Lung Ablation Research Articles

Percutaneous Radiofrequency Lung Ablation Combined with Transbronchial Saline Injection: An Experimental Study in Swine

To evaluate the efficacy of radiofrequency lung ablation with transbronchial saline injection. The bilateral lungs of eight living swine were used. A 13-gauge bone biopsy needle was inserted percutaneously into the lung, and 1 ml of muscle paste was injected to create a tumor mimic. In total, 21 nodules were ablated. In the saline injection group (group A), radiofrequency ablation (RFA) was performed for 11 nodules after transbronchial saline injection under balloon occlusion with a 2-cm active single internally cooled electrode. In the control group (group B), conventional RFA was performed for 10 nodules as a control. The infused saline liquid showed a wedge-shaped and homogeneous distribution surrounding a tumor mimic. All 21 RFAs were successfully completed. The total ablation time was significantly longer (13.4 +/- 2.8 min vs. 8.9 +/- 3.5 min; P = 0.0061) and the tissue impedance was significantly lower in group A compared with group B (73.1 +/- 8.8 Omega vs. 100.6 +/- 16.6 Omega; P = 0.0002). The temperature of the ablated area was not significantly different (69.4 +/- 9.1 degrees C vs. 66.0 +/- 7.9 degrees C; P = 0.4038). There was no significant difference of tumor mimic volume (769 +/- 343 mm(3) vs. 625 +/- 191 mm(3); P = 0.2783). The volume of the coagulated area was significantly larger in group A than in group B (3886 +/- 1247 mm(3) vs. 2375 +/- 1395 mm(3); P = 0.0221). Percutaneous radiofrequency lung ablation combined with transbronchial saline injection can create an extended area of ablation.

Phrenic Nerve Injury Resulting from Percutaneous Ablation of Lung Malignancy

The objective of our study was to illustrate the potential for phrenic nerve injury during percutaneous lung ablation, to discuss the importance of this complication, and to review the expected location of the phrenic nerve on chest CT. Knowledge of the expected location of the phrenic nerve-a structure that is usually not visible on imaging but is important-is essential for avoiding injury to the nerve during pulmonary ablation.

Protection of the Mediastinum and Chest Wall with an Artificial Pneumothorax during Lung Ablations

The objective in creating an artificial pneumothorax during lung ablation is to develop a working space in the thorax sufficient to displace the target lung lesion from adjacent vulnerable mediastinal or chest wall structures. Attempts to induce a protective pneumothorax with the use of spring-loaded needles were successful in four of six patients, permitting development of safe "windows" for ablation. These pneumothoraces were induced by the introduction of a needle with a spring-loaded, blunt-tipped obturator into the pleural space, followed by injection of room air. Pleural adhesions related to previous interventions may interfere with creation of a pneumothorax. Use of this technique could extend the utility of ablative therapies for lesions adjacent to the mediastinum and chest wall.

Five-year Survival following Radiofrequency Ablation of Small, Solitary, Hepatic Colorectal Metastases

Radiofrequency (RF) ablation is an increasingly accepted treatment for nonsurgical candidates with a limited number of colorectal hepatic metastases. RF ablation is most effective in tumors smaller than 4.0 cm. This report describes 5-year survival in patients with single tumors with a maximum diameter of 4 cm. Forty of 291 patients (14%; 24 men, 16 women; mean age, 67 years; age range, 34-86 y) with no or treated extrahepatic disease were identified who were not candidates for resection and who had a minimum follow-up of 6 months. Sixteen had undergone hepatic resection and two had undergone lung resection and lung ablation. Thirty-two (80%) received chemotherapy. Thirty-five were treated under general anesthesia and five under conscious sedation. Our standard ablation protocol used internally water-cooled electrodes introduced percutaneously with ultrasonography and computed tomography guidance and monitoring. Follow-up data were obtained from primary care physicians or oncologists. Mean tumor diameter was 2.3 cm (range, 0.8-4.0 cm). There were two successfully treated systemic complications: a chest infection and an exacerbation of asthma. There were no local complications. Mean follow-up was 38 months (range, 6-132 months). The median survival duration and 1-, 3-, and 5-year survival rates were 59 months and 97%, 84%, 40%, respectively, after ablation; and 63 months, 100%, 88%, and 54%, respectively, from the diagnosis of liver metastases. History of liver resection did not impact survival. RF ablation of solitary liver metastases 4 cm or smaller can be performed with minimal morbidity and results in excellent long-term survival, approaching that of surgical resection, even in patients who are not surgical candidates.

Complications of Ablative Therapies in Lung Cancer

Two cases of complications secondary to the use of microwave ablation (MWA) in non–small-cell lung cancer (NSCLC) are discussed herein. The first case involves a 62-year-old man with stage IB NSCLC who declined surgery and pursued MWA. Within 7 months, he had residual disease at the MWA treatment site, and surgery was performed. The patient was found to have pleural and chest wall involvement, making complete resection impossible. The second case involves an 86-year-old woman with a second local recurrence of NSCLC and previous treatment including surgery and chemoradiation therapy. She was initially a surgical candidate but declined surgery and pursued MWA. Within 6 months, she had residual disease at the MWA treatment site. A second MWA was performed, and she developed a large cavitary abscess at the MWA site and had subsequent clinical decline. Less invasive ablation therapies and stereotactic radiosurgery are being developed for patients with inoperable lung cancer. Because these modalities have recently been developed, trials that clearly show efficacy and survival benefit are yet to be completed. Ablation procedures can result in complications, including residual disease and cavitary lesions susceptible to infection. These cases highlight the caution that should still be observed when recommending lung ablation strategies and the importance of selecting appropriate patients.