Cortical Reorganization after Limb Loss: Bridging the Gap between Basic Science and Clinical Recovery.

Despite the increasing incidence and prevalence of amputation across the globe, individuals with acquired limb loss continue to struggle with functional recovery and chronic pain. A more complete understanding of the motor and sensory remodeling of the peripheral and central nervous system that occurs postamputation may help advance clinical interventions to improve the quality of life for individuals with acquired limb loss. The purpose of this article is to first provide background clinical context on individuals with acquired limb loss and then to provide a comprehensive review of the known motor and sensory neural adaptations from both animal models and human clinical trials. Finally, the article bridges the gap between basic science researchers and clinicians that treat individuals with limb loss by explaining how current clinical treatments may restore function and modulate phantom limb pain using the underlying neural adaptations described above. This review should encourage the further development of novel treatments with known neurological targets to improve the recovery of individuals postamputation.Significance Statement In the United States, 1.6 million people live with limb loss; this number is expected to more than double by 2050. Improved surgical procedures enhance recovery, and new prosthetics and neural interfaces can replace missing limbs with those that communicate bidirectionally with the brain. These advances have been fairly successful, but still most patients experience persistent problems like phantom limb pain, and others discontinue prostheses instead of learning to use them daily. These problematic patient outcomes may be due in part to the lack of consensus among basic and clinical researchers regarding the plasticity mechanisms that occur in the brain after amputation injuries. Here we review results from clinical and animal model studies to bridge this clinical-basic science gap.

Shake it off: exploring drivers and outcomes of autotomy in marine invertebrates.

Autotomy refers to self-amputation where the loss of a limb or organ is generally said to be (1) in response to stressful external stimuli; (2) voluntary and nervously mediated; (3) supported by adaptive features that increase efficiency and simultaneously mediate the cost; and (4) morphologically delineated by a predictable breakage plane. It is estimated that this phenomenon has evolved independently nine different times across the animal kingdom, appearing in many different taxa, including vertebrate and invertebrate as well as aquatic and terrestrial animals. Marine invertebrates use this behaviour in a diversity of manners that have yet to be globally reviewed and critically examined. Here, published data from marine invertebrate taxa were used to explore instances of injury as an evolutionary driver of autotomy. Findings suggest that phyla (e.g. Echinodermata and Arthropoda) possibly experiencing high rates of injury (tissue damage or loss) are more likely to be able to perform autotomy. Additionally, this review looks at various morphological, physiological and environmental conditions that have either driven the evolution or maintained the behaviour of autotomy in marine invertebrates. Finally, the use of autotomic abilities in the development of more sustainable and less ecologically invasive fisheries is explored.

Utilization and Perception of Peer-Support After Lower Limb Loss in the United States: Potential Benefits on Mobility Outcomes.

OBJECTIVE: To examine participants' experiences with peer-support after lower limb loss (LLL) and the associations between the peer-support experience (perceived benefits and barriers) and mobility outcomes. DESIGN: Quantitative and qualitative descriptive study with a cross-sectional design. SETTING: National survey (distributed to 169 peer-support groups in 44 states in the US). PARTICIPANTS: The survey was completed by 82 individuals with a major lower limb amputation (53% female, 54% over 55 years of age; N=82). MAIN OUTCOME MEASURES: A 32-item survey to examine respondents' experiences in peer-support activities. Prosthetic mobility was measured using the Prosthetic Limb Users Survey of Mobility (PLUS-M). RESULTS: Two out of 3 respondents received some forms of peer-support after amputation. Among them 75% reported peer-support having a positive effect on their outlook on life, and 78% reported that information gained from peer-support was helpful. Companionship, altruistic acts, and gaining information on how to cope with amputation were the top themes of why respondents enjoyed the peer-support experience. Nearly all (94%) respondents would recommend peer-support to other people with LLL. Individuals who received peer-support exhibited a trend of greater mobility (55th vs 36th percentile on PLUS-M; P=.055). CONCLUSION: Individuals with LLL reported generally positive experiences regarding their engagement in peer-support activities. Peer-support groups are viewed as a helpful source for both information and emotional support, potentially benefiting functional and psychological recovery after amputation. Individuals who have received peer-support also exhibited greater mobility.

Pharmacomechanical thrombectomy with Angiojet in acute arterial occlusions: A prospective study among the results and outcomes.

OBJECTIVE: The main objective of this present paper was to evaluate the results and outcomes of patients with acute limb ischemia (ALI) submitted to pharmacomechanical thrombectomy (PMT) endovascular surgery with Angiojet, regarding the number of cycles/pumps. METHODS: Prospective, consecutive cohort study of ALI patients submitted to PMT endovascular intervention subdivided into two groups according to the number of cycles in the Angiojet technique: Group 1 higher than 150 cycles/second and Group 2 lesser than 150 cycles/second (cycles/s). RESULTS: Overall, 92 patients with ALI submitted to PMT were evaluated. Two groups of patients were identified: Group 1 higher than 150 cycles/s with 60 patients and Group 2 lesser than 150 cycles/s with 32 patients. The overall mortality rate (OMR) was 15.1% (13 patients) in total cohort within the first 30 days. Group 1 had a higher OMR than Group 2 (16.1% vs 9.3%, p = 0.007). There were 4 cases of hematuria (4.3%), all of them in Group 1. We have performed a Kaplan-Meier regarding limb salvage rates: Group 1 had 85% and Group 2 had 95.7% at 1057 days. P = 0.081. Among the factors evaluated, the following were related to overall mortality rate: PMT with higher >150 cycles/s (HR = 7.17, p = 0.007, CI: 1.38-8.89), COVID-19 infection (HR = 2.75, p = 0.010, CI = 1.73-5.97), and post-operative acute kidney injury (HR = 2.97, p < 0.001, CI = 1.32-8.13). Among the factors evaluated, the following was related to limb loss: post-operative acute kidney injury (HR = 4.41, p = 0.036, CI: 1.771-7.132), probably because patients experiencing limb loss have a higher incidence of acute renal insufficiency due to higher circulating myoglobin higher hemolysis from the increased Angiojet cycles inducing rhabdomyolysis. CONCLUSION: PMT with Angiojet is a safe and effective therapy in patients with ALI. However, patients receiving greater than 150 cycles/s were noted to have higher rates of acute kidney injury and mortality. This is likely reflective of increased thrombus burden and higher rates of hemolysis. Acute kidney injury, greater than 150 cycles/s, and COVID-19 infection were the variables with the strongest association to perioperative mortality.

Building a Multidisciplinary Clinic Dedicated to Upper-Extremity Limb Loss.

Complete care of the patient with upper limb loss mandates a long-term, multifaceted approach. Increased functionality and quality of life require collaborative efforts between the patient's surgeon, prosthetist, hand therapists, mental health professionals, and peers. An individual surgeon may find that initiating and maintaining a practice offering total integrated treatment for upper-extremity amputees is a formidable task, but with specific, actionable recommendations, the process can be demystified. The upper-extremity surgeon must be facile with operative techniques such as targeted muscle reinnervation (TMR), regenerative peripheral nerve interface (RPNI), and soft tissue reconstruction and focus on team recruitment strategy and promotion of the clinic within the community. Consistent communication and team decision-making shape each patient's preoperative and postoperative course. We aim to relay effective interventions at each step of recovery from each clinic member and describe clinic workflow designed to reinforce holistic care. We present a blueprint for creating a functional and comprehensive multidisciplinary center for patients with upper-extremity limb loss for those providers interested in providing care, but who are missing the logistical roadmap for how to do so.

Accuracy, Repeatability, and Reproducibility of a Hand-Held Structured-Light 3D Scanner across Multi-Site Settings in Lower Limb Prosthetics.

The aim of this work was to assess the accuracy, repeatability, and reproducibility of a hand-held, structured-light 3D scanner (EINScan Pro 2X Plus with High Definition Prime Pack, SHINING 3D Tech. Co., Ltd., Hangzhou, China), to support its potential use in multi-site settings on lower limb prosthetics. Four limb models with different shapes were fabricated and scanned with a metrological 3D scanner (EINScan Laser FreeScan 5X, SHINING 3D Tech. Co., Ltd., Hangzhou, China) by a professional operator (OP0). Limb models were then mailed to three sites where two operators (OP1, OP2) scanned them using their own structured-light 3D scanner (same model). OP1 scanned limb models twice (OP1-A, OP1-B). OP0, OP1-A, and OP2 scans were compared for accuracy, OP1-A and OP1-B for repeatability, and OP1-A and OP2 for reproducibility. Among all comparisons, the mean radial error was <0.25 mm, mean angular error was <4°, and root mean square error of the radial distance was <1 mm. Moreover, limits of agreement were <3.5% for perimeters and volumes. By comparing these results with respect to clinically-relevant thresholds and to the literature available on other 3D scanners, we conclude that the EINScan Pro 2X Plus 3D Scanner with High Definition Prime Pack has good accuracy, repeatability, and reproducibility, supporting its use in multi-site settings.

Hip joint and muscle loading for persons with bilateral transfemoral/through-knee amputations: biomechanical differences between full-length articulated and foreshortened non-articulated prostheses.

BACKGROUND: Currently, there is little available in-depth analysis of the biomechanical effect of different prostheses on the musculoskeletal system function and residual limb internal loading for persons with bilateral transfemoral/through-knee amputations (BTF). Commercially available prostheses for BTF include full-length articulated prostheses (microprocessor-controlled prosthetic knees with dynamic response prosthetic feet) and foreshortened non-articulated stubby prostheses. This study aims to assess and compare the BTF musculoskeletal function and loading during gait with these two types of prostheses. METHODS: Gait data were collected from four male traumatic military BTF and four able-bodied (AB) matched controls using a 10-camera motion capture system with two force plates. BTF completed level-ground walking trials with full-length articulated and foreshortened non-articulated stubby prostheses. Inverse kinematics, inverse dynamics and musculoskeletal modelling simulations were conducted. RESULTS: Full-length articulated prostheses introduced larger stride length (by 0.5 m) and walking speed (by 0.3 m/s) than stubbies. BTF with articulated prostheses showed larger peak hip extension angles (by 10.1°), flexion moment (by 1.0 Nm/kg) and second peak hip contact force (by 3.8 bodyweight) than stubbies. There was no difference in the hip joint loading profile between BTF with stubbies and AB for one gait cycle. Full-length articulated prostheses introduced higher hip flexor muscle force impulse than stubbies. CONCLUSIONS: Compared to stubbies, BTF with full-length articulated prostheses can achieve similar activity levels to persons without limb loss, but this may introduce detrimental muscle and hip joint loading, which may lead to reduced muscular endurance and joint degeneration. This study provides beneficial guidance in making informed decisions for prosthesis choice.

Body image and psychosocial well-being among UK military personnel and veterans who sustained appearance-altering conflict injuries.

A modest but significant number of military personnel sustained injuries during deployments resulting in an altered-appearance (e.g., limb loss and/or scarring). Civilian research indicates that appearance-altering injuries can affect psychosocial wellbeing, yet little is known about the impact of such injuries among injured personnel. This study aimed to understand the psychosocial impact of appearance-altering injuries and possible support needs among UK military personnel and veterans. Semi-structured interviews with 23 military participants who sustained appearance-altering injuries during deployments or training since 1969 were conducted. The interviews were analyzed using reflexive thematic analysis, identifying six master themes. These themes indicate that in the context of broader recovery experiences, military personnel and veterans experience a variety of psychosocial difficulties related to their changed appearance. While some of these are consistent with evidence from civilians, military-related nuances in the challenges, protective experiences, coping approaches, and preferences for support are evident. Personnel and veterans with appearance-altering injuries may require specific support for adjusting to their changed appearance and related difficulties. However, barriers to acknowledging appearance concerns were identified. Implications for support provision and future research are discussed.

A review of musculoskeletal adaptations in individuals following major lower-limb amputation.

Structural musculoskeletal adaptations following amputation, such as bone mineral density (BMD) or muscle architecture, are often overlooked despite their established contributions to gait rehabilitation and the development of adverse secondary physical conditions. The purpose of this review is to provide a summary of the existing literature investigating musculoskeletal adaptations in individuals with major lower-limb amputations to inform clinical practice and provide directions for future research. Google Scholar, PubMed, and Scopus were searched for original peer-reviewed studies that included individuals with transtibial or transfemoral amputations. Summary data of twenty-seven articles indicated reduced BMD and increased muscle atrophy in amputees compared to controls, and in the amputated limb compared to intact and control limbs. Specifically, BMD was reduced in T-scores and Z-scores, femoral neck, and proximal tibia. Muscle atrophy was evidenced by decreased thigh cross-sectional area, decreased quadriceps thickness, and increased amounts of thigh fat. Overall, amputees have impaired musculoskeletal health. Future studies should include dysvascular etiologies to address their effects on musculoskeletal health and functional mobility. Moreover, clinicians can use these findings to screen increased risks of adverse sequelae such as fractures, osteopenia/porosis, and muscular atrophy, as well as target specific rehabilitation exercises to reduce these risks.

Traumatic Lower Extremity Vascular Injuries and Limb Salvage in a Civilian Urban Trauma Center.

BACKGROUND: Data on management of traumatic lower extreity arterial injuries comes largely from military experience and involves few civilian centers. This study reports on the experience of an urban trauma center and factors associated with limb loss. METHODS: A retrospective review of lower extremity arterial injuries between 2013 and 2020 at an academic urban level 1 trauma center was completed. Patients with lower extremity revascularization were included in the final data analysis. Demographics, clinical variables, operative details, type of revascularization, as well as 30-day morbidity and postoperative outcomes were analyzed. The primary outcome of interest was 30-day limb loss. Secondary outcomes included postoperative complications and functional outcomes. RESULTS: Seventy-five patients were included in our analysis. Sixty-nine were male (92%), mean age 33 ± 15 years, 50 patients had penetrating trauma (67%), mean injury severity score was 15 ± 9. Thirty-day limb loss was reported in 8 (11%). Factors associated with limb loss included female sex (P = 0.001), high body mass index (P = 0.001), blunt injury (P = 0.001), associated fractures (P = 0.005), significant soft tissue injury (P = 0.007), delayed repair after shunt placement (P = 0.003), bypass revascularization (P = 0.001), initial revascularization failure (P = 0.019), and wound complications (P < 0.001). Fifty-five patients had at least one return to the operating room (ROR), including 24 patients (32%) for complications related to their revascularization. These included delayed compartment syndrome (n = 7), revascularization failure (n = 9), bleeding (n = 3), and vascular surgical wound complications (n = 5). Mean length of hospital stay (LOS) for the cohort was 24 ± 20 days with 3 ± 3 ROR, in contrast patients who ultimately required amputation had LOS of 57 ± 21 days with 8 ± 4 ROR. Fifty-seven patients (76%) followed in clinic for a median 36 [14-110] days, with only 32 (43%) at >30 days. Twenty-three reported ambulation without assistance, 9 neuromotor deficit including 1 patient that had delayed amputation. CONCLUSION: Patients with blunt trauma and associated fracture and/or extensive soft tissue injury are at risk of limb loss. These injuries are often associated with postoperative wound complications, requiring aggressive soft tissue care that substantially increases ROR and LOS; Expectations for limb salvage in these patients should be tempered when the other associated factors with limb loss mentioned above are also present. When limb salvage is achieved, regaining full limb function remains a challenge.

Investigating the Effect of Real-Time Center of Pressure Feedback Training on the Swing Phase of Lower Limb Kinematics in Transfemoral Prostheses With SACH Foot.

Transfemoral amputee often encounters reduced toe clearance resulting in trip-related falls. Swing-phase joint angles have been shown to influence the toe clearance; therefore, training intervention that targets shaping the swing phase joint angles can potentially enhance toe clearance. The focus of this study was to investigate the effect of the shift in the location of the center of pressure (CoP) during heel strike on modulation of the swing-phase joint angles in able-bodied participants (n = 6) and transfemoral amputees (n = 3). We first developed a real-time CoP-based visual feedback system such that participants could shift the CoP during treadmill walking. Next, the kinematic data were collected during two different walking sessions-baseline (without feedback) and feedback (shifting the CoP anteriorly/posteriorly at heel strike to match the target CoP location). Primary swing-phase joint angle adaptations were observed with feedback such that during the midswing phase, posterior CoP shift feedback significantly increases (p < 0.05) the average hip and knee flexion angle by 11.55 deg and 11.86 deg, respectively, in amputees, whereas a significant increase (p < 0.05) in ankle dorsiflexion, hip and knee flexion angle by 3.60 deg, 3.22 deg, and 1.27 deg, respectively, compared to baseline was observed in able-bodied participants. Moreover, an opposite kinematic adaptation was seen during anterior CoP shift feedback. Overall, results confirm a direct correlation between the CoP shift and the modulation in the swing-phase lower limb joint angles.

Plasma concentrations of lipoproteins and risk of lower-limb peripheral artery disease in people with type 2 diabetes: the SURDIAGENE study.

AIMS/HYPOTHESIS: The lipid profile has not been fully investigated in individuals with peripheral artery disease (PAD). We aimed to evaluate the relationship between plasma concentrations of lipoproteins and the prevalence of lower-limb PAD at baseline and its incidence during follow-up in people with type 2 diabetes. METHODS: Plasma concentrations of total cholesterol, HDL-cholesterol, triacylglycerol and apolipoprotein (Apo) A-I, ApoA-II, ApoB-100 and Apo(a) were measured at baseline using colorimetric or MS methods in the SURDIAGENE cohort. Total cholesterol/HDL-cholesterol ratio, non-HDL-cholesterol and LDL-cholesterol were estimated using computation formulas. Logistic and Cox proportional hazard regression models were fitted to estimate OR or HR, with related 95% CI, for baseline prevalence or incidence of major PAD (lower-limb amputation or requirement of revascularisation) during follow-up by increasing lipoprotein tertiles, after adjustment for key confounders. RESULTS: Among 1468 participants (women 42%, mean ± SD age 65 ± 11 years, duration of diabetes 14 ± 10 years at baseline), 129 (8.8%) had a baseline history of major PAD. Major PAD was less prevalent at baseline in the highest (vs lowest) tertile of HDL-cholesterol (OR 0.42 [95% CI 0.26, 0.71], p = 0.001) and ApoA-I (OR 0.39 [95% CI 0.23, 0.67], p = 0.0007), and more frequent in the highest tertile of total cholesterol/HDL-cholesterol ratio (OR 1.95 [95% CI 1.18, 3.24], p = 0.01). Among 1339 participants without a history of PAD at baseline, incident PAD occurred in 97 (7.2%) during a median (25th-75th percentile) duration of follow-up of 7.1 (4.4-10.7) years, corresponding to 9685 person-years and an incidence rate of 9.8 (95% CI 8.0, 12.0) per 1000 person-years. The risk of incident PAD was lower in the top (vs bottom) tertile of HDL-cholesterol (HR 0.54 [95% CI 0.30, 0.95], p = 0.03) or ApoA-I (HR 0.50 [95% CI 0.28, 0.86], p = 0.01) and higher in the top tertile of total cholesterol/HDL-cholesterol ratio (HR 2.81 [95% CI 1.61, 5.04], p = 0.0002) and non-HDL-cholesterol (HR 1.80 [95% CI 1.06, 3.12], p = 0.03). CONCLUSIONS/INTERPRETATION: We reported independent associations between HDL-cholesterol, ApoA-I, total cholesterol/HDL-cholesterol ratio or non-HDL-cholesterol and the prevalence or the incidence of major PAD in people with type 2 diabetes. Our findings provide a picture of lipoprotein profile in people with type 2 diabetes. Graphical abstract.

Cortical representations of phantom movements in lower limb amputees.

Understanding how sensorimotor cortex (SMC) organization relates to limb loss has major clinical implications, as cortical activity associated with phantom hand movements has been shown to predict phantom pain reports. Critically, earlier studies have largely focused on upper limb amputees; far less is known regarding SMC activity in lower limb amputees, despite the fact that this population comprises the majority of major limb loss cases. We aimed to characterize BOLD fMRI responses associated with phantom and sound limb movements to test the hypothesis that SMC organization is preserved in individuals with lower limb loss. Individuals with unilateral or bilateral lower limb loss underwent fMRI scans as they performed simple movements of their sound or phantom limbs. We observed that voluntary movements of the sound and phantom ankles were associated with BOLD signal changes in medial and superior portions of the precentral and postcentral gyri. In both hemispheres, contralateral limb movements were associated with greater signal changes compared to ipsilateral limb movements. Hand and mouth movements were associated with distinct activation patterns localized to more lateral SMC regions. We additionally tested whether activations associated with phantom movements related to self-report assessments indexing phantom pain experiences, nonpainful phantom sensations and phantom movement capabilities. We found that responses during phantom ankle movements did not correlate with any of the composite phantom limb indices in our sample. Our collective results reveal that SMC representations of the amputated limb persist and that traditional somatotopic organization is generally preserved in individuals suffering from lower limb loss.

Autotomy-induced effects on the locomotor performance of the ghost crab Ocypode quadrata.

The voluntary amputation of an appendage, or autotomy, is an effective defensive mechanism that allows an animal to escape aggressive interactions. However, animals may suffer long-term costs that can reduce their overall fitness. Atlantic ghost crabs (Ocypode quadrata) are one of the fastest terrestrial invertebrates, and regularly lose one or more limbs in response to an antagonist encounter. When running laterally at fast speeds, they adopt a quadrupedal gait using their first and second pairs of legs while raising their fourth, and sometimes the third, pair of legs off the ground. This suggests that some limbs may be more important for achieving maximal locomotor performance than others. The goal of this study was to determine whether the loss of certain limbs would affect running performance more than others, and what compensatory strategies were used. Crabs were assigned to four different paired limb removal treatments or the control group and run on an enclosed trackway in their natural habitat. Ghost crabs were found to adjust stride kinematics in response to limb loss. Loss of the second or third limb pairs caused a reduction in running speed by about 25%, suggesting that the remaining intact limbs were unable to compensate for the loss of either limb, either due to a lack of propulsive forces produced by these limbs or issues stemming from re-coupling limb arrangements. Loss of any of the other limbs had no detectable effect on running speed. We conclude that compensatory ability varies depending on the limb that is lost.

Trunk Postural Control Strategies Among Persons With Lower-Limb Amputation While Walking and Performing a Concurrent Task.

Altered trunk movements during gait in persons with lower-limb amputation are often associated with an increased risk for secondary health conditions; however, the postural control strategies underlying such alterations remain unclear. In this secondary analysis, the authors employed nonlinear measures of triplanar trunk accelerations via short-term Lyapunov exponents to investigate trunk local stability as well as spatiotemporal gait parameters to describe gait mechanics. The authors also evaluated the influence of a concurrent task on trunk local stability and gait mechanics to explore if competition for neuromuscular processing resources can assist in identifying unique strategies to control kinematic variability. Sixteen males with amputation-8 transtibial and 8 transfemoral-and 8 uninjured males (controls) walked on a treadmill at their self-selected speed (mean = 1.2 m/s ±10%) in 5 experimental conditions (8 min each): 4 while performing a concurrent task (2 walking and 2 seated) and 1 with no concurrent task. Individuals with amputation demonstrated significantly smaller Lyapunov exponents than controls in all 3 planes of motion, regardless of concurrent task or level of amputation (P < .0001). Individuals with transfemoral amputation walked with wider strides compared with individuals with transtibial amputation and controls (P < .0001). Individuals with amputation demonstrated more trunk kinematic variability in the presence of wider strides compared with individuals without amputation, and it appears that performing a concurrent cognitive task while walking did not change trunk or gait mechanics.

Characterizing and Understanding the Low Back Pain Experience Among Persons with Lower Limb Loss.

OBJECTIVE: This study preliminarily characterizes and compares the impact of lower limb loss and development of chronic low back pain (cLBP) on psychosocial factors, as well as the relationship between these factors and low back pain-related functional disability. DESIGN: Cross-sectional study. METHODS: Participants were adults, active duty or retired military, with traumatic lower limb loss with and without chronic low back pain. Psychosocial factors and low back pain-related functional disability were measured using common clinical self-report questionnaires. The presence of psychosocial factors was compared between those with and without cLBP using multivariate analysis of covariance (P < 0.05), and correlations determined relationships between psychosocial factors and cLBP-related functional disability. RESULTS: There were no statistically significant differences among psychosocial factors between those with vs without cLBP (F(4, 13) = 0.81, P = 0.54, η2= 0.19). Employment status (ρ = 0.43, P = 0.02), anxiety (ρ = 0.45, P = 0.04), and kinesiophobia (ρ = 0.47, P = 0.04) were moderately associated with low back pain-related disability. CONCLUSIONS: Psychological (i.e., anxiety) and social (i.e., employment status) factors may influence how persons with traumatic lower limb loss respond to self-reported measures of low back pain-related disability. The findings suggest that the Modified Oswestry Disability Index identifies cLBP-related functional disability in the context of lower limb loss. These results support the interdependence among biological, psychological, and social factors, which should be collectively considered during the development of rehabilitative strategies to treat secondary musculoskeletal conditions within this population.

Biomechanical and neurocognitive performance outcomes of walking with transtibial limb loss while challenged by a concurrent task.

Individuals who have sustained loss of a lower limb may require adaptations in sensorimotor and control systems to effectively utilize a prosthesis, and the interaction of these systems during walking is not clearly understood for this patient population. The aim of this study was to concurrently evaluate temporospatial gait mechanics and cortical dynamics in a population with and without unilateral transtibial limb loss (TT). Utilizing motion capture and electroencephalography, these outcomes were simultaneously collected while participants with and without TT completed a concurrent task of varying difficulty (low- and high-demand) while seated and walking. All participants demonstrated a wider base of support and more stable gait pattern when walking and completing the high-demand concurrent task. The cortical dynamics were similarly modulated by the task demand for both groups, to include a decrease in the novelty-P3 component and increase in the frontal theta/parietal alpha ratio power when completing the high-demand task, although specific differences were also observed. These findings confirm and extend prior efforts indicating that dual-task walking can negatively affect walking mechanics and/or neurocognitive performance. However, there may be limited additional cognitive and/or biomechanical impact of utilizing a prosthesis in a stable, protected environment in TT who have acclimated to ambulating with a prosthesis. These results highlight the need for future work to evaluate interactions between these cognitive-motor control systems for individuals with more proximal levels of lower limb loss, and in more challenging (ecologically valid) environments.

Humerus fracture and combined venous injury increases limb loss in axillary or subclavian artery injury.

OBJECTIVE: Axillosubclavian vessel injury is rare, with most cases occurring after penetrating trauma. A prior database (2002-2006) analysis demonstrated an overall limb loss rate of 2.9%, with no difference between isolated arterial axillosubclavian vessel injury and combined artery/vein axillosubclavian vessel injury. Given increases in advanced vascular surgical techniques, as well as improved multidisciplinary care and expeditious diagnosis with computed tomography angiography, we hypothesized the national rate of limb loss in patients with arterial axillosubclavian vessel injury has decreased. In addition, we attempted to identify current predictors for limb loss in arterial axillosubclavian vessel injury. Finally, we hypothesized that combined artery/vein axillosubclavian vessel injury, as well as associated brachial plexus injury will have a higher risk for limb-loss and mortality compared to isolated arterial axillosubclavian vessel injury. METHODS: A retrospective analysis of the National Trauma Data Bank was performed between 2007 and 2015. All patients ≥ 18 years of age with arterial axillosubclavian vessel injury were included. The primary outcome was limb loss. After a univariable logistic regression model identified significant covariates, we performed a multivariable logistic regression for analysis. RESULTS: Of the total 5,494,609 trauma admissions, 3807 patients had arterial axillosubclavian vessel injury (<0.1%). Of these, 3137 (82.4%) had isolated arterial axillosubclavian vessel injury and 670 (17.6%) had combined artery/vein axillosubclavian vessel injury. The overall limb loss rate was 2.4% (from 2.9% in 2006, p = 0.47). After adjusting for covariates, independent risk factors for limb loss included a combined artery/vein axillosubclavian vessel injury (odds ratio = 3.54, confidence interval = 2.06-6.11, p < 0.001), blunt mechanism (odds ratio = 7.81, confidence interval = 4.21-14.48, p < 0.001), open repair (odds ratio = 2.37, confidence interval = 1.47-3.82, p < 0.001), and open proximal humerus fracture (odds ratio = 8.50, confidence interval = 4.97-14.54, p < 0.001). An associated brachial plexus injury was not associated with limb loss ( p = 0.37). Combined artery/vein axillosubclavian vessel injury was associated with higher risk for mortality compared to isolated arterial axillosubclavian vessel injury (odds ratio = 2.17, confidence interval = 1.73-2.71, p < 0.001). CONCLUSIONS: The national rate of limb loss in trauma patients with arterial axillosubclavian vessel injury has not changed in the past decade. A combined artery/vein axillosubclavian vessel injury is an independent risk factor for limb loss, as well as open repair. However, the strongest risk factor is an open proximal humerus fracture. An associated brachial plexus injury is not associated with increased risk of limb loss. Patients with combined artery/vein axillosubclavian vessel injury have a twofold increased risk of death compared to patients with isolated arterial axillosubclavian vessel injury.

Why do patients with limb ischaemia present late to a vascular surgeon? A prospective cohort study from the developing world.

OBJECTIVE: To look into the factors responsible for delay in presentation of Iimb ischemia patients to a vascular surgeon. Methods: The prospective cohort study was conducted at the Aga Khan University Hospital, Karachi, from October 01, 2016, to August 10, 2018. Patients coming with delayed presentation of both acute and chronic limb ischemia were included. All the patients were assessed by qualified vascular surgeons. SPSS 23 was used for data analysis. Results: Of the 55 patients, 33(60%) had acute and 22(40%) had chronic limb ischaemia. Mean age of acute cases was 44±23.72 years and it was 60±12.49 years for chronic cases. Overall, the commonest reason behind delay was non-referral by primary physician which was the case with 11(33.3%) patients in the acute group, and 13(59%) in the chronic group. The limb loss in the acute group was 20(60%) and 8(36%) in the chronic group.. Conclusion: Delayed presentation of patients with limb ischaemia is mainly due to non-referral. A robust campaign needs to be launched to reduce the rate of limb loss.

The role of exercise testing in predicting successful ambulation with a lower extremity prosthesis: a systematic literature review and clinical practice guideline.

BACKGROUND: Growing discontent with the k-level system for functional classification of patients with limb loss and movement of healthcare toward evidence-based practice has resulted in the need for alternative forms of functional classification and development of clinical practice guidelines to improve access to quality prosthetic interventions. The purpose of this project was to develop and present a clinical practice recommendation for exercise testing in prosthetic patient care based on the results and synthesis of a systematic literature review. METHODS: Database searches of PubMed, Google Scholar, Web of Science, and Cochrane were conducted and articles reviewed. Of the potential 1386 articles 10 met the criteria for inclusion. These articles were assessed using the critical appraisal tool of the United Kingdom National Service Framework for Long-Term Conditions. Of the 10 included articles eight were of high, one of medium, and one of low, quality. Data from these articles were synthesized into 6 empirical evidence statements, all qualifying for research grade A. These statements were used to develop the proposed clinical practice guideline. RESULTS: While the results of this systematic review were not able to support the direct connection between cardiorespiratory performance and K-levels, the literature did support the ability of exercise testing results to predict successful prosthetic ambulation in some demographics. Both continuous maximum-intensity single lower extremity ergometer propelled by a sound limb and intermittent submaximal upper extremity ergometer protocols were found to be viable evaluation tools of cardiorespiratory fitness and function in the target population. CONCLUSION: The ability to sustain an exercise intensity of ≥50% of a predicted VO2max value in single leg cycle ergometry testing and achievement of a sustained workload of 30 W in upper extremity ergometry testing were found to be the strongest correlates to successful ambulation with a prosthesis. VO2 values were found to increase in amputee subjects following a 6-week exercise program. These synthesized results of the systematic literature review regarding exercise testing in patients with loss of a lower extremity were used to develop and a present a clinical treatment pathway.