Identification of lymphatic pathway involved in the spread of bladder cancer: Evidence obtained from fluorescence navigation with intraoperatively injected indocyanine green.

INTRODUCTION We identify lymphatic vessels draining from the bladder by using fluorescence navigation (FN) system. METHODS In total, 12 candidates for radical cystectomy and pelvic lymph node dissection (PLND) were included in this study. After an indocyanine green (ICG) solution was injected into the bladder during radical cystectomy, lymphatic vessels draining from the bladder were analyzed using a FN system. PLND was based on the lymphatic mapping created from the FN measurements (in vivo probing) in the external iliac, obturator and internal iliac regions; after PLND, the fluorescence of the removed lymph nodes (LNs) was analyzed on the bench (ex vivo probing). RESULTS There were no patients with complications associated with the intravesical ICG injection. A lymphatic pathway along inferior vesical vessels to internal iliac LNs was clearly illustrated in 7 cases. Under in-vivo probing, the fluorescence intensity of internal iliac nodes was greater than that of external iliac or obturator nodes. Under ex-vivo probing, the fluorescence intensity of internal iliac and obturator nodes was greater than that of external iliac nodes. CONCLUSIONS Using an FN system after injecting ICG during a radical cystectomy operation is a safe and rational approach to detecting the lymphatic channel draining from the bladder.