Percutaneous Radiofrequency Ablation of Hepatic Tumors against the Diaphragm: Frequency of Diaphragmatic Injury1

PURPOSE: To retrospectively determine the frequency of diaphragmatic injury when percutaneous hepatic radiofrequency (RF) ablation is performed adjacent to the diaphragm. MATERIALS AND METHODS: Institutional Review Board approval was obtained for our HIPAA-compliant study. Informed consent for the ablation procedure and for use of related data for future research was obtained from each patient. A retrospective review was conducted of 215 patients undergoing percutaneous RF ablation of hepatic tumors. Twenty-nine patients (21 men and eight women; age, 41-89 years) were identified with tumors abutting the diaphragm. Episodes of right shoulder pain were recorded. A panel of radiologists blinded to the patients' clinical histories reviewed their imaging for evidence of diaphragmatic injury and ablation success. A generalized estimating equation model and the Fisher exact test were used for statistical analysis. RESULTS: The 29 patients had a total of 33 tumors abutting the diaphragm. Tumor size was 1.3-5.5 cm (mean, 3.2 cm +/- 1.1). After ablation, five (17%) patients reported right shoulder pain. In four, pain was mild or moderate, with symptoms lasting 2-14 days (median, 5.5 days). Three of these showed diaphragmatic thickening on postablation computed tomographic (CT) scans. One patient had severe pain lasting 2 weeks, followed by milder pain for 2 months. This patient's postablation CT images showed focal nodular diaphragmatic thickening. This patient was treated with a multitined device; the other four, with straight-needle devices. Local tumor progression was seen in 14 tumors (42.4%). Tumors 3 cm or smaller had a much lower local progression rate than tumors larger than 3 cm (12.5% vs 70.6%). CONCLUSION: Of 29 patients who had ablation of hepatic tumors adjacent to the diaphragm, five (17%) had diaphragmatic injury, which was clinically apparent with right shoulder pain.