Authors (including presenting author) :
CHOW Y (1), LEUNG KP (1), TO W (1), CHOW WS (1,2), WONG SM (1), HUNG CS (1), TING MY (1)
Affiliation :
(1) Hospital Authority Eye Bank, Hong Kong (2) Hong Kong Eye Hospital
Introduction :
Hospital Authority Eye Bank (HAEB) has provided Descemet’s Membrane Endothelial Keratoplasty (DMEK) grafts with S-mark stamping by through a stromal-hole for orientation to reduce the risk of upside-down for cornea transplant in Hong Kong since Oct 2021. With the goal of maximizing the utilization of single donor corneal tissue for two patients needed for Anterior Lamellar Keratoplasty (ALK) and DMEK, HAEB started to provide bubble-assisted stamping on DMEK grafts without no stromal-hole for clinical use since Feb 2023.
Objectives :
Modify the stamping method to obtain DMEK graft without stromal-hole in Hong Kong
Methodology :
The bubble-assisted stamping by S-marker was applied to the stromal surface of DMEK graft. A 27-gauge cannula was attached to a 1ml syringe filled with air to create a small air bubble at the edge of the folding endothelial interface. From Feb 2023 to Dec 2023, total 12 pieces of DMEK grafts were pre-stripped with bubble-assisted stamping successfully. Comparing with the 6 DMEK grafts with stromal-hole S-mark stamping for clinical use, the variables of donor’s age, time consumption (time used for preparation), endothelial cell loss (ECL), mode of maximum transplant zone, S-mark visibility and location (diameter inside the graft) were analyzed.
Result & Outcome :
The success rate of DMEK graft preparation with bubble-assisted stamping was in 100% (12/12) and all S marks were clearly shown on the day of surgery. There were no significant differences between stromal-hole method and bubble-assisted method in the donor’s age: 56.3 ± 5.4yrs vs 63.3 ± 8.5yrs (p=0.084), time consumption: 37.5±4.2mins vs 33.6±9.5mins (p=0.353), average ECL: 0.41±2.45% vs 2.05±7.24% (p=0.602), the location of S-mark (diameter inside the graft): 6.0±1.8mm vs 6.4±1.6mm (p=0.658). Mode of maximum transplant zone of the two methods were 9.5mm.
In summary, there was no significant increase in ECL by this modified method in DMEK graft preparation compared with the stromal-hole method. We found that there was a decreasing trend in the time consumed by the bubble-assisted method, though there was no significant difference in two methods. HAEB provided the sufficient transplant zone (larger than 7.5mm) on the DMEK graft with clear S-mark in a proper location to surgeons that avoid the risk of upside-down during surgery. Maximizing the utilization of single donor corneal tissue for two patients (ALK and DMEK) may help to reduce the waiting time for cornea transplant due to tissue shortage.
