Spreading Blade Snap-Fit Mechanism for Spinal Surgery

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Solution Overview

Problem

Existing expanding devices for spinal surgery often cause skin damage due to uneven tensile strength and direction deviations during manual expansion, and are inconvenient to replace, especially when using fixed blades connected to devices.

Innovation Solution

The design of an expanding blade with snap-fit portions, a partition panel, and hook edges allows for easy installation and replacement in both unidirectional and bidirectional expanding devices, featuring a convex ring and arched partition panel to prevent skin damage and facilitate secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual skin expansion is performed, then the incision can be opened, but the skin is easily damaged due to uneven tensile strength or direction deviation

Engineering Contradiction:
Improveease of skin expansionVSAvoidskin damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The expanding device is divided into multiple blades (first expanding blade and second expanding blade) that can be independently positioned and adjusted. Each blade has separate adjustment mechanisms allowing independent control of expansion direction and force distribution, preventing concentrated stress on single skin areas and reducing damage risk

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device incorporates adjustable blades with movable positions and angles relative to the device body. The blades can be dynamically repositioned along guide rails and rotated to different angles to match the curvature and tension distribution of the skin, enabling adaptive expansion that follows natural skin stress patterns rather than applying fixed rigid forces

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If fixed blades are connected with the device, then structural stability is improved, but replacement and use are inconvenient

Engineering Contradiction:
Improvestructural stabilityVSAvoidconvenience of blade replacement
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The blade adjustment mechanism uses a nested structure where the blade can be inserted into and removed from the device body through a dedicated slot. The blade contains internal positioning features that nest with corresponding features in the device body, providing stable connection during use while allowing easy insertion and removal when replacement is needed

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The blade connection transitions from a fixed static state to a dynamically adjustable state. Blades can be easily inserted and removed, and during operation, their positions and angles can be adjusted dynamically. This dynamic capability allows the system to maintain stability during use while enabling convenient replacement when needed

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If different expanding devices are used for unidirectional and bidirectional expansion, then functional requirements are met, but the number of instruments increases and costs rise

Engineering Contradiction:
Improvefunctional capability for different expansion typesVSAvoidnumber of instruments
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The expanding device is designed with a universal structure that can perform both unidirectional and bidirectional expansion functions. The device body contains multiple blades that can be independently adjusted and positioned. By configuring one or more blades and adjusting their positions and angles, the same device can achieve unidirectional expansion (using one blade) or bidirectional expansion (using multiple blades in coordinated positions), eliminating the need for separate specialized devices

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

Solution Approach 2:

The device is segmented into multiple independent functional modules (multiple blades, each with independent adjustment mechanisms). This segmentation allows flexible configuration where blades can be used individually for unidirectional expansion or in combination for bidirectional expansion. The modular segmented design enables one device to replace multiple specialized devices while maintaining all required functional capabilities

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3705053B1Spreading blade, unidirectional spreading device and bidirectional spreading device
Publication Date: 2024.02.28 SHANGHAI REACH MEDICAL INSTR
  • EP3705053B1 patent drawingFigure 1
  • EP3705053B1 patent drawingFigure 2
  • EP3705053B1 patent drawingFigure 3~4

AI summary

The invention provides an expanding blade, comprising a first snap-fit portion, a second snap-fit portion, a fixation portion, a partition panel and hook edges, wherein, the first snap-fit portion has an axial flat section on one side; the second snap-fit portion is connected with the first snap-fit portion at one end and fixed to the fixation portion at the other end, and a convex locating block is arranged on the side wall of the second snap-fit portion; the partition panel is connected with the fixation portion at one end, the hook edges which are inclined outwards is arranged at the other end, and both the fixation portion and the hook edges are arranged on the same side of the partition panel. In addition, the invention also puts forward a unidirectional expanding device and a bidirectional expanding device which use the expanding blade. In this application, two fastening structures, i.e. the first snap-fit portion and the second snap-fit portion, arranged for the expanding blade can be snap-fitted in with different devices using different installation methods. Both the unidirectional expanding device and the bidirectional expanding device can also use the same kind of expanding blades, which reduces the number of instruments used in operations and lowers the cost, and both of them are simply fastened with simple structures, which is convenient for disassembly, assembly and replacement.