Indocyanine Green Ureteral Mapping in Complex Pelvic Surgery

INTRODUCTION: Iatrogenic injury to the urinary tract is a known complication of gynecologic surgery, with reported rates for ureteral injury up to 1.5%. [1] This incidence increases with surgical complexity and varies based on surgical approaches. Risk factors include prior surgery, malignancy, infection, enlarged uterus, endometriosis, and pelvic organ prolapse. Laparoscopic and robotic-assisted hysterectomies have up to a 6% risk, and reconstructive pelvic surgery has up to an 11% risk of intraoperative ureteral injury. [1] Prevention of iatrogenic ureteral injury is dependent on optimizing ureteral visualization throughout its pelvic course. Routine prophylactic ureteral stents are not proven to reduce the risk of intraoperative ureteral injury, and their utility is limited in robotic-assisted surgery due to the lack of tactile feedback. [2] Visual feedback using retrograde ureteral indocyanine green (ICG) instillation and near-infrared (NIR) fluorescence has shown to be a safe, effective, and reproducible option for ureteral identification in robotic-assisted complex pelvic surgeries. [3] OBJECTIVE: The purpose of this video is to discuss risks for intraoperative ureteral injury, explain our technique for ICG ureteral mapping, and review pelvic anatomic relationships to the ureter during complex pelvic surgeries. METHODS: We present robotic surgical cases where retrograde ureteral instillation of ICG and NIR fluorescence was utilized for intraoperative ureteral mapping. Each case starts with ICG instillation, using a 30-degree cystoscope and a 6 French graduated open-ended ureteral catheter. One 25-mg ICG vial was mixed with 10 mL of sterile water to form a 10-mL solution, allotting 5 mL for each ureter. Ureteral catheters were advanced to 20 cm, and the ICG solution was injected as they were retracted and removed. A Foley catheter was placed and the robotic portion of the case was started immediately following. The first case is a robotic hysterectomy with leiomyomata, adhesive tissue, and endometriosis. The second case is a robotic hysterectomy with high uterosacral ligament suspension (USLS). The third is a robotic sacrocolpopexy for post-hysterectomy vaginal prolapse. RESULTS: Cases ranged from 116 to 183 minutes. ICG fluorescence was visible throughout the duration of all cases and allowed for visualization of the ureter at key steps in each procedure. All patients were discharged home on the day of surgery without complications. Methods to avoid ureteral injury are highlighted in the video, including cephalad traction of the uterine fundus, dissection of the bladder beyond the anterior fornix, and skeletonization of the uterine vessels to displace the ureter laterally. In a robotic sacrocolpopexy, ICG delineated the ureters during dissection at the sacrum and vaginal cuff. ICG optimized ureterolysis in cases with adhesive disease and distorted anatomy. CONCLUSIONS: ICG with NIR fluorescence is a useful tool for ureteral mapping during complex robotic pelvic and reconstructive surgeries. Knowledge of the course of the ureter and its anatomic relationships is critical prior to performing complex pelvic surgery. More data with larger prospective studies is needed utilizing ICG ureteral mapping to determine if it significantly reduces the risk of ureteral injury in complex gynecology and urogynecology cases.