02:02
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03:49
the area of interest on the screen so we can change our depth. Obviously this is too deep. Our area of interest is way at the top. If we come here, it's a little bit too narrow. We can't see the flexor tendons. So I had this at about 1.5cm. All right. So here's our nerve right at the top. And we are going to freeze the screen.
Now the nice thing is once you freeze the screen you actually can go back and forth a little bit. So don't feel like you have to get that perfect picture. You can always scan back and forth. And now we're going to measure the nerve. Carpal tunnel syndrome was diagnosed by the cross-sectional area of the median nerve.
And so we're going to use this function here and come over here to the trace function. We've done some work here at the University of Pittsburgh and elsewhere. That shows the trace function is the best way to measure. It's the most accurate. So we're going to tap the screen and then trace just inside the eponym.
So I'm tracing along the nerve right here. And then as I come closer if I tap the screen it'll give us our number. You can see the top here. Her median nerve cross-section area is 9.91mm squared. We typically use ten as the cutoff for carpal tunnel syndrome. So she would not have carpal tunnel syndrome based on this exam.
Some other cool features you can use. Let me unfreeze this. There is an AI function The Clarion has. I'm going to click the AI tool here, click on median nerve. And then the system actually recognizes the nerve right away. You see how quick it pick that up. It puts it in green and then we'll freeze it. And I think one of the neat things about this.
So that measured nerve at 10.67mm squared. And if I kind of go back and forth on the screen, that little recording you can see watch the number up here changing the upper part of the screen. It actually changes a little bit as we go. And what I often do is I'll kind of find the area and then I'll kind of scan back and forth and try to see which area.
I think that the green kind of stays mostly inside the up inner room. You can see maybe on this side right here, it's a little bit outside the room. So I'll come this way a little bit and kind of get a different number. See that one's a little bit better than that was 10.67. So that's how the AI works for um for carpal tunnel.
For a lot of people, it's not just the absolute value at the wrist. Let me turn that off.
03:57
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04:47
Uh, we're looking at ratios because our patient here is like five foot one, 120 pounds. You you want to say maybe you're going to have a different size nerve than an offensive lineman who's six, five, 350 pounds. And so you can scan approximately. So watch as I translate approximately. You can watch the median nerve as it goes up the forearm.
We're still following it right here, right here right here. And you get to about 12cm or right around five inches proximal forearm. We'll freeze the screen again. And we can get a measurement of this one as well. So I'll go to the trace function tap here trace around the nerve and bring it up. And so that measured 6.86 a woman from Duke named Lisa Hobson Webb popularized the wrist to forearm ratio.
And if your wrist to form ratio is more than 1.4, that's also diagnosed with the carpal tunnel. So we would take her 9.91mm squared divided by 6.86. And I can't do that math in my head, but that's probably less than 1.4 as well.
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05:55
So again, there's our nerve. Right at the top. We got 9.91mm squared. You know, how do we use this clinically. Well we talked about using ten millimeter square at the cutoff or a risk to form ratio of more than 1.4. The other thing we can look at is severity. So we know that based on the ultrasound it correlates fairly well with nerve studies.
Everyone loves nerve studies. So if you're nervous less than ten that correlates with negative nerve study. If it's between 10 and 12 that correlates with mild 12 to 14 moderate and more than 14 severe. So say she came in and heard was measuring 14mm squared and said, okay, probably a severe carpal tunnel and we should do surgery.
She comes in her nerves, you know, 10.01 just barely meeting the cutoff. All right. Let's talk about should we do splints, should we do injections and things like that. Um, so here's your carpal tunnel. There's your nerve at top. Here's your tendons. Here's your bone below. If you wiggle your fingers, you can see your tendons moving back and forth.
Your thumb is going to be over here. Wiggle your thumb. See that one moving. And that's your nerve right on top. As your nerve goes through, the carpal tunnel gets pinched and it tends to swell. And so we can scan back and forth and see up here in your forearm it gets a little smaller. And as we come out towards your wrist it gets a little bit bigger.
And as we go into your carpal tunnel, it really starts to shrink as it gets pinched. We know that as your nerve gets bigger, that becomes more significant for carpal tunnel syndrome.
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06:05
So that completes our assessment of the carpal tunnel using ultrasound and our demonstration of the Clarice AI function.