Computed Tomography-guided Radiofrequency Ablation for Sub-diaphragm Hepatocellular Carcinoma: Safety and Efficacy of Inducing an Artificial Pneumothorax.

We retrospectively evaluated the safety and efficacy of artificial pneumothorax induction to perform computed tomography (CT)-guided radiofrequency ablation (RFA) for sub-diaphragm hepatocellular carcinomas (HCCs). From June 2008 to October 2010 at our institution, 19 HCCs (16 patients) were treated using CT-guided RFA after artificial pneumothorax induction. A 23-G needle was inserted into the liver surface at a site of 2 connected pleurae without lung tissue. After a small amount of air was injected, the pleural space widened, creating a small pneumothorax. Additional air was insufflated via a newly inserted 18-G cannula to raise the lung away from the planned puncture line for RFA. The electrode was then advanced transthoracically. Ablation was performed using a cool-tip electrode with manual impedance control mode. The injected air was then aspirated as much as possible. Artificial pneumothorax was successfully induced in all cases. The average total volume of injected air in each case was 238ml. No artificial pneumothorax-related complication occurred; lung injury occurred in one case during RF electrode insertion. No local progression occurred during follow-up. Recurring HCCs were observed in eight patients. Artificial pneumothorax induction is safe and effective for CT-guided RFA of sub-diaphragm HCCs, which are difficult to locate on US.