Cranial Implant Flange Recess Joint Design

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Solution Overview

Problem

Existing bone void filling implants with multiple components face challenges in secure engagement along the joint line, often resulting in gaps and uneven loading, which can lead to motion and abrasion between components, and require additional fixation members like plates and screws, making them less effective and cosmetically undesirable.

Innovation Solution

The implementation of a flange or lap-type joint between components, which allows for misalignment flexibility and provides a gap-free interface, using an overlapping flange feature on one component that fits into a recessed step feature on another, eliminating the need for fixation plates and screws along the joint line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If butt-type or bevel-type joint designs are used to connect multiple implant components, then the components can be assembled to fill bone voids, but gaps remain between adjacent components and fixation members are required which create visible cosmetic defects and weaker areas along the joint line

Engineering Contradiction:

Improvesecure engagement between componentsVSAvoidgaps between components and visible fixation members

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The flange of one component is nested within the recessed portion of the adjacent component, creating an interlocking joint that eliminates gaps between components. The flange fits into the recessed step feature, providing secure engagement without requiring external fixation members that would be visible under the skin.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Strength

If fixation members like plates and screws are added to secure butt-type or bevel-type joints, then rigidity is provided to the assembled construct, but the fixation members are noticeable under the skin and create weaker areas along the joint line

Engineering Contradiction:

Improverigidity of assembled constructVSAvoidvisible fixation members and weaker areas

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The joint design merges the connection function directly into the component interfaces through flange and recessed portion features. This integration eliminates the need for separate fixation members, providing both strength and cosmetic acceptability by making the connection internal rather than external.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If multiple component implants are used to fill large bone voids, then the implant can be constructed from smaller components that can be implanted through smaller incisions, but uneven loading causes motion and abrasion between adjacent components

Engineering Contradiction:

Improveimplantation through smaller incisionVSAvoidmotion and abrasion between components

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The flange and recessed portion features create a curved, interlocking joint interface that distributes loading evenly across the joint line. This curved geometry prevents stress concentration and eliminates motion between components, ensuring reliable engagement while maintaining the benefit of smaller implantable components.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Adaptability or versatility

If biscuit-type joint is used to affix adjacent components, then a three-piece joint configuration is achieved, but secondary operations are required to fabricate and the components are difficult to intraoperatively align and assemble

Engineering Contradiction:

Improvethree-piece joint configurationVSAvoidsecondary operations and intraoperative alignment

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The flange and recessed portion features are pre-formed during the molding process, eliminating the need for secondary fabrication operations. The complementary geometries are built into the components beforehand, allowing for easy intraoperative alignment and assembly without requiring additional manufacturing steps or complex alignment procedures.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10149762B2Multiple component bone void filling implant

Publication Date: 2018.12.11 HOWMEDICA OSTEONICS CORP

AI summary

Disclosed herein are implants and methods for filling voids in a cranium of a patient. A craniofacial implant that may be used for filling such voids may include at least first and second components each having outer and inner surfaces, the outer and inner surfaces being curved in an inferior to posterior direction and a medial to lateral direction. The first component includes a flange extending outwardly from a medial side surface thereof and the second component includes a recessed portion extending inwardly from a medial side surface thereof. The first and second components are preferably engageable to one another such that the medial side surfaces of the first and second components are adjacent one another and the flange of the first component is housed within the recessed portion of the second component.