Aspiration of Tri-folded, Endothelium-In Grafts for Descemet Membrane Endothelial Keratoplasty

Clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) with imported donor corneas in eyes of Asian patients; endothelium-in versus endothelium-out method

Objective

We investigated whether (1) imported pre-cut tissue is feasible for Descemet membrane endothelial keratoplasty (DMEK) in eyes of Asian patients, (2) the clinical outcome is comparable between the endothelium‐in and endothelium‐out methods, and (3) the corneal edema-induced anterior curvature changes may have an effect on the refractive error.

Methods

The medical records of 32 DMEK patients who underwent either the endothelium-out or endothelium-in method using imported pre-cut grafts with a 3-day pre-cut-to-use time were retrospectively analyzed. Fuchs’ endothelial dystrophy (37.5%) and bullous keratopathy (62.5%) cases were included. The main clinical outcome measures were graft survival, best corrected visual acuity (BCVA), endothelial cell density (ECD), corneal thickness (CT), and complications. Correlation of the anterior curvature changes with refractive error was analyzed in the DMEK with cataract surgery group.

Results

The overall survival rate was 71.9%. Final graft failures were caused by rejection, glaucoma, and infection. Visual acuities improved by 89.3%. BCVA better than 20/40 and 20/20 was found in 75% and 28.6% of patients, respectively. The ECDs at 3 months and 1 year were 1400 and 1083 cells/mm², respectively. The mean survival time, ECD, BCVA, CT, and complication rates were not different between the endothelium-in and endothelium-out methods. A hyperopic shift by +0.42 D was not related to the anterior curvature changes.

Conclusion

Imported pre-cut tissues with a ≤ 3-day pre-cut-to-use time are feasible for DMEK in the treatment of corneal endothelial edema in eyes of Asian patients, and both endothelium-in and endothelium-out methods appear to be comparatively effective. Edema-induced anterior curvature change may not affect the refractive shift.

Viability of preloaded Descemet membrane endothelial keratoplasty grafts with 96-hour shipment

Objective

To assess feasibility and compare the effects of 96-hour shipment of Descemet membrane endothelial keratoplasty (DMEK) grafts as a scroll or a tri-fold on cell viability.

Methods and analysis

DMEK grafts were prepared at the Rocky Mountain Lions Eye Bank. Twenty pre-stripped DMEK grafts, paired from 10 donors, were either tri-folded in an endothelium-in configuration using microforceps and loaded into a plastic Treyetech cartridge, or suctioned in a scrolled endothelium-out configuration into a modified Jones Tube. Grafts were shipped via FedEx to a secondary location and back for 48 hours each way, resulting in a total shipping time of 96 hours. After shipping, grafts were removed from inserters onto glass slides and unfolded using viscoelastic with endothelium facing upwards. Calcein-AM stained grafts were imaged with a fluorescent microscope and endothelial cell loss (ECL) was measured using trainable segmentation in Fiji by a masked grader.

Results

A total of 20 grafts were shipped for 96 hours, split between preloaded tri-folded (n=10) and preloaded scrolled (n=10) tissues. No significant difference in ECL was observed across groups after prolonged shipping (14.8% vs 13.7% ECL respectively, p=0.68).

Conclusion

For preloaded DMEK after 96 hours, both scrolled and tri-folded tissue demonstrated clinically acceptable levels of ECL. The data suggest a wider window of time for endothelial cell viability and is promising for the prospect of international shipment of preloaded grafts.

Techniques, Outcomes, and Complications of Preloaded, Trifolded Descemet Membrane Endothelial Keratoplasty Using the DMEK EndoGlide

PURPOSE

To describe 2 insertion techniques, outcomes, and complications of preloaded, trifolded Descemet membrane endothelial keratoplasty (DMEK) cases using the DMEK EndoGlide inserter.

METHODS

This retrospective, consecutive case series analyzed the first 35 cases using the DMEK EndoGlide performed between October 2018 and October 2019 at a single center. Preloaded, trifolded DMEK tissues were delivered through a fluid-injected or pull-through technique. To inject the tissue, a burst of fluid was delivered into the lumen of the injector with a second instrument. Postoperatively, best-spectacle corrected visual acuity (BSCVA), pachymetry, graft survival, and complications were assessed.

RESULTS

Thirty-five eyes of 29 patients underwent DMEK alone (n = 11), with cataract surgery (n = 21), or with additional surgeries (n = 3). Of these, 19 (54.3%) grafts were injected. Video analysis revealed a median time of 3.5 minutes from graft insertion to opening for gas insertion. Median preoperative BSCVA of 0.398 logMAR improved to 0.097 logMAR (P = 0.02) at 9 months. Median pachymetry decreased from 619 μm to 551 μm (P = 0.03) at 9 months. Median donor endothelial cell count of 2890.5 cells/mm2 reduced to 2123 cells/mm2 (26.6% endothelial cell loss; P = 0.008) 6 months postoperatively. One (2.9%) graft failed due to inverted marking at the eye bank and subsequent reverse implantation.

CONCLUSIONS

Pre-loaded, tri-folded tissues can be implanted with acceptable levels of endothelial cell loss. We describe a no-touch method of injecting pre-loaded, tri-folded tissue and highlight incorrect marking as a potential complication. This may not be identifiable intraoperatively due to lack of scroll formation.

Preloaded Descemet Membrane Endothelial Keratoplasty Grafts With Endothelium Outward: A Cross-Country Validation Study of the DMEK Rapid Device

PURPOSE

To validate the "Descemet membrane endothelial keratoplasty (DMEK) Rapid" device for the cross-country transportation of preloaded DMEK grafts preserved with endothelium outward.

METHODS

DMEK grafts were stripped and loaded in the DMEK Rapid device with tissue culture medium (TCM) or transport medium (TM) with endothelium outward. The device was mounted in a 40-mL flask and preserved for 4 days on a rocker to simulate transportation (study A, n = 24) or shipped in the TM from Italy to the United Kingdom (study B, n = 9) and evaluated within 72 hours. All the tissues were stained with Alizarin red. Viability of the cells was checked postsimulations and posttransportation and was confirmed using live/dead staining. Expression of tight junction proteins was evaluated.

RESULTS

In study A, the endothelial cell loss observed from the TCM group was 20.8% (±5.2) compared with 19.5% (±6.7) from the TM group (P = 0.41) after transport simulation. Alizarin red showed minimal uncovered areas in both groups. There were no statistical differences in viability between the TM (80.83%) and TCM groups (78.83%). In study B, 12.9% (±7.8) endothelial cell loss was observed after transporting the tissues from Italy to the United Kingdom with no significant difference between prestrip and posttransportation (P = 0.05). Alizarin red staining did not show any uncovered area. Live/dead analysis showed 85.16% cell viability after transportation. zonula occludens-1 (ZO-1) was expressed in all tissues.

CONCLUSIONS

The DMEK Rapid device is safe for preloading and shipping DMEK grafts internationally with endothelium outward within 72 hours when preserved in the transport media.

Preloading Trifolded Grafts for Descemet Membrane Endothelial Keratoplasty Affects Scroll Formation

PURPOSE

The trifolded, endothelium-in approach to Descemet membrane endothelial keratoplasty (DMEK) facilitates tissue insertion into the anterior chamber. We hypothesized that preloading the trifolded donor grafts in a cartridge for 48 hours before insertion would induce biomechanical changes that decrease their scrolling tendency compared with those loaded immediately before insertion.

METHODS

Ten Descemet membrane donor grafts, peeled and cut to 8.0 mm, were prepared by a single eye bank technician. Each graft was trifolded and pulled into a DMEK cartridge and stored for 48 hours. They were then pulled with microforceps into a petri dish filled with balanced salt solution. A video was recorded of the graft becoming a scroll over a 2-minute period. Each graft, serving as its own control, was then trifolded, pulled into the cartridge, and the process repeated. Images from 1, 5, 10, 60, and 120 seconds were extracted from video recording of the procedures. Scroll width was analyzed by graders masked to group assignment. A paired t test was used to determine differences in scroll width at each time point between the 48-hour and instant trifolding conditions.

RESULTS

All grafts scrolled after removal from the cartridge into balanced salt solution. We measured a significant difference at all time points 1 through 120 seconds (4.02 preloaded vs. 2.91-mm instant trifold, P = 0.035).

CONCLUSIONS

Preloading DMEK grafts in a trifolded configuration for 48 hours reduces the scrolling tendency of Descemet membrane for at least 2 minutes.

"Double-Bubble" Descemet Membrane Endothelial Keratoplasty Unfolding in Eyes With Deep Anterior Chambers and Anterior Chamber Intraocular Lenses

PURPOSE

To describe a standardized technique for Descemet membrane endothelial keratoplasty unfolding in eyes with deep anterior chambers and anterior chamber intraocular lenses (ACIOLs).

METHODS

Two air bubbles are used simultaneously: the first placed on top of the graft and the second one underneath.

RESULTS

The 2 bubbles work in concert-the bubble on top props the tissue partially open, while the bubble underneath levitates the graft away from the ACIOL and provides support for subsequent unfolding maneuvers.

CONCLUSIONS

By sandwiching the graft between 2 bubbles, unfolding may proceed away from physical contact with the ACIOL, even in eyes with hyper-deep chambers.