Dr. Daniel Neely presents 4 real patient cases in Pediatric Ophthalmology & Strabismus that have been submitted on Cybersight Consult. The examination, diagnosis and treatment of each case are also covered.
Lecturer: Dr. Daniel Neely, Indiana University
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DR NEELY: I’m Dr. Daniel Neely. I’m a professor of ophthalmology at Indiana University School of Medicine. Where I practice pediatric ophthalmology and strabismus. And today we’re going to try something new. Today we’re going to discuss approximately five strabismus cases that I have been involved with. And having been a consult advisor to people around the world for the last 10 or 15 years, I’ve answered approximately a thousand consults. And during that time, I can tell you that if you ever felt alone, you’re really not. We all face the same problems, and see the same kinds of difficult cases. And so what I’ve done is I’ve kind of picked five representative cases of what I see commonly. And these cases aren’t perfect, but I think they are reflective of what happens in the real world. And each case has been selected to highlight a specific teaching point that we’ll go through. As we do this, also, I’ll try to take any questions that come up in real time. And as time permits, we’ll have some other discussion at the end as well. And, Lawrence, you can see my screen now. Is that correct?>> Nope. You have to share your screen for us.
DR NEELY: My apologies. Let me get that going. Okay. So I assume you have it now. Okay. Before we start, one thing that I’d like to point out is that all of the Cybersight material is available at the Cybersight homepage. And you can see there’s a list of upcoming lectures. And I think there’s some very interesting material coming up with Dr. Raab continuing his strabismus lectures, and then Dr. Ciulla with the retinal OCT, and you can see that there’s just a — ptosis, thyroid eye disease — we have quite a diversity of really interesting subjects coming up. And down at the bottom, we see Dr. Donny Suh, a good friend of mine, doing a presentation on 3D printing, which I think is going to hold a lot of promise in our practices. Some very interesting tools. So keep in mind that all of these lectures are recorded, and that by going to the library section, you can see all of the recorded lectures that have been given. We have the surgical videos as well. On different topics. And then, of course, there are the textbooks and manuals from Orbis and other sources that are available free to everyone. So let me open up my PowerPoint. And what I’ll be doing, as we do this, is I’ll be toggling back and forth between the Orbis/Cybersight consult website, as well as this PowerPoint, where I’ve highlighted some of the teaching points from each case. The first case that I’ve chosen today is this one. This is from one of my new friends, Dr. Marlyanti, in Indonesia, where I was this past year. And to summarize this case, we have a 20-year-old male with a history of diplopia. This patient has an exodeviation, which has been gradual in onset, over the last year. And there’s no history of trauma or other systemic disease. I’ll show you a collage here. And then what we’ll do is I’ll open up the case, and we can look at these images one by one. After we’ve looked at these images, we’ll launch into a poll question. I’ll get your opinion as to what you think about this case. Then we’ll discuss the differential diagnosis, briefly, and then some of the treatment options. And again, to point out — these cases aren’t perfect, and we don’t always have follow-up on these cases, but what I’m mostly interested in is showing you how the deductive process goes on, as you evaluate complex strabismus cases. What should be going through your head, what information is important, and then what do you need to do to help that patient. And how do you choose which muscles to operate on. It’s not always so much about what you do. It’s about picking the correct muscles and doing the right thing. So let’s open up this case. Let me sign myself in here. And this first case is 25618. Which I’ll do here in a second. All right. So starting from the homepage here, there’s a search function up here, if you’re not aware of that. And you can search by a multitude of different keywords, dates, people’s names. But I’ll be putting in the case number here, which is 25618. And we’ll bring up our first case, as we do this. And… The reason I want to pull these up like this, rather than just show you PowerPoint slides, is I want to be able to scroll through and show you the photographs in real time. Another thing I’ll point out here is — you see that the current consult form takes up quite a bit of real estate. And I’m happy to announce that later this week, you’re going to see a new condensed form of this, a revised template, which I think will make life a lot easier. And the presentation of information a lot more concise for everybody. But here’s our first case. And again, center image is always the primary position. And here’s our preview. You can see that he does have an exodeviation of the right eye. And appears to have some ptosis. And it’s hard to tell if there’s any vertical deviation there. When we look at his motility, I like to go to side gazes first, and it looks like his motility in right gaze is pretty normal. Let’s go to left gaze. You can see in left gaze, his right eye is not coming in very well. He’s not even coming into the midline. And I would describe that as a -4 adduction deficit. And upgaze… Also, again, the left eye goes normally, but you see that right eye is not fully elevating, and here up and to the right, it’s definitely not elevating very well. On that right eye. And then let’s look at down and to the right. So the right eye is also not depressing. Left eye looks like it’s moving pretty normally in all directions. And again, up and to the left. The right eye is a little elevated, but not adducting very well. There’s almost, again, zero adduction. And then not much depression in the adducted position either. So left eye appears to be normal. And there are some significant motility restrictions on the right eye. So let’s go into our first poll question. Looking at these motility photos, what do you think is the most likely diagnosis? Number one, a third nerve palsy. Number two, a fourth nerve palsy. Number three, a sixth nerve palsy. Or number four, Duane syndrome. And as you’ve astutely determined, given this many extraocular muscles involved, third nerve palsy — 91% of you agree — is the most likely diagnosis. And I agree. This is a rather — mostly obvious diagnosis. But the reason I’ve chosen this case is because this is one of the most difficult problems that we face. These are really complex. Because you have such a limitation of motility and functioning muscles. Here we can see — we basically have only a lateral rectus, and maybe a superior oblique to work with. Now, one of the things that comes into — it’s important to know about third nerves in particular — is when you have an isolated third nerve palsy, whether or not the pupil is involved is very critical. And that is because the pupillary motor fibers tend to run on the outside of the nerve, and so when you have compressive lesions, the pupil is affected. If you have a dilated pupil, then that increases the probability that there might be an aneurysm or other compressive lesion involved. However, the microvascular third nerves tend to affect the deeper portions of the third nerve, and so a lot of times the pupil is spared. So if the pupil is spared, it tends to be a less dangerous situation. And again, we’re mostly thinking microvascular diabetes and hypertension. And I think this case is kind of concerning, in the fact that it was a gradual onset, and it’s a young person, who really probably doesn’t have much in the way of microvascular risk factors. All right. But this particular diagram — this is from Ed Buckley’s chapter in David Plager’s Strabismus book, which I think is very interesting. This is Strabismus Surgery, 2004. The thing I like about this book in particular is that it presents a patient, and then you get the opinion of three, four, maybe even five international experts. And you’ll see that they all have different opinions, as to what should be done, in many cases. I think that’s very helpful, to see that there’s more than one correct way to do things. And so this particular patient, because the pupil was involved, and we actually… It’s hard to see that in the photographs. Unfortunately, these in particular — the way the photographs are — we can’t enlarge them. But we do have them up here. We know that — here we have that the right pupil is abnormal in size. So because this patient had a history of a dilated pupil, and an isolated third nerve, then the multiple slice CT angiography was performed, and unfortunately no abnormality was found, and no aneurysm was found. But the cause of the third nerve remained elusive. So we don’t know why this patient had a third nerve palsy. And I think one still needs to be on guard, with regards to aneurysm in this case. All right. So how do you deal with these total third nerve palsies? Well, basically you have a couple options. You can weaken the two remaining active muscles, which are forcing the eye down and out. And predominantly, that’s the exotropia from the lateral rectus, and secondarily, you get the hypotropia, if the superior oblique is still functioning. You also can strengthen the paralytic medial rectus. However, it’s paralytic. You’re probably not going to get a great amount of effect from that. And if we have a partial nerve palsy, we also have transpositions. But if you think of what’s the biggest bang for the buck, that’s to do something to the lateral rectus. We’re talking a very large recession. A typical resection may be 8 millimeters or so, but we’re trying to get the lateral rectus behind the equator. So recessing that lateral rectus 14, 16 millimeters, pretty much as far back as you can, and doing that by suturing directly to the globe — if you do this on a hangback, that has the option of the lateral rectus kind of creeping forward. So the hangback is easier, but might not give you as much effect. Other people might recommend extirpating it, or removing as much of the lateral rectus as you can, even as far back as Tenon’s capsule. But when you do this, the lateral rectus is still pulling on the periorbital tissues. And so you’ll see there’s still abduction effort, even though they’ve had these really extreme surgeries. And so many people have now gone to fixating the lateral rectus to the original wall. And you can do this — you need a very curved needle to do this. And one example is written here. This C1 taper point, which is a cardiovascular needle. It’s a heavy needle, and it’s curved. And if you disinsert the lateral rectus from the globe, and then suture it to the periosteum, just posterior to the orbital rim, well, now, when that lateral rectus contracts, it doesn’t move anything. So it makes it very difficult to have an abduction effect on the globe. And so that’s another nice way to really isolate that lateral rectus. And a lot of times, combining these two, with a very large resection of the medial rectus. Now, the medial rectus is dead, so we’re not really expecting to get a lot of effect from that. But you’re resecting such a large amount as to create a restriction. Resections of 10, 14 millimeters. And we want to see that that eye is in an esotropic position at the end of the surgery, because it’s going to stretch out and move over time. And if there is a hypotropia, you can superplace that. Move the resected medial rectus upward, and that will bring the eye up, to correct the hypotropia. If you have a partial third, you can move it the other way. If you have a hyper, shift the medial down, and that will take the eye down. Now, the predominant reason, however — so you can shift the medial up or down. However, most of the time, the reason you have the hypotropia is because the superior oblique still works. 4th cranial nerve. Now, it doesn’t always. The third and fourth nerve are right adjacent to each other, so sometimes the same process affects them both. But if you can identify that the superior oblique is functioning, and you do this by having the patient look down, preferably in the slit lamp. If you see incyclotorsion as they look down, that tells you that the superior oblique is functioning. So doing a tenotomy to prevent that hypotropia can be quite helpful. And this is usually performed as a secondary procedure, after you might go ahead and do the medial rectus resection. And the reason is: If you do the medial rectus resection, and yet you’re still exotropic, rather than just tenotomizing the superior obliques, you might choose to transpose the superior oblique. It’s not something we do commonly, but you can shorten the superior oblique tendon and move it so it’s adjacent to the superior corner of the medial rectus, and by doing that, you create a bit of a tether, so you can help pull that eye in. I don’t think there’s a lot of active adduction from this, but it can certainly be one more way to tether that eye in, to help with these more difficult cases. So that’s our first case. And I’ll see if I can… All right. So taking the first question here, what’s the justification for fixating the lateral rectus 5 to 6 millimeters behind the orbital rim? It is technically very difficult. And I would agree with that. It is technically very difficult. And I think it’s more difficult if you have the wrong needle. If you have the right needle, which is something heavy and curved, then it’s not that difficult to do. But I think from what I’ve seen, in a lot of places, it’s very difficult to find useful needles for this. Using a regular strabismus needle doesn’t work very well. They’re too light and they just bend and break. Now, you don’t necessarily need to expose the periosteum of the lateral orbital wall. I do this with a rather blind pass, just by pressing the tissues flat against the orbital wall, with ribbon retractor, or Desmarres retractor, or Barbie retractor, and then just getting a bite through the tissue and into the periosteum with the large C1 needle. So yes, it can be difficult. But it can also be very effective. But you don’t have to do it. If you don’t have an appropriate needle to do this, just do the extirpation or large recession, and combine that with a very large medial rectus resection. It’s a good point. But anything can be done if you have the right tools. I don’t think the technique itself is the challenge. It’s having the right needle. All right. So let’s go back to our PowerPoint. And we’ll get into the next case here. So our next case comes to us… From another one of my friends in Cambodia. Dr. Phara Khauv. And Dr. Khauv and I have worked together for many years. He’s doing a great job. This first case from him is a nine-year-old male who has a history of head tilt to the left. So head tilt to the left. And the complaint is that the left eye goes up, when the head is tilted to the right. So what sounds like a positive Bielschowsky head tilt test. Immediately we think of things like superior oblique palsies and that kind of thing. So here are the photos from this case. You can see he does have a bit of a head tilt to the left there. Let’s open this case up so we can take a nice close look at it. Back up to our search. And again, this is 25777. And really, any time that you have head postures, I think these are always interesting questions that come up. And let’s just skip ahead to images. So again, here’s his primary position. And I like this preview function, where you can scroll through and look at the images. If you want to see something larger, then just open it up using that larger icon. And what do we see here? His head — his chin is — his head is kind of tilted to the left. Looks like his chin is down. And what do we start to think of? We start to think of things like null points. We start to think of vertical strabismus. We start to think of paralytic strabismus. Let’s look at his motility in different directions. So that was primary. Here he is in right gaze. Looks pretty good there in right gaze. And let’s look at him in left gaze. So here’s his left gaze. And you can tell already on the preview that he’s rather — a large discrepancy in his alignment. So he’s got a very large left hypertropia in left gaze. All right? And then upgaze… Looks relatively good. Up and to the left. Looks relatively good. Up and to the right looks relatively good. So I’m really kind of opening up the ones that seem to be abnormal. Down and to the right seems pretty good. Straight down — I don’t think that’s quite perfect. You can see the left eye is not depressing very well. And so then let’s also look down and to the left. Down and to the left. Really not depressing very well. All right? So we have someone with a vertical strabismus. Abnormal head posture. And he’s got this incomitant vertical strabismus. And so this brings us to our next poll question. And when you have these incomitant vertical strabismus cases, which test do we find to be particularly helpful? And really want to be comfortable with? Is it the Worth 4 light test? Is it the 3-step test? Is it the ice bucket challenge? Or is it the mannequin challenge? This is a bit of… Being a bit facetious here. But it’s only because this test is very critical to evaluating complex strabismus cases. And 100% of you appropriately identified the 3-step test as the correct test. And I want to talk about that. Because I see that a lot of people aren’t comfortable with that. In this particular case… I want to show you his head tilt test. I think it’s rather interesting here. I’ve got it open already. You can see we’ve been able to attach some videos as well. So here’s video of this patient. And… Tilting to the left, he looks pretty good. Tilting to the right gets a large left hyperdeviation. So right… Or rather left… Right head tilt… He gets a large right deviation. Left hyper. All right. Now, the three-step test. Here you can see in this case I was discussing this with Dr. Khauv, and showing my technique for how to interpret this testing. And basically the three-step test has exactly that. You can see one, two, three. Three steps. And so let’s go through the three-step test with this particular patient. So to do that, I’m gonna go back up to his collage. Here. And then come back to my PowerPoint. So we can see this. All right. So the very first thing we do is I’ll — let me bring up the whiteboard. The very first thing I’ll do when I see these patients is I’ll plot out the muscles. So we’re gonna have right eye over here. We’re gonna have left eye over here. And we’re going to plot out the cyclo-verticals muscles. So the superior rectus takes the eye up and out. The inferior rectus takes the eye down and out. And the inferior oblique takes the eye up and in. And the superior oblique takes the eye down and in. Okay? And then do the same thing over here. IO. The SO. And the SR. And the IR. So why these? These are all the cyclo-vertical muscles that will produce positive head tilt test. All right. So in this particular patient, he had — it looked like he has a left hyper. So a left hyper… A left hyper is possibly a weakness of his depressors. So we circle the two depressors on the left eye. Now, a left hyper is the exact same thing as a right hypo. Correct? So if it’s a right hypo, rather than a left hyper, that could be a weakness of the elevators on the right eye. So we circle those two. So identify which eye is hyper, and then circle the depressors on that side. Now, our patient — what we now want to know is the hypertropia worse in left or right gaze? We saw in right gaze, it looked pretty good. In left gaze, he was really out of alignment. So we know we have to be dealing with the weakness of a muscle that works in left gaze. So back to our whiteboard. We circle those that are working in left gaze. Left gaze. Left gaze. All right? And then the final step is… Is his hypertropia worse with the right head tilt or left head tilt? And we had a video that showed us that he was worse with right head tilt. So we’re simply going to then duplicate — circle the muscles that are working in that right head tilt position. All right? So you’re kind of just mimicking where his head posture is. Close that video out. So now… Now what we see is that the intersection of those is on the left eye, and it’s around the left inferior rectus. Normally we do the three-step test, expecting to find that it’s a superior oblique palsy. And that’s the most common outcome. But the three-step test works for all the cyclo-vertical muscles. So in this case, we have something that looks like an inferior rectus weakness on the left side, according to our three-step test. What else do we have that would indicate that? Let’s go back to his primary position. So his chin is down and to the left. People, if they have a paretic muscle, they usually will put their head posture in the position of the paretic muscle. So if he’s got a weak left inferior rectus, his face should be down and to the left. And that’s exactly where it is. So his head posture is consistent with inferior rectus weakness.
>> You want to just share your screen?
DR NEELY: Yes, sorry, Lawrence. Thank you. All right. I’m assuming I have it back now? Almost? Okay. So let’s look at his… Since I may not have had this on, let’s look at his head posture now. So his chin is down and so the left. So if he has a paretic left inferior rectus, this should be the position. He’s putting his face down where the eye won’t go. So this is consistent with what the test just showed us. So what did we find at surgery? So we’ve done the three-step test. And we feel like it isolates the left inferior rectus. Now, why is that? I’ll kind of skip talking about Hering’s law and the yoke muscles. We do cover this in the advanced strabismus webinar, which is recorded and available. But I want to get to as many of our five cases as we can, so let’s move through this. And his operative findings… We did do traction testing of the left superior rectus, to see if that’s why he had a left hyper. That was normal. So that’s not why he had this. But he had a lax or loose left inferior rectus. When it was hooked on the muscle hook, it was floppy. So that’s consistent with longstanding paresis. So in this case, the inferior rectus was resected, and that was combined with recession of the superior rectus, to improve his hypertropia. And then we have a second video of his head tilt test. So you can see there was our first one. Let’s look at it one more time. All right? So this is pre-op. And look how much left hyper he gets. All right? And now let’s look at his post-op video. After he’s had his inferior rectus resected. I’ve got it all ready. And here he goes. And his right tilt… You can see we’re not really getting very much left hyper now. So he appears to be significantly better, after that. All right. And that was… The covering of the three-step test is the main thing that I wanted to cover with you there. Let me get back to the PowerPoint. Oh my gosh. Black screen. What’s going on? All right. Not sure where those… There we go. Okay. All right. Which brings us to our next case. And our next case — we’re gonna mix it up a bit. So this is from Dr. Jacoby. Friend of mine in South Africa. And this first case is a 7-year-old male. This third case, rather, is a 7-year-old male. And this patient’s been noted to have abnormal eye movements since birth, but is otherwise healthy, and has always had a relatively normal head posture, but it’s been noticed by the family that there’s a shooting upward of the left eye, when the patient looks to the right. So we have what appears to be an upshoot. So let’s take a look at this patient. All right. So… Back up to our search. And this upshooting patient is 25252. I’m gonna open that. And also let me see if we have any new questions. I have nothing pending right now. So I’ll get back to the case. And 25252. Let’s open this one. Take a look at this patient’s motility. All right. So 7-year-old boy with an upshoot of the left eye. Present since birth. And looking at the motility diagram here, you can see that the right eye has all zeroes, which means normal motility. And on the left eye, we have some abnormalities of the medial rectus and the lateral rectus, minimal abduction and adduction. So we’ll want to be looking at that on the motility grid here. Primary position… Always look there first. That looks pretty good. Let’s make a larger picture there. So his primary position — maybe he’s got a little bit of a head tilt. But no real apparent strabismus there. That looks pretty normal. He clearly has an abnormality here on left gaze. So he’s looking to his left. And you can see that the left eye does not abduct. All right? So we saw that on the motility grid. He has relatively limited abduction. Goes a bit past midline. I might give that a -3, let’s say. When he goes the other direction, in right gaze, his left eye just about disappears. Let’s take a nice look at that. So here, right gaze, again, he maybe goes a little bit past midline, but mostly what we’re seeing is that eye is rotating upward. He’s getting a large upshoot. His other positions — up and to the left — straight up — let’s go down to the right. It’s not adducting very well. Not depressing too well. And then downgaze… It’s a little bit of a divergence there. And then down and left… Not too grossly abnormal. Maybe not completely full on the left side. So an interesting upshoot here in right gaze. And then the limitation of abduction and adduction. Let’s go back. To our next poll question. So the third poll question. Looking at the motility photos of this patient, what do you feel is the most likely diagnosis? Is this a third nerve palsy with multiple cranial, multiple extraocular muscles involved? Is this a fourth nerve palsy giving this big upshoot here, is it a sixth nerve palsy, giving the limitation of abduction, or is it a Duane syndrome? And our audience is voting. And we have — nicely done here. So we have 89% of you believe that this is a Duane syndrome. And of course, there are different kinds of Duane syndrome. And this one has deficiency of both abduction and adduction. Which is consistent with the type III Duane syndrome here. And now this large upshoot. Well, why… These upshoots are really interesting. It’s not inferior oblique overaction. Although it looks like that. These upshoots really have more to do with tightness of that lateral rectus. So here you can see he’s not too anophthalmic on the left eye. Maybe a little bit. But look at how the left eye is rolling up as he looks to the right. And what’s happening is that — I’ll come off the screen share here for a second — what’s happening is that the lateral rectus is really tight. And so you’ve got the ball of the eye and then a very tight lateral rectus. And so it’s almost like you’re taking a ball and pushing it against a string, or a wire, rather than something spongy, like elastic. So normally the muscles are elastic. And when the eye gets rotated, the globe gets rotated against them, it just kind of stays in there. But when that lateral rectus is really tight, and the back end of the globe rotates around, it has to roll up or under that really tight muscle. So that’s what’s giving those upshoots and downshoots, the restriction caused by that tight lateral rectus. And so that’s why what we do with these is a little bit different. Let me go back to my screen share. And the way to eliminate these upshoots and downshoots in Duane syndrome is to reduce that tightness and that narrowness of the title lateral rectus. And so what I’d like to do is what Dr. Jacoby himself was suggesting might be a good idea. And that’s a Y-splitting of the lateral rectus. And what you do is you basically — before you put sutures in and disinsert the muscle, I just kind of slide a Stevens hook right in here, in the middle. To get about half of the muscle width, and you just kind of split that. So let’s see. Let’s go to the whiteboard. And let’s clear this out. All right. So you have your… Your lateral rectus. Still on the globe. And what I do is I just reach underneath it with the Stevens hook, and just kind of poke through it, right there, right behind the insertion. Once I’ve poked through it from the underside with the Stevens hook, then I run the Stevens hook forward and backward, pretty much as far as I can, to create a cleft in the muscle fibers. Once you’ve created that cleft, a lot of times you have to cut it all the way to the insertion here with a pair of Westcott scissors. So you haven’t disinserted anything. You just made a division in that lateral rectus, as far back as I can. Then I take two sutures, instead of one, I’ve got two sutures, and then disinsert that, and then that lets you get back to being able to split that muscle. I’ll get my screen share back here.
>> We also have a question, doctor.
DR NEELY: Yes. Let me go to that, as soon as I can… Okay. Let me open up the question here. So the question is: How much to resect the inferior rectus and recess the superior rectus in inferior rectus palsy case? I don’t know if that’s something you can say there’s an absolute answer for. It’s one of those where, normally, when we operate on healthy inferior rectus and superior rectus muscles, you kind of expect to get 3 prism diopters of change per millimeter per recession or resection. It’s kind of a 3 to 1 rule. But that’s not gonna apply if you have a paretic muscle. It’s also not going to apply if you have a tight muscle. So in thyroid cases, we might expect to get 4 prism diopters of change per millimeter per session. So I think it’s difficult to give you a set answer. And that’s one of the things where the art of this comes in. But what you do know is that when you have a paretic muscle, you’re going to have to do much larger amounts of resection. So a 5 millimeter resection on a paretic muscle on the inferior rectus is probably not going to be sufficient. But if you’re ever in doubt, then you don’t do both of them at the same time. You do your large resection on the inferior rectus in that case, and then you can go back and add a large recession of the superior rectus later. So no answer to that. But just be aware that you’re going to get less effect when there’s a paretic muscle and you’re going to get more effect when there’s a restricted muscle. I’m just going to close that. And then go back to our screen share. All right. So when you do these Y-splits — I usually will recess these a little bit. I think when you’re splitting the muscle like that, you’re probably also tightening it some. So even if I don’t need any primary position correction, I will recess that a little bit. A lot of these patients can be exotropic, and so you’re frequently combining this with a recession of the lateral rectus anyway. And we’re at about 45 minutes now. Let’s go on to our next case, I think. The last couple are shorter in general. This is another case from Cambodia, from my friend Dr. Khauv. 8-year-old female with a history of prematurity. 1 kilogram birth weight. This patient has head tilt to the left, also been noted to have exotropia on upgaze, relatively normal alignment in downgaze. But let’s focus on the head tilt next. So let’s launch our next poll question, relative to the head tilt. Head tilts are always interesting. So what are the ocular conditions that you have to think of when there’s an abnormal head posture or head tilt? Nystagmus, number one, Brown syndrome, number two, superior oblique or 4th nerve palsy, or all of the above? And of course, as you’re voting, I think we’re all going to agree… That the question is probably… The answer is probably all of the above. Right. So everyone’s on the same — in the same frame of mind with this. These are all things that you have to consider. You have to go through these diagnostic possibilities. Let’s open that case up. All right. So that’s 25088. Now, of course, when there are head tilts, the most common thing is a superior oblique palsy. 90% of the time, when I see someone with a head tilt, it’s because they’ve got a superior oblique palsy. All right. And this patient — looking at her, again, looking at the primary position, it doesn’t look too bad here in the primary position. Maybe she’s got a little bit of a right hyper, looking at her corneal light reflex. Downgaze — it was mentioned that she was pretty good in downgaze. So let’s look at that. Yeah, she looks excellent in downgaze. And then it was mentioned that she had exotropia in upgaze. So there’s a preview. Let’s go to the larger image. She’s got a moderate size exotropia in upgaze. So when you see exotropia, Z-pattern strabismus, so she has more exotropia in upgaze. Z-pattern strabismus. A lot of times we see that in conjunction with inferior oblique overactions. Let’s look at her superior obliques first. So down and to the right looks okay. Down and so the left looks okay. Up to the right. I think I see a little bit of inferior oblique overaction on her left eye here. I think that this left eye is up a little bit higher than the right. And let’s look at up and to the left. And also, there is some right inferior oblique overaction here. Maybe a little bit more on the right. Maybe some asymmetric inferior oblique overaction. A right hyper… And assuming a left head tilt… And some right inferior oblique overaction on right gaze… Or rather, on left gaze — those are all things that make you start to think of a right superior oblique palsy. But she does have this inferior oblique overaction on both sides. So it’s possible she just has some asymmetric inferior oblique overaction. So let’s go… Back to our PowerPoint. Okay. And I see there’s another question waiting, and I will get to that in just a second. We’ve got this — again, I just wanted to touch on diagramming motility, because there are two different formats for diagramming motility. This patient has mild to moderate inferior oblique overaction. And you can see some of these use these H diagrams. This is what I use in my office. And other people use kind of what looks like an asterisk or star. But they’re delineating the same thing. So each termination of a line is the primary field of action of one of the extraocular muscles. Superior rectus up and out, lateral rectus down to the side, inferior rectus down and out, inferior oblique up and in, medial rectus down and in, and then this is just straight to the side. Most of this is subjective. A little bit of overaction is +1. A moderate amount, like our patient has, is +2, +3 is more than that, and a lot of times, when you have +4, the eye almost disappears. Like the Duane syndrome case. The upshoot we saw with that. While that’s not inferior oblique overaction, the eye just really takes off. If they still show the sclera, that’s -1, if they can’t get to midline even, that’s -4. And everything in between. Just to show you what the motility diagrams are. So you can use it in consultations. When the obliques are normal, a lot of times in this case, you have a little bit of XT. And we use that mnemonic, MALE. Medials get shifted to the apex of the pattern. We have a V pattern. The apex is the point. If you’re working on the lateral rectus muscles, then the lateral rectus gets shifted to the empty space. The empty space on a V is the open end of the V, so the laterals will be shifted upward. However, our patient has a little bit of inferior oblique overaction, so we have to do something with the inferior obliques. Preferably recess them, do a myectomy, or we can do an anterior transposition, which I tend to reserve for those cases with associated vertical deviation. Now, our patient had a right hyper of 15. So there’s a fair amount of asymmetry in what the primary position deviation is. It was worse on left gaze and right head tilt. Some might say — okay, that’s more or less like what you would see with a right superior oblique palsy. I’m just going to weaken that right inferior oblique. And that would be okay. Certainly in recession or myectomy of the right inferior oblique would take care of 15 of right hyper. My concern would be since we see some left inferior oblique overaction, we might unmask that and come back with a left hyper, postoperatively. So I might choose to do bilateral left inferior oblique weakening. You can do asymmetric resections, more on the right than the left, or myectomy on the right, resection on the left. Various ways to accomplish that asymmetry. Some would say I’m just gonna do a myectomy on both sides. It’s self-adjusting and takes care of the right hyper, and I don’t have to do it asymmetrically. So different schools of thought as to how you can go about this. Let me go back to the question that is in the queue. And then we’ll — a couple questions up here. First question has to do with the Duane syndrome cases. How further can I incise the lateral rectus? Well, once the anterior portion of the lateral rectus is easy to split — this question is how far back can I divide it? Well, what I don’t do is I don’t pass scissors back there to extend the division posteriorly. But I think the easiest thing is just to slide the muscle hook back. And you’ll feel that at some point, especially as you get closer to posterior Tenon’s exit, the muscle hook doesn’t slide anymore. So you’re really not dividing the entire muscle. You’re dividing the anterior half of the muscle. And that’s why it’s a Y-split. So we’re doing a Y-split, not a V-split, of the lateral rectus. So just try to slide it back until you feel enough resistance that you feel like you should stop. All right? The next question is from Dr. Gabriel. In Duane, are they the same parameters of tight lateral rectus recession? So if I’m recessing a muscle for a Duane syndrome, do I use the same formula that I would for exotropia normally? No. I would be more likely to use numbers that would be what I would expect with a thyroid case. So in thyroid cases… You expect larger amounts of change, per millimeter of recession. And again, there are no tables for this. But if an eye is… One way to do this is if an eye is restricted, and you can’t get it to the primary position, then simply disinserting the muscle, pulling the eye in a primary position, and reattaching the muscle in that position is one way to handle either Duane or thyroid cases. But just know that you’re going to get a larger amount of effect. And another question about how to grade an inferior oblique recession. Having to do with this most recent case… How do you grade an inferior oblique recession? Well… A standard or classic 10 millimeter recession would be pulling the muscle… Let’s go to the whiteboard. I think that’s easiest here. All right. So grading inferior oblique recession. That’s a good question, because it comes up. And let me close out the question. And let’s clear this. So first of all… Here’s our cornea. And I’m gonna draw — this is gonna be the right eye. And this is gonna be the inferior rectus. And this is gonna be the lateral rectus. Not a very good L there. Okay. And the inferior oblique normally runs about 8 millimeters posterior to that, and down this way. That’s the normal course of the inferior oblique in the right eye. If I want to recess this inferior oblique 10 millimeters… So it’s gonna be from there, to there… Let’s say… I don’t measure it. Okay? And we use landmarks. And so if I want a small or moderate recession, of the inferior oblique, and this is the inferior oblique, I measure back 1, 2, 3 millimeters, and then over 1, 2 millimeters from the inferior rectus corner. And this is where I sew the inferior oblique on. So now the inferior oblique is here. So that’s the estimation technique we use for a 10 millimeter recession. Now, if you want to do a larger recession, that’s probably not very good there. You want to do a larger recession, of 14 millimeters, then we have the inferior rectus, and back here is the vortex vein. Right along the posterior border of the inferior rectus. Okay? That’s the inferior rectus. And so if you just disinsert that inferior oblique and sew it on, straddling that vortex vein… This is now about 14 millimeters. So that’s straddling the vortex vein — is about a 14-millimeter inferior oblique recession. Which is about, I think, the same effect that I do when I do myectomies. So I don’t often do 14 multiple recessions very often. I’ll just do myectomy. Because once you sew that inferior oblique here, you’re not gonna reoperate on that. As soon as you hook it, you’re gonna tear the vortex vein. It’s easier to do a myectomy. The muscle ends up here anyway, when you do a myectomy, even though you’ve chopped out 10 millimeters or so of the muscle. So that’s how you grade it, 10 or 14 millimeters. These things are very approximate, so there’s not a big reason to measure them precisely. I think sometimes we get carried away, breaking stuff down into half millimeters. Or I’ve even seen people do quarter millimeters. That puts us right at the top of the hour, so I think I’m probably going to bypass the last case here. And… Okay. There we go. All right. So again, you know, these are all complex cases. And there are never single answers to complex cases. And I think that’s something important to keep in mind. What’s important is that you think about them logically, and you look for the right thing. You know, if you see a head tilt, and the chin’s up, then you’re gonna look and see if the muscle away from that position is paretic or restricted. Try to make all the pieces of the puzzle fit together. Know how to do three-step tests. Know how to do traction tests. For purposes of discussing cases with other people, know how to grade the motility diagrams. And give prism diopter measurements. It’s easier to give people advice if you have some basic measurements. And they don’t have to be exact, and no one’s going to grade you on these. But it’s nice to have a primary position, it’s nice to have left and right gaze and up and down gaze in certain cases. And head tilt. It’s relatively uncommon that you need all nine diagnostic positions measured, but it’s nice to have a few measurements to go by. Especially in these incomitant cases, like we’ve seen today. These are obviously complex. Again, stay tuned later this week. You’ll be seeing the revised template for the consult case, where things are condensed, and presented in a much more efficient, and I think clean manner. I think it will facilitate you submitting cases, and it certainly will facilitate reviewing cases at a later date. And don’t forget that you can review cases. You can search cases. Use the search function. In any case that’s been closed and opened to public viewing, you’ll have access to that case. I have a couple questions coming in. I’m going to look at these before we wrap things up. First question is: How do you differentiate between bilateral, asymmetric inferior oblique overaction, and bilateral asymmetric superior oblique palsy? So how do you differentiate inferior oblique overaction from superior oblique palsy, basically? Well, in some ways, they’re the same thing. I guess the big difference is, when you have a superior oblique palsy, say something acquired from a head trauma, then the superior obliques are usually very, very weak. And that’s when you pick up lots of excyclotorsion. And that’s why double Maddox rod testing is so critical. Because bilateral superior oblique palsies are usually gonna have more than 10 degrees, maybe even more than 15 degrees of excyclotorsion, and a lot of times it’s worse on downgaze. The case that we had, we didn’t have any torsion measurements. But there was no history of trauma or other abnormality. And the amount of inferior oblique overaction was modest. And it was with a V-pattern exotropia. A lot of these things are kind of just mild inferior oblique overaction. Is it overacting because the inferior obliques are pulling too hard? Or is it overacting because the superior obliques aren’t pulling enough? Because of orbital asymmetry or orbital dynamics? We don’t really know that. it probably can be multifactorial. But basically that’s why torsion, I think, is so critical. Because if someone has 15 degrees of excyclotorsion, we don’t operate on the inferior obliques. We do something that’s going to be a little bit more torsion-appropriate. Next — I’ll make this the final question before closing things out. Can inferior oblique after myectomy reattach and act an undesirable action? So after we’re cutting a piece of the superior oblique out, can it reattach? Yes, and we expect that it does, in all cases. Sometimes it reattaches in a position that’s still producing a significant effect. When you go back and reoperate, you can always find an adherence scar. Where the inferior oblique is back on the globe, or there’s a band of scar tissue connecting the globe to the inferior oblique. So if I have someone with inferior oblique overaction, particularly if it was a bilateral or asymmetric, I’ll go back, explore the inferior oblique, and remyectomize it. Some people will take a suture like an 8-0 vicryl, and suture across the posterior Tenon’s capsule. And then you suture the posterior Tenon’s capsule opening closed, so that that inferior oblique doesn’t return to the globe and form scar tissue there. So that is another way that you can do that. But always, if there’s residual action, go back and explore it, before you do another surgery, to help with that hyper. Because more often than not, you’ll find a little adherent band that you can take care of. So again, thank you for everyone’s questions and your time. And again, this and all the other webinars are available, recorded, at the Cybersight homepage. And take a look at the list of upcoming webinars. There’s some really exciting, great variety of things coming up, and I wish everyone a pleasant day. Thank you.
June 19, 2017