[Analyze the factors influencing multi-electrode synchronous radiofrequency ablation via switching controller in ex vivo bovine liver].

Objective: To investigate the effects of different electrode exposed end and different ablated time on lesion size of Cool-tip multi-electrode synchronous radiofrequency ablation via switching controller in ex vivo bovine liver.

Method: Twelve combinations of different electrode exposed end (2 cm, 3 cm and 4 cm) were used, and different ablated time (12, 16, 20 and 24 mins) was as experimental parameter. Ablated lesions in longitudinal diameter, transverse diameter and volume were measured. Analyze the factors influencing the lesion size with ANOVA or t test.

Results: The ablated lesions with 3 cm exposed end electrodes were more stable and the spheroidal rate is more close to 1. When ablated 24 mins with 4 cm exposed end electrodes, the longitudinal diameter, transverse diameter and volume were (7.66±0.21), (6.50±0.34) cm and (172±12) cm3, respectively. When the ablated time was constant, the lesions increased with the exposed end length of the electrodes increased. All the data among groups was statistically significant (P<0.01) unless the transverse diameters between 3 and 4 cm exposed end electrode. When the exposed end length of electrodes was constant, the lesions increased with the ablated time increased as a whole. But there was no significant difference in most of the adjacent groups. Only the longitudinal diameters and volumes of 4 cm exposed end electrodes between 20 and 24 min were statistically significant (P<0.05).

Conclusion: Within the experimental range, the lesion size ablated by Cool-tip multi-electrode synchronous radiofrequency ablation via switching controller increased with the electrode exposed end and ablated time increased. The spheroidal rate of the ablated lesions with 3 cm exposed end is more close to 1.