Flanged Dilator–Sheath Coupling for Stable Cardiac Access
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Solution Overview
Problem
Existing devices for creating punctures or perforations in heart tissue, such as the Brockenbrough™ Needle and radiofrequency perforation apparatuses, face challenges in securely coupling with therapy sheaths and maintaining alignment during medical procedures, leading to potential misalignment and loss of access.
Innovation Solution
A dilator and sheath system featuring a dilator hub with a flange and sheath hub design that inhibits relative rotation and includes an axial lock feature, utilizing a symmetric and asymmetric shape alignment and an annular protrusion to secure the dilator within the sheath, preventing axial disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple coupling mechanism is used between dilator and sheath, then device complexity is reduced, but coupling stability and alignment precision deteriorate
Solution Approach 1:
The flange on the dilator hub and the corresponding recess in the sheath hub feature asymmetric geometries with specific protrusions and angled surfaces. This asymmetric design prevents relative rotation between the dilator and sheath while maintaining a relatively simple coupling structure, thereby improving coupling stability without significantly increasing device complexity.
Solution Approach 2:
The coupling mechanism incorporates curved or angled surfaces on the flange and recess structures. These curved surfaces facilitate smooth engagement and rotational constraint between the dilator and sheath, enhancing coupling stability through geometric interlocking rather than complex mechanical fasteners.
2Ease of operation
If the dilator and sheath are coupled without rotational inhibition, then ease of operation is improved, but alignment precision and therapy delivery accuracy deteriorate
Solution Approach 1:
The asymmetric flange and recess design with specific protrusions and angled surfaces creates a self-aligning coupling mechanism. During assembly, the asymmetric geometries guide the components into correct alignment while preventing rotation, thereby achieving both ease of operation and high alignment precision simultaneously.
Solution Approach 2:
The coupling mechanism is segmented into distinct features on the dilator hub (flange with protrusions) and sheath hub (recess with corresponding surfaces). This segmentation allows each component to have specialized geometric features that work together to provide rotational constraint and alignment guidance, maintaining operational simplicity while ensuring precision.
3Ease of manufacture
If axial locking is not implemented, then ease of manufacture is improved, but reliability of maintaining access deteriorates
Solution Approach 1:
The axial lock feature utilizes an angled surface on the flange that interfaces with a corresponding surface on the sheath hub. This angled geometric relationship creates a mechanical stop that prevents axial disengagement through simple geometric interlocking, maintaining reliability without requiring complex locking mechanisms or additional fastening components.
Data Source
AI summary
A system for facilitating access to a patient's heart includes a sheath having a sheath body defining a lumen adapted to receive a dilator. The sheath body includes a proximal portion and a distal portion. A sheath hub is coupled to the proximal portion of the sheath. The sheath hub includes an opening. The system includes a dilator having a dilator shaft defining a lumen adapted to receive and support a puncturing device. The dilator shaft includes a proximal portion for manipulation by a user and a tapered distal portion for placement in or near the heart. A dilator hub is coupled to the proximal portion of the dilator shaft. The dilator hub includes a flange configured to be received in the opening. The opening and the flange include a symmetric shape along a vertical axis and an asymmetric shape along a horizontal axis.