Multi-stage Trigger Cam Assembly for Ophthalmic Tool Surge Control
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Solution Overview
Problem
Conventional ophthalmic microsurgical tools face challenges with long, flexible suction lines that cause fluidic system compliance issues, leading to delayed responsive times and post-occlusion surge during phacoemulsification procedures.
Innovation Solution
A medical device with a cam assembly integrated within the hand-held housing, featuring a multi-stage trigger that controls vacuum generation and oscillation of the shaft, allowing for precise irrigation and aspiration phases, including irrigation-only, low-flow continuous aspiration, and pulsatile aspiration-plus-cutting modes, to improve responsiveness and reduce surge volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a remote vacuum source with long flexible suction lines is used, then the device can be operated with a remote pump, but the fluidic system compliance increases causing delayed responsive times and post-occlusion surge
Solution Approach 1:
The device is divided into two functional segments: a handheld unit containing the vacuum source and cam assembly for direct control, and a separate console for monitoring and support functions. This segmentation allows the critical vacuum generation to be close to the tip while maintaining remote operation capabilities through the console connection.
Solution Approach 2:
A cam assembly acts as an intermediary mechanism between the trigger actuation and the vacuum generation system. The cam converts the linear trigger motion into rotational motion that directly drives the vacuum source, providing mechanical coupling that reduces compliance effects while maintaining ease of operation.
2Ease of operation
If a remote vacuum source with long flexible suction lines is used, then the device can be operated with a remote pump, but the fluidic system compliance increases causing post-occlusion surge
Solution Approach 1:
The cam assembly is pre-configured with asymmetric cam profiles that anticipate occlusion events. The cam geometry is designed to gradually reduce vacuum pressure before complete occlusion occurs, preventing the sudden pressure surge that would otherwise occur when the occlusion is released.
Solution Approach 2:
The vacuum generation system transitions from static remote pump operation to dynamic cam-driven vacuum with variable pressure control. The cam profile allows the vacuum pressure to dynamically adjust during the cutting cycle, reducing surge volume by modulating the vacuum strength in response to tissue engagement.
3Reliability
If a multi-stage trigger with cam assembly is used, then the responsive time and surge volume are reduced, but the device complexity increases
Solution Approach 1:
The cam assembly merges multiple functions into a single mechanical component: vacuum generation, oscillation control, and multi-stage trigger response. By combining these functions in one integrated cam structure, the patent reduces the number of separate components needed while achieving the desired responsive performance.
Solution Approach 2:
The cam assembly serves multiple purposes simultaneously: it generates vacuum through eccentric rotation, controls shaft oscillation through cam profile geometry, and enables multi-stage trigger functionality. This multi-functionality reduces overall device complexity by eliminating the need for separate mechanisms for each function.
4Reliability
If a multi-stage trigger with cam assembly is used, then the responsive time and surge volume are reduced, but the device complexity increases
Solution Approach 1:
The cam assembly creates periodic vacuum pulses through its rotating eccentric profile, which naturally limits surge volume by interrupting continuous vacuum application. This periodic action is achieved through simple rotational mechanics rather than complex control systems, managing surge volume while maintaining reasonable device complexity.
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 device enhances control and responsiveness during ophthalmic surgeries by minimizing fluidic system compliance and surge volume, allowing for efficient lens tissue fragmentation and removal with reduced fluid usage and improved surgical precision.
Implementation Method 1
the vacuum generation source to generate vacuum through the lumen
Implementation Method 2
aspiration to remove the lens emulsate from the eye
Implementation Method 3
phacoemulsification, which uses ultrasonic energy to emulsify the lens
Data Source
AI summary
A medical device for removing lens tissue from inside a capsular bag of an eye including a cam assembly operatively coupled to a vacuum generation source positioned within the housing. A first portion is operatively coupled to the vacuum generation source and a second portion is operatively coupled to the first portion and to the shaft. The first portion is capable of rotating about an axis to cause the vacuum generation source to generate vacuum through the lumen. The second portion is capable of rotating about the axis with the first portion to cause the shaft to oscillate. A first degree of actuation of a trigger causes the vacuum generation source to generate vacuum within the lumen of the shaft, and a second degree of actuation of the trigger causes the shaft to oscillate as the second portion rotates. Related systems, devices, and methods are provided.