Inflatable Surgical Cannula with Dual Membrane Sealing
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Solution Overview
Problem
Existing surgical cannulas lack an effective mechanism for anchoring and sealing to the incision site and for controlling the flow of fluids within the cannula, leading to suboptimal pressure gradients and post-procedure discomfort.
Innovation Solution
A surgical cannula with inflatable membranes on its outer and inner surfaces, utilizing fluid pressure to anchor/seal to the incision site and seal medical instruments, featuring a fluid chamber, one-way valves, and a flow piston to control fluid flow and pressure, allowing discrete control of the anchor/seal membrane and inner sealing membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an internal inflatable membrane is used to seal the lumen, then the sealing capability is improved, but the pressure gradient for positive seal is reduced because the membrane pressure equals the body cavity pressure
Solution Approach 1:
The invention divides the sealing system into two separate membranes: an inner lumen membrane for sealing the lumen and an outer anchor membrane for anchoring to the incision site. This segmentation allows each membrane to operate at different pressure levels, with the outer membrane capable of achieving higher pressure than the body cavity to create a positive pressure gradient for improved sealing.
Solution Approach 2:
The invention applies different functional properties to different parts of the cannula system. The outer anchor membrane is designed with properties suitable for anchoring to tissue (higher pressure capability), while the inner lumen membrane is designed for sealing around instruments. This local differentiation of functional qualities enables the outer membrane to maintain a positive pressure gradient relative to the body cavity.
2Strength
If rigid anchoring protrusions are pressed against the incision site, then the anchoring capability is improved, but post-procedure discomfort increases
Solution Approach 1:
The invention replaces rigid anchoring protrusions with a flexible outer anchor membrane that can be inflated to anchor the cannula to the incision site. This flexible membrane distributes the anchoring force over a larger area and conforms to the tissue, reducing localized pressure and minimizing post-procedure discomfort while maintaining effective anchoring capability.
Solution Approach 2:
The invention uses pneumatic inflation of the outer anchor membrane to achieve anchoring. By injecting fluid into the outer membrane, the membrane expands and presses against the incision site with controlled pressure, providing strong anchoring capability without the need for rigid mechanical protrusions that cause tissue damage and discomfort.
3Device complexity
If a single fluid chamber is used, then the device complexity is reduced, but the ability to individually control anchor and lumen membranes is lost
Solution Approach 1:
The invention segments the fluid chamber into two separate chambers: an inner fluid chamber for the lumen membrane and an outer fluid chamber for the anchor membrane. This segmentation enables independent control of each membrane through separate fluid injection and drainage pathways, allowing the operator to adjust anchor and lumen membranes independently without affecting each other.
Solution Approach 2:
The invention introduces separate one-way valves as intermediaries between the fluid source and each membrane. These valves (inner valve and outer valve) act as control mechanisms that regulate fluid flow to the respective membranes independently, enabling precise control of each membrane's inflation and deflation while maintaining a relatively simple overall device structure.
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 cannula achieves a positive pressure gradient for improved sealing, reduces post-procedure discomfort, and allows for precise control of fluid flow to maintain the cannula's position and seal medical instruments effectively.
Implementation Method 1
The fluid chamber is fluidly connected to the outer membrane through a casing one-way valve
Implementation Method 2
the flow piston is moved in a second direction to move the fluid from the fluid chamber into the outer membrane through the casing one-way valve
Implementation Method 3
The filled fluid is then pressurized to inflate or to increase its volume to anchor/seal the cannula to the incision site
Data Source
AI summary
Disclosed herein are multiple cannulas defining a lumen sized and dimensioned to receive one or more medical instruments, an inflatable outer membrane attached to an outer surface of the cannula, and at least one activator that reversibly activates the cannulas to push a fluid contained in the cannulas into the outer membrane to fill or pressurize the outer membrane. Also disclosed are methods for operating these cannulas.