Pressure-Relief Cannula With Segmented Chambers for Leak Control
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Solution Overview
Problem
Existing cannulas used in arthroscopic or endoscopic procedures suffer from uncontrolled fluid leaks due to disturbance of the seal when instruments are passed through, leading to projectile fluid ejections.
Innovation Solution
A pressure relief device with a cannula body, proximal and distal seals, and a chamber that captures and directs fluid leaks away from the user, preventing uncontrolled ejections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is placed at the proximal end of the cannula to limit fluid flow, then fluid management is improved, but fluid pressure builds up and may cause uncontrolled projectile leaks when the seal is disturbed
Solution Approach 1:
The cannula is divided into multiple sealed chambers (first chamber between proximal seal and first distal seal, second chamber between first distal seal and second distal seal). This segmentation allows fluid pressure to be contained within individual chambers rather than building up across the entire cannula, and enables controlled release from one chamber at a time through port 48, preventing uncontrolled projectile leaks while maintaining reliable fluid management.
Solution Approach 2:
Port 48 serves as an intermediary pressure relief mechanism between the sealed chambers and the external environment. It provides a controlled pathway for fluid to escape from the first chamber when pressure becomes excessive, acting as a safety valve that prevents uncontrolled leaks while maintaining the integrity of the proximal seal for normal fluid management.
2Ease of operation
If instruments are passed through the cannula, then surgical access is improved, but the seal is disturbed causing spontaneous fluid ejections
Solution Approach 1:
By segmenting the cannula into multiple chambers separated by distal seals, the invention ensures that disturbing the proximal seal during instrument passage only affects the first chamber. Fluid can be controlled to release from this single chamber through port 48, rather than causing uncontrolled ejections from the entire cannula system, thus maintaining ease of surgical access while preventing harmful fluid ejections.
Solution Approach 2:
The invention converts the potentially harmful effect of seal disturbance into a controlled benefit. When instruments are passed through and disturb the proximal seal, the built-in pressure relief mechanism at port 48 captures and controls the resulting fluid flow, transforming what would be an uncontrolled projectile leak into a manageable, directed fluid release that actually alerts the surgeon to the seal disturbance.
3Device complexity
If a single seal is used in the cannula, then device complexity is reduced, but fluid pressure control and leak prevention are insufficient
Solution Approach 1:
The cannula incorporates multiple seals (proximal seal, first distal seal, second distal seal) that divide the internal volume into separate chambers. This segmentation provides redundant sealing points that enhance fluid pressure control and leak prevention reliability. Each seal independently manages pressure in its respective chamber, so if one seal is disturbed, the other seals continue to contain fluid in their chambers, preventing catastrophic failure while justifying the increased device complexity through improved safety.
Data Source
AI summary
A pressure relief device for controlling the outflow of fluid from a surgical site. The pressure relief device includes a cannula body having a proximal end and a distal end with a thread extending along the entire cannula body from the distal end. The device also has a proximal end cap connected to the proximal end of the cannula body, a spacer connected between the cannula body and the proximal end cap, and a proximal seal enclosed between the proximal end cap and the spacer. One or more distal seals can be enclosed between the spacer and the proximal end of the cannula body. The device additionally includes a channel between the spacer and an inner wall of the proximal end cap. Fluid flows out of the device through the channel.