U.S. patent application number 10/350317 was filed with the patent office on 2003-12-25 for inflatable device and method for treating glaucoma.
This patent application is currently assigned to GMP Vision Solutions, Inc.. Invention is credited to Brown, Reay H., Lynch, Mary G..
Application Number | 20030236484 10/350317 |
Document ID | / |
Family ID | 22447552 |
Filed Date | 2003-12-25 |
United States Patent
Application |
20030236484 |
Kind Code |
A1 |
Lynch, Mary G. ; et
al. |
December 25, 2003 |
Inflatable device and method for treating glaucoma
Abstract
Catheter devices and methods for treating glaucoma and other eye
diseases by expandable dilatation of Schlemm's canal and/or direct
injection of medications into Schlemm's canal.
Inventors: |
Lynch, Mary G.; (Atlanta,
GA) ; Brown, Reay H.; (Atlanta, GA) |
Correspondence
Address: |
SUTHERLAND ASBILL & BRENNAN LLP
999 PEACHTREE STREET, N.E.
ATLANTA
GA
30309
US
|
Assignee: |
GMP Vision Solutions, Inc.
|
Family ID: |
22447552 |
Appl. No.: |
10/350317 |
Filed: |
January 23, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10350317 |
Jan 23, 2003 |
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09558557 |
Apr 26, 2000 |
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6524275 |
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60131030 |
Apr 26, 1999 |
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Current U.S.
Class: |
604/8 ;
606/107 |
Current CPC
Class: |
A61F 2230/0008 20130101;
A61M 2210/0612 20130101; A61M 25/007 20130101; A61M 25/0074
20130101; A61F 9/0017 20130101; A61F 2230/0052 20130101; A61F
9/00781 20130101; A61F 2250/0067 20130101; A61M 25/0068
20130101 |
Class at
Publication: |
604/8 ;
606/107 |
International
Class: |
A61M 005/00; A61F
009/00 |
Claims
What is claimed is:
1. A catheter device comprising a proximal portion manually
controllable by a user, a distal portion sized and shaped for
circumferential insertion into a portion of Schlemm's canal, and an
inflation supply lumen extending from the proximal portion to the
distal portion, wherein the distal portion of the inflationary
lumen is expandable and moves between a first Schlemm's canal
insertion position and a second Schlemm's canal inflation position
when inflated.
2. The catheter device of claim 1, further comprising a guiding
lumen extending from the proximal portion to the distal portion,
wherein the guiding lumen contains a steerable guidewire for
directing the catheter device into a desired length of Schlemm's
canal.
3. The catheter device of claim 1, further comprising a medicament
delivery lumen extending from the proximal portion to the distal
portion, wherein the medicament delivery lumen has at least one
fenestration therein on the distal portion for the delivery of
medicaments into Schlemm's canal.
4. The catheter device of claim 1, wherein the distal portion has a
diameter of about 0.1 to 0.5 mm.
5. The catheter device of claim 1, wherein the distal portion has a
diameter of about 0.3 mm.
6. The catheter device of claim 1, wherein the distal portion has a
length of about 1.0 to 20.0 mm.
7. The catheter device of claim 1, wherein the distal portion has a
pre-formed curvature having a radius which approximates the radius
of Schlemm's canal of a human eye.
8. The catheter device of claim 1, wherein the distal portion has a
pre-formed curvature having a radius of between about 3 mm and 10
mm.
9. The catheter device of claim 1, wherein the distal portion has a
pre-formed curvature having a radius of about 6 mm.
10. A catheter device comprising a proximal portion manually
controllable by a user, a distal portion sized and shaped for
circumferential insertion into a portion of Schlemm's canal, and a
medicament delivery lumen extending from the proximal portion to
the distal portion, wherein the medicament delivery lumen has at
least one fenestration therein on the distal portion for the
delivery of medicaments into Schlemm's canal.
11. The catheter device of claim 10, further comprising a guiding
lumen extending from the proximal portion to the distal portion,
wherein the guiding lumen contains a steerable guidewire for
directing the catheter device into a desired length of Schlemm's
canal.
12. The catheter device of claim 10, further comprising an
inflation supply lumen extending from the proximal portion to the
distal portion, wherein the distal portion of the inflation supply
lumen is expandable and moves between a first insertion position
and a second inflation position when inflated.
13. The catheter device of claim 10, wherein the distal portion has
a diameter of about 0.1 to 0.5 mm.
14. The catheter device of claim 10, wherein the distal portion has
a diameter of about 0.3 mm.
15. The catheter device of claim 10, wherein the distal portion has
a length of about 1.0 to 20.0 mm.
16. The catheter device of claim 10, wherein the distal portion has
a pre-formed curvature having a radius which approximates the
radius of Schlemm's canal of a human eye.
17. The catheter device of claim 10, wherein the distal portion has
a pre-formed curvature having a radius of between about 3 mm and 10
mm.
18. The catheter device of claim 10, wherein the distal portion has
a pre-formed curvature having a radius of about 6 mm.
19. A method for the surgical treatment of glaucoma and other
diseases, comprising inserting the catheter device of claim 1 into
Schlemm's canal and expanding the canal by inflating the distal
portion of the inflation lumen.
20. A method for the surgical treatment of glaucoma and other
diseases, comprising inserting the catheter device of claim 10 into
Schlemm's canal and delivering a medicament into the canal through
the at least one fenestration in the distal portion of the
medicament delivery lumen.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/131,030, filed Apr. 26, 1999.
TECHNICAL FIELD
[0002] The present invention is generally directed to a surgical
treatment for glaucoma and other eye diseases and relates more
particularly to an inflatable device and method for use in
ophthalmic surgery to mechanically dilate Schlemm's canal in the
eye and/or instill medications within Schlemm's canal for direct
action upon the canal, the trabecular meshwork, and adjacent
tissues.
BACKGROUND OF THE INVENTION
[0003] Glaucoma is a significant public health problem, because
glaucoma is a major cause of blindness. The blindness that results
from glaucoma involves both central and peripheral vision and has a
major impact on an individual's ability to lead an independent
life.
[0004] Glaucoma is an optic neuropathy (a disorder of the optic
nerve) that usually occurs in the setting of an elevated
intraocular pressure. The pressure within the eye increases and
this is associated with changes in the appearance ("cupping") and
function ("blind spots" in the visual field) of the optic nerve. If
the pressure remains high enough for a long enough period of time,
total vision loss occurs. High pressure develops in an eye because
of an internal fluid imbalance.
[0005] The eye is a hollow structure that contains a clear fluid
called "aqueous humor." Aqueous humor is formed in the posterior
chamber of the eye by the ciliary body at a rate of about 2.5
microliters per minute. The fluid, which is made at a fairly
constant rate, then passes around the lens, through the pupillary
opening in the iris and into the anterior chamber of the eye. Once
in the anterior chamber, the fluid drains out of the eye through
two different routes. In the "uveoscleral" route, the fluid
percolates between muscle fibers of the ciliary body. This route
accounts for ten percent of the aqueous outflow. The primary
pathway for aqueous outflow is through the "canalicular" route that
involves the trabecular meshwork and Schlemm's canal.
[0006] The trabecular meshwork and Schlemm's canal are located at
the junction between the iris and the sclera. This junction or
corner is called "the angle." The trabecular meshwork is a
wedge-shaped structure that runs around the circumference of the
eye. It is composed of collagen beams arranged in a
three-dimensional sieve-like structure. The beams are lined with a
monolayer of cells called trabecular cells. The spaces between the
collagen beams are filled with an extracellular substance that is
produced by the trabecular cells. These cells also produce enzymes
that degrade the extracellular material. Schlemm's canal is
adjacent to the trabecular meshwork. The outer wall of the
trabecular meshwork coincides with the inner wall of Schlemm's
canal. Schlemm's canal is a tube-like structure that runs around
the circumference of the cornea. In human adults, Schlemm's canal
is believed to be divided by septa into a series of autonomous,
dead-end canals.
[0007] The aqueous fluid travels through the spaces between the
trabecular beams, across the inner wall of Schlemm's canal into the
canal, through a series of collecting channels that drain from
Schlemm's canal and into the episcleral venous system. In a normal
situation, aqueous production is equal to aqueous outflow and
intraocular pressure remains fairly constant in the 15 to 21 mm Hg
range. In glaucoma, the resistance through the canalicular outflow
system is abnormally high.
[0008] In primary open angle glaucoma, which is the most common
form of glaucoma, the abnormal resistance is believed to be along
the outer aspect of trabecular meshwork and the inner wall of
Schlemm's canal. It is believed that an abnormal metabolism of the
trabecular cells leads to an excessive build up of extracellular
materials or a build up of abnormally "stiff" materials in this
area. Primary open angle glaucoma accounts for approximately
eighty-five percent of all glaucoma. Other forms of glaucoma (such
as angle closure glaucoma and secondary glaucomas) also involve
decreased outflow through the canalicular pathway but the increased
resistance is from other causes such as mechanical blockage,
inflammatory debris, cellular blockage, etc.
[0009] With the increased resistance, the aqueous fluid builds up
because it cannot exit fast enough. As the fluid builds up, the
intraocular pressure (IOP) within the eye increases. The increased
IOP may compromise the vascular supply to the optic nerve that
carries vision from the eye to the brain. Some optic nerves seem
more susceptible to IOP than other eyes. While research is
investigating ways to protect the nerve from an elevated pressure,
the only therapeutic approach currently available in glaucoma is to
reduce the intraocular pressure.
[0010] The clinical treatment of glaucoma is approached in a
step-wise fashion. Medication often is the first treatment option.
Administered either topically or orally, these medications work to
either reduce aqueous production or they act to increase outflow.
Currently available medications have many serious side effects
including: congestive heart failure, respiratory distress,
hypertension, depression, renal stones, aplastic anemia, sexual
dysfunction and death. Compliance with medication is a major
problem, with estimates that over half of glaucoma patients do not
follow their correct dosing schedules.
[0011] When medication fails to adequately reduce the pressure,
laser trabeculoplasty often is performed. In laser trabeculoplasty,
thermal energy from a laser is applied to a number of noncontiguous
spots in the trabecular meshwork. It is believed that the laser
energy stimulates the metabolism of the trabecular cells in some
way, and changes the extracellular material in the trabecular
meshwork. In approximately eighty percent of patients, aqueous
outflow is enhanced and IOP decreases. However, the effect often is
not long lasting and fifty percent of patients develop an elevated
pressure within five years. The laser surgery is not usually
repeatable. In addition, laser trabeculoplasty is not an effective
treatment for primary open angle glaucoma in patients less than
fifty years of age, nor is it effective for angle closure glaucoma
and many secondary glaucomas.
[0012] If laser trabeculoplasty does not reduce the pressure
enough, then filtering surgery is performed. With filtering
surgery, a hole is made in the sclera and angle region. This hole
allows the aqueous fluid to leave the eye through an alternate
route.
[0013] The most commonly performed filtering procedure is a
trabeculectomy. In a trabeculectomy, a posterior incision is made
in the conjunctiva, the transparent tissue that covers the sclera.
The conjunctiva is rolled forward, exposing the sclera at the
limbus. A partial thickness scleral flap is made and dissected
half-thickness into the cornea. The anterior chamber is entered
beneath the scleral flap and a section of deep sclera and
trabecular meshwork is excised. The scleral flap is loosely sewn
back into place. The conjunctival incision is tightly closed.
Post-operatively, the aqueous fluid passes through the hole,
beneath the scleral flap and collects in an elevated space beneath
the conjunctiva. The fluid then is either absorbed through blood
vessels in the conjunctiva or traverses across the conjunctiva into
the tear film.
[0014] Trabeculectomy is associated with many problems. Fibroblasts
that are present in the episclera proliferate and migrate and can
scar down the scleral flap. Failure from scarring may occur,
particularly in children and young adults. Of eyes that have an
initially successful trabeculectomy, eighty percent will fail from
scarring within three to five years after surgery. To minimize
fibrosis, surgeons now are applying antifibrotic agents such as
mitomycin C (MMC) and 5-fluorouracil (5-FU) to the scleral flap at
the time of surgery. The use of these agents has increased the
success rate of trabeculectomy but also has increased the
prevalence of hypotony. Hypotony is a problem that develops when
aqueous flows out of the eye too fast. The eye pressure drops too
low (usually less than 6.0 mmHg); the structure of the eye
collapses and vision decreases.
[0015] An alternative surgical method for glaucoma management can
be directed more specifally at Schlemm's canal. U.S. Pat. No.
5,360,399 teaches the placement of part of a plastic or steel tube
into Schlemm's canal with injection of a viscous material through
holes in the tube to hydraulically hydrodissect the trabecular
meshwork. However, the '399 device provides little or no option for
the distance of the hydrodissection within the length of Schlemm's
canal, nor suggests a means for dilating the canal to facilitate
the natural drainage therefrom.
[0016] A need exists, then, for a system that would allow for
precise dilation and expansion of Schlemm's canal along any portion
thereof. A need exists for the selective, direct delivery of
therapeutic agents into Schlemm's canal that provides more
effective control of glaucoma with fewer systemic complications
than with existing medication delivery alternatives. In addition, a
more physiologic system is needed to enhance the drainage of
aqueous fluid into Schlemm's canal from the anterior chamber angle.
Enhancing aqueous flow directly into Schlemm's canal would minimize
scarring since the angle region is populated with a single line of
nonproliferating trabecular cells. Enhancing aqueous flow directly
into Schlemm's canal and naturally therefrom into the collecting
channels would minimize hypotony since the canal is part of the
normal outflow system and is biologically engineered to handle the
normal volume of aqueous humor. Enhancing aqueous flow directly
into Schlemm's canal would eliminate complications such as
endophthalmitis, hypotony, and leaks.
SUMMARY OF THE INVENTION
[0017] The present invention is directed to a novel inflatable
catheter device and an associated method for the surgical
correction of glaucoma in which the inventive device is placed
within Schlemm's canal and the inflatable element of the device is
expanded to temporarily stretch and expand the lumen of the canal.
At that point, the inflatable element may be used to temporarily
occlude outflow through the canal, while physiologic material is
injected through another lumen of the device, thereby distending
the canal and expanding areas of stenosis within the canal. The
inflated element may be decompressed and removed after the desired
expansion is achieved, or the device may be extracted with the
inflatable component expanded, to further mechanically dilate the
passageway within Schlemm's canal.
[0018] The present invention may also be employed to inject various
medications directly within Schlemm's canal. Such medications may
include, but are not limited to, antifibrotics, antibiotics, and
other medications which may have direct effects within the internal
structures of Schlemm's canal, the trabecular meshwork, and other
tissues of the eye. The present invention may also be employed to
deploy various stents or shunts directly within Schlemm's canal to
help maintain patency within the canal following removal of the
inflatable device.
[0019] The inventive device and method described herein therefore
facilitates the normal physiologic pathway for drainage of aqueous
humor from the anterior chamber to Schlemm's canal and exiting to
the collecting channels, rather than shunting to the sclera or
another anatomic site as is done in most prior art devices. In
addition, the present invention provides a mechanism for the
delivery of devices or medications directly into Schlemm's canal
and the adjacent ophthalmic anatomy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an illustration showing an overall view of one
embodiment of the present invention, in which the inventive device
is comprised of a dual, concentric lumen catheter with an outer
lumen terminating in an inflatable sleeve, and an inner lumen which
protrudes distal to the inflatable sleeve and terminates in an open
tip. FIG. 1 further shows a guidewire which extends throughout the
length of said catheter.
[0021] FIG. 2 is an illustration showing a cross sectional view at
point A-A' as shown on FIG. 1 and detailing the concentric nature
of the two lumens within this embodiment of the present
invention.
[0022] FIG. 3 is an illustration showing a detail of the distal
portion of one embodiment of the present invention in which the
inventive catheter is configured with the inflatable sleeve
operated by the external lumen, and with the internal lumen
protruding distally to the inflatable sleeve and containing a
plurality of fenestrations before terminating in a blunted tip.
[0023] FIG. 4 is an illustration showing another possible
embodiment of the inventive catheter in which the inflatable sleeve
is operated by the internal lumen, and with the external lumen
extending to the origin of the inflatable sleeve and containing a
plurality of fenestrations.
[0024] FIG. 5 is an illustration showing the relevant anatomic
details of the human eye.
[0025] FIG. 6 is an illustration showing the anatomic relationships
of the surgical placement of an exemplary embodiment of the present
invention within Schlemm's canal.
[0026] FIG. 7 is a schematic illustration showing the effects on
Schlemm's canal (exaggerated for purposes of this illustration) of
injection of a medicament by one embodiment of the inventive
catheter.
[0027] FIG. 8 is a schematic illustration showing the effects on
Schlemm's canal (exaggerated for purposes of this illustration) of
injection of a medicament by one embodiment of the inventive
catheter.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0028] The present invention provides catheter devices for the
dilatation of Schlemm's canal of the eye by mechanically distending
a portion of the canal when inflated. The inflatable catheter
devices may also be used to provide a conduit capable of delivering
therapeutic and/or expansive medicaments injected therethrough into
Schlemm's canal. The inflatable catheter devices may also be used
to provide a delivery mechanism for stents, shunts and the like
into Schlemm's canal to maintain patency within the canal to
facilitate the natural drainage of aqueous humor. Furthermore,
optical fibers, cameras, temperature sensors, pressure sensors, and
any other probe or suitable useful device can be delivered to
within Schlemm's canal by the present invention.
[0029] The invention provides a catheter device comprising a
proximal portion manually controllable by a user, and a distal
portion shaped and sized for circumferential insertion into a
portion of Schlemm's canal. The device further comprises an
inflation supply lumen extending from the proximal portion to the
distal portion. The distal portion of the inflation supply lumen
can be constructed of a resilient, expandable material for radially
dilating a portion of Schlemm's canal when inflated. Inflation can
be achieved by gas or liquid injection into the proximal portion of
the inflation supply lumen, and can be carefully monitored for
volume and pressure so as to accurately expand the distal lumen of
the catheter device to the desired amount, Therefore, the distal
portion of the inflationary lumen can move between a first
insertion position and a second inflation position when inflated
via the proximal portion.
[0030] It has not been heretofore determined that Schlemm's canal
is patent throughout its circumference in normal individuals, as
opposed to being divided by septa into multiple dead end canals.
The invention utilizes this new knowledge to access Schlemm's canal
and to create and maintain patency within the canal with the
present devices.
[0031] The proximal portion of the catheter device is designed to
receive a connector for attachment of an inflation means, such as
an injection syringe or pump. The device can also comprise a
guiding lumen extending from the proximal portion to the distal
portion, wherein the guiding lumen contains a steerable guidewire
for directing the catheter device into a desired length of
Schlemm's canal.
[0032] In some embodiments, the catheter device can provide
medicinal compositions therethrough for deposit into Schlemm's
canal. This can be achieved by utilizing a single lumen with one or
more openings or fenestrations in the distal portion thereof. In
some cases, the delivery of a medicament may itself be an inert
material, such as a gel, to expand and dilate the canal
sufficiently, thereby providing a therapeutic effect.
Alternatively, the catheter device can have a separate medicament
delivery lumen and an inflation lumen, as described above. In
certain embodiments, the inflation lumen is concentrically located
at a site along the distal portion to provide occlusion of
Schlemm's canal either distally or proximally to the material
injected.
[0033] The present invention is directed to devices and surgical
methods for dilating Schlemm's canal and/or for delivering
topically active medications directly into Schlemm's canal
utilizing an inflatable device that is surgically inserted within
at least a portion of Schlemm's canal. The portion of the device
extending circumferentially into Schlemm's canal may be fashioned
from a flexible, biologically inert material. The distal portion of
the catheter device has a diameter approximately equal to that of
Schlemm's canal of a human eye. The external diameter of the distal
portion can be between about 0.1 and 0.5 mm, or preferably about
0.3 mm. The length of the distal portion can be between about 1.0
and 20 mm, or preferably about 10 mm. The distal portion of the
catheter device can have a pre-formed curve having a radius
approximately equal to that of Schlemm's canal. The radius of the
distal portion can be between about 3 and 10 mm, or preferably
about 6 mm.
[0034] One embodiment of the present invention is illustrated in
FIG. 1, in which the shunt device 100 is shown in a side view. The
shunt device 100 is comprised of two portions, a proximal portion
30 which joins one or more distal portions 40. The proximal portion
30 is tubular, containing one or more lumens in either a concentric
or parallel internal configuration. In the exemplary embodiment of
the present invention, the proximal portion 30 is constructed of a
biologically inert, flexible material such as silicone or similar
polymers. Alternate materials might include, but are not limited
to, thin-walled Teflon, polypropylene, or other polymers or
plastics.
[0035] At its proximal end, the proximal portion 30 is attached to
a connector 25 which provides fluid communication between one or
more lumens within the proximal portion 30 and standard connectors
for medical syringe attachment. In the exemplary embodiment of the
present invention, the connector provides such communication with
separate subconnectors 10 and 20. Subconnector 10 terminally
connects to syringe attachment 5, which provides a connection for a
syringe [not shown] used to inject materials into one or more
communicating lumens within the proximal portion 30. Subconnector
20 terminally connects to syringe attachment 15, which provides a
connection for a syringe [not shown] used to inject materials into
one or more communicating lumens within the proximal portion 30.
Subconnector 20 may also allow passage therethrough for a guidewire
71 with a blunted tip 72.
[0036] The proximal portion 30 of the catheter connects with the
distal portion 40. The lumen(s) of the proximal portion 30 each
connect with a corresponding lumen within the distal portion 40.
The distal portion 40 is sized and shaped to be received within
Schlemm's canal in the eye. In an alternate embodiment, the distal
portion 40 may be a continuous, tapering extension of the proximal
portion 30. The distal portion 40 terminates in a tip 70 which may
be tapered and/or blunted, and may be open or closed. In the
embodiment shown in FIG. 1, the distal tip of the guidewire 72
extends slightly beyond the tip 70 of the distal portion 40 of the
device. In the embodiment shown in FIG. 1, the distal portion has a
concentric inflatable sleeve 50. In an alternate embodiment, distal
to the inflatable sleeve 50, the distal portion 40 may continue as
a fenestrated catheter 60, containing one or more fenestrations
65.
[0037] FIG. 2 shows a cross section at point A-A' through the
embodiment of the present invention as indicated in FIG. 1. In this
embodiment, a concentric, dual lumen catheter is provided, with an
outer tube 44 and an inner tube 48. An outer tube lumen 45 is
defined between the walls of the outer tube 44 and the inner tube
48. An inner tube lumen 49 is present within the inner tube 48.
[0038] A longitudinal cross-section detailing the terminal aspect
of the distal portion 40 in this embodiment of the present
invention is shown in FIG. 3. In this embodiment, the outer tube 44
is continuous with the inflatable sleeve 50, and the outer tube 44
terminates in a sealed end 55 at the distal end of the inflatable
sleeve 50. The inner tube 48 extends through the center of the
inflatable sleeve 50, and continues distal to the inflatable sleeve
50 as the fenestrated catheter 60. In the present embodiment, the
fenestrated catheter 60 contains a plurality of fenestrations. 65,
and terminates in a blunted, sealed distal catheter tip 70.
[0039] In an alternate embodiment of the present invention, as
shown in FIG. 4, the inflatable sleeve 50 is continuous as a
terminal extension of the inner tube 48, and the device terminates
in a blunted distal catheter tip 70 just distal to the inflatable
sleeve 50. In this embodiment of the present invention, the outer
tube 44 is continuous with the fenestrated catheter 60 terminally,
such that the fenestrations 65 communicate with the outer lumen 45.
In this embodiment, the inflatable sleeve 50 is controlled through
the inner lumen 49, which is in continuous communication with the
lumen of the inflatable sleeve 50. Any materials intended to be
injected into Schlemm's canal are introduced through the outer
lumen 45, and pass through the fenestrations 65 into Schlemm's
canal proximal to the inflatable sleeve 50.
[0040] The surgical anatomy relevant to the present invention is
illustrated in FIG. 5. Generally, FIG. 5 shows Schlemm's canal 110
and the pupil 120, with the anatomic relationship of those
structures to the anterior chamber 135, the iris 140, cornea 145,
trabecular meshwork 150, and lens 170.
[0041] The surgical placement and functionality of the present
invention is shown from a frontal perspective in FIGS. 6-8. FIG. 6
shows the use of an embodiment like that shown in FIG. 3, in which
the inflatable sleeve 50 is proximal to the fenestrated catheter
60. The distal portion 40 of the device is threaded into Schlemm's
canal 110 through a surgical incision 105, such that the inflatable
sleeve 50 is entirely received into the canal 110.
[0042] The guidewire 71 may be used during surgical placement of
the device to afford temporary rigidity to the device to facilitate
its placement. Once placement is achieved, the guidewire 71 may be
withdrawn, leaving the device 100 in the desired anatomic
position.
[0043] Once the distal portion 40 of the catheter is satisfactorily
placed within Schlemm's canal 110, the inflatable sleeve 50 is
inflated by an injection of liquid material or air through the
outer lumen 45 of the catheter. The inflation of the inflatable
sleeve 50 serves to seal Schlemm's canal 110. Subsequent injection
of a desired material through the inner lumen 49 of the catheter is
expressed through the fenestrated catheter 60, causing local
expansion of Schlemm's canal 110 distal to the inflatable sleeve
50.
[0044] FIG. 8 shows the functionality of an embodiment like that
shown previously in FIG. 4, in which the inflatable sleeve 50 is
located terminally, and the fenestrations 65 are in the wall of the
outer tube 44 towards the catheter tip. When the inflatable sleeve
50 is inflated by injection into the inner tube 48, Schlemm's canal
110 is effectively sealed distal to the inflated sleeve 50.
Subsequent injection of a desired material through the outer lumen
45 of the catheter is expressed through the fenestrated catheter
60, causing local expansion of Schlemm's canal 110 proximal to the
inflatable sleeve 50.
[0045] The surgical procedure necessary to insert the device
requires an approach through a fornix-based conjunctival flap. A
partial thickness scleral flap is then created and dissected
half-thickness into clear cornea. A radial incision is made at the
limbus beneath the scleral flap and deepened until Schlemm's canal
is entered posteriorly. The anterior chamber may be deepened with
injection of a viscoelastic and a miotic agent. The distal portion
of the catheter device is grasped and threaded into Schlemm's
canal. At the desired position, the catheter device is inflated to
expand Schlemm's canal. The device is then deflated and withdrawn.
The scleral flap and conjunctival wound are closed in a
conventional manner.
[0046] While the above-described embodiments are exemplary, the
invention contemplates a wide variety of shapes and configurations
of the catheter to provide fluid communication between the anterior
chamber and Schlemm's canal. The above-described embodiments are
therefore not intended to be limiting to the scope of the claims
and equivalents thereof.
* * * * *