Surgery: Postoperative Needling for a Fibrosed XEN® Gel Stent

This video describes postoperative needling procedure for a fibrosed XEN® Gel Stent in a fairly flat bleb.

Surgeon: Dr. Ike K. Ahmed, University of Toronto, Canada



This video describes postoperative needling for a fibrosed Xen with a fairly flat bleb. Mitomycin 0.5 milligrams per CC has already been injected just posterior to the bleb, prior to needling. 27-gauge needle is used to pass under the subconj space, about 2, 3 clock hours away from the Xen implant here. Which you can see is in the superonasal quadrant. What we first visualized here is the Xen implant here — you can see it under the conjunctiva — the needle bevel is placed under the implant carefully, and slid under the implant, while then the needle is then swept toward the fornix. The slide and sweep technique is used to cut fibrotic tissue around the implant. There’s the implant. You can see the needle bevel is under it, and now we basically sweep toward the fornix. This is a fairly vigorous maneuver, to ensure that we have cut fibrotic tissue around the implant. This is done numerous times, sweeping widely. Trying to get under the implant preferentially here, to ensure we then release the typical fibrotic web or scar tissue overlying the implant. The goal here of course is to then ensure adequate flow emerging from the implant in the subconj space. We actually see already we do see some elevation of conjunctiva with some fluid percolation now in the subconj space, accompanied with a reduction in IOP immediately after the needling is already occurring. The needle is also attempted to be placed above the implant, just under the conjunctiva, to, again, release any fibrotic tissue overlying the implant as well. And it’s the underpass/overpass, so to speak, sliding the needle above and under the implant, while sweeping toward the fornix here, allows for, then, freedom of the implant. The implant actually is more free now, and it moves as well. You can really see a nice bleb forming here, with this technique. This is done at the slit lamp here. I prefer not to use a speculum. And we actually have a Q-Tip in our hand to hold the lid away, as well as to palpate the eye periodically. This continues to occur, widening the subconj space distal to the implant, which really ensures we have a nice, well formed posterior bleb. The use of viscoelastic may be injected at this point, to further separate tissue and retain a bleb for the first few days. Typically cohesive viscoelastic can be used to do this. And this, along with the use of an antifibrotic, can be helpful to ensure we have good wound healing control. Typically postoperative topical steroids are used as well, vigorously for the first few weeks as well, to control inflammation. At the end of the needling, the pressure drops typically into single digits. And the bleb is nicely well formed.

October 31, 2019

Last Updated: October 31, 2022

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