Angled Rotary Tissue Cutting Instruments With Flexible Couplings

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing angled rotary tissue cutting instruments face limitations in accessing surgical sites due to the stretching of flexible inner members, which leads to increased costs and the need for replacement, especially when the outer member is bent beyond a certain angle, as previous designs are not robust enough to maintain torque transmission effectively.

Innovation Solution

A flexible inner tubular member with a coupling comprising inner, middle, and outer spiral members made from flat strips of stainless steel, where the widths and thicknesses of the strips are intentionally varied to enhance flexibility and resistance to stretching, allowing for effective torque transmission across a wider range of bend angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the outer member is bent to access surgical sites, then adaptability is improved, but the flexible inner member stretches and loses integrity

Engineering Contradiction:

Improveaccess to surgical sitesVSAvoidinstrument integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The flexible inner member is divided into multiple spiral segments (inner spiral, middle spiral, outer spiral) wound in opposite directions. This segmentation allows each segment to independently accommodate bending stresses, preventing the stretching and integrity loss that occurs in conventional single-structure flexible members when the outer member is bent to access surgical sites.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flexible inner member uses a composite structure combining three different spiral members made from flat stainless steel ribbons with varying dimensions. The inner and outer spirals use ribbons of one dimension while the middle spiral uses a different dimension, creating a composite structure that provides both flexibility for bending and resistance to stretching, thereby maintaining instrument integrity during surgical site access.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional spiral designs are used, then manufacturing is simple, but the spirals stretch prior to assembly requiring replacement

Engineering Contradiction:

Improveflexible transmission fabricationVSAvoidresistance to stretching

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Each spiral member is constructed from flat stainless steel ribbons with specific local dimensions optimized for its function. The inner and outer spirals use ribbons of one dimension while the middle spiral uses a different dimension, creating local quality variations that provide stretching resistance throughout the flexible transmission structure while maintaining ease of manufacture through standard ribbon forming processes.

Inventive Principle:

Principle #3Local quality

3Reliability

If the flexible inner member is made more robust to prevent stretching, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveresistance to stretchingVSAvoidflexible coupling structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flexible inner member is segmented into three distinct spiral members (inner, middle, outer) wound in opposite directions. This segmentation provides robustness against stretching through distributed structural support while maintaining manageable device complexity, as each segment can be manufactured separately using standard processes and then assembled into the complete flexible transmission.

Inventive Principle:

Principle #1Segmentation

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 solution enables the use of angled rotary tissue cutting instruments with outer members bent at angles greater than 30°, reducing the risk of stretching and maintaining instrument integrity, thus reducing costs and improving operational flexibility and robustness.

Implementation Method 1

The flexible coupling disposed within the angled length portion transmits torque to rotate the cutting element while conforming to the angled, curved or bent configuration of the outer body

Methodology Applied

Scientific EffectSpiral structure flexibility: Elasticity

Data Source

PatentUS8029524B1Angled rotary tissue cutting instruments and inner members therefor having flexible couplings

Publication Date: 2011.10.04 B&M PRECISION

AI summary

A flexible inner tubular member for rotation within an angled outer tubular member of a rotary tissue cutting instrument includes a distal end having a cutting element, a proximal end connectible with a powered surgical handpiece, and a flexible coupling between the distal end and the proximal end for transmitting torque to rotate the cutting element while conforming to the angled configuration of the outer member. The flexible coupling comprises inner, middle and outer spiral members, each formed of a flat strip of material, alternately wound in opposite rotational directions. The strips of material that form the inner and outer spiral members have a width intentionally and measurably different from the width of the strip of material that forms the middle spiral member.