Review – Kidney CancerNear-infrared Fluorescence Imaging with Indocyanine Green in Robot-assisted Partial Nephrectomy: Pooled Analysis of Comparative Studies
Introduction
Indocyanine green (ICG; IC-Green; Akorn, Lake Forest, IL, USA) is a safe Food and Drug Administration (FDA)-approved fluorescent dye, which is widely used in medical specialties to identify vascular structures and nodal drain [1], [2]. Over the past 5 yr, near-infrared fluorescence (NIRF) using ICG has emerged as a safe technology to better visualize anatomical structures during surgery [3]. The integration of this tool into the da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) allowed robotic surgeons to explore its application for a wide range of robotic urologic procedures [4]. More specifically, the use of NIRF imaging was described to aid during minimally invasive partial nephrectomy (PN) [5], [6]. In this setting, the technology was shown to differentiate normally perfused (healthy) renal parenchyma from the tumoral lesion, allowing easier scoring of the resection margin [7]. More recently, authors have reported the use of ICG-NIRF during robotic resection of totally endophytic renal masses [8].
The role and impact of warm ischemia on functional outcomes of PN are still debated. Our clinical practice has been driven by the long-standing dogma to limit ischemia time to under 30 min [9], [10], [11], which was then reduced to 25 min [12], eventually culminating in the principle of zero ischemia [13]. Several different surgical strategies have been explored to minimize ischemia-related damage, and techniques such as cold ischemia, selective clamping, early unclamping, and zero ischemia have been investigated to achieve this purpose [14].
Most studies on the use of NIRF during robotic urologic surgery focused on the use of this tool to facilitate selective artery clamping during robotic-assisted partial nephrectomy (RAPN). In this work, we performed a systematic review and pooled analysis of the available studies comparing the outcomes of RAPN with or without the use of ICG-NIRF.
Section snippets
Literature search
After establishing a study protocol, a research question was formulated according to the PICO model (P = patients with renal mass; I = NIRF-RAPN [with selective clamping]; C = standard RAPN [with main artery clamping]; O = surgical outcomes). A systematic review of the literature was performed using PubMed and EMBASE to identify relevant studies up to December 2018. The research was made adopting a free text protocol. The following search terms were used: “indocyanine green,” “near infrared
Description of included studies and quality assessment
Six comparative studies (all retrospective cohort studies, including four with match-paired analysis) published between 2012 and 2018 were identified [20], [21], [22], [23], [24], [25] (Fig. 1). The characteristics of included studies are summarized in Table 1. Study quality was 3 for all studies. Owing to small number of studies, visual assessment was unlikely to be accurate, but no obvious publication bias was observed.
Demographics and clinical characteristics
Overall, 369 cases were included for the analysis (171 NIRF-RAPN and 198
Discussion
This is the first meta-analysis of studies comparing RAPN performed with or without the use of NIRF-ICG selective clamping. This analysis on a pooled sample of 369 patients (171 NIRF-RAPN and 198 standard-RAPN) can be cue for further studies and it gives a picture of the current evidence on this topic. Overall, our findings show that the use of NIRF can aid the surgeon in a selective clamping approach, possibly leading to a lower decline of renal function in the short term, compared with a
Conclusions
Current evidence regarding the use of NIRF-guided selective clamping during RAPN is based on a limited number of studies from high-volume institutions. These studies are mostly retrospective, of medium quality, with a limited sample size and short follow-up. Notwithstanding these limitations, NIRF-RAPN can be safely performed, and it might offer better short-term renal functional outcomes. It remains to be determined whether this can ultimately translate into a clinical benefit for patients
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2022, Asian Journal of UrologyCitation Excerpt :A pooled analysis of six comparative studies demonstrated that NIR- or ICG-guided RAPN was associated with shorter WIT; however, there was no significant difference regarding operative time, estimated blood loss, and postoperative complications. Furthermore, this meta-analysis confirmed significantly higher eGFR preservation for ICG-guided RAPN at short-term follow-up (1–3 months) [71]. Moreover, ICG can be used for the differentiation between benign and malignant renal tissues as ICG binds to a transmembrane protein known as bilitranslocase that allows ICG to perfuse intracellularly and accumulate in the proximal convoluted tubules without accumulation in the malignant renal tissues (as cancerous renal cells do not express bilitranslocase).
Outcomes of robot-assisted partial nephrectomy for completely endophytic renal tumors: A multicenter analysis
2021, European Journal of Surgical OncologyCitation Excerpt :Intraoperative use of ultrasound probe remained standard option for totally endophytic tumors, in order to score the resection area on kidney mass [23]. Indeed, near-infrared fluorescence imaging has been mainly used to facilitate selective clamping during RAPN [24]. Recently, Simone et al. [25] described a technique to simplify off-clamp RAPN in completely endophytic masses based on ICG-lipodol mixture selective tumor marking.
Robotic Partial Nephrectomy: Update on Techniques
2021, Urologic Clinics of North AmericaThe Role of Intraoperative Indocyanine Green in Robot-assisted Partial Nephrectomy: Results from a Large, Multi-institutional Series
2020, European UrologyCitation Excerpt :ICG is a green fluorescent dye that can be visualized at NIRF and, thus, functions as an intraoperative tracer [8]. Studies suggest that the use of NIRF-ICG could help the surgeon in a full or selective clamping approach and in the delineation of surgical margins, possibly leading to better preservation of renal function in the short term, compared with a standard whole-clamping RAPN [9–11]. Following intravenous injection, ICG binds rapidly to plasma proteins of renal parenchymal cells, especially lipoproteins.