Surgery: Lateral Rectus Resection in Residual Esotropia

This 2-year-old child had a history infantile esotropia and a bilateral medial rectus recession was done previously. Dr. Fredrick decided to do a strengthening procedure of the lateral rectus as the eyes were still esotropic. This video demonstrates a lateral rectus resection surgery in the left eye of this child. All the steps of the surgery are demonstrated and explained beautifully by Dr. Fredrick in this video.

Surgery Location: on-board the Orbis Flying Eye Hospital in Addis Ababa, Ethiopia
Surgeon: Dr. Douglas Fredrick, Mount Sinai School of Medicine, USA

Transcript

DR FREDRICK: This is a 2.5-year-old boy with a history of infantile esotropia. So the eye is turned in within the first few months of life. He already had one surgical procedure. He had a bilateral medial rectus recession. You can see by looking at the medial area some scarring from the previous surgery. So he had a bimedial recession. 5.5 on both sides, the right and the left, but the eyes are still esotropic. And when we checked the measurements in the clinic, the measurements are 35 prism diopters in all fields of gaze. So there’s no A pattern and there’s no V pattern. So whether looking up, down, left, or right, the deviation was 35 prism diopters. So since the medial rectus has already been done, we’re going to do a strengthening procedure of the lateral rectus muscle on each eye. So we’ll do a lateral rectus resection of 6.5 millimeters on each side. And we’re going to do forced duction testing now. So what I’m going to do is I’m going to see if there’s resistance to the eye going out or resistance to the eye going in. First I’m gonna check to see if there’s resistance to the eye going out. Now, remember, this is a child whose eyes are turned in, normally. The eyes are 35, esotropic. So I’m interested in seeing if the medial rectus muscle is tight. So I grab the limbus with a 0.5 pickup. You don’t use a 0.12. That will tear the conjunctiva. I’m careful not to push the eye down. I don’t push the eye down in the socket, because that will give you a false negative exam. See? It’s easy for me to push the eye over. So I lift the eye up, and now I push the eye over. Now, you see here: It’s easy for me to get the limbus to the canthus. So there’s no restriction of the medial rectus muscle. So that means the previous surgery did a good job relaxing this inner muscle. There’s no scar tissue on the inner muscle, the medial rectus. In likewise fashion, I lift up the lateral limbus, and I push over, and I see there’s no restriction. So this is something that you should do on every strabismus case, so you get to understand what normal feels like. I’m also gonna check up and I’m going to check down. What I’m doing now is I’m gonna put a traction suture. And this is a nice technique if you don’t have a surgical scrub who can help you with the assistance. So I’m grasping the limbus, and I’m grasping not right at the limbus. I’m grasping at the insertion of Tenon’s. Now, this is 5-0 silk on a tapered needle. It’s not a spatulated needle. It’s not a cutting needle. And you see a nice tapered needle will not penetrate the eye, and it doesn’t cause any bleeding. So it’s an excellent suture if you have it. The needle is called a taper needle. It might be listed as a B-B. Now, needles always have names. Cutting needles are called P needles. Ophthalmic needles are called S needles. And they all have a reason why they’re called B-B or P or S. So we’re gonna use a limbal incision. And the way we do this is: We know the lateral rectus muscle is here. You can see the lateral rectus muscle underneath the sclera. See how it’s a little bit pink? We know that’s where the muscle is going to be. I’m going to grasp the conjunctiva and lift it up, like lifting up a sheet, and I’m gonna cut there. And then I’m gonna go in the inferior temporal quadrant, grasp the tissue, and cut here. So you see I have two cuts. Two radial cuts here and here. And then I’m just gonna lift and I’m gonna spread the tissue underneath. So I’m underneath Tenon’s capsule. I put the blade in, and I cut flush. And you can see that leaves me with two nice sharp corners that I can use to put this back after we’re done. And you have relaxing incisions that are big enough, so you don’t need to relax it anymore. So that’s your conjunctival incision. Next we’re going to expose the sclera above and below the muscle. Normally when you see a retina surgeon or a glaucoma surgeon or any other surgeon clean Tenon’s, they put the scissors in like this and they open like that. We don’t want to do that for muscles, because the scissor will bump into the muscle and make it bleed. We want to hold the scissor vertically. And all we want to do is punch a little hole through the Tenon’s, so we can see sclera. So you see I’m lifting up. I’m above the muscle. It’s nice and shiny white. That’s bare sclera. I mow the muscle’s gonna be right underneath that. In the same fashion, I go underneath, until I see nice shiny white sclera. Now, I have a good view here. So I’m not gonna let go. I’m gonna hold the conjunctiva and the Tenon’s, and I have a nice hole right there. So now I’m gonna use a Graefe muscle hook. The Graefe is an L shape. It’s smooth. There’s no bump on the end. The first muscle hook you want to use is smooth, so it doesn’t get caught on any Tenon’s. Put the toe down against the shiny white sclera and slide it underneath the muscle. And then it comes up on the other side. Where you made your first hole. And you see? Nice and shiny. So you don’t have any tissue adherent. Then you take a Green hook. You can see it’s similar, but it’s got a little notch on the end. This is what we use to keep the hook from falling off the muscle. So what I do is I go through the toe to the heel of the first muscle hook, and it comes up nice and shiny and clear, so I don’t have any tissue adherent to that. So I have the lateral rectus muscle. I’m gonna have the assistant use his right hand and hold the muscle for me, so I can get good exposure. So now I’m gonna take the scissors, the Westcott scissors, and I’m gonna lift the conjunctiva and Tenon’s, and you see this little band of tissue. This is the intramuscular septum. I make a little cut. And then I spread. So I’m spreading on top of the muscle. A little cut and spread. Until I see the nice pink muscle there. Once I have that exposed, I can use a retractor. So I’m gonna use a Desmarres retractor. What we want to do now is clean off the edge of the muscle. So I can see the edge of the muscle right there. And this is the intramuscular septum and Tenon’s. So the way you clean off the muscle is you take your 0.5, you grab this filmy tissue, and then I’m going to slide the scissors down this way. Like when you’re using scissors to cut wrapping paper, when you’re making a present. You see, I’m not doing much cutting. I’m just sliding along the edge. And here I have a nice clean edge of muscle. Now, I’m gonna do a resection. So I want to make sure that I have at least 6.5 millimeters, because that’s how much resection I’m going to do. Then I move the eye up like this. And in a likewise fashion, I grab the tissue here, and I cut right along the edge. Now, when you’re doing the lateral rectus muscle, I don’t want to go too far back too quickly, because I’ll bump into something important. What will I bump into, if I just take these scissors and make a big cut like that? What could I run into that I don’t want to run into? The inferior oblique. So I want to make sure not to cut too aggressively, too rapidly. I want to make sure that I have good exposure, so that I have good nice clean lateral rectus muscle here. So now I’m gonna take a second muscle hook. I’ll take a Jameson hook. I’m gonna put this second hook in, and the retractor comes out. Now I’m going to spread the muscle part. And we’ve determined how much surgery we’re gonna do, based on the measurement. So for a 35 esotropia, we’re going to do a 6.5 millimeter resection. We’re going to strengthen this muscle. So we’re gonna measure. So you can sometimes make a little mark with a marking pen, or you can make a burn with a cautery. In my case, I’m just looking — I see a little end of a vessel right there. That’s the mark I want to use. So I’m going to now take a double-armed 6-0 vicryl suture, and it’s an S29 needle. I’m taking a central bite. So that’s a full thickness bite. And I’m gonna tie this. Now, this suture is a long suture. Sometimes you would do instrument ties, but in this case, with a long suture, I find that doing a hand tie gives me more control. So I just do two single throws to secure the suture. Because this way you’ll see: I’m gonna have three-point fixation on the muscle. Now I’m gonna have my caliper again, and I’m going to confirm that it’s 6.5 millimeters. So it’s just where I want it to be. So I’m in the proper location. So now I’m gonna take, again, one of the ends of the suture with this S29. You can see I’m taking this needle. I’m holding it flat against the muscle. And I’m weaving it up and down. See, I’m going up and down like a submarine gliding through the sea. And it’s on average 50% through the thickness of the muscle. It’s not all the way through. You can tell that because the way the needle is sitting here. If this was all the way through the muscle, the point of the needle would be going backwards towards the sclera. But it’s sitting here like this. So that tells you that it’s half thickness. So I pull that through. So now the first pass was half thickness. The second half is going to be full thickness. So I go from front to back, and I’m taking about a quarter of the thickness of the muscle. And this one I want to be locked. And so this is a locking bite. So we’re doing the same thing. Going out to the side. And then we’ll do our locking bite again. So now we have the muscle firmly secured in three places. One in the middle and then two each on the sides. We’re gonna take that straight hemostat — or it could be a curved hemostat — and we’re gonna crush the muscle anterior to the suture placement. Now, you see, I don’t get too close to the stitch. If you get too close to the stitch, the crushed muscle will slip through the suture. And you don’t want that. And I’m gonna cut in the middle of that crush. So that I have plenty of meat, plenty of muscle, on the suture. Now I’m gonna take my pickup, and I’m gonna take the scissor, and I’m gonna remove most of the stump. Not all of it. I’m gonna leave about a millimeter of tissue to grab onto, when I reimplant. I’m gonna do some cautery. Each muscle has ciliary vessels. These are vessels that supply blood flow to the front of the eye.

>> Right. And that’s why we don’t want to have cut too many muscles on a single eye, because you can get ischemic syndromes, correct?

DR FREDRICK: Right. You can get anterior segment ischemia. So generally we limit it to two rectus muscles at a time per eye. The oblique muscles do not supply ciliary vessels to the front part of the eye. So we’re going to reimplant this now. And so I want to point out a couple things. First off, you can see: This is the insertion. And it’s dark here. Why is it dark here? Is that a nevus? Does it make me happy that it’s dark there?

>> The question is: Is it thin sclera? So that it’s dark simply because there’s not a lot of white overlying it?

DR FREDRICK: That’s right. So it’s very thin. It ruptures when you have blunt trauma behind the rectus muscle or it’ll rupture at the limbus. Those are the two weak spots. So because I don’t want to put the stitch, the needle, through this thin sclera, I’m gonna put it where it’s safe. I’m gonna put it in front of that thin sclera. So that’s the old insertion of the lateral rectus muscle. What I’m gonna do is: I grab that with my sutures, and this is where the needle first goes. But you can see: I’m observing where the needle is at all times. Now, you see, first off, how I’m holding the needle. I’m not going like this, like a bird diving towards the sea to get a fish. I hold it flat here. So that if I accidentally let go of the muscle, the needle is not gonna penetrate the eye. So I grab this, and I hold the back part of the needle very flat. I engage the sclera. And I can see the grey needle in the sclera at all times. You can see the tip’s gonna emerge right there. You can see how it’s grey. So that’s done in safe, firm sclera. And then I’m gonna take my other needle from the other half of the muscle, and I’m gonna grab the superior pole. And here you see I’m not engaging sclera. I’m just putting it through the little stump, until I see the needle tip emerge on the other side. See the needle tip? Then I know I’m safe. I see the needle tip there, and I can engage sclera. And again, I’m following the grey needle. So they’re coming like a V towards each other. They don’t have to emerge right next to each other. They just have to be close. So I have the muscle at the superior old insertion. The inferior old insertion. Always good to keep visibility. Because if you cannot see the needle, you could be in the suprachoroidal space. You could be full thickness. The episclera is very firm, and you don’t really need very deep bites. So if you have to make an error, it’s better to err too shallow. And you would be surprised how firm the scleral tissue is. I’m shooting for about 30% depth. Because again, what is the thickness of the sclera here? How many millimeters? 0.8 might be right up here. It might be 0.5 here. Behind the insertion, it’s about 0.3. So you don’t have a lot of room. So now this is a triple throw. One, two, three. So I grab here. Now, this is an important part. You see how I want the knot to be nice and spread apart? I don’t have it all bunched up. So I’ll take another needle holder, an empty needle holder, and again, I’m grasping close to the knot. Close to the knot here. You see how the knot is nice and spread evenly. So it’s not lumped up. I’m gonna pull this direction. I don’t want to pull up, because I don’t want to put pressure on the sclera. I go in this direction. Pull down. And then cinching up. Now, sometimes what you can do, if you have a nice assistant, the assistant can grab a 0.5, and they can grasp the middle of the old insertion here. And what they’ll do is: I pull towards me. He pulls towards him. And that allows the muscle to come up, without putting extra tension on the muscle. It’s a nice technique. And now you can see: There’s the muscle insertion. Nice and tucked in. Tucked in nicely against the old insertion. So, you see, there’s no sagging of the muscle. That’s why we use 3-point fixation. So it’s nice and spread evenly across. Now, it’s important when you’ve done a good job bringing the muscle forward — you don’t want to yank on this knot, because the muscle can slide back. So, you see, I haven’t put any tension on this. Then I lock it down with a locking. Once I’ve done this, I can do anything. The muscle’s not gonna slip. The muscle is nice and firmly secured. So then I add two more single throws. So that’s a 3-1-1-1. And that way, it won’t slip. So I have four knots. And you always leave a little tag. You don’t cut this short. You leave a little bit of a tag. It’s simple, because we took our time and did a nice peritomy. We’re going to put the corners back together. You can use lots of different material. I like to use a 6-0 plain gut suture. You can also use the 6-0 vicryl that you use for the muscle. The 6-0 vicryl will last for six weeks, so it will bother the patient. If you use a 6-0 vicryl suture to close the conjunctiva, you have to bury the knots. Now, it’s also important to get a pretty outcome: You want to make sure you’re getting just conjunctiva, not sclera. So I put it right through the corner here, I lift up, and I put it through the corner there. And for the corners, I also like to do a 2-1-1. The amount of resection is from where the muscle gets reinserted. It’s not from where it’s cut. Because you can actually do another strengthening procedure called a plication, where you don’t cut the muscle at all. You put the suture in just like I did, but then you just reimplant it back in the old insertion, so you cause a knuckle, a loop of muscle to come forward. And it has the same effect as resection. So what’s important is where the muscle gets reimplanted. Not exactly where it’s cut. So when you’re doing a closure, it’s important to make sure you’re closing conjunctiva. In the healing phase, since you’re using an absorbable suture, you’re gonna get an inflammatory response. It would look like a pink granuloma. It’s not an infection, because there’s no discharge, but it’s very irritated, raised, and elevated. And usually that responds well to topical steroids. So that’s a pyogenic granuloma.

>> And what would happen if you reapproximated those two tissues that are not the same plane? What would you get?

DR FREDRICK: So here is my conjunctiva here. So I want to make sure I get just conjunctival tissue, not Tenon’s tissue. So now I have conjunctiva to conjunctiva. Because if I don’t do that, I can get another complication, which is an inclusion cyst. A Tenon’s inclusion cyst, or an epithelial cyst. Both of which are ugly to the patient. They might have straight eyes, but they’ll be very mad at you, because it looks bad. The other complication, especially when you’re doing a medial rectus recession, if you’re not careful in reapproximating the conjunctiva, you can accidentally pull the plica or the semilunaris forward, and get a band of pink tissue that’s growing where it shouldn’t grow. So instead of having a white bulbar conjunctiva, you can have the plica pulled down where it doesn’t belong, closer to the limbus. So you just have to be careful and pay close attention to your insertion. At the end of the case, we’re gonna inject some lidocaine and bupivacaine right underneath the muscle. That allows the child to have less pain when they wake up, and it allows anesthesia to not require them to use as much narcotic when they’re waking the child up, so the child can go home quicker, and so they don’t throw up. They don’t vomit.

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October 13, 2018

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