Adjustable Infusion Cannula with Locking Hub
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Solution Overview
Problem
Infusion cannulas of fixed lengths can cause damage and inefficiency during ophthalmic surgeries, as longer cannulas may obstruct the surgeon's view while shorter ones may lead to suprachoroidal or subretinal infusion, necessitating frequent changes which are damaging and cumbersome.
Innovation Solution
An adjustable length infusion cannula with a locking mechanism that allows the cannula to be extended to different lengths, enabling surgeons to adjust the depth without removing and reinserting the cannula, using a combination of collet and ring mechanisms or annular grooves and detents to secure the cannula at various depths within the hub.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 6 mm infusion cannula is used to ensure complete passage through thickened choroid, then suprachoroidal or subretinal infusion is prevented, but the surgeon's view is obstructed by blocking certain areas of the eye
Solution Approach 1:
The cannula incorporates a telescopic mechanism with movable inner and outer segments that allow dynamic adjustment of the effective cannula length. The inner cannula can slide relative to the outer cannula, enabling the surgeon to extend the cannula to 6 mm when needed to reach through thickened choroid, then retract it to 4 mm to clear the surgical view, all without removing the cannula from the eye
2Ease of operation
If a 4 mm infusion cannula is used to maintain clear surgeon's view, then the surgeon can see peripheral retina, but suprachoroidal or subretinal infusion may occur in eyes with thick choroid
Solution Approach 1:
The telescopic mechanism allows the cannula to be extended from 4 mm to 6 mm by sliding the inner cannula outward, enabling the surgeon to adapt the cannula length to the specific anatomical requirements of each case, ensuring reliable passage through thickened choroid when needed while maintaining clear view when the shorter length suffices
3Adaptability or versatility
If the surgeon removes and reinserts cannulas of different lengths during surgery, then the appropriate cannula length can be selected for each case, but the procedure becomes damaging and cumbersome to the eye
Solution Approach 1:
The telescopic mechanism is locked in place using a locking mechanism that secures the inner cannula at the desired position, allowing the surgeon to adjust the cannula length in-situ without removal. This eliminates repeated punctures and manipulations of the eye, reducing trauma and improving patient comfort while maintaining the ability to adapt to different anatomical requirements
Solution Approach 2:
The cannula design features an inner cannula nested within an outer cannula, with the inner cannula slideable within the outer cannula. This nested structure enables length adjustment while maintaining a compact form factor and providing structural support, allowing the surgeon to achieve variable effective length from a single cannula device
Data Source
AI summary
Certain embodiments provide an adjustable length infusion cannula having a cannula including a first proximal end and a first distal end, and a hub having a second proximal end, a second distal end, and a central aperture that extends between the second proximal end and the second distal end. The central aperture is configured to accept the first distal end of the cannula and allow the cannula upward movement and downward movement through the hub. The adjustable length infusion cannula also includes a locking mechanism configured to lock the cannula within the hub such that the first distal end extends a first distance past the second distal end of the hub.