Robot-Assisted Surgery Performed Using a Fluorescent Ureteral Catheter for Locally Advanced Sigmoid Colon Cancer: A Case Report

In recent years, robotic surgery for colorectal cancer has increased and is now being performed even for locally advanced colorectal cancers. However, due to adhesions and tissue fibrosis caused by infiltration and inflammation, the risk of misidentification during dissection is high. In robotic surgery, which lacks tactile feedback, particular caution is required to avoid injuries such as ureteral damage. Navigation surgery using fluorescent ureteral catheters that emit fluorescence upon near-infrared light irradiation has attracted attention. In this report, we describe a case where a safe robotic sigmoidectomy was successfully performed using fluorescent ureteral catheters. A 65-year-old man visited our hospital with a chief complaint of abdominal pain and was diagnosed with sigmoid colon cancer infiltrating the pelvic wall (cT4N1M0). The tumor was infiltrating the pelvic wall, and it was expected that establishing a safe dissection plane would be challenging with upfront surgery. Therefore, he first underwent three courses of neoadjuvant chemotherapy, which resulted in tumor shrinkage. Although no invasion of the tumor into the ureter was observed, the ureter's course was in close proximity, raising concerns about intraoperative injury. Consequently, the surgery was performed with intraoperative navigation using a fluorescent ureteral stent, which was visualized intraoperatively. The operation was successfully performed by maintaining an appropriate dissection layer, ensuring safety. The postoperative pathological examination confirmed that the surgical margins were negative, and two years have elapsed since the surgery, no recurrence has been observed. In this way, fluorescent ureteral catheters facilitate the visualization of the appropriate dissection layer, ultimately helping to prevent injury to both the urinary tract and blood vessels. They are particularly useful for ensuring safe surgery when tumors are huge or when preoperative adjuvant therapies have been administered, resulting in tissue hypertrophy and fibrosis. Under such conditions, these stents are considered to significantly contribute to the safety of the procedure.