Elsevier

European Urology Focus

Volume 6, Issue 3, 15 May 2020, Pages 505-512
European Urology Focus

Review – Kidney Cancer
Near-infrared Fluorescence Imaging with Indocyanine Green in Robot-assisted Partial Nephrectomy: Pooled Analysis of Comparative Studies

https://doi.org/10.1016/j.euf.2019.03.005Get rights and content

Abstract

Context

The use of near-infrared fluorescence (NIRF) imaging was described to facilitate selective clamping during robot-assisted partial nephrectomy (RAPN).

Objective

To perform a systematic review and cumulative analysis of available studies comparing the outcomes of RAPN with or without use of this technology (NIRF).

Evidence acquisition

A systematic review of the literature was performed to identify relevant studies up to December 2018 through PubMed and EMBASE databases. A meta-analysis was conducted with the RevMan 5.3 software.

Evidence synthesis

Six comparative studies were identified. Overall, 369 cases were included for the analysis (171 NIRF-RAPN and 198 standard RAPN). No significant difference was identified between groups in baseline characteristics, operating time, and estimated blood loss; however, a shorter clamping time was recorded for the NIRF-RAPN group. Functional outcomes revealed higher overall estimated glomerular filtration rate (eGFR) values in the NIRF-RAPN group at short-term (1–3 mo) postoperative follow-up (weighted mean difference [WMD]: 9.26 ml/min; 95% confidence interval [CI]: 6.46, 12.06; p < 0.001). In two studies, a renal scan-based assessment of split eGFR was available, and pooled analysis revealed higher split eGFR for NIRF-RAPN (WMD: 7.91 ml/min; 95% CI: 4.26, 11.56; p < 0.001), and lower Δ % between preoperative and 1-mo eGFR (WMD: −7.84%; 95% CI: −8.85, −6.83; p < 0.00001).

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. 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 undergoing RAPN, especially in the long term.

Patient summary

We assessed the outcomes of robot-assisted partial nephrectomy (RAPN) performed with or without the use of near-infrared fluorescence (NIRF) imaging. NIRF-RAPN appeared to be a safe procedure with potential better short-term functional outcomes.

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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