Multispectral Fluorescence Imaging During Robot-assisted Laparoscopic Sentinel Node Biopsy: A First Step Towards a Fluorescence-based Anatomic Roadmap

Abstract

BackgroundDuring (robot-assisted) sentinel node (SN) biopsy procedures, intraoperative fluorescence imaging can be used to enhance radioguided SN excision. For this combined pre- and intraoperative SN identification was realized using the hybrid SN tracer, indocyanine green-99mTc-nanocolloid. Combining this dedicated SN tracer with a lymphangiographic tracer such as fluorescein may further enhance the accuracy of SN biopsy. ObjectiveClinical evaluation of a multispectral fluorescence guided surgery approach using the dedicated SN tracer ICG-99mTc-nanocolloid, the lymphangiographic tracer fluorescein, and a commercially available fluorescence laparoscope. Design, setting, and participantsPilot study in ten patients with prostate cancer. Following ICG-99mTc-nanocolloid administration and preoperative lymphoscintigraphy and single-photon emission computed tomograpy imaging, the number and location of SNs were determined. Fluorescein was injected intraprostatically immediately after the patient was anesthetized. A multispectral fluorescence laparoscope was used intraoperatively to identify both fluorescent signatures. Surgical procedureMultispectral fluorescence imaging during robot-assisted radical prostatectomy with extended pelvic lymph node dissection and SN biopsy. Measurements(1) Number and location of preoperatively identified SNs. (2) Number and location of SNs intraoperatively identified via ICG-99mTc-nanocolloid imaging. (3) Rate of intraoperative lymphatic duct identification via fluorescein imaging. (4) Tumor status of excised (sentinel) lymph node(s). (5) Postoperative complications and follow-up. Results and limitationsNear-infrared fluorescence imaging of ICG-99mTc-nanocolloid visualized 85.3% of the SNs. In 8/10 patients, fluorescein imaging allowed bright and accurate identification of lymphatic ducts, although higher background staining and tracer washout were observed. The main limitation is the small patient population. ConclusionOur findings indicate that a lymphangiographic tracer can provide additional information during SN biopsy based on ICG-99mTc-nanocolloid. The study suggests that multispectral fluorescence image–guided surgery is clinically feasible. Patient summaryWe evaluated the concept of surgical fluorescence guidance using differently colored dyes that visualize complementary features. In the future this concept may provide better guidance towards diseased tissue while sparing healthy tissue, and could thus improve functional and oncologic outcomes.