Utility and challenges of ureteral visualization using a fluorescent ureteral catheter in high risk surgeries for colorectal cancer

Background: Ureteral injury occurs in 0.3-1.5% of colorectal cancer surgeries. Devices to visualize the ureteral course and avoid ureteral injury are required for minimally invasive surgery (MIS). The NIRC™ fluorescent ureteral catheter (FUC) is a versatile ureteral visualization device currently available in Japan that can be used in combination with a variety of laparoscopic and robotic systems. In this study, we examined the outcomes of high-risk patients who underwent colorectal cancer surgery with FUC insertion.

Methods: One hundred forty-one patients who underwent MIS for colorectal cancer and colorectal cancer recurrence at our institute between January 2021 and May 2024 underwent preoperative FUC insertion because of the high risk of ureteral injury and surgical difficulty. For these patients, patient background data and short-term outcomes were examined. The results are expressed as the median and interquartile range.

Results: Age, 70 [60-78]; M:F(n), 84:57; BMI, 22.1 [19.7-24.7]; T4 (TNM classification), 52 cases (36.9%); preoperative intestinal obstruction, 45 cases (31.9%); abscess formation, 30 cases (21%); surgical history, 70 cases (50%); recurrent cancer, 14 cases (9.9%); preoperative chemo-radiotherapy, 28 cases (19.9%); time required for FUC insertion, 12 [9-19] minutes; operation time, 412 [309-552] minutes; blood loss, 10 [5-30] ml; open conversion, 0 cases; postoperative hospitalization, 12 [9-17.5]; circumferential resection margins < 1 mm (rectal surgery), 4/87 cases (4.6%); comorbidities, 0 ureteral injury, 1 urethral injury during FUC insertion (0.7%) and 16 CD Grade 3 or higher cases (11%).

Conclusions: FUC may improve the safety of MIS and reduce blood loss in addition to preventing ureteral injury and is expected to have oncological advantages for ensuring the margin of the tumor without fear of ureteral injury. However, the time required for and complications associated with FUC are challenging. New methods for less invasive and easier ureteral visualization may be needed.