Consumer design priorities for upper limb prosthetics

Purpose. To measure consumer satisfaction with upper limb prosthetics and provide an enumerated list of design priorities for future developments.

Methods. A self-administered, anonymous survey collected information on participant demographics, history of and goals for prosthesis use, satisfaction, and design priorities. The questionnaire was available online and in paper format and was distributed through healthcare providers, community support groups, and one prosthesis manufacturer; 242 participants of all ages and levels of upper limb absence completed the survey.

Results. Rates of rejection for myoelectric hands, passive hands, and body-powered hooks were 39%, 53%, and 50%, respectively. Prosthesis wearers were generally satisfied with their devices while prosthesis rejecters were dissatisfied. Reduced prosthesis weight emerged as the highest priority design concern of consumers. Lower cost ranked within the top five design priorities for adult wearers of all device types. Life-like appearance is a priority for passive/cosmetic prostheses, while improved harness comfort, wrist movement, grip control and strength are required for body-powered devices. Glove durability, lack of sensory feedback, and poor dexterity were also identified as design priorities for electric devices.

Conclusions. Design priorities reflect consumer goals for prosthesis use and vary depending on the type of prosthesis used and age. Future design efforts should focus on the development of more light-weight, comfortable prostheses.     

Progressive upper limb prosthetics

The field of upper extremity prosthetics is a constantly changing arena as researchers and prosthetists strive to bridge the gap between prosthetic reality and upper limb physiology. With the further development of implantable neurologic sensing devices and targeted muscle innervation (discussed elsewhere in this issue), the challenge of limited input to control vast outputs promises to become a historical footnote in the future annals of upper limb prosthetics. Soon multidextrous terminal devices, such as that found in the iLimb system(Touch EMAS, Inc., Edinburgh, UK), will be a clinical reality (Fig. 22). Successful prosthetic care depends on good communication and cooperation among the surgeon, the amputee, the rehabilitation team, and the scientists harnessing the power of technology to solve real-life challenges. If the progress to date is any indication, amputees of the future will find their dreams limited only by their imagination.     

Mechanical performance of inflatable inserts used in limb prosthetics

Inflatable insert products used to overcome residual limb shrinkage were evaluated in a bench test environment under compressive loading conditions. Pressure-loss tests under static loading demonstrated that after inserts were inflated to 43.4 to 45.6 kPa, insert pressures reduced from 0.09%/min to 1.36%/min in the first 5 min and from 0.00%/min to 0.27%/min in the subsequent 55 min. As inserts were inflated, they demonstrated at least two phases in their pressure versus thickness curves: A relatively low-slope portion (Phase I) was followed by a high-slope portion (Phase II). The transition from Phase I to Phase II occurred at more than a 12-mm thickness, a thickness greater than that considered acceptable for practical clinical use (10 mm). This result suggests that in a socket, stress to resist insert expansion is taken by the residual limb and socket more than by the insert itself. Cyclic-loading tests under constrained thickness conditions demonstrated that local stiffness was more sensitive to insert pressure than to constraint spacing (insert thickness). The static and dynamic test results help to explain why some users claim that inserts do not provide equal and consistent support unless inflated to a very high insert pressure. An insert that allowed adjustment of the location of the Phase I to Phase II transition point in the pressure versus thickness curve might help to overcome these limitations.     

髋受力下肢力量训练器对人体跑跳极限运动能力最大后蹬力提高的作用

背景:人类后蹬力量可能是一种未能有效开发并具有极大开发潜力的动力源,阐明后蹬力量与下肢力量的关系对人体运动科学理论的发展具有重要意义。目的:观察髋受力下肢力量训练器与最大后蹬力量、最大下肢力量提高的关系。设计:观察对比分析。单位:中国海洋大学体育系。对象:实验于2000-12/2001-11年在中国海洋大学完成,选择94名从未用过髋受力训练器的健康男大学生运动员,平均(19.7±1.7)岁,体质量(75.27±2.93)kg,所有被试对象均对受试项目知情同意。方法:随机抽取其中46名受试者为实验组,采用髋受力下肢力量训练器(远固定髋受力下肢力量训练器型号:HNLPT-04Ed;近固定髋受力下肢力量训练器型号:HFLPT-04E,研制单位为中国海洋大学)进行历时11个月的后蹬力量提高训练。其余48名作为对照组采用现有的力量训练方法,即抗阻前蹬和负重蹲起。实验组受试者进行力量练习和测试时,坐于顶髋坐椅上,身体正直。脚踩踏板,按预定角度和轨迹作蹬伸运动。采用近固定机时,练习者的躯干和髋部固定不动,腿蹬踏板向后运动。采用远固机时,踏板和脚不动,髋部和躯干靠腿的蹬伸向前运动。①采用多功能力量训练器和远固定髋受力下肢力量训练器分别测定94名从未用过髋受力训练器的受试者的最大下肢力量和最大后蹬力量。②对两组受试对象于训练前后最大下肢力量和最大后蹬力量进行测量比较。主要观察指标:①94名从未用过髋受力训练器的受试者最大下肢力量和最大后蹬力量。②实验组及对照组受试对象于训练前后最大下肢力量和最大后蹬力量进行测量比较。结果:纳入实验组46名及对照组48名受试对象均进入结果分析。①受试者平均后蹬力量为(1135.53±196.98)N,小于最大下肢力量[(2414.62±424.05)N,P<0.01]。②经过11个月的髋受力下肢力量训练法的专项力量训练,实验组受试对象训练前后的最大后蹬力量高于实验前[(1124.94±206.19),1762.24±193.45]N,P<0.01],对照组受试对象训练前后的最大后蹬力量差异无统计学意义。结论:通过髋受力下肢力量训练使后蹬力量获得的提高是现有任何训练方法和训练器所无法获得的人体极限运动能力的提高,可使跑、跳世界纪录大幅度突破成为可能。     

Physical activity participation amongst individuals with lower limb amputation

Purpose: To examine physical activity participation amongst individuals with lower limb amputation.

Method: Adults with lower limb amputation were convenience-sampled from a major metropolitan hospital outpatient amputee service and completed the International Physical Activity Questionnaire.

Results: Seventy-two individuals (65% male), mean age 53.6 (SD?=?16.8) years, who were 10.8 (SD?=?12.6) years post amputation (60% transtibial) participated in the study. Thirty-eight percent of participants (n?=?27) undertook “high” levels, 26% (n?=?19) undertook “moderate” levels, and 36% (n?=?26) undertook “low” levels of physical activity but cumulative activity levels were low. Participants most commonly undertook domestic-related activities (n?=?53, 74%) and moderate-intensity activities (n?=?54, 75%). Physical activity levels were found to be significantly lower amongst individuals who did not work, individuals with dysvascular amputation and individuals who lived with others. Physical activity levels showed a weak, significant, correlation to age (r_s (70)?=??0.259, p?=?0.028) and time post amputation (r_s (70)?=?0.237, p?=?0.049).

Conclusion: This study provides clinicians with information about physical activity participation amongst individuals with lower limb amputation. The majority of participants in this study (n?=?44, 61%) did not accumulate sufficient “total physical activity” to be classified as “sufficiently active” and 33% (n?=?24) of participants were classified as “sedentary”.

• Implications for Rehabilitation

• Regular physical activity participation is associated with many health benefits.

• This study found the majority of individuals with lower limb amputation (61%) did not undertake sufficient total physical activity to be classified as “sufficiently active”.

• Health professionals working in rehabilitation can play an important role in encouraging individuals to increase physical activity participation.

• The study’s findings may guide health professionals on where to direct their focus to promote increased physical activity participation amongst individuals with lower limb amputation.

     

Custom implant design for large cranial defects

Purpose

The aim of this work was to introduce a computer-aided design (CAD) tool that enables the design of large skull defect (>100 \(\mathrm{cm}^2\)) implants. Functional and aesthetically correct custom implants are extremely important for patients with large cranial defects. For these cases, preoperative fabrication of implants is recommended to avoid problems of donor site morbidity, sufficiency of donor material and quality. Finally, crafting the correct shape is a non-trivial task increasingly complicated by defect size.

Methods

We present a CAD tool to design such implants for the neurocranium. A combination of geometric morphometrics and radial basis functions, namely thin-plate splines, allows semiautomatic implant generation. The method uses symmetry and the best fitting shape to estimate missing data directly within the radiologic volume data. In addition, this approach delivers correct implant fitting via a boundary fitting approach.

Results

This method generates a smooth implant surface, free of sharp edges that follows the main contours of the boundary, enabling accurate implant placement in the defect site intraoperatively. The present approach is evaluated and compared to existing methods. A mean error of 89.29 % (72.64–100 %) missing landmarks with an error less or equal to 1 mm was obtained.

Conclusion

In conclusion, the results show that our CAD tool can generate patient-specific implants with high accuracy.

     

Control strategies for active lower extremity prosthetics and orthotics: a review

Technological advancements have led to the development of numerous wearable robotic devices for the physical assistance and restoration of human locomotion. While many challenges remain with respect to the mechanical design of such devices, it is at least equally challenging and important to develop strategies to control them in concert with the intentions of the user.This work reviews the state-of-the-art techniques for controlling portable active lower limb prosthetic and orthotic (P/O) devices in the context of locomotive activities of daily living (ADL), and considers how these can be interfaced with the user’s sensory-motor control system. This review underscores the practical challenges and opportunities associated with P/O control, which can be used to accelerate future developments in this field. Furthermore, this work provides a classification scheme for the comparison of the various control strategies.As a novel contribution, a general framework for the control of portable gait-assistance devices is proposed. This framework accounts for the physical and informatic interactions between the controller, the user, the environment, and the mechanical device itself. Such a treatment of P/Os – not as independent devices, but as actors within an ecosystem – is suggested to be necessary to structure the next generation of intelligent and multifunctional controllers.Each element of the proposed framework is discussed with respect to the role that it plays in the assistance of locomotion, along with how its states can be sensed as inputs to the controller. The reviewed controllers are shown to fit within different levels of a hierarchical scheme, which loosely resembles the structure and functionality of the nominal human central nervous system (CNS). Active and passive safety mechanisms are considered to be central aspects underlying all of P/O design and control, and are shown to be critical for regulatory approval of such devices for real-world use.The works discussed herein provide evidence that, while we are getting ever closer, significant challenges still exist for the development of controllers for portable powered P/O devices that can seamlessly integrate with the user’s neuromusculoskeletal system and are practical for use in locomotive ADL.     

Exercise training for lower limb amputees]

Lower limb amputee have lower exercise capacities, proportionally to the delay necessary to use their well-fitted prosthesis. Exercise training is a valid therapeutic to improve local factors (residual limb), muscle strength and endurance, locomotor performance and to decrease the cardiovascular risk factors. The programs for exercise training used for amputees are derivate from the vascular diseases and adapted (upper limb ergometer, cycloergometer with intact limb, pharmacological stress). Exercise training must be personalised because the population with lower limb amputation is very heterogeneous for deficiency and capacity (orthopaedic, vascular and cardiac) and for their socioprofessional project.     

Performance specification for lower limb orthotic devices

OBJECTIVE: To establish the range of forces and moments applied to lower limb orthoses during ambulation by routine users. DESIGN: Well-established gait analysis techniques were used to determine the loading at the major joints. It was assumed that the joint moments were transmitted by the orthosis encompassing any particular joint. Two hundred and five assessments of 164 patients were successfully completed by a consortium of four gait laboratories in Europe. The orthosis specification and patient clinical data were also recorded. BACKGROUND: The design and development of orthoses has occurred largely by evolution rather than by formal engineering methods. In particular, formal design has been hampered by a lack of information on the forces and moments applied during ambulation. METHODS: A standard gait analysis procedure was employed to capture the data. In-house biomechanical models were used to calculate the joint loading. Data were normalised with respect to patient weight and leg length. RESULTS: It was found that the median maximum normalised ankle moment transmitted by an ankle foot orthosis was 0.15 and the maximum knee moment was 0.09. The greatest moment transmitted by the hip joint of a hip knee ankle foot orthosis was also 0.09. There was a wide variation in the data due to differences in the impairments of the test subjects. CONCLUSION: It is possible to estimate the loads transmitted by an orthosis using established gait analysis procedures without the need for load measurement transducers. There is now a need both to collect a larger representative dataset and to perform validation studies with transducers.     

干细胞移植干预下肢缺血性疾病

目的:探讨干细胞移植在下肢缺血性疾病治疗中的应用情况。方法:检索Pubmed 1997-03/2007-03与干细胞移植治疗下肢缺血性疾病有关的文章,检索词为"stem cells,transplantation,limb ischemia",并限定文章语言种类为英语。同时检索中国期刊全文数据库1997-03/2007-03相关的文章,检索词为"干细胞移植,下肢缺血性疾病",并限定文章语言种类为中文。然后对资料进行初审,并查看每篇文献后的引文。纳入标准:文章所述内容应与干细胞移植在缺血性下胺血管中的应用研究相关;以近5年且发表在较权威杂志者优先。排除标准:重复研究或Meta分析类文章。结果:共收集到330篇相关文献,排除277篇内容陈旧或重复的文献,53篇符合纳入标准,有33篇检索到全文,纳入其中的26篇:16篇涉及骨髓干细胞移植;6篇涉及自体外周血干细胞移植,其余为其他相关文献。阐述干细胞具有多重分化活性,可有效改善下肢缺血。基础研究表明骨髓、外周血干细胞移植能使肢体侧支循环增加。干细胞参与血管形成的机制主要有直接分化、成熟为新血管以及分泌血管内皮细胞生长因子等促进局部缺血组织的血管新生。临床研究表明自体骨髓干细胞或自体外周血干细胞移值治疗下肢缺血性疾病部取得了较好的临床效果,但仍然存在移植安全性、远期治疗效果、提高临床疗效等问题。结论:干细胞移植能促进下肢血管新生,已成为治疗下肢缺血性疾病的有效方法之一。     

外骨骼康复机器人改善脑卒中偏瘫患者下肢功能的临床研究

目的：观察应用下肢外骨骼康复机器人康复训练对脑卒中偏瘫患者下肢功能的改善情况。方法：脑卒中偏瘫下肢运动功能障碍患者60例,分为机器人组和对照组各30例。对照组给予脑卒中常规康复治疗,机器人组在常规康复治疗的基础上,应用下肢外骨骼康复机器人进行康复训练。于训练前后通过 Fugl-Meyer运动及平衡功能评分、Holden步行功能分级对患者的下肢康复情况进行评价。结果：训练60d后,2组 Fugl-Meyer运动功能评分、Fugl-Meyer平衡功能评分、Holden步行功能分级均较治疗前明显提高（P＜0．05）,且机器人组提高幅度较对照组更显著（P＜0．05）。结论：应用下肢外骨骼康复机器人可改善脑卒中偏瘫患者的下肢功能,值得在临床上推广应用。     

New concepts in lower limb orthotics

Lower limb orthotics is in the process of a default transformation because of its association with lower limb prosthetics, a mechanical discipline that has translated component and material innovations into balance and velocity function gains to achieve a level of ambulation not possible a generation ago. This article discusses the fundamental mechanical similarities and differences of lower limb orthotics to prosthetics and their application to orthoses designed to improve the gait outcome of patients requiring orthotic intervention.     

下肢康复机器人联合虚拟现实技术对脑卒中患者下肢功能的影响

目的:探讨下肢康复机器人联合虚拟现实技术对脑卒中患者下肢功能的影响。方法:收集发病1—6个月的初发脑卒中偏瘫患者60例。根据患者是否接受下肢康复机器人治疗分为常规治疗组(CT组)、康复机器人组(RR组)和虚拟现实机器人组(VRR组)各20例。CT组接受常规康复治疗(2次/d,30min/次,5d/周,共4周);RR组、VRR组除常规康复治疗外(1次/d,30min/次,5d/周,共4周),同一天分别给予Lokomat下肢康复机器人治疗、Lokomat下肢康复机器人联合虚拟现实技术治疗(均为1次/d,30min/次,5次/周,共4周)。3组患者均在治疗前、治疗4周后采用Berg平衡量表(BBS)、Fugl-Meyer下肢运动功能量表(FMA-LE)、卒中患者运动功能评估量表(MAS)、功能性步行量表(FAC)进行评定。结果:治疗前,3组患者BBS、FMA-LE、MAS、FAC评分无显著性差异(P0.05)。治疗4周后,3组患者的BBS、FMALE、MAS和FAC的评分均较治疗前明显提高(P0.01),RR组、VRR组均较CT组评分有明显提高(P0.05),且VRR组较RR组的FMA-LE、MAS和FAC的评分也有明显提高(P0.05),但BBS评分比较无显著性差异(P0.05)。结论:下肢康复机器人联合虚拟现实技术能有效改善脑卒中患者的平衡能力、下肢运动功能、卒中后运动功能和步行能力。     

Care planning for children with lower limb amputation

This article explores the pathways of care for children who undergo lower limb amputation, from pre-surgery to rehabilitation. The consequences of surgery are manifold, including that children and their families must cope with life with a disability, effects on mobility, greater demands on metabolic reserve, disfigurement, pain and discomfort. Care can be divided into multidisciplinary pre-operative, post-operative, mid-term rehabilitation, including prosthetic limb casting and fitting, and long-term rehabilitation over many weeks and years. The involvement of the multidisciplinary team as the child progresses is described. It is recommended that care should be co-ordinated by a nominated lead professional. Effective discharge planning is crucial to a successful transition home and continuing rehabilitation.