**5. Conclusions**

Minimally-invasive surgical techniques have increased the acceptance of living kidney donation, but its high variability renders head-to-head comparisons of surgical approaches a complex task. In this bi-centric study, we compared more than 250 cases of 52 transperitoneal robotic DNs with 205 laparoscopic DNs. Operating time and length of stay were no di fferent between groups, but slightly longer than elsewhere, as DNs and transplantations were conducted simultaneously to reduce CIT, and most other national health systems do not allow longer inpatient stays. Other perioperative results (complication rates, WIT) and mid-term kidney function including DGF rates were comparable with published data, and did not di ffer between RDN and LDN. This was possible because both centers already had prior expertise in either LDN itself or robotic surgery in general. For this reason, patient-specific factors (preoperative kidney function, history of donor smoking) were the more relevant impacts upon donor and graft function.

**Author Contributions:** P.Z., F.F., and M.S. (Michael Stöckle) designed the study; P.Z. analyzed the data and wrote the manuscript; L.H., R.P., M.S. (Matthias Saar), J.L., S.S., A.M., J.K., L.L., K.B., T.S., F.F., and M.S. (Michael Stöckle) drafted and revised the paper. All authors approved the final version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** We would like to thank the working group for kidney transplantation ("Arbeitskreis Nierentransplantation", https://www.nieren-transplantation.com/) of the German Association of Urology for initiating this bi-centric work.

**Conflicts of Interest:** The authors declare no conflicts of interest.
