Pedicle Screw Coupling Instrument With Ramp-Guided Release

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Solution Overview

Problem

Existing instruments for vertebral manipulation with polyaxial pedicle screws face challenges in reliably applying forces while maintaining a simple design and easy release of the locking engagement without additional tools, often resulting in complications due to self-locking mechanisms and elastic deformation.

Innovation Solution

A medical instrument with a coupling unit that allows for a detachable connection to the pedicle screw, featuring a ramp structure that guides the coupling arms to release the locking engagement through distal movement, enabling easy detachment without additional tools, and incorporating pre-tensioned, elastically deformable arms to ensure precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a self-locking locking mechanism is used to maintain stable connection during vertebral manipulation, then the reliability of force transmission is improved, but the ease of operation for releasing the locking engagement deteriorates (requiring additional tools)

Engineering Contradiction:
Improvereliability of force transmissionVSAvoidease of release of locking engagement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking arms are designed to be elastically deformable, transitioning between a locked position (engaged with the pedicle screw) and an unlocked position (disengaged). The elastic deformation allows the locking arms to be moved laterally by distal force application, dynamically changing the locking state without additional tools

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The ramp structure serves as an intermediary mechanism that converts distal linear movement into lateral displacement of the locking arms. This intermediary structure enables the release of the self-locking mechanism through a simple distal push, eliminating the need for additional release tools while maintaining reliable locking during manipulation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the coupling unit is designed with a simple structure for easy operation, then the device complexity is reduced, but the reliability of maintaining precise alignment during manipulation deteriorates

Engineering Contradiction:
Improvesimplicity of coupling unit designVSAvoidalignment precision during manipulation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The pre-tensioned elastic locking arms automatically self-align with the pedicle screw upon engagement. The elastic pre-tension ensures that the locking arms maintain constant contact and precise alignment with the screw throughout the manipulation process, without requiring additional alignment mechanisms or complex adjustment devices

Inventive Principle:
Principle #25Self-service

3Ease of operation

If additional tools are provided for releasing the locking engagement, then the ease of operation for release is improved, but the device complexity and number of components increases

Engineering Contradiction:
Improveease of release of locking engagementVSAvoidnumber of tools required
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The release function is extracted from a separate tool and integrated into the instrument's own structure through the ramp mechanism. The instrument can release its own locking engagement using its distal end, eliminating the need for additional release tools while maintaining easy operation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The instrument performs its own release function through the integrated ramp structure that converts distal movement into lateral displacement of locking arms. This self-service capability eliminates dependency on external tools for releasing the locking engagement

Inventive Principle:
Principle #25Self-service

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

The instrument facilitates reliable and easy release of the locking engagement, preventing misalignment and damage to the pedicle screw, ensuring smooth vertebral manipulation without additional tools and maintaining structural integrity.

Implementation Method 1

The coupling arms (10) each have a locking structure (12) for releasably engaging/coupling with a counter-locking structure (108) of the pedicle screw (100)... the locking engagement can be released by elastic deformation of the locking structure (12) and/or the counter-locking structure (108)

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The instrument (2) has a ramp structure along which the coupling arms (10) are displaced upon distal movement of the coupling unit (6) relative to the housing (4) in a medial-lateral direction of the instrument to release the locking engagement

Methodology Applied
Scientific EffectRamp mechanism: Wedge

Data Source

PatentEP4620413A1Medical instrument for vertebral manipulation
Publication Date: 2025.09.24 AESCULAP AG
  • EP4620413A1 patent drawingFigure 1~2
  • EP4620413A1 patent drawingFigure 3~5
  • EP4620413A1 patent drawingFigure 6~7

AI summary

The present disclosure relates to a medical instrument (2) for positioning a pedicle screw (100) for vertebral manipulation, comprising a housing (4) and a coupling unit (6) received on the housing (4), which is movable in a distal-proximal direction of the instrument (2) relative to the housing (4) and has a proximal base (8) and two opposing coupling arms (10) extending distally away from the base (8), each of which has a latching structure (12) for releasably engaging a counter-latching structure of the pedicle screw (100), wherein the instrument has a ramp structure (14, 30) along which the coupling arms (10) are displaced in a medial-lateral direction of the instrument (2) upon distal movement of the coupling unit (4) to release the latching engagement.