Every Wednesday, we are going to start a new module to teach Phaco Fundamentals of machine parameters, including fluidics and ultrasonic power delivery. Understanding how to set up the phaco machine and tailor it to your surgical technique is critical to the success of cataract surgery. The topics will get progressively more detailed and complicated, but we will start with just the basics.
All phaco platforms share the same basic structure and concepts. The phaco machine aims to balance fluidics within the eye, while delivering ultrasonic energy and vacuum in order to emulsify and aspirate the cataract through a small incision.
Cataract surgery can be divided into multiple steps, each of which benefits from optimized fluidic settings. Let’s review the typical progression of steps:
- Pre-Phaco is a setting used to aspirate some of the anterior cortex within the confines of the capsulorhexis in order to provide better access to the nucleus. Low flow, low vacuum, and low phaco power are used.
- Sculpt is the setting used to create a groove or trench, using low flow, low vacuum and moderate phaco power, for techniques such as Divide-and-Conquer or Stop-and-Chop
- Chop settings have much higher vacuum to provide holding power on the nucleus so that the phaco chop technique can be used. Quadrant removal settings are similar but may have higher flow rates to bring the nuclear pieces to the phaco tip.
- Epinucleus settings are all about creating appropriate flow in the eye, which, along with moderate vacuum, can be used to aspirate the epi-nuclear shell
- Cortex setting is for use with the irrigation / aspiration probe where we want high vacuum and moderate flow to grab and remove lens cortical material
- Polish setting has low vacuum and low flow to help gently polish the capsular bag and in particular the posterior capsule with lower risk of iatrogenic damage
- Viscoleastic setting is to flush out and aspirate the viscoelastic from the eye at the end of the surgery so it has a high flow rate in addition to a high vacuum level
Note that all surgeons will not use all of these settings. For example. in my typical routine cataract, I use just three settings:
- Chop setting to break up and remove the lens nucleus
- Cortex setting to aspirate the lens cortical material
- Viscoelastic setting to flush out and remove any residual viscoelastic
Finally there are also settings which can be saved for unusual cases such as:
- coagulation which is a cautery mode to help with hemostasis
- anterior vitrectomy which is not used unless we have vitreous prolapse and capsular bag compromise
Click blow to learn from this video about phaco settings for steps of cataract surgery: