Rotating Slit Trocar Cannula Fixation
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Solution Overview
Problem
Existing trocar systems lack sufficient fixation and stabilization in laparoscopic surgeries, particularly in abdominal procedures, leading to potential cannula displacement and tissue trauma due to smooth cannula surfaces, and existing solutions do not adequately address the need for retention without increasing insertion force or causing tissue damage.
Innovation Solution
A trocar fixation device comprising an elongate tube with slits arranged in rows, which can be activated by rotating the tube to form ridges on its exterior surface for secure anchoring in the body wall, and deactivated to return to a smooth surface for easy insertion and removal, providing a gas-tight seal and minimizing tissue trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cannula surface is made smooth to facilitate easy insertion and safe passage through the body wall, then the ease of operation is improved, but the retention characteristics deteriorate causing potential cannula displacement
Solution Approach 1:
The cannula surface is made dynamically changeable through a coating layer that can transition between smooth and textured states. The coating includes a release layer for easy insertion and a retention layer that can be activated to provide friction-based anchoring in the body wall, allowing the surface properties to adapt to different operational phases.
Solution Approach 2:
The surface friction parameter of the cannula is changed by applying a coating layer with different friction characteristics. The coating can be manipulated to change its friction coefficient, providing low friction during insertion and high friction during retention, thus resolving the contradiction between ease of insertion and retention characteristics.
2Reliability
If fixation features such as raised threads or rings are added to the cannula exterior to improve retention, then the retention characteristics are improved, but the insertion force required increases and tissue trauma may occur
Solution Approach 1:
The coating layer is designed to be dynamically manipulable, allowing the surgeon to smooth the surface for easy insertion without resistance, then activate the retention layer to provide fixation features only when needed. This eliminates the need for permanent raised threads or rings that would increase insertion force and cause tissue trauma.
Solution Approach 2:
The fixation features are extracted from the permanent cannula structure and placed into a separate, manipulable coating layer. This allows the fixation function to be applied only when needed, rather than being permanently present on the cannula surface, thus avoiding increased insertion force and tissue trauma.
3Stability of the object's composition
If a fixation mechanism is deployed to anchor the cannula securely in the body wall to prevent displacement during instrument manipulation, then the stability is improved, but the complexity of the device increases
Solution Approach 1:
The coating layer serves multiple functions: it provides a release layer for easy insertion, a retention layer for friction-based anchoring, and can be manipulated to transition between these states. This multi-functionality reduces device complexity by combining multiple fixation mechanisms into a single, manipulable coating layer rather than requiring separate complex fixation components.
Solution Approach 2:
The coating layer is designed to be self-manipulable through surgical instrumentation, allowing the surgeon to smooth or texture the surface as needed without requiring external fixation devices or complex mechanisms. The coating itself provides the fixation function through its own material properties when manipulated, reducing overall device complexity.
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 device effectively anchors the cannula in the body wall, preventing displacement during instrument manipulation and minimizing tissue damage by providing a secure yet easily deployable fixation mechanism that maintains a gas-tight seal, addressing the limitations of existing solutions.
Implementation Method 1
the material of the elongate tube positioned between adjacent slits is compressed and forced radially outward to form ridges in the exterior surface of the elongate tube
Implementation Method 2
The ridges formed on the exterior surface of the elongate tube provide frictional engagement with the body wall to prevent cannula displacement
Implementation Method 3
the exterior surface of the elongate tube returns to a substantially smooth condition
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A trocar fixation device includes a cannula and an elongate tube mounted onto and coupled to the exterior surface of the cannula with the distal end of the cannula extending distally beyond the distal end of the elongate tube. The elongate tube includes a plurality of slits cut at an angle to a longitudinal axis of the elongate tube. The trocar fixation device is activated by rotating the proximal-end region of the elongate tube in a first direction and is deactivated by rotating the proximal-end region of the elongate tube in a second direction, opposite to the first direction . Activation of the trocar fixation device compresses the material positioned between adjacent slits and forces the material radially outwardly, away from the exterior surface of the cannula, thereby forming ridges. Deactivation of the trocar fixation device returns the exterior surface of the elongate tube to a substantially smooth condition.