Despite technical improvements introduced by robotic surgery, the management of complex renal tumours (PADUA score >10) still remains challenging, especially for endophytic masses. In this setting the available technologies for intraoperative imaging (like Ultrasound [US]) may have some limitations in identifying all the intrarenal structures. In order to overcome these limitations, we developed our 3D static and elastic Augmented Reality (AR) system from hyper accuracy 3D models (HA3DTM) and we compared this technology with US in driving the surgeon during the two main steps of RAPN: tumor resection and parenchymal suture.
We include 91 patients who underwent RAPN for complex renal tumours; 48 with 3D-AR guidance and 43 with 2D US guidance; from July 2017 to May 2019. In patients who underwent 3D-AR-RAPN, virtual image overlapping guided the surgeon during resection and suture phases. In the 2D-US group interventions were driven by the US only. Patient characteristics were tested using the Fisher’s exact test and the Mann-Whitney test. Intraoperative, postoperative, and surgical outcomes were collected and analysed. Statistical significance was set at p<0.05.
The use of 3D AR guidance makes it possible to correctly identify the lesion and intraparenchymal structures with a more accurate 3D perception of the location and of the nature of the different structures relative to the standard 2D-US guidance. This translates to a lower rate of global ischemia (45.8% in 3D group vs. 69.7% in US group; p=0.03), higher rate of enucleation (62.5% vs. 37.5% in 3D and US group respectively; p=0.02) and lower rate of collecting system violation (10.4% vs. 45.5%; p= 0.003). Postoperatively 3D AR guidance use correlates to a low risk of surgery related complications in 3D AR groups and a lower drop in estimated renal plasma flow (ERPF) at renal scan at three months of follow-up (-12.38 in 3D group vs. -18.14 in US group; p=0.01).
HA3DTM models which overlap in vivo anatomy during AR-RAPN for complex tumours can be useful for identifying the lesion and intraparenchymal structures that are difficult to visualize with US only. This translates to a potential improvement in the quality of the resection phase and a reduction in postoperative complications, with a better functional recovery.