Continuous renal Surface Cooling Technique (CSCT) in robotic assisted kidney transplantation: technique and outcomes from a high-volume center, a prospective cohort study

Abstract

Background: Robot-assisted kidney transplantation (RAKT) surgery is an advanced minimally invasive technique, albeit with extended surgical and kidney ischemia time. To safeguard kidney function, we have devised a continuous surface cooling method (CSCT) for intraoperative kidney cooling. Materials and Methods: Patients receiving RAKT were divided into CSCT group and conventional group. The CSCT is a custom-designed apparatus composed of a single-layer plastic bag, featuring an inflow and an outflow that create a closed circuit for the continuous flow of cooling saline. The conventional group utilized ice slush for kidney graft cooling (Vattikuti Urology Institute-Medanta Technique, VUIMT). Patients who underwent open renal transplantation during the same period were also included in the study. All patients were subject to a minimum 2-month follow-up. And 1:3 propensity score matching was used to minimize selection bias. Results: A total of 144 patients underwent CSCT, 47 underwent VUIMT, and 196 underwent open surgery were included in the study, while after matching, 129, 43, 129 patients were included in the three groups, respectively. The median follow-up time was 19 months. None of the patients experienced delayed graft function, patient mortality, or graft loss. After introducing the kidney into the abdominal cavity for 20 minutes, the surface temperature of the kidney in the CSCT group was notably lower compared to the VUIMT group (15.42±0.88 vs. 21.74±2.53°C, P=0.001). This temperature disparity became more pronounced at 65 minutes (19.74±1.61 vs. 29.82±1.63°C, P<0.001). At both 3 and 7 days post-transplantation, creatinine levels in the VUIMT group were significantly higher than those in the CSCT and open surgery groups (at 3 d, 244.13±45.61 vs. 182.51±55.47 in CSCT group, P<0.001, or vs. 182.77±61.32 in the open surgery group, P<0.001; at 7 d, 162.42±54.86 vs. 143.11±44.32 in the CSCT group, P<0.001, or vs. 135.23±45.27 in the open surgery group, P<0.001). No differences were observed in blood creatinine, estimated glomerular filtration rate, and perioperative complications between the CSCT and open surgery groups. Conclusion: The CSCT presents a significant advantage over the traditional VUIMT method in terms of kidney cooling and early postoperative kidney function preservation. Additional research is required to ascertain whether the CSCT can enhance the long-term prognosis of kidney transplant recipients.