SURGICAL INSTRUMENT RINGING A TITANIUM NEEDLE WITH A NODE OF MINIMUM AMPLITUDE IN A SUBSTANTIALLY CYLINDRICAL PORTION OF THE NEEDLE

• US 20130253557A1
• Filed: 03/26/2012
• Published: 09/26/2013
• Est. Priority Date: 03/26/2012
• Status: Active Grant

• Current Assignee: Johnson & Johnson Surgical Vision, Inc. (Johnson & Johnson)
• Original Assignee: Dana Companies, LLC
• Inventors: Urich, Alex, Maaskamp, Armand
• Granted Patent: US 9,216,035 B2
• Time in Patent Office: Days
• US Class Current: 606/169
• CPC Class Codes: A61B 17/3209 Incision instruments
• CPC Class Codes: A61B 2017/22018 segmented along its length
• CPC Class Codes: A61F 9/00745 using mechanical vibrations, e.g. ultrasonic

Abstract

A surgical instrument and method, for example to accomplish phacoemulsification, are disclosed. The surgical instrument includes a handpiece that has a piezoelectric transducer, and a titanium needle having a free distal tip and a supported end that is attached to the handpiece. The titanium needle has a substantially cylindrical portion with an outer diameter in the range 0.5 mm to 1.5 mm and a length in the range 12 mm to 37 mm. A circuit drives the piezoelectric transducer to periodically longitudinally expand and longitudinally contract at a driving frequency. The driving frequency is selected to ring the titanium needle with a standing wave that is characterized by longitudinal expansion and longitudinal contraction, the standing wave having a distal node of minimum amplitude in the substantially cylindrical portion.

Claims

1. A surgical instrument for phacoemulsification, the surgical instrument comprising:

a handpiece that includes a piezoelectric transducer;

a titanium needle having a free distal tip and a supported end that is attached to the handpiece, the titanium needle having a substantially cylindrical portion with an outer diameter in the range 0.5 mm to 1.5 mm and a length in the range 12 mm to 37 mm, the length being defined along a longitudinal axis of the titanium needle;

a circuit driving the piezoelectric transducer to periodically longitudinally expand and longitudinally contract at a driving frequency that rings the titanium needle with a standing wave that is characterized by longitudinal expansion and longitudinal contraction, the standing wave having a distal node of minimum amplitude in the substantially cylindrical portion.

2. The surgical instrument of claim 1 wherein the standing wave has a proximal node of minimum amplitude adjacent the supported end.

3. The surgical instrument of claim 1 wherein the standing wave has a distal anti-node of maximum amplitude at the free distal tip.

4. The surgical instrument of claim 1 wherein the distal node of minimum amplitude is disposed between 5 mm to 8 mm from the free distal tip.

5. The surgical instrument of claim 1 wherein the length is the range 13 mm to 38 mm, and the driving frequency is in the range 95 kHz to 290 kHz.

6. The surgical instrument of claim 5 wherein the length is approximately 17 mm, and the driving frequency is approximately 215 kHz.

7. The surgical instrument of claim 1 wherein the supported end includes external threads.

8. The surgical instrument of claim 1 wherein the substantially cylindrical portion includes a shoulder where the outer diameter changes, the outer diameter being less between the shoulder and the free distal tip than it is between the shoulder and the supported end.

9. The surgical instrument of claim 8 wherein the shoulder is disposed between 5 mm to 8 mm from the free distal tip.

10. The surgical instrument of claim 8 wherein the distal node is immediately adjacent the shoulder.

11. The surgical instrument of claim 1 wherein handpiece further includes a stainless steel back cylinder having back cylinder outer diameter in the range 9.5 mm to 13 mm.

12. The surgical instrument of claim 11 wherein the handpiece further includes a titanium front cylinder having front cylinder outer diameter in the range 3.5 mm to 6.5 mm, the piezoelectric transducer being disposed between the stainless steel back cylinder and the titanium front cylinder, the titanium needle being attached to the titanium front cylinder.

13. The surgical instrument of claim 1 wherein the piezoelectric transducer comprises a sandwich structure of two piezoelectric elements.

14. A method to drive oscillations in a surgical instrument, the method comprising:

attaching a supported end of a titanium needle to a handpiece that includes a piezoelectric transducer, the titanium needle having a free distal tip and a substantially cylindrical portion between the supported end and the free distal tip;

providing an oscillating voltage to the piezoelectric transducer in the handpiece, the voltage oscillating at a driving frequency that rings the titanium needle with a standing wave that is characterized by longitudinal expansion and longitudinal contraction, the standing wave having a distal node of minimum amplitude in the substantially cylindrical portion.

15. The method of claim 14 wherein the standing wave has a proximal node of minimum amplitude adjacent the supported end.

16. The method of claim 14 wherein the standing wave has a distal anti-node of maximum amplitude at the free distal tip.

17. The method of claim 14 wherein the distal node of minimum amplitude is disposed between 5 mm to 8 mm from the free distal tip.

18. The method of claim 14 wherein the substantially cylindrical portion has an annular cross-section with a circular outer periphery and a circular inner periphery, the circular outer periphery having a diameter in the range 0.5 mm to 1.5 mm.

19. The method of claim 14 wherein the substantially cylindrical portion has a length in the range 13 mm to 38 mm, and the driving frequency is in the range 95 kHz to 290 kHz.

20. The method of claim 19 wherein the length is approximately 17 mm, and the driving frequency is approximately 215 kHz.