AAST Organ Injury Scale: Correlation of CT-Graded Liver Injuries and Operative Findings

The Organ Injury Scaling Committee of the AAST recently published a consensus classification of splenic, hepatic, and renal injuries (J Trauma, 291664, 1989). The hepatic injury scale (HIS), based on parenchymal laceration and intrahepatic hematoma, includes grades 1 to 6, representing the least to most severe injury. This study classifies liver injuries by findings at celiotomy, correlates operative findings with transfusion requirements and method of management of liver injury, and relates preoperative CT to anatomic findings at laparotomy. Thirty-seven patients with blunt liver injury were evaluated by abdominal CT with and without intravenous contrast and then underwent celiotomy. Increasing operative HIS correlated well with increasing severity of injury as measured by transfusions and operative management. Thirty-one CT grades did not correlate with operative findings (84%). Four patients had intrahepatic hematomas that were not discovered at operation. Twelve lacerations were graded too high by CT and 15 too low. Of these 15, ten CT scores were at least two grades lower than operative findings. Injuries around the falciform ligament occurred in three of the low misclassifications. One patient with intrahepatic hematoma developed hepatic artery pseudoaneurysm. We conclude that the HIS readily characterizes operative findings of hepatic lacerations and that increasing operative grade correlates well with transfusion requirements and operative management. CT can define intrahepatic hematomas, but does not correlate well with hepatic lacerations. Extreme caution is required when using CT alone to define “minimal” liver injury for prospective management of blunt trauma victims.