This video demonstrates Baerveldt Glaucoma Implant surgery in a patient who has had a history of failed trabeculectomy.
Surgeon: Dr. Ike K. Ahmed, University of Toronto, Canada
This video demonstrates the Baerveldt glaucoma implant surgical technique. This patient has had a history of failed mitomycin trabeculectomy, and under topical anesthesia, the surgery started by placing a 7-0 vicryl on a TG140 needle through the superior cornea, typically supranasal, to create a bridle suture for corneal traction. Corneal protection is maintained with Cornea Protect and corneal light shield, and the eye basically is then moved into the inferonasal position here, exposing the supratemporal quadrant. The conjunctiva then is incised to create a 1-quadrant peritomy. This is started with a radial incision here, initially laterally here, to coincide near the lateral rectus insertion. A pair of blunt Westcott scissors is used, along with a ring forceps, to elevate the conjunctival flap, also injecting some subconjunctival lidocaine as well for analgesia. The radial incision is made essentially over the lateral rectus muscle. And the peritomy is cut flush to the limbus here, raising this conjunctival flap. Once we get just past the 12:00 position here, we have to get past the 12:00 position, this will be near the entry for the tube into the eye. We will then make a radial incision again along the axis of the superior rectus muscle here, and as we see here, as we cut the intramuscular membrane here, as well as dissecting bluntly here, in the inferotemporal conj, as we’ll see later, for the ripcord suture. We then expose the superior rectus muscle here, again, cutting the conjunctiva further to expose that muscle. Exposure is important here. And then we use a combination of blunt and sharp dissection here, essentially to cut some of that intramuscular septum. That membrane here that basically will help to expose the lateral aspect of the superior rectus muscle. The muscle hook is used and handed off to an assistant, to essentially expose the rest of the muscle, and we can see how the conjunctiva is further cut to expose the posterior aspect of that muscle as well. As we’ll need to place the implant under the superior rectus muscle. The lateral rectus muscle exposed here again, using blunt dissection again, and sharp dissection to cut some of the intramuscular membrane here. We can see the superior aspect of the lateral rectus muscle, which is important to expose. Again, the muscle is used for the exposure. Pulling the eye over nasally here, to again expose and bluntly dissect into the superotemporal quadrant, to provide enough space here for the Baerveldt implant, as we’ll see shortly. Further lidocaine can be injected here again for analgesia, and light cautery is used if necessary for hemostasis. The Baerveldt is brought to the field, and in this case, a 4-0 nylon suture is used for ripcord. Just placed a few millimeters past the tube-plate junction. 0.3 forceps is used just past the midline of the Baerveldt, to hold the implant along the long axis, and here again, we use a muscle hook held by an assistant. Second muscle hook held by the surgeon. To lift the muscle superiorly here. Placing the Baerveldt here. As you can see, the majority of the Baerveldt goes under the superior rectus muscle here, allowing us to then basically dip the temporal tail under the lateral rectus muscle, as you’ll see here again, using the muscle hook to expose that lateral rectus muscle here. Elevating the muscle and placing the implant. So both wings are under the rectus muscles here. At this point, we have prepared a 6-0 prolene suture here. This suture will be used to secure the plate to the sclera. The suture passes are used typically — approximately 9 to 10 millimeters posterior to the limbus, to center the implant between both rectus muscles here. Superficial pass is made. Partial thickness through the sclera. Approximately 1 millimeter in length. Not too long. Again, the second eyelet is also — suture is placed in the second eyelet here again, with the same needle, and basically this will help to secure the implant here, pacing the needle through the eyelet. A 3-1-1 knot is used, and it’s important to secure this knot tightly. We want to ensure this implant is fixed securely to avoid any micromovements. And once we cinch the knot, we can then basically lock the knot with additional throws. We will then trim the suture, and it’s important to trim that suture fairly short, and these knots, as we’ll see, will be rotated into those fixation holes. Note, again, how the implant is secured nicely between both rectus muscles, with both wings under the rectus muscles here. And you can see the ripcord suture here still has not been tucked under the conjunctiva yet, but is placed within the lumen of the tube. We see now once these prolene sutures are trimmed, the knots are rotated into the fixation eyelets here, to prevent exposure and erosion of the knots through conjunctiva. And again, just simply using a needle driver to rotate the knots posteriorly, and then using one jaw of the needle driver to place it into the holes helps. We’ll mobilize the conj flap to make sure that has not been trapped behind the implant. At this point, we can release the traction suture. We’ll basically pull that 4-0 nylon ripcord all the way back to basically only having approximately 3 or so millimeters in the tube. And that portion will be the part of the tube that we’ll ligate. You can notice I’m just planning where we’re gonna place the graft. You can see the exposure of the tube here, beyond the ripcord. The ripcord sutures that are placed in the inferotemporal quadrant have been bluntly dissected, and it’s important to place that away from the limbus. We’ll then use a 7-0 vicryl suture again, as our ligature. This will be tied securely and tightly around the tube, in the vicinity of the 4-0 ripcord suture, which helps to create a watertight seal. This knot will be placed, as you can see, with the knot on the undersurface of the tube. This will allow potential laser, if necessary, to be done on the suture, on the superficial side, more easily. The knot is then secured tightly, as you can see, around the tube, in the vicinity of the ripcord, and that’s why we want to have the ripcord exposed about 3 millimeters into the tube. Allowing this ligature to be placed around it. This will create a watertight seal, and again, very important to tie this securely. We like to see under high magnification the indentation of the tube around the 4-0 ripcord, which will then be locked here with this vicryl suture here, to secure the knot. Once we’ve done this, we will verify the seal here, by injecting some BSS into the distal end of that tube. As we see here, there’s no flow into the plate here. Which confirms the watertightness of the ligature. Note again the ripcord present here, which is placed under the subconj. Inferotemporal. The incision is made here to provide access to the anterior chamber, prior to entry. And then the tube is placed in an area — in a location where we intend on implanting the tube. You can see that we placed it a bit — pointing toward the nasal quadrant, so it enters the sclera obliquely, and typically near 12:00, to provide adequate lid coverage. The needle track entrance is made at the scleral spur, at the level of the iris plane, and again directing it toward nasal quadrant, to provide a more oblique entrance into the anterior chamber. Typically, a 22 or 23-gauge needle is used, and the external orifice is slightly enlarged to ease the insertion of the tube, which is used here with a curve higher, placed into the anterior chamber. The tube should enter just anterior to the iris, and placed parallel to the iris, as you can see adequately in this view. So BSS is injected into the AC, to ensure we have adequate pressurization, and here we’ll use a small 3×3 millimeter scleral graft to be placed over the anterior aspect of the tube. We will secure this graft here with two 7-0 vicryl sutures again, that will be used to secure and cover the tube at the anterior aspect. Our feeling is that essentially the tube needs to be covered anteriorly. There’s no need to cover the tube farther back. This will be important as well, because we will make two fenestrations, which we want to make sure are patent and functioning, and therefore not covered by the graft. Here’s the second pass made of the vicryl suture. Note that we have not locked the sutures yet. We may want to adjust the tension. It’s important not to tie these excessively tight, to prevent torquing of the tube anteriorly. These are just placed fairly loosely but snug. And once we have adequate positioning of that graft, we will then lock both suture knots here again. Typically two are placed along the anterior aspect of that graft. Occasionally we will place a third or fourth on the posterior aspect, if necessary. Two fenestration are made. Typically two or three here. Again, between the end of the 4-0 nylon and the back of the scleral graft. And you can see we enlarge them slightly, moving the needle tip of the TG140 needle back and forth, to ensure we have an adequate sized fenestration that’s made. Typically two, sometimes three of these fenestrations are made, and again, we can see how they’re being placed between the ligature, the ripcord, and the scleral graft. BSS is injected. We can see some nice flow that emanates from the tube here, that we hope will maintain adequate pressure control for the first few weeks prior to the ligature opening up. Typically at six weeks post-op. The conjunctiva and Tenon’s is brought forward, and will be then used to close the area of the peritomy. Again, mobilizing the conjunctival flap to ensure adequate coverage. It’s important that that flap covers the anterior aspect of the graft. Two wing sutures are used in either corner. Again, back to our 7-0 vicryl here. To secure the conj flap. A bite of episcleral is used as well, to anchor those suture knots. And you can see the superior aspect is being sutured here first. We will then proceed to place an additional suture to close here. This is basically conj to conj, to close that radial incision. Usually one suture or a horizontal mattress suture is used to close that radial incision. And then we’ll do the same here. Just pointing out here that ripcord, which you can see under the conj, which can be removed later on. A few months, typically, post-op, if needed. Or maybe maintain the position. Here we can see the wing suture being used to close the conjunctiva again, and again, we have adequate coverage, and the peritomy is nice and taut over the limbus here. The radial incision is basically closed here again, with a simple interrupted here. We’re not trying to get a complete watertight closure here. Typically these incisions will heal quite quickly. And we make sure we have adequate pressure in the eye at the end of the case. We typically stop the glaucoma medications and start frequent steroids postoperatively.
October 28, 2019