FES Orthosis with Spring-Loaded C-Frame for Easy Donning
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Solution Overview
Problem
Current FES orthosis devices face challenges such as difficulty in donning by patients with impaired hands, limited adaptability to different limb sizes, discomfort due to high skin current density, and the need for precise electrode positioning, which restricts their widespread use and effectiveness.
Innovation Solution
A semi-rigid, C-shaped frame with flexible retaining elements and large surface area electrodes that can be easily donned and secured on the limb, featuring a locking mechanism and a neuroprosthetic stimulator unit integrated within the orthosis, allowing for adjustable positioning and reduced skin sensory discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If prior art FES orthosis devices are used, then muscle activation is achieved, but the devices are difficult to don by patients with impaired hands due to precise fitting requirements and multiple components
Solution Approach 1:
The patent combines the electrode assembly, retaining elements, and frame into an integrated orthosis structure where electrodes are pre-positioned on the frame with spring-loaded retaining elements that automatically secure the limb. This integration eliminates the need for separate electrode placement and securing steps, enabling patients to don the device independently despite hand impairments.
Solution Approach 2:
The spring-loaded retaining elements automatically engage with the limb upon insertion, providing self-retaining functionality that secures the orthosis without requiring manual adjustment or assistance. The design allows the device to serve itself during the donning process, reducing the operational burden on patients with limited hand function.
2Adaptability or versatility
If prior art FES orthosis devices are used, then electrode positioning is achieved, but the devices lack adaptability to different limb sizes and shapes
Solution Approach 1:
The frame incorporates spring-loaded retaining elements that provide dynamic adjustment capability, allowing the orthosis to adapt to various limb circumferences and shapes. The spring mechanism enables the retaining elements to compress and expand, maintaining secure contact with different limb sizes while preserving accurate electrode positioning through the flexible yet positionally stable frame structure.
Solution Approach 2:
The design allows adjustment of the frame's retaining elements through parameter changes in spring compression and positioning, enabling the same device to accommodate different limb dimensions. The spring-loaded mechanism provides variable retention force that can be adjusted to match different anatomical variations while maintaining electrode alignment.
3Object-affected harmful factors
If prior art FES orthosis devices are used, then muscle stimulation is achieved, but skin sensory discomfort occurs due to high current density from small electrodes
Solution Approach 1:
The patent transitions from small point-contact electrodes to large surface area electrodes that distribute stimulation current across an extended area. This dimensional change from zero-dimensional points to two-dimensional surfaces reduces current density while maintaining total stimulation power, thereby eliminating skin sensory discomfort without compromising muscle activation effectiveness.
Solution Approach 2:
The design changes the physical parameter of electrode surface area from small to large, which directly reduces current density (current per unit area). This parameter change allows the delivery of the same total stimulation power with lower intensity distribution across the skin surface, eliminating discomfort while preserving therapeutic effectiveness.
4Ease of manufacture
If prior art FES orthosis devices are used, then gait modulation is achieved, but the devices require considerable expertise to reconfigure for different patients
Solution Approach 1:
The orthosis is designed with universal adaptability through adjustable retaining elements and repositionable electrode assemblies that can accommodate different patient anatomies without requiring custom fabrication. The frame structure and spring-loaded mechanism provide multi-functional capability to serve various limb sizes and shapes, enabling easy reconfiguration between patients while maintaining precise electrode positioning through standardized adjustment procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables easy and accurate donning by patients with impaired hands, improved muscle activation with reduced discomfort, and adaptability to various limb sizes, enhancing the orthosis's usability and effectiveness in gait modulation.
Implementation Method 1
the opposing retaining elements are configured to be radially spring-loaded towards a center of the frame, such that in donning the orthosis around the limb segment, the limb segment applies a counter-pressure from within the frame, against the opposing retaining elements
Implementation Method 2
In FES, precisely timed bursts of short electrical pulses are applied to motor nerves, to generate muscle contraction, which can be applied to enhancing limb function
Data Source
AI summary
A functional electrical stimulation (FES) orthosis for FES to a limb segment, including: (a) a semi-rigid, self-retaining C-shaped frame, the frame configured to substantially envelop the limb segment, the frame including a first flexible and elongated circumferentially retaining element and at least a first and a second opposing flexible and elongated circumferentially retaining elements disposed on the circumferentially opposite side of the frame, the first retaining element and the first opposing retaining element forming a pair of opposing retaining elements, and (b) a surface electrical stimulation electrode for contacting at least one stimulation point on a surface of the limb segment, associated with, and supported by, the frame, the surface electrode for electrically associating, via the frame, with a neuroprosthetic stimulator unit, so as to provide FES, wherein the opposing retaining elements are configured to be radially spring-loaded towards a center of the frame, such that in donning the orthosis around the limb segment, the limb segment applies a counter-pressure from within the frame, against the opposing retaining elements, such that the orthosis is firmly and fixedly self-retained in a pre-determined position on the surface.