A multi-step, incremental expansion method for radio frequency ablation: optimization of the procedure to prevent increases in intra-tumor pressure and to reduce the ablation time
Article first published online: 22 MAR 2005
Volume 25, Issue 3, pages 542–547, June 2005
How to Cite
Kotoh, K., Nakamuta, M., Morizono, S., Kohjima, M., Arimura, E., Fukushima, M., Enjoji, M., Sakai, H. and Nawata, H. (2005), A multi-step, incremental expansion method for radio frequency ablation: optimization of the procedure to prevent increases in intra-tumor pressure and to reduce the ablation time. Liver International, 25: 542–547. doi: 10.1111/j.1478-3231.2005.01051.x
- Issue published online: 20 MAY 2005
- Article first published online: 22 MAR 2005
- Received 3 June 2004, accepted 24 August 2004
- ablation time;
- hepatocellular carcinoma (HCC);
- intra-tumor pressure;
- multi-step expansion;
- radio frequency ablation (RFA);
- single-step expansion
Abstract: Background/Aims: Radio frequency ablation (RFA) has been accepted clinically as a useful local treatment for hepatocellular carcinoma (HCC). However, intra-hepatic recurrence after RFA has been reported. We initially hypothesized that recurrence was attributable to increases in intra-tumor pressure during RFA, and we subsequently measured the pressure and optimized the procedure.
Methods: A block of pig liver sealed in a rigid plastic case was used as a model of an HCC tumor with a capsule. We compared the pressure between a single-step full expansion of the needle (single-step method) and incremental, stepwise expansion (multi-step method), and evaluated the effect of varying the electrical power. Finally, we performed a preliminary comparison of the ablation times for these methods in HCC cases.
Results: The multi-step method resulted in a significantly lower pressure and shorter total ablation time than the single-step method. Furthermore, incremental expansion in 10 steps resulted in a lower pressure and shorter ablation time than four steps. Seventy W-ablation resulted in a lower pressure and shorter time than 30- or 50 W-ablation. In HCC cases, the multiple-step method had a significantly shorter ablation time than the single-step method.
Conclusion: The multi-step method can be recommended to reduce the ablation time, and suppress the increase in pressure.