Tissue Expander Slidable Rim Vacuum Seal
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Solution Overview
Problem
Existing external vacuum expanders face challenges in maintaining a sustained vacuum, balancing distractive forces with counterforces to prevent capillary collapse, and reducing shear stresses that cause skin irritation and ulceration, particularly due to the complex surface contours of the torso and significant variations in movement.
Innovation Solution
A dome-shaped device with a deeply concave, wide, tapered, soft rubber skirt that deflects to maintain an air-tight seal and reduces shear stresses by increasing the skin contact area, allowing the skin to recruit peripheral tissue to dissipate forces, while a lubricated interface minimizes friction and adhesion, enabling comfortable and prolonged use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid rim is used to maintain vacuum seal, then the vacuum seal is improved, but shear stress on the skin increases causing irritation and ulceration
Solution Approach 1:
The patent replaces the rigid rim with a flexible membrane that can conform to skin contours while maintaining the vacuum seal. This flexible membrane reduces shear stress by allowing relative movement between the device and skin, preventing the concentrated shear forces that cause irritation and ulceration.
Solution Approach 2:
The patent introduces a dynamic element (the flexible membrane) that can adapt its shape and position in response to skin movement and contours. This dynamic adaptation maintains the vacuum seal while distributing forces evenly, reducing the harmful shear stress concentration at fixed rigid boundaries.
2Object-affected harmful factors
If the rim surface area is increased to reduce counter pressure, then pressure ulceration is prevented, but device complexity increases
Solution Approach 1:
The flexible membrane inherently provides a large surface area that conforms to the skin, distributing pressure evenly without requiring complex structural elements. The membrane's flexibility allows it to adapt to skin contours, increasing effective contact area and reducing pressure points while maintaining device simplicity.
3Reliability
If adhesive is used to secure the device to skin, then vacuum preservation is improved, but skin irritation and damage increase
Solution Approach 1:
The flexible membrane creates a mechanical seal through its ability to conform and adhere to skin contours via elastic deformation and surface tension, eliminating the need for chemical adhesives. This physical sealing mechanism preserves the vacuum while avoiding the skin irritation and damage associated with adhesive materials.
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 preserves the vacuum, balances forces to prevent capillary collapse, and significantly reduces shear stresses, leading to improved tissue expansion with reduced skin irritation and ulceration, making the device suitable for breast augmentation and reconstruction.
Implementation Method 1
a lubricated interface minimizes friction and adhesion, enabling comfortable and prolonged use
Implementation Method 2
apply a vacuum within the shell and impart a distracting force to expand tissue
Data Source
AI summary
A tissue expander configured to be worn by a user having a shell having an aperture formed within the shell to receive tissue expanded by a distracting force. The shell has a skirt providing a skin contact surface area against the skin of the patient, the aperture defining an aperture surface area, wherein the skin contact surface area is greater than the aperture surface area, and wherein the skirt is non-fixedly attached to the skin of the patient and slides laterally outwardly.