Vitrectomy Probe Friction Reduction via Seal Segmentation
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Solution Overview
Problem
Existing vitrectomy probes face inefficiencies due to high friction between oscillating components, which limits cut rates and precision during microsurgical procedures, particularly in ophthalmic surgeries where delicate tissue management is required.
Innovation Solution
The design incorporates a vitrectomy probe with a reduced number of seals and a smaller diameter drive shaft, minimizing contact area and friction, featuring a fluidic motor-driven cutter assembly with a coupler that reduces the need for aspiration fluid conveyance through the motor, thus employing only two seals for fluid leakage prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If four o-ring type seals are used to seal the aspiration motor tube and diaphragm, then fluid pressure areas are effectively sealed, but friction between moving components increases
Solution Approach 1:
The patent extracts and eliminates the aspiration motor tube from the design, removing the need for four seals around it. Instead, a simplified seal system with only two seals is used, one for the drive shaft and one for the inner cutting member, thereby reducing friction while maintaining sealing effectiveness
Solution Approach 2:
The drive shaft serves multiple functions: it transmits rotational motion from the motor to the inner cutting member and also acts as a seal reference surface for the first seal. This multi-functionality reduces the total number of seals needed while maintaining fluid pressure isolation
2Reliability
If multiple seals are used to prevent fluid leakage, then sealing reliability is improved, but frictional resistance against oscillating components increases
Solution Approach 1:
The patent removes the complex multi-seal system and extracts only the essential sealing functions, implementing a simplified two-seal system that maintains fluid leakage prevention while minimizing frictional resistance on the oscillating cutter
Solution Approach 2:
The sealing function is segmented into two distinct locations: one seal for the drive shaft assembly and another for the inner cutting member. This segmentation allows each seal to be optimized for its specific location and function, reducing overall friction while maintaining effective sealing
Data Source
AI summary
A vitrectomy probe includes a housing, a fluidic motor disposed within the housing, a needle extending from the housing, and a cutter assembly. The cutter assembly includes an inner cutting member disposed within and axially moveable relative to the needle, a drive shaft disposed within the housing and axially moveable relative to the housing, and a coupler disposed within the housing coupling the drive shaft and the inner cutting member. The motor is associated with the drive shaft in a manner that drives the cutter assembly in an oscillating manner. The probe also includes two or fewer seals within the housing in contact with the cutter assembly for sealing against fluid leakage.