U.S. patent application number 17/578289 was filed with the patent office on 2022-05-05 for bone implants for the treatment of infection.
The applicant listed for this patent is Silver Bullet Therapeutics, Inc.. Invention is credited to Paul E. CHIRICO, Bohdan Wolodymyr CHOPKO, Houdin DEHNAD.
Application Number | 20220133376 17/578289 |
Document ID | / |
Family ID | 1000006094049 |
Filed Date | 2022-05-05 |
United States Patent
Application |
20220133376 |
Kind Code |
A1 |
DEHNAD; Houdin ; et
al. |
May 5, 2022 |
BONE IMPLANTS FOR THE TREATMENT OF INFECTION
Abstract
Described herein are devices, systems and methods for treating
disease and/or infection by the release of silver from an implant
over an extended period of time. In particular, the devices
described herein may be used to treat infections such as
osteomyelitis by the controlled release of silver ions from
multiple sites of an extended-use implant. This implant typically
includes a plurality of arms that both anchor and help distribute
the released ions within the tissue. Power may be applied to
release the silver ions into the tissue.
Inventors: |
DEHNAD; Houdin; (El Granada,
CA) ; CHOPKO; Bohdan Wolodymyr; (Henderson, NV)
; CHIRICO; Paul E.; (Campbell, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Silver Bullet Therapeutics, Inc. |
San Jose |
CA |
US |
|
|
Family ID: |
1000006094049 |
Appl. No.: |
17/578289 |
Filed: |
January 18, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16532350 |
Aug 5, 2019 |
11224471 |
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17578289 |
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16015085 |
Jun 21, 2018 |
10368929 |
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16532350 |
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15012803 |
Feb 1, 2016 |
10004548 |
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16015085 |
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13527389 |
Jun 19, 2012 |
9248254 |
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15012803 |
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12870082 |
Aug 27, 2010 |
8221396 |
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13527389 |
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61359549 |
Jun 29, 2010 |
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61340587 |
Mar 19, 2010 |
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61237506 |
Aug 27, 2009 |
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Current U.S.
Class: |
606/331 |
Current CPC
Class: |
A61L 2300/404 20130101;
A61M 25/0084 20130101; A61L 31/088 20130101; A61L 2300/104
20130101; A61L 2300/602 20130101; A61B 17/866 20130101; A61B
2017/00893 20130101; A61L 31/022 20130101; A61L 2300/102 20130101;
A61F 2002/30677 20130101; A61L 2400/16 20130101; A61B 2017/561
20130101; A61F 2310/00113 20130101; A61B 17/56 20130101; A61L 31/16
20130101 |
International
Class: |
A61B 17/86 20060101
A61B017/86; A61B 17/56 20060101 A61B017/56; A61M 25/00 20060101
A61M025/00; A61L 31/02 20060101 A61L031/02; A61L 31/08 20060101
A61L031/08; A61L 31/16 20060101 A61L031/16 |
Claims
1. A method of treating or preventing infection in a bone, the
method comprising: inserting a silver-releasing implant into a bone
in a collapsed configuration; expanding the implant into the bone
from the collapsed configuration into an expanded configuration
having multiple pathways through the bone; releasing silver ions
from one or more silver reservoirs on the implant into the bone
over an extended period of time at a sustained level; and removing
the implant after a predetermined period of time that is longer
than a week.
2. The method of claim 1, wherein inserting comprises pre-forming
passageways for the implant.
3. The method of claim 1, wherein inserting comprises inserting a
passage forming implant having a plurality of expandable members to
pre-form the multiple pathways.
4. The method of claim 1, wherein expanding the implant comprises
driving a plurality of arms of the implant through the bone by
extending the arms from the implant, wherein the arms are
sufficiently stiff and/or sharp to penetrate bone.
5. The method of claim 4, wherein inserting comprises inserting the
implant with a delivery device configured to hold one region of the
implant while longitudinally moving another region of the implant
to extend the arms.
6. The method of claim 4, wherein removing comprises removing the
implant with a delivery device configured to secure a proximal
region of the implant while longitudinally moving another region of
the implant to contract the arms.
7. The method of claim 1, further comprising anchoring the implant
in the bone.
8. The method of claim 1, wherein releasing silver ions comprises
applying energy to drive the release of ions.
9. The method of claim 1, wherein releasing silver ions comprises
applying less than 50 microAmps of power to release ions.
10. The method of claim 1, wherein releasing silver ions comprises
applying pulsatile energy to release ions.
11. The method of claim 1, wherein releasing silver ions comprises
applying energy in pulses to maintain a silver ion concentration
above a minimum inhibitory concentration.
12. The method of claim 1, wherein releasing silver ions comprises
releasing silver ions to maintain a silver ion concentration above
a minimum inhibitor concentration in a region of the bone
surrounding the implant for a period of at least one week.
13. The method of claim 1, wherein releasing silver ions comprises
releasing silver ions to maintain a silver ion concentration above
a minimum inhibitor concentration in a region of the bone
surrounding the implant for a period of at least one month.
14. The method of claim 1, wherein releasing silver ions comprises
releasing silver ions to maintain a silver ion concentration above
a minimum inhibitor concentration in a region of the bone
surrounding the implant for a period of between about one day and
six months.
15. The method of claim 1, further comprising sampling a patient
tissue when removing the implant.
16. The method of claim 1, further comprising sampling a patient
tissue using a sampling member on the implant when removing the
implant.
17. The method of claim 1, wherein the method is a method of
treating osteomyelitis.
18. A method of treating or preventing infection in a bone, the
method comprising: inserting a silver-releasing implant into a bone
in a collapsed configuration; expanding a plurality of arms from
the implant into the bone from the collapsed configuration into an
expanded configuration wherein the expanded arms extend in a
pattern having multiple pathways through the bone; galvanically
releasing silver ions from one or more silver reservoirs on the
arms into the bone over an extended period of time at a sustained
level; and removing the implant after a predetermined period of
time that is longer than a week.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 16/532,350, filed Aug. 5, 2019, titled "BONE
IMPLANTS FOR THE TREATMENT OF INFECTION," now U.S. Pat. No.
11,224,471, which is a continuation of U.S. patent application Ser.
No. 16/015,085, filed Jun. 21, 2018, titled "BONE IMPLANTS FOR THE
TREATMENT OF INFECTION," now U.S Pat. No. 10,368,929, which is a
continuation of U.S. patent application Ser. No. 15/012,803, titled
"BONE IMPLANTS FOR THE TREATMENT OF INFECTION," filed Feb. 1, 2016,
now U.S. Pat. No. 10,004,548, which is a continuation of U.S.
patent application Ser. No. 13/527,389, titled "BONE IMPLANTS FOR
THE TREATMENT OF INFECTION," filed Jun. 19, 2012, now U.S. Pat. No.
9,248,254, which is a continuation of U.S. patent application Ser.
No. 12/870,082, titled "BONE IMPLANTS FOR THE TREATMENT OF
INFECTION," filed Aug. 27, 2010, now U.S. Pat. No. 8,221,396, which
claims priority to the following U.S. provisional patent
applications: Provisional Patent Application No. 61/237,506, titled
"SILVER ELLUTING BONE IMPLANTS AND METHODS OF USE," filed on Aug.
27, 2009; Provisional Patent Application No. 61/340,587, titled
"ANTIMICROBIAL ION ELUTING IMPLANTABLE DEVICE," filed on Mar. 19,
2010; and Provisional Patent Application No. 61/359,549, titled
"SILVER ELUTING BONE IMPLANTS AND METHODS OF USE," filed on Jun.
29, 2010. Each of these applications is herein incorporated by
reference in its entirety.
INCORPORATION BY REFERENCE
[0002] All publications and patent applications mentioned in this
specification are herein incorporated by reference in their
entirety to the same extent as if each individual publication or
patent application was specifically and individually indicated to
be incorporated by reference.
FIELD
[0003] The devices, systems and methods described herein relate
generally to the treatment of infection, and particularly to the
treatment of bone infections such as osetomyelitis using a bone
implant that releases silver ions.
BACKGROUND
[0004] Bone infections, such as osteomyelitis, can be debilitating
or even fatal, and are notoriously difficult to treat. For example,
osteomyelitis is an acute or chronic bone infection that may be
caused by bacteria or fungi. The infection that causes
osteomyelitis may start in another part of the body and spread to
the bone through the blood. The infection may also spread to a bone
from infected skin, muscles, or tendons next to the bone, as in
osteomyelitis that occurs under a chronic skin ulcer (sore). Bone
infection can also start after bone surgery, especially if the
surgery is done after an injury or if metal rods or plates are
placed in the bone. In children, the long bones are usually
affected. In adults, the feet, spine bones (vertebrae), and the
hips (pelvis) are most commonly affected.
[0005] Treatment of osteomyelitis is typically intended to prevent
the infection from getting worse and ultimately to eliminate it
from the body. The currently accepted treatment for osteomyelitis
requires an extended period of intravenous antibiotics. Antibiotics
are given to destroy the bacteria causing the infection. More than
one antibiotic may be given at a time. The antibiotics are usually
given intravenously, and must be taken for at least 4-6 weeks,
sometimes longer. In some cases, surgery may be required in order
to remove dead bone tissue, and open space left by the removed bone
tissue may be filled with bone graft or packing material that
promotes the growth of new bone tissue. If an orthopedic prosthesis
is present near the site of infection, treatment may also require
surgical removal of the prosthesis and infected tissue surrounding
the area. A new prosthesis may be implanted in the same operation
or delayed until the infection has gone away.
[0006] Chronic osteomyelitis may require amputation, especially in
patients with diabetes or poor blood circulation. Furthermore,
osteomyelitis may be particularly serious when it develops in
patients having an implant or prosthesis. When bone becomes
infected, pus produced within the bone may result in an abscess
that limits the bone's blood supply. The lost blood supply can
result in chronic osteomyelitis. This chronic infection can cause
symptoms, including pain and disability, which persist for
years.
[0007] Implants, and particularly silver-coated implants, have been
suggested for use to control the spread of bacteria and the
development of infection; however, such coatings have not proven
effective. Silver coatings have been typically too limited to treat
infected regions that are not immediately adjacent to the silver.
In addition, the silver in most coatings elutes far too slowly to
repel or inhibit colonizing bacteria. Although more quickly-eluting
silver coatings have been described, such coatings typically do not
last more than a few hours or days, and are not sufficient for the
longer-term treatment usually required to treat osteomyelitis and
similar infections. In particular, previously described devices are
not capable of delivering a sustained level of silver ions to a
large region of bone for a sufficient time period.
[0008] U.S. Pat. No. 6,500,165 to Frank describes one variation of
an active antisepsis device that is intended to actively release
silver from an implanted body site. However, this implant is
limited by the delivery surface, and is not readily anchorable into
a tissue that is already necrotic or damaged by infection,
including infected bone tissue. US 2006/00004431 to Fuller et al.
describes a similar device, having similar limitations.
[0009] Described below are implants that may address these problems
and may be used to treat infections such as osteomyelitis. These
devices may be implanted over an extended period even in bone or
other tissue structures that are damaged or weakened by infection,
and release silver ions and/or other antimicrobial or therapeutic
substances.
SUMMARY OF THE DISCLOSURE
[0010] Described herein are anti-microbial silver-releasing
implants that may be used to treat bone infections including
osteomyelitis, as well as methods of treating bone infections such
as osteomyelitis using these implants.
[0011] In general, the devices described herein are implants
configured for insertion into a bone for an extended period of time
(e.g., days, weeks, months, years, etc.). The bone implant may be
anchored within the bone, and typically includes a plurality (e.g.,
2 or more, 3 or more, 4 or more, etc.) of arms that are extendable
into the bone in a deployed or anchored (or deployed and anchored)
configuration. Thus, in general, these implant may have a deployed
configuration, in which the arms extend from the implant into the
bone along different pathways through the bone, and a delivery
configuration, in which the arms are retracted. In the retracted
configuration, the implant may be linear or compact, simplifying
the insertion into the bone. In some variations, the arms are
individually extendable. In some variations the arms are connected
to each other and can be extended all together or in subsets.
[0012] The arms may be rigid, and may be configured for penetrating
the bone, particularly the cancellous bone. For example, the arms
may have a sharp or beveled edge. The arms may be formed of a
material and/or shape to have sufficient column strength for
extending or pushing the arm into the cancellous bone. In other
variations, the arms are placed into pre-formed passages, and
therefore have only nominal stiffness or rigidity (or column
strength). The arms may be elongate members having a tubular or
flattened shape. In some variations the arms have a round, oval,
rectangular, or other cross-section. In some variations the arms
are formed of a metal (including alloys), plastic, ceramic or the
like. In particular, the arms may be formed of a shape memory alloy
such as a nickel titanium alloy (e.g., Nitinol).
[0013] In general, each of the arms in the plurality of arms
includes a source of silver. The source of silver may be referred
to as a silver reservoir, and may be a solid silver material. The
reservoir of silver may be a silver plating or coating on all or a
portion of each arm. In some variations, the silver reservoir is a
core of silver material within an arm. At least one surface of the
reservoir of a particular arm may be exposed along all or portion
of the arm. In some variations, different arms include different
silver reservoirs and different exposed openings into the
reservoirs.
[0014] As used herein an arm may include a wire (e.g., filament), a
tube, a spike, a coil, etc. An arm is generally elongate and
configured for extension from the implant when inserted into the
bone (e.g., conversion into the deployed configuration). An arm may
be hollow or solid, and may include one or more
non-silver-releasing regions as well as silver-releasing regions.
In some variations, the arm includes structures that help anchor
the arm (or the entire implant) within the bone. For example, the
arm may include hooks, notches, prongs, or the like. In some
variations the arms include a deflection region that is deflected
to extend the arm from the implant when converting the implant into
the deployed configuration. The deflection region may be bent,
curved, angled, or expanded from the typically more linear
configuration of the arm in the delivery configuration. In some
variations, the arm is pre-formed into a shape (including the
deployed shape), and extending the arm from the implant during
deployment into the bone allows the arm(s) to extend to their
pre-formed shape. In some variations the arm includes a deflection
ramp, notch or other structure to allow another arm to deflect
during deployment, by moving against the adjacent arm. Examples of
this are described in greater detail below.
[0015] The silver reservoir of each arm is typically connected to a
silver-release driver that provide motivation to release silver
ions from the implant into the bone. The silver-release driver may
be a voltage and/or current source, which may in turn be connected
to control logic that regulates the power applied (and therefore
the silver release). In some variations the silver-release driver
is a galvanic reactor metal (e.g., a metal that, when placed in
contact with the silver reservoir, drives the galvanic release of
silver from the implant).
[0016] For example, one variation of an implant as described
herein, the implant includes a guide body or structure (including a
telescoping body) from which two or more silver-releasing arms (in
this example, filaments) may be controllably extended. The implant
body and/or the filaments are configured to be inserted into bone
in a collapsed configuration in which the arms (filaments) are
withdrawn into the guide body. Once inserted within the bone, the
filaments may be extended into the bone. The implant may eventually
(e.g., after days, weeks, months, etc.) be withdrawn from the bone
by withdrawing the filaments back into the guide body (or removing
them completely). In some variations, the implant guide body is
left in position, and a new "core" region of arms/filaments may be
inserted in the same position, using the anchored guide. Thus, the
implant may be "recharged" to continue to release silver ions. In
this example, one or more power sources may be connected to the
silver-releasing electrodes on the filaments and/or the body, so
that the silver may be actively released. Also described herein are
methods of using these devices and methods and devices for
inserting and/or removing them.
[0017] As mentioned, some of the implants described herein include
a current-controlled or voltage-controlled power source, including
control circuitry, connectable to one or more silver-releasing arms
(e.g., wires, tubes, spikes, coils, etc.). The devices maybe
configured to branched delivery of ions (e.g., by including a
plurality of ion-delivery elements that branch out to cover an area
of tissue and/or bone). In some variations, the device may be
galvanic or may include galvanic release of ions in addition to
active release. The current used for active release may be in the
microamp range (e.g., between about 1 microamp and about 50
microamps, between about 1 to about 30 microamps, between about 1.5
to 15 microamps, etc.).
[0018] For example, described herein are implants for insertion in
to bone to treat infection, the implant having a collapsed
insertion configuration and an expanded deployed configuration. The
implant may include: a plurality of arms configured to extend from
the implant in the deployed configuration, wherein each of the arms
comprises a reservoir of silver configured to be released from the
implant into the bone; an elongate and rigid guide comprising a
plurality of deflection pathways, wherein the plurality of arms are
movably coupled to the elongate guide so that they may be extended
from the deflection pathways and deployed to different bone regions
to convert the implant from the collapsed insertion configuration
into the expanded deployed configuration; and a silver-release
driver coupled to the reservoirs of silver to drive release of
silver ions from each of the plurality of arms.
[0019] In some variations, the implant further includes a bone
anchor configured to secure the implant at least partially within a
bone. The bone anchor may be coupled to (or integral with) the
elongate guide body. For example, the anchor may include one or
more fastening or attachment sites for sutures, screws or the like.
An anchor may include a projecting element (e.g., prong, etc.) that
secured into the bone.
[0020] The elongate guide may be an elongate hollow member within
which the arms are contained so that they can be extended for
deployment. In some variations, the guide is a solid member to
which the arms are secured. For example, the guide may include a
core member around which the arms are slideably arranged. The guide
may include channels, ramps, deflection regions, or the like for
guiding each or the arms during deployment (or retrieval). During
deployment the distal ends of the arms typically move from the
central axis of the implant into an expanded configuration out of
the implant.
[0021] The deflection pathways of the elongate guide may include
openings, e.g., windows, along the long axis of the elongate hollow
member. Arms may exit these windows to expand into the bone during
deployment.
[0022] For example, an elongate guide may include an elongate inner
member having a longitudinal axis and a deflection ramp region
forming the plurality of deflection pathways that are configured to
deflect the arms from longitudinal axis as they are extended into
the deployed configuration.
[0023] As mentioned above, the plurality of arms may be formed of
any appropriate material, including a shape-memory material. For
example, in some variations, the arms may comprise a nickel
titanium alloy (e.g., Nitinol) covered by a non-reactive (e.g.,
passivation) layer beneath a silver coating, wherein the
non-reactive layer is formed directly onto the nickel titanium
material, after removal (or before formation) of a titanium oxide
layer from the outer surface of the nickel titanium alloy. The
non-reactive layer may be an adhesion layer that enhances the
adhesion of silver to the shape-memory material. Typically nickel
titanium will form an oxide layer on the outer surface. However,
this oxide layer may prevent the material from easily bonding to
the silver coating or silver reservoir. Thus a non-reactive layer
(e.g., gold, etc.) may be used to both help adhere the silver to
the nickel titanium, and to prevent leeching of nickel from the
alloy.
[0024] The arms may be bent and/or curved when extended in the
deployed configuration. As mentioned, the arms may comprise
tissue-penetrating ends. In general, the arms are configured to
expand within cancellous bone during insertion of the implant. In
some variations, the plurality of arms are distributed
asymmetrically about the radius of the elongate guide in the
insertion configuration.
[0025] The plurality of arms may include arms of different lengths,
and shapes. The silver reservoirs may be differently positioned and
configured on each arm or groups of arms. Typically, the implants
described herein may have the arms arranged so that, when the arms
are in the expanded configuration, they form a space-filling
structure from which silver may be released to cover a
predetermined bone region. Thus, the arms may be expanded into
different directions and orientations. The arms may be arranged
symmetrically or asymmetrically when expanded into the deployed
configuration.
[0026] The plurality of arms may be configured to release silver
along their entire expanded length, or from a plurality of discrete
locations along their length. As mentioned, the reservoir of silver
may be a silver coating, and/or a silver core.
[0027] Also described herein are delivery devices for use with the
implants described herein. A delivery device may be adapted to
allow insertion and expansion of the implant while in the bone. In
some variations the delivery devices may also be configured to
allow removal/retrieval of the implant. The delivery device may be
used to remove the entire implant or just a portion of the implant,
such as the arms, for example, when reloading or recharging the
implant with new silver-releasing arms. In some variations the
delivery device may be used to remove and replace the
silver-release driver or a component of the driver (e.g.
battery).
[0028] For example, in some variations the implant includes a
delivery device coupling region at a proximal end of the elongate
guide, wherein the coupling region is configured to couple the
implant to a delivery device so that the plurality of arms may be
expanded or retracted relative to the elongate guide. The coupling
region may be a threaded region, for example. Any appropriate
coupling regions may be used. The implant may include a first
delivery device coupling region at a proximal end of the elongate
guide and a second delivery device coupling region coupled to a
proximal end of the plurality of arms, wherein the first delivery
device coupling region and the second delivery device coupling
region are each configured to couple the implant to a delivery
device so that the plurality of arms may be expanded or retracted
relative to the elongate guide.
[0029] As mentioned, above, the silver-release driver may comprise
a battery. In some variations the silver-release driver comprises
logic configured to provide pulsatile stimulation to drive release
of the silver ions.
[0030] Also described herein are implants for insertion into a bone
to treat infection, the implant having an expanded deployed
configuration configured for long-term release of silver ions and a
collapsed insertion configuration. The implant may comprise: an
elongate outer housing having a plurality of channel windows along
the length of the elongate body; an inner treatment member
comprising a plurality of radially-expandable arms configured to
extend from the channel windows of the elongate outer body; wherein
each of the radially-expandable arms comprises a silver reservoir,
and wherein the inner treatment member is axially slideable
relative to the outer housing to expand the plurality of
radially-expandable arms from the collapsed to the deployed
configuration; and a silver-release driver coupled to the
reservoirs of silver to drive release of silver ions from each of
the plurality of arms.
[0031] As mentioned, in some variations the plurality of
radially-expandable arms are coated with silver. The plurality of
radially-expandable arms may be formed of a material having
sufficient stiffness to allow the arms to penetrate the target bone
region when extended from the channel windows.
[0032] The inner treatment member (or a portion of it) may be
formed of a nickel titanium alloy. In some variations, the distal
tips of the arms comprise chisel-shaped tissue-penetrating distal
tips.
[0033] The implant may also include a first applicator coupling
region on a proximal end of the outer housing and a second
applicator coupling region on the proximal end of the inner
treatment member, wherein the coupling regions are configured to
couple the implant to a delivery device so that the plurality of
arms of the inner treatment member may be expanded or retracted
relative to the outer housing.
[0034] Also described herein are implants for insertion into a bone
to treat infection, the implant having an expanded deployed
configuration configured for long-term release of silver ions. The
implant may include: a plurality of deflection arms having a first
axially elongated delivery configuration and a second radially
deflected delivery configuration, wherein each of the deflection
arms comprises a silver reservoir, and wherein the deflection arms
are further configured to slide axially relative to the other
deflection arms to convert the deflection arm from the delivery
configuration into the delivery configuration; further wherein the
plurality o deflection arms are adjacent to each other; a
deflection ramp on each deflection arm configured to convert an
adjacent deflection arm from the delivery configuration to the
deployed configuration as the adjacent deflection arm is moved
axially against the deflection ramp; and a silver-release driver
coupled to the reservoirs of silver to drive release of silver ions
from each of the plurality of deflection arms.
[0035] Also described herein are systems for treating osteomyelitis
by inserting an implant configured for the long-term release of
silver ions over a region of bone. A system may include a
silver-releasing implant (including any of the implants described
herein) and a delivery device. For example, the system may include
a silver-releasing implant including: a silver-releasing implant
having a collapsed insertion configuration and an expanded deployed
configuration, the implant comprising: a plurality of arms
configured to extend from the implant, wherein each of the arms
comprises a reservoir of silver configured to be released from the
implant into the bone; an elongate guide forming a plurality of
deflection pathways for the arms, wherein the plurality of arms are
movably coupled to the elongate guide so that the arms may be
extended from the elongate guide at different locations and
orientations when the implant is converted to the deployed
configuration; a first coupling member on a proximal end of the
elongate guide configured for releasably coupling to a delivery
device; and a silver-release driver coupled to the reservoirs of
silver to drive release of silver ions from each of the arms.
[0036] A delivery device may include an elongate insertion member
having a distal coupling region configured to releasably couple
with the first coupling member; and an arm-extender member
configured to couple with and extend the arms of the implant; and a
handle at a proximal end of the delivery device.
[0037] In some variations, the system includes a control on the
distal end configured to control extension/retraction of the arms
of the implant. The arm-extender of the delivery device may include
a coupling region at the distal end configured to releasably couple
with a coupler on the plurality of arms. The arm-extender may be a
push rod. In some variations, the arm-extender is slideably
disposed within the elongate insertion member for extending or
retracting the arms. The arm-extender may be configured to
separately engage one or a subset of the plurality of arms and to
separately control extension or retraction of the one or a subset
of arms.
[0038] Also describe herein are methods of treating infection in a
bone, the method comprising: inserting a silver-releasing implant
into a bone in a collapsed configuration; expanding a plurality of
arms from the implant into the bone from the collapsed
configuration into an expanded configuration wherein the expanded
arms extend in a pattern having multiple pathways through the bone;
releasing silver ions from one or more silver reservoirs on the
arms into the bone over an extended period of time at a sustained
level; and removing the implant after a predetermined period of
time that is longer than a week.
[0039] The step of inserting may comprise forming passageways
(passages) for the implant and the expanded arms (e.g., before
insertion of the implant). A device for forming the passageways may
be used. This device may be referred to as an implant template or
as a passage forming implant or device. The implant template may
have an expanded configuration shape that is similar to that of the
implant. For example, the implant template device may have a
plurality of projecting "arms" that are configured to be inserted
into the bone and form passages for the insertion of the implant.
In some variations the implant template and/or the arms of the
implant template are configured to cut, compress, carve, ablated,
or otherwise form channels in the bone into which the implant and
the implant arms of the implant can be inserted. For example, the
template device may include arms that are rigid, hard, sharp,
stiff, or otherwise tissue-penetrating. The arms of the template
device may be extendable or expandable. In some variations, the
template device is anchored to the bone so that one or more
components can be driven into or through the bone to form the arm
passageways. A central passageway may be formed first by drilling
or other means, and a passageway forming device can then be
inserted into the central passageway to form the passages for the
arms of the treatment implant. For example, the step of inserting
may comprise inserting a passage forming implant having a plurality
of expandable members to pre-form the passageways. Thereafter an
implant having a plurality of silver-releasing arms may be inserted
into the pre-formed passageways. The pre-formed passageways may be
large enough to accommodate the treatment implant, or they may act
as "pilot" holes or guides through the bone, so that the implant
arms themselves still penetrate the tissue, ensuring a tight
apposition between the implant and the bone. In some variations the
treatment implant has arms that are of relatively low column
strength, and benefit from the use of pre-formed passageways.
[0040] In some variations, the method includes the step of driving
the arms of the implant through the bone by extending the arms from
the implant, wherein the arms are sufficiently stiff and/or sharp
to penetrate bone.
[0041] The method may also include the step of anchoring the
implant in the bone. The implant may be anchored before
extension/expansion of the arms, or it may be anchored after
extension of the arms. Extending the arms into the delivery
configuration may help to anchor the implant in position. In some
variations the implant includes a guide or reference region, such
as a core region or an elongate outer housing, against which the
implant arms move to expand into the deployed configuration; this
guide or reference region may be anchored, and may include anchors
coupled thereto, as mentioned above.
[0042] The step of releasing silver ions may comprise applying
energy to drive the release of ions. For example, the method may
include applying less than 50 microAmps of power to release ions.
The step of releasing silver ions may comprise applying pulsatile
energy to release ions. The step of releasing silver ions may
comprise applying pulses of energy to maintain the silver ion
concentration above a minimum inhibitory concentration.
[0043] In general, the step of releasing silver ions may include
releasing silver ions to maintain the silver ion concentration
above a minimum inhibitor concentration in a predetermined region
of bone surrounding the implant for a predetermined period of time.
The minimum inhibitor concentration is typically the concentration
of silver ions necessary to treat infection by killing
microorganisms and inhibiting microbial growth. For example, the
minimum inhibitory concentration may be between about 0.01
microgram/ml and about 10 microgram/ml (e.g., between 0.1
microgram/ml and about 1 microgram/ml). Any appropriate
predetermined time period may be selected, including, for example,
about 1 week, 1 month, 2 months, 3 months, 6 months, 1 year, 2
years, etc. (including any time period between 1 week and five
years). The implant may be configured to provide the minimum
concentration for the predetermined time period based on the power
requirements and the silver-release driver (e.g., battery). The
region of the bone surrounding the implant is typically a region
extending from about a few mm to many cm around the arms of the
implant. The arms of the implant may be configured so that the
effective range of silver ion elevation to the minimum effective
concentration from the various arms overlaps, are adjacent, or are
additive in the overlapping regions between adjacent arms. Thus,
the implants described herein having multiple arms may provide an
enlarged region of elevated silver (compared to implants that do
not have multiple arms) even at lower power requirements.
[0044] As mentioned, the arms of the implant may be extended by
extending them from a guide region and/or by moving the arms
relatively to each other (e.g., over or against each other). A
delivery device may be used to facilitate the expansion of the arms
into the bone. In some variations, the step of inserting comprises
inserting the implant with a delivery device configured to hold one
region of the implant while longitudinally moving another region of
the implant to extend the arms.
[0045] After insertion, the silver-releasing (treatment) implant
may be removed using an inserter. For example, the implant may be
removed with a delivery device configured to secure a proximal
region of the implant while longitudinally moving another region of
the implant to contract the arms. All or just a portion of the
implant may be removed. For example, the arms of the implant may be
removed so as to insert a fresh silver reservoir for release. The
new implant arms may be inserted into the spaces in the one left by
the previous arms, or into new bone regions. In some variations,
the silver-release drive may be replaced in this manner, leaving
the rest of the implant in position. Alternatively, the arms may be
left in position and the rest of the implant (e.g., any core or
guide region) may be removed or replaced. In some variations, the
entire implant may be removed or replaced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] FIG. 1A is one variation of an anti-microbial
silver-releasing implant, as described herein.
[0047] FIG. 1B is an exploded view of the implant of FIG. 1A.
[0048] FIG. 2A shows the battery, arm housing and arms of the
device of FIGS. 1A and 1B.
[0049] FIG. 2B shows the distal end region of the housing from
which the arms may extend.
[0050] FIG. 3 shows another variation of a set of arms.
[0051] FIG. 4A shows one variation of an arm.
[0052] FIG. 4B shows another variation of an arm.
[0053] FIGS. 5A and 5B illustrate one variation of an implant in
which the silver-releasing arms are retracted (FIG. 5A) and
extended (FIG. 5B).
[0054] FIG. 6 illustrates one variation of the implant described
herein in which the silver-releasing arms are releasing silver into
the surrounding tissue.
[0055] FIG. 7 illustrates a region of bone (tibia) exhibiting
osteomyelitis.
[0056] FIGS. 8A-8C illustrate insertion of an implant as described
herein into the bone using a telescoping inserter.
[0057] FIG. 9 shows another variation of an implant.
[0058] FIGS. 10A-10C illustrate the implant of FIG. 9; FIG. 10C
illustrates the implant inserted into a rabbit femur.
[0059] FIG. 11A illustrates the effect of an implant that uses
galvanic release of ions.
[0060] FIGS. 11B and 11C illustrate one variation of the galvanic
release of silver ions which may be used in an implant as described
herein.
[0061] FIGS. 12A-12D illustrate another variation of an implant for
releasing an antimicrobial ion.
[0062] FIGS. 13A-13E show another variation of a system including a
silver-releasing implant for insertion into a bone to treat
infection.
[0063] FIGS. 14A-14D illustrate another variation of a system
including a silver-releasing implant for insertion into a bone to
treat infection.
[0064] FIGS. 15A-15C show another variation of a system including a
silver-releasing implant for insertion into a bone to treat
infection.
[0065] FIGS. 16A-16C show another variation of a silver-releasing
implant for insertion into a bone to treat infection.
[0066] FIG. 17 shows one variation of an arm including a pair of
bone-sampling regions.
[0067] FIG. 18 shows one variation of an implant including
bone-sampling regions.
[0068] FIGS. 19A-19E illustrates one variation of a system
including a silver-releasing implant for insertion into a bone to
treat infection.
[0069] FIGS. 19F-19J illustrate insertion of the implant shown in
FIG. 19A.
[0070] FIGS. 19K and 19L illustrate various methods for removing
the implant of FIG. 19A.
[0071] FIGS. 20A and 20B illustrate another variation of a
silver-releasing implant for insertion into a bone to treat
infection.
[0072] FIGS. 21A and 21B illustrate another variation of a
silver-releasing implant for insertion into a bone to treat
infection.
[0073] FIG. 21C shows a cross-section through the implant of FIG.
21A.
[0074] FIG. 21D shows an alternative variation of the implant of
FIG. 21A.
[0075] FIGS. 22A and 22B illustrate another variation of a
silver-releasing implant for insertion into a bone to treat
infection and an insertion/activation device.
[0076] FIG. 23 illustrates one variation of an implant inserter and
remover.
[0077] FIGS. 24A-24E illustrate removal of one variation of a
silver-releasing implant, as described herein.
[0078] FIG. 25 shows one variation of a coupling region that may be
used as a connector.
[0079] FIGS. 26A and 26B illustrate another coupling structure and
method of coupling.
[0080] FIGS. 27A and 27B illustrates the coupling means shown in
FIGS. 26A and 26B expanding an inner member within a surrounding
outer member.
[0081] FIGS. 28A and 28B illustrate another coupling structure and
method of coupling.
[0082] FIGS. 29A-29D show one variation of a silver-releasing
arm.
[0083] FIGS. 30A and 30B illustrate another variation of a
silver-releasing implant as described herein.
[0084] FIGS. 31A and 31B show another variation of a
silver-releasing arm.
[0085] FIG. 31C illustrates another variation of silver-releasing
implants deployed in a bone region.
[0086] FIGS. 32A and 32B illustrate another variation of a
silver-releasing implant for implantation into a bone.
DETAILED DESCRIPTION
[0087] Described herein are devices, systems and methods for
treating bone infection by the active release of an antimicrobial
(e.g., silver ions) from an implant. In particular, the devices
described herein may be used to infections such as osteomyelitis by
the controlled release of silver ions from multiple sites of an
extended-use implant. The implant is typically configured to be
implanted into bone for an extended period of time (e.g., days,
weeks, months, or even longer) and to release silver ions (and in
some embodiments other medicaments). In these variations, active
release of silver ions may lead to greater tissue concentrations,
and thereby have an enhanced bactericidal or therapeutic effect
compared to passive (e.g., diffusion) of ions or medicaments.
[0088] In some variations of the devices described herein, the
implant includes an implantable body from which one or more (often
a plurality) of silver-releasing arms (e.g., filaments, plates,
wires, branches, etc.) may be extended into the tissue. In
particular, the implant may include a guide body having a plurality
of silver-releasing arms. The arms are typically extendable from
the guide body. The guide body may steer or direct the arms as they
are extended from the body, and/or may coordinate the expansion of
the arms. The guide body may be an outer member (e.g., a hollow
cannula member) out of which the arms extend, or it may be an inner
core member against which the arms slide, or some combination
thereof. The guide body may include a plurality of channels,
openings, deflection ramps, or other guide elements for engaging
and guiding the arms. The arms typically slide against (relative
to) the guide body. The guide body may be rigid. The guide body is
typically elongate (e.g., having a longer length than width) and
may have any appropriate cross-section, e.g., round, oval, flat,
square, etc.
[0089] The arms may be configured to penetrate the bone upon
leaving the guide body. For example, the arms maybe reinforced with
a durable metal substrate such as a shape memory alloy (e.g.,
nickel titanium). These arms may be coated, filled, embedded or may
otherwise carry a source of silver ions that is in communication
with one or more silver-release drivers. In some variations, the
silver reservoirs coupled to the silver-release driver by one or
more electrical contacts (e.g., an anode (+)); the implant guide
body may also includes one or more return contacts (e.g., cathodes
(-)) which may be located anywhere on the implant, spaced apart
from the cathode, so that silver ions may be released from the
implant into the bone or other surrounding tissue. For example, the
return contact(s) may be on a different portion of the filament, on
another filament, or on the body of the implant.
[0090] The body of the device may be configured to penetrate the
bone, and may have a tapered distal end and/or tip. In some
variations, the distal end of the implant includes bone-engaging
members (e.g., teeth, grips, threads, etc.) for securing the
implant into the bone; in other variations the distal end of the
implant is substantially smooth so that the implant is engaged
within the bone by the filaments.
[0091] As mentioned, the arms may be extendable and/or retractable
from the body of the implant. In some variations, one or more
ports, windows, or openings on the guide body region may permit
extension of the filaments from the device. The arms maybe extended
by advancing out of the body. Thus, the implant may include a
delivery configuration in which the one or more arms are retracted
within the guide body, and an implanted configuration in which the
one or more arms are extended from the body (e.g., out of a port or
ports on the body). In some configurations the arms are partially
retracted into the body in the delivery configuration, or be flush
with the surface of the body. In some variations the arms are
retractable back within the body of the implant (e.g., for removal
or repositioning of the device). In some variations the arms may be
extended gradually or incrementally. For example, as the implant is
operated and silver is released from one or more regions of the
arms, additional arms (or completely new arms) may be extended from
the guide body with additional sources of silver.
[0092] Any appropriate arm that may contain or support a source of
silver ions for active release may be used. For example, arms may
be solid or hollow. Further, the source of silver ions may be
applied to the outside of all or a portion of the arm (e.g., by a
coating), or it may be contained within the wall of the filament,
or within a core region of the arm. In some variations, the arm is
filled with the releasable silver. Hollow arms may be particularly
useful for co-delivery of other agents such as medicaments in
addition to the delivery of silver ions (e.g., antibiotics, bone
growth promoting agents, etc.). Thus, the arms may include a lumen
or passageway through which material may be released.
[0093] The arms may be configured to penetrate tissue, and in
particular, they may be configured to penetrate bone. For example,
the arms may be reinforced, or may include a relatively stiff
material such a metal having a sufficient strength and durability.
The distal end of the arm may be tissue penetrating (e.g., sharp).
The arm may be any appropriate size. For example an arm may have a
diameter of between about 0.05 mm and about 5 mm. The diameter of
the arm may be constant, or it may vary along the length of the
filament (e.g., it may taper distally). An implant may have arms of
different configurations (including lengths, shapes, materials,
silver reservoirs, etc.).
[0094] Arms may be pre-based to assume a shape when extended from
the body of the device. For example, when arms are formed of nickel
titanium or other shape-memory materials, the arm may be configured
to extend away from the body of the device. The exit port for the
arm from the body of the device may include a deflecting surface to
direct the arm in a desired location away from the body as it is
extended. In variations having more than one arm extendable from
the body, the arms may be extended independently or as a group or
plurality of groups.
[0095] Any of the devices described herein may also include one or
more sensors. For example, a pH sensor may be associated with the
body of the device for sensing pH in the surrounding of the bone.
pH may be one indicator of bacterial load, and the power or
frequency of silver release may be modified based on the pH
reading. Other sensor may include silver sensors (which may be used
to regulate the release). Internal sensors may also be provided.
For example, a sensor or detector may be included to monitor or
otherwise indicate the level of power in the implant, and/or the
level of silver. Information from these sensor(s) may be used by a
controller to modify the activity of the device (e.g.,
increasing/decreasing the release of silver), and/or it may be
communicated outside of the patient's body, via a wired or wireless
connection.
[0096] The active silver-release devices described herein may
include an on-board power source (e.g., a battery, inductive coil,
etc.) for applying current to release the silver. When a battery is
used, the silver source in placed in electrical contact with the
battery and the return electrode (e.g., cathode) is also placed in
electrical contact with the battery. As mentioned the silver source
(and anode) may be present on the arms and the return electrode
(cathode) may be present in one or more locations on the body,
arm(s) or elsewhere on the device, so that the silver can be
released in a desired pattern from the implant when in a subject's
body (e.g., within the bone). As mentioned, the device may also
include a control or controls (e.g., circuitry) for controlling the
applied power (e.g., current and/or voltage), for timing the active
powering of the device, and/or for controlling, communication or
monitoring with any sensors on the device, or any telemetry
associated with the device.
[0097] In operation, the device may be controlled so that silver is
released continuously or intermittently (in pulses), or based on
some pre-determined schedule (e.g., initially higher, or for a
longer period, which gradually tapers off). For example, if power
is applied by a current or voltage source, power may be applied
continuously or in pulses or bursts of pulses. Alternatively, the
device may be actively controlled, as mentioned above, so that
power is applied based on feedback from the tissue or implant. In
some variations, the device applies power to release silver
intermittently, for some on-period, followed by a quiescent period
(off-time). During the application of power (e.g., current), the
power applied may be continuous or variable. The power may be
pulsed (e.g., at some frequency) to help with release of the ions.
The current may be applied at any appropriate level. For example,
the applied current may be less than 10 mA (e.g., less than 1.0 mA,
less than 0.5 mA, etc.). The applied current may depend upon the
apparent load of the device (e.g., depending on where in the
body--or in the bone--the implant is positioned).
[0098] The power source for an implant may be voltage-regulated or
current regulated, which may also be referred to as voltage
controlled or current controlled. For example, the system may be
configured to maintain a target current or a target voltage. A
current controlled or voltage controlled system may be used to
achieve a constant current/voltage, or when the voltage or current
is controlled to be varying (e.g., ramped, pulsed, etc.). The
constant current may put out (cause the release of) the same amount
of silver, and may adjust the voltage to maintain the target (e.g.,
constant or relatively constant) current. The device may be limited
to prevent excessive voltages. The current controlled embodiments
may drive the ion-releasing reaction at a known or predetermined
rate. In voltage controlled embodiments, the device may keep the
concentration of the silver relatively constant, regardless of the
rate of release. This variation may allow the current to vary to
achieve a target (e.g., constant) voltage.
[0099] In general, the current range for a constant-current
configuration may be in the sub-microamp (e.g., nanoamp), microamp,
or milliamp range (e.g., approximately 1.5 .mu.A to 15 .mu.A).
Although the device may apply current in the milliamps range, this
may be unnecessary in order to provide sufficient concentration of
ions to have the desired effect. For example, a high-current
embodiment may result in an unnecessarily high concentration. In
some variations, the applied current is an extremely low current
(e.g., in the order of microamps or nanoamps). For example, the
current may be between about 1 microamp and 50 microamps. For
example, the current applied by the device (constant or varying)
may be approximately 1 microamp, 1.5 microamps, 2 microamps, 3
microamps, 4 microamps, 5 microamps, 10 microamps, 15 microamps, 20
microamps, 30 microamps, 40 microamps, 50 microamps, or any value
between these).
[0100] In some variations the implant is inserted using a
telescoping delivery device (e.g., cannula), or the body of the
implant is itself telescoping. Telescoping implants may be
configured to maximize or increase the tissue/therapeutic
interface. In addition, the telescoping implants allow for serial
dilation through necrosed or infected bone to healthy bone
providing a more stable implant anchor that is fully removable upon
therapy completion. Release of Ions:
[0101] As described herein the method of release of silver (or any
other ion, particularly antimicrobial ions) may be through an
electroporation-like release. A source of silver ions (e.g.,
silver, silver-ion doped materials, etc.) may be placed in
electrical communication with a first electrode (e.g., an anode
(+)). A single arm may have one or more such electrodes and/or
sources of silver ions. A return electrode (or plurality of return
electrodes (e.g., cathode (-)) may be placed some distance from the
first electrode(s), so that when power is applied across these
first electrode(s) and the return electrodes, ions are released to
travel into the body by the flow of current.
[0102] The arm structures described herein may be expanding
structures that both penetrate and anchor the implant into the
tissue, and also establish a broad distribution pattern for the ion
distribution. These arms (which may be a stiff, non-eroding
material such as Nitinol) may stabilize the implant even in
necrotic bone or other tissues and be fully retractable upon
completion of therapy.
[0103] Although many of the variations described herein are powered
by on-board power sources (e.g., battery, induction coil, etc.),
they may also be powered by an off-board power source, and may
include a cable or wire connection. For example, in some
variations, the devices may be placed or positioned by guidewire.
The guidewire may also be used to provide power to the device (thus
the guidewire may be otherwise insulated).
[0104] In any of the variations described herein the device may
include one or more on-board controllers, and may be controlled
automatically, programmed, or may receive input from one or more
sensors or communication sources (e.g., wireless communication)
that may control one or more aspects of the device (including the
time on/time off/frequency of current applied/level of current
applied/voltage applied/etc.). The power source may be internalized
(within the implant), and could use external control (e.g., an
external magnetic field) to activate/deactivate. In some
variations, communication or control may be via RF
communication.
[0105] Thus, in any of these variations, the device may be anchored
into the bone, at or near an infection site, or prophylactically
near a site that is prone for infection (e.g., near another implant
or orthopedic device). The implant may be configured to expand upon
insertion so that the arms are separated from the return
electrode(s) in a pattern sufficient to apply silver ions to the
infection region at the desired effective level.
[0106] In some variations the creation and release of the ions
(e.g., silver ions) may be galvanic or may be galvanic in addition
to the active (powered) techniques described above. For example,
germicidal ions may be generated by coupling a metal with
antimicrobial ions properties (such as silver or zinc) with another
metal to form a galvanic cell. For example, a silver wire, plating,
or film (either mechanical deposited or chemical deposited) or a
material having silver as a component of an alloy, may be placed in
contact with another metal or alloy in form of a wire, plating,
film or a component of an alloy, to create a galvanic cell that
creates and releases germicidal ions such as Pt, Pd, Au, etc. In
one variation, the device includes one or more Nitinol supports
(e.g., wires) having a silver coating connected to a conductive
component (stainless steel or Nitinol) with Pt, Pd or gold
coating.
[0107] FIG. 11A illustrates the efficacy of galvanically generated
silver ions in preventing bacterial growth (1101 clear zones in the
figure). In this example, silver wire has been wrapped with another
metal (e.g., Pt) to create a galvanic response that causes the
release of silver ions. The released silver ion results
demonstrated that bacteria were killed and bacterial growth
inhibited in a cleared area around the growing bacterial
colonies.
[0108] FIG. 11B shows a schematic of the galvanic action resulting
in silver release. In this example, the silver material 1107 (e.g.,
a reservoir of silver on an arm) is placed in electrical contact
with a galvanic reactor metal 1109. The two materials may be
surrounded by the cancellous bone and any ionic and/or conductive
material (e.g., saline, blood, cellular matrix, etc.) therein. In
general, the galvanic reactor metal 1109 in this example is
typically a more noble metal or alloy than silver (e.g., platinum).
This contact (in the conductive medium) may result in an
oxidation-reduction reaction, leading to the release of silver ions
by the galvanic reaction. This is shown in FIG. 11C, resulting in a
region surrounding the metals (within the bone, for example) of
increased silver ions by the release 1111. The released silver 1113
may diffuse or be actively driven from the cathode (silver 1107)
into the surrounding bone.
[0109] In some variations the galvanic activity/release is aided or
assisted by active (electrical) source.
[0110] Any of the treatment devices described herein may also be
retrievable. For example, the extended arms may be retracted to
remove the device. In some variations, the body of the device is
telescoping, so that it can be collapsed into the bone both to
distract the bone region, and also to allow the device to be wholly
inserted into the body and/or bone. The telescoping body may be
extended to retract the device.
[0111] The implant may be inserted quickly, but may remain in the
body for an extended period (e.g., weeks, months, years). For
example, the implant may remain implanted in a bone for a month. In
addition, the core of the implant or cartridge may be removed from
the outer telescoping body that is left within the bone and
replaced as a recharge or refreshed therapeutic unit.
[0112] The implants may be any appropriate size. For example, an
implant appropriate for spine may be smaller than the size of a
vertebral body (e.g., between 8-50 mm in diameter)
[0113] FIGS. 1A and 1B illustrate one variation of a
silver-releasing implant as described herein. FIG. 1B provides an
exploded view of the implant of FIG. 1A. In this example, the
implant 100 is configured as a telescoping implant. The body of the
implant 100 is shown in the figures. The arms 121 (which may also
be referred to as filaments or fibers) are shown extended in FIG.
1A. In some variations the devices may include additional anchoring
or securing features or members. For example, in FIGS. 1A and 1B,
the device includes a suturable material (suture ring 101) that can
be secured to a tissue to further secure the device in place. In
some embodiments, extension of the arms also secures the device in
place. In addition, the suture ring may also be impregnated with
either silver or an antimicrobial to prevent or retard infection
once sutured to the skin.
[0114] In FIG. 1B, the more distal body region 102 is telescoping,
and may be made of a durable, strong material (e.g., metal such as
titanium) to allow the body to be extended/collapsed to distract
bone or other tissue during insertion. The distal body could also
be made of a composite material such as carbon fiber or plastic to
prevent a galvanic response between the cartridge, therapeutic
wires or silver. Alternatively, the body maybe coated or formed of
a material that encourages a galvanic response to increase the
overall concentration of silver ions in the region.
[0115] The body (including telescoping segments 101, 102, and 103)
is a guide body that also includes a passageway into which the
fiber cartridge 200 may be inserted. This body passageway (fiber
outlet 103) may include one or more alignment grooves 104. The
alignment grove may be used to align the fibers so that they can be
extended out of the fiber outlets 103.
[0116] As mentioned, the device may include a fiber cartridge
within one or more (typically 2 or more) arms that include a source
of silver ions, an electrode (cathode) and a connection to the
power source. In FIGS. 1A-1B the arm shown in anti-microbial agent
(e.g., silver ion) releasing fiber. This arm includes a conductor
extending along the arm and connecting proximally to the battery or
other power source, and more distally to an electrode in contact
with a source of ions. Other examples of arms include Ag fiber, Ag
plated alloys (e.g., Nitinol), coated hollow fibers (polyimide
(etc)), as illustrated in FIGS. 4A and 4B.
[0117] In this variation, the device includes an on-board power
supply (battery 300) and electronics for controlling and/or
communicating the activity of the device, such as the applied
current and/or voltage, and the timing of the application of power
to the arms and return electrode or electrodes (not shown). The
electronics may incorporate or execute control logic for
controlling the power applied to release the silver. The
electronics may include hardware, software and firmware (for
example, the hardware may include one or more integrated circuits
for executing the control logic).
[0118] This example may also include a cap and/or spring 400 for
holding the silver-release driver (battery) and/or arms in
position. In some variations the battery and/or arms may be
replaced in an implant after it has been inserted into the bone.
For example, just the battery 300 may be replaced, or just the arms
201 may be replaced, or both may be replaced. Thus, the body (e.g.,
a telescoping body) of the device may remain in position.
[0119] FIGS. 2A and 2B show slightly enlarged views of the battery
and arms portion of the device (FIG. 2A) and the implant body (the
telescoping distal end region that includes one or more openings
from which the arms may be extended. The arms 121 may engage, and
be guided out of the outer guide body (shown in FIG. 2B) and be
deflected into their expanded (deployed) configuration, as
illustrated in FIG. 1A. The arms may be deflected into position as
the exit the ports (windows) in the guide body 103.
[0120] FIG. 3 shows one example of an array of arms 121 that may be
used. In some variations the array of arms are individually
controlled and/or connected to the power source. In other
variations each of the arms (or sub-sets of arms) are grouped
together. Thus, the arms may be extended (or retracted)
individually or in groups. As mentioned above, the arms include a
silver reservoir for release of silver ions.
[0121] FIGS. 4A and 4B illustrate two variations arms that may be
used. In FIG. 4A the arm 401 includes a core wire 403 (electrically
conductive) surrounded by a supporting metal 405 or structure. The
support structure may be nonconductive (e.g., non-conductive
polymer) of it may be conductive and insulated in parts. For
example, the arm may have a support region formed of a polymer such
as polyimide. In FIG. 4A, the conductor 403 may be a silver wire
that is used to release ions from an exposed end region 407. In
some variations the arm may include multiple release sites,
preferably all long the length of the wire. For example, the outer
region 405 may include openings or silver-ion permeable regions for
release of silver. In some variations, the wire 403 may be coupled
to another source of silver ions. In FIG. 4B the arm 401' includes
one or more passageways 411 through which additional material
(e.g., medicaments, etc.) may be passed into the body.
[0122] FIGS. 5A and 5B illustrate the device of FIGS. 1A and 1B
before extension of the arms (seen in FIG. 5A) and after extension
of the arms (seen in FIG. 5B). The arms 121 may be extended
manually by advancing the proximal end region to push the arms from
the distal end openings, as described above. In some variations the
implant may include a biasing member 503 (e.g., a spring, etc.)
holding the arms extended, and the proximal end of the implant may
be capped. The cap and bias may be applied after expansion of the
arms by an applicator (not shown) or they may be integral to the
implant at the time of insertion/deployment.
[0123] FIG. 6 illustrates a region 603 surrounding an implanted
device into which silver ions are released. In this example, the
ions are released from the arms (at one or more electrodes on the
arms) and pass into the body in an annular region around the
implant. The return electrode in this example is on the body of the
device (e.g., within or one on of the telescoping segments of the
device, or at a non-telescoping outer surface of the device.
[0124] FIG. 7 illustrates an infected region of bone 701, and FIGS.
8A-8C illustrate the implantation and operation of another
variation of an implant into this infected bone region. In this
variation a telescoping inserter (which may be configured as a
hollow body region of the implant itself) is inserted into the bone
to from a passageway into the bone for the device. The implant in
this example includes a "reverse telescoping cannula" 801 that is
inserted into the bone. For example, a relatively small hole may be
formed in the bone into the infected region so that the cannula can
be inserted. Inserting the cannula initially in the extended
(telescoping) configuration may allow the narrower distal end
(which may include one or more openings through which the arms may
be extended) to be inserted into the bone. This is shown in FIG.
8A, in which a portion of the bone has been made transparent
(appearing as a cut-out) for ease of visualization. The cannula may
form the outer (proximal) body of the device. Collapsing the
telescoping body region of the cannula may distract the bone and/or
anchor the device within the bone. An implant, including one or
more extendable arms, may be passed into the cannula so that the
arms can be extended from the distal end and into or around an
infected region of the tissue. In FIG. 8C, the telescoping cannula
(which now forms the outer portion of the implant) is collapsed
down while the arms 803 are extended into the tissue. This device
(including the telescoping region can be left in place to release
silver for the desired time period (e.g., weeks, months).
Alternatively, the telescoping region can be removed, leaving the
rest of the implant behind.
[0125] FIGS. 9-10C illustrate another variation of an implant
configured for the active release of silver ions. This example was
configured for use in the long bone (e.g., tibia, femur, etc.) of a
mammal to treat infection. Referring to FIG. 9, a schematic of the
device includes a silver-release drive (battery 901) to which a
current-regulating circuit, including resistor 903 has been
attached (by soldering in this example). The circuit is attached to
a plurality of silver wires 905 for releasing silver ions. A return
electrode (cathode 907) is connected to the opposite pole of the
battery 901. The device may include one or more anchors, such as
the anchoring rings 913, 911 shown on the power source and before
the release source (silver wires 905), respectively.
[0126] The return electrode (cathode 907) shown in this example is
a small platinum wire, however, any cathode may be used. For
example, in some variations, the anchoring ring may be the return
electrode. Alternatively, the cathode of the battery may be coated,
or merely exposed to form the return electrode in the tissue.
[0127] In some variations, the device does not include anchoring
loops, or may position the anchoring loops in other positions. For
example, anchoring loops may be positioned near or in communication
with the silver-releasing arms (e.g., wires).
[0128] An outer guide body (not shown) may be included over the
arms (wires 905) to guide the release of the wires within the bone.
The guide body may steer the wires. In variations in which the arms
have a relatively low stiffness or ability to penetrate the bone
without substantially deflection or deforming (as when the arms are
primarily unreinforced silver wires), a template or passage-forming
device may be used with the treatment implant to form the
passageways into which the arms (and/or the guide body) may be
inserted.
[0129] In the example shown in FIGS. 9 and 10A-D, the device
includes a resistor that is calibrated so that a constant current
is applied by the device. For example, a device having a 1.5
microamps of constant current has been tested in a bacterial
culture, and a 15 microamp constant current variation has also been
tested. Both examples displayed substantial antimicrobial activity,
including forming clearings or regions surrounding the
silver-releasing material in which bacteria was eliminated or
substantially eliminated. The radius of clearing was roughly
correlated with the current level. Even the very low 1.5 microamp
current device had a comparable effect compared to the 15 microamp
device, both of which produced a radius of anti-bacterial activity
that were sufficient for activity in a long bone. By including
multiple silver-releasing elements (e.g., wires) the radius may be
expanded significantly without requiring that a higher current
level be applied, potentially increasing the battery life and
effectiveness of the device.
[0130] A device such as the one shown in FIG. 9 was built and
tested, as shown in FIGS. 10A-10C. In this example, the battery was
a lithium battery (1025 Energizer.TM.). As mentioned above, any
appropriate power source may be used, including smaller or larger
batteries and external power sources. In this example, the silver
wire used was a solid silver wire (99.99% silver), forming the bulk
of the arm. As mentioned above, in some variations, the silver
reservoir of the arm may not be a wire, but may be a spike, coil,
etc., and it may be hollow, coated, or the like. For example, the
arm may be a coated Nitinol or other shape memory material.
[0131] FIG. 10C illustrates the insertion of the implant into a
rabbit femur. In this example, an implant such as the one shown in
FIGS. 9 and 10A-B includes a four-strand silver wire braided array
attached to a battery power source. The self-contained implant may
be scaled for use in infected long bones, such as diabetic foot
infections, where a diseased metatarsal may provide the implant
site, or an infected jaw (e.g., mandible). For example, the device
shown in FIG. 10B has arms having a length of approximately 5 cm.
In general, the device and systems described herein may be used in
any size-appropriate bone, and the implants may be sized or scaled
as necessary to fit the bone.
[0132] As illustrated in FIG. 10C, the device may be implanted into
a rabbit hindlimb, specifically, the mid-shaft of the tibia. In
this illustration, after surgical exposure of the tibial midshaft
region, an access hole 1005 was drilled from the outer bone layer
into the central core of the bone (medullary cavity). A
passage-forming implant device was then inserted to form
passageways for the arms to insert through. In this example, the
passage-forming implant includes one or more penetrator wires that
are passed along the intended wire treatment wire path in the
medullary bone and removed. The implant (including the array of
treatment arms) was then inserted through the hole and the
treatment arms into the passageways formed by the template
(passage-forming) device, and the treatment device was energized,
leading to continuous release of silver ions into the bone. The
remaining device components (e.g., the battery and catheter) were
then placed into a subcutaneous pocket within the hindlimb. In this
example, the wires forming the arms have been twisted to increase
their stiffness/pushability. In some variations, the arms may
include another material or structure providing
stiffness/pushability for implantation, even when used with a
template device. The arms may be placed separately (e.g., running
in different directions along the femur or other bone regions, or
wrapped around the femur, etc.).
[0133] Another variation of a treatment implant is shown in FIGS.
12A-12D. This variation illustrates a silver-releasing implant 1201
that is configured for use in a vertebra to treat osteomyelitis by
the electrically controlled release of silver ions. The implant in
this example is formed of Nitinol, and includes a core guide body
1203 and four extendable (curved) arms 1205 that may be deployed
into the bone. The deployable arms 1205 maybe rigid and
penetrating, and may be deployed, for example, into effected bony
regions. In this example (as shown in FIG. 12C) the arms are shown
extending from the core body region approximately 15 to 8 mm (some
arms are longer than others). These dimensions, including the
relative dimensions of the arms and core body region, are for
illustration only, and alternative dimensions may be used,
including alternative proportions. The core body in this example,
has an outer cylindrical region with a tapered distal end (for
penetrating bone), having a diameter of approximately 3.2 mm. In
some variations, the dimensions may be varied by +/- 5%, 7%, 10%,
15%, 25%, 50%, 100%, 200%, etc of the values shown. In addition,
the arms may extend from the core body region in a pattern that is
not uniform around the circumference of the implant, as shown in
FIG. 12B, showing an end view of the implant. In this example,
multiple arms extend out from the core guide body on only one side
of the implant (four arms are shown, all extending in the upper
140.degree. region).
[0134] In general, when a material such as Nitinol is used, it may
be desirable to coat or treat the silver to be released onto the
Nitinol frame. This is typically done by removing the passivation
coating of titanium oxide on the Nitinol, which might otherwise
prevent adhesion of the silver. To prevent exposure of the tissue
to nickel, which may be undesirable, the nickel titanium alloy may
be coated with an adhesion layer that may both passivate the nickel
titanium and help adhere any silver coatings to the arms. In some
variations described herein, the Nitinol may be coated or plated
with an inert metal (including a conductive metal) first before
plating the silver (and after removing any titanium oxide layer).
Thus, the Nitinol structures (arms) including a silver reservoir
may be covered with inert or biocompatible metal (e.g., gold,
platinum, etc.) to encase the Nitinol, which is then coated with
the appropriate silver layer. In one example, a silver-plated
implant was formed by a Nitinol structure to which a gold layer was
first plated followed by a silver layer.
[0135] FIGS. 13A-13E show another variation of an implant 1300 for
insertion into a bone to treat infection. In this variation, the
arms are slats or slat-like members that are inserted by sliding
axially against a guide member and/or against each other in the
distal direction; as they are slid distally, the distal ends are
deflected by a deflection member (e.g., a ramp or other guide
region) that is present on the guide member and on the adjacent
arm(s). The arms may be collected together but able to slide
axially. In some variations, the guide member may be removable
after insertion of the arms, of it may be left in position within
the bone, helping to hold the arms securely in position.
[0136] For example, in FIG. 13A, the implant includes a plurality
of arms 1301, an elongate and rigid guide member 1303, and a
delivery device 1305. Each of the arms 1301 is configured as an
elongate member with an approximately rectangular cross-section.
The arms are all configured to slide against adjacent arms or
against the guide member. In general, these arms may be configured
to conform to the adjacent arms or the guide member. In the example
shown in FIG. 13A, the arms have flat surfaces that are configured
to slide against adjacent flat surfaces on the adjacent arms or the
guide member. In other variations, the arms may present curved or
rounded surfaces. In some variations, the arms may include bearing
surfaces (which may include additional bearing structures between
adjacent arms facilitating axial motion between the arms). The arms
typically include a deflectable distal region at the distal ends of
the arms 1309, although the entire arm may be deflectable, or just
a region (e.g., a hinge region proximal to the distal end) may be
deflectable. The arms may be formed of a metal, composite, polymer,
or the like (including combinations thereof). One or more
reservoirs of silver are located on each of the arms. Silver
reservoir(s) may be coatings. The silver reservoir may be exposed
along all or a portion of the length, or in one or more discrete
regions along the length. These silver-release sites may be on one
or more sides of the arm. In FIG. 13A, each arm includes a
deflection ramp 1311. The delivery device 1305 includes an
attachment region at the distal end that is threaded for engagement
with the proximal end of the guide member of the implant.
[0137] FIG. 13A is an exploded view of the implant. FIGS. 13B-13E
illustrate one variation of a method for implanting the treatment
implant shown in FIG. 13A. For example, in FIG. 13B, the elongate
guide member 1303 is inserted into a bone. In this example, the
bone is first pre-drilled to form a channel 1324 approximately the
same size (or slightly larger) than the guide member 1303, through
the cortical bone 1326 and into the intramedullary space (e.g.,
cancellous bone) 1322. The proximal end of the guide member 1303 is
shown coupled to the distal end of the insertion device 1305. In
FIG. 13C, the first arm member 1331 has been slid axially along the
guide member and into the bone (beyond the cortical bone region
1326). The insertion device 1305 may include a pusher element that
pushes the arm axially (distally) along the guide member. As the
arm is driven distally, the distal end of the arm 1331 contacts the
deflection member 1313, which deflects the distal end of the arm
away from the long axis of the guide and into the cortical bone
1322. The distal end of the arm may be sufficiently sharp and/or
tissue penetrating and/or the arm may have sufficient column
strength, so that driving the arm distally pushes the distal end of
the implant along a curved pathway into the cortical bone, as
shown. The proximal end of the arm may be pushed beyond the
cortical bone and into the intramedullary space, as shown in FIG.
13C.
[0138] Thereafter, additional arms may be inserted by sliding
distally, as shown in FIG. 13D. For example, each arm may be pushed
over the delivery device (1305) using a pusher (which may be part
of the device) to engage and push the proximal end of each arm. As
it is slid distally, each arm may be slid along over the previous
arm. The previous arm may therefore have a gently sloped proximal
end (not shown) to allow gradual loading onto the arm by a new arm;
each of the previous arms also typically includes a deflection
element (e.g., a ramp or protrusion) that deflects the distal end
of the adjacent arm being loaded in a curved pathway through the
bone. The deflection element may be positioned at some portion of
the upper surface of the adjacent arm. In some variations the arms
have decreasing lengths so that they all end (when fully implanted)
near about the same proximal portion of the implant; in other
variations the proximal ends are staggered so that the
later-applied arms terminate more distally or more proximally (as
shown).
[0139] FIGS. 13A-13D illustrate an implant that project (in the
delivered configuration) into the bone from only one side of the
guide member. In some variations, the device may be configured to
project into the bone in different directions (e.g., on the bottom
of the inserter in FIG. 13D). The variation shown in FIGS. 14A-14C
illustrates one embodiment of this.
[0140] Once inserted, the implant may be activated (or may be
inserted in the activated configuration) to release silver over
time. For example, a silver-release driver may be coupled to each
arm to drive release of silver from the silver reservoirs on each
arm. In some variations a single electrical drive (e.g, power
source) is located within the guide member and electrical contact
is made with each silver reservoir (not shown). For example,
electrical contact may be made through the deflection members that
may engage complimentary electrical contacts on the bottom of each
arm when inserted into the bone. In some variations each arm is
separately coupled to an individual silver-release driver. For
example, the silver reservoir on each arm may be coupled to a
galvanic reactor metal or a power source driving release of silver
ions.
[0141] In some variations, the implant includes a collar or link
around or between the arms, holding them together, even as they are
axially movable or slideable relative to each other. For example,
one or more collars may collect the implant arms together. The
collar may also hold the guide member relative to the arms. The
collar may be coupled to the silver-release driver.
[0142] FIG. 13E illustrates one method of removing the implant of
FIG. 13A. In this variation, the guide member may be removed from
the bone leaving a passage from which each arm 1301 can be
withdrawn. A removal tool (e.g., having a grasper or engager to
couple with the proximal end of each arm or a plurality of arms)
may be used to remove the arms and thus the implant.
[0143] FIGS. 14A-14D show another variation of an implant having
arms including a deflection member along their length for
deflection of adjacent arms as the arms are inserted axially. FIG.
14A shows an exploded view of the implant 1400, including a
plurality of arms 1401, a guide member 1403. A portion of an
inserter 1405 is also shown. FIG. 14B illustrates the implant
assembled and in a deployed configuration, with the arms extending
outwards. In this variation, three sets of arms are shown, each
with at least one silver reservoir for release of silver (not
shown). Each set is configured so that the arms may be extended
axially to project the arms into the bone and be stacked and slid
relative to each other so that the more radially (outer) arms are
deflected by the adjacent arms. In FIG. 14C, an end view of the
deployed implant shown a variation in which the arms are grouped
into three sets positioned around the perimeter of the centrally
located guide member. In this variation, the arms are stacked atop
one another. An alternative deployed configuration is shown in FIG.
14D, in which the more outwardly-located arms in each set are
staggered slightly along the perimeter of the guide member. This
configuration may provide a slightly broader expanse of arms in the
deployed configuration. As mentioned above, adjacent arms may be
configured to slideably mate; in some variations the configuration
may allow for both the radially outward deflection, expanding the
arms into the bone, and they may also drive them to be offset
around the circumference as shown in FIG. 14D. For example, the
upper surface may include a track or lateral deflector.
[0144] FIGS. 15A-15C illustrate another variation of an implant
1500 similar to that shown in FIGS. 13A and 14A; a portion of an
insertion device 1509 is also shown. In this example, the guide
member 1507 includes a spiral-shaped deflection region 1503. Two
sets of arms 1503, 1505 are included, each set including a silver
reservoir (not shown). The first set 1505 also includes a
deflection element (e.g., ramp) along its length. The second set of
arms 1503 may be slid distally along arms of the first set 1505.
FIG. 15B shows the implant after deployment of the first set 1505
of arms over the guide member 1507. FIG. 15C shows the implant
after deployment of the second set 1503 of arms over the guide
member 1507 and the first set of arms 1505.
[0145] FIGS. 16A-16C illustrate another variation of an implant
having a plurality of deflectable arms that are extended from the
implant by a deflection element on the guide member 1601. In this
variation, the implant includes a guide member 1601 having a
deflection member configured as an annular ring 1603. The arms 1605
are arranged around the perimeter of the guide member in two
concentric rings, as shown in the cross-sectional view of FIG. 16C.
Each arm is axially slideable distally, relative to the guide
member 1601 and/or an adjacent arm. In some variations the implant
in the undeployed (e.g., delivery) configuration has the arms
pre-arranged around the central guide member 1601. The arms may be
collared or otherwise secured to hold them around the circumference
of the guide member, while allowing them to extend axially for
deployment and expansion by deflection over the deflection element
1603 located distally on the guide member 1601. To deploy the arms
of the guide element (e.g., within the bone), the rings of arms may
be collectively or individually slid distally, axially along the
length of the inner guide member 1601.
[0146] In any of the variations shown in FIGS. 13A, 14A, 15A and
16A, the arms and the guide member may be coupled together in the
undeployed configuration, or they may be unassembled until they are
being deployed. Also, in any of these variations any of the
elements previously described (including the silver-release driver)
may be included. These devices may also be removed from the bone,
as mentioned above.
[0147] In some variation, the device may be configured so that,
upon removal from the bone, they automatically remove or sample a
region of the bone (e.g., by "coring" a portion of the bone). Any
samples removed may be examined to determine the effect of the
implant, including determining the presence or absence of
infection. For example, in some variations the guide member or the
arms, or some other portion of the device, includes a coring
element that is oriented so as to remove a tissue sample (e.g.,
bone sample) when the implant or portion of the implant, is
removed. FIGS. 17 and 18 illustrate variations including sampling
members.
[0148] FIG. 17 shows a variation of an arm having a two sampling
regions 1701, 1703. This arm, or a plurality of similar arms, may
be included in any of the variations described above, particularly
those shown in FIGS. 13A, 14A, 15A and 16A. For example, the
outermost (radially) arm in any of these variations may include the
sampling arm shown in FIG. 17. Withdrawing the sampling arm
proximally from the bone may result in removing of a sample (core)
that is collected into the sampling regions 1701, 1703.
[0149] In FIG. 18, another variation of an implant is shown in
which the arms have been extended into the deployed configuration
into a bone. In this variation, the implant includes a plurality of
sampling elements 1801 on many (if not all) of the arms and the
guide member.
[0150] FIGS. 19A-19L illustrate another variation of a system
including a treatment implant and a template or passage-forming
device for pre-forming the passageways through the bone into which
the arms of the treatment implant will be inserted. FIG. 19A shows
an exploded view of the system 1900, including a plurality of arms
1901, a guide member 1905 and a pre-bore stylus 1907. The pre-bore
stylus is the passage forming device that may be used with the
guide member to form the passageways into the bone in which the
arms 1901 may be inserted.
[0151] In this example, the guide member is a rigid elongate member
(although non-rigid members may be used) that includes multiple
guide regions, such as channels, along the device for directing the
implant's silver-releasing arms out of the device. In the example
shown in FIG. 19A, these guide regions are open channels, as
illustrated in the cross-sections through the guide member in FIGS.
19B and 19C. In an alternative embodiment, these channels may be
closed channels, as shown in alternative cross-sections 19D and
19E.
[0152] In operation, the system may be used as illustrated in FIGS.
19F-19L. Initially an insertion channel may be drilled into the
bone, and the guide member inserted. The guide member may be
anchored into position in the bone. For example, the guide member
may have extendable anchors (not shown). In some variations the
guide member may be secured (e.g., so that it doesn't move or
rotate relative to the bone once secured) in the channel at the
proximal end, for example at the cortical bone entry site or to the
outside of the bone. In some variations, the guide member is
secured within the bone by a bone cement. In some variations
(similar to that shown in FIGS. 19A-19I), the implant guide member
is coupled to an insertion tool 1925 and the insertion tool may be
anchored rather than (or in addition to) the guide member 1905. The
anchoring may be releasable so that all or a portion of the implant
(or the insertion tool) may be released from the bone for
removal.
[0153] As illustrated in FIG. 19F, once the guide member is in
position within the bone 1922 (past the cortical bone 1926) in a
central channel 1924, channels into the bone for the placement of
the arms 1924' may be formed using the elongate pre-bore stylus. In
FIG. 19F, a single pre-bore stylus may be driven along each pathway
through the guide member to form a channel for each arm.
Alternatively, a pre-bore stylus may have multiple tissue (bone)
penetrating members that can be guided into the bone to form the
passageways. The pre-bore stylus may be a bone-penetrating member
having a sufficient column strength to penetrate the bone. In some
variations it may be a cutting tool, including electrical cutting
tool (e.g., electrosurgical), or a drilling tool. The diameter of
the pre-bore stylus or other template device channel-forming
component may be approximately the same or slightly smaller than
the diameter of the arms, or in some variations, larger.
[0154] Once the channels have been formed, as illustrated in FIG.
19G, the implant's silver-releasing arms may be inserted. The arms
may be individually inserted (as shown in FIGS. 19H-19I), or they
may be inserted all together, in variations in which the arms are
coupled together. The guide may then direct the arms as they are
each slid distally in the guide channel(s) through the channels
formed by the template channel-forming tool, until they are fully
extended, as shown in FIG. 19I.
[0155] In some variations the implant is coupled to an inserter
1925 for insertion. In the variation shown in FIGS. 19A-19I, the
insertion device is shown partially illustrated and coupled to the
guide member. The inserter extends the guide channels of the guide
member. In FIG. 19J, the inserter is removed from the proximal end
of the implant, and the implant may be left in position. The hole
into the bone may be filled or capped, although access may be left
available to retrieve or alter the implant later. The extended arms
may help anchor the device in place, though it may be removed in
whole or in part, as illustrated in FIGS. 19K and 19L.
[0156] In FIG. 19K, the entire implant is removed by again coupling
the proximal end of the guide member to an inserter device, or to a
removal device that is complementary to the coupling region on the
proximal end of the inserter, and drawing the implant proximally
out of the bone.
[0157] Alternatively, in one variation, as shown in FIG. 19L, the
individual (or a group of) the arms may be removed using an arm
removal device. In the example shown in FIG. 19L, the guide member
has been separately removed, although in some variations, the guide
member may be left in position. An arm removal device may include a
coupling region that couples to the proximal end of an arm or a
group (including all) of the arms. In FIG. 19L the implant arms
include a ball region at their proximal ends, and the removal
device includes a coupling member that clamps or otherwise grasps
the proximal end.
[0158] Another example of a silver-releasing implant is shown in
FIGS. 20A and 20B. In this example, the implant includes a guide
member 2003 having a plurality of guide channels and openings 2007
at various positions along its length. The guide member may be
inserted into the bone channel 2012 as described above, and the arm
assembly 2001 including a plurality of silver-releasing arms (e.g.,
arms having silver depots) may be inserted into the guide member so
that the arms are guided along the length of the guide member and
out into the bone from various positions and at various angles
relative to the guide member, as illustrated in FIG. 20B. The
proximal end of the arm assembly in this example includes a housing
that may include the silver-release driver. The housing may also be
configured to couple to an inserter/remover (not shown), including
a releasable attachment region (e.g., a threaded attachment region,
a snap-fit attachment region, etc.). In some variations, the distal
end of the housing also includes an attachment region for mating
with the distal end of the guide member.
[0159] In some variations the treatment implant includes a
replaceable or rechargeable silver-release driver. For example,
FIGS. 21A-21D illustrate an system 2100 including an implant having
a guide member 2103, a plurality of silver-releasing arms 2101, and
an endpiece 2105 that includes a power supply for driving release
of the silver ions. The endpiece 2105 may include a flange rim 2097
securing it to the bone surface, as well as an attachment site 2111
for coupling to the implant (e.g., the plurality of arms). The end
piece may be secured to the implant once it has been placed and
expanded using an inserter, as mentioned above. The end piece may
also include an access 2109 for a batter replacement, such as a
cartridge, door, panel, etc.
[0160] FIG. 21B illustrated the variation shown in FIG. 21A after
implantation into the bone, in which the arms 2102 have been
extended from the guide member. FIG. 21C shows a cross-section
through the implant, schematically illustrating the electrical
connections to the arms 2102 and the battery element 2121. FIG. 21D
illustrates an alternative embodiment, in which the silver release
driver 2117 is insertable within the device (e.g., the housing 2125
of the plurality of arms).
[0161] In some variations the arms of the implant may be
controllably extendable/expandable from the implant guide member by
activation of a control element. For example, in FIGS. 22A and 22B,
one variation of a silver-releasing implant is shown in which the
arms of the implant are configured to be extended from a guide body
2203 by rotation of an internal extension/retraction mechanism 2205
to push (or pull when retracting) the arms 2207 from the guide
member and into the bone. In this example, a tool (an extension
tool) 2212 may be used to turn the internal mechanism. The internal
mechanism is shown as an Archimedes-screw type mechanism that
drives linear motion (forward/backward axially) of the plurality of
silver-releasing arms. Other variations may also be used to control
extension and/or retraction of the arms. In some variations an
external tool is not required, and the device automatically (or
under remote control) extends or retracts the arms. The arms may be
fully extended from the guide member, or they may be gradually
extended to gradually expose more silver (or to replenish depleted
silver from the distal ends of the arms).
[0162] As mentioned above, in some variations the implants maybe
removed in whole or in part from the bone. In some variations, the
insertion tool or device may also be used to remove the implant. In
some variations a separate or dedicated removal device may be
provided. For example, FIG. 23 illustrates one variation of a
removal device. In general, a removal device may include a pair of
engagement regions for individually engaging both the guide member
of the implant and the plurality of arms of the implant. In FIG.
23, an outer engagement member 2302 is configured to engage the
guide member at the proximal end of the guide member, while an
inner engagement member is configured to engage the plurality of
arms. In this example the engagement members are clamps or jaws
that controllably engage either the guide member or the plurality
of arms. Other engagement members may be used for coupling with
complimentary coupling regions on the implant. As illustrated
above, the coupling region on the guide member and a coupling
member on the plurality of arms may be a threaded region that
engages a threaded member(s) on the removal device. Threaded
regions on the plurality of arms and the guide member may be
oppositely threaded.
[0163] In the exemplary device shown in FIG. 23, the inner coupling
member (engagement member 2304) for coupling to the plurality of
arms may be separately controlled relative to the outer coupling
member (engagement member 2302) for coupling to the guide member,
allowing the retraction and possibly removal of the arms relative
to the guide member. In operation, the removal device may move the
arms relative to the guide member (leveraging off of the guide
member) to collapse the arms.
[0164] FIGS. 24A-24E illustrate removal of another variation of a
silver-releasing implant. In this example, the implant has been
inserted into the bone and a plurality of arms extended into the
bone. The arms 2403 extend from the distal end of the housing/guide
member 2405. In FIG. 24A, the plurality of arms are coupled
together in an inner member 2407 that can be advanced/retracted
within the guide member 2405. The proximal end of the inner member
includes a coupling region (threaded in this example), while the
proximal end of the outer member (the guide member 2405) also
includes a coupling region. In this example, a removal device 2424
includes an inner coupling member 2426 for coupling to the
plurality of arms at the coupling region on the inner member 2407.
The removal device also includes an outer coupling member 2428 for
coupling to the guide member 2405. It should be noted that in some
variations the role of the outer and inner members may be reversed
(e.g., the outer member may couple to the plurality of arms and the
inner member may couple to the guide member). In some variations
the two coupling members are not arranged concentrically, but are
arranged side-by-side.
[0165] In FIG. 24B the outer coupling member has been coupled to
the threaded region on the guide member. FIG. 24C shows the
coupling of the inner member to the plurality of arms. The
plurality of arms can then be drawn proximally, withdrawing them
from the bone, as shown in FIG. 24D. Finally, in FIG. 24E the
entire implant can be withdrawn. Once removed, the opening may be
sealed or filled, or a new implant may be inserted.
[0166] FIGS. 25-28B illustrate different coupling regions and means
for coupling that may be used between the implant regions and the
insertion or removal devices, or between regions of the implant.
For example, in FIG. 25, the coupling region is a threaded region.
FIGS. 26A and 26B illustrates a coupling region that is configured
as a friction-engagement region in which the inner member is
captured by an outer member and compression fit to secure the two
ends together. Similarly, in FIGS. 27A and 27B the coupling means
illustrated in FIGS. 26A and 26B is shown for use to expand an
inner member 2701 within a surrounding outer member 2704. The inner
member 2701 may include or be used with a brace, anchor or other
structure that prevents it from moving (e.g., axially) during
expansion. For example, a cylinder, rim, or lip (not shown)
adjacent to the inner member may be used to brace the inner member
during expansion. A mechanism such as this may be used to expand
the plurality of arms from the implant. FIGS. 28A and 28B
illustrate another variation of an engagement member in which the
flanges on the inner member are compressible but allowed to expand
once they reach the engagement region in the outer member and are
allowed to expand, connecting the two regions.
[0167] FIGS. 29A-29D illustrate one variation of a silver-releasing
arm. In some variations the silver-releasing arm may be flexible,
as shown in FIGS. 29A and 29B. The arm may include an inner silver
depot 2901 and an outer protective cover 2903 having one or more
openings 2905 from which silver may be released, as illustrated in
FIG. 29B. In some variations the arms may be relatively stiff. The
outer protective cover may be a metal, polymer, or the like. In
some variations the arms include a shape memory material, such as a
shape memory alloy, that may be pre-biased into a shape (curved,
etc.). FIGS. 29C and 29D show enlarged and cross-sectional views,
respectively, of a portion of the arm shown in FIGS. 29A-29B. In
some variations the arm is not hollow or silver-filled, as shown in
FIGS. 29A-29D, but instead is coated with silver to form the silver
reservoir.
[0168] Although many of the variations described herein include a
plurality of expandable arms, providing many of the advantages
described above (such as reaching large bone regions), in some
variations it may be desirable to use a single arm, as illustrated
in FIGS. 30A and 30B. In this example, the flexible arm shown in
FIGS. 29A-29D is used as an inner arm member in conjunction with an
outer member (e.g., guide) for insertion in to the bone. The inner
arm 3001 (including an internal silver reservoir 3003) may be
extended from the outer member 3005 to drive it into the bone as
illustrated in FIG. 30B. In operation, the inner member is extended
from the outer member after the outer member has been inserted into
the bone; the outer member is released while withdrawing it
proximally, and the inner member is fed through it and into the
bone.
[0169] FIGS. 31A-31C illustrate another variation of a
silver-releasing arm that may be used. In this example, the arm
includes an inner core of silver 3101 that is surrounded by an
outer covering or scaffold 3105. In the outer covering includes
openings, as seen in FIG. 31B through which the silver may be
released. In any of the device variations described herein the
silver released from the arms may be directly released (e.g., a
silver surface may be exposed to the bone), or it may be released
into a buffer or matrix through which it may move on its way into
the bone.
[0170] In one variation, the implant may include just the arms,
which may be inserted into the bone, as shown in FIG. 31C. In this
variation each arm 3107 may include a silver release driver (such
as a power source and/or a galvanic reactor metal in electrical
contact with the silver reservoir).
[0171] In some variations, the implant may include a liquid
reservoir for delivery of a therapeutic material, which may include
a solution of silver, into the bone. For example, FIG. 32A
illustrates one variation of an implant having a plurality of
fluid-delivery arms 3205 that are hollow and connected to a source
of therapeutic fluid 2307. FIG. 32B shows a cross-section through
the fluid delivery arms of the device.
[0172] Although illustrative variations of the present invention
have been described above, it will be evident to one skilled in the
art that various changes and modifications may be made without
departing from the invention. For instance, variations of the
present invention may include the release of other (including other
ionic) antimicrobial, growth hormone, other drug, or the like. In
addition, the present invention may include the use of the
procedures described herein for therapy, repeating the procedures
as often as necessary, as the amount or placement of the implant
may change over time.
* * * * *