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Microtrabecular Fracture of the Scaphoid

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So I'm here with Dr. Stern.

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3 00:00:01,670 --> 00:00:03,650 We're looking at a 14-year-old man who fell

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and now has snuffbox radial tenderness.

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And we've got a coronal T1.

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It looks like we're not in the plane

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of the scaphoid, but we actually are.

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It's just the scaphoid is edematous.

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We've got a coronal water-sensitive PD spur.

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The detection sequence on the left

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is the characterization sequence.

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And then we have on the right a 3D

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GRE, which is not so good in the bone.

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You can see how difficult it is to spot the edema.

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Or this little fracture line right here,

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or a slightly bigger fracture line.

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And, um, that's one reason why we don't

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use gradient echo for medullary bone.

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Um, one quick comment before we talk

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about the management of this case.

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The way this case was done.

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Probably a good teaching point in the

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improper way to evaluate the scaphoid.

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You know, they did a coronal, and

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then they went ahead and did a straight axial.

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And then off that straight axial,

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they did a straight sagittal.

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And a lot of my hand surgery friends

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frown on that technique, and the more sophisticated

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the surgeon, the more they want a parallel

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view, a perfectly tangent view to the scaphoid.

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So the way to get that is to do what I

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call a para-axial or a para-sagittal

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down the long axis of the scaphoid.

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Then you'll have something that looks like this.

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You'll see the scaphoid in that orientation.

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Then you hit it again with another oblique, and

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now you'll have the scaphoid in absolute profile.

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And this is a good way to do it, both on

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CT and MRI, and you will, you will have

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a happy clinician and happy surgeon.

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Wasn't done here.

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We still have the information we need, which is

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a microtrabecular injury of the scaphoid bone.

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So, the scaphoid, Let's scroll it, and

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I'm gonna blow this up a little more so

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you can see the scaphoid really well.

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And now you can kinda see these little micro

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trabecular lines creeping around the scaphoid.

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Alright.

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Surrounded by ill-defined edema.

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And then, on the next cut, you can actually see

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a linear fracture line that's intramedullary.

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There's no cortical step off.

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And there's plenty of edema to go around,

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but it doesn't go all the way through.

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So, we want to define what kind of fracture we have.

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Is it an enchondral bone, medullary

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bone, spongy bone fracture?

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Is it transcortical?

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Is there a step off?

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Does it go part of the way across?

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Does it go all the way across?

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Is it waist?

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Is it proximal?

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All the, all these things matter, uh, in terms of

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the management of the patient and the potential, uh,

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future complication risks such as avascular necrosis.

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And then one other comment before I turn it over to Dr.

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Stern.

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I like to, to grade my bone injuries.

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And this is just how I do it.

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So the earliest grade of bone

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injury is simply a contusion.

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I'm just gonna number them.

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Uh, just to give you some orientation.

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So a low-grade contusion, LGC, that would

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just be on the most sensitive sequence.

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You just see a little bit of edema, or you

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see some edema, but the T1 looks normal.

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Now that's not the case here.

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The T1 isn't normal in a, in a, what

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I call a stage two or the next level up.

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We have a high-grade contusion.

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So we have the same exact thing, except

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this time, edema here, and edema here.

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But you don't see any lines.

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Then in the next step, you have what I call a

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type of microtrabecular injury, of which all of

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these are, that I would call a microtrabecular

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fracture, or a so-called hairline fracture,

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which we've used culturally over the years.

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And that's when you have, we'll call

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this a microtrabecular fracture.

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And that's when you have these little lines,

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but no step off and no transcortical violation.

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Then you start to get into higher grades of injury,

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macro fractures, displacement, angulation, and all

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the stuff we know from conventional radiographs.

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And that's usually the progression.

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Now we're talking about acute injuries,

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we're not talking about repetitive trauma,

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like stress or insufficiency-type fractures.

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So now, what do you do with a youngster like

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this, where you have what I would consider a

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lower grade injury? I think the plain film,

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even though we don't have it, it

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would be normal in a case like this.

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You've been very articulate in describing this,

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and I think, uh, in my management of patients

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with snuffbox tenderness, the MR has made a quantum

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difference in my therapeutic recommendations.

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Uh, specifically, uh, in this case, uh, I think the,

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uh, integrity of the scaphoid is perfectly intact.

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And, uh, I do not think that, uh, operative

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fixation, uh, of any type, uh, would be indicated.

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I would treat this in a cast, uh, and

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anticipate over time, uh, six weeks to,

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six to ten weeks, uh, particularly being,

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uh, an adolescent, that this would heal.

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The, the really difficult decisions for hand

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surgeons, who are, of course, Orthopedic

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surgeons, of course, are biased, is if there's a

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complete fracture line, even if it's non-displaced.

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So the big issue in my field is, how do you

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manage a non-displaced fracture of the scaphoid?

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We know that if a non-displaced

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fracture is treated non-operatively in

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a thumb spica cast, it is going to heal,

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uh, probably 90% to 95% of the time.

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We also know that if you do surgery, there's

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always risks of, uh, complications from infection

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to hardware issues, et cetera, et cetera.

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I think the tendency today for non-displaced complete

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fractures, the high grade, almost macro injury,

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as you described it, would be to internally fix

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it because it heals

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more quickly and there's a more rapid

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return to play, so, uh, but certainly it's

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acceptable, for example, in Great Britain, the

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Brits are a little more conservative with that

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type of injury, again, non-displaced, completely

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non-displaced fracture, but they may

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very well treat it in a cast, thumb spica cast.

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Whereas I think in the States, there would

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be more of a tendency to do some type of, uh,

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headless compression screw internal fixation.

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Now, I've heard the term Herbert

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screw, a modified Herbert screw.

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Are there different types of

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screws that you put in there?

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What's the You know, too many to choose from.

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Yeah, lots

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and lots of choices.

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I think they all basically do the same thing.

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They're internally stabilizing the bone and

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providing some degree of compression to the bone.

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I just want to make one other point.

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And this is really relevant

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for healing, especially on CT.

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But you can see the technologist

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did a straight orthogonal.

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And now that I've lived in the hand surgery world

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for a quarter of a century, I've learned from them.

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What they need and why they need it.

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And for instance, if you look at even, even the

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orthogonal sagittal, the fracture line looks

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a little deeper than it does in the coronal.

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Here on the coronal projection, it looks

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like it's only about 50 percent depth.

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Now you go to the sagittal, it would have been nice

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to have a parasagittal right down the long axis.

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You can see that even though the line doesn't go

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transcortical, it does go more than 50 percent across.

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So, you know, you've really got to kind of

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weigh and look at every single projection.

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Now when we're talking healing,

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we actually have a fracture without

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displacement, but a cortical step-off.

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We use 50 percent bridging on CT to

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decide whether a person returns to play.

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Uh, have you ever used that number?

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Uh, because I know I've given it to you in the past.

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Well,

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it's, no, actually, uh, that's

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kind of been your number.

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And it's, uh, it's, uh, it's now in the literature, so.

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Again, there's some subjectivity to what 50

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percent is, but I think in general, uh, if the

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radiologist tells you that there's 50 percent

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healing, with a fair degree of certainty, you

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can let that individual return to play with or

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without some kind of, uh, protective splint.

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One

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other bit of clarity and then I'll log off.

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When we're talking 50%, we don't just look at

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one cut and say, okay, that's 50 percent across.

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We do it by volume.

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So we go all the way from front to back,

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we look in the sagittal, and we make sure

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that we're talking about a volumetric 50%,

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not a single area 50 percent on one slice.

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Let's move on, shall we?

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Yeah.

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Thank you.

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Sure.

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Dr. P and Dr. Stern out.

Report

Faculty

Stephen J Pomeranz, MD

Chief Medical Officer, ProScan Imaging. Founder, MRI Online

ProScan Imaging

Tags

Trauma

Musculoskeletal (MSK)

MRI

Idiopathic

Hand & Wrist

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