Ultrasonic Bone-Cutting Blade Structure for Deep Cortical Cuts

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Solution Overview

Problem

Existing ultrasonic surgical instruments face challenges in cutting dense cortical bone efficiently while minimizing heat generation, maintaining stiffness, and preventing bending or torsional movements, especially when performing deep cuts.

Innovation Solution

The sonotrode design features a blade with lateral depressions, ribs, and grooves to reduce friction and enhance stiffness, along with a cooling system and specific structural elements to minimize heat and improve debris removal, allowing for deeper cuts without bending or torsional issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a thick sonotrode with sharpened edges is used to cut cortical bone, then cutting performance improves, but heat generation increases and the device becomes less suitable for deep cuts

Engineering Contradiction:

Improvecutting performanceVSAvoidheat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent employs a thin blade design with a thickness of 0.1-0.5mm instead of traditional thick sonotrodes. The thin blade is equipped with lateral ribs that provide structural support and prevent bending, enabling effective cutting of cortical bone without excessive heat generation. This resolves the contradiction by achieving cutting performance through a thin, rib-reinforced blade rather than a thick sharpened sonotrode.

Inventive Principle:

Principle #30Flexible shells and thin films

2Temperature

If the sonotrode blade is made thinner to reduce heat, then heat generation decreases, but the blade becomes less stiff and more prone to bending

Engineering Contradiction:

Improveheat generationVSAvoidblade stiffness

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent applies local reinforcement by adding lateral ribs to specific regions of the thin blade. The ribs are positioned at critical locations where bending stress occurs, providing localized structural support without increasing the overall blade thickness. This enables the blade to remain thin for reduced heat generation while maintaining sufficient stiffness through strategically placed reinforcing elements.

Inventive Principle:

Principle #3Local quality

3Length of moving object

If a long sonotrode is used to enable deeper bone cuts, then cutting depth increases, but bending movements and oscillations out of plane increase

Engineering Contradiction:

Improvecutting depthVSAvoidblade stability

Core Design Contradiction:

Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent segments the blade structure by incorporating multiple lateral ribs that divide the blade into structurally supported sections. These ribs act as internal supports that prevent the long blade from bending or oscillating out of plane during deep cutting operations. The segmented reinforcement allows the sonotrode to achieve greater cutting depth while maintaining stability throughout the blade length.

Inventive Principle:

Principle #1Segmentation

4Force

If a cranked cutting device is used to achieve high amplitude in transverse direction, then cutting capability improves, but pressure sensitivity increases and stiffness in working direction decreases

Engineering Contradiction:

ImproveamplitudeVSAvoidstiffness in working direction

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

The patent employs an asymmetric blade design with lateral ribs positioned to provide differential support. The ribs are configured to allow transverse oscillation amplitude for effective cutting while maintaining stiffness in the forward working direction. This asymmetric reinforcement pattern resolves the contradiction by permitting necessary movement in one direction while preventing deformation in the working direction.

Inventive Principle:

Principle #4Asymmetry

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 improved sonotrode achieves efficient cutting of cortical bone with reduced heat generation, enhanced debris removal, and minimized bending or torsional movements, optimizing cutting performance and precision.

Implementation Method 1

ultrasonic instruments are particularly efficient. These instruments include a cutting head that for the process is pressed against the bone tissue and is set into ultrasonic oscillation. The cutting process by these instruments is basically based on a local smashing of bone tissue.

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

Transport of debris away from the cutting location as well as cooling are major issues.

Methodology Applied

Scientific EffectCooling: Cooling

Data Source

PatentUS12616483B2Device and method for perforating a dense bone layer

Publication Date: 2026.05.05 BOSONIC AG

AI summary

A device for cutting bone tissue and, more particularly, a sonotrode suitable for use with an ultrasonic surgical instrument. The sonotrode has a head and a distal end piece, the distal end piece being equipped as a rectangular blade for cutting bones using mechanical vibration. The sonotrode has at least one structural element and the structural element is selected from the group including: a support structure, a lateral depression on each side, an increased width of the blade together with a slit at the distal end of the blade, or at least one lateral rib.