Dynamics of liver trauma: tearing of segments III and IV at the level of the hepatic ligament

The liver is the most commonly injured intra-abdominal organ. Liver mass is the key factor in determining the extent of the inertial force and consequently of damage in the case of sudden deceleration. In this respect, high-speed accidents usually produce characteristic lesions where the III-IV segments tear at the level of the hepatic ligament causing grade I-III liver injuries. The pathophysiology of such traumas is the subject of the present contribution. All trauma patients who sustained a blunt abdominal injury from January 1 to December 31 2004 were identified by the trauma registry at the Policlinico di Tor Vergata In order to select high-speed and sudden deceleration traumas, clinical records were reviewed for demographics, severity of injury, severity of liver injury, associated concomitant injuries, and management scheme. The grade of liver injury was determined on the basis of the initial CT or the intraoperative findings. A total of 159 patients who incurred abdominal injuries due to blunt trauma were identified. In 14 (8.8 percent) one or more liver lesions were associated. Among the low-grade injuries, 3 were grade I, and 8 grade II. Forty percent were high-grade injuries consisting in 6 grade III and 1 grade IV. We observed no grade V or grade VI injuries in this series. The most frequent occurrence was a tear between hepatic segments III and IV caused by the acute impact of the liver on the hepatic ligament. A hepatic injury caused by the round ligament was diagnosed intraoperatively in 1 out of 5 liver trauma patients (20 percent) and preoperatively in 4 out of 5 (80 percent) in our one-year abdominal blunt trauma series. Our clinical contribution underlines the high frequency of such lesions that seems to be related to, and characteristic of, high-speed trauma. In these cases immediate deceleration due to the impact may be a relevant factor in the pathophysiology of the lesion.