Multipoint Bone Anchor Assemblies for Compromised Bone Fixation

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Solution Overview

Problem

Existing bone anchor assemblies often face issues with compromised insertion, limited flexibility in attachment points, and sub-optimal purchase with the bone, leading to potential loosening or backout, especially in compromised bone conditions.

Innovation Solution

The introduction of bone anchor assemblies with auxiliary features such as a bracket or wing, a plate, or a hook that extend from the receiver member to enhance fixation, allowing for improved anchoring and flexibility in attaching to bone surfaces, even in compromised conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional single bone anchor assembly is used, then the device structure is simple, but the fixation reliability is insufficient in compromised bone conditions

Engineering Contradiction:

Improvefixation reliabilityVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bone anchor assembly is divided into multiple independent bone engagement points (primary and auxiliary anchors) that can engage different bone structures. The auxiliary bone anchors provide additional fixation points that work independently alongside the primary anchor, increasing overall fixation reliability without requiring complete redesign of the entire assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary bone anchors are integrated within or alongside the primary bone anchor structure, with the receiver member serving as a common mounting platform. This nested configuration allows multiple fixation functions to be achieved within a compact overall structure, improving reliability while limiting the increase in device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Strength

If the bone anchor assembly is inserted in a compromised state (e.g., stripped bone opening, incorrect placement), then insertion speed is maintained, but the fixation strength becomes sub-optimal

Engineering Contradiction:

Improvefixation strengthVSAvoidinsertion precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The auxiliary bone anchors serve as pre-prepared backup fixation points that can be activated if the primary anchor insertion is compromised. The receiver member is designed beforehand to accommodate multiple anchors, so if insertion precision is insufficient for optimal primary anchor placement, the auxiliary anchors provide compensatory fixation strength.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system allows changing the number and configuration of active bone anchors based on insertion outcomes. If the primary anchor insertion is sub-optimal, the parameters of the fixation system are adjusted by activating additional auxiliary anchors, thereby maintaining adequate fixation strength despite reduced insertion precision.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the bone anchor assembly is removed and re-inserted with a larger anchor to improve fixation, then fixation strength may be improved, but the surgical time increases

Engineering Contradiction:

Improvefixation strengthVSAvoidsurgical time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The receiver member is pre-configured with multiple bone anchor openings and the capability to accommodate auxiliary anchors before insertion. This preliminary preparation eliminates the need for surgical removal and re-insertion of larger anchors, as the system is already designed to provide enhanced fixation from the outset. All necessary components are in place to activate additional fixation points without extending surgical time.

Inventive Principle:

Principle #10Preliminary action

4Adaptability or versatility

If traditional bone anchor geometry is used, then the device structure is simple, but the flexibility in locating attachment points is limited

Engineering Contradiction:

Improveflexibility in attachment pointsVSAvoidanchor geometry

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The receiver member is designed as a universal platform that can accommodate multiple types of bone anchors (primary and auxiliary) at different positions and orientations. This multi-functional design allows the same receiver member structure to provide various attachment point configurations, increasing flexibility without requiring multiple specialized geometries for different anchor types.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12376888B2Multipoint fixation implants

Publication Date: 2025.08.05 MEDOS INT SARL

AI summary

Bone anchor assemblies are disclosed herein that can provide for improved fixation as compared with traditional bone anchor assemblies. An exemplary assembly can include a bracket or wing that extends down from the receiver member and accommodates one or more auxiliary bone anchors that augment the fixation of the assembly's primary bone anchor. Another exemplary assembly can include a plate that is seated between the receiver member and the rod and accommodates one or more auxiliary bone anchors that augment the fixation of the assembly's primary bone anchor. Another exemplary assembly can include a hook that extends out from the receiver member to hook onto an anatomical structure or another implant to augment the fixation of the assembly's primary bone anchor. Surgical methods using the bone anchor assemblies described herein are also disclosed.