Near-infrared fluorescence imaging for intraoperative margin assessment during robot-assisted partial nephrectomy

Objectives To demonstrate how using a standardised dosing strategy of indocyanine green (ICG) dye with near-infrared fluorescence (NIRF) imaging can be used to differentiate renal tumours from normal renal parenchyma during robot-assisted partial nephrectomy (RAPN). Patients and Methods We reviewed a prospectively collected database of 361 consecutive RAPNs using NIRF between June 2011 and March 2018, and determined the rate at which differential fluorescence was achieved. Tumour and kidney fluorescence or afluorescence were recorded intraoperatively and compared to histological results on final pathology. Results Of 330 tumours, after 31 exclusions for nonvisible tumours due to adherent fat, completely intrarenal location or for incomplete data, 288 (87.3%) successfully exhibited differential fluorescence. Among the predominant histologies, 249 of 277 (89.9%) renal cell carcinomas did not fluoresce, as well as 23 of 32 (71.9%) oncocytomas. Real-time gross assessment of resection margin for fluorescence yielded a positive margin rate on final pathology of 0.30%. Conclusion When administered with a standardised ICG-dosing strategy, NIRF successfully achieved differential fluorescence in a large majority of tumours during RAPN with an exceedingly low positive margin rate.