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DSAEK GRAFTS WITH PARALLEL FACES : IS THE FUTURE? Luca Avoni IV ivis suite user meeting Innsbruck, 6 July 2013
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DSAEK grafts with parallel faces

Jul 02, 2015

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Luca Avoni

DSAEK grafts with parallel faces: is the future?
IV Ivis Suite User Meeting in Innsbruck
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Page 1: DSAEK grafts with parallel faces

DSAEK GRAFTS WITH PARALLEL FACES : IS THE FUTURE?

Luca AvoniIV ivis suite user meeting Innsbruck, 6 July 2013

Page 2: DSAEK grafts with parallel faces

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

Page 3: DSAEK grafts with parallel faces

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

Page 4: DSAEK grafts with parallel faces

Retrospective observational study: Instruments

1.Optical tomography

2.Software for customized ablation.

3.Excimer laser.

4.Microkeratome

5.Ophthalmic microscope

Page 5: DSAEK grafts with parallel faces

Retrospective observational study

Software for the regularization of the corneal stroma to a desired thickness by a customized ablation with excimer laser

Page 6: DSAEK grafts with parallel faces

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

Page 7: DSAEK grafts with parallel faces

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

Page 8: DSAEK grafts with parallel faces

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

Page 9: DSAEK grafts with parallel faces

STEP 3

Set up a Customized ablation to regularize the stroma to a constant residual thickness of 550

microns

ITER

Page 10: DSAEK grafts with parallel faces

STEP 4 Customized ablation with laser in order to obtain a regular stroma

lenticule of 550 microns thickness

ITER

Page 11: DSAEK grafts with parallel faces

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

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STEP 6Cut of the stromal flap with a microkeratome 400 micron-head to obtain a endothelial lenticule of 150 micron thickness.

ITER

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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

Page 14: DSAEK grafts with parallel faces

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)

Page 15: DSAEK grafts with parallel faces

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

Page 16: DSAEK grafts with parallel faces

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.

Page 17: DSAEK grafts with parallel faces

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

Page 18: DSAEK grafts with parallel faces

Endothelial and stromal lenticules

Page 19: DSAEK grafts with parallel faces

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  

Page 20: DSAEK grafts with parallel faces

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.

 

Page 21: DSAEK grafts with parallel faces

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.

Page 22: DSAEK grafts with parallel faces

Thank you