Expandable Cannula Seal for Laparoscopic Tool Exchange
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Solution Overview
Problem
Current surgical seals are often designed to accommodate specific shaft sizes, leading to procedural issues such as damage or gas leaks when exchanging tools during minimally-invasive or laparoscopic surgeries, as they fail to accommodate a range of instrument sizes effectively.
Innovation Solution
An expandable cannula seal assembly that includes a housing with a first seal and elongated segments, which converge to form a neck that expands to accommodate different instrument shaft sizes by biasing the segments against the seal's side wall, maintaining an effective seal without changing the offset dimension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-size seal is used to accommodate specific shaft sizes, then the seal can provide a reliable seal for that specific size, but it cannot accommodate instruments with different shaft sizes, leading to gas leaks or damage during tool exchange
Solution Approach 1:
The seal transitions from a fixed static structure to a dynamic expandable structure. The seal can change its internal diameter to accommodate different instrument shaft sizes while maintaining reliable sealing contact. The expandable nature allows the seal to adapt its dimensions dynamically based on the inserted instrument, preventing gas leaks across varying sizes.
Solution Approach 2:
The seal's physical parameters (specifically its internal diameter and cross-sectional area) are made variable rather than fixed. By changing the seal's dimensional parameters in response to different instrument insertions, the seal maintains its sealing function across a range of shaft sizes, resolving the contradiction between adaptability and reliability.
2Adaptability or versatility
If a larger seal opening is used to accommodate bigger instruments, then larger instruments can pass through, but smaller instruments cannot be sealed effectively, causing insufflation gas leaks
Solution Approach 1:
The seal opening dynamically adjusts its size to match the inserted instrument. When a smaller instrument is inserted, the seal contracts to maintain sealing contact, preventing gas leakage. When a larger instrument is inserted, the seal expands to accommodate it. This dynamic adjustment eliminates the harmful effect of gas leakage across different instrument sizes.
Solution Approach 2:
The single seal structure is designed to perform multiple sealing functions for instruments of varying sizes. Rather than requiring different seals for different instrument sizes, this universal seal can adapt its opening size to seal effectively around any instrument within the designed range, preventing gas leakage in all cases.
3Reliability
If multiple fixed-size seals are used to cover different shaft sizes, then each seal can provide reliable sealing for its specific size, but the device complexity increases and tool exchange becomes less efficient
Solution Approach 1:
Multiple sealing functions that would traditionally require separate fixed-size seals are merged into a single expandable seal structure. This unified seal can perform the sealing function for multiple instrument sizes, reducing the total number of seal components while maintaining reliable sealing effectiveness across the size range.
Solution Approach 2:
A single seal component is designed to universally accommodate multiple instrument shaft sizes through its expandable capability. This eliminates the need for multiple specialized seals, simplifying the device while maintaining reliable sealing for each instrument size through dynamic adaptation.
4Stability of the object's composition
If a rigid seal structure is used to maintain seal shape, then the seal can provide consistent sealing geometry, but it cannot expand to accommodate different instrument sizes
Solution Approach 1:
The seal structure transitions from rigid to dynamically flexible. The seal can change its shape and size while maintaining structural integrity through controlled deformation. This allows the seal to expand and contract to accommodate different instrument sizes while preserving the necessary sealing geometry and compositional stability during each sealing state.
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 expandable cannula seal allows for seamless exchange of instruments with varying shaft diameters during surgery, preventing leaks and maintaining insufflation pressure, thus enhancing the efficiency and convenience of minimally-invasive procedures.
Implementation Method 1
a neck that expands to accommodate different instrument shaft sizes by biasing the segments against the seal's side wall
Data Source
AI summary
A medical device can include a housing, a first seal structure, and a seal expander. The first seal structure can have a proximal end and a distal end, and a side wall surrounding and defining an interior chamber. A seal wall can be connected to the side wall and include an expandable opening. A seal expander can be coupled to the housing, and can be at least partially in the interior chamber of the first seal structure. The seal expander can include an expandable neck portion and a seal interface portion, the seal interface portion being near an intersection of the side wall and the seal wall.