A New Liver Explant Fixation Technique

Abstract

To the Editor.—Surgical intervention, including orthotopic liver transplantation, is a common modality used in the treatment of hepatocellular carcinoma. Accurate pathologic information is important to clinicians for appropriate staging and prognostication of such patients, particularly the identification of tumor multifocality. To identify all potentially neoplastic nodules, a meticulous gross examination is necessary.The gross examination of liver explants typically involves “bread-loafing” the specimen into slices as thin as practicably possible, ideally 0.5 cm or less in thickness. However, obtaining thin, uniform slices may be challenging in large unfixed hepatectomy specimens. In clinical practice, irregular slices thicker than 0.5 cm are frequently obtained, which increases the frequency of missed lesions, particularly small lesions. In addition, correlation with preoperative imaging studies becomes increasingly difficult in specimens cut irregularly.Formalin fixation firms the gross liver texture and improves the cutting process, making possible more uniform slices as compared with unfixed liver specimens. Ideally, formalin fixation should occur evenly throughout the entire liver parenchyma. Immersing intact specimens in formalin is generally inadequate for this purpose as formalin permeates through tissue slowly, resulting in a thin rind of fixed liver surrounding an unfixed core. To achieve uniform fixation, a group at Mayo Clinic (Rochester, Minn) developed a perfusion process that delivers formalin throughout the vasculature of the entire specimen1 via a continuous-perfusion pump for 3 days. This process is slow, labor intensive, and requires specialized equipment.An alternative technique that is quick, easy to use, inexpensive, and effective is herein described. It involves the use of an appropriately sized Foley catheter to cannulate the large vessels of the explanted liver (Figure 1). Once cannulated, the balloon cuff is inflated to prevent backflow. A catheter tip 60-mL syringe is then used to perfuse formalin into the hepatic vasculature. The entire process can be performed in less than 30 minutes. Because high pressures can easily be produced during perfusion that may inadvertently produce artifactual damage it is recommended that the force of only one hand be used. Good fixation results have been achieved with as little as 200 mL of formalin per large vessel (Figure 2). Following formalin perfusion, the intact specimen is floated in a bath of formalin overnight.In our experience, cannulation and perfusion of only the hepatic veins suffices to achieve adequate fixation. Portal vein cannulation is generally unnecessary but may be performed if anatomy permits. Hepatic artery cannulation is technically challenging and is of negligible added value.This technique results in a well-fixed, firm specimen that is easily sliced at the requisite 0.5-cm intervals, making possible a meticulous gross examination that aids in the identification of even small liver nodules.