**2. Mechanism of injury**

Injury to liver ranges from major and serious to minor non serious injuries. It can extend from minor subcapsular hematomas and small capsular lacerations to major deep parenchymal lacerations, major crush injury, and vascular avulsion. Many factors contribute to the vulner‐ ability of liver to injury in trauma. The liver is the biggest solid abdominal organ. It is sur‐ rounded by many organs and have attachments with peritoneal ligaments, giving it a relatively fixed position. Liver is anterior in the abdominal cavity in right upper quadrant. It is highly vascular in nature and has fragile parenchyma. The support of Glisson's capsule is easily disrupted making this organ vulnerable to injury. Motor vehicle accident is the most common cause of blunt liver injury.

Not surprisingly, even in the penetrating abdominal trauma, the liver is the second most commonly injured organ [6]. Most common cause of penetrating liver injury are due to knife assaults and gunshot wound. The severity of penetrating injury depends upon the trajectory of the missile or implements. The injuries can range from simple parenchymal injuries or se‐ rious and major vascular laceration [7].

During respiration, the liver margin, which can usually be palpated 2 to 3 cm below the right rib margin, rises and falls with the diaphragm. With expiration the dome of the liver rises as high as the level of nipple which is T4. This association with chest wall also makes liver vulnerable during injuries to chest. Furthermore, the penetrating injuries in the lower abdomen can cause serious trauma to liver as the inferior margin of the liver descends to as low as T12 with deep inspiration. [8].

The liver remains the most frequently and seriously injured abdominal organ due to trauma. About 31% patients of polytrauma have abdominal injuries. Almost 13% and 16% of cases have spleen and liver injuries, respectively, and pelvic injuries are seen in about 28% of cases. In close location of many organs, it is difficult to make differential diagnosis between pelvic or

In abdominal injuries, liver trauma is the leading cause of death. The most common way liver gets injured is in blunt abdominal trauma. By trauma, the identification of serious intraabdominal injuries is a challenging task; many injuries may not be apparent during the initial assessment and treatment period. Since the liver gets frequently injured with other abdominal organs following abdominal trauma, associated injuries contribute significantly to mortality and morbidity and may cause the liver injury to be masked and diagnosis delayed. The management of hepatic injuries has evolved over the past 30 years. Previously, a diagnostic peritoneal lavage (DPL) was done to find out active bleeding and to diagnose missed intraabdominal injuries needing surgical intervention. If DPL is positive for blood, it was an indication for exploratory celiotomy. Nowadays, it is recognized that between 50% and 80% of liver injuries stop bleeding spontaneously. In addition, there is better imaging of the injured liver by computed tomography (CT). Both these factors have led progressively to the accept‐ ance of nonoperative management (NOM) and a resultant decrease in mortality rates [4, 5].

Injury to liver ranges from major and serious to minor non serious injuries. It can extend from minor subcapsular hematomas and small capsular lacerations to major deep parenchymal lacerations, major crush injury, and vascular avulsion. Many factors contribute to the vulner‐ ability of liver to injury in trauma. The liver is the biggest solid abdominal organ. It is sur‐ rounded by many organs and have attachments with peritoneal ligaments, giving it a relatively fixed position. Liver is anterior in the abdominal cavity in right upper quadrant. It is highly vascular in nature and has fragile parenchyma. The support of Glisson's capsule is easily disrupted making this organ vulnerable to injury. Motor vehicle accident is the most common

Not surprisingly, even in the penetrating abdominal trauma, the liver is the second most commonly injured organ [6]. Most common cause of penetrating liver injury are due to knife assaults and gunshot wound. The severity of penetrating injury depends upon the trajectory of the missile or implements. The injuries can range from simple parenchymal injuries or se‐

During respiration, the liver margin, which can usually be palpated 2 to 3 cm below the right rib margin, rises and falls with the diaphragm. With expiration the dome of the liver rises as high as the level of nipple which is T4. This association with chest wall also makes liver vulnerable during injuries to chest. Furthermore, the penetrating injuries in the lower abdomen can cause serious trauma to liver as the inferior margin of the liver descends to as low as T12

intractable abdominal injuries [2, 3].

300 Recent Advances in Liver Diseases and Surgery

**2. Mechanism of injury**

cause of blunt liver injury.

with deep inspiration. [8].

rious and major vascular laceration [7].

**Type A injury**: Patients suffer from rupture of the left liver lobe mostly along the falciform ligament, including segment II, III, or IV of the liver. This injury pattern is observed when the trauma has a direct frontal impact of the trauma energy.

**Type B injury:** These injuries represent mechanisms of trauma with a more complex pattern of energy, with impacts coming from several directions, affecting segments V–VIII of the liver.

**Figure 1. Type of liver injury Figure 1.** Mechanism of blunt liver trauma and the type of liver injury

3 **3. Assessment of liver trauma**  The right liver lobe is more often involved, owing to its larger size and proximity to the ribs. Compression against the fixed ribs, spine or posterior abdominal wall generally result in predominant damage to posterior segments (segments 6, 7, and 8) of the liver (>85%). Inversely, a blow to the right hemithorax may propagate through the diaphragm producing contusion of dome of right lobe of liver. Liver's ligamentous attachments to diaphragm and posterior abdominal wall act as sites of shearing forces during deceleration injury. Liver injury can also occur as a result of transmission of excessively high venous pressure to remote body sites at the time of impact. Weaker connective tissue framework, relatively large size, and incomplete maturation and more flexible ribs account for higher chance of liver injury in children compared to adults. Deceleration injuries producing shearing forces may tear hepatic lobes and often involve the inferior vena cava and hepatic veins. While a steering column injury can damage an entire lobe. In general, liver trauma may result in subcapsular/intrahepatic hematomas, lacerations, contusions, hepatic vascular injury, and bile duct injury [9, 10].

Based on the mechanism and site of blunt liver trauma, the liver injury could be classified into two types, type A and B as described in (Figure 1) [11].
