Localizing small lung lesions in video-assisted thoracoscopic surgery via radiofrequency identification marking

Abstract

Background: To facilitate accurate localization of small lung lesions in thoracoscopic surgery, we employed a micro-radiofrequency identification tag designed to be delivered through the 2-mm working channel of a flexible bronchoscope. This report presents the results of preclinical studies of our novel localizing technique in a canine model. Methods: To evaluate functional placement, three types of tags [Group A, tag alone (n = 18); Group B, tag + resin anchor (n = 15); and Group C, tag + NiTi coil anchor (n = 15)] were bronchoscopically placed in subpleural areas and subsegmental bronchi via our new delivery device; tags were examined radiographically on days 0–7 and day 14. In addition, eight tags, which were placed at a mean depth of 13.3 mm (range 9–15.7 mm) from visceral pleura in bronchi with a mean diameter of 1.46 mm (range 0.9–2.3 mm), were recovered by partial lung resection under video-assisted thoracoscopic surgery using a 13.56-MHz wand-shaped probe with a 30-mm communication range. Results: Peripheral airway placement: Group C had a significantly higher retention rate than the other two groups (retention rate at day 14: Group A, 11.1 %; Group B, 26.7 %; Group C, 100.0 %; P < 0.0001). Central airway placement: Overall retention rate was 73.3 % in Group C, and placement was possible in bronchi of up to 3.3 mm in diameter. Outcomes of partial resection: Tag recovery rate was 100 %, mean time required for tag detection was 10.8 s (range 8–15 s), and mean surgical margin from the delivered tag was 9.13 mm (range 6–13 mm). Conclusion: Radiofrequency identification marking enabled accurate localization with depth, which could ensure effective deep resection margins.