金属细针对射频消融离体猪肝热场的影响

目的观察金属细针对射频消融（RFA）离体猪肝热场的影响，探索利用金属细针引导产生适形消融范围的新方法。方法对11个离体家猪肝脏行RFA，以射频电极为对称轴，在射频针一侧按不同距离插入多根22GChiba针作为实验组，对称一侧正常肝脏作为对照组。对实验组所有Chiba针均进行针体绝缘处理，以针尾连接回路电极板的Chiba针组为A亚组，不连接回路电极板的Chiba针组为B亚组。分别对实验组和对照组的消融范围进行大体标本测量和光镜组织学分析，比较其差别。结果Chiba针与射频电极距离≤2．5cm时，A亚组的消融范围明显大于对照组（P〈0．05），B亚组的消融范围与对照组差异均无统计学意义（P均〉0．05）；Chiba针与射频针距离〉2．5cm时，实验组与对照组消融范围基本一致（P均〉0．05）。结论与回路电极板形成直接电流回路的金属细针在与射频电极一定距离内可增强射频消融热效应，不形成直接电流回路的金属细针不会对射频消融造成明显热影响。

Thermal influence of metal fine needles on radiofrequency ablation of in vitro porcine liver

Objective To observe the thermal influence of metal fine needles on radiofrequency ablation （RFA）, in order to develop a new procedure for conformal RFA by taking advantage of metal fine needles. Methods RFA was conducted in 11 in-vitro porcine livers. Taking radiofrequency electrode as symmetry axis, the side containing Chiba needles （22G） was set as test group, and the symmetry side without Chiba needles was set as control group. All Chiba needles in test group were insulated in the needle bar, and those in test group were divided into subgroup A and subgroup B. The needle ends in subgroup A were connected to grounding pads through electric wires, while those in subgroup B were not connected to grounding pads. The gross coagulation scopes were measured in order to compare the difference between the test group and control group and then were assessed under microscopy. Results When the distance between Chiba needle and radiofre- quency electrode was ≤2.5 cm, coagulation scopes in subgroup A were larger than those in control group （all P〈0.05）, while those in subgroup B and control group were not significantly different （all P〉0.05）. When the distance between Chiba needle and RFA electrode was 〉2. 5 cm, coagulation scopes were not significantly different in both groups （all P〉 0.05）. Conclusion Metal fine needle connected to grounding pads apparently enhances thermal effect on RFA within a cer- tain distance to radiofrequency electrode, while that unconnected to grounding pads causes little thermal influence on RFA.