Artificial Contractile Sphincter Pulsatile Constriction
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Solution Overview
Problem
Current artificial sphincters for urinary incontinence face issues such as tissue erosion, atrophy, and mechanical failures due to constant pressure, leading to inadequate solutions for long-term implantation without causing tissue necrosis or incontinence.
Innovation Solution
An artificial contractile sphincter designed to pulsatorily and alternately constrict the urethra in distinct regions, maintaining a temperature increase of less than 1°C above normal body temperature, with a hinged clamp or U-shaped structure and an activator that adjusts pressure to minimize tissue damage and leaking, powered by a low-energy source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant pressure is applied by the artificial sphincter to close the urethra, then incontinence is prevented, but tissue erosion and atrophy occur
Solution Approach 1:
The artificial sphincter applies periodic contractions rather than constant pressure. The contraction phase closes the urethra to prevent incontinence, followed by a relaxation phase that allows tissue recovery. This periodic action pattern prevents cumulative tissue damage while maintaining continence control.
Solution Approach 2:
The sphincter transitions from a static constant-pressure design to a dynamic system that alternates between contraction and relaxation states. This dynamic operation allows the device to adapt its pressure application over time, preventing tissue atrophy and erosion that occur with sustained constant pressure.
2Ease of operation
If shape memory alloy elements are heated to open the sphincter, then the constricting force is lost, but tissue burns and necrosis occur
Solution Approach 1:
The patent changes the activation mechanism from thermal heating to electrical stimulation. Shape memory alloy elements are activated by electrical currents that induce phase transformation without significant heat generation, avoiding tissue burns and necrosis while still achieving sphincter opening.
Solution Approach 2:
The thermal activation system is replaced with an electrical activation system. Instead of using heat to trigger shape memory alloy contraction, electrical currents are applied to induce the phase transformation, eliminating the harmful thermal effects on surrounding tissues.
3Reliability
If the sphincter remains closed in case of mechanical failure, then continence is maintained, but life-threatening complications occur
Solution Approach 1:
The failure mode is inverted from the traditional design. Instead of the sphincter remaining closed upon failure (which causes urinary retention and life-threatening complications), the design ensures that failure results in the sphincter opening, allowing urine passage while maintaining continence control through active activation when needed.
Solution Approach 2:
The system incorporates a safety mechanism that prevents the harmful failure mode of sustained closure. By designing the failure state to default to opening rather than closing, the system cushions against life-threatening complications before they can occur.
4Reliability
If high pressure is applied to ensure complete closure, then leaking is prevented, but tissue necrosis occurs
Solution Approach 1:
High pressure is applied only during the contraction phase to prevent leaking, followed by a relaxation phase that reduces pressure to prevent tissue necrosis. This periodic high-low pressure cycle maintains sealing effectiveness while protecting tissue health.
Solution Approach 2:
The pressure parameter is dynamically changed over time rather than maintained at a constant high level. The system alternates between high pressure for sealing and low pressure for tissue protection, achieving both leaking prevention and tissue health maintenance.
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
The solution effectively prevents tissue erosion and burn, ensuring long-term implantation with reduced health care costs and improved quality of life by maintaining sphincter muscle function and minimizing incontinence.
Implementation Method 1
EP 1 238 638 describes an artificial sphincter having an opening/closing portion for opening and closing, wherein said opening/closing portion has: a pair of elongated shape memory alloy elements that change reversibly between opposite shapes upon changes in temperature
Implementation Method 2
When the shape memory alloy elements are heated, they change shape, so that the constricting force on the intestine is lost
Implementation Method 3
maintaining a temperature increase of less than 1°C above normal body temperature
Data Source
Figure 1~6
Figure 2~3
Figure 4~5
AI summary
Sphincter generally devised to be used in the medical field for control of urinary incontinence and comprising a structure (1) adapted to be placed around the urethra. The structure (1) is designed to contract the urethra in at least two distinct regions in a pulsatory and alternately manner, and in such a way that the temperature of fluids or tissues surrounding the urethra does not increase above 40°C.