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Two-forceps stripping and orientation-marking techniques make DMEK donor preparation easier, safer
This method limits tissue loss and ensures proper graft orientation.
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BERLIN — Donor preparation and correct orientation of the endothelial graft are crucial steps for successful Descemet’s membrane endothelial keratoplasty, according to a surgeon here.
“In order to reduce tissue loss during preparation, we perform the procedure underwater. This eliminates surface tension and keeps the tissues well hydrated and therefore more resistant to tearing,” Friedrich Kruse, MD, said at the World Ophthalmology Congress.
A round blade is used to create a small groove and then loosen the edges of Descemet’s membrane with a perpendicular movement, 360° around the circumference. Trypan blue staining can be used to facilitate this maneuver.
“At this point we use not one but two forceps, to distribute the tension and therefore minimize the stress and the risk of tearing. We remove the tissue up to almost the center. Then we do a trephination,” Dr. Kruse explained.
One of the problems with Descemet’s membrane endothelial keratoplasty is loss of the correct anterior-posterior orientation during implantation of the Descemet’s graft. Dr. Kruse and colleagues have introduced a marking technique using a 1-mm punch to create three small marks at the edge of the transplant.
“Before stripping is completed, three circular marks are created in an identifiable order at the edge of the donor disc. When we attach the graft to the host cornea, it is easy to identify the anterior-posterior orientation by the clockwise order of the three marks,” he explained.
 Partial removal of endothelial-Descemet’s membrane with two forceps. |
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Removal of the Descemet’s lamella with
two rather than one forceps allows a better distribution of forces.
Images: Kruse F
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After marking, the Descemet’s lamella is removed completely with the two forceps. By using the round-blade technique in conjunction with the two-forceps technique, tissue loss is reduced to less than 1%, Dr. Kruse said. Histological investigation also showed that this preparation technique does not harm the endothelium.
“We prepare the graft immediately prior to transplantation, which is a different approach to Melles’ original technique,” he said.
The donor graft is then loaded in an Acri.Tec IOL injector (Carl Zeiss Meditec), taking great care in keeping the correct orientation. It is inserted into the anterior chamber, unfolded with the help of air bubbles and pushed against the host corneal stroma by air injection.
“Thanks to our marking technique, after surgery we are 100% certain of how the endothelium is oriented,” Dr. Kruse said. – by Michela Cimberle
Reference:
- Bachmann BO, Laaser K, Cursiefen C, Kruse FE. A method to confirm correct orientation of descemet membrane during descemet membrane endothelial keratoplasty. Am J Ophthalmol. 2010 Jun;149(6):922-925.
- Friedrich Kruse, MD, can be reached at Augenklinik mit Poliklinik, Schwabachanlage 6, 91054 Erlangen, Germany. +49 -9131-8534477; fax +49-9131-8536435; e-mail: friedrich.kruse@uk-erlangen.de.
