Multi-Layer Introducer Sheath Hub for Controlled Splitting
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Solution Overview
Problem
The increased size and complexity of percutaneous heart pumps require larger introducer sheaths, which are difficult to split due to higher break forces, leading to potential damage or discomfort during separation, and existing introducer sheaths are unreliable in fracturing the hub.
Innovation Solution
A multi-layer introducer sheath hub with a soft first hub portion and a stiff second hub portion, featuring notches and wings for leverage, reduces the break force required for splitting by distributing the force effectively and minimizing elastic energy release, allowing for larger introducer sheaths to be used safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the introducer sheath size is increased to accommodate larger heart pumps, then the pump capacity and sophistication are improved, but the break force required to split the hub increases making it difficult and unreliable to fracture
Solution Approach 1:
The hub is divided into two distinct portions: a first hub portion made of soft material with low ultimate strength that is designed to fracture, and a second hub portion made of stiff material that provides structural support. This segmentation allows the introducer sheath to be larger while maintaining reliable breakability by concentrating the fracture function in the softer first portion.
Solution Approach 2:
Different regions of the hub have different material properties tailored to their specific functions. The first hub portion has soft, low-strength material optimized for fracturing, while the second hub portion has stiff, high-strength material optimized for providing leverage and structural integrity during the breaking process.
2Adaptability or versatility
If the break force is increased to enable use of larger introducer sheaths, then the sheath size capability is improved, but the reliability of hub fracturing decreases and abrupt breaks may occur
Solution Approach 1:
The hub is pre-configured with notches in the first hub portion that concentrate stress and initiate fracture at predetermined locations. This preliminary preparation ensures that when force is applied to the second hub portion, the fracture occurs reliably at the intended location rather than unpredictably elsewhere.
Solution Approach 2:
The first hub portion acts as an intermediary element between the user's manual force applied to the second hub portion and the actual fracture event. It transforms the applied force into a controlled fracture through its low-strength material properties and pre-formed notches, ensuring reliable and predictable breaking.
3Ease of operation
If the hub material is made stiffer to provide better leverage for breaking, then the mechanical advantage is improved, but the elastic energy storage increases causing sudden release that may damage the pump or injure the physician
Solution Approach 1:
The hub is segmented into a stiff second portion that provides leverage and a soft first portion that absorbs and dissipates elastic energy. This segmentation allows the system to have both the mechanical advantage of stiff material and the safety of low elastic energy storage, as the soft first portion prevents dangerous energy accumulation while the stiff second portion enables effective breaking.
Solution Approach 2:
The potentially harmful effect of elastic energy storage in stiff materials is converted into a benefit by using the stiff second hub portion to provide leverage while the soft first hub portion safely dissipates the energy. The stiff material's tendency to store energy is harnessed to provide breaking force, while the soft material prevents dangerous energy release.
Data Source
AI summary
An introducer assembly includes an elongate sheath sized for insertion into a blood vessel of a patient and a hub. The hub can be coupled to a proximal portion of the sheath and can include a first hub portion and a second hub portion. The hub can include various features to facilitate breaking apart or separating the introducer assembly from a patient. For example, the first hub portion can have a first notch which can facilitate breaking, splitting, or fracturing the hub. The second hub portion can partially surround the first hub portion and can include two wings and an opening disposed above the first notch. The first hub portion can be formed from a first material and second hub portion can be formed from a second material. In some embodiments, the second material can be stiffer than the first material to facilitate fracturing the hub.