Near-Infrared Fluorescence-Guided Segmentectomy: Added Benefit of Indocyanine Green Dye Diminishes With Surgeon Experience

Background Near-infrared fluorescence (NIF)-mapping with indocyanine green dye (ICG) facilitates the identification of the intersegmental plane during minimally invasive segmentectomy. Our pilot study showed that ICG is associated with an increase in oncological margin distance from the tumour, greater than the surgeon’s best judgment. We hypothesized that, with greater experience, the surgeon’s judgement will improve, and the benefit of ICG will diminish. Methods This is a phase 2 single-arm trial of patients undergoing robotic-assisted segmentectomy for NSCLC tumours less than 3 cm. After isolating the diseased segment(s), the predicted intersegmental plane (Dp) was identified by the thoracic surgeon. After intravenous ICG injection, the true intersegmental plane (Dt) was revealed using NIF. The primary outcome was the average distance between Dt and Dp (Dt-Dp). Comparisons were performed across 3 temporal tertiles: tertile 1 (t1) comprised of the first 30 participants, and the remaining participants were divided equally for tertiles 2 (t2) and 3 (t3). Kruskal-Wallis test was used to compare differences between tertiles (α = 0.05). Results A total of 190 patients were enrolled from October 2016 to June 2021. The median age was 68 (interquartile range:62-72), and 57.37%(109/190) were women. ICG injection occurred in 60.53%(115/190) of the participants, and intersegmental plane visualization was achieved in 88.70%(102/115). Dt-Dp diminished significantly across tertiles: t1 = 20.65 ± 15.82 mm, t2 = 2.42 ± 15.49 mm, and t3 = 1.36 ± 9.87 mm ( P = 0.0001). Locally estimated scatterplot smoothing revealed that this distance approaches zero as the surgeon performs more cases. Conclusion In our single-surgeon experience with robotic-assisted segmentectomy for NSCLC, the added value of NIF-mapping with ICG diminishes with surgeon experience.