Robot-assisted kidney transplantation (RAKT) has been proven feasible and effective. The European Association of Urology–Robotic Urology Session working group has shown solid results in the living donor setting in terms of surgical success and graft function.^1–4 Moreover, the feasibility of this technique for deceased donor graft recipients has been already been proven.⁵ However, despite its success, there are still limitations to RAKT including the maintenance of the graft temperature during rewarming time and, secondly, the presence of atheromatic plaques in the recipients’ iliac vessels.

Graft hypothermia during vascular anastomosis is crucial to preserve postoperative graft function, and up to now it is typically maintained by placing ice slush on a gauze jacket that surrounds the kidney before its positioning in the operative field and additional intermittent insertion of ice slush in the abdominal cavity. This technique may be suboptimal because of the nonconstant graft temperature and the risk of ileus due to the continuous intra-abdominal ice melt flowing.

To overcome this first limitation, we developed a Cold Ischemia Device (CID) according to the Idea, Development, Exploration, Assessment, Long-term Study (IDEAL) model for surgical innovation, with the aim to maintain a low (<20°C) and constant graft temperature during the whole rewarming time.⁶ In collaboration with Grena Ltd, in the IDEAL phase 0, we developed a jacket composed of 2 plastic layers connected to an inflow and outflow tube, where the saline solution flows in a circuit fashion thanks to a peristaltic pump (fig. 1). A window through which the graft vessels can be exposed allows performance of the anastomosis. The device was tested in an ex vivo setting to assess its cooling performance and to be compared to the standard gauze jacket technique using animal kidneys. Then, in collaboration with Orsi Academy (Belgium), CID was effectively employed in an in vivo animal model to simulate the real-life setting maintaining a constant low temperature of the graft. Finally, in the IDEAL phase 1, the device was employed in human open and RAKT demonstrating the effectiveness in keeping the graft at a low and constant temperature throughout the rewarming time without any modification in the standard surgical technique (fig. 2). This device will allow the surgeon to include cases that may need a longer rewarming time (>50 minutes), such as more complex cases,^7,8 and extend the teaching programs in both kidney transplantation and RAKT maintaining the safety of the procedures.⁹

Figure 1. A, absolute values in temperature at each timepoint (IDEAL phase 2a). B, absolute values in temperature at each timepoint (IDEAL phase 2b). C, graphic representation of refrigerating circuit through which saline flows in a closed system thanks to silicone tubes connected to a peristaltic pump and saline reservoir filling space between 2 thin films refrigerating graft.

Figure 2. A, Final version of cooling system, consisting of 2 layers of a thin film sealed in such a way that channels are created and fluid can pass from one end of the jack to other. B, after filling, wall thickness increases to about 1 cm. CID used in open kidney transplantation before carrying out vascular anastomosis. C, once kidney is perfused (at end of vascular anastomosis), device is removed. RAKT with CID showing thermal probe used for temperature measurement (D) and kidney reperfusion and device removal (E).

Figure 3. 3D model superimposition using augmented reality in patients without plaques.

Figure 4. 3D model superimposition using augmented reality in a patient with plaques.

The second limitation regards the feasibility of the robotic approach in recipients who present with atherosclerotic plaques due to a chronic vascular disease caused by chronic renal dysfunction and long-term dialysis. Unlike the open approach, where the arterial plaques can be felt by the surgeon, in minimally invasive surgery the lack of the haptic feedback limits its application due to an unsafe vascular clamping and arteriotomy. The transplant unit of Fundació Puigvert, in collaboration with the University of Turin and Medics3D (Turin, Italy), employed the 3-dimensional (3D) imaging virtual reconstruction of conventional computerized tomography scan images with the aim to guide the surgeon during vascular clamping and arteriotomy using augmented reality (AR). This technology allows the surgeon to locate the arterial plaques and avoid them during the procedure. In the IDEAL phase 0, the 3D virtual models of the iliac vessels, together with their plaques, were obtained from computerized tomography. These models were printed and compared to the real anatomy of patients during open transplantation by real-time haptic feedback to verify the correspondence. Then the 3D models obtained from patients without plaques were superimposed using AR on the surgical field thanks to the augmented reality system for Super Imposed Image Guided Surgery (SIIGS™), integrated on the robotic console software, to check the anatomical correspondence during the arterial clamping and arteriotomy (fig. 3). Finally, in IDEAL phase 1, we tested the AR on a patient with iliac artery plaques (fig. 4). The 3D-AR enabled us to safely clamp the artery in the correct position and to find the portion to correctly and safely perform the arteriotomy. This technology aims to expand the indication for RAKT to patients with atheromatic vascular disease improving the surgical safety of the robotic approach in this setting.

Despite the success of RAKT, the robotic approach is still far from being considered the standard technique, due to its limited use in deceased donors and the need for a good experience in robotic surgery. The recent technological advancements can expand the indication for RAKT to a larger number of patients including the recipients of graft coming from deceased donors. Thus, the robotic approach is rapidly passing from an experimental technique to the new horizon in kidney transplantation.