Objectives of this lecture are:
- To learn to diagnose vertical strabismus
- To differentiate “A” from “V” patterns
- To recognize and manage Dissociated Vertical Deviations – DVD
- To learn the surgical anatomy of the inferior oblique muscle
Lecturer: Dr. Rudolph Wagner, Rutgers New Jersey Medical School
(To translate please select your language to the right of this page)
DR WAGNER: I’m gonna speak on — today I’m gonna talk a little bit more about vertical strabismus, which is something that we did today. And then we’re gonna see a little bit about it. Okay. So we have the pretest. Everybody’s favorite thing. And what I have here — let’s read the first question, okay? Surgical correction of A and V patterns always requires surgery on the oblique muscles. In other words, if you have an A or V pattern, and you need to correct it, you always have to do something to one of the oblique muscles. Or are there other ways around it? So 50% say yes, and 67% say no. I guess the reason the question is kind of a trick is that you don’t always have to do it. Sometimes you can do transpositions of the muscles. In other words — the thing is, if you have an A pattern, and you have an exotropia, you can move the lateral muscles to the base of the A, lower. If you have a V pattern, with esotropia, you can move the medial insertion down. I’ll get into that. But that’s — so sometimes you don’t have to. Good. Now, some people were at lunch, I know, during the second and third procedure. But there’s at least three people in this room that, if they get it wrong, I’m not gonna be very happy. So in a 14-multiple recession, the inferior oblique tendon is attached where? Where do you attach it? Answer A is just anterior to the inferior temporal vortex vein. B is at the lateral insertion of the inferior rectus muscle, or C, at the lateral rectus muscle insertion. And what do we think the answer is here?
>> C is not correct. If you watched the operation, we did two 14-millimeter recessions of the inferior oblique in the last case. And we put them both just anterior to the vortex vein. We did two cases of the anterior… Of 14-millimeter recessions of the inferior oblique muscle, and we placed them just anterior to the inferior temporal vortex vein. Which is — A would be the answer there. I see. All right. And the third one. To correct a V pattern esotropia — in other words, a V pattern where the horizontal deviation is — the esotropia is greatest in downgaze, and least in upgaze — you can move the muscles — you can move the medial rectus muscles or the insertions of the muscles — and the answers are A, more posteriorly, B, downward toward the apex of the V, C, superiorly toward the open V, or D, is not to be moved at all. So… You can read that, right? Okay. So… As I said earlier, when we first started, in order to correct the V pattern, or to improve a V pattern, you can move the insertions of the medial rectus muscle down, toward the apex of the V, if it gets close together, or… Well, that’s what you would do. If it was an A pattern, you would be moving them up, toward the apex of the A. And you can, at the same time, of course, you can recess the muscle, but also change its insertional point. So you can adjust for it that way. So the objectives of this lecture are to learn to diagnose vertical strabismus, to be able to differentiate an A from a V pattern, to recognize and manage dissociated vertical deviations, or DVD, and to learn the surgical anatomy of the inferior oblique muscle. So let’s talk a little bit about vertical deviations. First of all, you can have a vertical deviation that’s comitant or non-comitant. And what that means is that, if it’s comitant, it means that the deviation is essentially the same in every position of gaze. Whereas if it’s non-comitant or incomitant, it means that it’s different in different positions of gaze. And most of the time, when you have a non-comitant strabismus, it’s related to a paralytic strabismus. There’s a palsy of a muscle, or a weakness. So to look at them individually, usually when it’s incomitant, it could be a dysfunction or overaction/underaction of the superior or inferior oblique. Could be related to paresis or contracture of a vertical muscle. Or it could be mechanical restriction, like in thyroid disease, or trauma. Now… You have to understand what a true vertical deviation is, versus something like a dissociated vertical deviation. I like to separate them into two categories. Okay? So the true — vertical deviations usually are described according to the position of the non-fixating eye. So if I am fixating with my right eye, and my left eye is up, we’ll call it a left hypertropia. If I’m fixating with my right eye, and the left eye is down, we’ll describe it as a left hypotropia. But in a true vertical deviation, with the left eye fixing, using my left eye to look straight ahead, I’ll have a right hypertropia. That means my right eye will be higher. However… If you cover my left eye, and you then force me to fixate with the right eye, you’ll produce a hypotropia in the left eye. Right? Everybody understand that? If you can explain that quickly. You understand? It’s just a description. DVDs are different. DVDs — what’s happening — a simple way to look at it is: What’s happening in the one eye is not really related — it is related, but it’s not really related to the other eye. In other words, if I have a right hypertropia, and I cover my left eye, and the right eye comes down, you may not see any movement in the left eye, either up or down. Sometimes you’ll see it also come down. Then it’s a true double dissociated vertical deviation. But the point is: It’s not — you’re not gonna get a corresponding hypotropia in the opposite eye that has the hypertropia. So a primary overaction of the inferior oblique muscle would be in the category of a true hypertropia. Meaning that if you do an alternate cover test, you’ll have a hypertropia with one eye and then a hypotropia in the other eye. Things about it are — there’s no superior oblique muscle paralysis, with a primary overaction. It develops in two out of three patients with congenital strabismus or congenital esotropia. And there’s an overelevation of the adducted eye in… I think I wrote that wrong. There’s an overelevation of the adducted eye. It should say medial gaze. With the adducted — with the abducting eye fixating. So here are some examples of it. It’ll make it a little bit easier to see or understand. This is a child with no primary gaze deviation at all. The eyes look like they’re aligned okay. And here there is a bilateral overelevation of the inferior obliques. So you can see that in the adducted position, there is overelevation of that eye. So it’s a true hypertropia in that left eye. And I mentioned this yesterday, but the way you determine that it’s an overelevation is I look at the inferior limbus and compare the distance from the lid in one versus the other, to see that there’s a true overelevation there. So the usual management of the inferior obliques, if you need to weaken them, is either to recess, as I did today, you can disinsert the muscle, just cut it loose, or you can do a myectomy, where you actually take a portion of the muscle, remove a portion of the inferior oblique muscle. Now, anteriorization of the inferior oblique is another procedure to weaken the muscle, but in this case, you would transpose the muscle, you move the muscles, insertion of the inferior oblique, to the lateral margin of the inferior rectus muscle. And I usually use that for cases that have a combined inferior oblique overaction and a dissociated vertical deviation. So the inferior oblique inserts at the inferior margin of the lateral rectus muscle. It originates in the maxillary bone, in the floor of the orbit. And passes below the inferior rectus, and then inserts right at the inferior margin of the lateral rectus. So here’s a picture — an example of the inferior oblique muscle. An incision was made, and it’s already been isolated, and it’s already on sutures. This is the inferior view. So that’s the inferior rectus muscle, hooked below the conjunctiva. So this is a view as if you’re looking at the patient, where this is the inferior and that’s the superior. Not exactly — not really the surgical view. But this is the inferior rectus muscle. Here’s the inferior oblique muscle. And it’s being attached along the margin of the… Along the margin of the lateral rectus muscle. And this one actually, if you put it farther back, if you go 14 millimeters back from the insertion, that’s what we call — or put it towards the vortex vein, excuse me — that’s a 14-millimeter recession. Doesn’t really show on this picture. It’s better in the case we did today. So in an anteriorization, the muscle is placed just at the lateral margin of the inferior rectus muscle. And when you do this procedure, you have to be careful. You have to be very close to the inferior rectus. You don’t want to displace it too far laterally, because it changes the function of the muscle, and it produces — it could not work as well, and it could also produce something called antielevation, which means that you — what happens is you actually can’t elevate — it actually looks like your opposite eye — in your opposite eye, it won’t elevate in the adducted position. It’s hard to describe it. I’ll describe it later. So the 14-millimeter recession is where you actually locate the vortex vein as it exits from the sclera. And you then attach and there’s the vortex vein, and you put the — you insert the muscle just on both sides of the vortex vein, if you can visualize that way. As close as you can to the inferior rectus muscle. And that’s a 14-millimeter recession. Now, the other way to recess it, if you want to do more of a moderate one, you can recess it 2 millimeters over and 3 millimeters back from the inferior rectus muscle insertion too. You know, that’s a more moderate recession. And if you do an anteriorization, if you place it too far anterior, where the inferior rectus muscle is, you can actually — you make it a depressor of the eye and produce a hypotropia. Especially if you do it only in one eye. So you always want to do this in both eyes, in most cases. And I mentioned yesterday, you could take advantage of that. I had a case where I had a damaged inferior rectus muscle, and in order to produce a vertical movement in that eye, I did a transposition of the inferior oblique muscle. Anterior to the original insertion of the inferior rectus muscle, and it actually helped with the depression, to correct the vertical, the hypertropia that was there. So if you have a dissociated vertical deviation, neither eye will refixate, as I said earlier, with an upward movement, whether adducted, abducted, or in primary gaze position. So you never have a hypotropia in the opposite eye. So the way you measure it is: You have to hold the prism only in front of the deviating eye. And you do your alternate cover test, but you basically are only observing what’s going on in the eye with the prism in front of it. So I showed this yesterday. This is a DVD. The patient is ortho in the primary position, but you could cover one eye and you can induce it, and you can see that the left eye is a little higher. And that’s not in the adducted position. That’s in the straight ahead position. Here’s — like I showed some of this yesterday too — but this is actually a patient with a DVD and an inferior oblique overaction. Ortho in primary position. Right hypertropia in primary position. And this 6-year-old had a recession for congenital esotropia, but ended up with both the DVD and overaction of the inferior obliques. So here you can see there’s a right hypertropia in primary gaze. But a right hypertropia greater in left gaze, which is — this is due to the inferior oblique overaction. This is due to the DVD. So you have to correct both. And that’s where we consider anteriorization of the inferior obliques, in order to — you can correct both in that case. If you don’t have to do an inferior oblique recession, or you have it unilaterally, like in an eye that doesn’t see as well, sometimes I’ll recess the superior rectus muscle alone in one eye. If it’s not as good, if this is a better-seeing eye, I might do that. So how do you diagnose and manage A and V patterns? So the clinical features of A and V patterns are: The horizontal deviations that change in upgaze and downgaze. The horizontal deviation changes. And you can have an A pattern with a horizontal deviation that’s more convergent in upgaze, or a V pattern where the eyes are more convergent — or more convergent or less divergent in downgaze. Just think of the shape of the letters. You could also have what we call an X pattern, which is not really common, but in patients with longstanding exotropia — usually they’re adults that have had exotropia for a long time — when you check them, you have them go up in lateral gaze, and it often looks like they have overactions in both the inferior obliques, and then if you go down, it looks like they have overaction in the superior obliques. And we call it X pattern. And usually it’s just related to the lateral rectus muscle sliding a little bit, and you — and most of the time, if you just correct the horizontal deviation, that goes away in the X pattern. So most people consider an A pattern to be significant if there’s a 10 prism diopter difference between up and downgaze, and the downgaze is 25 degrees, but if there’s a 10 prism diopter difference between up and down, they would consider that a significant A. Whereas V — it’s not usually considered significant unless it’s a little bit more. 15 prism diopter difference or more between up and downgaze. And you can have a V pattern with an esotropia, V pattern with an exotropia, A pattern — so you can have all these patterns with a horizontal deviation. So back to the causes of A and V patterns. They’re usually caused by oblique muscle dysfunction, inferior oblique overaction with a V. And superior oblique overaction with an A. And also they can be caused by the horizontal muscles and different gaze positions. There sometimes is an association with A and V patterns with figuration of the shape of the orbit. In the person. The eyelids too. So upward and downward slanting of palpebral fissures, depending on the direction of the lid and the orbit, will sometimes alter the forces in the muscles, and can produce A and V patterns. And, for example, certain medical conditions, like the craniofacial disorders, like Apert and Crouzon’s disease — they frequently get V patterns, and they look like they have inferior oblique overaction, but it may be from a variation in the insertion of the muscles, of the horizontal muscles. And this condition, spina bifida, or meningomyelocele — you know what that is, right? When they have a birth defect, where they have an open — the spine is open in the back. When the babies are born. They usually have hydrocephalus, and they’re usually paralyzed. Some are. Some have problems with walking. It’s also associated with A and V patterns, and it’s really interesting, because — well, say the first part first. Just what I said. That it could be — well, I’ll keep going. So I used to have a clinic that we would see many, many patients with spina bifida. Fortunately it’s not as common as it used to be. And someone remarked that they kind of looked similar in appearance, facial characteristics, and it didn’t matter if they were Asian, you know, White, Black, different ethnicity — it didn’t make any difference. They all looked similar in the shape of their faces. We found that they had — the palpebral fissure on each side were directed sort of in an upward slanting of the lateral palpebral fissure. And they often had A and V pattern. So we thought that might be a cause of — the orbital variation could cause the muscle problem, the extraocular muscle problem. But most of the time, the A and V patterns are just caused by variations with the overaction of the oblique muscles, more commonly. So here’s a boy who has — when he wants to look at things, he keeps his chin down like this, to look straight ahead. So in this position, with his chin down, his eyes look like they’re in good alignment. When he looks down, he has an esotropia. In downgaze. You can see in primary gaze, it’s a small esotropia. When he looks down, it’s a larger esotropia. He also switches fixation. But the esotropia increases from upgaze to downgaze. So you would expect to see overaction of the inferior obliques in this patient, because it looks like a V pattern. And there it is. You can see overelevation of the adducted eye in each gaze. Lateral gaze. So management of V patterns would include recessing the medial rectus in each eye for the primary deviation. It’s a V pattern esotropia. Perhaps weakening the inferior oblique muscles. You may need to vertically displace the horizontal rectus muscles 1/2 to 1 full tendon width. Especially if there’s no or minimal oblique overaction. And you do that — you displace them toward the vertical gaze, where the convergence is greater. Or divergence is less. Explain that, right? Now, sometimes… Sometimes you have to… Not that often, but if there’s a really big difference between, like, a 25 prism diopter difference between upgaze and downgaze, and the inferior oblique overaction is not really a lot, sometimes you have to weaken the inferior obliques and also at the same time recess the medial rectus muscles and place them inferiorly, to correct the esotropia in downgaze. And this is basically drawings of what we kind of did today, to work on the inferior oblique. We did elevate the eye in adduction, make an incision inferiorly, get through the Tenon’s membrane. You can see that. And then you put a hook under the lateral rectus muscle, and you then put another hook inferiorly. You expose the inferior temporal quadrant, and then this is what I was trying to show you, with the small hook, to go along — I like to put the hook down and then turn it out, and you hook the muscle. It’s a little bit easier. And this is just dissecting around it, and then isolating it. And this is showing how you can put your sutures through, and then cut it off. This is really a little bit farther away from where we usually do it. But you can see — I got lost here a little bit in this picture. Yeah. We like to cut it close to the insertion. In this case, we put the sutures in after we cut it. You can do that, because, like I said, there’s not much action. It doesn’t retract. And then you can either attach it, like I said, for an anteriorization, right next to the lateral rectus — inferior rectus — or you can put it back farther for the recession. Now, A patterns have the opposite, where the eyes are the most convergent or together in the — in upgaze. They’re not as frequent as I see in V patterns, but when I do see them, they usually are in kids that probably had a strabismus, but it wasn’t corrected early, and as they get older, it seems to develop — I have a lot of — like, I see a lot of A patterns in teenagers. In older people. I don’t see it as much in three-year-olds or four-year-olds. I think it’s just a time-related thing. So you can see here ortho and primary. A little bit of an esotropia in upgaze. But when you look down, a big exotropia. Here you go. Here’s a big overaction, on the right superior oblique muscle. And you can compare the superior limbus, and you can really see the difference, right? And then if we go in the other direction… What happened here? You can see it down in this position. You can see it also. Something got… I don’t know what happened here. I must have made it wrong. That’s supposed to be in the middle. That’s supposed to be there. But it doesn’t matter. You can see — the whole point is that you see the overdepression of the adducted eye in adduction. Overdepression. That’s what superior oblique overaction looks like. And the management is usually… You need to weaken the superior oblique muscle. You can do it different ways. Bilateral tenectomies, you can use a superior oblique expander, which is a retinal silicone band that you put in there. You know what I’m talking about? You extend it. And the reason that we get concerned about the superior oblique is because of this: If the patient has binocularity, in other words let’s say that there’s some position where they’re ortho, and if you measure their stereo, and they have good stereo acuity, you’ve got to be very, very careful when you operate on the superior oblique. Because you’re much more likely to produce a torsional defect after you weaken the superior oblique, if they’re binocular. So you don’t see as much surgery on the superior oblique. Now, if they’re not binocular, you don’t have to worry as much about these torsional changes, because you actually — when you cut the superior oblique, or you do a tenectomy, you can get — you can really produce a superior oblique weak palsy in some of those patients, and they can get torsion. But what I do now — I don’t like to do tenectomies, because I just get nervous about it. So I started doing — I do sometimes use a silicone band, where you extend it. But lately, I’ve been doing — it’s harder to do, but I like it better — I’ve been doing posterior tenectomies. In other words, the anterior fibers — you can start with this — the anterior fibers in the superior oblique are thought to be involved more in torsional movement, and the posterior fibers are thought to be more involved in vertical movements. So you can do a tenectomy, remove the posterior half or section of the superior oblique tendon, leave it still attached anteriorly, and that can help with these A pattern conditions. You got it? Does everybody understand that? You know, I don’t operate on the superior oblique very often. It’s the least common one that we’ll do surgery on. And you have to be careful with it. Of all the muscles, you have to be the most careful. But the posterior tenectomy — I don’t think I have a picture of it, because it’s something I started doing recently. But it works better than some of the other things. But it’s a little bit harder, because you have to spare the tendon. But anyway… Just bear in mind that it’s… With these A patterns, they’re not as easy to deal with as the V patterns are. And this is just showing the direction of displacement for the medial rectus muscle in an A pattern, and lateral, in a V pattern — A pattern. And you can see the laterals go up. In the V patterns, the medials go down. So that’s what you have to remember about the displacement. Here’s another V pattern esotropia. This is a baby with — looking down, you can see the eyes are much more esotropic than when he looks up. Not too much in primary position. And many times, if they have no deviation in primary position, I don’t necessarily do anything. I mean, I might observe them and see if it changes, and then do the surgery. There’s another — showing very well the overaction of the inferior oblique muscles in both eyes. And here’s overaction of the right inferior oblique. Okay? And we talked about this already. About the association of the DVDs and the inferior oblique overaction. So that’s it. So our objectives were to learn and diagnose vertical strabismus, differentiate A and V patterns, and recognize and manage the DVDs, and learn a little bit about the anatomy of the inferior oblique, and then something about the superior oblique. So hopefully you learned something from this. And I think you have to just read more about it, and try to continue to learn on it. But once you’ve involved the vertical surgery, it’s very useful to know how to do these, when to operate on these cases.
>> Maybe you’ve written on the DVD with the overaction of inferior oblique — without DVD — DVD, without —
DR WAGNER: Without inferior oblique overaction?
>> Yes, because they had a question.
DR WAGNER: What do you do in cases where you have — only DVD, with no overaction of the inferior oblique? So in those cases, if there is significant bilateral DVD — in other words, you can get a hyper in either eye, when you do your alternate covering — I sometimes still will do an anterior transposition of the inferior oblique. Sometimes. Okay? The other option is to just do bilateral superior rectus recessions. And that’s normally — if it’s a bilateral case, that’s normally what I’ll do. If it’s unilateral, and there’s very poor vision in the eye that has the DVD, then I’ll probably just do a superior rectus recession in that eye. Okay. So I think that really concludes the lecture. I think — they wanted me to go through this again quickly, for people who are taking it — watching this remotely. Okay? So the answer to these questions: Surgical correction of A and V patterns — surgical correction of A and V patterns always requires surgery on the oblique muscles. Does it always require it?
DR WAGNER: We learned that, right? I don’t know how many responses… And then we talked about — in 14-millimeter recession, where do you put it? Okay, good. So we got 4 people said no. Good. You learned something. Where do you put the inferior oblique? Where is it attached? Just anterior to the inferior temporal vortex vein, at the lateral insertion of the inferior rectus, or at the lateral rectus muscle insertion? Let’s see if we get a response there. And we have 100% of the two people said just anterior to the temporal vortex. I know. It’s online. I know, I know. You all know the answer. And then the third one is: To correct a V pattern esotropia, the medial rectus muscles must be moved… Where? More posteriorly, downward toward the apex of the V, experimental toward the open V, or not moved at all? Everybody here knows the answer to this question. But we’ll see what our remote observers or students think about this. Okay. We’re gonna find the answers. And we have…
DR WAGNER: Very good.
>> Yes, very good.
May 31, 2017