Near-Infrared fluorescence imaging using indocyanine green (ICG): Emerging applications in pediatric urology

Abstract

Background: Near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) has been recently adopted in pediatric minimally invasive surgery (MIS) in order to improve intra-operative visualization of anatomic structures and facilitate surgery.

Objective: This study aimed to report our preliminary experience using ICG technology in pediatric urology using laparoscopy and robotics.

Study design: ICG technology was adopted in 57 laparoscopic or robotic urological procedures performed in our unit over a 24-month period: 41 (38 laparoscopic - 3 robotic) left varicocele repairs with intra-operative lymphography and 16 renal procedures (12 laparoscopic - 4 robotic) including 9 partial nephrectomies, 3 nephrectomies and 4 renal cyst deroofings.

Results: The ICG solution was injected intravenously in renal procedures or into the testis body in case of varicocele repair. Regarding the timing of the administration, the ICG injection was performed intra-operatively in all cases and allowed the visualization of the anatomic structures in a matter of 30-60 s. The dosage of ICG was 0.3 mg/mL/kg in all indications. All procedures were completed laparoscopically or robotically without conversions. No adverse and allergic reactions to ICG and other complications occurred postoperatively.

Discussion: This paper describes for the first time in pediatric urology that ICG-guided NIRF imaging may be helpful in laparoscopic and robotic procedures. In case of varicocele repair, ICG-enhanced fluorescence allowed to perform a lymphatic-sparing procedure and avoid the risk of postoperative hydrocele. In case of partial nephrectomy, ICG-guided NIRF was helpful to visualize the vascularization of the non-functioning moiety, identify the dissection plane between the two moieties (Fig. 1) and check the perfusion of the residual parenchyma after resection of the non-functioning pole. In case of renal cyst deroofing, ICG-guided NIRF aided to identify the avascular cyst dome and to guide its resection. No real benefits of using ICG-enhanced fluorescence were observed during nephrectomy.

Conclusion: Our preliminary experience confirmed the safety and efficacy of ICG technology in pediatric urology and highlighted its potential advantages as adjunctive surgical technology in patients undergoing laparoscopic or robotic urological procedures. Use of NIRF was also cost-effective as no added costs were required except for the ICG dye (cost 40 eur per bottle). The most common and useful applications in pediatric urology included varicocele repair, partial nephrectomy ad renal cyst deroofing. The main limitation is the specific equipment needed in laparoscopy, that is not available in all centers whereas the robot is equipped with the Firefly® software for NIRF.

Keywords: Children; Fluorescence; Indocyanine green; Laparoscopy; MIS; Robotics; Urology.