When developing the procedure needed to perform a safe DSAEK, early on it was apparent to me that maintaining the anterior chamber was preferable to collapsing it. I have traveled the world watching skilled surgeons and was always impressed by those preserving the anterior chamber with a maintainer, forgoing the use of viscoelastic. Years ago, I started using anterior chamber maintainers due to concerns about viscoelastics. It was a stepwise realization that DSAEK could be adapted to this technology. The problem was creating enough flow due to the leaky nature of the larger incisions and cumbersome instruments. Using two thin walled high flow anterior chamber maintainers solved part of the inflow problem.
Another issue was the use of a forceps to introduce the graft. Fluid tends to escape between the jaws of normal forceps as they fish mouth the wound. By using a retina style enclosed long forceps modified for the folded graft, the wound is less deformed. I developed a pipe like device modified for this application which keeps the wound from opening and the outflow nominal, maintaining the chamber during introduction of the graft.
Some of my earliest patients had advanced Fuchs dystrophy and no cataracts. I had been warned that the standard procedure was not possible in a phakic eye and this bothered me greatly. My objective was to develop a technique that would allow me to use this procedure for phakic eyes. It represents an advance in the ability to do DSAEK on phakic and pseudophakic eyes with less damage to the endothelium of the graft, better handling techniques and improved results. With the double barrel DSAEK, we have been able to do several phakic eyes avoiding the need for cataract and multiple procedures.
In the most standard case, the patient has late stage Fuchs’ endothelial dystrophy and is usually status post bilateral cataract surgery. It is common to find patients like this with visions that have dropped to 20/100 or worse. The underlying method here involves using high volume (thin walled, low gauge) chamber maintainers. The “double barrel” use of two irrigating, anterior chamber maintainers allows preservation of the chamber for the two handed placement of the endothelial graft. The procedure for providing the endothelial graft is standard. A Moria microkeratome is used to make the 300 micron stromal flap. A Hanna trephine is used to make the 8.75 donor specimen. This is prepared in a sterile manner under the microscope and brought to the operating area. The recipient bed is then prepared and a reverse Sinskey is used to do the 360 degree Desmeto-rhexis with Siepser shielded luminary light probe (Escalon Trek) to better illuminate the flap as it is created. All room illumination is diminished and the illuminator is used to better visualize the Descemet’s membrane. The Escalon Medical Corporation Siepser shielded probe R9879-11 was used. This probe was designed to achieve better contrast by shielding the surgeon’s eyes from the high level blue spectrum light. The probe illuminates much like a ‘58 Chevy visored headlamp in that it guards the surgeon’s eye from direct illumination of the illuminating tip. With indirect Tindal effect lighting, visualization of the endothelial graft is much improved. Photos demonstrate this easily see figure: ….. Once the endothelium is removed, and the Desmeto-rhexis is complete, Descemet’s membrane can be inspected on the surface of the cornea to verify the extent of removal. Stab incisions are made in the cornea at the 6mm diameter at 4:00, 7:00 and 11:00 for removal of fluid and better dehydration of the interflap area once the graft is placed. The graft is then folded and placed in the modified Siepser DSAEK graft introducer and carefully brought to the operative site. The Siepser introducer is then carefully inserted in a fairly swift motion through the 3.5 mm incision site. The anterior chamber remains deep due to the constant irrigation and the pipe like structure to the introducer. The Siepser introducer cannot be removed from the eye until the graft is grasped with the other hand, in this case, to stabilize it within the eye. A Moria “iris grabber” is ideal for this maneuver. The introducer is then removed from the eye when the graft is fully stabilized with the opposing hand. The wound self seals with hydration. The chamber deepens immediately and the graft unfolds. Air is then injected underneath the graft and it is positioned carefully. The interface area is drained using Sinski hook and a Weck-cel and graft stabilization is achieved. Full air is injected for stabilization of the graft in the globe. The patient is able to leave the operating room immediately. We tend to allow the patient to depart in 30 minutes once we have removed excess air at the slit lamp. We are carefully tracking the cell counts, visual acuities and graft survival.