Slow Staple and Staple Relaxation for Optimized Stapling

Abstract

The powered surgical device includes a power source and a motor coupled to the power source. The device may include a reload having a plurality of staples. The device may also include a transmission assembly movable by the motor. The device may also include a sensor configured to monitor operation of the transmission assembly and output sensor data. The device may also include a controller configured to determine a position of the transmission assembly and operate the motor based on the position of the transmission assembly to advance the transmission assembly and eject the plurality of staples from the reload. The controller is further configured to stop the motor when the plurality of staples have been ejected from the reload for a preset period of time.

Description

[Technical field]

[0001] The present disclosure relates to surgical devices and, more particularly, to a handheld powered surgical stapler having a stapling optimization algorithm. [Background technology]

[0002] Circular staplers are used in surgical procedures to reattach previously severed rectal segments, or similar procedures. Conventional circular clamping, cutting and stapling instruments include a pistol or straight grip design with an elongated shaft extending from the instrument and a staple cartridge supported at the distal end of the elongated shaft. In this case, the physician may insert the anvil assembly of the circular stapling instrument through the incision toward the transected rectal segment. The physician may then introduce the remaining portion of the circular stapling instrument (including the cartridge assembly) into the patient's rectum and manipulate the device up the patient's colonic tract toward the transected rectal segment. The anvil and cartridge assemblies are approximated toward each other, staples are expelled from the cartridge assembly toward the anvil assembly to form the staples in the tissue to effect an end-to-end anastomosis, and an annular knife is advanced to carve out a portion of the clamped tissue segment. After the end-to-end anastomosis has been effected, the circular stapling apparatus is removed from the surgical site.

[0003] Powered surgical staplers utilize one or more motors to clamp, cut, and staple tissue. During the stapling process, the actuators move rapidly through various tissue types and thicknesses, which can result in deformed staples. Thus, there is a need for a powered surgical stapler configured to control staple deployment and formation to reduce the risks associated with deformed staples. Summary of the Invention [Means for solving the problem]

[0004] According to one embodiment of the present disclosure, a powered surgical device is disclosed. The surgical device may include a power source and a motor coupled to the power source. The device may include a reload having a plurality of staples. The device may include a transmission assembly movable by the motor. The device may include a sensor configured to monitor operation of the transmission assembly and output sensor data. The device may also include a controller configured to determine a position of the transmission assembly and operate the motor based on the position of the transmission assembly to advance the transmission assembly and eject the plurality of staples from the reload. The controller is further configured to stop the motor when the plurality of staples have been ejected from the reload for a preset period of time.

[0005] Implementations of the above embodiment may include one or more of the following features. According to one aspect of the above embodiment, the transmission assembly may further include a stapler driver. The sensor may include a strain gauge configured to measure a force applied to the transmission assembly. The controller is further configured to operate the motor to advance the staple driver from the first position to the second position at a first speed. The controller is further configured to operate the motor to advance the staple driver from the second position to the third position at a second speed slower than the first speed. The controller is further configured to determine that the measured force is within a range having a minimum force threshold and a maximum force threshold. The preset time is between about 1 second and about 10 seconds. The controller is further configured to determine the force measured during the preset time period. The controller is further configured to determine whether the plurality of staples are properly formed during the preset time period. The controller is further configured to operate the motor to retract the transmission assembly. The controller is configured to determine that a plurality of staples are to be discharged from the reload based on at least one of the positions of the position of the transfer assembly.

[0006] According to another embodiment of the present disclosure, a method for controlling a powered surgical stapler is disclosed. The method includes actuating a motor coupled to a transmission assembly. The method may also include advancing a transmission assembly having a stapler driver configured to engage a reload. The method may also include determining a position of the transmission assembly. The method may further include ejecting a plurality of staples from the reload by the stapler driver. The method may also include stopping the motor after the plurality of staples have been ejected from the reload for a preset period of time.

[0007] Implementations of the above embodiment may include one or more of the following features. According to one aspect of the above embodiment, the method may include measuring a force applied to the transmission assembly at a strain gauge. The method may also include advancing the staple driver from a first position to a second position at a first speed. The method may further include advancing the staple driver from the second position to a third position at a second speed slower than the first speed. The method may also include determining that the measured force is within a range having a minimum force threshold and a maximum force threshold. The motor may be stopped for about 1 second to about 10 seconds. The method may also include measuring a force applied to the transmission assembly during a preset period of time. The method may further include determining whether the plurality of staples are properly formed based on the force measured during the preset period of time. The method may further include retracting the transmission assembly after releasing the plurality of staples from the reload.

[0008] Embodiments of the present disclosure are described herein with reference to the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a powered circular stapler including a handle assembly, an adapter assembly, and an end effector according to an embodiment of the present disclosure.

[0010] [Diagram 2] FIG. 2 is a schematic diagram of the handle assembly, adapter assembly, and end effector of FIG. 1.

[0011] [Diagram 3] FIG. 2 is a side perspective view of an adapter assembly and an end effector, annular reload, and an anvil assembly attached to the adapter assembly of FIG. 1 in accordance with an embodiment of the present disclosure.

[0012] [Figure 4] 2 is a perspective view of a clamp transfer assembly disposed within the adapter assembly of FIG. 1, shown partially in phantom.

[0013] [Diagram 5] 2 is a perspective view of a stapling transfer assembly disposed within the adapter assembly of FIG. 1 , partially shown in phantom;

[0014] [Figure 6] FIG. 2 is a cross-sectional view of a reload of the end effector of FIG. 1;

[0015] [Figure 7] FIG. 2 is a perspective view of an adapter assembly having a strain gauge assembly shown partially disassembled.

[0016] [Figure 8] 2 is a schematic diagram illustrating the travel distance and speed of a driver and corresponding motor during a stapling sequence performed by the handheld surgical device of FIG. 1 according to one embodiment of the present disclosure.

[0017] [Figure 9] 11 is a flowchart of a method for controlling the powered circular stapler during the stapling process of FIG. 10 according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Embodiments of the presently disclosed surgical device, and adapter and / or handle assemblies for the surgical device, are 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 a portion of the surgical instrument or a component thereof that is further from the user, while the term "proximal" refers to a portion of the surgical instrument or a component thereof that is closer to the user.

[0019] The present disclosure provides a powered circular stapler 10 having a handle assembly, an adapter assembly coupled to the handle assembly, and an end effector coupled to the adapter assembly. The stapler allows for complete independent control of the three functions of clamping, stapling, and cutting. This allows certain portions of the stapler to adapt even when tissue presents non-ideal conditions.

[0020] 1 illustrates a surgical device, such as, for example, a powered circular stapler 10 for forming an end-to-end anastomosis ("EEA"), including a handle assembly 100 configured for selective connection with an adapter assembly 200. The adapter assembly 200 is configured for selective connection with an end effector 300 including a reload 400 and an anvil assembly 500. The end effector 300 is configured to produce a surgical effect on tissue of a patient, i.e., to form an anastomosis by connecting two portions of a structure (e.g., an intestine, colon, etc.) by clamping, stapling, and cutting tissue grasped within the end effector 300.

[0021] The handle assembly 100 includes a power handle 101 and an outer shell housing 11 configured to selectively receive and encase the power handle 101. The shell housing 11 includes a distal half 11a and a proximal half 11b pivotally connected to the distal half 11a. When coupled, the distal and proximal halves 11a and 11b define a shell cavity therein in which the power handle 101 is disposed.

[0022] Although the powered circular stapler 10 is described herein as a modular device including multiple interconnected components, such as a handle assembly 100, a removable shell housing 11, and an adapter assembly 200, the powered circular stapler 10 may be formed as an integrated device in which one or more of the components are securely attached to one another, for example, during manufacture of the powered circular stapler.

[0023] Distal half 11a and proximal half 11b of shell housing 11 are divided along a plane transverse to a longitudinal axis "X" of adapter assembly 200. Distal half 11a of shell housing 11 defines a connecting portion 20 configured to receive a corresponding drive coupling assembly 210 (FIG. 3) of adapter assembly 200. Distal half 11a of shell housing 11 supports a toggle control button 30. Toggle control button 30 can be actuated in four directions (e.g., left, right, up, and down).

[0024] 1 and 2, the power handle 101 includes a main controller circuit board 142, a rechargeable battery 144 configured to power any of the electrical components of the handle assembly 100, and a number of motors, a first motor 152a, a second motor 152b, coupled to the battery 144. The power handle 101 also includes a display 146. In an embodiment, the motors 152a and 152b may be coupled to any suitable power source configured to provide electrical energy to the motors 152a and 152b, such as an AC / DC transformer. Each of the motors 152a and 152b is coupled to a motor controller 143 that controls the operation of the corresponding motors 152a and 152b, including the flow of electrical energy from the battery 144 to the motors 152a and 152b. A main controller 147 is provided to control the power handle 101. The main controller 147 is configured to execute software instructions embodying the algorithms disclosed herein, such as the clamping, stapling, and cutting algorithms that control the operation of the power handle 101.

[0025] The motor controller 143 includes a number of sensors 408a...408n configured to measure the operating conditions of the motors 152a and 152b and the battery 144. The sensors 408a-n include a strain gauge 408b and may also 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 provided by the battery 144. The sensors 408a-408n may also measure the angular velocity (e.g., rotational speed) in revolutions per minute (RPM), torque, temperature, current draw, and other operating characteristics of the motors 152a and 152b. The sensor 408a also includes an encoder configured to count revolutions or other metrics of the motors 152a and 152b, which is then used by the main controller 147 to calculate the linear movement of components moveable by the motors 152a and 152b. The angular velocity may be determined by measuring the rotation of the motors 152a and 152b, or a drive shaft (not shown) coupled thereto and rotatable by the motors 152a and 152b. The position of the drive shaft movable in various axial directions may also be determined by using various linear sensors disposed in or proximate the shaft, or may be extrapolated from the RPM measurements. In an embodiment, the torque may be calculated based on the adjusted current draw of the motors 152a and 152b at a constant RPM. In a further embodiment, the motor controller 143 and / or the main controller 147 may measure time and process the above values ​​as a function of time, including integrals and / or derivatives, to determine, for example, the rate of change in the measurements. The main controller 147 is also configured to determine the distance traveled by various components of the adapter assembly 200 and / or the end effector 300 by counting the rotations of the motors 152a and 152b.

[0026] The motor controller 143 couples to a main controller 147 that includes multiple inputs and outputs for interfacing with the motor controller 143. In particular, the main controller 147 receives measured sensor signals from the motor controller 143 regarding the operating conditions of the motors 152a and 152b and the battery 144, and then outputs control signals to the motor controller 143 to control the operation of the motors 152a and 152b based on the sensor readings and specific algorithm instructions. The main controller 147 is also configured to accept multiple user inputs from a user interface (e.g., switches, buttons, touch screen, etc. coupled to the main controller 147).

[0027] The main controller 147 also couples to the memory 141. The memory 141 may include volatile (e.g., RAM) and non-volatile storage devices configured to store data including software instructions for operating the power handle 101. The main controller 147 is also configured to couple to the strain gauges 408b of the adapter assembly 200 using a wired or wireless connection and to receive strain measurements from the strain gauges 408b that are used during operation of the power handle 101.

[0028] The power handle 101 includes a plurality of motors 152a and 152b, each including a respective motor shaft (not explicitly shown) extending therefrom and configured to drive a respective transmission assembly. Rotation of the motor shaft by the respective motor functions to drive a shaft and / or gear components of the adapter assembly 200 to effect various operations of the handle assembly 100. In particular, the motors 152a and 152b of the power handle 101 are configured to drive the shaft and / or gear components of the adapter assembly 200 to selectively extend / retract a trocar member 274 ( FIG. 4 ) of a trocar assembly 270 of the adapter assembly 200. Extension / retraction of the trocar member 274 opens and closes the end effector 300 (when the anvil assembly 500 is connected to the trocar member 274 of the trocar assembly 270), fires the annular array of staples 423 of the reload 400, and moves the annular knife 444 of the reload 400.

[0029] The reload 400 includes a storage device 402 configured to store operating parameters of the reload 400, including a starting clamping force, a maximum clamping force, a force factor, etc. Each type of reload 400 may have a corresponding starting clamping force, which may be obtained automatically by the main controller 147 by reading from the storage device 402, and / or may be set manually by a user by directly selecting either the type of reload 400 or the clamping force. The starting clamping force may be any suitable threshold value between about 100 pounds and about 200 pounds, and in an embodiment, the target clamping force may be about 150 pounds. In an embodiment, a 33 mm size reload 400 may have a clamping force of about 150 lbs.

[0030] 3 and 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. Knob housing 202 includes an electrical connector 312 and a storage device 310 coupled thereto. Storage device 310 is configured to store various operating parameters for adapter assembly 200. Adapter assembly 200 is configured to convert rotation of a mating shaft (not explicitly shown) of handle assembly 100 into axial translation useful for operating trocar assembly 270, anvil assembly 500, and / or staple driver 430 or knife assembly 440 of reload 400 of adapter assembly 200.

[0031] The adapter assembly 200 further includes a trocar assembly 270 removably supported on a distal end of the outer tube 206. The trocar assembly 270 includes a trocar member 274 and a drive screw 276 operably received within the trocar member 274 for axially moving the trocar member 274 relative to the outer tube 206. The distal end 274b of the trocar member 274 is configured to selectively engage the anvil assembly 500 such that axial movement of the trocar member 274 via rotation of the drive screw 276 results in concomitant axial movement of the anvil assembly 500.

[0032] 4, clamp transfer assembly 240 includes a first rotatable proximal drive shaft 212 coupled to one of motors 152a and 152b, a second rotatable proximal drive shaft 281, a rotatable distal drive shaft 282, and a coupling member 286, each of which are supported within outer tube 206 of adapter assembly 200. Clamp transfer assembly 240 functions to extend / retract trocar member 274 of trocar assembly 270 of adapter assembly 200 and to open / close anvil assembly 510 when anvil assembly 510 is connected to trocar member 274.

[0033] Referring to FIG. 5, the adapter assembly 200 includes a stapling transmission assembly 250 for interconnecting the first motor 152a and a second axially translatable drive member of the reload 400, which converts and transmits the rotation of the first motor 152a into axial translation of the outer flexible band assembly 255 of the adapter assembly 200, which in turn transmits the rotation to the staple driver 430 of the reload 400, which fires the staples 423 from the reload 400 against the anvil assembly 510.

[0034] The stapling transmission assembly 250 of the adapter assembly 200 includes an outer flexible band assembly 255 secured to a staple driver coupler 254. The second rotatable proximal drive shaft 220 is coupled to the second motor 152b and configured to actuate the staple driver coupler 254, which converts rotational motion to longitudinal motion. The outer flexible band assembly 255 includes first and second flexible bands 255a, 255b that are laterally spaced apart and connected at their proximal ends to a support ring 255c and at their distal ends to a proximal end of a distal pusher 255d. Each of the first and second flexible bands 255a, 255b is attached to the support ring 255c and the distal pusher 255d. The outer flexible band assembly 255 further includes first and second connecting extensions 255e, 255f extending proximally from the support ring 255c. The first and second connecting extensions 255 e , 255 f are configured to operatively connect the outer flexible band assembly 255 to the staple driver coupler 254 of the stapling transfer assembly 250 .

[0035] The adapter assembly 200 also includes a cut transmission assembly 260 for interconnecting the second motors 152b and the annular knife 444 of the reload 400, which converts and transmits rotation of one of the second motors 152b into axial translation of the outer flexible band assembly 265 of the adapter assembly 200, which in turn causes the knife carrier 442 of the reload 400 to advance the annular knife 444 from the reload 400 towards the anvil assembly 510.

[0036] The inner flexible band assembly 265 includes first and second flexible bands 265a, 265b that are laterally spaced apart and connected at their proximal ends to a support ring 265c and at their distal ends to a proximal end of a support base 265d. Each of the first and second flexible bands 265a, 265b is attached to the support ring 265c and the support base 265d.

[0037] The inner flexible band assembly 265 further includes first and second connecting extensions 265e, 265f extending proximally from the support ring 265c. The first and second connecting extensions 265e, 265f are configured to operably connect the inner flexible band assembly 265 to the knife driver 264 of the cut transmission assembly 260. The support base 265d extends distally from the flexible bands 265a, 265b and is configured to connect with the knife assembly 440 of the reload 400.

[0038] 6, the staple driver 430 of the reload 400 includes a staple cartridge 420 having a driver adapter 432 and a driver 434. A proximal end 432a of the driver adapter 432 is configured for selective contact and abutment with a distal pusher 255d of the outer flexible band assembly 255 of the stapling transfer assembly 250 of the adapter assembly 200. In operation, during distal advancement of the outer flexible band assembly 255, the distal pusher 255d of the outer flexible band assembly 255 contacts the proximal end 432a of the driver adapter 432 to advance the driver adapter 432 and the driver 434 from a first or proximal position to a second or distal position, as described above. The driver 434 includes a plurality of driver members 436 aligned with the staple pockets 421 of the staple cartridge 420 for contact with the staples 423. Thus, advancement of the driver 434 relative to the staple cartridge 420 causes the ejection of the staples 423 from the staple cartridge 420 .

[0039] The knife assembly 440 of the reload 400 includes a knife carrier 442 and an annular knife 444 secured about a distal end 442b of the knife carrier 442. A proximal end 442a of the knife carrier 442 is configured to engage a support base 265d of the inner flexible band assembly. In operation, during distal advancement of the inner flexible band assembly 265, the support base 265d of the inner flexible band assembly 265 connects with the proximal end 442a of the knife carrier 442 to advance the knife carrier 442 and the annular knife 444 from a first or proximal position to a second or advanced position to cause severing of tissue disposed between the staple cartridge 420 and the anvil assembly 510.

[0040] Forces during actuation of the trocar member 274, closure of the end effector 300 (e.g., retraction of the anvil assembly 500 relative to the reload 400), ejection of the staples 423 from the reload 400, and advancement of the knife assembly 440 can be measured by the strain gauges 408b to monitor and control various processes such as firing of the staples 423 from the reload 400, monitor forces during firing and formation of the staples 423 as they are being ejected from the reload 400, optimize formation of the staples 423 (e.g., staple crimp height) as they are being ejected from the reload 400 for different indications of tissue, and monitor and control firing of the annular knife of the reload 400.

[0041] 7, the strain gauge 408b of the adapter assembly 200 is disposed within the strain gauge housing 320. The strain gauge 408b measures and monitors the retraction of the trocar member 274 and the ejection and formation of the staples 423 from the reload 400. During closure of the end effector 300, when the anvil assembly 500 contacts tissue, a passing obstacle, a tissue contacting surface of the reload 400, a staple ejection, etc., a reaction force generally in a distal direction is exerted against the anvil assembly 500. This distally directed reaction force is transmitted from the anvil assembly 500 to the strain gauge 408b. The strain gauge 408b then communicates a signal to the main controller circuit board 142 of the power handle 101 of the handle assembly 100. A graphic is then displayed on the display 146 of the handle assembly 100 to provide the user with real-time information regarding the status of the firing of the handle assembly 100.

[0042] Trocar assembly 270 is axially and rotatably fixed within outer tube 206 of adapter assembly 200. With reference to FIGURE 7, adapter assembly 200 includes a support block 292 fixedly disposed within outer tube 206. A strain gauge housing 320 is disposed between support block 292 and connector sleeve 290. A reload 400 removably couples to connector sleeve 290.

[0043] During operation, the strain gauge 408b of the adapter assembly 200 measures and monitors the retraction of the trocar member 274 which passes through the strain gauge 408b. The strain gauge 408b of the adapter assembly 200 also measures and monitors the ejection of the staples 423 from the reload 400 as the first and second flexible bands 255a, 255b also pass through the strain gauge 408b. During clamping, stapling and severing, a reaction force is exerted against the anvil assembly 500 and the reload 400 which is transferred to the support block 292 which then transfers the reaction force to the strain sensor of the strain gauge 408b.

[0044] The strain sensor of strain gauge 408b may be any device configured to measure strain (a dimensionless quantity) in the object to which it is attached (e.g., support block 292) so that when the object deforms, the metal foil of the strain sensor also deforms, changing its electrical resistance, which is then used to calculate the load experienced by trocar assembly 270. Strain gauge 408b provides closed-loop feedback to the firing / clamping loads presented by the first, second, and third force / rotation transmission / transduction assemblies.

[0045] The strain sensors of the strain gauges 408b then communicate signals to the main controller circuit board 142. The graphics are then displayed on the display 146 of the power pack core assembly 106 of the handle assembly 100 to provide the user with real-time information regarding the firing status of the handle assembly 100. The strain gauges 408b also electrically connect to the electrical connector 312 (FIG. 3) via the proximal harness assembly 314 and the distal harness assembly 316.

[0046] For further details regarding the construction and operation of the circular stapler and its components, reference may be made to International Application No. PCT / US2019 / 040440, filed July 3, 2019, the entire contents of which are incorporated herein by reference.

[0047] 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 on the tissue sandwiched between the reload 400 and the anvil assembly 500 by pressing the bottom portion of the toggle control button 30. During clamping, the anvil assembly 500 is retracted toward the reload 400 until it reaches a preset fully clamped position, i.e., a position of the anvil assembly 500 where the tissue is fully clamped between the anvil assembly 500 and the reload 400. The preset fully clamped position varies for each of the different types of reloads. During clamping, the strain gauge 408b continuously provides measurements to the main controller 147 regarding the force applied to the trocar member 274 as the trocar member 274 moves the anvil assembly 500 to clamp the tissue between the anvil assembly 500 and the reload 400.

[0048] A user begins a surgical procedure by positioning the adapter assembly 200, including the trocar member 274 and the anvil assembly 510, within the colorectum or upper gastrointestinal region. The user presses the toggle control button 30 to extend the trocar member 274 until it penetrates tissue. After extension of the trocar member 274, the anvil assembly 510, previously positioned by the surgeon, is attached to the trocar member 274, and the user begins the clamping process on the tissue clamped between the reload 400 and the anvil assembly 510 by pressing the bottom portion of the toggle control button 30. Once clamping is successfully completed, the user begins the stapling sequence.

[0049] To initiate a stapling sequence, the user presses one of the safety buttons 36 on the power handle 101, which acts as a safety and enables the toggle control button 30 to begin stapling. When the safety button 36 is actuated, a rotation verification calibration check is performed. The display 146 transitions to a stapling sequence display including a circle, progress bar and staple icons showing an animated representation of a circular anastomosis. The stapling sequence screen is displayed until the user initiates a stapling sequence, terminates a stapling sequence, or releases a clamp.

[0050] To initiate a stapling sequence, the user presses the toggle control button 30, which causes the stapling transfer assembly 250 to move, converting rotation to linear motion to eject and form the staples 423 from the circular reload 400. In particular, during the firing sequence, the first motor 152a advances the driver 434 using the stapling transfer assembly 250. The force applied to the stapling transfer assembly 250 is monitored by the strain gauge 408b. When the stapling transfer assembly 250 reaches a target staple position that corresponds to the staple stroke information stored on the storage device 402 of the reload 400 and the force compensation factor detected by the strain gauge 408b, the process is considered complete. This indicates that the staples 423 have been successfully ejected and deformed against the anvil assembly 510.

[0051] FIG. 8 illustrates generally the travel distance and speed of the first motor 152a when advancing the staple driver 434 within the reload 400, and FIG. 9 illustrates a method for advancing the staple driver 434. Although the method of FIG. 9 is described with respect to a circular stapler, the stapling method according to the present disclosure may be incorporated into any powered stapler, including linear staplers. The staple driver 434 is initially advanced at a first speed from a first position 608 (e.g., a hard stop) for a first segment from the first position 608 to a second position 610 (e.g., a base position where the staple driver 434 contacts the staple 423). From the second position 610, the staple driver 434 advances at a second speed slower than the first speed until the staple driver 434 reaches a third position 612 (e.g., a target staple position), expelling the staple 423.

[0052] After reaching the second position 610, the first motor 152a operates at a second, slower speed to eject the staples 423 from the reload 400. During the second segment, as the staples 423 are ejected from the reload 400 to staple the tissue, the primary controller 147 continuously monitors the strain measured by the strain gauge assembly 408b and determines whether the force corresponding to the measured strain is between a minimum staple force and a maximum staple force. The range of staple forces may be stored in the storage device 402 of the reload 400 and used by the primary controller 147 during the stapling sequence. A determination of whether the measured force is below the minimum staple force is used to verify that the staples 423 are present in the reload 400. In addition, a low force may also indicate a failure of the strain gauge 408b. If the measured force is below the minimum stapling force, the primary controller 147 sends a signal to the first motor 152a to retract the driver 434 to the second position 610. The primary controller 147 also terminates the stapling sequence and displays a sequence on the display 146 instructing the user to retract the anvil assembly 510. After removing the anvil assembly 510, the user can replace the circular adapter assembly 200 and reload 400 and restart the stapling process.

[0053] If the measured force exceeds the maximum stapling force, which may be approximately 580 lbs, the main controller 147 stops the first motor 152a and displays a sequence on the display 146 instructing the user to end the stapling sequence. However, the user can continue the stapling process without the force limit detection by pressing the toggle control button 30.

[0054] The main controller 147 determines that the stapling process is successfully completed when the first motor 152a reaches a third position 612 associated with the tissue being stapled and the strain measured during this movement is within the minimum and maximum stapling force limits. Upon reaching the third position 612, the first motor 152a is stopped for a preset period of time to ensure the integrity of the staples 423.

[0055] The first motor 152a may be held for a period of about 1 second to about 10 seconds. Holding the tissue in compression immediately after the staples 423 are formed and before proceeding to the next step in the stapling and cutting process reduces the risks associated with rapid movement of the stapling components (e.g., anvil assembly 500 and reload 400). Rapid movement after stapling can sometimes cause the staples 423 to deform due to the rapid release of pressure on the staples 423. Slowing the stapling speed allows the powered surgical stapler 10 to push fluid out of the tissue, resulting in reduced stapling force on the stapling transmission assembly 250 and first motor 152a and reduced force applied to the staples 423, which in turn reduces the likelihood of the staples 423 deforming (e.g., opening).

[0056] Additionally, during the holding period, the strain gauge 408b may measure the strain applied to the staple driver 434 to determine if the strain measurement is not stable, e.g., is increasing. An increase in strain may indicate tissue separation due to poorly formed staples 423. After the holding period expires, the first motor 152a retracts the driver 434 to the fourth position 614 to release pressure on the tissue, and then to the second position 610 before commencing the cutting sequence while the knife assembly 440 advances to cut the stapled tissue.

[0057] It will be understood that various modifications may be made to the embodiments of the disclosed adapter assemblies. Thus, 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 disclosure.

[0058] In one or more examples, 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 codes 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, which corresponds 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).

[0059] 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 foregoing structures, or any other physical structure suitable for implementing the described technology. The technology may also be implemented entirely in one or more circuit or logic elements.

Claims

1. 1. A surgical device comprising: Power supply and a motor coupled to the power source; Reloads containing multiple staples and a transmission assembly movable by said motor; a sensor configured to monitor operation of the transmission assembly and output sensor data; a controller, determining a position of the transmission assembly; operating the motor based on the position of the transfer assembly to advance the transfer assembly and eject the plurality of staples from the reload; a controller configured to stop the motor when the plurality of staples have been ejected from the reload for a preset period of time.

2. The surgical device of claim 1 , wherein the transmission assembly further includes a stapler driver.

3. The surgical device of claim 2 , wherein the sensor includes a strain gauge configured to measure a force applied to the transmission assembly.

4. The surgical device of claim 3, wherein the controller is further configured to operate the motor to advance the staple driver from a first position to a second position at a first speed.

5. 5. The surgical device of claim 4, wherein the controller is further configured to operate the motor to advance the staple driver from the second position to a third position at a second speed slower than the first speed.

6. The surgical device of claim 5 , wherein the controller is further configured to determine that the measured force is within a range having a minimum force threshold and a maximum force threshold.

7. The surgical device of claim 6, wherein the preset period is from about 1 second to about 10 seconds.

8. The surgical device of claim 1 , wherein the controller is further configured to operate the motor to retract the transmission assembly.

9. The surgical device of claim 3 , wherein the controller is further configured to determine the measured force during the preset period of time.

10. The surgical device of claim 9, wherein the controller is further configured to determine whether the plurality of staples are properly formed during the preset period of time.

11. The surgical device of claim 1 , wherein the controller is configured to determine the plurality of staples to be ejected from the reload based on at least one of the positions of the transmission assembly.

12. 1. A method for controlling a powered stapler, the powered stapler comprising: a transmission assembly; a motor coupled to the transmission assembly; and a controller, the transmission assembly including a stapler driver configured to engage a reload, the method comprising: the controller operating the motor; the motor advancing the transmission assembly; the controller determining a position of the transmission assembly; the stapler driver ejecting a plurality of staples from the reload; the controller stopping the motor after the plurality of staples have been ejected from the reload for a preset period of time.

13. The method of claim 12, further comprising a strain gauge measuring the force applied to the transmission assembly.

14. The method of claim 13, further comprising the motor advancing the staple driver from a first position to a second position at a first speed.

15. The method of claim 14, further comprising the motor advancing the staple driver from the second position to a third position at a second speed slower than the first speed.

16. The method of claim 15, further comprising the controller determining that the measured force is within a range having a minimum force threshold and a maximum force threshold.

17. The method of claim 16, wherein the motor is stopped for about 1 second to about 10 seconds.

18. The method of claim 12, further comprising the motor retracting the transmission assembly after releasing the plurality of staples from the reload.

19. The method of claim 13, further comprising the strain gauge measuring the force applied to the transmission assembly during the predetermined period.

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