Nikolai Begg – TRANSCRIPT
The first time I stood in the operating room and watched a real surgery I had no idea what to expect. I was a college student in engineering. I thought it was going to be like on TV. Ominous music playing in the background, beads of sweat pouring down the surgeon’s face But it wasn’t like that at all. There was music playing on this day, I think it was Madonna’s Greatest Hits. And there was plenty of conversation.
Not just about the patient’s heart rate, but about sports and weekend plans. And since then the more surgeries I watched, the more I realized this is how it is. In some weird way, it’s just another day at the office. But every so often the music gets turned down, everyone stops talking, and stares at exactly the same thing. And that’s when you know that something absolutely critical and dangerous is happening.
The first time I saw that I was watching a type of surgery called “laparoscopic surgery.” And for those of you who are unfamiliar laparoscopic surgery instead of the large open incision you might be used to with surgery, a laparoscopic surgery is where the surgeon creates these three or more small incisions in the patient. And then inserts these long, thin instruments and a camera, and actually does the procedure inside the patient. This is great because there’s much less risk of infection, much less pain, shorter recovery time. But there is a trade off.
Because these incisions are created with a long pointed device called a “trocar.” And the way the surgeon uses this device is that he takes it and he presses it into the abdomen until it punctures through. And now the reason why everyone in the operating room was staring at that device on that day was because he had to be absolutely careful not to plunge it through and puncture it into the organs and blood vessels below.
But this problem should seem pretty familiar to all of you, because I’m pretty sure you’ve seen it somewhere else. Remember this? You knew that at any second that straw was going to plunge through, and you didn’t know if it was going to go out the other side and straight into your hand, or if you were going to get juice everywhere, but you were terrified.
Right? Every single time you did this, you experienced the same fundamental physics that I was watching in the operating room that day. And it turns out it really is a problem. In 2003, the FDA actually came out and said that trocar incisions might be the most dangerous step in minimally invasive surgery. Again in 2009, we see a paper that says that trocars account for over half of all major complications in laparoscopic surgery. And, by the way, this hasn’t changed for 25 years.
So when I got to graduate school this is what I wanted to work on. I was trying to explain to a friend of mine what exactly I was spending my time doing and I said, “It’s like when you’re drilling through a wall to hang something in your apartment.” There’s that moment when the drill first punctures through the wall and there’s this plunge. Right? And he looked at me and he said, “You mean like when they drill into people’s brains?” And I said, “Excuse me?” And then I looked it up and they do drill into people’s brains. A lot of neurosurgical procedures actually start with a drill incision through the skull.
And if the surgeon isn’t careful, he can plunge directly into the brain. This is the moment when I started thinking, OK, cranial drilling, laparoscopic surgery, why not other areas of medicine? Because think about it, when was the last time you went to the doctor and you didn’t get stuck with something? So the truth is in medicine puncture is everywhere. And here are just a couple of the procedures that I’ve found that involve some tissue puncture step. And if we take just three of them Laparoscopic Surgery, Epidurals and Cranial Drilling, these procedures account for over 30,000 complications every year in this country alone. I call that a problem worth solving.
Let’s take a look at some of the devices that are used in these types of procedures. I mentioned Epidurals, this is an epidural needle. It’s used to puncture through the ligaments in the spine and deliver anesthesia during childbirth. Here’s a set of bone marrow biopsy tools. These are actually used to burrow into the bone, and collect bone marrow, or sample boney lesions.
And I already showed you a laparoscopic surgery trocar, but here it is again. Here’s a bayonette from the Civil War. If I had told you it was a medical puncture device you probably would have believed me. Because what’s the difference? So, the more I did this research the more I thought there has to be a better way to do this. And for me the key to this problem is that all these different puncture devices share a common set of fundamental physics.
So what are those physics? Let’s go back to drilling through a wall. So you’re applying a force on a drill towards the wall. Right? And Newton says, the wall is going to apply force back, equal and opposite. So, as you drill through the wall, those forces balance. But then there’s that moment when the drill first punctures through the other side of the wall, and right at that moment the wall can’t push back anymore.
But your brain hasn’t reacted to that change in force. So for that millisecond, or however long it takes you to react, you’re still pushing, and that unbalanced force causes an acceleration, and that is the plunge. But what if, what if right at the moment of puncture you could pull that tip back? Actually oppose the forward acceleration. That’s what I set out to do. So imagine you have a device and it’s got some kind of sharp tip to cut through tissue.
What’s the simplest way you could pull that tip back? I chose a spring. So when you extend that spring, you extend that tip out so it’s ready to puncture tissue, the spring wants to pull the tip back. How do you keep the tip in place until the moment of puncture? I use this mechanism. When the tip of the device is pressed against tissue, the mechanism expands outwards and wedges in place against the wall. And the friction that’s generated locks it in place and prevents the spring from retracting the tip.
But right at the moment of puncture, the tissue can’t push back on the tip anymore. So the mechanism unlocks and the spring retracts the tip. Let me show you that happening in slow motion. This is about 2,000 frames a second, and I’d like you to notice the tip right there on the bottom, about to puncture through tissue. And you’ll see that right at the moment of puncture, right there, the mechanism unlocks and retracts that tip back.
I want to show it to you again, a little closer up. You’re going to see the sharp bladed tip, and right when it punctures that rubber membrane it’s going to disappear into this white blunt sheath. Right there. That happens within 4 100s of a second after puncture. And because this device is designed to address the physics of puncture and not the specifics of cranial drilling, or laparoscopic surgery, or another procedure, it’s applicable across these different medical disciplines, and across different length scales.