Rib Fractures after Percutaneous Radiofrequency and Microwave Ablation of Lung Tumors: Incidence and Relevance

Abstract

To retrospectively identify the incidence and probable risk factors for rib fractures after percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) of neoplasms in the lung and to identify complications related to these fractures. Institutional review board approval was obtained for this HIPAA-compliant retrospective study. Study population was 163 patients treated with MWA and/or RFA for 195 lung neoplasms between February 2004 and April 2010. Follow-up computed tomographic images of at least 3 months were retrospectively reviewed by board-certified radiologists to determine the presence of rib fractures. Generalized estimating equations were performed to assess the effect that patient demographics, tumor characteristics, treatment parameters, and ablation zone characteristics had on development of rib fractures. Kaplan-Meier curve was used to estimate patients' probability of rib fracture after ablation as a function of time. Clinical parameters (ie, pain in ribs or chest, organ damage caused by fractured rib) were evaluated for patients with confirmed fracture. Rib fractures in proximity to the ablation zone were found in 13.5% (22 of 163) of patients. Estimated probability of fracture was 9% at 1 year and 22% at 3 years. Women were more likely than were men to develop fracture after ablation (P = .041). Patients with tumors closer to the chest wall were more likely to develop fracture (P = .0009), as were patients with ablation zones that involved visceral pleura (P = .039). No patients with rib fractures that were apparently induced by RFA and MWA had organ injury or damage related to fracture, and 9.1% (2 of 22) of patients reported mild pain. Rib fractures were present in 13.5% of patients after percutaneous RFA and MWA of lung neoplasms. Patients who had ablations performed close to the chest wall should be monitored for rib fractures.