A passive mechanism for decoupling energy storage and return in ankle-foot prostheses: A case study in recycling collision energy.

Individuals with lower limb amputation experience reduced ankle push-off work in the absence of functional muscles spanning the joint, leading to decreased walking performance. Conventional energy storage and return (ESR) prostheses partially compensate by storing mechanical energy during midstance and returning this energy during the terminal stance phase of gait. These prostheses can provide approximately 30% of the push-off work performed by a healthy ankle-foot during walking.

Design of a 3D-printed hand prosthesis featuring articulated bio-inspired fingers.

Various upper-limb prostheses have been designed for 3D printing but only a few of them are based on bio-inspired design principles and many anatomical details are not typically incorporated even though 3D printing offers advantages that facilitate the application of such design principles. We therefore aimed to apply a bio-inspired approach to the design and fabrication of articulated fingers for a new type of 3D printed hand prosthesis that is body-powered and complies with basic user requirements. We first studied the biological structure of human fingers and their movement control mechanisms in order to devise the transmission and actuation system.

A Case Study With Symbihand: An sEMG-Controlled Electrohydraulic Hand Orthosis for Individuals With Duchenne Muscular Dystrophy.

With recent improvements in healthcare, individuals with Duchenne muscular dystrophy (DMD) have prolonged life expectancy, and it is therefore vital to preserve their independence. Hand function plays a central role in maintaining independence in daily living. This requires sufficient grip force and the ability to modulate it with no substantially added effort.

Perception and control of low cable operation forces in voluntary closing body-powered upper-limb prostheses.

Operating a body-powered prosthesis can be painful and tiring due to high cable operation forces, illustrating that low cable operation forces are a desirable design property for body-powered prostheses. However, lower operation forces might negatively affect controllability and force perception, which is plausible but not known. This study aims to quantify the accuracy of cable force perception and control for body-powered prostheses in a low cable operation force range by utilizing isometric and dynamic force reproduction experiments.

Functional evaluation of a non-assembly 3D-printed hand prosthesis.

In developing countries, the access of amputees to prosthetic devices is very limited. In a way to increase accessibility of prosthetic hands, we have recently developed a new approach for the design and 3D printing of non-assembly active hand prostheses using inexpensive 3D printers working on the basis of material extrusion technology. This article describes the design of our novel 3D-printed hand prosthesis and also shows the mechanical and functional evaluation in view of its future use in developing countries.

Simplifying models and estimating grasp performance for comparing dynamic hand orthosis concepts.

While designing a dynamic hand orthosis to assist during activities of daily living, the designer has to know whether a concept will have sufficient grasp performance to support these activities. This is often estimated by measuring the interaction force at the contact interface. However, this requires a prototyping step and limits the practicality of comparing several concepts in an early design stage.

A passive wrist with switchable stiffness for a body-powered hydraulically actuated hand prosthesis.

State of art upper limb prostheses lack several degrees of freedom (DoF) and force the individuals to compensate for them by changing the motions of their arms and body. Such movements often yield to articulation injuries, nonetheless these could be prevented by adding DoFs, for instance, an articulated passive wrist. Available stiff or compliant wrists with passive flexion/extension and/or radial/ulnar deviation are sub-optimal solutions.

Exploratory design of a compliant mechanism for a dynamic hand orthosis: Lessons learned.

This study does not describe a success-story. Instead, it describes an exploratory process and the lessons learned while designing a compliant mechanism for a dynamic hand orthosis. Tools from engineering optimization and rapid prototyping techniques were used, with the goal to design a mechanism to compensate for hypertonic or contracted finger muscles.

Design of a cosmetic glove stiffness compensation mechanism for toddler-sized hand prostheses.

The addition of a cosmetic glove to an upper limb prosthesis has a distinct effect on the cosmetic value, but its viscoelastic behaviour adds a substantial amount of stiffness and hysteresis to the system. As a result, the overall usability of the prosthesis is degraded. A novel negative stiffness element is designed to compensate for the cosmetic glove's stiffness.

Fatigue-free operation of most body-powered prostheses not feasible for majority of users with trans-radial deficiency.

Background: Body-powered prostheses require cable operation forces between 33 and 131 N. The accepted upper limit for fatigue-free long-duration operation is 20% of a users' maximum cable operation force. However, no information is available on users' maximum force.

Ipsilateral Scapular Cutaneous Anchor System: An alternative for the harness in body-powered upper-limb prostheses.

Background: Body-powered prosthesis users frequently complain about the poor cosmesis and comfort of the traditional shoulder harness. The Ipsilateral Scapular Cutaneous Anchor System offers an alternative, but it remains unclear to what extent it affects the perception and control of cable operation forces compared to the traditional shoulder harness.

Objective: To compare cable force perception and control with the figure-of-nine harness versus the Ipsilateral Scapular Cutaneous Anchor System and to investigate force perception and control at different force levels.

Passive prosthetic hands and tools: A literature review.

Background: The group of passive prostheses consists of prosthetic hands and prosthetic tools. These can either be static or adjustable. Limited research and development on passive prostheses has been performed although many people use these prosthesis types.

High Cable Forces Deteriorate Pinch Force Control in Voluntary-Closing Body-Powered Prostheses.

Background: It is generally asserted that reliable and intuitive control of upper-limb prostheses requires adequate feedback of prosthetic finger positions and pinch forces applied to objects. Body-powered prostheses (BPPs) provide the user with direct proprioceptive feedback. Currently available BPPs often require high cable operation forces, which complicates control of the forces at the terminal device.

Learning to use a body-powered prosthesis: changes in functionality and kinematics.

Background: Little is known about action-perception learning processes underlying prosthetic skills in body-powered prosthesis users. Body-powered prostheses are controlled through a harness connected by a cable that might provide for limited proprioceptive feedback. This study aims to test transfer of training basic tasks to functional tasks and to describe the changes over time in kinematics of basic tasks of novice body-powered prosthesis users.

A structured overview of trends and technologies used in dynamic hand orthoses.

The development of dynamic hand orthoses is a fast-growing field of research and has resulted in many different devices. A large and diverse solution space is formed by the various mechatronic components which are used in these devices. They are the result of making complex design choices within the constraints imposed by the application, the environment and the patient's individual needs.

Steerable Catheters in Cardiology: Classifying Steerability and Assessing Future Challenges.

Objective: This review aims to provide a structured classification of the underlying steering mechanisms in steerable catheters and to assess their future challenges.

Methods: Existing, patented, and experimental designs of steerable catheters are classified with respect to their steerability. Subsequently, the classification is used as a tool for defining future requirements and challenges for steerable cardiac catheters.

Assessment of body-powered upper limb prostheses by able-bodied subjects, using the Box and Blocks Test and the Nine-Hole Peg Test.

Background: The functional performance of currently available body-powered prostheses is unknown.

Objective: The goal of this study was to objectively assess and compare the functional performance of three commonly used body-powered upper limb terminal devices.

Study Design: Experimental trial.

The lightweight Delft Cylinder Hand: first multi-articulating hand that meets the basic user requirements.

Rejection rates of upper limb prostheses are high (23%-45%). Amputees indicate that the highest design priority should be reduction of the mass of the prosthetic device. Despite all efforts, the mass of the new prosthetic hands is 35%-73% higher than that of older hands.

Design and evaluation of two different finger concepts for body-powered prosthetic hand.

The goal of this study was to find an efficient method of energy transmission for application in an anthropomorphic underactuated body-powered (BP) prosthetic hand. A pulley-cable finger and a hydraulic cylinder finger were designed and tested to compare the pulley-cable transmission principle with the hydraulic cylinder transmission principle. Both fingers had identical dimensions and a low mass.

Comparison of mechanical properties of silicone and PVC (polyvinylchloride) cosmetic gloves for articulating hand prostheses.

Current articulating electric and body-powered hands have a lower pinch force (15-34 N) than electric hands with stiff fingers (55-100 N). The cosmetic glove, which covers a hand prosthesis, negatively affects the mechanical efficiency of a prosthesis. The goal of this study is to mechanically compare polyvinylchloride (PVC) and silicone cosmetic gloves and quantify the stiffness of the finger joints, the required actuation energy, and the energy dissipation during joint articulation.

A mechanism to compensate undesired stiffness in joints of prosthetic hands.

Background: Cosmetic gloves that cover a prosthetic hand have a parasitic positive stiffness that counteracts the flexion of a finger joint.

Objectives: Reducing the required input torque to move a finger of a prosthetic hand by compensating the parasitic stiffness of the cosmetic glove.

Study Design: Experimental, test bench.

Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development?

Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO) prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades.

Endoscope shaft-rigidity control mechanism: "FORGUIDE".

Recent developments in flexible endoscopy and other fields of medical technology have raised the need for compact slender shafts that can be made rigid and compliant at will. A novel compact mechanism, named FORGUIDE, with this functionality was developed. The FORGUIDE shaft rigidifies due to friction between a ring of cables situated between a spring and an inflated tube.

Efficiency of voluntary closing hand and hook prostheses.

The Delft Institute of Prosthetics and Orthotics has started a research program to develop an improved voluntary closing, body-powered hand prosthesis. Five commercially available voluntary closing terminal devices were mechanically tested: three hands [Hosmer APRL VC hand, Hosmer Soft VC Male hand, Otto Bock 8K24] and two hooks [Hosmer APRL VC hook, TRS Grip 2S]. The test results serve as a design guideline for future prostheses.

Design, fabrication, and preliminary results of a novel below-knee prosthesis for snowboarding: A case report.

Snowboarding with a below-knee prosthesis is compromised by the limited rotation capabilities of the existing below-knee prostheses, which are designed for use in normal walking. Based on snowboarding range of motion analyses, a novel below-knee prosthesis was designed with the aim to achieve similar range of motions like able-bodied snowboarders. The new prosthesis allows for passive inversion/eversion, passive plantarflexion/dorsiflexion and additional 'voluntary' plantarflexion/dorsiflexion initiated by lateral or medial rotation of the upper leg and knee.