This lecture will review the appropriate preoperative assessment of Superior Oblique cyclo-vertical muscle disorders including unilateral and bilateral 4th Nerve palsied and Brown Syndrome. Surgical videos will be used for demonstration of appropriate technique.
By Dr. Daniel Neely
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DR NEELY: Well… Welcome to the next of the webinar series, the Orbis Cybersight webinar series. Today we’re joining about 70 different countries around the world. The topic for today’s presentation — we’re going to discuss the management, evaluation and management of superior oblique palsies. Particularly as a discussion. We want to hear from you. Want to hear your questions. And during the course of this, we’ll go through a chat. And… So we’ll go through a chat. I’ll be receiving your questions during the conversation, and we do want this to be a conversation. If a question comes up at a time in the presentation that’s appropriate to answer then, I’ll take care of it then. Otherwise, we’ll take care of that — kind of save those up, and take those at the end. Let me go on and open up our first screen, here. Sorry about the rough start there. I was a little unsure if you could see me or not. It looks like we’re in good shape. All right. So, again, this is the evaluation and management of the superior oblique. The superior oblique is — it’s interesting, because it’s probably the most complicated and intimidating muscle, particularly for novice strabismus surgeons. So I think it deserves some special attention. Before we get started, I’d like some feedback from you, because I do want this to be interactive. So the first poll question here is I would like to know who you are. You may be in a mixed group, but you may be an individual. Are you an ophthalmologist, ophthalmologist in training, registrar, nurse, ophthalmic technician, medical student? What is your position? All right. So here are the results. Most of us are ophthalmologists. We do have some ophthalmologists in training, a few nurses, ophthalmic technicians, medical students. And most of this obviously is going to be directed towards clinicians. We won’t spend a lot of time going over superior oblique anatomy and function, but I think it is worth spending about two seconds to look at this, because it’s this unique pulling structure of the superior oblique, and its insertional position, which is behind the equator, and temporal to the optical axis, which accounts for its actions. So the primary function of this is in torsion. But keep in mind that the secondary function of the superior oblique is depression. And that’s why when we see superior oblique overaction, it’s pushing the eye down. Now, the third thing, abduction, because of this insertion back here, in that posterior temporal quadrant, that is pulling the back end of the eye in, and that’s what accounts for the abduction, with the superior oblique. Superior oblique overaction — most commonly, superior oblique overaction is going to produce A-pattern strabismus. When we’re wanting to do anything surgically, it’s usually because of this, or because of a cyclovertical deviation. A-pattern? What do we mean by A-pattern? Well, A-pattern means the measurements between the downgaze position here and the upgaze position here are more than 10 prism diopters. It’s normal to have some, but more than 10 is significant. So let’s look at an example. These are the nine diagnostic positions of gaze. We’re mostly gonna concentrate on the center column as we look to A-pattern. But there’s a mild amount of left superior oblique overaction. Maybe not quite so much here, but a little mild superior oblique overaction on the left side as well. Here’s an illustration of why it’s A-pattern. Look at the downgaze. The eyes are straight or slightly divergent. They’re more ET in the down gaze and much more in the upgaze. So this is why we call it A-pattern. How do you diagram that? We need to know how to convey this in our charts and share this information with other people. And there are a couple of different formats. I have them both on here. Typically this would be the right eye on this side and then the left eye on this side, as you look at the paper. And you can see it corresponds to those positions of gaze, kind of the primary function of each of the muscles. This asterisk-shaped one is probably the most commonly utilized, and you’ll see this is the one we use on the Cybersight consult website. If you’re going to indicate overaction, I’ll usually put a +2. But you grade this somewhat subjectively, anywhere from +1 to 3 or 4. Another one that you’ll see sometimes is this kind of H-pattern. But same thing. The nose is here in the middle. This is down and to the left, and this is down and to the right. Another way to document that overaction. This is a very nice Cybersight case. Consult that came in from Dr. Kruse, and I selected this because it highlights nicely an A-pattern case. I’ll blow these up so we can get a nice look at them. In here, when you bring up the measurement grid, in the nine diagnostic positions, you can see… Those are the same numbers. We’ve got 5ET in downgaze, 30 in primary, and 60 in upgaze. So we have an A-pattern. Since that’s such a large difference between up and downgaze. Similarly with the photo montage, this is laid out in the same way. And you can blow these up, using the preview buttons to look at these. And again, we’re gonna concentrate on what this looks like in the up and down column and then down and to the sides. The downgaze — that child looks pretty straight. Maybe just a little ET. Primary position, significantly more esotropia is visible here, and you can see upgaze, he has quite a bit more. And this is where we’re measuring 60 in upgaze. Superior oblique action is a little bit more visible. You can see that this left eye when it’s down and in is overdepressing a little bit, and likewise, you really see it here with his right eye, where he’s overdepressing in a down and in position. So again, the way to document this in the Cybersight format is you have that asterisk in the background, right eye is here, left eye is over here, and simply click on the arrow, and you can bring the grades up and down, anywhere from a +1 to a +4, or a -1 to a -4, depending on what you need to document. This brings us to our next poll question. Probably the easiest way to deal with A-patterns are shifting the horizontal recti. So you have an A-pattern esotropia, and you want to collapse that, you can shift the medial rectus, to help compensate for that. So when vertically shifting the horizontal recti for an A-pattern, which way do you shift the muscles? We’ll talk about how to remember this. So for A-pattern medial rectus or horizontal recti, if we’re working on the medial recti, are we shifting them up? If we’re working on the lateral recti, are we shifting them down? Or are both answers, 1 and 2, correct? Or are both answers, 1 and 2, incorrect? Okay? And sharing the results of these… We have a bit of diversity here. And let’s look at this. The majority of you answered both answers, 1 and 2 correct. Medial recti are shifted up, and the lateral recti are shifted down, for the A-pattern. How do we know that, though? How do we know what to do? In general, you don’t necessarily have to understand the mechanics of this, but you need to make sure that you’re doing the right thing for a given pattern. There’s the frequently cited mnemonic, MALE, which stands for medials to the apex. When we say apex, we mean the top of the triangle right here, and laterals to the empty space. So we’re talking about putting the laterals out here, towards the empty space of the pattern. So here we have, starting over here, this is a V pattern strabismus. So if you’re doing something to the medials, whether it’s a recession or resection, you’re gonna shift them towards the apex. Medials to the apex. And likewise, if you’re doing something to the laterals, in this V pattern patient, it doesn’t matter if it’s esotropia or exotropia, you’re shifting the laterals towards the empty space of the pattern. The laterals are gonna go up. Same parameters here on A-patterns. Medials go to the apex of the pattern. Laterals go to the empty space of the pattern. So that’s how we keep this straight, with this mnemonic, MALE. Now, the beauty of horizontal rectus muscle shifts up and down is that it’s simple. It’s frequently — a couple muscles that we’re already operating on anyway. And most even novice strabismus surgeons can shift these up and down. How much do we shift? It’s variable. Anywhere from a half to a full tendon width. When I do it, it’s about half a tendon width. When you get into a full tendon width, that’s full tendon transfer. But about half is what I typically do. This is good for small amounts of A and D-pattern. Particularly when you don’t have any significant oblique muscle dysfunction. When you start to get significant oblique muscle dysfunction, of the inferior or superior oblique, you need to operate to get those patterns collapsed. And here’s an example, again, illustration — this is an A-pattern esotropia. You can see the medial recti being resected. And the medials have been shifted upward. This is an extensive shift. It’s pretty much one full tendon width. So that’s what it can look like. Do you have to combine this with recession or resection? No. If you have someone who’s aligned and you just want to collapse the pattern, you can simply follow the spiral of Tillaux and shift those muscles up and down. As I mentioned, if you do have some significant oblique muscle dysfunction, you really want to do something to that muscle. Since we’re talking about superior oblique and A-patterns, we’re going back to the same patient that we demonstrated from South Africa, 60ET in upgaze, 30 in primary, and 5 in downgaze. Here you see the documented overaction. Got +3 on a superior oblique grading. Both eyes. So before we go into surgical techniques, we’ll probably talk about Brown syndrome. Because both Brown syndrome and this treatment of A and V-patterns may involve superior oblique tenotomy. First I’ll see if we have any questions in the queue. The first question I see is from Dr. Tandeli. He had a surgery in an A-pattern patient with Brown syndrome. Total tenectomy was performed, and a large hypotropia persisted. So then recession of the inferior rectus was performed. So you’re dealing with the residual deviation after tenotomy or total tenectomy. Let’s see how that can be addressed. And I’ll go back to our screen share here. Right. So related to this question, Brown syndrome. Brown syndrome can be a very interesting condition. As you can see from this question, sometimes it can be a very difficult thing to treat. Brown syndrome — the hallmark of that — here we have a patient with right Brown syndrome. The hallmark is that with the eye in the adducted position, it does not elevate well. Not only may it not elevate well — sometimes it will actually be depressed. So here, in this first photograph, we have a patient trying to look up and to the left. And you can see the left eye is going up just fine. The right eye… Pretty much no elevation. Conversely, on the other side, when he’s looking up and to the right, both eyes are elevating essentially normally. And that’s one of the things to point out. Here the right eye in the adducted position is not going up. This one looks pretty normal, but frequently in the abducted position, you’ll see some limitation to elevation there as well. Sometimes that gets a little bit confusing. Can be consistent of mild elevation deficiency. But in general the elevation should be better in the abducted position. Really severe cases, when that tendon is much too short, or tight for other reasons, you can see they actually develop a hypotropia. Here this young lady has primary position… Not too bad. When she goes to her right, things look pretty normal, but when she tries to go into left gaze, she’s getting a downshoot, because this right superior oblique tendon is so tight. Well, indications for surgery… Just because someone has a Brown syndrome doesn’t mean that you have to operate on it. A lot of times, these will just kind of get better, as the child gets older. Another thing — when children are small, and they have a Brown syndrome, when they’re short, the Brown syndrome is more evident, because they’re looking up towards the adults. But as people grow, not only are they looking up less, but in general, a lot of times these tight tendons seem to improve on their own. So not everyone automatically needs surgery, just because they need a Brown syndrome. Who do we operate on? If you get a hypotropia in the primary position and they can’t get up to the horizon, that person needs surgery. If they have a large face turn like this one — this young lady has a left Brown syndrome. She doesn’t like that eye to be in the adducted position at all. So she’s got a face posture as a result of that. That would be another reason for surgery. Diplopia, double vision, of course, and sometimes we’re doing these for cosmetic reasons as well. So observation… Always a reasonable choice. If we’re going to treat these, we need to do something that’s going to loosen that superior oblique tendon. The superior oblique is generally tight, so we need some way to relax that. A couple ways to do that — free tenotomy, as was done by the person asking the question. Another way to do this is with a guarded tenotomy. It’s basically a way to control so that you don’t get an overresponse, and create a superior oblique palsy. So in this question that came up earlier, there appeared to be not a sufficient resolution after a full superior oblique tenotomy. Well, there are ways that the tenotomy can be more powerful. How is that? This question is: when performing a superior oblique tenotomy, cutting the tendon closer to the trochlea produces no weakening, minimal weakening, or maximal weakening? So by changing where we cut the superior oblique, we can control the effect that we get. And I’m gonna go ahead and show the results of the poll. So cutting — most of you went with maximal weakening. And that’s exactly right. That’s the point of this. Going on to the next slide here, when we do a superior oblique tenotomy, here’s the superior oblique and the scissors between two hooks — this is not just a random position that we’re just cutting anywhere we want. We normally are cutting right along this nasal border of the superior rectus tendon. But if you have a tenotomy that didn’t work, it’s probably a good idea to maybe go back and reexplore this, because a couple things can be the case. One, maybe you just need to cut it closer to the trochlea. But the other thing is… I think a lot of times when people are isolating the superior oblique, they split it and maybe don’t get all of it. And so one of the things that we’re gonna touch on next is going through the steps of how to do a really appropriate superior oblique tenotomy. This is all about setup. It’s all about exposure. And I think if you follow these steps, you’ll find the results of your tenotomies are more effective. So cutting closer to the trochlea gives more weakening. Cutting closer to the superior rectus gives less. And if you really need a tiny bit, you can just do a disc insertion here from the temporal side. So several options. Here we have a Brown syndrome traction test. Now, the traction test is one way we can help quantify these tight tendons. So I’m gonna scroll over and go to… A video here. And let’s look at this traction test. So here’s your Brown syndrome. You can see how tight that is. We can barely… See it kind of riding up and over the tendon. It’s even hard to push the eye up and in. I’ll bring it back. Even just pushing the eye up and in — it doesn’t really wanna go. So this is a really tight tendon. And keep this in mind, because we’re gonna come back and look at this after tenotomy has been done. Close this out. You can hear that video still running. I’m gonna go back and stop that. There we go. All right. So that’s our traction test. What we’re going to talk about is how to do a really good superior oblique tenotomy, kind of in a step by step fashion. This technique was taught to me by my senior partner, David Plager, and this is the surgery that he has done, that will be demonstrated here. And these pictures were taken by another Orbis user and faculty now. So when you’re doing a superior oblique tenotomy, we need to get back where the superior oblique is. Here we put the locking forceps right at the corner of the superior rectus. The superior rectus is right here, and you can see a couple of the anterior ciliary vessels coming off the superior rectus here. So this is how we know where it is, and we can kind of keep track of it. I’ll generally measure back about 8 millimeters. And the reason I measure back before I make the conjunctival incision is there’s a lot of fornix here. This wide expanse of the sclera… When you come in here, measure back about 8 millimeters… All right? So once we’ve measured back, we create our conjunctival incision. About 10 millimeters in length. And then we’re gonna go through Tenon’s, lifting this fold. Once we go through these photographs, I’ll play the video for you, so you can see this in edited, somewhat, realtime. Cutting down on Tenon’s in the opposite direction now. So far, this has been all pretty standard fornix incisions. This is the left eye. We’re approaching this from a superotemporal position. And the reason for going temporal is that this preserves the tendon on the nasal side. So that you have options for doing things like guard tenotomies, guarded tenotomies. It’s also a bit easier to find on the nasal side. But we like to keep that area relatively clean. There’s also a tendency to perhaps accidentally hook this superior oblique tendon when you come from the nasal side, and here on the temporal side, the insertion is further back, so there’s more room to work in here. So this is from a superotemporal approach, and when you’re placing the hook in, the superior rectus is gonna be about here, 7 or 8 millimeters back. You don’t want to go too far back. You need to go further back than normal, than the other rectus muscles. But don’t get too far back in here. If you go too far, you’re gonna find the superior oblique. You don’t want that. I’m gonna hook the rectus a couple times, make sure we have the entire width of it, and expose the surface of the superior rectus. You’ll notice on the nasal side of the superior rectus, we haven’t opened up the Tenon’s and the muscle capsule, on purpose. Normally we’ll make a buttonhole, but here we’re leaving that filmy layer intact. The reason is we don’t want to create any scarring out in this area. Here there’s kind of a condensation of the muscle capsule, and that’s what we’re gonna grab and incise. Once that’s incised, you can open up and see the surface of the superior rectus, and expose that. And again, we’re leaving the nasal border untouched. We move the retractor into the opening that we’ve created, and now we can kind of get back here. Again, this is gonna be about another 7 to 8 millimeters back from the superior rectus insertion, and you can see now we can see the tendon. So it’s pretty far back. Some people will even increase their exposure, by taking the lid speculum out. But we’re looking for this pearly white condensation. And the steps that are leading up to this view right now are pretty much — those are the critical steps. What you do with the tendon? Whether you cut it, or you’re doing a guarded tenotomy — that’s the easy part. Having nice exposure, so that you know you have all the tendon. This is really what makes or breaks the superior oblique procedure. I like to hook it from the back side. I think that helps me ensure that I have the entire width of the tendon. And then you can put a second Stevens hook in there and spread it out. It’s inside the capsule here, and we can see pearly fibers, but there’s still this layer of capsule. Then we can open that up with the Westcott scissors, and then now you have the bare tendon to work with. Backing up… There’s just been a small buttonhole made in the top of this tendon. So if you were gonna do something like a guarded tenotomy, you have a nice sleeve to put that back into, and we’ll look at that next. All right, so there’s our tendon, and then we cut that. Cut it from front to back. As soon as you get through, the whole thing goes away. And then we have our completed tenotomy. And there’s a tendon just laying there. There are lots of attachments from this tendon to the superior rectus. All of our tissues — so these things don’t just disappear. That’s why I think it is, if you’ve had a failed superior oblique tenotomy, it’s probably worth going back and looking at that again, repeating the traction test, seeing if you can feel that tendon still, and if you can feel the tendon still, on the traction test, I would go back and do a repeat tenotomy. So let’s look at what a post-tenotomy looks like here. Same thing. Same view. Cutting through that tendon. Now we’re through the entire width of it. Just gonna push things back in position. And before we close up, we’re going to repeat that tenotomy. So, again, grasping the eye obliquely. This is the right eye here, actually. And you can see that cornea just totally disappears. So this was a bilateral procedure. This traction test is on the other eye, on the right eye, but same thing. Just looking for that — how free that is, now. And so that whole cornea, basically, disappears up into the fornix at this point. Get that video off. I can hear it rolling again. Okay. So back to… I’ll talk about this guarded tenotomy, and we’ll go through the superior oblique video. And then I’ll take the questions that you might have on superior oblique tenotomies and A-patterns, before we talk a little bit about superior oblique palsies. All right? So a guarded tenotomy. A guarded tenotomy is a way to control overlengthening. You can see that when you do a tenotomy, those ends pull apart. How far apart they pull you don’t know. And in some cases you can create a superior oblique palsy, where you had a Brown syndrome before, simply by overlengthening. So ways to avoid this — people have tried different things. You can take what you call a chicken stitch, a suture, make a length to it, to join the tendon ends together, also you can use sections of a silicone expander, 240 retinal band, and a prolene suture. You can see it’s been embedded in here. Some better views here. When we put these in, whether it’s a retinal band or a chicken stitch, it’s usually in the range of 3 to 8 millimeters. Usually you can see what’s been done — before the tendon was cut, or here it actually looks like this… Before the tendon is cut, the suture has been preplaced. And then we’re gonna cut in between, and sew the retinal band in between those two cuts. Let’s look at that a little more carefully. So once you’ve preplaced those prolene sutures in the superior oblique, measure out how much band or suture you want. And then you can see the prolene is being placed through the ends of that silicone band. And then these are the ones that are preplaced in the tendon already. And that band section now is sutured in. So giving a very controlled lengthening, and by preserving that sheath as much as possible, you’re trying to cover this back up with the sheath of the tendon, without creating a lot of scarring. And so that’s the reason why we’re so careful about not just opening up all of that superonasal quadrant and creating a lot of scarring, because we want this to be a functional superior oblique. We don’t just want it to be a scarred mess. And that’s the reason, again, for a very careful technique and preserving that tendon capsule. So we’re gonna look at a video here. And I’m gonna slow this down just a touch. And then we’ll go to your questions on this. Let me slow this down. All right. There we go. So, again, here we are in the superotemporal quadrant. Measure back about 8 millimeters. We had our conjunctival incision. And now on a perpendicular incision, we’ll make our incision through the Tenon’s capsule. You can see we’re staying somewhere in the middle here. Not getting too far back into the fatty areas. We’re bluntly dissecting into the superotemporal quadrant so we have a nice area to slide our hooks into. I start with a small hook, Stevens hook, and plant the tip of it on the sclera and try to get right behind the insertion of the superior rectus. Once you have that small hook in place, you can go with a little more aggressive larger hook to try to make sure you have the entire width of the superior rectus. That’s what we want. The whole width of the tendon. So I’ll usually pass a couple hooks when I do this. And now we’re gonna reflect that conjunctiva up over towards the nasal side. Because that’s where we’re going to find the tendon. The tendon is very condensed on the nasal side. So that’s where we’re gonna do our work with it. It’s very flared out on the temporal side. So it can be very difficult to locate out there. So here we’ve got our retractor in our Tenon’s and conj, replacing one of our hooks here, but the Desmarres retractor is holding back conjunctiva and Tenons, we’ve got condensation here, and picking up the condensation on top of the superior rectus and gently buttonholing that until you can see the surface of the muscle. You don’t want to cut into the superior rectus, but you can see it’s not so filmy anymore. It’s pink muscle we’re looking at. A couple of Stevens hooks placed in there, open that up a little bit, and move the Desmarres retractor into that zone that we just opened up. And here you can see very nice exposure of that superior oblique tendon. So meticulous care with this good surgical technique, so that you have a nice healthy tendon that’s still in the capsule here. So that things are protected from scarring. Now we’re gonna elevate that with the Stevens hook again, going from the back side, along the nasal border of the superior rectus. All right. So here it is in the capsule still. We want to open this capsule up gently. See how we’re using a small tooth forceps and exposing that surface of it. Not opening all of the capsule. Just the surface. Now if you want to do a tenotomy, you can do a tenotomy right there. If you wanted to do a silicone tendon expander, you can go ahead and preplace your sutures before cutting this. One set of sutures here on this side, another set on the other side, and then cut down in between. So this approach is the same. Up until this point. And it looks like we’ve got all the tendon here. That looks like a pretty good superior oblique tenotomy. But keep in mind you always want to repeat your traction test, and confirm that it really feels like it’s completely gone. Just like with the inferior oblique, sometimes if you don’t have it hooked all the way, you’ll get residual function. You can see how that cornea is just disappearing up there, supranasally. So we can be pretty certain that we have a complete superior oblique tenotomy here. All right. I’m gonna go ahead and open up your questions here. I’ll just leave this question up here first. But first, let me go to some of your questions… All right. We have a question here about A and V-pattern shifts. And the question is: what determines the direction of the shift, either up or down, when you’re shifting horizontal rectus muscles? What determines the pattern of the shift up or down? This particular example… We’ve been talking about A-patterns. So you have a pattern that is like this. So you have an A-pattern, which is a very large A-pattern like this. Now, what determines the direction is, if you’re working on a medial rectus muscle, you’re gonna shift it to the apex or the top of the pattern. The top of the triangle of the A. If you’re working on a lateral rectus, you’re gonna shift that towards the empty space, which is down towards the bottom. So that’s what determines the direction. Another question here from Dr. Lowend: what do you think about tendon thinning near the trochlea for Brown syndrome? So this is another technique of shaving down the superior oblique tendon. Kind of thinning it down, so that it either slides into that sheath better, or it may just be that by cutting the fibers, that you’re lengthening it that way. I don’t have a lot of experience with that. I know that it’s been recently rather a hot topic. But whether or not that’s an effective long-term treatment — I can’t really speak to that. I’ve not been unhappy with tenotomies. I doubt that thinning it down — that probably would be reserved for probably a pretty mild Brown syndrome, I would think. All right? Question here — do you cut the superior oblique muscle in the nasal area? Well… We’re approaching it from the temporal side. But when we cut the superior oblique, we are cutting it actually in the nasal quadrant. So it’s most easy to find that tendon along the nasal border of the superior rectus, and that’s typically where we’ll make the cut. If you really have a tight, tight, tight tendon, then you can cut it closer to the trochlea. Question from Dr. Wynn: when do you prefer a superior oblique tenotomy, versus a superior oblique expander? For me, a lot of this depends on the traction test, as well as the magnitude of the deviation. If you have someone who gets a huge hypotropia, when they try to look in the opposite direction from their Brown syndrome, and you do a traction test, and you can barely move that eye up and in, that’s someone who I think definitely deserves a full tenotomy. However, if you have someone with a more mild Brown syndrome, and they just have some problems with elevation, but they’re having diplopia or they’re having problems with face turn, that’s someone whose symptoms are much more mild, and therefore what you don’t want to do is you don’t want to overcorrect them. So that’s someone that I probably would do the silicone tendon expander on, or as someone else has suggested, maybe doing the shaving down of the tendon, to get some better motility there. next question is when doing superior oblique tenotomy, what advantage does the superotemporal incision have compared to nasal incision? When you’re approaching the superior oblique, you can approach it in three different ways. You can go from the temporal side, superiorly, the nasal side, superiorly, or just do a lingual incision and reflect all of that. All of those are good. Coming from the temporal side is probably the most difficult, but it’s also probably the cleanest. Because all your scarring is being kept over in the superotemporal quadrant. You’re having very limited scarring or disruption of the tissues in the superonasal quadrant. This is particularly important when you’re talking about doing something like a silicone tendon expander. You don’t want all of that stuck together. So superotemporal silicone tendon expander — that’s probably when it’s most important. Otherwise it’s probably whatever is gonna be most comfortable for you. It’s always easiest to find along the superonasal border, just because it’s more condensed there, though. All right. So let me go back to our presentation here for a bit. And we can bring the poll questions back up here for a minute. All right. So poll questions… The question was: what do you think is the most common cause of head tilts and vertical diplopia in adults? Nystagmus, thyroid myopathy, inferior oblique palsies and superior oblique palsies? Most of you have that down. Any time you see someone with a vertical deviation, head posture, head tilt, it’s pretty much a superior oblique palsy until proven otherwise. It’s a very common thing. So understanding this and keeping is simple is important for that reason. We’ve covered some of this in the advanced complex strabismus webinar that we did previously, so I may move through some of this relatively quickly, in the interests of time, so we can keep taking questions here. Again, most common cause of head tilts in oblique diplopia. And these can be scary patients. And by scary, I mean intimidating or difficult, particularly if you’re a part-time strabismus surgeon. Most of these that we see seem to be congenital. And when we say palsy, we really don’t mean so much for the congenital ones — it’s usually not a cranial nerve palsy. It’s usually confined to the superior oblique tendon and trochlear complex. The muscle, because it’s the longest one, it’s prone to being too long or too short. Too short gives you Brown syndrome. Too short gives you palsy. But you can have palsies of the cranial nerve, vascular, trauma from ENT procedures, so it certainly can happen. How do you make the diagnosis? Well… Kind of a straightforward, step by step thing that I do, every time I see one of these patients — we’ll touch on each of these four areas. Versions, three-step test, torsion, and then the FAT scan. Pretty typical patient here. When you’re looking at the versions. This is her primary position. And we don’t know what her measurement is here, but she’s got a little more sclera showing on the right eye compared to the left. Probably 10 to 15 prism diopter hypertropia. And you can see she’s not fully in right gaze, but looks pretty good. But on left gaze, she gets more of a right hypertropia. So this is where we start to apply our three-step test. Three-step test — the very first thing I do is kind of write out what you see right here on this grid. We’re gonna write down all four of the vertically acting muscles for each eye. And their kind of position of gaze. Superior rectus, up and out, inferior rectus, down and out, so just flip the paper over. I write these down like that. And then identify — which eye is the hypertropic eye? And I want to remind everybody that when we abbreviate things, we frequently see people writing down RHT, LHT — that to some people can mean hypertropia or to other people a hypotropia. The accepted nomenclature is that you always identify the eye which is the hypertropic eye. So RHT, right hypertropia, means that the right eye is the one that is elevated. And that can get confusing, when people are fixating with the palsied eye. And it looks like they have an opposite, a left hypotropia. But always document relative to which eye is the higher eye. So this lady has a right hypertropia, 15. The very first thing we want to do is mark out which muscles could be causing this right hyper. So a right hyper can be a weakness of both the depressors on the right eye. Inferior rectus and superior oblique. So we circle those. A right hyper is the same as a left hypo. So it could be that the left eye is just too low. So it could be a weakness of the elevators on the left eye. So we circle those. Now, in right and left gaze, we need to identify where the hyper is worse. And here you can see that she’s worse in left gaze. So she’s got a right hyper, worse on left gaze. So we need to look at the muscles that work in left gaze. We’re circling the elevators that work in left gaze on the right eye and the elevators that work on the left gaze in left eye. The final step here is identifying where the head tilt makes the strabismus worse. This lady likes to have this head tilt on the left side. She does not like this head tilt on the right side, because she gets a right hyper. So looking where her right hyper is worse, simply duplicate what her head position is. Here I’ve circled the superior rectus and superior oblique and inferior oblique and inferior rectus. You don’t have to understand the mechanics. Just follow the hypertropia. And when you follow this, you can see they intersect at the superior oblique. So what we thought — a right superior oblique palsy. There are perversions of the three-step test. A lot of things like prior surgery, restrictive strabismus, thyroid — all these things can throw the three-step test off. So keep that in mind. If any of these other things are — it’s still useful to do, but it’s not quite as automatic as it is when you have these other existing factors. One of the biggest gaps that I see when visiting people is not measuring torsion. Torsion is important not only for making the diagnosis, of a unilateral palsy, but it’s really important when it comes to the diagnosis of a bilateral palsy. This might dictate doing the correct surgery versus the incorrect surgery. Double Maddox rod, put the lenses in a trial frame, you can see the lenses are going up and down. That means the patient sees a horizontal perpendicular bar. If they have some torsion, they’ll see the white and the red, but they won’t be parallel. One will be tilted. I have them reach up and just adjust things until it lines up, and made them like railroad tracks — that’s how I describe it to them. And then we put little pencil marks on the frame of the double Maddox rod, and as long as things are lined up, you can then read the amount of torsion right off the frame. So this particular person, there’s 95, 97… So this person has about 7 degrees of torsion. Now, for people who don’t have double Maddox rods, or you have a child and they can’t cooperate, you can assess torsion objectively. This is the fundus photograph — normally fovea sits just at or below the center of the optic nerve. Pretty straight across, maybe a little below. Keep in mind when you look with your indirect ophthalmoscope, things are reversed or side to side. So now the fovea should be at or slightly above the center portion of the optic nerve. Right? And again, here’s an indirect ophthalmoscope view, with the right eye where it should be, in the middle or upper third of the optic nerve. Clearly once that gets above the level of the optic nerve, you clearly have torsion. Here’s a person who has bilateral superior oblique palsy. And you can see that the foveal marker here right here — just above the border of the optic nerve. So this person has bilateral excyclotorsion. These people can have very little torsion. Acquired palsies almost always have a lot of torsion, and bilateral palsies — these are what you’re really looking for, which have more than 10 degrees of excyclotorsion. Facial asymmetry. This is what you’re looking for. This can differentiate whether it’s a congenital or acquired palsy. Someone has a longstanding head tilt, they’ll get decreased distance between the canthus and the corner of the lip. If you see an adult with facial asymmetry, you know this is not a new palsy. They probably had it since they were in childhood. And there’s that shadowing on the downhill tilted side of the face. How do you know if it’s new or not? A lot of times people don’t recognize this. You can have them pull out their driver’s license or identification. If they have a license like this, from two years ago, and their head is straight, but now you’re seeing them with a head tilt, you know this is an acquired palsy, and that person probably needs to have a neurologic workup. So surgical planning. This depends on the magnitude of the deviation. The versions, torsion, whether it’s contracture, and then the tendon laxity. when you get superior rectus contracture — this person had a left palsy for a long time. So now when they look down on the side of their palsy, the other eye is overfiring, because this inferior rectus is working against a constricted superior rectus, which makes this one look like it’s overacting. That’s how you can start to look for superior rectus contracture. It’s not real common. Grading of laxity. This is anywhere from -1 to -4, and it’s relatively subjective. You need to do traction testing on normal eyes before you go in and start doing a superior oblique palsy eye, looking for laxity. You need to have some perspective on that. Grasp the eye obliquely. Left eye, right eye, push the eyes up and in and roll them across that tendon. You can see there’s a difference on this, just visually without even seeing it rolling — this cornea is still visible. This one is not. And then when you look at that patient, look at the tendon — kind of normal at the left side and look how redundant the tendon is on the right side. So laxity is almost exclusive to congenital palsies. And it’s good to be aware of this, because if you have a really lax tendon, this is the one that needs to be tucked. Superior oblique surgery on its own is probably not gonna be sufficient. We’re drawing short on time. I’ll try to get to this as best we can. If not we’ll do a part two. When you select muscles, you want them to have their effect in the area of greatest deviation. So single muscle surgery, for me, if the deviation with the superior oblique palsy is small, 15 prism diopters or less, then usually what I will do is just weaken that inferior oblique, whether a recession or a myectomy. That will almost always give you what you need if you have these mild deviations. If you don’t have inferior oblique overreaction, you can go to the contralateral. And I’ll do that if I have a larger deviation. So more than 15 prism diopters, I’ll weaken the inferior oblique on the side of the palsy and go to the other eye and assess the contralateral inferior rectus. How do you estimate how much? Well, the inferior oblique myectomy or recession will give you up to 15 prism diopters of correction, and then based on 3 millimeters… Rather, 3 prism diopters of correction per millimeter per recession, that’s how much I’ll recess the other inferior rectus. If you have more than you can get comfortably with that, more than 15, maybe you need a third muscle. So this is when tendon tucking and superior rectus recession can come into play. All right. I’m going to switch this… Skip this poll question, in the interests of time. One warning on superior oblique palsies. If you’re uncertain about how much to do, undercorrect these patients. And the reason is they usually have very large vertical fusional amplitudes, but it’s one direction. If you overcorrect them and they have to do it the other way, they don’t do it well. They’re miserable and have a lot of diplopia and you have to do something to fix that. So undercorrect rather than overcorrecting. Here’s an illustration of tucking. This is a tendon tucker, but you don’t need that. You can elevate the oblique at its insertion with a muscle hook and place a couple non-absorbable sutures across the border there and you can cinch that down. That effectively tightens. Gives you a resection effect for that tendon and makes it tighter, makes it stronger. We’re on the hour. So I’ll keep going. But I’m going to touch on the questions first. In case some people need to sign off. I realize this is a little bit longer than I wanted it to be. Going to the questions… Here’s a question about… What do you think about results without binocular vision in superior oblique palsy? Well, I think any time someone has binocular vision, their chances of maintaining fusion and having good outcomes are better. The nice thing about superior oblique palsies is that most commonly the ones you see are these 10 to 15 prism diopter vertical deviations, and doing a straightforward inferior oblique myectomy or recession really fixes those people in about a ten minute procedure. So the smaller — it really comes down to the magnitude. The smaller ones I think are very easy to fix. When you start getting… There’s another question that we have, this patient — this is from Dr. Bamari, who has a patient with a 50 — five-zero prism diopter exotropia and hypertropia of 45. So now you’ve got something that’s really complicated. Really large deviations. When I see somebody with a hypertropia of 45, that’s someone that I’m gonna really look at their traction test, because that is someone that probably is a good candidate for superior oblique tuck, if the tendon is lax. The exotropia that you frequently get with these — you just have to deal with that as you would… I would still go ahead and recess your laterals or resect medials as needed to treat your exotropia or esotropia, as the case may be. So that’s all the questions that we have going right now. I’ll go back to the presentation, and keep moving through this. Bilateral palsies — I’ll touch on for a minute. So these are people that have complaints of torsion. And subjectively, they’ll tell you that things look slanted. Things that are vertical, like door frames. They’ll have lots of measurable torsion. More than 10 degrees. They’ll have this chin-down posture. This is very classic. Like this gentleman has, and that’s because they have a V-pattern esotropia, and with the chin down, they diverge their eyes and become binocular. They’re doing it to avoid diplopia. And they’ll have hypertropias, left on left head tilt, right on right head tilt, but not always. The reason you always want to identify superior oblique palsies that are bilateral is because the treatment is significantly different from the unilateral palsies. Unilateral palsies you’re usually doing something with inferior oblique. But that’s not as effective with these. So we’ll collapse the V-pattern, things like medial rectus recession, downshift, and then we get into things we do to correct the torsion. Harada-Itos, nasal transpositions, superior oblique tucks. It becomes very complex. And that’s why measuring that torsion is so important. Nice thing — probably my go-to thing with the bilateral palsies is to weaken the yolk muscle of the superior oblique, and that’s with the inferior rectus on either side. I’ll recess those 5 to 6 millimeters, and you can do those asymmetrically. Because the superior oblique palsies are bilateral, they’ll have very small vertical deviations or none at all perhaps in the primary position. If you do have one, you can recess the inferior rectus asymmetrically. So I might do more recession on the right than the left, trying to collapse that. I want to touch on Harada-Ito. This is the original description, where the anterior fibers are diverted on the superior oblique. And the reason we’re looking at the anterior fibers is the anterior fibers of the superior oblique are the ones that primarily do the rotational function. The posterior fibers are doing more of that vertical function. So by strengthening or tightening these anterior fibers, you produce more incyclorotation. The more commonly performed version of the Harada-Ito is the Fells modification. We insert half, preplace the suture, and disinsert it. That gets it down close to the superior border of the lateral rectus. Displacing it posteriorly about 8 millimeters. So this would be the most typical position. Some people would actually do these on adjustables. So it gives you a lot of ways that you can control this. And then again, just by advancing that, those anterior fibers, you’re inducing more incyclorotation. Well, how much do you get? We’ve studied this. And I’ll just go straight to the results of the study. The results were pretty much that the average… This is for doing a unilateral Harada-Ito — on average was producing about 8 degrees of incyclotorsion. If you do a bilateral Harada-Ito, the result was more in the ballpark of 12 degrees of incyclotorsion. We see people with more torsion than that, and this is the reason that subsequent surgeries are sometimes need more more torsion. You can get a fair amount. If you get them close, most people do okay. It’s just the larger amounts that they don’t tolerate. I’ll give a shoutout to Orbis Cybersight video library. There’s a very nice demonstration of a superior oblique tuck from Dr. Rao. I won’t show that today, since I’ve already run over by about five minutes. But you can find the video library at Orbis Cybersight, and a nice superior oblique tucking video. It has some nice animations too. It’s just a nice surgery video in general. So check that out. Orbis Cybersight, of course. I won’t go into the consult function. Touch on that some other day. But I want to point out a couple new things. One new thing is that you’ll notice that we’ve added closed captioning. Subtitles. To the webinars. And so the recorded webinars will be available on Cybersight, with the subtitles. That way if it’s a little difficult to understand what’s being said, you can go back and review this, at a slower pace. Again, I apologize for kind of picking it up in the last 15 minutes here. A couple other things I want to point out. This community activity. So now you can follow to see who’s doing cases. You can follow to see if they’re public or private cases, and the public cases you can actually view, and see what advice is being given to our users. Another thing is… We have this discuss feature. Which is not too new. But it’s relatively new. And if you go to the discuss feature on Cybersight, it’s kind of like a discussion forum. Different topics. And you can see that we have topics available for cataract and IOL, corneal and external disease, even things like international fellowships and educational opportunities. Equipment, bioengineering, tricks, if you have tricks about smartphone technology, how to take fundus images, refraction, and then of course what we’re doing today, pediatric ophthalmology and strabismus. So if you have a question that you want input from someone, maybe other than one of the Orbis faculty, you want someone else, one of our users, take advantage of this. It’s a great way to share techniques that we all have. Little tricks and tips out there. And it’s a great addition that I’d like to see used more frequently. All right. And before we depart, I will take one more look at our questions here. Dr. Nack, Vietnam, has a question about — what do you do with a patient who has a congenital absence of the superior oblique tendon? Not a common condition, but it does happen. You can’t make a new tendon. So I don’t know if I can give you an absolute answer. But in general, identify muscles that are acting in that area in the direction where the deviation is greatest. So this is where you’re going to need to go to the contralateral inferior rectus, you’re going to need to maybe do the ipsilateral superior rectus. Anything you can do to collapse that. But I don’t really have any tricks for replacing the tendon. Dr. Heiermat has a question. When will you operate on acquired superior oblique palsy? It depends on when it was acquired from. If this was a trauma or a surgical procedure or something definite like that, I would treat that — probably not do anything for six months. And if they were showing signs of improvement, I would wait up to a year to see if the acquired palsy resolves. If they weren’t getting any better, maybe after six months, I might start looking at the surgical options. Dr. Tandil has a question about… Do you get the superior oblique muscle from the temporal field in Harada-Ito? Yes. So taking the muscle from the temporal side is usually easiest. You can hook the superior oblique from the temporal side. Sometimes it’s difficult, because the tendon is fanned out there. If you can find it and hook it easy, that’s straightforward, because you’re advancing from the insertion anyway into the temporal quadrant. If you can’t find it and hook it, though, there’s nothing wrong with doing it just like you’re doing a tenotomy, isolating the superior oblique tendon, and what I’ll do is usually put a silk suture around the tendon from that nasal side, pass it under the superior rectus, so that I am identifying all of the insertion, and then working on the insertion. The other thing some people do — some people take the superior rectus off, so they can see the superior oblique, and then put it back on, after they’ve done their advancement. All right. So I appreciate everyone’s time today. If your question didn’t get answered, I’ll try to post the answers, as we post this recorded webinar. With the closed captioning. This will be our last one for the year. Starting up in 2017, we’ll continue with this series, and so if you have any requests for lecture topics, please write to us, and let us know. [email protected] Or go to Cybersight and use the link there.
December 12, 2016