Reusable Trocar Balancing Feature for Stability
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Solution Overview
Problem
Reusable trocars with robust materials for sterilization and reuse tend to be unstable and prone to tipping due to their increased weight, causing misalignment of the working channel with the targeted operating area during surgical procedures.
Innovation Solution
Incorporating a balancing feature with a proximal thinner section and a distal thicker section in the cannula design, which shifts the center of gravity closer to the tissue engagement ribs, reducing the fulcrum force and torque that can cause the trocar to tip over, thereby maintaining alignment with the targeted area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reusable trocar is made with robust materials for sterilization and reuse, then durability and reusability are improved, but weight increases causing instability and tipping
Solution Approach 1:
The cannula employs varying wall thicknesses along its length, with thicker walls at the proximal end and thinner walls at the distal end. This local quality variation optimizes the distribution of material strength where needed while reducing overall weight and improving balance characteristics for stability during surgical procedures.
Solution Approach 2:
The cannula features an asymmetric design with different wall thicknesses at different locations along its longitudinal axis. The proximal portion has greater wall thickness for strength, while the distal portion has reduced wall thickness, creating an asymmetric mass distribution that improves balance and reduces tipping tendency.
2Reliability
If reusable trocar is made with robust materials for sterilization and reuse, then durability and reusability are improved, but stability deteriorates due to increased weight causing tipping
Solution Approach 1:
The cannula employs varying wall thicknesses along its length, with thicker walls at the proximal end and thinner walls at the distal end. This local quality variation optimizes the distribution of material strength where needed while reducing overall weight and improving balance characteristics for stability during surgical procedures.
Solution Approach 2:
The asymmetric wall thickness design creates a counterbalancing effect where the heavier proximal portion acts as a counterweight to stabilize the cannula during insertion and use, preventing the distal end from tipping or deviating from the intended trajectory.
3Ease of manufacture
If uniform wall thickness is used in cannula design, then manufacturing simplicity is improved, but balance and stability deteriorate
Solution Approach 1:
The cannula employs varying wall thicknesses along its length, with thicker walls at the proximal end and thinner walls at the distal end. This local quality variation optimizes the distribution of material strength where needed while reducing overall weight and improving balance characteristics for stability during surgical procedures.
Solution Approach 2:
The wall thickness parameter is varied along the length of the cannula, transitioning from a uniform thickness design to a graduated thickness design. This parameter change optimizes both manufacturing feasibility and performance characteristics, achieving acceptable balance and stability while maintaining reasonable manufacturing complexity.
Data Source
AI summary
A surgical access device assembly includes a cannula hub and a cannula tube. The cannula tube extends distally from the cannula hub along a longitudinal axis. The cannula tube defines a working channel. The cannula tube includes a tissue engagement feature and a balancing feature. The balancing feature is configured to promote lateral stability of the cannula tube and the cannula hub relative to the body cavity wall of the patient. The balancing feature includes a proximal portion of the cannula tube having a first wall thickness. The balancing feature also includes a distal portion of the cannula tube having a second wall thickness that is greater than the first wall thickness. At least a portion of the proximal portion is proximal relative to the tissue engagement feature. At least a portion of the distal portion is distal relative to the tissue engagement feature.