Epidemiology of Non-Traumatic Lower Extremities Amputations in West Africa: Nationwide Data from Togo.

OBJECTIVE: Non-traumatic lower limb amputation (NT-LLA) has consequences at individual and public health levels. Population based studies in sub-Saharan Africa are scarce and often related to single centre series. This study aimed to estimate the incidence of NT-LLA (minor and major) and to describe epidemiological, clinical, and prognostic aspects in Togo. METHODS: This was a population based observational study conducted among all patients who underwent NT-LLA. Traumatic amputations were excluded. Sociodemographic, clinical, and work up data were collected from clinical files in any Togolese health centre from 1 January 2016 to 31 December 2021. Incidence rates were adjusted for age. RESULTS: Over the six year period, 352 patients (59% males) underwent NT-LLA (mean ± standard deviation age 60 ± 15.7 years). The average age adjusted incidence rate of NT-LLA was 8.5 per million/year (95% confidence interval [CI] 7.6 - 9.4). Men were 1.7 times more likely to undergo a NT-LLA than women. The relative risk of NT-LLA was 48 times higher in patients with diabetes than in patients without diabetes. Around 61.0% of the NT-LLAs occurred within the 50 - 74 age group and 54.3% had diabetes mellitus. Among amputees, 54.5% had a diagnosis of peripheral artery disease (PAD) and 52.8% had diabetic ulcers, with co-existence of several factors. Less than 5% of participants had a history of smoking tobacco. Average length of hospital stay was 12 days. The in hospital mortality rate was 8.8% (9.0% for major, 6.7% for minor amputations). Only 18.2% had duplex ultrasound performed and 1.7% angiography prior to amputation. No patient underwent vascular intervention prior to amputation. CONCLUSION: This is the first study to report nationwide and contemporary epidemiological data on NT-LLAs in West Africa, highlighting several specificities. Large scale interventions are needed to ameliorate the care of diabetes and PAD and improve facilities for optimal management of patients at risk of amputation in Africa.

Neuropsychiatric drugs and a neurophysiological marker as predictors of health-related quality of life in patients with phantom limb pain.

OBJECTIVE: To explore the relationship between sociodemographic, clinical, and neurophysiological variables and health-related quality of life (HR-QOL) of patients with phantom limb pain. METHODS: This is a cross-sectional analysis of a previous clinical trial. Univariate and multivariate linear and logistic regression analyses were used to model the predictors of HR-QOL. We utilized a sequential modeling approach with increasing adjustment levels, controlling for age and sex, and other relevant clinical variables (time since amputation, level of amputation, and pain). HR-QOL was assessed by the SF-36 Health Survey and its eight subdomains. RESULTS: We analyzed baseline data from 92 patients with lower-limb amputations. They were mostly male (63%), 45.2 ± 15.6 years, with a mean time since amputation of 82.7 ± 122.4 months, and an overall SF-36 score of 55.9 ± 21.5. We found an association between intracortical facilitation in the affected hemisphere (ICF), gabapentin usage, and HR-QOL. ICF is a predictor of better HRQOL, whereas gabapentin usage was associated with a poorer HR-QOL, with the main model explaining 13.4% of the variance in the outcome. For the SF-36 subdomains, ICF was also a positive predictor for social functioning, bodily pain, and vitality, while medication usage was associated with lower scores in mental health, general health perception, bodily pain, and vitality. CONCLUSION: We found firsthand two new independent predictors of HR-QOL in individuals with PLP, namely, the neurophysiological metric ICF and gabapentin usage. These results highlight the role of the motor cortex excitability in the HR-QOL and stress the need for treatments that favor the neuroplastic adaptation after amputation, for which ICF may be used as a possible marker.

Epidemiology of Limb Amputations and Prosthetic Use During COVID-19 Pandemic in the Netherlands.

OBJECTIVE: To evaluate the trends in the incidence of major limb amputations and the prevalence of Dutch prosthetic users at the national level in The Netherlands between 2012 and 2021 (during the COVID-19 pandemic). Local hospitals in The Netherlands reported a doubling of major lower limb amputations during COVID-19, information about a change in the incidence of major upper limb amputations was not reported. We could not confirm this remarkable increase in major lower limb amputations in our institution, nor did we observe a change in the incidence of major upper limb amputations. We hypothesize that the COVID-19 pandemic had no effect on the number of major limb amputations. DESIGN: Observational retrospective study analyzing national open-access databases of health insurance claims. SETTING: The Dutch national opensource database www.opendisdata.nl was used to retrieve the incidence of limb amputations in the period 2012-2021, stratified by the level of amputation and the cause of amputation. The results were verified using the www.gipdatabank.nl databank. This period included 4 intervals of nationwide COVID-19 lockdowns. PARTICIPANTS: 60,848 patients who underwent limb amputations at the upper or lower extremity in the Netherlands from 2012 to 2021 (N=60,848) were included in this study. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Upper- and lower-limb amputation and prosthetic use. RESULTS: Data were retrieved for a total of 60,848 patients in the Netherlands, who underwent 68,180 amputations of the upper and lower extremities at any level from 2012 to 2021, including 22,095 major amputations of the lower extremities. The ongoing trend of stable numbers of major lower-limb amputations from 2012 to 2019 continued in 2020 and 2021. The verification of these data at the level of prosthetic users confirmed that the annual trends were unchanged. CONCLUSION: The reported increased numbers of major lower-limb amputations during the COVID-19 pandemic in the Netherlands could not be confirmed using nationwide epidemiologic data.

Validation of Proprietary and Novel Step-counting Algorithms for Individuals Ambulating With a Lower Limb Prosthesis.

OBJECTIVE: To compare the accuracy and reliability of 10 different accelerometer-based step-counting algorithms for individuals with lower limb loss, accounting for different clinical characteristics and real-world activities. DESIGN: Cross-sectional study. SETTING: General community setting (ie, institutional research laboratory and community free-living). PARTICIPANTS: Forty-eight individuals with a lower limb amputation (N=48) wore an ActiGraph (AG) wGT3x-BT accelerometer proximal to the foot of their prosthetic limb during labeled indoor/outdoor activities and community free-living. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Intraclass correlation coefficient (ICC), absolute and root mean square error (RMSE), and Bland Altman plots were used to compare true (manual) step counts to estimated step counts from the proprietary AG Default algorithm and low frequency extension filter, as well as from 8 novel algorithms based on continuous wavelet transforms, fast Fourier transforms (FFTs), and peak detection. RESULTS: All algorithms had excellent agreement with manual step counts (ICC>0.9). The AG Default and FFT algorithms had the highest overall error (RMSE=17.81 and 19.91 steps, respectively), widest limits of agreement, and highest error during outdoor and ramp ambulation. The AG Default algorithm also had among the highest error during indoor ambulation and stairs, while a FFT algorithm had the highest error during stationary tasks. Peak detection algorithms, especially those using pre-set parameters with a trial-specific component, had among the lowest error across all activities (RMSE=4.07-8.99 steps). CONCLUSIONS: Because of its simplicity and accuracy across activities and clinical characteristics, we recommend the peak detection algorithm with set parameters to count steps using a prosthetic-worn AG among individuals with lower limb loss for clinical and research applications.

The Effect of Prosthetic Limb Sophistication and Amputation Level on Self-reported Mobility and Satisfaction With Mobility.

OBJECTIVE: To determine if lower limb prosthesis (LLP) sophistication is associated with patient-reported mobility and/or mobility satisfaction, and if these associations differ by amputation level. DESIGN: Cohort study that identified participants through a large national database and prospectively collected self-reported patient outcomes. SETTING: The Veterans Administration (VA) Corporate Data Warehouse, the National Prosthetics Patient Database, participant mailings, and phone calls. PARTICIPANTS: 347 Veterans who underwent an incident transtibial (TT) or transfemoral (TF) amputation due to diabetes and/or peripheral artery disease and received a qualifying LLP between March 1, 2018, and November 30, 2020. INTERVENTIONS: Basic, intermediate, and advanced prosthesis sophistication was measured by the accurate and reliable PROClass system. MAIN OUTCOME MEASURE: Patient-reported mobility using the advanced mobility subscale of the Locomotor Capabilities Index-5; mobility satisfaction using a 0-10-point Likert scale. RESULTS: Lower limb amputees who received intermediate or advanced prostheses were more likely to achieve advanced mobility than those who received basic prostheses, with intermediate nearing statistical significance at nearly twice the odds (adjusted odds ratio (aOR)=1.8, 95% confidence interval (CI), .98-3.3; P=.06). The association was strongest in TF amputees with over 10 times the odds (aOR=10.2, 95% CI, 1.1-96.8; P=.04). The use of an intermediate sophistication prosthesis relative to a basic prosthesis was significantly associated with mobility satisfaction (adjusted ß coefficient (aß)=.77, 95% CI, .11-1.4; P=.02). A statistically significant association was only observed in those who underwent a TT amputation (aß=.79, 95% CI, .09-1.5; P=.03). CONCLUSIONS: Prosthesis sophistication was not associated with achieving advanced mobility in TT amputees but was associated with greater mobility satisfaction. In contrast, prosthesis sophistication was associated with achieving advanced mobility in TF amputees but was not associated with an increase in mobility satisfaction.

Patient satisfaction after lower limb replantation surgery for traumatic amputation - a qualitative study.

BACKGROUND: The majority of published literature clinically assesses surgical outcomes after lower limb replantation for traumatic amputations. However, patients' satisfaction and quality of life may not be accurately measured through rigid scoring using standardized patient reported outcome measures. PURPOSE: The aim of this study was to qualitatively assess patient satisfaction and factors associated with achieving good outcomes after successful lower limb replantation surgery. METHODS: A semi-structured interview was conducted with 12 patients who underwent lower limb replantation surgery following traumatic amputation injuries. The interview focused on the patients' experience and satisfaction throughout their injury, surgical journey, rehabilitation and reintegration into their communities. An inductive and deductive thematic analysis was applied using the recorded transcripts to evaluate the overall satisfaction of the patients after lower limb replantation surgery. RESULTS: The following observations emerged from the structured themes among all the patients interviewed: (1) Family and social support was significantly associated with improved qualities of life and satisfaction after lower limb replantation; (2) Patients were generally satisfied with their outcomes despite limitations in physical capabilities; (3) Satisfaction was associated with acceptance of their cosmetic deformity; (4) Social integration and being able to participate in a meaningful manner was associated with greater satisfaction after recovery. CONCLUSIONS: Patients who undergo lower limb replantation can have a significantly improved quality of life if they have strong social support, are able to contribute in a meaningful manner to their communities after surgery, and are accepting of their cosmetic deficiencies.

Can Early Post-Operative Scoring of Non-Traumatic Amputees Decrease Rates of Revision Surgery?

Background and Objectives: Medical registries evolved from a basic epidemiological data set to further applications allowing deriving decision making. Revision rates after non-traumatic amputation are high and dramatically impact the following rehabilitation of the amputee. Risk scores for revision surgery after non-traumatic lower limb amputation are still missing. The main objective was to create an amputation registry allowing us to determine risk factors for revision surgery after non-traumatic lower-limb amputation and to develop a score for an early detection and decision-making tool for the therapeutic course of patients at risk for non-traumatic lower limb amputation and/or revision surgery. Materials and Methods: Retrospective data analysis was of patients with major amputations lower limbs in a four-year interval at a University Hospital of maximum care. Medical records of 164 patients analysed demographics, comorbidities, and amputation-related factors. Descriptive statistics analysed demographics, prevalence of amputation level and comorbidities of non-traumatic lower limb amputees with and without revision surgery. Correlation analysis identified parameters determining revision surgery. Results: In 4 years, 199 major amputations were performed; 88% were amputated for non-traumatic reasons. A total of 27% of the non-traumatic cohort needed revision surgery. Peripheral vascular disease (PVD) (72%), atherosclerosis (69%), diabetes (42%), arterial hypertension (38%), overweight (BMI > 25), initial gangrene (47%), sepsis (19%), age > 68.2 years and nicotine abuse (17%) were set as relevant within this study and given a non-traumatic amputation score. Correlation analysis revealed delayed wound healing (confidence interval: 64.1% (47.18%; 78.8%)), a hospital length of stay before amputation of longer than 32 days (confidence interval: 32.3 (23.2; 41.3)), and a BKA amputation level (confidence interval: 74.4% (58%; 87%)) as risk factors for revision surgery after non-traumatic amputation. A combined score including all parameters was drafted to identify non-traumatic amputees at risk for revision surgery. Conclusions: Our results describe novel scoring systems for risk assessment for non-traumatic amputations and for revision surgery at non-traumatic amputations. It may be used after further prospective evaluation as an early-warning system for amputated limbs at risk of revision.

[Lower Limb Amputations in Patients with Peripheral Arterial Disease and/or Diabetes in Iceland 2010-2019; revascularisation, comorbidities and risk factors].

INTRODUCTION: No recent studies exist on lower extremity amputations (LLAs) in Iceland. The aim of this study was to investigate LLA incidence in Iceland 2010-2019 and preceding procedures in amputations induced by peripheral arterial disease (PAD) and diabetes mellitus (DM). MATERIAL AND METHODS: Retrospective study on clinical records of all patients (>18 years) who underwent LLA in Iceland's two main hospitals during 2010-2019. Patients were excluded if LLA was performed for reasons other than DM and/or PAD. Symptoms, medication and circulation assessment were recorded from first hospital visit due to symptoms, and prior to the last LLA, respectively. Previous arterial surgeries and amputations were also recorded. RESULTS: A total of 167 patients underwent LLA. Thereof, 134 (77 ± 11 years, 93 men and 41 woman) due to DM and/or PAD. The LLA-rate due to those diseases increased from 4.1/100,000 inhabitants in 2010-2013 to 6.7/100,000 in 2016-2019 (p=0,04). Risk factors were mainly hypertension, 84%, and smoking, 69%. Chronic limb-threatening ischemia induced 71% of first hospital visits. Revascularisations were performed (66% endovascular) in 101 patients. Non-diabetic patients were 52% and had statins less frequently prescribed than DM patients (26:45, p<0.001). CONCLUSION: DM and/or PAD are the leading causes of LLA in Iceland. Amputation rate increased during the period but is low in an international context. Amputation is most often preceded by arterial surgery. DM is present in almost half of cases, similar or less than in most other countries. Opportunities for improved prevention should aim on earlier diagnosis and preventive treatment of non-diabetic individuals with PAD.

Clinical utility of 67 Gallium-SPECT/CT for determining osteotomy indication in patients with lower-limb osteomyelitis.

Standard non-invasive methods for diagnosing and selecting the best treatment for osteomyelitis in patients with multiple chronic conditions remain to be established. We aimed to evaluate the ability of quantitative 67 Ga-citrate single-photon emission computed tomography (67 Ga-SPECT/CT) to determine the indication for either non-surgical treatment or osteotomy in patients with lower-limb osteomyelitis (LLOM) associated with diabetes mellitus and lower-extremity ischemia, based on monitoring of inflammatory activity in bone tissue. This single-centre prospective study conducted from January 2012 to July 2017 included 90 consecutive patients with suspected LLOM. Regions of interest were drawn on SPECT images during quantification of Ga accumulation. Subsequently, the inflammation-to-background ratio (IBR) was calculated by dividing the maximal accumulated lesion number by the mean number for the distal femur bone marrow of the unaffected side. Osteotomy was performed in 28 of 90 patients (31%). The osteotomy rate was higher for patients with IBR >8.4 (71.4%) than for those with IBR ≤8.4 (5.5%) (p < 0.001, sensitivity: 0.89, specificity: 0.84). In the multivariate Cox regression analysis, IBR >8.4 was an independent risk factor for osteotomy (hazard ratio [HR]: 19.0, 95% confident interval [CI]: 5.6-63.9, p < 0.001). Transcutaneous oxygen tension (TcPO2 ) was identified as an independent risk factor for lower-limb amputation (HR: 0.96, 95% CI: 0.92-0.99, p = 0.01). The current results indicate that quantitative 67 Ga-SPECT/CT is useful for distinguishing patients with LLOM likely to require osteotomy.

Continuous relative phases of walking with an articulated passive ankle-foot prosthesis in individuals with a unilateral transfemoral and transtibial amputation: an explorative case-control study.

BACKGROUND: A mechanical ankle-foot prosthesis (Talaris Demonstrator) was developed to improve prosthetic gait in people with a lower-limb amputation. This study aims to evaluate the Talaris Demonstrator (TD) during level walking by mapping coordination patterns based on the sagittal continuous relative phase (CRP). METHODS: Individuals with a unilateral transtibial amputation, transfemoral amputation and able-bodied individuals completed 6 minutes of treadmill walking in consecutive blocks of 2 minutes at self-selected (SS) speed, 75% SS speed and 125% SS speed. Lower extremity kinematics were captured and hip-knee and knee-ankle CRPs were calculated. Statistical non-parametric mapping was applied and statistical significance was set at 0.05. RESULTS: The hip-knee CRP at 75% SS walking speed with the TD was larger in the amputated limb of participants with a transfemoral amputation compared to able-bodied individuals at the beginning and end of the gait cycle (p = 0.009). In people with a transtibial amputation, the knee-ankle CRP at SS and 125% SS walking speeds with the TD were smaller in the amputated limb at the beginning of the gait cycle compared to able-bodied individuals (p = 0.014 and p = 0.014, respectively). Additionally, no significant differences were found between both prostheses. However, visual interpretation indicates a potential advantage of the TD over the individual's current prosthesis. CONCLUSION: This study provides lower-limb coordination patterns in people with a lower-limb amputation and reveals a possible beneficial effect of the TD over the individuals' current prosthesis. Future research should include a well-sampled investigation of the adaptation process combined with the prolonged effects of the TD.

Decreasing national trends in diabetic complications hide regional differences: a prospective population-based study using health care registers in Finland.

Objectives. To examine whether possibilities to improve care among patients with diabetes are reflected in the numbers of cardiovascular complications at national and regional level in Finland. Methods. The study population included all patients with diabetes in Finland since 1964. The incidences of first acute coronary syndrome, ischemic stroke and lower limb amputation were examined for the period from 2010 to 2017. The age- and sex-standardised incidence rates were calculated for the first events. Adjusted Poisson regression mixed models were used to calculate average annual trends and assess regional variation of incidences during the periods 2010 to 2013 and 2014 to 2017 in the university hospital districts (UHDs) and hospital districts (HDs). Results. The nationwide incidence of first acute coronary syndrome decreased among patients with diabetes by 2.7% (95% confidence interval 2.3%; 3.0%), ischemic stroke by 2.0% (1.5%; 2.4%) and major lower limb amputation by 4.6% (3.1%; 5.9%) annually. The sexes differed only in the decrease in acute coronary events. The annual decrease among males was 2.1% (1.6%; 2.6%) and among females was 3.4% (2.8%; 4.0%) (p = .001). Marked variation was observed among UHDs and HDs in the incidences of cardiovascular events and lower limb amputations in patients with diabetes. The variation in annual trends of diabetic complications was most pronounced in acute coronary syndrome among UHDs with an estimated variance of 0.0006 (p = .034). Conclusions. The decrease in the incidence of first cardiovascular events among patients with diabetes continued from 2010 to 2017 in Finland. However, the declining national incidence rates hide regional differences which should be a target for improvement.

The influence of simultaneous pancreas-kidney transplantation on the evolution of diabetic foot lesions and peripheral arterial disease.

PURPOSE: Simultaneous pancreas-kidney transplantation (SPKT) remains the best treatment option in patients with type 1 diabetes and chronic kidney failure. There are only a few studies addressing the potential ischemic deterioration of peripheral arterial disease (PAD) due to blood diverting from the iliac artery to the kidney graft. We aimed to evaluate diabetic foot lesions and PAD evolution in SPKT recipients and investigate if they are more frequent in ipsilateral lower limb of kidney graft. METHODS: We developed a retrospective cohort, including patients submitted to SPKT in our tertiary center, between 2000 and 2017. Diabetic foot lesions and PAD frequencies were compared in the period before and after transplantation. RESULTS: Two hundred and eleven patients were included, 50.2% (n = 106) female, with a median age at transplantation of 35 years (IQR 9). After a median follow-up period of 10 years (IQR 7), patient, kidney, and pancreatic graft survival were 90.5% (n = 191), 83.4% (n = 176), and 74.9% (n = 158), respectively. Before transplant, 2.8% (n = 6) had PAD and 5.3% (n = 11) had history of foot lesions. In post-transplant period, 17.1% (n = 36) patients presented PAD and 25.6% (n = 54) developed diabetic foot ulcers, 47.6% (n = 35) of which in the ipsilateral and 53.3% (n = 40) in the contralateral lower limb of the kidney graft (p = 0.48). Nine patients (4.3%) underwent major lower limb amputation, 3 (30%) ipsilateral and 7 (70%) contralateral to the kidney graft (p = 0.29). CONCLUSIONS: Diabetic foot lesions were not more frequent in the ipsilateral lower limb of the kidney graft, therefore downgrading the 'steal syndrome' role in these patients.

The Effect of Advanced Age on Prosthetic Rehabilitation Functional Outcomes in People With Lower Limb Amputations: A Retrospective Chart Audit of Inpatient Admissions.

OBJECTIVE: To evaluate the effect of age on functional outcomes at discharge from prosthetic rehabilitation. DESIGN: Retrospective chart audit. SETTING: Rehabilitation hospital. PARTICIPANTS: Individuals ≥50 years with a transtibial level lower limb amputation (LLA) and above admitted to the inpatient prosthetic rehabilitation program from 2012 to 2019 (n=504). A secondary analysis included a subset of matched participants (n=156). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The L-Test of Functional Mobility (L-Test), 2-Minute Walk Test (2MWT), 6-Minute Walk Test (6MWT), and Activities-specific Balance Confidence scale. RESULTS: A total of 504 participants (66.7±10.1 years) met the inclusion criteria, 63 participants (84.9±3.7 years) were part of the oldest old group. The sample was stratified into 4 age groups (50-59, 60-69, 70-79, and 80+) for data analysis. The analysis of variances were statistically significant for all outcome measures (P<.001). Post-hoc testing for the L-Test, 2MWT, and 6MWT demonstrated that the oldest old had significantly reduced performance compared with people 50-59 years old (P<.05), but there were no significant differences between the oldest old and the 60-69 [(L-Test, P=.802), (2MWT, P=.570), (6MWT, P=.772)] and 70-79 [(L-Test, P=.148), (2MWT, P=.338), (6MWT, P=.300)] age groups. The oldest old reported significantly lower balance confidence compared with all 3 age groups (P<.05). CONCLUSION: The oldest old achieved similar functional mobility outcomes as people 60-79 years, the most common age group of people with an LLA. Advanced age alone should not disqualify individuals from prosthetic rehabilitation.

Identifying Health-Related Quality of Life Domains After Upper Extremity Transplantation.

OBJECTIVE: To identify the most important health-related quality of life (HRQOL) domains and patient-reported outcomes after upper extremity transplantation (UET) in individuals with upper extremity amputation. DESIGN: Verbatim audio-recordings of individual interviews and focus groups were analyzed using qualitative, grounded theory-based methods to identify important domains of HRQOL and provide guidance for outcomes measurement after UET. SETTING: Individual interviews were conducted by phone. Focus groups were conducted at 5 upper extremity vascularized composite allotransplantation (VCA) centers in the US and at an international conference of VCA experts. PARTICIPANTS: Individual phone interviews were conducted with 5 individuals with lived experience of UET. Thirteen focus groups were conducted with a total of 59 clinical professionals involved in UET. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Not applicable. RESULTS: Twenty-eight key HRQOL domains were identified, including physical functioning and medical complications, positive and negative emotional functioning, and social participation, relations, and independence. We identified key constructs for use in evaluation of the potentially substantial physical, medical, social, and emotional effects of UET. CONCLUSIONS: This study provides an overview of the most important issues affecting HRQOL after UET, including several topics that are unique to individuals with UET. This information will be used to establish systematic, comprehensive, and longitudinal measurement of post-UET HRQOL outcomes.

Integration of proprioception in upper limb prostheses through non-invasive strategies: a review.

Proprioception plays a key role in moving our body dexterously and effortlessly. Nevertheless, the majority of investigations evaluating the benefits of providing supplemental feedback to prosthetics users focus on delivering touch restitution. These studies evaluate the influence of touch sensation in an attempt to improve the controllability of current robotic devices. Contrarily, investigations evaluating the capabilities of proprioceptive supplemental feedback have yet to be comprehensively analyzed to the same extent, marking a major gap in knowledge within the current research climate. The non-invasive strategies employed so far to restitute proprioception are reviewed in this work. In the absence of a clearly superior strategy, approaches employing vibrotactile, electrotactile and skin-stretch stimulation achieved better and more consistent results, considering both kinesthetic and grip force information, compared with other strategies or any incidental feedback. Although emulating the richness of the physiological sensory return through artificial feedback is the primary hurdle, measuring its effects to eventually support the integration of cumbersome and energy intensive hardware into commercial prosthetic devices could represent an even greater challenge. Thus, we analyze the strengths and limitations of previous studies and discuss the possible benefits of coupling objective measures, like neurophysiological parameters, as well as measures of prosthesis embodiment and cognitive load with behavioral measures of performance. Such insights aim to provide additional and collateral outcomes to be considered in the experimental design of future investigations of proprioception restitution that could, in the end, allow researchers to gain a more detailed understanding of possibly similar behavioral results and, thus, support one strategy over another.

The impact of walking on the perception of multichannel electrotactile stimulation in individuals with lower-limb amputation and able-bodied participants.

BACKGROUND: One of the drawbacks of lower-limb prostheses is that they do not provide explicit somatosensory feedback to their users. Electrotactile stimulation is an attractive technology to restore such feedback because it enables compact solutions with multiple stimulation points. This allows stimulating a larger skin area to provide more information concurrently and modulate parameters spatially as well as in amplitude. However, for effective use, electrotactile stimulation needs to be calibrated and it would be convenient to perform this procedure while the subject is seated. However, amplitude and spatial perception can be affected by motion and/or physical coupling between the residual limb and the socket. In the present study, we therefore evaluated and compared the psychometric properties of multichannel electrotactile stimulation applied to the thigh/residual limb during sitting versus walking. METHODS: The comprehensive assessment included the measurement of the sensation and discomfort thresholds (ST & DT), just noticeable difference (JND), number of distinct intervals (NDI), two-point discrimination threshold (2PD), and spatial discrimination performance (SD). The experiment involved 11 able-bodied participants (4 females and 7 males; 29.2 ± 3.8 years), 3 participants with transtibial amputation, and 3 participants with transfemoral amputation. RESULTS: In able-bodied participants, the results were consistent for all the measured parameters, and they indicated that both amplitude and spatial perception became worse during walking. More specifically, ST and DT increased significantly during walking vs. sitting (2.90 ± 0.82 mA vs. 2.00 ± 0.52 mA; p < 0.001 for ST and 7.74 ± 0.84 mA vs. 7.21 ± 1.30 mA; p < 0.05 for DT) and likewise for the JND (22.47 ± 12.21% vs. 11.82 ± 5.07%; p < 0.01), while the NDI became lower (6.46 ± 3.47 vs. 11.27 ± 5.18 intervals; p < 0.01). Regarding spatial perception, 2PD was higher during walking (69.78 ± 17.66 mm vs. 57.85 ± 14.87 mm; p < 0.001), while the performance of SD was significantly lower (56.70 ± 10.02% vs. 64.55 ± 9.44%; p < 0.01). For participants with lower-limb amputation, the ST, DT, and performance in the SD assessment followed the trends observed in the able-bodied population. The results for 2PD and JND were however different and subject-specific. CONCLUSION: The conducted evaluation demonstrates that electrotactile feedback should be calibrated in the conditions in which it will be used (e.g., during walking). The calibration during sitting, while more convenient, might lead to an overly optimistic (or in some cases pessimistic) estimate of sensitivity. In addition, the results underline that calibration is particularly important in people affected by lower-limb loss to capture the substantial variability in the conditions of the residual limb and prosthesis setup. These insights are important for the implementation of artificial sensory feedback in lower-limb prosthetics applications.

A scoping review of eye tracking metrics used to assess visuomotor behaviours of upper limb prosthesis users.

Advanced upper limb prostheses aim to restore coordinated hand and arm function. However, this objective can be difficult to quantify as coordinated movements require an intact visuomotor system. Eye tracking has recently been applied to study the visuomotor behaviours of upper limb prosthesis users by enabling the calculation of eye movement metrics. This scoping review aims to characterize the visuomotor behaviours of upper limb prosthesis users as described by eye tracking metrics, to summarize the eye tracking metrics used to describe prosthetic behaviour, and to identify gaps in the literature and potential areas for future research. A review of the literature was performed to identify articles that reported eye tracking metrics to evaluate the visual behaviours of individuals using an upper limb prosthesis. Data on the level of amputation, type of prosthetic device, type of eye tracker, primary eye metrics, secondary outcome metrics, experimental task, aims, and key findings were extracted. Seventeen studies were included in this scoping review. A consistently reported finding is that prosthesis users have a characteristic visuomotor behaviour that differs from that of individuals with intact arm function. Visual attention has been reported to be directed more towards the hand and less towards the target during object manipulation tasks. A gaze switching strategy and delay to disengage gaze from the current target has also been reported. Differences in the type of prosthetic device and experimental task have revealed some distinct gaze behaviours. Control factors have been shown to be related to gaze behaviour, while sensory feedback and training interventions have been demonstrated to reduce the visual attention associated with prosthesis use. Eye tracking metrics have also been used to assess the cognitive load and sense of agency of prosthesis users. Overall, there is evidence that eye tracking is an effective tool to quantitatively assess the visuomotor behaviour of prosthesis users and the recorded eye metrics are sensitive to change in response to various factors. Additional studies are needed to validate the eye metrics used to assess cognitive load and sense of agency in upper limb prosthesis users.

A Workflow for Studying the Stump-Socket Interface in Persons with Transtibial Amputation through 3D Thermographic Mapping.

The design and fitting of prosthetic sockets can significantly affect the acceptance of an artificial limb by persons with lower limb amputations. Clinical fitting is typically an iterative process, which requires patients' feedback and professional assessment. When feedback is unreliable due to the patient's physical or psychological conditions, quantitative measures can support decision-making. Specifically, monitoring the skin temperature of the residual limb can provide valuable information regarding unwanted mechanical stresses and reduced vascularization, which can lead to inflammation, skin sores and ulcerations. Multiple 2D images to examine a real-life 3D limb can be cumbersome and might only offer a partial assessment of critical areas. To overcome these issues, we developed a workflow for integrating thermographic information on the 3D scan of a residual limb, with intrinsic reconstruction quality measures. Specifically, workflow allows us to calculate a 3D thermal map of the skin of the stump at rest and after walking, and summarize this information with a single 3D differential map. The workflow was tested on a person with transtibial amputation, with a reconstruction accuracy lower than 3 mm, which is adequate for socket adaptation. We expect the workflow to improve socket acceptance and patients' quality of life.

Development of overuse musculoskeletal conditions after combat-related upper limb amputation: a retrospective cohort study.

STUDY DESIGN: Retrospective cohort study INTRODUCTION: Service members who have sustained traumatic amputations are typically young and otherwise healthy. Beyond standard care, these individuals desire long, highly active, and relatively pain-free lifestyle, whether that is returning to active duty or transitioning to civilian life. Development of overuse musculoskeletal conditions could have a significant influence on quality of life for Service members with traumatic upper limb amputation. PURPOSE OF THE STUDY: Compare one-year incidence of overuse musculoskeletal injuries in Service members with different levels of combat-related upper limb amputation to Service members with minor combat-related upper limb injuries. METHODS: Service members with deployment-related upper limb injury (N = 519), 148 major upper limb amputation (55 with amputation at or above elbow, 93 with amputation below elbow) and 371 minor upper limb injury were included in the study. Outcomes of interest clinical diagnosis codes associated with overuse conditions of the upper limb, neck and upper back, lower limb, low back pain, and all regions combined, one year before and one year after injury. RESULTS: Overall, the one-year incidence of developing at least one musculoskeletal overuse condition after upper limb amputation was between 60% and 65%. Service members with upper limb amputations were 2.7 to 4.7 times more likely to develop an overuse upper limb condition, 3.6 to 3.8 times more likely to develop a neck and upper back condition, 2.8 to 4.4 times more likely to develop a lower limb condition, and 3.3 to 3.9 times more likely to develop low back pain as compared those who sustained minor combat-related injuries. No significant differences in the odds of developing a musculoskeletal condition was found between the above elbow and below elbow amputation groups. CONCLUSIONS: Incidence of secondary overuse conditions is elevated in Service members with upper limb amputation and warrants focused research efforts toward preventative and rehabilitative interventions.

[Serum creatine phosphokinase as a predictor of upper limb amputation in electrical trauma]. / Soderzhanie kreatinfosfokinazy v plazme krovi kak prediktor amputatsii verkhnei konechnosti pri elektrotravme.

OBJECTIVE: To study the relationship between serum creatine phosphokinase and outcomes of injury in victims with electrical burns. MATERIAL AND METHODS: Among 40 patients with electrical injury, 7 (18%) ones underwent upper limb amputation. There were 37 (92.5%) men and 3 (7.5%) women aged 37 (28; 47) years. We analyzed total serum creatine phosphokinase and MB fraction on the first day in patients with and without amputations. RESULTS: Total serum creatine phosphokinase exceeded the upper reference value in 11 out of 33 patients without amputation and in all 7 patients with limb amputation (p=0.001). Patients with limb amputation had significantly higher total serum creatine phosphokinase and MB fraction (p<0.001 and p=0.030, respectively). Logistic regression equation showed that high total serum creatine phosphokinase significantly influenced amputation rate (p<0.001), as evidenced by odds ratio (42.7, 95% CI 3.5-514.8). ROC analysis revealed the cut-off value of total serum creatine phosphokinase (950 IU/L). Sensitivity was 100% (63; 100), specificity - 94% (86; 94), positive predictive value - 78% (49; 78), negative predictive value - 100% (92; 100). CONCLUSION: Total serum creatine phosphokinase depends only on severity of electrical and flame burns. Serum creatine phosphokinase is a predictor of upper limb amputation in patients with electrical injury. Total serum creatine phosphokinase ≥ 950 IU/L is significant for upper limb amputation (in CK-MB fraction within the reference values).