Surgical Obturator Dual-Shield Mechanism

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Solution Overview

Problem

Current trocar designs with safety shields fail to effectively protect internal organs during laparoscopic procedures due to delayed shield deployment and increased insertion force, often resulting in accidental injuries and fatalities, as the shields either deploy too late or require excessive force to penetrate the body wall.

Innovation Solution

A trocar design featuring an obturator with two independently biased shields, where the first shield covers the piercing tip immediately after entry and the second shield covers the cutting edges once the obturator is fully inserted, utilizing a latching mechanism to prevent premature locking and reduce the risk of accidental injuries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single safety shield is used to cover the trocar tip, then protection of internal organs is provided, but the shield deploys too late after the cutting tip has already contacted internal organs

Engineering Contradiction:

Improveprotection of internal organsVSAvoidshield deployment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The single shield is divided into two independently biased shields: a first shield that covers the piercing tip and a second shield that covers the cutting edges. This segmentation allows each shield to deploy independently at the appropriate time, with the first shield deploying immediately after tip entry to protect internal organs before the plunge effect occurs.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the body wall is filled with carbon dioxide to expand it away from internal organs, then the danger of accidental injury is minimized, but the elastic nature of the body wall causes severe depression at the entry site bringing the tip closer to internal organs

Engineering Contradiction:

Improvedanger of accidental injuryVSAvoidresistance to penetration

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The first shield is biased to automatically cover the piercing tip as soon as it penetrates the body wall, before the plunge effect can occur. This preliminary protective action addresses the elastic rebound issue by ensuring protection is in place before the tip can contact internal organs, regardless of the body wall's elastic deformation.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a safety shield is designed to cover the full diameter of the obturator, then complete protection is provided, but the shield encounters excessive resistance from the body wall during insertion

Engineering Contradiction:

Improvecomplete protectionVSAvoidresistance to shield movement

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The protection system is segmented into two shields of appropriate sizes: the first shield covers only the piercing tip and the second shield covers the cutting edges. This segmentation reduces the surface area of each individual shield, thereby reducing the resistance each shield encounters from the body wall during insertion, while still providing complete protection when both shields are in place.

Inventive Principle:

Principle #1Segmentation

4Loss of time

If the cutting surface of the obturator is reduced to allow shields to cover it, then shield deployment is faster, but excessive force is required to enter the body cavity

Engineering Contradiction:

Improveshield deployment speedVSAvoidforce required for penetration

Core Design Contradiction:

Loss of timeVSForce

Solution Approach 1:

The cutting surface is segmented into two parts: a piercing tip for initial penetration and cutting edges for creating the opening. The first shield covers only the piercing tip and the second shield covers the cutting edges. This segmentation allows each shield to deploy independently at the appropriate stage, maintaining fast deployment speed while preserving the full cutting surface area needed for effective tissue penetration.

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 dual-shield mechanism ensures timely protection of internal structures by covering the piercing tip before the plunge effect occurs, reducing the risk of accidental injuries and facilitating safer and more controlled tissue penetration with reduced insertion force.

Implementation Method 1

A first biasing element is operably mounted to the first shield to bias the first shield in a distal direction

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

A second biasing element is operably mounted to the second shield to bias the second shield in a distal direction

Methodology Applied

Scientific EffectElastic force: Elasticity

Data Source

PatentUS8066729B2Surgical obturator

Publication Date: 2011.11.29 STRYKER CORP

AI summary

An obturator has an elongated shaft with a first shaft portion and a second shaft portion within an obturator housing. The distal end of the first shaft portion creates a first shield and the distal end of the second shaft portion creates a second shield. A blade having a piercing tip and cutting edges is interposed between the first shield and the second shield. In use, once the piercing tip passes the body wall, the first shield moves to cover the piercing tip and protect internal organs from accidental injury while the cutting edges continue to cut the body wall. Once the second shield passes through the body wall, the second shield moves to cover the cutting edges.