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Purpose The purpose of this study was to evaluate the feasibility and safety of transbronchial cryoablation with a novel flexible cryoprobe using nitrogen as the refrigerant in an in vivo porcine model of lung parenchyma. Materials and methods A novel flexible cryoprobe using nitrogen as the refrigerant was used for transbronchial cryoablation of lung parenchyma in six normal female pigs. The cryoprobe was delivered to the distal bronchus in the bilateral porcine lungs via the bronchoscopic working channel under virtual bronchoscopy guidance. The position was confirmed with real-time computed tomography (CT). The whole procedure included two freeze-thaw cycles (15 min and 2 min, respectively). CT images were obtained during cryoablation and at 24 h, one week, two weeks and four weeks after the treatment to assess the effectiveness and safety of the procedure. Ablation zone tissue samples were obtained at 24 h and four weeks after the cryoablation for further histopathological analysis. Results All ablation procedures (12/12; 100%) were performed successfully. No major complications occurred during the procedure or the observation period. The ablation zones were clearly depicted on CT with a maximal ablation zone volume at 24 h (21.88 ± 12.61 [SD] cm3) compared to 3.64 ± 2.06 (SD) cm3 and 10.73 ± 3.84 (SD) cm3 at the end of the 1st and 2nd freeze-thaw cycles, respectively (P Conclusion The novel flexible bronchoscopy-guided cryoablation is a feasible, safe and effective modality in an in vivo porcine model of peripheral normal lung parenchyma, suggesting potential capabilities for the treatment of peripheral lung cancer in humans.

Background Accurate preoperative localization of small pulmonary nodules facilitates the rapid and precise video-assisted thoracoscopic surgery (VATS). This study aims to evaluate the feasibility, safety, and efficacy of navigation bronchoscopy-guided pulmonary microcoil placement for preoperative pulmonary nodule localization. Methods Twelve lung lesions were simulated by mixing lipiodol in three porcine models. After 1 week, two microcoils per lesion were deployed under bronchoscopic guidance. Computed tomography scans were then performed 1 day, 1 week, 2 weeks, and 4 weeks after the deployment to assess the position of the microcoils relative to the lesions. Surgical resection of the simulated lesions was performed under fluoroscopy 5 weeks after the deployment and the accuracy, stability, and associated complications of the microcoil localization were evaluated. Following this, an exploratory clinical study was conducted on three patients with pure ground-glass pulmonary nodules. Results The mean diameter of the twelve simulated lung lesions was 9.55±2.36 mm, and the mean distance from the pleura to the lesions was 8.29±2.99 mm. Twenty-four pulmonary microcoils were implanted in the bronchi surrounding the lesions. Four weeks later, the mean distance between the microcoils and the center of the lesions was 16.12±8.97 mm and the average migration of the microcoils relative to the baseline position (1 day after implantation) was 3.48±4.56 mm. All microcoils and target lesions were successfully resected in both the animal experiment and clinical study and no complications, such as pneumothorax, were observed during marker implantation or postoperative follow-up. Conclusions The preoperative localization of pulmonary nodules by navigation bronchoscopy-guided microcoil placement is a safe, stable, and effective technique with minimal complication risk. This procedure can assist subsequent thoracoscopic resection.

Primary tracheal leiomyoma is exceedingly rare and recommended management has not been defined yet. Surgical management has been considered to be the standard treatment historically. Bronchoscopic intervention may be an ideal alternative for patients who refuse or are not fit for surgery. We report the first bronchoscopic submucosal dissection using an innovative water-jet Hybrid Knife performed on a patient with recurrent primary tracheal leiomyoma.