Efficacy of Xenon Light With Indocyanine Green for Intersegmental Visibility in Thoracoscopic Segmentectomy

Background: We previously reported useful methods that can be implemented to identify intersegmental boundary lines (IBLs) by using an intravenous indocyanine green (ICG) fluorescence imaging system (ICG-FS) during a thoracoscopic anatomical segmentectomy (TAS). The aim of this study was to evaluate the recently released third-generation ICG-FS that features an emphasizing xenon-light source for IBL identification. Methods: We prospectively studied cases involving 106 consecutive patients who underwent TAS. Intraoperatively, we used the third-generation ICG-FS, the conventional ICG methods (CIM) emphasizing xenon-light (CIM-X), and the spectra-A method (SAM) emphasizing xenon-light (SAM-X), for IBL identification. Furthermore, 16 of the 106 patients (15%) could be simultaneously evaluated using old-generation ICG-FSs, CIM, and SAM. All images were completely quantified for illuminance and for three colors, red, green, and blue. Results: IBLs were successfully identified in all the patients (100%) with no adverse events. The SAM-X significantly increased the illuminance, especially in the resecting segments, compared to the CIM (39.0 versus 22.2, P < 0.01) and SAM (39.0 versus 29.3, P < 0.01), with enhanced red color compared to the CIM (33.1 versus 21.9, P < 0.01) and SAM (33.1 versus 14.0, P < 0.01). Furthermore, the SAM-X significantly increased the illuminance contrast compared to the CIM-X (34.1 versus 15.3, P < 0.01). Conclusions: The present study suggests that the SAM-X potentially provided images with the highest visibility and colorfulness compared to the older generation ICG-FSs or CIM-X. Secure IBL identification can be more easily and safely performed using the SAM-X.