U.S. patent application number 10/731869 was filed with the patent office on 2004-09-09 for modular implantable medical device.
Invention is credited to Singhal, Ruchika, Skime, Robert M., Wahlstrand, Carl D..
Application Number | 20040176818 10/731869 |
Document ID | / |
Family ID | 32512690 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040176818 |
Kind Code |
A1 |
Wahlstrand, Carl D. ; et
al. |
September 9, 2004 |
Modular implantable medical device
Abstract
An implantable medical device includes a plurality of separately
housed and flexibly interconnected modules. A first module includes
a control electronics within a first housing, and may be coupled to
a second module that includes a second housing by a flexible
interconnect member. In some embodiments, an overmold, which may be
flexible, at least partially encapsulates the first and second
housings. The second module may be a power source module that
includes a power source, such as a rechargeable battery, within the
second housing. The implantable medical device may also include a
third module, such as a recharge module that includes a coil within
a third housing. The overmold may at least partially encapsulate
the third housing, or the third module may be tethered to the
overmold by a flexible tether member. A flexible interconnect
member and/or flexible overmold may allow multiples degrees of
freedom of movement between modules of an implantable medical
device.
Inventors: |
Wahlstrand, Carl D.; (Lino
Lakes, MN) ; Singhal, Ruchika; (Minneapolis, MN)
; Skime, Robert M.; (Coon Rapids, MN) |
Correspondence
Address: |
SHUMAKER & SIEFFERT, P. A.
8425 SEASONS PARKWAY
SUITE 105
ST. PAUL
MN
55125
US
|
Family ID: |
32512690 |
Appl. No.: |
10/731869 |
Filed: |
December 9, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60431854 |
Dec 9, 2002 |
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60471262 |
May 16, 2003 |
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60503945 |
Sep 20, 2003 |
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60503946 |
Sep 20, 2003 |
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60507857 |
Oct 1, 2003 |
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Current U.S.
Class: |
607/45 |
Current CPC
Class: |
A61N 1/37514 20170801;
A61N 1/37518 20170801; A61N 1/3605 20130101; A61N 1/3758 20130101;
A61N 1/3754 20130101 |
Class at
Publication: |
607/045 |
International
Class: |
A61N 001/08 |
Claims
1. An implantable medical device comprising: a first module that
includes control electronics within a first housing; a second
module that includes a second housing; and an overmold that at
least partially encapsulates the first and second housings.
2. The implantable medical device of claim 1, wherein the second
module includes a power source within the second housing that
provides power to the first module.
3. The implantable medical device of claim 2, wherein the power
source is rechargeable.
4. The implantable medical device of claim 3, further comprising a
recharge coil that inductively receives energy to recharge the
power source.
5. The implantable medical device of claim 4, wherein the recharge
coil is located within the overmold and substantially encircles the
first and second modules.
6. The implantable medical device of claim 4, further comprising a
third module that includes a third housing that houses the recharge
coil.
7. The implantable medical device of claim 6, wherein the overmold
at least partially encapsulates the third module.
8. The implantable medical device of claim 7, wherein the first,
second and third modules are positioned within the overmold in one
of a triangular configuration and a linear configuration.
9. The implantable medical device of claim 6, wherein the third
module is located outside of the overmold, the implantable medical
device further comprising a flexible tether member that connects
the third module to the overmold.
10. The implantable medical device of claim 9, wherein the flexible
tether member comprises a helix.
11. The implantable medical device of claim 1, wherein the overmold
completely encapsulates the first and second modules.
12. The implantable medical device of claim 1, wherein the overmold
does not encapsulate a portion of each of the first and second
modules, and each of the portions is proximate to a cranium of a
patient when the implantable medical device is implanted on the
cranium.
13. The implantable medical device of claim 1, wherein the overmold
is flexible.
14. The implantable medical device of claim 1, wherein the overmold
comprises silicone.
15. The implantable medical device of claim 1, wherein the overmold
comprises at least two materials.
16. The implantable medical device of claim 1, further comprising a
flexible interconnect member to couple the first and second
modules.
17. The implantable medical device of claim 16, wherein the
interconnect member is flexible in a plurality of directions and
allows the first and second modules to have a plurality of degrees
of freedom of movement relative to each other.
18. The implantable medical device of claim 1, wherein each of the
first and second housings are substantially cylindrical.
19. The implantable medical device of claim 1, further comprising:
a lead connection module formed within the overmold to receive one
of a lead that includes an electrode and a lead extension that is
coupled to the lead; and a conductor that extends from the lead
connection module to the first module, wherein the first housing
comprises a hermetic feedthrough to receive the conductor and the
conductor electrically couples the electrode to the first
module.
20. The implantable medical device of claim 1, wherein the first
module comprises a therapy delivery circuit to deliver electrical
stimulation to a patient, and the control electronics control the
delivery of electrical stimulation by the therapy delivery
circuit.
21. The implantable medical device of claim 1, wherein the overmold
is shaped for implantation on a cranium of a patient.
22. The implantable medical device of claim 1, wherein the
implantable medical device is flexible such that a shape of the
implantable medical device is capable of being manipulated.
23. An implantable medical device comprising: a first module that
includes control electronics housed within a first housing; a
second module that includes a power source that provides power to
the first module housed within a second housing; and an
interconnect member that flexibly couples the first and second
modules.
24. The implantable medical device of claim 23, wherein the power
source is rechargeable.
25. The implantable medical device of claim 24, further comprising
a recharge coil that inductively receives energy to recharge the
power source.
26. The implantable medical device of claim 25, wherein the
recharge coil is located within an overmold and substantially
encircles the first and second modules.
27. The implantable medical device of claim 25, further comprising
a third module that includes a third housing that houses the
recharge coil.
28. The implantable medical device of claim 27, wherein an overmold
at least partially encapsulates the third module.
29. The implantable medical device of claim 28, wherein the first,
second and third modules are positioned within the overmold in one
of a triangular configuration and a linear configuration in which
the modules are positioned substantially along a common axis.
30. The implantable medical device of claim 27, wherein the third
module is located outside of the overmold, the implantable medical
device further comprising a flexible tether member that connects
the third module to the overmold.
31. The implantable medical device of claim 30, wherein the
flexible tether member comprises a helix.
32. The implantable medical device of claim 23, wherein the
interconnect member is flexible in a plurality of directions and
allows the first and second modules to have a plurality of degrees
of freedom of movement relative to each other.
33. The implantable medical device of claim 32, wherein the
interconnect member allows the first and second modules to have at
least three degrees of freedom of movement relative to each
other.
34. The implantable medical device of claim 33, wherein the
interconnect member is hermetic.
35. The implantable medical device of claim 23, wherein each of the
first and second housings are substantially cylindrical.
36. The implantable medical device of claim 23, further comprising:
a lead connection module formed within an overmold to receive one
of a lead that includes an electrode and a lead extension that is
coupled to the lead; and a conductor that extends from the lead
connection module to the first module, wherein the first housing
comprises a hermetic feedthrough to receive the conductor and the
conductor electrically couples the electrode to the first
module.
37. The implantable medical device of claim 23, wherein the first
module comprises a therapy delivery circuit to deliver electrical
stimulation to a patient, and the control electronics control the
delivery of electrical stimulation by the therapy delivery
circuit.
38. The implantable medical device of claim 23, wherein the
implantable medical device is flexible such that a shape of the
implantable medical device is capable of being manipulated.
39. An implantable medical device comprising: a first module that
includes control electronics housed within a first housing; a
second module that includes a power source that provides power to
the first module housed within a second housing; and a hermetic
interconnect member that flexibly couples the first and second
modules, wherein the interconnect member is flexible in a plurality
of directions and allows the first and second modules to have a
plurality of degrees of freedom of movement relative to each
other.
40. The implantable medical device of claim 39, wherein the
interconnect member allows the first and second modules to have at
least three degrees of freedom of movement relative to each
other.
41. The implantable medical device of claim 39, wherein the
implantable medical device is flexible such that a shape of the
implantable medical device is capable of being manipulated.
42. An implantable medical device comprising: a first module
comprising control electronics and a therapy delivery circuit
housed within a first housing, wherein the control electronics
control delivery of stimulation by the therapy delivery circuit; a
second module comprising a power source within a second housing
that provides power to the control electronics and the therapy
delivery circuit; an interconnect member that flexibly couples the
first and second modules and includes a conductor for delivery
power from the power source to the control electronics and the
therapy delivery circuit; and a flexible overmold that at least
partially encapsulates the first and second housings.
43. The implantable medical device of claim 42, wherein the power
source is rechargeable.
44. The implantable medical device of claim 43, further comprising
a recharge coil that inductively receives energy to recharge the
power source.
45. The implantable medical device of claim 44, wherein the
recharge coil is located within the flexible overmold and
substantially encircles the first and second modules.
46. The implantable medical device of claim 44, further comprising
a third module that includes a third housing that houses the
recharge coil.
47. The implantable medical device of claim 46, wherein the
flexible overmold at least partially encapsulates the third
module.
48. The implantable medical device of claim 47, wherein the first,
second and third modules are positioned within the overmold in one
of a triangular configuration and a linear configuration in which
the modules are positioned substantially along a common axis.
49. The implantable medical device of claim 46, wherein the third
module is located outside of the overmold, the implantable medical
device further comprising a flexible tether member that connects
the third module to the overmold.
50. The implantable medical device of claim 49, wherein the
flexible tether member comprises a helix.
51. The implantable medical device of claim 42, wherein the
interconnect member is flexible in a plurality of directions and
allows the first and second modules to have a plurality of degrees
of freedom of movement relative to each other.
52. The implantable medical device of claim 42, further comprising:
a lead connection module formed within the overmold to receive one
of a lead that includes an electrode and a lead extension that is
coupled to the lead; and a conductor that extends from the lead
connection module to the first module, wherein the first housing
comprises a hermetic feedthrough to receive the conductor and the
conductor electrically couples the electrode to the first
module.
53. The implantable medical device of claim 42, wherein the
overmold is shaped for implantation on a cranium of a patient.
54. The implantable medical device of claim 42, wherein the
implantable medical device is flexible such that a shape of the
implantable medical device is capable of being manipulated.
55. The implantable medical device of claim 42, wherein the therapy
delivery circuit comprises a pulse generator.
56. An implantable medical device comprising: control electronics
and a rechargeable power source that provides power for the control
electronics within a first housing; a recharge coil within a second
housing that inductively receives energy to recharge the power
source; and a flexible tether member that connects the first and
second housings.
57. The implantable medical device of claim 56, wherein the
flexible tether member comprises a helix.
Description
[0001] This application claims the benefit of:
[0002] 1. U.S. Provisional Application entitled "CRANIAL
NEUROSTIMULATOR AND METHOD," Serial No. 60/431,854, (Attorney
Docket No. P-10891.00), filed on Dec. 9, 2002;
[0003] 2. U.S. Provisional Application entitled "IMPLANTABLE
CRANIAL MEDICAL DEVICES AND METHODS," Serial No. 60/471,262,
(Attorney Docket No. P-11462.00), filed on May 16, 2003;
[0004] 3. U.S. Provisional Application entitled "IMPLANTABLE
CRANIAL MEDICAL DEVICES AND METHODS," Serial No. 60/503,945,
(Attorney Docket No. P-11696.00), filed on Sep. 20, 2003;
[0005] 4. U.S. Provisional Application entitled "IMPLANTABLE
CRANIAL MEDICAL DEVICES AND METHODS," Serial No. 60/503,946,
(Attorney Docket No. P-11697.0), filed on Sep. 20, 2003; and
[0006] 5. U.S. Provisional Application entitled "Thin Neuro
Stimulation System, Device and Method," Serial No. 60/507,857,
(Attorney Docket No. P-20211.00), filed on Oct. 1, 2003.
[0007] The entire content of each of these U.S. Provisional
Applications is incorporated herein by reference.
[0008] The following co-pending and commonly-assigned U.S. patent
applications, filed on even date herewith, are also incorporated
herein by reference in their entirety:
[0009] 1. U.S. patent application entitled "CONCAVITY OF AN
IMPLANTABLE MEDICAL DEVICE," to Carl D. Wahlstrand et al., filed
Dec. 9, 2003, assigned Attorney Docket No.:
1023-336US01/P-11800.00;
[0010] 2. U.S. patent application entitled "IMPLANTATION OF
LOW-PROFILE IMPLANTABLE MEDICAL DEVICE," to Ruchika Singhal et al.,
filed Dec. 9, 2003, assigned Attorney Docket No.:
1023-330US01/P-11795.00;
[0011] 3. U.S. patent application entitled "COUPLING MODULE OF A
MODULAR IMPLANTABLE MEDICAL DEVICE," to Darren A. Janzig et al.,
filed Dec. 9, 2003, assigned Attorney Docket No.:
1023-331US01/P-11796.00;
[0012] 4. U.S. patent application entitled "OVERMOLD FOR A MODULAR
IMPLANTABLE MEDICAL DEVICE," to Ruchika Singhal et al., filed Dec.
9, 2003, assigned Attorney Docket No.: 1023-332US01/P-11798.00;
[0013] 5. U.S. patent application entitled "REDUCING RELATIVE
INTERMODULE MOTION IN A MODULAR IMPLANTABLE MEDICAL DEVICE," to
Carl D. Wahlstrand et al., filed Dec. 9, 2003, assigned Attorney
Docket No.: 1023-333US01/P-11797.00;
[0014] 6. U.S. patent application entitled "LEAD CONNECTION MODULE
OF A MODULAR IMPLANTABLE MEDICAL DEVICE," to Ruchika Singhal et
al., filed Dec. 9, 2003, assigned Attorney Docket No.:
1023-334US01/P-11799.00;
[0015] 7. U.S. patent application entitled "LOW-PROFILE IMPLANTABLE
MEDICAL DEVICE," to Darren A. Janzig et al., filed Dec. 9, 2003,
assigned Attorney Docket No.: 1023-335US01/P-11801.00; and
[0016] 8. U.S. patent application entitled "MODULAR IMPLANTABLE
MEDICAL DEVICE," to Carl D. Wahlstrand et al., filed Dec. 9, 2003,
assigned Attorney Docket No.: P-20542.00.
TECHNICAL FIELD
[0017] The invention relates to medical devices, and more
particularly, to implantable medical devices that deliver therapy
to and/or monitor a patient.
BACKGROUND
[0018] Depending on the application for which they are implanted in
a patient, implantable medical devices (IMDs) may include a variety
of electrical and/or mechanical components. Typically, an IMD
includes a rigid housing that houses all of its components, which
are generally fragile, to protect the components from forces to
which they would otherwise be exposed when implanted within the
human body. In order to avoid potentially harmful interactions
between the components and bodily fluids, e.g., corrosion, IMD
housings are typically hermetically sealed. Many IMD housings are
fabricated from Titanium because of its desirable rigidity and
biocompatibility.
[0019] The size and shape of an IMD housing is dependant on the
sizes and shapes of the components of the IMD. Large components
common to most IMDs include a battery, a telemetry coil, and a
circuit board that carries digital circuits, e.g., integrated
circuit chips and/or a microprocessor, and analog circuit
components. Attempts have been made to reduce the size of the IMD
housing by reducing the size of these components, changing the
shape of these components, and organizing these components within
the IMD housing to avoid empty space within the housing. Despite
these efforts to reduce the size of IMD housings, the size, shape
and rigidity of IMD housings still greatly limits the locations
within the human body where an IMD can be practically
implanted.
[0020] Due to these limitations, an IMD is typically implanted
within the abdomen, upper pectoral region, or subclavicular region
of a patient. Leads or catheters must be used in order to deliver
therapy or monitor a physiological parameter at a location of the
body other than where the IMD is implanted. Implantation and
positioning of leads and catheters can be difficult and
time-consuming from the perspective of a surgeon, particularly
where the IMD is located a significant distance from the treatment
or monitoring site. Moreover, the increased surgical time,
increased surgical trauma, and increased amount of implanted
material associated with the use of leads and catheters can
increase the risk to the patient of complications associated with
the implantation of an IMD.
[0021] For example, IMDs that are used to treat or monitor the
brain, e.g., to deliver deep brain stimulation (DBS) therapy, are
implanted some distance away from the brain, e.g., within the
subclavicular region of patients. The long leads that connect the
implantable medical device to electrodes implanted within the brain
require tunneling under the scalp and the skin of the neck, thereby
requiring increased surgery and a prolonged amount of time under
general anesthesia during the implant procedure, as well as
increased recovery time. In some cases, tunneling the leads under
the scalp and skin of the neck requires an additional surgical
procedure under general anesthesia. The lengthy tract along the
leads is more susceptible to infection, and the leads can erode the
overlying scalp, forcing removal so that the scalp can heal.
Further, the long leads running under the scalp and through the
neck are more susceptible to fracture due to torsional and other
forces caused by normal head and neck movements.
SUMMARY
[0022] In general, the invention is directed to an implantable
medical device that includes a plurality of separately housed and
flexibly interconnected modules. One of the modules is a control
module that includes control electronics within a first housing.
The control electronics control the functioning of the implantable
medical device, and may include a processor.
[0023] A second module may be a power source module that includes a
power source within a second housing. The power source provides
power to the first module, e.g., to the control electronics. The
power source may be a rechargeable power source, such as a
rechargeable battery or a capacitor.
[0024] The first and second modules may be coupled by a flexible
interconnect member, which may be hermetic. In various embodiments,
the flexible interconnect member may include, for example,
conductors to electrically couple the first and second modules. The
flexible interconnect member may be flexible in more than one
direction, providing the first and second modules with multiple
degrees of freedom of motion with respect to each other including,
in some embodiments, rotational motion. In exemplary embodiments,
the flexible interconnect member provides at least three degrees of
motion.
[0025] In some embodiments, the implantable medical device includes
an overmold that at least partially encapsulates the first and
second housings. In embodiments in which the overmold does not
completely encapsulate the first and second housings, the overmold
may encapsulate an upper portion of the housings. Where such an
implantable medical device is implanted on the cranium, lower
portions of the housings may contact the cranium. In some
embodiments, the overmold is flexible, may be comprised of
silicone, and may include at least two materials. Together, a
flexible overmold and flexible interconnect member may allow the
modular implantable medical device to be manipulated during
implantation to substantially conform to cranium.
[0026] The implantable medical device may also include a third
module, such as a recharge module that includes a coil within a
third housing. In such embodiments, the coil inductively receives
energy to recharge the power source within the second module. The
overmold may at least partially encapsulate the third housing, or
the third module may be tethered to the overmold by a tether member
that allows the third module freedom of motion relative to the
overmold such that the third module may be placed at a selected
location some significant distance form the overmold and the other
modules. The implantable medical device may include any number of
modules in addition to the control module, and the additional
modules are not limited to power source modules and/or recharge
modules.
[0027] In exemplary embodiments, the implantable medical device is
configured for implantation on the cranium of a patient. Further,
the implantable medical device may comprise a neurostimulator, and
the control module may include therapy delivery circuitry for
delivery of stimulation to the brain of a patient. The implantable
medical device may include a lead connection module formed within
the overmold to receive a lead or lead extension.
[0028] In one embodiment, the invention is directed to an
implantable medical device that includes a first module and a
second module. The first module includes control electronics within
a first housing. The second module includes a second housing. The
implantable medical device further includes an overmold that at
least partially encapsulates the first and second housings.
[0029] In another embodiment, the invention is directed to an
implantable medical device that includes a first module and a
second module. The first module includes control electronics within
a first housing. The second module includes a power source that
provides power to the first module housed within a second housing.
The implantable medical device further includes an interconnect
member that flexibly couples the first and second modules.
[0030] In another embodiment, the invention is directed to an
implantable medical device that includes a first module and a
second module. The first module includes control electronics housed
within a first housing, and the second module that includes a power
source that provides power to the first module housed within a
second housing. The implantable medical device further includes a
hermetic interconnect member that flexibly couples the first and
second modules. The interconnect member is flexible in a plurality
of directions and allows the first and second modules to have a
plurality of degrees of freedom of movement relative to each
other.
[0031] In another embodiment, the invention is directed to an
implantable neurostimulator for delivering stimulation to a brain
of a patient that includes a first module and second module. The
first module includes control electronics and a therapy delivery
circuit housed within a first housing. The control electronics
control delivery of stimulation by the therapy delivery circuit.
The second module includes a power source within a second housing
that provides power to the control electronics and the therapy
delivery circuit. The implantable neurostimulator further includes
an interconnect member that flexibly couples the first and second
modules and includes a conductor for delivery power from the power
source to the control electronics and the therapy delivery circuit,
and a flexible overmold that at least partially encapsulates the
first and second housings.
[0032] In another embodiment, the invention is directed to an
implantable medical device that includes control electronics and a
rechargeable power source that provides power for the control
electronics within a first housing. The implantable medical device
further includes a recharge coil within a second housing that
inductively receives energy to recharge the power source, and a
flexible tether member that connects the first and second
housings.
[0033] The invention may be capable of providing one or more
advantages. For example, by distributing components of an
implantable medical device amongst modules rather than including
them within a single, rigid housing, the implantable medical device
may be shaped and configured for implantation at locations within
the human body for which implantation of conventional implantable
medical devices is deemed undesirable. A flexible interconnect
member and/or flexible overmold may allow multiples degrees of
freedom of movement between modules of an implantable medical
device, allowing the implantable medical device to conform to such
areas, and in particular embodiments, to conform to surfaces within
the human body such as the surface of the cranium. The flexible
interconnect member and/or flexible overmold may allow the
implantable medical device to be manipulated during implantation to
conform to craniums with various sizes and shapes.
[0034] Because a modular implantable medical device according to
the invention can be implanted on the cranium of a patient rather
then more remotely from the brain, such as within a subclavicular
region of the patient, the problems associated with the use of long
leads needed to allow a remotely implanted medical device to access
the brain may be diminished or avoided. Distribution of components
of the implantable medical device within modules may reduce the
effective thickness of the implantable medical device on the
cranium making the implantable medical device less noticeable,
e.g., more cosmetically appealing, when implanted on the cranium
beneath the scalp of the patient. Further, in embodiments, that
include an overmold, the overmold may be shaped to make the
implantable medical device more cosmetically appealing and
comfortable, and also more clinically acceptable, such as by
including tapered edges that reduce the likelihood of skin erosion
on the scalp over the device.
[0035] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other embodiments of the invention will be apparent from the
description and drawings, and from the claims.
BRIEF DESCRIPTION OF DRAWINGS
[0036] FIG. 1 is a conceptual diagram illustrating an example
modular implantable medical device implanted on the cranium of a
patient.
[0037] FIG. 2 is a top-view diagram further illustrating the
modular implantable medical device of FIG. 1 implanted on the
cranium of the patient.
[0038] FIG. 3 is a top-view diagram further illustrating the
modular implantable medical device of FIG. 1.
[0039] FIG. 4 is top-view diagram illustrating a recharge module of
the modular implantable medical device of FIG. 1.
[0040] FIG. 5 is a block diagram illustrating a control module of
the modular implantable medical device of FIG. 1.
[0041] FIGS. 6A and 6B are top-view diagrams illustrating other
example modular implantable medical devices.
[0042] FIG. 7 is a block diagram illustrating a power source module
of the modular implantable medical device of FIG. 6B.
[0043] FIGS. 8A and 8B are cross-sectional diagrams illustrating
two example configurations of the modular implantable medical
device of FIG. 6B.
[0044] FIGS. 9A and 9B are top-view diagrams illustrating another
example modular implantable medical device that include a tethered
recharge module.
[0045] FIGS. 10, 11A, 11B and 12 are conceptual diagrams
illustrating other example modular implantable medical devices.
[0046] FIG. 13 is a conceptual diagram illustrating a stacked
circuit board.
[0047] FIGS. 14A and 14B are top-view diagrams illustrating other
modular implantable medical devices.
DETAILED DESCRIPTION
[0048] FIG. 1 is a conceptual diagram illustrating an example
modular implantable medical device (IMD) 10 implanted on the
cranium 12 of a patient 14. As will be described in greater detail
below, IMD 10 comprises a plurality of separately housed and
flexibly interconnected modules. By distributing components of IMD
10 amongst modules rather than including them within a single,
rigid housing, the implantable medical device may be shaped and
configured for implantation at locations within patient 14 for
which implantation of conventional IMDs is deemed undesirable.
Further, the flexibility of the interconnection between modules of
IMD 10 may allow multiples degrees of freedom of movement between
the modules, which in turn may allow the implantable medical device
to conform to such areas, and in particular embodiments, to conform
to surfaces within patient 14 such as the surface of cranium
12.
[0049] In the illustrated example, modular IMD 10 is coupled to two
leads 16A and 16B (collectively "leads 16") that extend through
holes within cranium 12, and into the brain of patient 14. In
exemplary embodiments, each of leads 16 carries a plurality of
electrodes, and IMD 10 delivers stimulation to the brain of patient
14 via the electrodes. Modular IMD 10 may be coupled to any number
of leads 16, and in some embodiments is not coupled to any leads
16.
[0050] Because modular IMD 10 can be implanted on cranium 12 of
patient 14 rather then more remotely from the brain of patient 14,
such as within an subclavicular region of patient 14, the problems
associated with the use of long leads needed to allow a remotely
implanted IMDs to access the brain may be diminished or avoided.
These problems include the requirement of tunneling under the scalp
and the skin of the neck, increased surgery and recovery time, an
additional procedure under general anesthesia, risk of infection or
skin erosion along the track through which the leads are tunneled,
and risk of lead fracture due to torsional and other forces caused
by normal head and neck movements.
[0051] FIG. 2 is a top-view diagram further illustrating modular
IMD 10 implanted on cranium 12 of the patient 14. In order to
implant modular IMD 10 on cranium 12, an incision 20 is made
through the scalp of patient 14, and a resulting flap of skin is
pulled back to expose the desired area of cranium 12. The incision
may, as shown in FIG. 2, be generally shaped like a "C." Such an
incision is commonly referred to as a "C-flap" incision.
[0052] Holes 22A and 22B (collectively "holes 22") are drilled
through cranium 12, and leads 16 are inserted through holes 22 and
into the brain of patient 14. Caps may be placed over holes 22 as
is known in the art. Leads 16 are connected to modular IMD 10,
either directly or via a lead extension, and modular IMD 10 is
placed at least partially within a pocket formed using a hand or a
tool beneath the scalp behind holes 22.
[0053] Once positioned as desired on cranium 12 within the pocket,
modular IMD 10 may then be fixed to cranium 12 using an attachment
mechanism such as bone screws. The skin flap may be closed over
modular IMD 10, and the incision may be stapled or sutured. The
location on cranium 12 at which IMD 10 is illustrated as implanted
in FIG. 2 is merely exemplary, and IMD 10 can be implanted anywhere
on the surface of cranium 12. Further details regarding exemplary
techniques for implanting IMD 10 on the cranium may be found in a
commonly-assigned U.S. patent application entitled "IMPLANTATION OF
LOW-PROFILE IMPLANTABLE MEDICAL DEVICE," assigned Attorney Docket
No.: 1023-330US01/P-11795.00.
[0054] Because of the flexibility provided by interconnect members
and/or an overmold of modular IMD 10, the IMD may be manipulated
during implantation such that it conforms to cranium 12. For
example, in some embodiments a clinician can manipulate modular IMD
10 into conformance with cranium 12 while IMD 10 is on cranium 12
and fix modular IMD 10 into place using bone screws or the like. In
other embodiments, the clinician may manipulate modular IMD 10 into
conformance with cranium 12 with IMD 10 on and/or off of cranium
12, and IMD 10 may substantially retain the form into which it is
manipulated.
[0055] As mentioned above, modular IMD 10 may deliver stimulation
to the brain of patient 14 to, for example, provide deep brain
stimulation (DBS) therapy, or to stimulate the cortex of the brain.
Cortical stimulation may involve stimulation of the motor cortex.
Modular IMD 10 may be used to treat any nervous system disorder
including, but not limited to, epilepsy, pain, psychological
disorders including mood and anxiety disorders, movement disorders
(MVD), such as, but not limited to, essential tremor, Parkinson's
disease, and neurodegenerative disorders.
[0056] However, modular IMD 10 is not limited to delivery of
stimulation to the brain of patient, and may be employed with leads
16 deployed anywhere in the head or neck including, for example,
leads deployed on or near the surface of the skull, leads deployed
beneath the skull such as near or on the dura mater, leads placed
adjacent cranial or other nerves in the neck or head, or leads
placed directly on the surface of the brain. Moreover, modular IMD
10 is not limited to implantation on cranium 12. Indeed, modular
IMD 10 may be implanted anywhere within patient 14. For example,
modular IMD 10 can be implanted within the neck of patient 14, and
deliver stimulation to the vagus nerve or the cervical region of
the spinal cord.
[0057] Modular IMD 10 may alternatively be implanted within a
pectoral region or the abdomen of patient 14 to act as a
diaphragmatic pacer, or to provide any of the monitoring and
therapy delivery functions known in the art to be associated with
cardiac pacemakers. Further, modular IMD 10 may be implanted in the
upper buttock region and deliver spinal cord, urological or
gastrological stimulation therapy, or may be configured to be
implanted within the periphery, e.g., limbs, of patient 14 for
delivery of stimulation to the muscles and/or peripheral nervous
system of patient 14. As is the case with cranium 12, the
modularity of IMD 10 may enable implantation at some of these
example locations for which implantation of conventional IMDs is
generally deemed undesirable.
[0058] Modular IMD 10 is not limited to embodiments that deliver
stimulation. For example, in some embodiments modular IMD 10 may
additionally or alternatively monitor one or more physiological
parameters and/or the activity of patient 14, and may include
sensors for these purposes. Where a therapy is delivered, modular
IMD 10 may operate in an open loop mode (also referred to as
non-responsive operation), or in a closed loop mode (also referred
to as responsive). Modular IMD 10 may also provide warnings based
on the monitoring.
[0059] As discussed above, the ability of a modular IMD 10
according to the invention to be implanted close to a region within
patient 14 to be monitored enables the use of shorter leads 16.
Shorter leads 16 may advantageously improve the accuracy of such
sensors by reducing noise attributable to leads 16. Shorter leads
16 may also advantageously reduce the negative affects of imaging
techniques such as magnetic resonance imaging "MRI" on a person
implanted with IMD 10.
[0060] Further, in some embodiments modular IMD 10 can additionally
or alternatively deliver a therapeutic agent to patient 14, such as
a pharmaceutical, biological, or genetic agent. Modular IMD 10 may
be coupled to a catheter, and may include a pump to deliver the
therapeutic agent via the catheter.
[0061] FIG. 3 is a top-view diagram further illustrating modular
IMD 10. In the illustrated embodiment, modular IMD 10 includes
three modules: a control module 30, a power source module 32, and a
recharge module 34. As shown in FIG. 3, modules 30, 32 and 34
include separate housings 36, 38 and 40, respectively.
[0062] Control module 30 includes control electronics within the
housing, e.g., electronics that control the monitoring and/or
therapy delivery functions of modular IMD 10, such as a
microprocessor. Control module 30 may also include circuits for
telemetry communication with external programmers or other devices
within the housing. Housing 36 of control module 30 may be hermetic
in order to protect the control electronics therein, and in
exemplary embodiments is formed of a rigid material, such as
titanium, stainless steel, or a ceramic. In exemplary embodiments,
housing 36 is a low-profile, concave housing, and techniques for
arranging components of control module 30 to enable such a
low-profile, concave housing are described in greater detail in a
commonly-assigned U.S. patent application entitled "LOW-PROFILE
IMPLANTABLE MEDICAL DEVICE," assigned Attorney Docket No.:
1023-335US01/P-11801.00.
[0063] Power source module 32 includes a power source within
housing 38. The power source provides power for components of other
modules, such as the control electronics within control module 30.
The power source may be any power source suitable for use within an
IMD, such as one or more batteries, capacitors, solar cells, fuel
cells, nuclear cells, or any combination thereof. In an exemplary
embodiment, the power source comprises a rechargeable Lithium Ion
battery, which may have a thin wound coil construction, or a foil
pack or other non-coiled construction to more easily fit within
housing 38 which may be less than 5 millimeters thick with an
approximately one square inch surface area. Housing 38 may be
hermetic, and may be formed of titanium, stainless steel, or a
ceramic. Power source module 32 may include an insulator within
housing 38 to isolate housing 38 from the power source.
[0064] Where the power source includes a rechargeable power, such
as a rechargeable battery and/or a capacitor, modular IMD 10 may
include recharge module 34. As shown in FIG. 4, recharge module 34
includes a recharge coil 42 within housing 40. Recharge coil 42
inductively receives energy from an external recharging unit (not
illustrated) through the skin of patient 14 to recharge the power
source. Recharge coil 42 may be formed of windings of copper or
another highly conductive material. Housing 40 need not be
hermetic, and may be formed of materials such as silicone, polymers
and ceramics.
[0065] Housings 36, 38 and 40 may have any shape, including the
round, coin shape and rectangular shapes with rounded edges
illustrated in FIG. 3. Further, one or more surfaces of one or more
of housings 36, 38 and 40 may be concave along at least one axis,
and preferably two axes. Further details regarding the concavity of
housings 36, 38 and 40 may be found in a commonly-assigned U.S.
patent application entitled "CONCAVITY OF AN IMPLANTABLE MEDICAL
DEVICE," assigned Attorney Docket No.: 1023-336US01/P-11800.00.
[0066] Modules 30, 32 and 34 can be configured in a variety of
ways, and the configuration illustrated in FIG. 3 is merely
exemplary. Additional exemplary configurations are illustrated in
FIGS. 6A, 6B, 9A, 9B, 10, 11A, 11B, 12, 14A and 14B, which are
discussed below. Further, modular IMD 10 can include any number of
modules, and may include other types of modules instead of or in
addition to a power source module 32 and a recharge module 34. For
example, modular IMD 10 can include additional power source
modules, modules that include additional memory that is accessible
by the control electronics within control module 30, modules that
include reservoirs for storing therapeutic agents and pumps for
delivering therapeutic agents to patient 14, and modules that
include sensors sensing physiological parameters, such as pressures
or blood flows, or the activity level of patient 12.
[0067] Power source module 32 is coupled to control module 30 by a
flexible interconnect member 44, which encloses a conductor that
allows transmission of energy from the power source of power source
module 32 to components such as the control electronics within
control module 30. In embodiments where energy is transferred via a
DC voltage on the conductor, it may be necessary to make flexible
interconnect member 44 hermetic. In embodiments in which flexible
interconnect member 44 is hermetic, flexible interconnect member 44
may be made of titanium or stainless steel. In embodiments where
energy is transferred via a charge-balance voltage on the
conductor, such as an AC voltage, flexible interconnect member 44
need not be hermetic, and may be made of any material including
silicone or various polymers.
[0068] In the illustrated embodiment, the control electronics of
control module 30 regulates the recharging and discharging of the
power source within power source module 32. Consequently, as shown
in FIG. 3, recharge module 34 is coupled to control module 30 by a
flexible interconnect member 46 that encloses a conductor that
allows transmission of energy inductively received by coil 42 to
control module 30. Because the energy is transferred on the
conductor via a charge-balanced voltage, flexible interconnect
member 46 need not be hermetic, and may be made of any material
including titanium, stainless steel, ceramics, silicone or various
polymers.
[0069] Interconnect members 44 and 46 are flexible. In some
embodiments, as indicated above, interconnect members 44 and 46 are
made of a flexible material such as silicone or a flexible polymer.
In embodiments where flexible member 44 is hermetic and made of
substantially less flexible material, such as titanium or stainless
steel, the flexibility of interconnect member 44 is provided by the
configuration and/or construction of flexible interconnect member
44.
[0070] Interconnect member 44 is flexible in a plurality of
directions to provide modules 30 and 32 with multiple degrees of
freedom of motion with respect to each other. In exemplary
embodiments, interconnect member 44 provides at least three degrees
of motion, and the degrees of motion provided include rotational
motion. Further details regarding the configuration and/or
construction of interconnect member 44 to provide such flexibility
may be found in a commonly-assigned U.S. patent application
entitled "COUPLING MODULE OF MODULAR IMPLANTABLE MEDICAL DEVICE,"
assigned Attorney Docket No.: 1023-331US01/P-11796.00.
[0071] As shown in FIG. 3, modular IMD 10 includes an overmold 48,
which may be flexible. In the illustrated embodiment, overmold 48
at least partially encapsulates each of housings 36, 38 and 40.
Overmold 48 integrates modules 30, 32 and 34 into a desired form
factor, but, where flexible, allows relative intermodule motion. In
some embodiments, overmold 48 incorporates mechanical features to
restrict intermodule motion to certain directions or within certain
ranges. Overmold 48 may be made from silicone, and is some
embodiments may be made from two or more materials of differing
flexibility, such as silicone and a polyurethane. An exemplary
polyurethane for this purpose is Tecothane.RTM., which is
commercially available from Hermedics Polymer Products, Wilmington,
Mass. Use of the term "overmold" herein is not intend to limit the
invention to embodiments in which overmold 48 is a molded
structure. Overmold 48 may be a molded structure, or may be a
structure formed by any process.
[0072] Overmold 48 can be shaped to contour to cranium 12, e.g.,
may be concave along at least one axis, and may be contoured at its
edges to prevent skin erosion on the scalp of patient 14. The
flexibility and shape of overmold 48 may improve the comfort and
cosmetic appearance of modular IMD 10 under the scalp. Further
details regarding the overmold, the concavity of the flexible
overmold, and techniques for restricting intermodular motion in a
modular IMD 10 may be found in a commonly-assigned U.S. patent
application entitled "OVERMOLD FOR A MODULAR IMPLANTABLE MEDICAL
DEVICE," assigned Attorney Docket No.: 1023-332US01/P-11798.00, and
a commonly-assigned U.S. patent application entitled "REDUCING
RELATIVE INTERMODULE MOTION IN A MODULAR IMPLANTABLE MEDICAL
DEVICE," assigned Attorney Docket No.: 1023-333US01/P-11797.00.
[0073] In the illustrated embodiment, modular IMD 10 also includes
lead connector modules 50A and 50B (collectively "lead connector
modules 50") formed within overmold 48 to receive leads 16 or lead
extensions coupled to leads 16. Conductors 52 extend from lead
connector modules 50 to hermetic feedthroughs (not illustrated)
within housing 36 of control module 30. Lead connector modules 50
may be formed anywhere within overmold 48. In embodiments where
overmold 48 includes a rigid material in addition to a flexible
material, the rigid material may form at least part of lead
connector modules 50 to secure leads 16 or lead extensions, and to
protect conductors 52 from damage that may result from flexing
within overmold 48.
[0074] FIG. 5 is a block diagram illustrating control module 30 of
modular IMD 10. As described above, control module 30 includes
control electronics that control the functioning of modular IMD 10
within housing 36. The control electronics include a processor 60,
which may take the form of a microprocessor, digital signal
processor (DSP), application specific integrated circuit (ASIC),
field-programmable gate array (FPGA), or other logic circuitry.
[0075] Control module 30 also includes a memory 62, such as a
read-only memory (ROM), random access memory (RAM),
electronically-erasable programmable ROM (EEPROM), flash memory, or
the like. Memory 62 may store program instructions that may be
executed by processor 60 and thereby control the functioning of
modular IMD 10. Processor 60 may also store data colleted during
treatment and/or monitoring of patient 14 within memory 62.
[0076] In some embodiments, control module 30 includes telemetry
circuitry 64, which enables processor 60 to communicate with other
devices such as an external programming device via radio-frequency
communication. Telemetry circuitry 64 may include a telemetry coil
(not illustrated), which may be fabricated of windings of copper or
another highly conductive material. The configuration and location
of telemetry coil within housing 36 may be dictated by the
available space within housing 36 and the communication
requirements of telemetry circuitry 64. Further detail regarding
the configuration and location of the telemetry coil may be found
in a commonly-assigned U.S. patent application entitled
"LOW-PROFILE IMPLANTABLE MEDICAL DEVICE," assigned Attorney Docket
No: 1023-335US01/P-11801.00.
[0077] In some embodiments modular IMD 10 delivers electrical
stimulation, and more particularly, control module 30 includes
therapy delivery circuitry 66 within housing 36 that generates
electrical stimulation. In exemplary embodiments, therapy delivery
circuitry 66 comprises circuits for the generation of electrical
stimulation in the form of pulses, such as capacitors and switches.
In embodiments in which modular IMD 10 is a neurostimulator coupled
to leads 16 that include a plurality of electrodes, therapy
delivery circuitry 66 may deliver the pulses to a switch matrix 68,
which comprises an array of switches. In such embodiments,
processor 60 interacts with switch matrix 68 to select electrodes
for delivery of generated stimulation pulses. Based on the
selections made by processor 60, switch matrix 68 delivers the
pulses to conductors that pass through feedthroughs in housing 36
and to electrical contacts on leads 16 that are electrically
coupled to the desired electrodes carried by leads 16.
[0078] The illustrated components of control module 30 receive
energy from the power source within power source module 32 via
interconnect member 44 (FIG. 3). In some embodiments in which the
power source is rechargeable, control module 30 receives energy
inductively captured by recharge module 34 via interconnect member
46, and includes power management circuitry 70 that controls the
recharging and discharging of the power source. Power management
circuitry 70 may ensure that the power source is not overcharged,
over-discharged, or harmed. In some embodiments, power management
circuitry 70 includes circuits to measure voltages, currents or
temperatures associated with the power source, or rates of change
of these parameters, and controls recharging and discharging
according to the measured values. Power management circuitry 70 may
also include circuits, such as rectifier circuits, for converting
charge-balanced voltages, e.g., AC voltages, provided by recharge
coil 42 (FIG. 4) into DC voltages for recharging the power
source.
[0079] FIGS. 6A and 6B are top-view diagrams illustrating other
example modular IMDs 80 and 90, respectively. More particularly,
FIGS. 6A and 6B illustrate modular IMDs 80 and 90 that include
alternative arrangements of modules 30, 32 and 34, flexible
interconnect members 44 and 46, and lead connection modules 50.
Further, FIGS. 6A and 6B illustrate alternatively shaped overmolds
82 and 92, respectively, that at least partially encapsulate
modules 30, 32 and 34 of IMDs 80 and 90.
[0080] FIGS. 3 and 6A illustrate substantially triangular
configurations of modules 30, 32 and 34 within modular IMDs 10 and
80, respectively. Further, overmolds 48 and 82 of IMDs 10 and 80
have substantially triangular shapes. Substantially triangular
configurations of modules 30, 32 and 34 and substantially
triangularly shaped overmolds such as overmolds 48 and 82 may be
preferred for some implantations, such as that described with
reference to FIG. 2, in order to reduce the depth of the pocket
formed under the scalp of patient 14. Reduced pocket depth may
allow for easier explant of modular IMDs 10 and 80 in the event
explant is required. However, other configurations are possible,
such as the substantially linear configuration of modules 30, 32
and 34 within modular IMD 90 illustrated FIG. 6B.
[0081] Although illustrated in FIGS. 3, 6A and 6B as connecting
recharge module 34 to control module 30, in some embodiments
flexible interconnect member 44 directly connects recharge module
34 to power source module 32. Consequently, in such embodiments
power source module 32 includes circuitry to control the recharging
and discharging of the power source instead of, or in addition to
power management circuit 70 within control module 30.
[0082] FIG. 7 is a block diagram illustrating power source module
32 of modular IMD 90. Power source module 32 includes a
rechargeable power source 100 within housing 38, which may include
a battery and/or a capacitor. In the illustrated embodiment in
which power source module 32 directly receives energy inductively
captured by recharge module 34 via flexible interconnect member 44,
power source module 32 also include power management circuit 102
that controls the recharging and discharging of power source 100.
As described above with reference to power management circuitry 70
illustrated in FIG. 5, power management circuitry 102 may ensure
that power source 100 is not overcharged, over-discharged, or
harmed. In some embodiments, power management circuitry 102
includes circuits to measure voltages, currents or temperatures
associated with power source 100, or rates of change of these
parameters, and controls recharging and discharging of power source
100 according to the measured values.
[0083] Power management circuitry 102 may also include circuits,
such as rectifier circuits, for converting charge-balanced
voltages, e.g., AC voltages, provided by recharge coil 42 (FIG. 4)
into DC voltages for recharging power source 100. In some
embodiments in which interconnect member 44 is non-hermetic, power
management circuit 102 includes modulating circuits, i.e., circuits
that enable power management circuit 102 to deliver energy to
control module 30 in the form of charge-balanced voltages on a
conductor. In such embodiments, control module 30 includes
circuits, such as rectifier circuits, to convert the
charge-balanced voltages to DC voltages for use by components of
control module 30.
[0084] FIGS. 8A and 8B are cross-sectional diagrams illustrating
two example configurations of overmold 92 of modular IMD 90, the
cross-section taken along axis 94 (FIG. 6B). FIG. 8A illustrates an
embodiment of IMD 90 in which overmold 92 fully encapsulates
modules 30, 32 and 34, while FIG. 8B illustrates an embodiment of
IMD 90 in which overmold 92 partially encapsulates modules 30, 32
and 34. In embodiments where overmold 92 partially encapsulates
modules 30, 32 and 34, overmold 92 leaves portions 110, 112 and 114
of modules 30, 32 and 34 exposed, respectively. Portions 110, 112
and 114 may, as illustrated in FIG. 8B, be lower portions of
modules 30, 32 and 34, e.g., portions of the modules that are
proximate to cranium 12 when modular IMD 90 is implanted
thereon.
[0085] Embodiments in which overmold 92 fully encapsulates modules
30, 32 and 34 may be preferred as providing greater patient comfort
and protection of the modules. However, in some embodiments in
which portions 110, 112 and 114 are exposed, troughs may be drilled
into the surface of cranium 12 that are sized to receive the
portions. By recessing portions 110, 112 and 114 into such troughs,
the height of modular IMD 90 above cranium 12 may be reduced.
[0086] FIGS. 9A and 9B are top-view diagrams illustrating another
example modular IMD 120. In the illustrated embodiment, recharge
module 34 is not encapsulated by overmold 122, but is instead
tethered to overmold 122 by a flexible tether member 124. Flexible
tether member 124 is made of a flexible material, such as silicone,
to allow substantial movement of recharge module 34 relative to
other modules 30 and 32 as illustrated in FIG. 9B. In some
embodiments, flexible tether member 124 is shaped as a helix to
allow recharge module freedom of movement some significant distance
away from other modules 30 and 32. Recharge module 34 can be moved
to improve inductive coupling for energy transfer and/or the
cosmetics of modular IMD 120 when implanted on cranium 12.
[0087] FIGS. 10, 11A, 11B and 12 are conceptual diagrams
illustrating other example modular IMDs 130, 140 and 150. Modular
IMD 130 of FIG. 10 does not include recharge module 34. Rather,
recharge coil 42 is embedded within overmold 132, and surrounds
control module 30 and power source module 32.
[0088] In some embodiments, such as modular IMD 140 illustrated in
FIGS. 11A and 11B, control module 30 and power source module 32 are
not separately housed. Rather, as illustrated in FIG. 11A, modular
IMD 140 includes a single housing 142 to house both control module
30 and power source module 32. Housing 142 may be hermetic and
formed of titanium, stainless steel, or a ceramic. Recharge module
34 may, as shown in FIG. 11A, be tethered to housing 142 by
flexible tether member 124 so that recharge module 34 can be moved
freely relative to housing 142. Further, modular IMD 140 may, as
shown in FIG. 11A, include a ceramic connector block 144 to receive
leads 16.
[0089] FIG. 11B illustrates a side-profile of modular IMD 140.
Housing 142 may be a low-profile housing with a thickness 146 that
is approximately less than or equal to 6 millimeters. Techniques
for arranging components of an IMD to enable a low-profile housing
may be found in the commonly-assigned U.S. patent application
entitled "LOW-PROFILE IMPLANTABLE MEDICAL DEVICE," assigned
Attorney Docket No: 1023-335US01/P-11801.00. A low-profile housing
142 may allow modular IMD 140 to be implanted, for example, within
an upper buttocks region of patient 14.
[0090] FIG. 12 is a conceptual diagram illustrating a modular IMD
150 in which housing 36 of control module 30 and housing 38 of
power source module 32 have substantially cylindrical shapes. The
substantially cylindrical shapes of control module 30 and power
source module 32 may enable IMD 150 to be implanted within the
periphery, e.g., the limbs, of patient 14.
[0091] As illustrated in FIG. 13, a circuit board 160 within
control module 30 may include flex tape regions 162 that enable the
circuit board 160 to have a "stacked" configuration. The stacked
configuration of circuit board 160 can enable circuit board 160 to
fit within cylindrical housing 36 illustrated in FIG. 12. In some
embodiments, circuit board 160 may be constructed entirely of flex
tape, and may be have a "rolled" configuration that can enable
circuit board 160 to fit within cylindrical housing 36 illustrated
in FIG. 12. A variety of primary and rechargeable batteries that
have substantially cylindrical shapes are commercially available,
and can be used as a cylindrically-shaped power source module
32.
[0092] FIGS. 14A and 14B are top-view diagrams illustrating other
example modular IMDs 170 and 180. Modular IMDs 170 and 180 include
at least one module in addition to control module 30, power source
module 32, and recharge module 34. In particular, instead of or in
addition to delivering electrical stimulation, modular IMDs 170 and
180 deliver one or more therapeutic agents to patient 14.
[0093] Modular IMDs 170 and 180 may be coupled to one or more
catheters for delivery of the therapeutic agent to patient 14.
Modular IMD 170 includes a reservoir module 172 that contains the
therapeutic agent within a housing. The housing may contain a
bladder that holds the therapeutic agent, and may provide access to
the bladder for refilling. The housing may be formed of, for
example, titanium, stainless steel, a ceramic, a polymer, or
silicone.
[0094] In such embodiments, control module 30 includes a pump (not
shown), and processor 60 (FIG. 5) controls delivery of the
therapeutic agent by the pump. The pump within control module 30
receives the therapeutic agent from reservoir module 172 via a
flexible interconnect member 174 that includes to enable transfer
of the therapeutic agent. Flexible interconnect member 174 need not
be hermetic, and may be made from, for example, titanium, stainless
steel, a ceramic, a polymer, or silicone. An overmold 176 may at
least partially encapsulate the housing of reservoir module 172 in
addition to the housings of control module 30, power source module
32, and recharge module 34.
[0095] Modular IMD 180 illustrated in FIG. 14B includes a
separately housed pump module 182 that includes a pump. The pump
within pump module 182 may be used to deliver the therapeutic agent
within reservoir module 172 instead of or in addition to a pump
within control module 30. In the illustrated embodiment, pump
module 182 rather than control module 30 is coupled to reservoir
module 172 by flexible interconnect member 174, and the pump within
pump module 182 receives the therapeutic agent within reservoir
module 172 via a lumen within flexible interconnect member 174.
[0096] The housing of pump module 182 may be made from, for
example, titanium, stainless steel, or a ceramic. A flexible
interconnect member 184 carries one or more conductors used by
processor 60 (FIG. 5) to control the delivery of the therapeutic
agent to patient 14 by the pump within pump module 182. The
flexible interconnect member 184 may need to be hermetic, and may
be made from, for example, titanium, stainless steel, or a ceramic.
A flexible overmold 186 may at least partially encapsulate the
housings of reservoir module 172 and pump module 182, in addition
to the housings of control module 30, power source module 32, and
recharge module 34.
[0097] Various embodiments of the invention have been described.
These and other embodiments are within the scope of the following
claims.
* * * * *