U.S. patent application number 10/083089 was filed with the patent office on 2002-06-27 for catheter for applying medication into the endolymphatic sacs of the cochlea.
Invention is credited to Heermann, Ralf, Lenarz, Thomas.
Application Number | 20020082554 10/083089 |
Document ID | / |
Family ID | 7888289 |
Filed Date | 2002-06-27 |
United States Patent
Application |
20020082554 |
Kind Code |
A1 |
Lenarz, Thomas ; et
al. |
June 27, 2002 |
Catheter for applying medication into the endolymphatic sacs of the
cochlea
Abstract
A catheter for administering medication into the endolymphatic
sacs of the cochlea of the inner ear in humans, through at least
one membrane of the inner ear. The catheter is designed with at
least one outflow aperture at one end for the medication being
administered and with an anchoring element. A medication dosage
system can be connected to the other end of the catheter. The
outflow aperture can be fed through the membrane of the inner ear
and the anchoring element is designed so that it can anchor itself
against this membrane.
Inventors: |
Lenarz, Thomas; (Hannover,
DE) ; Heermann, Ralf; (Hannover, DE) |
Correspondence
Address: |
Collard & Roe, P.C.
1077 Northern Boulevard
Roslyn
NY
11576
US
|
Family ID: |
7888289 |
Appl. No.: |
10/083089 |
Filed: |
February 26, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10083089 |
Feb 26, 2002 |
|
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09443534 |
Nov 19, 1999 |
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6377849 |
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Current U.S.
Class: |
604/104 ;
604/174 |
Current CPC
Class: |
A61M 2025/0091 20130101;
A61N 1/36038 20170801; A61M 25/04 20130101; A61L 29/02 20130101;
A61M 2210/0662 20130101; A61F 11/00 20130101 |
Class at
Publication: |
604/104 ;
604/174 |
International
Class: |
A61M 029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 19, 1998 |
DE |
19853299.7 |
Claims
What is claimed is:
1. A catheter for administering medication into the endolymphatic
sacs of the inner ear in humans through at least one membrane of
the inner ear, the membranes comprising the membrane of the round
window, the membrane of the endolymphatic sac and the basilar
membrane, and the inner ear further having a stapes footplate, and
a scala tympani with an osseous border, comprising: a catheter tube
having two ends; at least one outflow aperture at one end of the
catheter tube for administration of the medication through one of
the membranes of the inner ear; an anchoring element at said one
end for anchoring the catheter directly against the membrane; and a
medication dosage system connected to the other end of the
catheter.
2. A catheter according to claim 1, wherein the anchoring element
comprises a disc arranged across and encompassing said catheter
tube for anchoring said catheter tube, said disc covering the round
window of the inner ear and having at least one anchoring stay on
an edge, said stay anchoring against an osseous border of the round
window, and further comprising a cannula point at said outflow
aperture, said cannula point being feedable through said
membrane.
3. A catheter according to claim 1, wherein the anchoring element
comprises a disc arranged across and encompassing said catheter
tube for anchoring said catheter tube to the basilar membrane, said
disc having at least one anchoring stay at an edge, said stay
anchoring against the osseous border of the scala tympani, and
further comprising a cannula point at said outflow aperture, said
cannula point being feedable through the scala tympani.
4. A catheter according to claims 2, wherein said cannula point is
connected to an electro-conductive cable.
5. A catheter according to claim 2, wherein said disc has a
diameter of 0.7 mm to 1.2 mm.
6. A catheter according to claim 1, wherein said cannula point is
made of a metallic material.
7. A catheter according to claim 1, wherein said one end has a
bulbous extension with an end surface containing said outflow
aperture, said bulbous extension having an outer diameter and being
designed with at least two concentric anchoring stays encompassing
said outflow aperture, said stays being made of a flexible material
with memory, wherein said anchoring stays are fed through the
footplate of the stapes of the oval window and which anchor
themselves against the inner surface of the joint.
8. A catheter according to claim 7, wherein said bulbous extension
is fitted with a clip, said clip anchoring itself against the
stapes footplate.
9. A catheter according to claim 7, wherein said bulbous extension
and said anchoring stays are enveloped in a removable tube having
an inner diameter corresponding to the outer diameter of said
bulbous extension.
10. A catheter according to claim 1, wherein said anchoring element
comprises a conical body with a front outflow aperture whose
minimum diameter is greater than the diameter of the catheter tube,
said conical body having at least two hook-like anchoring elements
bent backwards at an outer mantle, wherein said hook-like anchoring
elements together with a front sub-section of the conical body are
fed through said membrane encompassing the endolymphatic sac, and
anchor themselves against an inner surface of said membrane of the
endolymphatic sac.
11. A catheter according to claim 10, wherein said catheter is made
of a carbon material.
12. A catheter according to claim 10, wherein said catheter is made
of titanium dioxide ceramic.
Description
BACKGROUND OF THE INVENTION
[0001] The invention concerns a catheter for administering
medication into the endolymphatic sacs of the inner ear in humans,
through at least one membrane of the inner ear. The catheter has at
least one outflow aperture at one end for the medication being
administered. There is an anchoring element for the catheter at
this end to anchor the catheter to the membrane. There is also a
medication dosage system connected to the other end of the
catheter.
THE PRIOR ART
[0002] This kind of catheter is used to administer medication into
the endolymphatic sacs of the inner ear. Administration of
medication to the inner ear is sometimes necessary to combat ear
diseases and for balance. In particular, it is used for treating
symptoms such as loss of hearing, vertigo or ringing in the ears
(tinnitus). Tinnitus is described as the awareness of sound, such
as ringing or whistling, within the inner ear without there
actually being any external sound source.
[0003] The reasons for the emergence of these noises, only audible
to the patient, are numerous, and the pathogenesis of such has not
been clearly explained to date. Due to the difficulty in accessing
the inner ear to treat the respective illnesses, the administration
of medication has been standard. It has not been possible to
effectively treat diseases of the inner ear, or treatment has only
been performed with difficulty, due to the side effects of
medication. Nowadays, treatment for hearing loss in the inner ear,
vertigo or tinnitus is performed by vasoactive infusions, steroids
or hyperbaric oxygen therapy. Anaesthetics and antidepressants are
also used along with physical, surgical and psychotherapeutic
measures.
[0004] Systemically administered medication not only affects the
area of the inner ear but also the whole body. Side effects thereby
occur even with minimal dosage, which makes specific therapy of the
disorder of the inner ear impossible. The result of this is that
the majority of patients today cannot be effectively treated.
Physical, psychotherapeutic and surgical measures can only help in
a very small percentage of cases.
[0005] Meaningful and effective therapy to the inner ear can only
be achieved with a localized dose of drugs or by electrically
induced stimuli. However, specific application of drugs has always
posed problems.
[0006] In one known procedure, medication is administered via a
tympanic tube in the middle ear with subsequent uncontrolled
diffusion into the inner ear via the round window membrane. With
this type of known procedure, the only medication that can be
applied is that which is also diffusible, which is not the case
with some types of medication. In addition, it is virtually
impossible to determine, predict and monitor the diffusion rate of
diffusible substances. Therefore, the amount of medication selected
must err on the high side, so that an adequate amount of the
applied substance per diffusion can reach the inner ear.
[0007] A generically known catheter, such as that produced by
Neuro-Biometrix USA (now called Intra Ear) distributed under its
trading name "Round Window .mu. Cath" and "Round Window E Cath",
has a somewhat spherical flexible end portion, which is clamped
into the niche of the membrane of the round window and anchors
itself there. This ending has several apertures, from which the
medication can be discharged and diffuses right through the
membrane of the round window. These outflow apertures are spaced at
a distance from the membrane of the round window. However this
known catheter can only apply diffusible medication, as these
substances must be able to diffuse right through the membrane of
the round window.
[0008] It would be desirable to have a controllable direct
administration of medication into the lymph filled compartments of
the cochlea, as only then is specific therapy of the symptoms of
the disease possible. Since the lymphatic fluid in the cochlea
directly bathes the sensory cells requiring therapy, as a blood
supply for the sensory cells is not however immediately available,
it is therefore not possible to administer medication via the
bloodstream directly to the location of the damaged cells.
Therefore, the ability to control the direct administration of
medication into the inner ear fluids is desired. Until now, only
the following substances and methods have been available: steroids
and osmotically effective substances, tinnitus suppressant
medications from the group of membrane-effective drugs and
transmitter substances, neurotrophine (i.e., substances that
facilitate regeneration or protection of damaged inner ear auditory
cells and attacked aural nerve tissues), antioxidants, gene
therapy, the application of electrically charged particles for the
treatment of tinnitus and ototoxic medication for eliminating
equilibrium sensitive cells.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of this invention to design a
catheter of the kind mentioned previously, so that it facilitates
direct application of medication into the inner ear, and which also
offers safe and secure anchoring in the inner ear.
[0010] It is another object of the invention to provide a catheter
that will not negatively affect the auditory performance of the
patient and which can be removed again without any problems, once
therapy is complete.
[0011] These and other objects are achieved by way of a catheter
according to the invention having at least one outflow aperture at
one end for the medication being administered and with an anchoring
element. A medication dosage system can be connected to the other
end of the catheter. The outflow aperture can be fed through the
membrane of the inner ear, and the anchoring element is designed so
that it can anchor itself against this membrane.
[0012] The invention envisages a catheter of the type mentioned
above, designed so that the outflow aperture can be fed through the
tympanic membrane and the anchoring element anchors itself directly
against the membrane.
[0013] A catheter of this kind can be created in a surprisingly
simple manner to facilitate the direct application of medication
into the inner ear and provide safe and durable anchoring within
the inner ear. The catheter is designed so that it can be affixed
to the round window membrane, to the base of the stapes at the oval
window, or to the membrane of the endolymphatic sac, and the
medication is then fed into the compartment behind the
membrane.
[0014] The catheter according to the invention can also be combined
with a medication dosage system, particularly one for micro-dosage
system.
[0015] Depending upon whether the catheter according to the
invention is to be anchored at the round window membrane, to the
base of the stapes at the oval window, to the membrane of the
endolymphatic sac or to the bone between the scala tympani and the
cochlea duct, a posterior tympanotomy (starting at the drilled
tympanic membrane) is well suited as the access route to these
membranes for access to the round and oval windows, and the
transmeatal access route (via the auditory canal) is also suitable
for positioning the catheter according to the invention. A combined
access route can offer additional advantages where appropriate. The
catheter for the endolymphatic sac can be anchored within the
parameters of a mastoidectomy (starting at the drilled tympanic
membrane) and then exposing the sac in the area of the sigmoid
sinus. A diagonal incision in the area of the upper and lateral
sections is made. The catheter (depending on the size of the
system) is fed into the opening and anchors itself.
[0016] The configuration of the elements facilitates adequate
sealing of the exposed cochlear duct. The connective tissue
membrane offers additional security. Due to the flexible nature of
the suspending catheter at the respective membrane, deterioration
of auditory performance is not expected. Removal of the catheter
can be performed without damage, and closure of the lumens can be
achieved with connective tissue or similar tissue. A measuring
instrument or other instruments make the selection of size,
positioning, and fixing of the catheter very simple. It is possible
to integrate a wide variety of sensors and electrodes into the
catheter. It is also possible to design the catheter extremity with
various coupling elements to facilitate the attachment of a
micro-dosage system.
[0017] Another advantage of the catheter according to the present
invention is that it can be easily removed upon completion of
therapy. Upon removal of the catheter, the aperture left behind in
the corresponding membrane can be covered and closed up initially
with grafted tissue, so that fluid cannot flow through the opening
out of the inner ear. Subsequently, the scar tissue heals as a
natural process, whereupon the aperture completely closes up. This
scar tissue does not affect auditory performance.
[0018] In a preferred embodiment of the invention, one end is
designed with a disc arranged across and encompassing the catheter
tube for anchoring it to the round window membrane (or for
anchoring it to the basilar membrane) and having a cannula point
with an outflow aperture, which can be fed through the membrane.
The disc has at least one anchoring element on its edge, which is
designed to anchor against the osseous border of the round window
(or the basilar membrane). The cannula point can be combined with
an electro-conductive cable and may be made of a metallic material.
The disc can have a diameter of between 0.7 mm and 1.2 mm.
[0019] This catheter can take advantage of the anatomical geometry
of the round window and its membrane in a surprisingly simple way.
Then with the cannula point, disc and anchoring stays, it is only
necessary to pierce through the membrane of the round window with
the cannula point, after which the anchoring stay or stays snap
into the osseous border of the round window. This is because this
osseous border of the round window already has overhanging edges
that are well suited for positioning the anchoring elements.
[0020] In another embodiment of the invention, one end of the
catheter has a bulbous extension, the end wall of which has an
outflow aperture and at least two anchoring stays made of a
flexible material having memory and arranged concentrically around
the outflow aperture. The anchoring stays can be fed through the
footplate of the stapes at the oval window and anchor themselves
against the inner surface of the footplate. In further embodiments
of this configuration, the bulbous extension is fitted with a clip,
which anchors itself against the base of stapes. Another
configuration has the catheter, the bulbous extension, and the
stays enveloped in a removable tube, which has an internal diameter
corresponding to the outer diameter of the bulbous extension.
[0021] This embodiment of the catheter is very suitable for
attachment to the footplate of the stapes at the oval window. Also,
attachment of the catheter to the footplate is performed in a
conceivably simple manner. First, an aperture is made in the
footplate of the oval window. Then, the catheter with its bulbous
extension is anchored at the footplate of the oval window so that
the anchoring elements are fed through the aperture in the
footplate.
[0022] Due to the memory characteristics of the material of the
anchoring stays, they flex themselves outwards after they have been
inserted, by way of which the catheter is thereby anchored. The
optional enveloping tube extends the anchoring stays in an axial
direction and anchors the bulbous extension to the footplate of the
oval window using anchoring stays, and the anchoring stays are fed
through the opening in the footplate. As soon as the anchoring
stays have been fed through the footplate and have left the rigid
mantle of the enveloping tube, the anchoring stays flex according
to the memory characteristic of the material and anchor themselves
against the inner surface of the footplate. Subsequently, the
enveloping tube can be pulled out towards the rear and removed. It
is possible to remove the catheter by pulling it, because the metal
has the property of memory and has a flectional resistance lower
than the tensile resistance of the footplate.
[0023] In a third embodiment of the invention, one end of the
catheter is fitted with a conical body having a front outflow
aperture, whose minimum diameter is greater than the diameter of
the catheter tube. The body is fitted with at least two hook-like
anchoring elements bent backwards to its outer mantle, which
together with a front sub-section of the conical body can be fed
through the membrane of the endolymphatic sac, and anchor
themselves against the inner surface of the membrane of the
endolymphatic sac.
[0024] It is also easy to feed this kind of catheter through the
membrane of the endolymphatic sac and to anchor it against the
membrane of the endolymphatic sac.
[0025] In accordance with practical embodiments of the invention,
the coupling elements of the catheter are made of carbon material
or titanium oxide ceramic. The other parts of the catheter can be
made of silicon. These materials have proven to be particularly
suitable for implantation into the human body without affecting the
surrounding tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Other objects and features of the present invention will
become apparent from the following detailed description considered
in connection with the accompanying drawings. It is to be
understood, however, that the drawings are designed as an
illustration only and not as a definition of the limits of the
invention.
[0027] In the drawings, wherein similar reference characters denote
similar elements throughout the several views:
[0028] FIG. 1 shows a side view of a first embodiment of a catheter
according to the invention;
[0029] FIG. 2 shows a perspective view of a second embodiment of
the catheter according to the invention;
[0030] FIGS. 3 and 4 show a side view of a detail of the catheter
shown in FIG. 2;
[0031] FIG. 5 shows a schematic view of a third embodiment of the
catheter according to the invention;
[0032] FIG. 6 shows an enlarged perspective of the anatomical
features of the human inner ear; and
[0033] FIG. 7 shows a schematic view of a micro-dosage system used
in conjunction with the catheter shown in FIGS. 2 to 4, in position
in the human ear.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Referring now in detail to the drawings, the geometry of the
human inner ear 1 is explained, using FIG. 6 as an example. Ear 1
comprises the utricle 2, the ampulla of the lateral semicircular
canal 3, the saccule 4, the cochlear duct 5 and the endolymphatic
sac 6. The inner ear 1 is particularly demarcated by the footplate
7 of the stapes at the oval window 8, by the membrane 9 of the
round window 10 and by the membrane 11 of the endolymphatic sac 6.
An additional access route to the inner ear is provided by the
auditory tube 12.
[0035] For physiological reasons, the footplate 7 of the oval
window 8, the membrane 9 of the round window 10 as well as the
membrane 11 of the endolymphatic sac 6 are suitable for applying
medication to the inner ear 1. Also suitable is the basilar
membrane which is not depicted in FIG. 6, if an operation similar
to the Cochlear Implant Operation is going to be performed.
[0036] FIG. 1 depicts a first embodiment of a catheter 20 according
to the invention. Catheter 20 is fitted with a catheter tube 22,
only a section of which is depicted in FIG. 1. At the one end 24,
the catheter 20 is fitted with an outflow aperture 26. It is
through this outflow aperture 26 that the medication fed through
the catheter tube 26 can leave the catheter 20 and discharge into
the inner ear 1.
[0037] At the end 24 of catheter 20, an anchoring element 28 is
arranged for anchoring catheter 20 to membrane 9 of round window
10. Anchoring element 28 comprises a disc 30, which is arranged
across and encompassing catheter tube 22 and which is in contact
with membrane 9. Disc 30 is designed with two anchoring stays 34,
36 on its edge, which anchor themselves against overhanging osseous
border 37 of round window 10.
[0038] The one end 24 with outflow aperture 26 has a cannula point
38. Cannula point 38 can be made of metallic material, for example
V4A steel or titanium, and is connected to an electro-conductive
cable 40 as indicated in FIG. 1. Cable 40 can be used for applying
electrically induced stimulations to inner ear 1, or for recovering
electric responses from the inner ear.
[0039] Disc 30 can be made of silicon and can have a diameter of
0.7, 1.2, or 1.7 mm with a thickness of 0.2 mm. Cannula point 38
preferably has a diameter of 0.3 mm and a length of 0.5 mm.
Catheter tube 22 has an internal diameter of 0.3 mm, an outer
diameter of 0.7 mm and a length of up to approximately 200 mm, and
can be connected to a dosage system 96 still to be described.
Anchoring stays 34, 36 at edge 32 of disc 30 can be between 0.7 and
1.0 mm long.
[0040] Catheter 20 depicted in FIG. 1 can be attached at a
cochleostomy, i.e., at an artificially created aperture in the
inner ear. Here the bone of the spiral organ/cochlea is removed
using a drill and the inner bone membrane, the so called scala
timpani, is exposed across a large enough surface, about 2.times.2
mm in size. The scala timpani is a connective tissue membrane,
which surrounds the perilymph as the innermost layer. After
exposure, similar to the membrane 9 of round window 10, it can be
punctured and disc 30 with anchoring elements 34, 36 can be
anchored at the surrounding osseous border.
[0041] Disc 30 also prevents cannula point 38 from penetrating too
far into inner ear 1 and in so doing guarantees a maximum depth of
insertion. At the same time, disc 30 acts as a sealing element at
the inner ear 1 side. The maximum guaranteed depth of penetration
prevents damage to the basilar membrane or to other intracochlear
structures. Due to the minimal depth of insertion, development of
foreign body reactions and/or direct mechanical damage can be
avoided or at least considerably reduced.
[0042] In FIGS. 2-4, the second embodiment of catheter 50 is
depicted according to the invention. This catheter 50 has a bulbous
extension 52, which is arranged at the end 54 of the catheter 50.
Catheter 50 also has a catheter tube 56, only a section of which is
shown in FIGS. 2-4.
[0043] One outflow aperture 58 is arranged centrally at the one end
surface 56 of the bulbous extension 52, through which medication
applied into catheter 50 can be discharged. Several anchoring
elements 60 in the form of anchoring stays 62 made of a material
having memory are arranged concentrically around the outflow
aperture 58 of bulbous extension 56. These stays are designed so
that after being extended they spring back into their original
position, as shown in FIG. 4.
[0044] In order to be able to anchor catheter 50 into position at
footplate 7 of oval window 8 as shown in FIG. 2, footplate 7 is
pierced, then anchoring stays 62 are fed through this aperture in
footplate 7, after which they anchor themselves against the inside
of the footplate 7. In order to ease insertion of front end 54 of
catheter 50, an enveloping tube 64 can be used, which is indicated
in FIGS. 3 and 4. As shown in FIG. 3 the enveloping tube 64 covers
the bulbous extension 52 and the anchoring stays 62, so that they
can be extended axially forward.
[0045] If catheter 50 is placed at the opening of footplate 7 in
this way, then catheter 50 can be pushed forward toward the inner
ear. As soon as anchoring stays 62 have passed through the opening
at footplate 7 and emerge away from the area influenced by the
enveloping tube 64, they spring back due to their memory and anchor
themselves at the inside of footplate 7. After that, enveloping
tube 64 can be removed by pulling it out backwards.
[0046] Bulbous extension 52 can be made of silicon or from a
related material and has a diameter of 1 mm and a thickness of 0.6
mm. The inner lumen of bulbous extension 52 can correspond to the
inner lumen of catheter tube 52, i.e., approximately 0.4 mm.
[0047] Similar to catheter 20 in FIG. 1, catheter 50 can be fitted
with a cable 66, which ends directly at the end surface 56 of
bulbous extension 52, or it can be connected to an anchoring
element 62, if this is made of metallic material.
[0048] As shown in FIG. 2, bulbous extension 52 is fitted with a
clip 68, which can be made of platinum for example, and which
anchors itself at end 70 against one of the crura of the base of
the stapes 14.
[0049] A third embodiment of a catheter 80 according to the
invention is schematically depicted in FIG. 5. Catheter 80 is fed
into the endolymphatic sac 6 through membrane 11 of endolymphatic
sac 6. Catheter 80 has a catheter tube 82, of which only a section
is depicted in FIG. 5, as well as an end 84 with outflow aperture
86. Catheter 80 is also fitted with an anchoring element 88.
Catheter 80 is designed with end 84 as a conical body 90, which has
a minimum diameter greater than the diameter of catheter tube
82.
[0050] Hook-like anchoring stays 94 acting as anchoring elements 88
are attached to the mantle surface 92. These hooks are flexed with
their ends toward the inner surface of membrane 11, so that after
insertion into the aperture in the membrane 11, conical body 90 can
be pushed through with hook-like anchoring elements 94 at least
part way through the aperture in the membrane 11. This prevents
conical body 90 from slipping out from the aperture in membrane 11
by hook-like anchoring elements 94. Anchoring elements 94 are made
of silicon like body 90. In the embodiment shown, they have a
length of 0.3 mm and a diameter of 0.1 mm.
[0051] FIG. 7 schematically depicts the human ear 16 with the
eardrum 18, which is fitted with a catheter 50 as shown in FIGS.
2-4. A catheter tube 52 is connected to a micro-dosage system 96,
which can be implanted into the bony tissue 17 of ear 16. Catheter
tube 52 passes through the middle ear. Catheter 50 is connected to
the oval window 8 as shown in FIGS. 2-4.
[0052] The micro-dosage system 96 can have a drug reservoir, a
micro-pump and an IC control, none of which are depicted. This
releases a programmed amount of medication via catheter tube 52
into the inner ear 1. Micro-dosage system 96 also has a tube 98
emerging at the body outer mantle, through which medication can be
supplied to the micro-dosage system 96. It is also possible for the
medication to be transcutaneously fed into micro-dosage system 96
via a syringe.
[0053] Accordingly, while only a few embodiments of the present
invention have been shown and described, it is obvious that many
changes and modifications may be made thereunto without departing
from the spirit and scope of the invention.
* * * * *