Nested Introducer Sleeve Shielding Stiffening Cannula
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Solution Overview
Problem
Existing percutaneous access systems using small gauge needles for vascular procedures face challenges in maintaining rigidity for inserting through tough tissues without causing trauma, as stiffening cannulas can protrude and cause tissue damage when encountering fibrous tissues or calcifications.
Innovation Solution
The system engages the inner sleeve and stiffening cannula to inhibit relative axial movement, ensuring the cannula remains shielded by the inner sleeve during insertion, preventing direct exposure and trauma to tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stiffening cannula is used to maintain rigidity during insertion through tough tissues, then the rigidity of the insertion system is improved, but the cannula may protrude and cause tissue trauma when encountering fibrous tissues or calcifications
Solution Approach 1:
The inner sleeve acts as an intermediary protective element between the stiffening cannula and the tissue. It shields the cannula during insertion through tough tissues and prevents direct contact between the cannula and tissue, thereby maintaining rigidity while preventing trauma
Solution Approach 2:
The insertion system is divided into multiple functional segments: an outer needle for initial puncture, an inner sleeve for protection and transition, and a stiffening cannula for rigidity support. Each segment performs a specific function and can be independently optimized
2Object-affected harmful factors
If a small gauge needle is used to minimize tissue damage, then the harm to tissue is reduced, but the bore is not large enough to pass a standard 0.035 inch or larger wire guide through
Solution Approach 1:
The small gauge needle creates the initial puncture pathway through the skin and tissue before the larger components are introduced. This preliminary action allows subsequent passage of larger wire guides and catheters through the established tract
Solution Approach 2:
Multiple components are nested within each other: the wire guide passes through the needle bore, the inner sleeve contains the wire guide, and the outer needle contains the inner sleeve. This nested arrangement allows progressive introduction of components with different diameter requirements
Data Source
AI summary
An apparatus for providing percutaneous access to a vessel of a patient over a wire guide. An outer sleeve of the apparatus has proximal and distal open ends, and has a lumen extending longitudinally therethrough. An inner sleeve has proximal and distal open ends, and has a lumen extending longitudinally therethrough. The inner sleeve is sized to be received within the lumen of the outer sleeve. The inner sleeve has a main body portion having a distal portion that tapers toward its distal open end. The tapered distal portion extends distal to the distal open end of the outer sleeve to provide a generally smooth diametrical transition between the outer sleeve and the wire guide. A more rigid stiffening cannula has proximal and distal open ends, and has a lumen extending longitudinally therethrough. The lumen of the stiffening cannula is sized to receive the wire guide therethrough. The stiffening cannula is sized to be received within the lumen of the inner sleeve, and extends along the main body portion of the inner sleeve to a terminal point proximal to the inner sleeve distal end. The stiffening cannula and the inner sleeve are engaged such that relative axial movement between them is substantially inhibited. As a result, the inner sleeve distal portion acts as a shield for the distal end of the stiffening cannula distal end when the apparatus is percutaneously introduced into the vessel.