U.S. patent application number 10/730878 was filed with the patent office on 2004-09-09 for lead connection module of a modular implantable medical device.
Invention is credited to Janzig, Darren A., Singhal, Ruchika, Skime, Robert M., Wahlstrand, Carl D..
Application Number | 20040176816 10/730878 |
Document ID | / |
Family ID | 32512690 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040176816 |
Kind Code |
A1 |
Singhal, Ruchika ; et
al. |
September 9, 2004 |
Lead connection module of a modular implantable medical device
Abstract
A modular implantable medical device includes two or more
interconnected modules and an overmold that at least partially
encapsulates each of the housings of the modules. The overmold also
includes a lead connection module for accepting an external lead.
The lead connection module electrically and mechanically couples
the lead to the components of the implantable medical device.
Inventors: |
Singhal, Ruchika;
(Minneapolis, MN) ; Wahlstrand, Carl D.; (Lino
Lakes, MN) ; Janzig, Darren A.; (Centerville, 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.: |
10/730878 |
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 1/3758 20130101;
A61N 1/37518 20170801; A61N 1/3754 20130101; A61N 1/3605 20130101;
A61N 1/37514 20170801 |
Class at
Publication: |
607/045 |
International
Class: |
A61N 001/02 |
Claims
What is claimed is:
1. An implantable medical device comprising: at least two
interconnected modules, each of the modules comprising a housing;
and an overmold that at least partially encapsulates each of the
housings, the overmold comprising a lead connection module for
accepting an external lead.
2. The implantable medical device of claim 1, wherein at least one
module comprises a control module containing electronic
components.
3. The implantable medical device of claim 1, wherein the overmold
comprises a first material and a second material, and the lead
connection module is deployed within the first material.
4. The implantable medical device of claim 3, wherein the first
material comprises a non-elastomeric material.
5. The implantable medical device of claim 1, the lead connection
module comprising at least one feed-through wire to electrically
couple an external lead to an electronic component within the
implantable medical device.
6. The implantable medical device of claim 1, wherein the lead
connection module includes a mechanical lead securing
mechanism.
7. The implantable medical device of claim 6, wherein the
mechanical lead securing mechanism comprises a tool-less mechanical
lead securing mechanism.
8. The implantable medical device of claim 1, wherein the
implantable medical device has a maximum thickness of between
approximately 4 millimeters and approximately 8 millimeters.
9. An overmold for a modular implantable medical device comprising:
a first material configured to hold at least part of a module; a
second material coupled to the first material; and a lead
connection module configured to accept an external lead, the lead
connection module being deployed within the overmold.
10. The overmold of claim 9, wherein the first material comprises a
non-elastomeric material.
11. The overmold of claim 9, wherein the second material comprises
an elastomeric material.
12. The overmold of claim 9, wherein the second material comprises
silicone.
13. The overmold of claim 9, wherein the lead connection module is
deployed within the first material.
14. The overmold of claim 9, wherein the lead connection module is
configured to receive an iso-diametric external lead.
Description
[0001] This application claims the benefit of:
[0002] 1. U.S. Provisional Application entitled "CRANIAL
NEUROSTIMULATOR AND METHOD," Ser. 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," Ser. 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," Ser. 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," Ser. No. 60/503,946,
(Attorney Docket No. P-11697.00), filed on Sep. 20, 2003; and
[0006] 5. U.S. Provisional Application entitled "Thin Neuro
Stimulation System, Device and Method," Ser. No. 60/507,857,
(Attorney Docket No. P-20211.00), filed on Oct. 1, 2003. The entire
content of each of these U.S. Provisional Applications is
incorporated herein by reference.
[0007] 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:
[0008] 1. U.S. Patent Application entitled "MODULAR IMPLANTABLE
MEDICAL DEVICE," to Carl D. Wahlstrand et al., filed Dec. 9, 2003,
assigned Attorney Docket No.: 1023-318US01/P-10891.00;
[0009] 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;
[0010] 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;
[0011] 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;
[0012] 5. U.S. Patent Application entitled "REDUCING RELATIVE
INTER-MODULE MOTION IN A DISTRIBUTED MODULAR IMPLANTABLE MEDICAL
DEVICE," to Carl D. Wahlstrand et al., filed Dec. 9, 2003, assigned
Attorney Docket No.: 1023-333US01/P-11797.00;
[0013] 6. 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
[0014] 7. 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.
[0015] 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
[0016] The invention relates to medical devices, and more
particularly, to implantable medical devices that deliver therapy
to and/or monitor a patient.
BACKGROUND
[0017] 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.
[0018] 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
hybrid circuit that includes 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.
[0019] Due to these limitations, an IMD is typically implanted
within the abdomen, upper pectoral region, or interclavicular
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.
[0020] 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
interclavicular 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. 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
[0021] In general, the invention relates to a lead connection
module of a modular implantable medical device. In order to provide
an implantable medical device with a smaller profile so that the
IMD can better fit into available body locations, various
functional components of the IMD are separated into individual
interconnected modules. This modular architecture for the
implantable medical device permits the device footprint to be
distributed over a larger area while making the profile smaller. In
addition, the multiple modules and their respective flexible
interconnections may permit the overall shape of the implantable
medical device to be formed to better match the body location into
which it is to be implanted.
[0022] In a typical application, the component modules within the
IMD are coupled to one or more leads that are deployed within a
patient's body. External leads are used to electrically connect the
external locations to a control module within the implantable
medical device, and the control module can monitor the electrical
activity, or regulate administration of therapy, or both.
Accordingly, it is desirable for the external leads be both
electronically and mechanically coupled to the implantable medical
device. The present invention provides such a coupling of the
external leads to the implantable medical device.
[0023] In one embodiment, the invention is directed to a an
implantable medical device that includes at least two
interconnected modules, each of the modules comprising a housing,
and an overmold that at least partially encapsulates each of the
housings. The overmold comprises a lead connection module that is
configured to accept an external lead. In some variations, the
invention supports an overmold made of multiple materials, such as
elastomeric and non-elastomeric materials.
[0024] In another embodiment, the invention is directed to an
overmold for a modular implantable medical device. The overmold
comprises a first material configured to hold at least part of a
module, a second material coupled to the first material, and a lead
connection module configured to accept an external lead, the lead
connection module being deployed within the overmold.
[0025] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0026] FIGS. 1A and IB are diagrams illustrating use of an
implantable medical device in a patient according to an example
embodiment of the present invention.
[0027] FIG. 2 is a schematic diagram illustrating an implantable
medical device according to an embodiment of the present
invention.
[0028] FIG. 3A and 3B are schematic diagrams illustrating an
implantable medical device according to another embodiment of the
present invention.
[0029] FIGS. 4A-4F are schematic diagrams illustrating various
orientations of multiple modules within an implantable medical
device according to various embodiments of the present
invention.
[0030] FIG. 5A is a schematic diagram illustrating the construction
of an overmold and modules used in construction of an implantable
medical device according to the present invention.
[0031] FIG. 5B is an exploded view of an embodiment of the overmold
and modules shown in FIG. 5A.
[0032] FIG. 5C is a side view of an embodiment of the overmold and
modules shown in FIG. 5A.
[0033] FIGS. 6A-6B are schematic diagrams illustrating an example
embodiment of a multi-module implantable medical device having
multiple interconnect sites according to the present invention.
[0034] FIGS. 7A-7B are schematic diagrams illustrating an example
embodiment of a multi-module implantable medical device having
tethered interconnect sites according to the present invention.
[0035] FIG. 7C is a perspective view of a multi-module implantable
medical device such as that depicted in FIGS. 7A and 7B.
[0036] FIGS. 8A-8B are schematic diagrams illustrating the
interaction of components of an implantable medical device that are
part of an overmold according to the present invention.
[0037] FIGS. 9A-9B are schematic diagrams illustrating an
electronic module of a multi-module implantable medical device
having a connection leads according to the present invention.
DETAILED DESCRIPTION
[0038] FIGS. 1A and 1B are diagrams illustrating use of an
implantable medical device (IMD) in a patient according to an
example embodiment of the present invention. An IMD 101 is
implanted within a patient 100 in order to permit IMD 101 to
provide therapies to the patient 100. In the example illustrated
within FIGS. 1A-1B, IMD11 is implanted under the scalp of the
patient 100 in order to locate the device 101 as close as possible
to the location of leads 102 that provide the therapy.
[0039] FIG. 1A shows patient 100 with IMD 101 deployed beneath his
scalp. In FIG. 1A, IMD 101 is a neurostimulator that provides deep
brain stimulation via leads 102 deployed in the brain of patient
100. IMD 101 is deployed in proximity to site of stimulation
therapy. IMD 101 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 and Parkinson's
disease and neurodegenerative disorders.
[0040] Although IMD 101 is depicted as a neurostimulator, the
invention is not limited to applications in which the IMD is a
neurostimulator. The invention may be employed with IMDs that
perform any monitoring or therapeutic functions. The invention is
not limited to IMDs that include leads deployed in the brain, but
may also be employed with leads 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. Nor is the invention limited to IMDs that are coupled to
electrodes. The invention may be employed with IMDs coupled to any
sensing or therapeutic elements, such as temperature sensors or
motion sensors. The invention may also be employed with different
types of IMDs including, but not limited to, IMDs operating in an
open loop mode (also referred to as non-responsive operation), IMDs
operating in a closed loop mode (also referred to as responsive),
and IMDs for providing monitoring and/or warning.
[0041] In general, IMD 101 has a low profile, i.e., IMD 101 is thin
to permit the IMD 101 to be deployed effectively, comfortably and
cosmetically and under the scalp. In one embodiment of the
invention, IMD 101 has a maximum thickness of between approximately
4 millimeters and approximately 8 millimeters. The use of a reduced
profile may reduce the risk of infection, skin erosion and cosmetic
issued related to the implantation of IMD 101.
[0042] Many locations within a patient do not present adequate
profile for implantable medical devices. As such, many uses of such
devices employ lengthy leads located remote from an implantation
site of the IMD. The use of these lengthy leads requires
complicated insertion procedures from the site of the IMD to the
site of lead deployment that may cause medical complications to the
patient as well as may lead to failures in connection leads. By
constructing IMD 101 as a set of distributed modules connected
together as described herein, IMD 101 may be deployed proximate to
a treatment or monitoring site.
[0043] While the embodiment of IMD 101 shown in FIGS. 1A-1B is
implanted under the scalp of patient 100 and may be used when the
therapy provided to patient 100 includes neural stimulation of a
brain, other embodiments of IMD 100 permit the device to be
implanted at many other locations within the body. In addition, IMD
101 includes a plurality of interconnected modules. Each module
generally perform assigned functions.
[0044] In the typical embodiment depicted in FIG. 1B, IMD 101
includes three modules, namely, a control module 103, a power
supply module 104 and a recharge module 105. Control module 103
typically includes the electronic components associated with the
functions of IMD 101. In a typical implementation, control module
103 may include a hybrid circuit that includes digital circuits
such as integrated circuit chips and one or more microprocessors,
and analog circuit components. Accordingly, control module 103 may
also be referred to as an electronic module. Power supply module
104 typically comprises one or more energy storage devices, such as
a rechargeable lithium ion battery. Recharge module 105 typically
includes one or more coils for transmitting or receiving
electromagnetic energy through the scalp. The transmitted energy
may include energy to be stored in power supply module 104. In some
embodiments, the transmitted energy may also include communication,
such as information encoded in radio frequency transmissions.
[0045] Individual modules 103 and 104 may be encased in
biocompatible metal shields such as titanium shield halves, and may
be sealed against contamination. In addition, individual modules
103 and 104 may include insulation to electrically isolate the
electrical components inside the modules from the metal shields.
The modules are coupled to an overmold 106 which may be made of a
biocompatible material. Use of the term "overmold" herein is not
intend to limit the invention to embodiments in which the overmold
is a molded structure. Overmold may be a molded structure, or may
be a structure formed by any process.
[0046] In some embodiments of the invention, overmold 106 encases
all modules 103, 104 and 105. In other embodiments, overmold 106 is
disposed over or around the modules without encasing the modules.
In further embodiments, overmold 106 acts as a "frame" to hold the
modules in a fixed position relative to one another, but does not
fully cover the modules. Some features of the overmold, and
variations on the shape of the overmold, are presented below. In
general, the shape of the overmold depends upon the arrangement of
the modules. The overmold may be made of a variety of materials,
such as flexible silicone. The overmold may also include a rigid
polymer such as Ticothane surrounded by flexible silicone. The
invention is not limited to these materials, however, and the
overmold may comprise any combination of elastomeric and/or
non-elastomeric materials.
[0047] FIG. 2 is a schematic diagram illustrating an IMD according
to another embodiment of the present invention. In this example
embodiment, the IMD 201 is arranged in a triangular configuration,
and includes three modules: a control module 210, a power supply
module 211, and a recharge module 212. Overmold 214 at least
partially covers the housings of control module 210 and power
source supply module 211, and also at least partially covers
recharge module 212. These three modules are physically connected
together to construct IMD 201, and any modules may also be
electrically coupled to one another.
[0048] IMD 201 also includes two lead connection modules 213A, 213B
for accepting an external lead. In particular, overmold 214
includes lead connection modules 213A, 213B, and lead connection
modules 213A, 213B need not be fixedly coupled to any module 210,
211 or 212. Lead connection modules 213A, 213B contain a set of
lead connection modules that permits external leads to be connected
to the IMD 210. In the case of electronic leads, for example, lead
connection modules 213A, 213B include one or more conductors that
electrically couple the external leads to control module 210. The
triangular configuration of IMD 201 permits IMD 201 to possess a
thin profile by spreading the modules over a larger surface area.
The triangular shape also helps to keep the surface area compact.
The structure of IMD 201 may also be curved to conform to the shape
of the location within a patient in which the device is being
implanted. For example, implantation of IMD 201 under the scalp of
a patient may be accomplished if the overall shape of IMD 201 is
curved to follow the shape of a patient's skull. Any number of
shapes may be used to match a particular IMD 201 to an implantation
location for a device.
[0049] FIG. 3A and 3B are schematic diagrams illustrating an IMD
according to yet another embodiment of the present invention. In
this embodiment of IMD 301, a flat device is shown that consists of
multiple modules. This embodiment of IMD 310 may be used in other
locations within a patient in which the implantation location does
not require such an exact match between the device and physical
structures of the patient such as bone or muscle. IMD3 01 may
provide a small profile when implanted as to not protrude
excessively once implanted.
[0050] The flat embodiment shown in FIGS. 3A-3B may represent a
device that may be a pectoral implant that may be used to treat
angina, to provide vagal nerve stimulation, or to provide cardiac
rhythm management. Similar devices may be implanted into an upper
buttock implant location, into an abdomen location, and into
periphery. A device implanted into an upper buttock location may be
useful in urological and gastrological implantation therapies. A
device implanted into an abdomen location may be useful in
providing pain, spasticity, and chemotherapy treatment. A device
implanted into a periphery location may be useful in providing
muscle stimulation, on-site nerve stimulation, and diaphragm
stimulation therapies.
[0051] IMD 301 comprises an overmold 302 that includes two lead
connection modules 303A, 303B for accepting an external lead. In
FIGS. 3A and 3B, lead connection modules 303A, 303B are depicted
open to illustrate inclusion in overmold 302.
[0052] Additional alternate embodiments for implantable medical
devices implemented according to principles of the present
invention may also include non-electrical based therapies such as
targeted introduction of fluids and similar therapeutic materials
using pumps and reservoirs of material. One skilled in the art will
recognize that any number of implantable devices may be possible
without deviating from the spirit and scope of the present
invention as recited within the attached claims.
[0053] FIGS. 4A-4F are schematic diagrams illustrating exemplary
configurations and orientations of modules within IMD 401A through
401F (hereinafter 410), according to various embodiments of the
present invention. IMD 401 consists of multiple modules that may be
arranged into any number of orientations as shown in the various
embodiments of FIGS. 4A-4F. For reference, each IMD 401 is depicted
deployed proximate to the skull of a patient, with leads 402A and
402B deployed through burr holes 402A and 402B and coupled to IMD
401. The leads are coupled to the IMD via lead connection modules
415A and 415B. As shown in FIGS. 4A-4F, the lead connection modules
may assume a variety of orientations relative to other components
of IMD 401.
[0054] In each of these embodiments, IMD 401 has three modules as
discussed above in reference to FIGS. 1B and 2: a control module
410, a power source module 411, and a recharge module 412. An
overmold 413 at least partially covers the housings of control
module 410 and power source module 411. The modules may be arranged
into a number of orientations as long as any interconnections
between the modules may be routed within the device. The various
embodiments include triangular configurations, as is shown in FIGS.
4A-4C, or linear configurations as shown in FIGS. 4D-4F. In FIG.
4D, one of the three modules, such as the recharge module, is
deployed as a tethered module 414 rather than being covered by
overmold 413.
[0055] The invention is not limited to the deployments of the lead
connection modules shown in FIGS. 4A-4F. The lead connection
modules may be located on various positions within IMD 401. Lead
connection modules may be oriented, for example, to permit the
leads to be routed to lead locations in an efficient manner or to
support management of excess lead length. Any number of other
orientations and alternate embodiments may be constructed according
to principles of the present invention and consistent with the
claims recited herein.
[0056] FIGS. 5A-5C are schematic diagrams illustrating an exemplary
construction of an overmold used in construction of an IMD
according to the present invention. FIG. 5A illustrates that IMD
501 comprises a set of modules 510-512, a set of motion restriction
elements, such as motion restriction fibers 521. In FIG. 5A, motion
restriction fibers 521 are coupled to modules 510 and 511, and are
covered at least in part by overmold 522. Overmold 522 typically
includes a solid biocompatible material. Overmold 522 may comprise
an elastomeric material that is soft and flexible, such as
silicone. In addition or in the alternative, overmold 522 may
comprise a non-elastomeric material that imparts rigidity to IMD
501. In one embodiment, for example, a non-elastomeric material in
overmold 522 acts as a "frame" to hold the modules in a fixed
position relative to one another, and does not fully cover the
modules. Overmold 522 covers, at least in part, the components and
modules within IMD 501 while providing a flexible structure that
permits the device 501 to conform to fit each individual patient.
Because overmnold 522 is typically flexible, IMD 501 may benefit
from motion restriction devices such as motion restriction fibers
521, which provide structural integrity to device 501 once
implanted into the patient.
[0057] Additional details regarding the set of motion restriction
devices 521 are described in co-pending and commonly assigned U.S.
Patent Application entitled "REDUCING RELATIVE INTER-MODULE MOTION
IN A DISTRIBUTED MODULAR IMPLANTABLE MEDICAL DEVICE," assigned
Attorney Docket No.: 1023-333US01/P-11797.00.
[0058] FIG. 5B illustrates that the overmold 522 may include a
non-elastomeric, or "hard" component 531 in addition to an
elastomeric, or "soft" component 532. In FIG. 5B, the
non-elastomeric component 531 is shaped to conform to the shape of
at least one of modules 510-512 such that the modules may be
restrained from motion by the non-elastomeric components. The
non-elastomeric components 531 are typically made of a solid
biocompatible material such as polysulfone, and may also be made of
metal such as titanium.
[0059] The non-elastomeric components 531 are utilized in locations
in which motion is to be restricted. Any or all modules may be
constrained by one or more hard components 531. Overmold 522,
including elastomeric and non-elastomeric components, can be
fabricated into a single structure before the modules 510-512 are
inserted into the device 501.
[0060] Generally, overmold 522 serves a number of functions. For
example, overmold 522 incorporates motion restriction elements
within the device 501, and attaches to modules and other elements
to provide a unified device. In addition, overmold 522 provides a
smooth interface surface for the device as it interacts with the
patient, and protects electrical connections and feed through wires
that connect modules to external leads.
[0061] Overmold 522 may also include a durometric specific material
to provide desired device qualities such as flexibility and
structural integrity. In addition, the material used to construct
overmold 522 may possess a thermal conductivity characteristic to
either act as a heat sink, or act as an insulator to shield the
patient 100 from any excess heat from IMD 501. Because IMD 501 may
be constructed from a large number of modules to perform a desired
task, the materials selected for used in constructing the overmold
522 may vary as needed by each embodiment.
[0062] FIG. 5C illustrates that overmold 522 provides sloped
interface 541 between an exemplary module 542 within IMD 501 and
the patient's body. In embodiments in which IMD 501 is implanted
within tight spaces, such as under the scalp of the patient, sloped
interface 541 provides a smooth transition and eases sharp edges
that are known to cause possible points of stress for tissue. An
angle of interface from the patient's body and the sloped interface
541 can be approximately 135 degrees.
[0063] Additional details regarding the overmold 522 are described
in co-pending and commonly assigned U.S. Patent Application
entitled "OVERMOLD FOR A MODULAR IMPLANTABLE MEDICAL DEVICE,"
assigned Attorney Docket No.: 1023-332US01/P-11798.00.
[0064] FIGS. 6A-6B are schematic diagrams illustrating an example
embodiment of a multi-module IMD 601 having multiple interconnect
sites according to the present invention. FIG. 6A shows a
distributed IMD have multiple lead connection modules 613 that are
located adjacent to each other while being near a control module
610. In contrast, FIG. 6B shows a distributed IMD have multiple
lead connection modules 613 that are located on opposite sides of
the control module 610. In FIGS. 6A and 6B, lead connection modules
are included in overmold 622. The lead connection modules 613
provide a mechanism for electrically connecting electronics within
control module 610 to one or more external leads 643. The external
leads provide an electrical signal path from a desired part of the
patient's body to IMD 601.
[0065] The embodiment shown is FIG. 6A is used when it is desirable
for the external leads 643 to follow similar signal path lengths
from the control module 610 to the treatment or monitoring site of
the body. The embodiment of FIG. 6B may be used in cases in which
the external leads 643 are farther apart. Because the lead
connection modules 613 provide electrical connections between the
control module 610 and the external leads 643, the lead connection
modules 613 are typically located close to the control module 610
to reduce a length for electrical interconnections between them.
Additional details regarding the interconnection of the control
module 610, the lead connection modules 613, and the external leads
643 is discussed below in reference to FIGS. 8A-8B.
[0066] FIGS. 7A-7B are schematic diagrams illustrating an example
embodiment of a multi-module IMD having tethered interconnect sites
according to the present invention. In a first embodiment shown in
FIG. 7A, an overmold 722 of an IMD 701 may cover and connect a
plurality of modules 710-712 while not covering lead connection
modules 713, which are part of a tethered interconnection housing
761. As shown in FIG. 7B, tethered interconnection housing 761 is
optional.
[0067] In these embodiments, the lead connection modules 713 that
are used to connect external leads (not shown) to the device 701
are not contained within the overmold 722. As such, the
implantation of the device would not require the insertion of
external leads into the 722. In addition, the external leads may be
located a distance away from the overall device 701. Such an
arrangement may assist in the management of the external leads as
they are placed within the patient and routed to a lead
location.
[0068] In an alternate embodiment shown in FIG. 7C, overmold 722
may include mechanical structures such one or more grooves or a
pouch to contain and route the external leads and aid lead
management. An exemplary structure, a groove 750, is depicted in a
perspective view of IMD 701. In some implantations, external leads
may possess an excess length that may be managed to reduce the
risks of lead migration and lead damage.
[0069] FIGS. 8A-8B are schematic diagrams illustrating an exemplary
interaction of components of an IMD 801. FIG. 8A provides a side
view of an overmold 822, which includes one or more soft or
elastomeric components 832 and one or more hard or non-elastomeric
components 831, which interface with a control module 810.
Non-elastomeric component 831 may be shaped to mate with the module
810 to provide motion restriction for the module. Non-elastomeric
component 831 may be mechanically connected to other modules using
a motion restriction device (not shown). The overmold 822 covers
all of these components in this embodiment. A through hole 851 may
be located through the non-elastomeric component 831 and
elastomeric component 832 to provide an attachment point for IMD
801. In some embodiments, IMD 801 may be anchored in place using
bone screws or other anchoring devices. Through holes 851 permit
IMD 801 to be mechanically anchored to the patient once the device
801 is positioned at a desired location. In the embodiment shown in
FIG. 8A, a bone screw inserted into through hole 851 would seat
against non-elastomeric component 831, but the invention
encompasses embodiments in which a bone screw would seat against
another component, such as control module 810.
[0070] FIG. 8B illustrates a top view of the device 801 having
elastomeric component 832 of overmold 822 covering the
non-elastomeric components 831 that frame control module 810. The
through hole 851 used as an attachment point is shown as part of
non-elastomeric component 831 that is covered by elastomeric
component 832. The shape of non-elastomeric component 831 and
control module 810 are shown as being rectangular in this
embodiment. However, one skilled in the art will recognize that any
shape for the non-elastomeric component 831 and control module 810
may be used without deviating from the spirit and scope of the
present invention.
[0071] In both FIG. 8A and 8B, a lead interconnect device 813 is
included within the non-elastomeric components 831 of overmold 822.
In these examples, the non-elastomeric component 831 restrains
control module 810 and external leads 843. Typically, the external
leads have iso-diametric proximal ends for connection of the
external leads 843 to IMD 801. An external lead 843 is inserted
into the lead connection module in order to connect the external
leads 843 to electronics within control module 810 of IMD 801. This
electrical connection from the control module 810 to the external
leads 843 is made using a module connection lead wire 846 that
extends from control module 810 and physically connects with the
external lead 843 within the lead connection module 813.
[0072] The lead connection module 813 may also include a mechanical
lead securing mechanism 845 that engages the external lead 843 to
restrain its motion and ensure electrical connection with
feed-through wires 846. In the embodiment of FIG. 8A, a tool 847 is
used to engage the mechanical lead securing mechanism 845 within
the lead connection module 813. In this embodiment, the mechanical
lead securing mechanism 845 comprises a mechanical set-screw that
is tightened by a screwdriver. An example of such a mechanical lead
securing mechanism 845 is a low-profile DBS lead extensions
manufactured by Medtronic Inc. In alternate embodiments, the
mechanical lead securing mechanism 845 may be tool-less using a
variety of known securing technologies that ensures the external
lead 843 does not separate from the lead connection module 813.
Tool-assisted or tool-less coupling of leads to the IMD both allow
medical personnel to couple leads to the IMD quickly and
securely.
[0073] FIGS. 9A-9B are schematic diagrams illustrating a control
module of a multi-module IMD having a connection leads according to
the present invention. FIG. 9A provides a prospective view of a
control module 910 to illustrate a set of feed-through wires 946
that electrically couple electronics 950 within the control module
810 to external leads as discussed above in reference to FIGS. 8A
and 8B. Similarly, FIG. 9B provides a side view of the control
module 910 of FIG. 9A to again illustrate the use of the
feed-through wires 946 as discussed above.
[0074] While the above embodiments of the present invention
describe a lead interconnect module of a modular implantable
medical device, one skilled in the art will recognize that the use
of a module structure are merely exemplary embodiments of the
present invention. It is to be understood that other embodiments
may be utilized and operational changes may be made without
departing from the scope of the present invention as recited in the
attached claims.
[0075] As such, the foregoing description of the exemplary
embodiments of the invention has been presented for the purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed. Many modifications and variations are possible in light
of the above teaching. It is intended that the scope of the
invention be limited not with this detailed description, but rather
by the claims appended hereto. The present invention is presently
embodied as a lead interconnect module of a modular implantable
medical device.
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