The Barron Radial Vacuum
Trephine is a second-generation
corneal trephine that is similar
in operation to the
Hessburg-Barron Vacuum Trephine.
Like the Hessburg-Barron
Vacuum Trephine, the Radial Vacuum
Trephine utilizes a vacuum to
hold the cornea against thetrephine during the trephination
of the cornea, and
needs no
auxiliary vacuum equipment.
It uses a simple hand-operated
syringe to create the vacuum.
The use of a stabilizing vacuum causes the cornea to be
held in its natural contour, thereby
producing a perpendicular incision
in the cornea to provide an
optimal recipient opening for
donor tissue. The
instrument is fabricated from
the highest grade stainless
steel and FDA-approved polymer
materials. It is delivered
in a transparent plastic tray
with a hermetically sealed Tyvek lid.
The Barron Radial Vacuum
Trephine was developed to
assist physicians in
the placement of corneal sutures. This is
accomplished through the
use of
16 small projections
in the vacuum chamber. The projections also
improve the
stabilization of the
cornea to eliminate
distortion of the cornea
during the trephination
cut.
When the trephine is
placed on the cornea and
vacuum is applied, these
projections make slight
indentations in the
cornea which can then be marked
with an accompanying
gentian violet ink pen
after the trephine is
removed from the eye.
With the suture points
evenly marked around the
cornea, the surgeon can
minimize astigmatism,
which is a common
side effect of
penetrating keratoplasty.
As with all BPI trephine
products, the blade of the
Barron Radial Vacuum Trephine is
fabricated from the hardest
stainless steel that is
available, and its manufacture
employs a proprietary,
multiple-stage honing of the
blade edge to give an
unsurpassed sharpness.
Some other manufacturers of
vacuum trephines construct their
instruments by bending
thin (0.1 mm thick) razor blades
into a cylinder, a process that
results in a non-circular
cylinder. Those thin
blades are also easily nicked,
bent, or chipped. BPI uses a
process that was developed to
yield quality blades that are
uniquely suited for corneal
surgery, and are precision
machined to yield a perfect
circular cylinder that is needed
for predictable surgical
results. The
blades in the BPI trephines are
a durable 0.3 mm thick, which
provides blades that are less
subject to accidental damage
that might be caused by the
surgeon or assistant during
preparation for the operation.
To facilitate optimal
location of the trephine
as it is positioned on
the patient's eye,
fine cross-hairs are
incorporated inside each trephine
blade. These help physicians to align
the trephine with the center of
the desired cut. The cross-hairs
are positioned in such a
way that they are as
close to the surface of
the cornea as possible
without contacting the
epithelium.
The blade is then
mounted in a
spoke adapter that allows the
blade to be precisely lowered at
a rate of 0.25 mm per each
revolution.
If you have Adobe
Flash installed as a
plug-in in your browser,
you can observe the
movement of the blade as
the spoke wheel is
rotated.
An introduction to the use of the Barron Radial Vacuum Trephine is shown in the Flash video segment on
the left. Just use
the video controls at
the bottom of the frame
to start the video.
If you don't have a
Flash Player installed
on your computer your
can alternatively
download an mpeg version
of the clip. Just click
on the thumbnail below
to download the 24MB
MPEG (.mp4) version.
The Barron Radial
Vacuum Trephines come in
11 sizes, with blades
ranging from 6.0 mm to
9.0 mm in diameter.
There are two families
of punches that can be
used in conjunction with
the Radial Vacuum
Trephines, the
Donor Cornea Punch
and the
Barron Vacuum Donor
Cornea Punch.
The punches are available in
0.25 mm diameter
increments to provide
flexibility in matching
donor tissue with the
incision made by the
trephine.
The Barron Radial Vacuum
Trephines are only
available through
Katena Products, Inc.
or one of their
authorized world-wide
distributors.
Please contact Katena to
place orders for the
Radial Vacuum Trephines.
