Spinal Fusion Device Segmented Retention and Load Bearing

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Solution Overview

Problem

Existing spinal fusion techniques face issues with device migration and tissue damage due to the use of bone screws, and the difficulty in preparing vertebrae end plates for fusion, which can lead to discomfort and instability.

Innovation Solution

A spinal fusion device with a U-shaped load bearing component and a retention device that prevents migration, allowing access to vertebrae end plates for preparation and fusion, using fasteners like bone screws to secure the device in place and an anti-backout mechanism to prevent loosening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bone screws are used to secure the fusion device, then the device can be固定在 place, but the insertion and tightening of bone screws causes device migration

Engineering Contradiction:

Improvedevice fixationVSAvoiddevice position accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The fusion device is divided into separate functional components: a load-bearing cage portion and a retention device portion. The retention device with wings is inserted first to establish precise positioning, then the cage portion is added to provide compression. This segmentation allows the retention device to prevent migration without being disturbed by subsequent screw insertion, while the cage provides stable fixation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The retention device with positioning wings is inserted into the intervertebral space before the cage portion and before any bone screws are inserted. This preliminary action establishes the precise position of the fusion device, creating a stable framework that prevents migration during subsequent steps of screw insertion and tightening.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If fusion devices protrude from the spine to provide stability, then device stability is improved, but surrounding vascular or neurological tissues are damaged or endangered

Engineering Contradiction:

Improvespinal stabilityVSAvoidtissue damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The retention device with wings is nested within the intervertebral space between adjacent vertebrae, and the cage portion is nested within or attached to the retention device. This nested configuration ensures that the entire fusion device remains contained within the natural anatomical boundaries of the intervertebral space, preventing protrusion into surrounding neural or vascular structures while maintaining spinal stability.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The retention device features thin, flexible wings that can conform to the natural contours of the vertebral endplates and intervertebral space. These thin-profile retention elements provide stable anchoring without creating bulky protrusions that would endanger surrounding tissues, allowing the device to maintain stability while minimizing its external profile.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If surgical instruments are used to scrape end plates while holding adjacent end plates apart, then end plates can be prepared for fusion, but the procedure is difficult and not exact

Engineering Contradiction:

Improveend plate preparationVSAvoidend plate preparation accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The retention device with wings serves as an intermediary structure that is inserted into the intervertebral space and engages with the vertebral endplates. This intermediary device provides stable engagement and precise positioning, allowing surgeons to prepare endplates with greater accuracy and ease compared to traditional methods that require manual manipulation with multiple instruments.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If surgical instruments are used to scrape end plates, then end plates can be prepared for fusion, but nearby tissue may be damaged

Engineering Contradiction:

Improveend plate preparationVSAvoidnearby tissue damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The retention device acts as a protective intermediary that is inserted first and provides stable engagement with the vertebral structures. This intermediary framework protects nearby neural and vascular tissues from accidental injury during the endplate preparation process, while still allowing effective scraping and preparation of the endplates for fusion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8795373B2Interbody fusion device, integral retention device, and associated methods

Publication Date: 2014.08.05 SPINESMITH PARTNERS LP

AI summary

A method and apparatus is provided for use in spinal fusion procedures. A one or two piece interbody fusion device has a fusion bearing component designed to bear the axial loading from the end plates of adjacent vertebrae. An optional retention piece prevents migration of the load bearing device. One or more fasteners secure the retention device to the vertebrae above and below the load bearing device. The fasteners cause the end plates of the vertebrae to compress the end plates to the load bearing device to facilitate proper fusion. An anti-backout mechanism prevents the fasteners backing out.