Trocar Cannula Tab Member Retention Mechanism
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Solution Overview
Problem
Existing microsurgical instruments, such as trocar cannulas, face challenges in maintaining their position within the eye during instrument exchanges, leading to potential injury due to inadvertent movement, requiring additional steps and manual intervention to prevent dislodgement.
Innovation Solution
A trocar cannula with a cantilever tab member that is selectively moveable between a relaxed and deformed position, engaging with tissue to provide increased retention force, allowing automatic return to a relaxed state for easy removal, eliminating the need for external forceps during instrument exchanges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If friction between the trocar cannula outer surface and sclera is relied upon to maintain position, then the cannula can be easily inserted, but the cannula may be inadvertently moved during instrument exchange causing injury
Solution Approach 1:
The tab member is designed to be dynamically changeable between a relaxed state (allowing easy insertion) and a deformed state (providing frictional engagement for stability). The tab member selectively deforms when a medical instrument is introduced into the cannula, transitioning from a non-engaging to an engaging state, thereby adapting the retention mechanism to the surgical phase.
Solution Approach 2:
The tab member's physical state changes in response to internal pressure from instrument insertion. When pressure is applied, the tab member deforms to a position where it frictionally engages the sclera, increasing the normal force and frictional retention. When pressure is released, the tab returns to its relaxed state, reducing engagement force for easy removal.
2Reliability
If forceps are used to grasp the cannula hub during instrument exchange, then cannula position can be maintained, but an extra step is required increasing surgery length
Solution Approach 1:
The cannula system performs its own retention function through the tab member that automatically engages with the sclera when an instrument is inserted. The system serves itself by using the instrument insertion action to trigger tab deformation, eliminating the need for external forceps assistance during instrument exchanges.
Solution Approach 2:
The tab member is pre-positioned in a relaxed state ready to engage. When the instrument is inserted, it automatically triggers the tab to deform into the engaged state before the instrument exchange is complete, ensuring retention is established in advance without requiring additional manual intervention.
3Reliability
If forceps are used to hold the cannula, then position stability is maintained, but an extra hand is required reducing surgical efficiency
Solution Approach 1:
The cannula system performs its own retention function through the tab member that automatically engages with the sclera when an instrument is inserted. The system serves itself by using the instrument insertion action to trigger tab deformation, eliminating the need for external forceps assistance during instrument exchanges.
4Reliability
If the tab member is always in a deformed position providing retention force, then cannula stability is improved, but the cannula cannot be easily moved or removed
Solution Approach 1:
The tab member is designed to be dynamically changeable between a relaxed state (allowing easy insertion) and a deformed state (providing frictional engagement for stability). The tab member selectively deforms when a medical instrument is introduced into the cannula, transitioning from a non-engaging to an engaging state, thereby adapting the retention mechanism to the surgical phase.
Solution Approach 2:
The tab member's physical state changes in response to internal pressure from instrument insertion. When pressure is applied, the tab member deforms to a position where it frictionally engages the sclera, increasing the normal force and frictional retention. When pressure is released, the tab returns to its relaxed state, reducing engagement force for easy removal.
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
This solution enhances surgical efficiency by reducing procedure time and allowing the surgeon a free hand, while ensuring stable cannula positioning without manual retention, thereby minimizing the risk of injury and streamlining the surgical process.
Implementation Method 1
the tab member frictionally engages the tissue to retain the cannula with respect to the tissue
Implementation Method 2
the tab member is biased into the relaxed position, but may be selectively moved into the deformed position by introduction of a medical instrument into the cannula
Data Source
AI summary
A trocar cannula is disclosed. The trocar cannula comprises a cannula having at least one tab member formed therein. Each tab member is configured to provide a retention force between the cannula and tissue when the tab member is placed in a deformed position. The tab member is selectively moveable between a relaxed position, in which the cannula may be moved with respect to the tissue, and the deformed position, wherein the tab member frictionally engages the tissue.