Assessing the Feasibility of Using Methylene Blue in Identifying Ureters During Colorectal Surgery

This study will assess whether methylene blue fluorescence imaging can help surgeons identify the ureters during colorectal surgery. Methylene blue, given through a vein during the operation, is taken up and excreted by the kidneys, allowing the ureters to appear under a special fluorescence camera system. The study will include adults undergoing open, laparoscopic, or robotic colorectal surgery at Prince of Wales Hospital. The surgeons will compare ureter visibility using standard white light with visibility using fluorescence imaging at different stages of the operation. The study will also assess the best dose of methylene blue, the additional time required, the ease of using the imaging system, and whether the imaging findings affect the surgical plan. The study's hypothesis is that methylene blue fluorescence imaging will make it easier or faster to identify the ureters than white light alone. The technique will be considered feasible if it is helpful in at least 20% of operations-for example, by identifying a ureter earlier or identifying it when it cannot be seen under white light. The findings will help determine whether a larger future study should be conducted.