Artificial ascites using the guidewire technique during microwave ablation in the liver dome: technique and analysis of fluid repartition

Purpose To describe the guidewire technique to perform hydrodistension and create artificial ascites during liver microwave ablation (MWA) of tumors located in the hepatic dome and evaluate the effectiveness of repartition of peritoneal fluid along segments VII and VIII with this technique. Materials and methods A retrospective review of all 18 consecutive patients who benefited from MWA combined with hydrodistension causing artificial ascites performed with the guidewire technique was conducted. The technique involves inserting a 20G spinal needle in the liver parenchyma and catheterizing the peritoneum with a 0.018 nitinol guidewire while retrieving the needle from the liver. Technical success was defined by the successful insertion of a sheath over the wire in the peritoneal cavity and identification of peritoneal fluid on CT images, with repartition of ascites around segments VII and VIII. Results Target tumors were located in segments VII and VIII and had a mean size of 27.7 mm with a mean distance from the diaphragm of 1.7 mm. Technical success of artificial ascites was 14/18 (78%). In the four cases where artificial ascites failed, patients had undergone previous liver surgery. In the 14 cases for which artificial ascites were successful, complete separation of the diaphragm from the ablation zone was noted in 9/14 cases and partial separation in 5/14 cases. Conclusion Hydrodistension with the guidewire technique is effective and safe to accomplish artificial ascites. The extent of repartition of peritoneal fluid is variable, especially in the peritoneal recess in contact with the bare area where diffusion of fluid was variable.