Aspiration control system

• US 5,429,601 A
• Filed: 08/11/1993
• Issued: 07/04/1995
• Est. Priority Date: 02/12/1992
• Status: Expired due to Term

• Current Assignee: American Cyanamid Co (Pfizer Inc.)
• Original Assignee: American Cyanamid Co (Pfizer Inc.)
• Inventors: Appelbaum, Peter F., Williams, Daniel L. Jr., Conley, Paul G.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): MULCARE, NANCY C
• Application Number:
  US08/105,223
• Time in Patent Office: 692 Days
• Field of Search: 604/22, 604/26-28, 604/30, 604/31, 604/35, 604/65, 604/67, 604/73, 604/118, 604/119, 604/120, 604/121, 604/902, 606/107, 433/92
• US Class Current: 604/65
• CPC Class Codes: A61F 9/00736 Instruments for removal of intra-ocular material or intra-ocular injection, e.g. cataract instruments A61F9/008 takes precedence
• CPC Class Codes: A61M 1/74 Suction control underwater drainage A61M1/61
• CPC Class Codes: A61M 1/742 by changing the size of a vent A61M1/7411 takes precedence
• CPC Class Codes: A61M 1/743 by changing the cross-section of the line, e.g. flow regulating valves A61M1/7413 takes precedence
• CPC Class Codes: A61M 39/228 with a tubular diaphragm constrictable by radial fluid force

Abstract

An aspiration control system includes a proportional control valve and a motor, for driving a vacuum pump, which are controlled by a system controller in accordance with input commands to provide a precise, continuously variable vacuum or negative pressure within a vacuum chamber and surgical handpiece. A pressure transducer samples the vacuum output and produces a signal which is fed to the system controller. The signal is compared with an input command, and the motor speed and valve orifice size are coordinated to control the vacuum level.

Claims

1. A surgical aspiration control system for aspirating fluid and cut tissue from an operative site through a fluid conduit from a surgical handpiece into a vacuum chamber, the system comprising:

a vacuum pump for creating a negative pressure with the vacuum chamber, said vacuum pump being connectable in fluid communication to the vacuum chamber;

a motor mechanically coupled to said vacuum pump for operating said vacuum pump;

transducer means adapted for placement in pressure communication with the vacuum chamber, for sensing the vacuum within the vacuum chamber and for generating a first signal in response thereto;

a proportional control valve having an orifice which is variable in size and is disposed between a valve inlet and a valve outlet, said valve inlet communicatable with a fluid at a higher pressure than the pressure within the vacuum chamber, and said valve outlet being connectable in fluid communication to the vacuum chamber;

input means for selecting an appropriate vacuum level for aspirating and cutting tissue and for generating a second signal which corresponds to said appropriate level; and

controller means, connected to said transducer means and said input means, for comparing the first and second signals and for selectively regulating the rotational speed of said motor and the size of said orifice of said control valve to precisely control the vacuum level within the vacuum chamber and the surgical handpiece.

2. The surgical aspiration control system of claim 1 wherein said input means includes a foot pedal having a continuously variable range of angular position settings to enable selection of the appropriate vacuum level.

3. The surgical aspiration control system of claim 1 wherein said input means includes a console having at least one key to enable selection of the appropriate vacuum level.

4. The surgical aspiration control system of claim 1 wherein said control valve includes a diaphragm and spring acting on a needle pin such that as the vacuum level changes in the vacuum chamber, a corresponding change in atmospheric pressure across the diaphragm causes the needle pin to increase or decrease said orifice size.

5. The surgical aspiration control system of claim 1 wherein said control valve includes an electrically controllable valve member.

6. The surgical aspiration control system of claim 1 further including a pinch valve means installable on the fluid conduit between the vacuum chamber and the surgical handpiece to restrict the flow of fluid being aspirated by the surgical handpiece into the vacuum chamber in response to a command from said controller means.

7. The surgical aspiration control system of claim 6 wherein said pinch valve means comprises:

a positive pressure source;

a valve means having a diaphragm which in response to the positive pressure source restricts the effective area of the fluid conduit between the surgical handpiece and vacuum chamber; and

a flow regulator which regulates the amount of pressurized air provided from the positive pressure source to the diaphragm within the valve in response to the command from the controller means such that the fluid flow being aspirated through the surgical handpiece can be controlled independent of the vacuum level within the vacuum chamber.

8. The surgical aspiration control system of claim 1 wherein said motor is a brushless DC motor.

9. The surgical aspiration control system of claim 8 wherein said motor further comprises a motor controller having a PID type controller receiving a control signal from said controller means and sending a second control signal to said motor to precisely regulate the rotational speed and output of said motor and vacuum pump.

10. The surgical aspiration control system of claim 9 wherein said motor controller receives a feedback signal from said motor to precisely control the speed of said motor.

11. The surgical aspiration control system of claim 1 wherein said vacuum pump is a rotary vane vacuum pump.

12. The surgical aspiration control system of claim 1 further including a second conduit adapted to connect said vacuum pump to the vacuum chamber in fluid communication, and being further adapted to connect said valve outlet of said proportional control valve to the vacuum chamber in fluid communication.

13. The surgical aspiration control system of claim 12 further including the vacuum chamber, said vacuum chamber being removably connected to said second conduit.

14. The surgical aspiration control system of claim 13 wherein said vacuum chamber includes a removable cassette having rigid walls and a constant volume.

15. A surgical aspiration control system for aspirating fluid and cut tissue from an operative site through a fluid conduit from a surgical handpiece into a vacuum chamber, the system comprising:

a vacuum pump for creating a negative pressure within the vacuum chamber, said vacuum pump being connectable in fluid communication to the vacuum chamber;

a motor mechanically coupled to said vacuum pump for operating said vacuum pump;

transducer means adapted for placement in pressure communication with the vacuum chamber, for sensing the vacuum within the vacuum chamber and for generating a first signal in response thereto;

a proportional control valve having an orifice which is variable in size and is disposed between a valve inlet and a valve outlet, said valve inlet communicatable with a fluid at a higher pressure than the pressure within the vacuum chamber, and said valve outlet being connectable in fluid communication to the vacuum chamber;

a console having at least one key to enable selection of a maximum vacuum level;

a foot pedal having a continuously variable range of angular position settings to enable selection of an appropriate vacuum level, no greater than said maximum vacuum level, for aspirating and cutting tissue and for generating a second signal which corresponds to said appropriate level; and

controller means, connected to said transducer means and said input means, for comparing the first and second signals and for selectively regulating the rotational speed of said motor and the size of said orifice of said control valve to precisely control the vacuum level within the vacuum chamber and the surgical handpiece by driving a measured difference between the first and second signals toward zero.

16. The surgical aspiration control system of claim 15 further including a second conduit adapted to connect said vacuum pump to the vacuum chamber in fluid communication, and being further adapted to connect said valve outlet of said proportional control valve to the vacuum chamber in fluid communication.

17. The surgical aspiration control system of claim 16 further including the vacuum chamber, said vacuum chamber being removably connected to said second conduit.

18. The surgical aspiration control system of claim 17 wherein said vacuum chamber includes a removable cassette having rigid walls and a constant volume.

19. A method for controlling a surgical aspiration system for aspirating fluid and cut tissue from an operative site through a surgical handpiece into a vacuum chamber, comprising:

providing a proportional control valve having a variable orifice size, a vacuum pump, and a motor for driving the vacuum pump;

connecting the vacuum pump to the vacuum chamber for creating a negative pressure level within the vacuum chamber, the vacuum chamber being in fluid communication with the surgical handpiece;

connecting the control valve between the vacuum chamber and the vacuum pump;

producing a first signal corresponding to the negative pressure level within the vacuum chamber;

producing a second signal corresponding to the desired negative pressure within the vacuum chamber;

comparing the first and second signals; and

producing a third, control signal to selectively control the speed of the motor and a fourth, control signal to selectively control the orifice size of the control valve to regulate the negative pressure level within the vacuum chamber, the control signals corresponding to the comparison of the first and second signals.