Impact of difficult unfolding and attachment of the graft lamella on the long-term outcome after Descemet membrane endothelial keratoplasty

Double-Bubble Technique Assisted by Holding Forceps: A Modified Technique in Descemet Membrane Endothelial Keratoplasty for Vitrectomized Eyes With Scleral Fixated Intraocular Lens

PURPOSE

Several techniques have been developed for graft unfolding approaches in Descemet membrane endothelial keratoplasty (DMEK). However, despite these techniques, graft deployment and configuration in eyes with deep anterior chambers remain challenging in some cases. Therefore, in this study, we described a modified technique for DMEK, known as the "double-bubble technique assisted by holding forceps."

METHODS

This was a retrospective interventional case series. Patients who underwent DMEK between August 2022 and July 2023, including cases with a history of vitrectomy and scleral fixation of intraocular lens, were enrolled in this study. Two experienced surgeons performed DMEK. In brief, after graft insertion into the anterior chamber, the first bubble with a small volume of air was injected above the graft to open the tight roll, and the graft edge was held using a 25-gauge graft manipulator. The second bubble was injected underneath the graft for fixation, while the graft edge was grasped using forceps during gas injection. The graft was released from the forceps. Best spectacle corrected visual acuity, central corneal thickness, endothelial cell density, and incidence of postoperative complications were measured before and after DMEK.

RESULTS

Eleven eyes of 11 patients were included in this study (mean follow-up period, 4.5 ± 4.4 months). Best spectacle corrected visual acuity and central corneal thickness significantly improved postoperatively ( P < 0.001). Rebubbling was required in 2 eyes; no other postoperative complications or primary graft failure were observed.

CONCLUSIONS

The present technique enables safe and feasible DMEK surgery in vitrectomized eyes with scleral fixated IOLs and in those with a deep anterior chamber.

DMEK surgical training: An instructional guide on various wet-lab methods

Descemet membrane endothelial keratoplasty (DMEK) is a partial-thickness corneal transplantation procedure that involves selective transplantation of the Descemet membrane and endothelium. DMEK offers significant advantages over other keratoplasty techniques, such as faster visual rehabilitation, better final visual acuity due to minimal optical interface effects, lower risk of allograft rejection, and less long-term dependence on topical steroids. Despite all its advantages, DMEK has been found to be more challenging than other corneal transplantation techniques, and its steep learning curve appears to be an obstacle to its widespread use and adoption by corneal surgeons worldwide. DMEK surgical training laboratories (wet labs) provide a window of opportunity for surgeons to learn, prepare, manipulate, and deliver these grafts in a risk-free environment. Wet labs are a significant learning tool, especially for those institutions that have limited tissue availability in their local centers. We provide a step-by-step guide for preparing DMEK grafts using different techniques on human and nonhuman models with instructional videos. This article should eventually help the trainees and the educators understand the requirements for performing DMEK and conducting a DMEK wet lab and develop their skills and interests from a wide variety of available techniques.

"The Spinning Technique" for Unfolding Tightly Scrolled DMEK Grafts

PURPOSE

We present a no-touch Descemet membrane endothelial keratoplasty (DMEK) technique which assists in unfolding of tightly scrolled grafts from young donors.

METHODS

The technique was developed following a wet-laboratory experiment using human corneas created to observe the behavior of the graft during spinning within the artificial anterior chamber. This approach involves injecting short bursts of balanced salt solution to make the scroll spin continuously in a 360-degree manner. Spinning of the graft over the surface is accompanied by rotation on its horizontal axis resulting in opening in the correct orientation. Unfolding is then completed with standard bimanual tapping maneuvers. The spinning technique was then performed in 4 patients who all had tight DMEK scrolls from young donors.

RESULTS

The wet laboratory confirmed that directed jets of fluid to generate spinning and rotation open the graft in the correct orientation in most occasions. All 4 cases in this study received grafts from young donors (range 37-48 years old), and the technique achieved rapid unfolding with no complications. Two of our patients had glaucoma drainage devices, 1 had anterior chamber intraocular lens, and all other cases had clear corneas and good endothelial cell count after the 1-year follow-up.

CONCLUSIONS

Our novel technique provides a safe and effective method to unscroll tight DMEK grafts that surgeons could incorporate into their armamentarium. Success is optimized by slightly undersizing the graft (7.5-8.0 mm).

Effect of Six-Month Postoperative Endothelial Cell Density on Graft Survival after Descemet Membrane Endothelial Keratoplasty

PURPOSE

To analyze if 6-month endothelial cell density (ECD) affects long-term ECD outcome and graft survival 5 years after Descemet membrane endothelial keratoplasty (DMEK) in eyes with Fuchs endothelial corneal dystrophy (FECD).

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 585 DMEK eyes were included. The study group was divided into 4 groups based on 6-month ECD quartiles: group 1 (n = 146) with 313 to 1245 cells/mm², group 2 (n = 148) with 1246 to 1610 cells/mm², group 3 (n = 145) with 1611 to 1938 cells/mm², and group 4 (n = 146) with 1939 to 2760 cells/mm². Group 1 was further split into subgroups 1a (n = 36) with 6-month ECD of ≤828 cells/mm², 1b (n = 37) with 829 to 1023 cells/mm², 1c (n = 37) with 1024 to 1140 cells/mm², and 1d (n = 36) 1141 to 1245 cells/mm².

METHODS

Descemet membrane endothelial keratoplasty.

MAIN OUTCOME MEASURES

Long-term ECD, graft survival, and postoperative complication rates.

RESULTS

For group 1, 6-month ECD decreased from 951 (±233) cells/mm² (n = 146) to 735 (±216) cells/mm² (n = 99) at 5 years postoperatively. Group 1 graft survival probability was 0.95 (95% confidence interval [CI], 0.91-0.99] at 5 years postoperatively, which was lower than for groups 2 to 4 (P = 0.001). Five-year graft survival in subgroup 1a was 0.79 (95% CI, 0.67-0.94), which was lower than in subgroups 1b to 1d (P = 0.001). Preoperative ECD did not influence graft survival (P = 0.400), and higher 6-month ECD values were associated with lower graft failure rates (hazard ratio, 0.994; 95% CI, 0.99-1.00; P = 0.001).

CONCLUSIONS

Six-month ECD is associated with DMEK graft survival. High early cell loss after DMEK negatively affects long-term ECD outcome and graft survival. Grafts in the lowest 6-month ECD subgroup (≤828 cells/mm²) are at higher risk of failure within 5 years after DMEK. To ensure sufficiently high 6-month ECD, preoperative graft quality assessment should be optimized, and cellular stress induced to the graft should be minimized. Additionally, developing therapeutic options for the treatment of low postoperative ECD could further improve DMEK graft longevity.

A Novel Technique for Donor Insertion and Unfolding in Descemet Membrane Endothelial Keratoplasty

PURPOSE

To describe a novel technique for insertion and unfolding of donor Descemet membrane (DM) scroll during DM endothelial keratoplasty (DMEK).

METHODS

DMEK was performed in 20 eyes. The donor DM scroll was loaded into a glass injector, and the fluid column was manipulated to achieve a double scroll configuration. After performing DM stripping and inferior iridectomy, an anterior chamber (AC) maintainer was placed in position. The glass injector was inserted into the AC and the tip rotated to ensure correct orientation of the DM scroll. After disconnecting the IV tubing from the AC maintainer, the donor DM scroll was delivered into the AC. Donor unfolding was performed using surface tapping techniques. An air bubble was injected under the graft to obtain a complete AC air fill. The outcomes of this surgical technique were analyzed.

RESULTS

Donor DM insertion and unfolding were performed without any complications in all eyes. Double scroll configuration of donor DM in the injector could be achieved in 17 of 20 eyes (85%). A controlled delivery, maintaining correct scroll orientation, was possible in all eyes. Intraoperative duration from insertion to unfolding was 252.7 ± 45.4 seconds. A clear cornea was achieved in all eyes, with 75% of eyes (15/20) achieving corrected distance visual acuity of 20/20 or better, at average follow-up duration of 13.3 ± 1.3 months. Endothelial cell loss at 6 months follow-up was noted to be 16.7%. Partial donor detachment was noted in 2 eyes (10%), which resolved spontaneously.

CONCLUSIONS

Our novel technique of donor DM insertion allows easy donor insertion and unfolding, thereby simplifying the DMEK procedure.