Spinal Fixation Device Cam Mechanism Reduces Insertion Effort

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The insertion of pedicle screws into vertebrae during spinal surgery is a time-consuming and labor-intensive process due to the need for multiple rotations, which can be inefficient and laborious, especially when securing fixation devices to osseous tissue.

Innovation Solution

A fixation device comprising an outer member with a central bore and slot, an inner member with a cam shaft body, and retaining members that move laterally upon rotation, allowing for minimal rotational effort to secure the device into osseous tissue by cutting or threading into the tissue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional pedicle screws are used for fixation, then securement to osseous tissue is achieved, but the insertion process becomes time-consuming and labor-intensive due to multiple rotations required

Engineering Contradiction:

Improvesecurement to osseous tissueVSAvoidinsertion time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The fixation device is divided into separate components: an outer member with a slot, an inner member with a cam shaft body, and a retaining member. This segmentation allows the retaining member to be deployed independently through the slot using minimal rotation of the inner member, reducing insertion time while maintaining securement reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The retaining member transitions from a retracted state within the outer member to a deployed state extending through the slot via cam mechanism. This dynamic deployment allows the retaining member to engage with osseous tissue with minimal rotational effort, significantly reducing insertion time compared to traditional screws requiring multiple rotations.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If multiple rotations are applied during insertion, then the fixation device is fully inserted into vertebrae, but the procedure becomes laborious and time-consuming

Engineering Contradiction:

Improveinsertion depthVSAvoidrotational effort

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The cam shaft body acts as an intermediary mechanism between the inner member and the retaining member. Rotation of the inner member transforms rotational motion into linear deployment motion of the retaining member through the cam mechanism, achieving precise insertion depth control with minimal rotational effort.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional threaded screw mechanism requiring multiple rotations is replaced with a cam-based deployment system. The cam shaft body converts minimal rotation into effective deployment of the retaining member through the slot, reducing rotational effort while maintaining precise insertion depth control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If retaining members are deployed through slots, then fixation is achieved with minimal rotational effort, but the device structure becomes more complex

Engineering Contradiction:

Improverotational effortVSAvoidcomponent structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The retaining member is nested within the outer member during insertion, with the inner member containing the cam shaft body that controls the retaining member's deployment. This nested arrangement allows complex functionality to be achieved within a compact structure, minimizing the increase in device complexity while enabling easy operation with minimal rotational effort.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 fixation device reduces the rotational effort required for insertion, enabling faster and more efficient securement into osseous tissue compared to traditional bone screws, facilitating quicker surgical procedures.

Implementation Method 1

The inner member includes a cam shaft body disposed within the central bore of the outer member. The cam shaft body is coupled to the retaining member such that rotation of the inner member moves the retaining member between the initial and deployed positions.

Methodology Applied

Scientific EffectCam mechanism: Cam

Data Source

PatentUS10806494B2Fixation devices, fixation systems, and methods of using the same

Publication Date: 2020.10.20 VB SPINE LLC

AI summary

A fixation device includes an outer member, a retaining member, and an inner member. The outer member includes an elongated body portion defining a central bore through at least a portion thereof that extends along a central longitudinal axis. The elongated body portion includes a slot defined therethrough. The retaining member is disposed within the outer member when in an initial position and extends through the slot of the outer member when in a deployed position. The inner member includes a cam shaft body disposed within the central bore of the outer member. The cam shaft body is coupled to the retaining member such that rotation of the inner member moves the retaining member between the initial and deployed positions.