U.S. patent application number 16/047733 was filed with the patent office on 2020-01-30 for non-water-activated cast.
This patent application is currently assigned to LEG DEFENDER, LLC. The applicant listed for this patent is LEG DEFENDER, LLC. Invention is credited to Jason R. Hanft.
Application Number | 20200030131 16/047733 |
Document ID | / |
Family ID | 69179450 |
Filed Date | 2020-01-30 |
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United States Patent
Application |
20200030131 |
Kind Code |
A1 |
Hanft; Jason R. |
January 30, 2020 |
NON-WATER-ACTIVATED CAST
Abstract
A non-water-activatable cast has one or more layers of
sheet-like material which create a combined flexibility, stiffness,
or rigidity so that the cast may be manually positioned in
substantial contact with a lower extremity to be received within
the cast. As such, the cast is not only readily deployable by a
patient, but has predetermined flexibility located and selected to
control ankle movement within a therapeutically appropriate range,
whether used by itself or in association with a related orthosis,
such as a CAM walker. In certain applications, the cast likewise
offloads or otherwise redistributes force by virtue of the rigidity
of the plantar impact surface on such cast and the rigidity of
other cast portions.
Inventors: |
Hanft; Jason R.; (South
Miami, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LEG DEFENDER, LLC |
South Miami |
FL |
US |
|
|
Assignee: |
LEG DEFENDER, LLC
South Miami
FL
|
Family ID: |
69179450 |
Appl. No.: |
16/047733 |
Filed: |
July 27, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 5/0111 20130101;
A61F 5/0109 20130101 |
International
Class: |
A61F 5/01 20060101
A61F005/01 |
Claims
1. A cast for a lower extremity to be treated, the cast comprising:
at least two layers of sheet-like material, wherein the layers have
a predetermined, combined flexibility selected to have the layers
manually transformable from a first, pre-application configuration
before fitting on the lower extremity, to a second,
post-application configuration after the fitting on the lower
extremity; wherein the first configuration comprises a blank of the
sheet-like material extending transversely between opposite side
edges by a first amount sufficient to substantially,
circumferentially enclose the lower extremity after manipulation of
the blank, the sheet-like material extending longitudinally between
upper and lower ends by a second amount sufficient to locate the
leg and the foot of the lower extremity at the upper and lower
ends, respectively, after fitting on the lower extremity wherein
the second, post-application configuration is formed in response to
manual force applied to the blank to bring the side edges
relatively toward each other to define a volume into which the
lower extremity is received and to define an inner surface to
substantially contact opposing portions of the lower extremity when
received therein; wherein the predetermined flexibility is selected
to permit the inner surface of the cast to maintain the substantial
contact with the lower extremity during walking on the lower
extremity; and wherein the predetermined flexibility is selected to
limit at least one of plantar flexion, dorsiflexion, eversion, and
inversion of the ankle of the lower extremity by at least 50%
compared to a corresponding, non-casted movement of said ankle.
2. The cast of claim 1, wherein the predetermined flexibility is
selected to control the ankle movement by at least 80% compared to
the corresponding, non-casted movement.
3. The cast of claim 1, wherein the predetermined flexibility is
selected to limit the ankle movement to at least 90% of the
corresponding, non-casted movement.
4. The cast of claim 1, wherein one of the layers comprises an
inner layer, the material of the inner layer consisting essentially
of water-resistant material; and wherein the other of the layers
consists essentially of bands of semi-rigid polymeric material
arranged in a weave pattern to form a spica, the spica comprising a
series of overlaps and at least one opening, the spica being
configured to locate the opening at the heel of the extremity and
at least one of the intersections at the ankle joint of the lower
extremity.
5. The cast of claim 1, wherein the cast is configured to have the
inner surface of the cast directly contact the lower extremity when
received therein.
6. The cast of claim 1, wherein the cast is configured to have the
inner surface of the cast indirectly contact the lower extremity
when received therein.
7. The cast of claim 1, wherein the blank comprises a cylinder
having a cylinder wall and a slit defined therein by the opposite
side edges of the blank, the slit extending longitudinally between
the upper and lower ends of the cast, the cylinder wall being
configured so that the width of the slit is manually expandable by
a sufficient amount to position the cylinder wall around the lower
extremity.
8. The cast of claim 1, wherein the cast consists essentially of
material that is non-water-activatable.
9. The cast of claim 8, wherein one of the layers comprises an
outer layer of semi-rigid polymeric material having a thickness
ranging between 0.4 mm and 0.9 mm.
10. The cast of claim 9, wherein one of the layers comprises
cushioning material.
11. The cast of claim 9, wherein the sheet-like material is
characterized by a semi-rigidity selected to place the cast in a
weight-bearing category in terms of therapeutic uses to offload a
therapeutically significant percentage of force forward of the heel
during heel strike, and to control ankle movement at therapeutic
levels comparable to a CAM walker.
12. The cast of claim 9 wherein the sheet-like material is
characterized by a semi-rigidity selected to place the cast in a
weight-bearing category in terms of therapeutic uses to offload a
therapeutically significant percentage of force of the forefoot,
and to control foot movement at therapeutic levels comparable to a
CAM walker
13. The cast of claim 9, wherein one of the layers is located
radially inwardly from the outer layer, and comprises knitted
fabric configured to have at least one of the properties selected
from the group consisting of anti-microbial properties, insulative
properties, wicking properties, and anti-friction properties.
14. The cast of claim 9, further comprising at least one sensor
deployed at a sensor location on the inner surface of the cast, the
sensor configured to receive at least one input corresponding to at
least one of force, pressure, temperature, and acceleration, the
input further corresponding to a portion of the lower extremity
positioned at the sensor location when the lower extremity is
received in the cast.
15. A cast for a lower extremity to be treated, the cast consisting
essentially of material that is non-water-activatable, the cast
comprising: a blank comprising at least three layers of sheet-like
material dimensioned to circumferentially enclose the lower
extremity to be treated, the layers extending from an upper end to
be located on the patient's leg between the knee and the ankle to a
lower end to be located on the patient's foot between the ankle and
the toes; wherein the layers have a pre-determined, combined
flexibility selected to have the layers manually transformable from
a first, pre-application configuration before fitting on the lower
extremity, to a second, post-application configuration after the
fitting on the lower extremity; wherein the first pre-application
configuration of the blank is selected from the group consisting of
a planar sheet having opposite side edges, a cylinder, and a
spiral-wound roll; wherein the second, post-application
configuration comprises an inner surface having substantial contact
with portions of the lower extremity enclosed by the sheet-like
material when fitted to the lower extremity; wherein the
predetermined flexibility is selected so that, when the cast has
been fixed in the second, post-application configuration, movement
of the ankle in plantar flexion, dorsiflexion, eversion and
inversion is limited by 90% compared to a corresponding, non-casted
movement to control ankle movement within a therapeutically
selected range during walking on the lower extremity; wherein one
of the layers comprises an inner layer, the material of the inner
layer consisting essentially of water-resistant cushioning
material; wherein a second one of the layers consists essentially
of a semi-rigid polymeric material characterized by a semi-rigidity
selected to place the cast in a weight-bearing category in terms of
therapeutic uses, to offload a therapeutically significant
percentage of force forward of the heel during heel strike, and to
control ankle movement at therapeutic levels comparable to a CAM
walker; and wherein a third one of the layers is located radially
interior to the inner layer, the third one of the layer comprising
knitted fabric configured to have at least one of the properties
selected from the group consisting of anti-microbial properties,
insulative properties, wicking properties, and anti-friction
properties.
16. The cast of claim 15, wherein the average thickness of the
sheet-like material ranges between 0.3 mm and 35 mm.
17. The cast of claim 15, wherein the second one of the layers
comprises bands of the semi-rigid polymeric material arranged in a
weave pattern to form a spica, the spica comprising a series of
intersections and at least one opening, the spica being configured
to locate the opening at the heel of the extremity and at least one
of the intersections at the ankle joint of the lower extremity.
18. An orthosis for a lower extremity to be treated, the orthosis
comprising: a rigid frame having an inner surface; a cast
comprising a plantar portion and a leg portion, the portions having
respective outer surfaces; wherein the inner surface of the rigid
frame engages at least one of the outer surfaces of the cast;
wherein the cast is formed of at least two layers of sheet-like
material, wherein the layers have a predetermined, combined
flexibility selected to have the layers manually transformable from
a first, pre-application configuration before fitting on the lower
extremity, to a second, post-application configuration after the
fitting on the lower extremity; wherein the first configuration
comprises a blank of the sheet-like material extending transversely
between opposite side edges by a first amount sufficient to
substantially, circumferentially enclose the lower extremity after
manipulation of the blank, the sheet-like material extending
longitudinally between upper and lower ends by a second amount
sufficient to locate the leg and the foot of the lower extremity at
the upper and lower ends, respectively, after fitting on the lower
extremity wherein the second, post-application configuration is
formed in response to manual force applied to the blank to bring
the side edges relatively toward each other to define a volume into
which the lower extremity is received and to define an inner
surface to substantially contact opposing portions of the lower
extremity when received therein; wherein the predetermined
flexibility is selected to permit the inner surface of the cast to
maintain the substantial contact with the lower extremity during
walking on the lower extremity; and wherein the predetermined
flexibility is selected to limit at least one of plantar flexion,
dorsiflexion, eversion, and inversion of the ankle of the lower
extremity by at least 50% compared to a corresponding, non-casted
movement of said ankle.
19. The orthosis of claim 18, wherein the orthosis comprises a CAM
walker, and wherein the rigid frame comprises a plantar support
member and a leg bracing member, the plantar support member adapted
to receive thereon the plantar portion of the cast, and the leg
bracing member is configured to engage the leg portion of the
cast.
20. The orthosis of claim 19, wherein the cast consists essentially
of material that is non-water-activatable.
Description
FIELD
[0001] This disclosure relates to casts for use on humans, and in
particular, to casts for the lower extremities.
BACKGROUND
[0002] Although casts for treating injuries to a person's lower
extremities are available in a variety of configurations, they
nonetheless suffer from various drawbacks and disadvantages, and
the process of forming and applying casts likewise is often
inefficient, time-consuming and suboptimal for the patient's
biomechanics or lifestyle. For example, fiberglass casts, plaster
casts, and other water-activated casts generally require water for
activation or application, as well as specific timing, procedures
and protocols. Such procedures generally involve immersing rolls of
fiberglass tape, or plaster-of-Paris tape or strips in water, and
then wrapping the lower extremity to be treated Accordingly, casts
are generally applied by a trained medical professional and are
likewise time-consuming and technically challenging to apply to the
patient. After water-activated casts are set or otherwise applied
to a patient, adjustment of size and fit often requires inefficient
or difficult procedures, such as trimming or even sawing off
unwanted material.
[0003] Plaster and other prior art water-activated cast materials
may also be associated with undesirable weight, resistance to
molding, excess stiffness, and other biomechanical characteristics
that interfere with or lessen their therapeutic benefits or healing
efficiencies. Prior art casts, whether or not water-activated, may
be uncomfortable to wear on lower extremities due to the
aforementioned excess stiffness.
[0004] Furthermore, plaster, fiberglass and other water-activated
casts may not be optimal or appropriate for treating lower
extremity conditions caused by diabetes, such as foot ulcers or
other wounds, for a number of reasons. For example, breathability
of casting may be important for certain conditions to be treated,
and prior art casts often are not sufficiently breathable for such
conditions. Additionally water may carry particulates of plaster
and fiberglass into open wounds creating delay in wound healing and
possible injury to patients.
[0005] Attempts to improve the application time, ease, or the
performance of casts have achieved mixed results at best. For
example, certain casting systems make use of a circumferential mesh
sleeve of fiberglass for stretching and placing over the lower
extremity, rather than wrapping the extremity with tape. However,
such casts still generally require water activation and its
attendant disadvantages. Furthermore, the expandable mesh and other
biomechanical characteristics may not be sufficiently rigid or may
be otherwise sub-optimal to provide the desired immobilization or
limited movement of the ankle or foot, or the therapeutically
desired weight bearing functions and other desired pressure
reduction during treatment of diabetic or other foot conditions, or
during treatment of lower extremity injuries. Flexible mesh cast
systems may not be rigid enough to protect the lower extremity
during use, or may not be sufficiently rigid to transfer or
otherwise off-load weight, pressure, or other forces during the
person's gait cycle, such as during the heel-strike phase. Such
fiberglass sleeve cast systems thus may not be efficient or optimal
for particular treatments of lower extremity conditions of
diabetics or for non-diabetic conditions such as ankle sprains,
wounds, neuropathic issues, broken bones, and the like.
[0006] To address functional limitations of certain cast systems,
the casts may need to be used with overlying boots or braces, thus
complicating the treatment plan, increasing the risk that the
patient incorrectly secures the boot or brace to the cast, and thus
making treatment less therapeutically effective, less
cost-effective, extending treatment time periods, and increasing
the risk of complications.
SUMMARY
[0007] In one potential implementation of this disclosure, a cast
for treating a lower extremity includes at least two layers of
sheet-like material. The dimensions are such as to
circumferentially enclose the lower extremity to be treated, and
the two layers extend from an upper end of the cast which is
located on the patient's leg between the knee and the ankle, and a
lower end of the cast which is typically located on the patient's
foot between the ankle and the toes. The layers have a combined
flexibility which is selected so that the cast layers can be
manually transformed from a first, pre-application configuration
(that is, before being applied to the lower extremity), to a second
configuration which it assumes after being applied to the lower
extremity.
[0008] In one possible variation, the cast layers may consist
essentially of non-water-activatable materials, and may be
configured as a substantially planar or flat blank when in their
pre-application configuration.
[0009] In another implementation of the current disclosure, the
first, pre-application configuration comprises a hollow cylinder
which defines a volume sufficiently sized so that the lower
extremity can be readily received within the hollow cylinder. The
second, post-application configuration is formable in response to
manual force applied to reduce the volume of the hollow cylinder
after the lower extremity has been received therein and so that an
inner surface is in contact with the lower extremity. The
pre-determined, combined flexibility of the layers of the cast is
selected to permit the inner surface of the cast to maintain its
substantial contact with the extremity during walking and is
likewise selected to control ankle movement within a
therapeutically selected range during walking on the lower
extremity.
[0010] In the illustrated implementation of this disclosure, one of
the layers of the cast is located to be an inner layer when
received on the lower extremity. The material of such inner layer
consists essentially of cushion material which is both
water-resistant and yet breathable. A second layer is applied
outside of the inner layer and consists essentially of semi-rigid,
non-water activated fiberglass, polymeric material. In one possible
implementation, the semi-rigid polymeric material comprises bands
of the material previously arranged in adjacent and overlapping
positions, such as those of a weave pattern to form a spica. The
spica pattern comprises a series of overlaps or intersections and
an opening which is positioned to be at the heel of the extremity
when the cast is worn thereon. Similarly, one of the intersections
of the spica is an "X" like pattern, and is located at the ankle
joint of the lower extremity when the cast has been suitably
positioned thereon.
[0011] The inner surface of inner layer may be in direct contact
with the lower extremity or there may be a third, intervening layer
of knitted fabric, such that the inner layer and outer polymeric
layer contact the lower extremity indirectly, with the third layer
providing the direct contact. Rather than such third layer being a
stockingette as seen in prior art fiberglass casts, such third
layer may possess additional physical or therapeutic properties, as
discussed subsequently.
[0012] In still further implementations of the cast of this
disclosure, the semi-rigid polymeric material may have further
characteristics so that the resultant material of the cast is able
to be weight bearing. Such weight bearing characteristics may be
selected so as to be comparable to fiberglass casts and otherwise
sufficient in terms of therapeutic uses to classify the cast in a
suitable weight bearing category and associated medical
applications. Similarly, the material of the may likewise have
rigidity predetermined to offload a therapeutically significant
percentage of force forward of the heel during heel strike. The
flexibility of the cast may be selected to control ankle movement
and off-load forces away from injured areas of the foot at
therapeutic levels comparable to the biomechanical characteristics
of a CAM walker, boot, brace, or other lower-extremity orthosis
appropriate to treat the injured lower extremity.
[0013] In still another implementation of this disclosure, an
orthosis, such as a CAM walker, may include a rigid frame having
portions engaging one of the above-described implementations of the
cast of semi-rigid material.
[0014] When combined with such an orthosis, in one possible
variation, the sheet-like material of the cast may serve to
immobilize the ankle by at least 50 percent as compared to the
ankle's non-casted state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] This disclosure will be detailed and explained with
reference to the attached drawing, in which:
[0016] FIG. 1 is a side-elevational view of a cast according to one
implementation of this disclosure being worn on a lower
extremity;
[0017] FIG. 2 is an enlarged, cross-sectional view of the layers of
a cast according to one possible implementation of the present
disclosure;
[0018] FIG. 3 is top-plan view of another possible implementation
of the present disclosure;
[0019] FIG. 4 is an isometric view of another possible
implementation of the present disclosure;
[0020] FIG. 5 is a top-plan view of still another possible
implementation of the present disclosure;
[0021] FIG. 6 is a front isometric view of the implementation of
FIG. 5 worn on a lower extremity;
[0022] FIG. 7 is a rear elevational view of the implementation of
FIGS. 5 and 6;
[0023] FIG. 8 is a top-plan view of a closed-heel, open-toe
implementation of the present disclosure;
[0024] FIGS. 9-10 are front, isometric and rear elevational views,
respectively, of the implementation of FIG. 8, worn on a lower
extremity;
[0025] FIG. 11 is a top-plan view of a an open-heel, closed toe
implementation of the present disclosure;
[0026] FIGS. 12-13 are front isometric and rear elevational views,
respectively, of the implementation of FIG. 11; and
[0027] FIG. 14 is a front isometric of another possible
implementation of the present disclosure.
DETAILED DESCRIPTION
[0028] Referring now to FIGS. 1 through 7 generally, and to the
implementation shown in FIGS. 1-3 in particular, a cast 21 of the
present disclosure is adapted for use on a lower extremity to be
treated. The use of cast 21 and other cast implementations and
variations encompassed by this disclosure may be used As explained
herein, cast 21 may be applied as shown to lower extremity a
without requiring water activation. One set of applications for
cast 21 involves treatment of lower extremities of diabetics
suffering from wounds, amputations, ulcers, and other surgeries or
treatments related to the foot. Such conditions may require not
only isolation and healing of wounds and injuries facilitated by
casts, but potentially immobilization or limited ankle movement,
off-loading of forces from heel or injured areas, such as during
the gait cycle, and distribution of weight ("weight bearing")
during standing and other activities. Treatment of still other
lower extremity conditions benefitting from stabilization of the
foot or ankle joint relative to the leg are likewise contemplated.
For the sake of clarity, the use of casts disclosed herein, and
their association with "treatment" or a lower extremity "to be
treated," encompasses the full range of medical conditions, whether
the person is wounded, injured, or at-risk of developing a wound,
injury or other medical condition, and whether such condition is
dermatologic, orthopedic, neurological, biomechanical, or surgical,
whether for diabetics or other persons.
[0029] In the illustrated implementation, as seen in FIG. 3, cast
21 may assume a first, pre-application configuration 23, shown as a
cast blank 21', in which sheet-like material 25 has dimensions to
circumferentially enclose the lower extremity to be treated.
[0030] In order for material 25 to enclose a variety of sizes of
lower extremities, it will be appreciated that the surface area of
sheet-like material 25 may be chosen to give some slack or extra
room in terms of applicable dimensions. Lower extremities may also
be carrying bandaging or other surface treatments which thus may
increase the circumferential size of lower extremities to be
received within cast 21 and the volume defined by sheet-like
material 25.
[0031] In this implementation, sheet-like material 25 terminates in
an upper end 27 to be located on a patient's leg in a manner
consistent with a lower-extremity cast of any suitable length that
is distal to the knee and proximal to the ankle, and a lower end 29
to be located on the patient's foot. More particularly, cast 21
includes a pair of cut-outs 28 located relative to ends 27, 29 so
as to expose heel b and optionally ankle c when lower extremity a
is enclosed therein. The distance between upper end 27 and lower
end 29 is also selected so that, when cut-outs 28 are suitably
positioned about heel b/ankle c, lower end 29 terminates anterior
to the ankle b and posterior to toes d. Cast 21, as illustrated in
FIGS. 1-4, is an open-toe, open-heel cast.
[0032] In another implementation, seen in FIG. 4, sheet-like
material 25 is of sufficient stiffness to be formed into another
pre-application configuration 24 in the form of a hollow cylinder
31 which defines a volume 26 into which the lower extremity is
receivable. Hollow cylinder 31 includes a cylindrical wall 33 and a
longitudinally extending slit 35 formed in cylindrical wall 33 and
extending between upper and lower ends 27, 29 of cast 21. As such,
slit 35 defines opposing edges 37.
[0033] In the illustrated implementation, sheet-like material 25
comprises at least a first layer 39 and a second layer 41 (FIG. 2)
of the sheet-like material 25, the layers 39, 41 having a
pre-determined combined flexibility selected so that the layers are
manually transformable from a, pre-application configuration, such
as shown at 23 (FIG. 3), 24 (FIG. 4) to a second, post-application
configuration 40 (FIG. 1) in contact with the lower extremity when
received therein.
[0034] Sheet-like material 25 and its at least two layers 39, 41
have a predetermined combined flexibility, in particular, so that
side edges 38 of cast blank 21' may be manually displaced in the
directions indicted by arrows A, generally orthogonally to the
plane of blank 21'. By such displacement, opposite side edges 38
are brought adjacent to or overlapping each other as they are
applied around the circumference of the lower calf and foot to form
post-configuration 40 shown in FIG. 1. Furthermore, the
pre-determined flexibility of sheet-like material 25 and its two
layers 39, 41 is selected so that, when in pre-application
configuration 24, opposing edges 37 of cylindrical wall 33 may be
manually parted or separated from each other at slit 35 by a
sufficient amount so that cylinder 31 may be positioned around the
lower extremity by receiving the lower extremity into the expanded
slit 35. Thereafter, by manually urging opposing edges 37 toward
each other, volume 26 enclosed by cylindrical wall 33 is lessened
and inner surfaces 43 of the cylindrical wall 33 are brought into
substantial contact with the lower extremity received therein.
[0035] In one possible implementation, cast 21 and all of its
layers consist essentially of material that is
non-water-activatable. More generally, cast 21 is formed to consist
essentially of material which enables the end-user or medical
professional to apply cast 21 to a lower extremity by manipulation
of material 25 itself, without need for water or other curative
agents, and without the need to add additional time for setting of
the casting material, as in the case of plaster and other
comparable materials,
[0036] As such, the first layer 39 may comprise an inner layer
comprising a water-resistant or waterproof flexible material,
optionally including some cushioning material and some
breathability characteristics, such inner layer in substantial
contact with the lower extremity and having inner surface 43 in
contact (direct or indirect) with such lower extremity. Second
layer 41 is disposed to the outside of first layer 39, directly or
indirectly overlying first layer 39. In certain implementations,
outer, second layer 41 may consist essentially of bands of
semi-rigid, non-water-activated polymeric material, such as vinyl,
arranged in a suitable weave pattern, such as a pattern to form a
spica. The spica would comprise a series of intersections and at
least one opening, such opening being locatable at the heel of the
extremity when received therein and at least one of the
intersections of the spica being advantageously positioned at one
or more points on the ankle joint of the lower extremity. Second
layer 41 may comprise one or more materials selected from the group
consisting of vinyl, elastic, PVC, paper, rubber, plastic,
polyethylene, and other polymeric materials, flexible metal, wood
fibers and pulp-based derivatives, flexible ceramic components,
nylon, knitted or technical fabrics, tapes, including bands of any
of the foregoing, elasticized plaster, pre-formed fiberglass, and
alginate.
[0037] Layers 39, 41 may be suitably adhered to each other, fused,
sputtered, flocked, or otherwise processed to form a two-layer
composite and thus substantially resemble a single layer. Such
fusion and integration of the characteristics identified above for
layers 39, 41 is within the scope and definition of the two layers
when referred to herein and within the scope of this disclosure.
Suitable adhesive may likewise be used between opposing surfaces of
adjacent layers, or as a separate adhesive layer. In addition,
layer 39 may have its inner surface equipped with fugitive or other
adhesive having a tack appropriate for contact with the skin and
removal therefrom without inappropriate discomfort, such tack
likewise being sufficient to assist in maintaining inner surface 43
in substantial contact with underlying portions of the lower
extremity received in cast 21.
[0038] Similarly, a third, intermediate layer 45 may be interposed
between inner layer 39 and outer layer 41, such intermediate layer
45 providing any number of desirable properties, whether adding to
the composite flexibility or stiffness of overall cast 21,
providing padding, or providing wicking, water-resistant or
waterproof characteristics. In one variation, cast 21 comprises
three layers 39, 45, 41 wherein the inner layer 39 is a
water-resistant, breathable material, such as GORTEX, intermediate
layer 45 is of material serving primarily a padding function, and
outer layer 41 is vinyl or other polymeric material, with the
majority of flexibility or stiffness being provided by such outer
layer 41. For this three-layer implementation, the average
thickness may range (in millimeters ("mm")) from 15 mm to 35 mm,
generally, and from 9.5 mm to 15 mm for applications where less
weight-bearing or off-loading is needed. Outer layer 41 may
comprise two layers of vinyl bands, each layer having respective
thickness of 0.4 to 0.5 mm, so that layer 41 has a thickness of 0.8
to 1.0 mm, or one such vinyl layer may be used in other
applications. An outer layer 41 of semi-rigid polymeric material
ranging from 0.4 to 4.0 mm has been found suitable for many
treatment protocols, including those associated with diabetic
injuries, wounds, or at-risk conditions, but also encompassing
non-diabetic conditions.
[0039] Further variations and dispositions of multiple layers of
sheet-like material 25 are likewise within the scope of the current
disclosure. Likewise, the overall or average thicknesses of cast 21
or other implementations within the scope of this disclosure may be
below or above the ranges stated for the above-described
implementation, so long as the semi-rigidity of the resulting sheet
material 25 permits manipulation from a pre-application
configuration to a post-application configuration around the
extremity, in which the therapeutically desired immobilization or
weight-bearing is achieved.
[0040] When a layer of cast 21 is described herein as being in
"contact" with, or "overlying" the lower extremity, unless the
context indicates otherwise, such description includes both direct
and indirect contact, such that the layer operates as intended.
Thus, for example, the foregoing three layers 39, 45, 41 are each
in "contact" with opposing portions of lower extremity a, as each
imparts its characteristics thereto, including one or more of
water-resistance, padding/protection, and immobilization.
[0041] Similarly, it will be appreciated that other intersecting
weave patterns besides a spica are suitable for either outer layer
41 or first layer 39, as are any number of overlapping
configurations of tape, bands of material, and the like. Second
layer 41 and its polymeric material, as well as layers 39, 45 may
also be in a non-weave pattern or not formed of bands, but rather
be formed of a substantially uniform, composite, woven or formed
material.
[0042] Whatever the weave, pattern, uniformity, composition,
layering, or other physical characteristics of sheet material 25,
the resultant cast 21 is formed with a combined, pre-determined
flexibility not only to remain in substantial contact with the
underlying lower extremity a, but also to substantially control
movement of ankle c, especially relative to leg f, within a
therapeutically desired range, to off-load forces away from heel b
or other pressure points, and to bear sufficient weight, based on
therapeutic needs. The appropriate, therapeutically selected range
will vary depending on the lower extremity condition being
treated.
[0043] For certain lower extremity conditions, the foregoing
therapeutic goals or a desired amount of pain relief may be
accomplished by having the mechanical properties of resultant cast
21 include sufficient rigidity or stability of material 25 so that
cast 21 substantially remains in its post-application configuration
40 except for a therapeutically acceptable range of movement of
ankle c (or other lower extremity anatomy) during walking,
standing, and other anticipated activity involving the lower
extremity. In certain cases, the rigidity or stability of cast 21
achieves immobilization, pressure relief, off-loading, and the
other desired therapeutic or pain-relief goals without requiring a
separate splint, CAM walker, boot, brace, or other lower-extremity
orthosis appropriate to treat the injured lower extremity to hold
material 25 in position.
[0044] In other cases, cast 21 has a combined flexibility
pre-determined to achieve a level of immobilization by resisting
movement about ankle c and maintain post-application configuration
40 during most anticipated activities, while using cast 21 in
combination with a splint, CAM walker, boot, brace, or other
lower-extremity orthosis appropriate to treat the injured lower
extremity to provide pressure relief or off-loading to the lower
extremity being immobilized by the rigidity of cast 21. So if cast
21 has been fitted to lower extremity a in the neutral position
shown in FIG. 1, in which foot e forms an angle .beta. of about
90.degree. with leg f, the pre-determined flexibility of cast 21
restricts motion of ankle c (and related anatomy of lower extremity
a) to a therapeutically acceptable range during a therapeutically
determined percentage of anticipated patient activity. Among the
orthopedic motions of potential therapeutic interest to limit by
means of cast 21 would be the degrees of plantar flexion y and
dorsiflexion .theta..
[0045] As seen in FIG. 14, in a version of cast 21 used with a
lower-extremity orthosis, such as a CAM walker 419, while a certain
amount of weight-bearing and off-loading may be accomplished by
cast 21, additional weight-bearing and off-loading may be
accomplished by CAM walker 419.
[0046] While the mechanical properties of sheet-like material 25,
cast 21 and other aspects of this disclosure are described using
the term "flexibility," mechanical properties of cast 21 and its
material 25 may be expressed using complementary and related
mechanical properties of cast 21 and its material 25, such as the
complement of flexibility, namely rigidity, stiffness or
resiliency. Flexibility and stiffness may be determined and
expressed as a function of one or more degrees of freedom, and in
terms of moments of force. As such, flexibility and rigidity of
portions of material 25 of cast 21, whether located at, or
proximal, distal, lateral or medial of the ankle joint, may be
characterized in terms of resistance to dorsal, plantar, lateral,
or medial flexion at the ankle joint, as well as eversion or
inversion of the foot.
[0047] Similarly, rigidity of the portions of cast 21 located on
plantar surface 161 (Fig. of the foot may be expressed in terms not
only of rigidity, but also in terms of their capacity to off-load a
force at one plantar location to another, such as from the heel
toward the mid-foot, or to bear or distribute weight so as to
relieve pain points on the foot. Otherwise stated, flexibility and
rigidity may be in relation to moments of force, compressive
forces, tensile forces, shear forces, tangential, orthogonal, or
other force vectors, or resistance to such forces. Flexibility and
rigidity as applied to sheet material 25 and cast 21 may be
designed, determined, or selected by reference to established ASTM
or ISO standards associated with casts or lower-extremity orthoses.
As such, the biomechanical properties of cast 21 and sheet-like
material 25 are likewise quantifiable using the same metrics
currently used for evaluating properties and performance of current
casts, immobilizing devices, boots, or braces, such as CAM walkers,
or other lower-extremity orthoses appropriate to treat the lower
extremity.
[0048] In a further variation of this disclosure, there may be a
plurality of casts 21, each having an associated, pre-determined
flexibility associated therewith, so that a practitioner may select
an appropriate one of the casts 21, and form it from its
pre-application configurations 23, 24 to its second,
post-application configuration 40, and thus have associated
therewith the pre-determined flexibility of material 25 for the
therapeutically desired range of motion for the condition being
treated.
[0049] In still further implementations, it will be appreciated
that the pre-determined, combined flexibility for a given portion
of cast 21 may vary depending on its location on blank 21' or
cylindrical wall 33 relative to ends 27, 29. Thus, for example,
those portions of sheet-like material 25 likely to be subjected to
increased bending moments or other forces during walking or other
activity of the lower extremity, such as plantar impact surface 61
(FIG. 1) may be designed to have increased rigidity (less
flexibility) at or adjacent to such regions to maintain the
substantial contact, the therapeutically desired range of ankle
movement, or the other desired therapeutic benefits to cast 21.
[0050] Second layer 41, or the combined flexibility of sheet
material 25, may be selected so that cast 21 is suitable for
bearing weight or distributing downward force of the user, such as
when standing. With reference to the kinetics of the gait cycle,
the flexibility (or its complementary property of rigidity) may be
such as to offload a therapeutically significant percentage of
force forward of the heel, or to bear weight or distribute force of
the user during heel strike, toe-off, propulsive, or other phases
of the gait cycle. The flexibility and rigidity of cast 21 may be
selected to control ankle movement during the gait cycle at levels
comparable to those of a water-activated cast or to those of a CAM
walker or any number of boots, braces, or other lower-extremity
orthoses appropriate to treat the lower extremity, and may likewise
bear/transfer weight, thereby eliminating the need to use such
braces and boots. Again, though cast 21 may permit a lower
extremity received therein to become weight-bearing and otherwise
not require additional bracing or support structure, this
disclosure is not so limited, and the cast 21 herein may be used in
conjunction with other orthoses, such as a CAM walker, boot, brace,
or other lower-extremity orthosis appropriate to treat the lower
extremity.
[0051] Cast 21 may be implemented to include another layer, either
adhered or otherwise fused to inner surface 43 of inner layer 39 or
manually separable therefrom, forming a lining or sock (not shown).
In one suitable implementation, this lining or sock comprises
knitted or non-woven technical fabric or fabrics, the fabric
configured to have properties which benefit treatment of the lower
extremity received therein. The lining or sock may be in direct
contact with the lower extremity, such that overlying inner layer
39 (and outer layer 41) are in indirect contact with such lower
extremity. The lining or sock may have anti-microbial properties,
insulative properties, wicking properties, or anti-friction
properties, or any combination of the foregoing.
[0052] As such, in one implementation, not only does cast 21
consist essentially of material that is non-water-activatable, but
also such cast comprises the following layers of sheet-like
material, whether separable or fused together, the four layers
circumferentially enclosing and disposed relative to the lower
extremity, from innermost to outermost as follows: a lining or
sock, layer 39 of water-resistant/waterproof material layer 45 of
padded material, and semi-rigid layer 41.
[0053] Variations to pre-application configuration 23 are
contemplated by this disclosure, such that material 25 need not be
in the planar form of blank 21' or cylindrical form 31, may not
require slit 35, and may not be pre-formed. For example, the cast
layers 39, 41 may be tightly rolled when in their pre-application
configuration. Pre-application configurations may likewise include
more than one piece, such as one flat or cylindrical piece for the
leg and one for the foot, such multiple pieces having portions
designed for overlapping at the ankle. Still other pre-application
configurations are possible.
[0054] In still other implementations, referring more particularly
to FIGS. 5-7, cast 121 and its corresponding blank 121' may have
sheet material 25 (with a variety of functional layers as described
with reference to FIGS. 1-4, especially FIG. 2. Sheet material 25
is arranged so as to include one or more tabs 151, may exclude the
cut outs 28 shown in the embodiment of FIGS. 1-4, and may include a
foldable section 153 which can be disposed anteriorly around the
toes. As such, sheet material 25 may assume a pre-application
configuration 134 corresponding to blank 121' and a
post-application configuration 140, corresponding to the closed
toe, closed heel arrangement shown. Two apertures 159 are suitably
sized and located on blank 121' to potentially receive all or part
of the malleoli of ankle c therein when cast 121 has been
transformed into its post-application configuration 140 engaging
lower extremity a, with the goal of improving fit or comfort.
Similarly opposite sides 138 have been provided with detents 157 to
potentially become located above the heel proximate to the Achilles
tendon when in its post-application configuration 140 with the goal
of improving fit or comfort. As such, cast 121 and its
corresponding blank 121' form a closed heel, closed toe
configuration as shown in FIGS. 6 and 7.
[0055] Still further implementations of this disclosure may enclose
or expose heel, toe and other portions of lower extremity a to
effectuate desired treatments. As such, referring to FIGS. 8-10, a
closed-heel, open-toe cast 221 (and corresponding blank 221')
includes sheet-like material 225 having the functional layers
discussed previously, such as inner and outer layers 39, 41 (FIG.
2), and upper and lower ends 227, 229 sized and located similarly
to upper and lower ends 27, 29 of FIG. 3, with opposite,
longitudinal side edges 238, and apertures 259 and detents 257
similar to apertures 159 and detents 157 of FIGS. 5-7. Blank 221'
may be manipulated from a substantially planar pre-application
configuration 223, such as by moving opposite side edges 238
generally orthogonally to the plane of FIG. 8 as indicated by
arrows A, and sheet material 225 has a preselected semi-rigidity to
hold its post-application configuration 240 shown in FIGS. 9 and
10. As a result, blank 221' encloses heel b, yet leaves toes d
open. A self-sticking surface treatment portion 230 may be
provided, here extending longitudinally along one of the side edges
238, to assist in avoiding peel back of corresponding side edge 238
when in post-application configuration 240 (FIGS. 10, 11).
[0056] Referring to FIGS. 11-13, an open-heel, closed-toe cast 321
(and corresponding blank 321') includes upper and lower ends 327,
329 sized and located as discussed with reference to the previous
implementations, including cut-outs 328 to generate an opening
about heel b but toe portion 353 is manually moveable to enclose
toes d, as shown. Blank 321' is composed of sheet material 25 (like
reference numbers throughout this disclosure referring to like
elements in previously described implementations). Similarly,
variations on previously described features have been given
corresponding reference numbers with respect to cast 321, including
cut-out portions 328 to expose the heel when received therein, tabs
351, and side edges 338. As previously described, blank 321' may be
manipulated into a post-application configuration 340 (FIGS. 12-13)
from pre-application configuration 323 (FIG. 11).
[0057] An orthosis 419 incorporating features of the casts
described herein is shown in FIG. 14. Orthosis 419 in this
implementation comprises a CAM walker with a rigid frame 430 and
cast 421. Rigid frame 430 has an inner surface 432 fouling a volume
suitable for receiving cast 421 therein. Cast 421 has features and
structures as described with reference to the previous
implementations of casts 21, 121, 221, or 321, including sheet
material 25 as described herein. Cast 421 has been manipulated into
its post application configuration 440 around lower extremity a.
Cast 421 has a corresponding blank as described previously for the
other implementations, formed of semi-rigid material with suitable
flexibility/rigidity described above. Cast 421 has a plantar
portion 434 and a leg portion 436, the portions having respective
outer surfaces 438. Inner surface 432 of rigid frame 430 engages at
least one of the outer surfaces 438 of the cast 421.
[0058] In one possible variation, cast 421 is foil led of at least
two layers of sheet-like material, with the layers having a
predetermined, combined flexibility selected to have the layers
manually transformable from a first, pre-application configuration
in the form of the blank with side edges, such as blanks 21', 121',
221', and 321' previously discussed, before fitting on the lower
extremity, to the second, post-application configuration 440 after
the fitting on the lower extremity.
[0059] As in previous implementations, post-application
configuration 440 is formed in response to manual force applied to
the blank to bring side edges of the blank relatively toward each
other to define a volume into which the lower extremity is received
and to define an inner surface to substantially contact opposing
portions of the lower extremity when received therein. The
predetermined flexibility is selected so that cast 421, separate
and apart from frame 430, limits at least one of plantar flexion,
dorsiflexion, eversion, and inversion of the ankle of the lower
extremity by at least 50% compared to a corresponding, non-casted
movement of said ankle.
[0060] Rigid frame 430 may include a plantar support member 450 and
a leg bracing member 545. Plantar support member 450 is sized so
that it may receive thereon the plantar portion 434 of the cast,
and the leg bracing member 545 is configured to engage the leg
portion 436 of cast 421.
[0061] Testing was performed for one of cast implementations set
out herein (without the related rigid orthosis), in which inner
layer 39 comprises water-resistant material, layer 45 comprises
padding, and outer layer 41 comprises two, 0.43 mm-thick layers of
vinyl bands in a woven pattern forming a spica. It was found that
the foregoing combination of non-water activated materials formed a
combined flexibility to achieve desired therapeutic goals after
application to a lower extremity. For example, measurements were
taken of the range of motion of the ankle joint, subtalar joint,
metatarsophalangeal joints, and gait analysis--all in relation to
the motions of dorsiflexion, flexion, plantar flexion and
inversion/eversion. The above-described testing was performed on a
lower extremity having a base-line, non-casted range of motion. For
the ankle joint, results/testing showed dorsiflexion limited to 90%
compared to the non-casted range of motion, plantar flexion limited
to 95% of the otherwise non-casted range of motion and ankle joint
inversion/eversion limited to 95% compared to a non-casted range of
motion. For the subtalar joint, motions were limited by more than
90% compared to non-casted. With regard to the metatarsophalangeal
joints, plantar flexion was limited to 90%, while dorsiflexion was
limited to 80%, the foregoing again compared to the base-line
non-cast-range of motion.
[0062] With regard to the gait analysis, stride length was
shortened by application of cast 21, speed of floor propulsion
decreased. No true heel strike was witnessed, thereby achieving
off-loading. Steppage gait occurred with contact made with
substantially all of the plantar surface of the foot from the
metatarsophalangeal joints proximal to the heel. Rigidity and/or
flexibility of cast 21 was such as to substantially limit the range
of motion at the ankle and achieve slight, circumductive gait, with
subjects reporting transmission of pressure/force otherwise felt at
the foot up the leg to the tibia and calf area.
[0063] Operation and use of the cast 21 is apparent from the
foregoing description. A patient, medical practitioner or other
third party, by manual force, is able to transform the
pre-application configuration of sheet-like material 25, 134 and
its multiple layers 39, 41, to a post-application configuration 40,
140 around the lower extremity to be treated as shown in FIGS. 1,
and 6-7, respectively. The resultant cast 21 exhibits mechanical
properties of flexibility/rigidity selected to provide control of
ankle movement or substantial immobilization, weight-bearing,
offloading of pressure, a therapeutic environment, and other
therapeutic benefits during the biomechanics of walking or other
activity.
[0064] Cast 21 may be used as part of a computer-implemented system
to diagnose, analyze, or otherwise evaluate performance of cast 21
itself, as well as any associated CAM walker, boot, brace, or other
lower-extremity orthosis associated with the lower extremity under
treatment. Data may be gathered by associating cast 21 with sensors
capable of obtaining inputs on force, pressure, temperature,
acceleration and the like, when cast 21 is being worn on the lower
extremity a. In one possible implementation, such sensors are
deployed at suitable, corresponding locations on inner surface 43
of cast 21, such as on the portion of the inner surface opposing
the plantar surface of the lower extremity received therein. Data
thus gathered may be used as inputs to modify the rigidity or other
parameters of cast 21, or to design or modify the design of cast 21
or of orthoses associated with the lower extremity treatment, as
set out in U.S. Pat. No. 9,201,413, the contents of which are
incorporated herein by reference.
[0065] The foregoing is provided for purposes of illustrating,
explaining, and describing implementations of this disclosure.
Thus, although specific arrangements have been illustrated and
described herein, other arrangements may achieve the same or
similar purposed and may be substituted for the specific
arrangement shown. Combinations of the above arrangements, and
other arrangements not specifically described herein, will be
apparent to those of skill in the art upon reviewing the above
description. Therefore, it is intended that the disclosure not be
limited to the particular arrangement(s) disclosed herein, and that
such alternatives and equivalents are within the spirit and scope
of this disclosure, as defined in the following claims.
* * * * *