Membrane Endothelial Keratoplasty Graft Preparation Research Articles

Influence of Descemet Membrane Endothelial Keratoplasty Graft Preparation Patterns on Postoperative Clinical Outcome.

The aim of this study was to quantify preparation difficulties and complications during DMEK graft preparation and their influence on clinical outcome. A retrospective evaluation of 214 consecutive DMEK surgeries from the prospective Cologne DMEK database was performed between July 2018 and December 2019. Preparation conditions (such as central and peripheral adherences, tissue fragility, and Descemet membrane splitting) were quantified and divided into 3 groups: easy, difficult, and very difficult preparation. At follow-up (3, 6, and 12 months after DMEK), best spectacle-corrected visual acuity, endothelial cell count (ECC), and rebubbling rates were evaluated and compared between groups. An easy preparation was possible in 41.6% of cases (group 1, n = 89), a difficult preparation of the DMEK graft occurred in 30.8% (group 2, n = 66), and a very difficult preparation occurred in 27.6% (group 3, n = 59). There was no difference between groups for best spectacle-corrected visual acuity at 3, 6, and 12 months ( P = 0.179, P = 0.325, and P = 0.682, respectively) or for ECC at 3 and 6 months ( P = 0.537 and P = 0.606, respectively). Only at 12 months, the ECC was slightly significant between groups ( P = 0.045). Regarding the rebubbling rate, there was no difference ( P = 0.585). 17.9% of eyes from group 1, 25.7% of eyes from group 2, and 23.7% of eyes from group 3 received at least 1 rebubbling. These data suggest that difficult preparation conditions do not lead to any worsening of visual acuity or rebubbling rate in the 1-year outcome after DMEK. The endothelial cell density at 12 months showed slightly poorer results in the cases of very difficult preparation.

Yogurt Technique for Descemet Membrane Endothelial Keratoplasty Graft Preparation: Early Clinical Outcomes.

The aim of this study was to evaluate the efficacy and safety of the Yogurt technique for Descemet membrane endothelial keratoplasty (DMEK) graft preparation. This study included patients who underwent DMEK combined or not with phacoemulsification surgery using donor tissues prepared by a surgeon with the DMEK Tzamalis disposable punch at 2 referral hospitals between October 2019 and June 2021. Primary outcomes were duration of graft preparation, surgeon grading of graft quality, and endothelial cell density measured at 1 and 6 months after surgery. Secondary outcomes were best-corrected visual acuity (BCVA) measured at 1 and 6 months postoperatively and DMEK intraoperative and postoperative complications. Forty-nine patients were included in this study. The mean DMEK graft preparation time was 7.2 ± 1.4 minutes. Donor grafts were rated good in 67.3% of cases (33 of 49), sufficient in 24.5% (12 of 49), and poor in 8.2% (4 of 49). Donor mean endothelial cell density was 2580 ± 155 preoperatively, which were reduced to 2269 ± 191 ( P < 0.000) and 1697 ± 142 ( P < 0.0001) at 1 and 6 months, respectively. No significant difference was found in graft preparation outcome ( P = 0.543). The preoperative BCVA was 0.65 ± 0.44 logMAR, which improved to 0.31 ± 0.43 logMAR ( P < 0.0001) and 0.12 ± 0.14 logMAR ( P < 0.0001) at 1 and 6 months after surgery, respectively. This study shows that the DMEK Tzamalis punch can be used as an effective and safe method for DMEK graft preparation with a shallow learning curve that allows it to be successfully performed by relatively inexperienced surgeons.

Comparative evaluation of four Descemet membrane endothelial keratoplasty graft preparation techniques

ObjectifComparer les résultats subjectifs et objectifs de 4 techniques de pelage dans la kératoplastie endothéliale de la membrane de Descemet (DMEK) réalisées par des chirurgiens débutants à différentes étapes de leur carrière chirurgicale. NatureÉtude prospective ex vivo. MéthodesLors d'un premier tour, on a comparé 4 techniques de pelage, en opposant 2 techniques entre elles: la dissection périphérique réalisée à l'aide du crochet de Sinskey contre la dissection périphérique réalisée à l'aide d'un microhoe, d'une part, et la dissection périphérique réalisée à l'aide d'un microhoe émoussé contre la résection de l’éperon scléral réalisée à l'aide d'un microhoe, d'autre part. Trois chirurgiens de niveaux d'expérience différents ont réalisé le pelage. Au nombre des paramètres de mesure, mentionnons le temps de pelage du greffon, le degré de difficulté à réaliser le pelage ressenti par le chirurgien (sur une échelle de 1 à 10, 1 correspondant au degré le moins élevé de difficulté et 10, au degré le plus élevé), le nombre de déchirures radiales et circonférentielles avant et après la trépanation et la perte de tissu. Les deux techniques qui ont donné les meilleurs résultats lors du premier tour ont été comparées dans le cadre d'un dernier tour afin d'identifier la meilleure technique globale. RésultatsAu total, 3 chirurgiens ont réalisé le pelage de 90 tissus (45 paires). À la suite des résultats du premier tour, la dissection périphérique réalisée à l'aide du crochet de Sinskey et la dissection périphérique réalisée avec un microhoe émoussé ont été retenues pour le dernier tour. On n'a pas enregistré de différence significative entre les groupes quant au temps de pelage, au degré subjectif de difficulté, aux déchirures post-trépanation et au taux de réussite du pelage (p > 0,05 pour l'ensemble des mesures). Cela dit, la dissection périphérique réalisée à l'aide du crochet de Sinskey a entraîné significativement moins de déchirures radiales (1,3 ± 1,3 vs 6,1 ± 5,2; p = 0,007) et circonférentielles (0,6 ± 0,9 vs 1,8 ± 2,1; p = 0,02) avant la trépanation. ConclusionsNotre étude permet de constater que la courbe d'apprentissage peut être aplanie rapidement grâce à l'utilisation de techniques de pelage appropriées dans la DMEK. La technique reposant sur la dissection périphérique réalisée à l'aide du crochet de Sinskey donne lieu à un pelage efficace qui s'accompagne d'un moins grand nombre de déchirures.

Evaluation of Efficacy, Efficiency, and Cell Viability of a Novel Descemet Membrane Endothelial Keratoplasty Graft Preparation Device, DescePrep, in Nondiabetic and Diabetic Human Donor Corneas.

The purpose of this study was to evaluate the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft preparation device, DescePrep, through measurement of graft viability, yield, and preparation time in both healthy and diabetic (high-risk) donor eyes. Twenty nondiabetic and 10 diabetic donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Corneas were stained with trypan blue and then processed. Cell counts through specular microscopy, optical coherence tomography imaging, and slit-lamp analysis were used for the evaluation of graft separation and viability in 5 nondiabetic corneas. The remaining 25 corneas (15 nondiabetic and 10 diabetic) were evaluated for preparation success rate and processing time. Ten corneas (5 nondiabetic and 5 diabetic) were randomly selected for further evaluation of global cell loss through staining. Ninety-seven percent of corneas (29 of 30) were prepared successfully with DescePrep. The average preparation time was 2.83 ± 1.8 minutes. There was no significant difference in the time of preparation between the nondiabetic and diabetic groups (P = 0.077). The overall average cell death after processing was 7.9% ± 3.7% for all corneas. There was no significant difference in cell viability between diabetic and nondiabetic tissues after DescePrep processing (P = 0.769). DescePrep is a new DMEK preparation technique that can process both nondiabetic and diabetic donor corneas at high yields in minutes. High-yield preparation of diabetic corneas may offer eye banks access to a larger donor pool, which is important because the demand for DMEK grafts continues to rise worldwide.

Ink Retention and Endothelial Cell Viability After the Application of an Orientation Stamp Over an Air Bubble During Descemet Membrane Endothelial Keratoplasty Graft Preparation.

To investigate stamp visibility and endothelial cell loss (ECL) after the application of an orientation mark to Descemet membrane endothelial keratoplasty (DMEK) grafts supported by an air bubble. Eighteen DMEK grafts were prepared at an eye bank using a technique where an orientation mark was applied to the stromal surface of a DMEK graft that was supported by a small air bubble placed at the edge of the 2 endothelial surfaces of the graft. Grafts were evaluated at 2 and 5 days for stamp visibility and at 5 days with calcein-AM staining for ECL. Nine grafts underwent cross-country shipping, and the ECL of shipped and nonshipped grafts was compared using unpaired t test. All 18 DMEK grafts exhibited a single, solid, readily visible orientation mark 2 and 5 days after preparation with a mean ECL of 13.5% ± 4.9%. Shipping conditions had no effect on stain retention or ECL. The application of an orientation stamp to a DMEK graft over an air bubble in an eye bank setting results in a single, solid orientation mark that is readily visible within the period in which most eye bank-prepared tissue is used. This technique produces no further ECL compared with the methods where the orientation stamp is applied through a stromal window. Eye bank technicians and surgeons can be confident that this modified preparation technique results in transplant-quality DMEK grafts with the additional benefit of conserving the stromal cap for use in other anterior lamellar procedures, thereby making efficient use of donor tissue.

The "Yogurt" Technique for Descemet Membrane Endothelial Keratoplasty Graft Preparation: A Novel Quick and Safe Method for Both Inexperienced and Senior Surgeons.

To describe and evaluate the efficacy and safety of a novel technique to prepare Descemet membrane endothelial keratoplasty (DMEK) donor grafts using a newly designed partial-thickness hinge punch. The novel punch has a circular guarded blade missing 1 clock hour, creating an uncut hinge on the donor cornea. In addition, 2 straight cuts are made by the punch perpendicular to the edge of trephination toward the trabecular meshwork in the hinge area. After the donor corneoscleral rim is positioned endothelial side up, a partial-thickness trephination is performed avoiding any rotational movements. Descemet membrane is lifted from Schwalbe line in the hinge area, and DMEK graft is peeled after desired marking without further preparation. Three surgeons of different experience levels on DMEK (senior/independent/fellow) initially applied the new technique in 18 research corneas, divided into equal groups. Two failures in graft preparation were noted, defined as radial tears extending ≥0.5 mm. The mean preparation time was 6.21 ± 1.45 minutes. No statistically significant differences were noted in success rate, duration, and endothelial cell loss (ECL) between surgeons (P > 0.05). ECL was evaluated as an average of 5 readings on randomly selected graft areas, not including graft periphery. Fifteen additional research corneas were stripped by 1 single user in an eye bank setting. No tissue loss was recorded, whereas ECL and mortality rate remained unaffected after preparation (P = 0.64 and P = 0.72, respectively). This new DMEK graft preparation technique, simulating the opening of a yogurt cup, seems to be a safe and an efficient method, providing shorter preparation time and low failure rates independent of surgeon's experience level.

Learning curve of two common Descemet membrane endothelial keratoplasty graft preparation techniques

To compare the learning curve of two Descemet membrane endothelial keratoplast (DMEK) graft preparation techniques. Experimental study. Twenty paired donor corneoscleral rims. The corneas were randomized to DMEK peeling using the peripheral blunt dissection technique (n = 10) or the modified submerged cornea using backgrounds away (mSCUBA) technique (n = 10). Outcome measures included graft peeling time, surgeon's peeling difficulty grading (on a scale of 1 to 10, 1 being the easiest and 10 the hardest), number of tears, and percentage tissue loss. Average graft peeling time using the peripheral blunt dissection technique and the mSCUBA technique was 15.75 ± 4.01 minutes and 8.43 ± 3.26 minutes, respectively (p < 0.0005). The first 3 grafts' average peeling time was longer than the last 7 grafts: 19.14 ± 2.40 versus 14.21 ± 3.50 minutes in the peripheral blunt dissection technique (p = 0.06) and 12.36 ± 3.76 versus 6.67 ± 0.49 minutes in the mSCUBA technique (p = 0.016). In the latter, there were significantly fewer radial tears compared to the former: 1.5 ± 1.0 and 3.1 ± 1.9, respectively (p = 0.049). No tissue loss was noted in the mSCUBA group compared to one (10%) in the peripheral blunt dissection group. The average difficulty grading for the mSCUBA was significantly lower than the peripheral blunt dissection technique: 3.3 ± 1.9 and 5.8 ± 1.6, respectively (p = 0.024). Our study suggests a shorter learning curve with the mSCUBA technique for DMEK graft preparation, with shorter peeling time and fewer complications in comparison to the peripheral blunt dissection technique.