PURPOSE: To evaluate diaphragmatic hernias (DH) after percutaneous radiofrequency ablation (PRFA) for basal lung nodules and to detect risk factors. MATERIALS AND METHODS: Between January 2009 and December 2012, the presence of DH was retrospectively recorded in all of the patients who underwent PRFA with multitine expandable electrodes for ablation of nodules in the lower lobe. All nodules were classified into three groups according to the location of the tines after deployment relative to the diaphragm: In group 1, the tines were at a distance of >1 cm from the diaphragm; in group 2, at least one tine was in contact with the diaphragm without perforation; and in group 3, at least one tine was perforating the diaphragm. RESULTS: We recorded 4 cases of DH (3 on the left side, 1 on the right side) in 156 patients (2.3% of procedures). The delay of onset was 7.8 months. DH occurred in groups 2 (n = 1) and 3 (n = 3). Only the 3 cases that occurred on the left side were symptomatic (2 intussusceptions and 1 gastroesophageal reflux) and were surgically repaired. The electrode was positioned in the center of the diaphragm in all cases. CONCLUSION: The central position of the electrode and the contact of at least one tine with the diaphragm after deployment seem to be a risk factor to develop DH.
PURPOSE: To evaluate diaphragmatic hernias (DH) after percutaneous radiofrequency ablation (PRFA) for basal lung nodules and to detect risk factors. MATERIALS AND METHODS: Between January 2009 and December 2012, the presence of DH was retrospectively recorded in all of the patients who underwent PRFA with multitine expandable electrodes for ablation of nodules in the lower lobe. All nodules were classified into three groups according to the location of the tines after deployment relative to the diaphragm: In group 1, the tines were at a distance of >1 cm from the diaphragm; in group 2, at least one tine was in contact with the diaphragm without perforation; and in group 3, at least one tine was perforating the diaphragm. RESULTS: We recorded 4 cases of DH (3 on the left side, 1 on the right side) in 156 patients (2.3% of procedures). The delay of onset was 7.8 months. DH occurred in groups 2 (n = 1) and 3 (n = 3). Only the 3 cases that occurred on the left side were symptomatic (2 intussusceptions and 1 gastroesophageal reflux) and were surgically repaired. The electrode was positioned in the center of the diaphragm in all cases. CONCLUSION: The central position of the electrode and the contact of at least one tine with the diaphragm after deployment seem to be a risk factor to develop DH.