Flexible Trocar Seal Compensates for Lateral Shaft Offset

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Minimally invasive surgical trocars face leaks due to lateral offset or angled insertion of instruments with varying shaft diameters, leading to gas escape and loss of insufflation during minimally invasive procedures.

Innovation Solution

A flexible enveloping body composed of a series of ring elements with 90° offset connections provides stability and flexibility, ensuring even contact between the seal and shaft, while a conical expansion cone and elastic seal work together to maintain tightness, with the enveloping body compensating for misalignments and preventing leaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid expansion cone and elastic seal assembly is used to maintain seal stability, then sealing reliability is improved, but lateral flexibility is reduced causing misalignment with offset shafts

Engineering Contradiction:

Improvesealing reliabilityVSAvoidlateral flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The enveloping body is divided into multiple individual ring elements connected by flexible connections, allowing each ring to move independently to accommodate lateral offset while maintaining overall structural integrity and sealing reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The enveloping body is constructed as a flexible structure composed of thin ring elements and connecting walls that can deform laterally to adapt to offset shaft positions while preserving the seal's sealing function

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the enveloping body is made highly flexible to accommodate offset shafts, then adaptability is improved, but structural stability is reduced leading to uneven seal contact

Engineering Contradiction:

Improvelateral flexibilityVSAvoidstructural stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The enveloping body is segmented into discrete ring elements connected by flexible joints, providing localized flexibility while maintaining overall structural stability through the distributed ring structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The enveloping body combines rigid ring elements with flexible connecting walls to create a composite structure that exhibits both stability from the rigid rings and flexibility from the connecting walls

Inventive Principle:

Principle #40Composite materials

3Device complexity

If conventional seals are used without a flexible enveloping body, then device complexity is reduced, but sealing performance deteriorates due to lateral offset leaks

Engineering Contradiction:

Improvestructure complexityVSAvoidsealing performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The flexible enveloping body made of thin ring elements provides lateral adaptability to maintain seal contact with offset shafts without requiring complex active control mechanisms

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible enveloping body automatically adapts its shape to accommodate offset shafts through passive elastic deformation of the ring elements, eliminating the need for active sensing or control systems

Inventive Principle:

Principle #25Self-service

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 ensures a gas-tight trocar system by centering the shaft within the seal, preventing leaks and maintaining insufflation, while being easy to manufacture and adaptable to different instrument sizes and shapes.

Implementation Method 1

an elastic, conical seal is arranged in the trocar, which narrows from proximal to distal... the expansion cone and seal extend diametrically away from one another

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a lateral offset of an inserted shaft is compensated and thus does not lead to a leak... the seal and the spreading device are accommodated in a flexible enveloping body

Methodology Applied

Scientific EffectRadial movement:

Data Source

PatentEP2147645B1Medical instrument with laterally mobile seal

Publication Date: 2014.12.31 KARL STORZ SE & CO KG

Figure 1
Figure 2
Figure 3~4

AI summary

The invention relates to a medical instrument with a cannula (12) through which the shafts of other instruments with different shaft diameters can be passed, with a seal (14) having an opening (16) with a variable cross-section through which the shafts with different diameters can be passed tightly, and with a spreading device for spreading the opening (16) of the seal (14). The spreading device has a spreading cone (20, 81) with several lamellae (22, 84) pivotably mounted on an annular body (24, 82), forming a spreading body that tapers from proximal to distal and connects distally with the seal (14) in the region of the opening (16). The seal (14) and the spreading device are contained within a flexible housing.