Removable Extension for Low Profile Spinal Bone Anchor

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Solution Overview

Problem

Conventional methods for stabilizing bone structures often require invasive procedures, causing tissue trauma, scarring, and prolonged recovery due to the need to cut and reposition skin and tissue, which is undesirable in minimally invasive surgical techniques.

Innovation Solution

A system featuring anchor assemblies with a bone anchor and receiver that allow a connecting member to be positioned and secured minimally invasively, with elongated extensions that are removable post-implantation, enabling the connecting member to be inserted from outside the body without invasive access, thus minimizing tissue disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional stabilization devices are used, then bone structures can be stabilized, but tissue trauma and scarring increase due to invasive procedures

Engineering Contradiction:
Improvetissue traumaVSAvoidaccess to stabilization site
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The stabilization device is divided into separate components: a percutaneous anchor inserted through a small incision, and an extension member that connects to the anchor. This segmentation allows the main body to be implanted minimally invasively while the extension provides access for connecting members, resolving the contradiction between minimal tissue trauma and ease of operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The extension member acts as an intermediary between the percutaneous anchor and the connecting member. It extends from the anchor to the skin surface, providing a pathway for the connecting member to reach the anchor without requiring large incisions or extensive tissue dissection, thus maintaining minimal tissue trauma while ensuring operational access.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If extensions are added to enable minimally invasive insertion, then tissue trauma is reduced, but device complexity increases

Engineering Contradiction:
Improvetissue traumaVSAvoidanchor assembly structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The extension member is designed as a separate, removable component that can be attached to and removed from the percutaneous anchor. This extraction approach allows the extension to be added only when needed for minimally invasive insertion, and then removed to simplify the final implant structure, reducing overall device complexity while maintaining the benefit of reduced tissue trauma.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The extension member serves a temporary function during insertion and is then discarded (removed) from the final implant configuration. This allows the device to have high complexity during the insertion phase to enable minimally invasive access, but returns to a simpler state in the final implanted form, resolving the contradiction between tissue trauma reduction and device complexity.

Inventive Principle:
Principle #34Discarding and recovering

3Shape

If the anchor assembly maintains a low profile post-implantation, then patient comfort is improved, but access for inserting connecting members becomes more difficult

Engineering Contradiction:
Improveprofile of anchor assemblyVSAvoidaccess for connecting member insertion
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The anchor assembly transitions from a high-profile configuration during insertion (with the extension member attached) to a low-profile configuration after insertion (with the extension removed). This dynamic change allows the device to provide easy access for connecting member insertion during the procedural phase while maintaining patient comfort and a low profile in the final implanted state, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2632355B1Low profile extension attachments for bone anchors
Publication Date: 2015.06.03 WARSAW ORTHOPEDIC INC
  • EP2632355B1 patent drawingFigure 1
  • EP2632355B1 patent drawingFigure 2
  • EP2632355B1 patent drawingFigure 3

AI summary

Systems and methods for positioning a connecting member adjacent the spinal column include at least one anchor assembly having an anchor engageable to bony structure and a receiver for receiving the connecting member. An elongated extension is removably engaged to the receiver and extends proximally from the receiver. The extension and at least a portion of the receiver is removable from the remaining portion of the receiver of the bone anchor after the connecting member is positioned in the receiver to provide a low profile anchor and connecting member assembly when finally implanted in the patient.