In Los Angeles, a man who had given up on a normal life walked into surgery expecting a kidney — and woke up with something far more radical.
For the first time, US surgeons have transplanted a donor bladder alongside a kidney, allowing a 41-year-old cancer survivor to urinate again after seven years on dialysis and without a functioning urinary system. The operation, carried out at UCLA’s Ronald Reagan Medical Center, is being watched closely by transplant teams worldwide.
A life put on pause by cancer and dialysis
The patient, identified as 41-year-old Oscar Larrainzar, had been living in a medical dead end. Years earlier, an aggressive cancer had forced surgeons to remove both of his kidneys and almost all of his bladder. He survived, but at a steep cost.
Without kidneys, he depended on dialysis several times a week to clean his blood. Without a bladder, his body had no natural reservoir for urine. Conventional options for people in his situation are limited and often harsh.
Many patients undergo urinary diversion surgery, where urine is routed through the intestine to a stoma in the abdomen and collected in an external bag. Others receive bladder “reconstructions” built from segments of bowel, which can help but often bring infections, metabolic problems and repeated hospital stays.
For patients like Oscar, medicine could keep them alive, but rarely gave them back a life that felt comfortable, dignified and independent.
By 2025, Larrainzar had spent seven years tied to dialysis machines and coping with the aftershocks of major cancer surgery. New treatments were not on offer. No one, anywhere, had successfully transplanted a human bladder.
Why bladder transplants were seen as impossible
While kidney, liver and heart transplants are now routine in many hospitals, the bladder has long been considered off-limits. Surgeons knew the hurdles well.
- The pelvis is packed with fragile blood vessels that are difficult to access safely.
- The bladder’s nerves are complex and not easily reconnected, threatening long-term continence.
- Any transplanted organ comes with a lifetime of immune-suppressing drugs and infection risk.
For decades, these obstacles led many teams to conclude that a donor bladder was simply too dangerous for the potential benefit. On top of that, research funding and training focused on more established transplant fields, leaving urologic reconstruction stuck with older, imperfect techniques.
At UCLA, though, an unusual organisational structure quietly set the stage for change. The kidney transplant programme sits within the urology department, rather than acting as a separate division. That meant kidney transplant surgeons, urologists and pelvic reconstruction experts worked side by side.
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This tight-knit setup allowed a single team to think about the urinary system as one unit, instead of separate organs handled by different specialties.
A double transplant that rewired the urinary system
On 4 May 2025, after four years of preparation and lab work, urologist and researcher Dr Nima Nassiri led an eight-hour marathon surgery on Larrainzar at the Ronald Reagan UCLA Medical Center.
Step one: restoring kidney function
The procedure began with a kidney transplant from a deceased donor. This step followed a familiar script: attaching the new kidney’s blood vessels to the patient’s pelvic vessels and connecting the ureter, the tube that carries urine, ready for drainage.
Once blood flow started, the kidney behaved as surgeons had hoped. It quickly began producing urine — a strong sign that the organ was healthy and well-perfused.
Step two: attaching a donor bladder
The real gamble came next. Surgeons implanted a donor bladder from the same individual, then used a specialized technique developed over years of experiments to link the new kidney to the new bladder.
They had to connect delicate arteries and veins, secure the ureter, and stitch the bladder to the pelvis in a way that would allow it to fill, store and release urine without leaking or blocking.
In the operating theatre, the new kidney began pumping out urine, and the transplanted bladder did something no human donor bladder had done before: it filled, then emptied without obstruction.
By the end of the operation, the team felt confident enough in the kidney’s performance to halt dialysis. For Larrainzar, that meant the end of a gruelling routine that had dominated his life for seven years.
A medical first with fragile promises
As striking as the early success appears, doctors are cautious. The transplanted bladder was not reconnected to its original nerves, which help control the urge to urinate and coordinate the pelvic muscles. That missing wiring raises questions about long-term continence and how naturally the bladder will behave.
For now, the focus is on making sure the organ continues to function, stays infection-free and maintains a healthy blood supply. Additional procedures or devices might be needed to help the patient empty the bladder safely if natural nerve control does not recover or adapt.
| Potential benefit | Associated risk or challenge |
|---|---|
| More natural urination without external bag | Uncertain long-term continence without nerve reconnection |
| Improved quality of life vs. bowel-based reconstructions | Technically complex pelvic surgery, risk of bleeding |
| Single donor providing both kidney and bladder | Limited donor availability and complex matching |
The heavy price of lifelong immunosuppression
Like all transplant recipients, Larrainzar must now take powerful immunosuppressant drugs for life so his body does not reject the kidney and bladder. These medications have transformed transplant medicine, but they come with a cost.
Patients face a higher risk of infections such as pneumonia and certain viral illnesses, because their immune systems are kept deliberately weaker. They can also develop metabolic complications, including diabetes, high blood pressure and bone thinning.
For cancer survivors, doctors watch especially closely. Some immune-suppressing drugs can encourage dormant cancer cells to grow again. Larrainzar’s team will monitor him for any sign that his previous disease is returning.
For people in a therapeutic dead end, accepting these risks may feel preferable to a lifetime on dialysis and invasive reconstruction options.
Researchers at UCLA plan to follow Larrainzar and future patients for years, tracking organ function, continence, quality of life and complication rates. Those data will guide who might benefit most from such a complex surgery and who should still be steered toward more conventional care.
Who could one day benefit from bladder transplants?
If the technique can be refined and proven safe in more patients, doctors see potential applications in several groups facing severe urinary system damage.
- People who have lost their bladder and kidneys after pelvic cancers or radiation.
- Patients born with major urinary tract malformations, for whom standard reconstruction has failed.
- Individuals with catastrophic pelvic trauma from accidents or war injuries.
That said, surgeons are unlikely to offer a bladder transplant to anyone who can be helped with simpler, lower-risk operations. The procedure is long, technically demanding and requires a rare donor situation: a healthy kidney and bladder suitable for transplant from the same person.
Key terms patients often ask about
Two medical concepts sit at the heart of this story and frequently confuse non-specialists.
Dialysis: A machine-based treatment that cleans the blood when kidneys no longer work. It usually requires three sessions per week, each lasting several hours, and can leave people exhausted. Ending dialysis often means a dramatic change in daily routine, travel freedom and diet.
Urinary diversion: A surgical rerouting of urine. In common forms, surgeons use a short piece of intestine to carry urine from the kidneys to an opening in the abdomen, where it drains into a collection bag. Some diversions are internal, but most still demand careful maintenance and can alter body image.
What this could mean for future care
Imagine a young patient whose bladder has been removed after a childhood cancer, now facing adult life with repeated infections, complex reconstructions and constant medical appointments. If long-term data from Larrainzar’s case and future trials show stable function, such a person might one day be offered a combined kidney–bladder transplant instead of a patchwork of surgeries.
Another scenario involves older patients already requiring a kidney transplant. In select cases where the bladder is severely damaged or removed, a double organ transplant could spare them from external bags and repeated pelvic operations, letting surgeons rebuild the urinary system in one coordinated step.
Each case would still require difficult trade-offs: higher surgical risk and lifelong immunosuppression versus the chance at a more natural way of living. For now, the operation remains experimental, but for one man in Los Angeles, the ability to pass urine on his own for the first time in seven years signals a quiet revolution in urologic surgery has begun.