Expandable Spinal Implant With Plastically Deformable Links

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Solution Overview

Problem

Existing expandable spinal implants for spinal surgery lack a mechanism to efficiently expand within a disc space between vertebrae, limiting their ability to restore or enhance spinal lordosis effectively through a small surgical opening.

Innovation Solution

A plastically deformable expandable spinal implant with two plates and transverse members, where a screw causes separation of the transverse members and rotation of links, allowing the plates to expand and create an angular relationship between vertebrae, mimicking natural lordosis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional expandable spinal implant uses a wedge along a ramp or rotation of a rectangular blocker for expansion, then the implant can be expanded within the disc space, but the expansion mechanism is complex and requires a relatively large surgical opening

Engineering Contradiction:

Improvesurgical opening sizeVSAvoidexpansion mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The implant is divided into two separate plates (first plate and second plate) that can be inserted independently through small openings, with expansion achieved by separating these plates via screw advancement, simplifying the expansion mechanism while reducing surgical opening requirements

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of expanding the implant by translating a wedge along a ramp or rotating a rectangular blocker (traditional methods), this invention inverts the approach by using screw advancement to directly separate the two plates, creating a more straightforward expansion mechanism that requires smaller surgical openings

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If the implant plates are separated to expand the implant height, then spinal lordosis can be restored or enhanced, but the links must undergo plastic deformation which complicates the structural design

Engineering Contradiction:

Improveangular relationship precisionVSAvoidlink deformation mechanism

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The links are designed to undergo controlled plastic deformation as the plates separate, changing their geometric parameters from an initial configuration to a final configuration that establishes the desired angular relationship between vertebrae, achieving precise lordosis restoration through material property utilization

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The implant utilizes materials with specific plastic deformation characteristics that allow the links to permanently set at the desired angle after expansion, combining structural integrity with controlled deformability to achieve both structural strength and angular precision

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If the implant is designed to expand within a small surgical opening, then patient trauma is reduced, but the expansion force and stability required for spinal fusion are compromised

Engineering Contradiction:

Improvepatient traumaVSAvoidspinal load transfer capacity

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The two plates and expansion mechanism are designed to nest within each other in a compact configuration that can be inserted through a small surgical opening, then expand to provide sufficient surface area and structural strength for spinal load transfer and fusion stability

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The implant transitions from a compact low-profile configuration during insertion to an expanded three-dimensional structure with increased height and surface area after expansion, utilizing dimensional transformation to achieve both minimal patient trauma and adequate load-bearing capacity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Enables efficient expansion within a small surgical opening to restore or enhance spinal lordosis, providing a stable angular relationship between vertebrae for fusion and load transfer, suitable for various spinal surgical procedures.

Implementation Method 1

The first transverse member includes a threaded opening that extends therethrough. The screw includes a threaded section sized and shaped to be threaded through the opening in the first transverse member

Methodology Applied

Scientific EffectThreading: Screw

Implementation Method 2

advancing the screw through the opening in the first transverse member causes separation of the transverse members, which preferably causes plastic deformation of the links via rotation thereof, resulting in an increase in the distance between the bone contacting surfaces

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS9713536B2Expandable spinal implant and method of implanting same

Publication Date: 2017.07.25 WARSAW ORTHOPEDIC INC

AI summary

An expandable spinal implant for insertion in a disc space between two adjacent vertebrae. The expandable spinal implant is moveable from an unexpanded configuration to an expanded configuration. The expandable spinal implant includes a first plate having plastically deformable links, a second plate, two transverse members, and a screw. The screw forces apart the transverse members which causes rotational deformation of the links and separation of the plates.