Two-handed double-barreled DSAEK maintains anterior chamber

Technique offers less damage to the endothelium of the graft, better handling and improved results.

Issue: July 10, 2008

BySteven B. Siepser, MD, FACS

Early on, when developing the procedure needed to perform a safe Descemet’s stripping automated endothelial keratoplasty, 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.

Steven B. Siepser

Years ago, I started using anterior chamber maintainers due to concerns about viscoelastics. It was a stepwise realization that Descemet’s stripping automated endothelial keratoplasty (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 forceps to introduce the graft. Fluid tends to escape between the jaws of normal forceps as they fish mouth the wound. By using 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 that 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-barreled” DSAEK, we have been able to do several phakic eyes, avoiding the need for cataract extraction and multiple procedures.

The procedure

In the most standard case, the patient has late-stage Fuchs’ endothelial dystrophy and usually has had bilateral cataract surgery. It is common to find patients such as 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-µm stromal flap. A Hanna trephine is used to make the 8.75-mm donor specimen or equivalent after corneal measurement, keeping the donor almost 1 mm smaller than the anterior chamber diameter. 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 hook is used to do the 360· “descemetorhexis” with the aid of the 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 Corp. Siepser shielded probe R9879-11 is used. This probe was designed to achieve better contrast by shielding the surgeon’s eyes from the high intensity blue spectrum metal halide light source. The probe 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.

Once the endothelium is removed and the descemetorhexis 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 6-mm diameter at 4, 7 and 11 o’clock positions 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.

	A Siepser Shielded Luminary Light probe is used to fully define and illuminate Descemet’s stripping. The OR lighting is off and the direct microscope lighting is not used. The probe is powered by a Welch Allyn high intensity metal halide light source nearer the blue spectrum, increasing the scatter effect and the surgeon’s ability to see Descemet’s. Images: Siepser SB
Two large bore, thin-walled self-retaining anterior chamber maintainers are introduced in the inferior quadrants. They are each attached to a balanced salt bottle that is raised to its maximum height of 85 inches above the patient’s eye. Placement of these cannulas assures that the anterior chamber can be maintained with high-volume flow. This keeps a normal anterior chamber depth during intraocular maneuvers.	This shows placement of the cannulas inferiorly at the limbus and stabilized in the corneal 1-mm diamond knife paracentesis openings to the anterior chamber. The eye is approached with the graft material for this left eye held in the left hand using the Siepser DSAEK introducer (Moria) and introduced through a 3-mm incision. The right grabber is then introduced to hold the graft in place while the left instrument is removed from the eye.
This image illustrates the final position of the graft prior to air injection and removal of the chamber maintainers.	This operating microscope view shows the left hand introducing the graft into the anterior chamber through a 3-mm incision. The instrument on the right is introduced into the anterior chamber to grasp the graft while the left hand is removed, keeping the chamber formed even in phakic eyes.

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 chamber deepens immediately and the graft unfolds. The inferior chamber maintainers are sequentially removed and sealed with hydration. The incision sites also self-seal with hydration. Air is then injected underneath the graft as it is carefully centered. The interface area is drained using a Sinskey hook and a Weck-Cel, drawing aqueous through the more central corneal incisions for graft stabilization. Fluid-air exchange is completed to achieve good stabilization of the graft against the internal surface of the cornea. The globe is left relatively firm and watertight at the end of the procedure.

After surgery

The patient is able to leave the operating room immediately upon completion of the procedure. We tend to allow the patient to depart the surgery center in 30 minutes, once we have removed excess air at the slit lamp to avoid pupillary block. We are carefully tracking the cell counts, visual acuities and graft survivals. When our data meet more statistically significant levels later next year, we will report the findings.

This procedure takes less than 15 minutes in our hands. As a result, it seems at this early stage that there is better graft survival and success. We hope our colleagues can adapt this advance using new instrumentation to further improve the results of this amazing procedure.

For more information:

Steven B. Siepser, MD, can be reached at 860 E. Swedesford Road, Wayne, PA 19087; 610-265-2020; fax: 610-265-4054; e-mail: ssiepser@clear-sight.com. Dr. Siepser receives minimal royalties for the instrumentation made by Escalon Trek and Moria.