This lecture will introduce the fundamental concepts needed to perform successful rectus muscle strabismus surgery, including surgical techniques and planning for horizontal and vertical rectus recession and resections, vertical offsets for A- and V-patterns and small hypertropias as well as full and split-tendon transpositions for paretic strabismus such as sixth nerve palsies, monocular elevation deficiencies and partial third-nerve palsies. Both limbal and fornix-based incisions will be demonstrated with diagrams and videos.
Lecturer: Dr. Daniel Neely
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DR DANIEL NEELY: Well, hello, and welcome to the third installment of our Orbis webinar series. I’m Dr. Daniel Neely. I’m a long time Orbis volunteer faculty, and in addition to that, I’m a professor of ophthalmology at the University of Indiana School of Medicine, where I practice pediatric ophthalmology and adult strabismus. In today’s hour, we are going to start covering more advanced strabismus. This is the complex strabismus lecture. You recall that last time we discussed the fundamentals of strabismus. And that was including instrumentation, basic techniques, things like rectus muscle recessions and resections for both horizontal and vertical difficulties. So today we’re going on to the more complex things. And one thing that should have been obvious to me as I put this together was that complex strabismus is, in fact, rather complex. And there’s a lot of material here. So I anticipate this is likely going to end up being part one of a two-part series. Because what we really want to do is spend some time discussing these problems, taking your questions, and having an interactive process, as much as possible. And I really don’t want to rush through that. So please keep in mind you can use the question function, and those questions will appear with me. And as we kind of conclude each section, I will go through those questions and see which ones we might discuss all together here. I’m going to go on now to screen share the lecture. There we go. The music is tied to our title slide. And here’s our title slide for the presentation. So again, this is surgical management of complex strabismus. And we are gonna focus on the surgical management, the techniques that you need to use. You can spend a whole hour on each one of these subtopics, talking about Brown syndrome and evaluation of superior oblique palsies, but we’re really gonna concentrate on the surgical technique that we need in the operating room, and the planning that goes into those techniques in advance. Before we get started, we will go through our first poll question here. And the first poll question is: We want to know who you are. And we want all of you to know who is in our group today. And so the first poll question is: What is your position? And we want to know: Are you an ophthalmologist? Or are you an ophthalmologist in training, a resident, or a registrar, a nurse, perhaps, a technician, or other allied health professional? There may be some medical students in our group. Or you may be in a large group in a room with people from many different backgrounds. And that’s good to know too. That’ll help me tailor our discussion today. And it looks like that is going to be pretty easy. I’ll show you the poll now. And it looks like we’re pretty heavy on ophthalmologists today. And a few that are in training. So again, this is a complex topic, and we’ll tailor it towards that group in particular. Now, moving on, let’s first look at our course outline here. Well, complex strabismus covers a lot of things. We talked about rectus muscles last time. So we’ll start today by moving on to the oblique muscles. The inferior oblique, surgical approaches to that, the superior oblique, with both 4th nerve palsies and Brown syndrome, and then we’ll talk a little bit about the other cranial nerve palsies, and then get into Duane syndrome, which segues into restrictive forms of strabismus, thyroid myopathy, and then I want to also touch on the use of Botox and adjustable sutures. So you can see this is a lot of material. I’m expecting we’re probably going to get through this first column, more or less, but we’ll go as far as we can. And we’ll spend all our time discussing these issues, and then we’ll carry on the next time and get to the rest of it. And keep in mind that, should you miss something on any of these webinars, they are all recorded. They are available on the Cybersight website, so you can at any time go back, watch the webinar again, and it’s forever available to you. And also, a lot of the questions and answers will be available. We’ll post those alongside the video presentations. Now, the inferior oblique. Before we get into that, it brings us to our second poll question. I’d like to know what you do. We all have preferences. And we all have different ways that we’ve been trained. What do you do for the inferior oblique? What are you comfortable doing? Do you like to do recessions? Do you like to do myectomy? Do you do both, depending on what the patient’s condition is? Or are you just not really comfortable with inferior oblique surgery, and you choose not to do it at all? And I’ll bring up, now, the results of the poll. It looks like most of you have answered. There’s still some changing here. Myectomy — I’ll give you a hint here. Myectomy seems to be in the lead. I’ll bring this up. And… Now you can see the results of this. So the bulk of people are doing inferior oblique myectomies. That happens to be my personal preference as well. But I do do both. I do use recessions as well. And we’ll discuss why that is, why you might pick one over the other. And so going on, inferior oblique overaction. This is one of the most common things that we see in the clinical setting. Because it so frequently travels along with refractive esotropia and certainly patients with congenital esotropia. In this patient’s photos, you can see that as the child is looking to the left, the right eye, which is adducting, is shooting upward. And we can see the same thing on the right. Right gaze. The left eye, shooting upward. And again, that’s frequently associated with V pattern esotropia, and it’s a very common reason to need to operate on these patients. When we talk about V pattern esotropia, we are generally talking about a difference in the prism diopter alignment in the eyes that is 15 or more prism diopters different from upgaze to downgaze. So, for instance, this child — relatively straight in the primary position. You can see that the lines are going right through the center of the corneas. And if you can see the corneal light reflex — it’s right there. We can see they do have inferior oblique overaction on both sides. Right here and here. And any time you see that, you definitely wanna look for a pattern. I don’t necessarily measure every patient in all these positions, unless I start to see these kind of inferior oblique or superior oblique overactions. Otherwise, I pretty much concentrate on measuring in the primary positions. But here you can see we’ve noticed the inferior oblique overaction, so now we’re looking for a pattern, and we’re expecting a V pattern, and that’s what we see. Upgaze, the eyes are diverged, and in downgaze, they are more esotropic. And the difference from there is more than 15 prism diopters, so we have a V pattern. And this would be a perfect example of someone that I would probably quantify as having 2 to 3+ inferior oblique overaction. Now, that gets to be concerning for some people, grading that. It’s difficult to measure that. It’s really something that’s rather subjective. Much like dissociated vertical deviation is subjective. When you’re treating inferior oblique overaction, that degree of overaction is usually how I make my decision about what I’m doing. Our choices: Inferior oblique recession, inferior oblique myectomy, and then anterior transposition of the inferior oblique. And that’s an important topic for us to discuss. That is something that you most commonly see in the setting of congenital esotropia, but it can occur with other conditions as well. Inferior oblique recession is something that I tend to reserve for mild overaction inferior obliques. What I would maybe quantify as a 1+ or 2+. In this case, any time you’re doing something to the inferior oblique that’s a recession, you are simply moving it along its normal insertion course. So typically, the inferior oblique travels underneath the inferior rectus here, and then it inserts underneath the edge of the lateral rectus, about 8 millimeters back. So if you’re going to recess this, you’re just following that contour, and it could be anywhere in here. And typical recessions are anywhere — well, most commonly, I think most of us do maybe what we would call a 10-millimeter recession. And that means you’re gonna reattach the inferior oblique right about here. Now, rather than measuring this from the insertion, like we normally do, you can use landmarks to approximate this. Because it really is a gross approximation. This is not critical measuring. This is a muscle hook that is underneath the inferior rectus. And this is the inferotemporal quadrant of the right eye. And you can see the inferior oblique has been disinserted, and has a suture in it, and we’re simply gonna measure inferior 3 millimeters from the temporal corner of the inferior rectus, and then 2 millimeters temporal. And we’re gonna reattach it right here. And that is the equivalent of reattaching it right there. Okay? So that’s the easiest way to measure that, rather than trying to measure from the insertion. And that is called a 10-millimeter inferior oblique recession. Now, some people will do larger recessions. You can get up to maybe 14 millimeters of recession. That would be placing the muscle right here. That is about 5 millimeters back from the insertion of the temporal corner of the inferior rectus. Right about there is typically a vortex vein. So essentially your sutures are straddling that vortex vein. And that’s why I tend not to use this technique. To me, a 14-millimeter recession is relatively equivalent to a myectomy. I use it for 2+ and 3+ inferior oblique overaction. And it’s not really something you can go back and reoperate on, so I don’t see any benefit to doing it. If you try to go back and reoperate on a 14-millimeter inferior oblique recession, it’s right overtop of the vortex vein, and you have a very high risk of tearing that vortex vein. So I actually try to avoid that. I will go on and do myectomy in these cases. So that’s our 10-millimeter recession for mild inferior oblique overaction. I’m gonna just go back to the photo for a minute, so we can talk about grading. I would not do it on this patient. This patient is 2+, maybe 3+ inferior oblique overaction. Something like this I’m going to do a myectomy. So just to help grade that for you. Myectomy. Myectomy is a little more powerful than a recession. And why is that? Well, we’re removing part of the inferior oblique. We’re essentially removing anywhere from 8 to 10 millimeters of the inferior oblique. And we’re not reattaching it. We’re just letting it go. Now, does it retract and disappear like the medial rectus does? No. There are so many attachments between the inferior oblique and the inferior rectus here that basically it retracts and hangs out right here. So you can see it’s hanging out right there, and it’s gonna reattach to the sclera right there, and you can find that any time you reoperate on these. It’s adherent right here. So basically you can see how that ends up being equivalent to a 14-millimeter recession. It’s in that same position. Now, we’re only taking out 10 millimeters, because we’re leaving some stump over here at the insertion. I frequently use this not only in inferior oblique overaction, from V pattern esotropia, but a lot of times this is my go-to primary procedure for superior oblique palsies. And that will help correct about 15 prism diameters of vertical deviation that we’ll see when we move on to the next section. Here is a nice visual. The inferior oblique — give you some orientation here — this is the right eye. And right about here is the inferotemporal quadrant. This suture right here, it’s a black 4-0 silk suture — it’s right underneath the lateral rectus. So this is where the inferior oblique has been disinserted from. Right back in here. And it is now in the hemostat, after it was cut, just distal to the hemostat. And we are isolating this 10-millimeter section here. This is basically what we’re going to remove right here. And it’s right where it starts to go through the Tenon’s, and here’s some of these attachments that we talked about, where it starts to be adherent to the Tenon’s capsule and the underside of the inferior rectus. First hemostat that we saw — and now a second hemostat has been placed across, isolating this 10-millimeter section. And here I’m using a high temp cautery to just kind of remove that. I like this, because it cauterizes and cuts at the same time. You can do the same thing with scissors and a cautery afterward. So 8 to 10 millimeters is removed. And then we just let it go. Here you can see it’s retracted just down to the exit of Tenon’s capsule, but it doesn’t disappear. And that’s why it reattaches right here. So this is kind of a self-adjusting procedure. Now, we’re gonna look — talk about anterior transposition, and then we’re going to look at a video, which pretty much will represent all of these procedures at one time. Because the approach is the same. Anterior transposition is a frequently overlooked tool. And in addition to being useful here for inferior oblique overaction, it also helps control dissociated vertical deviation. There’s some indication — some articles out there — that would indicate this is actually more powerful than doing myectomy. That you get more correction from this. So keep that in mind. We can provide those references, if you’d like to see those. But my main use for this procedure is when I have dissociated vertical deviation. What’s that? That’s when we have an eye that is performing kind of a slow spontaneous upward and outward rotation, when the patient is inattentive, or perhaps they have an eye that doesn’t see as well. And so you get this upward, outward, and this excyclorotation. And it is usually bilateral. Frequently asymmetric. And it’s not there when children initially have their surgery for congenital esotropia. Usually this is something that seems to appear later on, when they are 3, 4, 5, and it will appear in about 90% of operated cases of congenital esotropia. So it’s a rather interesting condition. Here’s an example of it. Here we have normal, on the left side of the screen. This is just when they’re fixating with both eyes. And then we put an occluder in front of the left eye. And while it’s occluded, it drifts upward. And when we take it away, it comes right back down. So the only thing that’s happening is the left eye goes up and comes right back down. So normally, if you have a hypertropia, that’s the same thing as having a hypotropia on the other eye. You never see that with a dissociated vertical deviation. That’s where the term dissociated comes from. It’s on its own. So this is violating Hering’s law of yoke muscles. Now, the anterior transposition is… It does weaken the inferior oblique by moving it closer here to the inferior rectus. But you also then reattach it in variable positions. The classic technique is to attach it 1 or 2 millimeters right in front of the inferior rectus insertion. But you can also slide it back and put it back 1 or 2 millimeters. So there’s a range of grading this. It’s not clear if that makes a difference. Particularly if you do it asymmetrically. But that’s an option. What does this do? Well, it has weakened it by moving it more nasal. And now it’s also pulled it anteriorly. So it’s converting the inferior oblique to being somewhat of a depressor, perhaps, or at least a passive tether towards that eye drifting upward. And those are the two mechanisms that are thought to help control dissociated vertical deviation. We’ll go to the video here. And I’ll kind of talk about this, as we go. It’s edited, so it’s not too long. My standard approach to this is through a fornix incision. We see the patient has already had a medial rectus recession here. During the same procedure. We’re right above the fat pad area here in the fornix. Just 1 or 2 millimeters above that. Extending our incision towards the inferior rectus. Grasping the Tenon’s, cutting down through that, and opening up that pocket. Hook the lateral. And then this is that 4-0 silk that I like to place underneath the lateral rectus. It’s nice to use a tapered needle rather than a cutting needle, when you do that. And I do that so I can position the eye up and in, like this. I’m gonna pause it right here. I’ve taken that 4-0 silk that’s under the lateral, and I’ve put a 4×4 over the bridge of the nose, and I’ve directed the suture directly across that 4×4, and then I wrap it up towards the top of the head and clip it to the drapes on the forehead. The key move here is that when you pull that silk in, the cornea should rotate up and in from the suture. By getting the cornea up and in, that is bringing the inferior oblique down into this quadrant, more to where you can most easily hook it, near the insertion. And this helps you to avoid getting into a lot of fat and the vortex veins and other things that you don’t want to mess with. So this is a key move. You can also do this with a hook underneath the inferior and lateral rectus, but this is a nice way to do it, where the hemostat on the suture is holding the eye for you. Kind of frees you up to do this a little more on your own. And I’ll resume the video here. That’s a Von Graefe hook. A long, smooth hook going in. And I’m gonna scroll back just a touch, because it’s a nice demonstration right there. So that Von Graefe hook went in blind. It’s long. Longer than a Stevens hook. And you just go in, stay close to the sclera, and you scoop up — and you just get the entire inferior oblique on there, without even seeing it. I’ll scroll back a little bit more, so you can see that. This is the Von Graefe hook. Settle down. All right. So that’s a Stevens there. Here’s the Von Graefe there. It’s longer than a Stevens hook, but it doesn’t have a knob on it. And it’s just gonna go in there and blindly come up underneath the inferior oblique. Now, right here… Let me see if I can bring this back just a touch. There we go. Right here is the triangle we’re looking for. So to begin to orient you, this is the suture underneath the lateral rectus. This is just a Stevens hook, retracting the conjunctiva a little bit. The Von Graefe is off the screen here at the top, but it’s underneath the inferior oblique. This is the posterior border of the inferior oblique, going up over that hook, and then back down. This is the anterior border of the inferior oblique. We are looking at this white triangle, right here. Border of the inferior oblique. Sclera. And then right here is going to be a vortex vein. We’re gonna reach in that empty space and get right behind that inferior oblique. If you don’t see this, you need to reposition the eye. This is a critical aspect of this procedure right here. Not doing this leads to not getting all of the inferior oblique, or it leads to hitting the vortex vein. So you need this visualization. All right. Let’s resume the video now. There’s the Stevens hook, going in just past the border, towards the orbital rim. Bring all of that up. And then just take all the hooks out. Now we’re taking forceps to kind of strip it down, and we’re gonna buttonhole right past that, so that you can see we just pushed the forceps through. Now we have pretty much just muscle, by doing that. You don’t want all that fat out there. A couple Green hooks go in, in place of the Stevens hooks. Just a little better width to them, to hold things. And we’re gonna reverse this one and use it to retract and expose the insertion right here. Because we want to take down these ligaments right here, at the insertion. And then cross-clamp it with that hemostat. And I just cut down the back side of the hemostat. You don’t want to cut into the sclera here, because this gets close to the macula. So it’s okay to leave some of that stuff there. Now, we’ve isolated our section that we want to remove, if you were doing a myectomy. If you’re doing a recession or an anterior transposition, you simply suture right behind the hemostat. Some people will use a non-crushing hemostat, and kind of pull this muscle forward, and suture in front of it. What I do is suture behind it, and then a lot of times, I’ll leave the loops loose. And I’ll pull them forward at the end. Wasn’t done in this example, but you can pull the sutures up to the end. It’s always nice to look down in that quadrant, make sure there were no remnants of the inferior oblique left behind. Hook your inferior rectus, and now we’re doing an anterior transposition. So it’s gonna go right back next to the inferior rectus corner. So this is, in this case, about 1 millimeter in front of the temporal corner, which is right here. And you want to keep these two sutures close together. If you spread out this insertion too much, you tend to get increased chance of antielevation syndrome. And that’s when the inferior oblique is so spread out that it acts too much like a passive tether, and you get a little bit of restriction to elevation. So we just want to tie that right next to the corner of the inferior rectus. And you are in good shape. Now… If you had been doing a recession, you would have simply measured back 1, 2, 3, and over 1, 2, and you would have put it over here. Not much difference in these procedures. It’s really just orientation. Although if you’re recessing it, the orientation of the muscle should be straight across, following its path. In the anterior transposition, you’ve taken it, and you’ve made a J-shaped deformity, bringing it forward. So that’s the difference. All right. Now, this brings us to our question and answer section for the inferior oblique. I am going to open up the questions that we have here so far. The first question is: That I used to do inferior oblique myectomy, but now I do a tenectomy. I find it to be easier and quicker. What is your experience with this procedure and long-term results and outcome? So yes. So a myectomy, you’re taking out a piece of the muscle. A tenectomy, you’re just disinserting it. My concern with that is that they’re probably not comparable. That is going to be a weaker procedure. More akin to a mild recession. Because you disinsert that inferior oblique from its insertion, and if you don’t take a piece out, it’s pretty much gonna stick back to the sclera in that same quadrant. And it’s gonna be relatively anterior and close to the lateral rectus. So my personal preference is to take one more minute. It doesn’t take that much longer. Take one more minute and remove a piece of it. And I think that’s a relatively predictable, safe thing to do. Next question on inferior oblique is… Inferior oblique after cutting — you don’t use suture. You just leave it there, and it reattaches itself. That’s correct. And this disturbs some of the residents that I work with, when they first see us do this. And I ask them to open the hemostat and just let that muscle go. Because we’re always worried about lost muscles. That’s one of the most feared complications that we have in strabismus surgery. But this is much different than a medial rectus. That medial rectus retracts outside Tenon’s capsule, and you can just kind of wave goodbye to it, because it’s very tough to find it again. This inferior oblique just sits there. It doesn’t go anywhere. That’s why it’s kind of a self-adjusting process. It just re-adheres to the sclera, right there. And you’ll see this, when you reoperate on these cases. If you have persistent inferior oblique overaction, and you go back and look in that quadrant, it’s sitting right there. It’s adherent to it. So always good to explore those. And also, if you have persistent inferior oblique overaction after a surgery, look for strands that might be still at the original insertion, that were missed. We have another question about: What about braided recession of inferior oblique in cases of asymmetric inferior oblique overaction? So in this case, we’re talking about one eye has 1+ overaction, and the other eye has 3+ overaction. All right? To me, if these are — if the difference is one number between the two, one is a 1+ and one is a 2+, pretty much treat them the same. I either do recession on both sides or myectomy on both sides. When you get large asymmetry, 1+ on one side and 3+ on the other, there are times when I will do a recession on the lesser eye and a myectomy on the other. Next question is about anterior transposition in anticipation of a likely DVD. Well, that’s a good question. In fact, that’s how I was trained by my mentor during my residency. You’re operating for congenital esotropia, and the patient has some mild inferior oblique overaction already, but they don’t have dissociated vertical deviation. Do you just do the recession of the medial rectus muscles? Or do you go ahead and weaken the inferior oblique and prophylactically anteriorly transpose it? I think that’s okay to do. You know that if you have someone with congenital esotropia, there’s such a high incidence of having DVD develop — 90% — that it’s reasonable to go ahead and do that prophylactic anterior transposition. Yeah. I would have no problem with recommending that. What do you — next question is what do you do if you need to go back after a myectomy? Is it possible after you’ve done such a large part of it missing? You can go back to a myectomy. There have been times where I’ve gone back and tried to weaken it more. There have been other times you can convert a myectomy to an anterior transposition. Now, that might seem like it’s impossible, but you can find the insertion at the globe, and you can get a suture in it, and you can bring it forward. Now, I wouldn’t bring it all the way forward, like you normally do anterior to the muscle, but you might bring it forward and put it 2 millimeters behind the temporal corner of the inferior rectus. I think that’s quite reasonable. Here’s the next question, about bilateral anterior transposition. And this is a good point, I think. With anterior transposition of the inferior oblique, do you always do bilateral surgery? For me, the answer to that is about 99% yes. This tends to be something you want to do very symmetrically, and it really takes a lot for me to be talked into doing this asymmetrically. All right. I’m going to keep us moving forward into the superior oblique, because this is a nice large section, that has a couple great topics here. With superior oblique palsies. As well as Brown syndrome. As we get into this, this is our third poll question. And this is: What do you think is the most common cause of head tilts and vertical diplopia in adults? So poll 3. Coming up. Here’s a gentleman down here. In the corner. He has a head tilt. What do you most commonly think this is? Nystagmus? Is it thyroid ophthalmopathy? Inferior oblique palsies? Superior oblique palsies? Now, if you’re paying attention, of course, we’re moving on to superior oblique sections. So that seems like a pretty good option. And it’s true. Any time you see someone — especially an adult — walk in with a head tilt, and here’s the results of the poll — pretty much everyone was on board with this. Of course, these other things can cause head tilts. All of these can cause head tilts. But by far and large what’s the most common thing? Bet on the superior oblique every time. You can almost make these calls as you glance at the exam sheet and walk in the room. You walk in the room, and that patient’s got a head tilt, they have a 95% chance of having a superior oblique palsy. And these people complain of what we describe as diagonal or oblique diploma. They see two images like that. Any time they come up to you and say — I see two images up and down like this — you know, it’s going to be a superior oblique palsy, unless they have something like a skew deviation or some other relatively unusual deviation. Here’s a very classic example of your typical superior oblique palsy. We have this lady. She has a left head tilt. All right? Now, the three-step test, developed by Marshall Parks — this is just key to managing patients like this. People that have never had surgery before. They just come in with a first-time evaluation of a superior oblique palsy. They have a very characteristic pattern, and we call this SOS or same-opposite-same. Step one of the three-step test is identify which eye has the hypertropia. She has a right hypertropia. And remember, we’re always talking about the hyper. The eye that’s up. You wanna keep this clear by using that reference. She has a right hypertropia, 15 prism diopters. So that’s step one. The hypertropia is on the same side as what we anticipate this palsy to be. It increases on gaze to the opposite direction. So she has a right hyper. We see that it’s worse in left gaze. So opposite. And then the third part of this is same. Her right hyper, which is worse on opposite gaze, is also worse on head tilt to the same side. So same-opposite-same. When I evaluate these patients, I will sit there and I’ll draw these grids out, and I’ll look for this pattern. The mechanics of the three-step test is enough involved that we’ll save that for another lecture in the complete evaluation of superior oblique palsy, but this is something that all of us should be able to recognize. The other thing that I really want to emphasize is the role of torsion measurement, when you’re operating for superior oblique palsy. It really makes a difference in what you end up doing. And one of the things I notice as I travel around the world is that most clinics don’t have these available to them. The double Maddox rod, where you have a red lens and a white lens, these lines going up and down — over here you see they actually produce a horizontal line. And if you have no torsion, those two lines are parallel, like this. But if you have torsion present, one of the lines is slanted or tilted. You allow the patient to dial that up until they become parallel. And then you can simply look at the lens holder and measure the degrees of torsion. And in this case, it’s excyclotorsion. Excyclotorsion is what we expect with superior oblique palsies, because it is an in-towarder. There are some basic pearls to this. And they affect what surgery you do and what evaluation you do. Congenital palsies, which by far are the most common thing that we see, usually have little or no excyclotorsion. I would say a typical patient that I see with a congenital superior oblique palsy in one eye has about 2 to 3 degrees of excyclotorsion. Acquired palsies always have torsion. And it’s usually a relatively significant amount. 5 to 10 degrees, range. Bilateral palsies. This is a big one, because they can be asymmetric. And one side can be masked, and it only looks like a unilateral palsy. These patients are the ones that have complaints of torsion. Doorways look slanted. These people have more than 10 degrees of torsion on double Maddox rod. The reason all of this is important — if it’s a congenital palsy, you’re probably not gonna work that patient up. If it’s an acquired palsy, you probably want to know why they have a superior oblique palsy. Okay? So this and vertical fusional amplitudes. So you probably want to do some neuroimaging, or at least some more investigation. Bilateral palsy — the surgical treatment for that is vastly different than the treatment for a unilateral superior oblique palsy. So it really does guide your treatment, and you should make every effort to try to measure torsion on these patients. Well, once you’ve done your evaluation, now we have to operate. What do we do? What surgery do we do? Well, Phil Knapp and his classification has been all built around the concept of matching your surgery to the field of greatest deviation. All right? And we see this with restrictive strabismus too. So find out where the deviation is greatest. Identify the muscles that work in that area. And work on those. That’s pretty much the concept of most strabismus. But it becomes a little more complex with superior oblique palsy. How do you magnify that? Well, that gets adjusted based on — what’s the degree of the deviation in the primary position? What’s the magnitude? Is the superior oblique tendon lax or not? Is the superior rectus contracted, because the eye has been hypertropic for so long? So let’s touch on these, before we get into the surgery itself. If the vertical deviation from the superior oblique palsy is less than 15 prism diopters in the primary position, you usually can get away with one-muscle surgery. And for me, the go-to on that is I weaken the antagonist inferior oblique on that eye. So if I have a right superior oblique palsy, I’m gonna do a right inferior oblique myectomy. And that’s gonna give me up to about 15 prism diopters of vertical correction. You can do recession. I might do that. Sometimes you see these unilateral palsies, and they’re pretty well controlled, but they have diplopia, and they might only have 5 degrees of vertical, or 5 prism diopters of vertical, and I’ll kind of chicken out and do a recession of inferior oblique in those cases. It’s rare that that’s not my go-to surgery, as the first muscle for superior oblique palsy. And there are other options, which we’ll discuss when we get into two-muscle surgery. You always want to evaluate for the possibility of a contracted superior rectus. But usually these are large deviations. Same with recessing the contralateral inferior rectus. Those are large deviations. And you’re usually doing inferior oblique plus one of these. That takes us to our next slide. If the deviation is more than 15 prism diopters, just doing the one muscle, the inferior oblique, is not gonna be enough for most of these patients. So this is when we want to do inferior oblique plus one or two other muscles, depending on the magnitude. The most common second muscle that I do for a superior oblique palsy is go to the opposite eye and recess the contralateral inferior rectus. Let’s think about this. We have — I’m gonna just back up, so that we can look at our patient, while we talk about this. Now, why are we going to the other eye? Well, let’s look right here. This lady has a right superior oblique palsy. Right? So the right superior oblique normally would take the right eye down in the adducted position. It would take it down here. But it’s weak, so the inferior oblique is winning, and it’s pushing the eye up. So right here — the yoke muscle to this is going to be the inferior rectus over here. So the superior oblique on this side takes the eye down and to the left. The inferior rectus on the other eye takes the eye down and to the left. So her deviation is greatest over here in left gaze, so we need two left gaze acting muscles. Superior oblique. Inferior rectus. You weaken those two, and this gives you about 15, and then you can get another 15 or so over here. When you weaken, recess an inferior rectus, as we talked about in the last webinar, you expect in a normal eye to get about 3 prism diopters of correction per millimeter of recession. So if I have a person with 30 prism diopters of vertical deviation from the superior oblique palsy, I’ll do the inferior oblique. That’ll give me 15. Then I’ll do the inferior rectus. 5 millimeters on the other side. And that’ll give me another 15. So up to about 30 prism diopters. Alternatively, if you do traction testing and the superior oblique is lax, loose, you may want to tuck that. We’ll talk about that. And you always want to see if the ipsilateral superior rectus is contracted. If a person has been walking around with a right hypertropia in their eye up here for a long time, that superior rectus may have stiffened and contracted. Just like the medial rectus will with a 6th nerve palsy. And these people, because it’s the superior rectus that’s stiff and tight, their area of greatest deviation will be down on that same side. So down and to the right in this case. That’s where, looking at the deviation, pattern deviation, up and to the right, up and to the left, down and to the right, down and to the left, that’s where these kind of oblique areas become important for strabismus evaluation. Most of the patients we see — you just need primary and maybe up and down. Maybe left and right. But in these cases, you want to look at those oblique positions. Grading the laxity is another one of those subjective things, like DVD and inferior oblique overaction. It is subjective. And some people don’t like that. But you just have to do it a lot and get used to it. When you do this, you’re doing it under anesthesia. Don’t do this in the office on an awake patient. This is under anesthesia. You’re grabbing the eye obliquely. You’re pushing it back into the orbit. And then you’re gonna roll it around, up and over that superior oblique tendon. And we’ll show you a video of that. And then you estimate its laxity. -4 means you don’t feel anything at all. You don’t even know if there’s a tendon there. All right? So let’s keep going here. This is how you grasp the eye obliquely. This is the left eye. So the surgeon is sitting right here. Left eye. Right eye. So you can see how we’re grasping it obliquely. Grasping it obliquely, just because you’re gonna push it up and in, up and in, and you want your forceps out of the way. So then you rotate the eye up and in. Cornea starts to disappear up under the eyelids. And you can just push it in like that. And you can see that the cornea doesn’t quite bury here. Whereas, on the right eye, the cornea totally disappears. So you get some immediate sense that the right side is loose, compared to the left. And if you then roll the eye back and forth, you can actually feel that tendon and feel that laxity. And that’s the video we’ll look at here shortly. Patient like this previous one — normal tendon, left. Lax tendon on the right. What do you find when you get into surgery? Find something like this. Here’s the right superior rectus. Here’s the right superior oblique on a Stevens hook. Normal. Sorry, left. Here’s the right superior oblique on a Stevens hook. And you see how it’s lax and it’s redundant. Okay? Up and over. So there’s a lot of give there, compared to the other side. Well, if you have one like that, a lot of times it’s helpful to tuck it or strengthen that tendon. It’s difficult to resect a superior oblique. So that’s one reason why we don’t typically do that. It’s all tendon. So it’s tough to cut that tendon out and get it to heal in place, necessarily. So a lot of times it’s just easier to tuck it on the temporal side. So here, this is actually a tendon tucker. But I do this just with a muscle hook underneath the superior oblique. Lift it up like this. And place a couple Mersilene sutures through the borders. And so you have this redundant area, which might be 4, 6, 8 millimeters. And then you can lay it down and then tuck it, or I just leave it up like this, and it lays down on its own. I like to use this Mersilene suture, braided polyester. Once you do that, the endpoint of that is repeating the traction testing, so that it feels symmetric. You want both eyes to feel the same. If it doesn’t feel symmetric, then you’re gonna induce a Brown syndrome. You want to take that down. So always err on the side of undercorrection. People have — with superior oblique palsies — tend to have large vertical fusional amplitudes, but they’re one way. You overcorrect them, they’re not very good at going back the other way, and they get a reverse diplopia, which is pretty annoying to them. All right. So the next section is Brown syndrome. But before we do that, let’s talk a little bit about superior oblique palsy. I’ll bring up the questions here. And you can see — this is just a lot of material. And we don’t want to rush through this, because we want to get to our questions. And come up, questions. There we go. All right. Here we go. And… Getting down to superior oblique questions. All right. Here’s a question about tuck. Talk about superior oblique tuck — does it hurt more to do a tuck than a recession? I don’t know that… You know, when you do recessions and resections of rectus muscles, people definitely have more pain when you resect or tuck a rectus muscle. But I don’t think that’s necessarily the case with the superior oblique. You don’t tend to recess the superior oblique in general. You just do a tenotomy. I suspect that doesn’t hurt much at all. There probably is some tension. It’s the tension on the muscle, any time you strengthen it, that causes that cramping feeling for people. So there probably is some discomfort. How to deal with torsion? When to plan for Harada-Ito? Good question. We have that in here. I’m just gonna bounce on ahead on to that, because that’s a great topic, is the Harada-Ito. Let’s roll through Brown syndrome here for a second, before we get to the Harada-Ito, though. Brown syndrome. You have a tight tendon. So it’s kind of the opposite of superior oblique palsy. The tendon is tight. And here this child’s got a right superior oblique palsy. He’s looking to the left. His right eye won’t go up. But when he looks to the right, it goes up pretty much normally. Sometimes there’s a little bit of restriction. And this is usually just a tight tendon or an anomaly of the trochlear complex. Another patient — this lady looks good in the primary position, for the most part. Maybe a little hypo, here. Great in right gaze. But left gaze — she gets this big right hypotropia. She gets a right superior oblique overaction. So these down-shoots. Pretty much the hallmarks of Brown syndrome. Now, sometimes you’ll get anomalous head turns with this. This young lady has a Brown syndrome on the left eye. So she doesn’t like looking to her right. Because the left eye gets hypotropic over there. So she turns her face away, so that the superior oblique is not really doing any work here. She’s mostly positioning the eye vertically with the superior rectus and inferior rectus. So she’s taking the superior oblique out of the picture with this face turn. So when to operate? Anomalous head postures, hypotropias, diplopia. Those are all reasonable reasons. Some people, they have a Brown syndrome and are asymptomatic. You don’t need to operate on them. Just like if you have inferior oblique overaction and it’s asymptomatic. Treatment is superior oblique loosening. Right? You can either do a tenotomy, free tenotomy, or a guarded tenotomy. Let’s look at that. So superior oblique free tenotomy — you’re cutting completely across the superior oblique tendon. Just gonna chop it in half. We usually do this right along the superior rectus border. If you cut closer to the trochlea, you will get more weakening, and it’s also a bit more unpredictable. So we tend to avoid that. Usually we’re working right out here, by the superior rectus, where the oblique travels underneath it. This one I’m using step by step photos to demonstrate, because there are some little key points that we’ll stop and point out. So I’m just gonna kind of go through a series of photos here. Step by step, how to do a superior oblique tenotomy. That also will show you how to do a spacer. So I like to measure back. There’s so much sclera, conjunctiva, exposed up here in the superotemporal quadrant, where we’re working. This is superotemporal, on the left eye. There’s so much room up here. You don’t want the fornix incision way back here. So I tend to measure back about 8 millimeters, and just run it out right there. So that’s what the caliper is here. Extend your incision, kind of following the lid contour a little bit there. So you see, we’re not down here. We’re right out there. Extend that. Same as you do other strabismus surgery in the fornix. Lift up your Tenon’s, cut down on that, and then you’re going to hook the superior rectus. A couple key points here. Keep in mind the superior rectus is the muscle that sits furthest back from the limbus. Getting back in the 7-millimeter ballpark here. So some people have a tendency to miss it. They go in front of it or they go back too far. You don’t want to go back too far, because back in here is also a vortex vein. So you want to be right in the sweet spot here. Just a little bit past the insertion. Replace that with a couple larger hooks, knobbed hooks, Jameson hooks, square hooks, Green hooks, whatever you like. Once you do that, we reflect the conjunctiva back over, but we’re not going to buttonhole here at the muscle hook tip, like we normally do. We’re gonna leave this intact. And I’ll explain to you why that is. But we’re going to retract the conjunctiva back, place a Desmarres retractor in there, and then now, still with the septum intact here, we’re looking for this transverse condensation of muscle tendon sheath. And we’re gonna pick that up off the surface of the superior rectus and just make a buttonhole in it right here. Once we’ve done that, we put two Stevens hooks in, and we’re kind of stretching open that buttonhole a little bit. There’s the surface of the superior rectus, right there. Everything else is still covered in sheath. That Desmarres comes back in and goes into that buttonhole, to make that buttonhole larger. So we’re looking at the surface of the superior rectus. The reason for that is: Now we’re over here. Our incision was out here, temporal. Now we’re looking here, nasal, along the superior rectus. This, about 8 millimeters or so back, is where the superior oblique exits from underneath the superior rectus. And it becomes — it’s very fanned out here at the insertion. But right here, it condenses down to this pearly white 3-millimeter-wide band. It’s the easiest place to identify and make sure you hook the entire thing. So that’s why we’re using this Desmarres and going to the nasal side. This is also where we’re gonna cut it. So it’s where we wanna be. Once we’ve identified it like that, we’re just taking a Stevens hook and going from behind, coming up underneath the width of that pearly tendon. Put another Stevens hook in, and you can kind of identify it. So we’ve left all this tendon sheath nasally intact here, and the reason for that is: If you want to do a spacer, you like to leave the bottom side of this tendon sheath intact. We’re gonna open up the top side right here. And this is all the same, whether you’re doing a free tenotomy or a guarded tenotomy. I just picked it up and spread it with the scissors. Now we see the absolute pearly surface of the tendon. So the sheath is still intact on the bottom. But we’ve exposed the tendon on the top. Now, if you want to do a free tenotomy, right here along the nasal border of the superior rectus, just take your scissors. Cut all the way through that. And you’re done. Boom. Cut. Here it is. It retracts a little bit. That’s a free tenotomy. Now… If you wanted to put in a spacer — this was proposed by Ken Wright is a way to avoid overlengthening of the superior oblique once you cut it. This involves not — before you make this cut across the tendon, you pre-place a couple prolene sutures on either side of where the cut is going to be. And this is usually a 6-0 prolene. The particular needle is a C1 that I use. Once you pre-place those sutures, then you take a section of a retinal band. This is a 240 retinal band, and you’re gonna use anywhere from 4 to 8 millimeters of that. And you’re going to place the suture. The pre-placed suture that’s in the tendon. Pass it through the ends. And then you’re gonna suture that in between the cut ends of that tendon. So now you have tendon, retinal band, more tendon. You’re just making it longer. So it’s a controlled lengthening. Now, we talked about traction testing. Here is a pre-op traction test on a Brown’s patient. Look how tight that is. You can’t move that cornea up there at all. Here’s a postop. We’re gonna see the tenotomy. And these are opposite eyes, by the way. We’re gonna see the tenotomy. Right there. Cut the tendon. Snaps free. And we’re gonna reposition everything and we’re gonna repeat that traction test now. Rolls way up there. So you can see a big difference. All right. Looks like I don’t have the Harada-Ito slide in here. So let’s — we can talk about that. But let’s go to questions from the superior oblique. Yes. So… Here’s one of my favorite people. Dr. Murray, in South Africa. Has asked us to comment on the management of bilateral superior oblique palsy. Specifically the fact that these patients have torsion. V patterns. And verticals in the primary position. And he’s right. These are different animals in how they’re treated. And I think, because I don’t have that slide loaded, I’m gonna save that. That’s gonna be our opening for the next webinar. I’m gonna start off — finish, rather — with superior oblique palsies. Because I want to demonstrate the Harada-Ito as it is involved with these bilateral palsies. So I’ll defer that one. It’s a great question, though. And I love you, Dr. Murray. You’re a good guy. Here’s another question. Do you use any traction test to decide to operate on a superior rectus, or are the measurements your guide to that? So the decision to operate on the superior rectus in the case of a longstanding superior oblique palsy with superior rectus contracture… You know to look for it based on the measurement. So down and out on the side of the hypertropia. So if you have a right superior oblique palsy and the right superior rectus is contracted, their maximum deviation is going to be down and to the right. So if you see a large deviation down there, you suspect that the superior rectus is contracted. You confirm that during your surgery by doing a traction test, or in the office, of the superior rectus. And if those two things are consistent, that’s when I would recess the contracted superior rectus. Another question. In the last case you presented, did you suture the muscle in the end? So if you do a free tenotomy — I think that’s what they’re referring to — if you do a free tenotomy, no. You just cut across that tendon and you let her go. It doesn’t go anywhere. It just kind of reattaches to the globe. It has all kinds of attachments between the superior oblique sheath and its overlying superior rectus. If you take the superior rectus off, when you’re doing your recession, look at the underside. You’ll see how the superior oblique is adherent to it. They share a common sheath. So it retracts, but then it just kind of hangs out and scars into place. So it’s — again, it’s like a myectomy. You get a controlled lengthening or semi-controlled lengthening, and then it heals in place. Another question. My good friend Dr. Kav. How do you handle a patient who has both a superior oblique palsy and a true hypertropia? Well, I guess, to me, I maybe don’t make a differentiation between these. If they have a hypertropia, I want to attribute that to something. They may have a superior oblique palsy that’s causing a true hypertropia, and it’s just manifest. So I think there are different degrees of control when we talk about superior oblique palsies. It reminds me of another thing. We call these superior oblique palsies or 4th nerve palsies, but I think the vast majority of these cases — it’s not a nerve palsy. All right? It’s not like a 6th nerve palsy or a 3rd nerve palsy. A lot of these, especially on the congenital ones, it’s just a tendon that’s too long. Just like a Brown syndrome is a tendon that’s too short. Now, the acquired cases are different. Right? You get a head trauma, someone’s brain gets sloshed around back and forth, that 4th nerve does get stretched, then. And that’s why they present differently. Right? You have more torsion in these acquired palsies. They just behave a little differently. So it’s 50/50. It’s kind of a generic term. Maybe not the best term to talk about being a palsy. Because a lot of these are just tendons that are too long. I’ll finish with this last one. And that is how do you manage a traumatized vortex vein? Well, I can tell you that. I’ve done it before. I can distinctly remember a case when I was the first-year faculty member and was operating with a fellow, and we managed to hit a vortex vein — two on one eye. It’s tough, because the bleeding is very posterior. It’s like there’s a cone going back into the orbit. And the vortex vein breaks off where it enters the sclera, and so it’s like a well being filled from below. That blood’s just coming forward. So you end up with blood that’s coming up and filling this cone, and so you can’t see. It’s just like… Clampett’s geyser here. The best thing to do, since you can’t see, is to cauterize down in the bottom. Just put pressure on it. I take a few cotton tips, and I’ll just push them back there and sit tight. You could put phenylephrine on those cotton tips, but I would just use pressure. If you hold pressure back there with the cotton tips for a little bit, that vortex bleeding will settle down. Once it settles down, you can pull the cotton tips out, look in there, see if you need more pressure or not. But once it settles down and you have some idea of where the vein, then you can get a cautery instrument back there and maybe top it off a little bit. It doesn’t really hurt anything. It just makes for a really messy surgery, and you’re not too happy that you did it. So we are out of time with this webinar. And just as I was quite certain would happen, we have a lot of material left. So when we come back with the next scheduled portion of this, we’ll pick up with bilateral superior oblique palsy. It’s really an important topic. And we’ll talk about the torsion control, Harada-Ito, and how a lot of times the surgery is completely different for a bilateral palsy. We generally don’t weaken inferior obliques. We’re typically doing things like recessing inferior rectus muscles, and we’ll discuss that. And then we’ll go on to some of the more unusual restrictive strabismus syndromes, like Duane syndrome, fibrosis syndrome, thyroid myopathy, as well as talk about Botox and adjustable sutures. So we have a lot to look forward to. Thank you for your time. I will go through the questions that we didn’t get to today. And I will write answers to those, and we’ll distribute those to everyone, and then we’ll pick up where we left off. Thank you. Again, just a last reminder — go to Cybersight.org. Look at all the free material that’s there. Complete textbooks are available there, as well as videos of these procedures. And please use the consult function, if you have a problem that you need some guidance on. Even general questions. Please write us. We’re here to help you. Thank you and have a good day.
April 21, 2016