Centering Mechanism for Surgical Access Seal Integrity
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Solution Overview
Problem
Surgical access assemblies for minimally invasive surgery face challenges in maintaining a robust and durable seal during manipulation of surgical instrumentation, leading to potential dynamic leaks due to buckling or bending of conventional seal members.
Innovation Solution
The surgical access assembly incorporates a centering mechanism with a flange seal member and a seal assembly, featuring a plurality of coils and a retainer frame assembly, which biases the valve assembly towards a centered position, ensuring a sealing relation with multiple engagement points on the instrument valve housing, and includes a guard assembly to protect the seal during instrument insertion and manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seal member is used in the surgical access assembly, then the structure is simple, but the seal integrity is compromised due to buckling or bending during manipulation of surgical instrumentation
Solution Approach 1:
The centering mechanism is divided into multiple coils (typically three coils arranged in an equilateral triangle pattern) that work together to provide centering force. Each coil acts as an independent element that can compress and expand, allowing the mechanism to maintain seal integrity while accommodating radial movements of the surgical instrument without requiring a completely rigid complex structure.
Solution Approach 2:
The centering mechanism employs springs or elastic elements that can dynamically adjust their compression state in response to radial movements of the surgical instrument. When the instrument moves radially, the coils compress on one side and expand on the other, providing continuous centering force. This dynamic behavior allows the mechanism to maintain seal integrity while adapting to operational conditions without requiring excessive structural complexity.
2Reliability
If the seal member is made more robust to prevent dynamic leaks, then the sealing capability improves, but the ability to adjust to surgical instrument manipulation is reduced
Solution Approach 1:
The centering mechanism changes the physical parameters (position and compression state) of the seal assembly in response to radial movements of the surgical instrument. The springs or elastic elements compress and expand, dynamically adjusting the position of the seal member to maintain optimal sealing contact with the instrument while accommodating variations in instrument diameter and shape during manipulation.
Solution Approach 2:
The centering mechanism automatically adjusts to radial movements of the surgical instrument through the elastic properties of the coils. When the instrument moves radially, the mechanism self-adjusts by compressing on the compressed side and expanding on the opposite side, providing continuous centering force without requiring external control or complex actuation systems.
3Duration of action of stationary object
If a centering mechanism with multiple coils is introduced, then the seal durability is improved, but the device complexity increases
Solution Approach 1:
The centering mechanism is segmented into multiple independent coils arranged in a triangular pattern, with each coil providing centering force in a specific direction. This segmentation allows the mechanism to maintain durability through distributed load bearing while keeping each individual coil element relatively simple in design, avoiding the need for a single complex rigid structure.
Solution Approach 2:
The centering mechanism with multiple coils serves multiple functions: it provides centering force, accommodates radial movements, maintains seal contact, and absorbs mechanical stresses. By integrating these multiple functions into a single mechanism using simple elastic elements, the design achieves enhanced seal durability without proportionally increasing 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
This configuration enhances sealing integrity and durability, reducing dynamic leaks by maintaining contact with the instrument valve housing during radial movement and returning to a centered position after instrument withdrawal, thus preventing seal compromise.
Implementation Method 1
The centering mechanism may be formed of a resilient material to transition the centering mechanism between a first state, in which, the central opening of the centering mechanism is disposed in a generally centered position, and a second state, in which, the central opening is radially displaced from the generally centered position.
Implementation Method 2
The flange seal member includes an arcuate portion configured to adjustably engage first and second surfaces of the instrument valve housing in a sealing relation.
Data Source
AI summary
An access assembly includes an instrument valve housing defining a cavity, and a valve assembly. The valve assembly includes a flange seal member, a seal assembly, a centering mechanism, and a retainer frame assembly. The flange seal member includes an arcuate portion configured to adjustably engage first and second surfaces of the instrument valve housing in a sealing relation. The centering mechanism is configured to bias the valve assembly towards a generally centered position within the cavity. The centering mechanism includes a plurality of coils including inner coil portions operatively secured with the seal assembly, and outer coil portions configured to engage the first surface of the instrument valve housing. The retainer frame assembly includes first and second members. The inner coil portion of the centering mechanism is disposed between seal assembly and the second member of the retainer frame assembly.