Surgical Access Device Seal Assembly
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Solution Overview
Problem
Minimally invasive surgical procedures face challenges in maintaining sterility and preventing gas and liquid leakage due to non-uniform seal deformation when instruments are delivered off-axis or with large diameters through trocar cannulas, resulting in increased resistance and contamination risks.
Innovation Solution
A surgical access device with a seal assembly positioned at the neutral point of the cannula, which can expand radially and includes a combination of seal configurations such as multi-layer conical seals, duckbill seals, and fan seals, integrated with the cannula to maintain contact and reduce radial displacement, along with an obturator notch to align with the seal and minimize deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal element is disposed within the housing to maintain a closed environment, then sterility is preserved and liquid/gas leakage is prevented, but seal deformation occurs when instruments are delivered off-axis or with large diameters, reducing seal effectiveness
Solution Approach 1:
The seal assembly is designed to change its physical parameters (radial dimension) in response to instrument insertion. The seal can radially expand to accommodate large diameter instruments and radially contract to engage instruments during rotation, maintaining sealing effectiveness despite variations in instrument size and insertion angle.
Solution Approach 2:
The seal assembly transitions from a static sealing component to a dynamic one that can radially expand and contract. This dynamic behavior allows the seal to adapt to different instrument diameters and maintain contact with the instrument outer surface during rotation about the neutral point, preventing leakage while accommodating off-axis delivery.
2Ease of operation
If a large diameter instrument is forced through a small diameter seal, then instrument delivery is achieved, but significant increase in normal force subjects the instrument shaft to increased drag or resistance
Solution Approach 1:
The seal assembly dynamically changes its radial dimension to match the instrument diameter. When a large diameter instrument is inserted, the seal radially expands to accommodate it, maintaining an appropriate clearance that reduces friction and drag force on the instrument shaft during insertion and manipulation.
Solution Approach 2:
The seal assembly is divided into multiple seal members that can independently deform and expand radially. This segmentation allows each seal member to flexibly adapt to the instrument diameter, reducing the normal force between the seal and instrument shaft, thereby minimizing drag and resistance during instrument manipulation.
3Reliability
If the seal is positioned to maintain contact during instrument rotation about the neutral point, then sterility is maintained, but the seal must accommodate both small and large diameter instruments
Solution Approach 1:
The seal assembly is positioned at the neutral point and designed to dynamically radially expand and contract to maintain continuous contact with instruments of varying diameters during rotation. This dynamic adaptation ensures sterility is maintained while accommodating both small and large diameter instruments without compromising sealing effectiveness.
Solution Approach 2:
The seal members can change their radial dimension to match different instrument diameters. This parameter change capability allows the same seal assembly to effectively seal around both small and large diameter instruments while maintaining contact during rotation about the neutral point, ensuring sterility without requiring multiple different seals.
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 solution effectively maintains sterility, reduces leakage, and minimizes drag force during instrument insertion, ensuring efficient and reliable access to body cavities while maintaining seal integrity and reducing resistance.
Implementation Method 1
The portion of the sidewall formed by the seal can be adapted to expand radially upon insertion of a large instrument through the cannula
Implementation Method 2
the effectiveness of the seal may diminish, as off-axis delivery results in a disproportionate force being applied to one portion of the seal. This can result in non-uniform deformation of the seal which can reduce the seal's ability to effectively engage an outer surface of an instrument
Data Source
AI summary
Methods and devices for accessing a body cavity are disclosed. In general, a surgical access device is provided that can include a cannula that defines a working channel that is sized and configured to receive a surgical instrument. A seal can be disposed in the cannula of the surgical access device. In one exemplary embodiment, the seal can be positioned at a point in the cannula that is effective to maintain contact between the seal and an instrument inserted therethrough as the instrument is rotated about that point.