Cannula Seal Assembly with Flexible Thread and Dual Seals

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Solution Overview

Problem

Traditional cannulas with rigid bodies and threads cause trauma and risk of injury at the surgical site, and their seals can lead to uncontrolled fluid leaks when instruments are passed through.

Innovation Solution

A cannula with a rigid body and a flexible thread or sleeve, designed to minimize interference during insertion and provide strong fixation at the surgical site, combined with a cannula seal assembly that includes primary and secondary seals to control fluid flow and prevent leaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid threads are used on the cannula body, then strong fixation at the surgical site is achieved, but tissue trauma and risk of injury increase

Engineering Contradiction:
Improvefixation strengthVSAvoidtissue trauma
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by using a flexible thread made of soft material that extends along the cannula body. The flexible thread provides fixation functionality while being compliant enough to minimize tissue trauma during insertion and engagement, resolving the contradiction between strong fixation and reduced tissue injury.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the material parameter of the thread from rigid to flexible/soft material. This parameter change allows the thread to maintain fixation strength through its structural configuration while the soft material property reduces tissue trauma and injury risk during surgical procedures.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a seal is placed at the proximal end of the cannula, then fluid flow is limited, but uncontrolled projectile fluid leaks occur when instruments are passed through

Engineering Contradiction:
Improvefluid flow controlVSAvoiduncontrolled fluid leaks
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the sealing function into multiple segments: a primary seal at the proximal end for fluid flow control, and a secondary seal positioned to manage leaks. This segmentation allows the system to maintain reliable fluid control while providing a backup mechanism to prevent uncontrolled projectile leaks when instruments pass through.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements prior cushioning by positioning a secondary seal in advance to catch and contain any fluid that leaks from the primary seal when instruments are inserted. This preparatory sealing arrangement prevents uncontrolled fluid projection and directs leaks into a controlled containment area.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If a rigid cannula body is used, then a stable tube-like structure is maintained for passing instruments, but additional trauma and injury risk are caused during insertion

Engineering Contradiction:
Improvestructural stabilityVSAvoidtissue trauma during insertion
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by covering the rigid cannula body with a flexible sleeve that extends along at least a portion of the cannula body. The flexible sleeve provides a compliant outer surface that reduces tissue trauma during insertion, while the underlying rigid cannula body maintains the necessary structural stability for instrument passage.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure combining a rigid cannula body with a flexible sleeve covering. This composite design integrates the structural stability of rigid material with the trauma-reducing properties of flexible material, allowing the cannula to maintain its tube-like structure while minimizing injury during insertion.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4218631B1Cannula seal assembly
Publication Date: 2025.06.11 CONMED CORP
  • EP4218631B1 patent drawingFigure 1
  • EP4218631B1 patent drawingFigure 2
  • EP4218631B1 patent drawingFigure 3

AI summary

A cannula seal assembly with a compatible flexible cannula. The cannula includes a rigid cannula body having proximal and distal body ends. The cannula body is composed of material having a first thickness. A flexible thread extends along at least a portion of the cannula body from the distal body end toward the proximal body end. The thread is composed of material having a second thickness, which is less than a first thickness. The cannula is attachable to a cannula seal assembly. The assembly includes a housing having a primary seal and a secondary seal therein. The assembly has a spacer connected between the primary seal and the secondary seal and a reservoir between the primary seal and the secondary seal.