Method of operating a powered surgical instrument

1. A method of operating a surgical instrument, the surgical instrument comprising an electric motor coupled to an end effector, a motor controller coupled to the motor, a parameter threshold detection module, a sensing module, a processor, and a memory coupled to the processor, the memory storing executable instructions that when executed by the processor cause the processor to execute the method, the method comprising:

monitoring multiple parameter thresholds by the parameter threshold detection module;

sensing tissue compression by the sensing module;

monitoring multiple levels of action thresholds by the processor;

monitoring speed of the motor by the processor;

incrementing a drive unit of the motor by the processor;

sensing tissue compression by the processor; and

providing rate and control feedback by the processor to a user of the surgical instrument.

2. The method of claim 1 , comprising automatically compensating by the processor for motor load when thresholds detected by the parameter threshold detection module are within acceptable limits.

3. The method of claim 2 , comprising:

detecting battery current and speed of the motor by the parameter threshold detection module; and

increasing by the motor controller a pulse width or frequency modulation to maintain the speed of the motor constant when the battery current increases or the speed of the motor decreases.

4. The method of claim 1 , comprising detecting minimum and maximum threshold limits by the parameter threshold detection module to control operation of the surgical instrument.

5. The method of claim 4 , comprising activating the motor by the processor only after a minimum parameter threshold is detected.

6. The method of claim 4 , comprising detecting end effector closing force, end effector opening force, and speed of the motor by the parameter threshold detection module.

7. The method of claim 6 , comprising controlling the speed of the motor by the processor when the end effector closing force decreases while a knife is translating through a knife channel in the end effector.

8. The method of claim 6 , comprising activating an alarm by the processor when the end effector closing force decreases while a knife is translating through a knife channel.

9. The method of claim 1 , comprising detecting an ultimate threshold associated with current draw, end effector pressure applied to tissue, firing load, or torque, by the parameter threshold detection module, when the ultimate threshold is exceeded, the processor is configured to shut down the motor or cause the motor to retract a knife.

10. The method of claim 9 , comprising:

detecting a secondary threshold which is less than the ultimate threshold by the parameter threshold detection module; and

adapting, by the processor, control parameters to accommodate the change in operation.

11. The method of claim 9 , comprising detecting, by the parameter threshold detection module, a marginal threshold in the form of either a step function or ramp function based on a proportional response to another input to the parameter threshold detection module.

12. A method of operating a surgical instrument, the surgical instrument comprising an electric motor coupled to an end effector, a motor controller coupled to the motor, a sensing module, a processor, and a memory coupled to the processor, the memory storing executable instructions that when executed by the processor cause the processor to execute the method, the method comprising:

sensing tissue compression by the sensing module;

sensing tissue impedance by the sensing module;

measuring tissue impedance via sub-therapeutic RF energy by the sensing module coupled to electrodes;

reading overlaid multiple frequency signals by the sensing module;

measuring impedance in different locations simultaneously; and

monitoring the sensing module by the processor.

13. The method of claim 12 , wherein the sensing module is configured to sense tissue pressure.

14. The method of claim 12 , sensing tissue contact by the sensing module.

15. The method of claim 12 , comprising sensing viscoelasticity rate of change by the sensing module.

16. A method of operating a surgical instrument, the surgical instrument comprising an electric motor coupled to an end effector, a motor controller coupled to the motor, a sensing module, a processor, and a memory coupled to the processor, the memory storing executable instructions that when executed by the processor cause the processor to execute the method, the method comprising:

sensing tissue compression by the sensing module;

sensing tissue impedance by the sensing module;

measuring tissue impedance via sub-therapeutic RF energy by the sensing module coupled to electrodes;

measuring tissue impedance at variable RF frequencies sequentially by the sensing module with a multiplexor; and

monitoring the sensing module by the processor.