Page 51 - Read Online

Page 2 of 10 Fasanella. Mini-invasive Surg 2024;8:5 https://dx.doi.org/10.20517/2574-1225.2023.79

[4]
bilateral renal cell carcinoma (RCC), it rises to 18% . Intraoperative imaging can help perform a cancer-safe
partial nephrectomy by allowing a better localization of the tumor, differentiating it from normal renal
tissue. Imaging is essential to guide the surgeon and provide a complete study of the anatomy of the patient.
To date, conventional two-dimensional (2D) imaging does not allow an optimal evaluation. However,
several technological advances have emerged in recent years. In this narrative review, current and emerging
imaging technologies that can aid in performing a RAPN will be explored.

Literature search strategy
A literature review was performed by analyzing different databases (PubMed, MEDLINE, Research Gate,
and Google Scholar) using the following keywords: “RAPN”, “intraoperative imaging”, “renal cancer”, “3-D
imaging”, “robotic surgery”, “augmented reality”, and “artificial intelligence”. First, articles from the last
decade were selected and evaluated based on their titles and abstracts. Then, some older articles were
included based on their relevance to the topic. All study designs and publication types (reviews, narratives,
or trials) were considered. Finally, the bibliographic references of the various selected articles were also
analyzed.

INTRAOPERATIVE IMAGING TECHNIQUES
Ultrasonography
Intraoperative ultrasound (IOUS) has long been used as a real-time intraoperative imaging technique
during PN, as it helps, with a simple and effective approach, to identify endophytic tumors, evaluate tumor
characteristics, delineate tumor border and renal perfusion during clamping, with a simple and effective
[5-7]
approach . The frequency normally used for the laparoscopic or robotic probe is between 7.5 and 10 Mhz,
[8]
enabling the detection of tumors up to 3-4 mm in diameter . During RAPN, both the assistant and the
surgeon can control the laparoscopic ultrasound probe. Usually, the probe control by the console of the
[5]
surgeon allows for greater autonomy and accuracy .

Doppler mode and contrast-enhanced ultrasound (CEUS) allow for better visualization of renal tumors .
[9]
Hyams et al. presented a prospective evaluation of using the laparoscopic Doppler ultrasound (LDU) to
accelerate hilar dissection during RAPN . Their study demonstrates a reduction in hilar dissection time,
[10]
enhanced detection of accessory vessels (AV) compared to preoperative imaging, adjustments in
operational management based on AV detection, and a change in arterial clamp management.

CEUS is extremely useful in identifying renal tumors. One of the latest generation contrast agents is
SonoVue (Bracco, Milan, Italy), containing stabilized microbubbles of sulfur hexachloride gas .
[11]
Additionally, it appears to be non-nephrotoxic, being eliminated by the lungs, and can be used in patients
with impaired renal function. The recommended dose for renal imaging is 1-2.4 mL and can be repeated if
necessary. The intraoperative CEUS technique uses two types of images: a conventional 2D image
(brightness mode), and a contrast-enhanced mode (a contrast-specific image) that shows the deflection
[8]
produced by the distribution bubble space .

IOUS enables us to characterize an intraparenchymal and complex lesion according to the nephrometric
score , identify the distal portion of a venous thrombus , and perform a more careful evaluation in cases
[12]
[13]
of multifocality and associated renal cysts . It can also help reduce the operative time and the WIT
[14]
[15]
because it improves the delimitation of the mass, especially when there is particularly dense perirenal
adipose tissue . CEUS, by providing real-time imaging of the renal vasculature, can further reduce the
[8]
WIT, favoring the selective clamping process of the arteries that supply blood to the segment of the kidney
containing the tumor . This allows for avoiding global ischemia and further decreasing the loss of
[16]
nephrons.