This lecture will continue our discussion of advanced surgical planning and techniques for complex strabismus cases. Part I discussed surgical approaches to the Inferior and Superior Obliques. Part II will finish our discussion of bilateral Superior Oblique Palsies and continue on with other forms of restrictive or paretic strabismus including: Duane syndrome, thyroid myopathy, fibrosis syndrome, 3rd and 6th nerve palsies, BOTOX injections, and adjustable suture strabismus surgery.
Lecturer: Dr. Daniel Neely
DR DANIEL NEELY: So in part one of the complex series, we covered the inferior oblique and we covered the beginning of the superior oblique. Where we left off was having to do with torsion and bilateral nerve palsies, so that’s where we’ll pick up. And then as the hour goes on, we’ll get in through 3rd nerve palsies, 6th nerve palsies, Duane syndrome, and kind of other restrictive forms of strabismus, particularly the thyroid myopathy, and then I want to talk about Botox, because that’s a common issue that comes up, as well as adjustable sutures. So it’s actually a very interesting session that we have ahead of us here. Now, when we were talking about superior oblique palsies, the thing that came up that really differentiates bilateral palsies from unilateral palsies is torsion. And so while with unilateral palsies, you get these head tilts like this, with bilateral palsies, we have something more like this. See this gentleman? He didn’t really have a head tilt, but he’s got this chin-down posture. And this all comes back to the unique characteristics of these bilateral palsies. And so I want to talk about torsion. Because, again, this is really what differentiates it. Being able to do a test with a double Maddox rod is really key to distinguishing a bilateral superior oblique palsy from a unilateral superior oblique palsy. When the patient is looking through these two Maddox rod lenses, this is what they see. They see a white line through the white one and a red line through the red one, and again, you can see the lines are directed perpendicular to where they are on the lens. And by letting them line them up perpendicular, if they perceive them as not perpendicular, as in up here — once they line them up perpendicular, then you can merely look at the trial frame, right here, and you just simply read the amount of torsion right off the trial frame. So here this patient should be lined up at 90. She sees it level when it’s more over at 95. So she has 5 degrees of excyclotorsion. Now, torsional pearls — again, this really helps you differentiate unilateral from bilateral palsies. The congenital palsies typically have little or no torsion. So less than 5 degrees is pretty typical. That’s different than acquired palsies. Acquired palsies always have significant, measurable excyclotorsion. In the range of 5 to 10 degrees. What you’re really looking out for are these bilateral palsies. These are the people who come in complaining of torsion. They complain of door frames looking slanted, and they will typically have 10 degrees or more of torsion, which is measuring on double Maddox rod testing. And also on their fundus exam, you can see torsion of the fundus. Now, this gentleman we looked at before — again, these are the hallmarks of bilateral palsies. He’s got this chin-down posture. Why do they get that? That’s because they typically have this V pattern esotropia. So they are trying to spread their eyes apart by dropping their chin down and bringing the eyes out. Again, spontaneous complaints about excyclotorsion. And then the other hallmark is this alternating hypertropia. They get right hypers on left gaze and right head tilt and they get left hypers on right gaze and left head tilt. So we’ll talk about that. You don’t have to take that all in yet. But here’s a nice case study. This is a young lady who had surgery for pilocytic astrocytoma of her cerebellum. She had surgically-induced bilateral 4th nerve palsies as a result of her surgeries, and then had spontaneous complaints of diplopia immediately after surgery. When you look at her motility, she has what you would expect to find. She’s got some weakness of the superior obliques. And as a result, she has overaction of her inferior obliques. And as is typical, most of these bilateral superior obliques palsies don’t have much hypertropia in the primary position. Here you can see she’s got only three. But what you find is this alternating hypertropia. So on right gaze, she gets a left hyper. And on left gaze, she gets a right hyper. Now, typically you’ll see that reflected in the head tilt testing as well. Here she just has a difference in the hyper, of the right hyper. That probably is attributable to her palsy being a little bit asymmetric, perhaps. What she does have, though, is this V pattern esotropia. Here you can see upgaze, 6 prism diopters esotropia, 18 in primary, and then up to 22 in downgaze. And then look at this. 25 degrees of excyclotorsion. You don’t get that on a unilateral palsy. All right. So this is typical. Anywhere from 10, 15, up to 25 degrees of excyclotorsion. That’s a bilateral palsy until proven otherwise. And the reason you want to measure that is because frequently these are asymmetric. As this one is, a little bit. But even more asymmetric. And it can look like a unilateral palsy, until you operate on it, for a unilateral palsy, and then all of a sudden you’ve unmasked the other side, and now they appear to have inferior oblique overaction on the other eye. Well, you can be aware of that if you have, ahead of time, measured their torsion, and you know that they have too much torsion for what you would expect in a unilateral palsy. So that’s really why Maddox rod testing is so critical, and understanding the torsional aspects. Now, here’s her motility again. You can see her left inferior oblique overaction on right gaze. And then she’s got reverse right hypertropia on left gaze. And they’re asymmetric. So she has an asymmetric palsy. Now, so this is a bilateral superior oblique palsy. This is our next poll question. I want to know — how would you treat this palsy? Because, frankly, there are a lot of different ways to treat these. I’ll see if I can get our polls to pop up. They’re being a little stubborn here. Here we go. Okay. So now the polls are up. How would you treat this palsy? Poll number 2. We’ll launch our poll. Okay. Bilateral superior oblique palsy. Would you weaken both inferior obliques? Perhaps tuck the superior obliques? Or recess the inferior rectus muscles? Or a bilateral medial rectus downshift? Or some combination of any of these? All right. Looks like most of us have voted at this point. And you can see these are a lot of diverse choices. And so I think we’re gonna see a lot of diversity in the responses here. And when we talk about it, I’m gonna give you a diversity of answers. I’m gonna end the poll and I’m gonna bring up the results now, so we can all see. So here’s what all of us in the audience thought. What would you do? Well, bilateral inferior oblique weakening. It seems logical, right? Unilateral palsies. You typically weaken the inferior oblique. Bilateral palsy — why not weaken both inferior obliques? Superior oblique tuck. Superior oblique is weak. Why not tuck it? Inferior rectus recession. This is something we’ll touch on, because this is one of my favorite treatments. MR downshift — no one went for that. And then combinations. Of course, combinations can work. Sometimes you need more than one thing in order to get enough effect. Let’s continue on with our polls. Or with our slides. All right. These are the treatment options for bilateral superior oblique palsies. And you can see why we had a lot of different answers on our polls. There are a lot of treatment options, but pretty much all of them have the same goal in mind. You need to find something that’s gonna collapse the V pattern. You need to nullify any primary position hypertropia that there is. And you need to reduce the torsion. And look at all these options. All these tools in our tool box that we have. Now, what are my favorites? Well, my favorites are inferior rectus recession, combined — maybe doing that asymmetrically, for any primary position hypertropia, and then adding in Harada-Ito. Now, why do we have these options? Well, you know, inferior oblique weakening is probably the easiest thing to do. But frequently it’s just not enough. It doesn’t give you enough torsion effect. It may not give you enough control over primary position deviations. Okay? If they have a right hypertropia that’s asymmetric, how are you gonna do that, if you’re weakening both inferior obliques? So it gets a little bit complicated. That’s where the inferior rectus procedure comes in. So it may be more effective to weaken the yoke muscle to the superior oblique. So if we’ve got a left superior oblique palsy, that means it’s problematic down and gaze to the right. So the yoke muscle to the left superior oblique would be the right inferior rectus. So why not weaken that and try and balance that out? These bilateral inferior rectus recessions — if you recess the inferior rectus 5 to 6 millimeters, that has a nice effect to collapse the V pattern that we have. And you can do that asymmetrically, so you can compensate for that primary position difference. And keep in mind that for about every millimeter of difference in where you place those, you’re going to get about a 3-millimeter or 3 prism diopter correction in that primary position hypertropia. And I’ll demonstrate this to you with the case that we’re talking about. And then the Harada-Ito. This is a nice way to control the excyclotorsion, and we’re gonna go through that. So in our case study that we had, she had a bilateral superior oblique laxity. Interesting to find on her traction testing. Because usually we think of laxity as something with congenital palsies. And so to have it on an acquired palsy, not real typical, but it can happen. She had this primary position deviation of 3 prism diopters. So we did this asymmetric inferior rectus recession. More on the left side, because she’s got a right hyper. Try and collapse that out of there. And then for her torsion, we did this bilateral Harada-Ito. And let’s look at that, because the Harada-Ito is a very useful, very interesting, and I think perhaps maybe underutilized procedure for many of us. Now, the classic Harada-Ito, as originally described, involves splitting the superior oblique tendon, separating the anterior half of the fibers from the posterior half of the fibers. Now, the reasons for that — these anterior fibers of the superior oblique are largely torsional. Now, the posterior fibers have more to do with the vertical deviation, and vertical effects of the superior oblique. So we’re taking advantage of that by changing only the anterior torsional fibers of the superior oblique. Split the muscle. Put a suture around it. And then shift that about 3 millimeters anterior, and 3 millimeters temporal, and this diversion of those anterior fibers was what was originally described as the Harada-Ito. Now, most of us think more of the Fells modification of the Harada-Ito. Again, split it. But then you put a suture into that anterior half, and you move it forward. Or you move it lateral. So you’re taking it sagittally down here, and you’re gonna suture that anterior torsional — those anterior torsional fibers — about 8 millimeters behind the insertion, and just above the superior border of the lateral rectus. So this is the Fells modification of the Harada-Ito. And here’s what it does. You’ve advanced these torsional fibers, so now these are pulling more, and so you’re gonna get incyclorotation inducement of the globe. I would say you’re compensating for the excyclotorsion by producing more incyclotorsion. And that will correct anywhere from 10 to 15 degrees of excyclotorsion in the primary position, if done bilaterally. Sometimes you can get more. All right. So this is where we — I’m gonna check in on our questions and answers. If you have any questions about bilateral superior oblique palsies, torsion, it would be a great time to ask those now. We do have a question about congenital 3rd nerve palsy, but I will wait and take that when we get to that section, which is coming up. So currently no questions about superior oblique palsies. If you have one later on, I’ll be happy to answer that. But I’m going to go on and just double check… We do have one question here, which is how to access the superior oblique. My typical approach to the superior oblique is, as we talked about in our last lecture, complex strabismus part I, and that’s a superotemporal approach — and especially in this particular case, where you’re going to take the tendon even more temporal, that gives you direct access to that. All right. So I’ll continue on with our lecture. Let’s go into Duane syndrome. I think Duane syndrome is really a fascinating topic, and when I answer consults, this is probably in the top 5 questions that we get in the strabismus section. Duane syndrome — what’s typical about these? Well, they frequently have little, maybe no esotropia, or very small amounts of esotropia in the primary position. Here you can see this child looks pretty well lined up, despite having a very limited abduction in this left eye. Now, if this was a 6th nerve palsy, you wouldn’t be walking around like this. An abduction limitation like this with a 6th nerve palsy — this person is gonna have 35, 45 prism diopters of esotropia in the primary position. So that’s one way you can know that it’s a Duane syndrome, rather than a 6th nerve palsy. Another characteristic of Duane syndrome — this is a type I case that we’re looking at now — this patient is getting an upshoot here. And this limitation here might suggest that it’s a type III. But this upshoot we’ll talk about, because these are also characteristic of several of the Duane syndromes. Enophthalmos and globe retraction. This is the other hallmark that can really help identify Duane syndrome versus a 6th nerve palsy. Here’s this young lady in the primary position. And now she’s going to attempt to look to her left. So looking away from us. And look how the fissure narrows. And that’s because the globe is being retracted, as the medial rectus pulls against this restricted and non-innervated, non-relaxing lateral rectus. So that’s really a nice hallmark to help you differentiate Duane syndrome. Now, when do you surgically intervene for Duane syndrome? It’s not automatic. This is like Brown syndrome. Just because they have the problem doesn’t mean you need to operate. You need to decide who’s a good candidate for surgery. Well, if you have strabismus in the primary position, that’s a good reason to operate. If these people have abnormal head postures, so typically they’re going to have face turns. If I have a left Duane syndrome and my eye won’t go to the left, then my face is gonna go towards the left, to kind of take that muscle out of play. So people will usually turn their face toward the paretic muscle. And if they significant upshoots or downshoots, of course you’re going to want to fix that as well. All right. So before we talk about surgical management of Duane syndrome, we’re gonna go back to our polls. How do you treat Duane syndrome? I’ll go ahead and open this up and read through these. So typical type I Duane syndrome, like the patient we just showed — deficient abduction, a little bit of esotropia in their primary position. You can recess the medial rectus on the esotropic Duane’s eye. You can recess both medial rectus muscles on the Duane eye and the contralateral normal eye. You can do a recess/resect on the Duane eye, just like you would for any esotropia, and then we have the option of a full tendon transposition of the superior rectus and inferior rectus towards the lateral rectus, like you might do for a 6th nerve palsy. All right. And let me share the results of that with you. And again, we have a diversity of answers here. Most of you would recess the medial rectus on the affected eye. Frankly, I think that’s the easiest and probably safest thing to do. Another nice percentage would do these bilateral medial rectus recessions, and we’re gonna talk about that, because particularly if done asymmetrically, it can be a nice technique. Recess/resect. Stay away from that. And I think most of you did. You almost never want to resect a restricted muscle. And basically a Duane syndrome type I — lateral rectus is going to be a restricted or poorly innervated muscle. So we almost never want to resect those. It’s not often that that’s a good option. Full tendon transposition can be a good option. But has some pluses and minuses that we’ll touch on. All right. A lot of you liked this first option. The single medial rectus recession. Moderate. Usually about 5 millimeters is what I would do for most Duane syndrome patients with small to moderate esotropias. By recessing that medial rectus, instead of being restricted in turn like this, they’ll be able to get their face relatively straight. So you almost can’t lose with that. It’s very tough to overcorrect a Duane syndrome patient. However, you can use that to your advantage. Because it’s so difficult to overcorrect them, another thing to consider is this asymmetric medial rectus recession. Now, you do your standard recession on the Duane eye, so maybe you’re gonna do 5 millimeters on this one. And then on the normal eye, you’re gonna do a larger recession. You’re gonna recess it 6 or 7 millimeters, maybe. What’s that going to do? Well, that’s going to make it harder for the right eye to go in. And maybe you’re gonna expand their diplopia-free field over to that affected side. Same thing with the full tendon transposition. Y splitting — we’ll touch on this, because this is a nice way to reduce upshoots. This is an asymmetric medial rectus recession. Again, for the larger type Is, you do this moderate recession, and then this larger recession on what we call the normal eye, right? The non-Duane’s eye. By recessing the normal medial rectus, it’s gonna be harder for the normal eye to go in the direction where the diplopia is. Therefore, they’re going to have a larger field of diplopia-free vision, and you might also be able to drive that paretic lateral rectus, because the medial rectus on the contralateral eye is firing off so much. So you can perhaps drive a little more abduction on the Duane eye. The Y splitting — when you have these upshoots, why do you get these upshoots? Well, let’s go to our whiteboard for a second. And let’s talk about upshoots. So these upshoots happen when the lateral rectus is tight. So if we have a… Let’s clear that. We can do better than that. So if we have an eye, and then this is our lateral rectus here, and it’s tight, right? It’s fibrotic, and it’s like a thin rope — here’s our cornea. Very nice. So now, when this eye tries to go this way, the equator of the globe right here is pressing up against the tight, thin, restricted lateral rectus. And it’s either gonna slide up or down, as you push against it. You can think of this as trying to push a basketball against a rope. That basketball is either gonna go up over the rope or it’s gonna go down below the rope. And when it goes down, when the equator goes above the rope, then you’re getting the eye pushed up. All right? Well, Y splitting… If we have a Y splitting — here’s our eye. There’s our cornea. There’s our lateral rectus insertion. We’re gonna split that lateral rectus and splay it out like this and this. And back like that. Now when this eye tries to go this way, instead of this eye — instead of being pushed against a rope like that, now we’ve got a net, more or less. And the equator gets nestled right in the split, and it doesn’t go up, and it doesn’t go down. Back to our Duane syndrome slide. All right. So if you split the diagram of being Y split, if you don’t need anything, any exotropia control, you can just simply split that lateral rectus with a muscle hook, a Stevens hook, spread it out, about the width of insertion, and then tack it back on, and then you’re creating this little (inaudible) where the equator won’t go up or down. Frequently I use this in the type II Duane syndrome, but those are usually exotropic, and a nice way to assess (inaudible) this lateral rectus with the exotropia — and then Y split it like this, to control the upshoot or downshoot. At this point, wrapping up our little discussion on Duane syndrome… Let’s see if we have any questions about Duane syndrome. All right. So… I have your questions up. We have a question about 4th nerve palsy. Before we go on from Duane syndrome, I will come back to the 4th nerve palsy here. We have a question about where the 4th nerve was cut in the first case, and therefore (inaudible) Harada-Ito (inaudible) well, maybe it’s cut, maybe it’s bruised. That may be — you may be right. That’s so much torsion. And if it’s totally paretic, you won’t have it acting (inaudible) you can see (inaudible) still has (inaudible). Maybe it wasn’t cut. Maybe it was just bruised or compressed. (inaudible) stretched, therefore she did actually have a nice effect. We have a question about torsion in upgaze and downgaze from Dr. (inaudible). I think this is a very good point to bring out. We talked about mostly torsion in the primary position. However, most of these 4th nerve palsy patients have more torsion in downgaze. So it’s very important that you’re evaluating them preoperatively (inaudible) postoperatively — look at their torsion in downgaze. It’s typically improved. A question about grading of the Y split. The only grading of the Y split that I do is the… Is the recession. And I understand there’s some issue with the audio. I’ll try to adjust the microphone. Maybe we can get less feedback from that. Continuing on to restrictive strabismus… In restrictive strabismus, usually what we’re seeing is patients with Graves’ disease, thyroid ophthalmopathy, or perhaps congenital fibrosis. This lady is pretty typical. She has an inferior rectus on the right eye affected. And you can see when she looks to her right, she gets more hypotropic. And she’s still hypotropic on the left gaze. In upgaze, you can see she’s clearly restricted. Her right eye not elevating. As you look at this in right gaze, you can see that she’s worse in right gaze. So here in right gaze, the cornea is mostly below this horizontal line that I put through the canthi. Whereas, if you take her out of the field of action of that right superior rectus, she elevates a little bit better. So it’s typical that they’re elevated in both directions, but as you get out of the field of action of the restricted muscle, they might elevate a little bit better. Back here on the previous slide, here we can see with the translucent occluder — when she’s fixating with her non-restricted eye, the right eye is still hypotropic. But this is a nice teaching point. When she fixates with the restricted eye, she’s getting this very large secondary deviation on the non-restricted eye. And this is because the superior rectus up here is really working hard, firing off, to get this eye up into the primary position. Well, its yoke muscle on this eye, the other superior rectus, is gonna get all that extra innervation too, and it’s really gonna shoot that eye upward, because it’s not restricted. This is why, when we measure paretic strabismus, you generally want the prism to be on the restricted eye, so that you’re not measuring the secondary deviation. Because you’ll be measuring this larger deviation, if you have the prism on the non-restricted eye. So always put the prism onto the restricted eye. General surgical guidelines — well, there’s not a lot of magic to this. If you have a restricted muscle, you need to recess it. You need to weaken it. And so generally you want to identify where the deviation is greatest. This lady would be greatest up and to her right. So we want to recess that antagonist muscle, which is the restricted inferior rectus on this side. Generally speaking, when you have a restricted muscle, like this lady’s got a restricted inferior rectus, just like Duane, you really don’t want to be resecting the antagonist muscle, most of the time. There are very few cases where resecting opposite a restricted muscle is helpful. So in general, we want to recess the restricted muscle. Now, keep in mind that because it is restricted, the surgical dose response is increased. So while I might normally anticipate 3 prism diopters of correction per millimeter of recession, in a restricted muscle, you’re probably gonna get something more like 4, maybe even 5 prism diopters of correction. So the surgical tables that we all use for normal cases really don’t apply in these cases. This is different. This is why some people like adjustable sutures. And it’s also — some people will do things like disinsert this restricted inferior rectus, let the eye center on the table, and then they’d simply suture the muscle back on where the eye is resting, to align it. So different ways to do these. But just keep in mind — it’s not the same dose response as a restricted muscle. Sometimes these thyroid cases or restricted cases are prone to slippage. And that’s what brings me to this bottom point. They’re unpredictable, and that’s why some people like adjustable sutures. On the other hand, they may not heal into position quite as well, and that’s why some surgeons have the converse opinion, and they strictly avoid doing adjustables on restrictive cases, or thyroid cases in particular. You might also consider using a non-absorbable suture because of this slippage problem, and a 5-0 or 6-0 Mersilene is frequently a good choice, particularly if you’re doing large recessions. Now, we’ll go back to our polling. See if you have any questions about restrictive strabismus. I realize that we’re covering a lot of topics here in a short period of time. But I want to make sure that we get to all our good stuff that we have to cover today. This is our last session to wrap up strabismus. Sorry. I’m just having a little trouble getting the questions to pop up at the top of my screen. All right. Come up. If they’re not gonna pop up, I’m just gonna continue on. Tell you what — let me stop the share for a second. See if I can get to them that way. All right. Let me open up the questions here. We had one question about splitting, the Y split. Basically, on the Duane syndrome Y splitting, you’re gonna split it the width of the muscle insertion. And do we have a question about the timing of thyroid-related strabismus surgery? Well, in general, the timing is that you wait until they’re quiet. Some people have talked about and maybe even advocated operating when they’re still active. You run the risk of having them have a flare-up and changing. I tend to treat these a lot like 6th nerve palsies, where I like them to be stable for about 6 months before I operate. Again, sometimes you can get these to flare up, and prone to change. So… A lot of times you’re letting them just kind of do temporary things with occlusion, or Fresnel prisms — whatever you can, to buy time, until they’re kind of settled down. All right. I’ll go back to our discussion here. 6th nerve palsies. So when we get through 6th nerve palsies, we wanna get through 3rd nerve palsies, Botox, and adjustable sutures. So we still have a lot of fun ahead. Our next poll question has to do with Botox. Now, for a lot of us, Botox just isn’t available. But if it is available… Let me launch our poll here, so you can see it. What do you do with Botox? All right? Do you not have it available at all? You have it, but you’re not comfortable using it? You use it, but only really for things like acute 6th nerve palsies? Or you love Botox and use it for everything? You’re one of these people who uses it for infantile or non-refractive esotropia? You use it for all kinds of strabismus forms? All right. We’ll launch the results of our poll. So you can see for a lot of us just accessibility is a problem. It’s expensive. I think a vial of Botox is about $400 US. And it’s hard to use it multidose, because of the lifespan of it. Some of you aren’t comfortable using it. Hopefully we can change that today. Give you some tips. Those of you who are using it — a mixture of using it only for 6th nerve palsies, and some of you are actually using it for other forms of strabismus. All right. Let’s continue on and take a look at that. So my main use of Botox is for acute 6th nerve palsies. Just to buy time. Kind of prevent that antagonist medial rectus from contracting and becoming restricted. You do perhaps get the eye centered and get some single binocular vision straight ahead. Because most of the time with these acute 6th nerve palsies, we’re trying to see if they’re going to recover. We’re giving them a minimum of 6 months. Sometimes we’re waiting a year before we operate on these patients. And during that time, you just don’t want that medial rectus to get contracted. Now, this photograph shows it being done with an EMG needle. And I do have that available. But over the years, frankly, I’ve just stopped using this. I don’t know that it’s necessary. So don’t feel like if you don’t have this EMG machine and a connection to an EMG needle that you can’t do Botox. How does that work? Well, this EMG needle is tied into this EMG recorder, little speaker. You place that in by grafting the medial rectus and having the patient look away. But then you have them look towards the needle. And as they look towards the needle, the medial rectus, if you’re in it, the fibers get recruited, and the EMG needle picks up those recruitment, and you hear the little Geiger-counter-type speaker going off. So that’s one way to do it. And if you’re gonna do it in the office, under topical anesthesia, that’s probably the best way to do it. When I inject, I’m usually giving 5 units, but some people use less. 2.5 units. And usually the total volume that that’s in is 0.05 to 0.1 of a milliliter, up to maybe 0.15 milliliters, when you inject that. I don’t do this in the office anymore, but I do use it under anesthesia. And I’d like to show you a demonstration of that. This is a nice video, which comes up on the — this was at the Pediatric Ophthalmology Education Center, which is on the American Academy of Ophthalmology’s website. It’s about a 1-minute video.
>> Our preferred technique for the administration of botulinum toxin is to use an open approach, with a general anesthetic, as opposed to a closed approach, which necessitates the use of a ketamine anesthetic. Here a small fornix-based incision is made below the left medial rectus. A pocket is created, as shown. And the medial rectus insertion is engaged with a squint hook. A second squint hook is placed to expose the medial rectus tendon, and then 2.5 units of Botox and 0.1 mils of normal saline is slowly injected. By placing sponges, as shown, inadvertent spread of the toxin to adjacent tissues such as the levator complex is minimized, so reducing the risk of a postoperative ptosis.
DR DANIEL NEELY: So those videos — those are from the AAO’s website — those are — it’s Dr. Farris and Davies doing that. Very nice videos that you can find on there. They also have another… You need a password for the AAO’s website, but there’s another non-password-protected website that I can share with you. Let’s go back into our presentation. And again, that was an open exposure technique. You can also do that simply by grasping the medial rectus with a large-toothed forceps. And that’s what I tend to do. I do tend to do it with the patients sedated or under a brief general anesthesia. Propofol is sometimes sufficient. Simply grasp the belly of the medial rectus and inject it through the conjunctiva, and that seems to work relatively well. Also, you might have a higher incidence of spread to some of the other extraocular muscles — particularly the levator. And so that might be the advantage of an open technique, versus the closed technique. Now, what do you do with 6th nerve palsies? Well, if they’re mild, you can simply — like this one, she’s able to abduct not quite fully, but she gets up pretty far — you can simply treat them like you normally would. Do a resect/recess procedure. However, if they have a complete 6th nerve palsy and they cannot abduct past the midline, well, it really doesn’t get you much of anywhere to resect a dead lateral rectus. Therefore these people usually require the full tendon transpositions that we talked about in the previous lecture series. We talked about fundamentals, and using the rectus muscles. But simply moving the superior and the inferior rectus laterally towards that paretic lateral rectus and maybe adding this Foster augmentation suture 8 millimeters back is a nice trick, when you have a fully paretic, dead lateral rectus. I’m gonna roll into the 3rd nerve palsies, and I’ll take questions on both of those at the same time, since we have about 15 minutes left in our time together. The 3rd nerve palsies — this is not a long section. Here’s a pretty typical gentleman. He’s got ptosis, exotropia, and a hypodeviated eye. What you do for these really depends what has recovered. If it’s a partial palsy, you’ve just got to pick and choose what you still have, and you’re gonna do some combination of recess/resect. Transpositions, whatever you have. It’s the complete palsies that are really tough to deal with. If you have a complete palsy, you’ve knocked out four of the extraocular muscles. All you have left is the lateral rectus and the superior oblique. So you have a complete palsy, you’re gonna have to do something with those two. Those are really your only choices. One thing you can do is disinsert that lateral rectus. If you simply recess the lateral rectus or maybe even do a myectomy of it, take a big chunk of it out, it’s still pulling on the periorbital tissues behind the eye, and it still will pull the eye out. However, if you take that lateral rectus muscle and you suture it with a non-absorbable suture to the periosteum, when it contracts and pulls, it can’t move the eye. It’s only gonna pull against the periosteum. We don’t have time to go into a video for that, but if you go to this free website that I’m referencing here, this is the IPOSC, the International Pediatric Ophthalmology and Strabismus Council. They have resources there at IPOSC.org, and there’s a very nice video from Dr. Sharma, and it demonstrates this technique of periosteal fixation, how to expose the periosteum, and again, you’re doing that with a non-absorbable suture. What we will talk about briefly is I’ll show you this transposition of the superior oblique. Once you’ve isolated the lateral rectus, you can help hold that eye in the primary position by using the superior oblique. What we do — here you see it’s inserted normally under the superior rectus. We disinsert it, and we bring it over here and we’re going to reattach it just above the insertion of the medial rectus. Now, you’re shortening it some. We don’t show the shortening in this illustration, but once you kind of get the eye centered, and you’re laying the superior oblique across the globe and across the cornea, you can figure out about where you need to shorten it, and suture it on to keep that eye tethered in the primary position. This is an alternative to doing things like fixating the eye with a suture to the periosteum, nasally, through the medial rectus. I like to do this with the superior oblique instead. So I’ll shorten it and transpose it down here, to help hold the eye in. All right. So we do want to talk about adjustable sutures today. So we’re going to pop up and get our questions on 6th nerve palsies and 3rd nerve palsies before we move on. And our poll question is going to be… Well, let’s get back to that. Before we get into the polling, let me get you into the questions here. Back us up. There’s a question about superior rectus recession only for Duane’s retraction syndrome. I’ve not used that particular technique. I don’t have any good comments for you on single superior rectus recession. Some people — if you want to treat the enophthalmos, one way to do that, which is probably more common, is to recess both the lateral and the medial rectus, try to let that eye come forward that way. We have another question about: How do you minimize late overcorrection after inferior rectus recession and thyroid ophthalmopathy? Well, I think the way that you minimize the late overcorrections has to do with possibly using the non-absorbable suture. I think that’s the rationale for that. Using the 5-0 suture of braided polyester, something like Mersilene. And that will help you to prevent slippage of that muscle later on. All right. So adjustable sutures. This is always a bit of an interesting topic, and one that people are very passionate about, for or against. I’ll let you know right ahead that I have done adjustables, and I do them very rarely at this point in time. I don’t find personally that I use them a lot. But let’s see what all of you do. So our final poll question. Do you do adjustables? Yes or no? Pretty straightforward. And I don’t think there’s a right or wrong answer here. I certainly think there are a select group of patients where adjustables can be very helpful. I don’t think you have to do adjustables to have good results. And sometimes doing an adjustable might actually lead to a worse result. Who knows? We all have passionate opinions about this. And we all come to a decision that’s right or wrong for us. And it depends on numerous things. But… Looks like some of us, maybe about a 1/3, do adjustables, and the other 2/3 don’t. And I kind of see this in the States. I see pockets of people doing adjustables and pockets where people don’t do adjustables. It really just depends on what your comfort level is with doing them. Whether or not you think you need them, whether you’re unhappy with your results. Frankly, there’s never been a study that compares the results of adjustables versus non-adjustables, so we end up dealing with a lot of opinions and anecdotal evidence. But I think it’s good to know how to do these. Because they do have a role in strabismus surgery. There are times when we want to be able to adjust a muscle. The two basic techniques are the bow tie technique, so the muscle is fixated, passes through the insertion, and then maybe put one throw through here. But then instead of putting a second throw on there, you’re tying a bow tie, so it’s tied into a loop, so you can pull one of these and loosen it and let that muscle slide back. The other common technique is the sliding noose technique, and we’re going to look at a video of this one. I’m not sure which of these is probably more common. This is probably more technically interesting. And that’s why we’ll look at this video. But here you have a loop that’s tied around the suture, and this sliding noose can be slid forward and backward, to allow this muscle to position forward and backward. So let’s take a peek at that. All right. Before we get to the video, if you want to read about this, I think this is a very nice chapter in Pediatric Ophthalmology, Current Though and a Practical Guide. Dr. Hunter, who’s a big proponent of adjustable sutures, has a very nice chapter in there. You can see it’s about 13 pages long. It’s a nice resource. Again, at the AAO’s website, on the ONE network, Pediatric Ophthalmology Education Center, they have a very nice video here. And the same people that we saw the video before, of the Botox injection, Dr. Farris and Dr. Davies — let’s take a look at this. This is a sliding noose technique.
>> This is an example of the sliding noose adjustable suture technique, demonstrated on a model eye. The lateral rectus in this case has been secured with our standard continuous 6-0 vicryl suture, and scleral pass is made at the outer borders of the lateral rectus, emerging 1 to 2 millimeters apart in the sclera between the original insertion and the limbus. Both sutures are cut at between 8 and 9 centimeters. And then these pole sutures are tied with a double and then a single throw, over a pair of Moorfields forceps. A separate piece of 6-0 vicryl is cut, and this will form the sliding noose suture. A single throw is tied as shown. The pole sutures are moved laterally, and then two further single throws are created on the opposite side of the pole sutures. A bucket handle is then created by grasping the noose sutures 2 centimeters from the sliding knot, and then tying a double and a single throw. The ends of these sutures can then be trimmed as shown. The lateral rectus is then advanced to its original insertion. Calipers are set at 7 millimeters. And the sliding noose is advanced to the 7-millimeter point, as shown. Once the lateral rectus has moved posteriorly, we check that a 7-millimeter recession has been achieved. To advance the lateral rectus postoperatively, traction is placed on the pole sutures, and then the sliding noose is moved backwards, to secure the muscle in its new position. Once a satisfactory alignment has been achieved, the pole sutures are tied off with a double and two single throws. These sutures are then cut 2 millimeters from this knot. The noose sutures can now be cut 1 millimeter from their original knot. And the conjunctiva closed.
DR DANIEL NEELY: So I think that’s a really great teaching video. The authors of those videos, while they’re being hosted on the Pediatric Ophthalmology Education Center — again, that’s the American Academy of Ophthalmology’s ONE, or ONE Network. That’s where that particular video came from. But if you don’t have access to that, the authors also have those same videos and many others on different ophthalmic surgical techniques at this website, simulatedocularsurgery.com. And if you go there, they have a lot of demonstrations on those model eyes like that. I think it’s really a great demonstration. These are perhaps some of the best demonstrations of surgical techniques, and particularly adjustable sutures, that I have found. Now, another great resource, of course — slightly biased — is Orbis Cybersight. Not only does Orbis have free books — you can get entire books online that you can view online or download at Orbis Cybersight. We have Dr. Von Noorden’s Binocular Vision and Ocular Motility. The entire text. We have Strabismus: A Decision-Making Approach, translated into English and Chinese. Again, the entire text is available. And then finally, Surgical Management of Strabismus, by Dr. Helveston. This is a nice one, one of my favorites, because it’s very case-based. They’ll give you a case study like we looked at with our bilateral superior oblique palsy, walk you through the findings, and then talk to you about how to treat that. And so these are all available online for free, or as a PDF download. Now, Orbis Cybersight is a great resource that we want all of you to utilize also. Obviously we can’t get to every problem and talk about it in depth. But all you need to do is go to cybersight.org, and if you come down here, you have the library resources to all the videos and books. If you go here to the consult section, you have at your disposal expert consultation for strabismus or any other subspecialty in ophthalmology, 24 hours a day, 7 days a week. And you just log in, and I’m gonna show you what a sample case looks like. And your case will go to an international expert that will answer your question. And there’s no dumb question. We all know that we all need to be able to ask questions. Here’s the case that’s been submitted from Cambodia. My good friend Dr. Kav. And this is a case of V pattern bilateral inferior oblique overaction. Here you can see the inferior obliques are overacting. A little underaction of the superior obliques. So a lot like that bilateral 4th nerve palsy case we saw. Here’s the V pattern. 35XT, 16XT. Pretty straight in downgaze. And then look at this. We have all the photos. And you can see the left inferior oblique overaction, the right inferior oblique overaction. Downgaze. Primary. Head tilt. And, now, Dr. Kav’s done a great job of all this lovely information. You don’t have to enter all of this. Enter whatever you have. Even if you don’t have photographs, people can usually answer your consult. Once you enter your diagnosis, that goes off to a mentor, and here you can see that after that was sent to me, Dr. Kav and I had a relatively long discussion back and forth about what to do with this patient. And not only that — we then went on and he took some surgical photos and postoperative photos, and we had an ongoing discussion even after surgery. And we can even do things like — here’s a little diagram I drew, demonstrating something I like to do sometimes, which is a pseudoanterior transposition inferior oblique. So many, many tools at your disposal. And I would urge all of you to take advantage of that free service from Cybersight, and the consultation service. We have a last few questions before we wrap things up. And I have a question here — what if there’s residual exotropia of 30 prism diopters after a lateral rectus disinsertion and a medial rectus resection has been done? So the lateral rectus is disinserted, and the medial rectus has been resected. And you can see this kind of demonstrates my point about not just recessing or extirpating the lateral rectus. Because it’s still going to pull. So if you have a lateral rectus, suture to the periosteum, and then in this particular case, since they’ve already recessed it, and disinserted it, they can either go back and try and find it, hook it to the periosteum, or they can go ahead and do that superior oblique transposition, and that would be another way to take care of that. All right. Looks like we’ve covered everyone’s questions. So, again, I appreciate everyone’s patience today at the beginning. Sorry about the technical SNAFU. Thank you for your time, and I hope you’ll continue to join us with our webinar series. We do have an upcoming one, which will be on pediatric glaucoma. And subsequent to that, expecting to get into some other topics. We want to start covering other subspecialties, and have an ongoing teaching session with all of us. So thank you again for your time, and please join us again. Thank you.