Trocar Cannula Stabilization Seal with Graduated Wall Thickness

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Solution Overview

Problem

Existing trocar systems face challenges in stabilizing and sealing cannulas within the body wall during laparoscopic surgery, leading to potential cannula displacement and gas leaks, which can compromise surgical procedures.

Innovation Solution

A cannula stabilization seal system featuring an inflatable elongate tube with a graduated wall thickness, including a sealing cuff and a distal-end region that expands into a toroid shape for secure fixation and gas-tight sealing, allowing for easy integration with various cannulas and access ports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cannula surface is made smooth to facilitate easy and safe placement through the body wall, then the ease of insertion is improved, but the retention characteristics deteriorate, causing the cannula to slip or protrude

Engineering Contradiction:
Improveease of insertionVSAvoidretention characteristics
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The cannula surface is segmented into different zones: a smooth proximal portion for easy insertion and a distal portion with retention features (transverse flutes or grooves) for secure anchoring. This segmentation allows each zone to perform its specific function optimally without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different surface qualities are applied to different locations of the cannula. The proximal end maintains a smooth surface for easy passage through tissue, while the distal end incorporates localized retention features such as transverse flutes or grooves that provide friction and mechanical interlocking with the body wall tissue.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the cannula is secured firmly in place to prevent displacement, then the stability is improved, but the ease of insertion deteriorates due to increased resistance

Engineering Contradiction:
Improvecannula fixationVSAvoidease of insertion
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The cannula is divided into an insertion portion and a retention portion. The insertion portion has a smooth surface that minimizes resistance during placement, while the retention portion with flutes or grooves engages the tissue after insertion is complete, providing secure fixation without impeding the insertion process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retention features are designed to engage the tissue automatically after the cannula is inserted, without requiring additional manipulation. The transverse flutes or grooves create immediate mechanical interlocking with the body wall tissue as the cannula is pushed through, securing the cannula in place as part of the insertion process itself.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a stabilization seal is added to prevent cannula displacement and provide sealing, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvecannula stabilization and sealingVSAvoidtrocar system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stabilization and sealing functions are merged into a single integrated structure. The distal portion of the cannula incorporates both the retention features (transverse flutes or grooves) for stabilization and the sealing interface for gas-tight sealing against the body wall tissue, eliminating the need for separate stabilization and sealing components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The distal portion of the cannula serves multiple functions simultaneously: it provides mechanical retention through transverse flutes or grooves, creates a gas-tight seal against the body wall, and maintains structural integrity during instrument manipulation. This multi-functional design reduces overall system complexity by consolidating multiple functions into a single component.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 stabilization seal effectively prevents cannula displacement and maintains a gas-tight seal, reducing the risk of injury and procedural complications while allowing for easy replacement and cost-effective manufacturing.

Implementation Method 1

a portion of the sealing cuff includes an integrally formed, substantially annular elastomeric seal portion that exhibits strong hoop force on the outer surface of the cannula to seal around the cannula in gas-tight arrangement

Methodology Applied
Scientific EffectHoop force:

Implementation Method 2

the distal end region has a second wall thickness smaller than the wall first wall thickness such that the distal end region (280) is expandable to form a balloon

Methodology Applied
Scientific EffectElastic expansion: Elasticity

Data Source

PatentEP2891463B1Trocar system including cannula stabilization seal
Publication Date: 2017.05.03 APPL MEDICAL RESOURCES CORP
  • EP2891463B1 patent drawingFigure 1
  • EP2891463B1 patent drawingFigure 2
  • EP2891463B1 patent drawingFigure 3~5

AI summary

A stabilization seal is used with existing cannulas for forming a gas-tight seal with tissue in a body wall. The stabilization seal includes a cylindrical inflatable elongate tube having a graduated wall-thickness that is thicker in a central region and thinner in a distal-end region. The tube includes a sealing cuff, having an inflation port, for sealing around a cannula. Application of inflation pressure greatly expands the distal-end region while the central region expands slightly. Another embodiment of a stabilization seal includes an inflatable thread that is used with a cannula having a helical channel on its outer surface. An inflatable tube is wound into the channel. A distal end of the tube includes a gas-tight seal and a proximal end of the tube includes an inflation port. In the uninflated condition the nested tube is flush with the channel. Inflating the tube enlarges the cannula assembly.