Steerable Medical Device Handle Cam Mechanism
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Solution Overview
Problem
Current steerable medical devices lack efficient mechanisms for precise manipulation and steering of tools like sheaths, catheters, and introducers, limiting their directional control and usability in medical procedures.
Innovation Solution
A handle system with a movable control assembly, cam, and sliders that translate control wires to deflect tools, allowing for rotational and translational movements to steer medical devices like sheaths, catheters, or introducers, enabling precise deflection in various directions through a cam and gear train or rack and pinion mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple handle structure is used, then device complexity is reduced, but steering precision and control capability deteriorate
Solution Approach 1:
The handle is divided into distinct functional modules: a control assembly for user input, a cam mechanism for motion conversion, sliders for directional control, and control wires for actuation. Each segment performs a specific function, allowing precise steering while maintaining manageable complexity through modular design
Solution Approach 2:
The cam mechanism serves as an intermediary between the control assembly and the sliders, converting rotational motion into linear motion. The control wires act as intermediaries transmitting force from the sliders to the elongate tool. These intermediary elements enable precise steering control without direct mechanical coupling, resolving the contradiction between simplicity and precision
2Measurement precision
If a cam and slider mechanism is added, then steering precision is improved, but device complexity increases
Solution Approach 1:
The cam and slider mechanisms are merged into a single integrated assembly where the cam rotates and simultaneously drives multiple sliders in coordinated motions. This merging reduces the number of separate mechanisms needed while maintaining precise deflection control in multiple directions through a unified motion conversion system
Solution Approach 2:
The cam mechanism serves multiple functions: it converts rotational motion to linear motion, controls the position of multiple sliders simultaneously, and enables bidirectional deflection control. This multi-functionality reduces overall device complexity by consolidating what would otherwise require separate mechanisms for each function
3Ease of operation
If control wires are used to deflect the tool, then maneuverability is improved, but reliability of wire tensioning and control deteriorates
Solution Approach 1:
The sliders are positioned and tensioned in advance before tool deflection is required. The control wires are pre-tensioned within the handle assembly, ensuring that when deflection is needed, the wires are already in the correct state to transmit force reliably. This preliminary preparation prevents wire slackness and ensures consistent control reliability
Solution Approach 2:
The control wire system is designed to self-tension through the cam and slider mechanism itself. As the cam rotates and drives the sliders, the wires automatically tension themselves without requiring separate tensioning mechanisms. The mechanical motion of the sliders directly creates the tension needed for reliable control, making the system self-regulating and more reliable
Data Source
AI summary
A steerable medical device includes a handle having a handle body and a first control assembly that is movable with respect to the handle body. A first cam is housed within the handle body and is coupled to the control assembly. Movement of the control assembly with respect to the handle body drives rotation of the cam with respect to the handle body. A first slider is housed within the handle body and is coupled to the cam. Rotation of the cam drives translation of the slider within the handle body. An elongate tool extends from the handle. A first control wire is coupled between the first slider and the tool. Translation of the first slider causes tensioning of the control wire, and tensioning of the control wire causes deflection of the tool.