Adjustable Spinal Fusion Cage for Patient-Specific Vertebral Fit

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Solution Overview

Problem

Conventional spinal fusion cages are not height-adjustable, requiring multiple product groups to accommodate varying patient anatomies, leading to increased manufacturing and inventory burdens and suboptimal surgical outcomes.

Innovation Solution

A height-adjustable spinal fusion cage with a design featuring adjustable end plates and moving blocks, allowing linear adjustment to fit the specific distance between vertebral bodies, reducing the need for multiple product variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional fixed-height spinal fusion cages are used, then manufacturing and inventory management become complex requiring multiple product groups, but the cages cannot adapt to varying patient anatomies and vertebral body distances

Engineering Contradiction:
Improveadaptability to varying patient anatomiesVSAvoidnumber of product groups
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spinal fusion cage incorporates movable blocks that can slide along the longitudinal axis between the first and second end plates, transforming the fixed-height cage into a dynamic, height-adjustable structure. This allows a single cage design to adapt to different vertebral body distances and patient anatomies without requiring multiple fixed-height product variants

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cage is segmented into a body, first end plate, second end plate, and movable blocks that can independently move relative to each other. This segmentation enables the height adjustment mechanism while maintaining structural integrity, resolving the contradiction between adaptability and device complexity

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multiple fixed-height cage product groups are manufactured, then all patient anatomies can be covered, but production costs and inventory burdens increase

Engineering Contradiction:
Improvecoverage of patient anatomiesVSAvoidproduction efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The height-adjustable cage design makes a single product group universal, capable of fitting multiple patient anatomies and vertebral body distances. This eliminates the need to produce and manage multiple fixed-height cage variants, thereby reducing production complexity and inventory burdens while maintaining broad anatomical coverage

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple fixed-height cage product groups are maintained, then anatomical coverage is complete, but surgical selection and implantation complexity increase

Engineering Contradiction:
Improveanatomical coverageVSAvoidsurgical selection simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The dynamic height-adjustment mechanism allows surgeons to optimize cage fit intraoperatively by adjusting the height to match the specific vertebral body distance, eliminating the need to pre-select from multiple fixed-height options. This simplifies surgical decision-making while maintaining anatomical coverage

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4094730B1Height-adjustable spinal fusion cage
Publication Date: 2026.02.11 L&K BIOMED CO LTD
  • EP4094730B1 patent drawingFigure 1~2
  • EP4094730B1 patent drawingFigure 3~4
  • EP4094730B1 patent drawingFigure 5~6

AI summary

The present invention relates to a spinal fusion cage which is inserted between vertebral bodies with the lowest height and is height-adjustable in the inserted state, whereby cages having heights within a predetermined range can be replaced by a single cage. Therefore, manufacturers can reduce product groups that need to be produced, and can also reduce product stock. Further, in contrast to the conventional cages having predetermined heights at regular intervals, the height of the inventive cage can be linearly adjusted according to the distance between the vertebral bodies of a patient, and thus a surgery can be performed using the cage adjusted to an optimum height according to the patient's condition.