Introduction. Donor tissue preparation for Descemet Membrane Endothelial ASCRS Aim of dissection. DMEK graft preparation

Transcription

1 Introduction Donor tissue preparation for Descemet Membrane Endothelial keratoplasty (DMEK) ASCRS Endothelial Keratoplasty DSAEK / DSEK DMEK Donor lamellae stroma + DM + endothelium DM + endothelium Graft thickness 250 µm 75 µm 20 µm The NIIOS Team DMEK graft preparation Aim of dissection To harvest a roll of DM carrying autologous endothelium for transplantation in DMEK Current criteria for using a donor cornea: Donor not < 40 years Cell count of 2300 cells/mm 2 pre-dmek preparation + Cornea DMEK graft Anterior remnant

2 DMEK dissection Relevant anatomy: I. Corneoscleral rim endothelial side up Equipment: Cornea holder Non toothed forceps Hockey stick blade McPherson forceps Punch (9.5mm) Petridish Trypan Blue Pipette Soft contact lens Scleral rim Cornea Uveal remnants Iris root Trabecular meshwork Schwalbe s line Relevant anatomy: II Detachment and stripping 1. Stain with trypan blue Trypan blue stained corneoscleral rim The iris root and Schwalbe s line straddle the trabecular meshwork Dissection just outside the trabecular meshwork 2. Start peripherally outside the trabecular meshwork 3. Push centrally to detach a small amount of DM Collagen fibers in the stroma circumferentially near the limbus and meridionally towards the centre* In the peripheral 1-2 mm there is stronger adhesion between DM and the stroma 4. Turn the cornea and repeat previous step till DM is detached for 360 and cleared over 2mm inwards *Meek et al. The organisation of collagen fibrils in the human corneal stroma: a synchrotron X-ray diffraction study. Current Eye Research,1987. Reprint from: Groeneveld-van Beek EA, et al. Standardized 'no-touch' donor tissue preparation for DALK and DMEK: harvesting undamaged anterior and posterior transplants from the same donor cornea. Acta Ophthalmol. 2013, with permission form John Wiley & Sons.

3 Detachment and stripping Harvesting the graft 5. Strip DM off with Mc Pherson forceps 6. Pull DM towards centrally from different angles 9. Trephine the central 9.5 mm on a soft contact lens 10. Remove the DM outer circle over Detach DM completely, keeping attached trabecular meshwork intact 8. Anterior part of the cornea is replaced by a soft contact lens 11. DMEK graft will form a roll spontaneously (endothelium is on the outside) Troubleshooting tears during preparation DM graft Results DMEK preparation Tear in periphery Don t panic: it is outside trephination area! >95% of DMEK preparations successful! Tear which continues to tear to central If tear is small: Try to chip it off to avoid further tearing If tear is near trephination area: Try to detach DM from stroma with hockeystick blade around and underneath tear, then continue further stripping If all of the above fails try to detach DM further down the rim and try to strip DM from there Tear Damaged endothelium

4 Standardized no touch technique for Descemet membrane endothelial keratoplasty (DMEK) ASCRS The NIIOS Team DSEK versus DMEK: Interface DMEK BCVA (6m): 20/40 ( 0.5) in 95% 20/25 ( 0.8) in 75% ECD (6m): ± 1800 cells/mm 2 Low-cost, high accessibility Interface after DSEK Interface after DMEK 1. Ham L et al. Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy. Review of the first 50 consecutive cases.eye Ham L et al. Visual rehabilitation rate after isolated Descemet membrane transplantation: Descemet membrane endothelial keratoplasty. Arch Ophthalmol Ham L et al. Endothelial cell density after Descemet membrane endothelial keratoplasty: 1- to 2-Year Follow-up. Am J Ophthalmol

5 DMEK Surgical technique Incisions and Descemetorhexis Jan;129(1):88-94, with permission of JAMA Ophthalmology DMEK roll Preparation of the graft Jan;129(1):88-94., with permission of JAMA Ophthalmology

6 Implantation Checking the orientation Moutsouris sign DMEK-roll Jan;129(1):88-94., with permission of JAMA Ophthalmology Jan;129(1):88-94, with permission of JAMA Ophthalmology Centering and unfolding Appositioning the graft - Corneal surface strokes - Air injected underneath - Rolling/enlarging air-bubble - Monitor presence of peripheric inward folds if so, flattened with: Bubble-bumping Jan;129(1):88-94., with permission of JAMA Ophthalmology Jan;129(1):88-94, with permission of JAMA Ophthalmology

7 Fixating the graft Complete air-fill of the AC min 30-50% air-fill left over Preoperative 6m after DMEK Jan;129(1):88-94, with permission of JAMA Ophthalmology Conclusions Standardized no touch procedure Feasible with proper training Accessible to most corneal surgeons Minimal costs Potentially: The fastest and most complete visual recovery Preferred treatment method endothelial disorders

8 Study Intraocular Graft Unfolding Purpose To define and evaluate various DM-graft unfolding techniques in DMEK Techniques in Descemet membrane endothelial keratoplasty (DMEK) ASCRS The NIIOS Team Methods Retrospective video analysis of 100 consecutive DMEK cases 6 months of follow up (BCVA, ECD, Complications) Unfolding methods were categorized into 4 basic techniques (1) Standardized no-touch technique using a double roll (2) Two cannulas parallel ( Dirisamer technique ) Carpet unrolling while fixating one graft edge A B A B C D C D Jan;129(1):88-94, with permission of JAMA Ophthalmology Reprinted from: Liarakos et al. Intraocular graft unfolding techniques in descemet membrane endothelial keratoplasty. JAMA Ophthalmol Jan;131(1):29-35, with permission of JAMA Ophthalmology.

9 (3) Air-bubble assisted unrolling ( Dapena maneuver ) (4) Single sliding cannula maneuver A B A B C D Reprinted from: Liarakos et al. Intraocular graft unfolding techniques in descemet membrane endothelial keratoplasty. JAMA Ophthalmol Jan;131(1):29-35, with permission of JAMA Ophthalmology. C D Reprinted from: Liarakos et al. Intraocular graft unfolding techniques in descemet membrane endothelial keratoplasty. JAMA Ophthalmol Jan;131(1):29-35, with permission of JAMA Ophthalmology. Combined unfolding techniques Results Technique 1: used in 73% of surgeries Combination of techniques: in 44% A B None of the techniques correlated with - BCVA (P=0.511) - ECD (P=0.408) - Postop. complication rate (P=0.540) C D Reprinted from: Liarakos et al. Intraocular graft unfolding techniques in descemet membrane endothelial keratoplasty. JAMA Ophthalmol Jan;131(1):29-35, with permission of JAMA Ophthalmology. Reprinted from: Liarakos et al. Intraocular graft unfolding techniques in descemet membrane endothelial keratoplasty. JAMA Ophthalmol Jan;131(1):29-35, with permission of JAMA Ophthalmology.

10 Conclusions A B DMEK may be facilitated by using controlled techniques for unfolding the DM-graft: 1. as stand-alone techniques OR 2. various combinations Choosing the most suitable technique will make the operation safer and easier C D Without compromising the result or affecting the final outcome Reprinted from: Liarakos et al. Intraocular graft unfolding techniques in descemet membrane endothelial keratoplasty. JAMA Ophthalmol Jan;131(1):29-35, with permission of JAMA Ophthalmology. Descemet membrane endothelial keratoplasty (DMEK): Clinical outcome ASCRS The NIIOS Team

11 Percentage of eyes Study Purpose Evaluation of the clinical outcomes of DMEK Results: VA Methods Retrospective evaluation of 300 consecutive DMEK eyes 1 month to 6 years of follow up (Visual outcome, ECD, Complications) Follow up (years) Fast and complete visual rehabilitation Vision remains stable in time Results: Refractive outcome Results: ECD Hyperopic shift of ~0.3D probably caused by post-op steepening of posterior cornea Refractive stability at 3 months after DMEK ECD decrease may be comparable to earlier EK-techniques After 6 months, ECD decrease may be less than after PK Reprinted from: van Dijk et al. Near complete visual recovery and refractive stability in modern corneal transplantation: Descemet membrane endothelial keratoplasty (DMEK). Cont Lens Anterior Eye Feb;36 (1): 13-21, with permission from Elsevier. Reprinted from : Baydoun et al. Endothelial Cell Density After Descemet Membrane Endothelial Keratoplasty: 1 to 5-Year Follow-up. Am J Opthalmol. 2012, with permission from Elsevier.

12 Results: Complications Conclusions Graft detachment (~10%) Primary graft failure (~1%) Late onset graft failure (<1%) Allograft rejection episode (~2%) Fast and often complete visual rehabilitation Fast stabilization of refraction with only small refractive shift ECD decrease comparable to earlier endothelial keratoplasty techniques Low complication rate