Robotic nephrectomy aided by imaging method

October 1, 2011

Near infrared fluorescence imaging of intravenous indocyanine green during robot-assisted laparoscopic partial nephrectomy can accurately identify the renal vasculature and successfully differentiate tumor from surrounding parenchyma.

Washington-Near infrared fluorescence imaging of intravenous indocyanine green during robot-assisted laparoscopic partial nephrectomy (RALPN) can accurately identify the renal vasculature and successfully differentiate tumor from surrounding parenchyma, say researchers from the University of Rochester Medical Center, Rochester, NY.

First author Scott Tobis, MD, reported results from an initial pilot study utilizing a near infrared fluorescence imaging system that was integrated directly into the da Vinci Si Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA). This technique was evaluated in 11 patients undergoing RALPN, and can be added to existing da Vinci Si surgical systems, according to Dr. Tobis, a resident in urologic surgery at the University of Rochester, working with Dragan Golijanin, MD, and colleagues.

In their study, which was presented at the AUA annual meeting in Washington and subsequently published in the Journal of Urology (2011; 186:47-52), near infrared fluorescence imaging was used for three purposes: to identify tumor from surrounding parenchyma, assist with tumor margin identification, and image the renal vasculature.

"Although the 3-D imaging that is already available in robotic surgery is quite good, we think there's potentially room for improvement when it comes to robotic partial nephrectomy," Dr. Tobis said. "Some of the possibilities with better intraoperative imaging include reducing warm ischemia time, better identification of anomalous renal vessels, selectively causing renal ischemia, and also improving tumor margin identification. This is not only to potentially reduce the positive margin rate but also to reduce the amount of normal renal parenchyma that gets damaged during the surgery."

Indocyanine green (ICG) is a small molecule that, when illuminated at a specific wavelength of light, fluoresces at a slightly longer wavelength-in the near infrared portion of the electromagnetic spectrum. The fluorescence imaging for the da Vinci Si system contains a special light source and camera designed to detect the near infrared fluorescence. Standard white light imaging is also available, "allowing for truly multimodal imaging where the surgeon can seamlessly toggle back and forth between white light and near infrared," according to Dr. Tobis.