Device and method for controlling compression of tissue

• US 8,012,170 B2
• Filed: 04/27/2009
• Issued: 09/06/2011
• Est. Priority Date: 04/27/2009
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Tyco Healthcare Group LP (Medtronic Plc)
• Inventors: Whitman, Michael P., Malinouskas, Donald, Zeichner, David A.
• Primary Examiner(s): Smith; Scott A.
• Application Number:
  US12/430,780
• Publication Number:
  US 20100270355A1
• Time in Patent Office: 862 Days
• Field of Search: 227/19, 227/175.1, 227/176.1, 227/175.2, 227/180.1, 606/151, 606/153, 606/219
• US Class Current: 606/219
• 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 17/0686 having a forming anvil staying below the tissue during stapling
• CPC Class Codes: A61B 17/072 for applying a row of staples in a single action , e.g. the staples being applied simultaneously
• CPC Class Codes: A61B 17/07207 the staples being applied sequentially
• CPC Class Codes: A61B 17/08 Wound clamps or clips, i.e. not or only partly penetrating the tissue suture bridges A61B17/0466; Devices for bringing together the edges of a wound
• CPC Class Codes: A61B 17/1114 of the digestive tract, e.g. bowels or oesophagus
• CPC Class Codes: A61B 17/115 Staplers for performing anastomosis in a single operation
• CPC Class Codes: A61B 2017/00017 Electrical control of surgical instruments
• CPC Class Codes: A61B 2017/00022 Sensing or detecting at the treatment site
• CPC Class Codes: A61B 2017/00119 alarm; indicating an abnormal situation
• CPC Class Codes: A61B 2017/00123 and automatic shutdown
• CPC Class Codes: A61B 2017/00398 using powered actuators, e.g. stepper motors, solenoids
• CPC Class Codes: A61B 2017/07214 Stapler heads
• CPC Class Codes: A61B 2017/2927 the angular position of the head being adjustable with respect to the shaft
• CPC Class Codes: A61B 2017/2943 Toothed members, e.g. rack and pinion
• CPC Class Codes: A61B 2090/032 pressure limiting, e.g. hydrostatic
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 2090/0803 Counting the number of times an instrument is used
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 34/76 Manipulators having means for providing feel, e.g. force or tactile feedback

Abstract

A method and device for controlling the compression of tissue include clamping tissue between a first clamping member and a second clamping member by driving at least one of the clamping members with an electric motor toward a predetermined tissue gap between the clamping members and, during the clamping, monitoring a parameter of the electric motor indicative of a clamping force exerted to the tissue by the clamping members. The method and device include, during the clamping, controlling the electric motor, based on the monitored parameter, to limit the clamping force to a predetermined maximum limit.

Claims

1. A method, comprising:

clamping tissue between a first clamping member and a second clamping member by driving at least one of the clamping members with an electric motor toward a predetermined tissue gap between the clamping members;

during the clamping, monitoring a parameter of the electric motor indicative of a clamping force exerted to the tissue by the clamping members; and

during the clamping, controlling the electric motor, based on the monitored parameter, to limit the clamping force to a predetermined maximum limit.

2. The method of claim 1, wherein the predetermined maximum limit is selected based on predetermined properties of the tissue to be clamped.

3. The method of claim 2, wherein the predetermined maximum limit is selected to limit trauma to the clamped tissue to a predetermined acceptable level.

4. The method of claim 1, wherein the predetermined maximum limit is below a predetermined deflection limit of the at least one of the clamping members.

5. The method of claim 1, wherein the controlling includes adjusting a voltage applied to the electric motor.

6. The method of claim 1, wherein the controlling includes limiting the current driving the electric motor.

7. The method of claim 1, wherein the monitoring includes measuring a current driving the electric motor.

8. The method of claim 7, further comprising:

prior to the clamping, measuring current due to frictional losses associated with moving the clamping members; and

subtracting the frictional losses from the current measured during the clamping.

9. The method of claim 7, further comprising, prior to the clamping, measuring a current offset.

10. The method of claim 9, further comprising subtracting the current offset from the current measured during the clamping.

11. The method of claim 1, wherein the predetermined maximum limit is selected to prevent the force from reaching a yield force.

12. The method of claim 1, wherein the predetermined maximum limit is selected to prevent the clamping members from splaying.

13. The method of claim 1, further comprising using a profile of the monitored parameter to monitor and track structural fatigue in at least one of the clamping members.

14. The method of claim 13, wherein the profile is compared to a normal parameter signature.

15. The method of claim 1, wherein the surgical instrument is a surgical stapler and one of the clamping members is an anvil configured to form surgical staples.

16. The method of claim 15, further comprising using a profile of the monitored parameter to identify whether all of the staples of a staple cartridge have fired.

17. The method of claim 15, further comprising using a profile of the monitored parameter to identify at least one of staple misfires, an absence of staples in a staple cartridge, and staple jams.

18. The method of claim 1, wherein the controlling includes:

determining a motor velocity;

determining a motor position; and

determining a net motor current attributable to the compression by subtracting out a current offset and current due to frictional losses.

19. The method of claim 18, wherein the controlling further comprises:

determining a velocity drive based on the determined velocity;

determining a position drive based on the determined position; and

determining a current drive based on the determined net motor current.

20. The method of claim 19, wherein the controlling further comprises applying the smallest of the velocity drive, the position drive, and the current drive to the motor.

21. The method of claim 18, further comprising detecting the presence of an incompressible object based on the motor velocity.

22. The method of claim 1, wherein the controlling includes adjusting a driving speed of the motor to limit the clamping force to the predetermined maximum limit.