EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/76185
16 EW NEWS & OPINION July 2012 Tools & techniques EndoGlide inserter technique for DSAEK surgery by Donald Tan, F.R.C.Ophth. P osterior lamellar keratoplasty proce- dures such as DSAEK have revolu- tionized corneal transplantation. The giant leap from penetrating keratoplasty to DSAEK has now been refined with small incremental improvements in technique and instrumentation. Although many corneal surgeons are still using folding forceps for insertion of the delicate posterior grafts, insertion devices that can simplify the procedure and possibly yield lower rates of endothelial cell loss have sparked renewed interest in cartridge injectors as a means of implanting DSAEK grafts. In this month's column, Donald Tan, F.R.C.Ophth., describes the step-by-step approach for utilizing the Tan EndoGlide inserter. The newer EndoGlide UT for ultra- thin DSAEK will be especially valuable for those surgeons transitioning to this refine- ment of the traditional DSAEK procedure. Richard Hoffman, M.D., Tools & techniques editor Figure 1. As the donor is drawn into the cartridge, flipping the edges inward with a cannula helps to coil the tissue S everal different inserter devices have become available to help the sur- geon during implantation of the donor lenticule dur- ing DSAEK/DSEK. However, despite their use for over 2 years, there are very few published clinical studies demonstrating the outcomes of their use. One of the few inserters that has been used clinically that is both FDA and CE approved and with pub- lished clinical outcomes is the Tan EndoGlide (Angiotech, Reading, Pa.). The device is a single-use deliv- ery system for simplified insertion of DSAEK donor tissue, which mini- mizes endothelial cell damage, with reported endothelial cell loss in the region of 15% at 6 months post-op. Two versions of the EndoGlide are now available: the EndoGlide Classic for normal thickness donors and the EndoGlide Ultrathin (UT) for ultrathin DSAEK. DSAEK surgery using the EndoGlide Classic Recipient preparation: Donor insertion with the EndoGlide is performed through either a shelved 4.5 mm temporal scleral wound or through a 5 mm clear cornea tempo- ral tunnel. An anterior chamber (AC) maintainer is useful and may be placed at one side of the incision. A 1.5 mm nasal paracentesis is used to allow introduction of the curved EndoGlide insertion forceps to pull the donor tissue into the AC. Donor loading into the EndoGlide: Donor loading is best performed under the operating mi- croscope with the preparation base positioned on a stable, sterile sur- face. The EndoGlide comes with the donor cartridge preloaded on the Figure 2. Fixing the introducer to the back end of the cartridge creates a tight seal, and the EndoGlide can be withdrawn from the preparation base, inverted the right way up, and inserted into the eye preparation base. A small volume of balanced salt solution is first in- jected into the inner chamber of the cartridge for lubrication. The precut donor cornea, comprising both ante- rior and posterior lenticules, is then placed endothelium up within the well of the preparation base. It is useful to gently loosen the lenticules from each other prior to donor placement. The EndoGlide is designed to enable insertion of a corneal donor up to 10.0 mm in diameter and up to 250 µm in thick- ness. A small strip of dispersive vis- coelastic is placed on the endothelial surface of the posterior lenticule. The EndoGlide straight loading for- ceps is introduced through the ante- rior opening of the cartridge into the chamber and is used to grasp the leading stromal edge of the posterior lenticule, which can then be care- fully pulled into the cartridge. As the donor enters the capsule, it will coil, and the sides of the donor will natu- rally curl upward along the inner sidewalls of the cartridge. It is important to facilitate this coiling process by gently flipping up the tissue edges as they coil, using a cannula or Sinskey hook (Figure 1). As the donor coils in, the coiling edges will encounter a central inner ridge on top of the cartridge and automatically roll inward, creating a double coil configuration that pre- vents endothelial-stromal contact. The donor tissue is pulled through until the leading anterior edge just reaches the anterior opening of the cartridge, and the forceps can be carefully withdrawn. The anterior lenticule left behind is then re- moved from the well of the prepara- tion base, and the introducer handle (with the word "CORONET" facing Figure 3. After fully inserting the EndoGlide, forceps are used to pull the donor into the eye in a controlled manner up) is slid into position, engaging the posterior end of the cartridge, until there is an audible click indi- cating the introducer is locked onto the cartridge and fully seals the back end of the cartridge (Figure 2). The loaded cartridge, with the introducer attached, may now be removed in its entirety from the preparation base and is turned right side up for the proper orientation and is ready for insertion into the recipient eye. Donor insertion: With the AC maintainer on low to moderate flow, the flat anterior glide portion of the cartridge is inserted through the temporal wound and advanced into the AC. The flat surface of the glide prevents iris prolapse through the wound. The cartridge is advanced until the entire opening of the car- tridge is advanced all the way into the AC, providing a tight seal. With one hand holding the EndoGlide, the curved EndoGlide insertion for- ceps is inserted into the AC through the nasal paracentesis with the other hand. The forceps is advanced over the glide into the anterior opening of the capsule, used to grasp the stromal edge of the donor, and then used to gently pull the donor tissue out of the cartridge chamber into the AC (Figure 3). Once the donor tissue is fully removed from the car- tridge, it will automatically start to uncurl, endothelial side down. While still holding onto the donor with the forceps, the EndoGlide cartridge is then removed from the wound. Gentle sideways shaking of the donor with the forceps as well as tapping on the corneal surface will assist in full uncoiling of the donor. While still holding onto the donor, a small air bubble is injected beneath the donor, through the wound, to