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Surgery in AMD
a mixture of the cellular concentrate and an agent able
to promote adhesion in the subretinal space and buffer-
ing using gas or silicone
(49)
. Although good tolerability
has been demonstrated for pigment cells in the subreti-
nal space, as well as absence of membrane recurrence,
the poor functional results obtained in most studies have
been attributed to several factors, including lack of differ-
entiation in pigment cell reproliferation, failure in adhe-
sion to Bruch’s membrane and failure to form a regular
pigment epithelial cell monolayer
(47-51)
. Also according to
other authors, the behavior of transplanted cells depends
essentially on the type of environment found at the seed-
ing location
(52)
.
In a continuous attempt to change this discouraging
framework, Peyman performed the first homologous
and autologous EPR-Bruch’s membrane transplants in
1991
(53)
. Later, Aylward et al., of the Moorfields Eye
Hospital, were the first team to describe the concept of
total patch translocation of the EPR-choroid complex to
the subfoveal area
(54)
. The patches collected in the macu-
lar area near the EPR lesion were small; in follow-up,
none of the nine transplant patients displayed any func-
tion after 5 years
(55)
. van Meurs in Rotterdam described a
modification to this technique in which a full-thickness
patch of retinal pigment epithelium-choroid of approxi-
mately 1,5x2mm is harvested from within a circular zone
isolated by heavy diathermia in the superior midperiph-
ery
(56)
. Subsequently, other groups have been publishing
small case series presenting not only expressive and sus-
tained improvement in visual acuity and reading ability
but also recovery of central fixation, evidence for graft
revascularization (also demonstrated histologically in
animals experiments) and a normal autofluorescence over
the patch in patients with exudative or dry AMD
(56-64)
.
3.3 Management of submacular haemorrhage: dis-
placement with or without r-TPA
In addition to having a poor prognosis, exudative
forms of AMD, which display a relevant haemorrhagic
component, are difficult to diagnose (concerning mem-
brane location and extension) and to treat
(65,66)
. In the era
of antiangiogenic agents, this is possibly the only form of
AMD for which surgery is indicated, with the main objec-
tives of avoiding damages caused by blood (mechanical,
metabolic and toxic damages to the photoreceptor-RPE
complex) and allowing subsequent treatment (laser or
PDT)
(37,67,68)
. As previously referred, blood was initially
removed by aspiration or mechanically extracting. On a
later date, Lewis was the first researcher to report the fibri-
nolysis properties of r-TPA, which make this agent use-
ful in removing blood clots
(38-40)
. A procedure involving
displacement of submacular blood by intravitreal injec-
tion of r-TPA and gas, followed by prone position, was
described for the first time by Herriot in 1997
(69)
. Blood
is normally displaced temporally or infero-temporally,
with a significant increase in visual acuity occurring
immediately after the aforementioned procedure, as
described in countless published outcomes. Duration
of haemorrhage has been pointed out by some authors
as the main predictive factor for the aforementioned
improvement
(70-76)
. The usefulness of intravitreal r-TPA
as an adjuvant to this technique has been questioned, not
only because r-TPA diffusion to the subretinal space has
not been proved in experimental studies, but also because
some studies demonstrated the success of pneumatic
displacement of subretinal blood without concomitant
injection of r-TPA
(75-77)
. Therefore, a hybrid technique
was introduced by Haupert in 2001, combining submac-
ular surgery with pneumatic displacement
(78)
. After a few
changes, this technique is currently used in some centers,
as described: pars plana vitrectomy, removal of the pos-
terior hyaloid, injection of r-TPA (12.5 μg/0.1 mL) into
the subretinal clot using a 39-gauge flexible transloca-
tion cannula and fluid-air exchange followed by prone
position. The advantage of this technique is its smaller
percentage of associated intra and post-operative com-
plications, which is probably due to the smaller extent of
tissue manipulation involved and consequent reduction
in retinal injury
(78,79)
.
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