Intervertebral Prosthesis Endplate with Anterior Bone Ingrowth and Posterior Smooth Surface

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Solution Overview

Problem

Current intervertebral disc prostheses face challenges in achieving secure fixation and ease of implantation due to complex mechanical and physiological requirements, and the need for varied designs to accommodate individual patient variations and disorders, with existing endplates being difficult to implant and requiring high surgical skill.

Innovation Solution

The intervertebral disc prosthesis features an endplate with a plate member having an elevated region with a porous coating for bone ingrowth on the anterior portion and a smooth posterior region for easy implantation, along with optional fins for enhanced fixation and stability, allowing for secure placement and resistance to post-operative movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hard endplate is used to contact the vertebra and transfer spinal loads, then the prosthesis fixation and load transfer are improved, but the ease of implantation deteriorates due to complex surgical procedures and high skill demands

Engineering Contradiction:

Improveprosthesis fixationVSAvoidease of implantation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The endplate is segmented into distinct functional regions: a smooth posterior region for easy insertion through the surgical approach, and an anterior region with bone ingrowth promoting structures for secure fixation. This segmentation allows each region to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the endplate have different surface qualities: the posterior region has a smooth surface for ease of implantation, while the anterior region has a porous or textured surface to promote bone ingrowth. This local differentiation resolves the contradiction between ease of implantation and secure fixation.

Inventive Principle:

Principle #3Local quality

2Reliability

If a porous coating is provided on the entire endplate surface, then bone ingrowth and fixation are improved, but the ease of implantation deteriorates due to increased friction and insertion difficulty

Engineering Contradiction:

Improvebone ingrowthVSAvoidease of implantation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The porous coating is applied selectively only to the anterior portion of the endplate where bone ingrowth is needed, while the posterior portion remains smooth to facilitate easy insertion. This localized application resolves the contradiction between promoting bone ingrowth and maintaining ease of implantation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The endplate surface is segmented into two distinct zones: an anterior zone with porous structures for bone ingrowth and a posterior zone with smooth surface for easy insertion. This segmentation allows each zone to perform its specific function optimally.

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If fins are provided to engage adjacent vertebral bodies for improved fixation, then the prosthesis stability is improved, but the device complexity increases

Engineering Contradiction:

Improveprosthesis stabilityVSAvoidendplate structure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Instead of providing fins across the entire endplate surface, the invention uses a partial fin structure located at the anterior portion. This partial action provides sufficient stability through engagement with the vertebral body while avoiding the complexity of a complete fin structure.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The fin structure is localized to the anterior region where it provides maximum stability benefit, rather than being distributed across the entire endplate. This localized approach achieves the necessary stability with reduced structural complexity.

Inventive Principle:

Principle #3Local quality

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 endplate design facilitates secure fixation and easy implantation, providing stability equivalent to full anterior-posterior fins while allowing for easier insertion and reduced surgical complexity, accommodating various patient anatomies and disorders.

Implementation Method 1

a coating to promote bone ingrowth being provided on the anterior portion, but not on the posterior portion, of the elevated region

Methodology Applied

Scientific EffectBone ingrowth:

Data Source

PatentUS8470045B2Endplate for an intervertebral prosthesis and prosthesis incorporating the same

Publication Date: 2013.06.25 VB SPINE LLC

AI summary

An endplate for an intervertebral disc prosthesis includes: a plate member having a generally planar rim for contacting the peripheral cortical rim of a vertebral body, and an elevated region within the rim having an anterior region and a posterior region, wherein the anterior region of the elevated region is preferably recessed with respect to the posterior region and is treated to promote bone ingrowth. The endplate may be provided with a medial fin extending partway from the anterior edge of the endplate toward the posterior edge of the endplate.