Modular Spinal Rod Reducer for Sequential Derotation and Screw Insertion

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Solution Overview

Problem

Traditional spinal fixation procedures require multiple separate instruments for rod reduction, derotation, and set screw insertion, leading to surgeon fatigue, prolonged operating time, and increased patient risk due to frequent instrument switching.

Innovation Solution

A modular surgical instrument comprising an outer sleeve and inner sleeve with threaded and translating members, along with a derotation instrument, that allows for integrated rod reduction, derotation, and set screw insertion, reducing the need for multiple instruments and simplifying the workflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiple separate instruments are used for rod reduction, derotation, and set screw insertion, then each specific function can be performed with a dedicated tool, but the number of instruments increases, operating time is prolonged, and surgeon fatigue increases

Engineering Contradiction:
Improvededicated tool functionVSAvoidnumber of instruments
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple separate surgical instruments (rod reduction instrument, derotation instrument, and set screw insertion instrument) into a single integrated instrument. The instrument body houses an inner sleeve that can perform rod reduction, while the instrument also accommodates a derotation sleeve and set screw driver through working channels, allowing all three functions to be performed with one tool rather than multiple separate instruments

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated instrument is designed with multi-functionality to perform rod reduction, derotation, and set screw insertion within a single device. The instrument body contains an inner sleeve with a rod reduction member, working channels for derotation and set screw insertion, and various engagement features that enable it to serve multiple surgical purposes, eliminating the need for multiple specialized instruments

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If multiple separate instruments are used for rod reduction, derotation, and set screw insertion, then each function can be performed with specialized equipment, but frequent instrument switching is required, increasing operating time and patient risk

Engineering Contradiction:
Improvespecialized equipmentVSAvoidoperating time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent merges rod reduction, derotation, and set screw insertion functions into a single instrument, eliminating the need for frequent instrument switching. The integrated design allows the surgeon to perform all three procedures sequentially with one instrument, significantly reducing the time lost to instrument changes and associated patient risks

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple separate instruments are used for rod reduction, derotation, and set screw insertion, then comprehensive functionality is achieved, but the number of steps and instrumentation increases, leading to surgeon fatigue and prolonged procedure time

Engineering Contradiction:
Improvecomprehensive functionalityVSAvoidworkflow simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent combines comprehensive surgical functionality (rod reduction, derotation, set screw insertion) into a single instrument with a unified design. The instrument body integrates an inner sleeve for rod reduction, working channels for derotation and set screw insertion, and modular components that maintain specialized functionality while simplifying the overall workflow by reducing the number of instruments the surgeon must handle

Inventive Principle:
Principle #5Merging (Combining)

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 modular instrument streamlines spinal fixation procedures by minimizing the number of steps and instruments required, enhancing efficiency and reducing surgeon fatigue and patient risk.

Implementation Method 1

The inner sleeve can include a threaded member and a translating member that contacts the rod to drive the rod distally into the bone anchor assembly

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP4301258B1Sequential reducer
Publication Date: 2025.11.26 MEDOS INT SARL
  • EP4301258B1 patent drawingFigure 1~2
  • EP4301258B1 patent drawingFigure 3~4
  • EP4301258B1 patent drawingFigure 5

AI summary

Surgical instruments that are configured to couple to a bone anchor assembly to provide a modular platform for carrying out various steps of a surgical procedure, such as spinal rod reduction and derotation, are provided. For example, in one embodiment a surgical instrument can include an outer sleeve terminating in a pair of extensions, an inner sleeve having a proximal threaded portion and a distal translating portion configured to pass through the outer sleeve, and a pair of pivoting arms received in the extensions of the outer sleeve. The pivoting arms can be configured to extend into a channel of the outer sleeve to couple a bone anchor to the outer sleeve, and a proximal end portion of the outer sleeve can include one or more flats configured to engage with another instrument.