Simulated Surgery: Strabismus Surgery: Bow-knot Adjustable Suture Technique

The SOS Basic Strabismus eye is being used to illustrate the creation of a bow-knot adjustable suture on a lateral rectus and demonstrate how it can be released and the muscle then advanced or further recessed.

In addition to Cybersight, you can find videos featuring teaching techniques for all types of ocular surgery, using any form of simulation, in the Simulation Gallery.


>> In this clip, we’re going to illustrate a lateral rectus recession, using an adjustable suture technique. Again, there are many different techniques. Here, we’re going to use a bowknot technique, as opposed to the sliding noose technique. And one of the things that the eyes are extremely useful for is allowing the trainee to practice making relatively long scleral passes with confidence. With adjustable squint surgery, I like to ensure the muscle is as well spread as possible, and by creating these long passes, it enables me to do this. Some people use a crossed swords technique. Having placed the sutures, I’m just advancing the muscle up towards the equator. Then we’ll cut the stitches and fashion that bowknot. Again, I would emphasize: It doesn’t matter which technique you’re using, as long as the trainee receives appropriate instruction before practicing it by themselves. So a double throw at this point. And then advancing the muscle to the desired recessed position. And then creating a little bowknot. Like so. I tend to cut this suture short. This will be the one that I pull to release the knot. And the other one, slightly longer. Now to practice advancing the muscle. Just pull on the shortened suture. We teach the trainee to hold the sutures close to the original knot, so we get a degree of purchase on it. You can see there’s a reasonable degree of resistance to advancing the muscle, as it would do in real life. This is because the elastic band underneath the cap is making it slightly difficult to move the muscle forward. And we’ve just retied the knot. I’m going to illustrate here how the lateral rectus can be recessed further. Again, undoing the bowknot. Then advancing the suture slightly off the sclera, so the St. Martin’s forceps can be placed underneath the suture, and that knot opened up. It’s harder to grip the basic eye than it is the advanced eye. And certainly more difficult than it is in real life. We’re getting the patient, if you like, to look to their left, abduct the eye by pulling on the lateral rectus, and securing the globe with the right hand. The muscle is recessed further. The double throw is again secured. And orientating the suture correctly. And the bowknot retied.

Last Updated: October 31, 2022

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