Percutaneous Radiofrequency Ablation of Hepatocellular Carcinomas: Factors Related to Intraprocedural and Postprocedural Pain

OBJECTIVE. The purpose of our study was to evaluate the factors related to intraprocedural and postprocedural pain during radiofrequency ablation of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS. For this retrospective study, we included 145 patients with 160 HCCs who underwent percutaneous radiofrequency ablation under local and IV conscious sedation from January 2006 to December 2006. Patients' pain was scored using the visual analog scale (VAS) immediately after the procedure. Medical records with CT images were reviewed for patient factors, tumor characteristics, and procedural factors. We determined factors correlated with the higher level of intraprocedural pain and the difference in intraprocedural VAS between a group requiring additional analgesics while hospitalized and a group not requiring more analgesics. Statistical analysis was performed using the two-sample Wilcoxon's rank sum test, the Kruskal-Wallis test, and partial Spearman's correlation analysis. RESULTS. On univariate analysis, patients with large tumors, previously untreated tumors, tumors adjacent to the parietal peritoneum, and those who had undergone multiple ablations and longer duration of ablation reported a higher VAS during the procedure. A significant correlation was seen between the distance of a tumor from the parietal peritoneum and the VAS. On multivariate analysis, tumor location adjacent to the parietal peritoneum was an independent predictor for a higher level of self-reported pain. A group requiring additional analgesics while hospitalized reported a higher VAS than patients not requiring more analgesics. CONCLUSION. The location of a tumor adjacent to the parietal peritoneum is an independent predictor of higher pain level during percutaneous radiofrequency ablation of HCCs. Modification of intraprocedural anesthesia should be considered in patients with risk factors for increased pain.