Catheter Steering Control Apparatus Bidirectional Deflection
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Solution Overview
Problem
Steerable medical catheters require a reliable steering control apparatus to deflect the catheter tip in two different directions for precise positioning of therapy devices within the body, such as for cardiac arrhythmia treatment, but existing systems lack effective mechanisms for bidirectional deflection.
Innovation Solution
A steering control apparatus within the catheter handle includes a first and second wire extending from the distal end to the handle, with a steering assembly featuring cylindrical drums and a steering shaft, allowing for tension control in both wires to steer the catheter tip in two directions using a steering knob, and an optional brake assembly for maintaining deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a steering control apparatus is designed to deflect the catheter tip in two different directions, then the positioning precision of the therapy device is improved, but the device complexity increases
Solution Approach 1:
The steering control apparatus is segmented into two independent wire systems (first wire and second wire) that can be controlled separately. Each wire system connects to a dedicated drum (first drum and second drum) that can be independently actuated, allowing bidirectional deflection control without requiring a single complex steering mechanism
Solution Approach 2:
The first drum and second drum are arranged coaxially with the steering shaft, with the first drum nested around the steering shaft and the second drum nested around the first drum. This nested configuration allows both drums to rotate independently while sharing the same axial space, reducing the overall device complexity and footprint
2Ease of operation
If cylindrical drums are used to control wire tension, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The cylindrical drums serve multiple functions: they act as pulleys to redirect wire tension, as storage spools for the wires, and as rotational control elements that translate operator input into differential wire tension. The coaxial arrangement of both drums allows them to be actuated by a single rotational input from the operator, making the system easy to operate while maintaining functional complexity
Solution Approach 2:
The cylindrical shape of the drums provides a curved surface that naturally guides the wires around the steering shaft, creating mechanical advantage for tension control. The circular cross-section allows smooth rotation and consistent wire wrap geometry, improving ease of operation compared to angular or flat control surfaces
Data Source
AI summary
A steering control apparatus includes a first wire and a second wire extending from a distal end of a catheter to a steering assembly. The steering assembly includes a steering knob disposed at an exterior of the handle, a cylindrical steering shaft projecting from the steering knob and into the interior of the handle, a first cylindrical drum disposed within the handle and connected to the first wire, and a second cylindrical drum within the handle and connected to the second wire. The first drum is configured to engage the steering shaft to produce tension on the first wire. The first drum is coaxial with the steering shaft. The second drum is configured to engage the steering shaft to produce tension on the second wire. The second drum is coaxial with the steering shaft and axially adjacent to the first drum.