Fluorescence-Guided Bladder and Ureter Visualization in Benign Robotic Gynecologic Surgery: A Series of Five Cases

Cases 1 and 2: bladder demarcation using intravesical ICG Two patients undergoing robotic hysterectomy for benign indications had a history of prior cesarean sections. To facilitate dissection of the vesicouterine plane, intravesical ICG was administered (25 mg diluted in 200 mL of normal saline and sterile water) through a Foley catheter, which was temporarily clamped for five and 10 minutes, respectively. Case 1 The patient was a 48-year-old woman with a history of two cesarean deliveries who underwent robotic hysterectomy with bilateral salpingectomy for multiple uterine fibroids associated with abnormal uterine bleeding. The appearance of the vesicouterine dissection and the subsequent bladder fluorescence pattern are shown in Figure 1 . Case 2 The patient was a 41-year-old woman with a history of one cesarean delivery who underwent robotic hysterectomy with bilateral salpingectomy for grade 3 uterine prolapse. The intraoperative view before fluorescence activation and the bladder fluorescence obtained after ICG instillation are presented in Figure  2 . Both cases demonstrated inconsistent and patchy fluorescence, with partial visualization limited to non-scarred areas of the bladder wall. Fluorescence was poor in regions with dense fibrosis. Despite the suboptimal imaging, both surgeries were completed robotically without injury to the bladder or ureters. Cases 3 and 4: ureter visualization using retrograde ICG Two patients with advanced endometriosis underwent robotic surgery. Due to significant adhesions, ureteric identification was expected to be challenging. Cystoscopic retrograde instillation of ICG (12.5 mg diluted in 5 mL normal saline) was performed into each ureter. Case 3 The patient was a 43-year-old woman with deep infiltrating endometriosis who underwent a robotic hysterectomy with bilateral salpingo-oophorectomy. Preoperative MRI revealed extensive deep pelvic endometrial implants and demonstrated the right ureter in close proximity to the posterior uterine wall. Intraoperative findings and ureteral fluorescence obtained during dissection are shown in Figures 3 - 5 . Case 4 A 29-year-old patient with stage 3 endometriosis underwent robotic endometriosis excision. Preoperative MRI demonstrated a multiloculated cystic lesion in the right adnexa consistent with a tubo-ovarian endometrioma, a unilocular left ovarian endometrioma, and kissing ovaries. The intraoperative white-light and Firefly near-infrared fluorescence views used for ureteral identification throughout the procedure are presented in Figures 6 - 8 . Both procedures were completed without complications. Case 5: ureter visualization with ICG in a patient with an ectopic kidney A 50-year-old patient was scheduled for robotic hysterectomy with bilateral salpingo-oophorectomy due to symptomatic adenomyosis and chronic pelvic pain. Preoperative MRI demonstrated posterior wall adenomyosis, multiple intramural fibroids, a right ovarian endometriotic cyst, and a left hydrosalpinx. An additional significant finding was the presence of an ectopic left kidney, located inferior and medial to the right kidney. The ectopic kidney showed no hydronephrosis. Ureteral anatomy was presumed to be atypical due to the ectopic renal position, raising concern for potential ureteral vulnerability during pelvic dissection. Intraoperative ICG near-infrared fluorescence imaging confirmed the altered course of the ureters at the beginning of surgery (Figure 9A - 9B ), assisted in entering distorted posterior planes (Figure 10A - 10B ), and verified bilateral ureteral integrity at the end of the procedure (Figure 11A - 11B ).

Near-infrared fluorescence with indocyanine green (ICG) is well established in gynecologic oncology, especially for sentinel lymph node mapping, but its use in benign gynecology is still evolving [ 1 ]. As minimally invasive approaches become routine, surgeons increasingly explore ICG to help identify structures such as the bladder and ureters, assess perfusion, and guide dissection [ 2 ]. Retrograde ureteral instillation introduces ICG directly into the ureteral lumen, where the dye remains intraluminal due to the impermeability of the urothelium. Under near-infrared imaging, this produces a clear fluorescent outline of the ureter for accurate anatomical localization. Intravesical instillation similarly confines ICG to the bladder lumen, coating the mucosal surface and generating uniform fluorescence that delineates bladder contours. This becomes particularly relevant in patients with distorted pelvic anatomy, most commonly due to previous cesarean deliveries or deep infiltrating endometriosis, where the risk of urinary tract injury is noticeably higher. Ureteral injury is a recognized complication during complex gynecologic procedures, particularly in patients with deep endometriosis or extensive adhesions. Robotic-assisted ureterolysis using ICG has been reported as a feasible technique to improve intraoperative ureter visualization [ 3 ]. Rare anatomic variants, such as ectopic kidneys with atypical ureteral pathways, further increase the challenge of pelvic dissection and highlight the importance of reliable intraoperative visualization strategies. Subsequent studies have applied ICG-guided ureterolysis in complex laparoscopic or robotic gynecologic surgeries, and systematic intraureteral ICG injection has been proposed as a reliable method to reduce the risk of injury [ 4 , 5 ]. Despite growing interest, protocols for ICG use in benign gynecologic surgery remain inconsistent. Most of the available literature consists of small case reports or heterogeneous case series, which describe institution-specific techniques rather than systematically evaluated protocols. In this case series, we present two patients who received intravesical ICG for bladder demarcation during robotic hysterectomy and three patients who underwent retrograde ureteric ICG instillation for endometriosis surgery using the Da Vinci Xi Firefly system (Intuitive Surgical, Sunnyvale, California, United States), an imaging mode on the Da Vinci robotic system that detects ICG within tissues or lumens. The goal is to compare the reliability and practicality of each technique in a benign gynecology setting.

This case series highlights the difference in reliability between intravesical and retrograde ICG application in benign gynecologic robotic surgery. Intravesical ICG showed limited and inconsistent uptake in both patients with prior cesarean deliveries. The most likely explanation is that cesarean-related fibrosis restricts ICG diffusion through the bladder mucosa and reduces near-infrared penetration, resulting in uneven fluorescence. Other authors have noted similar challenges, particularly in scarred anterior compartments where visualization is clinically most important [ 6 ]. In contrast, retrograde ICG instillation provided uniform and strong fluorescence in both patients undergoing endometriosis surgery. Because the dye directly contacts the ureteral mucosa, uptake is more predictable, and the linear anatomy of the ureter produces a continuous signal. This significantly improves safety during ureterolysis, especially when fibrosis has distorted normal landmarks. The findings align with existing literature demonstrating the effectiveness of ureteric ICG in complex benign pelvic surgery [ 1 , 7 ]. The fifth case illustrated how congenital renal anomalies can alter ureteral pathways and increase the complexity of pelvic surgery. In this patient, the ectopic left kidney resulted in both ureters originating on the right side of the pelvis, raising concern for potential misidentification during dissection. Intraoperative ICG fluorescence allowed the clear visualization of the atypical ureteral course at the beginning of the procedure and confirmed bilateral ureteral continuity into the bladder at the end of the surgery. This case highlights the utility of fluorescence imaging not only in diseased or fibrotic retroperitoneal spaces but also in patients with unusual anatomic configurations, consistent with previous reports describing the use of ICG to localize ureters in cases of crossed renal ectopia [ 8 ]. For trainees, fluorescence offers a helpful visual guide during robotic surgery, where tactile feedback is limited. However, the current lack of standardized dosing, dilution, and technique, especially for intravesical use, remains a barrier to broader adoption.

ICG fluorescence is a valuable adjunct in benign robotic gynecologic surgery. Retrograde ureteric ICG provides dependable visualization and is particularly useful in endometriosis cases requiring ureterolysis. The presence of unusual anatomic variants, such as ectopic renal positioning, further reinforces the need for dependable ureteral visualization tools to ensure safe dissection during complex gynecologic surgery. On the other hand, intravesical ICG for bladder demarcation shows inconsistent results in patients with previous cesareans, limiting its usefulness. Further evaluation in larger prospective studies is needed to clarify optimal protocols and define its role in benign gynecologic surgery.