Historic milestone in surgery: First bladder transplant performed on a human

Surgeons at UCLA Health and Keck Medicine at the University of Southern California (USC) have performed the world's first bladder transplant on a human .

The patient, Oscar Larrainzar, had lost most of his bladder during the removal of a tumor . What remained of the organ was Too small and impaired for function. Later, both kidneys were removed due to renal cancer in the context of pre-existing end-stage kidney disease. As a result, he was on dialysis for seven years.

The procedure was successfully completed at Ronald Reagan UCLA Medical Center on May 4, 2025, UCLA Health reported in a statement. This is a historic milestone for medicine , and involved Dr. Nima Nassiri , a urologic transplant surgeon and director of the UCLA Vascularized Composite Bladder Allograft Transplant Program, and Dr. Inderbir Gill , founding executive director of the USC Urology Department.

"The kidney immediately produced a large volume of urine, and the patient's kidney function improved immediately . There was no need for dialysis after surgery, and urine drained properly into the new bladder," explains Dr. Nassiri.

"Despite the complexity of the case, everything went according to plan and the surgery was a success. The patient is doing well, and we are pleased with his clinical progress to date," adds Dr. Gill.

Inderbir Gill, who is also a professor and distinguished professor of urology and the Shirley and Donald Skinner Chair in urologic surgical oncology at the Keck School of Medicine of USC, said the surgery “marks a historic milestone in medicine and could influence how we treat carefully selected patients with highly symptomatic, terminal bladders who no longer function.” “Transplantation is a lifesaving and life-enhancing treatment option for many major organ conditions, and now the bladder is joining the list,” he added.

This first attempt at a bladder transplant has been in the making for more than four years, according to Dr. Nassiri. "For the appropriately selected patient, it's exciting to be able to offer a potential new option," he notes.

"Bladder transplantation has been Dr. Nassiri's primary academic focus since we joined the UCLA faculty several years ago. It is extremely gratifying to see him translate this work from the laboratory to human patients at UCLA, which operates the most active and successful solid organ transplant program in the western United States," said Mark Litwin, MD, chair of urology at UCLA.

The greatest risks of transplantation are possible organ rejection by the body and the side effects caused by the immunosuppressants required to prevent rejection. "Because of the need for long-term immunosuppression, the best candidates currently are those already receiving immunosuppression or who have an imminent need for it," says Nassiri.

Nassiri, a former urology resident at the Keck School and now an assistant professor of urology and kidney transplantation at UCLA, and Gill worked together for several years at the Keck School to develop the new surgical technique, design clinical trials, and obtain the necessary regulatory approvals.

The two physicians collaborated for several years to develop the surgical technique. Numerous preclinical procedures were performed at USC and OneLegacy, the Southern California organ procurement organization, in preparation for the first human bladder transplant .

During the complex procedure, surgeons transplanted the donated kidney, followed by the bladder. The two new organs were connected using Nassiri and Gill's pioneering technique. The entire procedure took approximately eight hours .

Current treatment for severe, terminal cases of bladder dysfunction or bladder removal due to various pathologies includes bladder replacement or enlargement. These surgeries use a portion of the patient's intestine to create a new bladder or pathway for urine to exit the body. While they can be effective, they carry many short- and long-term risks that compromise the patient's health, such as internal bleeding, bacterial infections, and digestive problems.

"A bladder transplant, on the other hand, results in a more normal urinary reservoir and can avoid some short- and long-term problems associated with bowel use," Nassiri says.

As this is a first in humans, there are naturally many unknowns associated with the procedure, such as the immediate and long-term function of the transplanted bladder, and how much immunosuppression it will require.

"Despite the unknowns, our goal is to understand whether bladder transplantation can help patients with severely compromised bladders lead healthier lives," Gill explains.

Bladder transplants have not been performed previously, in part due to the complex vascular structure of the pelvic area and the technical difficulty of the procedure. As part of their research and development efforts, Nassiri and Gill successfully performed numerous transplant surgeries at the Keck Medical Center of USC, including the first robotic bladder retrievals and successful robotic transplants in five recently deceased donors with cardiac function maintained on ventilator support.

The two surgeons also performed several non-robotic bladder retrieval trials at OneLegacy, allowing them to refine the technique while collaborating closely with multidisciplinary surgical teams.

The procedure was performed as part of a clinical trial at UCLA, but Nassiri and Gill hope to perform more bladder transplants in the near future.