WASHINGTON, May 20, 2025 (BSS/AFP) - Surgeons at a hospital in Los Angeles, California have successfully performed the world's first human bladder transplant, hospital officials said.

The surgery, performed May 4 at Ronald Reagan UCLA Medical Center, is a promising development for other patients suffering from serious bladder disorders.

The recipient of the innovative procedure was Oscar Larrainzar, 41, a father of four who had a large portion of his bladder removed due to cancer several years ago, the University of California, Los Angeles, said in a statement Sunday.

Larrainzar later had both of his kidneys removed due to cancer and end-stage kidney disease and was on dialysis for seven years.

He received both a bladder and a kidney from an organ donor and had them successfully transplanted in an eight-hour operation.

"The surgeons first transplanted the kidney, followed by the bladder; they then connected the kidney to the new bladder using the technique they had pioneered," the UCLA statement said.

Dr. Nima Nassiri, one of the surgeons involved in the historic transplant, said the procedure yielded positive results almost instantaneously.

"The kidney immediately made a large volume of urine, and the patient's kidney function improved immediately," Nassiri said.

"There was no need for any dialysis after surgery, and the urine drained properly into the new bladder."

Nassiri and fellow surgeon Inderbir Gill said full bladder transplants had not been performed previously due to the complex vascular structure of the pelvis, making it a technically difficult procedure.

"This first attempt at bladder transplantation has been over four years in the making," Nassiri said.

Previously, patients in need of bladder reconstruction could have one artificially created using a part of the intestines or have a stoma bag inserted to collect urine.

Those techniques had several short-term and long-term risks that doctors hope will be circumvented with the full bladder transplant, Nassiri said.