U.S. patent application number 13/220558 was filed with the patent office on 2012-03-29 for ocular implant with anchoring mechanism and multiple outlets.
This patent application is currently assigned to GLAUKOS CORPORATION. Invention is credited to Thomas W. Burns, David S. Haffner, Gregory T. Smedley, Hosheng Tu.
Application Number | 20120078158 13/220558 |
Document ID | / |
Family ID | 40342861 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120078158 |
Kind Code |
A1 |
Haffner; David S. ; et
al. |
March 29, 2012 |
OCULAR IMPLANT WITH ANCHORING MECHANISM AND MULTIPLE OUTLETS
Abstract
Devices and methods for treating ocular disorders are disclosed.
One ocular implant, has a substantially straight, rigid, elongate
body. The body has a self-trephinating distal portion that narrows
toward a distal end, and at least one inlet that communicates with
at least one inner lumen that communicates with a plurality of
outlets. The lumen has a sufficient length to extend from an
anterior chamber of an eye to a physiologic outflow pathway. An
anchor member extends from the implant.
Inventors: |
Haffner; David S.; (Mission
Viejo, CA) ; Smedley; Gregory T.; (Aliso Viejo,
CA) ; Burns; Thomas W.; (Dana Point, CA) ; Tu;
Hosheng; (Newport, CA) |
Assignee: |
GLAUKOS CORPORATION
Laguna Hills
CA
|
Family ID: |
40342861 |
Appl. No.: |
13/220558 |
Filed: |
August 29, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12338743 |
Dec 18, 2008 |
8007459 |
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13220558 |
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10667580 |
Sep 22, 2003 |
7488303 |
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12338743 |
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60412637 |
Sep 21, 2002 |
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Current U.S.
Class: |
604/8 |
Current CPC
Class: |
A61F 9/00781
20130101 |
Class at
Publication: |
604/8 |
International
Class: |
A61F 9/00 20060101
A61F009/00 |
Claims
1. (canceled)
2. A system for treating an ocular disorder, comprising: an implant
configured to be implanted into eye tissue such that when in use
the implant conducts fluid from an anterior chamber of an eye to a
physiologic outflow pathway of the eye, the implant comprising an
anchor member being located at a distal portion of an outflow end
of the implant; and a pressure sensor coupled to the implant.
3. The system of claim 2, wherein the eye tissue comprises a
trabecular meshwork.
4. The system of claim 2, wherein the physiologic outflow pathway
comprises Schlemm's canal.
5. The system of claim 2, wherein the physiologic outflow pathway
comprises an aqueous vein.
6. The system of claim 2, wherein the anchor member comprises a
scleral anchor having a trephining head that is configured to be
embedded within scleral tissue upon implantation.
7. The system of claim 2, wherein the implant comprises a
biocompatible material in or on the implant, and wherein the
biocompatible material is selected from the group consisting of
polyvinyl alcohol, polyvinyl pyrolidone, collagen, heparinized
collagen, tetrafluoroethylene, fluorinated polymer, fluorinated
elastomer, flexible fused silica, polyolefin, polyester, titanium,
stainless steel, Nitinol, and polysilicon.
8. The system of claim 2, wherein the implant has a surface coating
configured to elute therapeutic drugs into aqueous humor in the
anterior chamber.
9. A system for treating an ocular disorder, comprising: an implant
configured to be implanted into eye tissue such that when in use
the implant conducts fluid from an anterior chamber of an eye to an
existing physiologic outflow pathway of the eye, the implant
comprising a sensor; and a delivery device configured to advance
the implant and the sensor from within the anterior chamber to an
implantation site, the delivery device being configured to access
the anterior chamber through an opening formed in the eye.
10. The system of claim 9, wherein the existing physiologic outflow
pathway comprises Schlemm's canal.
11. The system of claim 9, wherein the existing physiologic outflow
pathway comprises an aqueous vein.
12. The system of claim 9, wherein the implantation site comprises
a trabecular meshwork of the eye such that when the implant is
implanted an inlet end of the implant is positioned in the anterior
chamber, an outflow end of the implant is positioned beyond the
trabecular meshwork, and a middle section of the implant is
positioned about the trabecular meshwork.
13. The system of claim 12, wherein the outflow end comprises a
distal anchor with a trephining head, the trephining head being
configured to penetrate the trabecular meshwork.
14. The system of claim 13, wherein the trephining head is
configured to penetrate into scleral tissue to anchor the
implant.
15. The system of claim 9, wherein the implant comprises a
biocompatible material in or on the implant, and wherein the
biocompatible material is selected from the group consisting of
polyvinyl alcohol, polyvinyl pyrolidone, collagen, heparinized
collagen, tetrafluoroethylene, fluorinated polymer, fluorinated
elastomer, flexible fused silica, polyolefin, polyester, titanium,
stainless steel, Nitinol, and polysilicon.
16. The system of claim 9, wherein the implant has a surface
coating configured to elute therapeutic drugs into aqueous humor in
the anterior chamber.
17. The system of claim 9, wherein the sensor is coupled to the
implant.
18. A system for treating an ocular disorder, comprising: an
implant configured to be implanted into eye tissue such that when
in use the implant conducts fluid from an anterior chamber of an
eye to an existing physiologic outflow pathway of the eye, the
implant comprising an anchor member; and a pressure sensor coupled
to the implant.
19. The system of claim 18, wherein the eye tissue comprises a
trabecular meshwork.
20. The system of claim 18, wherein the existing physiologic
outflow pathway comprises Schlemm's canal.
21. The system of claim 18, wherein the existing physiologic
outflow pathway comprises an aqueous vein.
22. The system of claim 18, wherein the anchor member comprises a
scleral anchor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/338,743, filed Dec. 18, 2008, which is a
divisional of U.S. patent application Ser. No. 10/667,580, filed
Sep. 22, 2003, now U.S. Pat. No. 7,488,303, which claims the
priority benefit of U.S. Provisional Application No. 60/412,637,
filed Sep. 21, 2002, the entirety of each one of which is hereby
incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention generally relates to improved medical
devices and methods for the reduction of elevated pressure in
organs of the human body. More particularly, the present invention
relates to the treatment of glaucoma by implanting a glaucoma stent
in an eye to reduce the intraocular pressure, wherein the glaucoma
stent is to drain aqueous from the anterior chamber by bypassing
diseased trabecular meshwork at the level of trabecular meshwork
and use/restore existing outflow pathways.
BACKGROUND OF THE INVENTION
[0003] About two percent of people in the United States have
glaucoma. Glaucoma is a group of eye diseases that causes
pathological changes in the optic disk and corresponding visual
field loss resulting in blindness if untreated. Intraocular
pressure elevation is the major etiologic factor in all
glaucomas.
[0004] In glaucomas associated with an elevation in eye pressure
the source of resistance to outflow is in the trabecular meshwork.
The tissue of the trabecular meshwork allows the "aqueous" to enter
Schlemm's canal, which then empties into aqueous collector channels
in the posterior wall of Schlemm's canal and then into aqueous
veins. The aqueous or aqueous humor is a transparent liquid that
fills the region between the cornea at the front of the eye and the
lens. The aqueous humor is constantly secreted by the ciliary body
around the lens, so there is a continuous flow of the aqueous humor
from the ciliary body to the eye's front chamber. The eye's
pressure is determined by a balance between the production of
aqueous and its exit through the trabecular meshwork (major route)
or via uveal scleral outflow (minor route). The trabecular meshwork
is located between the outer rim of the iris and the internal
periphery of the cornea. The portion of the trabecular meshwork
adjacent to Schlemm's canal causes most of the resistance to
aqueous outflow (juxtacanilicular meshwork).
[0005] Glaucoma is grossly classified into two categories:
closed-angle glaucoma and open-angle glaucoma. The closed-angle
glaucoma is caused by closure of the anterior angle by contact
between the iris and the inner surface of the trabecular meshwork.
Closure of this anatomical angle prevents normal drainage of
aqueous humor from the anterior chamber of the eye. Open-angle
glaucoma is any glaucoma in which the angle of the anterior chamber
remains open, but the exit of aqueous through the trabecular
meshwork is diminished. The exact cause for diminished filtration
is unknown for most cases of open-angle glaucoma. However, there
are secondary open-angle glaucomas that may include edema or
swelling of the trabecular spaces (from steroid use), abnormal
pigment dispersion, or diseases such as hyperthyroidism that
produce vascular congestion.
[0006] All current therapies for glaucoma are directed at
decreasing intraocular pressure. This is initially by medical
therapy with drops or pills that reduce the production of aqueous
humor or increase the outflow of aqueous. However, these various
drug therapies for glaucoma are sometimes associated with
significant side effects, such as headache, blurred vision,
allergic reactions, death from cardiopulmonary complications and
potential interactions with other drugs. When the drug therapy
fails, surgical therapy is used. Surgical therapy for open-angle
glaucoma consists of laser (trabeculoplasty), trabeculectomy and
aqueous shunting implants after failure of trabeculectomy or if
trabeculectomy is unlikely to succeed. Trabeculectomy is a major
surgery that is most widely used and is augmented with topically
applied anticancer drugs such as 5-flurouracil or mitomycin-c to
decrease scarring and increase surgical success.
[0007] Approximately 100,000 trabeculectomies are performed on
Medicare age patients per year in the United States. This number
would increase if the morbidity associated with trabeculectomy
could be decreased. The current morbidity associated with
trabeculectomy consists of failure (10-15%), infection (a life long
risk about 2-5%), choroidal hemorrhage (1%, a severe internal
hemorrhage from pressure too low resulting in visual loss),
cataract formation, and hypotony maculopathy (potentially
reversible visual loss from pressure too low).
[0008] If it were possible to bypass the local resistance to
outflow of aqueous at the point of the resistance and use existing
outflow mechanisms, surgical morbidity would greatly decrease. The
reason for this is that the episcleral aqueous veins have a
backpressure that would prevent the eye pressure from going too
low. This would virtually eliminate the risk of hypotony
maculopathy and choroidal hemorrhage. Furthermore, visual recovery
would be very rapid and risk of infection would be very small (a
reduction from 2-5% to 0.05%). Because of these reasons surgeons
have tried for decades to develop a workable surgery for the
trabecular meshwork.
[0009] The previous techniques, which have been tried, are
goniotomy/trabeculotomy, and other mechanical disruption of the
trabecular meshwork, such as trabeculopuncture, goniophotoablation,
laser trabecular ablation and goniocurretage. They are briefly
described below.
[0010] Goniotomy/Trabeculotomy: Goniotomy and trabeculotomy are
simple and directed techniques of microsurgical dissection with
mechanical disruption of the trabecular meshwork. These initially
had early favorable responses in the treatment of open-angle
glaucoma. However, long-term review of surgical results showed only
limited success in adults. In retrospect, these procedures probably
failed secondary to repair mechanisms and a process of "filling
in". The filling in is the result of a healing process that has the
detrimental effect of collapsing and closing in of the created
opening throughout the trabecular meshwork. Once the created
openings close, the pressure builds back up and the surgery
fails.
[0011] Trabeculopuncture: Q-switched Neodymium (Nd):YAG lasers also
have been investigated as an optically invasive technique for
creating full-thickness holes in trabecular meshwork. However, the
relatively small hole created by this trabeculopuncture technique
exhibits a filling in effect and fails.
[0012] Goniophotoablation/Laser Trabecular Ablation:
Goniophotoablation is disclosed by Berlin in U.S. Pat. No.
4,846,172, and describes the use of an excimer laser to treat
glaucoma by ablating the trabecular meshwork. This was not
demonstrated by clinical trial to succeed. Hill et al. used an
Erbium:YAG laser to create full thickness holes through trabecular
meshwork (Hill et al., Lasers in Surgery and Medicine 11:341-346,
1991). This technique was investigated in a primate model and a
limited human clinical trial at the University of California,
Irvine. Although morbidity was zero in both trials, success rates
did not warrant further human trials. Failure again was from
filling in of created defects in trabecular meshwork by repair
mechanisms. Neither of these is a valid surgical technique for the
treatment of glaucoma.
[0013] Goniocurretage: This is an ab-interno (from the inside)
mechanical disruptive technique. This uses an instrument similar to
a cyclodialysis spatula with a microcurrette at the tip. Initial
results are similar to trabeculotomy that fails secondary to repair
mechanisms and a process of filling in.
[0014] Although trabeculectomy is the most commonly performed
filtering surgery, Viscocanulostomy (VC) and non-penetrating
trabeculectomy (NPT) are two new variations of filtering surgery.
These are ab-externo (from the outside), major ocular procedures in
which Schlemm's canal is surgically exposed by making a large and
very deep scleral flap. In the VC procedure, Schlemm's canal is
cannulated and viscoelastic substance injected (which dilates
Schlemm's canal and the aqueous collector channels). In the NPT
procedure, the inner wall of Schlemm's canal is stripped off after
surgically exposing the canal.
[0015] Trabeculectomy, VC, and NPT are performed under a
conjunctival and scleral flap, such that the aqueous humor is
drained onto the surface of the eye or into the tissues located
within the lateral wall of the eye. Normal physiological outflows
are not used. These surgical operations are major procedures with
significant ocular morbidity. When Trabeculectomy, VC, and NPT are
thought to have a low chance for success, a number of implantable
drainage devices have been used to ensure that the desired
filtration and outflow of aqueous humor through the surgical
opening will continue. The risk of placing a glaucoma drainage
implant also includes hemorrhage, infection and postoperative
double vision that is a complication unique to drainage
implants.
[0016] All of the above embodiments and variations thereof have
numerous disadvantages and moderate success rates. They involve
substantial trauma to the eye and require great surgical skill by
creating a hole over the full thickness of the sclera/cornea into
the subconjunctival space. Furthermore, normal physiological
outflow pathways are not used. The procedures are mostly performed
in an operating room generating a facility fee, anesthesiologist's
professional fee and have a prolonged recovery time for vision. The
complications of filtration surgery have inspired ophthalmic
surgeons to look at other approaches to lowering intraocular
pressure.
[0017] The trabecular meshwork and juxtacanilicular tissue together
provide the majority of resistance to the outflow of aqueous and,
as such, are logical targets for surgical removal in the treatment
of open-angle glaucoma. In addition, minimal amounts of tissue are
altered and existing physiologic outflow pathways are utilized.
Trabecular bypass surgery has the potential for much lower risks of
choroidal hemorrhage, infection and uses existing physiologic
outflow mechanisms. This surgery could be performed under topical
anesthesia in a physician's office with rapid visual recovery.
[0018] Therefore, there is a great clinical need for the treatment
of glaucoma by a method that would be faster, safer and less
expensive than currently available modalities. Trabecular bypass
surgery is an innovative surgery that uses a micro stent, shunt, or
other implant to bypass diseased trabecular meshwork alone at the
level of trabecular meshwork and use or restore existing outflow
pathways. The object of the present invention is to provide a means
and methods for treating elevated intraocular pressure in a manner
which is simple, effective, disease site specific and can be
performed on an outpatient basis.
SUMMARY OF THE INVENTION
[0019] Some aspects of the invention comprise an implant for
treating glaucoma, the implant comprising: a first portion
configured to be embedded in the sclera of an eye, to anchor the
implant; a second portion configured to be positioned in the
anterior chamber of the eye and to receive fluid from the anterior
chamber; an intermediate portion between the first portion and the
second portion, the intermediate portion configured to span the
trabecular meshwork of the eye, so as to permit drainage of fluid
between the anterior chamber and Schlemm's canal; and a plurality
of longitudinally spaced openings in the intermediate portion.
[0020] Some aspects of the invention comprise an implant for
treating glaucoma in an eye, the implant having a longitudinal
implant axis, and comprising: an outflow portion through which the
longitudinal implant axis passes, the outflow portion shaped and
sized to be: (a) introduced through Schlemm's canal of the eye with
the portion of the longitudinal implant axis at an angle to
Schlemm's canal; and (b) received at least partially within
Schlemm's canal regardless of a rotational orientation of the
outflow portion about the longitudinal implant axis during the
introduction; a plurality of openings in the outflow portion, the
openings allowing fluid to communicate from a lumen within the
outflow portion to a location outside the outflow portion; an
inflow portion configured to permit communication of fluid from the
anterior chamber of the eye to the outflow portion; and an
anchoring member at one end of the implant.
[0021] Some aspects of the invention comprise an implant for
treating glaucoma, comprising: an outflow portion, sized and shaped
to be received at least partially within Schlemm's canal; an inflow
portion in fluid communication with the outflow portion, the inflow
portion configured to be disposed in the anterior chamber of the
eye; and a central portion extending between the inflow and outflow
portions; the outflow portion having a diameter that is no more
than three times the diameter of the central portion; a plurality
of openings in the outflow portion, the openings allowing fluid to
communicate from a lumen within the outflow portion to a location
outside the outflow portion; and an anchoring member at one end of
the implant, the anchoring member configured to anchor the implant
in the sclera of the eye.
[0022] In some embodiments, the implant further comprises at least
one opening in the central portion.
[0023] Some aspects of the invention comprise a kit for delivering
implants for treating an ophthalmic condition, the kit comprising:
an elongate body, the elongate body sized to be introduced into an
eye through an incision in the eye; an implant positionable on or
in the elongate body, the implant comprising: an outflow portion,
sized and shaped to be received at least partially within Schlemm's
canal; an inflow portion in fluid communication with the outflow
portion, the inflow portion configured to be disposed in the
anterior chamber of the eye; a plurality of openings in the outflow
portion, the openings allowing fluid to communicate from a lumen
within the outflow portion to a location outside the outflow
portion; and an anchoring member at one end of the implant, the
anchoring member configured to anchor the implant in the sclera of
the eye.
[0024] In some embodiments, the elongate body in the kit comprises
a tube, and the implant is positionable at least partially in the
tube.
[0025] Some embodiments comprise method of treating glaucoma, the
method comprising: inserting an elongate body into the trabecular
meshwork and Schlemm's canal of an eye, the elongate body
comprising a plurality of fluid channels and a plurality of
openings, each of the openings permitting fluid to flow from at
least one of the channels through the opening to a location outside
the elongate body; and introducing fluid through at least two of
the fluid channels into the eye.
[0026] Some embodiments further comprise positioning the implant
such that a first opening of said plurality of openings is at
Schlemm's canal of the eye. Some embodiments further comprise
positioning the implant such that a second opening of said
plurality of openings is at the trabecular meshwork and/or the
sclera of the eye.
[0027] In some embodiments, the inserting comprises inserting the
elongate body from the anterior chamber through the trabecular
meshwork of the eye and into Schlemm's canal of the eye.
[0028] Some embodiments include implanting a trabecular stent in an
eye to reduce intraocular pressure, wherein the trabecular stent
drains aqueous from the anterior chamber by bypassing diseased
trabecular meshwork at the level of trabecular meshwork and use
existing outflow pathways.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Additional objects and features of the present invention
will become more apparent and the invention itself will be best
understood from the following Detailed Description of Exemplary
Embodiments, when read with reference to the accompanying
drawings.
[0030] FIG. 1 is a sectional view of an eye.
[0031] FIG. 2 is a close-up sectional view, showing the anatomy of
the trabecular meshwork and the anterior chamber of the eye.
[0032] FIG. 3 is an axisymmetric glaucoma stent that is intended to
be placed noncircumferentially in Schlemm's canal.
[0033] FIG. 4 is a stent delivery system comprising irrigation and
aspiration capabilities.
[0034] FIG. 5 is a cross-sectional view of the stent delivery
system of FIG. 4.
[0035] FIG. 6 is a multi-lumen tubing shaft as a component of the
stent delivery system.
[0036] FIG. 7 is a perspective view of the stent with a stent
delivery system.
[0037] FIG. 8 is one embodiment of an ab interno stent delivery
applicator.
[0038] FIG. 9 shows a distal section of the ab interno stent
delivery applicator of FIG. 8.
[0039] FIG. 10 shows a procedure for implanting a stent in an ab
interno process.
[0040] FIG. 11 shows one embodiment of an ab externo stent delivery
applicator.
[0041] FIG. 12 shows a distal section of the ab externo stent
delivery applicator of FIG. 11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] In accordance with a preferred method, trabecular bypass
surgery creates an opening or a hole through the diseased
trabecular meshwork through minor microsurgery. To prevent "filling
in" of the hole, a biocompatible elongate implant is placed within
the hole as a trabecular stent, which may include, for example, a
solid rod or hollow tube. In one exemplary embodiment, the
trabecular stent implant may be positioned across the diseased
trabecular meshwork alone and it does not extend into the eye wall
or sclera. In another embodiment, the inlet end of the implant is
exposed to the anterior chamber of the eye while the outlet end is
positioned at the exterior surface of the trabecular meshwork. In
another exemplary embodiment, the outlet end is positioned at and
over the exterior surface of the trabecular meshwork and into the
fluid collection channels of the existing outflow pathways. In
still another embodiment, the outlet end is positioned in the
Schlemm's canal. In an alternative embodiment, the outlet end
enters into fluid collection channels up to the level of the
aqueous veins with the trabecular stent inserted in a retrograde or
antegrade fashion.
[0043] According to some embodiments, the trabecular stent implant
is made of biocompatible material, which is either hollow to allow
the flow of aqueous humor or solid biocompatible material that
imbibes aqueous. The material for the trabecular stent may be
selected from the group consisting of porous material, semi-rigid
material, soft material, hydrophilic material, hydrophobic
material, hydrogel, elastic material, and the like.
[0044] In further accordance with some embodiments, the trabecular
stent implant may be rigid or it may be made of relatively soft
material and is somewhat curved at its distal section to fit into
the existing physiological outflow pathways, such as Schlemm's
canal. The distal section inside the outflow pathways may have an
oval shape to stabilize the trabecular stent in place without undue
suturing. Stabilization or retention of the trabecular stent may be
further strengthened by a taper end and/or by at least one ridge or
rib on the exterior surface of the distal section of the trabecular
stent, or other surface alterations designed to retain the
trabecular stent.
[0045] In one embodiment, the trabecular stent may include a
micropump, pressure sensor, one-way valve, or semi-permeable
membrane to minimize reflux of red blood cells or serum protein. It
may also be useful to use a biocompatible material that hydrates
and expands after implantation so that the trabecular stent is
locked into position around the trabecular meshwork opening or
around the distal section of the trabecular stent.
[0046] One of the advantages of trabecular bypass surgery, as
disclosed herein, and the use of a trabecular stent implant to
bypass diseased trabecular meshwork at the level of trabecular
meshwork and thereby use existing outflow pathways is that the
treatment of glaucoma is substantially simpler than in existing
therapies. A further advantage of the invention is the utilization
of simple microsurgery that may be performed on an outpatient basis
with rapid visual recovery and greatly decreased morbidity.
Finally, a distinctly different approach is used than is found in
existing implants. Physiological outflow mechanisms are used or
re-established by the implant of the present invention, in
contradistinction with previously disclosed methodologies. The
procedure for implanting a trabecular stent of the present
invention may be accomplished by ab interno and/or ab externo
procedures.
[0047] FIGS. 1 to 7 show an embodiment of a glaucoma stent and its
delivery system for the treatment of glaucoma by implanting a
trabecular or glaucoma stent. In particular, a trabecular stent
implant is used to bypass diseased trabecular meshwork at the level
of trabecular meshwork to use or restore existing outflow pathways
and methods thereof.
[0048] For background illustration, FIG. 1 shows a sectional view
of an eye 10, while FIG. 2 shows a close-up view, showing the
relative anatomical locations of the trabecular meshwork, the
anterior chamber, and Schlemm's canal. Thick collagenous tissue
known as sclera 11 covers the entire eye 10 except that portion
covered by the cornea 12. The cornea 12 is a thin transparent
tissue that focuses and transmits light into the eye and the pupil
14, which is the circular hole in the center of the iris 13
(colored portion of the eye). The cornea 12 merges into the sclera
11 at a juncture referred to as the limbus 15. The ciliary body 16
begins internally in the eye and extends along the interior of the
sclera 11 and becomes the choroid 17. The choroid 17 is a vascular
layer of the eye underlying retina 18. The optic nerve 19 transmits
visual information to the brain and is sequentially destroyed by
glaucoma.
[0049] The anterior chamber 20 of the eye 10, which is bound
anteriorly by the cornea 12 and posteriorly by the iris 13 and lens
26, is filled with aqueous. Aqueous is produced primarily by the
ciliary body 16 and reaches the anterior chamber angle 25 formed
between the iris 13 and the cornea 12 through the pupil 14. In a
normal eye, the aqueous is removed through the trabecular meshwork
21. Aqueous passes through trabecular meshwork 21 into Schlemm's
canal 22 and through the aqueous veins 23, which merge with
blood-carrying veins, and into venous circulation. Intraocular
pressure of the eye 10 is maintained by the intricate balance of
secretion and outflow of the aqueous in the manner described above.
Glaucoma is characterized by the excessive buildup of aqueous fluid
in the anterior chamber 20, which produces an increase in
intraocular pressure (fluids are relatively incompressible and
pressure is directed equally to all areas of the eye).
[0050] As shown in FIG. 2, the trabecular meshwork 21 constitutes a
small portion of the sclera 11. It is understandable that creating
a hole or opening for implanting a device through the tissues of
the conjunctiva 24 and sclera 11 is relatively a major surgery as
compared to a surgery for implanting a device through the
trabecular meshwork 21 only.
[0051] Some embodiments include a method for increasing aqueous
humor outflow in an eye of a patient to reduce the intraocular
pressure therein. The method comprises bypassing diseased
trabecular meshwork at a level of the trabecular meshwork with a
trabecular stent implant and using existing outflow pathways. The
trabecular stent implant may be an elongate trabecular stent or
other appropriate shape, size, or configuration. In one embodiment
of an elongate trabecular stent implant, the trabecular stent has
an inlet end, an outlet end and a lumen therebetween, wherein the
inlet end is positioned at an anterior chamber of the eye and the
outlet end is positioned at about an exterior surface of the
diseased trabecular meshwork. Furthermore, the outlet end may be
positioned into fluid collection channels of the existing outflow
pathways. Optionally, the existing outflow pathways may comprise
Schlemm's canal 22. The outlet end may be further positioned into
fluid collection channels up to the level of the aqueous veins with
the trabecular stent inserted either in a retrograde or antegrade
fashion with respect to the existing outflow pathways.
[0052] In a further alternate embodiment, a method is disclosed for
increasing aqueous humor outflow in an eye of a patient to reduce
an intraocular pressure therein. The method comprises (a) creating
an opening in trabecular meshwork, wherein the trabecular meshwork
comprises an interior side and exterior side; (b) inserting a
trabecular stent implant into the opening; and (c) transporting the
aqueous humor by the trabecular stent implant to bypass the
trabecular meshwork at the level of the trabecular meshwork from
the interior side to the exterior side of the trabecular
meshwork.
[0053] The trabecular stent implant may comprise a biocompatible
material, such as a medical grade silicone, for example, the
material sold under the trademark Silastic.TM. which is available
from Dow Corning Corporation of Midland, Mich., or polyurethane,
which is sold under the trademark Pellethane.TM., which is also
available from Dow Corning Corporation. In an alternate embodiment,
other biocompatible materials (biomaterials) may be used, such as
polyvinyl alcohol, polyvinyl pyrolidone, collagen, heparinized
collagen, tetrafluoroethylene, fluorinated polymer, fluorinated
elastomer, flexible fused silica, polyolefin, polyester, titanium,
stainless steel, Nitinol, shape-memory material, polysilicon,
mixture of biocompatible materials, and the like. In a further
alternate embodiment, a composite biocompatible material by surface
coating the above-mentioned biomaterial may be used, wherein the
coating material may be selected from the group consisting of
polytetrafluoroethylene (PTFE), polyimide, hydrogel, heparin,
therapeutic drugs, and the like.
[0054] FIG. 3 shows an axisymmetric glaucoma stent that is intended
to be placed non-circumferentially in Schlemm's canal 22 (i.e.,
with its long axis at an angle relative to the circumference of
Schlemm's canal 22), and that transports aqueous 57 from the
anterior chamber 20 to Schlemm's canal. The stent may comprise a
trephining head 52 at the distal end of the stent 51, wherein the
trephining head 52 is sized and configured to penetrate the
trabecular meshwork 21, Schlemm's canal 22 into sclera 11 for
anchoring. The outlet portion 53 may comprise a plurality of outlet
openings 56 spaced apart axially and configured for releasing
aqueous into Schlemm's canal 22 with ease. The middle section 54 of
the stent is generally placed at about the trabecular meshwork 21,
wherein the middle section may optionally comprise a plurality of
openings 58 spaced apart for effectively releasing aqueous 57 into
trabecular meshwork. The proximal end 55 of the stent 51 is
generally disposed in the anterior chamber 20 at a location not to
affect the aqueous flow or eye tissue movement. An axisymmetric
stent of the present invention is to overcome the flow resistance
in Schlemm's canal when a conventional stent is placed
circumferentially along the Schlemm's canal passageway that tends
to direct the aqueous flow in a defined direction.
[0055] FIG. 4 shows a stent delivery system 62 comprising
irrigation 64 and aspiration 67 capabilities. A trabecular or
glaucoma stent 61, particularly an axisymmetric stent, is placed
and grasped by a grasping tip 79 at the distal section of a
delivery system 62. In one aspect, the grasping tip 79 in a stent
delivery system with irrigation/aspiration is accomplished with a
concentric tubing 68 having swaged end details. The irrigation step
64 is carried out by injecting fluid out of the irrigation ports 65
to the anterior chamber 20. The aspiration step 67 is carried out
by returning fluid entering the aspiration ports 66. A plunger or
releasing element 63 is located concentrically within the lumen 70
of the delivery system 62. In one embodiment, after the stent is
placed in the target location, the tubing 68 is withdrawn back
toward the handpiece (at right-hand side in FIG. 4; not shown) to
release the stent 61.
[0056] FIG. 5 shows cross-sectional view of the stent delivery
system 62 of FIG. 4. The tubing 68 of the stent delivery system may
be formed on mandrel to create a first side channel 65A for
irrigation and a second side channel 66A for aspiration. The tight
fit 69 between an inner tubing 71 and the outer tubing 68 creates
barrier between the channel 65A for irrigation and the channel 66A
for aspiration.
[0057] FIG. 6 shows a multi-lumen tubing shaft 35 as a component of
the stent delivery system 62. This is an alternate configuration
for fluid irrigation and aspiration. The tubing shaft 35 comprises
a central lumen 31 that may carry a grasping tip 79 for stent
folding. The auxiliary lumens 32, 33 spaced apart or spaced at an
opposite side of the central lumen 31 are provided for fluid
irrigation/aspiration.
[0058] FIG. 7 shows a perspective view of the stent with a stent
delivery system. In an alternate embodiment, the delivery system 62
may comprise a stainless cone pin 37. The pin 37 is fixed
relatively to the stent 36, preferably an axisymmetric stent, when
the stent is placed at a target location, say inside Schlemm's
canal or at least a portion of the stent exposing to Schlemm's
canal or to a collecting channel. Instead of pushing the pin 37
forward to release the stent 36, it is configured to pull back the
multi-lumen tubing 35 so as to release the stent out of the
grasping tip 79.
[0059] In another aspect, the delivery system may comprise a
retainer ring on the tubing 35, wherein the retainer ring is
attached to a triggering mechanism in the handle and is used to
pull back the outer sleeve (or the tubing 35) with an economical
construction or manufacturing method.
[0060] Other aspects of the present invention may comprise sending
irrigation fluid, including viscoelastic, down the center a stent
delivery system. It is further disclosed that light means may be
sent down a clear pathway or through a clear extrusion for better
visualization, using the extrusion itself for light transmission.
It is another object of the present disclosure to provide fiber
optic imaging to validate placement of a stent in the target
location, say Schlemm's canal. In another aspect, it is provided to
using collet style mechanism to grip or grasp a stent during a
delivery phase or to retrieve objects in the cavity of a body. It
is also a common practice to use footswitch to release a stent in
the body.
[0061] Some aspects of the invention relate to a trabecular stent
comprising a distal end, a proximal end, and a plurality of outlet
openings spaced apart axially, wherein the proximal end is placed
in an anterior chamber and the distal end is placed in a sclera
posterior to Schlemm's canal, at least one opening being exposed to
Schlemm's canal.
[0062] In still another aspect of the present disclosure, RF energy
or other suitable energy (thermal, cryo, or laser) is used to
release a stent from its grasping tip. In a previously disclosed
bifurcatable stent, the stent may be sized and configured to have
at least one retaining arm at the end section of the stent body
that is about perpendicular to the stent body, wherein a first
retaining arm is used to be placed inside Schlemm's canal.
[0063] FIG. 8 shows one embodiment of an ab interno stent delivery
applicator 2. The applicator 2 comprises a distal section 29 and a
handle section 34. A stent 51 is loaded at the distal section 29 of
the applicator. The applicator further comprises a plurality of
fluid ports 41, 42, 43 for administering various fluids to various
target tissue sites. For example, the first fluid port 41 is
connected through a fluid channel 47 to a fluid supplier source 44,
wherein the fluid port 41 is configured to be placed at about the
sclera 11 of an eye 10 during the stent delivery phase. At least
one component of the fluid exiting the first fluid port 41 is
selected from a group consisting of genes, growth factors, drugs,
or nutrients for treating the sclera. In another example, the
second fluid port 42 is connected through a fluid channel 48 to a
fluid supplier source 45, wherein the fluid port 42 is configured
to be placed at about Schlemm's canal 22 of an eye 10 during the
stent delivery phase. At least one component in the fluid exiting
the second fluid port 42 is selected from a group consisting of
vasodilating agent, anti-glaucoma drug, and other drug suitably for
treating Schlemm's canal. In still another example, the third fluid
port 43 is connected through a fluid channel 49 to a fluid supplier
source 46, wherein the fluid port 43 is configured to be placed at
about the trabecular meshwork 21 of an eye 10 during the stent
delivery phase. At least one component in the fluid exiting the
third fluid port 43 may comprise, but not limited to, vasodilating
agent, anti-glaucoma drug, balanced saline solution or viscoelastic
for treating trabecular meshwork. All fluid channels 47, 48, and 49
of the applicator are suitably placed within a lumen 7 of the stent
delivery applicator 2.
[0064] FIG. 9 shows a distal section 29 of the ab interno stent
delivery applicator 2 of FIG. 8. In one embodiment, a pressure
monitor 44A is installed at a suitable place adjacent to the fluid
supplier source 44, wherein the pressure monitor 44A is sized and
configured to monitor the sensing pressure at about the first fluid
port 41. During the course of the stent delivery phase, the sensing
pressure at the first fluid port 41 reflects the pressures of the
anterior chamber 20, the trabecular meshwork 21, Schlemm's canal
22, and the sclera 11 in sequence. In one embodiment, when the
sensing pressure measured suddenly increases due to flow resistance
from the sclera, it is indicative that the distal end of the stent
51 is well in place in the sclera. Appropriate fluid can be
administered to the sclera 11 through the first fluid port 41.
Similarly, a second appropriate fluid can be administered to
Schlemm's canal through the second fluid port 42. And a third
appropriate fluid can be administered to trabecular meshwork
through the third fluid port 43. At the end of the stent delivery
phase, the stent 51 can be unloaded from the applicator 2 by
operating a knob 38 on the handle 34. Also shown are fluid channels
47, 48, and 49 of the applicator within the lumen 7 of the stent
delivery applicator 2.
[0065] FIG. 10 shows a procedure for implanting a stent 51 in an ab
interno process. First, a small incision 6 is created at an
appropriate location of the cornea 12 allowing inserting an
applicator 2 into the anterior chamber. The distal section 29 of
the applicator 2 advances across the eye and approaches the
trabecular meshwork 21. By further advancing the distal end, the
distal section 29 of the applicator 2 passes trabecular meshwork,
Schlemm's canal and reaches the sclera 11 behind Schlemm's canal
for anchoring the distal end of the stent into the sclera. The
stent is unloaded from the applicator thereafter.
[0066] Some aspects of the invention relate to a stent delivery
apparatus comprising a plurality of fluid exiting ports configured
axially along a distal section of the apparatus, wherein each port
is connected to a fluid supply, at least one fluid exiting port is
exposed to a sclera to provide a fluid to the sclera. In one
embodiment, the fluid is selected from a group consisting of genes,
growth factors, drugs, nutrients, and combination thereof for
treating the sclera. In another embodiment, the stent delivery
apparatus further comprises a second fluid exiting port being in
fluid communication with Schlemm's canal, wherein the fluid is
selected from a group consisting of genes, growth factors, drugs,
anti-glaucoma drug, anti-inflammatory drugs, vasodilating drugs,
nutrients, and combination thereof for treating the sclera.
[0067] FIG. 11 shows one embodiment of an ab externo stent delivery
applicator 3. The applicator 3 comprises a distal section 27 with a
self-trephining type sharp cut end 75 and a handle section 34. A
stent 51 is loaded within the distal section 27 with a sharp end 52
facing the operator. The applicator further comprises a plurality
of fluid ports 72, 73, 74, 84 for administering various fluids to
various target tissue sites. The multiple fluid channels and ports
can be configured in the applicator according to ways that are well
known to those of skill in the art, especially as seen in
cardiovascular catheters. Each fluid supply source (76, 77, 78, 82)
provides an appropriate fluid through a fluid channel (87, 86, 85,
83) to the fluid port (72, 73, 74, 84), respectively. All fluid
channels 83, 85, 86, 87 are suitably placed within a lumen 9 of the
stent delivery applicator 3 for providing a fluid to each fluid
port. An appropriate fluid with at least one active component can
be selected from a gene, growth factor, drug, anti-glaucoma drug,
vasodilating agent, saline, viscoelastic, anti-inflammatory drug,
and/or the like.
[0068] FIG. 12 shows a distal section 27 of the ab externo stent
delivery applicator 3 of FIG. 11. A pressure monitor 76A is
installed at a suitable place adjacent to the fluid supplier source
76, wherein the pressure monitor 76A is sized and configured to
monitor the sensing pressure at about the first fluid port 72. In
operations, the applicator 3 is inserted through a small opening at
the sclera 11 and advanced toward Schlemm's canal using an external
visualization aid that is known to one skilled in the art. During
the course of the stent delivery phase ab externo, the sensing
pressure at the first fluid port 72 reflects the pressures of the
sclera 11, Schlemm's canal 22, the trabecular meshwork 21, and the
anterior chamber 20 in sequence. In one embodiment, when the
sensing pressure continuously increases until reach a plateau at
the anterior chamber, it is indicative that the stent is ready to
be unloaded from the applicator 3. Appropriate fluids can be
administered to any or all of the following: the sclera 11 through
the fluid port 84, Schlemm's canal through the fluid port 74, the
trabecular meshwork through the fluid port 73, or the anterior
chamber 20 through the fluid port 72. At the end of the stent
delivery phase, the stent 51 can be unloaded from the applicator 3
by operating a knob 38 on the handle 34.
[0069] From the foregoing description, it should be appreciated
that a novel approach for the surgical treatment of glaucoma has
been disclosed for reducing intraocular pressure. While the
invention has been described with reference to specific
embodiments, the description is illustrative of the invention and
is not to be construed as limiting the invention. Various
modifications and applications may occur to those who are skilled
in the art, without departing from the true spirit and scope of the
invention, as described by the appended claims and their
equivalents.
* * * * *