Objective: The capsular extent of traumatic hepatic lacerations may be limited to the bare area of the liver--an area not covered by peritoneal reflection. In these cases, intraperitoneal bleeding may not occur, classic peritoneal findings may be absent, and results of diagnostic peritoneal lavage may be normal. We undertook a study to evaluate the frequency, CT appearance, and significance of injury of the bare area of the liver.
Materials and methods: We retrospectively reviewed radiologic reports of 1469 hemodynamically stable trauma patients referred for abdominal CT between January 1986 and September 1992 and selected 155 patients whose CT reports indicated hepatic injury. Retrospective review of the abdominal CT scans of these 155 patients confirmed intrahepatic laceration or contusion in all of them. The study involved the 25 (16%) patients in whom the capsular extent of injury was limited to the bare area of the liver.
Results: In all cases, CT scans showed simple or complex lacerations involving predominantly or exclusively the posterior segment of the right hepatic lobe, with capsular extent limited to the superomedial hepatic surface. Abnormal retroperitoneal findings were present in all but two cases. Twenty-two (88%) of 25 patients had right-sided retroperitoneal hemorrhage or fluid collections; adrenal hematoma or periadrenal fluid was seen in 12 (48%) patients. Abnormal pericaval fluid collections were present in nine (36%). Only five (20%) patients had free intraperitoneal fluid. Diagnostic peritoneal lavage, performed as a correlative procedure in four patients, revealed intraabdominal hemorrhage in one, equivocal findings in one, and normal findings in two. Patients who had isolated injuries of the bare area of the liver did well clinically and were discharged after an uneventful hospital stay of an average of 3 days (range, 2-7 days).
Conclusion: A small percentage of hemodynamically stable patients who have hepatic trauma may have lacerations that primarily involve the bare area and that are not suspected clinically or detected by diagnostic peritoneal lavage. In these patients, CT may be helpful to show the extent of liver injury, identify associated retroperitoneal abnormalities, and provide prognostic information.