The purpose of this study is to explore whether robot-assisted surgery can reduce 30-day surgical complications compared to open surgery in kidney transplantation.

Participants are adult recipients of kidney transplantation. Upon entry into the trial participants will be randomly assigned eiher open kidney transplantation or robot-assisted kidney transplantation. The participants in both groups will be treated in accordance with up-to-date guidelines and care.

Our hypothesis is that robot-assisted surgery can reduce vascular complications by 15% and/or major surgical complicatons by 20% within 30 days of kidney transplantation compared to open surgery.

Kidney transplantation is the ultimate surgical treatment for end stage renal disease, and while medical transplantation therapy has developed tremendously and now allows for transplantation and long-term survival, even in seemingly incompatible donors and recipients, kidney graft survival still, to a large extent, depends on a smooth and complication-free surgical procedure. In the past decade surgical techniques have been expanded by the introduction of surgical robots to improve minimally invasive surgery and optimize post-surgical care. Previous studies suggest that robot-assisted surgery has the potential to reduce complications such as surgical site infection and blood-loss, facilitate fast-track or even ambulatory surgery for complicated procedures and recent studies suggest this may be the case for kidney transplantation too.

The aim of this trial is therefore to explore if robot-assisted surgery can reduce surgical complications following kidney transplantation compared to open surgery (standard of care) and investigate the patient trajectory following the two procedures in terms of late complications, graft function and mortality. The study design is a superiority, open-label randomized clinical trial to be conducted at Rigshospitalet, the largest transplantation centre in Denmark.

The primary outcomes consist of 1) reduction in vascular complications (graft arterial stenosis, bleeding requiring reoperation, symptomatic haematomas, renal vascular thrombosis). The rate of vascular complications is currently 17.3%. With a power set at 80% and a significance level set at 5% we hypothesize that Robot-Assisted Kidney Transplantation (RAKT) can reduce vascular complications by 15% within 30 days after transplantation compared to Open Kidney Transplantation (OKT). 2) Reduction in surgical complications Clavien-Dindo > grade 2. The rate of Clavien-Dindo >2 is currently 22.8%.

With a power set at 80% and a significance level set at 5%, we hypothesize that RAKT can reduce Clavien-Dindo >2 by 20% within 30 days after transplantation compared to OKT.

The study will randomize 106 participants with an anticipated drop-out of 10% (n=96). Immediate follow-up will be 30-days after kidney transplantation to observe occurrence of primary endpoints assessed by chart review including both in- and out-patient information. Follow-up through chart review will persist for 2 years in order to monitor long-term complications and assess secondary outcomes. Participants will be randomized with a 1:1 allocation ratio using the randomization module in REDCap with differing block sizes. Dropouts will be replaced by the same randomization number to ensure equal distribution.

The study is analysed as intention-to-treat. The primary endpoints are expected to be evaluated as percent of patients with complications compared between the two groups. Secondary outcomes will be represented descriptively and analysed according to the datatype. An interim analysis will be performed when 50% of the patients are enrolled in the study. Statistical analysis will be undertaken using R version 3.2 or later if available.

While robot-assisted kidney transplantation is still in its experimental phase, robot-assisted surgery is not and many urological procedures use robotic assistance with excellent results. With no randomized clinical trials to date comparing RAKT to OKT, this study aims to contribute with valuable evidence on the possible benefits of RAKT for both surgical outcomes and the post-operative and long-term patient trajectory.

Inclusion Criteria:

• Adult recipients for renal transplantation
• Both patients in dialysis as well as pre-emptive
• For recipients of kidney grafts from deceased donors, inclusion depends on the availabilty of the robotic platform and dedicated surgical team

Exclusion Criteria:

• High degree of calcification of the iliac vessels on the level of external iliac artery defined as occurrence of longitudinal plaques on non-contrast CT-scan or other relevant radiological imaging in recipient prior to transplantation
• Highly complex vascular anatomy in the donor kidney requiring multiple anastomoses as evaluated by surgeon
• Previous kidney transplantation with later allograft nephrectomy as evaluated by the surgeon preoperatively
• Patients whose abdominal anatomy may prohibit access to and placement of graft in the iliac fossa as evaluated by the surgeon preoperatively (i.e. previous laparotomy, rectal surgery, herniotomy, current multiple kidney cysts)
• Simultaneous multiple organ transplant
• Severe comorbidities contraindicating robot-assisted surgery
• Patients who are unable to understand relevant medical information and the implications of treatment alternatives and to make an independent, voluntary decision

All study data including study protocol, statistical analysis plan, informed consent form, and clinical study report can be shared when a proper agreement is formed according to the European Union (EU) General Data Protection Regulation (GDPR) protection statement.