The SOS Advanced Trabeculectomy eye is being used to demonstrate how to close the conjunctiva after a trabeculectomy surgery. Simultaneous live and simulated surgical footage demonstrates how realistic this simulation is.
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 video, Andy McNaught describes his preferred method for conjunctival closure at the end of a trabeculectomy procedure, using footage from simulated ocular surgery eyes and from live surgery.
>> 10-0 nylon is used to suture the conjunctiva. This is because nylon is inert and less likely to induce fibrosis of the bleb. I’ve passed the needle from the inside of the wound through the cornea, then out, and then repassed the suture from the outside into the wound. This is to ensure that the knot ends up deep to the surface of the conjunctiva, and does not irritate the patient. With the simulated surgery eye, the conjunctiva has a little more elastic recoil than natural conjunctiva. So I use a 3-1-1 suturing knot formation technique to overcome this. I pull the suture very tight. And then I cut the suture ends very short, because it’s most important there’s no nylon suture ends protruding, which will attract mucus. And be uncomfortable for the patient. Again, passing the nylon from the inside of the wound through the cornea, picking up some corneal collagen fibers to anchor the suture at the limbus, and then passing the nylon suture back from the outside, and then emerging from the wound to ensure the knot is buried. Use three turns. 3-1-1. The suture is pulled tight, laying the knot correctly. And this pulls the conjunctival wound under great tension. To ensure that the wound is watertight. Just putting the locking turn on. And again, cutting the suture very short, so there’s no protruding nylon suture ends to irritate the patient. Finally, the last suture is a horizontal mattress suture. This is passed through the peripheral cornea, parallel with the limbus, which is a relatively short path, and then it’s passed through the conjunctival flap, with a relatively long pass. And consequently, when the suture is tied tight, the conjunctiva is brought together to increase the tension across the front of the wound, and reduce the risk of aqueous leakage from the front of this wound. So very tight. In the manner of a drawstring suture. To ensure a watertight fornix-based flap wound. 3-1-1. To form the knot. This suture is of course buried by the conjunctival flap, but again, it’s cut very short. And finally, some surgeons will then turn that knot in to the cornea, to be doubly sure that it’s not going to irritate the patient. The anterior chamber is reformed with BSS, as a final check that the releasable suture is sufficiently tight, to ensure against hypotony, so the pressure is high. The sutures are tight. The valve is not draining. And finally, an injection of some subconjunctival antibiotic and steroid.