DSAEK GRAFTS WITH PARALLEL FACES : IS THE FUTURE? Luca Avoni IV ivis suite user meeting Innsbruck, 6 July 2013
Jul 02, 2015
DSAEK GRAFTS WITH PARALLEL FACES : IS THE FUTURE?
Luca AvoniIV ivis suite user meeting Innsbruck, 6 July 2013
Grafts with parallel faces
Purpose: avoid hyperopic shifts post DSAEK
obtain a thin graft with a uniform thickness from one side to the other in order to reduce the incidence of post-operative detachment
Retrospective observational study
15 donor corneas not suitable for transplantation, for morphological abnormalities or donor is not suitable for medical history, according to the following protocol :
1. Corneal pachymetry with corneal optical tomography
2. Setting pachymetry to a constant thickness of 550 um with excimer laser
3. Acquisition of corneal pachymetry
4. Cut of stromal flap with microkeratome for a thickness of 400 um
5. Acquisition of corneal pachymetry
6. Histological analysis of the cross section of stromal and endothelial flap
Retrospective observational study: Instruments
1.Optical tomography
2.Software for customized ablation.
3.Excimer laser.
4.Microkeratome
5.Ophthalmic microscope
Retrospective observational study
Software for the regularization of the corneal stroma to a desired thickness by a customized ablation with excimer laser
OBJECTIVES: Realization of stromal lenticule with uniform
thickness of 550 μ by a customized ablation with excimer laser
Realization of endothelial lenticule with uniform thickness of 150 µ
To evaluate the safety and effectiveness of this procedure
Step 1 Evaluation of the cornea by microscope according to the
traditional criteria of the EYE Bank (cell density, margins, morphology and mortality)
Morphological evaluation of corneal endotheliumDensity
Cell/mm2N =13
Mortality%
N =13
Mean
σ
1461.538
94.23
3.53%
0.07Interval 1000 ÷1900 0÷30
Morphological evaluation of corneal endothelium
MarginsN=13
Homogenous
CI 95%
3/1326.67%
(5.04 53.81 )
Partially HomogenousCI 95%
9/1366.67%
( 38.57 90.91)
IrregularCI 95%
1/1313.33 %
( 0.19 36.03)Morphological evaluation of corneal
endotheliumMorphology
N=13
Polymorphism
CI 95%
7/1346.67%
(19.22 74.87 )Moderate
PolymorphismCI 95%
6/13
53.33%(25.13 80.78 )
ITER
Step 2 Optical Corneal tomography with and study of the pachymetry map with high repeatability
ITER
Optical pachimetry examination of the corneaMin Pachimetry [ µ ]
N=13Max Pachimetry [ µ ]
N=13
Meanσ
612.0813.17
697,0821.78
Interval 568 ÷ 680 629 ÷ 767
STEP 3
Set up a Customized ablation to regularize the stroma to a constant residual thickness of 550
microns
ITER
STEP 4 Customized ablation with laser in order to obtain a regular stroma
lenticule of 550 microns thickness
ITER
STEP 5 Optical corneal tomography to assess the pachymetry
ITER
Optical Pachimetry after the laser regularization of the CorneaPachimetry [ µ ]
N=13Target
Left point Center point Right pointMeanσCI 95%
549.774.78
547.17 552.37
561.615.62
558.56 564,67
573,467,21
569.54 577.38550 ±25 µ
STEP 6Cut of the stromal flap with a microkeratome 400 micron-head to obtain a endothelial lenticule of 150 micron thickness.
ITER
STEP 7Pachymetry of endothelial lenticule. Thickness of stromal lenticule
is obtain by the difference between the pre-cut pachymetry and post-ablation pachymetry.
ITER
Optical Pachimetry after the 400 microns cut with microcheratomy of the endothelium lenticule
Pachimetry[ µ ] N=13
Target
150 ±50 µ
Left point Center point Right pointMean 142.1 156.05 170
σCI
95%1.82
141.11 143.093.202
154.31 157.795.56
166.98 173.02
Pachimetry of stromal lenticule after the 400 microns cut (Difference between optical corneal pachimetry and optical endothelium optical
pachimetry )
Pachimetry [ µ ] N=13
Target
Left point Center point Right pointMean 549.77 – 142.1 =
407.67561.61 - 156.05
= 405, 56573,46 - 156.05 =
417,41 400 ± 25 µ
Morphological evaluation of corneal endotheliumDensity [Cell/mm2]
N =13Mortality [ % ]
N =13Meanσ
1353.85122.69
16.68%0.48
Delta (Mean pre – Mean post)
Reduction 107.69
7.37 %
Increase13.15 %
Target Reduction < 10% Not Defined
Morphological evaluation of corneal endotheliumMorphology
N=13Delta (Mean pre – Mean post)
PolymorphicCI 95%
7/1346.67%
(19.22 74.87 )
No change
ModeratePolymorphicCI 95%
6/1353.33%
(25.13 80.78 )
No change
Morphological evaluation of corneal endotheliumMargins
N=13Delta (Mean pre – Mean post)
Homogenous CI 95%
3/1326.67%
(5.04 53.81 )
No change
Partially HomogenousCI 95%
9/1366.67%
( 38.57 90.91)
No change
IrregularCI 95%
1/1313.33 %
( 0.19 36.03)No change
ITERSTEP 8 Evaluation of the endothelial lenticule by microscope according to the traditional criteria of the EYE Bank (cell density, margins, morphology and mortality)
ITERSTEP 9 Histological evaluation of endothelial lenticule (thickness and morphology)and the stromal lenticule (thickness and morphology.)
Histological Thickness evaluated at 4 months after procedure executionEndothelium lenticule [ µ ]
N=13Stromal lenticule [ µ ]
N=13
Measured valueTarget
Measured valueTarget
Left point Center point Right point
150 ±50 µ
Left pointCenter point
Right point
400 ±25 µMean 139.4 161.7 204 508,7 522,7 540,1
σ
CI 95%
8.80134.62 144.18
14.89153.60 169.80
26.52189.58 218.42
23.67495.83 521,57
25.25508.97 536,43
18.28530.16 550.04
CONCLUSIONS
This clinical study showed that the procedure of regularization of the cornea thickness with the excimer laser IRES is effective and safe as shown in the following endpoints.
Fate clic per modificare il formato del testo della struttura
− Secondo livello struttura
Terzo livello struttura
− Quarto livello struttura
Quinto livello struttura
Sesto livello struttura
Settimo livello struttura
Ottavo livello struttura
Nono livello strutturaFare clic per modificare stili del testo dello schema Secondo livello
• Terzo livello Quarto livello
• Quinto livello
Histological evaluation
Paraffin embedding Staining with
hematoxylin and eosin
Scanner digital slides Measurement with
morphometro
Endothelial and stromal lenticules
CONCLUSIONS
Endpoint 1 –Stromal regularization:
The pachymetry after the customized ablation of the stromal lenticule has shown that the average thickness of 550 ± 25 micron has been achieved successfully
CONCLUSIONS
Endpoint 2 – Endothelial lenticule:
The pachymetry after the microkeratome cut of the endothelial lenticule has shown that the average thickness of 150 ± 50 micron has been achieved successfully
In addition to optical pachymetry, histological analysis, performed at the Pathology Department of Ospedale Maggiore-Bologna in October 2012, provided a further confirmation of the results.
CONCLUSIONS
Endpoint 3 – Stromal Lenticule:
The difference between the pachymetry performed before and after the customized ablation of the stromal lenticule has shown that the average thickness of 400 ± 50 micron has been achieved successfully.
The histological analysis has shown in this last case a stromal lenticule of 508,7 μm thickness of the left side, 522,7 μm of the center and 540,1 μm of the right side.
Probably, this inconsistency is due to the delay of more than four months from the date of execution of the procedure and the date of execution of the histological analysis.
Thank you