U.S. patent application number 17/829053 was filed with the patent office on 2022-09-15 for systems and methods for monitoring wound closure.
The applicant listed for this patent is Smith & Nephew PLC. Invention is credited to Allan Kenneth Frazer Grugeon Hunt.
Application Number | 20220287591 17/829053 |
Document ID | / |
Family ID | 1000006364573 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220287591 |
Kind Code |
A1 |
Hunt; Allan Kenneth Frazer
Grugeon |
September 15, 2022 |
SYSTEMS AND METHODS FOR MONITORING WOUND CLOSURE
Abstract
Embodiments disclosed herein relate to systems, devices and
methods for monitoring dimensional changes in medical devices
attached to or implanted in the body, such as wound fillers.
Disclosed embodiments may facilitate measuring the degree of wound
closure by incorporating conductive elements into the wound filler.
In some embodiments, the conductive elements may be conductive
filler, a flexible conductive element, or an arrangement of
discrete non-flexible conductive elements. The density of
conductive material in an area or volume of the wound filler upon
wound closure may be detected by a detection device that assesses
the local dielectric constant of the wound filler, such as through
use of a capacitive plate, or by a detection device that measures
the resonant frequency of a conductive element.
Inventors: |
Hunt; Allan Kenneth Frazer
Grugeon; (Beverley, GB) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Smith & Nephew PLC |
Watford |
|
GB |
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|
Family ID: |
1000006364573 |
Appl. No.: |
17/829053 |
Filed: |
May 31, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16641964 |
Feb 25, 2020 |
11375923 |
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PCT/EP2018/072296 |
Aug 17, 2018 |
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17829053 |
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62551646 |
Aug 29, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 1/90 20210501; A61M
2205/3317 20130101; A61B 5/1109 20130101; A61F 13/00068 20130101;
A61M 2205/702 20130101; A61F 2013/00357 20130101 |
International
Class: |
A61B 5/11 20060101
A61B005/11; A61F 13/00 20060101 A61F013/00; A61M 1/00 20060101
A61M001/00 |
Claims
1-20. (canceled)
21. A wound therapy system comprising: a wound filler configured to
be at least partially inserted into a wound, the wound filler
comprising a conductive element; and a detection device configured
to assess a degree of wound closure based on a measurement of the
dielectric constant of the wound filler, wherein the dielectric
constant changes based on a compression of the wound filler.
22. The system of claim 21, wherein the conductive element
comprises a conductive filler embedded in the wound filler.
23. The system of claim 21, wherein the conductive element
comprises a plurality of conductive elements spaced across the
wound filler.
24. The system of claim 21, wherein: the wound filler is configured
to be compressed in a first direction and not substantially
compressed in a second direction, the second direction being
perpendicular to the first direction; the conductive element
comprises a plurality of conductive wires, each conductive wire
comprising a length extending from a first end to a second end; and
the conductive wires are arranged substantially parallel to one
another and so that the lengths of the conductive wires extend
along the second direction.
25. The system of claim 21, wherein the conductive element
comprises a substantially flexible conductive element.
26. The system of claim 25, wherein the substantially flexible
conductive element comprises a conductive strip having a width
defining a lateral dimension and a length defining a longitudinal
dimension, the conductive strip comprising a conductive wire
including a plurality of bends spaced across the length of the
conductive strip, wherein at least some of the bends are configured
to allow the conductive strip to be compressed or extended along
the longitudinal direction such that the density of the conductive
wire is increased or decreased along at least a portion of the
longitudinal dimension.
27. The system of claim 25, wherein the measurement comprises a
measurement associated with the resonant frequency of the flexible
conductive element.
28. The system of claim 26, wherein the plurality of bends forms a
sinusoidal, serpentine, and/or triangular pattern.
29. The system of claim 21, wherein one or more fixed density
conductive elements are coupled to the wound filler, and wherein
the density of the one or more fixed density conductive elements
does not substantially change upon compression of the wound
filler.
30. The system of claim 29, wherein the detection device is
configured to be calibrated based on the measurement of a detection
area comprising the fixed density conductive element.
31. The system of claim 1, further comprising a negative pressure
source configured to provide negative pressure to a wound, the
negative pressure source configured to be in fluid communication
with the wound filler.
32. A method for assessing a degree of wound closure of a wound,
the method comprising: placing a detection device in proximity of a
wound filler at least partially inserted into a wound, the wound
filler comprising a conductive element; and using the detection
device to make a measurement based on the dielectric constant of
the wound filler, wherein the dielectric constant changes based on
a compression of the of the wound filler.
33. The method of claim 32, further comprising calibrating the
detection device by using the detection device to take a
calibration measurement over an area of the wound filler comprising
a fixed density conductive element, wherein a density of the fixed
density conductive element does not change upon compression of the
wound filler.
34. The method of claim 32, further comprising relating the
measurement to a degree or amount of wound closure.
35. A method for assessing a degree of wound closure of a wound,
the method comprising, by a detection device: making a measurement
of the dielectric constant of a wound filler at least partially
inserted into the wound, the wound filler comprising a conductive
element coupled to the wound filler; and based on the measurement,
indicating a degree of compression of the wound filler.
36. The method of claim 35, wherein making the measurement
comprises applying a voltage to one or more capacitive plates
within the detection device, wherein the amount of charge stored on
the one or more capacitive plates is configured to be modulated by
a dielectric constant of the detection area, and wherein the
measurement is reflective of the amount of charge stored on the one
or more capacitive plates.
37. The method of claim 35, wherein the conductive element is a
flexible conductive strip having a width defining a lateral
dimension and a length defining a longitudinal dimension, the
flexible conductive strip comprising a conductive wire comprising a
plurality of bends spaced across the length of the flexible
conductive strip, wherein at least some of the bends are configured
to allow the flexible conductive strip to be compressed or extended
along the longitudinal direction such that the density of the
conductive wire is increased or decreased along at least a portion
of the length of the flexible conductive strip; and wherein making
the measurement comprises transmitting a radio wave toward the
flexible conductive strip, receiving a radio wave transmitted from
the direction of the flexible conductive strip, and measuring the
resonant frequency of the flexible conductive strip, the resonant
frequency being dependent upon the degree of compression
experienced by the flexible conductive strip.
38. The method of claim 35, wherein the conductive element
comprises a conductive filler embedded in the wound filler.
39. The method of claim 35, wherein the conductive element
comprises a plurality of conductive elements spaced across the
wound filler.
40. The method of claim 35, further comprising connecting a
negative pressure source in fluid communication with the wound
filler.
Description
BACKGROUND
Field
[0001] This application describes embodiments of apparatuses,
methods, and systems for the treatment of wounds, specifically for
the measurement of the amount of wound closure.
Description of the Related Art
[0002] Negative pressure wound therapy has been used in the
treatment of wounds, and in many cases can improve the rate of
healing while also removing exudates and other deleterious
substances from the wound site.
[0003] Abdominal compartment syndrome is caused by fluid
accumulation in the peritoneal space due to edema and other such
causes, and results in greatly increased intra-abdominal pressure
that may cause organ failure eventually resulting in death. Causes
may include sepsis or severe trauma. Treatment of abdominal
compartment syndrome may require an abdominal incision to permit
decompression of the abdominal space, and as such, a large wound
may be created onto the patient. Closure of this wound, while
minimizing the risk of secondary infections and other
complications, and after the underlying edema has subsided, then
becomes a priority. However, acute open abdominal conditions may be
caused by other reasons in addition to compartment syndrome, as
described further below.
[0004] Other large or incisional wounds, either as a result of
surgery, trauma, or other conditions, may also require closure. For
example, wounds resulting from sterniotomies, fasciotomies, and
other abdominal wounds may require closure. Wound dehiscence of
existing wounds is another complication that may arise, possibly
due to incomplete underlying fascial closure, or secondary factors
such as infection.
[0005] Existing negative pressure treatment systems, while
permitting eventual wound closure, still require lengthy closure
times. Although these may be combined with other tissue securement
means, such as sutures, there is also a risk that underlying
muscular and fascial tissue is not appropriately reapproximated so
as to permit complete wound closure. Further, when foam or other
wound fillers are inserted into the wound, the application of
negative pressure to the wound and the foam may cause atmospheric
pressure to bear down onto the wound, compressing the foam downward
and outward against the margins of the wound. This downward
compression of the wound filler slows the healing process and slows
or prevents the joining of wound margins. Additionally,
inflammation of the fascia in the form of certain types of
fasciitis can lead to rapid and excessive tissue loss, potentially
meriting the need for more advanced negative pressure treatment
systems. Accordingly, there is a need to provide for an improved
apparatus, method, and system for the treatment and closure of
wounds.
SUMMARY
[0006] Disclosed embodiments relate to systems, devices, and
methods for assessing dimensional changes in medical devices
implanted into or attached to a human or animal body. The medical
device can be a wound filler and the assessment of dimensional
changes may provide a measurement of the degree of wound closure as
the wound filler is compressed by the closing wound.
[0007] In some embodiments, a wound therapy system comprises a
wound filler configured to be at least partially inserted into a
wound; a conductive element coupled to the wound filler, wherein a
density of the conductive element increases within a detection area
of the wound filler upon compression of the wound filler; and a
detection device configured to assess a degree of wound closure
based on a measurement of the density of the conductive element in
the detection area, wherein the density is dependent on the amount
of compression of the wound filler.
[0008] The system of the preceding paragraph can be used with any
of the following features. The measurement may comprise a
measurement of the dielectric constant of the detection area of the
wound filler, wherein the dielectric constant changes based on a
compression of the wound filler.
[0009] The system of any of preceding paragraphs can be used with
any of the following features. The conductive element may be a
conductive filler embedded at least in the detection area of the
wound filler.
[0010] The system of any of preceding paragraphs can be used with
any of the following features. The conductive element may be a
plurality of conductive elements spaced across at least the
detection area of the wound filler.
[0011] The system of any of preceding paragraphs can be used with
any of the following features. The wound filler may be configured
to be compressed in a first direction and not substantially
compressed in a second direction, the second direction being
perpendicular to the first direction. The conductive element can be
a plurality of conductive wires, each conductive wire comprising a
length extending from a first end to a second end. The conductive
wires can be arranged substantially parallel to one another and so
that the lengths of the conductive wires extend along the second
direction.
[0012] The system of any of preceding paragraphs can be used with
any of the following features. The conductive element may be
substantially flexible.
[0013] The system of any of preceding paragraphs can be used with
any of the following features. The substantially flexible
conductive element can be a conductive strip having a width
defining a lateral dimension and a length defining a longitudinal
dimension. The conductive strip may comprise a conductive wire
including a plurality of bends spaced across the length of the
conductive strip. At least some of the bends can be configured to
allow the conductive strip to be compressed or extended along the
longitudinal direction such that the density of the conductive wire
is increased or decreased along at least a portion of the
longitudinal dimension.
[0014] The system of any of preceding paragraphs can be used with
any of the following features. The measurement may comprise a
measurement of the resonant frequency of the flexible conductive
element.
[0015] The system of any of preceding paragraphs can be used with
any of the following features. The bends may form a sinusoidal,
serpentine, and/or triangular pattern.
[0016] The system of any of preceding paragraphs can be used with
any of the following features. One or more fixed density conductive
elements can be coupled to the wound filler, wherein the density of
the one or more fixed density conductive element does not
substantially change upon compression of the wound filler.
[0017] The system of any of preceding paragraphs can be used with
any of the following features. The detection device can be
configured to be calibrated based on the measurement of a detection
area including the fixed density conductive element.
[0018] The system of any of preceding paragraphs can be used with
any of the following features. The system can include a negative
pressure source configured to provide negative pressure to a wound.
The negative pressure source may be configured to be in fluid
communication with the wound filler.
[0019] In some embodiments, a method for assessing a degree of
wound closure of a wound comprises placing a detection device in
proximity of a detection area of a wound filler. The wound filler
may include a conductive element coupled to the wound filler,
wherein a density of the conductive element increases within the
detection area of the wound filler upon compression of the wound
filler. The method further comprises using the detection device to
make a measurement based on the density of the conductive element
in the detection area, wherein the density is dependent on the
amount of compression of the wound filler.
[0020] The method of any of preceding paragraphs can be used with
any of the following features. The method can further comprise
calibrating the detection device by using the detection device to
take a calibration measurement over an area of the wound filler
comprising a fixed density conductive element. A density of the
fixed density conductive element does not change upon compression
of the wound filler.
[0021] The method of any of preceding paragraphs can be used with
any of the following features. The method may further comprise
relating the measurement to a degree or amount of wound
closure.
[0022] In some embodiments, a method for assessing a degree of
wound closure of a wound by a detection device comprises making a
measurement within a detection area of a wound filler at least
partially inserted into the wound. The wound filler includes a
conductive element coupled to the wound filler, wherein a density
of the conductive element increases within the detection area of
the wound filler upon compression of the wound filler comprising
the detection area. The method further comprises, based on the
measurement, indicating a degree of compression of the wound
filler.
[0023] The method of the preceding paragraph can be used with any
of the following features. Making the measurement may comprise
applying a voltage to one or more capacitive plates within the
detection device, wherein the amount of charge stored on the one or
more capacitive plates is configured to be modulated by a
dielectric constant of the detection area and wherein the
measurement is reflective of the amount of charge stored on the one
or more capacitive plates.
[0024] The method of any of preceding paragraphs can be used with
any of the following features. The conductive element may be a
flexible conductive strip having a width defining a lateral
dimension and a length defining a longitudinal dimension. The
flexible conductive strip may comprise a conductive wire comprising
a plurality of bends spaced across the length of the flexible
conductive strip. At least some of the bends may be configured to
allow the flexible conductive strip to be compressed or extended
along the longitudinal direction such that the density of the
conductive wire is increased or decreased along at least a portion
of the length of the flexible conductive strip. Making the
measurement may comprise transmitting a radio wave toward the
flexible conductive strip, receiving a radio wave transmitted from
the direction of the flexible conductive strip, and measuring the
resonant frequency of the flexible conductive strip. The resonant
frequency may be dependent upon the degree of compression
experienced by the flexible conductive strip.
[0025] In some embodiments, a system for assessing a degree of
wound closure of a wound comprising a wound filler and a conductive
element according to one or more of the features described in the
following description is disclosed.
[0026] In some embodiments, a method for assessing a degree of
wound closure of a wound comprising a wound filler and a conductive
element according to one or more of the features described in the
following description is disclosed.
[0027] Certain embodiments disclosed herein may provide for quick,
convenient, and accurate assessment of conformational changes in a
medical device and/or of the degree of wound closure. The
embodiments described herein may be used without requiring visual
assessment of the wound, wound filler, or other medical device and
thus may be especially useful in which visual inspection of the
medical device or wound is obstructed or impeded, such as by the
application of dressings. The embodiments may allow accurate
measurement of wound closure at various locations in the wound.
Measurements of wound closure may be correlated to physical
dimensions and/or relative amounts and may provide useful
information to the clinician, such as when to swap out a wound
filler device. Measurements may advantageously be made without
removing dressing or bandages from a wound and without placing a
detection device in direct contact with the body.
[0028] Further features and advantages of at least some of the
embodiments of the present disclosure, as well as the structure and
operation of various embodiments of the present disclosure, are
described in detail below with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates an example of a wound-filling matrix
according to some embodiments.
[0030] FIG. 2 illustrates the collapse of a wound-filling matrix
according to some embodiments.
[0031] FIG. 3 illustrates a wound filling matrix covered by foam
layers according to some embodiments.
[0032] FIGS. 4A-4K schematically illustrate various examples of
conductive elements for assessing dimensional changes in a medical
device according to some embodiments.
[0033] FIGS. 5A-5B schematically illustrate fixed density
conductive elements according to some embodiments. FIG. 5A
schematically illustrates the positioning of discrete fixed density
conductive elements on a wound-filling matrix. FIG. 5B
schematically illustrates the compression of a conductive strip
comprising flexible portions and non-flexible portions.
[0034] FIG. 6 schematically illustrates an example of a detection
device comprising a capacitive plate according to some
embodiments.
[0035] FIGS. 7A-7D schematically illustrate changes in density of
conductive elements positioned within a detection area of the
detection device according to some embodiments.
[0036] FIG. 8 illustrates a negative pressure treatment system
applied to a wound filler inserted into a wound according to some
embodiments.
DETAILED DESCRIPTION
[0037] In some embodiments, systems disclosed herein can comprise a
medical device configured for implantation into a human or animal
body and/or for attachment to a human or animal body and a
detection device for monitoring the configuration, arrangement,
and/or positioning of the medical device. The medical device may be
a wound filler, such as a wound-filling matrix, or other type of
wound dressing. In some implementations, the detection device may
be used to monitor the rate of wound closure and/or to determine a
metric of wound closure by analyzing the configuration of the wound
filler at a single point in time and/or by comparing readings from
multiple time points across a period of time. The medical device
may be made of a conductive material or made with a conductive
filler, may comprise a flexible conductive element, and/or may
comprise an arrangement of discrete conductive elements positioned
throughout the medical device, herein referred to collectively as
conductive elements. The medical device can be configured such that
the configuration, arrangement, and/or positioning of the medical
device may modulate the density of the conductive elements, such as
the local surface density, at one or more areas across a surface
area of the medical device. In some embodiments, the detection
device can be configured to assess the configuration, arrangement,
and/or positioning of the medical device in or on the body by
measuring the dielectric constant (relative permittivity) at the
one or more areas of the medical device where the density of
conductive elements is able to be modulated. In some embodiments,
the dielectric constant may by measured by measuring the change in
capacitance of a capacitive plate of the detection device. In some
embodiments, the detection device can be configured to assess the
configuration, arrangement, and/or positioning of the medical
device in or on the body by measuring the resonant frequency of a
flexible conductive element.
[0038] As used in this section or elsewhere in this specification,
the term "horizontal," when referring to a wound, indicates a
direction or plane generally parallel to the skin surrounding the
wound. The term "vertical," when referring to a wound, generally
refers to a direction extending perpendicular to the horizontal
plane. The term "longitudinal," when referring to a wound,
generally refers to a direction in the horizontal plane taken in a
direction along which the wound is longest. The term "lateral,"
when referring to a wound, generally refers to a direction in the
horizontal plane perpendicular to the longitudinal direction. The
terms "horizontal," "vertical," "longitudinal," and "lateral" may
also be used to describe the stabilizing structures and wound
closure devices described throughout this specification. When
describing these structures or devices, these terms should not be
construed to require that the structures or devices necessarily be
placed into a wound in a certain orientation, though in certain
embodiments, it may be preferable to do so.
[0039] Medical Devices Experiencing Measurable Dimensional
Changes
[0040] In some embodiments, the medical device may be a wound
filler. The wound filler may be a compressible/compactable device
or material configured for insertion into a wound (for example,
between the open edges of the wound). The wound filler may be
configured to stabilize the wound during wound closure/healing (and
may be referred to as a stabilizing structure) and may promote or
enhance wound healing (for example, by modulating the rate of wound
closure). In some embodiments, the wound filler may be a
compressible matrix. The matrix may comprise flexible and/or
articulable joints or hinges which allow the reorientation of the
matrix to progressively accommodate the decreasing area of the
wound as the wound closes. The wound filler may be configured for
use with negative pressure to promote wound closure.
[0041] FIG. 1 illustrates an example of a wound-filling matrix 100
comprising a plurality of elongate strips 106 arranged in parallel
or semi-parallel, whose longitudinal length can be aligned with the
longitudinal axis of a wound. In embodiments, the elongate strips
106 may also be arranged in a non-parallel fashion. The various
cells 104 within this wound-filling matrix 100 may have a variety
of shapes and sizes. The length and shape of the elongate strips
106, intervening members 110, and cells 104 may be designed so as
to facilitate greater closure of the wound-filling matrix 100. In
certain embodiments, the junctions 109 between the elongate strips
106 and intervening members 110 may be thinned to better facilitate
rotation and closure of the wound-filling matrix 100. In some
embodiments, the wound-filling matrix 100 is tearable and/or
frangible, such that the structure may be shaped into the shape of
a wound. Tears may be completed at the intersections between
intervening members 110 and elongate strips 106 or at any suitable
location along the elongate strip 106 or intervening member 110.
All wound-filling matrices 100 described herein may be fashioned to
accommodate any size of wound.
[0042] In certain embodiments, the wound-filling matrix 100 can
collapse in any manner described in this section or elsewhere in
this specification with or without the application of negative
pressure. For example, the wound-filling matrix 100 may collapse
significantly more in one plane than in another plane upon
application of negative pressure. In some embodiments, the
wound-filling matrix 100 is configured to collapse more in a
horizontal plane parallel to the length and width of the
stabilizing structure than in a vertical plane perpendicular to the
horizontal plane. In embodiments, particular rows may collapse in a
first direction, while another row may collapse in the same or an
opposing direction. In certain embodiments, the wound-filling
matrix 100 may collapse along the width of the matrix while
remaining relatively rigid along the length of the matrix and in
the vertical direction.
[0043] The wound-filling matrix 100 may be comprised of any
materials described in this section or elsewhere in this
specification, including: flexible plastics such as silicone,
polyurethane, rigid plastics such as polyvinyl chloride, semi-rigid
plastics, semi-flexible plastics, biocompatible materials,
composite materials, metals, and foam. In certain embodiments, the
stabilizing structure may comprise a radio opaque material, to more
readily allow a clinician to find pieces of the stabilizing
structure within the wound.
[0044] Returning to FIG. 1, wound-filling matrix 100 may have an
outer perimeter that defines an at least partially elliptical
shape. As described above, wound-filling matrix 100 may comprise a
plurality of cells 104 provided side-by-side, each cell 104 defined
by one or more walls, each cell 104 having a top end and a bottom
end with an opening extending through the top and bottom ends. As
with the other stabilizing structures described herein this section
and elsewhere in the specification, the wound-filling matrix 100
can be configured to collapse by collapsing one or more cells 104.
In some embodiments, the cells 104 are all of the same approximate
shape and size; however, in certain embodiments, the cells 104 are
of different shapes and sizes. In some embodiments, the
wound-filling matrix 100 as described herein this section or
elsewhere in the specification may be domed, such that the central
portion of the wound-filling matrix 100 structure bulges upward.
For example, a lower portion of the wound-filling matrix 100 may be
concave, while an upper portion of the wound-filling matrix 100 is
convex.
[0045] The elongate strips 106 may be made from one single
material, such as those described elsewhere in the specification,
or the elongate strips may be made from multiple materials. For
example, elongate strips 106 may comprise sections of more rigid
material and sections of more flexible material. The elongate
strips 106 may be curved along their length so as to facilitate the
curved outer perimeter of the wound-filling matrix 100. The
elongate strips 106 may be curved along their lengths outward away
from a center of the wound-filling matrix 100. The arch of the
curves of the elongate strips 106 may vary considerably, with some
strips 106 being highly curved while other are minimally curved or
even straight.
[0046] Similarly, the wound-filling matrix 100 can further comprise
a plurality of intervening members 110 connected to the elongate
strips 106. The intervening members 110 may all be of a similar
shape and size or they may be of a variety of shapes and sizes. The
intervening members 110 may be constructed from any material
disclosed herein this section or elsewhere in the specification.
Further, the intervening members 110 may be constructed from
multiple materials.
[0047] Advantageously, the elliptical shape of the wound-filling
matrix 100 may allow the structure to better accommodate the shape
of the wound. Most wounds are in shapes that are rounded, thus, an
elliptically shaped wound-filling matrix 100 may better fit into a
wound.
[0048] In embodiments, the outer perimeter 102 may have a reduced
edge 112 so as to facilitate collapse of the stabilizing structure.
By removing mass of the stabilizing structure at a reduced edge
112, the stabilizing structure can collapse more freely at the
reduced edge 112, thus allowing for a better fit within the wound.
Further, by reduced the mass at reduced edge 112, there may be less
pinching of the surrounding tissue during and after collapse of the
stabilizing structure 100.
[0049] The wound-filling matrix 100 and all wound fillers and wound
closure devices described in this section or elsewhere in this
specification can collapse on a variety of timescales in a dynamic
fashion. In certain embodiments, the majority of the collapse may
occur within the first few minutes upon application of negative
pressure. However, after the initial collapse, the wound-filling
matrix 100 or wound closure device may continue to collapse at a
much slower rate, thereby applying increasing longitudinal tension
over a long period of time and drawing the edges of the wound
closer together. By slowly drawing the wound edges closer together
over time, the wound-filling matrix 100 or wound closure device
allows the surrounding healing tissue to remodel synergistically
with the closure of the device or wound-filling matrix 100. Slow,
dynamic wound closure may allow the surrounding tissue to heal at
an accelerated rate, because the collapsing structure or device
slowly brings the edges of the wound closer together without
stressing the newly formed or weakened tissue too quickly.
[0050] In some embodiments, the wound-filling matrices 100
described in this section or elsewhere in this specification can be
placed into a wound for a period of time and then removed or
replaced with another wound-filling matrix 100. For example, a
wound-filling matrix 100 could be inserted into a wound for a
period of time, promoting closure of the wound by drawing the edges
closer together. After a period of time has passed, the
wound-filling matrix 100 can be replaced by a wound-filling matrix
100 of a different size or collapsibility, for example, a
wound-filling matrix 100 of a smaller size or decreased density.
This process could be repeated over and over, thereby continuously
drawing the edges of the wound together over time and allowing for
continuing repair and remodeling of the surrounding tissue. In
certain embodiments, the wound-filling matrix 100 is configured to
remain in the wound for less than about 1 hour, at least about 1
hour, at least about 2 hours, at least about 4 hours, at least
about 6 hours, at least about 8 hours, at least about 12 hours, at
least about 24 hours, at least about 2 days, at least about 4 days,
at least about 6 days, at least about 1 week, at least about 2
weeks, at least about 3 weeks, or more than about 3 weeks.
[0051] In certain embodiments, up to 90% of the collapse of the
wound-filling matrix 100 or wound closure device may occur within
the first few minutes upon application of negative pressure, while
the remaining 10% of the collapse may occur slowly over a period of
many minutes, hours, days, weeks, or months. In some embodiments,
up to about 80% of the collapse, up to about 70%, up to about 60%,
up to about 50%, up to about 40%, up to about 30%, up to about 20%,
up to about 10%, or about 0% of the collapse will occur immediately
within the first few minutes upon application of negative pressure
while the remainder of the collapse occurs at a much slower rate
such as over the course of many minutes, hours, days weeks, or
months. In certain embodiments, the wound-filling matrix 100 can
collapse at a variable rate. In some embodiments, the entirety of
the collapse occurs at a slowed rate, while in some embodiments the
entirety of the collapse occurs almost immediately within the first
few minutes. In further embodiments, the collapse can occur at any
rate and the rate can vary over time. In certain embodiments, the
rate of collapse can be altered in a variable fashion by adding
and/or removing portions of the structure or by controlling the
application of negative pressure and/or irrigant fluid.
[0052] FIG. 2 illustrates various configurations of collapse of a
half-portion of a wound-filling matrix. Each collapsible cell 130
has four sides, and each intersection between an intervening
member(s) and/or elongated strip(s) may be modeled via pin-joints
132. Further, the entirety of the wound-filling matrix may be
modeled inside of an oval wound model 136. As depicted in FIG. 2,
the wound-filling matrix may be modeled to collapse from an open
state 138 to a semi-collapsed state 140, to a fully collapsed state
142. In some clinical scenarios, maximum closure down to a
completely flattened wound-filling matrix may be desirable to
maximize wound closure by drawing the edges of the wound as close
together as possible.
[0053] The wound-filling matrices 100 and/or wound fillers and/or
wound closure devices described in this section or elsewhere in
this specification may be used in conjunction with methods or
systems for the closure of a wound. In some embodiments of methods
of use for closure of a wound, one or more of the wound-filling
matrices 100 or wound closure devices of any of the embodiments
described in this section or elsewhere in this specification is
placed into a wound. In some embodiments, an organ protection layer
may be provided in the wound before placement of the wound-filling
matrix 100. In certain embodiments, foam or other porous material
may be placed in the wound along with the wound-filling matrix 100
or wound closure device, either below, above, or surrounding the
wound-filling matrix 100 or wound closure device. Foam or other
porous material may also surround the perimeter of the
wound-filling matrix 100 or wound closure device. The wound-filling
matrix 100 or wound closure device may be configured to collapse in
any manner as described in this section or elsewhere in this
specification, for example, by having a particular size and shape,
or by comprising a certain volume of foam or other porous material
within the cells of the structure. The wound-filling matrix 100 or
wound closure device may further be altered in any manner described
in this section or elsewhere in this specification so as to better
accommodate the shape of the wound. After placement in the wound,
the wound-filling matrix 100 or wound closure device can be sealed
by a fluid-tight drape. The fluid-tight drape can comprise a port
configured for the application of negative pressure. A source of
negative pressure may then be connected to the port and negative
pressure may be applied to the wound. The wound-filling matrix 100
or wound closure device may be replaced over time by wound-filling
matrices 100 or wound closure devices of various shapes and sizes
as desired to best promote wound healing.
[0054] FIG. 3 illustrates an example of a wound-filling matrix 100
covered on its top and bottom surfaces by foam layers 300. Foam
layers may be positioned on the top and/or bottom surface of wound
fillers. The foam layers may help to distribute negative pressure
applied from an external negative pressure pump. The foam layers
300 may be placed into the wound, over the wound, under the wound
or a combination thereof. The foam layers 300 may be compressible
such that they are compressed along with the wound-filling matrix
100 as the wound closes. The foam layers 300 described herein may
include any type of foam described herein this section or elsewhere
in the specification. Possible foams may include open-celled and/or
reticulated foams made from a polymer. Suitable foams include foams
composed of, for example, polyurethane, silicone, hydrophobic
materials, hydrophilic materials, open-celled materials,
close-celled materials, mixed open and close-celled materials,
reticulated materials, polyester, silicone, and/or polyvinyl
alcohol. In embodiments, the foam layers 300 described herein may
include materials that change their properties over time. For
example, a particular foam may be rigid initially but become more
flexible when wet and/or lose rigidity over time due to degradation
of the material. In embodiments of the foam layers, the layers of
foam may comprise any type of suitable foam material described
herein this section or elsewhere in the specification. For example,
the foam may comprise "black foam" such as polyurethane and/or
"white foam" comprising polyvinyl alcohol (PVA). In embodiments
involving PVA foam, thinner foam layers may be needed as compared
to other types of foam, because PVA foam is often more resilient
and dense than other types of foam. Further, once PVA foam becomes
wet it may also aid with lateral slip. In some embodiments, the
foam layers may be combined with other fillers such as gauze, or
other mesh/net products such as those on Fry and Kossel. In some
embodiments, the foam layer or collective foam layers may be
considered the medical device.
[0055] In some embodiments, the medical device may be a dressing,
drape, wrap, bandage, splint, cast or other support attached to a
joint of the body (for example, the elbow, knee, etc.). The support
may be at least somewhat flexible. The support may be configured to
help stabilize operative equipment attached to the joint. For
example, the support may be a dressing surrounding a negative
pressure pump operatively connected to an open wound on the joint.
The support may be configured to at least partially stabilize the
joint. For example, the medical device may be a splint. The medical
device may be compressed (for example, squished or forced to fold
up on itself) or stretched upon flexion or extension of the joint.
In some embodiments, the medical device may be at least somewhat
elastic. The systems, devices, and methods disclosed herein may be
used to assess the degree of flexion or extension of a joint to
which the medical device is attached or in which it is implanted
either at a point in time or over a duration of time. For instance,
bending of the joint may cause compression or extension of the
medical device along the plane of movement. In some
implementations, the detection device may be applied to the joint
as a sensor. The sensor may be configured to record flexion and/or
tension over time and can be used, for example, to assess patient
compliance. The sensor may be useful for monitoring either whether
the patient is compliant with a healing regimen which requires
little or no movement of the joint or whether the patient is
compliant with a therapeutic movement or exercise regimen which
should involve periodic movement of the joint. In some
implementations, the detection device may be a non-contact device
(for example, a hand-held instrument). The detection device may be
used to measure the angle of a joint. Such a measurement may be
especially useful if the precise angle of the joint is difficult to
visually perceive and/or measure, such as if the joint is
sufficiently concealed and/or covered by the medical device and/or
other attachments. Precise angles of the joint may be determinable
such as through calibration methods described elsewhere herein.
Incorporation of Conductive Elements for Monitoring Dimensional
Changes
[0056] In some embodiments, the various medical devices described
herein may be defined to have a surface area extending along a
horizontal plane. The surface area of the medical device may extend
substantially parallel to a surface of the body. The medical device
may be positioned on top of a surface of the body, within the
surface of the body, underneath the surface of the body, or
combinations thereof. The surface area may be relatively flat or
may be curved to match the contour of the surface of a body part
(for example, an elbow, knee, hip, etc.). The medical devices may
be defined to have a thickness extending substantially
perpendicular to the surface area of the medical device. The
surface area of the medical device may be considered to be on top
of the medical device, below the medical device, somewhere between
the top surface and the bottom surface, or extending throughout the
thickness of the medical device. The systems, devices, and methods
disclosed herein may be configured to monitor physical changes in
the surface area of the medical device, including, but not limited
to, compaction, extension, rearrangement, reconfiguration, and/or
bending of the surface area of the medical device. In some
embodiments, the systems, device, and methods disclosed herein may
alternatively or additionally monitor physical or structural
changes in the vertical direction (for example, changes in the
density of the thickness of the medical device).
[0057] Physical changes in the surface area of the medical device
may be obscured from the view of a clinician. For instance, a wound
may be covered with foam, gauze, dressing, or other materials which
obscure the interior and/or the edges of the wound and/or the wound
filler. Therefore, it may be impossible or impracticable for the
clinician or other observer to visually detect the changes in the
surface area of the medical device and/or corresponding changes in
the size of a wound. For instance, a clinician may not be able to
discern the amount of wound closure that has occurred over time
using a wound filler, without removing layers of material from the
wound. Even then, visual assessment of the wound may not provide
sufficient quantitative measurement of the changes in wound
dimensions. Measurement of the wound using standard measurement
tools (for example, rulers, measuring tape, calipers, etc.) may
require prolonged exposure of the wound and/or unwanted contacted
with the wound.
[0058] FIGS. 4A-4K illustrate various examples of conductive
elements for use with the medical device as applied to a wound
filler medical device 400. In some examples, the wound filler 400
may be a wound-filling matrix 401. In various implementations, the
conductive elements may comprise a metal (for example, silver,
gold, carbon steel, etc.). The incorporation of the conductive
element in or on the medical device may alter (for example,
increase) the dielectric constant of the medical device over a
localized area where the conductive element is positioned. In some
implementations, the dielectric constant may be raised such that
the background level, regardless the degree of compression, is
elevated above that which would be altered by the presence of wound
fluid. In some implementations, the depth of detection may be
limited by the detection device to focus on the surface of the
medical device, such that, for example, the effect of wound fluid
found deeper in the wound is minimized. In some embodiments, the
conductive element may be a conductive filler 402 (for example,
metal particulate, or powder) which is incorporated directly into
the medical device. For instance, the medical device may comprise a
polymer (for example, silicone) or foam and the conductive filler
402 may be embedded in the polymer during fabrication. In some
implementations, the conductive filler 402 may be uniformly
distributed throughout the medical device, as schematically
illustrated in the wound filler 400 of FIG. 4A, such that the solid
polymer portions of the medical device comprise a relatively
homogenous dielectric constant. In some implementations, the
conductive filler 402 may be localized to certain areas (for
example, flexible joints or articulable components of the medical
device), as schematically illustrated in the vertices 403 of the
wound-filling matrix 401 of FIG. 4B, such that those areas may be
used as conductive markers. The detection device may be used to
detect the relative changes in density of the conductive material
that occur by rearrangement of the physical structure (for example,
the polymer matrix) and/or by bringing the conductive markers
closer together or further apart.
[0059] In some embodiments, the conductive elements may be discrete
conductive elements 404 positioned strategically throughout the
medical device to serve as markers used to track localized density
of the medical device. For example, the medical device may comprise
conductive inserts or clips. FIG. 4C schematically illustrates an
example of an insert 406. The inserts may comprise a long slender
body (for example, a cylindrical shaft). The inserts 406 may be
configured, for example, as pins or tacks that are inserted into
the medical device. FIG. 4D schematically illustrates an example of
a clip 408 attached to a wound-filling matrix 401. The clips 408
may be configured, for example, to slide over, clamp to, or
otherwise be secured to the elongate strips or intervening members
of a wound-filling matrix 401, as described elsewhere herein. The
clips 408 may have an elastic bias which secures them to elongate
members of the medical device, such as the elongate strips of a
wound-filling matrix 401. In some implementations, the length of
the discrete conductive element 404 may be used to modulate the
relative change in the localized dielectric constant. For instance,
longer conductive elements may more measurably alter (for example,
increase) the localized dielectric constant of the medical device
than shorter conductive elements. Similarly, the surface area of
the conductive element 404 may be used to modulate the relative
change in the localized dielectric constant. Discrete conductive
elements 404 with larger surface areas may more measurably alter
the localized dielectric constant of the medical device than
discrete conductive elements with smaller surface areas. The
discrete conductive elements 404 may be configured with heads, such
as heads 407, 409 illustrated in FIGS. 4C and 4D, respectively,
that may sit above the top surface of the medical device and act to
increase the surface area of the discrete conductive element 404
within a detection area of the detection device. The heads of the
discrete conductive elements 404 may be relatively flat to maintain
a low profile with the medical device. These discrete conductive
elements 404 may be spread across a surface area of the medical
device and may extend a depth into the thickness of the medical
device. In embodiments comprising a bulk wound filler material, the
discrete conductive elements may be distributed substantially
uniformly across the surface area of the wound filler or
substantially uniformly across localized areas of the wound filler
expected to undergo dynamic changes. In embodiments, comprising a
wound-filling matrix such as matrix 100, the discrete conductive
elements 404 may be positioned at or near one or more of the
vertices of the matrix 100, as shown in FIG. 4E. In some
embodiments, a discrete conductive element 404 may be positioned at
each vertex 109. In some implementations, the discrete conductive
elements 404 may be incorporated into the medical device during
fabrication of medical device. In some implementations, the
discrete conductive elements 404 may be incorporated after the
fabrication of the device, either before or after implantation or
attachment to the body.
[0060] In some embodiments, the medical device may be fabricated
with conductive components configured to serve as markers for
density changes. For example, as illustrated in FIG. 4F, the
medical device may be a wound-filling matrix 410 fabricated with
conductive (for example, metal) joints or hinges 411 that join
together certain components of the medical device (for example,
elongate strips 412 and intervening members 413). These conductive
joints 411 may be brought closer together or further apart during
use of the medical device, such as when a wound-filling matrix 410
is folded, rotated, or articulated around the joints 411 that form
the vertices of the matrix.
[0061] In some embodiments, the conductive element may be one or
more conductive wires 414 coupled to the top surface and/or the
bottom surface of the medical device or inserted through the
medical device parallel to the horizontal plane. FIG. 4G
schematically illustrates an example of conductive wires 414
coupled to a wound filler 400. The conductive wires 414 may
comprise a length extending from a first end of the conductive wire
414 to a second end of the conductive wire 414. In some
embodiments, multiple conductive wires 414 may be positioned
relatively parallel or semi-parallel to one another. The conductive
wires 414 may be relatively straight. The conductive wires 414 may
be curved to conform to the natural contours of the surface of the
body. The conductive wires 414 may be spaced across a first
direction in which the medical device is expected to experience a
measurable change in dimensions (for example, the lateral dimension
of a wound filler). The length of the conductive wires 414 may be
aligned along a second direction in which the medical device is
expected to experience little or no change in dimension (for
example, the longitudinal direction of a wound filler). The second
direction may be perpendicular to the first direction. The
conductive wires 414 may be brought closer together or further
apart as the medical device is compacted or extended along the
first direction. The conductive wires 414 may be especially
suitable for medical devises which experience anisotropic
dimensional changes. For instance, the conductive wires 414 may be
applied to a wound filler which collapses primarily in one
direction to bring opposite edges of the wound closer together.
These edges may then be sewed together. In embodiments where the
wound filler is an articulable matrix, the conductive wires may be
aligned to elongate strips of the matrix. The conductive wires 414
may be coupled by any suitable means. For example, the conductive
wires 414 may be glued, stapled, or sewn to the top or bottom
surface of the wound filler 400 or embedded directly in the wound
filler 400. In embodiments comprising a wound-filling matrix, the
conductive wire 414 may be coupled to one or more of the lengths of
a longitudinal or transverse member (for example, the elongate
strips 106 of wound-filling matrix 100).
[0062] In some embodiments, conductive wires 414 may be configured
to collapse or expand along a length of the conductive wire 414
upon compressing or extending, respectively, the medical device in
that direction. For instance, the conductive wires 414 may comprise
bends 415 spaced apart along their length and positioned in a
single plane. The bends 415 may be periodic. For example, the bends
415 may shape the conductive wire 414 in a sinusoidal or serpentine
pattern having smooth, rounded bends 415, as shown in FIGS. 4H and
41, respectively, and/or the bends 415 may shape the wire in a
zig-zag pattern having sharp, triangular bends, as shown in FIG.
4J. The bends 415 may be configured to expand (an increase in the
angle of the bend) upon extension and to collapse (a decrease in
the angle of the bend) upon compression. The bends 415 may shape
the conductive wire 414 into a flexible conductive element such as
a flexible conductive strip 416 comprising a length along a longer
dimension (the longitudinal axis of the conductive strip 416) and a
width along a shorter dimension (the lateral axis of the conductive
strip 416), perpendicular to the longer direction. In some
embodiments, the bends 415 may be uniformly spaced such that the
conductive strip 416 is a constant width along its length. In some
embodiments, the bends 415 may be spaced such that the conductive
strip 416 has a varying width along its length.
[0063] FIG. 4K schematically illustrates examples of the
positioning of various flexible conductive strips 416 on a
wound-filling matrix 401. The medical device may incorporate one or
more conductive strips 416. In embodiments comprising multiple
conductive strips 416, the strips 416 may be the same length or
different lengths, the same pattern or different pattern, have the
same frequency and/or pitch of bends 425 or different frequencies
and/or pitches of bends 425, etc. In embodiments comprising a wound
filling matrix, such as matrix 401 shown in FIG. 4K, the conductive
strips 416 may be attached, for example, at different points along
the longitudinal axis of the matrix 401 to the same elongate strip
405 or to different elongate strips 405. The conductive strip 416
may be configured to impart negligible resistance to compression
and/or extension of the medical device along the longitudinal
direction of the conductive strip 416. The amount of resistance may
increase for larger degrees of compression and/or extension. The
resistance of the conductive strip 416 to compression and/or
extension may be sufficiently low, even at more extreme degrees of
compression and/or extension, such that, for instance, the
conductive strip 416 does not impede the reconfiguration of the
medical device. For example, the conductive strip 416 may be
configured to provide a low enough resistance to compression such
that it does not impede or alter the rate of wound closure when
coupled to a wound filler. The thickness or gauge of the conductive
wire 414 may be relatively thin to facilitate compression and/or
extension of the bends 415 along the length of the conductive strip
416. The conductive wire 414 may be fabricated of a material that
is relatively flexible (easy to bend) to minimize resistance to
compression and/or extension.
[0064] The flexible conductive strip 416 may be particularly
suitable for assessing anisotropic changes in dimensions of medical
devices, particularly changes in a single dimension. The
compression or extension of the conductive strip 416 along its
longitudinal axis increases or decreases, respectively, the density
of the conductive material along the longitudinal direction between
the first end and second end of the conductive wire 414. For
instance, the compression of a conductive strip 416 may amplify the
relative change in the density of conductive material for a given
compressive strain relative to bringing together spaced, discrete
conductive elements 404. The flexible conductive strip 416 may also
provide a relatively uniform measure of density along the length of
the conductive strip 416 relative to spaced, discrete conductive
elements 404. The spacing of the bends 415 and/or the sharpness of
the bends 415 may be used to modulate the relative changes in
density upon given amounts of compression and/or extension. The
bend spacing and bend angle parameters may be used to optimize the
range of relative changes in the density of conductive material.
The optimization may depend on the size of the detection area of
the detection device, described elsewhere herein. The periodic
bends 415 of the conductive strip 416 may bridge gaps in the
medical device (for example, gaps in a wound-filling matrix 401)
such that density changes can be monitored whether or not the
detection area of the detection device is large enough to span the
gaps of the medical device. The conductive strips 416 may be
strategically coupled to the medical device to target localized
areas where dimensional changes are expected to occur. The
conductive strips 416 may be strategically positioned such that the
longitudinal axis of the conductive strip 416 is aligned with a
dimension of the medical device expected to experience dimensional
change (for example, anisotropic change). In some embodiments, the
conductive strip 416 may be slightly elevated above the top surface
of the medical device to avoid interfering with the compression of
the device (for example, becoming pinched between collapsing
members of a wound-filling matrix).
[0065] The flexible conductive strip 416 may be coupled to a
non-conductive element. For example, the conductive strip 416 may
be joined to a fabric. The fabric may be elastic to allow for the
compression or extension of the conductive strip 416. In some
implementations, the conductive strip 416 may be sewn or otherwise
embedded into a non-conductive fabric strip (for example, between a
top layer of fabric and a bottom layer of fabric). The
non-conductive fabric strip may be used to readily couple the
conductive strip to the surface of the medical device, for
instance, by stapling, gluing, pinning, etc. The non-conductive
fabric strip may be coupled at two ends of the fabric strip to the
medical device or it may be coupled at multiple points along the
length of the fabric strip. Coupling the conductive strip 416 to
the medical device (for example, via coupling of the non-conductive
strip) may effectively divide the conductive strip 416 into
portions which may experience different degrees of
compression/extension. Measuring the differences in density between
the portions may indicate relative degrees of difference in the
compression or expansion of the medical device along the
longitudinal axis of the conductive strip 416.
[0066] Any of the conductive elements disclosed herein, including
the flexible conductive strip 416, may be coupled to a wound
filler, such as a wound-filling matrix, by embedding the conductive
element into the wound-filler or bonding the conductive element to
the surface of the wound filler. For instance, the conductive
elements may be embedded in or bonded to the elongate strips and/or
intervening members of a wound-filling matrix. For example, the
conductive elements may be printed, thermally printed, thermally
bonded or woven into the wound filler. The conductive elements may
be inset-cast into the molding of the wound filler. The conductive
elements may be bonded by local thermal or ultrasonic/laser welding
of the materials, such as where the wound filler comprises a
thermoplastic. In some implementations, the solid portions of the
wound filler may be configured with sufficient internal spaces or
cavities to allow flexing or bending of conductive elements such as
flexible conductive strips. In some implementations, the wound
filler may be configured with sufficient elasticity to extend or
compress along with a flexible conductive element. In some
implementations, flexible conductive elements, such as flexible
conductive strips 416, may be coupled to a wound-filling matrix
such that the bends are positioned at vertices of the matrix and
the zig-zag pattern of a flexible conductive strip 416 follows the
zig-zag pattern of the matrix.
[0067] In some implementations, conductive elements of a fixed
spatial density may be incorporated into the medical device,
referred to herein as fixed density conductive elements 518. The
fixed density conductive elements 518 may be used as a reference
and/or baseline signal for calibrating the detection device. The
fixed density conductive elements 518 can be used to minimized the
effects of wound fluid on the detection device. The fixed density
conductive elements 518 may be useful in distinguishing detectable
changes (for example, changes in dielectric constant) resulting
from dimensional changes in the medical device from changes
resulting from the presence of wound fluid. The fixed density
conductive elements may be useful in assisting a user in holding,
placing, or positioning the detection device a suitable distance
from the medical device. For example, if the detection device is
positioned too far from the fixed density conductive elements 518,
the detection device may effectively give a "no signal" reading.
The fixed density conductive elements 518 may be the same as the
conductive elements described elsewhere herein (for example,
discrete conductive elements 404), but may be positioned in an area
of the medical device that is known or expected not to undergo any
dimensional changes or only to undergo negligible dimensional
changes. For example, the fixed density conductive elements 518 may
comprise a plurality of discrete conductive elements positioned
along vertices of a wound-filling matrix. The fixed density
conductive elements 518 may be positioned at portions of a wound
filler expected to experience relatively little compaction. For
instance, the fixed density conductive elements 518 may be
positioned along an edge and/or at a corner of a wound filler. The
fixed density conductive elements 518 may be positioned along a
midline of the wound filler towards which the device is configured
to collapse. FIG. 5A schematically illustrates the positioning of
fixed density conductive elements 518 at several vertices 503
located at the corner of a wound-filling matrix 501. In some
implementations, a single fixed density conductive element 518 may
be used for calibration. In some implementations, a calibration may
be performed on an area having no conductive elements positioned
therein.
[0068] In some embodiments, the fixed density conductive element
518 may be a non-flexible (substantially rigid) conductive strip.
The non-flexible conductive strip may be similar to the conductive
strips 416 described elsewhere herein, except the non-flexible
conductive strip or at least a portion of the length of the strip
may be non-flexible such that the bends in the conductive wire
neither collapse nor expand upon compression or extension of the
medical device. The non-flexible conductive strip or non-flexible
portion of the conductive strip may be made relatively rigid
through any suitable means. For instance, the non-flexible strip
may comprise a more rigid material than the flexible conductive
strips 416 and/or may be made of a thicker gauge wire. The
non-flexible conductive strip may be flanked on both ends by
flexible members which absorb the strain of compression and/or
expansion. For instance, the non-flexible conductive strip may be
flanked by elastic fabric on either side and/or by flexible
conductive strips 416, described elsewhere herein. The non-flexible
conductive strips may be coupled to the medical device along
lengths of the device expected to experience no or little
dimensional changes or may be coupled to the device along lengths
expected to be compressed or extended, particularly when the
non-flexible conductive strip is flanked by flexible members. In
some implementations, conductive strips 516 may comprise both
flexible portions 517 and non-flexible portions 519, as
schematically illustrated in FIG. 5B, showing the compression of a
conductive strip 516 comprising both flexible portions 517 and
non-flexible portions 519. For instance, there may be one or more
non-flexible portions 517 positioned along the length of a
conductive strip 516. In some implementations, the flexible
portions 517 may be used to measure density changes, which may be
correlated to wound closure, whereas the non-flexible portions 519
may be used for calibrating the detection device.
Detection of Dimensional Changes in the Medical Device
[0069] In some embodiments, the detection device may be configured
as a non-contact device. FIG. 6 schematically illustrates an
example of a detection device 600 positioned proximate to the
surface 602 of a medical device, such as a wound filler. The
detection device 600 may be configured as a scanning device, in
which the device performs a detection measurement over an effective
detection area 604. In some implementations, the device can be
scanned over an area larger than the detection area 604, such that
the detection area 604 is continually updated. The detection device
600 may be hand-held. The detection device 600 may comprise a
distal end 606 configured to scan the detection area 604. The
distal end 606 may comprise a relatively flat surface 607
configured to be placed over and proximate to the surface 602 of
the medical device for detection. The detection device 600 can
determine and provide indication of one or more dimensional
changes, such as compression of a wound filler. Indication can be
one or more of visual, audible, tactile, or the like.
[0070] In some embodiments, the detection device 600 may comprise
one or more capacitive plates 608 positioned at the distal end 606.
The one or more capacitive plates 608 may be oriented such that the
faces of the plates 608 are parallel to the relatively flat surface
607. In some embodiments, the one or more capacitive plates 608 may
be positioned just behind the flat surface 607 (for example, behind
a non-conductive casing forming the flat surface 607), as shown in
FIG. 6. In some embodiments, the one or more capacitive plates 608
may form the flat surface 607 or may be integral with the flat
surface 607, such that the plates 608 are exposed or partially
exposed. The capacitive plate 608 may be a capacitive element in a
form other than a flat plate. The shape of the capacitive plate 608
may be used as is known in the art to modulate the zone of
detection or detection volume. For instance, the shape may be used
to establish a detection zone that extends substantially straight
form the capacitive plate, a detection zone that extends as a cone
(for example, a 90 degree cone) from the capacitive plate, or an
omnidirectional detection zone (for example, a substantially
spherical detection zone). In some implementations, the range of
sensitivity may be modulated as is known in the art. The range of
sensitivity may be used to limit the depth of detection as
described elsewhere herein. For example, the range of sensitivity
may be less than about 5 mm, less than about 6 mm, less than about
10 mm, less than about 15 mm, less than about 18 mm, less than
about 20 mm, less than about 25 mm, less than about 30 mm, less
than about 50 mm, or greater than or equal to about 50 mm. The
detection device 600 may be configured to apply a voltage/current
to the one or more capacitive plates 608. The amount of charge
stored on a capacitive plate 608 may be modulated by the material
properties of a detection volume adjacent the capacitive plate 608.
The detection volume may be an indefinite volume, in which the
closer to the capacitive plate 608 a material is positioned the
larger its impact on the charge of the plate 608 (for example, a
spherical volume centered around the capacitive plate 608). The
dielectric constant of the detection volume, or an averaged
dielectric constant, can influence the amount of charge stored on
the one or more capacitive plates 608. The detection device 600 may
comprise circuitry similar to that found in an electronic stud
finder, such as that described in U.S. Pat. No. 4,099,118, titled
"Electronic Wall Stud Sensor", issued Jul. 4, 1978, which is hereby
incorporated by reference in its entirety. For instance, the
detection device 600 may use the variable charge stored on the one
or more capacitive plates 608 to modulate the time constant of a
multi-vibrator or other timing component. The modulated time
constant may be compared to a component with a fixed timing
constant to determine a difference in the charge (e.g., via a meter
M). The detection device 600 may output a voltage, current, or
other electronic parameter (a reading) that is correlated to the
charge on the one or more capacitive plates 608, affected by the
variable dielectric constant of the detection area 604.
[0071] In some embodiments, the detection device 600 may be
configured similar to that shown in FIG. 6 and as described
elsewhere herein, but may use a radio transmitter and receiver
alternatively to or in addition to capacitive plates for detection.
The detection device 600 may use electromagnetic waves (for
example, radio waves) in combination with a flexible conductive
element 416 to assess the configuration, arrangement, and/or
positioning of the medical device. The detection device 600 may
comprise a radio transmitter for transmitting radio waves. The
radio transmitter may transmit waves across a spectrum of
detectable frequencies. The transmitted frequency may change over
time. The radio transmitter may vary the frequency according to any
suitable pattern. For example, the radio transmitter may
continuously cycle between a minimum frequency and a maximum
frequency. The frequency may be modulated by conductive, inductive,
and/or capacitive circuit elements. The change in frequency over
time may follow a preset time scale and/or may be adjusted by the
user. In some implementations, the radio transmitter may transmit
multiple frequencies simultaneously. The radio transmitter can be
configured to direct the waves toward the medical device. The radio
transmitter may comprise an aerial/antenna. The detection device
600 may comprise a radio receiver configured to detect
electromagnetic waves. The radio receiver may be configured with
circuitry to determine the frequency of the detected waves. The
radio receiver may be configured to identify a wave from a
plurality of waves comprising a maximum amplitude. The radio
receiver may be configured to filter out electromagnetic noise. The
radio receiver may be configured to register frequencies of waves
above a threshold amplitude. In some implementations, the detection
device 600 may be configured to produce a voltage and/or current
measurement corresponding to the detected frequency value.
[0072] The flexible conductive element 416 may be used as a
radiofrequency (RF) resonator (such as, an untuned aerial). The
flexible conductive element 416 may receive and simultaneously
transmit the received electromagnetic wave. The flexible conductive
element 416 may experience a particular resonant frequency at which
it resonates and transmits the received wave at a detectably higher
amplitude than at other frequencies. The resonant frequency of the
flexible conductive element 416 may be affected by the overall
length, shape, and/or material properties of the flexible conductor
element 416. In some embodiments, the flexible conductive element
416 will resonate better where it acts as a full wave, half-wave,
quarter wave, or harmonic wave oscillator to an RF response.
Expansion or compression of a flexible conductive element 416, as
described elsewhere herein, may modulate the resonant frequency of
the flexible conductive element 416 (for example, the wavelength of
the resonant frequency may drop as a flexible conductive element
416, such as a zig-zag conductive element, is compressed). Altering
the length of the resonator in the direction of the RF source can
alter its resonant response. The detection device 600 may detect
the resonant frequency of the flexible conductive element 416 by
using the transmitter to transmit waves of various frequencies
across a spectrum and using the receiver to identify at which
frequency the flexible conductive element 416 resonates. The length
of the resonator can be determined from the adsorption and/or
transmission response of the resonator. The amount of compression
or expansion of the flexible conductive element 416 can be
determined according to one or more calibration techniques,
described elsewhere herein.
[0073] In some embodiments, the resonator may be fixed. For
example, a conductive element, such as the element 416, may be
configured not to be compressed or extended. A capacitive element
and/or inductive element may be coupled to the medical device.
Dimensional changes in the medical device may alter the spatial
positioning of the capacitive and/or inductive element relative to
the resonator. The spatial positioning may modulate the tuning of
the resonator so that the frequency at which it resonates depends
on dimensional changes in the medical device, such as the amount of
compression of a wound filler.
[0074] In some embodiments, the detection device 600 may be
configured similar to that shown in FIG. 6 and as described
elsewhere herein, but may generate a magnetic field. The magnetic
field can be a low-power fluctuating magnetic field. Changes due to
compression of the medical device, such as a wound filler, may
alter (for example, raise) the magnetic permeability or
permittivity within the detection area. For instance, changes in
the resonant frequency of a flexible conductive element, such as a
flexible conductive strip, may alter the magnetic permittivity of
the detection area. The magnetic permittivity within a detection
area may be detected using the magnetic field generated by the
detection device 600.
[0075] The strategic positioning of conductive elements across the
surface of the medical device can be used to effect changes in the
dielectric constant of the detection volume of the one or more
capacitive plates 608 of the detection device 600 upon compaction
or expansion of the surface area of the medical device. In some
embodiments, the strategic positioning of flexible conductive
elements 416 may be used to effect changes in the resonant
frequency detected by the detection device 600 upon compaction or
expansion of the surface area of the medical device. The medical
device may be configured to exhibit a changing dielectric constant
primarily across a surface area of the medical device, depending on
the device configuration at any point in time, and to maintain a
relatively steady dielectric constant across the thickness or depth
of the medical device. Therefore, the detection volume may be
effectively treated as a detection area 604 across which changes in
the dielectric constant are expected to occur. In certain
embodiments, changes across the thickness of the medical device may
alternatively or additionally be detected. The size of the
effective detection area 604 across which changes in the dielectric
constant and/or resonant frequency of the medical device can
effectively be measured may depend on the electronic parameters of
the detection device 600 (for example, the size of the capacitive
plate 608, the configuration or number of capacitive plates 608,
the voltage applied to the plate 608, the inclusion of amplifying
circuitry, the calibration of the detection device 600, etc.). The
compression or expansion of the medical device, or any other
changes in the dimensions of the surface area of the medical device
may result in an increase or decrease of the density of a single
flexible conductive element 416 or the density of a plurality of
discrete conductive elements 404 or conductive filler 402 within
localized areas of the medical device. Density changes of the
conductive elements within a detection area 604 of the detection
device 600 may be detected by an increase or decrease in the
localized dielectric constant which may modulate the amount of
charge stored on the one or more capacitive plates 608 and/or by an
increase or decrease in the resonant frequency detected by a radio
receiver.
[0076] FIGS. 7A-7D schematically illustrate changes in density of
conductive elements positioned within a detection area 700 of the
detection device. FIG. 7A shows the isotropic compression of a
medical device comprising discrete conductive elements 704. FIG. 7B
shows the anisotropic compression of a medical device comprising
discrete conductive elements 704. FIG. 7C shows the anisotropic
compression of a medical device comprising conductive wires 714.
FIG. 7D shows the anisotropic compression of a medical device
comprising conductive strips 716. During compression of the medical
device in each of these examples, the amount of conductive material
within the effective detection area 700 (the density of conductive
material) is increased, such that the effective dielectric constant
of the medical device within the detection area 700 may be
modulated (for example, increased by the higher density of
conductive metal). During expansion of the medical device, the
density of conductive material within the effective detection area
700 may be modulated in an opposite manner (for example,
decreased).
[0077] In some embodiments, the detection device may be
pre-calibrated. For instance, prior to clinical use the detection
device may be used to make a plurality of measurements on different
calibration standards. The calibration standards may comprise the
same conductive elements used in the medical device, positioned at
various arrangements that constitute various spatial densities of
the conductive material. The spatial densities may be indicative of
the range of spatial densities of the conductive elements expected
to be measured during clinical use of the medical device. The
calibration measurements may be correlated to distances between
conductive elements (for example, along a single direction or over
a two-dimensional area) or any other suitable measures that can
reflect spatial changes experienced by the medical device. In some
implementations, the calibration measurements can be used to create
a standard curve and/or a look-up table, from which spatial
measurements may be interpolated or extrapolated based on readings
from the detection device. In some implementations, a mathematical
expression can be defined relating the detection device readings to
spatial measurements, such as by solving an analytic equation using
calibration measurements to determine relevant parameters. In some
implementations, the calibration measurements may be performed on
the medical device comprising the actual conductive element to be
used prior to implantation or attachment of the medical device to
the body.
[0078] In some embodiments, the detection device may be entirely or
partially calibrated during clinical use. For example, the
clinician may scan an area of the medical device comprising a fixed
density conductive element, as described elsewhere herein. This
reading may be compared to one or more readings from areas
comprising non-fixed conductive elements. For instance, the fixed
density conductive element may provide a baseline reading. Readings
from other areas may be expressed relative to the baseline reading.
In this manner, relative compression and/or expansion of the device
may be tracked over time. The detection device may be configured to
read a calibration value and output a relative measurement or the
clinician may manually record the reference value and calculate the
variable density readings accordingly. In some implementations, the
fixed density conductive element may be configured at a density
approximate a final expected density. For instance, the density of
the fixed density conductive element positioned in or on a wound
filler may be indicative of the density that similar non-fixed
conductive elements are expected to achieve near full compression
or collapse of the wound filler (for example, when the wound is
near closing) or at a point where the wound filler is expected to
be swapped out. The variable readings of the conductive element may
then approach the baseline reading as the wound closing procedure
progresses. Using such methods, the detection device can be
configured to provide measurements of wound closure without
requiring pre-calibration or even storage of calibration values. In
some embodiments, the user may perform a relatively concurrent
calibration measurement using a calibration standard that is not
incorporated into the medical device. In some embodiments, the
relative difference in readings between the fixed density
conductive element and the conductive element may be correlated to
a change in spatial dimensions using a calibration curve, table, or
equation.
[0079] In some embodiments, the user may be able to calibrate the
detection device by "zeroing" a reading, in which the measured
value is effectively set to zero. Zeroing a reading may adjust the
detection range of the detection device to more effectively detect
and distinguish values within a range of interest (for example,
ranges corresponding to the different spatial densities of
conductive elements experienced by the medical device in clinical
use). The detection device may zero a reading, for example, by
using a potentiometer to adjust the voltage and/or current applied
to the one or more capacitive plates or to affect other components
of the circuitry. In some implementations, a detection area
comprising no conductive elements (for example, a portion of a
wound filler without any conduction elements) may be used to zero
the detection device. This calibration may be used in conjunction
with other calibration procedures described herein. In some
implementations, a detection area comprising a fixed density
conduction element may be used to zero the device.
[0080] In some embodiments, the system may include a processor
and/or memory. In some embodiments, the processor and/or memory are
internal components of the detection device. In some embodiments,
the detection device is operatively coupled to an external
processor and/or external memory, such as a computer, tablet, smart
phone, etc. The detection device may be wirelessly coupled (for
example, using WIFI, Bluetooth, etc.) to the external components.
The detection device may be coupled using a data cord (for example,
a USB cable). The detection device may be configured to store
calibration values or other calibration data.
[0081] The detection device may be configured to determine a metric
of spatial density, movement, reconfiguration, etc. For example,
the detection device may be configured to determine a metric of
wound closure (for example, a closure distance or a reduction in
area). The detection device may include a display for displaying
raw readings and/or determined metrics. The detection device may
include input features for a user to set operating parameters. In
some embodiments, the user may be able to select a calibration mode
such that the reading is used as a reference reading and/or a zero
reading, as described elsewhere herein. For instance, the detection
device may include a button the user presses when making a
calibration reading. In some embodiments, the detection device may
provide continually updated readings. For instance, the detection
device may be moved (for example, in a linear fashion) across a
detection path while refreshing the reading to correspond to the
changing detection area. The detection device may refresh according
to a predetermined time increment. During the time increment the
detection device may average the input from the detection device to
determine an output value. In some embodiments, the detection
device may include a capture button wherein the user can request
the detection device make a measurement at the moment the button is
pressed.
[0082] In some embodiments, the detection device may be configured
as a sensor to be attached to the body (for example, over the
medical device) for an indefinite period of time. The sensor may be
configured to simultaneously and/or sequentially scan one or more
detection areas, which may be strategically positioned over the
medical device. The sensor may be strapped, adhered (for example,
adhesive), or coupled to the body by any suitable means. For
example, the sensor may be configured in a patch or wrist-watch
type configuration. The sensor may be in contact with the medical
device or coupled such that there is a gap or space between the
sensor and the medical device.
Wound Treatment
[0083] In some embodiments, the medical device is a wound-closure
device, such as a wound filler (for example, a wound-filling
matrix), as described elsewhere herein. In some implementations,
such devices may be used in combination with negative pressure to
treat the wound and promote wound closure. FIG. 8 illustrates an
embodiment of a negative pressure treatment system 800 that
comprises a wound filler 802 inserted into a wound 801. The wound
filler 802 may comprise porous materials such as foam, and in some
embodiments may comprise one or more embodiments of wound closure
devices described elsewhere herein. In some embodiments, the
perimeter or top of any wound closure device inserted into the
wound 801 may also be covered with foam or other porous materials.
A single drape 804 or multiple drapes may be placed over the wound
801, and is preferably adhered or sealed to the skin on the
periphery of the wound 801 so as to create a fluid-tight seal. An
aperture 806 may be made through the drape 804 which can be
manually made or preformed into the drape 804 so as to provide a
fluidic connection from the wound 801 to a source of negative
pressure such as a pump 810. Preferably, the fluidic connection
between the aperture 106 and the pump 810 is made via a conduit
808. In some embodiments, the conduit 808 may comprise a
RENASYS.RTM. Soft Port.TM., manufactured by Smith & Nephew. Of
course, in some embodiments, the drape 804 may not necessarily
comprise an aperture 806, and the fluidic connection to the pump
810 may be made by placing the conduit 808 below the drape. In some
wounds, particularly larger wounds, multiple conduits 808 may be
used, fluidically connected via one or more apertures 806.
[0084] In some embodiments, the drape 804 may be provided with one
or more corrugations or folds. Preferably, the corrugations are
aligned along the longitudinal axis of the wound, and as such may
support closure of the wound by preferentially collapsing in a
direction perpendicular to the longitudinal axis of the wound. Such
corrugations may aid in the application of contractile forces
parallel to the wound surface and in the direction of wound
closure. Examples of such drapes may be found in application Ser.
No. 12/922,118, titled "Vacuum Closure Device," filed Nov. 17, 2010
(published as US 2011/0054365), which is hereby incorporated by
reference in its entirety.
[0085] In use, the wound 801 is prepared and cleaned. In some
cases, such as abdominal wounds, a non- or minimally-adherent organ
protection layer (not illustrated) may be applied over any exposed
viscera. The wound filler 802 is then inserted into the wound, and
is covered with the drape 804 so as to form a fluid-tight seal. A
first end of the conduit 808 is then placed in fluidic
communication with the wound, for example via the aperture 806. The
second end of the conduit 808 is connected to the pump 810. The
pump 810 may then be activated so as to supply negative pressure to
the wound 801 and evacuate wound exudate from the wound 801.
Negative pressure may also aid in promoting closure of the wound
801, for example, by approximating opposing wound margins. The
systems, devices, and methods disclosed herein may be used in
combination with a wound closure treatment or similar treatments to
monitor the progression of the wound closure, by assessing the
collapse of the wound filler 802.
[0086] Although this disclosure describes certain embodiments, it
will be understood by those skilled in the art that many aspects of
the methods and devices shown and described in the present
disclosure may be differently combined and/or modified to form
still further embodiments or acceptable examples. All such
modifications and variations are intended to be included herein
within the scope of this disclosure. Indeed, a wide variety of
designs and approaches are possible and are within the scope of
this disclosure. No feature, structure, or step disclosed herein is
essential or indispensable. Moreover, while illustrative
embodiments have been described herein, the scope of any and all
embodiments having equivalent elements, modifications, omissions,
combinations (for example, of aspects across various embodiments),
substitutions, adaptations and/or alterations as would be
appreciated by those in the art based on the present disclosure.
While certain embodiments have been described, these embodiments
have been presented by way of example only, and are not intended to
limit the scope of protection.
[0087] Features, materials, characteristics, or groups described in
conjunction with a particular aspect, embodiment, or example are to
be understood to be applicable to any other aspect, embodiment or
example described in this section or elsewhere in this
specification unless incompatible therewith. All of the features
disclosed in this specification (including any accompanying claims,
abstract and drawings), and/or all of the steps of any method or
process so disclosed, may be combined in any combination, except
combinations where at least some of such features and/or steps are
mutually exclusive. The protection is not restricted to the details
of any foregoing embodiments. The protection extends to any novel
one, or any novel combination, of the features disclosed in this
specification (including any accompanying claims, abstract and
drawings), or to any novel one, or any novel combination, of the
steps of any method or process so disclosed.
[0088] Furthermore, certain features that are described in this
disclosure in the context of separate implementations can also be
implemented in combination in a single implementation. Conversely,
various features that are described in the context of a single
implementation can also be implemented in multiple implementations
separately or in any suitable subcombination. Moreover, although
features may be described above as acting in certain combinations,
one or more features from a claimed combination can, in some cases,
be excised from the combination, and the combination may be claimed
as a subcombination or variation of a subcombination.
[0089] Moreover, while operations may be depicted in the drawings
or described in the specification in a particular order, such
operations need not be performed in the particular order shown or
in sequential order, or that all operations be performed, to
achieve desirable results. Other operations that are not depicted
or described can be incorporated in the example methods and
processes. For example, one or more additional operations can be
performed before, after, simultaneously, or between any of the
described operations. Further, the operations may be rearranged or
reordered in other implementations. Those skilled in the art will
appreciate that in some embodiments, the actual steps taken in the
processes illustrated and/or disclosed may differ from those shown
in the figures. Depending on the embodiment, certain of the steps
described above may be removed, others may be added. Furthermore,
the features and attributes of the specific embodiments disclosed
above may be combined in different ways to form additional
embodiments, all of which fall within the scope of the present
disclosure. Also, the separation of various system components in
the implementations described above should not be understood as
requiring such separation in all implementations, and it should be
understood that the described components and systems can generally
be integrated together in a single product or packaged into
multiple products.
[0090] For purposes of this disclosure, certain aspects,
advantages, and novel features are described herein. Not
necessarily all such advantages may be achieved in accordance with
any particular embodiment. Thus, for example, those skilled in the
art will recognize that the disclosure may be embodied or carried
out in a manner that achieves one advantage or a group of
advantages as taught herein without necessarily achieving other
advantages as may be taught or suggested herein.
[0091] Conditional language, such as "can," "could," "might," or
"may," unless specifically stated otherwise, or otherwise
understood within the context as used, is generally intended to
convey that certain embodiments include, while other embodiments do
not include, certain features, elements, and/or steps. Thus, such
conditional language is not generally intended to imply that
features, elements, and/or steps are in any way required for one or
more embodiments or that one or more embodiments necessarily
include logic for deciding, with or without user input or
prompting, whether these features, elements, and/or steps are
included or are to be performed in any particular embodiment.
[0092] Conjunctive language such as the phrase "at least one of X,
Y, and Z," unless specifically stated otherwise, is otherwise
understood with the context as used in general to convey that an
item, term, etc. may be either X, Y, or Z. Thus, such conjunctive
language is not generally intended to imply that certain
embodiments require the presence of at least one of X, at least one
of Y, and at least one of Z.
[0093] Language of degree used herein, such as the terms
"approximately," "about," "generally," and "substantially" as used
herein represent a value, amount, or characteristic close to the
stated value, amount, or characteristic that still performs a
desired function or achieves a desired result. For example, the
terms "approximately", "about", "generally," and "substantially"
may refer to an amount that is within less than 10% of, within less
than 5% of, within less than 1% of, within less than 0.1% of, and
within less than 0.01% of the stated amount. As another example, in
certain embodiments, the terms "generally parallel" and
"substantially parallel" refer to a value, amount, or
characteristic that departs from exactly parallel by less than or
equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree,
0.1 degree, or otherwise.
[0094] The scope of the present disclosure is not intended to be
limited by the specific disclosures of preferred embodiments in
this section or elsewhere in this specification, and may be defined
by claims as presented in this section or elsewhere in this
specification or as presented in the future. The language of the
claims is to be interpreted broadly based on the language employed
in the claims and not limited to the examples described in the
present specification or during the prosecution of the application,
which examples are to be construed as non-exclusive.
* * * * *