Non-Coplanar Urinary Stent with Elastic Sleeve
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Solution Overview
Problem
Conventional Double-J and pigtail ureteral stents cause significant discomfort due to mechanical irritation of the bladder trigone and urine reflux, leading to symptoms like frequency, urgency, and flank pain, primarily due to their two-dimensional design and coplanar ends.
Innovation Solution
The design of the stent features non-coplanar ends with a luminary groove covered by a softer, radially elastic sleeve that adjusts with respiratory movements, minimizing friction with the trigone and preventing urine reflux by collapsing inward when bladder pressure increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional coplanar Double-J stent design is used, then anchoring capability is achieved, but mechanical irritation of the bladder trigone occurs causing discomfort
Solution Approach 1:
The patent transitions from a two-dimensional coplanar stent design to a three-dimensional non-coplanar configuration where the bladder end is oriented at an angle (e.g., 90 degrees) relative to the body axis. This dimensional change allows the stent to anchor effectively while directing the bladder end away from the trigone, eliminating mechanical irritation.
2Productivity
If conventional stent design is used, then urine drainage function is provided, but urine reflux from bladder to kidney occurs
Solution Approach 1:
The patent employs a dynamic sleeve component that can change its configuration in response to pressure changes. During normal drainage, the sleeve remains open to allow urine flow. When bladder pressure increases, the sleeve collapses inward to occlude the lumen and prevent reflux, providing an active pressure-responsive valve mechanism.
3Device complexity
If conventional coplanar design is used, then stent structure is simple, but frictional contact with trigone causes frequency and urgency symptoms
Solution Approach 1:
The patent introduces asymmetry in the stent geometry by orienting the bladder end at a non-coplanar angle (e.g., perpendicular) to the body axis. This asymmetric configuration naturally positions the bladder end away from the trigone region, reducing frictional contact and the associated symptoms of frequency and urgency.
4Ease of manufacture
If conventional stent design is used, then manufacturing is straightforward, but patient comfort is poor due to trigonal irritation
Solution Approach 1:
The patent achieves improved patient comfort by transitioning to a three-dimensional non-coplanar design. The angled orientation of the bladder end (e.g., 90 degrees from the body axis) redirects it away from the trigone, significantly reducing mechanical irritation and associated discomfort symptoms while remaining manufacturable.
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
This design significantly reduces stent-related discomfort by minimizing frictional contact with the trigone and preventing urine reflux, thereby alleviating symptoms of frequency, urgency, and flank pain.
Implementation Method 1
a sleeve of materials softer than the remainder of the stent, allowing urine at sufficient pressures to pass out from the stent, between the stent and the sleeve
Implementation Method 2
the sleeve is pre-shaped to collapse inward or it may collapse inward (toward the groove) to occlude the lumen when the pressure in the bladder increases, to prevent urine reflux from the bladder through the stent toward the kidney
Data Source
AI summary
A urinary stent includes ends for deployment in the kidney and bladder, respectively, that are non-coplanar. The bladder end of the stent includes a luminary groove, covered by a sleeve of materials softer than the remainder of the stent, allowing urine at sufficient pressures to pass out from the stent, between the stent and the sleeve. The bladder end of the stent adapts its shape according to respiratory changes in the length of the stent. This shape change also prevents or reduces stent related pain.