High speed vitreous cutting system

• US 6,575,990 B1
• Filed: 10/20/2000
• Issued: 06/10/2003
• Est. Priority Date: 10/21/1999
• Status: Active Grant

• Current Assignee: Medical Instrument Development Laboratories, Inc.
• Original Assignee: Medical Instrument Development Laboratories, Inc.
• Inventors: Wang, Carl C., Peterson, Erik W.
• Primary Examiner(s): Truong, Kevin T.
• Assistant Examiner(s): NGUYEN, VI X
• Application Number:
  US09/693,107
• Time in Patent Office: 963 Days
• Field of Search: 137/102, 604/22, 604/143, 606/167, 606/170, 606/171
• US Class Current: 606/171
• CPC Class Codes: A61B 17/32002 with continuously rotating, oscillating or reciprocating cutting instruments
• CPC Class Codes: A61B 2017/00159 Pulse shapes
• CPC Class Codes: A61B 2017/00172 Pulse trains, bursts, intermittent continuous operation
• CPC Class Codes: A61B 2017/00181 Means for setting or varying the pulse energy
• CPC Class Codes: A61B 2017/0019 Means for setting or varying the pulse width
• CPC Class Codes: A61B 2017/00544 pneumatically
• CPC Class Codes: A61F 9/00763 with rotating or reciprocating cutting elements, e.g. concentric cutting needles atherectomy cutting instruments A61B17/3207; endoscopic cutting instruments A61B17/320016

Abstract

A high-speed pneumatic cutting system having a cutter and an actuator. The cutter is a guillotine-type, pneumatic cutter that receives a train of pressure pulses from the actuator. The actuator is designed to capture pressure pulses it receives from a pneumatic energy source in a surgical machine, such as a vitrectomy machine, or to generate its own pneumatic energy. The actuator has an accumulator coupled to the outlet of the pneumatic energy and a pressure transducer that senses the pressure level inside the accumulator. A control and display unit with a plurality of input mechanisms receives inputs from a user who selects a desired cutting rate or frequency for the cutter. The control and display unit produces an output signal based on the inputs received. The outputs from the control and display unit and the pressure transducer are sent to a waveform shaping circuit. The waveform shaping circuit produces a command signal based on the inputs that it receives. The command signal is delivered to a valve that is coupled in fluid communication to the accumulator. The valve is opened and closed according to the command signal to produce a pulse train that will operate the cutter at the selected cutting rate. The actuator may be designed as a stand-alone unit or may be integrated into a surgical machine.

Claims

1. A pneumatic surgical cutting system comprising:

a surgical machine operable to produce a first pneumatic output;

an actuator coupled to the surgical machine, the actuator including;

a first accumulator coupled to the surgical machine through a one-way valve to receive the first pneumatic output;

a waveform control operable to control the width of a pressure pulse, coupled to the first accumulator, and activated when the surgical machine produces the first pneumatic output;

a pressure regulator having an input and an output, the input being coupled to the first accumulator;

a second accumulator coupled to the output of the pressure regulator; and

a valve coupled to the second accumulator and the waveform control;

a surgical cutter coupled to the valve by a tubing.

2. A system as in claim 1, wherein the valve outputs a pressure pulse train.

3. A system as in claim 2, wherein the pressure pulse train has a variable pulse width.

4. A system as in claim 3, wherein the waveform control controls the pulse width of the pressure pulse train as a function of a desired frequency.

5. A pneumatic surgical cutting system comprising:

a surgical machine operable to produce a first pneumatic output;

an actuator coupled to the surgical machine, the actuator including;

a first accumulator coupled to the surgical machine through a one-way valve to receive the first pneumatic output;

a waveform control coupled to the first accumulator and activated when the surgical machine produces the first pneumatic output;

a pressure regulator having an input and an output, the input being coupled to the first accumulator;

a second accumulator coupled to the output of the pressure regulator; and

a valve coupled to the second accumulator and the waveform control, the valve outputting a pressure pulse train having a variable pulse width, and wherein the waveform control controls the pulse width of the pressure pulse train as a function of a desired frequency;

a surgical cutter coupled to the actuator valve by a tubing; and

a pressure sensor for sensing the pressure in the second accumulator.

6. A system as in claim 5, wherein the waveform control controls the pulse width of the pressure pulse train as a function of a desired frequency and the pressure of the second accumulator.

7. A pneumatic surgical cutting system comprising:

a surgical machine operable to produce a first output;

an actuator coupled to the surgical machine, the actuator including

a waveform control coupled to the surgical machine and activated when the surgical machine produces the first output;

a compressor having a pneumatic input and a pneumatic output;

an accumulator coupled to the compressor to receive the pneumatic output;

a pressure sensor for sensing the pressure in the accumulator; and

a valve coupled to the accumulator and the waveform control; and

a surgical cutter coupled to the valve by a tubing.

8. A system as in claim 7, wherein the valve outputs a pressure waveform.

9. A system as in claim 8, wherein the pressure waveform has a variable pulse width.

10. A system as in claim 9, wherein the waveform control controls the pulse width of the pressure waveform as a function of a desired frequency and the pressure of the accumulator.

11. A system as in claim 7, further comprising a control and display device coupled to the waveform control, the control and display device having a plurality of input mechanisms and producing an output signal based on the inputs received through the input mechanisms.

12. A system as in claim 7, wherein said first output is pneumatic.

13. A system as in claim 7, wherein said first output is electrical.

14. A system as in claim 7, further comprising a controller coupled to the compressor and the pressure sensor, the controller operable to supply power to the compressor at a rate that is a function of the difference between the pressure in the accumulator and a predetermined pressure.

15. A pneumatic surgical cutting system comprising:

a surgical machine operable to produce a first output;

an actuator coupled to the surgical machine, the actuator including

a waveform control coupled to the surgical machine and activated when the surgical machine produces the first output;

a compressor having a pneumatic input and a pneumatic output;

an accumulator coupled to the compressor to receive the pneumatic output;

a pressure sensor for sensing the pressure in the accumulator; and

a valve coupled to the accumulator and the waveform control;

a surgical cutter coupled to the valve by a tubing;

a second accumulator;

a connection between the second accumulator and the valve;

a connection between the second accumulator and the pneumatic input of the compressor; and

a connection between the second accumulator and the atmosphere.

16. A system as in claim 15, wherein said connection between the second accumulator and the atmosphere includes a sound-absorber.

17. A system as in claim 15, wherein the valve is arranged such that the surgical cutter is alternately coupled to either the first accumulator or the second accumulator.

18. A surgical cutter assembly comprising:

a tubular outer member, being substantially rigid, having a proximal end and a distal end;

a cutting port, having a cutting edge, disposed near the distal end of the tubular outer member;

a tubular inner member, being substantially resilient, having a proximal end and a distal end, having an outer radius substantially less than the inner radius of said tubular outer member, wherein the distal end the tubular inner member is circularly flared to an outer radius which approximates the inner radius of said tubular outer member and wherein a cutting edge is formed on the distal end of the tubular inner member, said tubular inner member being disposed approximately coaxially within said tubular outer member;

driving means coupled to the proximal end of said inner member, operable to impart an axial reciprocating motion to said inner member; and

a housing coupled to the proximal end of said outer member, wherein said driving means and tubular inner member are disposed in a fixed relationship to said tubular outer member;

said surgical cutter assembly having constructional features that cause the cutting edge of the tubular inner member to be resiliently biased against the inner surface of the tubular outer member along the side wherein the cutting port is disposed.

19. A surgical cutter assembly as in claim 18, wherein said constructional features include a bend in said tubular inner member.

20. A surgical cutter assembly as in claim 19, wherein said driving means is operable by pneumatic pressure.

21. A surgical cutter assembly as in claim 20, wherein said driving means is operable by a pneumatic pressure of approximately 13 psi or less.

22. A surgical cutter assembly as in claim 20, wherein said tubular inner member has a wall thickness of between 0.002 inches and 0.003 inches.

23. A surgical cutter assembly as in claim 19, wherein said tubular inner member has a wall thickness of between 0.002 inches and 0.003 inches.

24. A surgical cutter assembly as in claim 18, wherein said constructional features include a bend in said tubular outer member.

25. A surgical cutter assembly as in claim 18, wherein said driving means is operable by pneumatic pressure.

26. A surgical cutter assembly as in claim 25, wherein said driving means is operable by a pneumatic pressure of approximately 13 psi or less.

27. A surgical cutter assembly as in claim 18, wherein said tubular inner member has a wall thickness of between 0.002 inches and 0.003 inches.

28. A cutting system comprising:

an actuator providing a pressure pulse train having a variable pulse width, the actuator having

a pressure source having a real-time pressure; and

a waveform control that controls the pulse width of the pressure pulse train as a function of the desired frequency and the real-time pressure of the pressure source;

a pneumatically operated cutter assembly having

a tubular outer member having a distal end, an inner radius, an outer radius and an inner surface, wherein a cutting port is disposed on a side of the tubular outer member near the distal end; and

a resilient tubular inner member having a distal end and having an outer radius substantially less than the inner radius of the tubular outer member, wherein the distal end is flared to an outer radius which approximates the inner radius of said outer member and wherein a cutting edge is formed on the distal end, said tubular inner member being bent so as to resiliently bias the cutting edge of the tubular inner member against the inner surface of the tubular outer member along the side wherein the cutting port is disposed; and

a tubing disposed between the actuator and the cutter assembly.

29. A cutting system as in claim 28, wherein the pulse width of the pressure pulse train is controlled such that the peak pressure of the pressure waveform at the juncture of the tubing with the cutter is at a predetermined level.

30. A cutting system as in claim 29, wherein said predetermined level is at or slightly above the level necessary to operate the cutter.

31. A cutting system as in claim 30, wherein said predetermined level is about 13 psi or less.

32. A cutting system as in claim 30, wherein the minimum pressure of the pressure waveform at the juncture of the tubing with the cutter is no greater than the pressure level necessary to permit the cutter blade to retract, when the frequency of the pressure pulse train is 900 pulses per minute or less.

33. A cutting system as in claim 30, wherein the minimum pressure of the pressure waveform at the juncture of the tubing with the cutter is no greater than the pressure level necessary to permit the cutter blade to retract, when the frequency of the pressure pulse train is 1500 pulses per minute or less.

34. A surgical cutter assembly comprising:

a tubular outer member, being substantially rigid, having a proximal end and a distal end;

a cutting port, having a cutting edge, disposed near the distal end of the tubular outer member;

a tubular inner member, being substantially resilient, having a proximal end and a distal end, having an outer radius substantially less than the inner radius of said tubular outer member, wherein the distal end is flared to an outer radius which approximates the inner radius of said tubular outer member and wherein a cutting edge is formed on the distal end, said tubular inner member being disposed approximately coaxially within said tubular outer member;

pneumatically operated driving means coupled to the proximal end of said inner member, operable to impart an axial reciprocating motion to said inner member, said means being operable by a pneumatic pressure of approximately 13 psi or less; and

a housing coupled to the proximal end of said outer member, wherein said driving means and inner member are disposed in a fixed relationship to said outer member;

said surgical cutter assembly having constructional features, which cause the cutting edge of the tubular inner member to be resiliently biased against the inner surface of the tubular outer member along the side wherein the cutting port is disposed.

35. A surgical cutter assembly as in claim 34, wherein said constructional features comprise a bend in said tubular inner member.

36. A surgical cutter assembly as in claim 34, wherein said constructional features comprise a bend in said tubular outer member.

37. A surgical cutter assembly as in claim 34, wherein said tubular inner member has a wall thickness of between 0.002 inches and 0.003 inches.