Surgical Saw Blade Geometry for Alignment and Resonance Control

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Solution Overview

Problem

Existing surgical saw blades with angular oscillation often cause excessive trauma due to wide cutting motion, and there is a need for improved designs that minimize patient trauma while ensuring correct positioning and optimal resonant frequency.

Innovation Solution

A surgical saw blade design featuring a narrower first end, elongated shank with strategically positioned holes and stopping surfaces for engagement with the oscillating head, along with alignment holes and slots for dust management, to ensure correct positioning and prevent resonance during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an elongated saw blade with angular oscillation is used, then wide cutting motion is achieved, but patient trauma increases

Engineering Contradiction:
Improvecutting motionVSAvoidpatient trauma
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the oscillation parameter from angular to lateral, which fundamentally alters the cutting motion characteristics. This parameter change allows the blade to move side-to-side rather than angularly, reducing the width of cutting motion while maintaining effective bone cutting capability, thereby reducing patient trauma

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the first end of the saw blade is narrower than the elongated shank, then correct positioning relative to the oscillating head is ensured, but device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidblade structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The saw blade employs asymmetric geometry where the first end is narrower than the elongated shank. This asymmetric design creates a unique fit within the oscillating head, ensuring correct positioning through geometric constraints rather than requiring additional positioning mechanisms, thus achieving precise positioning without proportionally increasing complexity

Inventive Principle:
Principle #4Asymmetry

3Reliability

If holes are added to the elongated shank, then resonant frequency is optimized, but manufacturing complexity increases

Engineering Contradiction:
Improveresonant frequency controlVSAvoidblade manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the shank structure by introducing holes that change the mass distribution and stiffness characteristics of the blade. This parameter change directly affects the resonant frequency, allowing optimization to match the oscillating head's frequency and prevent resonance. The holes are strategically positioned and sized to achieve the desired frequency characteristics

Inventive Principle:
Principle #35Parameter changes

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 design minimizes patient trauma by optimizing cutting motion and preventing resonance, ensuring precise alignment and efficient dust removal, thereby enhancing surgical precision and safety.

Implementation Method 1

The hole in the shank is configured to optimize a resonant frequency of the saw blade. The hole in the shank may be configured to ensure that a resonant frequency of the saw blade is greater than an oscillation frequency of the oscillating head of the powered saw

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4044937B1Surgical saw blade
Publication Date: 2025.08.20 DEPUY SYNTHES PROD INC
  • EP4044937B1 patent drawingFigure 1~1B
  • EP4044937B1 patent drawingFigure 2~3
  • EP4044937B1 patent drawingFigure 4~8

AI summary

A surgical saw blade has an upper surface and a lower surface, and includes a first end having right and left side edges, where the first end is configured to connect to an oscillating head of a powered saw. The saw blade also has a cutting end; and an elongated shank connecting the first end and the cutting end. The first end of the saw blade may be narrower than the shank, and a stopping surface may connect the first end to the elongated shank. The stopping surface is configured to engage the oscillating head of the powered saw, so as to ensure correct positioning of the saw blade relative to the oscillating head. The elongated shank of the saw blade may have an elongated hole through the shank, where the size and shape of the elongated hole are configured to optimize a resonant frequency and/or a dynamic stiffness of the saw blade. The cutting end of the saw blade may have a plurality of first teeth thereon, where each first tooth is mounted on a distal end of a tine. Each pair of adjacent tines is separated by a longitudinal slot, with a distal end of each longitudinal slot being bridged by a web connecting a corresponding pair of adjacent tines.