Balloon Cannula With Pre-filled Fluid Chamber
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Solution Overview
Problem
Conventional cannulas used in minimally invasive surgical procedures tend to back out of the incision during instrument manipulation due to the pressurized pneumoperitoneum environment, and they often require external pumps or syringes for inflating or deflating the balloon, which can be cumbersome.
Innovation Solution
A surgical access assembly featuring a balloon cannula with a pre-filled fluid chamber and adjustable collars, where the first collar translates to inflate the balloon by transferring fluid from the chamber to the balloon anchor, and the second collar prevents proximal movement to maintain inflation, while translating back to deflate the balloon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cannulas are used in pressurized pneumoperitoneum environment, then the cannula can provide access to the surgical cavity, but the cannula tends to back out of the incision during instrument manipulation
Solution Approach 1:
The balloon is pre-filled with a controlled amount of fluid (e.g., 3-5 mL) before insertion, allowing it to be inserted in a deflated state and then inflated once positioned. This preliminary preparation enables the balloon to provide immediate anchoring force upon inflation, preventing cannula backout during subsequent instrument manipulation while maintaining ease of initial insertion and positioning
2Ease of operation
If external pumps or syringes are coupled to the cannula to inflate or deflate the balloon, then the balloon can be actuated, but the system becomes cumbersome and complex
Solution Approach 1:
The system uses the patient's own physiological pressure (intra-abdominal pressure from pneumoperitoneum, typically 12-15 mmHg) to automatically inflate the balloon by forcing fluid from the reservoir through the cannula into the balloon chamber. Deflation occurs automatically when the cannula is withdrawn, creating negative pressure that draws fluid back into the reservoir. This self-actuating mechanism eliminates the need for external pumps or syringes, significantly reducing device complexity while maintaining ease of operation
Solution Approach 2:
The system exploits hydraulic pressure differential to achieve automatic balloon inflation and deflation. The intra-abdominal pressure during pneumoperitoneum creates a pressure gradient that forces fluid from the reservoir into the balloon, while withdrawal of the cannula creates negative pressure that reverses the flow. This pneumatic-hydraulic mechanism replaces complex mechanical actuation systems with a simple pressure-driven fluid transfer system
3Reliability
If the balloon is inflated to prevent cannula withdrawal, then anchoring stability is improved, but the mechanism for inflating and deflating becomes more complex
Solution Approach 1:
The reservoir, cannula, and balloon are integrated into a single unified system where the reservoir is positioned within the cannula housing and the balloon is attached to the distal end of the cannula. The fluid pathway is continuous and self-contained, with the cannula itself serving as the conduit for fluid transfer. This merging of components eliminates the need for separate external pumps, tubing, and control mechanisms, achieving reliable anchoring through balloon inflation while minimizing 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 solution provides a self-contained mechanism to inflate and deflate the balloon within the cannula, eliminating the need for external devices and preventing cannula withdrawal during procedures, thereby enhancing procedural stability and efficiency.
Implementation Method 1
translating the first collar towards the second position may cause the fluid to be transferred from the chamber to the balloon anchor thereby expanding the balloon anchor
Implementation Method 2
a pre-filled air chamber that is adjustable by a set of collars
Data Source
AI summary
A surgical access assembly includes an elongated cannula member having a proximal end portion and a distal end portion, a balloon anchor coupled to the distal end portion of the elongated cannula member, a sleeve of the balloon anchor extending proximally along an outer surface of the elongated cannula member, a chamber defined between the sleeve of the balloon anchor and the outer surface of the elongated cannula member, and a first collar is coupled to the elongated cannula member. The first collar is slidable along the elongated cannula member and engageable with the sleeve of the balloon anchor.