Surgical Instrument Sheath for Pressure Equalization
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Solution Overview
Problem
Minimally invasive surgical instruments face challenges in cleaning and sterilization due to their complex mechanical design, which includes many small components and tight spaces, making them difficult to protect from fluids and debris during use.
Innovation Solution
A replaceable sheath for surgical instruments made of materials like ePTFE that are permeable to gas, allowing pressure equalization and providing a barrier against liquids, with flexible sections to accommodate bending joints and prevent tissue pinching, and optionally coated with lubricants or disinfectants for easier cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a sheath is used to protect the surgical instrument from fluids and debris, then the protection against biomaterial infiltration is improved, but the pressure equalization capability deteriorates
Solution Approach 1:
The sheath is made from a porous material that allows gas permeation while blocking liquid biomaterials. The porous structure enables insufflation gas to pass through and equalize pressure on both sides of the sheath, preventing the pressure differential that would otherwise cause biomaterial infiltration through the sheath or at its interfaces.
2Object-affected harmful factors
If the sheath is made impermeable to block liquids, then the barrier against biomaterial is improved, but the pressure balance capability deteriorates
Solution Approach 1:
The porous material provides selective permeability - the pore structure is designed to block liquid biomaterials while allowing gas molecules to pass through. This enables the sheath to simultaneously function as a liquid barrier and a pressure equalization membrane, resolving the contradiction between biomaterial protection and pressure balance.
3Strength
If the sheath material is made rigid to provide structural support, then the structural integrity is improved, but the flexibility to accommodate bending joints deteriorates
Solution Approach 1:
The sheath is constructed as a flexible shell from porous material that can bend and conform to the contours of the surgical instrument, including bending joints. The flexible nature allows the sheath to accommodate instrument articulation while maintaining its protective function, and the porous structure is maintained throughout to enable pressure equalization even in bent configurations.
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 sheath effectively reduces the risk of biomaterial infiltration, facilitates cleaning, and maintains pressure balance within the instrument, minimizing contamination and the 'straw effect' while allowing for flexible movement without interfering with instrument operation.
Implementation Method 1
The sheath comprises a material that is permeable to gas so as to permit equalization of a pressure differential after insertion of the sheath and shaft into an environment at a surgical insufflation gas pressure
Implementation Method 2
The second section provides a friction seal with the shaft
Data Source
AI summary
A surgical apparatus comprises an instrument shaft having a proximal end and a distal end, an end effector coupled to the distal end of the shaft, and a sheath disposed on an external surface of the instrument shaft. The sheath has a first section made of ePTFE and a second section made of a second material, wherein the second section provides a friction seal with the shaft, and wherein the ePTFE is gas-permeable.