Bone Screw Insertion Tool with Preloaded Washer

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Solution Overview

Problem

Current bone fragment reduction and fixation techniques face challenges in limited surgical space, requiring separate devices for holding fragments and guiding drill insertion, which complicates the procedure and can be difficult for single surgeons to manage, especially in small or soft bone areas.

Innovation Solution

A combined bone screw insertion system that integrates a reduction pusher and drill guide with a preloaded washer, allowing for simultaneous bone screw insertion and fracture stabilization through a single instrument, enabling the use of a pivotable footplate for varied angle application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate devices are used for holding bone fragments and guiding drill insertion, then each device can be optimized for its specific function, but the surgical space becomes insufficient and the procedure becomes more complex

Engineering Contradiction:
Improvefunctional optimizationVSAvoidnumber of devices
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the reduction pusher and drill guide into a single integrated instrument. The pusher shaft includes a longitudinal bore that receives the drill, allowing both fracture reduction and screw insertion guidance to be performed with one device. This merging eliminates the need for separate devices while maintaining both functions, directly resolving the contradiction between functional optimization and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated instrument serves multiple functions: it acts as both a reduction pusher for holding and compressing bone fragments and as a drill guide for inserting screws. The pusher shaft with its longitudinal bore provides both mechanical support for fracture reduction and guidance for drill insertion, making the device universal and multi-functional.

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

2Ease of operation

If one hand holds the pusher and another hand operates the drill, then each function can be performed with proper control, but no free hand remains to manipulate the drill guide

Engineering Contradiction:
Improvehand controlVSAvoidcoordination requirement
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

By merging the pusher and drill guide into one instrument, the patent allows the surgeon to control both functions with a single hand. The pusher shaft with its longitudinal bore enables the drill to be received and guided while the surgeon maintains control of the entire assembly, eliminating the need for a second hand to manipulate a separate drill guide.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a washer is not preloaded, then the screw can be inserted directly, but the washer may be lost and soft bone cannot support the screw head properly

Engineering Contradiction:
Improvefixation stabilityVSAvoidwasher retention mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by preloading the washer onto the pusher shaft before screw insertion. The washer is positioned in advance within the instrument, secured by spring elements, ensuring it is ready for immediate use when the screw is inserted. This prevents washer loss and ensures proper support for soft bone.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring elements automatically engage and retain the washer on the pusher shaft without requiring additional manual intervention. The washer is self-retained by the spring mechanism, eliminating the need for separate washer retention actions and ensuring the washer remains in place throughout the procedure.

Inventive Principle:
Principle #25Self-service

4Area of stationary object

If the surgical field space is limited, then the procedure becomes more confined, but multiple separate devices cannot be accommodated next to each other

Engineering Contradiction:
Improvesurgical window spaceVSAvoidnumber of devices
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the reduction pusher and drill guide into a single integrated instrument with a compact design. The pusher shaft with its longitudinal bore allows the drill to be received within the same device, significantly reducing the space required in the surgical field compared to having separate pusher and drill guide devices positioned next to each other.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2700372B1Bone screw and washer insertion tool
Publication Date: 2020.07.08 STRYKER EUROPEAN HOLDINGS I LLC
  • EP2700372B1 patent drawingFigure 1~2
  • EP2700372B1 patent drawingFigure 3
  • EP2700372B1 patent drawingFigure 4A~4B

AI summary

The insertion tool and pusher system of the present invention includes a bone screw having a head and a shaft. An annular washer is adapted to be mounted on the bone screw shaft. An insertion tool having a longitudinally extending shaft with an axial bore therethrough is provided for receiving the bone screw. The shaft has a first end with a washer retention surface surrounding the insertion tool cannulated shaft bore. The washer is held on the retention surface which positions the washer to receive the bone screw shaft. Pin-like spring elements are used to hold the washer in position. A plate is mounted on an outer surface at the first end of the inserter shaft, the plate having a bone contacting surface.