Powered stapling apparatus

1. A stapler, comprising:

a handle assembly;

a shaft extending distally from the handle assembly;

a tool assembly configured to selectively couple to the shaft and including a cartridge assembly and an anvil assembly, the cartridge assembly including a staple guide defining a tissue contacting surface and a plurality of staple retaining slots therein;

a resilient member operably positioned within the cartridge assembly and configured to bias the staple guide distally to provide a predetermined compressive force against tissue when the cartridge assembly and anvil assembly are approximated toward one another; and

a microcontroller configured to operably communicate with a motor and a power source configured to energize the motor, wherein the microcontroller is in operable communication with the cartridge assembly and configured to test a spring constant of the resilient member.

2. A stapler according to claim 1 , wherein the resilient member couples to an underside of the tissue contacting surface of the staple guide.

3. A stapler according to claim 1 , wherein the resilient member is one of a wave spring and a compression spring.

4. A stapler according to claim 1 , wherein the resilient member is shaped to complement the tissue contacting surface of the staple guide.

5. A stapler according to claim 1 , wherein at least one of the cartridge assembly and anvil assembly is circular.

6. A stapler according to claim 1 , wherein the staple guide is movable with respect the tool assembly along a longitudinal axis defined therethrough.

7. A stapler according to claim 1 , wherein the microcontroller is operably positioned within at least one of the handle assembly and shaft.

8. A stapler according to claim 7 , wherein the microcontroller is configured to compare a tested spring constant with known spring constants that are stored in memory that is accessible to the microcontroller.

9. A stapler according to claim 8 , wherein the microcontroller controls an amount of current that is supplied to the motor based on the tested spring constant of the resilient member.

10. A stapler according to claim 1 , wherein the cartridge assembly is configured to move through a test stroke for testing the spring constant of the resilient member.

11. A method for stapling tissue, the method comprising the steps of:

providing a handle assembly;

providing a tool assembly configured to operably couple to the handle assembly and including a cartridge assembly, an anvil assembly and a resilient member, the resilient member operably positioned within the cartridge assembly and configured to bias a staple guide of the cartridge assembly distally to provide a predetermined compressive force against tissue;

coupling the tool assembly to the handle assembly;

performing a test stroke for testing a spring constant of the resilient member;

adjusting an amount of current that is supplied to a motor of the handle assembly based on the tested spring constant of the spring;

approximating the cartridge assembly and anvil assembly toward one another; and

stapling tissue.

12. A method according to claim 11 , including utilizing at least one of a wave spring and a compression spring for the resilient member.

13. A method according to claim 11 , including the step of providing the handle assembly with a microcontroller that is configured to operably communicate with the motor and a power source configured to energize the motor.

14. A method according to claim 13 , including the step of comparing a tested spring constant with known spring constants that are stored in a memory and accessible by the microcontroller.

15. A method according to claim 14 , including the step of providing more current to the motor when the spring constant is above a predetermined threshold and providing less current to the motor when the spring constant is below a predetermined threshold.