Robotic Bladder Autotransplantation: Preclinical Studies in Preparation for First-in-human Bladder Transplant

Human urinary bladder transplantation has never been performed. From a technical standpoint, challenges include the complex deep pelvic vascular anatomy, limited intraoperative visualization, and high procedural complexity. In preparation for a first-in-human clinical trial, we report preclinical studies to develop the technique of robotic retrieval and autotransplantation of vascularized composite bladder allograft.

Institutional Animal Care and Use Committee, Institutional Review Board, and UNOS (United Network for Organ Sharing) approvals were obtained, and IDEAL (Idea, Development, Exploration, Assessment, Long-term Study) Reporting Guidelines were followed. Robotic vascularized composite bladder allograft recovery, back-table graft preparation, and robotic autotransplantation were performed in 3 vascularized model settings: living porcine (n=3), pulsatile human cadavers (n=2), and heart-beating brain-dead deceased research human donors (n=5). Our primary objective was to develop a reproducible technique for robotic vascularized composite bladder allograft transplantation. Technical success was defined by adequate, sustained vascularized composite bladder allograft reperfusion. Secondary objectives were intraoperative parameters, including operative time, graft ischemia time, and blood loss.

Successful robotic vascularized composite bladder allograft autotransplantation was achieved in 2 porcine, 1 cadaver, and 3 brain-dead research donors. In the heart-beating research donors, console time decreased with successive surgeries, and visual inspection revealed healthy revascularized autografts with prompt, global indocyanine green immunofluorescence uptake. In 1 heart-beating donor who was hemodynamically maintained for 12 hours postoperatively, reinspection confirmed excellent maintained global vascularized composite bladder allograft vascularity and bladder mucosal integrity.

To our knowledge, the first preclinical experience of bladder autotransplantation in vascularized models is reported, including robotic vascularized composite bladder allograft recovery, back-table reconstruction, and autotransplantation. This experience represents the essential preclinical work required to build toward the first-in-human trial of bladder transplantation, performed under a UNOS-approved genitourinary vascularized composite bladder allograft program (NCT No. 05462561).