Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: Toronto Canalatome and Method for Dissection
and Removal of Juxtacanicular Meshwork in
Schlemm's Canal.
INVENTOR: Christoph Kranemann
COUNTRY: Canada
OWNER: Christoph Kranemann
COUNTRY: Canada
APPLICANT: Christoph Kranemann
COUNTRY: Canada
AGENTS: Du Vernet, Stewart
AVAILABILITY OF LICENCE: Yes
LANGUAGE OF FILING: English
ABSTRACT OF THE DISCLOSURE:
TORONTO CANALOTOME
Two (2) surgical methods and one ( 1 ) apparatus for use by ophthalmic
surgeons for relieving interocular pressure through the dissection and removal
of
juxtacanicular meshwork in Schlemm's Canal. The apparatus is comprised of a
surgical
knife consisting of an elongate handle and a head portion. The handle, is one
hundred
and fifteen ( 11 Smm) millimetres in length and ten ( l Omm) millimetres in
diameter, and
consists of two (2) parts; a portion for gripping, which has a serrated or
otherwise
roughlined surface and measures one hundred ( 1 OOmm) millimetres in length,
and ten
( 1 Omm) millimetres in diameter, and a tapered head portion which is fifteen
( 1 Smm)
millimetres in length and tapers down to two (2mm) millimetres in diameter.
The handle
may be stainless steel, titanium or titanium alloy. The end which is smallest
in diameter
has attached to it one end of a guide wire which may be made of stainless
steel, titanium
or plastic, and which has a diameter no greater than one hundred ( 100)
microns and a
length no greater than twenty (20mm) millimetres. The end of the wire which is
attached
to the handle is so attached by a weld. The other end of the guide wire is
attached to a
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2
blade. This blade may be made of stainless steel or artificial diamond and
measures no
larger than three hundred (300) microns in length and two hundred (200)
microns in
width. The wire is attached to the blade by means of glue. The tip of the
blade is shaped
into a hook with an angle of inclination of thirty (30°) degrees.
The first method of use is comprised of a conjunctival dissection of five
(Smm) millimetres horizontally in the supertemporal quadrant; a scleral
dissection of
three (3mm) millimetres in width and three (3mm) millimetres posterior to the
surgical
limbus; exposure of Schlemm's Canal on either end of the dissection; placement
of a
canalostomy cannula in the medial end of the dissection; introduction of the
apparatus in
the temporal end of Schlemm's canal; passage of the apparatus temporally for
ninety
(90°) degrees and turning of the blade of the apparatus towards the
anterior chamber;
retraction of the blade together with the juxtacanicular part of the
trabecular meshwork;
and suturing of the sclera.
The second method of use is comprised of a corneal incision in the
superotemporal quadrant three (3mm) millimetres anterior to the surgical
limbus to a
depth of five hundred and fifty (550) microns; posterior dissection using a
beveled
keratome; medical introduction of a canalostomy cannula ten ( 1 Ocm)
centimetres above
the level of the patient; temporal introduction and passage for ninety
(90°) degrees of the
apparatus, with the blade turned to face the anterior chamber and then
retracted removing
the juxtacanicular part of trabecular meshwork; and suturing of the cornea.
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FIELD OF THE INVENTION:
This invention relates to surgical knives, and is particularly concerned with
surgical knives for use by ophthalmic surgeons for relieving interocular
pressure through
the dissection and removal of juxtacanicular meshwork in Schlemm's Canal.
Remediation of such pressure requires removal of the aforementioned
meshwork, but because of the small space in which the surgeon has to
accomplish this
and the need to both cut and extract it is best that a single small instrument
accomplish
both tasks.
It is also important that such knife be slip-proof and comfortable to handle
in order to facilitate precise control of its blade and hook.
It is also important that such a knife be of sufficiently small dimension that
it can be turned within Schlemm's Canal to facilitate removal of the meshwork
therein
without damaging the canal itself.
It is also important that the blade of such a knife be guided to compensate
for the difficulty the surgeon may encounter in perceiving the blade's
destination.
It is also important for the blade of such a knife to be small enough to cut
only the outer meshwork, rather than cutting through all of the meshwork; the
latter
causes scarring and collapses the architecture of the meshwork while the
former
maintains the architecture of the meshwork.
This invention permits the user to conduct non-penetrating surgery and
thereby minimizes both the risks of serious complications heretofore typically
associated
with glaucoma surgery and the patient's recovery time. The invention
accomplishes
these things by permitting the user to maintain the shape of the eye, to
reduce the
occurrence of bleeding and infection, and to sustain the physiologic integrity
of the eye.
SUMMARY OF THE INVENTION:
The present invention provides a surgical knife and hook which is designed
to meet these requirements.
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In accordance with the present invention there is provided a surgical knife
consisting of an elongate handle and a head portion.
The handle, which is one hundred and fifteen ( 11 Smm) millimetres in
length and ten (lOmm) millimetres in diameter, consists of two (2) parts; a
portion for
gripping, which has a serrated or otherwise roughlined surface and measures
one hundred
( 1 OOmm) millimetres in length, and ten ( 1 Omm) millimetres in diameter, and
a tapered
portion which is fifteen ( 1 Smm) millimetres in length and tapers down to two
(2mm)
millimetres in diameter. The handle may be stainless steel, titanium or
titanium alloy.
The end which is smallest in diameter receives an artificial diamond or
stainless steel
blade measuring no larger than one hundred by fifty ( 100 x 50) microns, and
having a
hook at its end with an angle of inclination of thirty (30°) degrees.
Attached to the blade
is a guide wire which may be made of stainless steel, titanium or plastic,
having a
diameter no greater than one hundred ( 100) microns and a length no greater
than twenty
(20mm) millimetres. The blade is attached to the blade by means of a weld.
METHOD OF USE 1:
After routine preoperative preparation of the patient's eye a conjunctiva)
dissection is carried out for five (Smm) millimetres horizontally in the
superotemporal
quadrant. A sclera) dissection is initiated three (3mm) millimetres posterior
to the
surgical limbus with a width of three (3mm) millimetres. A five hundred and
fifty (550)
micron blade is used for the sclera) incision and a beveled keratome for the
forward
dissection. Upon reaching the level of the cornea, Schlemm's canal is exposed
on either
end of the dissection. A canalostomy cannula (Grieshaber US Patent No.
5,486,165 and
5,360,399) is placed in the medial end and connected to a bag of balanced salt
solution
placed ten ( 1 Ocm) centimetres above the level of the patient.
The glaucomatome is introduced in the temporal end into Schlemms canal,
passed temporally for ninety (90°) degrees and turned with the blade
pointing towards the
anterior chamber. The blade is then retracted, removing the juxtacanalicular
part of the
trabecular meshwork.
The sclera is the sutured with two by ten (2 x 10-0) Nylon sutures and the
conjunctiva is sutured with two by eight (2 x 8-0) Vicryl sutures.
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All instruments are removed and antibiotic drops instilled into the eye.
METHOD OF USE 2:
After routine preparation of the patient's eye a corneal incision is placed in
the superotemporal quadrant three (3mm) millimetres anterior to the surgical
limbus. An
incision depth of five hundred and fifty (550) microns is used. Using a
beveled
keratome, the dissection is carried postreiorly until Schlemm's canal is
reached.
Medially, a canalostomy cannula is introduced and connected to a bag of
balance salt
placed ten (lOcm) centimetres above the level of the patient. Temporally the
glaucomatome is introduced and passed for ninety (90°) degrees. The
blade is turned to
face the anterior chamber and is then retracted, removing the juxtacanalicular
part of
trabecular meshwork. The cornea is sutured watertight with two to four by ten
(2-4 x
10-0) Nylon sutures. All instruments are removed and antibiotic drops
instilled.
BRIEF DESCRIPTION OF THE DRAWING:
In order that the invention may be fully understood, one presently preferred
embodiment of surgical knife in accordance with the invention will now be
described by
way of example, and with reference to the accompanying drawing, in which
Figure 1 is a
general assembly view of the knife; together with a detail of the blade of the
knife.
DESCRIPTION OF THE PREFERRED EMBODIMENT:
Referring to the drawing, the surgical knife which is shown therein and
which is particularly suitable for the discretion and removal of
juxtacanicular meshwork
in Schlemm's Canal is made entirely of stainless steel, titanium or titanium
alloy. The
knife is comprised of a generally cylindrical body (a), which is one hundred
and fifteen
(115mm) millimetres long in total and consists of two (2) parts; a handle (b),
which is
one hundred (100mm) millimetres in diameter and which is serrated or otherwise
rough
lined on its entire surface, which is the gripping portion, and a tapered
portion (c); which
is fifteen ( 1 Smm) millimetres in length and gradually reduces in diameter to
ten ( 1 Omm)
millimetres, and which is smooth. The end which is smallest in diameter (d),
receives a
knife blade (e), which measures no larger than one hundred by fifty (100 x SO)
microns,
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and which has a hook at its end (t~, which has an angle of inclination of
thirty (30°)
degrees. The blade is attached to the end of the handle by means of welding
(g). The
blade may be made of artificial diamond or of stainless steel. Attached to the
blade is a
guide wire (h), which has a diameter no greater than one hundred ( 100)
microns and a
length no greater than twenty (20mm) millimetres. The guide wire is attached
to the
blade by means of glue (i).
DATED this ~ day of July, 2000.
CHRISTOPH KRANEMANN
by his Attorney for Property,
DU VERNET, STEWART
Barristers and Solicitors
3300 Bloor Street West
West Tower, Suite 750
Toronto, Ontario M8X 2X2
Christopher Du Vernet
Telephone: (416) 231-1668
Facsimile: (416) 234-0993
