Plantar pressure reduction in the heel region through self-adjusting insoles with a heel cup in standard and individualized rocker shoes.

BACKGROUND: Effectiveness of therapeutic footwear in reducing peak pressure in persons with diabetes and loss of protective sensation to prevent diabetic foot ulcers varies due to manual production and possible changing foot structure. A previous two-way approach to address this issue, featuring individualized 3D-printed rocker midsoles and self-adjusting insoles, proved effective in the forefoot but less in the heel. To address this, new insoles incorporating a heel cup are developed. METHODS: In-shoe pressure was measured, while persons with diabetes and loss of protective sensation with high peak pressure (≥ 200 kPa) in the heel walked on a treadmill with control and individualized rocker shoe paired with control and new insole. FINDINGS: Generalized estimating equations revealed significant decrease in peak pressure in the proximal heel with the new insole alone and combined with rocker shoe compared to rocker shoe alone. For the distal heel, significant decrease in peak pressure is shown with the combination of new insole and rocker shoe compared to control shoe. For the forefoot and toes (excluding hallux) significant decrease in peak pressure is shown using the rocker shoe alone or combined with the heel cup compared to control shoe. INTERPRETATION: The new insole paired with rocker shoe is effective in reducing peak pressure in the distal heel. To have similar (or more) success in proximal heel, one could replace the rocker midsole with more compliant materials. The rocker shoe used separately or combined with a heel cup effectively reduces the peak pressure in the forefoot and other toes.

Toward a disruptive, minimally invasive small finger joint implant concept: Cellular and molecular interactions with materials in vivo.

Osteoarthritis (OA) poses significant therapeutic challenges, particularly OA that affects the hand. Currently available treatment strategies are often limited in terms of their efficacy in managing pain, regulating invasiveness, and restoring joint function. The APRICOT® implant system developed by Aurora Medical Ltd (Chichester, UK) introduces a minimally invasive, bone-conserving approach for treating hand OA (https://apricot-project.eu/). By utilizing polycarbonate urethane (PCU), this implant incorporates a caterpillar track-inspired design to promote the restoration of natural movement to the joint. Surface modifications of PCU have been proposed for the biological fixation of the implant. This study investigated the biocompatibility of PCU alone or in combination with two surface modifications, namely dopamine-carboxymethylcellulose (dCMC) and calcium-phosphate (CaP) coatings. In a rat soft tissue model, native and CaP-coated PCU foils did not increase cellular migration or cytotoxicity at the implant-soft tissue interface after 3 d, showing gene expression of proinflammatory cytokines similar to that in non-implanted sham sites. However, dCMC induced an amplified initial inflammatory response that was characterized by increased chemotaxis and cytotoxicity, as well as pronounced gene activation of proinflammatory macrophages and neoangiogenesis. By 21 d, inflammation subsided in all the groups, allowing for implant encapsulation. In a rat bone model, 6 d and 28 d after release of the periosteum, all implant types were adapted to the bone surface with a surrounding fibrous capsule and no protracted inflammatory response was observed. These findings demonstrated the biocompatibility of native and CaP-coated PCU foils as components of APRICOT® implants. STATEMENT OF SIGNIFICANCE: Hand osteoarthritis treatments require materials that minimize irritation of the delicate finger joints. Differing from existing treatments, the APRICOT® implant leverages polycarbonate urethane (PCU) for minimally invasive joint replacement. This interdisciplinary, preclinical study investigated the biocompatibility of thin polycarbonate urethane (PCU) foils and their surface modifications with calcium-phosphate (CaP) or dopamine-carboxymethylcellulose (dCMC). Cellular and morphological analyses revealed that both native and Ca-P coated PCU elicit transient inflammation, similar to sham sites, and a thin fibrous encapsulation in soft tissues and on bone surfaces. However, dCMC surface modification amplified initial chemotaxis and cytotoxicity, with pronounced activation of proinflammatory and neoangiogenesis genes. Therefore, native and CaP-coated PCU possess sought-for biocompatible properties, crucial for patient safety and performance of APRICOT® implant.

A combined musculoskeletal and finite element model of a foot to predict plantar pressure distribution.

In this study, a combined subject-specific numerical and experimental investigation was conducted to explore the plantar pressure of an individual. The research utilized finite element (FE) and musculoskeletal modelling based on computed tomography (CT) images of an ankle-foot complex and three-dimensional gait measurements. Muscle forces were estimated using an individualized multi-body musculoskeletal model in five gait phases. The results of the FE model and gait measurements for the same subject revealed the highest stress concentration of 0.48 MPa in the forefoot, which aligns with previously-reported clinical observations. Additionally, the study found that the encapsulated soft tissue FE model with hyper-elastic properties exhibited higher stresses compared to the model with linear-elastic properties, with maximum ratios of 1.16 and 1.88 MPa in the contact pressure and von-Mises stress, respectively. Furthermore, the numerical simulation demonstrated that the use of an individualized insole caused a reduction of 8.3% in the maximum contact plantar pressure and 14.7% in the maximum von-Mises stress in the encapsulated soft tissue. Overall, the developed model in this investigation holds potential for facilitating further studies on foot pathologies and the improvement of rehabilitation techniques in clinical settings.

Effects of heel apex position, apex angle and rocker radius on plantar pressure in the heel region.

Introduction: Rocker shoes and insoles are used to prevent diabetic foot ulcers in persons with diabetes mellitus and loss of protective sensation, by reducing the plantar pressure in regions with high pressure values (>200 kPa) (e.g., hallux, metatarsal heads and heel). However, forefoot rocker shoes that reduce pressure in the forefoot inadvertently increase pressure in the heel. No studies focused on mitigating the negative effects on heel pressure by optimizing the heel rocker midsole, yet. Therefore, we analyze the effect of different heel rocker parameters on the heel plantar pressure. Methods: In-shoe pressure was measured, while 10 healthy participants walked with control shoe and 10 different heel rocker settings. Peak pressure was determined in 7 heel masks, for all shoes. Generalized estimating equations was performed to test the effect of the different shoes on the peak pressure in the different heel masks. Results: In the proximal heel, a rocker shoe with distal apex position, small rocker radius and large apex angle (100°), shows the largest significant decrease in peak pressure compared to rocker shoes with more proximally located apex positions. In the midheel and distal heel, the same rocker shoes or any other rocker shoes, analyzed in this study, do not reduce the PP more than 2 % compared to the control shoe. For the midheel and distal heel region with high pressure values (>200 kPa), rocker shoes alone are not the correct option to reduce the pressure to below 200 kPa. Conclusion: When using rocker shoes to reduce the pressure in the forefoot, a heel rocker midsole with a distal apex position, small rocker radius and apex angle of 100°, mitigates the negative effects on proximal heel pressure. For the midheel and distal heel, other footwear options as an addition or instead of rocker shoes are needed to reduce the pressure.

Factors influencing the use of therapeutic footwear in persons with diabetes mellitus and loss of protective sensation: A focus group study.

BACKGROUND: Persons with diabetes mellitus (DM) and loss of protective sensation (LOPS) due to peripheral neuropathy do not use their therapeutic footwear (TF) consistently. TF is essential to prevent foot ulceration. In order to improve compliance in using TF, influencing factors need to be identified and analyzed. Persons with a history of foot ulceration may find different factors important compared with persons without ulceration or persons who have never used TF. Therefore, the objective of this study was to determine factors perceived as important for the use of TF by different groups of persons with DM and LOPS. METHOD: A qualitative study was performed using focus group discussions. Subjects (n = 24) were divided into 3 focus groups based on disease severity: ulcer history (HoU) versus no ulcer history (no-HoU) and experience with TF (TF) versus no experience (no-TF). For each group of 8 subjects (TF&HoU; TF&no-HoU; no-TF&no-HoU), an online focus group discussion was organized to identify the most important influencing factors. Transcribed data were coded with Atlas.ti. The analysis was performed following the framework approach. RESULTS: The factors comfort and fit and stability/balance were ranked in the top 3 of all groups. Usability was ranked in the top 3 of group-TF&noHoU and group-noTF&noHoU. Two other factors, reducing pain and preventing ulceration were ranked in the top 3 of group-TF&noHoU and group-TF&HoU, respectively. CONCLUSION: Experience with TF and a HoU influence which factors are perceived as important for TF use. Knowledge of these factors during the development and prescription process of TF may lead to increased compliance. Although the main medical reason for TF prescription is ulcer prevention, only 1 group gave this factor a high ranking. Therefore, next to focusing on influencing factors, person-centered education on the importance of using TF to prevent ulcers is also required.

Three-dimensional correction of scoliosis by a double spring reduction system as a dynamic internal brace: a pre-clinical study in Göttingen minipigs.

BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) is a major skeletal deformity that is characterized by a combination of apical rotation, lateral bending and apical lordosis. To provide full 3D correction, all these deformations should be addressed. We developed the Double Spring Reduction (DSR) system, a (growth-friendly) concept that continuously corrects the deformity through two different elements: A posterior convex Torsional Spring Implant (TSI) that provides a derotational torque at the apex, and a concave Spring Distraction System (SDS), which provides posterior, concave distraction to restore thoracic kyphosis. PURPOSE: To determine whether the DSR components are able to correct an induced idiopathic-like scoliosis and to compare correction realized by the TSI alone to correction enforced by the complete DSR implant. STUDY DESIGN/SETTING: Preclinical randomized animal cohort study. PATIENT SAMPLE: Twelve growing Göttingen minipigs. OUTCOME MEASURES: Coronal Cobb angle, T10-L3 lordosis/kyphosis, apical axial rotation, relative anterior lengthening. METHODS: All mini-pigs received the TSI with a contralateral tether to induce an idiopathic-like scoliosis with apical rotation (mean Cobb: 20.4°; mean axial apical rotation: 13.1°, mean lordosis: 4.9°). After induction, the animals were divided into two groups: One group (N=6) was corrected by TSI only (TSI only-group), another group (N=6) was corrected by a combination of TSI and SDS (DSR-group). 3D spinal morphology on CT was compared between groups over time. After 2 months of correction, animals were euthanized. RESULTS: Both intervention groups showed excellent apical derotation (TSI only-group: 15.0° to 5.4°; DSR-group: 11.2° to 3.5°). The TSI only-group showed coronal Cobb improvement from 22.5° to 6.0°, while the DSR-group overcorrected the 18.3° Cobb to -9.2°. Lordosis was converted to kyphosis in both groups (TSI only-group: -4.6° to 4.3°; DSR-group: -5.2° to 25.0°) which was significantly larger in the DSR-group (p<.001). CONCLUSIONS: The TSI alone realized strong apical derotation and moderate correction in the coronal and sagittal plane. The addition of distraction on the posterior concavity resulted in more coronal correction and reversal of induced lordosis into physiological kyphosis. CLINICAL SIGNIFICANCE: This study shows that dynamic spring forces could be a viable method to guide the spine towards healthy alignment, without fusing it or inhibiting its growth.

Overview and Strategy Analysis of Technology-Based Nonpharmacological Interventions for In-Hospital Delirium Prevention and Reduction: Systematic Scoping Review.

BACKGROUND: Delirium prevention is crucial, especially in critically ill patients. Nonpharmacological multicomponent interventions for preventing delirium are increasingly recommended and technology-based interventions have been developed to support them. Despite the increasing number and diversity in technology-based interventions, there has been no systematic effort to create an overview of these interventions for in-hospital delirium prevention and reduction. OBJECTIVE: This systematic scoping review was carried out to answer the following questions: (1) what are the technologies currently used in nonpharmacological technology-based interventions for preventing and reducing delirium? and (2) what are the strategies underlying these currently used technologies? METHODS: A systematic search was conducted in Scopus and Embase between 2015 and 2020. A selection was made in line with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Studies were eligible if they contained any type of technology-based interventions and assessed delirium-/risk factor-related outcome measures in a hospital setting. Data extraction and quality assessment were performed using a predesigned data form. RESULTS: A total of 31 studies were included and analyzed focusing on the types of technology and the strategies used in the interventions. Our review revealed 8 different technology types and 14 strategies that were categorized into the following 7 pathways: (1) restore circadian rhythm, (2) activate the body, (3) activate the mind, (4) induce relaxation, (5) provide a sense of security, (6) provide a sense of control, and (7) provide a sense of being connected. For all technology types, significant positive effects were found on either or both direct and indirect delirium outcomes. Several similarities were found across effective interventions: using a multicomponent approach or including components comforting the psychological needs of patients (eg, familiarity, distraction, soothing elements). CONCLUSIONS: Technology-based interventions have a high potential when multidimensional needs of patients (eg, physical, cognitive, emotional) are incorporated. The 7 pathways pinpoint starting points for building more effective technology-based interventions. Opportunities were discussed for transforming the intensive care unit into a healing environment as a powerful tool to prevent delirium. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD42020175874; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=175874.

Induction of a representative idiopathic-like scoliosis in a porcine model using a multidirectional dynamic spring-based system.

BACKGROUND CONTEXT: Scoliosis is a 3D deformity of the spine in which vertebral rotation plays an important role. However, no treatment strategy currently exists that primarily applies a continuous rotational moment over a long period of time to the spine, while preserving its mobility. We developed a dynamic, torsional device that can be inserted with standard posterior instrumentation. The feasibility of this implant to rotate the spine and preserve motion was tested in growing mini-pigs. PURPOSE: To test the quality and feasibility of the torsional device to induce the typical axial rotation of scoliosis while maintaining growth and mobility of the spine. STUDY DESIGN: Preclinical animal study with 14 male, 7 month old Gottingen mini-pigs. Comparison of two scoliosis induction methods, with and without the torsional device, with respect to 3D deformity and maintenance of the scoliosis after removal of the implants. METHODS: Fourteen mini-pigs received either a unilateral tether-only (n=6) or a tether combined with a contralateral torsional device (n=8). X-rays and CT-scans were made post-operative, at 8 weeks and at 12 weeks. Flexibility of the spine was assessed at 12 weeks. In 3 mini-pigs per condition, the implants were removed and the animals were followed until no further correction was expected. RESULTS: At 12 weeks the tether-only group yielded a coronal Cobb angle of 16.8±3.3°For the tether combined with the torsional device this was 22.0±4.0°. The most prominent difference at 12 weeks was the axial rotation with 3.6±2.8° for the tether-only group compared to 18.1±4.6° for the tether-torsion group. Spinal growth and flexibility remained normal and comparable for both groups. After removal of the devices, the induced scoliosis reduced by 41% in both groups. There were no adverse tissue reactions, implant complications or infections. CONCLUSION: The present study indicates the ability of the torsional device combined with a tether to induce a flexible idiopathic-like scoliosis in mini-pigs. The torsional device was necessary to induce the typical axial rotation found in human scoliosis. CLINICAL SIGNIFICANCE: The investigated torsional device could induce apical rotation in a flexible and growing spine. Whether this may be used to reduce a scoliotic deformity remains to be investigated.

Improving Hands-free Speech Rehabilitation in Patients With a Laryngectomy: Proof-of-Concept of an Intratracheal Fixation Device.

Permanent hands-free speech with the use of an automatic speaking valve (ASV) is regarded as the optimal voice rehabilitation after total laryngectomy. Due to fixation problems, regular ASV use in patients with a laryngectomy is limited. We have developed an intratracheal fixation device (ITFD) composed of an intratracheal button augmented by hydrophilic foam around its shaft. This study evaluates the short-term effectiveness and experienced comfort of this ITFD during hands-free speech in 7 participants with a laryngectomy. We found that 4 of 7 participants had secure ASV fixation inside the tracheostoma during hands-free speech for at least 30 minutes with the ITFD. The ITFD's comfort was perceived positively overall. The insertion was perceived as being mildly uncomfortable but not painful. This proof-of-concept study demonstrates the feasibility of the ITFD that might improve stomal attachment of ASVs, and it provides the basis for further development toward a prototype suitable for long-term daily use.

The potential of spring distraction to dynamically correct complex spinal deformities in the growing child.

PURPOSE: Current treatment of progressive early onset scoliosis involves growth-friendly instrumentation if conservative treatment fails. These implants guide growth by passive sliding or repeated lengthenings. None of these techniques provide dynamic correction after implantation. We developed the spring distraction system (SDS), by using one or multiple compressed springs positioned around a standard sliding rod, to provide active continuous distraction of the spine to stimulate growth and further correction. The purpose of this study was to determine feasibility and proof of concept of the SDS. METHODS: We developed a versatile, dynamic spring distraction system for patients who would benefit from active continuous distraction. This prospective case series evaluates four patients with exceptional and progressive congenital spine deformities. RESULTS: Four patients had a mean age of 6.8 years at surgery with a mean follow-up of 36 months (range 25-45). The mean progressive thoracic lordosis, which was the reason for initiating surgical treatment in two patients, changed from 32° lordosis preoperatively to 1° kyphosis post-operatively. During follow-up, this further improved to 32° thoracic kyphosis. In the two other patients, with cervicothorcacic scoliosis, the main coronal curve improved from 79° pre-operatively to 56° post-operatively and further improved to 42°. The mean T1-S1 spine growth during follow-up for all patients was 1.3 cm/year. There was one reoperation because of skin problems and no device-failures. CONCLUSION: These early results show the feasibility and the proof of concept of spring-based distraction as a dynamic growth-enhancing system with the potential of further correction of the deformity after implantation.

Comparison of the mechanical properties of biodegradable and titanium osteosynthesis systems used in oral and maxillofacial surgery.

To guide the selection of osteosynthesis systems, this study compared the mechanical properties of biodegradable and titanium osteosynthesis systems. SonicPins Rx and xG were subjected to pull-out tests. Additionally, 15 biodegradable (Inion CPS 2.0 and 2.5 mm; LactoSorb 2.0 mm; Macropore 2.0 mm; Polymax 2.0 mm; BioSorb FX 2.0 mm; ResorbX 2.1 mm; Osteotrans-MX 2.0 mm with plate thicknesses 1.0 and 1.4 mm; SonicWeld Rxplate/Rxpins, xGplate/Rxpins and xGplate/xGpins 2.1 mm without and with tapping the burr hole) and six titanium (CrossDrive (2006), CrossDrive (2018), MaxDrive; all 1.5 and 2.0 mm) straight, four-hole osteosynthesis systems were evaluated. All systems were subjected to tensile, bending and torsion tests. Pull-out loads of the SonicPins were comparable (P = 0.423). Titanium systems' tensile loads were higher than biodegradable systems (P < 0.001). CrossDrive (2018) and MaxDrive systems' tensile and torsional stiffness were lower, accompanied with higher ductility, than corresponding CrossDrive (2006) systems (P < 0.001). Bending stiffness of 1.5 mm titanium systems was comparable to, and of the 2.0 mm systems higher than, all biodegradable systems (P < 0.001). Regarding biodegradable systems, Inion CPS 2.5 mm had highest tensile load and torsional stiffness, SonicWeld 2.1 mm highest tensile stiffness, and BioSorbFX 2.0 mm highest bending stiffness (P < 0.001). On the basis of the results of this study, the CrossDrive (2018) and MaxDrive 1.5 mm titanium systems are recommended for midface fractures (e.g., zygomatic or maxillary fractures) and osteotomies (e.g., Le Fort I osteotomy), and the CrossDrive (2018) and MaxDrive 2.0 mm titanium systems for mandibular fractures and osteotomies when a titanium osteosynthesis system is used. When there is an indication for a biodegradable osteosynthesis system, the SonicWeld 2.1 mm or BioSorbFX 2.0 mm are recommended for midface fractures and osteotomies, and the Inion CPS 2.5 mm biodegradable system for mandibular osteotomies and non-load bearing mandibular fractures, especially when high torsional forces are expected (e.g., mandibular symphysis fractures).

Pulmonary versus aortic pressure behavior of a bovine pericardial valve.

BACKGROUND: The Carpentier Edwards Perimount Magna Ease aortic valvular prosthesis (Edwards Lifesciences, Irvine, Calif) has been among the most frequently and successfully used tissue prosthetic cardiac valves. Furthermore, this prosthesis has been used off-label in the pulmonary position. Until now, there has been a paucity of data regarding the functioning of tissue prosthetic valves under pulmonary conditions. METHODS: Using a pulse duplicator, hydrodynamic characteristics of a 21-mm and 25-mm Magna Ease valve were evaluated. Among parameters evaluated were leakage orifice area, closing time (ie, time required to close), and leakage duration. This procedure was performed under different pulmonic pressure conditions (15/5 mm Hg, 28/11 mm Hg, 73/32 mm Hg) and normal aortic pressure (120/80 mm Hg) as a reference. Moving images were obtained using a Phantom MIRO M320S high-speed camera (Vision Research Inc, Wayne, NJ) at 600 frames per second and used to analyze valve area in closed position. RESULTS: Under normal pulmonic conditions (28/11 mm Hg) the leakage orifice area was 0.020 ± 0.012 mm2 for the 21-mm valve and 0.054 ± 0.041 mm2 for the 25-mm valve (P = .03). Hydrodynamic characteristics of the valves differed between pulmonary and aortic testing condition. Valve closing volumes were significantly lower under pulmonary hypotension and normal pulmonary conditions than under normal aortic conditions (P < .05). CONCLUSIONS: Under normal pulmonary pressure conditions, the hydrodynamic characteristics of Magna Ease valves are significantly different compared with aortic conditions. Further research is needed to determine whether these results are associated with prosthetic valve failure.

Evaluation of intuitive trunk and non-intuitive leg sEMG control interfaces as command input for a 2-D Fitts's law style task.

Duchenne muscular dystrophy (DMD) is a muscular condition that leads to muscle loss. Orthotic devices may present a solution for people with DMD to perform activities of daily living (ADL). One such device is the active trunk support but it needs a control interface to identify the user's intention. Myoelectric control interfaces can be used to detect the user's intention and consequently control an active trunk support. Current research on the control of orthotic devices that use surface electromyography (sEMG) signals as control inputs, focuses mainly on muscles that are directly linked to the movement being performed (intuitive control). However in some cases, it is hard to detect a proper sEMG signal (e.g., when there is significant amount of fat), which can result in poor control performance. A way to overcome this problem might be the introduction of other, non-intuitive forms of control. This paper presents an explorative study on the comparison and learning behavior of two different control interfaces, one using sEMG of trunk muscles (intuitive) and one using sEMG of leg muscles that can be potentially used for an active trunk support (non-intuitive). Six healthy subjects undertook a 2-D Fitts's law style task. They were asked to steer a cursor into targets that were radially distributed symmetrically in five directions. The results show that the subjects were generally able to learn to control the tasks using either of the control interfaces and improve their performance over time. Comparison of both control interfaces demonstrated that the subjects were able to learn the leg control interface task faster than the trunk control interface task. Moreover, the performance on the diagonal-targets was significantly lower compared to the one directional-targets for both control interfaces. Overall, the results show that the subjects were able to control a non-intuitive control interface with high performance. Moreover, the results indicate that the non-intuitive control may be a viable solution for controlling an active trunk support.

Influence of Transvalvar Pressure Gradient on Hinge Washing in Closed Mechanical Prosthetic Cardiac Valves Under Pulmonary Pressure Conditions: A Comparative In Vitro Study.

OBJECTIVE: Hinge washing is a crucial factor in the prevention of mechanical prosthetic valvar thrombosis, especially in the pulmonary valve position. The aim of this laboratory study was to determine the relationship between pressure difference and the amount of hinge washing in the closed position, using the pressures that are normal for the right ventricle and pulmonary artery. METHODS: In an in vitro setting, four different bileaflet mechanical valves were tested for hinge washing in closed position. Based on similarity in inner diameter (range: 20.5-21.4 mm), the following valves were tested: Abbott SJM Regent size 23, Cryolife On-X size 23, LivaNova Carbomedics-R size 25, Medtronic Open Pivot (M-OP)-A size 25. Tests were carried out in a range between 3 and 100 mm Hg pressure difference, using water as a test fluid. The amount of leakage per minute through the closed valve was measured. RESULTS: All four valves showed an increase in leakage with increasing transvalvar gradient, and the relationship between pressure and leakage behaves in logarithmic fashion. Leakage under normal pulmonary diastolic pressure conditions (10 mm Hg) was between 23.3% and 29.3% of the leakage under aortic diastolic pressure conditions (80 mm Hg). The Cryolife On-X valve showed the highest closed leakage volume under pulmonary conditions (10 mm Hg) 0.254 ± 0.01 (L/min), where the Medtronic M-OP showed the lowest leakage volume with 0.125 ± 0.014 (mL/min). CONCLUSION: Hinge washing is related to transvalvar pressure difference in closed position. Valve brands differed significantly from each other in the amount of hinge washing.

Exploring physiological signals on people with Duchenne muscular dystrophy for an active trunk support: a case study.

BACKGROUND: Arm support devices are available to support people with Duchenne muscular dystrophy (DMD), but active trunk support devices are lacking. An active trunk support device can potentially extend the reach of the arm and stabilize the unstable trunk of people with DMD. In a previous study, we showed that healthy people were able to control an active trunk support using four different control interfaces (based on joystick, force on feet, force on sternum and surface electromyography). All four control interfaces had different advantages and disadvantages. The aim of this study was to explore which of the four inputs is detectably used by people with DMD to control an active trunk support. RESULTS: The results were subject-dependent in both experiments. In the active experiment, the joystick was the most promising control interface. Regarding the static experiment, surface electromyography and force on feet worked for two out of the three subjects. CONCLUSIONS: To our knowledge, this is the first time that people with DMD have engaged in a control task using signals other than those related to their arm muscles. According to our findings, the control interfaces have to be customised to every DMD subject.

Evaluation of Control Interfaces for Active Trunk Support.

A feasibility study was performed to evaluate the control interfaces for a novel trunk support assistive device (Trunk Drive), namely, joystick, force on sternum, force on feet, and electromyography (EMG) to be used by adult men with Duchene muscular dystrophy. The objective of this paper was to evaluate the performance of the different control interfaces during a discrete position tracking task. We built a one degree of freedom flexion-extension active trunk support device that was tested on 10 healthy men. An experiment, based on the Fitts law, was conducted, whereby subjects were asked to steer a cursor representing the angle of the Trunk Drive into a target that was shown on a graphical user interface, using the above-mentioned control interfaces. The users could operate the Trunk Drive via each of the control interfaces. In general, the joystick and force on sternum were the fastest in movement time (more than 40%) without any significant difference between them, but there was a significant difference between force on sternum on the one hand, and EMG and force on feet on the other. All control interfaces proved to be feasible solutions for controlling an active trunk support, each of which had specific advantages.

Ten cold clubfeet.

Background and purpose - Idiopathic clubfeet are commonly treated with serial manipulation and casting, known as the Ponseti method. The use of Plaster of Paris as casting material causes both exothermic and endothermic reactions. The resulting temperature changes can create discomfort for patients. Patients and methods - In 10 patients, we used a digital thermometer with a data logger to measure below-cast temperatures to create a thermal profile of the treatment process. Results - After the anticipated temperature peak, a surprisingly large dip was observed (Tmin = 26 °C) that lasted 12 hours. Interpretation - Evaporation of excess water from a cast might be a cause for discomfort for clubfoot patients and subsequently, their caregivers.

Development and evaluation of a passive trunk support system for Duchenne muscular dystrophy patients.

BACKGROUND: Patients with Duchenne muscular dystrophy gradually lose the ability to use different muscles of their body. Consequently, they lose the ability to stabilize their trunk against gravity. This hinders them to effectively perform different daily activities. In this paper, we describe the design, realization and evaluation of a trunk orthosis for these patients that should allow them to move their trunk and maintain stability. METHOD: This study aimed to primarily assess the effectiveness of the trunk support system in terms of unloading of trunk muscles, so only healthy participants were recruited for this phase of the study. Measurements were done on 10 healthy participants (23.4±2.07 [M±SD] years old, average body weight 68.42±24.22 [M±SD] kg). The experiment comprised maintaining a constant trunk posture in three different device conditions (control without orthosis and two conditions with different configurations of the orthosis), at four different flexion angles (10°, 20°, 30°, 40°) for each device condition and for two load conditions (with and without stretching the arms). Electromyography (EMG) signals from the trunk muscles were measured to estimate activation levels of the trunk muscles (iliocostalis, longissimus, external oblique and rectus abdominis) and a motion capture system was used to record the movement of the participants during the experiment. RESULTS: Wearing the orthosis caused reductions in longissimus and iliocostalis activity. The average muscle activity level was 5%-10% of maximum voluntary contraction in the unsupported conditions for those particular muscles. This level was reduced to 3%-9% of maximal voluntary contraction for the supported conditions. No effect on external oblique and rectus abdominis activity was observed. Moreover, no pain or discomfort was reported by any of the participants during the experiment. The results from the current experiment also suggests the necessity of lumber stabilizing systems while using trunk orthosis. CONCLUSION: The developed orthosis reduces trunk muscle activation level and provides a solid step for further development of support systems for Duchenne muscular dystrophy patients. TRIAL REGISTRATION: The current study was approved by the medical ethics committee Arnhem-Nijmegen (study number: NL53143.091.15 ), The Netherlands.

Coupled motions in human and porcine thoracic and lumbar spines.

Coupled motions, i.e., motions along axes other than the loaded axis, have been reported to occur in the human spine, and are likely to be influenced by inclined local axes due to the sagittal plane spine curvature. Furthermore, the role of facet joints in such motions is as yet unclear. Therefore, this study aimed at assessing coupled motions in multiple spine sections in vitro, before and after removal of posterior elements. Six elderly human and 6 young porcine spines were sectioned in four segments (high thoracic, mid thoracic, low thoracic and lumbar), each consisting of four vertebrae and three intervertebral discs. Segments were loaded along each of the three axes, and three-dimensional rotations of the middle segment were quantified. Subsequently, posterior elements were removed and the protocol was repeated. To avoid mixed loading between Axial Rotation (AR) and Lateral Bending (LB), in contrast to other studies, local axes at the vertebrae were defined as aligned with the loading device prior to each load application. Expressed as a percentage of motion in the loaded direction, coupled motions were on average larger in human (22.7%, SD = 2.2%) than in porcine (11.9%, SD = 1.2%) spines (p < .001). Largest coupled motions were obtained in AR loading of the lumbar spine segments, with mean magnitudes averaged over coupling axes for human L2-L3 joints of 48.9% (SD = 13.2%), including somewhat more LB (56.4%, SD = 18.6) than FE (41.4%, SD = 14.1%) coupling. For porcine L3-L4 joints average coupling in AR loading was 29.3% (SD = 8.2%). In human segments removal of posterior elements only had substantial effects in the lumbar spine segments, where posterior element removal decreased coupled motion during AR loading, averaged over LB and FE coupling, from 48.9% (SD = 13.2%) to 27.7% (SD = 6.1%), mainly through increased motion in the loaded direction. The present results indicate that coupled motions were largest in the lumbar spine. In human spines, posterior elements only contributed to coupled motions in lumbar axial rotation loading.

Effects of flexible and rigid rocker profiles on in-shoe pressure.

Rocker profiles are commonly used in the prevention of diabetic foot ulcers. Rockers are mostly stiffened to restrict toe plantarflexion to ensure proper offloading. It is also described that toe dorsiflexion should be restricted. However, the difference in effect on plantar pressure between rigid rockers that restrict this motion and flexible rockers that do not is unknown. In-shoe plantar pressure data were collected for a control shoe and the same shoe with rigid and flexible rockers with the apex positioned at 50% and 60%. For 29 healthy female adults peak plantar pressure (PP), maximum mean pressure (MMP) and force-time integral (FTI) were determined for seven regions of the foot. Generalized estimate equation was used to analyse the effect of the different shoes on the outcome measures for these regions. Compared to the control shoe a significant increase of PP and FTI was found at the first toe for both rigid rockers and the flexible rocker with the apex positioned at 60%, while MMP was significantly increased in rockers with an apex position of 60% (p<0.001). PP at the first toe was significantly lower in flexible rockers when compared to rigid rockers (p<0.001). For both central and lateral forefoot PP and MMP were significantly more reduced in rigid rockers (p<0.001), while for the medial forefoot no differences were found. The use of rigid rockers results in larger reductions of forefoot plantar pressures, but in worse increase of plantar pressures at the first toe compared to rockers that allow toe dorsiflexion.