Hepatic hemorrhage caused by percutaneous tumor ablation: radiofrequency ablation versus cryoablation in a porcine model.

Purpose: To determine the extent of hepatic hemorrhage caused by percutaneous cryoablation performed with a small-diameter cryoablation probe compared with that caused by percutaneous radiofrequency (RF) ablation in a porcine model.

Materials And Methods: The study was pre-approved by the institutional research animal care and use committee, and husbandry and experiments complied with National Institutes of Health standards for care and use of laboratory animals. Percutaneous hepatic ablation was performed in 18 domestic pigs (mean weight, 45 kg) by using a 17-gauge (1.5-mm-diameter) RF electrode (n = 6), a cluster of three RF electrodes (n = 6), or a 13-gauge (2.4 mm-diameter) cryoprobe (n = 6). Ablation was performed in four sites per liver. Total blood loss, minimum lesion diameter, maximum lesion diameter, and lesion volume were determined for each group and compared by using analysis of variance.

Results: Mean blood loss was 11.11 mL +/- 11.47 (standard deviation), 105.29 mL +/- 175.58, and 28.06 mL +/- 30.97 with the single RF electrode, RF electrode cluster, and cryoablation probe, respectively. Mean minimum and maximum lesion diameters were largest with the RF electrode cluster (2.40 and 3.98 cm, respectively), followed by the cryoablation probe (2.38 and 3.94 cm) and single RF electrode (1.49 and 2.63 cm). Mean minimum and maximum lesion diameters were significantly different between the single RF electrode and the RF electrode cluster, as well as between the single RF electrode and the cryoablation probe (P < .001). Mean lesion volume was largest for the RF electrode cluster (24.03 cm3), followed by those for the cryoablation probe (17.46 cm3) and single RF electrode (9.05 cm3) (single RF electrode vs cryoablation probe, P < .05). Lesion volumes were not significantly different with the RF electrode cluster versus the single RF electrode (P = .052) or with the RF electrode cluster versus the cryoablation probe (P = .381).

Conclusion: Mean blood loss from percutaneous cryoablation in this model was between that for RF ablation with the single electrode and that for RF ablation with the electrode cluster.