Transcript The Evolution of Corneal Transplantation

Corneal Transplantation
PHRM-520,L.S.No-5.1
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Review of Corneal Anatomy
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Epithelium
Bowman’s layer
Stroma
Descemets
Endothelial layer
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Endothelial layer
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Born with approx 4200 cells/mm2
Cells have a pump mechanism for
removing fluid from the cornea
No ability to replicate
Cell death throughout life
Cells are easily injured
Normal adult count 2800 c/mm2
Gross corneal edema with vision
change if <800 cells/mm2
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Indications for Corneal
Transplantation
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Lack of corneal clarity (scar)
Corneal curvature abnormalities
(ectasia)
Corneal edema
Lack of corneal integrity
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Why Corneal Grafting?
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Corneal Opacity
Corneal Clouding
Corneal Ectasias
Corneal Edema
Fuchs Endothelial Dystrophy
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Corneal Opacity
Corneal scarring from
firework accident
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Corneal Clouding
Granular stromal dystrophy
Fungal keratitis
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Corneal Clouding
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Corneal Ectasias
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Keratoconus- progressive corneal thinning
and steepening. Presents in late teens
and causes astigmatism that may not be
correctable with glasses or rigid contact
lenses
Pellucid marginal degeneration
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Corneal Edema
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Pseudophakic bullous keratopathy (PBK) –
swelling related to endothelial dysfunction.
Common problem with early lens implants.
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Fuchs Endothelial Dystrophy
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Inherited condition- AD w/ variable penetrance.
Endothelial cells die at a faster rate due to corneal
guttata. Poor vision due to edema, or to glare
caused by the guttata.
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Fuchs
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Loss of corneal Integrity
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Corneal perforation or melt (infectious or
rheumatologic)
Infectious melt due to
wire injury
One month post-op PK
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History
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1906 – Dr. Eduard Konrad Zirm in Moravia
performed the first successful penetrating
keratoplasty (PK) on a farmer in Prague
who sustained bilateral alkali burns after
cleaning his chicken coop with lime.
Bilateral 5 mm grafts from a single donor
(11 yo boy who required enucleation)
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History
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Essential Principles (still in use)
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Donor must be human
Aseptic technique
No antiseptic agents should go on cornea
Protect graft w/ saline moistened gauze
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Limitations
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good understanding of corneal physiology
or immunology
fine sutures or operating microscope
pharmacologic ability to treat or prevent
rejection
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History
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Elschnig (Prague) 1920 report
first clinical series of corneal
transplants
Reported another series of
174- confirmed partial PK
better then total. 22%
success rate (graft clarity)
Filatov (Odessa) reported 800
grafts from 1922-1945,
started to use cadaver
corneas
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History
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Ramon Castroviejo
(New York) 1930’s
designed a square
graft “watermelon
plug” to have better
wound coaptation.
Improved suturing
and instrumentation.
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von Hippel
clockwork
trephine
(trephine: a surgical instrument for
cutting out circular sections)
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History
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1945 R. Townley Paton started the first Eye Bank in
NYC. Early tissue was acquired from prisoners
executed at Sing-Sing prison
A. Edward Maumenee at Wilmer Eye Hospital
advanced the field with his work in corneal
physiology and immunology.
Coincided w/ the advent of topical corticosteroids
which had a profound effect on modern corneal
transplantation
Surgical success was followed by optical success
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1950 to present
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Operating microscope
New trephines and laser trephination
New suture needles
Viscoelastics
Steroids and other immunomodulators
Better antibiotics
Eye Bank Association of America (1961)
Improved storage medium for donor
corneas
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Eye Bank Association of America
contraindications for donor corneas
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Death of unknown cause
Unknown central nervous system disease
Infections including HIV or hepatitis
Active ocular inflammation
Leukemia or lymphoma
Cancer in the eye
Congenital corneal dystrophies or ectasias (e.g.
keratoconus)
Prior refractive surgery (e.g. LASIK)
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Storage Media
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Optisol GS allows for
storage up to 10 days.
Allows surgery to be
scheduled electively
D to P (death to
preservation) preferably
less than 12 hours
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Types of Corneal Transplants
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Penetrating keratoplasty (PK)
Lamellar keratoplasty (LK)
 Anterior lamellar keratoplasty (ALK)
 Deep anterior lamellar keratoplasty
(DALK)
 Posterior lamellar keratoplasty (PLK)
 Endothelial keratoplasty (EK)
 Deep lamellar endothelial keratoplasty
(DLEK)
 Descemet’s stripping endothelial
keratoplasty (DSEK)
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PK Surgery: Full Thickness Surgery
Central trephine cut
made
Smooth Surface with only
endothelial disease
Recipient tissue
removed
Full thickness block
of tissue removed just
to get to the endothelium
Donor tissue
sutured into
recipient
Sutures create an
irregular surface
with astigmatism
and blurring
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PK instruments
 Trephine with
suction for host
cornea
Donor cornea punch 
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Penetrating
keratoplasty for
keratoconus
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Penetrating
keratoplasty
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Indications for corneal transplant
Indication
1970s (%) 1980s (%) 1990(%)
PBK
ABK
Fuchs
Keratoconus
Regrafts
Scars
Ulcers
Corneal dystrophy
Chemical Burn
Trauma
Interstitial keratitis
Congenital
Virus
Other
1.7
9.2
6.4
16.5
26.2
4.2
2.7
4.7
3.2
3.7
5.8
0.4
12.1
3.0
18.9
8.4
10.6
16.0
18.9
7.3
3.0
2.5
0.6
2.1
2.2
0.6
5.5
3.3
21.1
4.0
13.4
13.4
11.8
0.4
4.6
2.8
0.4
2.0
0.3
1.3
1.4
23.1
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Problems with PK:
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Unpredictable astigmatism and corneal
power
Infection
Ulceration
Vascularization
Rejection
Poor Wound Healing: Risk of Rupture
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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
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Deep Lamellar Endothelial Keratoplasty
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First described by Dr. Gerrit Melles- 1998
First done in the US by Mark Terry, M.D.
Terry has done> 250 between 2000-05
Terry has trained> 100 cornea specialists
to perform DLEK, and formed EKG
(Endothelial Keratoplasty Group)
Initially all procedures done under IRB
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DLEK Surgery: Split Thickness Surgery
to replace only the diseased tissue
Recipient tissue
removed
Scleral incision, deep
corneal pocket, and
endothelium trephined
with Terry Trephine
Just endothelium on posterior
stromal disc removed from pocket
Donor tissue
placed into
recipient
Endothelium replaced with no sutures, supported
by air bubble in anterior chamber.
Surface remains smooth with no astigmatism
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EK
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Large air bubble is left in
the eye at the end of
surgery to help support
the graft while adhering.
Patient is to be supine the
rest of the day and night
If the bubble is too big,
pupillary block glaucoma
can occur
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Advantages of EK over PK
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Faster visual recovery
Less postoperative astigmatism (confirmed by
corneal topography)
Stronger globe integrity due to lack of fullthickness corneal incision
No suture related infections
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Disadvantages of DLEK
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More time consuming and difficult procedure due to
lamellar dissection
Graft dislocation- 5-20% on post-op day 1
Not as many patients get to 20/20 as with PK; may be
interface problem
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DSEK- Descemets Stripping
Endothelial Keratoplasty
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2005 Price, Gorovoy- eliminated the recipient
dissection by just removing descemets
membrane and the endothelium
Surgeon still had to perform the lamellar
dissection on the donor. If it went badly, the
tissue was wasted.
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DSAEK
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Replaced donor dissection with a cut made by an
automated lamellar keratome (used for LASIK
refractive surgery)
Cut can be made by the surgeon or at the eye bank
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DSAEK at UVA
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We undertook an IRB approved prospective
study to look at the DSAEK procedure as
described by Terry (Ophthalmology 2008;
115:1179-1186)
Dr. Paul Phillips (previous resident at UVA and
Terry fellow 2007-2008) performed initial
procedures and taught LAO
Strictly followed the procedure
First case performed 9/16/09
All tissue was pre-cut at Portland Eye Bank
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DSAEK: Complications
Dislocation
Primary Graft Failure
Price
(n=200)
8%
2%
Mearza
(n=11)
83%
9%
Koenig
(n=34)
27%
9%
Terry
(n=200)
1.5%
0%
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Cases – J.S
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62 yo F w/ Fuchs
LAO did PK OD 8/03 – did “well”
20/40 -3.25+4.75x025 (unable to
tolerate RGP)
9/16/09 TCC Phaco/IOL and 8.0mm
DSAEK – PP
20/25 Va unaided at 1 month post-op
VERY HAPPY patient
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P.R.
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58 yo F w/ Fuchs
LAO did PK OS 5/05 – did “well”
20/30 +4.50+1.25x055
5/19/09 TCC Phaco/IOL and 8.0mm
DSAEK – LAO
20/20-1 unaided 1 month post-op
VERY HAPPY patient
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Summary
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Corneal transplantation has evolved
dramatically over the past century.
The most recent advances have allowed
the procedure to become less invasive and
more optically successful for the recipient,
but more challenging for the surgeon.
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Thank You
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