Longitudinally Reinforced Sheath for Stent Deployment
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Solution Overview
Problem
Conventional introducer sheaths with coiled or braided reinforcements tend to elongate during deployment of longer or coated medical interventional devices, such as stents, leading to inefficiencies in deployment due to increased resistance and potential failure to fully deploy the device.
Innovation Solution
A longitudinally reinforced sheath featuring a triaxial braid reinforcing member that inhibits elongation, maintaining a consistent inner diameter and facilitating efficient deployment of medical devices by resisting the radial expansive forces exerted by the stent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional coiled or braided reinforcements are used in the sheath, then the sheath can traverse tortuous pathways and provide kink resistance, but the sheath tends to elongate during deployment of longer or coated medical devices, increasing resistance and potentially preventing full deployment
Solution Approach 1:
The patent employs a composite reinforcement structure combining a braid layer and a coil layer. The braid provides longitudinal strength and torsional rigidity, while the coil provides radial strength and kink resistance. This composite structure resolves the contradiction by integrating the advantages of both reinforcement types to prevent elongation during deployment while maintaining navigability through tortuous pathways.
Solution Approach 2:
The reinforcement is segmented into distinct functional layers: an inner braid layer for longitudinal stability and an outer coil layer for radial support and kink prevention. This segmentation allows each layer to independently perform its specialized function, preventing the sheath from elongating during device deployment while maintaining the ability to navigate complex anatomical pathways.
2Length of moving object
If the sheath is made thinner to facilitate insertion through small incisions, then minimally invasive access is improved, but the sheath becomes more prone to kinking and ovalization during bending
Solution Approach 1:
The patent uses a composite reinforcement structure with braid and coil layers that provides exceptional kink resistance and structural integrity. This allows the sheath to be made with thinner walls for minimally invasive insertion while the composite reinforcement prevents kinking and ovalization during bending and manipulation in the tortuous pathways to the target site.
3Adaptability or versatility
If longer and/or greater diameter medical devices are deployed, then the ability to treat more extensive anatomy is improved, but the deployment forces increase, causing the sheath to stretch and reducing the distance the sheath handle travels
Solution Approach 1:
The composite braid-coil reinforcement structure provides the longitudinal and radial strength necessary to withstand the increased deployment forces generated by longer and/or greater diameter medical devices. This prevents sheath stretching and maintains the relationship between handle displacement and device deployment distance, enabling controlled deployment of extended-length devices.
Data Source
AI summary
A sheath for deploying a medical device to a target site in the body of a patient. A tubular inner liner has a proximal portion, a distal portion, and an outer surface. An outer jacket has a proximal portion, a distal portion, and an inner surface. A reinforcing member is received within a length of the outer jacket. The outer jacket is positioned longitudinally around the inner liner and bonded to the outer surface of the liner. The reinforcing member, which may be a triaxial braid, or an encapsulated longitudinal reinforcing wire, extends along the outer jacket length and is configured for inhibiting elongation of the sheath upon deployment of the device.