Load sensor for circular surgical stapler

A surgical instrument comprising:

• (a) a body assembly, wherein the body assembly comprises a proximal end and a distal end;
• (b) a shaft assembly, wherein the shaft assembly extends distally from the distal end of the body assembly, wherein the shaft assembly comprises a proximal end and a distal end;
• (c) a stapling head assembly, wherein the stapling head assembly is disposed at the distal end of the shaft assembly, wherein the stapling head assembly is operable to drive a plurality of staples into tissue, wherein the stapling head assembly comprises:
• (i) an anvil-driving shaft configured to selectively move between a distal position and a proximal position within the shaft assembly,
• (ii) a body member,
• (iii) a deck surface connected with the body member, and
• (iv) one or more sensors positioned between the deck surface and the body member, wherein the one or more sensors are configured to detect a parameter indicative of tissue loading between the anvil and the deck surface, wherein collectively the parameters detected are indicative of whether the tissue compressed between the anvil and the stapling head assembly is subject to a uniform or a non-uniform load;
• (d) an anvil, wherein the anvil is selectively coupleable with the anvil-driving shaft, wherein the anvil is configured to move between the distal position and the proximal position when coupled with the anvil-driving shaft;
• and
• (e) a firing member, wherein the firing member is configured to drive movement of the stapling head assembly to drive the plurality of staples into the tissue.

A method of using a circular surgical stapler having (i) a body assembly, (ii) a shaft assembly extending distally from a distal end of the body assembly, (iii) a stapling head assembly, wherein the stapling head assembly is disposed at a distal end of the shaft assembly, wherein the stapling head assembly is operable to drive a plurality of staples into tissue, wherein the stapling head assembly includes an anvil-driving shaft configured to selectively move between a distal position and a proximal position within the shaft assembly, (iv) an anvil, wherein the anvil is selectively coupleable with the anvil-driving shaft, wherein the anvil is configured to move between the distal position and the proximal position when coupled with the anvil-driving shaft, (v) a plurality of sensors connected with the anvil and defining multiple loading zones, wherein each of the sensors is configured to detect a parameter for a respective one of the multiple loading zones indicative of tissue loading between the anvil and the stapling head assembly, and (vi) a firing member, wherein the firing member is configured to drive movement of the stapling head assembly to drive the plurality of staples into the tissue, the method comprising:

• (a) locating the anvil, separate from a remainder of the surgical stapler, within a first severed end of a first portion of a tubular anatomical structure;
• (b) locating the stapling head assembly of the remainder of the surgical stapler within a second severed end of a second portion of the tubular anatomical structure;
• (c) attaching the anvil with the anvil-driving shaft;
• (d) retracting the anvil proximally toward the stapling head assembly to compress tissue between a deck surface of the stapling head assembly and the anvil;
• (e) confirming that the compressed tissue is subject to a uniform circumferential load by comparing the each of the parameters detected by each of the plurality of sensors for the respective loading zones with a predetermined threshold to ensure that none of the parameters exceed the predetermined threshold;
• (f) enabling actuation of the firing member only after the compressed tissue is subject to the uniform circumferential load according to (e);
• and
• (g) actuating the firing member to drive the plurality of staples into the tissue.