Leg Volume Research Articles

Effect of the Leg Volume Change on the Performance of an Active Compression Brace Based on Shape Memory Alloys

In this paper, the effect of calf deformation on the performance of an active compression brace (ACB) due to external pressure is investigated experimentally and analytically. The ACB, actuated by shape memory alloy wires, was designed and prototyped for potentially being used in future clinical studies to prevent or mitigate symptoms of lower extremity disorders. In this work, an analytical model is presented to simulate the ACB when wrapped around a calf assumed to be either incompressible or compressible. Furthermore, a physical calf model synced with a controllable syringe pump with a LabVIEW code was used to perform cyclic tests to evaluate the performance of the ACB experimentally in both cases of having a simplified incompressible calf or, more realistically, a compressible calf. The collected experimental data was compared with simulation results obtained from the analytical model. The experimental results showed a significant drop in the actuation pressure produced by the ACB on a deformable calf model compared to an incompressible calf model. The analytical model that was developed accurately predicted such a behavior. In fact, for an initial wrapping pressure of 10 mmHg the maximum deviations between the experimental and analytical results were 1.66 and 0.54 mmHg respectively for the cases of an incompressible and compressible calf. Similarly, for the initial wrapping pressure of 15 mmHg the maximum deviations were found to be 0.52 and 0.73 mmHg respectively. A two-dimensional finite element (FE) model of the leg was also developed to investigate the effect of the applied external pressure on the internal tissue. FE analyses were conducted using different geometrical parameters of the leg including calf, tibia and fibula sizes.

Attainment of a stable, fully detached plasma state in innovative divertor configurations

A computational study of long-legged tokamak divertor configurations is performed with the edge transport code UEDGE. Several divertor configurations are considered, with radially or vertically extended, tightly baffled, outer divertor legs and with or without a secondary X-point in the divertor leg volume. For otherwise identical conditions, a scan of the input power from the core plasma is performed. As the power is reduced to a threshold value, the plasma in the outer leg transitions to a fully detached state, which defines the upper limit on the power for detached divertor operation. Reducing the power further results in the detachment front shifting upstream but remains stable. At low power, the detachment front eventually moves all the way to the primary X-point, which is usually associated with degradation of the core plasma, and this defines the lower limit on the power for the detached divertor operation. For the studied parameters, for long-legged divertors, the detached operation window is quite large, in particular, for the X-point target configuration using a secondary X-point in the divertor leg volume, allowing a factor of 5–10 variations in the input power. For the same parameters, for the standard divertor configuration, the detached operation window is very small or even non-existent. The present modeling results suggest the possibility of stable fully detached divertor operation for a tokamak with tightly baffled extended divertor legs.

LEG volume 23 issue 1 Cover and Back matter

LEG volume 23 issue 1 Cover and Back matter

LEG volume 23 issue 1 Cover and Front matter

LEG volume 23 issue 1 Cover and Front matter

Compression in the treatment of chronic venous insufficiency: Efficacy depending on the length of the stocking.

Below knee two-component compression stockings (AD) have revealed as effective for compression treatment of venous leg ulcers. Upto groin, thigh length stocking (AG) may enhance clinical effects, however wear comfort of these stocking may be affected. venous haemodynamic in relation to the length of compression stockings. A two-component AD stocking (37 mmHg) and two thigh length stockings (AG 37, with an interface pressure of 37 mmHg; AG 45, with an interface pressure of 45 mmHg) were tested by 16 patients with CVI. Leg volume changes and venous ejection fraction and venous filling index were measured, whilst quality of life and wear comfort were surveyed by questionnaires. Volume of both the lower limb and the thigh was reduced by AG stockings, whereas AD stockings reduced only the volume of the lower limb and increased thigh volume. Venous hemodynamic, ejection fraction and filling index were improved by AG and AD stockings, AG, however, was superior to AD. Quality of life and comfort of the stockings was assessed as good for AG 37 mmHg, AG 45 mmHg and AD 37 mmHg. Thigh length two component stockings (AG) were shown to be superior to below knee stocking (AD) with regard to volume reduction and venous hemodynamic, yet wear comfort was not impaired. These results imply that healing of trophic skin changes e.g. ulcers will be faster when thigh length two component stocking will be worn.

Therapeutic effects of hyaluronidase on acquired lymphedema using a newly developed mouse limb model

Acquired lymphedema is one of the most dreaded side effects of cancer treatment, such as surgical treatment or irradiation. However, due to the lack of appropriate animal models, there is no effective therapeutic method to cure acquired lymphedema. To develop a reproducible acquired lymphedema animal model, we devised a mouse hind limb model by removing a superficial inguinal lymph node, a popliteal lymph node, a deep inguinal lymph node, and the femoral lymphatic vessel. We measured the volume of lymphedematous leg and observed the change in level of hyaluronic acid (HA) and lymphangiogenic factors after injecting hyaluronidase. Our model showed the distinguishable swelling and the reliable symptoms compared to previously reported models. In the lymphedematous regions of our model, we confirmed that HA, a major component of extracellular matrix, accumulated to higher levels than in a normal mouse. This lymphedema volume was rapidly reduced by treating hyaluronidase. Following hyaluronidase injection, the lymphedematous region of our model resembled a normal hind limb. Our findings indicated that hyaluronidase promoted lymphangiogenesis on the lymphedematous limb. Based on hyaluronidase treatment in the lymphedematous region, this could potentially be a new therapeutic approach for acquired lymphedema mediated through the modification of the size of HA fragments. Impact statement In this manuscript, the essence of the work described in this manuscript involves the development of (1) a mouse limb model showing acquired lymphedema and (2) a potent therapeutic treatment using hyaluronidase to remedy acquired lymphedema in our model. In order to develop a reproducible acquired lymphedema animal model that reflects the most common symptoms experienced by lymphedema patients, we devised a mouse hind limb model by removing lymph nodes and lymphatics. Our model showed the distinguishable swelling and the reliable symptoms compared to previously reported models. In the lymphedematous regions of our model, we confirmed that hyaluronic acid (HA) accumulated to higher levels than in a normal mouse. This lymphedema volume was rapidly reduced by treating the lymphedematous leg with hyaluronidase, which also degraded high molecular weight HA to low molecular weight HA. Immunohistochemical analysis, quantitative real-time PCR analysis and lymphangioscintigraphy showed that hyaluronidase enhanced lymphangiogenesis in the lymphedematous limb.

Contribution of rostral fluid shift to intrathoracic airway narrowing in asthma.

In asthma, supine posture and sleep increase intrathoracic airway narrowing. When humans are supine, because of gravity fluid moves out of the legs and accumulates in the thorax. We hypothesized that fluid shifting out of the legs into the thorax contributes to the intrathoracic airway narrowing in asthma. Healthy and asthmatic subjects sat for 30 min and then lay supine for 30 min. To simulate overnight fluid shift, supine subjects were randomized to receive increased fluid shift out of the legs with lower body positive pressure (LBPP, 10-30 min) or none (control) and crossed over. With forced oscillation at 5 Hz, respiratory resistance (R5) and reactance (X5, reflecting respiratory stiffness) and with bioelectrical impedance, leg and thoracic fluid volumes (LFV, TFV) were measured while subjects were seated and supine (0 min, 30 min). In 17 healthy subjects (age: 51.8 ± 10.9 yr, FEV1/FVC z score: -0.4 ± 1.1), changes in R5 and X5 were similar in both study arms (P > 0.05). In 15 asthmatic subjects (58.5 ± 9.8 yr, -2.1 ± 1.3), R5 and X5 increased in both arms (ΔR5: 0.6 ± 0.9 vs. 1.4 ± 0.8 cmH2O·l-1·s-1, ΔX5: 0.3 ± 0.7 vs. 1.1 ± 0.9 cmH2O·l-1·s-1). The increases in R5 and X5 were 2.3 and 3.7 times larger with LBPP than control, however (P = 0.008, P = 0.006). The main predictor of increases in R5 with LBPP was increases in TFV (r = 0.73, P = 0.002). In asthmatic subjects, the magnitude of increases in X5 with LBPP was comparable to that with posture change from sitting to supine (1.1 ± 0.9 vs. 1.4 ± 0.9 cmH2O·l-1·s-1, P = 0.32). We conclude that in asthmatic subjects fluid shifting from the legs to the thorax while supine contributed to increases in the respiratory resistance and stiffness.NEW & NOTEWORTHY In supine asthmatic subjects, application of positive pressure to the lower body caused appreciable increases in respiratory system resistance and stiffness. Moreover, these changes in respiratory mechanics correlated positively with increase in thoracic fluid volume. These findings suggest that fluid shifts from the lower body to the thorax may contribute to overnight intrathoracic airway narrowing and worsening of asthma symptoms.

Maintenance of the Results of Stage II Lower Limb Lymphedema Treatment after Normalization of Leg Size.

Objective The aim of this study was to identify strategies to transfer responsibility of the maintenance of the results of lymphedema treatment to the patient. Methods Maintenance of the reduction of edema was evaluated in a prospective clinical trial in patients with Stage II leg lymphedema. Twenty-one lymphedematous lower limbs were evaluated in Clínica Godoy in 2014 and 2016. The evaluation was done by volumetry at baseline and weekly thereafter for volume control. Patients wore Venosan® cotton 20/30 and 30/40 mmHg elastic compression stockings followed by a custom-made inelastic stocking made of grosgrain fabric. The Friedman test for multiple comparisons and Conover post hoc test were used for statistical analysis with an alpha error of 5%. Results On comparing leg volume changes using the different types of stockings, the 20/30 mmHg elastic compression stockings failed in the first week to maintain the volume reductions but the 30/40 mmHg compression stockings did not allow significant increases in volume (p value > 0.05). During one week, the grosgrain stocking reduced leg volumes to baseline values (p value = 0.24). Conclusion Higher compression of elastic stockings is better than lower compression but the inelastic grosgrain stocking is even better than both to maintain the results.

LEG volume 22 issue 3-4 Cover and Back matter

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LEG volume 22 issue 3-4 Cover and Front matter

LEG volume 22 issue 3-4 Cover and Front matter

Circumferential suction-assisted lipectomy in the treatment of primary and secondary end-stage lymphoedema of the leg.

The treatment of end-stage lymphoedema of the leg is challenging, especially when conservative treatment fails and there is a large volume difference between the affected and unaffected legs. Circumferential suction-assisted lipectomy (CSAL) has been described as a treatment option for end-stage lymphoedema of the leg. Here, the long-term results of CSAL in end-stage primary and secondary lymphoedema of the leg were analysed. This was a descriptive study of patients treated with CSAL for unilateral chronic irreversible lymphoedema of the leg. Compression therapy was resumed after surgery. Leg volumes were measured before surgery, and at 1, 6, 12 and 24 months after the procedure. A total of 47 patients with primary lymphoedema had a median preoperative volume difference between affected and unaffected legs of 3686 (i.q.r. 2851-5121) ml. Two years after surgery, this volume difference was reduced to 761 ml, a 79 per cent reduction. In the 41 patients treated for secondary lymphoedema, the median preoperative volume difference was 3320 (i.q.r. 2533-4783) ml, decreasing after 2 years to -38 ml (101 per cent reduction). The preoperative volume difference and the sex of the patient significantly influenced the final outcome after 2 years. The outcome was not related to BMI or other patient characteristics. CSAL is an effective method for treating both primary and secondary lymphoedema of the leg.

Defying geometric similarity: Shape centralization in male UK offshore workers

Applying geometric similarity predictions of body dimensions to specific occupational groups has the potential to reveal useful ergonomic and health implications. This study assessed a representative sample of the male UK offshore workforce, and examined how body dimensions from sites typifying musculoskeletal development or fat accumulation, differed from predicted values. A cross sectional sample was obtained across seven weight categories using quota sampling, to match the wider workforce. In total, 588 UK offshore workers, 84 from each of seven weight categories, were measured for stature, mass and underwent 3D body scans which yielded 22 dimensional measurements. Each measurement was modeled using a body-mass power law (adjusting for age), to derive its exponent, which was compared against that predicted from geometric similarity. Mass scaled to stature 1.73 (CI: 1.44-2.02). Arm and leg volume increased by mass0.8 , and torso volume increased by mass1.1 in contrast to mass 1.0 predicted by geometric similarity. Neck girth increased by mass 0.33 as expected, while torso girth and depth dimensions increased by mass0.53-0.72 , all substantially greater than assumed by geometric similarity. After controlling for age, offshore workers experience spectacular "super-centralization" of body shape, with greatest gains in abdominal depth and girth dimensions in areas of fat accumulation, and relative dimensional loss in limbs. These findings are consistent with the antecedents of sarcopenic obesity, and should be flagged as a health concern for this workforce, and for future targeted research and lifestyle interventions.

Walking balance and compensatory gait mechanisms in surgically treated patients with adult spinal deformity

Background ContextGait patterns and their relationship to demographic and radiographic data in patients with adult spinal deformity (ASD) have not been fully documented. PurposeThis study aimed to assess gait pattern in patients with ASD and the effect of corrective spinal surgery on gait. Design/SettingThis is a prospective case series. Patient SampleThe gait patterns of 33 consecutive women with ASD (age 67.1 years; body mass index [BMI] 22.5±2.5 kg/m2, Cobb angle 46.8±18.2°, coronal vertical axis [CVA] 1.5±3.7 cm, C7 sagittal vertical axis [SVA] 9.1±6.4 cm, pelvic incidence minus lumbar lordosis [PI−LL] 38.2±22.1°, and lean volume of the lower leg, 5.5±0.6 kg) before and after corrective surgery were compared with those of 33 age- and gender-matched healthy volunteers. Outcome MeasuresScoliosis Research Society Patient Questionnaire (SRS22r), Oswestry Disability Index (ODI), and forceplate analysis. MethodsAll subjects underwent gait analysis on a custom-built forceplate using optical markers placed on all joints and spinal processes. Dual X-ray absorptiometry scores were used to calculate the lean composition of the lower legs. Subjects with ASD were followed for at least 2 years post operation. ResultsPreop mean values showed that patients with ASD had a significantly worse gait velocity (54±10 m/min vs. 70.7±12.9 m/min, p<.01) and stride (97.8±13.4 cm vs. 115.3±15.1 cm, p<.01), but no difference was observed in the stance-to-swing ratio. The right and left ground reaction force vectors were also discordant in the ASD group (vertical direction; r=0.84 vs. r=.97, p=.01). The hip range of motion (ROM) was also significantly decreased in ASD. Correlation coefficient showed moderate correlations between the preoperative gait velocity and the gravity line (GL), PI, ROM of the lower extremity joints, and lean volume, and between the stride and the lean volume, GL, and PI−LL. Gait pattern, stride, and velocity all improved significantly in the patients with ASD after surgery, but were still not as good as in healthy volunteers. The SRS22r satisfaction domain correlated moderately with postoperative gait velocity (r=0.34). ConclusionsThe patients with ASD had an asymmetric gait pattern and impaired gait ability compared with healthy volunteers. Gait ability correlated significantly with the GL, spinopelvic alignment, lower extremity joint ROM, and lean volume. The surgical correction of spinopelvic alignment and exercises to build muscle strength may improve the gait pattern and ability in patients with ASD.

Do No Harm, Except to Ourselves? A Survey of Symptoms and Injuries in Oncologic Surgeons and Pilot Study of an Intraoperative Ergonomic Intervention

Occupational symptoms and injuries incurred over a surgical career are under- reported, yet they have an impact on daily surgical practice. We assessed the frequency, consequences, and risk factors for occupational injury in oncologic surgeons and evaluated the feasibility of intraoperative foot mat use to mitigate occupational symptoms. Oncologic surgeons completed a survey of demographic information and occupational symptoms and injuries. Multivariate logistic regression was used to identify factors associated with occupational symptoms and injuries. A randomized cross-over pilot study of intraoperative foot mat use was conducted. One hundred twenty-seven surgeons completed surveys (response rate: 58%). The most commonly reported symptoms were fatigue, discomfort, stiffness, and back pain. An occupational injury was reported by 27.6% of surgeons. Of those injured, 65.7% received treatment, with 17.4% of those treated requiring surgery for their injury. In multivariate analysis, factors significantly associated with occupational injury were male sex (odds ratio [OR] 3.00, 95% CI 1.08 to 8.38), mean case length of 4 hours or more (OR 2.72, 95% CI 1.08 to 6.87), using a step to operate (OR 3.06, 95% CI 1.02 to 9.15), and neck pain (OR 4.81, 95% CI 1.64 to 14.12). In the foot mat pilot study (n= 20), mat use was associated with discomfort (OR 7.57, 95% CI 1.19 to 48.00), but no significant differences in leg volume change due to mat use were found. Most oncologic surgeons experience musculoskeletal symptoms from operating. Of the 28% of surgeons with an occupational injury, most required treatment. Intraoperative foot mat use was associated with increased discomfort.

Repeatability of Volume and Regional Body Composition Measurements of the Lower Limb Using Dual-energy X-ray Absorptiometry

Lower limb lymphedema is a dynamic condition in which tissue composition and volume measurements are affected. Various definitions of lower limb lymphedema exist but volume differences between the limbs are widely used. It is therefore necessary to have a readily available noninvasive measurement technique allowing multiple measurements of the lower limbs. This study investigated the repeatability of duplicate volume and regional body composition measurements of the lower limb using the GE Lunar Prodigy dual-energy X-ray absorptiometry (DXA) scanner Prodigy (GE Medical Systems, Madison, WI). Twenty-seven participants (54 limbs), 14 women and 13 men aged 33–71 years with body mass index ranging from 14 to 32 kg/m2 were recruited. Duplicate whole-body DXA scans were performed with repositioning between examinations. Regions of interest were manually drawn for the thigh, lower leg, and foot, and total volume was calculated using the density of bone mineral content, fat, and lean mass. The repeatability of the volume of the lower limb and regional thigh and lower leg tissue composition (bone mineral content, fat, and lean mass) was good with intraclass correlation coefficient values of 0.97 to 0.99, and narrow limits of agreement on the Bland–Altman plots. These results confirm DXA to be a highly repeatable method for volume and tissue composition measurements of the lower limb. In a population at risk of lymphedema, DXA offers a clinically readily available noninvasive method allowing multiple measurements of volume and tissue composition on a routine basis, important for diagnosing, monitoring, managing, and researching lymphedema.

Predicting race time in male amateur marathon runners.

The aim of the study was to analyze the relationship between anthropometry, training characteristics, muscular strength and effort-related cardiovascular response and marathon race time in male amateur runners. A total of 84 male amateur marathon runners aged between 23 and 70 years took part in this study (41.0±9.5 years). All of them competed in the 2013 edition of the Madrid Marathon with a finish time between 169.8 and 316 minutes (226.0±28.5 minutes). Age, running experience, number of marathon races finished, mean kilometers run weekly in the last three months, and previous personal best time in the 10 km, half marathon and marathon were recorded. Moreover, anthropometric characteristics, and the results from the Ruffier Test and a whole-body isometric force test were measured. After the marathon, the race time was registered. Training volume (r=-0.479; P=0.001), previous running milestones (marathon r=0.756; half-marathon r=0.812; 10-km r=0.732; P<0.001), cardiovascular fitness (r=0.371; P=0.001) and anthropometric variables (body mass, Body Mass Index, body fat percentage, skinfolds and lower leg volume) were correlated to marathon performance (P<0.05). Two regression models appeared from the data with r2>0.50. The best, including body fat percentage, heart rate change during the recovery after the Ruffier Test and the half-marathon race time, was strongly correlated with real marathon performance (r=0.77; P<0.001). A second regression model was proposed replacing the half-marathon performance with the 10-km race time, reducing the correlation to 0.73 (P<0.001). Marathon performance could be partially predicted by two different equations, including body fat percentage, recovery heart rate in the Ruffier Test and a half-marathon or 10-km performance.

LEG volume 22 issue 2 Cover and Back matter

LEG volume 22 issue 2 Cover and Back matter

LEG volume 22 issue 2 Cover and Front matter

LEG volume 22 issue 2 Cover and Front matter

Venous leg symptoms in healthy subjects assessed during prolonged standing.

The core symptoms of venous disease include leg discomfort or pain accompanied by sensations of heavy, weighty, or swollen legs. This suggests the presence of a cause and effect relationship between swelling and pain, resulting inthe assumption that a venous disorder is responsible. The aim of this study was to investigate the relationship between leg volume increase and symptoms provoked by a period of stationary standing and also to investigate the effect of medical compression stockings (MCS). Healthy volunteers were subject to stationary standing. Lower leg volume and the intensity and nature of the emerging symptoms were assessed seven times during 10minutes. Of 46 subjects analyzed after an initial test with bare legs, 18 (39%) developed no or few symptoms (≤2 on a Numeric Rating Scale [NRS] of 0 to 10). However, their leg volume increased as much as in the 28 subjects who experienced more symptoms. Oligosymptomatic subjects scored lower in a baseline questionnaire on leg symptoms of somatic and psychic origin than did volunteers with more symptoms. The oligosymptomatic subjects were excluded from the tests with MCS. In the 24 subjects who completed the whole study, the lower leg volume increased in two phases, reaching an increment of 44mL (standard deviation [SD], 18) or 1.73% (SD, 0.65) after 10minutes. Symptoms emerged and increased in a linear fashion, reaching a mean score of 2.93 NRS points (SD, 1.52) at 10minutes. The most prominent symptom was tingling (NRS, 5.07; SD, 3.05), followed by feelings of pressure and tension (NRS, 2.17; SD, 1.87). No correlation was found between volume increase and symptoms. MCS exerting an ankle pressure of 10 to 15mm Hg reduced the volume increase to 32mL (SD, 20), and MCS exerting 23 to 32mm Hg reduced it to 24mL (SD, 20; bothP< .001; difference between stockings, P= .06). Symptom intensity was reduced to NRS 2.06 (SD, 1.52) and 2.21 (SD,1.23; both P< .001), respectively. Both MCS reduced the symptoms equally (P= .38). Symptom reduction was not correlated with the prevention of volume increase. On prolonged stationary standing, leg volume increase and symptoms occur independently. MCS reduce volume increase according to the pressure they exert. Symptoms are reduced independent of the pressure exerted and the volume increase prevented. This suggests that MCS act in more ways than by a simple reduction in volume.

Effects of training in minimalist shoes on the intrinsic and extrinsic foot muscle volume

BackgroundMinimalist shoes have gained popularity recently because it is speculated to strengthen the foot muscles and foot arches, which may help to resist injuries. However, previous studies provided limited evidence supporting the link between changes in muscle size and footwear transition. Therefore, this study sought to examine the effects of minimalist shoes on the intrinsic and extrinsic foot muscle volume in habitual shod runners. The relationship between participants' compliance with the minimalist shoes and changes in muscle õvolume was also evaluated. MethodsTwenty habitual shod runners underwent a 6-month self-monitoring training program designed for minimalist shoe transition. Another 18 characteristics-matched shod runners were also introduced with the same program but they maintained running practice with standard shoes. Runners were monitored using an online surveillance platform during the program. We measured overall intrinsic and extrinsic foot muscle volume before and after the program using MRI scans. FindingsRunners in the experimental group exhibited significantly larger leg (P=0.01, Cohen's d=0.62) and foot (P<0.01, Cohen's d=0.54) muscle after transition. Foot muscle growth was mainly contributed by the forefoot (P<0.01, Cohen's d=0.64) but not the rearfoot muscle (P=0.10, Cohen's d=0.30). Leg and foot muscle volume of runners in the control group remained similar after the program (P=0.33–0.95). A significant positive correlation was found between participants' compliance with the minimalist shoes and changes in leg muscle volume (r=0.51; P=0.02). InterpretationHabitual shod runners who transitioned to minimalist shoes demonstrated significant increase in leg and foot muscle volume. Additionally, the increase in leg muscle volume was significantly correlated associated with the compliance of minimalist shoe use.