Vacuum sense control for phaco pulse shaping
View Patent ↗A method and apparatus for precisely controlling particle movement relative to a phacoemulsification needle tip is provided. The design monitors actual vacuum present and calculates a pulse shape amplitude waveform proportional to the amount of measured vacuum. An increase in vacuum indicates that the handpiece/needle is becoming occluded by a large particle. The present design determines whether additional power is required to bump or move a large particle away from the needle tip. The present design may employ a control loop that senses and continuously monitors vacuum. The design may dynamically vary the amount of ultrasonic energy delivered to the surgical area in response to the observed actual vacuum, and can actively vary the amount of power delivered to the surgical area based on the size of the particle and the resultant vacuum realized.
1. An apparatus for controlling ultrasonic power delivery to a surgical area, comprising:
a device configured to encounter vacuum pressure at the surgical area;
a vacuum sensor configured to monitor vacuum pressure encountered by said device;
a computer configured to compute an ultrasonic pulse profile for delivery to a needle configured to vibrate based on the ultrasonic pulse profile received, the ultrasonic pulse profile based on monitored vacuum pressure received from the vacuum sensor;
wherein the ultrasonic pulse profile comprises a baseline ultrasonic pulse region and an altered ultrasonic pulse region, the altered ultrasonic pulse region comprising a pulse portion altered based on monitored vacuum pressure; and
wherein the computer computes the ultrasonic pulse profile based on actual sensed aspiration vacuum pressure multiplied by maximum pulse amplitude minus minimum pulse amplitude and divided by maximum sensed aspiration vacuum pressure, added to minimum pulse amplitude.
2. The apparatus of claim 1 , wherein the device comprises the needle.
3. The apparatus of claim 1 , wherein the needle is within a second device.
4. The apparatus of claim 1 , wherein the computer delivers the ultrasonic pulse profile to the needle and movement of the needle induces transient cavitation within fluid within the surgical area.
5. The apparatus of claim 1 , wherein the computer computes and applies multiple pulses to the needle, the multiple pulses each comprising an individual pulse shape formed based on actual sensed aspiration vacuum pressure.