Robot-assisted and laparoscopic partial nephrectomy with near infrared fluorescence imaging

Recent literature has focused on the importance of maximal nephron preservation during partial nephrectomy to avoid complications associated with chronic renal insufficiency. Accurate differentiation of tumor from normal surrounding parenchyma is critical to ensure excessive normal renal tissue is not made ischemic or excised along with the tumor. The feasibility of a novel intraoperative imaging technique to differentiate tumor from surrounding parenchyma during laparoscopic and robot-assisted partial nephrectomy was evaluated.

Patients who were scheduled to undergo laparoscopic or robot-assisted partial nephrectomy were recruited from April 2009 to July 2010. The Endoscopic SPY Imaging System was used as an adjunct to intraoperative imaging in all cases. Patients received intravenous injections of indocyanine green (ICG), which was visualized intraoperatively with the near infrared fluorescence (NIRF) imaging capability of the SPY scope. The degree of tumor fluorescence compared with surrounding renal parenchyma was qualitatively assessed before tumor resection, and partial nephrectomy was then performed with standard techniques while intermittently using NIRF imaging.

Nineteen patients underwent intravenous administration of ICG followed by NIRF during partial nephrectomy. Average tumor size was 3.0 cm (range 0.8-5.9 cm). Thirteen masses were malignant on final pathology results, and all of these were seen to be hypofluorescent compared with surrounding renal parenchyma during intraoperative imaging. The imaging behavior of benign tumors ranged from isofluorescent to hyperfluorescent compared with normal parenchyma. No complications were associated with ICG injection.

NIRF imaging after intravenous ICG administration may be a useful intraoperative imaging tool to differentiate malignant tumors from normal renal parenchyma during laparoscopic and robot-assisted partial nephrectomy. Advanced intraoperative imaging techniques such as this one may become increasingly helpful as more complicated tumors are resected with minimally invasive approaches.