Shape-Memory Bone Nail for Percutaneous Vertebral Fusion

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Solution Overview

Problem

Current surgical methods for vertebral fusion, such as connecting human vertebral bodies, are invasive and require large operations with significant recovery time, posing risks and limitations for patients.

Innovation Solution

A percutaneous, minimally invasive approach using a specially designed nail that can be inserted through the bone wall, changing shape to facilitate a curved path through vertebral bodies for fusion, potentially combined with expandable or self-expanding spacers for stabilization, allowing for a less invasive procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional open surgical approach is used for vertebral fusion, then reliable bone connection is achieved, but patient trauma and recovery time are significantly increased

Engineering Contradiction:
Improvebone connection reliabilityVSAvoidpatient trauma
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The surgical procedure is segmented into percutaneous insertion phase and intraosseous expansion phase. The nail is inserted through a small incision in segments (insertion tube + nail), then expanded inside the bone to achieve full stabilization effect, minimizing external trauma while ensuring reliable internal connection

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The nail system uses a nested structure where the insertion tube contains the compressed nail, which in turn may contain expandable spacers or cement. This nested configuration allows delivery of the full treatment system through a minimal access path, reducing patient trauma while maintaining connection reliability

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If percutaneous minimally invasive approach is used, then patient trauma is reduced, but insertion of curved nail through straight tube becomes technically difficult

Engineering Contradiction:
Improvepatient traumaVSAvoidnail insertion difficulty
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The nail transitions from a static compressed state during insertion to a dynamic expanded state after insertion. The nail is inserted in a compressed, space-efficient configuration, then expanded in-situ to achieve the required curved shape and stabilization function, solving the geometric constraint of straight tube insertion

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The physical parameters of the nail are changed from compressed to expanded state, and from linear to curved configuration, after insertion. This parameter transformation allows the nail to achieve its functional curved shape within the constrained geometry of percutaneous access

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If straight nail is used for percutaneous insertion, then insertion is simple, but curved path through vertebral bodies cannot be achieved

Engineering Contradiction:
Improveinsertion simplicityVSAvoidnail curvature
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The nail is designed as a dynamic structure that changes shape after insertion. It is inserted in a simple straight compressed configuration, then transforms to a curved expanded configuration to follow the anatomical path through vertebral bodies, combining insertion simplicity with functional curvature

Inventive Principle:
Principle #15Dynamics

4Reliability

If extensive open surgery is performed, then complete vertebral fusion is achieved, but operation time and rehabilitation duration are increased

Engineering Contradiction:
Improvevertebral fusion completenessVSAvoidrehabilitation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The fusion procedure is segmented into minimal access insertion and internal stabilization phases, avoiding extensive open dissection. The nail system delivers complete fusion capability through percutaneous access, reducing surgical time while maintaining fusion completeness and enabling earlier rehabilitation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The expandable nail and associated spacers or cement provide self-stabilizing function after insertion, eliminating the need for extensive external fixation or prolonged postoperative bracing. This self-service stabilization reduces rehabilitation time while ensuring complete fusion

Inventive Principle:
Principle #25Self-service

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 a minimally invasive vertebral body fusion with reduced risk and recovery time, providing stable anchoring and potential for improved patient outcomes by minimizing tissue disruption and complications.

Implementation Method 1

The internal stress can be elastic or superelastic bending stress.

Methodology Applied
Scientific EffectElastic bending stress: Elasticity

Implementation Method 2

The internal stress can be elastic or superelastic bending stress.

Methodology Applied
Scientific EffectSuperelastic bending stress: Pseudoelasticity

Implementation Method 3

The internal stress can also be temperature-dependent, in particular when using a metal with so-called shape memory.

Methodology Applied
Scientific EffectShape memory: Shape Memory Alloy

Implementation Method 4

it can be driven into a first vertebral body via a side wall of the vertebral body in a direction approximately perpendicular to the local axis of the spine (e.g. with a hammer)

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2640289B1Device for connecting bony structures
Publication Date: 2016.09.14 STRECKER ERNST PETER
  • EP2640289B1 patent drawingFigure 1~2
  • EP2640289B1 patent drawingFigure 3
  • EP2640289B1 patent drawingFigure 4~5

AI summary

The invention relates to a nail for connecting bony structures, which is designed for percutaneous insertion into at least one bone. The nail (4) is configured to assume a first shape, in which said nail can be positioned substantially straight in an insertion tube (3), and a second shape, in which said nail assumes a curved shape outside the insertion tube (3). The nail is pointed at the distal end thereof.