Earlier this year, doctors  in California successfully transplanted a bladder into a  living patient for the first time.

Thanks to this surgery, the patient –  who’d lost his bladder due to cancer – was able to pee on his own for  the first time in seven years! This moment is a major advance  in organ transplant history.

But it kinda seems like it shouldn’t  have taken us this long to get here. I mean, the first successful human  organ transplant dates back to 1954. That was a kidney.

And we’ve been doing heart transplants since the 1960s and lungs since the 1980s. But the bladder has enough hidden complexity– and medical tradeoffs– that we couldn’t transplant one until 2025. So here’s why it took  humanity so long to transplant bladders and how we overcame those obstacles. [♪INTRO] We all pee.

But some of us take it for granted. You could have been born with  a neurological condition that makes it hard or even impossible  to control your bladder. These conditions are more  common than you might think.

For instance, one of the most  common birth defects out there is spina bifida, occurring in  around 1 in every 2,900 births. This happens when your spine does  not fuse properly during development. Then, in some cases, spinal  cord nerves don’t form properly.

And those nerves are supposed  to direct your bladder’s filling and emptying. So all of this  can lead to problems peeing. Fundamentally, bladders are just bags that hold urine until we’re ready to pee.

So they don’t sound complex …at all. Until you learn about all the stuff around them. At some point, you need to empty the bag.

And that happens thanks to  electrical signals from your brain that tells muscles in and around  your bladder to push the pee out. Without those signals and muscles, you would have no control  over when and where you pee. So bladders are entirely dependent on  the nervous system for instruction.

Your brain tells your bladder muscles to stay relaxed while you're filling your bladder. Then, when it’s time to go, your  central nervous system signals to clench bladder muscles and relax sphincter  muscles to let out your pee. So if you need a bladder  transplant, it’s not enough to just stick a new bladder in your body.

You need to hope that your nerves send the right information to that bladder. Because that’s not always a given. In contrast, your heart has its own electrical system separate from the central nervous system.

So it’s shockingly simpler to  transplant a heart in some ways. But neurological conditions that  mess with your central nervous system aren’t the biggest reason  people need bladder transplants. That title goes to cancer.

In one year, more than half a million people get diagnosed with bladder cancer. And worldwide, it’s a major  cause of cancer-related death, especially in lower income countries. So to keep you from dying of bladder cancer, doctors sometimes remove your bladder  in a surgery called a cystectomy.

But without a bladder, you  definitely can’t control your pee. So you can imagine that someone living without a bladder might like a new one. The thing is, there are more  complications to bladder transplants than connecting to nearby nerves.

Your pelvis has a lot of  complicated blood vessels in it. So doctors have struggled to  successfully hook bladders up to the circulatory system because there’s  just so much going on down there. Not to mention, your body  might reject the new organ.

So people who receive organ  transplants usually need to be on immunosuppressant drugs  for the rest of their lives. And since over 90% of cystectomies  are due to bladder cancer, it’s kind of a tough sell to  compromise your immune system and risk more cancer for your new bladder. Especially because you can  live without your bladder.

It’s cumbersome. But you can do it. There’s two main ways doctors currently get around the whole no-bladder thing.

One is through an ileal conduit and stoma. Basically, your pee doesn’t  come from your bladder. It gets stored there.

It’s made in your kidneys. If you take the end of your kidneys  that usually funnels into your bladder and attach a piece of  your small intestine to them, you end up with enough slack to  redirect that flow somewhere else. Generally through a hole that your doctor makes in your abdomen, near your belly button.

Then you can attach a bag, called  the ostomy bag, to that opening, called the ileal conduit, to catch your pee. And you’d empty that bag at your convenience …kind of like you’d empty  your bladder if you had one… but it’s a lot harder to  scroll on your phone while you empty an ostomy bag  because your hands are busy. There’s some pretty big downsides to this.

One is that you’re peeing into  a bag strapped to your body, and you have no control over how  much comes out of you and when. You also have to keep the hole and the piece of intestine sticking out  of your body really clean. So, there is a lot of maintenance.

Which is enough for some people  to opt for a neobladder instead. This is also a repurposed  piece of your small intestine. But instead of acting as a conduit,  it’s more of a bladder replacement.

People who have neobladders tend to have better control over when they pee. But they still come with some issues. One of those issues is because your pee is acidic.

Doctors recommend that your  pee averages a daily pH of 6, which isn’t quite lime juice, but there’s more going on than in a glass of water. And having acid swirling  around your bladder is fine. But just like stomach acid, it’s best  if it stays where it’s meant to be.

Unfortunately, neobladders don’t keep urine contained the same way a bladder would. Remember, neobladders are made of small intestine, which literally exists to absorb things. So sometimes neobladders  soak up pee and you end up upsetting the whole chemical balance of your body.

One common outcome of neobladder  surgery is a condition called metabolic acidosis, where your  blood acid level is way too high. And since your kidneys are supposed  to regulate your blood-acid levels, metabolic acidosis can lead to kidney failure. That would make neobladders  a less than ideal solution.

But don’t worry. Researchers have been batting around other bladder remedies for decades. But first all science needs  funding, so here’s an ad: Thank you for watching SciShow!

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One of the first experiments dates  back to 1917, when a scientist used connective tissue to make  a bladder replacement in dogs. It wasn’t a huge success, resulting  in hemorrhage from the operation. But technically it wasn’t a failure  of the bladder to do bladder stuff.

And the later human attempts weren’t much better. In the 1950s, doctors created  fake bladders out of silicone and inserted them into 34  patients who’d had cystectomies. Unfortunately, a lot of the  patients died, which stopped experts from doing that again, and  meant that the survivors had their silicone bladders removed  to prevent even more death.

Not really the outcome we’re looking for. Things weren’t going so well  in the transplant world either. By 1987, doctors tried to do a partial transplant into a 32-year-old using the bladder of an infant.

This worked …until it didn’t. The patient’s immune system rejected the transplant about five months later. It really wasn’t until the 21st  century that doctors started seeing some success beyond  the small intestine method.

A big breakthrough moment  came in the early aughts, when they created neobladders for seven kids with a severe form of spina bifida. This time, the neobladders were created from the patients’ own bladder cells. This seemed to be an effective way to prevent the kids’ immune systems from  rejecting their new bladders, because four years down the  road there were no hiccups.

Before these neobladders were implanted, the children leaked pee as  often as every 30 minutes. The cell-grown bladders weren’t  perfect, but they helped the kids hold more pee and control when  they peed more effectively. But there’s a reason we’re still  talking about transplants in 2025.

Another attempt a few years later failed when similar cell-grown bladders ruptured. They’re pretty tough to get right. Not only is pee acidic, but  it can also contain toxins.

So having all of that pee around  discourages stem cells from growing. Meaning that a lot of these cell-grown bladders just scar up and stop working. Despite setbacks, the last few years have been full of excitement around cell-grown bladders.

The success of that trial with  seven kids means that people have poured a lot of time and  money into this line of research. But we are still a long way  from using home-brewed bladders. So, like it or not, transplants are kind of the alternative to the bladder-less lifestyle today.

And transplants haven’t been  all smooth sailing either. The first partial transplant  happened back in 2008, when doctors successfully patched a bladder from a two year-old into a  one-year-old kid. Progress!

But before we got to a full bladder transplant, we needed to solve the vasculature issue. Through practice on corpses and brain-dead donors, doctors eventually figured  out that they could simplify the surgery by connecting some blood vessels to each other while the bladder was still on ice. Finally, it was time to test it  out on a real living patient.

But they needed someone for  whom the tradeoffs made sense. That person ended up being Oscar Larrainzar, a 41-year-old cancer survivor. Larrainzar was on dialysis, and this  had damaged his small intestine to the point that it couldn’t really be used  for a neobladder or in an ileal conduit.

He was also in need of a kidney transplant, so even though he was a cancer survivor, he was going to be on immunosuppressants anyway. The tradeoffs were trade-offing. Larrainzar was an excellent  candidate for the bladder transplant.

On May 4 2025, Larrainzar went into surgery. He came out with the two  for one deal of the century: a new kidney and a new bladder. A few days later, he was able to  pee for the first time in years.

This news is still too new to know how this full bladder transplant will work out in the long run. But the immediate results are pretty awesome. It’s not clear yet if bladder  transplants will stick around.

Larrainzar’s body could  still reject the new bladder. And we don’t know what the long  term side effects might be. But hopefully they’ll be sorted  out through future clinical trials.

Larrainzar’s transplant is  part of a larger experiment to test out the viability of bladder transplants. So more should be coming soon! Okay, the video is over now.

I know you’ve been thinking  about it since you saw the title. You can finally go to the bathroom. Me too. [♪OUTRO]