METHOD AND APPARATUS FOR DETERMINING PARAMETERS OF LINEAR MOTION IN A SURGICAL INSTRUMENT

• US 20110204119A1
• Filed: 02/24/2011
• Published: 08/25/2011
• Est. Priority Date: 10/05/2007
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Tyco Healthcare Group LP (Medtronic Plc)
• Inventors: McCuen, David M.
• Granted Patent: US 8,960,520 B2
• Time in Patent Office: Days
• US Class Current: 227/175.1
• CPC Class Codes: A61B 17/068 Surgical staplers , e.g. containing multiple staples or clampsstaplers containing only one staple A61B17/10; magazines or containers for staples A61B17/105; for performing anastomosis A61B17/115; staplers in general B25C5/00
• CPC Class Codes: A61B 17/07207 the staples being applied sequentially
• CPC Class Codes: A61B 2017/00017 Electrical control of surgical instruments
• CPC Class Codes: A61B 2017/00367 Details of actuation of instruments, e.g. relations between pushing buttons, or the like, and activation of the tool, working tip, or the like
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: A61B 2090/067 for measuring angles

Abstract

A surgical instrument and method of controlling the surgical instrument are disclosed. The surgical instrument includes a housing and an elongated shaft that extends distally from the housing and defines a first longitudinal axis. The surgical instrument also includes a firing rod disposed in the elongated shaft and a drive mechanism disposed at least partially within the housing. The drive mechanism mechanically cooperates with the firing rod to move the firing rod. A motion sensor senses a change in the electric field (e.g., capacitance, impedance, or admittance) between the firing rod and the elongated shaft. The measurement unit determines a parameter of the motion of the firing rod, such as the position, speed, and direction of the firing rod, based on the sensed change in the electric field. A controller uses the measured parameter of the motion of the firing rod to control the drive mechanism.

Claims

1. A surgical instrument, comprising:

a housing;

an elongated shaft extending distally from the housing and defining a first longitudinal axis;

a firing rod disposed within the elongated shaft;

a drive mechanism disposed at least partially within the elongated shaft, the drive mechanism in mechanical cooperation with the firing rod;

a motion sensor that senses a change in the electric field between the firing rod and the elongated shaft; and

a measurement unit that determines a parameter of the motion of the firing rod based on a sensed change in the electric field.

2. The surgical instrument according to claim 1, wherein the motion sensor comprises a signal generator that generates a pulse signal that varies with the change in the electric field between the firing rod and the elongated shaft, the measurement unit determining a parameter of the motion of the firing rod based on the pulse signal.

3. The surgical instrument according to claim 2, wherein the measurement unit includes a counter that counts pulses in the pulse signal and a data processor that computes a pulse signal frequency and determines the parameter of the motion of the firing rod based on the pulse signal frequency.

4. The surgical instrument according to claim 1, wherein the parameter of the motion of the firing rod is the position of the firing rod.

5. The surgical instrument according to claim 1, wherein the parameter of the motion of the firing rod is the velocity of the firing rod.

6. The surgical instrument according to claim 1, wherein the parameter of the motion of the firing rod is the direction of motion of the firing rod.

7. The surgical instrument according to claim 1, wherein the drive mechanism is a drive motor, further comprising:

a controller that controls the drive motor based on the measured parameter of the motion of the firing rod.

8. The surgical instrument according to claim 1, further comprising:

a voltage source that applies a voltage to the firing rod.

9. The surgical instrument according to claim 1, further comprising:

a voltage source that applies a time-varying voltage to the firing rod.

10. A method of determining a parameter of the motion of a firing rod in a surgical instrument, comprising:

sensing a change in the electric field between a housing portion of a surgical instrument and a firing rod disposed in the housing portion; and

determining a parameter of the motion of the firing rod based on the sensed change in the electric field.

11. A method of operating a surgical instrument, comprising:

sensing a change in the electric field between a housing portion of a surgical instrument and a firing rod disposed in the housing;

determining a parameter of the motion of the firing rod based on the sensed change in the electric field; and

controlling the motion of the firing rod based on the determined parameter of the motion of the firing rod.

12. The method according to claim 11, wherein sensing a change in the electric field comprises generating a signal having a parameter that varies with the change in the electric field, and wherein determining the parameter of the motion of the firing rod comprises determining the parameter of the motion of the firing rod based on a parameter of the signal.

13. The method according to claim 12, wherein the parameter of the signal is the frequency of the signal, and wherein sensing a change in the electric field further comprises counting pulses of the signal over a predetermined time period and computing a signal frequency based on the counted pulses and the predetermined time period.

14. The method according to claim 11, wherein the parameter of the signal is the width of the pulses in the signal, and wherein sensing a change in the electric field further includes determining the width of the pulses of the signal.

15. The method according to claim 11, wherein the parameter of the motion of the firing rod is the position of the firing rod.

16. The method according to claim 11, wherein the parameter of the motion of the firing rod is the velocity of the firing rod.

17. The method according to claim 11, wherein the parameter of the motion of the firing rod is the direction of the firing rod.

18. The method according to claim 17, wherein determining the direction of the firing rod comprises determining an increase or decrease in the frequency of a signal that varies with the change in the electric field.

19. The method according to claim 11, further comprising:

applying an electric potential to the firing rod.

20. The method according to claim 11, further comprising:

applying a time-varying electric potential to the firing rod.