Vitrectomy Probe Port Segmentation for Fluid Flow
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Solution Overview
Problem
Microsurgical cutting probes used in ophthalmic surgeries face challenges such as traction on the retina due to an annular space between cutting members, incomplete shearing of vitreous, and irregular dynamic shearing motion leading to wear and incarceration, as well as resistance to fluid flow through small orifices.
Innovation Solution
A vitrectomy probe design featuring an inner cutting member with a port having a guiding surface and side lobes that aligns with the outer cutting member's port, providing enhanced fluid flow and reducing sliding wear, along with an ovalized tip for better curvature match and smooth shearing, and side lobes to increase port size for improved fluid dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional cutting probe design with small orifices is used, then the device structure is simple, but fluid flow resistance increases and cutting efficiency decreases
Solution Approach 1:
The single port is segmented into multiple ports (first port and second port) arranged in a segmented pattern around the peripheral surface. This segmentation increases the total fluid flow area while maintaining a compact structure, reducing fluid flow resistance and improving cutting efficiency simultaneously
Solution Approach 2:
The ports are arranged in a segmented pattern around the peripheral surface, utilizing the circumferential dimension. This dimensional arrangement increases the effective port area without significantly increasing the probe diameter, allowing improved fluid flow while maintaining structural simplicity
2Ease of operation
If the inner cutting member is bent to bias the distal cutting surface toward the port, then shearing facilitation improves, but the inner cutting member protrudes too far causing irregular high-speed dynamic shearing motion and increased wear
Solution Approach 1:
The outer cutting member is provided with a guiding surface at a specific location (port region) that locally modifies the interaction between cutting members. This localized guiding surface controls the protrusion distance of the inner cutting member, enabling effective shearing while preventing excessive protrusion that would cause irregular motion and increased wear
3Device complexity
If an annular space exists between the outer cutting member and the inner cutting member, then the structure is simple, but traction is transmitted to the retina and vitreous incarceration occurs
Solution Approach 1:
The harmful annular space between the cutting members is eliminated by providing cutting surfaces on the outer cutting member that directly engage with the inner cutting member. This extraction of the harmful space prevents vitreous incarceration and retinal traction while maintaining structural simplicity through the integrated cutting surface design
Data Source
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AI summary
A vitrectomy probe includes a hand-graspable body and an outer tube extending from the hand-graspable body. The outer tube includes a closed distal end and a first port sized to receive 5 tissue. The vitrectomy probe also includes an inner tube within the outer tube with a second port that is selectively alignable with a portion of the first port to allow fluid flow and uniquely sized to increase fluid flow. The inner tube includes a distal tip with a cutting edge on each of the distal and proximal sides of the tip. The distal tip has a smaller diameter than that of the inner 10 tube at a proximal side of the second port. The proximal side of the second port includes a guiding surface that slidably bears on an inner surface of the outer tube to prevent the distal tip from excessively protruding from the first port of the outer tube.