BACKGROUND

Surgical staplers are used to simultaneously make a longitudinal incision in tissue and apply lines of staples on opposing sides of the incision. Such instruments commonly include an end effector having a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopic applications, are capable of passing through a cannula passageway. One of the jaw members receives a staple cartridge having at least two laterally spaced rows of staples—one on each side of the knife channel. The other jaw member defines an anvil having staple-forming pockets aligned with the rows of staples in the cartridge. The instrument includes a plurality of reciprocating wedges that, when driven distally, pass through openings in the staple cartridge and engage drivers supporting the staples to effect the firing of the staples toward the anvil. Simultaneously, a cutting instrument (or knife) is drawn distally along the jaw member so that the clamped tissue is cut and fastened (e.g., stapled) at the same time.

An example of a surgical stapler suitable for endoscopic applications is described in published U.S. Patent Application Publication No. 2004/0232196, entitled, SURGICAL STAPLING INSTRUMENT HAVING SEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, now U.S. Pat. No. 7,000,818, the disclosure of which is herein incorporated by reference in its entirety. In use, a clinician is able to close the jaw members of the stapler upon tissue to position the tissue prior to firing. Once the clinician has determined that the jaw members are properly gripping tissue, the clinician can then fire the surgical stapler, thereby severing and stapling the tissue. The simultaneous severing and stapling actions avoid complications that may arise when performing such actions sequentially with different surgical tools that respectively only sever or staple.

Motor-driven endocutters are known in the art. In such devices, an electric motor powers the cutting and fastening action of the instrument. It is also known to use an on-board battery, located in the handle of the instrument, to power the motor. Published U.S. Patent Application Publication No. 2007/0175952, entitled MOTOR-DRIVEN SURGICAL CUTTING AND FASTENING INS INSTRUMENT WITH LOADING FORCE FEEDBACK, now U.S. Pat. No. 7,416,101, the disclosure of which is herein incorporated by reference in its entirety, describes one such motor-driven surgical instrument.

SUMMARY

In one general aspect, the present invention is directed to a surgical instrument with a tissue-clamping end effector, where actuation of the instrument is locked out when the thickness of the tissue clamped in the end effector is not within a specified thickness range. According to various embodiments, the end effector comprises a tissue thickness module that senses the thickness of the tissue clamped in the end effector. The surgical instrument also comprises a control circuit in communication (e.g., wireless communication) with the tissue thickness module. The control circuit prevents actuation of a working portion of the end effector when the thickness of the tissue clamped in the end effector is not within the specified thickness range. In that way, actuation of the instrument can be locked out when too much or too little tissue is clamped in the end effector. This prevents the instrument from firing in situations where it should not be fired.

According to various implementations, the end effector comprises: first and second opposing jaw members; and a disposable cartridge (such as a disposable staple cartridge) located in the first jaw member. The tissue thickness module may be part of the disposable cartridge, and may comprise a Hall effect sensor. The second jaw member may comprise a magnet, where the Hall effect sensor senses a magnetic field strength from the magnet that is indicative of the thickness of the tissue clamped in the end effector. The tissue thickness module communicates data to the control circuit, the data comprising: (i) data indicative of the thickness of the tissue clamped in the end effector; and (ii) data indicative of a cartridge type of the disposable cartridge. The control circuit may comprise a processing unit programmed to determine whether the tissue clamped in the end effector is within the specified thickness range for the disposable cartridge based on the data communicated to the control circuit by the tissue thickness module. In that connection, the control circuit may comprise solid state memory that stores thickness range data for one or more cartridge types. The processing unit may be programmed to determine whether the tissue clamped in the end effector is within the specified thickness range for the disposable cartridge based on the data communicated to the control circuit by the tissue thickness module by comparing the data indicative of the thickness of the tissue clamped in the end effector to stored thickness range data for the cartridge type of the disposable cartridge in the end effector.

