Rotational alignment of corneal endothelial grafts and risk of graft detachment after Descemet membrane endothelial keratoplasty: a double‐masked pseudo‐randomized study

Abstract

Purpose: The posterior cornea is rotationally asymmetric, and Descemet membrane endothelial keratoplasty (DMEK) grafts preferentially scroll vertically. This prospective study assessed whether graft attachment after DMEK differed depending on the rotational alignment of the donor graft in the recipient eye. Methods: Pseudo-randomization and blinding of the graft orientation in the recipient's eye were possible by procedural separation: (1) The eye bank recorded the position of an orientation marker in the donor cornea; (2) the surgeon preparing the DMEK graft recorded an upside-down marker relative to the eye bank marker; and (3) the surgeon assessed the position of the upside-down marker in the recipient after DMEK. Surgeons were masked towards the eye bank marker. Using mixed-effects models, we assessed graft attachment relative to the rotational alignment of the donor graft. Results: Postoperatively, the graft was not fully attached in 59 of 179 eyes (33%). A second air fill (rebubbling) was performed in 11%. The graft axis was in line with the recipient cornea axis in 40%, oblique in 28% and orthogonal in 32%. We did not detect an elevated risk of incomplete attachment (odds ratio [OR], 1.16; 95% CI, 0.61-2.20), risk of rebubbling (OR, 1.25; 95% CI, or larger areas of graft detachment in non-aligned grafts compared to aligned grafts. Conclusion: Rotational alignment was not strongly associated with the risk of incomplete graft attachment, although modestly elevated risks cannot be ruled out. Efforts are needed to reduce the need for rebubbling after DMEK and to identify modifiable risk factors for graft detachment.

Graft Detachment after Descemet Membrane Endothelial Keratoplasty with and without Cataract Surgery

“…Compared to clinical slit lamp-based experience, the median area of graft detachment at the first AS OCT (31%) may seem relatively large, which is fully expected as the neural network identifies graft detachments missed by corneal specialists on slit lamp exam. 13,16 Further, it quantifies depth (mainly flat) and location (mainly graft margins) of detachment. These measures contrast with the usual rules of thumb, such as one-third of area detached, which may not be nuanced enough as an indication for rebubbling.…”

“…24 DMEK and cataract surgery, if needed, were performed as described previously. 3,13 After cataract surgery, surgical iridectomy was performed in all eyes using a diamond blade and an iris forceps before stripping the host's Descemet membrane at the inferior cornea (5 surgeons) or at the 10 o' clock position (1 surgeon). Descemet's membrane was stripped completely under air within a marked area of the graft's diameter.…”

“…9,10 Whether the combination of DMEK with cataract surgery causes more or less graft detachment is incompletely understood. [11][12][13] The definition of graft detachment and the indication and timing for repeat injecting of air or gas (rebubbling) varies between providers. 2,14 Given the numerous definitions of detachment, the proportion of eyes with graft detachment ranges between 2% to 82% and the proportion of eyes requiring rebubbling ranges between 0% to 76%.…”

Three-Dimensional Map of Descemet Membrane Endothelial Keratoplasty Detachment

“…Application of the neural network may help to understand detachment patterns, within-eye variability in detachment over time, and their risk factors *Cornea specialists estimated the area of graft detachment in percent using slit-lamp biomicroscopy. 15 ultimately to guide clinical decision making regarding how to improve long-term graft survival. 31 Relevant questions for future studies include revisiting surgical and nonsurgical strategies for managing incomplete attachment.…”

“…All participants were enrolled in a prospective corneal endothelial transplantation study (German Clinical Trials Registry identifier, DRKS00020947). 14 , 15 Written consent was obtained from all patients. The study was approved by the institutional ethics committee at the Faculty of Medicine Freiburg and conformed to the tenets of the Declaration of Helsinki.…”