Trocar Cannula Balloon Retention and Low-Profile Design
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Solution Overview
Problem
Existing surgical trocar cannulas lack effective fixation and stabilization methods, leading to potential displacement during procedures, increased insertion force, and compromised seals, especially when using inflatable balloons with thick foam bolsters that reduce usable length and increase diameter.
Innovation Solution
A balloon trocar system with an inflatable balloon at the distal end and a bolster at the proximal end, where the balloon is folded during insertion to reduce resistance and insertion force, and then inflated to maintain a seal against the body wall, utilizing a sleeve with an annular ring for interference fit and a low-profile design to minimize diameter and maximize working length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick foam bolster is used to provide fixation and stabilization, then retention is improved, but the usable length of the cannula is reduced and the diameter is increased
Solution Approach 1:
The patent changes the physical state and dimensions of the retention structure by using a low-profile design that minimizes the protrusion from the cannula body. This allows the retention structure to provide fixation without significantly increasing the overall diameter or reducing the usable length of the cannula, resolving the contradiction between reliability and length.
Solution Approach 2:
The patent employs an inflatable balloon that can dynamically adjust its volume and shape. When deflated, it maintains a low profile to minimize diameter increase; when inflated, it provides enhanced retention. This dynamic adjustment resolves the contradiction between needing strong fixation and maintaining acceptable dimensions.
2Reliability
If a thick foam bolster is used to provide fixation and stabilization, then retention is improved, but the diameter of the cannula is increased
Solution Approach 1:
The patent changes the geometric parameters of the retention structure by designing it with a low profile that minimizes radial protrusion. This allows the structure to provide adequate fixation surface area without significantly increasing the cannula diameter, resolving the contradiction between retention and diameter.
Solution Approach 2:
The inflatable balloon provides dynamic adjustment of the retention profile. When deflated, it maintains a minimal diameter increase; when inflated, it expands to provide enhanced fixation. This resolves the contradiction between needing strong retention and maintaining acceptable cannula diameter.
3Reliability
If the balloon is left unfolded during insertion, then it provides immediate retention, but the insertion force is increased and trauma is caused
Solution Approach 1:
The patent employs a dynamically adjustable balloon that transitions from a deflated low-profile state during insertion to an inflated retention state after placement. This dynamic transformation allows the balloon to provide minimal resistance during insertion (reducing force and trauma) while providing effective retention when inflated, resolving the contradiction between immediate retention and insertion force.
Solution Approach 2:
The patent applies preliminary action by deflating the balloon before insertion to reduce its profile and minimize insertion force. After the cannula is properly positioned, the balloon is then inflated to provide retention. This sequential approach resolves the contradiction between needing retention and minimizing insertion trauma.
4Ease of operation
If the cannula surface is made smooth for easy placement, then ease of insertion is improved, but retention characteristics are reduced
Solution Approach 1:
The patent divides the cannula into distinct functional segments: a smooth insertion portion for easy placement and a separate retention structure (inflatable balloon) for fixation. This segmentation allows the insertion surface to remain smooth while the retention function is provided by the balloon, resolving the contradiction between ease of placement and retention characteristics.
Solution Approach 2:
The inflatable balloon provides dynamic retention that can be activated after insertion. The smooth cannula surface facilitates easy insertion, and once positioned, the balloon is inflated to provide the necessary retention characteristics. This dynamic approach resolves the contradiction between smooth surface for easy placement and retention characteristics.
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 system provides controlled and reduced insertion force, enhanced retention, and improved sealing, reducing trauma and maintaining a stable cannula position during prolonged procedures, while maintaining a low profile and minimizing diameter increase.
Implementation Method 1
an elastic balloon is formed as a small inflatable structure... The balloon is inflated and the bolster located toward the proximal end of the cannula is moved distally along the length of the cannula in order to compress the balloon against the inside of the body wall and seal the incision
Implementation Method 2
The annular ring has a third inner diameter in an undisturbed state that is smaller than the second outer diameter of the annular recess to define an interference fit between the sleeve and the cannula
Data Source
AI summary
A cannula assembly having a retention member and a method of manufacture of the cannula assembly is provided. The cannula assembly includes a cannula and a sleeve disposed around the cannula from a proximal end to a distal end. The sleeve can be pre-formed by a stretch blow molding process then advanced over the cannula. The sleeve includes an inflatable balloon and an annular ring distal the inflatable balloon. The cannula includes an annular recess. The annular ring is sized to have an interference fit with the annular recess.