Near infrared fluorescence imaging of the urethra: a systematic review of the literature

Abstract

Background: Urethral injury is a dreaded complication during laparoscopic, perineal and transanal surgery and is mainly a result of a failed visualization of the urethra. The aim of this systematic review is to provide an overview of the available literature on the near-infrared fluorescence (NIRF) imaging technique using contrast agents for the intra-operative visualization of the urethra.

Material and methods: A systematic review of the literature was conducted including studies on NIRF imaging using contrast agents to visualize the urethra. All studies describing a NIRF imaging technique and demonstrating visual findings of the urethra were included.

Results: Five studies were identified. Four studies examined indocyanine green, one of which also studied the IRDye^® 800BK agent and one examined the CP-IRT dye. All studies showed that the NIRF imaging technique was feasible for an early identification of the urethra. No complications related to NIRF imaging were reported.

Conclusion: We conclude that the use of a NIRF imaging technique is feasible and that it can contribute to prevent iatrogenic injury to the urethra. However, based on the limited available data, no solid conclusion can yet be drawn and further translation to the clinical practice is necessary.

Keywords: Fluorescence imaging; fluorescent dyes; near-infrared; total mesorectal excision; urethral visualization.