Hepatic trauma;  Liver trauma

Hepatic and biliary injuries can occur from any form of trauma including blunt and penetrating mechanisms. They occur when these structures are physically disrupted, resulting in parenchymal contusions, hematomas, or lacerations. Injuries to these organs most commonly result in direct hemorrhage or disruptions of the normal production and flow of bile.

Liver injuries occur in 5 % of patients with blunt trauma to the abdomen (Malhotra et al. 2000), and most of these injuries can be managed without operation. There is a high rate of concomitant injuries, and the overall mortality rate among these patients ranges from 10 % to 15 % (Malhotra et al. 2000; Richardson et al. 2000). Of these patients, one-quarter of the deaths are early, directly resulting from hepatic hemorrhage. Therefore, optimal management of hepatic trauma is based on careful selection of nonoperative versus operative management as well as prompt operative or interventional management to effect rapid control of hemorrhage.

The severity of liver injury is graded by the Organ Injury Scale. Except for the highest grades of liver injury, nonoperative management is the mainstay of therapy for patients who are hemodynamically stable and have no peritoneal signs or other indication for operative intervention. The failure rate of nonoperative management increases with liver injury grade. The overall success rate of nonoperative management is high because in most series, the majority of liver injuries are lower grade. For higher-grade injuries, nonoperative management should be considered a “trial,” in order to encourage a prompt change to operative or interventional management when appropriate.

Most hemodynamically stable blunt trauma patients undergo computed tomography (CT), which has high accuracy in diagnosis of liver injury. CT findings of hepatic injury include liver parenchymal hypoperfusion, subcapsular hematoma, intravenous contrast extravasation (“blush”), and intrahepatic pseudoaneurysms. Hemoperitoneum may also be present. The indications for hepatic angiography and embolization remain controversial. In many centers, hepatic angiography and embolization remains a primary therapy for patients who are hemodynamically stable with IV contrast extravasation on CT (Misselbeck et al. 2009). Other centers may base the decision on a combination of liver injury grade and CT findings.

Patients with liver injury and signs of shock that are refractory to resuscitation should undergo emergency laparotomy to control hemorrhage. Exploration should be preceded (but not delayed) by large-bore intravenous access and mobilization of resuscitative resources such as a massive transfusion strategy with near-equal replacement of blood cells, plasma products, and platelets. Tranexamic acid (TXA) should be considered in hemodynamically unstable patients with suspected blood loss and transfusion requirements. Liver anatomy can be highly variable (Peitzman and Marsh 2012). The mobilization of additional experienced surgeons is encouraged, as the operative management of severe liver injuries requires judgment, meticulous exposure, and knowledge of hepatic anatomy.

The first step of controlling liver hemorrhage is reducing and compressing the fractured area. This is achieved with minimal (if any) formal mobilization. The surgeon should use two hands to restore the normal positioning of the injured liver, thereby apposing injured liver surfaces. This is buttressed with firm packing of dry laparotomy sponges. Pressure must be enough to arrest venous bleeding but not so great as to compress the inferior vena cava and prevent adequate cardiac preload (Peitzman and Marsh 2012). If bleeding persists despite adequate packing, then the surgeon must control vascular inflow to the liver using the Pringle maneuver (Kozar et al. 2011). The surgeon should initially encircle the porta hepatis with the thumb and forefinger (Pringle 1908). The pars flaccida of the hepatogastric ligament is divided, and the porta hepatis is occluded with an atraumatic clamp, vessel loop, or Rummel tourniquet.

Bleeding that stops with application of a Pringle maneuver is highly suggestive of a hepatic arterial or portal venous injuries. The wound should be explored and bleeding sources controlled with direct repair or ligation. Techniques such as finger fracture or linear stapling can be used to extend the injury. However, this approach should only be used to the extent of hemorrhage control. For hemorrhage that is controlled with packing, anatomic or non-anatomic resection is typically not indicated at index operation. Application of the Pringle maneuver should be restricted to short intervals if possible to minimize hepatic ischemic time. However, the optimal time of portal triad occlusion remains unknown, particularly among bleeding patients with liver injuries. As such, rapid identification and control of bleeding is paramount.

Bleeding that continues despite portal triad occlusion suggests hepatic venous injury. Several techniques to control these injuries have been described. Direct repair necessitates exposure of the injury. This is achieved by division of the falciform ligament to the suprahepatic inferior vena cava. The surgeon should then dissect the diaphragmatic attachments of the left or right hemiliver based on the suspected source of hemorrhage. The left hepatic vein is exposed by first dividing the gastrohepatic ligament. The left lateral segment is then retracted inferiorly, and the left triangular ligament is divided with electrocautery or scissors. This allows an assistant to pull the left lobe medially, dropping the gastroesophageal junction down, elevating the caudate lobe, and exposing the confluence of the IVC and left hepatic vein. Much of this venous confluence will be intrahepatic.

If bleeding is suspected from the right or middle hepatic veins, exposure should occur from the right side. The right hemiliver is retracted inferiorly, and the right triangular ligament is incised at the most lateral aspect. This dissection is carried medially, dividing the anterior and posterior leaflets of the coronary ligaments. The liver is then elevated anterior and toward the patient’s left side, exposing the right kidney and adrenal gland. These structures are dropped posteriorly. At this point the surgeon must take great care to avoid injury to the short hepatic veins that drain directly from the liver into the IVC.

Intraparenchymal hepatic venous injuries that are not accessible with liver mobilization and exposure of the hepatic veins are particularly challenging. Atriocaval shunting of the retrohepatic IVC is well described, but it is rarely employed in clinical practice. Similarly, venovenous bypass in the setting of total hepatic vascular occlusion has been described but in practice is logistically challenging, and data regarding efficacy and outcomes in trauma is lacking. In practice, the most effective operative management is damage control extensive perihepatic packing to restore normal anatomy supplemented with immediate postoperative angioembolization. The management of complex hepatic injuries is likely to evolve as hybrid operating rooms and endovascular techniques are incorporated into the trauma surgery armamentarium.

Damage control surgery remains the technique of choice for trauma patients with exsanguinating abdominal injuries (Rotondo et al. 1993). Therefore injury severity must be recognized early, and efforts should be made to truncate the operation when bleeding is controlled and contamination is minimized. The optimal timing of repeat laparotomy is unknown, but the patient should be resuscitated such that hypothermia, coagulopathy, and acidosis have all been reversed (Kozar et al. 2011). At such time, all packs should be gently removed, and tissue viability should be assessed. For nonviable hepatic tissue, non-anatomic resection using finger fracture and linear stapler techniques is associated with improved outcomes (Polanco et al. 2008; Kozar et al. 2011). Endo GIA staplers are oftentimes helpful when anatomy makes utilization of standard staplers difficult. Topical hemostatic agents and the argon beam coagulator are useful adjuncts for operative control of bleeding.

Allogenic liver transplantation is unlikely to become a viable option for the management of severe liver injuries in the foreseeable future. Although it has been performed for severely injured patients when conventional techniques fail to control the liver injuries, in a case series, the overall mortality rate was greater than 40 %, with 25 % of patients requiring a repeat transplant surgery (Kaltenborn et al. 2013).

Tract injuries of the liver, such as those caused by gunshot or stab wounds, create a unique circumstance in that external compression might fail to tamponade the bleeding. In these circumstances, tractotomy might not be possible based on the length, depth, and trajectory of the wound. Such injuries may be amenable to balloon or plug tamponade devices. Balloon tamponade devices are made by passing a red rubber catheter into a large Penrose drain. The free end of the Penrose drain is ligated, and the end that accepts the red rubber catheter is tied around the catheter itself, allowing instillation of water, saline, or contrast agent into the Penrose. The devise is passed through the tract and then inflated, thereby exerting circumferential tamponade along the length of the wound (Parks et al. 1999). Similarly, plugs can be made from numerous surgical materials such as collagen, Gelfoam, Vicryl, etc. that can be useful for occluding wounds. Omental pedicle flaps might provide similar effects with more favorable biologic profiles.

Complications after liver trauma can be particularly challenging to manage and occur in three major forms: hepatic necrosis, bile leak, and organ space surgical site infection (or abscess). These complications have been associated with increasing injury severity, hepatic angioembolization, and presence of concomitant hollow visceral injuries.

Hepatic necrosis has been associated with fever, leukocytosis, abnormal liver function tests, and abnormal liver synthetic function. The optimal treatment for hepatic necrosis is unknown. Some surgeons argue that sterile necrosis (in the setting of sufficient residual liver parenchyma) poses minimal danger to the patient. Small areas of liver necrosis can be managed expectantly. Large areas of compromised liver often require operative debridement or percutaneous drainage. In addition to liver parenchyma, the gallbladder is at risk for ischemia and necrosis if its arterial supply (based on the right hepatic artery) is ligated or embolized. Some surgeons have advocated preemptive cholecystectomy among these patients, but the optimal timing of that procedure is unknown.

Bile leaks occur in 10–15 % of patients with liver injuries. Hepatobiliary iminodiacetic acid (HIDA) scanning is the study of choice to rule out bile leak. Its negative predictive value approaches 100 %, but its specificity has been called into question. Treatment of posttraumatic bile leak varies greatly by institution and location of the leak. Techniques include open exploration, laparoscopic washout and drainage, percutaneous drainage, endoscopic retrograde cholangiography (ERCP) with sphincterotomy and stenting, pharmacotherapies, and observation. Early wide drainage of liver injuries has also proven useful in the diagnosis of posttraumatic bile leak. Although drains help to control bile peritonitis, the efficacy of drains in expediting closure of bile leaks is unknown.

Bile that is in communication with the pleural space must be drained. Most biliary-pleural fistulae can be successfully treated with tube thoracostomy and antibiotic therapy. Many surgeons advocate the use of ERCP sphincterotomy and stenting if a biliary leak is demonstrated. Other surgeons have reported favorable outcomes with a thoracoscopic approach for biliary-pleural fistulae, but high-quality data regarding complications and outcomes are lacking. Bronchobiliary fistulae should be managed early with surgical exploration because of the high rate of morbidity and mortality. In such cases, the subdiaphragmatic space should also be explored and well drained.

Abscesses develop in 5–10 % of patients with liver injuries, with higher rates among patients with penetrating trauma and coincident hollow visceral injuries. Most of these infections are effectively treated with percutaneous drainage and culture-guided antibiotic therapy. More severe infections, however, especially those associated with hepatic necrosis, require operative debridement and drainage.

Isolated non-iatrogenic extrahepatic bile duct injuries are exceedingly rare. Bile duct injuries that do occur are often found in combination with major injuries to the pancreas, duodenum, and IVC that require operative exploration. This constellation of injuries is frequently lethal, and survivor morbidity is extremely high. Nevertheless, early recognition and diagnosis of these injuries is crucial to their management. Intraoperative interrogation of the common bile duct is best achieved with cholangiography, most commonly through the gallbladder (or cystic duct stump if cholecystectomy is performed). Occasionally, cholangiography can be performed in a retrograde fashion through the ampulla of Vater. This should be reserved for patients with preexisting duodenal injuries. Intentional duodenostomy for purposes of retrograde cholangiography is not recommended.

Bile duct injuries that are discovered at the index operation should be repaired if patient physiology permits. Partial injuries can be repaired over a T tube if the blood supply is sufficient and the anastomosis is tension-free. Complete transections should be reconstructed with a choledochoduodenostomy or a choledochojejunostomy. These can be time-consuming reconstructions, however; and the resuscitation of the injured patient must take priority. Many of these patients are better served with ligation of the proximal and distal bile duct injuries, with temporary external biliary drainage via a cholecystostomy tube. Delayed definitive reconstruction can be performed at a later date. Alternatively, if an injury is not defined and the operation needs to be truncated, the area can be widely drained, and interrogated during subsequent operation or with imaging such as magnetic resonance cholangiopancreatography (MRCP).

If the injury complex does not mandate laparotomy as the first-line management and there is clinical suspicion of bile leak, patients should undergo HIDA scan followed by MRCP or ERCP if the bile ducts warrant further study. These injuries can most often be managed with endoscopic techniques and percutaneous drainage of biloma.