Implant Deployment Device Rotational Locking Mechanism
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Solution Overview
Problem
Prior implant deployment devices experience relative rotation issues between the sheath and the pusher member during implant placement, leading to incorrect implant orientation and potential twisting, due to unsatisfactory locking mechanisms that either restrict movement too much or increase the risk of jamming and kinking.
Innovation Solution
An implant deployment device with a sheath assembly and implant support element featuring generally round transverse cross-sections and co-operating guide and follower components, such as channels and projections, to prevent relative rotation while allowing for even flexibility and minimizing jamming risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a locking mechanism with grooves and ribs is used to prevent relative rotation, then rotational stability is improved, but axial movement freedom deteriorates
Solution Approach 1:
The locking mechanism is segmented into multiple independent features: circumferential grooves for rotational stability and longitudinal slots for axial movement freedom. This segmentation allows each feature to perform its specific function without interfering with the other, resolving the contradiction between rotational stability and axial movement freedom.
Solution Approach 2:
The locking mechanism uses asymmetric features - circumferential grooves that extend around the pusher rod provide rotational constraint, while longitudinal slots provide axial movement freedom. The asymmetric arrangement of these features allows differential movement control in different directions.
2Stability of the object's composition
If non-round cross-section sheaths are used to prevent relative rotation, then rotational control is improved, but flexibility and risk of kinking deteriorates
Solution Approach 1:
The sheath and pusher rod use round cross-sections instead of non-round shapes. This spherical/curved geometry provides uniform flexibility in all radial directions, eliminates stress concentration points that would cause kinking, while still allowing rotational control through the guide-follower mechanism.
Solution Approach 2:
A guide-follower mechanism acts as an intermediary between the round sheath and pusher rod to prevent relative rotation. The guide feature on the sheath and follower feature on the pusher rod work together to provide rotational control without requiring non-round cross-sections, thus maintaining flexibility and kinking resistance.
3Ease of operation
If the sheath is made flexible to pass through lumens, then ease of introduction is improved, but rotational torque transmission deteriorates
Solution Approach 1:
The guide-follower mechanism serves as an intermediary that couples the flexible sheath to the pusher rod, enabling torque transmission from the proximal end to the distal end. This mechanical coupling allows the flexible sheath to transmit rotational forces effectively without compromising its flexibility for navigation through lumens.
Data Source
AI summary
An implant deployment device (10) includes a pusher member (30), inner catheter (24), dilator tip (20) upon which an implant (18) is supported during deployment into a lumen of a patient. A sheath (32) substantially surrounds the pusher member (30), the inner catheter (24), the dilator tip (20), covering the implant (18) and containing the implant (18) therewithin. The pusher member (30), inner catheter (24), dilator tip (20) has at least one longitudinal groove formed in its outer surface. This engages with at least one tooth (112) formed in an inner surface of the sheath (32) or an inner surface of a component of the device that is attached to the sheath (32), such as a clamping collar (90) or a locking unit (100). The tooth (112) engages with a longitudinal groove (80) and is able to move along the groove (80) in a longitudinal direction. The engagement of the tooth (112) within the groove (80), however, prevents relative rotation between the sheath (32) and the pusher member (30), inner catheter (24), dilator tip (20). Twisting of an implant (18) supported on the inner catheter (24) is thus avoided.