Bone Fixation Device With Melt-Anchor And Cable Tie Compression

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Solution Overview

Problem

Conventional bone screws used for fixing fractures often fail to achieve compression due to threading that pulls both bone fragments in the same direction, requiring specialized screws and increasing material usage, and can disengage from the driver, complicating procedures.

Innovation Solution

A device with a thermoplastic polymer-coated elongate body that uses L-pin technology to melt and expand, anchoring within the bone, combined with a cable tie mechanism for compression, allowing for adjustable and reusable fixation of fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If standard bone screws with threading are used to fix fractures, then the bone fragments can be held together, but the threading pulls both fragments in the same direction preventing compression

Engineering Contradiction:

Improvefracture fixation strengthVSAvoidcompression capability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The device separates the anchoring function (distal end in bone) from the compression function (cable tie mechanism at proximal end). The distal end anchors to the far bone fragment while the cable tie head compresses the near fragment, allowing independent control of fixation and compression forces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using threading to pull bone fragments together (which pulls both in the same direction), the invention uses a cable tie mechanism that wraps around the bone fragments and applies compression force in the opposite direction, achieving compression where conventional screws fail.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If specialized screws in various lengths and configurations are used to achieve compression, then compression can be achieved, but the number of materials required increases

Engineering Contradiction:

Improvecompression capabilityVSAvoidnumber of different screw types

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The single device performs multiple functions: the elongate body provides anchoring in the bone, the cable tie head provides compression, and the system works with standard bone screw threading. This multi-functional design eliminates the need for multiple specialized screw types while achieving both fixation and compression.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Strength

If bone screws are used for fixation, then bone fragments can be held together, but the screws often disengage from the driver complicating procedures

Engineering Contradiction:

Improvefracture fixation strengthVSAvoiddriver engagement reliability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The cable tie head is nested over the elongate body, creating a layered structure where the cable tie mechanism is positioned externally. This allows the driver to engage with the cable tie head's drive interface rather than the bone screw threading, preventing disengagement issues while maintaining secure fixation.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Adaptability or versatility

If a cable tie mechanism is used for compression, then adjustable and reusable fixation is achieved, but the device requires laser melting and expansion technology

Engineering Contradiction:

Improveadjustable and reusable capabilityVSAvoidlaser melting and expansion mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The distal end of the elongate body undergoes a phase transition from solid to melted state when exposed to laser energy, then re-solidifies to form an expanded anchor mass. This phase change enables permanent anchoring without complex mechanical expansion mechanisms, simplifying the overall device design while enabling reusability.

Inventive Principle:

Principle #36Phase transitions

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 effective compression of fractures by anchoring the device within the bone and allowing adjustable tension, reducing material waste and simplifying procedures by reusing components.

Implementation Method 1

a coating along an outer surface thereof, the coating adapted to absorb a selected frequency of light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

portions of the coating melt to form a mass

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

uses L-pin technology to melt and expand

Methodology Applied

Scientific EffectLaser heating: Laser

Data Source

PatentUS9480514B2Cable tie L-pin

Publication Date: 2016.11.01 DEPUY SYNTHES PROD INC

AI summary

A device for treating a bone includes (a) an elongate body sized and shaped for insertion into a bone and extending longitudinally from a proximal end to a distal end, the elongate body including a channel extending therethrough and a coating along an outer surface thereof, the coating adapted to absorb a selected frequency of light such that, when the selected frequency of light is applied thereto, portions of the coating melt to form a mass; and (b) a first anchor member slidably mountable over the elongate body and movable therealong from a first position at the proximal end of the elongate body to a second position adjacent a bone into which the elongate body has been inserted to cooperate with the mass to fix the elongate body to the bone.