A pilot study of intraoperative localization of peripheral small pulmonary tumors by cone-beam computed tomography: sandwich marking technique.

Background: Intraoperative identification of small pulmonary nodules has been an important technical issue. We aimed to develop a new localization method which is much safer and simple procedure compared with conventional methods. Methods: This was a retrospective study including patients with resected peripheral pulmonary nodules between November 2017 and April 2021 at Teikyo University School of Medicine, and Saitama Cardiovascular and Respiratory Center. All surgical procedure was wedge resection, and the tumor size was equal to or less than 20 mm which were detected by cone-beam computed tomography (CBCT; Philips Allura Xper FD 20, Philips). Some metal clips were put on several places of visceral pleura, where the target lesion was sandwiched by marking clips (sandwich marking technique). CBCT detected both the target lesion and metal clips, and video-assisted thoracoscopic surgery (VATS) was performed. Radiological and pathological findings were analyzed, and the correlation coefficient of tumor size was examined among pre-, intra-, and post-operative tumor sizes. Results: The average age of 90 patients was 65.2 years, and 47 were male (52.2%). All procedure was wedge resection including twelve bi-wedge resections, and one hundred nine peripheral pulmonary lesions were obtained by sandwich marking technique. The detection rate was 100%, and there was no marking-related complication. Conclusions: All small peripheral pulmonary lesions were successfully detected and resected by using CBCT with no marking-related complication. Sandwich marking technique was demonstrated to provide safe, reliable, and simple localization procedure for small peripheral pulmonary lesions.