Incremental Stent Delivery Handle for Controlled Sheath Retraction

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Solution Overview

Problem

Existing stent deployment systems lack precise control over the amount of proximal movement of the sheath, leading to accidental full deployment or premature retraction, often requiring multiple users or hands to operate, and result in undesirable stent placement.

Innovation Solution

A device with a handle and deployment assembly that allows incremental, controlled deployment and reconstrainment of a stent using a rack and gear mechanism, enabling single-handed operation with incremental steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the sheath is retracted proximally without restriction to deploy the stent, then the stent deployment is simple and quick, but the control over the amount of proximal movement is poor leading to accidental full deployment or premature retraction

Engineering Contradiction:

Improvestent deployment operationVSAvoidcontrol over proximal movement

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The deployment assembly is segmented into multiple independent components: a handle, an inner member, a sheath, and a rack-gear mechanism. The rack-gear mechanism divides the continuous retraction motion into discrete incremental steps, allowing precise control over sheath movement while maintaining operational simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rack-gear mechanism acts as an intermediary between the user's manual operation and the sheath movement. This intermediary mechanism translates unrestricted manual retraction into controlled incremental steps, providing both ease of operation and precise measurement of proximal movement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a mechanism is added to control sheath retraction in incremental steps, then the control precision is improved, but the device complexity increases and may require multiple users or hands

Engineering Contradiction:

Improvecontrol over proximal movementVSAvoiddeployment mechanism

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The rack-gear mechanism is designed to be self-regulating and self-explanatory through its mechanical structure. The engagement of rack teeth with gear teeth automatically provides incremental control without requiring external guidance or multiple operators. The mechanism serves itself by converting any manual retraction force into precise incremental steps.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex electronic or computerized control systems with a purely mechanical rack-gear mechanism. This mechanical substitution achieves precise incremental control through simple, reliable mechanical engagement, reducing device complexity while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the sheath can be retracted freely, then the procedure is faster, but the risk of accidental deployment in undesirable location increases

Engineering Contradiction:

Improvedeployment speedVSAvoidaccurate stent placement

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The rack-gear mechanism is pre-configured with multiple engagement positions that correspond to specific incremental steps of sheath retraction. This preliminary arrangement of mechanical elements ensures that as the user retracts the sheath, the stent deployment progresses through predetermined stages, allowing time for verification and correction before final deployment, thus maintaining both speed and reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mechanical engagement of the rack-gear mechanism provides inherent feedback through the tactile sensation of tooth engagement and the visible progression of incremental steps. This feedback allows the operator to monitor sheath retraction and stent deployment in real-time, ensuring accurate placement while maintaining procedural efficiency.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Provides precise control over stent deployment and reconstrainment, allowing single-user operation and reducing the risk of accidental full deployment or retraction, enhancing procedural accuracy.

Implementation Method 1

A rack and gear mechanism enables the deployment member to be translated in incremental steps along a deployment axis

Methodology Applied

Scientific EffectRack and pinion mechanism: Rack and Pinion

Implementation Method 2

A first one-way bearing may be coupled to the first gear and may be axially disposed about and coupled to the drive shaft. The first bearing may be configured to prevent the first gear from imparting a rotary motion to the drive shaft that translates the deployment member in the first direction.

Methodology Applied

Scientific EffectOne-way bearing mechanism:

Data Source

PatentUS12551359B2Devices and methods for controlled delivery of a stent

Publication Date: 2026.02.17 BOSTON SCIENTIFIC SCIMED INC

AI summary

The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to devices and methods for controlled delivery of a stent, such as a self-expanding stent, and more particularly for controlling the full deployment of a stent in incremental steps from a sheath and for controlling the reconstrainment of a stent in incremental steps within a sheath.