Sherck and OakeP noted that the intestinal injuries were missed on initial CT scan in 10 patients. Further analysis implicated the poor quality of the emergency scans as well as the lack of an experienced radiologist doing the initial review of the CT scan as being predominantly responsible for the missed injuries. Confirming this observation, Matsubara et a140 noted that the accuracy of CT scanning increased from 79% to 88% when more experienced radiologists reviewed the initial films. Nevertheless, an increasing number of reports detailing missed intra-abdominal injuries will most likely be forthcoming as more patients with blunt hepatic injuries are managed nonoperatively. In a recent prospective series by Croce et all2 of 112 adult patients with blunt hepatic injuries managed nonoperatively, 4 of 12 failures (33%) were due to missed intra-abdominal injuries (2 pancreatic, 1 renal, 1 duodenal). Of interest, no untoward effects occurred in Croce and associates’1zseries or in the multicenter study reported by Pachter et a1.5O This presumably reflects the constant reassessment of injured patients by the surgical staff and prompt operative intervention once the diagnosis was made. Despite an accuracy rate of 97% to 99% in detecting associated intra-abdominal injuries, the CT scan is not infallible. Also, it does not serve as a substitute for constant re-examination, preferably by the same set of examiners, of the patient whose abdominal examination remains equivocal in spite of a CT scan.

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Hemorrhage

Hemorrhage from the injured liver severe enough to manifest itself by hemodynamic instability rarely occurs in the immediate observation period. More commonly, a slowly dropping hematocrit causing a continuing need for transfusions, especially in patients with multiple other associated injuries, leads to the difficult dilemma of whether or not the liver lesion is the source of hemorrhage. Under these circumstances a repeat CT scan should be undertaken without delay. If the hepatic lesion is unchanged, it is unlikely that the transfusion is hepatic related. If, on the other hand, the hepatic lesion has become more extensive, along with an increase in perihepatic or intraperitoneal blood, then additional treatment is required. The hemodynamically stable patient should undergo angiography for the express purpose of embolizing the bleeding vessel. Hemodynamic instability is indicative of significant ongoing hepatic hemorrhage and mandates immediate operative intervention. Similarly, “pooling of contrast materiaP4 or the presence of contrast material within the injury site noted on the initial CT scan is indicative of active bleeding. Preparations should promptly be made for operative intervention regardless of CT scan grade of injury or hemodynamic stability, as rapid deterioration in the patient’s hemodynamic status can suddenly occur. With an operating room on standby, the hemodynamically stable patient may be taken to the angiography suite where angioembolization is attempted by an experienced interventional radiologist. Angioembolization resulting in the arrest of ongoing hemorrhage from the offending vessel can usually be accomplished, obviating operative intervention and allowing for the continued nonoperative management of the patient. Failure to successfully embolize the bleeding vessel mandates immediate transfer of the patient to the operating suite for surgical control of the lacerated vessel. With regard to hemorrhage, there are three major errors to avoid. First, it is an error to attribute the bleeding to a non-hepatic-related cause without CT verification that the hemorrhage is not arising from the injured liver and to continue to transfuse based on that assumption. Second, it is an error to accept the concept that excessive hepatic-related transfusions are preferable to operative intervention in the hope that bleeding from the liver will eventually stop and surgical intervention can therefore be avoided. Finally, it is an error to underestimate the potential risks when the presence of “pooling of contrast material” is noted on the initial scan in a hemodynamically stable patient, especially when the grade of injury is I11 or less. Unnecessary hepatic-related transfusions are unwarranted for many reasons, not the least of which is that it suggests ongoing bleeding, which can result in sudden hemodynamic instability. Likewise, the risks of contracting hepatitis and the human immunodeficiency virus increase with each unit transfused. A recent report cites that despite extensive pretransfusion screening, the risk of contracting hepatitis C can be as high as 0.23% per unit of blood t r a n s f ~ s e dDespite .~~ the well-documented 1% to 1.5%incidence of transfusiontwo reports in the literature describe patients receiving 1030 related rn~rtality?~ and 1664units during the period of nonoperative management. Large series of patients sustaining blunt hepatic injuries and managed nonoperatively have shown that excellent results can be achieved with minimal blood transfusions.’2,48 Most striking, however, were the recent data provided by Pachter and the Western Trauma Association multicenter study In the 404 patients with blunt hepatic injuries managed nonoperatively, 89% (n = 361) received no blood.

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Of those patients requiring transfusion, a mean rate of only 0.42 unit per patient was noted. Previous contentions that hemorrhagic complications accompanying the nonoperative management of adult blunt hepatic injuries would be inordinately high were exaggerated. Additionally, although hepatic-related mortality as a result of failure of nonoperative management does exist, its rate of occurrence appears to be under o.5%.50 Although conjectural, had patients with more advanced blunt hepatic injuries been operated on and standard surgical techniques used to arrest bleeding instead of being managed nonoperatively, a higher mortality would most likely have resulted. Bile Collections and Abscesses

Intrahepatic and perihepatic collections of bile ("bilomas") are noted to occur at rates that vary from 0.5?'0'~to 20Y0'~with the nonoperative management of blunt hepatic injuries. The 20% incidence of bilomas in 100 adult patients reported by Croce et all2merits qualification, as the diagnosis was determined, for the most part, by nuclear scanning techniques. Only one of these 20 patients (5%) required percutaneous drainage, for a true complication rate of 1%.The other 19 bilomas resolved spontaneously. When CT scanning was used to make the diagnosis, Pachter et a150 noted that only 2 (0.5%) significant bile collections were seen in a series of 404 patients. Both of these bile collections were successfully drained percutaneously. Additionally, Pachter et a150noted that of the three patients who developed perihepatic or intrahepatic abscesses in the same study group, two were managed by percutaneous drainage and only one required operative intervention. Biliary Ductal Disruption and Subsequent Stricture Formation

The long-term effect of spontaneous healing of significant hepatic parenchymal lesions on the eventual development of biliary ductal stenosis is unknown. Sugimoto et aP6 recently reported that the incidence of biliary ductal disruption in patients who sustained severe parenchymal destruction may be higher than previously appreciated. Of 28 patients with advanced hepatic parenchymal lesions in their series, Sugimoto et ale used endoscopic retrograde cholangiopancreatography (ERCP) to demonstrate that 21.4% (n = 6) sustained intrahepatic ductal injuries. Of these 6 patients, only 1, however, required surgical intervention, 3 others required percutaneous drainage of enlarging bilomas, and the remaining 2 resolved spontaneously. To the best of our knowledge, only one case report is available in the literature documenting biliary ductal stricture 3 months after a patient with a grade I11 to IV injury was managed nonoperati~ely.~O The authors recently treated a patient sustaining a blunt torso trauma who presented 48 hours after injury complaining of epigastric pain and fever. On admission his temperature was 102°C and his white blood cell count was 22,000. An abdominal CT scan revealed a complex injury of the liver contained within Glisson's capsule. Because the patient was febrile, percutaneous drainage of the lesion was undertaken and yielded 300 mL of old blood with subsequent collapse of the cavity. Subsequent sinography, however, revealed free communication with the left hepatic duct and the common bile duct. A biliary fistula ensued, but ceased to drain within 10 days. An ERCP performed on postdrainage day 14 failed to reveal any extravasation of contrast from the end of the left hepatic duct, and the percutaneous catheter was accordingly removed. Whether or not this patient will go on to stricture formation is not known,

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but constant follow-up remains essential. What is clear at the moment is that intrahepatic disruption of a main hepatic duct after blunt injury to the liver in a hemodynamically stable patient is a rare event. When biliary ductal disruption does occur, the secondary and tertiary radicals are most often affected. The spillage of bile under these circumstances is usually self-limited and, at worse, the biloma that forms usually resolves. Nevertheless, long-term follow-up is required to see if the incidence of intrahepatic biliary strictures remains as low as it has been to date. Resumption of Normal Activities

Confusion seems to surround the timing of return to normal activities after the nonoperative management of blunt hepatic injuries. There continues to be concern that vigorous activities, if undertaken too soon after injury, may precipitate hemorrhage. As a result, an arbitrary time period of limited activities, usually 3 to 6 months, has been chosen. There is, however, no scientific evidence to support this policy. Although the natural history of the patterns of healing of blunt hepatic injuries was documented as early as 1983 by Karp et aP7(complete restoration of liver homogeneity at 3 to 4 months), few data exist with regard to hepatic wound bursting strength after operative intervention or nonoperative management. In experimental models, Dulchavsky et all6 were able to demonstrate that at 3 weeks after injury the hepatic bursting strength of the injured liver was equivalent to and at times exceeded the wound bursting strength of normal hepatic parenchyma. Additionally, when three different methods of treating experimentally induced hepatic injuries (hepatic repair alone, hepatic repair and an omental pack, and observational treatment) were compared, Dulchavsky et a1 noted that repair by secondary intention resulted in wound bursting strengths that equaled or surpassed those of all other forms of treatment studied. The conclusion of these scientific experiments suggests that when patients with blunt hepatic injuries are managed nonoperatively, healing by secondary intention occurs as a result of a proliferative fibrosis encompassing both the hepatic parenchyma and Glisson’s capsule.16,61 In patients managed nonoperatively, if one can extrapolate experimental data, hepatic wound bursting strength should be comparable to and may even exceed normal hepatic parenchymal wound bursting strength at 6 weeks after injury as a result of the aforementioned proliferative fibrotic process. To extend the limit of return to normal activities beyond 8 weeks (2-week additional safety margin) seems unwarranted and cannot be substantiated scientifically. Future of Nonoperative Management

The current extraordinary success rate of the nonoperative approach in the management of adult blunt hepatic injuries has firmly established this mode of therapy as the preferred method. The number of patients sustaining blunt injuries who can be treated by this approach is currently unknown. Initial estimates that only 15% to 20% with blunt hepatic injuries could be managed nonoperatively proved inaccurate and grossly underestimated the potential for this approach. Three recent reports cite that the nonoperative management of blunt hepatic injuries constituted anywhere from 50% to 82%12,42, of all blunt adult hepatic injuries managed within the last few years. Of the 404 patients reported by the multicenter study group, nonoperative management of blunt

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hepatic injuries varied from a low of 20% to a high of To%, with a mean rate of 47?'0.~'As experience with this form of therapy grows, more surgeons will be willing to manage a greater majority of their patients with blunt hepatic injury nonoperatively. Currently, at least 50% of patients with blunt hepatic injuries are managed nonoperatively, and this figure will likely approach 80% in the not too distant future. NONOPERATIVE MANAGEMENT OF PENETRATING HEPATIC INJURIES IN ADULTS

It is of interest that most civilian gunshot wounds of the liver result in grade I1 or I11 injuries. These are much smaller than many of the grade I11 to V injuries that are currently being treated nonoperatively after blunt hepatic trauma. For this reason, Renz and F e l i ~ i a n oconducted ~~ a prospective study in which stable and relatively asymptomatic patients with gunshot wounds to the right thoracoabdomen presumably involving the liver would be treated nonoperatively. With serial physical examinations and CT scans, 13 consecutive carefully selected patients (7 with documented hepatic lacerations on CT scan) were successfully managed without operation. A subsequent report from the same authors documented the importance of avoiding nonoperative management in stable patients with high CT density (> 100 Hounsfield units) collections of intrahepatic hematoma, as ongoing hemorrhage was likely to be OPERATIVE MANAGEMENT OF COMPLEX HEPATIC INJURIES

The optimal incision for exploring a patient with a complex hepatic injury is a midline incision, which affords wide access to all peritoneal and retroperitoneal structures. The midline incision, in combination with the use of a Rochard retractor, readily exposes all anatomic aspects of the liver, and a thoracic extension of the original incision for better exposure is seldom required. Once the abdomen is opened, all efforts should initially be directed toward intraoperative resuscitation, with correction of the potentially lethal effects of hypovolemia and lactic acidosis. This is best accomplished by the simple maneuver of compressing the hepatic injury while hemodynamic and metabolic derangements are corrected by the anesthesia team (Fig. 1).The pitfall to avoid is to surgically embark on a course to arrest bleeding without the benefit of appropriate intraoperative resuscitation. Failure to adhere to this rather simple principle, more often than not, results in a cascade of events leading to systemic hypothermia and coagulopathy." Once the intraoperative resuscitation is complete, a more orderly assessment of the injury can be undertaken. Complex injuries (grades 111 and IV) are best managed by the following five critical steps: (1)portal triad occlusion; (2) finger fracture of the hepatic parenchyma (hepatotomy) to expose lacerated blood vessels and bile ducts for direct ligation or repair; (3) dkbridement of nonviable hepatic parenchyma; (4) insertion of a viable omental pedicle into the injury site; and (5) closed suction drainage for grades I11 to IV hepatic injuries. Strict adherence to these maneuvers, coupled with the concept of "damage control" and the appropriate use of perihepatic packing, resulted in an overall mortality of 12% in 128 consecutive patients sustaining AAST grades I11 to V hepatic injuries in one series.54

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Figure 1. The surgeon applies manual compression to the complex hepatic injury as the anesthesiologist performs intraoperative resuscitation. (Copyright 0 1987, Baylor College of Medicine, Houston, TX; courtesy of David V. Feliciano, MD.)

Pringle Maneuver (Portal Trial Otclusion)

Complex hepatic injuries usually continue to bleed, necessitating crossclamping of the portal triad (Pringle maneuver), most often performed with an atraumatic vascular clamp.49,51 The fear of prolonged continuous clamping of the portal triad beyond 15 to 20 minutes is unwarranted based on data provided by experiences in both trauma and elective hepatic surgery?, 15*34, 51* In a series of 113 surviving patients with complex hepatic injuries, Pachter and associates” reported that 81 patients (72%) required portal triad occlusion. The range of occlusion times varied from 10 to 75 minutes, with a mean occlusion time for the entire group of 32 minutes. %e mean occlusion time, however, increased to 46 minutes when patients sustaining grade V injuries were considered. Under controlled and elective conditions, the liver has been noted recently to tolerate normothermic ischemia times of up to 90 minutes15and mean ischemia times of 67.5 minutesM Uncertainty about the liver’s ability to tolerate normothermic ischemia during periods when hypotension and hypoperfusion of hepatic parenchymal cells have already taken place has led Pachter et a154to seek methods of providing hepatocyte protection prior to portal triad occlusion. Until recently, Pachter et a1- employed both topical hypothermia (cooling the liver to 30 to 32°C) and a single intravenous bolus of steroids (3040 mg/kg of methylprednisolone succinate) to safely extend normothermic ischemia time to the liver. Fundamentally, regional hypothermia is believed to slow cellular metabolism and lower the hepatocyte threshold for energy requirements?, 29 The mechanism by which steroids work is less clear, but their effect is believed to be related to the ability to stabilize lysosomal and cellular rnembranes.l4,25 Although neither of these methods was proven to be effective in randomized prospective studies, Pachter et al” nevertheless reported only 11 instances of perihepatic abscesses (8.6%) and no instances of hepatic necrosis with their combined empiric use in 128 consecutive patients sustaining complex hepatic injuries.

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The lack of prospective randomized trials regarding either topical hypothermia or the use of steroids in prolonging warm ischemia time to the liver led to a critical evaluation of their protective efficacy in experimental studies. The experimental design was directed toward examining high-energy phosphates (ATP) extracted from the hepatic parenchyma and quantified by high-pressure liquid chromatography during gradual periods of hepatic ischemia. It was postulated that in the events culminating in cell death during anoxia, the gradual decline in percentage of ATP resulting from a diminished rate of oxidative phosphorylation plays a pivotal role. A decrease in the measurable amount of ATP from within the hepatic tissues during varying periods of hepatic ischemia should accurately reflect the viability rate of hepatic parenchymal cells in vivo. Studies performed on 40 New Zealand white rabbits revealed that topical hypothermia alone (30°C) conferred a statistically significant protective effect on ATP levels within the hepatic parenchyma at 15 and 30 minutes of ischemia (RO.01). Although the topical hypothermia resulted in the highest percentage of remaining ATP at 60 minutes, this figure was not statistically significant. Intravenous steroids (methylprednisolone succinate, 30 mg/kg) given prior to portal triad occlusion were not found to have a protective effect on ATP levels at any time point (R0.05). When topical hypothermia was combined with intravenous steroids, a statistically protective effect on ATP levels up to 30 minutes was also noted (KO.01). Compared with topical hypothermia alone, the protective effect of the combination of topical hypothermia and steroids was, however, less pronounced.18This study was limited in that the high-energy phosphate nucleotide ATP was chosen as the sole marker of cellular energy change to reflect hepatocyte protection. Steroids may affect hepatocyte survival through alternative pathways independent of and unrelated to changes in cellular energy. Further studies at the cellular level are clearly needed to elucidate mechanisms that may contribute to a better understanding of how best to protect the liver during extended periods of ischemia. The recent experimental data, although examining only a single aspect reflective of hepatocyte viability, seem to confirm clinical observations that topical hypothermia can significantly contribute to extending hepatic ischemia time.18 Based on the above studies, high-dose steroids cannot currently be justified as an acceptable method to extend hepatic ischemia. Experimental studies correlated with randomized prospective clinical trials are required to assess what role, if any, steroids play in providing hepatocyte protection during occlusion of the portal triad. lntrahepatic Hemostasis-Hepatorrhaphy by the Finger Fracture Technique

There exists an almost 20-year literature attesting to the safety and efficacy of hepatotomy via the finger fracture technique of Lin to achieve intrahepatic hemostasis when dealing with complex hepatic injuries.", 24, 51-54 This technique, coupled with portal triad occlusion (Pringle is especially suited for grades I11 to V injuries, as lacerated blood vessels and bile ducts are rapidly exposed for either ligation or repair under direct vision (Fig. 2). The use of this technique has been tempered by the fear that incising normal hepatic tissue might exacerbate bleeding en route to gaining access to the major source of hemorrhage. In Pachter's series of 128 consecutive complex hepatic injuries, 99% were managed by finger fracturing normal hepatic parenchyma in order to achieve

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Figure 2. With a Pringle maneuver in place, hepatotomy allows for selective vascular ligation of disrupted parenchymal vessels and biliary ducts. (Copyright 0 1980, Baylor College of Medicine, Houston, TX; courtesy of David V. Feliciano, MD.)

intrahepatic hemostasis. If one excludes patients with juxtahepatic venous injuries involving the retrohepatic cava or hepatic veins (grade V), the finger fracture technique was successful in 93.5%of 107 patients with AAST grades I11 and IV injury whose mean injury severity score was 35. This success rate was achieved with a minimal cumulative morbidity of 15%. There were two instances (1.9%)of postoperative bleeding, eight (7.5%)patients developed perihepatic or intrahepatic abscesses, and six (5.6%)additional patients developed biliary fistulas. The latter all resolved spontaneously, whereas both patients with postoperative bleeding required reoperation, as did three of the eight patients with intraabdominal sepsis.54 The gradual acceptance of the finger fracture technique to expose actively bleeding vessels deep within the hepatic parenchyma” is evidenced by its 43% use in nearly 3000 cumulated instances of hepatic trauma?, The increased use of the finger fracture technique in complex hepatic injuries has been accompanied by success rates comparable to those reported by Pachter et a1.- In a series of 121 complex injuries, BeaP reported that hepatotomy to achieve intrahepatic hemostasis was used in 45 of the group, with a success rate of 87%. Viable Omental Pack

Once bleeding has been arrested, perihepatic and intrahepatic sepsis represent the most common long-term complications. Although neither can be eliminated entirely, the incidence can be decreased by debriding nonviable hepatic tissue after hemostasis has been achieved. The only acceptable criterion of viability is healthy bleeding hepatic parenchyma. With the debridement process complete, it has been the authors’ preference to mobilize a viable pedicle of

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omentum based on the blood supply provided by either of the gastroepiploic vessels for insertion within the injury site (Fig. 3). By this means a large dead space is filled with viable tissue and, at the same time, the bulk of the omentum is extremely efficient in tamponading minor venous oozing, which invariably emanates from the raw hepatic parenchymal bed.", 51 Fabian et al,I9on the other hand, have used omental packing in 60% of complex hepatic injuries requiring advanced techniques to control hepatic hemorrhage. Although there are concerns that an omental pedicle might trap blood and bile at the injury site and set the stage for the subsequent development of either an abscess or a biloma, Pachter et al" and Fabian et all9 report postoperative abscess rates of only 8.6% and 8%' respectively, with its use. Resectional Debridement with Selective Vascular LigationlResection

When friable or partially devascularized hepatic tissue is found on the edge of a lobe or in a hepatic laceration, resectional dbbridement is performed instead of a formal hepatic resection. By use of a finger fracture technique or electrocautery just outside the injured area, selective clipping of intact biliary ducts and vessels before they enter the area to be dkbrided is perf0rmed.2~In the patient with a coagulopathy, "rapid" resectional dkbridement is performed by applying large liver clamps or aortic vascular clamps to either side of the injured area to be dkbrided. Once dkbridement between the clamps is completed, large horizontal mattress sutures are placed behind the clamps to attain hemostasis. A viable omental pedicle may then be inserted into the area that was dkbrided. Extensive lobar dkbridement or anatomic segmentectomy or lobectomy is indicated when there is a burst injury of a segment or lobe, when it is the only

Figure 3. A viable omental pedicle is placed into large hepatic lacerations or hepatotomy sites once reasonable parenchymal hemostasis has been attained. (Copyright 0 1985, Baylor College of Medicine, Houston, TX; courtesy of David V. Feliciano, MD.)

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Figure 4. Although anatomic lobectomy is indicated rarely, left lateral segmentectomy is appropriate for grade 111 to IV lacerations at the falciform ligament.

technique that will control mechanical hemorrhage, or when the insertion of perihepatic packs fails to control mechanical hemorrhage (Fig. 4). Major resections have been used in only 2% to 4% of all patients undergoing operative management of hepatic injuries in recent After application of a Pringle maneuver and consideration of extending the midline incision into a median sternotomy, a lobectomy is performed to either side of the middle hepatic vein using the finger fracture technique or electrocautery. Preliminary dissection of hilar structures to the lobe to be resected is not performed with trauma lobectomy.

Perihepatic Packing Perihepatic packing is necessary in approximately 4% to 5% of all patients undergoing operative management of hepatic injuries.z2, 24 The indications are the onset of an intraoperative coagulopathy, failure of other maneuvers to control hemorrhage when resection is precluded by ”metabolic” failure, the presence of a subcapsular hematoma, or the presence of bilobar injuries. Folded dry laparotomy pads are used to exert direct pressure on the injured lobe without causing compression of the retrohepatic vena cava. Should fresh suture lines be the source of oozing, the insertion of a small piece of nonadherent plastic drape between the suture line and the dry packs is appropriate (Fig. 5). Perihepatic packs are most commonly removed at a reoperation 48 to 72 hours after the first operation. This is usually the time when the patient’s hypothermia, acidosis, and coagulopathy have been corrected, and there is no obvious cardiovascular, respiratory, or renal contraindication to a reoperation. Despite the fact that perihepatic packing is used in desperate circumstances in many patients with complex hepatic injuries, the mean survival in eight collected series including 145 patients from 1976 to 1986 was 72%.

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Figure 5. A and B, Perihepatic packing with dry laparotomy pads is placed over a plastic drape when there are parenchymal su- A ture lines that may become adherent to the packs. (Copyright 0 1985, Baylor College of Medicine, Houston, TX; courtesy of David V. Feliciano, MD.)

Other Techniques Absorbable mesh wrapping of burst hepatic injuries containing viable parenchymal fragments is now done in many By proper circumferential placement of the mesh around the injured lobe, a tamponading effect results. Also, in contrast to the insertion of perihepatic packs, there is no need for removal of absorbable mesh. Intrahepatic balloon catheter tamponade is another innovative technique that allows for control of deep parenchymal hemorrhage in stab or missile Successful positioning of the balloon at the site of hemorrhage eliminates the need for extensive hepatotomy or lobar resection in selected patients. Atriocaval Shunt for Grade V Injuries An extensive discussion of the use of the atriocaval shunt is beyond the scope of this article. In general, dark venous bleeding below an injured lobe which cannot be controlled by the insertion of perihepatic packs2is usually best treated by the insertion of a shunt. This is particularly true if the surgeon has little experience with direct retrohepatic or transparenchymal approaches to the injured inferior vena cava.8 With pressure on the liver to compress the retrohepatic vena cava secondarily, the midline abdominal incision is extended into a median sternotomy. After placement of umbilical tape tourniquets around the intrapericardial inferior vena cava and the intra-abdominal suprarenal infrahepatic cava, a 2-0 silk purse-string suture is placed in the right atrial appendage above a Satinsky clamp. The No. 36 chest tube shunt is prepared by cutting an extra hole approximately 20 cm from the most proximal side hole and placing an occlusion clamp at the open end. This chest tube shunt is inserted through the pursestring suture and placed so that all holes in the shunt are outside of the tightened umbilical tape tourniquets (Fig. 6). With use of a No. 8 endotracheal tube as the shunt, the distal balloon replaces the intra-abdominal umbilical tape.

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Diversion of caval return from the lower half of the body and both kidneys into the shunt results in a moderate to significant decrease in bleeding from the caval perforation. The improved exposure that results led to a survival rate of approximately 33% in one series of penetrating wounds to the retrohepatic vena cava.8

Drainage Controversy continues to surround the issue of whether routine drainage of hepatic injuries is necessary. What has become patently clear is that "open" drainage results in the highest incidence of postoperative abscess formation, whereas closed suction drainage is superior to both open drainage and no drainage.I9The scientific support for this conclusion is based on a randomized prospective study by Fabian et al,I9 which documented that closed suction drainage resulted in a postoperative abscess rate of 3.5%when compared with open drainage (13%) or no drainage (6.7%). A reasonable approach is that drainage should be omitted for grade I and I1 injuries. Grade I11 to V injuries that have caused severe parenchymal disruption and the laceration of intraparenchymal vessels and bile ducts are best served by closed suction drainage. Confirmation for this approach is found in at least three large series in which both abscess rate and biliary fistula rate of less than 10% were recorded when closed suction drainage for complex hepatic injuries was used.", 19,

A

Figure 6. A and B, A No. 36 chest tube with an extra hole cut at the level of the right atrium is a readily available atriocaval shunt. (Copyright 0 1987, Baylor College of Medicine, Houston,TX; courtesy of David V. Feliciano, MD.)

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nonoperative management in adults with blunt abdominal injury. J Trauma 28:1445, 1988 28. Flint L, Mays ET, Aaron WS, et al: Selectivity in the management of hepatic trauma. Ann Surg 185:613, 1977 29. Goodall GW, Hyndman WWB, Gurd F N Studies on hypothermia in abdominal surgery. Arch Surg 75:1011, 1957 30. Halme L, Orko R, Tierala E, et a1 Late biliary stenosis after conservative management of traumatic liver rupture: Case report. J Trauma 36740, 1994 31. Hammond JC, Canal DF, Broadie T A Nonoperative management of adult blunt hepatic trauma in a municipal trauma center. Am Surg 58:551, 1992 32. Hiatt JR, Harrier HD, Koenig BV, et al: Nonoperative management of major blunt liver trauma with hernoperitoneum. Arch Surg 125:101,1990 33. Holland MJ, Little JM: Nonoperative management of blunt liver injuries. Br J Surg 78:968, 1994 34. Huguet C, Gavelli A Hepatic resection with ischemia of the liver exceeding one hour. J Am Coll Surg 178454,1994 35. Jehle D, Guarino J, Karamanoukian H Emergency department ultrasound in the evaluation of blunt abdominal trauma. Am J Emerg Med 11:342,1993 36. Jones S, Walsh JW, Maul1 KI: Diagnostic imaging in blunt trauma of the abdomen. Surg Gynecol Obstet 157389, 1983 37. Karp MP, Cooney DR, Pros GA, et al: The nonoperative management of pediatric hepatic trauma. J Pediatr Surg 18:512,1983 38. Knudson MM, Lim RC, Oakes DD, et al: Nonoperative management of blunt liver injuries: The need for continued surveillance. J Trauma 301454, 1990 39. Luna GK, Dellinger EP: Nonoperative observation therapy for splenic injuries. A safe therapeutic option? Am J Surg 153:462, 1987 40. Matsubara TK, Fong HMT, Bums C M Computed tomography of the abdomen (CTA) in the management of blunt abdominal trauma. J Trauma 30:410, 1990 41. Meredith JW,Ditesheim JA, Stonehouse S, et al: Computed tomography and diagnostic peritoneal lavage-complementary roles in blunt trauma. Am Surg 5 8 4 , 1992 42. Meredith JW,Young JS, Bowling J, et al: Nonoperative management of blunt hepatic trauma: The exception or the rule. J Trauma 36:529, 1994 43. Meyer AA, Crass RA, Lim RL Jr, et al: Selective nonoperative management of blunt liver injury using computed tomography. Arch Surg 120:550,1985 44. Moore EE: Critical decisions in the management of hepatic trauma. Am J Surg 145712, 1984 45. Moore EE, Cogbill TH, Jurkovich GJ, et al: Organ injury scaling: Spleen and liver (1994 revision). J Trauma 38:323, 1995 liver, and 46. Moore EE, Shackford SR, Pachter HL, et al: Organ injury scaling-pleen, kidney. J Trauma 29:1664, 1989 47. Morris JA Jr, Wilcox TR, Reed GW, et al: Safety of the blood supply: Surrogate testing and transmission of hepatitis C in patients after massive blood transfusion. AM Surg 219:517, 1994 48. Pachter HL, Hofstetter SR The current status of nonoperative management of adult blunt hepatic injuries. Am J Surg 169:442, 1995 49. Pachter HL, Hofstetter SR, Liang HG: Liver and biliary tract trauma. In Feliciano DV, Moore EE, Mattox KL (eds): Trauma, ed 3. Stamford, CT, Appleton & Lange, 1996, p 487 50. Pachter HL, Knudson MM, Esrig B, et al: The status of nonoperative management of blunt hepatic injuries in 1995: A multicenter experience with 404 patients. J Trauma 40~31-38, 1996 51. Pachter HL, Spencer FC: Recent concepts in the treatment of hepatic trauma. Ann Surg 190:423, 1979 52. Pachter HL, Spencer FC, Hofstetter SR Experience with the finger fracture technique to achieve intra-hepatic hemostasis in 75 patients with severe injuries to the liver. Ann Surg 197771, 1983 53. Pachter HL, Spencer FC, Hofstetter SR The management of juxtahepatic venous

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