Standardized ‘no‐touch’ donor tissue preparation for DALK and DMEK: harvesting undamaged anterior and posterior transplants from the same donor cornea

Abstract

. Purpose: To describe a standardized ‘no‐touch’ harvesting technique of anterior and Descemet membrane (DM) grafts for use in deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK), which provides undamaged anterior and posterior corneal grafts. Methods: A retrospective evaluation was performed of our standard method for harvesting DM grafts and DALK grafts (Technique I; n = 31) versus a newly designed ‘no‐touch’ technique (Technique II; n = 31), in which a peripheral ring of trabecular meshwork tissue is left in‐situ, and the DM graft is trephined on an underlying soft contact lens. Endothelial cell density (ECD) before and immediately after DM stripping was used as the main outcome parameter. Results: Endothelial cell density did not differ within Techniques I and II (before versus after DM stripping) (p = 0.75 and p = 0.54, respectively) or among Techniques I and II (p = 0.61). With the latter technique, anterior corneal grafts and posterior DM grafts could be harvested with negligible damage to the endothelial cell layer or the posterior stromal bed. All 93 grafts (62 DM grafts) were eligible for transplantation, and six months post‐operatively all transplants used were functional. Conclusion: The new technique offers the following advantages: (i) production of ‘undamaged’ grafts for DALK and DMEK, (ii) better controlled tissue handling of the thin DM graft during DM stripping and (iii) an increase in availability of corneal grafts obtained from the same donor tissue pool.

Clinical Outcome of 500 Consecutive Cases Undergoing Descemet's Membrane Endothelial Keratoplasty

“…10,12 Corneoscleral buttons were excised from donor globes 36 hours postmortem and stored by organ culture at 31 C. After 1 week of culture, endothelial cell morphology and viability were evaluated and the corneoscleral buttons were mounted endothelial side up on a custom-made holder. A 9.5-mm diameter Descemet's sheet with its endothelium was removed from the posterior stroma with the corneoscleral rim immersed in balanced salt solution.…”

“…8 The latter technique has shown potentially better visual outcomes, and after an initial learning curve, DMEK evolved into standardized, "no-touch" procedures, for both the surgery itself 9 and the dissection of a donor DM from a corneoscleral rim. 10 Standardization also greatly facilitated teaching these techniques to corneal fellows and corneal surgeons starting out with DMEK. Furthermore, various risk factors were recognized (e.g., not performing the descemetorhexis under air, the use of plastic material and viscoelastics) and, if possible, eliminated to minimize intraoperative and postoperative complications.…”

Descemet Membrane Endothelial Keratoplasty—A Review

“…[24][25][26][27][28] Recently, the process was upgraded to a 'no-touch' procedure, making the preparation both safer and easier. 29 As a bonus, the anterior portion of the corneas left over from creating the DMEK grafts (with the Descemet membrane stripped off, but otherwise intact) can be used for deep anterior lamellar keratoplasty (DALK). This added benefit applies only to DMEK, because DS(A)EK preparation - by incorporating some of the posterior stroma into the graft -mangles the corneal remains, leaving them less suitable for transplant.…”

La estandarización en el trasplante endotelial de membrana de Descemet: resultados de las primeras 450 cirugías

“…Actualmente la DMEK es una técnica que se puede realizar sin ningún contacto directo («no touch» en inglés) con el tejido, de forma estandarizada y reproducible 20 , que podría ser el tratamiento de elección de las enfermedades del endotelio corneal frente al resto de trasplantes endoteliales 18,22 . Los objetivos del presente estudio fueron, por una parte, describir los resultados de 450 cirugías DMEK para el tratamiento de la distrofia endotelial de Fuchs, la queratopatía bullosa seudofáquica y el fracaso del injerto tras una queratoplastia endotelial en términos de AVMC, celularidad del injerto y complicaciones posquirúrgicas; por otra parte, se pretendió evaluar los efectos de la estandarización de la técnica quirúrgica: para ello se realizó la división de la muestra en 3 subgrupos: el subgrupo i incluyó las primeras 125 DMEK como representación de una prolongación de la curva de aprendizaje; el subgrupo ii incluyó las siguientes 125 DMEK, representando la transición hacia la estandarización de la téc-nica; y el subgrupo iii, incluyendo las últimas 200 DMEK, como muestra de la técnica estandarizada.…”