Reciprocating Surgical Instrument Motion Conversion Mechanism

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Solution Overview

Problem

Current surgical tissue removal devices with rotational cutting surfaces face challenges in precision and control, especially in confined spaces, due to moment forces and the risk of damaging adjacent soft tissues, making it difficult to create flat surfaces and remove targeted tissues effectively.

Innovation Solution

A tissue removal system that converts rotary motion into reciprocal motion using a motion conversion mechanism with a rotatable member, cam members, and a spherical bearing, allowing the cutting head to translate between retracted and extended positions, coupled with suction for efficient debris removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotational cutting surface is used, then tissue removal capability is provided, but control precision and ability to create flat surfaces deteriorate due to moment forces

Engineering Contradiction:
Improvecontrol precisionVSAvoidflat surface creation
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional rotary cutting motion into a reciprocating linear motion. The cutting head moves back and forth in a straight line rather than rotating, which eliminates the moment forces that cause control difficulties and enables precise flat surface creation while maintaining effective tissue removal capability

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If a rotational cutting surface is used, then tissue removal is achieved, but precision in confined spaces deteriorates due to moment forces pivoting on the hand

Engineering Contradiction:
Improvetissue removal efficiencyVSAvoidcontrol precision in confined spaces
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

By converting rotary motion to reciprocating linear motion, the invention eliminates the pivoting moment forces that occur with rotary instruments in confined spaces. The linear reciprocating cutting head provides stable, predictable forces that are easier to control precisely when working in tight anatomical areas

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If a rotational cutting surface is used, then cutting action is provided, but safety deteriorates due to risk of grabbing adjacent soft tissues

Engineering Contradiction:
Improvecutting capabilityVSAvoidrisk of damaging soft tissues
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The reciprocating linear cutting motion replaces the rotary motion that tends to grab soft tissues. The linear back-and-forth movement provides controlled, directional cutting forces that are less likely to inadvertently capture or damage adjacent soft tissue structures

Inventive Principle:
Principle #13The other way round (Inversion)

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

Enhances control and precision in removing targeted tissues, reduces injury to surrounding soft tissues, and efficiently removes debris, facilitating the creation of flat surfaces in confined surgical areas.

Implementation Method 1

a motion conversion mechanism, the motion conversion mechanism comprising the rotatable member, a first cam member, a second cam member, and a spherical bearing positioned between the first and second cam members

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

a spherical bearing positioned between the first and second cam members

Methodology Applied
Scientific EffectBall bearing: Ball Bearing

Data Source

PatentEP2615988B1Reciprocating surgical instrument
Publication Date: 2014.10.29 IMDS LLC
  • EP2615988B1 patent drawingFigure 1A
  • EP2615988B1 patent drawingFigure 1B~1C
  • EP2615988B1 patent drawingFigure 2

AI summary

A surgical rasping system functional in multiple orthopedic applications, including but not limited to shoulder, knee, hip, wrist, ankle, spinal, or other joint procedures. The system may comprise a tissue removal member (502) with a rasping head (508) which may be low profile and offer a flat cutting/rasping surface, or with a cutting head with at least one cutting edge. The tissue removal member is configured to be driven by an attached hub that translates a rotational movement into a reciprocating motion. Suction for removal of bone fragments or other tissues is provided through an opening spaced apart from or adjacent to the rasping surface. A radiofrequency ablation (RF) electrode may be carried on the rasping system to provide ablation or coagulation of soft tissues.