Micro-burst ultrasonic power delivery

• US 6,780,165 B2
• Filed: 02/26/2002
• Issued: 08/24/2004
• Est. Priority Date: 01/22/1997
• Status: Expired due to Term

• Current Assignee: Abbott Medical Optics Incorporated (Johnson & Johnson)
• Original Assignee: Advanced Medical Optics
• Inventors: Kadziauskas, Kenneth E., Rockley, Paul W., Staggs, James W.
• Primary Examiner(s): Casler, Brian L.
• Assistant Examiner(s): Kontos, Lina R
• Application Number:
  US10/085,508
• Publication Number:
  US 20020082793A1
• Time in Patent Office: 910 Days
• Field of Search: 604/22, 604/65, 606/107, 702/107
• US Class Current: 604/22
• CPC Class Codes: A61B 2017/0003 of parts of the instruments
• CPC Class Codes: A61B 2017/00106 ultrasonic
• CPC Class Codes: A61B 2017/00194 Means for setting or varying the repetition rate
• CPC Class Codes: A61B 2017/32007 with suction or vacuum means
• CPC Class Codes: A61B 2018/00636 Sensing and controlling the application of energy
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61F 9/007 Methods or devices for eye surgery
• CPC Class Codes: A61F 9/00745 using mechanical vibrations, e.g. ultrasonic
• CPC Class Codes: B06B 1/0246 with a feedback signal
• CPC Class Codes: B06B 1/0253 taken directly from the generator circuit
• CPC Class Codes: B06B 2201/55 Piezoelectric transducer
• CPC Class Codes: B06B 2201/76 Medical, dental

Abstract

Phacoemulsification apparatus includes a phacoemulsification handpiece having a needle and an electrical system for ultrasonically vibrating said needle along with a power source for providing pulsed electrical power to the handpiece electrical system. Irrigation fluid is provided to the handpiece needle and aspirating fluid is removed from the handpiece needle. A determination of a voltage current phase relationship of the provided electrical power is made and in response thereto a control system varies a power level duty cycle provided to the handpiece electrical system from the power source and/or modify the aspiration flow rate. In addition, a separate input enables manual control of pulse amplitude. The control system provides a pulsed electrical power of less than 20 millisecond pulse duration.

Claims

1. Phacoemulsification apparatus comprising:

a phacoemulsification handpiece having a needle and electrical means for ultrasonically vibrating said needle;

power source means for providing pulsed electrical power to the handpiece electrical means;

input means for enabling a surgeon to select an amplitude of the electrical pulses;

means for providing irrigation fluid to the eye and aspirating fluid from the handpiece needle; and

control means, for controlling a pulse duty cycle of power supplied to the handpiece, with a power pulse of less than 20 milliseconds.

2. The phacoemulsification apparatus according to claim 1 wherein said control means provides a pulse repetition rate of between about 25 and about 2000 pulses per second.

3. The phacoemulsification apparatus according to claim 1 wherein said input means enables a linear selection of pulse amplitude.

4. Phacoemulsification apparatus comprising:

a phacoemulsification handpiece having a needle and electrical means for ultrasonically vibrating said needle;

power source means for providing pulsed electrical power to the handpiece electrical means;

input means for enabling a surgeon to select an amplitude of the electrical pulses;

means for determining a voltage current phase relationship of the provided electrical power;

means for providing irrigation fluid to the eye and aspirating fluid from the handpiece needle; and

control means, responsive to the determined voltage current phase relationship, for controlling a pulse duty cycle, with a power pulse supplied to the handpiece of less than 20 milliseconds.

5. The phacoemulsification apparatus according to claim 4 wherein said control means provides a pulse repetition rate of between about 25 and about 2000 pulses per second.

6. The phacoemulsification apparatus according to claim 4 wherein said input means enables a linear selection of pulse amplitude.

7. The phacoemulsification apparatus according to claim 4 wherein the means for determining a voltage current phase relationship comprises:

means for obtaining an AC voltage signal corresponding to the operating AC voltage of a piezoelectric handpiece;

means for obtaining an AC current signal corresponding to the operating AC current of the piezoelectric handpiece;

means for determining onset of a current cycle from said AC current signal;

means for producing a voltage (V_I) corresponding to a time necessary for the AC current signal to reach a maximum value after onset of the current cycle;

means for producing a voltage (V_V) corresponding to a time necessary for the AC voltage signal to reach a maximum value after onset of the current cycle; and

A/D converter means for comparing (V_V) and (V_I) to determine the phase relationship between the voltage and current of the piezoelectric phacoemulsification handpiece and generating a phase signal (S_P) corresponding thereto, said phase signal being frequency independent.

8. A method for operating a phacoemulsification system, the system including a phacoemulsification handpiece, an ultrasonic power source, a vacuum source, a source of irrigating fluid, and a control unit for providing pulsed ultrasonic power to the handpiece, said operating method comprising the steps of:

(a) placing the handpiece in an operative relationship with an eye for a phacoemulsification procedure;

(b) supplying irrigation fluid from the irrigation fluid source into said eye;

(c) providing ultrasonic power from the ultrasonic power source to the handpiece of performing the phacoemulsification procedure;

(d) controlling an amplitude of power pulses provided to the handpiece;

(e) applying vacuum from the vacuum source to the handpiece and thereby aspirating the irrigation fluid from the eye through the handpiece at a selected rate;

(f) controlling a pulse duty cycle of power supplied to the handpiece, with a power pulse of less than 20 milliseconds.

9. The method according to claim 8 wherein the step of controlling the pulse duty cycle includes providing a pulse repetition rate of between about 25 and about 2000 pulses per second.

10. The method according to claim 8 wherein the step of controlling an amplitude of power pulse includes controlling the amplitude in a linear manner.

11. A method for operating a phacoemulsification system, the system including a phacoemulsification handpiece, an ultrasonic power source, a vacuum source, a source of irrigating fluid, and a control unit for providing pulsed ultrasonic power to the handpiece, said operating method comprising the steps of:

(a) placing the handpiece in an operative relationship with an eye for a phacoemulsification procedure;

(b) supplying irrigation fluid from the irrigation fluid source into said eye;

(c) providing ultrasonic power from the ultrasonic power source to the handpiece for performing the phacoemulsification procedure;

(d) controlling an amplitude of power pulses provided to the handpiece;

(e) determining a voltage current phase relationship of the power from the power source; and

(f) applying vacuum from the vacuum source to the handpiece and thereby aspirating the irrigating fluid from the eye through the handpiece at a selected rate;

(g) controlling, in response to the determined voltage current phase relationship, a pulse duty cycle of power supplied to the handpiece, with a power pulse of less than 20 milliseconds.

12. The method according to claim 11 wherein the step of controlling the pulse duty cycle includes providing a pulse repetition rate of between about 25 and about 2000 pulses per second.

13. The method according to claim 11 wherein the step of determining a voltage current phase relationship comprises the steps of:

obtaining an AC voltage signal corresponding to the operating AC voltage of a piezoelectric handpiece;

obtaining an AC current signal corresponding to the operating AC current of the piezoelectric handpiece;

from said AC current signal, determining onset of a current cycle;

after onset of the current cycle, producing a voltage (V_I) corresponding to a time necessary for the AC current signal to reach a maximum value;

after onset of the current cycle, producing a voltage (V_V) corresponding to a time necessary for the AC voltage signal to reach a maximum value; and

using an A/D converter, to produce a digital output signal, (S_P);

by comparing (V_V) to (V_I), and determining the phase relationship between the voltage and current of the piezoelectric phacoemulsification handpiece, said phase signal (S_P) being frequency independent.