Oscillating Vitrectomy Probe for Precise Retinal-Side Cutting
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Solution Overview
Problem
Microsurgical procedures, particularly those involving the cutting and removal of vitreous humor in the eye, face challenges in avoiding traction on the retina and retinal tears due to the delicate nature of the vitreous fibrils attached to the retina.
Innovation Solution
A vitrectomy probe design featuring an outer cutting tube and an inner cutting tube with a diaphragm-driven oscillation mechanism, utilizing pneumatic pressure to alternately extend and retract the inner cutting tube across the outer tube's port, enabling precise cutting and aspiration of vitreous humor, with materials entering the port being cut by distal and proximal cutting edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a traditional vitrectomy probe with a fixed cutting tube is used, then the structure is simple and easy to manufacture, but the cutting precision and control over vitreous removal near the retina are insufficient
Solution Approach 1:
The patent applies the dynamics principle by making the inner cutting tube movable rather than fixed. The inner cutting tube can oscillate back and forth within the outer cutting tube, allowing dynamic adjustment of the cutting position and depth. This dynamic mechanism enables precise control over vitreous cutting near the retina while managing the complexity through a relatively simple oscillation drive system.
Solution Approach 2:
The patent segments the cutting function by separating it into two independent cutting tubes (inner and outer), each with its own cutting edge. This segmentation allows the inner tube to perform precise cutting actions while the outer tube provides structural support and aspiration. The segmented design enables independent control of cutting and aspiration functions, improving precision without excessive complexity.
2Productivity
If the inner cutting tube extends fully to maximize cutting depth, then cutting capability is improved, but the risk of retinal traction and tears increases
Solution Approach 1:
The oscillating inner cutting tube allows the cutting edge to dynamically adjust its position relative to the retinal surface. During the retraction phase of oscillation, the cutting edge moves away from the retina, minimizing traction and tear risk. During the extension phase, precise cutting is achieved. This dynamic motion pattern enables effective cutting while protecting the retina from harmful traction forces.
Solution Approach 2:
The periodic oscillation of the inner cutting tube creates alternating phases of extension (cutting) and retraction (release). This periodic action ensures that the cutting edge does not remain in continuous contact with the retina, thereby preventing sustained traction that could cause tears. The rhythmic motion pattern balances cutting effectiveness with retinal safety.
3Measurement precision
If a flat-ended vitrectomy probe is used, then the port to tip distance is minimized for precise positioning, but the cutting action may cause more traction on attached vitreous fibrils
Solution Approach 1:
The oscillating inner cutting tube compensates for the minimal port-to-tip distance by creating dynamic cutting motion. The back-and-forth movement allows the cutting edge to engage and disengage from the vitreous fibrils in a controlled manner, reducing sustained traction on attached fibrils while maintaining precise positioning capability near the retina.
Solution Approach 2:
The oscillation of the inner cutting tube introduces mechanical vibration to the cutting process. This vibration helps to minimize adhesion between the cutting edge and the vitreous fibrils, reducing traction forces on attached fibrils. The vibrational motion allows for cleaner cutting with less resistance, thereby reducing harmful traction effects while maintaining precise positioning.
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
The probe achieves precise cutting and aspiration of vitreous humor near the retina, minimizing the risk of retinal traction and tears by allowing controlled cutting and removal of vitreous humor with reduced mechanical stress on the retina.
Implementation Method 1
The diaphragm moves back and forth inside the drive chamber as air is alternately supplied (by a pneumatic drive line) and vented on either side of the diaphragm
Implementation Method 2
the cut tissue may then be aspirated away through the inner cutting member
Data Source
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AI summary
In some embodiments, a vitrectomy probe may include an inner cutting tube reciprocating in an outer tube. The outer tube includes a side port and the inner tube includes a distal cutting port, and, in some embodiments, an additional side port. In some embodiments, the inner tube may also include a flat upper edge that cuts across the outer tube side port. In some embodiments, a diaphragm drives the inner tube and may have an open-stroke side with a lower hardness material than a closed-stroke side. In some embodiments, an aspiration tube coupled to the vitrectomy probe may include a first aspiration tubing and a second aspiration tubing with a lower hardness than the first aspiration tubing. In some embodiments, the vitrectomy probe may be coupled to pneumatic tubing that is stepped or tapered.