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Home Monitoring of Foot Skin Temperatures to Prevent Ulceration

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To evaluate the effectiveness of at-home infrared temperature monitoring as a preventative tool in individuals at high risk for diabetes-related lower-extremity ulceration and amputation. Eighty-five patients who fit diabetic foot risk category 2 or 3 (neuropathy and foot deformity or previous history of ulceration or partial foot amputation) were randomized into a standard therapy group (n = 41) or an enhanced therapy group (n = 44). Standard therapy consisted of therapeutic footwear, diabetic foot education, and regular foot evaluation by a podiatrist. Enhanced therapy included the addition of a handheld infrared skin thermometer to measure temperatures on the sole of the foot in the morning and evening. Elevated temperatures (>4 degrees F compared with the opposite foot) were considered to be "at risk" of ulceration due to inflammation at the site of measurement. When foot temperatures were elevated, subjects were instructed to reduce their activity and contact the study nurse. Study subjects were followed for 6 months. The enhanced therapy group had significantly fewer diabetic foot complications (enhanced therapy group 2% vs. standard therapy group 20%, P = 0.01, odds ratio 10.3, 95% CI 1.2-85.3). There were seven ulcers and two Charcot fractures among standard therapy patients and one ulcer in the enhanced therapy group. These results suggest that at-home patient self-monitoring with daily foot temperatures may be an effective adjunctive tool to prevent foot complications in individuals at high risk for lower-extremity ulceration and amputation.
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Home Monitoring of Foot Skin
Temperatures to Prevent Ulceration
LAWRENCE A. LAVERY,
DPM, MPH
1
KEVIN R. HIGGINS,
DPM
2
DAN R. LANCTOT,
BS
2
GEORGE P. CONSTANTINIDES,
MS
2
RUBEN G. ZAMORANO,
MSW, MPH
2
DAVID G. ARMSTRONG,
DPM
3
KYRIACOS A. ATHANASIOU,
PHD, PE
4
C. MAULI AGRAWAL,
PHD, PE
1,5
OBJECTIVE To evaluate the effectiveness of at-home infrared temperature monitoring as
a preventative tool in individuals at high risk for diabetes-related lower-extremity ulceration and
amputation.
RESEARCH DESIGN AND METHODS Eighty-five patients who fit diabetic foot risk
category 2 or 3 (neuropathy and foot deformity or previous history of ulceration or partial foot
amputation) were randomized into a standard therapy group (n 41) or an enhanced therapy
group (n 44). Standard therapy consisted of therapeutic footwear, diabetic foot education, and
regular foot evaluation by a podiatrist. Enhanced therapy included the addition of a handheld
infrared skin thermometer to measure temperatures on the sole of the foot in the morning and
evening. Elevated temperatures (4°F compared with the opposite foot) were considered to be
“at risk” of ulceration due to inflammation at the site of measurement. When foot temperatures
were elevated, subjects were instructed to reduce their activity and contact the study nurse. Study
subjects were followed for 6 months.
RESULTS The enhanced therapy group had significantly fewer diabetic foot complications
(enhanced therapy group 2% vs. standard therapy group 20%, P 0.01, odds ratio 10.3, 95%
CI 1.2–85.3). There were seven ulcers and two Charcot fractures among standard therapy
patients and one ulcer in the enhanced therapy group.
CONCLUSIONS These results suggest that at-home patient self-monitoring with daily
foot temperatures may be an effective adjunctive tool to prevent foot complications in individuals
at high risk for lower-extremity ulceration and amputation.
Diabetes Care 27:2642–2647, 2004
F
oot ulcers are one of the most com-
mon precursors to diabetes-related
amputations (1,2). Other factors that
have been associated with amputation,
such as infection, faulty wound healing,
and ischemia, usually do not cause tissue
loss or amputation in the absence of a
wound. Therefore, ulcer prevention is
one of the foci of any amputation preven-
tion program.
One of the most common mecha-
nisms in the development of neuropathic
foot ulcerations involves a cumulative ef-
fect of unrecognized repetitive trauma at
pressure points on the sole of the foot over
the course of several days (3–5). The stan-
dard approach to prevent ulceration is to
provide padded insoles and protective
shoes, educate the patient and their fam-
ily, and provide regular foot inspection by
the patient’s primary care physician or
podiatrist.
Except for traumatic wounds, areas
that are likely to ulcerate have been asso-
ciated with increased local skin tempera-
tures due to inflammation and enzymatic
autolysis of tissue (6 8). Identifying areas
of injury by the presence of inflammation
would then allow patients or health care
providers to take action to decrease the
inflammation before a wound develops.
Our rationale for evaluating skin temper-
atures involves the search for a quantifi-
able measurement of inflammation that
can be used to identify pathologic pro-
cesses before they result in ulcers. Inflam-
mation is one of the earliest signs of foot
ulceration. It is characterized by five car-
dinal signs: redness, pain, swelling, loss of
function, and heat. Many of these signs
are difficult to assess objectively. In the
neuropathic extremity, pain and distur-
bance of function may be absent because
of neuropathy and thus are poor indica-
tors of inflammation. In addition, swell-
ing and redness are difficult to objectively
grade even among experienced clinicians.
Most lay people will not be able to under-
stand or accurately evaluate these subtle
parameters. However, temperature mea-
surements can be easily performed by pa-
tients or their spouses and provide
quantitative information that has been
shown (6,9 –11) to be predictive of im-
pending ulceration.
The objectives of the study were to
evaluate the effectiveness of a novel infrared
temperature instrument to improve clinical
outcomes and functional status in diabetic
patients at high risk for foot complications.
The infrared skin temperature device was
used to provide objective information to pa-
tients so they would have an “early warning
sign” of inflammation and tissue injury be-
cause their innate ability to perceive pain
and protect their feet from tissue injury was
blocked by severe diabetic peripheral sen-
sory neuropathy.
●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●
From the
1
College of Medicine, Texas A&M Health Science Center, Scott and White Hospital, Temple, Texas;
2
Xilas Medical, San Antonio, Texas; the
3
Dr. William M. Scholl College of Podiatric Medicine, Rosalind
Franklin University of Medicine, Chicago, Illinois; the
4
Department of Bioengineering, Rice University,
Houston, Texas; and the
5
Department of Biomedical Engineering, The University of Texas, San Antonio,
Texas.
Address correspondence and reprint requests to Lawrence A. Lavery, 703 Highland Spring Ln., George-
town, TX 78628. E-mail: llavery@swmail.sw.org.
Received for publication 20 May 2004 and accepted in revised form 6 August 2004.
L.A.L., D.G.A., and K.A.A. are paid consultants for, serve on an advisory board for, and hold stock in Xilas
Medical.
Abbreviations: VPT, vibratory perception threshold.
A table elsewhere in this issue shows conventional and Syste`me International (SI) units and conversion
factors for many substances.
© 2004 by the American Diabetes Association.
Pathophysiology/Complications
ORIGINAL ARTICLE
2642 DIABETES CARE, VOLUME 27, NUMBER 11, NOVEMBER 2004
RESEARCH DESIGN AND
METHODS This study was a single-
blinded, randomized clinical trial of 85
patients assigned to either a standard
therapy group or an enhanced therapy
group. Subjects were recruited from the
high-risk diabetic foot clinics at the Uni-
versity of Texas Health Science Center at
San Antonio. Study subjects were evalu-
ated for 6 months. During the course of
study, the treating physician was blinded
as to whether the patient belonged to ei-
ther the standard therapy or enhanced
therapy group.
Both groups received standard care
consisting of therapeutic footwear, dia-
betic foot education, and foot evaluation
by a podiatrist every 10 –12 weeks. In ad-
dition to the standard elements of diabetic
foot care, the enhanced therapy group
also used a handheld infrared skin ther-
mometer (TempTouch; Xilas Medical,
San Antonio, TX) to measure tempera-
tures on the sole of the foot in the morn-
ing and evening. Fundamentally, this
methodology used skin temperature mea-
surements to forewarn the patient of im-
pending inflammation and ulceration. Six
predetermined sites were measured and
recorded in a log book on each foot. The
sites tested include first, third, and fifth
metatarsal head, great toe, central mid-
foot, and heel. If a toe or toe and metatar-
sal had been previously amputated, an
adjacent anatomic area was measured.
For instance, if the great toe had been am-
putated, the second toe was used as a tem-
perature assessment site. If a site had
callus, it was still used as a temperature
assessment site.
If there was a temperature difference
4°F (4.0°F 2.2°C) between the left
and right corresponding sites, the patients
were advised to contact a nurse case man-
ager and to significantly reduce the num-
ber of steps taken in the following days or
until the temperature differences fell 4°.
The clinical outcomes that were evaluated
were incident foot ulcers, infections,
Charcot fractures, and amputations.
Patients who were enrolled in the
study met a high-risk profile for develop-
ing diabetic foot ulcerations. We defined
high-risk patients as adult patients with
diabetes with a history of foot ulceration
or lower-extremity amputation or pa-
tients with peripheral sensory neuropathy
with loss of protective sensation, with a
foot deformity such as hallux valgus or
claw toes. These criteria are based on pre-
viously identified risk factors for foot ul-
cerations and amputations (12,13).
Inclusion criteria included diagnosis
of diabetes by World Health Organization
criteria (14), ability to provide informed
consent, age 18 80 years, and risk group
2 or 3 using the diabetic foot risk classifi-
cation system as specified by the Interna-
Table 1—Patient characteristics and clinical outcomes
Standard therapy Enhanced therapy
Patient population 44 41
Age (years) 54.8 9.6 55.0 9.3
Sex (% men) 52.3 48.8
Duration of diabetes (years) 12.7 10.0 14.8 11.5
Risk category 2 26 (59) 24 (59)
Risk category 3 18 (41) 17 (41)
History of amputation 1 (fifth toe amputation) 1 (second toe amputation)
Risk category mean 2.41 0.50 2.41 0.50
VPT (left foot) 33.8 10.4 35.9 9.1
VPT (right foot) 35.9 11.3 36.5 8.6
Elective/voluntary dropouts
from the study
43
Outcomes
Foot ulceration 7* 1
Charcot fracture 2 0
Total 9* 1
Data are means SD or n (%). *P 0.05.
Table 2—SF-36 scores
Pre- versus posttesting
Standard
therapy
Enhanced
therapy
Physical functioning
Pre 44.7 30.6 46.7 32.1
Post 44.3 36.5 45.3 36.4
Role physical
Pre 38.4 41.7 37.2 42.7
Post 36.3 41.74 39.0 44.1
Bodily pain
Pre 62.1 24.7 57.8 26.2
Post 52.9 32.1 53.2 33.3
General health
Pre 49.9 21.3 48.1 21.2
Post 42.7 30.2 42.0 28.5
Vitality
Pre 51.2 22.2 49.2 22.4
Post 51.1 28.9 49.0 30.1
Social functioning
Pre 64.8 26.5 64.8 26.3
Post 60.5 35.2 60.8 34.6
Role emotional
Pre 52.0 49.1 49.6 50.0
Post 47.0 43.3 52.7 45.0
Mental health
Pre 67.8 22.4 67.3 23.4
Post 64.5 32.6 65.7 30.7
Data are means SD. There was no significant difference in any of the measurements of the SF-36 when
pre- and posttherapy measurements were compared.
Lavery and Associates
DIABETES CARE, VOLUME 27, NUMBER 11, NOVEMBER 2004 2643
tional Working Group on the Diabetic
Foot (13). Exclusion criteria included pa-
tients with open ulcers or open amputa-
tion sites, active Charcot arthropathy,
peripheral vascular disease, active foot in-
fection, dementia, impaired cognitive
function, history of drug or alcohol abuse
within 1 year of the study, or other con-
ditions based on the principal investiga-
tor’s clinical judgment.
Neurologic assessment consisted of
testing vibratory perception threshold
(VPT) (15,16). For the purpose of this
study, we assessed VPT at the distal pulp
of the great toe using the Xilas VPT meter
(Xilas Medical, San Antonio, TX). The
presence of sensory neuropathy was de-
fined as VPT 25 V. The vascular assess-
ment consisted of palpation of dorsalis
pedis and posterior tibial arteries. If one
or both arterial pulses were not palpable,
the subject was excluded.
The Short-Form Health Survey (SF-
36) (17) was used at the beginning and
end of the study to evaluate functional
impairment (18).
We used an ANOVA to evaluate all
continuous variables between treatment
groups. Dichotomous variables were eval-
uated with a Fisher’s exact test with odds
ratio and 95% CI. For all analyses we used
an of 0.05. Analysis was conducted on
an intent-to-treat basis.
RESULTS
Foot complications
There were no significant differences in
age, duration of diabetes, severity of neu-
ropathy measured by VPT, or diabetic
foot risk category among patients as-
signed to the standard therapy and en-
hanced therapy groups (Table 1). The
most striking result of the study was the
disparity in the number of foot complica-
tions between the two groups. Patients in
the enhanced therapy group exhibited
significantly fewer diabetic foot complica-
tions (Table 1). There were nine (20%)
foot complications in the 44 patients in
the standard therapy group and one (2%)
complication in the 41 patients in the
group that used home infrared tempera-
ture monitoring (
2
6.63, P 0.01).
Patients in the standard therapy group
were 10.3 times more likely to develop a
foot complication compared with patients
in the enhanced therapy group (95% CI
1.2–85.3). In the standard therapy
group, there were seven ulcers and two
Charcot fractures. Two of the patients de-
veloped infections and required local foot
amputations. In the enhanced therapy
group, one patient developed an ulcer.
No infections, amputations, or Charcot
fractures were identified in the enhanced
therapy group. There were three patients
in the standard therapy group who volun-
tarily dropped out of the study, and four
patients in the enhanced therapy group
dropped out of the study.
Quality of life
We used the SF-36 to evaluate functional
status at the beginning and end of the
study (Table 2). There were no statistical
differences in the SF-36 scores (total or
subcategory scores) either between
Figure 1—This graph shows daily temperatures taken under the first metatarsal of patient 3. Patient 3 was a 56-year-old man with a 7-year history
of diabetes and a history of amputation. This patient maintained a consistent temperature pattern throughout the monitoring period and did not
experience any foot complication. Temperature differences on the y-axis were determined by comparing temperatures measured under the first
metatarsal head on the right and left feet. Measurements that are above the 4°F “boundary” limit at the top of the graph represent higher temperatures
on the right foot, and measurements beyond the lower “boundary” represent higher temperatures on the left foot.
Foot ulcers and temperature monitoring
2644 DIABETES CARE, VOLUME 27, NUMBER 11, NOVEMBER 2004
groups (unpaired t test) or, in the pre- and
poststudy evaluations, within groups
(paired t test).
Two examples of temperature varia-
tions are provided in Figs. 1 and 2. Figure
1 shows the foot temperature profile for a
patient who suffered no complications
during the study. The temperature differ-
ence did occasionally exceed the 4°F
range, but did not stay at this level. Figure
2 shows the temperature profile for a 48-
year-old woman with diabetes for 12
years, a history of severe sensory neurop-
athy, and a previous ulceration under the
first metatarsal head. She had several ep-
isodes of temperatures above the 4°F
range. She failed to call the study nurse as
instructed when her temperatures spiked
throughout the study. On day 138, she
was seen in clinic, and a superficial
wound under the first metatarsal head
was identified. The patient failed to con-
tact the health care provider upon record-
ing a series of 4°F temperature
differences on 21 consecutive days just
before ulceration. This patient was the
only subject in the enhanced therapy
group who developed a wound.
CONCLUSIONS The results of
this pilot study suggest that home moni-
toring with daily foot temperatures could
be an effective adjunctive modality to pre-
vent foot complications. The clinical out-
comes in the enhanced therapy group
were significantly better than those in the
standard therapy group. Patients were
able to use the device and either modify
their activity or contact the study nurse
for advice or to schedule clinical evalua-
tion. Previous studies (17,19 –22) report
ulcer recurrence in 1 year of 26 40% in
subjects who use therapeutic footwear
following ulcer healing. In our study,
16% of patients in the standard therapy
group and 2.4% of patients in the en-
hanced therapy group reulcerated (16%
ulcers and 4.5% Charcot fractures in stan-
dard therapy). The annualized rates ob-
served in our standard therapy group are
similar to reulceration rates in other stud-
ies. Patients in the home temperature-
monitoring group had a very low rate of
foot complications compared with our
standard therapy group and reports using
similar prevention practices.
The lower incidence of Charcot ar-
thropathy in subjects with home monitor-
ing was a logical clinical outcome but not
an a priori study objective. We used a
standard clinical approach to diagnose
Charcot arthropathy. If patients had uni-
lateral swelling, deformity, increased
temperature, or any other concerns, they
had access to study podiatrists for imme-
diate clinical evaluation, radiographic as-
sessment, and additional diagnostic
imaging as deemed appropriate by the
treating physician. We believe that the
subjects using the home temperature-
monitoring device had a lower threshold
for a physician to diagnose Charcot be-
cause of the study’s built-in referral pat-
tern for elevated temperatures. We would
have expected more subtle cases of Char-
cot’s arthropathy to be diagnosed in the
home monitoring group. Temperature
measurements have been reported
(23,24) as an assessment tool to diagnose
and monitor treatment of Charcot’s ar-
thropathy. Because most patients at risk
for ulceration are also at risk for Charcot,
a longer study in the future may help pro-
vide more information on temperature as-
Figure 2—The graph shows daily temperature measurements taken under the first metatarsal head of a study patient who developed a wound at this
site.
Lavery and Associates
DIABETES CARE, VOLUME 27, NUMBER 11, NOVEMBER 2004 2645
sessment to prevent fracture as well as
ulceration.
Even among educated, well-
informed, and highly motivated pa-
tients, there is a high rate of recidivism
of diabetic foot complications. These
patients almost uniformly have severe
sensory loss. Often they are obese, have
limited mobility of the hip and knee, or
are visually impaired. These factors
make self-inspection and identification
of early signs of foot disease difficult.
For instance, in an earlier study (3), we
identified that 15% of diabetic patients
with foot ulceration were legally blind,
and 54% of these patients did not have
adequate visually acuity and the ability
to position their extremity to view the
foot for self-care. In addition, visual
cues probably occur late in the disease
process. They are often subtle, and be-
cause pain is usually our primary trigger
to provide self-care or seek professional
care, a patient’s ability to take action to
avoid neuropathic foot ulceration is
poor. As part of patient education, both
treatment groups were instructed to in-
spect their feet on a daily basis. Most
likely by the time there were visual signs
of a foot problem, implementing pre-
vention was too late. The simple home
monitoring device used in this study
allowed high-risk patients a self-
assessment tool they could easily use
and from which to obtain actionable
information.
There are several issues that have
been raised from this initial study that
need further investigation and evaluation.
Firstly, the outcomes may be a result of
increased vigilance and enhanced foot in-
spection in the subjects who used the
temperature device. Subsequent studies
in this area should consider randomizing
to a third patient cohort, in whom some
form of active screening and reporting
mechanism (such as a daily log form)
would be used. Also future studies may
consider the efficacy of once-daily tem-
perature monitoring instead of the twice-
daily protocol used in this study.
Secondly, it is entirely possible that simi-
lar outcomes may not be enjoyed over a
larger time frame. Subsequent studies
should consider extending the follow-up
period. It is possible that the subjects in
the enhanced therapy group participated
in their foot care more enthusiastically be-
cause they were using an inspection tool.
It was not feasible to blind the study sub-
jects or give them a sham temperature de-
vice. We felt that this might give them a
false sense of safety and might in fact in-
crease the risk of foot complications in a
sham treatment arm. Finally, even if a mo-
dality such as thermometry proves able to
serve as an early warning system for de-
velopment of diabetic foot wounds, fu-
ture studies should also consider whether
this intervention is cost-effective over a
wide-ranging population.
In summary, this pilot study suggests
that early identification of preulcerative
inflammation through the use of personal
thermometers may be an effective means
to further reduce risk for diabetic foot ul-
ceration. We look forward to further stud-
ies in the literature that may either
confirm or refute this suggestion. If posi-
tive, we believe that ultimately, thermom-
eters may be used to allow patients to dose
their activity (by checking their skin tem-
peratures) just as many dose their insulin
by checking their blood glucose.
Acknowledgments This study (1R43D
K54559-01) was funded by the National Insti-
tutes of Health/National Institute of Diabetes
and Digestive and Kidney Diseases (NIDDK)
under the Small Business Innovation Research
(SBIR) program.
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Lavery and Associates
DIABETES CARE, VOLUME 27, NUMBER 11, NOVEMBER 2004 2647
... Then, following a review of the full papers of the remaining hits, six were rejected for the following reasons: Focusing on treatment, not a research paper, and not focusing on the primary outcome [23][24][25][26][27][28] (Table 1). Thus, eight studies were finally included and form the basis of this review [18,[29][30][31][32][33][34][35][36]. ...
... The geographical location of the studies varied between the Netherlands [32], the United Kingdom [29,31,34,36], and the United States of America [18,30,33]. ...
... Out of the 8 studies, 4 of which were at various diabetic foot/podiatry clinics [31,33,34,36]. There was one study done by the multidisciplinary tertiary care diabetic foot center [29]. ...
... Some of these signs are difficult to assess objectively. In a neuropathic extremity, pain and disturbance of function may be absent because of neuropathy, and thus, these signs are poor indicators of oncoming inflammation [11]. In addition, swelling and redness are difficult to grade precisely even for experienced clinicians. ...
... However, there is no standard distribution for the skin-surface temperature of a healthy foot because that temperature can be affected by many factors, such as ambient and internal thermal conditions, age, sex, weight, etc. One way to eliminate this variability is to compare the thermal skin distributions of both feet on the same subject [10,11]. This comparison, called asymmetry/ symmetry analysis, has been widely used by researchers and clinicians to identify pathological conditions in the brain, breast, and other body parts that present similar symmetric characteristics. ...
Preprint
Asymmetry analysis based on the overlapping of thermal images proved able to detect inflammation and, predict foot ulceration. This technique involves three main steps: segmentation, geometric transformation, and overlapping. However, the overlapping technique, which consists of subtracting the intensity levels of the right foot from those of the left foot, can also detect false abnormal areas if the projections of the left and right feet are not the same. In this paper, we present an alternative technique to asymmetry analysis-based overlapping. The proposed technique, scalable scanning, allows for an effective comparison even if the shapes and sizes of the feet projections appear differently in the image. The tested results show that asymmetry analysis- based scalable scanning provides fewer false abnormal areas than does asymmetry analysis -based overlapping.
... Research supports that an increase in foot temperature beyond a specific threshold will suggest inflammation of the foot [20]. A temperature difference of more than 4 • F between a patient's feet is a potential indicator of developing a foot ulcer [21]. ...
... To acquire an accurate temperature value, the thermistor resistance and the lookup table provided by the datasheet were used, and then linear interpolation was conducted on the resistance value less than and greater than the thermistor resistance. The smart compression sock will notify patients if the temperature difference between the patient's two feet is greater than 4 • F, as this difference signifies that the patient has the potential to develop a foot ulcer [21]. ...
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The prevention of diabetic foot ulcers remains a critical challenge. This study evaluates a smart compression sock designed to address this issue by integrating temperature, plantar pressure, and blood oxygen sensors and monitoring data recorded by these sensors. The smart sock, developed with input from a certified Pedorthist, was tested on 20 healthy adult participants aged 16 to 53. It includes four temperature sensors and pressure sensors at common ulcer sites (first and fifth metatarsal heads, calcaneus, and hallux), and a blood oxygen sensor on the hallux. The sensors are monitored, and their transduced data are collected and stored through an app installed on a personal cell phone. The mobile app interface is user-friendly, providing intuitive navigation and easy access to the sensors’ data. Using repeated measures ANOVA and post hoc tests, we analyzed the impact of various physical activities on physiological changes in the foot. The device effectively detected significant variations in blood oxygen, temperature, and pressure across six activities. Statistical analyses revealed significant differences based on activity type and sensor location. These results highlight the smart sock’s sensitivity and accuracy, suggesting its potential to prevent diabetic foot ulcers. Further clinical trials are needed to evaluate its efficacy in a larger, more diverse population.
... Examples of self-powered WSNs that use a piezoelectric transducer as an energy source are presented in [10][11][12][13], and include gas pipeline monitoring, wind speed sensing, wildfire detection, and traffic management applications. Foot temperature monitoring is one of the most effective methods to detect inflammation that leads to ulceration (in diabetic patients experiencing foot complications) [14]. Elevated foot temperature can alert the patient to seek treatment or about reduced activity until the temperature is normalized, which can effectively prevent foot ulcerations. ...
... Foot temperature monitoring is one of the most effective methods to detect inflammation that leads to ulceration (in diabetic patients experiencing foot complications) [14]. Elevated foot temperature can alert the patient to seek treatment or about reduced activity until the temperature is normalized, which can effectively prevent foot ulcerations. ...
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This work describes a self-powered wireless temperature sensor platform that can be used for foot ulceration monitoring for diabetic patients. The proposed self-powered sensor platform consists of a piezoelectric bimorph, a power conditioning circuit, a temperature sensor readout circuit, and a wireless module. The piezoelectric bimorph mounted inside the shoe effectively converts the foot movement into electric energy that can power the entire sensor platform. Furthermore, a sensor platform was designed, considering the energy requirement of 4.826 mJ for transmitting one data packet of 18 bytes. The self-powered sensor platform prototype was evaluated with five test subjects with different weights and foot shapes; the test results show the subjects had to walk an average of 119.6 s to transmit the first data packet and an additional average of 71.2 s to transmit the subsequent data packet. The temperature sensor showed a resolution of 0.1 °C and a sensitivity of 56.7 mV/°C with a power conditioning circuit efficiency of 74.5%.
... By measuring the temperature difference between the same parts of the feet, we can find the potential risk of DFUs and the common alert threshold is 2.2°C (Lavery et al., 2004). Patients doing self-care at home are often unable to accurately self-assess their condition, and are often treated too late when their feet become necrotic. ...
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Background and Aims Diabetic foot ulcers (DFUs) are a serious complication of diabetes mellitus (DM), affecting around 25% of individuals with DM. Primary treatment of a DFU involves wound off-loading, surgical debridement, dressings to provide a moist wound environment, vascular assessment, and appropriate antibiotics through a multidisciplinary approach. Three-dimensional (3D) printing technology is considered an innovative tool for the management of DFUs. The utilization of 3D printing technology in the treatment of DFU involves the modernization of traditional methods and the exploration of new techniques. This review discusses recent advancements in 3D printing technology for the application of DFU care, and the development of personalized interventions for the treatment of DFUs. Methods We searched the electronic database for the years 2019–2024. Studies related to the use of 3D printing technology in Diabetic foot were included. Results A total of 25 identified articles based on database search and citation network analysis. After removing duplicates, 18 articles remained, and three articles that did not meet the inclusion criteria were removed after reading the title/abstract. A total of 97 relevant articles were included during the reading of references. In total, 112 articles were included. Conclusion 3D printing technology offers unparalleled advantages, particularly in the realm of personalized treatment. The amalgamation of traditional treatment methods with 3D printing has yielded favorable outcomes in decelerating the progression of DFUs and facilitating wound healing. However, there is a limited body of research regarding the utilization of 3D printing technology in the domain of DFUs.
Article
This commentary considers the similarities which exist between pressure ulcers (PUs) and diabetic foot ulcers (DFUs). It aims to describe what is known to be shared—both in theory and practice—by these wound types. It goes on to detail the literature surrounding the role of inflammation in both wound types. PUs occur following prolonged exposure to pressure or pressure in conjunction with shear, either due to impaired mobility or medical devices. As a result, inflammation occurs, causing cell damage. While DFUs are not associated with immobility, they are associated with altered mobility occurring as a result of complications of diabetes. The incidence and prevalence of both types of lesions are increased in the presence of multimorbidity. The prediction of either type of ulceration is challenging. Current risk assessment practices are reported to be ineffective at predicting when ulceration will occur. While systemic inflammation is easily measured, the presence of local or subclinical inflammation is harder to discern. In patients at risk of either DFUs or PUs, clinical signs and symptoms of inflammation may be masked, and systemic biomarkers of inflammation may not be elevated sufficiently to predict imminent damage until ulceration appears. The current literature suggests that the use of local biomarkers of inflammation at the skin's surface, namely oedema and temperature, may identify early tissue damage.
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The prevalence of diabetic foot ulcers (DFUs) is 4 to 10% among people with diabetes mellitus. DFUs are associated with increased morbidity and mortality as well as reduced quality of life and have a significant impact on overall healthcare expenditure. The main predisposing factors for DFU are diabetic neuropathy, peripheral arterial disease, and trauma. The fact that a range of tests can be used to identify patients at risk for DFU often causes confusion among practitioners regarding which screening tests should be implemented in clinical practice. Herein we sought to determine whether tests of somatic nerve function, such as pinprick sensation, thermal (cold/hot) test, ankle reflexes, vibration perception, 10-g monofilament, Ipswich touch test, neuropathy disability score, and nerve conduction studies, predict the development of DFUs. In addition, we examined whether sudomotor function screening tests, such as Neuropad, sympathetic skin response, and other tests, such as elevated plantar pressure or temperature measurements, can be used for DFU screening. If not treated properly, DFUs can have serious consequences, including amputation, early detection and treatment are vital for patient outcomes.
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Charcot's joint (neuropathic osteoarthropathy) is a progressive condition affecting the musculoskeletal system and is characterized by joint dislocation, pathologic fractures, and often debilitating deformities (Figs. 1 and 2).¹ The condition most commonly occurs in patients with diabetes mellitus who have severe peripheral neuropathies. The prevalence of Charcot's joint is variable, ranging from 0.16% of all patients with diabetes² to as high as 13% of patients receiving care at a high-risk diabetic foot clinic.¹ The frequency of diagnosis of this condition appears to be increasing as a result of increased awareness of its signs and symptoms. The Etiology of Neuropathic Osteoarthropathy (Charcot's Joint) Neuropathic osteoarthropathy was first reported by Musgrave in 1703.³ He described it as an arthralgia secondary to venereal disease. In 1868, the noted French neurologist Jean-Martin Charcot became the first investigator to concisely describe the neuropathic component of the disease.⁴…
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Background A comprehensive understanding of clinical risk factors for developing foot ulcerations would help clinicians to categorize patients by their risk status and schedule intervention resources accordingly to prevent amputation. Objective To evaluate risk factors for foot ulcerations among persons with diabetes mellitus. Method We enrolled 225 age-matched patients, 46.7% male, with a ratio of approximately 1:2 cases:controls (76 case-patients and 149 control subjects). Case-patients were defined as subjects who met the enrollment criteria and who had an existing foot ulceration or a recent history of a foot ulceration. Control subjects were defined as subjects with no history of foot ulceration. A stepwise logistic regression model was used for analysis. Results An elevated plantar pressure (>65 N/cm2), history of amputation, lengthy duration of diabetes (>10 years), foot deformities (hallux rigidus or hammer toes), male sex, poor diabetes control (glycosylated hemoglobin >9%), 1 or more subjective symptoms of neuropathy, and an elevated vibration perception threshold (>25 V) were significantly associated with foot ulceration. In addition, 59 patients (78%) with ulceration had a rigid deformity directly associated with the site of ulceration. No significant associations were noted between vascular disease, level of formal education, nephropathy, retinopathy, impaired vision, or obesity and foot ulceration on multivariate analysis. Conclusions Neuropathy, foot deformity, high plantar pressures, and a history of amputation are significantly associated with the presence of foot ulceration. Although vascular and renal disease may result in delayed wound healing and subsequent amputation, they are not significant risk factors for the development of diabetic foot ulceration.
Article
The natural history of tissue repair and the critical determinants of faulty healing of diabetic ulcers remain obscure despite recent advances in our knowledge of the cellular physiology of normal cutaneous healing. To characterize the chronology and identify important factors affecting healing, we applied an objective method to quantify the rate of wound healing of full-thickness lower-extremity ulcers in 46 diabetic outpatients who received local wound care under a standardized clinical protocol. The initial ulcer healing rate, eventual status of tissue repair, and definitive clinical outcome were not significantly associated with age; diabetes type, duration, or treatment; level or change in glycosylated hemoglobin; current smoking; presence of sensory neuropathy; ulcer location or class; initial infection; or frequency of recurrent infections. However, direct measures of local cutaneous perfusion, estimated by periwound measurements of transcutaneous O2 tension (TcPo2) and transcutaneous CO2 tension (TcPco2), were significantly associated with the initial rate of tissue repair (P = 0.003 and 0.005, respectively). The strong prediction of early healing by these parameters of local skin perfusion was independent from the effects of segmental Doppler arterial blood pressure at the dorsalis pedis, although eventual ulcer reepithelialization was significantly related to foot blood pressure and periwound TcPo2 and TcPco2. We conclude that periwound cutaneous perfusion is the critical physiological determinant of diabetic ulcer healing, indicating a 39-fold increased risk of early healing failure when the average periwound TcPo2 is less than 20 mmHg.
Article
The response of skin blood cell flux (SBF) to locally applied pressure was evaluated with the laser-Doppler technique in the areas of the sacrum and the gluteus maximus muscle of geriatric patients and healthy young and elderly subjects. The SBF over the sacrum stopped at a lower external skin pressure than over the gluteus muscle in all groups studied (P<0·05·0·001). The SBF at rest was lower among geriatric patients and over the sacrum, with men showing the lowest value (P<0·001). The initial slope of the SBF curve and the peak SBF during the post-occlusive reactive hyperaemia (PRH) were lower among geriatric patients compared to younger healthy subjects (P<0·05·0·01) over both areas studied. During the last part of the PRH response rhythmic oscillations started, known as vasomotion. The mean skin temperature at rest was higher over the sacrum (P<0·001) than over the gluteus area, but no difference was found between the groups. The temperature increase during the PRH was larger over the gluteus muscle (P<0·01) than over the sacrum area in the healthy subjects. Among the patients the temperature increase was larger over the gluteus only during the first half of the PRH, after which the temperature increased most over the sacrum. It is concluded that SBF and skin temperature show different responses in microvascular reactivity to external pressure in elderly vs. younger subjects and also between sexes. The described technique may be useful in clinical practice for predicting the risk of pressure sores in different areas and subjects.
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We defined the causal pathways responsible for 80 consecutive initial lower-extremity amputations to an extremity in diabetic patients at the Seattle Veterans Affairs Medical Center over a 30-mo interval from 1984 to 1987. Causal pathways, either unitary or composed of various combinations of seven potential causes (i.e., ischemia, infection, neuropathy, faulty wound healing, minor trauma, cutaneous ulceration, gangrene), were determined empirically after a synthesis by the investigators of various objective and subjective data. Estimates of the proportion of amputations that could be ascribed to each component cause were calculated. Twenty-three unique causal pathways to diabetic limb amputation were identified. Eight frequent constellations of component causes resulted in 73% of the amputations. Most pathways were composed of multiple causes, with only critical ischemia from acute arterial occlusions responsible for amputations as a singular cause. The causal sequence of minor trauma, cutaneous ulceration, and wound-healing failure applied to 72% of the amputations, often with the additional association of infection and gangrene. We specified precise criteria in the definition of causal pathway to permit estimation of the cumulative proportion of amputations due to various causes. Forty-six percent of the amputations were attributed to ischemia, 59% to infection, 61% to neuropathy, 81% to faulty wound healing, 84% to ulceration, 55% to gangrene, and 81% to initial minor trauma. An identifiable and potentially preventable pivotal event, in most cases an episode involving minor trauma that caused cutaneous injury, preceded 69 to 80 amputations. Defining causal pathways that predispose to diabetic limb amputation suggests practical interventions that may be effective in preventing diabetic limb loss.
Article
The effect of prolonged local pressure on the skin microcirculation was investigated in the regions of the sacrum and gluteus maximus muscle to determine the aetiology of pressure sores. Thirty normal subjects (15 female, 15 male) were investigated. The subjects were divided into three age groups: group 1, ≤ 35 years; group 2, 36–64 years; and group 3, ≥ 65 years. Local pressure was applied with a specially designed instrument according to the sequence 0→ 110→ 0→ 110→ 0→ mmHg. Skin blood cell flux (SBF) was measured with a laser–Doppler technique and the local skin temperature measured with a thermistor. No significant differences were seen in SBF due to sex or age. However, differences between the two areas studied were observed. SBF was maximal over the sacrum at 12–50 mmHg (1.6–6.7 kPa) applied pressure. With further pressure increases, the SBF signal decreased successively, reaching minimum level at 110 mmHg (14.6 kPa), where it was approximately 43% below the initial value. The SBF in the gluteus region showed a more stable pattern, with a maximum SBF at 13–60 mmHg (1.7–8.0 kPa). At both locations, an increased SBF at zero pressure was seen when the pressure was decreased from 110 to 0 mmHg. The skin temperature (n = 7) increased by 2.7°C (range 1.9–3.5°C) over the gluteus and by 1.3°C (range 0.8–2.5°C) over the sacrum. This increase was more rapid over the gluteus region. Concomitantly a temperature-dependent increase of SBF could be seen. It is concluded that a cause for the greater frequency of pressure sores over the sacrum than over the gluteus region is the comparatively poorer regulation of microvascular flow in this area.