Download DESCEMET MEMBRANE ENDOTHELIAL KERATOPLASTY (DMEK

ARCH SOC ESP OFTALMOL 2009; 84: 237-244
ORIGINAL ARTICLE
DESCEMET MEMBRANE ENDOTHELIAL
KERATOPLASTY (DMEK): TWO-YEAR RESULTS
QUERATOPLASTIA ENDOTELIAL DE MEMBRANA DE
DESCEMET (DMEK): RESULTADOS A DOS AÑOS
DAPENA I1, HAM L2, LIE J3, VAN-DER-WEES J3, MELLES GRJ4
ABSTRACT
RESUMEN
Purpose: To report the two-year results of Descemet membrane endothelial keratoplasty (DMEK)
for managing corneal endothelial disorders.
Methods: Non-randomized prospective clinical
trial. A DMEK was performed in ten patients with
Fuchs’ endothelial dystrophy or bullous keratopathy. A 3.5 mm clear corneal incision was made
and «under air» DM was stripped off from the posterior stroma. A 9.0 mm diameter, organ cultured
donor DM roll was inserted into a recipient anterior
chamber, positioned into the posterior stroma and
secured by completely filling the anterior chamber
with air for 30 minutes.
Results: Three eyes showed complete detachment
of the tissue; this was managed by a secondary Descemet stripping endothelial keratoplasty procedure.
The remaining seven eyes had a best corrected
visual acuity of ≥ 0.7 in three eyes (43%) at one
month, in five eyes (71%) at six months, and in six
eyes (86%) at one and two years. At six months, the
endothelial cell density averaged 2039 (±373)
Objetivo: Describir los resultados, dos años después de realizar una queratoplastia endotelial de
membrana de Descemet (DMEK: Descemet membrane endothelial keratoplasty), para el tratamiento
de alteraciones del endotelio corneal.
Métodos: Estudio clínico prospectivo no randomizado. En 10 pacientes con distrofia endotelial de
Fuchs o queratopatía bullosa, se practicó una
DMEK. A través de una incisión de 3,5 mm en córnea clara, la membrana de Descemet (MD) del
receptor fue desprendida del estroma posterior en
presencia de aire. Un disco de 9 mm de diámetro
enrollado de MD donante preservada, fue insertado
en la cámara anterior del receptor, posicionado en
contacto con el estroma posterior corneal y asegurado en su posición mediante el llenado completo
de la cámara anterior con aire durante 30 minutos.
Resultados: Tres ojos mostraron un desprendimiento completo del tejido donante, por lo que fueron sometidos posteriormente a una queratoplastia
endotelial con «pelado» de la MD (DSEK: Desce-
Received: 15/10/08. Accepted: 24/4/09.
Netherlands Institute for Innovative Ocular Surgery. Rotterdam. The Netherlands.
1 Graduate in Medicine. Netherlands Institute for Innovative Ocular Surgery, Rotterdam, Holland. Melles Cornea Clinic Rotterdam, Rotterdam,
Holland.
2 Graduate in Health Sciences. Netherlands Institute for Innovative Ocular Surgery, Rotterdam, Holland. Melles Cornea Clinic Rotterdam,
Rotterdam, Holland.
3 Graduate in Health Sciences. Netherlands Institute for Innovative Ocular Surgery, Rotterdam, Holland. Amnitrans EyeBank Rotterdam,
Rotterdam, Holland.
4 Graduate in Medicine. Ph.D. in Medicine. Netherlands Institute for Innovative Ocular Surgery, Rotterdam, Holland. Melles Cornea Clinic
Rotterdam, Rotterdam, Holland. Amnitrans EyeBank Rotterdam, Rotterdam, Holland.
Correspondence:
Gerrit R.J. Melles, MD, PhD
Netherlands Institute for Innovative Ocular Surgery
Laan Op Zuid, 88
3071 AA Rotterdam
The Netherlands
E-mail: [email protected] / [email protected]
DAPENA I, et al.
cells/mm2 (n=7), at one year 1925 (±267) cells/mm2
(n=7) and at two years 1730 (±400) cells/mm2
(n=6).
Conclusions: DMEK may provide quick and
nearly complete visual rehabilitation. Since the
donor tissue can be stripped from donor corneoscleral rims, the procedure may be readily accessible to most corneal surgeons (Arch Soc Esp Oftalmol 2009; 84: 237-244).
Key words: Descemet membrane endothelial keratoplasty (DMEK), posterior lamellar keratoplasty,
corneal transplantation, Descemet membrane,
endothelium, surgical technique.
met stripping endothelial keratoplasty). En los siete
ojos restantes, se observó una agudeza visual mejor
corregida (AVMC) ≥ a 0,7 en 3 ojos (43%) en el primer mes, en 5 ojos (71%) a los seis meses, y en seis
ojos (86%) al primer y segundo años. A los seis
meses, la densidad celular endotelial media fue de
2039 (DS: 373) cél/mm2 (n=7), al año de 1925 (DS:
267 cél/mm2 (n=7) y a los 2 años de 1730 (DS: 400)
cél/mm2 (n=6).
Conclusión: DMEK podría proporcionar una recuperación rápida y casi completa de la visión. Debido a que el tejido donante puede ser obtenido a partir de anillos córneo-esclerales donantes, el procedimiento podría ser fácilmente accesible para la
mayoría de los cirujanos corneales.
Palabras clave: Queratoplastia endotelial de membrana de Descemet (DMEK), queratoplastia lamelar posterior, transplante corneal, membrana de
Descemet, endotelio, técnica quirúrgica.
INTRODUCTION
In recent years we have described several posterior lamellar keratoplasty procedures which allowed the substitution of the corneal endothelium
without incisions or sutures in the corneal surface
for managing Fuchs’ endothelial dystrophy and
aphakic or pseudophakic bullous keratopathy. In
1998 we described a technique in which a 7.5 mm
diameter posterior lamellar disc without sutures
could be transplanted through a 9.0 mm scleral incision with posterior suture (1-3). Since 2001, this
technique became known in the United States as
Deep Lamellar Endothelial Keratoplasty (DLEK)
(4). In 2000 we described a variant of the previous
technique that does not require sutures, in which a
disc-shaped posterior transplant with a diameter of
9.0-9.5 mm was inserted through a 5.0 mm self-sealable tunnelized scleral incision and deployed in the
anterior chamber (5). Since 2005, this technique has
become known in the United States as «small incision DLEK» (6). In 2003, we described the insertion of a donor posterior disc folded in combination
with a «descemetorrhesis» for removing the endothelial layer and its Descemet Membrane (DM)
from the receptor (7,8). At present, this technique is
known as Descemet’s stripping endothelial keratoplasty: DSEK) (9,10).
238
Even though the above techniques, designed and
developed by our institute, demonstrated their feasibility for transplanting a donor posterior corneal
disc without sutures, it could be expected that the
selective DM and endothelium transplant would
provide the best possible recovery of visual capacity in a corner with endothelial alteration (11-15).
This study describes the clinical results after two
years of an isolated DM transplant through a 3.5
mm self-sealing incision in a clear cornea, which
could be termed «Descemet Membrane Endothelial
Keratoplasty» (DMEK) (13-15).
SUBJECTS, MATERIAL AND
METHODS
The DMEK was performed in four males and five
females from 45 to 87 years of age with Fuchs’
endothelial dystrophy and/or bullous keratopathy
(table I). All the patients signed an informed consent
approved by the Institutional Review Board (IRB).
Donor tissue
In 10 donor ocular globes having less than 36
hours post mortem the corneal-scleral rings were
ARCH SOC ESP OFTALMOL 2009; 84: 237-244
Transplante de membrana de Descemet
Table I. Descemet Membrane Endothelial Keratoplasty (DMEK): 2-year results
Patient
Pre-surgery
# Age Sex RE/
(years)
LE
1 64
M
LE
2 61
F
3 87
Surgery
indication
Concomitant
disease
BCVA
Donor
Surgery
ECD
(cel/)
mm2
Complications
Post-surgery
BCVA
BMC
1 m 6 m 12 m 24 m
DCE
Observations
(cel/mm2)
6 m 12 m 24 m
0.3
2960
No
1.0 1.25 1.0
1.0
Adhered
RE
FED
None
(pseudophakic)
PPBK
None
1750 1678 1608 None
FC
2630
Complicated
graft
insertion
n.r. n.r.
n.r.
n.r.
n.r.
F
LE
PPBK
0.1
2460
No
0.25 0.4
0.4
n.d.
Adhered
4 86
F
RE
Pupil fixed and
RPE changes
after complicated
phako
FED
Superficial
(pseudophakic) stromal scar
0.3
2640
Vitreous pressure
n.r. n.r.
n.r.
n.r.
n.r.
5 72
M
RE
FED
Sub-epitelial central
(pseudophakic) corneal scar
0.1
2660
Excentric donor
pressure
0.5 0.6
0.7
0.7
6 60
M
LE
None
0.3
2470
No
1.0 1.0
1.0
1.0
7 76
F
LE
None
0.3
2520
No
0.6 0.8
1.0
0.9
Adhered
2180 2369 2289 None
8 59
9 74
M
F
RE
LE
None
None
0.8
0.3
2480
2640
No
No
1.0 1.0
0.6 0.7
1.0
0.8
1.0
1.0
Adhered
Adhered
1790 1743 1476 None
2730 2098 2034 None
10 45
F
RE
FED
(pseudophakic)
FED
(pseudophakic)
BK eci (phakic)
FED
(pseudophakic)
FED (phakic)
Adhered;
small
paracentral
DM roll
Adhered
2270 2100 1800 None
SEL
0.5
2640
Incomplete
donor
division
n.r. n.r.
n.r.
n.r.
n.r.
n.r.
n.r.
n.r.
1760 1675 n.d.
n.r.
DSEK without
complications
3 weeks
after initial
DMEK
1790 1812 1171 None
n.r.
n.r.
DSEK
without
complications
2 weeks after
initial DMEK
None
n.r.
n.r.
n.r.
DSEK without
complications
3 weeks
after initial
DMEK
ARMD = Age-Related Macular Degeneration; DSEK = Descemet stripping endothelial keratoplasty; FC = Finger Counting; n.r. = Not relevant; BCVA = Best Corrected Visual Acuity (Snellen); ECD
= Endothelial Cell Density; PPBK= Pseudo-Phakic Bullous Keratopathy; SEL = Systemic Erythematous Lupus; MD = Descemet Membrane; FED = Fuchs Endothelial Dystrophy; RPE = Retinal Pigmentary Epithelium; BMC = Biomicroscopy; BK eci = Bullous Keratopathy of unknown origin; m = Months; n.a. = Not available.
extracted and stored in a minimally modified essential medium (MMEM) at 31ºC for organ culture.
The mean age of donors was 71.3 years (SD: 6.1)
and the mean cellular endothelial count of the tissue
was 2614 (SD: 186) cel/mm 2 (Table).
After two weeks in culture medium without dextrane and with antibiotics at 31 ºC the morphology and
feasibility of the endothelial cells was assessed by
means of inverted microscopy (Axiovert 40. Zeiss,
Göttingen, Germany). Subsequently the corneal-scleral rings were assembled with the endothelial surface
upwards upon a custom-designed vacuum holding instrument and the DM was detached from the posterior
stroma using thin tweezers to obtain a 9.0 mm diameter endothelial single layer of DM. Due to the elastic
properties of Descemet’s membrane it rolled up spontaneously to form what is known as a «Descemetroll», with the endothelium facing outwards. Each
«Descemet-roll» was subsequently stored in a dextra-
ne-free organ culture medium with antibiotics for a
maximum period of one week awaiting transplant.
Surgery
An epithelial mark having a diameter of 9.0 mm
was made in the recipient eyes to circumscribe the
DM excision area. A 3.5 mm tunnelized incision
was made in the limbus, penetrating the anterior
chamber exactly at the limit of said mark. Utilizing
a custom-made scraper (Melles scraper, D. O. R. C.
International, Zuidland, The Netherlands) a circular
portion of DM was removed from the posterior stroma in the presence of air, carrying out a «descemetorrhexis» of 9.0 mm diameter and removing from
the eye the central portion thereof (7,8).
The donor «Descemet-roll» was dyed with a
0.06% tryphan blue solution (VisionBlue™, D. O.
ARCH SOC ESP OFTALMOL 2009; 84: 237-244
239
DAPENA I, et al.
R. C. International) and inserted in a custom-made
injector (Hippocratech, Rotterdam, The Netherlands) (11,12). Utilizing the injector, the donor
«Descemet-roll» was inserted in the anterior chamber and carefully extended over the surface of the
iris by indirect manipulation of the tissue with air
and a balanced saline solution. Subsequently, an air
bubble was injected under the donor DM to position
it and maintain the tissue in contact with the recipient posterior stroma (11,12). The anterior chamber was completely filled with air for 30 minutes
followed by an air-liquid replacement for pressurizing the eye.
(SD: 373) cell/mm2 (n=7) and at the first and second
year of 1925 (SD: 267) cell/mm2 (n=7) and 1730
(SD: 400) cell/mm2 respectively (fig. 1, Table I).
Initially, it was difficult to visualize the transplant
in the receiving eye. The confirmation that the
transplant was in the right position was obtained
observing its contour which showed a reflecting
brilliance on the donor DM and by means of mirror
microscopy which identified the paracentral endothelial donor cells. Some eyes exhibited small peripheral DM «tags», indicating the presence of DM
micro-detachments or folds in the external limit of
the transplant. With time, these peripheral tags stabilized and did not increase in size.
Endothelial assessment
DISCUSSION
The cellular feasibility of the donor endothelial
was assessed by means of inverted light microscopy
(Axiovert 40. Zeiss, Göttingen, Germany), taking
digital photographs (PixeLINK LP-A662, Zeiss,
Göttingen, Germany) after administering 1.8%
sucrose and dyeing with 0.04% blue tryphan (15-17).
The endothelium of the patients was photographed and assessed utilizing a non-contact autofocus
Topcon SP3000p mirror microscope (Topcon Corp,
Tokyo, Japan). The images of the central cornea
were manually analyzed and corrected, averaging
three measurements of the endothelial cellular density (15-17,19,20).
RESULTS
The first day post-op all the donor DMs exhibited
full adhesion to the posterior stroma of the receptor.
One week after the operation, the Descemet transplant retained its position in seven of the eyes, but
the three remaining eyes (cases 2, 4 and 10) exhibited a complete detachment of the donor membrane,
with the graft appearing rolled up and floating in
the anterior chamber. In these eyes a DSEK was
performed without complications two or three
weeks after the initial DMEK surgery.
In the seven eyes that exhibited complete adhesion of the graft we observed a best corrected visual
acuity (BCVA) ? to 0.7 in three eyes (43%) one
month after surgery, in five eyes (71%) six months
after surgery and in six eyes (86%) within the first
and second year (table I). At six months after surgery, the mean endothelial cell density was of 2039
240
In 1998 we described that the DM transplant was
technically possible in a cadaver human eye model
(11,12). At the time, obtaining a DM from a donor
corneal-scleral ring was seen as a challenge without
the support of an eye bank. As on some occasions
the peeling of the DM could be a challenge due to
the inadvertent tearing of the membrane, the donor
DM should preferably be prepared in the eye bank
prior to surgery instead of during the operation
itself. When the Amnitrans Eye Bank was established in Rotterdam (Amnitrans Eyebank Rotterdam)
in January 2004, all its facilities and logistics were
available for routine preparation of Descemet’s
membrane transplants, and the assessment of its
endothelial cell layer and the microbiological study
of the tissue to ensure its sterility. Since then, extensive lab studies were made to simplify the procedure (14-18). In addition, a number of technical modifications were designed for the surgical implantation of the donor DM layer, its manipulation in the
anterior chamber and its full adherence to the receiving posterior stroma. (Melles CRJ, unpublished
data, 2005) (14,15).
Recently, the possibility of transplanting an isolated DM was also demonstrated by Tappin and Pavel
utilizing different approaches. Tappin designed an
instrument for inserting a 7.5 mm diameter donor
DM in the anterior chamber through a sutured 8.0
mm incision (21). Pavel described the DM donor
tissue transplant linked to a stromal peripheral ring
to facilitate its handling (P. Studeny. Descemet’s
membrane with stromal hem transplantation. Winter ESCRS 2007). In this study, we transplanted
ARCH SOC ESP OFTALMOL 2009; 84: 237-244
Transplante de membrana de Descemet
Fig. 1: Slit lamp photograph of a transplanted cornea one year after performing DMEK (Case 6). A) notice the transparency of the transplanted cornea and the invisible anatomic interphase between the donor and host tissue. B) Notice the periphery of Descemet’s membrane signaled by the yellow arrow.
DM with endothelium through a small tunnelized
incision as previously described (11,12). Taking
into account the terms utilized for differentiating
different posterior lamellar keratoplasty procedures,
the instant procedure, i.e. the isolated donor DM
transplant carrying a feasible endothelial cell layer,
was initially termed DMEK.
The challenge in designing any posterior lamellar
keratoplasty procedure is to provide a sufficiently
high endothelial cellular density to obtain a longterm survival of the graft. In this study, both objective and subjective measures indicated that DMEK
could be potentially able to achieve cellular densities approaching 2000 cells /mm 2 in the mid-term,
comparable to those obtained after DLEK and
DSEK (6-19).
In comparison with the posterior lamellar keratoplasty techniques we designed in the past such as
DLEK and DSEK (14), DMEK could have five
main advantages: Firstly, this study suggests that
the visual recovery after DMEK could be much faster than after DLEK or DSEK because six out of
seven eyes with DMEK achieved a BCVA ≥ 0.5 one
month after surgery (table I). In addition, in the first
series described of 50 patients submitted to DMEK
due to Fuchs’ endothelial dystrophy, 95% exhibited
a BCVA ≥ 0.50.5, and more importantly 75% achieved a BCVA ≥ at 0.8 six months after surgery (22).
These numbers are in contrast with DLEK or DSEK
procedures which have demonstrated a mean BCVA
≥ 0.5 in an average time of six or more months
(6,9,23). The difference in the visual acuity recovery might suggest that the presence of donor posterior stroma in DLEK and DSEK is what primarily
determines the degree of visual recovery instead of
secondary changes or edema in the receiving corneal stroma, because in DMEK there is no transplanted donor posterior stroma.
However, in order to perform a DMEK it is
necessary to have an adequate visualization of the
anterior chamber due to the greater surgical complexity of the procedure. Therefore, in severely
unbalanced corneas, in the presence of training
devices for glaucoma, narrow anterior chamber or
low potential for visual rehabilitation, it would be
recommendable to perform a DSEK which is technically less challenging.
In second place, as DMEK could provide a nearperfect restoration of the corneal anatomy and a
better quality of the cornea, with this technique we
could expect a greater recovery of the visual capacity (11,12). Accordingly, in DMEK the end visual
ARCH SOC ESP OFTALMOL 2009; 84: 237-244
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DAPENA I, et al.
result might be limited only by the quality of the
anterior portion of the receiving cornea prior to surgery.
In Fuchs’ endothelial dystrophy it is not rare for
visual acuity to be unrelated to the visual symptoms
of the patient, and therefore in these cases VA
would not be a good indicator for surgery. An
example is case number 8 that exhibited a BCVA of
0.8 but a significantly decompensated cornea with
sub-epithelial secondary changes and a significant
alteration of sensitivity to contrast and color perception.
In the third place, in DMEK the diameter of the
graft can be of 9.0 up to 11.0 mm, which means that
a greater endothelial cell surface is transplanted
compared to DLEK (7.5 to 8.0 mm) or DSEK (8.5
to 9.5 mm). In our experience, even though the
correlation between the diameter of the graft and its
survival has not been demonstrated, we could
expect that a larger graft in DMEK will benefit the
long-term survival of the transplant.
Fourth, DMEK could demonstrate a better fulfillment of current requirements for anterior segment
of modern surgery because the donor DM can be
transplanted through a tunnelized incision in a clear cornea, which is widely utilized in phacoemulsification surgery and is known to induce a minimum
post-op astigmatism (17,24,25). Even though several instruments have been described for inserting a
donor DM (21,26,27), its utilization could Limit the
end diameter of the graft (6.0 to 7.5 mm), in addition to requiring a relatively large entry incision.
Fifth, in contrast with DLEK and DSEK, where
the majority of surgeons would require a microkeratome or femtosecond laser, in DMEK the donor
DM films can be «peeled» directly from a cornealscleral ring. With our technique for preparing 9.0
mm DM films from concave donor corneal-scleral
rings, the magnitude of the cellular lesion expressed
in the «percentage of damaged mean endothelial
surface area» is of 3.4% (11,12,18). Similar results
were found by Ignacio et al, who obtained Descemet transplants from convex rings (28), and Zhu et
al, who preserved rectangular films from concave
rings (29). It is important to emphasize that all of
the studies were made in preserved tissue, either in
cold storage or in organ culture medium. Accordingly, if it is possible to routinely obtain viable
grafts from preserve tissue, DMEK could be much
more accessible for the majority of corneal surgeons than DLEK or DSEK.
242
As with DSEK/DSAEK, the graft detachment
was the most frequent complication in DMEK. In
the first described series of 50 patients submitted to
DMEK due to Fuchs’ endothelial dystrophy, the
rate of detachment was 25%. However, when analyzing the last 25 patients who were intervened with
this procedure, the detachment rate went down to
12%. This reduction was related to the learning curve, changes in the surgical technique and in the
techniques utilized in the eye bank as well as to the
extension of the time for filling the anterior chamber with air in 45-60 minutes (22). In our experience, the most important factor for obtaining a complete adhesion of the donor tissue is to avoid the use
of hyaluronic acid throughout the procedure (14).
As with DSEK, all viscoelastics should be avoided
in DMEK because the detachment of the donor tissue is strongly correlated with their utilization (14).
In vitro experiments have proved that filling the
anterior chamber with air for at least 30 minutes is
essential to obtain a complete adhesion of the donor
tissue in DMEK whereas an air filling of only 15
minutes would be sufficient in DLEK and DSEK
(8,14).
Our experience with DMEK suggests that the
transplant of isolated donor DM carrying feasible
endothelium for treating alterations of the corneal
endothelium provides a near-perfect anatomic restoration and a high degree of visual rehabilitation.
As in DLEK and DSEK, the main drawback of the
procedure is the risk of detachment of the graft in
the early post-op (16). When the percentage of
detachments in DMEK can be reduced due to
improvements in the eye bank logistics and also in
the surgical technique, the project of posterior
lamellar keratoplasty should finally be completed.
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