School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia.
School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia; Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia.
Comput Methods Programs Biomed. 2021 Nov;211:106436. doi: 10.1016/j.cmpb.2021.106436. Epub 2021 Sep 24.
Saline infusion is applied together with radiofrequency ablation (RFA) to enlarge the ablation zone. However, one of the issues with saline-infused RFA is backflow, which spreads saline along the insertion track. This raises the concern of not only thermally ablating the tissue within the backflow region, but also the loss of saline from the targeted tissue, which may affect the treatment efficacy.
In the present study, 2D axisymmetric models were developed to investigate how saline backflow influence saline-infused RFA and whether the aforementioned concerns are warranted. Saline-infused RFA was described using the dual porosity-Joule heating model. The hydrodynamics of backflow was described using Poiseuille law by assuming the flow to be similar to that in a thin annulus. Backflow lengths of 3, 4.5, 6 and 9 cm were considered.
Results showed that there is no concern of thermally ablating the tissue in the backflow region. This is due to the Joule heating being inversely proportional to distance from the electrode to the fourth power. Results also indicated that larger backflow lengths led to larger growth of thermal damage along the backflow region and greater decrease in coagulation volume. Hence, backflow needs to be controlled to ensure an effective treatment of saline-infused RFA.
There is no risk of ablating tissues around the needle insertion track due to backflow. Instead, the risk of underablation as a result of the loss of saline due to backflow was found to be of greater concern.
盐水灌注与射频消融（RFA）联合应用以扩大消融区域。然而，盐水灌注 RFA 的一个问题是回流，它会沿着插入轨迹扩散盐水。这不仅引起了对回流区域内组织进行热消融的关注，而且还引起了对从目标组织中丢失盐水的关注，这可能会影响治疗效果。
在本研究中，开发了二维轴对称模型，以研究盐水回流如何影响盐水灌注 RFA，以及上述担忧是否有根据。盐水灌注 RFA 使用双孔隙焦耳加热模型来描述。回流的流体动力学通过假设流动类似于薄环中的流动来使用泊肃叶定律来描述。考虑了回流长度为 3、4.5、6 和 9cm 的情况。
结果表明，不存在回流区域内组织热消融的担忧。这是由于焦耳加热与距电极的距离的四次方成反比。结果还表明，较大的回流长度会导致沿回流区域的热损伤更大的增长，并导致凝固体积更大的减少。因此，需要控制回流以确保盐水灌注 RFA 的有效治疗。
由于回流，不会有针插入轨迹周围的组织被消融的风险。相反，由于回流导致盐水丢失而导致的消融不足的风险被认为是更大的关注点。
