Expansion of radiofrequency ablation volume by saturated NaCL saline injection in the area of vaporization

Abstract

Background: Vaporization around the radiofrequency (RF) electrode after RF application (RFA) limits the RF ablation area. Purpose: To determine whether saturated saline injected into the area of vaporization after initial RFA extends ablation area after further RFA. Material and Methods: RFA was performed in 18 ex vivo porcine livers and four in vivo rabbit erector spinae muscles. An RF electrode was used to ablate an area with 40W of parallel current for 15 min. The ablation margin was determined using a thermocouple, and the radius of the ablated area was measured. After RF electrode removal, saturated saline was infused through a percutaneous ethanol injection needle into the site of the original RFA in 11 liver samples and two erector spinae muscles. Three minutes later, RFA was resumed for 15 min. The remaining seven control liver samples and two spinae muscles received RFA without saline injection. The radius of the final ablated area was then measured. Results: In the ex vivo study, injection of saturated saline significantly decreased tissue impedance (87.799.4 to 51.199.7V, P B0.0001), and increased the mean radius of the ablated area (15.993.0 to 25.093.6 mm, P B0.0001). These significant changes were not observed without injection of saturated saline. Similar trends were found in the in vivo study. Conclusion: Injection of saturated saline into the area of vaporization around the RF electrode, followed by additional RFA, caused concentric expansion of the final ablation area, facilitating more efficient tumor ablation.

Maximizing Parameters for Tissue Ablation by Using an Internally Cooled Electrode

“…Pulsing energy, as noted by the manufacturer, "by operating at intervals of low output and high output, the local tissue is allowed to partially cool." Consequently, the tissue is able to accept greater energy ( 17 ). Furthermore, Solazzo et al ( 18 ) have shown that maximum coagulation was achieved by using a 3-cm single electrode at a high-pulse power setting: on for 10-18 seconds and off for 11-20 seconds.…”

Radiofrequency Ablation and Microwave Ablation in Liver Tumors: An Update

“…So, RFA is limited by increasing in impedance and an excessive local temperature . Several technical devices exist to avoid this effect, such as monitoring temperature or impedance during procedure or simultaneously instilling saline solution into the tissue surrounding the RF needle .…”

Minimally Invasive Therapies for Hepatocellular Carcinoma: Mechanisms of Local Control and Systemic Immunologic Response

“…Injection of NaCl-containing solutions has also been explored to overcome the heat sink effect [16,[19][20][21]. Pre-treatment with hypertonic saline, 5-36%, results in significantly higher temperatures and a significantly larger ablation zone when compared to no pre-treatment [19,20].…”

“…Pre-treatment with hypertonic saline, 5-36%, results in significantly higher temperatures and a significantly larger ablation zone when compared to no pre-treatment [19,20]. The NaCl solutions can be injected at any point during the procedure to expand the size of the ablation zone [21].…”