Handheld Electromechanical Surgical System

Abstract

To provide a handheld electromechanical surgical system.SOLUTION: A surgical instrument includes an annular reload 400, and an anvil assembly 500 configured to move relative to the annular reload 400 between an open position and a preset closed position, where the anvil assembly 500 and the annular reload 400 define a preset gap distance therebetween. A processor of the surgical instrument is configured to determine a difference between the preset gap distance and an actual gap distance between the anvil assembly 500 and the annular reload 400, and adjust a staple stroke and a cutting stroke by the determined difference between the preset gap distance and the actual gap distance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 051,026, filed July 13, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] The present disclosure relates to surgical devices and, more particularly, to handheld electromechanical surgical systems for performing surgical procedures.

[0003] background One type of surgical device is a circular clamping, cutting, and stapling device. Such devices can be employed in surgical procedures to reattach previously severed rectal segments or similar procedures. Conventional circular clamping, cutting, and stapling instruments have a pistol-shaped or straight-gripping structure having an elongated shaft extending therefrom and a staple cartridge supported at the distal end of the elongated shaft. In this case, a physician can insert the anvil assembly of the circular stapling instrument into the patient's rectum and manipulate the anvil assembly upward along the patient's colonic canal toward the severed rectal segment. The physician can also insert the remainder of the circular stapling instrument (including the cartridge assembly) through the incision toward the severed rectal segment. The anvil assembly and cartridge assembly are approximated toward one another, staples are expelled from the cartridge assembly toward the anvil assembly to form staples in the tissue to achieve the end-to-end anastomosis, and a circular knife is fired to remove the center of a portion of the clamped tissue segments. After achieving the end-to-end anastomosis, the circular stapling device is removed from the surgical site.

[0004] Many surgical device manufacturers have developed product lines with proprietary powered drive systems for operating and / or manipulating the surgical device. Often, the surgical device includes a reusable powered handle assembly, a disposable staple cartridge assembly, and an end effector that is selectively connected to the powered handle assembly prior to use and then disconnected from the staple cartridge assembly, or that is discarded after use or, in some cases, sterilized for reuse.

[0005] The use of powered electric and endo-mechanical surgical staplers, including those with intelligent battery power sources, has grown significantly over the past several decades. The advanced technology and informatics within these intelligent, battery-powered stapling devices provide the ability to collect clinical data, drive design improvements, and ultimately improve patient outcomes. Thus, a need exists for improved powered electric and endo-mechanical surgical staplers that can assess conditions that affect staple formation with the goal of building more intelligent stapling algorithms. Summary of the Invention [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a surgical instrument is provided, including a handle assembly, an adapter assembly configured to selectively couple to the handle assembly, and an end effector. The handle assembly includes a memory having instructions stored therein and a processor configured to execute the instructions. The adapter assembly includes a trocar, and the end effector includes an anvil assembly configured to couple to the trocar and an annular reloading member configured to selectively couple to a distal portion of the adapter assembly. The anvil assembly is configured to move relative to the annular reloading member between an open position and a preset closed position, and the anvil assembly and the annular reloading member define a preset gap distance therebetween. The processor is configured to determine, using the instructions stored in the memory, a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reloading member. The processor is further configured to adjust the stapling stroke and the resecting stroke according to the determined difference between the preset gap distance and the actual gap distance.

[0007] In aspects, the annular reloading portion can include a plurality of staples, and the staple stroke can be the linear distance traveled by the staples during ejection of the staples from the annular reloading portion.

[0008] The annular reloader may further include an annular knife, and the cutting stroke may be the linear distance traveled by the annular knife during a cutting sequence of the annular knife.

[0009] In aspects, the memory may store therein a preset staple stroke and a preset resection stroke, each corresponding to a preset gap distance. The adjusted staple stroke may be the preset staple stroke minus the determined difference between the preset gap distance and the actual gap distance, and the adjusted resection stroke may be the preset resection stroke minus the difference between the preset gap distance and the actual gap distance.

[0010] In an aspect, the processor is further configured to determine whether the actual gap distance is less than the preset gap distance.

[0011] In aspects, the processor may be further configured to determine whether the force exerted on the trocar is less than a threshold force when the end effector is in the closed position. The processor may be further configured to retract the anvil assembly toward the annular reloading portion in response to determining that the force exerted on the trocar is less than the threshold force.

[0012] In aspects, the processor may be further configured to set a gap distance upon determining that the force exerted on the trocar is at a threshold force.

[0013] According to another aspect of the present disclosure, a method of using a surgical instrument is provided, comprising retracting an anvil assembly toward an annular reloading member from an open position to a closed position, wherein a gap distance defined between the anvil assembly and the annular reloading member is at a preset gap distance; further retracting the anvil assembly toward the annular reloading member from the preset gap distance to an adjusted gap distance; and adjusting a stapling stroke and a resecting stroke by a difference between the preset gap distance and the adjusted gap distance.

[0014] In aspects, the staple stroke can be the linear distance a staple travels during ejection of the staple from the annular reloader, and the cutting stroke can be the linear distance an annular knife travels during a cutting sequence of the annular knife.

[0015] In aspects, the adjusted staple stroke may be equal to the preset staple stroke minus the difference between the preset gap distance and the adjusted gap distance, and the adjusted resection stroke may be equal to the preset resection stroke minus the difference between the preset gap distance and the adjusted gap distance.

[0016] In aspects, the method may further include ejecting staples from the annular reloader with the adjusted staple stroke and advancing an annular knife from the annular reloader with the adjusted cutting stroke.

[0017] In aspects, the method may further include determining whether the force exerted by the tissue on the anvil assembly is less than a threshold force when the anvil assembly is in the closed position. The anvil assembly may be further retracted in response to determining that the force exerted on the trocar is less than the threshold force.

[0018] In aspects, the method may further include setting a gap distance upon determining that the force exerted on the anvil assembly is at the threshold force.

[0019] In another aspect of the present disclosure, a surgical instrument is provided, including an adapter assembly including a trocar, an end effector, and a handle assembly configured to couple to the adapter assembly. The end effector includes an annular reloading portion configured to selectively couple to a distal portion of the adapter assembly and an anvil assembly. The annular reloading portion includes a plurality of staples and an annular knife. The anvil assembly is coupled to the trocar and configured to move relative to the annular reloading portion between an open position and a preset closed position, the anvil assembly and the annular reloading portion defining a preset gap distance therebetween. The handle assembly includes a processor configured to determine a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reloading portion, and to adjust a staple stroke and a resection stroke according to the difference between the preset gap distance and the actual gap distance.

[0020] In aspects, the handle assembly may include a memory that stores preset staple strokes and preset resection strokes, each corresponding to a preset gap distance.

[0021] In aspects, the adjusted staple stroke can be the preset staple stroke minus the determined difference between the preset gap distance and the actual gap distance. The adjusted resection stroke can be the preset resection stroke minus the determined difference between the preset gap distance and the actual gap distance. For example, the present application provides the following: (Item 1) 1. A surgical instrument comprising: a handle assembly including a memory having instructions stored therein and a processor configured to execute said instructions; an adapter assembly configured to selectively couple to the handle assembly, the adapter assembly including a trocar; An end effector, an annular reloading portion configured to selectively couple to a distal portion of the adapter assembly; and an end effector including an anvil assembly configured to be coupled to the trocar and to move relative to the annular reload member between an open position and a preset closed position, the anvil assembly and the annular reload member defining a preset gap distance therebetween; The processor uses the instructions stored in the memory to: determining a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reload member; adjusting a stapling stroke and a resecting stroke according to the determined difference between the preset gap distance and the actual gap distance. (Item 2) 10. The surgical instrument of claim 9, wherein the annular reloading member includes a plurality of staples, and the staple stroke is the linear distance traveled by the staples during ejection of the staples from the annular reloading member. (Item 3) 10. The surgical instrument of claim 9, wherein the annular reloader further includes an annular knife, and the cutting stroke is a linear distance traveled by the annular knife during a cutting sequence of the annular knife. (Item 4) 10. The surgical instrument of claim 9, wherein the memory stores therein a preset staple stroke and a preset cutting stroke, each corresponding to the preset gap distance, and wherein the adjusted staple stroke is the preset staple stroke minus the determined difference between the preset gap distance and the actual gap distance, and the adjusted cutting stroke is the preset cutting stroke minus the difference between the preset gap distance and the actual gap distance. (Item 5) 10. The surgical instrument of claim 1, wherein the processor is further configured to determine whether the actual gap distance is less than the preset gap distance. (Item 6) The processor: determining whether a force exerted on the trocar is less than a threshold force when the end effector is in a closed position; responsive to determining that the force exerted on the trocar is less than the threshold force, retracting the anvil assembly toward the annular reloading member. (Item 7) 10. The surgical instrument of claim 1, wherein the processor is further configured to set the gap distance when the processor determines that the force exerted on the trocar is at the threshold force. (Item 8) 1. A method of using a surgical instrument, comprising: retracting an anvil assembly toward an annular reload section from an open position to a closed position, wherein a gap distance defined between the anvil assembly and the annular reload section is a preset gap distance; further retracting the anvil assembly toward the annular reload section from the preset gap distance to an adjusted gap distance; and adjusting a stapling stroke and a cutting stroke according to a difference between the preset gap distance and the adjusted gap distance. (Item 9) 10. The method of claim 9, wherein the staple stroke is the linear distance traveled by the staple during ejection of the staple from the annular reloading station and the cutting stroke is the linear distance traveled by the annular knife during a cutting sequence of the annular knife. (Item 10) 10. The method of claim 9, wherein the adjusted staple stroke is equal to the preset staple stroke minus the difference between the preset gap distance and the adjusted gap distance, and the adjusted resection stroke is equal to the preset resection stroke minus the difference between the preset gap distance and the adjusted gap distance. (Item 11) ejecting the staples from the annular reloading station with the adjusted staple stroke; 10. The method of claim 9, further comprising: advancing the annular knife from the annular reloading station through the adjusted cutting stroke. (Item 12) The method of any one of the preceding items, further comprising determining whether a force exerted by tissue on the anvil assembly when the anvil assembly is in the closed position is less than a threshold force, wherein the anvil assembly is further retracted in response to determining that the force exerted on the anvil assembly is less than the threshold force. (Item 13) 10. The method of claim 1, further comprising setting the gap distance upon determining that the force exerted on the anvil assembly is at the threshold force. (Item 14) 1. A surgical instrument comprising: an adapter assembly including a trocar; An end effector, an annular reloading portion configured to selectively couple to a distal portion of the adapter assembly, the annular reloading portion including a plurality of staples and an annular knife; and an end effector including an anvil assembly configured to be coupled to the trocar and to move relative to the annular reload member between an open position and a preset closed position, the anvil assembly and the annular reload member defining a preset gap distance therebetween; a handle assembly configured to couple to the adapter assembly, determining a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reload member; and adjusting a stapling stroke and a resecting stroke according to the determined difference between the preset gap distance and the actual gap distance. (Item 15) The surgical instrument of the preceding item, wherein the staple stroke is the linear distance traveled by the staple during ejection of the staple from the annular reloading portion, and the cutting stroke is the linear distance traveled by the annular knife during a cutting sequence of the annular knife. (Item 16) 10. The surgical instrument of claim 1, wherein the handle assembly further includes a memory that stores a preset stapling stroke and a preset resecting stroke, each corresponding to the preset gap distance. (Item 17) 10. The surgical instrument of claim 9, wherein the adjusted staple stroke is the preset staple stroke minus the determined difference between the preset gap distance and the actual gap distance, and the adjusted resection stroke is the preset resection stroke minus the difference between the preset gap distance and the actual gap distance. (Item 18) 10. The surgical instrument of claim 1, wherein the processor is further configured to determine whether the actual gap distance is less than the preset gap distance. (Item 19) The processor: determining whether a force exerted on the trocar is less than a threshold force when the end effector is in the preset closed position; responsive to determining that the force exerted on the trocar is less than the threshold force, retracting the anvil assembly toward the annular reloading member. (Item 20) 10. The surgical instrument of claim 1, wherein the processor is further configured to set the gap distance when the processor determines that the force exerted on the trocar is at the threshold force. (Summary) The surgical instrument includes an annular reloading member and an anvil assembly configured to move relative to the annular reloading member between an open position and a preset closed position, the anvil assembly and the annular reloading member defining a preset gap distance therebetween, and a processor of the surgical instrument configured to determine a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reloading member, and to adjust the stapling stroke and the resecting stroke according to the determined difference between the preset gap distance and the actual gap distance. [Brief explanation of the drawings]

[0022] Embodiments of the present disclosure are described herein with reference to the accompanying drawings. [Figure 1] FIG. 1 is a perspective view of a handheld surgical instrument including a handle assembly, an adapter assembly, and an end effector according to one embodiment of the present disclosure; [Figure 2] Figure 1 shows a schematic diagram of the handle assembly, adapter assembly, and end effector. [Figure 3] FIG. 1 is a side perspective view of an adapter assembly and an end effector (e.g., an annular reloading portion and an anvil assembly) attached to the adapter assembly. [Figure 4] FIG. 1 is a perspective view of an adapter assembly, partially in see-through, without an end effector (e.g., an annular reloading portion and anvil assembly). [Figure 5A] 2 is a flowchart of a method for performing the stapling function of the surgical instrument of FIG. 1 . [Figure 5B] 2 is a flowchart of a method for performing the cutting function of the surgical instrument of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0023] Embodiments of the presently disclosed surgical device, adapter assembly for a surgical device, and / or handle assembly will now be described in detail with reference to the drawings, in which like reference numerals indicate identical or corresponding elements in each of the several views. As used herein, the term "distal" refers to that portion of, or component of, a surgical instrument that is farther from the user, while the term "proximal" refers to that portion of, or component of, a surgical instrument that is closer to the user.

[0024] An intelligent surgical instrument, such as a handheld surgical instrument, includes a handle assembly, an adapter assembly coupled to the handle assembly, and an end effector coupled to the adapter assembly. The stapler allows for fully independent control of three functions: clamping, stapling, and resection. This allows certain parts of the stapler to adapt when tissue presents less-than-ideal conditions. For example, when very thin tissue is being treated, it may be advantageous to move the anvil of the end effector closer to the distal end of the adapter assembly to ensure the anvil is attached to the adapter assembly.

[0025] The present disclosure relates to software that allows for and compensates for anvil movement in situations where the stapler is already fully clamped and the anvil is below the target threshold load. In this case, the stapler may move the anvil toward (e.g., proximally) the adapter assembly until the target threshold load is detected. To account for this, the staple stroke and resection stroke are adjusted to a corresponding delta anvil position. This maintains consistent firing regardless of clamp distance. The adjusted staple stroke maintains consistent staple crimping even with misaligned anvils, and the adjusted resection stroke ensures the correct resection distance regardless of anvil position.

[0026] FIG. 1 illustrates a surgical instrument, such as, for example, a circular stapler 1, including a handle assembly 100 configured to selectively connect with an adapter assembly 200, which in turn is configured to selectively connect with an end effector 300 including a reloading portion 400 (of multiple reloading portions) and an anvil assembly 500. The end effector 300 is configured to deliver a surgical effect to patient tissue. The handle assembly 100 is a powered, electromechanical handle assembly including a power handle 101 (FIG. 2) and a shell housing 10 configured to selectively receive and house the power handle 101. The shell housing 10 includes a distal half 10a and a proximal half 10b pivotally connected to the distal half 10a. When joined together, the distal and proximal halves 10a, 10b define a shell cavity within which the power handle 101 is selectively positioned.

[0027] Distal and proximal halves 10a, 10b of shell housing 10 are divided along a plane transverse to longitudinal axis "X" of adapter assembly 200. Distal half 10a of shell housing 10 defines connecting portion 20 configured to receive a corresponding drive coupling assembly 210 ( FIG. 3 ) of adapter assembly 200. Distal half 10a of shell housing 10 supports distally facing toggle control button 30. Toggle control button 30 can be actuated in left, right, up, and down directions upon application of a corresponding force or depressing force thereto.

[0028] 1 and 2, the power handle 101 includes a controller circuit board 142, a rechargeable battery 144 configured to power any of the electrical components of the handle assembly 100, and a motor 152 coupled to the battery 144. In embodiments, the motor 152 may be coupled to any suitable power source configured to provide electrical energy to the motor 152, such as an AC / DC transformer. The battery 144 and motor 152 are coupled to the motor controller circuit board 142, which has a motor controller 143 that controls the operation of the motor 152, including the flow of electrical energy from the battery 144 to the motor 152. A main controller 147 is provided that controls the power handle 101.

[0029] The motor controller 143 includes multiple sensors 408a, 408b, ... 408n configured to measure the operating conditions of the motor 152 and the battery 144. The sensors 408a-n may include voltage sensors, current sensors, temperature sensors, telemetry sensors, optical sensors, and combinations thereof. The sensors 408a-408n may measure the voltage, current, and other electrical characteristics of the electrical energy supplied by the battery 144. The sensors 408a-408n may also measure the angular velocity (e.g., rotational speed) of the motor 152 as revolutions per minute (RPM), torque, temperature, current draw, and other operating characteristics. The angular velocity may be determined by measuring the rotation of the motor 152 or a drive shaft (not shown) coupled to and rotatable by the motor 152. The position of the drive shaft, which may be movable in various axial directions, may also be determined using various linear sensors disposed in or near the shaft or may be estimated from RPM measurements. In embodiments, torque may be calculated based on the adjusted current draw of motor 152 at a constant RPM. In further embodiments, motor controller 143 and / or main controller 147 may measure time and process the values ​​as a function of time, including integration and / or differentiation, to determine, for example, the rate of change of the measurements. Main controller 147 is also configured to determine the distance traveled by various components of circular adapter assembly 200 and / or end effector 300 by counting the number of rotations of motor 152.

[0030] Motor controller 143 is coupled to main controller 147, which includes multiple inputs and outputs for interfacing with motor controller 143. Specifically, main controller 147 receives measured sensor signals from motor controller 143 regarding the operating conditions of motor 152 and battery 144, and then outputs control signals to motor controller 143 for controlling the operation of motor 152 based on the sensor readings and specific algorithm instructions. Main controller 147 is also configured to accept multiple user inputs from a user interface (e.g., switches, buttons, touchscreen, etc. coupled to main controller 147).

[0031] The main controller 147 is also coupled to the memory 141. The memory 141 may include volatile (e.g., RAM) and non-volatile storage configured to store data including software instructions for operating the power handle 101. The main controller 147 is also coupled to the strain gauges (not explicitly shown) of the circular adapter assembly 200 using a wired or wireless connection and is configured to receive strain measurements from the strain gauges used during operation of the power handle 101.

[0032] In addition to the first motor 152, the power handle 101 further includes a second motor (not explicitly shown) and a third motor (not explicitly shown), each electrically connected to the controller circuit board 142 and the battery 144. Each motor 152 includes a respective motor shaft (not explicitly shown) extending therefrom. Rotation of the motor shaft by each motor 152 functions to drive shafts and / or gear components of the adapter assembly 200 to perform various operations of the handle assembly 100. Specifically, the motor 152 of the power handle 101 is configured to drive the shaft and / or gear components of the adapter assembly 200 to selectively extend / retract the trocar member 274 (FIG. 4) of the trocar assembly 270 of the adapter assembly 200, open and close the end effector 300 (when the anvil assembly 500 is connected to the trocar member 274 of the trocar assembly 270), fire the annular array of staples of the reloading portion 400, and fire the annular knife (not explicitly shown) of the reloading portion 400.

[0033] 3-4 , adapter assembly 200 includes an outer knob housing 202 and an outer tube 206 extending from a distal end of knob housing 202. Knob housing 202 and outer tube 206 are configured and dimensioned to accommodate the components of adapter assembly 200. Adapter assembly 200 is configured to convert rotation of a coupling shaft (not expressly shown) of handle assembly 100 into axial translation useful for operation of trocar assembly 270, anvil assembly 500, and / or staple driver assembly (not expressly shown) of adapter assembly 200, or a knife assembly (not expressly shown) of reloader 400.

[0034] Adapter assembly 200 further includes a trocar assembly 270 removably supported on the distal end of outer tube 206. Trocar assembly 270 includes a trocar member 274 and a drive screw 276 operably received within trocar member 274 for axially moving trocar member 274 relative to outer tube 206. Distal end 274b of trocar member 274 is configured to selectively engage anvil assembly 500 such that axial movement of trocar member 274 results in concomitant axial movement of anvil assembly 500 via rotation of drive screw 276.

[0035] The force during actuation of the trocar member 274 or closure of the end effector 300 (e.g., retraction of the anvil assembly 500 relative to the reloading portion 400) can be measured by strain gauges to monitor and control the firing of the staples from the reloading portion 400, monitor the force during the firing and formation of the staples as they are ejected from the reloading portion 400, optimize the formation of the staples (e.g., staple crimp height) as they are ejected from the reloading portion 400 for different tissue indications, and monitor and control the firing of the annular knife of the reloading portion 400.

[0036] The strain gauges of the adapter assembly 200 measure and monitor the retraction of the trocar member 274. If the anvil assembly 500 contacts a tissue contacting surface, such as tissue, an obstruction, or the annular reloading member 400, during closure of the end effector 300, a reaction force generally in the distal direction is exerted on the anvil assembly 500. This distally directed reaction force is transmitted from the anvil assembly 500 to the strain gauges. The strain gauges then transmit a signal to the main controller circuit board 142 of the power handle 101 of the handle assembly 100. Graphics are then displayed on a display screen (not shown) of the handle assembly 100, providing the user with real-time information related to the firing status of the handle assembly 100.

[0037] For further details regarding the structure and operation of the circular stapler and its components, reference may be made to International Patent Application No. PCT / US2019 / 040440, filed July 3, 2019, the entire contents of which are incorporated herein by reference.

[0038] In operation, the anvil assembly 500 (already positioned by the surgeon) is attached to the trocar member 274, and the user initiates the clamping process of tissue placed between the circular reload portion 400 and the anvil assembly 500 by pressing the bottom of the toggle control button 30. During clamping, the anvil assembly 500 moves back toward the circular reload portion 400 until it reaches a preset fully clamped position, i.e., the position of the anvil assembly 500 where the tissue is fully clamped between the anvil assembly 500 and the reload portion 400. The preset fully clamped position varies for each different type of reload portion (e.g., the distance is approximately 29 mm for a 25 mm reload portion). During clamping, the strain gauge continuously provides measurements to the main controller 147 of the force applied to the trocar member 274 as the anvil assembly 500 is moved to compress the tissue between the anvil assembly 500 and the anvil assembly 500.

[0039] Once the fully clamped position (e.g., a preset gap distance defined between the anvil assembly 500 and the annular reloading portion 400) is reached, the main controller 147 uses measurements made by the strain gauges to determine whether the measured force is at or below a target threshold load. If the main controller 147 determines that the measured force is less than the target threshold load, this indicates that the clamped tissue is too thin, and therefore the gap distance between the anvil assembly 500 and the reloading portion 400 needs to be reduced below the preset gap distance of the fully clamped position. Thus, the anvil assembly 500 is retracted further beyond the fully clamped position until the target threshold load is detected, thereby indicating that the anvil assembly 500 is in an over-clamped condition. Because the gap distance between the anvil assembly 500 and the reloader 400 is smaller than the pre-programmed gap distance of the end effector 300, the total amount of distal movement of the staple and annular knife during the stapling and resection sequences, respectively (e.g., the staple stroke and the resection stroke, respectively) should also be adjusted.

[0040] 5A, which shows a flowchart of the stapling process, software stored in memory 141 instructs main controller 147 to determine whether anvil assembly 500 is in the over-clamped state described above. If main controller 147 determines that anvil assembly 500 has retracted into the over-clamped state (e.g., because of tissue thinner than a pre-programmed gap distance), main controller 147 calculates a staple adjustment. The staple adjustment may include decreasing the staple stroke distance compared to a preset staple stroke. The preset staple stroke may be adjusted (e.g., decreased) by the difference between the gap distance in the over-clamped state and the gap distance in the fully clamped state.

[0041] To initiate the stapling sequence, the user depresses the toggle control button 30, which ejects staples from the reloader 400 into the anvil assembly 500 and deforms the staples through the tissue. The staples are ejected from the reloader 400 with a coordinated staple stroke to staple the tissue. The main controller 147 determines that the stapling process is successfully completed when the measured strain is within the minimum and maximum staple force limits. Staple firing progress is indicated by an animation of the anastomosis, a firing progress bar, and staple formation.

[0042] 5B, which shows a flowchart of the resection process, software stored in memory 141 includes instructions that, when executed by main controller 147, enable main controller 147 to determine whether anvil assembly 500 is in an over-clamped state. If main controller 147 determines that anvil assembly 510 is approaching an over-clamped state (e.g., because it has tissue thinner than a pre-programmed gap distance), main controller 147 calculates a resection adjustment, such as a reduction in the resection stroke compared to a preset resection stroke. The preset resection stroke is adjusted (e.g., reduced) by the difference between the gap distance in the over-clamped state and the gap distance in the fully clamped state. Thus, when the resection function is activated, the knife moves from reloader 400 by the adjusted resection stroke.

[0043] It should be understood that various modifications may be made to the embodiments of the presently disclosed adapter assembly. Accordingly, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure.

[0044] In one or more embodiments, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may include a non-transitory computer-readable medium corresponding to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0045] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term "processor," as used herein, may refer to any of the above structures, or any other physical structure suitable for implementing the described techniques. Also, the techniques may be implemented entirely in one or more circuits or logic elements.

Claims

1. 1. A surgical instrument comprising: a handle assembly including a memory having instructions stored therein and a processor configured to execute said instructions; an adapter assembly configured to selectively couple to the handle assembly, the adapter assembly including a trocar; An end effector, an annular reloading portion configured to selectively couple to a distal portion of the adapter assembly; and an end effector including an anvil assembly configured to be coupled to the trocar and to move relative to the annular reload member between an open position and a preset closed position, the anvil assembly and the annular reload member defining a preset gap distance therebetween; The processor uses the instructions stored in the memory to: determining a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reload member; adjusting a stapling stroke and a resecting stroke according to the determined difference between the preset gap distance and the actual gap distance.

2. The surgical instrument of claim 1 , wherein the annular reloading member includes a plurality of staples, and the staple stroke is the linear distance traveled by the staples during ejection of the staples from the annular reloading member.

3. The surgical instrument of claim 2 , wherein the annular reloader further includes an annular knife, and the cutting stroke is a linear distance traveled by the annular knife during a cutting sequence of the annular knife.

4. 4. The surgical instrument of claim 3, wherein the memory stores therein a preset staple stroke and a preset resection stroke, each corresponding to the preset gap distance, and wherein the adjusted staple stroke is the preset staple stroke minus the determined difference between the preset gap distance and the actual gap distance, and the adjusted resection stroke is the preset resection stroke minus the difference between the preset gap distance and the actual gap distance.

5. The surgical instrument of claim 1 , wherein the processor is further configured to determine whether the actual gap distance is less than the preset gap distance.

6. the processor: determining whether a force exerted on the trocar is less than a threshold force when the end effector is in a closed position; The surgical instrument of claim 1, further configured: in response to determining that the force exerted on the trocar is less than the threshold force, retracting the anvil assembly toward the annular reloading member.

7. The surgical instrument of claim 6, wherein the processor is further configured to set the gap distance when the force exerted on the trocar is determined to be at the threshold force.

8. 1. A method of operating a surgical instrument, the surgical instrument comprising a processor, an anvil assembly, and an annular reloader, the method comprising: the processor retracting the anvil assembly toward the annular reloading portion from an open position to a closed position, wherein in the closed position a gap distance defined between the anvil assembly and the annular reloading portion is a preset gap distance; the processor further retracting the anvil assembly toward the annular reload section from the preset gap distance to an adjusted gap distance; the processor adjusting a stapling stroke and a resecting stroke according to a difference between the preset gap distance and the adjusted gap distance.

9. 9. The method of claim 8, wherein the staple stroke is the linear distance traveled by the staple during ejection of the staple from the annular reloader, and the cutting stroke is the linear distance traveled by the annular knife during a cutting sequence of the annular knife.

10. 10. The method of claim 9, wherein the adjusted staple stroke is equal to a preset staple stroke minus the difference between the preset gap distance and the adjusted gap distance, and wherein the adjusted resection stroke is equal to a preset resection stroke minus the difference between the preset gap distance and the adjusted gap distance.

11. 11. The method of claim 10, further comprising the processor advancing the annular knife from the annular reloading member with the adjusted cutting stroke, and wherein the staples are ejected from the annular reloading member with the adjusted staple stroke.

12. 9. The method of claim 8, further comprising: when the anvil assembly is in the closed position, the processor determining whether a force exerted by tissue on the anvil assembly is less than a threshold force; and wherein the anvil assembly is further retracted by the processor in response to the processor determining that the force exerted on the anvil assembly is less than the threshold force.

13. The method of claim 12, further comprising the processor setting the gap distance when the processor determines that the force exerted on the anvil assembly is at the threshold force.

14. 1. A surgical instrument comprising: an adapter assembly including a trocar; An end effector, an annular reloading portion configured to selectively couple to a distal portion of the adapter assembly, the annular reloading portion including a plurality of staples and an annular knife; and an end effector including an anvil assembly configured to be coupled to the trocar and to move relative to the annular reload member between an open position and a preset closed position, the anvil assembly and the annular reload member defining a preset gap distance therebetween; a handle assembly configured to couple to the adapter assembly, determining a difference between the preset gap distance and an actual gap distance between the anvil assembly and the annular reload member; and adjusting a stapling stroke and a resecting stroke according to the determined difference between the preset gap distance and the actual gap distance.

15. 15. The surgical instrument of claim 14, wherein the staple stroke is the linear distance traveled by the staple during ejection of the staple from the annular reloader, and the cutting stroke is the linear distance traveled by the annular knife during a cutting sequence of the annular knife.

16. The surgical instrument of claim 15, wherein the handle assembly further includes a memory that stores a preset stapling stroke and a preset resecting stroke, each corresponding to the preset gap distance.

17. 17. The surgical instrument of claim 16, wherein the adjusted staple stroke is the preset staple stroke minus the determined difference between the preset gap distance and the actual gap distance, and the adjusted resection stroke is the preset resection stroke minus the difference between the preset gap distance and the actual gap distance.

18. The surgical instrument of claim 14, wherein the processor is further configured to determine whether the actual gap distance is less than the preset gap distance.

19. the processor: determining whether a force exerted on the trocar is less than a threshold force when the end effector is in the preset closed position; The surgical instrument of claim 14, further configured: in response to determining that the force exerted on the trocar is less than the threshold force, retracting the anvil assembly toward the annular reloading member.

20. The surgical instrument of claim 19, wherein the processor is further configured to set the gap distance when the processor determines that the force exerted on the trocar is at the threshold force.

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