Oscillating Surgical Cutter Drive With Rack-and-Pinion Reciprocation

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Solution Overview

Problem

Existing surgical tools with rotary cutters face issues when encountering fibrous tissues like muscle and nerves, as they can wrap around the cutter and get damaged, and the mechanisms for oscillating rotary tools do not operate smoothly due to inefficient drive systems.

Innovation Solution

A surgical tool with a drive transmission system that combines a first driver for rotary oscillation and a second driver for simultaneous longitudinal reciprocation, utilizing a rack and pinion gear arrangement to achieve smooth operation and minimize damage to fibrous tissues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a rotary cutter is used to cut tissue, then cutting efficiency is improved, but fibrous tissue can wrap around the cutter and get damaged

Engineering Contradiction:

Improvecutting efficiencyVSAvoiddamage to fibrous tissue

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The rotary cutter is modified to perform oscillating motion in addition to rotation, creating a periodic reciprocating action that prevents fibrous tissue from wrapping around the cutter. The cutter oscillates between forward and reverse directions, continuously disrupting any attempting-to-wrap tissue and eliminating the harmful wrapping effect while maintaining high cutting efficiency.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The cutter transitions from simple rotary motion to a dynamic combination of rotary and oscillating motions. The drive transmission system incorporates mechanisms that dynamically adjust the cutter's motion pattern, enabling it to switch between rotational cutting and reciprocating oscillation, thereby adapting to different tissue types and preventing tissue damage.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If oscillating rotary tools are used to prevent tissue wrapping, then tissue damage is reduced, but the mechanisms do not operate smoothly

Engineering Contradiction:

Improvedamage to fibrous tissueVSAvoidsmooth operation

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

A drive transmission system with intermediary components is introduced between the motor and the cutter. This transmission system includes gears, shafts, and coupling mechanisms that smoothly transmit power while generating the oscillating motion. The intermediary components act as mediators that convert simple rotary motor output into complex oscillating cutter motion, ensuring smooth operation throughout the mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical coupling with a more sophisticated drive transmission system that uses gear mechanisms and universal joints. These mechanical substitutions allow for smoother power transmission and more controlled oscillating motion, eliminating the operational roughness associated with simpler oscillation mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If high cutting speeds are used for efficiency, then productivity is improved, but vibration increases and precision placement is compromised

Engineering Contradiction:

Improvecutting speedVSAvoidprecision placement

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The oscillating motion creates periodic engagement and disengagement of the cutter with the tissue, reducing continuous vibration at high speeds. The reciprocating action allows brief pause periods between cutting strokes, enabling precision placement and reducing cumulative vibration effects while maintaining high overall cutting productivity.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent utilizes controlled mechanical vibration through the oscillating motion to reduce unwanted vibrations. The deliberate oscillation at specific frequencies counteracts harmful vibrations, allowing high cutting speeds to be maintained without compromising precision placement or causing excessive vibration.

Inventive Principle:

Principle #18Mechanical vibration

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 tool provides efficient and precise cutting of hard tissues like bone and cartilage while reducing the risk of damaging fibrous tissues by ensuring smooth operation and minimal vibration.

Implementation Method 1

utilizing a rack and pinion gear arrangement to achieve smooth operation and minimize damage to fibrous tissues

Methodology Applied

Scientific EffectRack and pinion mechanism: Rack and Pinion

Data Source

PatentUS20250352234A1Rotary oscillating and reciprocating surgical tool

Publication Date: 2025.11.20 GLOBUS MEDICAL INC

AI summary

A surgical tool that has a pair of transmissions coupled to one another to effect driving of a cutting tool in both an oscillating manner and a reciprocating manner. The transmissions are driven by a motor coupled to one of the transmissions.