Variable-Diameter Tissue Expander for Low-Trauma Brain Access

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Solution Overview

Problem

Current tissue expanders used in neurosurgery have a constant diameter, causing significant damage to brain tissue due to large outer diameter and friction during insertion, leading to compression and scratches.

Innovation Solution

A variable diameter tissue expansion device with an operating frame, pushing block, support rods, and an expansion tube, allowing for adjustable expansion and contraction to minimize tissue damage by reducing friction and compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a constant diameter tissue expander with large outer diameter is used, then the structural strength and stability are improved, but the compression and friction damage to brain tissue during insertion increases

Engineering Contradiction:
Improvestructural strengthVSAvoidbrain tissue damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The tissue expander employs a dynamic structure where the support rod can transition between a first state (expanded diameter for strength) and a second state (contracted diameter for insertion). The pushing block drives the support rod to change its state, allowing the device to adapt its diameter dynamically - large during insertion to provide strength, and small during tissue passage to minimize damage.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If a constant diameter tissue expander is used, then the manufacturing simplicity is maintained, but the friction and compression on brain tissue during insertion increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfriction and compression on brain tissue
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The tissue expander is divided into functional segments: the pushing block, the support rod with first and second sliding parts, and the expansion part. This segmentation allows each component to perform a specific function - the sliding parts move independently to enable diameter change, while the expansion part provides the mechanical advantage for transformation. The segmented design maintains manufacturing feasibility while enabling the variable diameter capability that reduces tissue friction and compression.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the tissue expander diameter is increased for structural stability, then the device strength is improved, but the insertion trauma to brain tissue increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidinsertion trauma
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The device achieves structural stability when needed (first state with large diameter) and minimizes insertion trauma when needed (second state with small diameter) through dynamic state transformation. The support rod's ability to switch between expanded and contracted configurations, driven by the pushing block mechanism, allows the device to provide structural reliability during insertion and operational phases while reducing trauma during the critical tissue passage phase.

Inventive Principle:
Principle #15Dynamics

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

The device reduces brain tissue damage by inserting with a small diameter and expanding uniformly, minimizing axial friction and compression, providing safer and more reliable surgical access.

Implementation Method 1

an elastic body, which is installed on the operating frame and located between the operating frame and the pushing block; one end of the elastic body is in contact with the operating frame, and another end is in contact with the pushing block, used to provide reset thrust for the pushing block

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the angle between the expansion part and the first sliding part is a right angle, and the angle between the expansion part and the second sliding part is an obtuse angle, so that the diameter of the expansion tube can be expanded during sliding

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP4635431A1Variable-diameter tissue expansion device
Publication Date: 2025.10.22 BEIJING TAIJIEWEIYE TECH CO LTD
  • EP4635431A1 patent drawingFigure 1
  • EP4635431A1 patent drawingFigure 2
  • EP4635431A1 patent drawingFigure 3~4

AI summary

The present invention belongs to the field of surgical equipment technology, and specifically relates to a variable diameter tissue expansion device, which includes an operating frame, a pushing block, support rods and an expansion tube; both the operating frame and the pushing block are provided with a central cavity. A plurality of the support rods are distributed in a circular array around the cavity on the operating frame, the support rods comprise the first sliding part, the second sliding part and an expansion part, and the first sliding part is in the sliding fit with the operating frame, the second sliding part is in the sliding fit with the pushing block, and the pushing block is in the sliding fit with the operating frame; a plurality of expansion parts are supported on the inner wall of the expansion tube, the angle between the expansion part and the first sliding part is a right angle, and the angle between the expansion part and the second sliding part is an obtuse angle, so that the diameter of the expansion tube can be expanded during sliding. When the expansion tube enters the brain tissue, it is in a contracted state and causes little damage to the brain tissue; when the expansion tube expands, it squeezes the brain tissue more evenly, slowly, and without friction, which can better protect the brain tissue.