Vitrectomy Probe Rotary Cutter Pneumatic Actuator
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Solution Overview
Problem
Conventional vitrectomy probes face challenges in cutting and removing vitreous humor without causing traction on the retina or tearing of vitreous collagen fibers, with axial probes experiencing pulsatile flow and rotational probes risking winding due to continuous rotation.
Innovation Solution
A vitrectomy probe with a pneumatic vane actuator that rotates a inner cutting member in limited rotary action, using alternating air pressure pulses and vacuum pulses to drive the cutting member in opposite directions, reducing pulsatile flow and winding, and featuring a rotational blade with two cutting surfaces for improved cutting capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous rotation of the inner cutting member is used in rotational probes, then cutting capacity is improved, but winding and tearing of vitreous collagen fibers occurs
Solution Approach 1:
The patent applies periodic reciprocating rotation to the inner cutting member instead of continuous rotation. The cutting member rotates in one direction to cut tissue, then reverses direction to return to its starting position without cutting. This periodic action maintains high cutting capacity while preventing the continuous winding and tearing of vitreous collagen fibers that occurs with uninterrupted rotation.
Solution Approach 2:
The patent implements dynamic control of the inner cutting member's rotation, allowing it to alternate between rotating in a first direction to cut tissue and rotating in a second opposite direction to return to the starting position. This dynamic reciprocating motion optimizes cutting performance while minimizing harmful winding effects on the vitreous humor.
2Ease of operation
If axial or guillotine style probe with reciprocating inner cutting member is used, then cutting function is achieved, but pulsatile flow pushing fluid out of port occurs
Solution Approach 1:
The patent replaces the traditional axial reciprocating mechanical cutting system with a rotational cutting mechanism. Instead of the inner cutting member moving linearly back and forth through the outer cutting member, it rotates reciprocally, which eliminates the pumping action that causes pulsatile fluid flow while maintaining effective tissue cutting capability.
3Object-generated harmful factors
If limited rotary action drive mechanisms are used to address continuous rotation issues, then winding is reduced, but spiral torsional failure occurs in small gauge probes
Solution Approach 1:
The patent employs periodic reciprocating rotation where the inner cutting member rotates in one direction to cut tissue, then reverses to return to its starting position. This limited rotary action with regular reversal prevents accumulation of torsional stress that would lead to spiral failure, while still achieving effective cutting through the reciprocating motion.
Solution Approach 2:
The patent implements dynamic reciprocating rotation that adapts to the small gauge constraints. The inner cutting member dynamically alternates between cutting rotation and return rotation, preventing excessive torsional buildup that would cause failure while maintaining cutting effectiveness throughout the procedure.
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 solution effectively minimizes pulsatile flow and winding, enhances cutting capacity, and allows for scalability across various gauge sizes, reducing the likelihood of spiral torsional failures, thereby improving the precision and efficiency of vitreous humor removal during ophthalmic surgeries.
Implementation Method 1
The pneumatic vane actuator may be configured to rotate the inner cutting member... by applying air pressure pulses to a pneumatic vane actuator disposed in the vitrectomy probe
Implementation Method 2
rotating the inner cutting member to cut tissue in the outer port by applying air pressure pulses to a pneumatic vane actuator disposed in the vitrectomy probe
Data Source
Figure 1~2
Figure 3
Figure 4A~5B
AI summary
Systems, apparatuses, and methods of and for an ophthalmic surgical system are disclosed. An ophthalmic surgical system may include a vitrectomy probe having a housing sized and shaped for grasping by a user. The vitrectomy probe may also include a cutter extending from the housing and being sized to penetrate and treat a patient eye. The cutter may include an outer cutting tube coupled to the housing. The outer cutting tube may have an outer port formed therein that is sized and shaped to receive tissue. The cutter may include a rotatable inner cutting member disposed within the outer cutting tube. The inner cutting member may include a first cutting surface that rotates across the outer port to cut the tissue when the inner cutting member is rotated. The vitrectomy probe may include a pneumatic vane actuator positioned within the housing and configured to rotate the inner cutting member.