U.S. patent application number 15/766618 was filed with the patent office on 2018-10-18 for temperature regulating footwear.
This patent application is currently assigned to UNIVERSITY OF PITTSBURGH - OF THE COMMONWEALTH SYSTEM FOR HIGHER EDUCATION. The applicant listed for this patent is UNIVERSITY OF PITTSBURGH-OF THE COMMONWEALTH SYSTEM OF HIGHER EDUCATION. Invention is credited to David M. Brienza, Patricia Karg, David Smeresky, Yi-Ting Tzen.
Application Number | 20180295930 15/766618 |
Document ID | / |
Family ID | 58488457 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180295930 |
Kind Code |
A1 |
Brienza; David M. ; et
al. |
October 18, 2018 |
TEMPERATURE REGULATING FOOTWEAR
Abstract
A footwear product with an integrated active temperature control
system comprising: an upper; a sole comprising an insole comprising
one or more thermo-conductive inserts or plugs; a midsole disposed
between the insole and an outsole; wherein the midsole comprises
one or more cooling elements selected from the group consisting of:
an air flow cooling element, a liquid cooling element, a
thermoelectric cooling element; and one or more heat sinks disposed
in the midsole, outsole or between the midsole and outsole.
Inventors: |
Brienza; David M.;
(Pittsburgh, PA) ; Karg; Patricia; (Pittsburgh,
PA) ; Smeresky; David; (Pittsburgh, PA) ;
Tzen; Yi-Ting; (Pittsburgh, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF PITTSBURGH-OF THE COMMONWEALTH SYSTEM OF HIGHER
EDUCATION |
Pittsburgh |
PA |
US |
|
|
Assignee: |
UNIVERSITY OF PITTSBURGH - OF THE
COMMONWEALTH SYSTEM FOR HIGHER EDUCATION
PITTSBURGH
PA
|
Family ID: |
58488457 |
Appl. No.: |
15/766618 |
Filed: |
October 6, 2016 |
PCT Filed: |
October 6, 2016 |
PCT NO: |
PCT/US2016/055776 |
371 Date: |
April 6, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62238057 |
Oct 6, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A43B 7/148 20130101;
A43B 7/144 20130101; A43B 7/005 20130101; A43B 3/0005 20130101;
A43B 7/1425 20130101; A43B 13/189 20130101; A43B 13/188
20130101 |
International
Class: |
A43B 7/00 20060101
A43B007/00; A43B 13/18 20060101 A43B013/18; A43B 3/00 20060101
A43B003/00; A43B 7/14 20060101 A43B007/14 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with government support under grant
#DGL 1144584. The government has certain rights in the invention.
Claims
1. A footwear product with an integrated active temperature control
system comprising: an upper; a sole comprising an insole comprising
one or more thermo-conductive inserts or plugs; a midsole disposed
between the insole and an outsole; wherein the midsole comprises
one or more cooling elements selected from the group consisting of:
an air flow cooling element, a liquid cooling element, a
thermoelectric cooling element; and one or more heat sinks disposed
in the midsole, outsole or between the midsole and outsole.
2. The footwear product of claim 1 wherein the thermo-conductive
inserts or plugs comprise one or more materials selected from the
group consisting of a gel, an open-cell polyurethane foam, a
closed-cell expanded rubber, a low friction interface material, and
a polyethylene thermoplastic foam.
3. The footwear product of claim 1 wherein a separate one of the
one or more cooling elements is disposed adjacent to or underneath
each of the one or more the thermo-conductive inserts or plugs.
4. The footwear product of claim 1 wherein each of the one or more
cooling elements comprises an active solid-state electrical
device.
5. The footwear product of claim 1 wherein each of the one or more
cooling elements comprises a thermo-electric cooling element having
an active solid-state electrical device that operates on the
Peltier effect.
6. The footwear product of claim 1 further comprising a power
source for the one or more cooling elements.
7. The footwear product of claim 6 wherein the power source
comprises rechargeable batteries that may be recharged when in use
and/or when not in use.
8. The footwear product of claim 1 further comprising a control
system or a closed loop passive control system to control the
amount of heat being removed from the footwear product.
9. The footwear product of claim 1 wherein the one or more
thermo-conductive inserts or plugs also provide cushioning to
control pressure and/or shear and are each disposed in a portion of
the insole contacting a high-pressure area or other area of the
plantar surface of a foot disposed in the footwear product that
normally experiences tissue breakdown, such as the first metatarsal
or heel.
10. The footwear product of claim 1 further comprising a power
source for the one or more heat sinks.
11. The footwear product of claim 1 wherein the one or more heat
sinks are passive or body-powered.
12. The footwear product of claim 1 wherein each of the one or more
heat sinks employs an air movement system that uses convection to
move heat from each heat sink into the environment outside of the
footwear product.
13. The footwear product of claim 1 wherein each of the one or more
heat sinks employs the loading and/or unloading of the sole during
gait to create airflow through or across each heat sink to move
heat from each heat sink into the environment outside of the
footwear product.
14. The footwear product of claim 1 further comprising temperature
and/or pressure sensor(s) associated with each of the one or more
thermo-conductive inserts or plugs.
15. The footwear product of claim 14 further comprising a control
system or CPU to control the amount of heat being removed from the
footwear product; wherein the control system or CPU has an input
for setting the temperature to be maintained or to not be exceeded
at each location of the one or more thermo-conductive inserts or
plugs.
16. The footwear product of claim 15 wherein the input is disposed
inside or outside of the footwear product and/or is operatively
connected wirelessly or by wire to the control system.
17. The footwear product of claim 15 wherein the integrated active
temperature control system is activated upon exceeding a preset
pressure on one or more of the pressure sensors.
18. The footwear product of claim 1 wherein each of the one or more
heat sinks comprises a metal component and/or a thermal-conductive
foam component.
19. The footwear product of claim 1 wherein a single heat sink
comprises one or more metal components and/or a thermal-conductive
foam components and wherein the single heat sink directly contacts
each of the one or more thermo-electric cooling elements.
20. A kit for retrofitting a footwear product to include an
integrated active temperature control system, wherein the kit
comprises one or more of the following items: a plug, having an
upper surface comprising a low friction interface material and
comprising a thermally conductive material, wherein the plug is for
placement in an opening in an existing insole, a heat sink and
cooling device for placement in the midsole and/or outer sole of
the footwear product and a thermal paste or adhesive for connecting
the thermal conductive material of the plug to the cooling device
and/or heat sink.
21. The kit of claim 20 wherein the cooling device is selected from
the group consisting of: an air flow cooling element, a liquid
cooling element, a thermoelectric cooling element.
22. The kit of claim 20 wherein the plug comprises one or more
materials selected from the group consisting of: a gel, an
open-cell polyurethane foam, a closed-cell expanded rubber, a
cushioning material and a polyethylene thermoplastic foam.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of
U.S. provisional patent application Ser. No. 62/238,057, filed on
Oct. 6, 2015, the entirety of which is incorporated herein by
reference for all purposes.
TECHNICAL FIELD
[0003] The present disclosure generally relates to apparatus for
regulating temperature with footwear and kits for retrofitting
footwear for the same purpose.
BACKGROUND OF THE DISCLOSURE
Description of the Need and Target Population
[0004] An estimated 1.6 million people in the United States live
with limb loss. By 2050 that number may be as high as 3.63 million
due to growth in the aging population and an increase in the number
of people with dysvascular diseases such as diabetes. This
prevalence reflects the significance of amputations and serves as a
compelling basis for future research. Prior to amputation,
individuals with diabetes are at a high risk for soft tissue
complications. According to the Centers for Disease Control and
Prevention, diabetes mellitus affects 25.8 million people, which is
about 8.3% of the U.S. population. People with diabetes have a 25%
lifetime risk of developing diabetic foot ulcers (DFU), and once an
ulcer is formed, 84% of the cases will lead to lower extremity
amputation (LEA). A study conducted at the Karolinska University
Hospital in Sweden reported that 88% of non-traumatic lower
extremity amputations were performed due to foot ulceration,
confirming the high risk associated with this condition.
[0005] Development of DFU and subsequent LEA affects a person's
health and function as well as quality of life, including reduction
or loss of mobility, independence, inability to work, anxiety of
possible development of new ulcers, depression and social
isolation. In addition, treating DFU is costly; diabetic foot
ulcers were estimated to cost the Medicare system 1.5 billion
dollars annually. These costs include treatment of non-infected and
infected ulcers, ulcers that progress to amputation, surgery and
post amputation treatment.
Need for Innovation in Therapeutic Footwear
[0006] Diabetic foot ulcers are multifactorial conditions, and the
major underlying causes are peripheral neuropathy and peripheral
vascular ischemia. Peripheral neuropathy causes foot deformities,
lack of sensation, and dry skin that is susceptible to tearing.
Changes in microvascular function include impaired vasodilator
response, decreased blood flow, and endothelial dysfunction leading
to tissue ischemia of the lower extremities. These alterations lead
to repetitive high pressure points at the bony prominences,
occlusive arterial disease and eventually ischemia in the lower
extremity. Current insoles prescribed to patients at risk focus
only on reducing the pressure concentrated at the bony prominences,
however pressure is inevitable with daily activities (e.g.,
walking, standing). There is a need to develop therapeutic footwear
insoles that will optimize tissue viability during ambulation and
other daily activities.
[0007] Thermal control of the skin has been proven to maintain
tissue viability during ischemia in animals and humans; this is
primarily because lowering temperature reduces the ischemic tissue
metabolism by 6-13% per .degree. C. Two iconic animal studies
investigated the effect of temperature on ulcer development. Kokate
et al., performed histological examination of the skin in swine
after the skin was subjected to 100 mmHg of pressure at different
temperatures ranging from 25 to 45.degree. C. for five hours. They
found that the higher the skin temperature, the deeper and more
severe the tissue damage. Iaizzo et al. found that with temperature
as low as 25.degree. C., no ulceration was noted after the skin was
loaded with 100 mmHg of pressure for up to ten hours. Human studies
by our research team demonstrated a similar protective effect of
temperature control on young healthy adults and adults with spinal
cord injury. In these studies, skin temperature maintained at
25.degree. C. was compared to no temperature control on sacral skin
under 60 mmHg of pressure for 30-40 minutes. Blood flow measures
showed that the severity of tissue ischemia (determined using
magnitude of the reactive hyperemic response) was reduced in both
populations when thermal control was applied.
[0008] Only one study was found in the literature that applied
local cooling for the purpose of diabetic foot ulcer prevention.
This study investigated whether simple cooling of the foot after
brisk walking would reduce the temperature to pre-activity level,
which may help to reduce the inflammatory response that leads to
skin breakdown. They found that the foot skin temperature increased
from 79.degree. F. to 88.degree. F. after 15 minutes of brisk
walking for healthy adults. Air cooling (passive) and water cooling
(active) methods were applied to the feet after brisk walking, and
active water cooling of the feet was able to reduce the skin
temperature to pre-activity level right away, while passive air
cooling took about 17 minutes to reduce the skin temperature to
pre-activity levels. Results of this study indicate that
implementing active cooling of the foot is more efficient in
reducing temperatures. No studies were identified that investigated
the effect of cooling in people with diabetic neuropathy, nor the
effect of thermal control applied during mobility and daily
activities.
Beneficial Impact on the Target Population
[0009] According to the Diabetic Foot Disorders Clinical Practice
Guideline, a multidisciplinary team approach has proven to be the
optimal method of treating DFU and lowering the rate of LEA. About
40% of amputation caused by diabetes could be prevented with this
multidisciplinary team approach to wound care. Provision of insoles
and therapeutic footwear is a crucial part of this multifaceted
foot ulcer prevention strategy. Therefore, developing therapeutic
footwear that optimizes tissue viability during ambulation and
other daily activities will be beneficial in enhancing the health
and function of the target population by improving mobility,
independence, social participation, and preventing the
complications of DFU and subsequent LEA.
[0010] Plantar pressure reduction insoles are currently prescribed
to help prevent ulceration by reducing the adverse effect of
peripheral ischemia. However, no therapeutic footwear has been
developed mainly for the purpose of enhancing tissue viability
during repetitive ischemic events (e.g., walking, standing).
[0011] The strong evidence from previous animal and human studies
on the benefits of active cooling, and the need for improved
prevention of foot ulcers for people with diabetic neuropathy
indicates there is benefit in exploring the implementation of
active cooling in diabetic footwear. Implementing thermal control
features in the insoles of footwear can improve tissue viability
during repetitive ischemia, i.e., during ambulation and other
activities of daily living, and reduce the risk for developing
diabetic foot ulcers.
[0012] State-of-the-Art in Orthotic and Thermal Diabetic Foot
Care
[0013] Appropriate footwear is an important component of the
overall treatment plan for people with diabetes to prevent serious
foot complications. Current orthotic intervention consists of
specialized insoles and footwear. A diabetic insole, as defined by
Medicare, is a total contact, multiple density, removable inlay
that is directly molded to the patient's foot or a model of the
patient's foot using suitable materials with respect to the
individual patient's needs. These insoles must be delivered with an
extra depth shoe that is defined as having the following
properties; a full-length heel-to-toe filler which when removed
provides a minimum of 3/16'' additional depth for the insertion of
custom-molded or customized insert, made from leather or equivalent
material, a shoe closure, and is available in a multitude of sizes
with a minimum of three widths. These definitions give the
certified orthotist the choice of material selection in order to
properly customize the patient's insole. Common materials used in
the production of diabetic inserts include open-cell polyurethane
foam (PPT.TM., Poron.TM.), closed-cell expanded rubber
(Spenco.TM.), polyethylene thermoplastic foams (Plastazote.TM.),
and a variety of other materials of varying mechanical properties.
The foam-based materials commonly used in clinical practice have
been found to decrease plantar pressure, but were less effective at
reducing shear forces than gel-based materials.
[0014] Current devices used in diabetic ulcer prevention and
healing include the use of total contact casting, half-shoes,
custom insoles, ankle-foot orthoses (AFO), and the Charcot
restraint orthotic walker (CROW). The primary goal of these devices
is the reduction of plantar pressure through off-loading of the
high-pressure areas, with the goal of decreasing stress on the
tissue allowing it to heal. When considering shoe orthoses, the
most effective pressure relieving insole is a multi-density insert
consisting of a higher density material for support and a less
dense material to create good contact with the plantar surface of
the user's foot. The higher density material is chosen in order to
support the foot in a therapeutic position, which assists with the
reduction of pressure. A common technique for relieving areas of
high pressure is to modify the insole by replacing the high-density
material with less dense material, such as Poron.TM., under the
affected area of the foot. By situating these "plugs" under the
current areas of high pressure rather than the area of previous
ulceration, improved pressure distribution and reduced areas of
high pressure can be achieved; a key factor in diabetic foot ulcer
prevention. Specialized insoles for prevention of diabetic foot
ulcers are currently being developed with features to relieve
excess pressure, warn the user of possible issues, and to measure
micro-environmental conditions (e.g., moisture, temperature) of the
feet. One such insole is the Smart Insole, patented by Shoureshi
and Albert, which focuses on the measurement of temperature,
moisture, and pressure in order to warn the user of high risk
conditions that can lead to ulceration.
[0015] FIG. 1 shows a traditional extra depth footwear design 10
comprising soft leather 12 padded with foam; an extended heel
counter 13, a customized orthotic 14, spacer 15, firm rearfoot
board 16, a hidden depth design 17 and a cushioning outsole 18.
[0016] Heating and electric stimulation has been used in diabetic
foot care to increase blood flow in areas with injured tissue to
promote tissue regeneration. Heating and electric stimulation is
viable only for treating ulcers and only when the affected area is
completely offloaded to allow unimpeded blood flow. We propose
technology innovation through the implementation of cooling in
footwear, which focuses on the prevention of ulceration while the
foot is exposed to loading, as opposed to healing of currently
affected areas of the foot. Our prior research has shown that
cooling loaded tissue reduces metabolic rate and accumulation of
cellular waste products, two factors known to lead to ulceration.
This approach has been previously explored in footwear through the
use of passive cooling packs, though not implemented in footwear
products or clinical practice.
Thermal Control Therapeutic Footwear (TCF)
Description of the Need and Target Population
[0017] The target population of this development project is
individuals with diabetic neuropathy who use orthotic footwear and
are at risk for diabetic foot ulcers and subsequent amputation.
According to the Centers for Disease Control and Prevention,
diabetes mellitus affects 25.8 million people, which is about 8.3%
of the U.S. population. People with diabetes have a 25% lifetime
risk of developing diabetic foot ulcers (DFU). Once an ulcer is
formed, about 84% of the cases will proceed to lower extremity
amputation (LEA). A study conducted at the Karolinska University
Hospital in Sweden reported that 88% of non-traumatic lower
extremity amputations were performed due to foot ulceration,
confirming the high risk associated with this condition [10].
[0018] In the modern era, a pandemic has reached new levels in the
United States: Diabetes. Diabetes, which causes glucose regulation
to be hampered in the body, is a set of two distinct diseases. Type
1 diabetes is a disorder that prevents the pancreas from properly
producing insulin. Since insulin is responsible for glucose
regulation in the body, people who develop this condition cannot
regulate their glucose naturally and must use injected insulin to
assist their bodies. (Mayo Clinic Staff, 2014a) Type 2 diabetes is
commonly a lifestyle disease that can be classified by the body's
resistance to insulin or decreased production of insulin, therefore
making regulation of the amount of glucose available in the body
difficult. (Mayo Clinic Staff, 2014b) This leads to both hypo and
hyperglycemia, which are both dangerous acute conditions. However,
as regulation of this disease gets better, the long-term effects
are becoming more lucid.
[0019] Long-term effects of the body's inability to regulate
glucose range from connective tissue changes to neurologic issues
in the periphery. (Mayo Clinic Staff, 2014b) One of these potential
conditions is the diabetic foot ulcer (DFU). A DFU is defined as
"an open sore or wound that occurs in approximately 15 percent of
patients with diabetes and is commonly located on the bottom of the
foot." (American Podiatric Medical Association, 2015) While this
may seem minor, it is one of the most damaging and deadly
conditions a diabetic can develop. DFUs, along with other
comorbidities such as peripheral arterial disease (PAD), are
responsible for the death of 182,000 diabetics yearly. (Mroczek,
2008). With 15% of diabetics developing an ulcer during their
lifetime, and an incidence rate of 1%-4.1% in the population, DFUs
are among the most common issue diabetics face, as they get older.
(Mroczek, 2008). Along with causing death, DFUs are the number 1
reason for non-traumatic amputation in the U.S. (Mroczek, 2008).
While amputation is often the best course of action and a
lifesaving technique, it is not a treatment option that is chosen
lightly and has many issues that accompany it as well. As
treatments for healing DFUs are constantly improving, the industry
of preventing these wounds has remained stagnant and must be
further developed and researched.
[0020] Current preventative technology focuses on the management of
pressure profiles through the use of specialized footwear and
insoles. The entire footwear system is designed to protect the foot
from damage that can occur during everyday activities. Extra-depth
shoes are designed to provide increased room around the toes to
prevent rubbing. Additionally, they have no seams inside the shoe
to prevent injury and extra depth allows for a specialized insole
to be fitted inside of the footwear. These insoles are designed to
move pressure away from the bony prominences of the foot such as
the 1st and 2nd metatarsophalangeal (MTP) joint and specials areas
of deformations such as those found in Charcot Foot, a disease
sometimes present in diabetics which causes the foot to have a
rocker bottom deformity. The need for this pressure relief under
the MTP joints can be observed due to a majority of DFUs occurring
at the forefoot and midfoot. (Tamir, Daniels, Finestone, & Nof,
2007). Treatments are effective if used properly, though misuse or
poorly made insoles allow for DFUs to develop even in feet that are
well maintained. Due to this, new interventions must be explored to
assist with the control of DFUs; one possible intervention is
temperature regulation at the high-pressure areas of the foot.
[0021] Temperature has already been shown to have a positive effect
on the healing of DFUs through the use of heating. (Petrofsky,
Lawson, Berk, & Suh, 2010). The use of cooling to prevent
pressure ulcers (PU) is another recent area of interest, and
exploring the use of temperature for prevention as well as healing
is a worthwhile endeavor. With the goal of preventing an ulcer
prior to healing, the risk of infection, amputation, and other
complications inherent in a non-healing wound can be reduced. Using
cooling to prevent DFUs can be broken down into three possible
mechanisms: decreasing in metabolic load, decreasing the reactive
hyperemia, and decreasing ischemia in the area being affected.
(Kokate et al., 1995). Currently, no one has attempted this method
for effective maintenance of tissue integrity, although this method
has been proposed in patents with similar designs. (Moreshead,
2012; Vogt, 2012).
[0022] Thus, there is a need for the implementation of advanced
technology into everyday practice of DFU prevention. While many
different practices have been attempted in healing, including
increasing temperature, application of an electrical current
through the wound, and using cadaver tissue for bandaging, no
realistic methods for DFU prevention outside the use of different
materials and the method of pressure reduction have been
considered.
[0023] One of the major issues present in diabetic feet is that the
damage that occurs causes ischemia that both increases the
temperature and pressure under the damaged area. Ischemia is a
common biological pathway that happens when tissue takes damage.
Ischemia is often associated with moving extra lymphatic fluid
towards the site of the tissue damage allowing for better
management of the dead tissue. Often this reaction may cause extra
damage or discomfort so a common treatment is the application of a
cold compress directly to the affected area. Looking at this in a
similar manner to a common inflammatory response allows for the
assumption that cooling may help to prevent further damage from
occurring.
[0024] Pressure is currently the main direct indicator for
ulceration in DFUs. Pressure can lead to injury through continuous
loading of tissue during gait and acute damage through
instantaneous extremely high pressures. Due to trauma being a major
contributor for causing ulceration, it is extremely important for
clinicians to manage the pressure. In DFUs, this trauma can be
caused due to continuous oscillation of pressure on the plantar
surface of the foot at specific high pressure areas. Plantar
pressure on the feet of diabetic neuropathy patients is much larger
than the pressure normally required for the formation of other
similar pressure related ulcers. Ulceration can be related to the
amount of pressure over time that has been applied to a portion of
the body.
[0025] The pressure at the metatarsal phalangeal joints of an
ambulatory diabetic neuropathy patient is approximately 100
kilopascals while wearing pressure-relieving footwear and 1000
kilopascals while barefoot. (Petre, Tokar, Kostar, & Cavanagh,
2005). The barefoot pressure of diabetic patients is much higher
than non-diabetic patients. This is due to a variety of reasons,
although it has much to do with both the pathomechanics of the foot
and the tissue changes that occur in diabetics. The pathomechanics
of the foot that change the pressure during gait and during stance
include the loss of motion at the joints, loss of function of the
intrinsic musculature, and extracellular matrix elasticity loss.
(Fernando et al., 1991).
[0026] Orthotic interventions for high pressures on the foot are
well known and have been developed to redistribute the pressure
over more of the foot or to areas of the foot that can take the
pressure better. The most common preventative method using pressure
is the use of specialized insoles in order to redistribute force.
These insoles are often made of three materials placed from lowest
durometer to highest durometer. (Van De Weg, Van Der Windt, &
Vahl, 2008). This allows for cushioning at the skin interface while
giving the foot support to prevent bottoming out of the insole and
maintaining good biomechanical position of the foot. Insoles are
often customized to patients who have greater risk of ulceration.
These custom inserts position indents of lower durometer material
under the highest pressure areas of the foot, often under the first
and second MTP joints. (Actis et al., 2008). Clinicians can often
tell where these high-pressure areas are due to the presence of
calluses and skin reddening under these high pressure areas. (Menz
et al., 2007).
[0027] The most common method of pressure relief is the excavation
of higher durometer material from underneath high-pressure areas
and the area filled instead with lower durometer material such as
PORON. (Actis et al., 2008). It has been shown that these
modifications can reduce pressure by 16-48% under these areas.
(Actis et al., 2008). By properly placing these pressure reducing
areas, peak pressure on a foot can be decreased by an order of
magnitude that can make the difference between whether or not a
patient will develop a DFU. (Actis et al., 2008). Failing to place
these pressure-reducing areas can lead to increased pressure at the
areas of the foot that need relief. Placement and design of these
insoles can be done through the use of either foam molds or
scanning devices and software.
[0028] It is important to note that custom inserts are only one
component of preventative methods. The need for accommodative
footwear that is properly sized and modified for the patient is
paramount to preventing ulcers at locations away from the plantar
surface of the foot. While extra depth footwear is commonly used in
diabetic populations, which allows for extra room in the toe box,
which prevents rubbing and pressure on the toes, patients with
deformation that would make the use of these off the shelf footwear
inappropriate require custom footwear fitted to their feet. Another
modification that can be done in order to prevent high pressures at
the MTPs caused by decreased mobility of the joints of the foot are
rocker bottom modifications. (Schaff & Cavanagh, 1990) This
modification is based on the idea that without the proper motion at
the joints of the foot, pressure will move from the heel to the
forefoot. Rocker bottoms allow for a more natural rollover occurs
during gait causing these unnatural pressures to be dissipated.
[0029] Considering these modifications and orthotics used, there is
still a fairly significant failure to prevent ulcers using these
devices. Over time it is 15% likely that a diabetic patient will
develop an ulcer that can become life threatening. (Mroczek, 2008)
Considering this, inspiration must come from similar fields that
can lend their knowledge base. One such concept taken from pressure
ulcer research is the use of temperature in order to prevent
ulceration from occurring. Through the use of local cooling,
pressure has been found to be somewhat negated when a lower
temperature has been reached in the tissue. As presented before,
the mechanisms of prevention through cooling aim at affecting the
tissue through both metabolic and biomechanical changes. The tissue
changes that occur in diabetes cause some of these treatments to be
less effective while others become more needed. The two big
problems diabetics face that can be affected by cooling consist of
metabolic changes of tissue and temperature regulation.
[0030] Metabolic issues especially occur in the diabetic population
due to the changes to glucose regulation and levels in the body.
(Mayo Clinic Staff, 2014b) Decreasing temperature has been shown to
decrease the metabolic rate. (Kokate et al., 1995) Using this
concept, cooling tissue that has a decreased blood supply can be
related to cooling the body to reduce necrosis of tissue during
surgeries. (Kokate et al., 1995) Temperature regulation has been
found to be a major issue for diabetics due to neurological changes
that occur due to diabetic neuropathy. One of the most obvious
effects of lack of temperature control is the lack of sweating at
increased temperature.
[0031] Thus, there exists a need for a TCF that adds cooling
functionality to a pressure-reducing surface of the foot bed.
SUMMARY
[0032] One aspect of a preferred embodiment of the present
disclosure comprises a footwear product with an integrated active
temperature control system comprising: an upper; a sole comprising
an insole comprising one or more thermo-conductive inserts or
plugs; a midsole disposed between the insole and an outsole;
wherein the midsole comprises one or more cooling elements selected
from the group consisting of: an air flow cooling element, a liquid
cooling element, a thermoelectric cooling element; and one or more
heat sinks disposed in the midsole, outsole or between the midsole
and outsole.
[0033] In another aspect of a preferred footwear product of the
present disclosure, the thermo-conductive inserts or plugs comprise
one or more materials selected from the group consisting of a gel,
an open-cell polyurethane foam, a closed-cell expanded rubber, a
low friction interface material, and a polyethylene thermoplastic
foam.
[0034] In yet another aspect of a preferred footwear product of the
present disclosure, a separate one of the one or more cooling
elements is disposed adjacent to or underneath each of the one or
more the thermo-conductive inserts or plugs.
[0035] In another aspect of a preferred footwear product of the
present disclosure, each of the one or more cooling elements
comprises an active solid-state electrical device.
[0036] In an additional aspect of a preferred footwear product of
the present disclosure, each of the one or more cooling elements
comprises a thermo-electric cooling element having an active
solid-state electrical device that operates on the Peltier
effect.
[0037] In another aspect, a preferred footwear product of the
present disclosure further comprises a power source for the one or
more cooling elements.
[0038] In another aspect of a preferred footwear product of the
present disclosure, the power source comprises rechargeable
batteries that may be recharged when in use and/or when not in
use.
[0039] In another aspect, a preferred footwear product of the
present disclosure further comprises a control system or a closed
loop passive control system to control the amount of heat being
removed from the footwear product.
[0040] In yet another aspect of a preferred footwear product of the
present disclosure, the one or more thermo-conductive inserts or
plugs also provide cushioning to control pressure and/or shear and
are each disposed in a portion of the insole contacting a
high-pressure area or other area of the plantar surface of a foot
disposed in the footwear product that normally experiences tissue
breakdown, such as the first metatarsal or heel.
[0041] In another aspect, a preferred footwear product of the
present disclosure further comprises a power source for the one or
more heat sinks.
[0042] In yet another aspect of a preferred footwear product of the
present disclosure, the one or more heat sinks are passive or
body-powered.
[0043] In yet another aspect of a preferred footwear product of the
present disclosure, each of the one or more heat sinks employs an
air movement system that uses convection to move heat from each
heat sink into the environment outside of the footwear product.
[0044] In a further aspect of a preferred footwear product of the
present disclosure, each of the one or more heat sinks employs the
loading and/or unloading of the sole during gait to create airflow
through or across each heat sink to move heat from each heat sink
into the environment outside of the footwear product.
[0045] In another aspect, a preferred footwear product of the
present disclosure further comprises temperature and/or pressure
sensor(s) associated with each of the one or more thermo-conductive
inserts or plugs.
[0046] In yet another aspect, a preferred footwear product of the
present disclosure further comprises a control system or CPU to
control the amount of heat being removed from the footwear product;
wherein the control system or CPU has an input for setting the
temperature to be maintained or to not be exceeded at each location
of the one or more thermo-conductive inserts or plugs.
[0047] In a further aspect of a preferred footwear product of the
present disclosure, the input is disposed inside or outside of the
footwear product and/or is operatively connected wirelessly or by
wire to the control system.
[0048] In another aspect of a preferred footwear product of the
present disclosure, the integrated active temperature control
system is activated upon exceeding a preset pressure on one or more
of the pressure sensors.
[0049] In a further aspect of a preferred footwear product of the
present disclosure, each of the one or more heat sinks comprises a
metal component and/or a thermal-conductive foam component.
[0050] In another aspect of a preferred footwear product of the
present disclosure, a single heat sink comprises one or more metal
components and/or a thermal-conductive foam components and wherein
the single heat sink directly contacts each of the one or more
thermo-electric cooling elements.
[0051] Another aspect of a preferred embodiment of the present
disclosure comprises a kit for retrofitting a footwear product to
include an integrated active temperature control system, wherein
the kit comprises one or more of the following items: a plug,
having an upper surface comprising a low friction interface
material and comprising a thermally conductive material, wherein
the plug is for placement in an opening in an existing insole, a
heat sink and cooling device for placement in the midsole and/or
outer sole of the footwear product and a thermal paste or adhesive
for connecting the thermal conductive material of the plug to the
cooling device and/or heat sink.
[0052] In another aspect of a preferred kit of the present
disclosure, the cooling device is selected from the group
consisting of: an air flow cooling element, a liquid cooling
element, a thermoelectric cooling element.
[0053] In a further aspect of a preferred kit of the present
disclosure, the plug comprises one or more materials selected from
the group consisting of: a gel, an open-cell polyurethane foam, a
closed-cell expanded rubber, a cushioning material and a
polyethylene thermoplastic foam.
[0054] In another aspect of a of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] The present disclosure is illustrated by way of example and
not limitation in the figures of the accompanying drawings, in
which:
[0056] FIG. 1 shows a traditional extra depth footwear design;
[0057] FIG. 2 is a cross-sectional view of a preferred embodiment
of a footwear product with an integrated active temperature control
system according to the present disclosure;
[0058] FIG. 3 is a cross-sectional view with heat flow diagram of a
preferred embodiment of a footwear product with an integrated
active temperature control system according to the present
disclosure; and
[0059] FIG. 4 is a diagram of a control circuit for a preferred
embodiment of a footwear product with an integrated active
temperature control system according to the present disclosure.
DETAILED DESCRIPTION
[0060] In the following detailed description, reference is made to
the accompanying examples and figures that form a part hereof, and
in which is shown by way of illustration specific embodiments in
which the inventive subject matter may be practiced. These
embodiments are described in sufficient detail to enable those
skilled in the art to practice them, and it is to be understood
that other embodiments may be utilized and that structural,
logical, and electrical changes may be made without departing from
the scope of the inventive subject matter. Such embodiments of the
inventive subject matter may be referred to, individually and/or
collectively, herein by the term "disclosure" merely for
convenience and without intending to voluntarily limit the scope of
this application to any single disclosure or inventive concept if
more than one is in fact disclosed.
[0061] The following description is, therefore, not to be taken in
a limited sense, and the scope of this disclosure is defined by the
appended claims.
[0062] A preferred embodiment of a temperature control therapeutic
footwear (TCF) of the present disclosure comprises one or more
coolers 35, heat sink 32, insole material 25 and, in various
embodiments, a plug 40 and control circuit (as shown in FIG.
4).
[0063] Preferably, cooler 35 will be a thermoelectric cooler which
uses the Peltier effect in order to transform a voltage
differential into a temperature differential. Thermoelectric
coolers are relatively thin, light yet durable, are able to be
controlled accurately, operate over the desired temperature range,
and durability. Each thermoelectric cooler 35 is mated to a heat
sink 32 to manage any bleed through of heat.
[0064] Preferably, heat sink 32 will act to effect adequate removal
of heat from the thermoelectric cooler 35, release of heat into the
external environment, and be of minimal weight. Heat sink 32
preferably will not affect the gait of the wearer and be durable.
Preferably, heat sink 32 will be made of aluminum or other suitable
metal or material. The TCF 20 of the present disclosure preferably
has an open air system into the sole 23 which comprises insole 25,
midsole 26 and outsole 27 to allow for good airflow and convection
to occur at the heat sink 32. Thermoelectric cooler 35 will
preferably be attached to heat sink 32 using thermo-conductive
adhesive that is commonly used with CPUs and heat sinks in high end
computers.
[0065] Material for insole 25 and plug 40 are an integral portion
of this design because they are in direct contact with the wearer.
Plug material preferably is thermo-conductive while having a low
durometer in order to accommodate the increased pressure under the
high pressure areas, such as the MTPs or under deformities.
Additionally, insole material should be machinable and easy to
implant in order for practitioners or manufacturers to be able to
custom place the devices for each wearer.
[0066] Preferably, the control circuit of the TCF 20 is
programmable to allow for targeted temperature, as well as to
provide energy conservation. A preferred control circuit of the TCF
20 is easily calibrated in order to account for weight, resting
body temperature, other disease considerations that may affect the
pressure or temperature setting for TCF 20. The control circuit of
TCF 20 also preferably is small and requires minimal energy to
operate.
[0067] Preferably, TCF 20 of the present disclosure is customizable
for each individual wearer. Preferably, the TCF 20 is customizable
via on site tools and may also comprise a heat sink incorporated
into the outer sole 27 to effectively dissipate heat from TCF
20.
[0068] As seen in FIGS. 2 and 3, the foot is in contact with a
thermo-conductive plug 40 that is placed under a clinician-selected
location within TCF 20. Plug 40 preferably comprises an upper
surface 33 comprising a low friction interface material
manufactured with polytetrafluoroethylene (PTFE) film, such as
ShearBan.RTM., to protect the wearer's skin from damaging friction
& shear trauma. Additionally, plug 40 comprises a cushioning
pad 28 (preferably of a gel) and cooler 35 and heat sink 32 may
also be incorporated into plug 40 in various preferred embodiments
of TCF 20. Alternatively, heat sink 32 is disposed in or part of
outer sole 27. TCF 20 moves the heat away from the foot towards
outer sole 27 allowing for therapeutic temperature control at the
high-pressure areas of the foot. The arrows in FIG. 3 show a
preferred heat flow diagram accomplished by TCF 20.
[0069] The thermo-conductive plug 40 preferably will consist of an
easily machinable material, such as EVA, along with good heat
conductors such as thermo-conductive gels. This will allow for the
plug to be placed and fitted into a specific area of the foot,
while keeping the conductive qualities that are needed. The
placement of the plug 40 will be conducted using the current method
of excavating the higher durometer material from the bottom of the
material and then adhering the new lower durometer material to fill
the location. This method allows for a customizable cooling plug 40
that can be specifically placed by the practitioner without much
difficulty. By designing the heat sink 32 with the goal of
adjustability of the location of plug 40, a variety of sizes or
adjustability of the heat sink 32 can allow for relatively easy
customization.
[0070] TCF 20 preferably comprises diabetic footwear technology
that prevents ischemic damage and subsequent diabetic foot ulcer
development. Maintaining skin temperature at lower levels where
high-pressure occludes blood flow minimizes ischemic damage. TCF 20
preferably maintains skin temperature at select locations of the
foot at pre-activity levels during activity and after extended
use.
[0071] Insole. The whole insole 25 is preferably made of thermal
insulate materials, and thermo conductive gel pads 28 are
preferably placed at the high-pressure areas, e.g., first
metatarsal, and heel. By using controlled localized cooling it is
possible to give therapeutic cooling to the needed areas while not
affecting the rest of the foot.
[0072] Midsole. Cooling elements 35 such as phase change cooling
(cooling packs), passive cooling (heat sink only), air flow cooling
(fans, etc.), liquid cooling, Peltier (thermoelectric coolers),
heat pipe systems or the like will be placed at the same locations
as the gel pads 28 (and may preferably comprise part of plug 40) to
maintain the temperature. Preferably, the thermoelectric cooling
elements 35 are active solid-state electrical modules that operate
on the Peltier effect, which is a phenomenon whereby the passage of
an electrical current through a junction consisting of two
dissimilar metals results in a cooling effect. Preferably, cooling
elements 35 use rechargeable batteries as a power source whereby
the user would recharge TCF 20 when not in use. Preferably, a
closed loop passive control system will be used to control the
amount of heat being removed from the plantar surface of the foot
by TCF 20. This will act as a safety and energy conservation
mechanism.
[0073] Outsole. A heat sink 32 preferably will be used to move the
heat away from the one or more thermoelectric coolers 35.
Preferably, heat sinks 32 will either be a passive or a
body-powered device. In a preferred embodiment, heat sink 32
comprises a gait-powered air movement system that would use
convection to move heat from the heat sink 32 into the environment
outside of TCF 20. Such a heat sink 32 would use the loading and
unloading of the footwear during gait to create airflow through the
heat sink 32.
[0074] The present disclosure also contemplates a kit for
retrofitting a footwear product, such as a diabetic footwear
product, to include an integrated active temperature control
system, wherein the kit comprises one or more of the following
items: a soft material plug 40 having an upper surface 33
comprising a low friction interface material manufactured with
polytetrafluoroethylene (PTFE) film and a thermal conductive core
28 that can be placed into an existing insole, a heat sink 32 and
cooling device 35 that will preferably be placed inside the outer
sole 27 of TCF 20 and will be connected to the thermal conductive
material 28 via thermal paste or adhesive.
[0075] It should be understood that while this disclosure has been
described herein in terms of specific, preferred embodiments set
forth in detail, such embodiments are presented by way of
illustration of the general principles of the disclosure, and the
disclosure is not necessarily limited thereto. Certain
modifications and variations in any given material, process step or
chemical formula will be readily apparent to those skilled in the
art without departing from the true spirit and scope of the present
disclosure, and all such modifications and variations should be
considered within the scope of the claims that follow.
* * * * *