New Radiofrequency Device to Reduce Bleeding after Core Needle Biopsy: Experimental Study in a Porcine Liver Model

Abstract

Objective: To evaluate the in vivo efficiency of the biopsy tract radiofrequency ablation for hemostasis after core biopsy of the liver in a porcine liver model, including situations with bleeding tendency and a larger (16-gauge) core needle.

Materials and methods: A preliminary study was performed using one pig to determine optimal ablation parameters. For the main experiment, four pigs were assigned to different groups according to heparinization use and biopsy needle caliber. In each pig, 14 control (without tract ablation) and 14 experimental (tract ablation) ultrasound-guided core biopsies were performed using either an 18- or 16-gauge needle. Post-biopsy bleeding amounts were measured by soaking up the blood for five minutes. The results were compared using the Mann-Whitney U test.

Results: The optimal parameters for biopsy tract ablation were determined as a 2-cm active tip electrode set at 40-watt with a tip temperature of 70-80℃. The bleeding amounts in all experimental groups were smaller than those in the controls; however they were significant in the non-heparinized pig biopsied with an 18-gauge needle and in two heparinized pigs (p < 0.001). In the heparinized pigs, the mean blood loss in the experimental group was 3.5% and 13.5% of the controls biopsied with an 18- and 16-gauge needle, respectively.

Conclusion: Radiofrequency ablation of hepatic core biopsy tract ablation may reduce post-biopsy bleeding even under bleeding tendency and using a larger core needle, according to the result from in vivo porcine model experiments.

Keywords: Biopsy; Complications; Core biopsy tract ablation; Experimental study; Hemorrhage; Liver; Pulsed radiofrequency treatment.

Figures

Fig. 1. Newly developed thermocouple-monitored radiofrequency biopsy tract ablator.

Insulation sheath with electrode in place: device is composed of 1) 2 cm-long active electrode tip, 2) insulation sheath covered by polyester, 3) sheath handle, 4) electrode handle, 5) multi cable, and 6) connector.

Fig. 2. US-guided biopsy procedure and assessment of blood loss from biopsy site.

A. US image during tract ablation procedure after core biopsy, combination of 2-cm active electrode tip (arrowheads, “1” in Figure 1) and insulation sheath (arrow, “2” in Figure 1) retracted together while monitoring temperature of electrode tip. B. Insulation sheath with engaged automated biopsy gun in place. 0.5-cm biopsy needle tip (arrow) protrudes from end of insulation sheath. US-guided liver biopsy was performed in coaxial manner through insulation sheath. C. Any blood from site (arrows) was soaked with dry gauze pads for five minutes without touching needle tract and was estimated by reweighing gauze pads. D. Two biopsy sites after measuring amount of blood loss and electrocauterization. Lesion at left upper was control biopsy site and lesion in right lower was experimental biopsy site. Arrowheads and arrows demonstrate electrocauterized points and RF electrode path with burn, respectively. RF = radiofrequency, US = ultrasound