Accuracy and effectiveness of laparoscopic vs open hepatic radiofrequency ablation

The purpose of this study was to compare the accuracy (in terms of ultrasound-guided probe placement) and the effectiveness (in terms of pathologic tumor-free margin) of laparoscopic vs open radiofrequency (RF) ablation. Using a previously validated tissue-mimic model, 1-cm simulated hepatic tumors were ablated in 10 pigs randomized to open or laparoscopic techniques. Energy was applied until tissue temperature reached 100 degrees C (warm-up) and thereafter for 8 min. A pathologist blinded to technique examined all specimens immediately after treatment. Analysis was by Fisher's exact test and the Mann-Whitney U test; p < 0.05 was considered significant. Off-center distance (3.5 +/- 1.6 vs 4.2 +/- 1.4 mm), size (24.7 +/- 3.1 vs 25.6 +/- 3.8 mm), symmetry (40% vs 73%), margin positivity (33% vs 9%), and margin distance (1.1 +/- 1.2 vs 2.2 +/- 1.6 mm) were not significantly different between laparoscopic (n = 15) and open (n = 11) ablations, respectively. The proportion of round/ovoid lesions (20% vs 64%) was lower (p = 0.043), and warm-up time (20.2 +/- 14.0 vs 10.7 +/- 7.5) was longer (p = 0.049) for the laparoscopic than for the open groups, respectively. Accurate probe placement can be achieved using laparoscopic and open RF ablation techniques. The physiologic effects of laparoscopy may alter ablation shape and warm-up time. Additional studies are needed to establish effective ways of achieving complete tumor destruction.