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DMEK: Next Advances in Corneal Transplantation

Parag A. Majmudar, MD

Associate Professor, Dept. of OphthalmologyRush University Med. Center, Chicago IL

Chicago Cornea Consultants, Ltd.Chicago, IL

Paradigm Shift

• Over the past decade, there has been a shift away from penetrating keratoplasty to lamellar techniques

• Anterior lamellar techniques are providing visual results similar to penetrating keratoplasty without the risks of endothelial rejection

• Posterior lamellar techniques are providing much faster visual rehabiliation than penetrating keratoplasty

PK Surgery: Full Thickness Surgery

Recipient tissue removed

Donor tissue sutured into recipient

Smooth Surface with onlyendothelial disease

Full thickness block of tissue removed just to get to the endothelium

Central trephine cutmade

Sutures create anirregular surfacewith astigmatismand blurring

Penetrating Keratoplasty

• Replacement of a portion of the host cornea with a cornea from

– Another person (allograft)

– The fellow eye (autograft)

• Performed ~45,000 times/year in the U.S. 

The problem with traditional penetrating grafts:

Beautifully clear graft, 20/20 vision, minimal astigmatism.After sutures out at one year: MR: -8.00+5.00X70=20/20

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The Ideal Keratoplasty Procedure

• Better wound structure that requires less sutures or suture tension

• Less suture tension for less induced astigmatism

• Early suture removal for rapid visual rehabilitation

IntraLase Enabled Keratoplasty

IEK*: Femtosecond Laser Incisions for PKP

Goal: Improved Short‐term and Long‐term Post‐PKP Visual Recovery– Optimize graft/host matching– Enhanced wound edge for stability– Reduce suture tension and asymmetry– Minimize induced astigmatism – Enhance and expedite symmetric wound healing and early suture removal

– Induce less trauma to donor tissue Method– Laser incisions for precise tissue cuts and suture placement

* IntraLase Enabled Keratoplasty

IntraLase Enabled Keratoplasty

Example Pattern Combinations

TopHat Shape

• Provides large endothelial surface transplantation

Mushroom Shape

• Preserves more host endothelium

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ZigZag Shape

• Hermetic wound seal

• Angled edge provides smooth transition between host and donor

IntraLase Advanced Keratoplasty

The Zig-Zag shaped incision has shown a smooth corneal contour immediately after surgery with less distortion of the corneal optics and less astigmatism.

Farid M, Kim M, Steinert R. Results of Penetrating Kertoplasty Performed with a Femtosecond Laser Zigzag Incision: Initial Report. Ophthalmology 2007,;114:2208-2212.

Slitlamp

1 week

3 months

6 months

Astigmatism

Typical 1 yr post‐op result withstandard trephine cut PKP =          8 diopters of astigmatism

IntraLase Advanced Keratoplasty

at 3 months post-op = ½ diopter of astigmatism

* No Alignment Incision used

Severe Complications of Penetrating Keratoplasty: Suture Problems and Wound Healing Problems

Endophthalmitis:From retained suture fragment

Expulsive Hemorrhage:From mild blunt trauma five years after PK

Besides the common problems of high astigmatism and irregular astigmatism in standard PK…

Anterior Lamellar (Partial‐Thickness) Surgery

Recipient tissue removed (leaving Descemet’s and

endothelium)

Donor tissue sutured into recipient

Anterior Scar

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Posterior Lamellar (Partial‐Thickness) Surgery: DSAEK

Recipient tissue removed

Donor stroma and endothelium

Endothelial disease Central Endothelium RemovedEndothelium replaced

While preserving curvature

Posterior Lamellar (Partial‐Thickness) Surgery: DMEK

Donor endothelium

Endothelial disease Central Endothelium RemovedEndothelium replacedWhile preserving curvature

Most Common Reasons for Corneal Transplantation in the U.S.

Problems with the endothelium with swelling:

•Fuchs’ corneal dystrophy

•Pseudophakic Bullous Keratopathy

•Failed Corneal Transplant with Failed Endothelium

Problems with shape or scarring:

•Keratoconus

•Corneal Scars

•Other

INDICATIONS for EK

FuchsPBK/ABKPPMDCHEDTrauma (forceps delivery) ICE

Normal Endothelial Mosaic

BS – Pre-Op

Fuch’s Dystrophy Endothelial Cell Count: 545

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Emerging Trends

• Over the past decade, the approach to correction of primary endothelial disorders has been shifting away from penetrating surgery to lamellar (endothelial) keratoplasty (DSAEK, now DMEK)

Advantages of Endothelial Transplantation

Less astigmatism (no sutures)Faster visual recoveryLess anesthesia (topical vs. general)Stronger wound integrity (3-4 mm incision

vs. 360 degree circumferential incision)Possibly less risk of rejection (?) – less

donor tissue may mean lower antigenic load

Disadvantages of Endothelial Transplantation

No sutures (!) to hold graft in position –Graft dislocationPrice: 50% in 1st 10 cases, 13% in next

126, 6% in next 6 Terry: 3% in 100 consecutive cases

and 0% in next 100Steep learning curvePresence of optical interface between

donor and host results in minor, usually-well-tolerated optical degradation

Solution to Problems with P.K.

Eliminate corneal sutures:No suture problems

Eliminate corneal surface incisions:

Faster wound healing, smoothertopography, stronger and more stable eye.

The Revolution in Corneal Transplantation: 

Selective Endothelial Replacement

From DLEK to DSAEK to DMEK

The evolution of Endothelial Keratoplasty

DLEK: Hand dissected donorplaced in a hand resected bed

DSAEK: Microkeratome donorplaced on a smooth stripped surface

DMEK: Stripped Descemet’splaced on a smooth stripped surface

DMAEK: A DMEK with peripheralstroma to improve adhesion and handling

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DLEK Surgical Technique

Recipient tissue removed

Donor tissue placed into recipient

Corneoscleral incision, deep corneal pocket, and endothelium excised

Endothelium from posteriorstromal disc removed from pocket

Endothelium replaced without sutures, Surface topography with minimal change Diagram courtesy of

Dr. Ayad Farjo

Results with DLEK

• Patient recovered best vision in a matter of 2 monthsinstead of two years with PK

• No significant astigmatism induced so no patients needed to wear a GPCL for vision

• The QUALITY of vision was SO much better with DLEK compared to PK

• Vastly more patients had better vision without glassesor contacts with DLEK than with PK

• Rejection rate cut in half to about 9%

• Endothelial cell loss over time about equal to PK

But DLEK never became popular because:

• Downside: Very Difficult surgery to perform for most surgeons

• Downside: Most pts got to 2040 or 20/30 vision but few to 20/20

• Billing and reimbursement was difficult for DLEK

In 2003, Gerrit Melles designed DSEK/DSAEK surgery

• Surgery was now easier than DLEK

• Two eye banks in the U.S. (Lions Eye Bank of Oregon and North Carolina Eye Bank) learned to “pre‐cut” donor tissue for transplantation, eliminating the risk to surgeons of this step of surgery

Descemet’s Stripping Endothelial Keratoplasty (DSEK): Surgical Technique of stripping recipient descemets

Corneoscleral incision and endothelium stripped from posterior cornea

Endothelium replaced without sutures (endothelial cell pump

dependent mechanism), and surface topography with

minimal change

Donor posterior stroma and endothelium added onto back surface of recipient cornea, adding tissue thickness

(Diagram Courtesy of Dr. Ayad Farjo) Results with DSEK/DSAEK• Patient recovered best vision in a matter of 1 month instead of 2 or 3 months with DLEK

• Astigmatism and rejection rate about the same as DLEK

• Endothelial cell loss over time now BETTER than PK or DLEK

• Visual results: Vision better quality than DLEK and more patients getting 20/25 or better

• BIG upside: Surgery much easier to perform• BIG upside: Eye Bank now pre‐cutting tissue 

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What else do we know about DSAEK?Most any case of endo failure can be treated successfully with DSAEK

EK under PK for old RKEK under an old RK

EK for CHED in a 7 year oldEK over a Phakic Artisan AC IOL for PBK

First successful DSAEK in CHED Eyes in the United States: Devers(Long term follow‐up)

Pre‐op: CHED in 7 y/o girlVa cc = 20/200

Post‐op at 3 years:Va cc = 20/30+

Goshe JM, Li JY, Terry MA. Successful DSAEK for congenital hereditaryendothelial dystrophy in a pediatric patient.Int Ophthalmol. 2012 Feb; 32(1): 61-6.

Complications of DSAEK

Graft slid inferiorly

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Safety and Outcomes

Graft dislocations: 14%

Endo rejections: 10%

Primary graft failure: 5%

Iatrogenic glaucoma: 3%

Endo cell loss @ 6 months: 37%

Endo cell loss @ 12 months: 42%*

(Lee, et al. Ophthalmology Sept 2009)

Clear graft at 1 week – note interface

Video: Majmudar Suture Technique for DSAEK

Edematous but attached graft with 50% air bubble

Clear cornea @ 3 mos

Retrospective Contralateral Study Comparing DSAEK with PK (Cornea, June 2009)

Visual Recovery DSAEK 1.5 wks vs 5.3 wks Stable refraction DSAEK 3.7 wks vs 13.5 mos DSAEK less pain DSAEK sharper vision DSAEK less cylinder DSAEK better low contrast acuity DSAEK fewer HOAs!

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Transitioning to DMEK

Primary reasons for learning DMEK

Represents exact anatomic replacement EK   

Better visual results than DSAEK

Faster visual recovery than DSAEK

Has a lower rejection rate than DSAEK (<1% in first two years)

Popularity of DMEK in the U.S.

• Total EK procedures in U.S. in 2012:

23,049

• Total DSAEK cases: 22,301

• Total DMEK cases: 748 

EBAA MAB Statistics and Data Report 2012

Primary reasons surgeons are hesitant to learn DMEK

• Procedure is too hard and takes too long

• Stripping the donor tissue in the O.R. risks tearing it, cancelling the case, and still being stuck with a $3,600 invoice

• The re‐bubble rate and primary graft failure rate is much higher in DMEK than DSAEK, even in the hands of experts

• My patients are already happy with DSAEK, so why change?

Terry MA. Endothelial Keratoplasty: Why aren’t we all doing DMEK? Cornea 2012; 31(5): 469-71

DMEK: Yoeruek Tap TechniqueNo anterior bubble, shallow anterior chamber, finger pressure to globe 

(surgeon: M. Straiko)

An Easier and Faster Way of Unfolding the DMEK Tissue

DMEK : Yoeruek techniqueSurgeon: M.Straiko ‐ 9 Feb 2012 – First DMEK for surgeon 

3 weeks post‐op: Va = 20/20+1

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Tissue injected through 3.0 mm clear corneal incision Wound sutured and graft “flipped” for orientation and unfolding

Injection of SF6

One Day Post Op 6 days Post Op: PersistentGas Bubble to maintain supportof edges of Graft

Two Weeks Post Op: Va sc = 20/30+3 with Toric IOL

DSAEK v. DMEKMy first DMEK patients

Parag A. Majmudar, MD

Photos courtesy of Charles A. Faron, OD

DSAEK v. DMEKOD             OS

Acuity @ 3 weeks20/200 UCVA               20/80 BCVA

Acuity @ 3 weeks20/40+ UCVA 20/30 BCVA

Same Patient

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DSAEK GRAFT @ 3 yearsUDVA = 20/80, BCVA = 20/50

Pachy 734

DMEK GRAFT @ 3 WEEKSUDVA = 20/40+, BCVA = 20/30

Pachy 603 UCVA at 4 mos OD (DSAEK)  = 20/40UCVA at 4 days OS (DMEK) = 20/40

DSAEK

DMEK @ 4 days

2nd patient – prior DSAEK OD, DMEK OS

DSAEK  DMEKDMEK @ 4 days post‐op

Video

Example of specular after SF gas (20% concentration): 29% cellloss at 6 weeks – good morphology The literature to date suggests:

• By eliminating the stromal interface between the donor and recipient tissues (DMEK) yields about one line better and faster vision than DSAEK with a much higher percentage of 20/20 eyes

• The Quality of vision is likely better with DMEK than DSAEK due to the elimination of posterior irregularities and less higher order aberrations.

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What has the literature taught us about the vision after EK?

The average vision level and quality has improved with each new method of EK due to the improvement of the stromal interface between the donor and the recipient:

• DLEK (rough stroma to rough stroma): 20/40‐

• DSEK (rough stroma to smooth): 20/40+

• DSAEK (smooth stroma to smooth): 20/30+

• DMEK (no stroma to smooth): 20/25+

DSAEK and DMEK in same pt

DMEK: Va = 20/20 at 2 months DSAEK: Va = 20/25 at 8 months

OD OS

DMEK and DSAEK in same pt

DMEK:OD  Phakic – 1 week DSAEK: OS Phakic – 6 months

Vision = 20/20 without glasses Vision = 20/25+ with hyperopic glasses

What about DMEK v “ultrathin” DSAEK?

• Sixteen patients identified with an ultrathin (< 100u) DSAEK in one eye and a DMEK in the other

• Mean BSCVA Vision at 6 months:

DMEK: 20/25+   DSAEK: 20/32

• Vision 20/20 or better:

DMEK: 31%       DSAEK: 13%

• 75% of patients preferred the vision of the DMEK eye over the DSAEK eye

• 12% patients felt there was no difference in vision between DMEK and ultrathin DSAEK

Cases that should NOT have DMEK

• Eyes with Tubes and Trabs

• Eyes with AC IOLs left in place

• Eyes with Aphakia

• Eyes with Pupils that cannot be constricted

• Eyes with prior vitrectomy

So every surgeon doing DMEK needs to keep their DSAEK skills sharp!

DMEK: 1 week post opTotal Corneal edema‐ Graft separation

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Essential device for postop DMEK evaluations

O.C.T. imaging of cornea

DMEK:Iatrogenic Graft Non‐adherence – Why?

DMEK:Iatrogenic Graft Non‐adherence –

DMEK Graft is Upside Down

Graft should be scrolled with the edges pointing UPWARD

How to avoid upside‐down grafts

• Observe graft orientation in glass tube first, then twist tube so injection of tissue in proper orientation

• When in doubt, deepen chamber and “swirl” graft with BSS to see how it settles and orients

• Verify with Moutsouris sign if any doubt

• Use slit beam device if available

Liarakos et al (Melles Group): Intraocular graft unfolding techniques6 in Descemet membrane endothelial keratoplasty (DMEK)Ophthalmology 2012

Moutsouris Sign to determine Orientation of Graft

Moutsouris Sign to determine Orientation of Graft

DMEK surgery – May 2012Mark A. Terry, M.D.

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Tips on Rebubbling in Clinic

• Only re‐bubble if greater than 30% of graft shows separation (Melles paper)

• If progressive separation or central bullae with discomfort – rebubble

• Rebubble from side OPPOSITE site of separation

• Rebubble in supine position, evacuate aqueous, inject full air bubble all in one step

Recent advance to Eye Bank Prep for DMEK

• A dry ink “S” can be stamped on the Descemet’s side of the pre‐stripped DMEK scroll to allow absolute certainty of graft orientation before, during and after DMEK surgery.

• Upside‐down DMEK grafts (a major cause of iatrogenic graft failure) can be eliminated.

S stamp prior to trephination of pre‐stripped tissue

S stamp prior to final stripping

S stamp prior to final unfolding:Beware – backwards – upsided down graft!!!! Tissue up – final confirmation of S

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High Mag Confirmation  Acknowledgments

• Special thanks to Dr. Mark Terry and Michael Straiko for sharing some of the data and images used in this presentation 

Thank You for Your Attention!