Patent Publication Number: US-2021177423-A1

Title: Handheld electromechanical surgical system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/972,606 filed May 7, 2018, which claims the benefit of and priority to U.S. Provisional Patent Application No. 62/517,276 filed Jun. 9, 2017 and U.S. Provisional Patent Application No. 62/517,297 filed Jun. 9, 2017. The entire disclosures of all of the foregoing applications are incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to surgical devices. More specifically, the present disclosure relates to handheld electromechanical surgical systems for performing surgical procedures. 
     2. Background of Related Art 
     One type of surgical device is a circular clamping, cutting and stapling device. Such a device may be employed in a surgical procedure to reattach rectum portions that were previously transected, or similar procedures. Conventional circular clamping, cutting and stapling instruments include a pistol or linear grip-styled structure having an elongated shaft extending therefrom and a staple cartridge supported on the distal end of the elongated shaft. In this instance, a physician may insert an anvil assembly of the circular stapling instrument into a rectum of a patient and maneuver the anvil assembly up the colonic tract of the patient toward the transected rectum portions. The physician may also insert the remainder of the circular stapling instrument (including the cartridge assembly) through an incision and toward the transected rectum portions. The anvil and cartridge assemblies are approximated toward one another and staples are ejected from the cartridge assembly toward the anvil assembly to form the staples in tissue to affect an end-to-end anastomosis, and an anular knife is fired to core a portion of the clamped tissue portions. After the end-to-end anastomosis has been effected, the circular stapling apparatus is removed from the surgical site. 
     A number of surgical device manufacturers have developed product lines with proprietary powered drive systems for operating and/or manipulating the surgical device. In many instances the surgical devices include a powered handle assembly, which is reusable, and a disposable staple cartridge assembly, end effector or the like that is selectively connected to the powered handle assembly prior to use and then disconnected from the staple cartridge assembly or end effector following use in order to be disposed of or in some instances sterilized for re-use. 
     The use of powered electro and endomechanical surgical staplers, including intelligent battery power, has grown tremendously over the past few decades. Advanced technology and informatics within these intelligent battery-powered stapling devices provide the ability to gather clinical data and drive design improvements to ultimately improve patient outcomes. Accordingly, a need exists for improved powered electro and endomechanical surgical staplers that are capable of evaluating conditions that affect staple formation with the intention of building a more intelligent stapling algorithm. 
     SUMMARY 
     A handheld electromechanical surgical system provided in accordance with aspects of the present disclosure is configured for selective connection with a surgical reload in order to actuate the surgical reload to perform at least one function, the surgical reload including an annular staple pusher for firing an annular array of staples thereof, and a circular knife carrier for translating an annular knife independently of the staple pusher. 
     The surgical system provided in accordance with the present disclosure includes a handheld electromechanical surgical device including a device housing; and at least one rotatable drive shaft supported in and projecting from the device housing. 
     The surgical system provided in accordance with the present disclosure includes an adapter assembly selectively connectable between the housing of the surgical device and the surgical reload. The adapter assembly includes an adapter housing configured and adapted for connection with the surgical device and to be in operative communication with each rotatable drive shaft of the surgical device; an outer tube having a proximal end supported by the adapter housing and a distal end configured and adapted for connection with the surgical reload, wherein the distal end of the outer tube is in operative communication with each of the annular staple pusher and the circular knife carrier of the surgical reload; a trocar assembly supported within the outer tube, the trocar assembly including a trocar member threadably supported on a distal end of a trocar drive screw; and a first force/rotation transmitting/converting assembly for interconnecting a respective one drive shaft of the surgical device and the trocar drive screw of the trocar assembly. 
     The first force/rotation transmitting/converting assembly includes a first proximal rotation receiving member that is connectable to a respective rotatable drive shaft of the surgical device; and a first distal force transmitting member that is connected to the trocar drive screw of the trocar assembly, the first distal force transmitting member being non-rotatably connected to the first proximal rotation receiving member; 
     The adapter assembly includes at least a second force/rotation transmitting/converting assembly for interconnecting a respective one drive shaft of the surgical device and a respective one of the annular staple pusher and the circular knife carrier of the surgical reload. The second force/rotation transmitting/converting assembly includes a second proximal rotation receiving member that is connectable to a respective rotatable drive shaft of the surgical device; and a second distal force transmitting member that is connectable to the respective one of the annular staple pusher and the circular knife carrier of the surgical reload, the second distal force transmitting member being connected to the second proximal rotation receiving member in such a manner whereby rotation of the second proximal rotation receiving member is converted to axial translation of the second distal force transmitting member, and in turn, axial translation of the respective one of the annular staple pusher and the circular knife carrier of the surgical reload. 
     The trocar member of the trocar assembly may be keyed against rotation relative to the outer tube as the trocar drive screw is rotated. 
     The first force/rotation transmitting/converting assembly may further include a rotatable proximal drive shaft non-rotatably connected to the first proximal rotation receiving member; and a rotatable distal drive shaft non-rotatably interconnecting the rotatable proximal drive shaft and the first distal force transmitting member. 
     The rotatable distal drive shaft may be pivotably connected to each of the rotatable proximal drive shaft and the first distal force transmitting member. 
     Rotation of the rotatable drive shaft of the surgical device, associated with the first force/rotation transmitting/converting assembly, may result in axial translation of the trocar member of the trocar assembly. 
     The surgical system may further include an anvil assembly having an annular head assembly pivotably supported on a distal end of an anvil rod assembly, wherein the anvil rod assembly is selectively connectable to a tip of the trocar member. 
     When the anvil assembly is connected to the trocar member, rotation of the rotatable drive shaft of the surgical device, associated with the first force/rotation transmitting/converting assembly, may result in an axial translation of the annular head assembly relative to the surgical reload. 
     The annular head assembly may be axially translatable between a fully extended position and a fully retracted position, relative to the surgical reload, and any position therebetween. 
     The at least a second force/rotation transmitting/converting assembly may include a second force/rotation transmitting/converting assembly, and a third force/rotation transmitting/converting assembly. The second force/rotation transmitting/converting assembly may be operatively associated with the annular staple pusher of the surgical reload such that actuation of the second force/rotation transmitting/converting assembly results in distal actuation of the annular staple pusher. The third force/rotation transmitting/converting assembly may be operatively associated with the circular knife carrier of the surgical reload such that actuation of the third force/rotation transmitting/converting assembly results in distal actuation of the circular knife carrier. 
     The second force/rotation transmitting/converting assembly may include a gear train actuatable by the second proximal rotation receiving member; a lead screw operatively connected to the gear train, wherein actuation of the gear train results in rotation of the lead screw; a driver threadably connected to the lead screw, wherein rotation of the lead screw results in axial translation of the driver; a flexible band assembly secured to the driver, wherein the flexible band assembly includes a pair of spaced apart flexible bands; and a support base secured to a distal end of the pair of flexible bands. 
     The support base of the second force/rotation transmitting/converting assembly may be operatively associated with the annular staple pusher of the surgical reload such that actuation of the respective rotatable drive shaft of the surgical device results in distal actuation of the annular staple pusher of the surgical reload. 
     The third force/rotation transmitting/converting assembly may include a gear train actuatable by a third proximal rotation receiving member; a lead screw operatively connected to the gear train of the third force/rotation transmitting/converting assembly, wherein actuation of the gear train of the third force/rotation transmitting/converting assembly results in rotation of the lead screw of the third force/rotation transmitting/converting assembly; a driver threadably connected to the lead screw of the third force/rotation transmitting/converting assembly, wherein rotation of the lead screw of the third force/rotation transmitting/converting assembly results in axial translation of the driver of the third force/rotation transmitting/converting assembly; a flexible band assembly secured to the driver of the third force/rotation transmitting/converting assembly, wherein the flexible band assembly of the third force/rotation transmitting/converting assembly includes a pair of spaced apart flexible bands; and a support base secured to a distal end of the pair of flexible bands of the third force/rotation transmitting/converting assembly. 
     The support base of the third force/rotation transmitting/converting assembly may be operatively associated with the circular knife carrier of the surgical reload such that actuation of the respective rotatable drive shaft of the surgical device results in distal actuation of the circular knife carrier of the surgical reload. 
     The pair of flexible bands of the third force/rotation transmitting/converting assembly may be disposed inward of the pair of flexible bands of the second force/rotation transmitting/converting assembly. 
     The gear train of the second force/rotation transmitting/converting assembly may be disposed proximally of the gear train of the third force/rotation transmitting/converting assembly. 
     The first force/rotation transmitting/converting assembly may extend through the gear train of the second force/rotation transmitting/converting assembly and through the gear train of the third force/rotation transmitting/converting assembly. 
     The gear train of each of the second and third force/rotation transmitting/converting assemblies may be a planetary gear system. 
     The adapter assembly may further include a strain gauge assembly supported within the outer tube, wherein the strain gauge assembly is operatively associated with the trocar member of the trocar assembly. 
     The strain gauge assembly may sense axial translation of the trocar member. 
     The handheld electromechanical surgical device may include a battery, a circuit board powered by the battery, and an electrical display connected to each of the battery and the circuit board. The strain gauge assembly may be connected to the circuit board when the adapter assembly is connected to the housing of the handheld electromechanical surgical device. 
     The display of the handheld electromechanical surgical device may display forces exerted on the trocar member as measured by the strain gauge assembly. 
     The display of the handheld electromechanical surgical device may display an axial position of the trocar member relative to the surgical reload. 
     The display of the handheld electromechanical surgical device may display a gap distance between the annular head assembly and the surgical reload. 
     The display of the handheld electromechanical surgical device may display a firing of an annular array of staples of the surgical reload as the annular staple pusher is axially advanced. 
     The display of the handheld electromechanical surgical device may display an actuation of a knife of the surgical reload as the circular knife carrier is axially advanced. 
     According to a further aspect of the present disclosure, an adapter assembly for interconnecting a handheld surgical device of an electromechanical surgical system and a surgical reload is provided. The adapter assembly includes an adapter housing configured and adapted for connection with the handheld surgical device and to be in operative communication with each rotatable drive shaft of the surgical device; an outer tube having a proximal end supported by the adapter housing and a distal end configured and adapted for connection with the surgical reload, wherein the distal end of the outer tube is in operative communication with each of an annular staple pusher and a circular knife carrier of the surgical reload; a trocar assembly supported within the outer tube, the trocar assembly including a trocar member threadably supported on a distal end of a trocar drive screw; and a first force/rotation transmitting/converting assembly for interconnecting a respective one drive shaft of the surgical device and the trocar drive screw of the trocar assembly. 
     The first force/rotation transmitting/converting assembly includes a first proximal rotation receiving member that is connectable to a respective rotatable drive shaft of the surgical device; and a first distal force transmitting member that is connected to the trocar drive screw of the trocar assembly, the first distal force transmitting member being non-rotatably connected to the first proximal rotation receiving member; 
     At least a second force/rotation transmitting/converting assembly is provided for interconnecting a respective one drive shaft of the surgical device and a respective one of the annular staple pusher and the circular knife carrier of the surgical reload. The second force/rotation transmitting/converting assembly includes a second proximal rotation receiving member that is connectable to a respective rotatable drive shaft of the surgical device; and a second distal force transmitting member that is connectable to the respective one of the annular staple pusher and the circular knife carrier of the surgical reload, the second distal force transmitting member being connected to the second proximal rotation receiving member in such a manner whereby rotation of the second proximal rotation receiving member is converted to axial translation of the second distal force transmitting member, and in turn, axial translation of the respective one of the annular staple pusher and the circular knife carrier of the surgical reload. 
     The trocar member of the trocar assembly may be keyed against rotation relative to the outer tube as the trocar drive screw is rotated. 
     The first force/rotation transmitting/converting assembly may further include a rotatable proximal drive shaft non-rotatably connected to the first proximal rotation receiving member; and a rotatable distal drive shaft non-rotatably interconnecting the rotatable proximal drive shaft and the first distal force transmitting member. 
     The rotatable distal drive shaft may be pivotably connected to each of the rotatable proximal drive shaft and the first distal force transmitting member. 
     Rotation of the rotatable drive shaft of the surgical device, associated with the first force/rotation transmitting/converting assembly, may result in axial translation of the trocar member of the trocar assembly. 
     The adapter assembly may further include an anvil assembly having an annular head assembly pivotably supported on a distal end of an anvil rod assembly, wherein the anvil rod assembly is selectively connectable to a tip of the trocar member. 
     When the anvil assembly is connected to the trocar member, rotation of the rotatable drive shaft of the surgical device, associated with the first force/rotation transmitting/converting assembly, may result in an axial translation of the annular head assembly relative to the surgical reload. 
     The annular head assembly may be axially translatable between a fully extended position and a fully retracted position, relative to an attached surgical reload, and any position therebetween. 
     The at least a second force/rotation transmitting/converting assembly may include a second force/rotation transmitting/converting assembly, and a third force/rotation transmitting/converting assembly. The second force/rotation transmitting/converting assembly may be operatively associated with the annular staple pusher of the surgical reload such that actuation of the second force/rotation transmitting/converting assembly results in distal actuation of the annular staple pusher. The third force/rotation transmitting/converting assembly may be operatively associated with the circular knife carrier of the surgical reload such that actuation of the third force/rotation transmitting/converting assembly results in distal actuation of the circular knife carrier. 
     The second force/rotation transmitting/converting assembly may include a gear train actuatable by the second proximal rotation receiving member; a lead screw operatively connected to the gear train, wherein actuation of the gear train results in rotation of the lead screw; a driver threadably connected to the lead screw, wherein rotation of the lead screw results in axial translation of the driver; a flexible band assembly secured to the driver, wherein the flexible band assembly includes a pair of spaced apart flexible bands; and a support base secured to a distal end of the pair of flexible bands. 
     The support base of the second force/rotation transmitting/converting assembly may be operatively associated with the annular staple pusher of the surgical reload such that actuation of the respective rotatable drive shaft of the surgical device results in distal actuation of the annular staple pusher of the surgical reload. 
     The third force/rotation transmitting/converting assembly may include a gear train actuatable by a third proximal rotation receiving member; a lead screw operatively connected to the gear train of the third force/rotation transmitting/converting assembly, wherein actuation of the gear train of the third force/rotation transmitting/converting assembly results in rotation of the lead screw of the third force/rotation transmitting/converting assembly; a driver threadably connected to the lead screw of the third force/rotation transmitting/converting assembly, wherein rotation of the lead screw of the third force/rotation transmitting/converting assembly results in axial translation of the driver of the third force/rotation transmitting/converting assembly; a flexible band assembly secured to the driver of the third force/rotation transmitting/converting assembly, wherein the flexible band assembly of the third force/rotation transmitting/converting assembly includes a pair of spaced apart flexible bands; and a support base secured to a distal end of the pair of flexible bands of the third force/rotation transmitting/converting assembly. 
     The support base of the third force/rotation transmitting/converting assembly may be operatively associated with the circular knife carrier of the surgical reload such that actuation of the respective rotatable drive shaft of the surgical device results in distal actuation of the circular knife carrier of the surgical reload. 
     The pair of flexible bands of the third force/rotation transmitting/converting assembly may be disposed inward of the pair of flexible bands of the second force/rotation transmitting/converting assembly. 
     The gear train of the second force/rotation transmitting/converting assembly may be disposed proximally of the gear train of the third force/rotation transmitting/converting assembly. 
     The first force/rotation transmitting/converting assembly may extend through the gear train of the second force/rotation transmitting/converting assembly and through the gear train of the third force/rotation transmitting/converting assembly. 
     The gear train of each of the second and third force/rotation transmitting/converting assemblies may be a planetary gear system. 
     The adapter assembly may further include a strain gauge assembly supported within the outer tube, wherein the strain gauge assembly is operatively associated with the trocar member of the trocar assembly. 
     The strain gauge assembly may sense axial translation of the trocar member. 
     The strain gauge assembly may be connected to a circuit board of the surgical device when the adapter assembly is connected to the surgical device. 
     The strain gauge assembly may be configured to measure forces exerted on the trocar, and wherein the forces are displayed on a display of the surgical device. 
     An axial position of the trocar member relative to the surgical reload may be displayed on a display of the surgical device. 
     A gap distance between the annular head assembly of the anvil assembly and the surgical reload may be displayed on a display of the surgical device. 
     A firing of an annular array of staples of the surgical reload as the annular staple pusher is axially advanced may be displayed on a display of the surgical device. 
     An actuation of a knife of the surgical reload as the circular knife carrier is axially advanced may be displayed on a display of the surgical device. 
     According to one embodiment of the present disclosure, a surgical device includes: an adapter assembly having a first storage device; an end effector configured to couple to a distal portion of the adapter assembly, the end effector including a second storage device; and a handle assembly configured to couple to a proximal portion of the adapter assembly. The handle assembly includes: a power source; a motor coupled to the power source, the motor configured to actuate at least one of the adapter assembly or the end effector; and a controller configured to communicate with the first and second storage devices. 
     According to one aspect of the above embodiment, the controller is operatively coupled to the motor and configured to calibrate the motor while at least one of the adapter assembly or the end effector is actuated by the motor. 
     According to another aspect of the above embodiment, the controller is configured to read and write data onto the first and second storage devices. The data may include usage counts. 
     According to a further aspect of the above embodiment, the controller is configured to write a recovery code onto the second storage device. 
     According to one aspect of the above embodiment, the handle assembly includes a memory accessible by the controller. The controller may be configured to write the recovery code onto the memory. 
     According to another aspect of the above embodiment, at least one of the adapter assembly or the handle assembly is replaceable during a surgical procedure and at least one of the adapter assembly or the handle assembly is configured to resume the surgical procedure based on the recovery code. 
     According to another embodiment of the present disclosure, a surgical device includes: a handle assembly having a power source; a motor coupled to the power source; and a controller configured to control the motor. The surgical device also includes an adapter assembly configured to selectively couple to the handle assembly; a reload configured to selectively couple to a distal portion of the adapter assembly, the reload including a plurality of fasteners; and an anvil assembly selectively couplable to the distal portion of the adapter assembly. The anvil assembly being movable relative to the reload, wherein the controller is configured to control the motor to move the anvil thereby compressing tissue between the anvil and the reload at first speed for a first segment and at a second speed for a second segment, the second speed being slower than the first speed. 
     According to one aspect of the above embodiment, the adapter assembly includes a strain gauge configured to measure strain. 
     According to another aspect of the above embodiment, the controller is further configured to determine whether the anvil assembly is decoupled from the adapter assembly based on the measured strain during the second segment. 
     According to a further aspect of the above embodiment, the controller is further configured to move the anvil at a variable speed during a third segment. 
     According to yet another aspect of the above embodiment, the controller is further configured to determine a predicted clamping force based on a plurality of measured strain values. 
     According to one aspect of the above embodiment, the controller is further configured to calculate the predicted clamping force from the plurality of measured strain values using a second-order predictive filter. 
     According to another aspect of the above embodiment, the controller is further configured to adjust the variable speed based on a comparison of the predicted clamping force and a target clamping force. 
     According to a further aspect of the above embodiment, the controller is further configured to calculate a set speed during the third segment based on a difference between the target clamping force and the predicted clamping force. 
     According to a further embodiment of the present disclosure, a surgical device includes: a handle assembly having: a power source; at least one motor coupled to the power source; and a controller configured to control the motor. The surgical device also includes: an adapter assembly configured to selectively couple to the handle assembly, the adapter assembly including a strain gauge configured to measure strain; a reload configured to selectively couple to a distal portion of the adapter assembly. The reload includes: a plurality of fasteners; an annular staple pusher for ejecting the plurality of staples; and an anvil assembly selectively couplable to the distal portion of the adapter assembly, the anvil assembly being movable relative to the reload; wherein the controller is configured to control the motor to move the annular staple pusher based on the measured strain. 
     According to one aspect of the above embodiment, the controller is configured to compare the measured strain to a minimum stapling force and a maximum stapling force during movement of the annular staple pusher. 
     According to another aspect of the above embodiment, the controller is configured to determine presence of the plurality of fasteners based on the measured strain being below the minimum stapling force. 
     According to a further aspect of the above embodiment, the controller is configured to stop the motor in response to the measured strain exceeding the maximum stapling force. 
     According to yet another aspect of the above embodiment, the reload further includes a circular knife independently movable relative to the staple pusher. 
     According to one aspect of the above embodiment, the controller is configured to control the motor to move the circular knife based on the measured strain. 
     According to another aspect of the above embodiment, the controller is configured to compare the measured strain to a target cutting force and a maximum cutting force during movement of the circular knife. 
     According to a further aspect of the above embodiment, the controller is configured to determine whether tissue was cut based on the measured strain being equal to or exceeding the target cutting force. 
     According to one embodiment of the above embodiment, a method of using a surgical device includes: coupling an adapter assembly to a handle assembly, the adapter assembly including a storage device and the handle assembly including a motor, a memory, and a controller; executing an operational sequence by the controller to control the motor to actuate at least one component of the adapter assembly; and registering an error state associated with the operational sequence. The method also includes writing a recovery code in the storage device and the memory; replacing at least one of the adapter assembly or the handle assembly based on the error state; and resuming the operational sequence based on the recovery code read from at least one of the storage device or the memory. 
     According to one aspect of the above embodiment, the method further includes coupling a reload including a plurality of fasteners to a distal portion of the adapter assembly. 
     According to another aspect of the above embodiment, the method further includes coupling an anvil assembly to the distal portion of the adapter assembly. 
     According to a further aspect of the above embodiment, the method further includes displaying a recovery procedure for resuming the operational sequence on a display of the handle assembly. 
     According to another embodiment of the present disclosure, a method of using a surgical device includes: coupling an adapter assembly to a handle assembly; performing a surgical procedure using the handle assembly and adapter assembly; replacing at least one of the adapter assembly or the handle assembly upon encountering an error in at least one of the adapter assembly or the handle assembly; and resuming the surgical procedure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a handheld surgical device and adapter assembly, in accordance with an embodiment of the present disclosure, illustrating a connection thereof with an end effector or reload; 
         FIG. 2  is a front perspective view of a handle assembly of the surgical device of  FIG. 1 ; 
         FIG. 3  is a front, perspective view, with parts separated, of the handle assembly of  FIG. 2 ; 
         FIG. 4  is a rear, perspective view, with parts separated, of the handle assembly of  FIG. 2 ; 
         FIG. 5  is a perspective view illustrating an insertion of the handle assembly into an outer shell housing assembly, in accordance with the present disclosure; 
         FIG. 6  is a perspective view illustrating the handle assembly inserted in a proximal half-section of the outer shell housing assembly, in accordance with the present disclosure; 
         FIG. 7  is a side, elevational view of the outer shell housing, shown in an open condition; 
         FIG. 8  is a front, perspective view of the outer shell housing, shown in an open condition; 
         FIG. 9  is a front, perspective view of the outer shell housing, shown in a partially open condition, and with an insertion guide removed therefrom; 
         FIG. 10  is a rear, perspective view of the insertion guide; 
         FIG. 11  is a front, perspective view of the insertion guide; 
         FIG. 12  is a front, perspective view of a power handle with an inner rear housing separated therefrom; 
         FIG. 13  is a rear, perspective view of the power handle with the inner rear housing removed therefrom; 
         FIG. 14  is a perspective view of a power handle core assembly of the power handle; 
         FIG. 15  is a front, perspective view of a motor assembly and a control assembly of the power handle core assembly of  FIG. 14 ; 
         FIG. 16  is a rear, perspective view, with parts separated, of the motor assembly and the control assembly of  FIG. 15 ; 
         FIG. 17  is a longitudinal, cross-sectional view of the handle assembly of  FIG. 2 ; 
         FIG. 18  is an enlarged view of the indicated area of detail of  FIG. 17 ; 
         FIG. 19  is a cross-sectional view of the handle assembly as taken through  19 - 19  of  FIG. 17 ; 
         FIG. 20  is a front, perspective view of the adapter assembly of  FIG. 1 ; 
         FIG. 21  is a rear, perspective view of the adapter assembly of  FIGS. 1 and 20 ; 
         FIG. 22  is a perspective view illustrating a connection of the adapter assembly and the handle assembly; 
         FIG. 23  is a perspective view of the adapter assembly, illustrating a reload secured to a distal end thereof; 
         FIG. 24  is a perspective view of the adapter assembly without the reload secured to the distal end thereof; 
         FIG. 25  is a perspective view of the adapter assembly, shown partially in phantom, illustrating a first force/rotation transmitting/converting assembly thereof; 
         FIG. 26  is a perspective view of the first force/rotation transmitting/converting assembly of  FIG. 25 ; 
         FIG. 27  is a longitudinal, cross-sectional view of a first rotatable proximal drive shaft, a first rotatable distal drive shaft and a coupling member of the first force/rotation transmitting/converting assembly of  FIG. 25 ; 
         FIG. 28  is a perspective view, with parts separated, of a trocar assembly of the first force/rotation transmitting/converting assembly of  FIG. 25 ; 
         FIG. 29  is a perspective view, of a distal end portion of the first force/rotation transmitting/converting assembly of  FIG. 25 , illustrating a support block thereof; 
         FIG. 30  is a perspective view, of a distal end portion of the first force/rotation transmitting/converting assembly of  FIG. 25 , with the support block thereof shown in phantom; 
         FIG. 31  is a cross-sectional view as taken through  31 - 31  of  FIG. 29 ; 
         FIG. 32  is a cross-sectional view as taken through  32 - 32  of  FIG. 29 ; 
         FIG. 33  is a cross-sectional view as taken through  33 - 33  of  FIG. 32 ; 
         FIG. 34  is a perspective view of the adapter assembly, shown partially in phantom, illustrating a second force/rotation transmitting/converting assembly thereof; 
         FIG. 35  is a perspective view of the second force/rotation transmitting/converting assembly of  FIG. 34 ; 
         FIG. 36  is an enlarged view of the indicated area of detail of  FIG. 35 ; 
         FIG. 37  is a perspective view, with parts separated, of a planetary gear set and staple driver, of the second force/rotation transmitting/converting assembly of  FIG. 34 ; 
         FIG. 38  is a cross-sectional view as taken through  38 - 38  of  FIG. 24 ; 
         FIG. 39  is a perspective view of the adapter assembly, shown partially in phantom, illustrating a third force/rotation transmitting/converting assembly thereof; 
         FIG. 40  is a perspective view of the third force/rotation transmitting/converting assembly of  FIG. 39 ; 
         FIG. 41  is an enlarged view of the indicated area of detail of  FIG. 40 ; 
         FIG. 42  is a perspective view, with parts separated, of a planetary gear set and knife driver, of the third force/rotation transmitting/converting assembly of  FIG. 39 ; 
         FIG. 43  is a perspective view of a distal portion of the adapter assembly; 
         FIG. 44  is a further perspective view, with parts separated, of a distal portion of the adapter assembly; 
         FIG. 45  is a rear, perspective view of the internal components of the distal end portion of the adapter assembly; 
         FIG. 46  is an enlarged view of the indicated area of detail of  FIG. 45 ; 
         FIG. 47  is a front, perspective view of the internal components of the distal end portion of the adapter assembly; 
         FIG. 48  is an enlarged view of the indicated area of detail of  FIG. 47 ; 
         FIG. 49  is a front, perspective view of the internal components of a more distal end portion of the adapter assembly of  FIGS. 45-48 ; 
         FIG. 50  is a front, perspective view, with parts separated, of the internal components of the more distal end portion of the adapter assembly of  FIG. 49 ; 
         FIG. 51  is a perspective view, with parts separated, of the distal end portion of the adapter assembly of  FIGS. 45-50 ; 
         FIG. 52  is a perspective view of the distal end portion of the adapter assembly of  FIGS. 45-51 , illustrating an electrical assembly thereof; 
         FIG. 53  is a perspective view of the electrical assembly of the adapter assembly of the present disclosure; 
         FIG. 54  is a perspective view of a strain gauge assembly of the electrical assembly of  FIGS. 52-53 ; 
         FIG. 55  is a cross-sectional view, as taken through  55 - 55  of  FIG. 54 ; 
         FIG. 56  is a longitudinal, cross-sectional view of the more distal end portion of the adapter assembly illustrated in  FIGS. 49 and 50 ; 
         FIG. 57  is a longitudinal, cross-sectional view of a knob assembly of the adapter assembly of the present disclosure; 
         FIG. 58  is a perspective view of a rotation assembly of the knob assembly; 
         FIG. 59  is a longitudinal, cross-sectional view of the rotation assembly of  FIG. 58 ; 
         FIG. 60  is a perspective, partial cross-sectional view, with parts separated, of the rotation assembly of  FIG. 58 ; 
         FIG. 61  is a perspective view of the rotation assembly, illustrating an operation thereof; 
         FIG. 62  is a rear, perspective view of the adapter assembly, illustrating a rotation of the rotation assembly and a shaft assembly relative to a drive coupling assembly thereof; 
         FIG. 63  is a rear, perspective view of the adapter assembly, illustrating the adapter assembly in a non-rotated position thereof; 
         FIG. 64  is a cross-sectional view, as taken through  64 - 64  of  FIG. 63 ; 
         FIG. 65  is a cross-sectional view, as taken through  64 - 64  of  FIG. 63 , illustrating the rotation of the rotation assembly and the shaft assembly relative to the drive coupling assembly; 
         FIG. 66  is a perspective view, with parts separated, of a reload according to the present disclosure; 
         FIG. 67  is a longitudinal, cross-sectional view of the assembled reload of  FIG. 66 ; 
         FIG. 68  is a perspective view of an electrical connector of the reload of  FIGS. 66-67 ; 
         FIG. 69  is a cross-sectional view, as taken through  69 - 69  of  FIG. 68 ; 
         FIG. 70  is a rear, perspective view of the reload of  FIGS. 66-69 , with a release ring and a retaining ring illustrated separated therefrom; 
         FIG. 71  is a longitudinal, cross-sectional view, illustrating the reload aligned with and separated from the more distal end portion of the adapter assembly; 
         FIG. 72  is a longitudinal, cross-sectional view, illustrating the reload aligned and connected with the more distal end portion of the adapter assembly; 
         FIG. 73  is a front, perspective view of an anvil assembly of the present disclosure; 
         FIG. 74  is a rear, perspective view of the anvil assembly of  FIG. 73 ; 
         FIG. 75  is a perspective view, with parts separated, of the anvil assembly of FIGS. 
         73  and  74 ; 
         FIG. 76  is a rear, perspective view of the reload and more distal end portion of the adapter assembly, illustrating a connection of an irrigation tube thereto; 
         FIG. 77  is a rear, perspective view of the reload and more distal end portion of the adapter assembly, illustrating the irrigation tube separated therefrom; 
         FIG. 78  is an enlarged view of the indicated area of detail of  FIG. 77 ; 
         FIG. 79  is a perspective view of the irrigation tube; 
         FIG. 80  is an enlarged view of the indicated area of detail of  FIG. 79 ; 
         FIG. 81  is an enlarged view of the indicated area of detail of  FIG. 79 ; 
         FIGS. 82A-F  illustrate a flow chart of a method for operating the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; 
         FIG. 83  is a schematic diagram illustrating travel distance and speed of the anvil assembly and a corresponding motor during a clamping sequence performed by the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; 
         FIG. 84  is a schematic diagram illustrating travel distance and speed of the driver and a corresponding motor during a stapling sequence performed by the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; 
         FIG. 85  is a schematic diagram illustrating travel distance and speed of the knife assembly and a corresponding motor during a cutting sequence performed by the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; 
         FIG. 86  illustrates a flow chart of a method for controlled tissue compression algorithm executed by the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; 
         FIGS. 87A-B  illustrate a flow chart of a method for a stapling algorithm executed by the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; 
         FIGS. 88A-B  illustrate a flow chart of a method for a cutting algorithm executed by the handheld surgical device of  FIG. 1  according to an embodiment of the present disclosure; and 
         FIG. 89  is a schematic diagram of the the handheld surgical device, the adapter assembly, and the reload according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of the presently disclosed surgical devices, and adapter assemblies for surgical devices and/or handle assemblies are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein the term “distal” refers to that portion of the adapter assembly or surgical device, or component thereof, farther from the user, while the term “proximal” refers to that portion of the adapter assembly or surgical device, or component thereof, closer to the user. 
     A surgical device, in accordance with an embodiment of the present disclosure, is a handheld surgical device in the form of a powered electromechanical handle assembly configured for selective attachment thereto of a plurality of different reloads, via a plurality of respective adapter assemblies, that are each configured for actuation and manipulation by the powered electromechanical handle assembly. 
     The surgical device includes a handle assembly  100  which is configured for selective connection with an adapter assembly  200 , and, in turn, adapter assembly  200  is configured for selective connection with a selected reload  400  (of a plurality of reloads), which are configured to produce a surgical effect on tissue of a patient. 
     As illustrated in  FIGS. 1-11 , handle assembly  100  includes a power handle  101 , and an outer shell housing  10  configured to selectively receive and encase power handle  101 . Outer shell housing  10  includes a distal half-section  10   a  and a proximal half-section  10   b  pivotably connected to distal half-section  10   a  by a hinge  16  located along an upper edge of distal half-section  10   a  and proximal half-section  10   b . When joined, distal and proximal half-sections  10   a ,  10   b  define a shell cavity  10   c  therein in which power handle  101  is selectively situated. 
     Distal and proximal half-sections  10   a ,  10   b  of shell housing  10  are divided along a plane that traverses a longitudinal axis “X” of adapter assembly  200 . 
     Each of distal and proximal half-sections  10   a ,  10   b  of shell housing  10  includes a respective upper shell portion  12   a ,  12   b , and a respective lower shell portion  14   a ,  14   b . Lower shell portions  14   a ,  14   b  define a snap closure feature  18  for selectively securing lower shell portions  14   a ,  14   b  to one another and for maintaining shell housing  10  in a closed condition. Shell housing  10  includes right-side and left-side snap closure features  18   a  for further securing distal and proximal half-sections  10   a ,  10   b  of shell housing  10  to one another. 
     Distal half-section  10   a  of shell housing  10  defines a connecting portion  20  configured to accept a corresponding drive coupling assembly  210  of Adapter assembly  200 . Specifically, distal half-section  10   a  of shell housing  10  has a recess  20  that receives a portion of drive coupling assembly  210  of Adapter assembly  200  when Adapter assembly  200  is mated to handle assembly  100 . 
     Connecting portion  20  of distal half-section  10   a  defines a pair of axially extending guide rails  20   a ,  20   b  projecting radially inward from inner side surfaces thereof. Guide rails  20   a ,  20   b  assist in rotationally orienting Adapter assembly  200  relative to handle assembly  100  when Adapter assembly  200  is mated to handle assembly  100 . 
     Connecting portion  20  of distal half-section  10   a  defines three apertures  22   a ,  22   b ,  22   c  formed in a distally facing surface thereof and which are arranged in a common plane or line with one another. Connecting portion  20  of distal half-section  10   a  also defines an elongate slot  24  (to contain connector  66 , see  FIG. 3 ) also formed in the distally facing surface thereof. 
     Connecting portion  20  of distal half-section  10   a  further defines a female connecting feature  26  (see  FIG. 2 ) formed in a surface thereof. Female connecting feature  26  selectively engages with a male connecting feature of Adapter assembly  200 , as will be described in greater detail below. 
     Distal half-section  10   a  of shell housing  10  supports a distal facing toggle control button  30 . Toggle control button  30  is capable of being actuated in a left, right, up and down direction upon application of a corresponding force thereto or a depressive force thereto. 
     Distal half-section  10   a  of shell housing  10  supports a right-side pair of control buttons  32   a ,  32   b  (see  FIG. 3 ); and a left-side pair of control button  34   a ,  34   b  (see  FIG. 2 ). Right-side control buttons  32   a ,  32   b  and left-side control buttons  34   a ,  34   b  are capable of being actuated upon application of a corresponding force thereto or a depressive force thereto. 
     Proximal half-section  10   b  of shell housing  10  supports a right-side fire button  36   a  (see  FIG. 3 ) and a left-side fire button  36   b  (see  FIG. 2 ). Right-side fire button  36   a  and left-side fire button  36   b  are capable of being actuated upon application of a corresponding force thereto or a depressive force thereto. 
     Distal half-section  10   a  and proximal half-section  10   b  of shell housing  10  are fabricated from a polycarbonate, and are clear or transparent or may be overmolded. 
     With reference to  FIGS. 5-11 , handle assembly  100  includes an insertion guide  50  that is configured and shaped to seat on and entirely surround a distal facing edge  10   d  ( FIGS. 3 and 9 ) of proximal half-section  10   b . Insertion guide  50  includes a body portion  52  defining a central opening therein, and a hand/finger grip tab  54  extending from a bottom of body portion  52 . 
     In use, when body portion  52  of insertion guide  50  is seated on distal facing edge  10   d  of proximal half-section  10   b , the central opening of insertion guide  50  provides access to shell cavity  10   c  of shell housing  10  for insertion of a non-sterile power handle  101  of handle assembly  100  into proximal half-section  10   b  of sterile shell housing  10 . 
     With reference to  FIGS. 2-4 , shell housing  10  includes a sterile barrier plate assembly  60  selectively supported in distal half-section  10   a . Specifically, sterile barrier plate assembly  60  is disposed behind connecting portion  20  of distal half-section  10   a  and within shell cavity  10   c  of shell housing  10 . Plate assembly  60  includes a plate  62  rotatably supporting three coupling shafts  64   a ,  64   b ,  64   c . Each coupling shaft  64   a ,  64   b ,  64   c  extends from opposed sides of plate  62  and has a tri-lobe transverse cross-sectional profile. Each coupling shaft  64   a ,  64   b ,  64   c  extends through a respective aperture  22   b ,  22   c ,  22   a  of connecting portion  20  of distal half-section  10   a  when sterile barrier plate assembly  60  is disposed within shell cavity  10   c  of shell housing  10 . 
     Plate assembly  60  further includes an electrical connector  66  supported on plate  62 . Electrical connector  66  extends from opposed sides of plate  62 . Each coupling shaft  64   a ,  64   b ,  64   c  extends through respective aperture  22   a ,  22   b ,  22   c  of connecting portion  20  of distal half-section  10   a  of shell housing  10  when sterile barrier plate assembly  60  is disposed within shell cavity  10   c  of shell housing  10 . Electrical connector  66  includes a chip and defines a plurality of contact paths each including an electrical conduit for extending an electrical connection across plate  62 . 
     When plate assembly  60  is disposed within shell cavity  10   c  of shell housing  10 , distal ends of coupling shaft  64   a ,  64   b ,  64   c  and a distal end of pass-through connector  66  are disposed or situated within connecting portion  20  of distal half-section  10   a  of shell housing  10 , and electrically and/or mechanically engage respective corresponding features of Adapter assembly  200 , as will be described in greater detail below. 
     In operation, with a new and/or sterile shell housing  10  in an open configuration (e.g., distal half-section  10   a  separated from proximal half-section  10   b , about hinge  16 ), and with insertion guide  50  in place against the distal edge  10   d  of proximal half-section  10   b  of shell housing  10 , power handle  101  is inserted through the central opening of insertion guide  50  and into shell cavity  10   c  of shell housing  10 . With power handle  101  inserted into shell cavity  10   c  of shell housing  10 , insertion guide  50  is removed from proximal half-section  10   b  and distal half-section  10   a  is pivoted, about hinge  16 , to a closed configuration for shell housing  10 . In the closed configuration, snap closure feature  18  of lower shell portion  14   a  of distal half-section  10   a  engages snap closure feature  18  of lower shell portion  14   b  of proximal half-section  10   b . Also, right-side and left-side snap closure features  18   a  engage to further maintain shell housing  10  in the closed configuration. 
     In operation, following a surgical procedure, snap closure feature  18  of lower shell portion  14   a  of distal half-section  10   a  is disengaged from snap closure feature  18  of lower shell portion  14   b  of proximal half-section  10   b , and right-side and left-side snap closure features  18   a  are disengaged, such that distal half-section  10   a  may be pivoted, about hinge  16 , away from proximal half-section  10   b  to open shell housing  10 . With shell housing  10  open, power handle  101  is removed from shell cavity  10   c  of shell housing  10  (specifically from proximal half-section  10   b  of shell housing  10 ), and shell housing  10  is discarded. 
     Power handle  101  is then disinfected and cleaned. Power handle  101  is not to be submerged and is not to be sterilized. 
     Referring to  FIGS. 3-6  and  FIGS. 12-19 , handle assembly  100  includes a power handle  101 . Power handle  101  includes an inner handle housing  110  having a lower housing portion  104  and an upper housing portion  108  extending from and/or supported on lower housing portion  104 . Lower housing portion  104  and upper housing portion  108  are separated into a distal half-section  110   a  and a proximal half-section  110   b  connectable to distal half-section  110   a  by a plurality of fasteners. When joined, distal and proximal half-sections  110   a ,  110   b  define an inner handle housing  110  having an inner housing cavity  110   c  therein in which a power-pack core assembly  106  is situated. 
     Power-pack core assembly  106  is configured to control the various operations of handle assembly  100 , as will be set forth in additional detail below. 
     Distal half-section  110   a  of inner handle housing  110  defines a distal opening  111   a  therein which is configured and adapted to support a control plate  160  of power-pack core assembly  106 . Control plate  160  of power handle  101  abuts against a rear surface of plate  62  of sterile barrier plate assembly  60  of shell housing  10  when power handle  101  is disposed within shell housing  10 . 
     With reference to  FIG. 12 , distal half-section  110   a  of inner handle housing  110  supports a distal toggle control interface  130  that is in operative registration with distal toggle control button  30  of shell housing  10 . In use, when power handle  101  is disposed within shell housing  10 , actuation of toggle control button  30  exerts a force on toggle control interface  130 . 
     Distal half-section  110   a  of inner handle housing  110  also supports a right-side pair of control interfaces  132   a ,  132   b , and a left-side pair of control interfaces  134   a ,  134   b . In use, when power handle  101  is disposed within shell housing  10 , actuation of one of the right-side pair of control buttons  32   a ,  32   b  or the left-side pair of control button  34   a ,  34   b  of distal half-section  10   a  of shell housing  10  exerts a force on a respective one of the right-side pair of control interfaces  132   a ,  132   b  or the left-side pair of control interfaces  134   a ,  134   b  of distal half-section  110   a  of inner handle housing  110 . 
     In use, control button  30 , right-side fire button  36   a  or the left-side fire button  36   b , the right-side pair of control interfaces  132   a ,  132   b , and the left-side pair of control interfaces  134   a ,  134   b  of distal half-section  110   a  of inner handle housing  110  will be deactived or fail to function unless shell housing  10  has been validated. 
     Proximal half-section  110   b  of inner handle housing  110  defines a right-side control aperture  136   a  and a left-side control aperture  136   b . In use, when power handle  101  is disposed within shell housing  10 , actuation of one of the right-side fire button  36   a  or the left-side fire button  36   b  of proximal half-section  10   b  of shell housing  10  extends the right-side fire button  36   a  or the left-side fire button  36   b  into and across the right-side control aperture  136   a  or the left-side control aperture  136   b  of the proximal half-section  110   b  of inner handle housing  110 . 
     With reference to  FIGS. 12-19 , inner handle housing  110  provides a housing in which power-pack core assembly  106  is situated. Power-pack core assembly  106  includes a battery circuit  140 , a controller circuit board  142  and a rechargeable battery  144  configured to supply power to any of the electrical components of handle assembly  100 . Controller circuit board  142  includes a motor controller circuit board  142   a , a main controller circuit board  142   b , and a first ribbon cable  142   c  interconnecting motor controller circuit board  142   a  and main controller circuit board  142   b.    
     Power-pack core assembly  106  further includes a display screen  146  supported on main controller circuit board  142   b . Display screen  146  is visible through a clear or transparent window  110   d  (see  FIGS. 12 and 17 ) provided in proximal half-section  110   b  of inner handle housing  110 . 
     Power-pack core assembly  106  further includes a first motor  152 , a second motor  154 , and a third motor  156  each electrically connected to controller circuit board  142  and battery  144 . Motors  152 ,  154 ,  156  are disposed between motor controller circuit board  142   a  and main controller circuit board  142   b . Each motor  152 ,  154 ,  156  includes a respective motor shaft  152   a ,  154   a ,  156   a  extending therefrom. Each motor shaft  152   a ,  154   a ,  156   a  has a tri-lobe transverse cross-sectional profile for transmitting rotative forces or torque. 
     Each motor  152 ,  154 ,  156  is controlled by a respective motor controller. The motor controllers are disposed on motor controller circuit board  142   a  and are A3930/31K motor drivers from Allegro Microsystems, Inc. The A3930/31K motor drivers are designed to control a  3 -phase brushless DC (BLDC) motor with N-channel external power MOSFETs, such as the motors  152 ,  154 ,  156 . Each of the motor controllers is coupled to a main controller disposed on the main controller circuit board  142   b . The main controller is also coupled to memory, which is also disposed on the main controller circuit board  142   b . The main controller is an ARM Cortex M4 processor from Freescale Semiconductor, Inc, which includes 1024 kilobytes of internal flash memory. The main controller communicates with the motor controllers through an FPGA, which provides control logic signals (e.g., coast, brake, etc.). The control logic of the motor controllers then outputs corresponding energization signals to their respective motors  152 ,  154 ,  156  using fixed-frequency pulse width modulation (PWM). 
     Each motor  152 ,  154 ,  156  is supported on a motor bracket  148  such that motor shaft  152   a ,  154   a ,  156   a  are rotatably disposed within respective apertures of motor bracket  148 . As illustrated in  FIGS. 16 and 19 , motor bracket  148  rotatably supports three rotatable drive connector sleeves  152   b ,  154   b ,  156   b  that are keyed to respective motor shafts  152   a ,  154   a ,  156   a  of motors  152 ,  154 ,  156 . Drive connector sleeves  152   b ,  154   b ,  156   b  non-rotatably receive proximal ends of respective coupling shaft  64   a ,  64   b ,  64   c  of plate assembly  60  of shell housing  10 , when power handle  101  is disposed within shell housing  10 . Drive connector sleeves  152   b ,  154   b ,  156   b  are each spring biased away from respective motors  152 ,  154 ,  156 . 
     Rotation of motor shafts  152   a ,  154   a ,  156   a  by respective motors  152 ,  154 ,  156  function to drive shafts and/or gear components of Adapter assembly  200  in order to perform the various operations of handle assembly  100 . In particular, motors  152 ,  154 ,  156  of power-pack core assembly  106  are configured to drive shafts and/or gear components of adapter assembly  200  in order to selectively extend/retract a trocar member  274  of a trocar assembly  270  of adapter assembly  200 ; to, open/close reload  400  (when an anvil assembly  510  is connected to trocar member  274  of trocar assembly  270 ), to fire an annular array of staples of reload  400 , and to fire an annular knife  444  of reload  400 . 
     Motor bracket  148  also supports an electrical receptacle  149 . Electrical receptacle  149  is in electrical connection with main controller circuit board  142   b  by a second ribbon cable  142   d . Electrical receptacle  149  defines a plurality of electrical slots for receiving respective electrical contacts or blades extending from pass-through connector  66  of plate assembly  60  of shell housing  10 . 
     In use, when adapter assembly  200  is mated to handle assembly  100 , each of coupling shafts  64   a ,  64   b ,  64   c  of plate assembly  60  of shell housing  10  of handle assembly  100  couples with corresponding rotatable connector sleeves  218 ,  222 ,  220  of adapter assembly  200  (see  FIG. 22 ). In this regard, the interface between corresponding first coupling shaft  64   a  and first connector sleeve  218 , the interface between corresponding second coupling shaft  64   b  and second connector sleeve  222 , and the interface between corresponding third coupling shaft  64   c  and third connector sleeve  220  are keyed such that rotation of each of coupling shafts  64   a ,  64   b ,  64   c  of handle assembly  100  causes a corresponding rotation of the corresponding connector sleeve  218 ,  222 ,  220  of adapter assembly  200 . 
     The mating of coupling shafts  64   a ,  64   b ,  64   c  of handle assembly  100  with connector sleeves  218 ,  222 ,  220  of adapter assembly  200  allows rotational forces to be independently transmitted via each of the three respective connector interfaces. The coupling shafts  64   a ,  64   b ,  64   c  of handle assembly  100  are configured to be independently rotated by respective motors  152 ,  154 ,  156 . 
     Since each of coupling shafts  64   a ,  64   b ,  64   c  of handle assembly  100  has a keyed and/or substantially non-rotatable interface with respective connector sleeves  218 ,  222 ,  220  of adapter assembly  200 , when adapter assembly  200  is coupled to handle assembly  100 , rotational force(s) are selectively transferred from motors  152 ,  154 ,  156  of handle assembly  100  to adapter assembly  200 . 
     The selective rotation of coupling shaft(s)  64   a ,  64   b ,  64   c  of handle assembly  100  allows handle assembly  100  to selectively actuate different functions of reload  400 . As will be discussed in greater detail below, selective and independent rotation of first coupling shaft  64   a  of handle assembly  100  corresponds to the selective and independent extending/retracting of trocar member  274  of adapter assembly  200  and/or the selective and independent opening/closing of reload  400  (when anvil assembly  510  is connected to trocar member  274 ). Also, the selective and independent rotation of third coupling shaft  64   c  of handle assembly  100  corresponds to the selective and independent firing of an annular array of staples of reload  400 . Additionally, the selective and independent rotation of second coupling shaft  64   b  of handle assembly  100  corresponds to the selective and independent firing of an annular knife  444  of reload  400 . 
     With reference to  FIGS. 12-19 , power-pack core assembly  106  further includes a switch assembly  170  supported within distal half-section  110   a  of inner handle housing  110 , at a location beneath and in registration with toggle control interface  130 , the right-side pair of control interfaces  132   a ,  132   b , and the left-side pair of control interfaces  134   a ,  134   b . Switch assembly  170  includes a first set of four push-button switches  172   a - 172   d  arranged around stem  30   a  of toggle control button  30  of outer shell housing  10  when power handle  101  is disposed within outer shell housing  10 . Switch assembly  170  also includes a second pair of push-button switches  174   a ,  174   b  disposed beneath right-side pair of control interfaces  132   a ,  132   b  of distal half-section  110   a  of inner handle housing  110  when power handle  101  is disposed within outer shell housing  10 . Switch assembly  170  further includes a third pair of push-button switches  176   a ,  176   b  disposed beneath left-side pair of control interfaces  134   a ,  134   b  of distal half-section  110   a  of inner handle housing  110  when power handle  101  is disposed within outer shell housing  10 . 
     Power-pack core assembly  106  includes a single right-side push-button switch  178   a  disposed beneath right-side control aperture  136   a  of proximal half-section  110   b  of inner handle housing  110 , and a single left-side push-button switch  178   b  disposed beneath left-side control aperture  136   b  of proximal half-section  110   b  of inner handle housing  110 . Push-button switches  178   a ,  178   b  are supported on controller circuit board  142 . Push-button switches  178   a ,  178   b  are disposed beneath right-side fire button  36   a  and left-side fire button  36   b  of proximal half-section  10   b  of shell housing  10  when power handle  101  is disposed within outer shell housing  10 . 
     The actuation of push button switch  172   c  of switch assembly  170  of power handle  101 , corresponding to a downward actuation of toggle control button  30 , causes controller circuit board  142  to provide appropriate signals to motor  152  to activate, to retract a trocar member  274  of adapter assembly  200  and/or to close handle assembly  100  (e.g., approximate anvil assembly  510  relative to reload  400 ). 
     The actuation of push button switch  172   a  of switch assembly  170  of power handle  101 , corresponding to an upward actuation of toggle control button  30 , causes controller circuit board  142  to activate, to advance trocar member  274  of adapter assembly  200  and/or to open handle assembly  100  (e.g., separate anvil assembly  510  relative to reload  400 ). 
     The actuation of fire switch  178   a  or  178   b  of power handle  101 , corresponding to an actuation of right-side or left-side control button  36   a ,  36   b , causes controller circuit board  142  to provide appropriate signals to motors  154  and  156  to activate, as appropriate, to fire staples of reload  400 , and then to advance (e.g., fire) and retract an annular knife  444  of reload  400 . 
     The actuation of switches  174   a ,  174   b  (by right-hand thumb of user) or switches  176   a ,  176   b  (by left-hand thumb of user) of switch assembly  170 , corresponding to respective actuation of right-side pair of control buttons  32   a ,  32   b  or left-side pair of control button  34   a ,  34   b , causes controller circuit board  142  to provide appropriate signals to motor  152  to activate, to advance or retract trocar member  274  of adapter assembly  200 . 
     With reference to  FIGS. 12 and 14 , power-pack core assembly  106  of handle assembly  100  includes a USB connector  180  supported on main controller circuit board  142   b  of controller circuit board  142 . USB connector  180  is accessible through control plate  160  of power-pack core assembly  106 . When power handle  101  is disposed within outer shell housing  10 , USB connector  180  is covered by plate  62  of sterile barrier plate assembly  60  of shell housing  10 . 
     As illustrated in  FIG. 1  and  FIGS. 20-65 , handle assembly  100  is configured for selective connection with adapter assembly  200 , and, in turn, adapter assembly  200  is configured for selective connection with reload  400 . 
     Adapter assembly  200  is configured to convert a rotation of coupling shaft(s)  64   a ,  64   b ,  64   c  of handle assembly  100  into axial translation useful for advancing/retracting trocar member  274  of adapter assembly  200 , for opening/closing handle assembly  100  (when anvil assembly  510  is connected to trocar member  274 ), for firing staples of reload  400 , and for firing annular knife  444  of reload  400 , as illustrated in  FIG. 22 , and as will be described in greater detail below. 
     Adapter assembly  200  includes a first drive transmitting/converting assembly for interconnecting first coupling shaft  64   a  of handle assembly  100  and an anvil assembly  510 , wherein the first drive transmitting/converting assembly converts and transmits a rotation of first coupling shaft  64   a  of handle assembly  100  to an axial translation of trocar member  274  of trocar assembly  270 , and in turn, the anvil assembly  510 , which is connected to trocar member  274 , to open/close handle assembly  100 . 
     Adapter assembly  200  includes a second drive transmitting/converting assembly for interconnecting third coupling shaft  64   c  of handle assembly  100  and a second axially translatable drive member of reload  400 , wherein the second drive transmitting/converting assembly converts and transmits a rotation of third coupling shaft  64   c  of handle assembly  100  to an axial translation of an outer flexible band assembly  255  of adapter assembly  200 , and in turn, a driver adapter  432  of a staple driver assembly  430  of reload  400  to fire staples from a staple cartridge  420  of reload  400  and against anvil assembly  510 . 
     Adapter assembly  200  includes a third drive transmitting/converting assembly for interconnecting second coupling shaft  64   b  of handle assembly  100  and a third axially translatable drive member of reload  400 , wherein the third drive transmitting/converting assembly converts and transmits a rotation of second coupling shaft  64   b  of handle assembly  100  to an axial translation of an inner flexible band assembly  265  of adapter assembly  200 , and in turn, a knife assembly  440  of reload  400  to fire annular knife  444  against anvil assembly  510 . 
     Turning now to  FIGS. 20-24 , 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 house the components of adapter assembly  200 . Knob housing  202  includes a drive coupling assembly  210  which is configured and adapted to connect to connecting portion  108  of handle housing  102  of handle assembly  100 . 
     Adapter assembly  200  is configured to convert a rotation of either of first, second or third coupling shafts  64   a ,  64   b ,  64   c , respectively, of handle assembly  100 , into axial translations useful for operating trocar assembly  270  of adapter assembly  200 , anvil assembly  510 , and/or staple driver assembly  430  or knife assembly  440  of reload  400 , as will be described in greater detail below. 
     As illustrated in  FIGS. 57-61 , adapter assembly  200  includes a proximal inner housing member  204  disposed within knob housing  202 . Inner housing member  204  rotatably supports a first rotatable proximal drive shaft  212 , a second rotatable proximal drive shaft  214 , and a third rotatable proximal drive shaft  216  therein. Each proximal drive shaft  212 ,  214 ,  216  functions as a rotation receiving member to receive rotational forces from respective coupling shafts  64   a ,  64   c  and  64   b  of handle assembly  100 , as described in greater detail below. 
     As described briefly above, drive coupling assembly  210  of adapter assembly  200  is also configured to rotatably support first, second and third connector sleeves  218 ,  222  and  220 , respectively, arranged in a common plane or line with one another. Each of connector sleeves  218 ,  220 ,  222  is configured to mate with respective first, second and third coupling shafts  64   a ,  64   c  and  64   b  of handle assembly  100 , as described above. Each of connector sleeves  218 ,  220 ,  222  is further configured to mate with a proximal end of respective first, second and third proximal drive shafts  212 ,  214 ,  216  of adapter assembly  200 . 
     Drive coupling assembly  210  of adapter assembly  200  also includes, as illustrated in  FIGS. 26, 34, 35 and 40 , a first, a second and a third biasing member  224 ,  226  and  228  disposed distally of respective first, second and third connector sleeves  218 ,  222 ,  220 . Each of biasing members  224 ,  226  and  228  is disposed about respective first, second and third rotatable proximal drive shaft  212 ,  216  and  214 . Biasing members  224 ,  226  and  228  act on respective connector sleeves  218 ,  222  and  220  to help maintain connector sleeves  218 ,  222  and  220  engaged with the distal end of respective coupling shafts  64   a ,  64   b  and  64   c  of handle assembly  100  when adapter assembly  200  is connected to handle assembly  100 . 
     In particular, first, second and third biasing members  224 ,  226  and  228  function to bias respective connector sleeves  218 ,  222  and  220  in a proximal direction. In this manner, during connection of handle assembly  100  to adapter assembly  200 , if first, second and or third connector sleeves  218 ,  222  and/or  220  is/are misaligned with coupling shafts  64   a ,  64   b  and  64   c  of handle assembly  100 , first, second and/or third biasing member(s)  224 ,  226  and/or  228  are compressed. Thus, when handle assembly  100  is operated, coupling shafts  64   a ,  64   c  and  64   b  of handle assembly  100  will rotate and first, second and/or third biasing member(s)  224 ,  228  and/or  226  will cause respective first, second and/or third connector sleeve(s)  218 ,  220  and/or  222  to slide back proximally, effectively connecting coupling shafts  64   a ,  64   c  and  64   b  of handle assembly  100  to first, second and/or third proximal drive shaft(s)  212 ,  214  and  216  of drive coupling assembly  210 . 
     As briefly mentioned above, adapter assembly  200  includes a first, a second and a third force/rotation transmitting/converting assembly  240 ,  250 ,  260 , respectively, disposed within inner housing member  204  and outer tube  206 . Each force/rotation transmitting/converting assembly  240 ,  250 ,  260  is configured and adapted to transmit or convert a rotation of a first, second and third coupling shafts  64   a ,  64   c  and  64   b  of handle assembly  100  into axial translations to effectuate operation of trocar assembly  270  of adapter assembly  200 , and of staple driver assembly  430  or knife assembly  440  of reload  400 . 
     As shown in  FIGS. 25-28 , first force/rotation transmitting/converting assembly  240  includes first rotatable proximal drive shaft  212 , as described above, a second rotatable proximal drive shaft  281 , a rotatable distal drive shaft  282 , and a coupling member  286 , each of which are supported within inner housing member  204 , drive coupling assembly  210  and/or an outer tube  206  of adapter assembly  200 . First force/rotation transmitting/converting assembly  240  functions to extend/retract trocar member  274  of trocar assembly  270  of adapter assembly  200 , and to open/close handle assembly  100  (when anvil assembly  510  is connected to trocar member  274 ). 
     First rotatable proximal drive shaft  212  includes a non-circular or shaped proximal end portion configured for connection with first connector  218  which is connected to respective first coupling shaft  64   a  of handle assembly  100 . First rotatable proximal drive shaft  212  includes a non-circular recess formed therein which is configured to key with a respective complimentarily shaped proximal end portion  281   a  of second rotatable proximal drive shaft  281 . Second rotatable proximal drive shaft  281  includes a distal end portion  281   b  defining an oversized recess therein which is configured to receive a proximal end portion  282   a  of first rotatable distal drive shaft  282 . Proximal end portion  282   a  of first rotatable distal drive shaft  282  is pivotally secured within the recess in distal end  28  lb of second rotatable proximal drive shaft  281  by a pin  283   a  received through the oversized recess in distal end portion  28  lb of second rotatable proximal drive shaft  281 . 
     First rotatable distal drive shaft  282  includes a proximal end portion  282   a , and a distal end portion  282   b  which is pivotally secured within a recess of coupling member  286 . Distal end portion  282   b  of first rotatable distal drive shaft  282  is pivotally secured within a recess in a proximal end of coupling member  286  by a pin  283   b  received through the recess in the proximal end portion of coupling member  286 . Proximal and distal end portions  282   a ,  282   b  of first rotatable distal drive shaft  282  define oversized openings for receiving pins  283   a ,  283   b , respectively. 
     Coupling member  286  includes a proximal end  286   a  defining a recess  286 c for receiving distal end portion  282   b  of first rotatable distal drive shaft  282 , a distal end  286   b  defining a recess  286 d for operably receiving a non-circular stem  276 c on proximal end  276   a  of a drive screw  276  of trocar assembly  270 . 
     First force/rotation transmitting/converting assembly  240  further includes a trocar assembly  270  removably supported in a distal end of outer tube  206 . Trocar assembly  270  includes an outer housing  272 , a trocar member  274  slidably disposed within tubular outer housing  272 , and a drive screw  276  operably received within trocar member  274  for axially moving trocar member  274  relative to tubular housing  272 . In particular, trocar member  274  includes a proximal end  274   a  having an inner threaded portion which engages a threaded distal portion  276   b  of drive screw  276 . Trocar member  274  further includes at least one longitudinally extending flat formed in an outer surface thereof which mates with a corresponding flat formed in tubular housing  272  thereby inhibiting rotation of trocar member  274  relative to tubular housing  272  as drive screw  276  is rotated. A distal end  274   b  of trocar member  274  is configured to selectively engage anvil assembly  510  ( FIGS. 73-75 ). 
     Tubular housing  272  of trocar assembly  270  is axially and rotationally fixed within outer tube  206  of adapter assembly  200 . Tubular housing  272  defines a pair of radially opposed, and radially oriented openings  272   a  which are configured and dimensioned to cooperate with a pair of lock pins  275   c  of a trocar assembly release mechanism  275 . With reference to  FIGS. 29-33 , adapter assembly  200  includes a support block  292  fixedly disposed within outer tube  206 . Support block  292  is disposed proximal of a connector sleeve  290  and proximal of a strain sensor  320   a  of a strain gauge assembly  320 , as described in greater detail below. The pair of lock pins  275   c  extend through support block  292  and into tubular housing  272  of trocar assembly  270  to connect trocar assembly  270  to adapter assembly  200 . 
     As illustrated in  FIGS. 29-33 , trocar assembly release mechanism  275  includes a release button  275   a  pivotally supported on support block  292  and in outer tube  206 . Release button  275   a  is spring biased to a locked/extended condition. Trocar assembly release mechanism  275  further includes a spring clip  275   b  connected to release button  275   a , wherein spring clip  275   b  includes a pair of legs that extend through support block  292  and transversely across trocar assembly  270 . Each of the pair of legs of spring clip  275   b  extends through a respective lock pin  275   c  which is slidably disposed within a respective radial opening  272   a  of tubular housing  272  and radial opening  292   a  of support block  292  (see  FIG. 31 ). 
     In use, when release button  275   a  is depressed (e.g., in a radially inward direction,  FIG. 33 ), release button  275   a  moves spring clip  275   b  transversely relative to trocar assembly  270 . As spring clip  275   b  is moved transversely relative to trocar assembly  270 , the pair of legs of spring clip  275   b  translate through the pair of lock pins  275   c  such that a goose-neck in each leg acts to cam and urge the pair of lock pins  275   c  radially outward. Each of the pair of lock pins  275   c  is urged radially outward by a distance sufficient that each of the pair of lock pins  275   c  clears respective opening  272   a  of tubular housing  272 . With the pair of lock pins  275   c  free and clear of tubular housing  272 , trocar assembly  270  may be axially withdrawn from within the distal end of outer tube  206  of adapter assembly  200 . 
     In operation, as first rotatable proximal drive shaft  212  is rotated, due to a rotation of first connector sleeve  218 , as a result of the rotation of first coupling shaft  64   a  of handle assembly  100 , second rotatable distal drive shaft  281  is caused to be rotated. Rotation of second rotatable distal drive shaft  281  results in contemporaneous rotation of first rotatable distal drive shaft  282 . Rotation of first rotatable distal drive shaft  282  causes contemporaneous rotation of coupling member  286 , which, in turn, causes contemporaneous rotation of drive screw  276  of trocar assembly  270 . As drive screw  276  is rotated within and relative to trocar member  274 , engagement of the inner threaded portion of trocar member  274  with threaded distal portion  276   b  of drive screw  276  causes axial translation of trocar member  274  within tubular housing  272  of trocar assembly  270 . Specifically, rotation of drive screw  276  in a first direction causes axial translation of trocar member  274  in a first direction (e.g., extension of trocar assembly  270  of handle assembly  100 ), and rotation of drive screw  276  in a second direction causes axial translation of trocar member  274  in a second direction (e.g., retraction of trocar assembly  270  of handle assembly  100 ). 
     When anvil assembly  510  is connected to trocar member  274 , as will be described in detail below, the axial translation of trocar member  274  in the first direction results in an opening of reload  400 , and the axial translation of trocar member  274  in the second direction results in a closing of reload  400 . 
     Forces during an actuation or trocar member  274  or a closing of reload  400  may be measured by strain sensor  320   a  of strain gauge assembly  320  in order to:
         determine a presence and proper engagement of trocar assembly  270  in adapter assembly  200 ;   determine a presence of anvil assembly  510  during calibration;   determine misalignment of the splines of trocar member  274  with longitudinally extending ridges  416  of reload  400 ;   determine a re-clamping of a previously tiled anvil assembly  510 ;   determine a presence of obstructions during clamping or closing of reload  400 ;   determine a presence and connection of anvil assembly  510  with trocar member  274 ;   monitor and control a compression of tissue disposed within reload  400 ;   monitor a relaxation of tissue, over time, clamped within reload  400 ;   monitor and control a firing of staples from reload  400 ;   detect a presence of staples in reload  400 ;   monitors forces during a firing and formation of the staples as the staples are being ejected from reload  400 ;   optimize formation of the staples (e.g., staple crimp height) as the staples are being ejected from reload  400  for different indications of tissue;   monitor and control a firing of annular knife  444  of reload  400 ;   monitor and control a completion of the firing and cutting procedure; and   monitor a maximum firing force and control the firing and cutting procedure to protect against exceeding a predetermined maximum firing force.       

     In operation, strain sensor  320   a  of strain gauge assembly  320  of adapter assembly  200  measures and monitors the retraction of trocar member  274 , as described above. During the closing of reload  400 , if and when head assembly  512  of anvil assembly  510  contacts tissue, an obstruction, staple cartridge  420  or the like, a reaction force is exerted on head assembly  512  which is in a generally distal direction. This distally directed reaction force is communicated from head assembly  512  to center rod assembly  514  of anvil assembly  510 , which in turn is communicated to trocar assembly  270 . Trocar assembly  270  then communicates the distally directed reaction force to the pair of pins  275   c  of trocar assembly release mechanism  275 , which in turn then communicate the reaction force to support block  292 . Support block  292  then communicates the distally directed reaction force to strain sensor  320   a  of strain gauge assembly  320 . 
     Strain sensor  320   a  of strain gauge assembly  320  is a device configured to measure strain (a dimensionless quantity) on an object that it is adhered to (e.g., support block  292 ), such that, as the object deforms, a metallic foil of the strain sensor  320   a  is also deformed, causing an electrical resistance thereof to change, which change in resistance is then used to calculate loads experienced by trocar assembly  270 . 
     Strain sensor  320   a  of strain gauge assembly  320  then communicates signals to main controller circuit board  142   b  of power-pack core assembly  106  of handle assembly  100 . Graphics are then displayed on display screen  146  of power-pack core assembly  106  of handle assembly  100  to provide the user with real-time information related to the status of the firing of handle assembly  100 . 
     With reference to  FIGS. 34-38 , second force/rotation transmitting/converting assembly  250  of adapter assembly  200  includes second proximal drive shaft  214 , as described above, a first coupling shaft  251 , a planetary gear set  252 , a staple lead screw  253 , and a staple driver  254 , each of which are supported within inner housing member  204 , drive coupling assembly  210  and/or an outer tube  206  of adapter assembly  200 . Second force/rotation transmitting/converting assembly  250  functions to fire staples of reload  400  for formation against anvil assembly  510 . 
     Second rotatable proximal drive shaft  214  includes a non-circular or shaped proximal end portion configured for connection with second connector or coupler  220  which is connected to respective second coupling shaft  64   c  of handle assembly  100 . Second rotatable proximal drive shaft  214  further includes a distal end portion  214   b  having a spur gear non-rotatably connected thereto. 
     First coupling shaft  251  of second force/rotation transmitting/converting assembly  250  includes a proximal end portion  251   a  having a spur gear non-rotatably connected thereto, and a distal end portion  25  lb having a spur gear non-rotatably connected thereto. The spur gear at the proximal end portion  251   a  of first coupling shaft  251  is in meshing engagement with the spur gear at the distal end portion  214   b  of the second rotatable proximal drive shaft  214 . 
     Planetary gear set  252  of second force/rotation transmitting/converting assembly  250  includes a first cannulated sun gear  252   a , a first set of planet gears  252   b , a ring gear  252   c , a second set of planet gears  252   d , and a second cannulated sun gear  252   e . First sun gear  252   a  is in meshing engagement with the spur gear at the distal end portion  25  lb of first coupling shaft  251 . The first set of planet gears  252   b  are interposed between, and are in meshing engagement with, first sun gear  252   a  and ring gear  252   c . The second set of planet gears  252   d  are interposed between, and are in meshing engagement with, second sun gear  252   e  and ring gear  252   c . Ring gear  252   c  is non-rotatably supported in outer tube  206  of adapter assembly  200 . 
     Planetary gear set  252  of second force/rotation transmitting/converting assembly  250  includes a washer  252   f  disposed within ring gear  252   c , and between the first set of planet gears  252   b  and the second set of planet gears  252   d . The first set of planet gears  252   b  are rotatably supported radially about washer  252   f , and second sun gear  252   e  is non-rotatably connected to a center of washer  252   f.    
     Staple lead screw  253  of second force/rotation transmitting/converting assembly  250  includes a proximal flange  253   a  and a distal threaded portion  253   b  extending from flange  253   a . Staple lead screw  253  defines a lumen  253   c  therethrough. The second set of planet gears  252   d  are rotatably supported radially about proximal flange  253   a  of staple lead screw  253 . 
     Staple driver  254  of second force/rotation transmitting/converting assembly  250  includes a central threaded lumen  254   a  extending therethrough and is configured and dimensioned to support distal threaded portion  253   b  of staple lead screw  253  therein. Staple driver  254  includes a pair of tabs  254   b  projecting radially from an outer surface thereof, and which are configured for connection to outer flexible band assembly  255  of adapter assembly  200 , as will be described in greater detail below. 
     With reference now to  FIGS. 34, 35 and 43-51 , second force/rotation transmitting/converting assembly  250  of adapter assembly  200  includes an outer flexible band assembly  255  secured to staple driver  254 . Outer flexible band assembly  255  includes first and second flexible bands  255   a ,  255   b  laterally spaced and connected at proximal ends thereof to a support ring  255   c  and at distal ends thereof to a proximal end of a support base  255   d . Each of first and second flexible bands  255   a ,  255   b  is attached to support ring  255   c  and support base  255   d.    
     Outer flexible band assembly  255  further includes first and second connection extensions  255   e ,  255   f  extending proximally from support ring  255   c . First and second connection extensions  255   e ,  255   f  are configured to operably connect outer flexible band assembly  255  to staple driver  254  of second force/rotation transmitting/converting assembly  250 . In particular, each of first and second connection extensions  255   e ,  255   f  defines an opening configured to receive a respective tab  254   b  of staple driver  254 . Receipt of tabs  254   b  of staple driver  254  within the openings of respective first and second connection extensions  255   e ,  255   f  secures outer flexible band assembly  255  to staple driver  254  of second force/rotation transmitting/converting assembly  250 . 
     Support base  255   d  extends distally from flexible bands  255   a ,  255   b  and is configured to selectively contact driver adapter  432  of staple driver assembly  430  of reload  400 . 
     Flexible bands  255   a ,  255   b  are fabricated from stainless steel  301  half hard and are configured to transmit axial pushing forces along a curved path. 
     Second force/rotation transmitting/converting assembly  250  and outer flexible band assembly  255  are configured to receive first rotatable proximal drive shaft  212 , first rotatable distal drive shaft  282 , and trocar assembly  270  of first force/rotation transmitting/converting assembly  240  therethrough. Specifically, first rotatable proximal drive shaft  212  is non-rotatably connected to second rotatable proximal drive shaft  281  which in turn is rotatably disposed within and through first cannulated sun gear  252   a  of first planetary gear set  252 , second cannulated sun gear  252   e  of planetary gear set  252 , staple lead screw  253 , and staple driver  254 . 
     Second force/rotation transmitting/converting assembly  250  and outer flexible band assembly  255  are also configured to receive third force/rotation transmitting/converting assembly  260  therethrough. Specifically, as described below, inner flexible band assembly  265  is slidably disposed within and through outer flexible band assembly  255 . 
     First rotatable distal drive shaft  282  of first force/rotation transmitting/converting assembly  240  is rotatably disposed within support base  255   d  of outer flexible band assembly  255 , while trocar member  274  of trocar assembly  270  of first force/rotation transmitting/converting assembly  240  is slidably disposed within support base  255   d  of outer flexible band assembly  255 . 
     Outer flexible band assembly  255  is also configured to receive inner flexible band assembly  265  therethrough. 
     In operation, as second rotatable proximal drive shaft  214  is rotated due to a rotation of second connector sleeve  220 , as a result of the rotation of the second coupling shaft  64   c  of handle assembly  100 , first coupling shaft  251  is caused to be rotated, which in turn causes first cannulated sun gear  252   a  to rotate. Rotation of first cannulated sun gear  252   a , results in contemporaneous rotation of the first set of planet gears  252   b , which in turn causes washer  252   f  to contemporaneously rotate second cannulated sun gear  252   e . Rotation of second cannulated sun gear  252   e , results in contemporaneous rotation of the second set of planet gears  252   d , which in turn causes contemporaneous rotation of staple lead screw  253 . As staple lead screw  253  is rotated, staple driver  254  is caused to be axially translated, which in turn causes outer flexible band assembly  255  to be axially translated. As outer flexible band assembly  255  is axially translated, support base  255   d  presses against driver adapter  432  of staple driver assembly  430  of reload  400  to distally advance driver  434  and fire staples “S” ( FIG. 67 ) of reload  400  against anvil assembly  510  for formation of staples “S” in underlying tissue. 
     With reference to  FIGS. 39-42 and 45-51 , third force/rotation transmitting/converting assembly  260  of adapter assembly  200  includes third proximal drive shaft  216 , as described above, a second coupling shaft  261 , a planetary gear set  262 , a knife lead screw  263 , and a knife driver  264 , each of which are supported within inner housing member  204 , drive coupling assembly  210  and/or an outer tube  206  of adapter assembly  200 . Third force/rotation transmitting/converting assembly  260  functions to fire knife of reload  400 . 
     Third rotatable proximal drive shaft  216  includes a non-circular or shaped proximal end portion configured for connection with third connector or coupler  222  which is connected to respective third coupling shaft  64   b  of handle assembly  100 . Third rotatable proximal drive shaft  216  further includes a distal end portion  216   b  having a spur gear non-rotatably connected thereto. 
     Second coupling shaft  261  of third force/rotation transmitting/converting assembly  260  includes a proximal end portion  261   a  having a spur gear non-rotatably connected thereto, and a distal end portion  261   b  having a spur gear non-rotatably connected thereto. The spur gear at the proximal end portion  261   a  of second coupling shaft  261  is in meshing engagement with the spur gear at the distal end portion  216   b  of the third rotatable proximal drive shaft  216 . 
     Planetary gear set  262  of third force/rotation transmitting/converting assembly  260  includes a first cannulated sun gear  262   a , a first set of planet gears  262   b , a ring gear  262   c , a second set of planet gears  262   d , and a second cannulated sun gear  262   e . First sun gear  262   a  is non-rotatably supported on a distal end portion of a hollow shaft  269 . Hollow shaft  269  includes a spur gear  269   a  non-rotatably supported on a proximal end thereof. Spur gear  269   a  of hollow shaft  269  is in meshing engagement with the spur gear at the distal end portion  261   b  of second coupling shaft  261 . The first set of planet gears  262   b  are interposed between, and are in meshing engagement with, first sun gear  262   a  and ring gear  262   c . The second set of planet gears  262   d  are interposed between, and are in meshing engagement with, second sun gear  262   e  and ring gear  262   c . Ring gear  262   c  is non-rotatably supported in outer tube  206  of adapter assembly  200 . 
     Planetary gear set  262  of third force/rotation transmitting/converting assembly  260  includes a washer  262   f  disposed within ring gear  262   c , and between the first set of planet gears  262   b  and the second set of planet gears  262   d . The first set of planet gears  262   b  are rotatably supported radially about washer  262   f , and second sun gear  262   e  is non-rotatably connected to a center of washer  262   f.    
     Knife lead screw  263  of second force/rotation transmitting/converting assembly  260  includes a proximal flange  263   a  and a distal threaded portion  263   b  extending from flange  263   a . Knife lead screw  263  defines a lumen  263   c  therethrough. The second set of planet gears  262   d  are rotatably supported radially about proximal flange  263   a  of knife lead screw  263 . 
     Knife driver  264  of second force/rotation transmitting/converting assembly  260  includes a central threaded lumen  264   a  extending therethrough and is configured and dimensioned to support distal threaded portion  263   b  of knife lead screw  263  therein. Knife driver  264  includes a pair of tabs  264   b  projecting radially from an outer surface thereof, and which are configured for connection to inner flexible band assembly  265  of adapter assembly  200 , as will be described in greater detail below. 
     With reference now to  FIGS. 39-42 , third force/rotation transmitting/converting assembly  260  of adapter assembly  200  includes an inner flexible band assembly  265  secured to knife driver  264 . Inner flexible band assembly  265  includes first and second flexible bands  265   a ,  265   b  laterally spaced and connected at proximal ends thereof to a support ring  265   c  and at distal ends thereof to a proximal end of a support base  265   d . Each of first and second flexible bands  265   a ,  265   b  are attached to support ring  265   c  and support base  265   d . Inner flexible band assembly  265  is configured to receive first rotatable proximal drive shaft  212 , first rotatable distal drive shaft  282 , and trocar assembly  270  of first force/rotation transmitting/converting assembly  240  therethrough. 
     Inner flexible band assembly  265  further includes first and second connection extensions  265   e ,  265   f  extending proximally from support ring  265   c . First and second connection extensions  265   e ,  265   f  are configured to operably connect inner flexible band assembly  265  to knife driver  264  of third force/rotation transmitting/converting assembly  260 . In particular, each of first and second connection extensions  265   e ,  265   f  defines an opening configured to receive a respective tab  264   b  of knife driver  264 . Receipt of tabs  264   b  of knife driver  264  within the openings of respective first and second connection extensions  265   e ,  265   f  secures inner flexible band assembly  265  to knife driver  264  of third force/rotation transmitting/converting assembly  260 . 
     Support base  265   d  extends distally from flexible bands  265   a ,  265   b  and is configured to connect with knife carrier  442  of knife assembly  440  of reload  400 . 
     Flexible bands  265   a ,  265   b  are fabricated from stainless steel  301  half hard and are configured to transmit axial pushing forces along a curved path. 
     Third force/rotation transmitting/converting assembly  260  and inner flexible band assembly  265  are configured to receive first rotatable proximal drive shaft  212 , first rotatable distal drive shaft  282 , and trocar assembly  270  of first force/rotation transmitting/converting assembly  240  therethrough. Specifically, first rotatable proximal drive shaft  212  is rotatably disposed within and through hollow shaft  269 , first cannulated sun gear  262   a  of first planetary gear set  262 , second cannulated sun gear  262   e  of planetary gear set  262 , knife lead screw  263 , and knife driver  264 . 
     First rotatable distal drive shaft  282  of first force/rotation transmitting/converting assembly  240  is also rotatably disposed within support base  265   d  of inner flexible band assembly  265 , while trocar member  274  of trocar assembly  270  of first force/rotation transmitting/converting assembly  240  is slidably disposed within support base  265   d  of inner flexible band assembly  265 . 
     In operation, as third rotatable proximal drive shaft  216  is rotated due to a rotation of third connector sleeve  222 , as a result of the rotation of the third coupling shaft  64   b  of handle assembly  100 , second coupling shaft  261  is caused to be rotated, which in turn causes hollow shaft  269  to rotate. Rotation of hollow shaft  269  results in contemporaneous rotation of the first set of planet gears  262   b , which in turn causes washer  262   f  to rotate second cannulated sun gear  262   e . Rotation of second cannulated sun gear  262   e  causes contemporaneous rotation of the second set of planet gears  262   d , which in turn causes knife lead screw  263  to rotate. As knife lead screw  263  is rotated, knife driver  264  is caused to be axially translated, which in turn causes inner flexible band assembly  265  to be axially translated. As inner flexible band assembly  265  is axially translated, support base  265   d  presses against knife carrier  442  of reload  400  to distally advance knife carrier  442  and fire annular knife  444  of reload  400  against anvil assembly  510  for cutting of tissue clamped in reload  400 . 
     Turning now to  FIGS. 21-24 , adapter assembly  200  includes an outer tube  206  extending from knob housing  202 . As mentioned above, outer tube  206  is configured to support first, second and third force/rotation transmitting/converting assembly  240 ,  250 ,  260 , respectively. Adapter assembly  200  further includes a frame assembly  230  supported in outer tube  206 . Frame assembly  230  is configured to support and guide flexible bands  255   a ,  255   b  of outer flexible band assembly  255 , and flexible bands  265   a ,  265   b  of inner flexible band assembly  265 , as flexible bands  255   a ,  255   b ,  265   a ,  265   b  are axially translated through outer tube  206 . 
     Frame assembly  230  includes first and second proximal spacer members  232   a ,  232   b , and first and second distal spacer members  234   a ,  234   b . When secured together, first and second proximal spacer members  232   a ,  232   b  define a pair of inner longitudinal slots  234   c  for slidably receiving first and second flexible bands  265   a ,  265   b  of inner flexible band assembly  265  and a pair of outer longitudinal slots  234   d  for slidably receiving first and second flexible bands  255   a ,  255   b  of outer flexible band assembly  255 . First and second proximal spacer members  232   a ,  232   b  further define a longitudinal passage therethrough for receipt of first force/rotation transmitting/converting assembly  240  and trocar assembly  270 . 
     First and second distal spacer members  234   a ,  234   b  define a pair of inner slots  234   c  for slidably receiving first and second flexible bands  265   a ,  265   b  of inner flexible band assembly  265  and a pair of outer slots  234   d  for slidably receiving first and second flexible bands  255   a ,  255   b  of outer flexible band assembly  255 . First and second distal spacer members  234   a ,  234   b  further define a longitudinal passage therethrough for receipt of first force/rotation transmitting/converting assembly  240 .and trocar assembly  270 . 
     First and second proximal spacer members  232   a ,  232   b  and first and second distal spacer members  234   a ,  234   b  are formed of plastic to reduce friction with flexible bands  255   a ,  255   b  of outer flexible band assembly  255 , and flexible bands  265   a ,  265   b  of inner flexible band assembly  265 . 
     With reference now to  FIGS. 44-50 , frame assembly  230  further includes a seal member  235 . Seal member  235  engages outer tube  206 , inner and outer flexible bands  255   a ,  255   b  and  265   a ,  265   b  of respective inner and outer flexible band assemblies  255 ,  265  and trocar assembly  270 , and wiring extending therethrough, in a sealing manner. In this manner, seal member  235  operates to provide a fluid tight seal through between the distal end and the proximal end of outer tube  206 . 
     Adapter assembly  200  further includes a connector sleeve  290  fixedly supported at a distal end of outer tube  206 . Connector sleeve  290  is configured to selectively secure securing reload  400  to adapter assembly  200 , as will be described in greater detail below. Connector sleeve  290  is also configured to be disposed about distal ends of outer and inner flexible assemblies  255 ,  265  and trocar assembly  270 . In particular, a proximal end of connector sleeve  290  is received within and securely attached to the distal end of outer tube  206  and is configured to engage a stain gauge assembly  320  of adapter assembly  200 , and a distal end of connector sleeve  290  is configured to selectively engage a proximal end of reload  400 . 
     With reference now to  FIGS. 52-55, 60 and 69 , adapter assembly  200  includes an electrical assembly  310  disposed therewithin, and configured for electrical connection with and between handle assembly  100  and reload  400 . Electrical assembly  310  serves to allow for calibration and communication information (e.g., identifying information, life-cycle information, system information, force information) to the main controller circuit board  142   b  of power-pack core assembly  106  via electrical receptacle  149  of power-pack core assembly  106  of handle assembly  100 . 
     Electrical assembly  310  includes a proximal pin connector assembly  312 , a proximal harness assembly  314  in the form of a ribbon cable, a distal harness assembly  316  in the form of a ribbon cable, a strain gauge assembly  320 , and a distal electrical connector  322 . 
     Proximal pin connector assembly  312  of electrical assembly  310  is supported within inner housing member  204  and drive coupling assembly  210  of knob housing  202 . Proximal pin connector assembly  312  includes a plurality of electrical contact blades  312   a  supported on a circuit board  312   b  and which enable electrical connection to pass-through connector  66  of plate assembly  60  of outer shell housing  10  of handle assembly  100 . Proximal harness assembly  314  is electrically connected to circuit board  312   b  of proximal pin connector assembly  312  ( FIGS. 53 and 54 ). 
     Strain gauge assembly  320  is electrically connected to proximal pin connector assembly  312  via proximal and distal harness assemblies  314 ,  316 . Strain gauge assembly  320  includes a strain sensor  320   a  supported in outer tube  206  of adapter assembly  200 . Strain sensor  320   a  is electrically connected to distal harness assembly  316  via a sensor flex cable  320   b . Strain sensor  320   a  defines a lumen therethrough, through which trocar assembly  270  extends. 
     As illustrated in  FIGS. 29-33 , trocar assembly  270  of first force/rotation transmitting/converting assembly  240  extends through strain sensor  320   a  of strain gauge assembly  320 . Strain gauge assembly  320  provides a closed-loop feedback to a firing/clamping load exhibited by first, second and third force/rotation transmitting/converting assembly  240 ,  250 ,  260 , respectively. 
     Strain sensor  320   a  of strain gauge assembly  320  is supported in outer tube  206  and interposed between connector sleeve  290  and support block  292 . Support block  292  includes a raised ledge  292   b  (see  FIG. 29 ) which extends distally therefrom and which is in contact with strain sensor  320   a.    
     With reference now to  FIGS. 53-55 , electrical assembly  310  includes, as mentioned above, a distal electrical connector  322  which is supported in connector sleeve  290 . Distal electrical connector  322  is configured to selectively mechanically and electrically connect to chip assembly  460  of reload  400  when reload  400  is connected to adapter assembly  200 . 
     Distal electrical connector  322  includes a plug member  322   a , first and second wires  323   a ,  323   b , and first and second contact members  324   a ,  324   b  electrically connected to respective first and second wires  323   a ,  323   b . Plug member  322   a  includes a pair of arms  322   b ,  322   c  supporting first and second contact members  324   a ,  324   b , respectively. The pair of arms  322   b ,  322   c  are sized and dimensioned to be received within a cavity  461   a  of chip assembly  460  and about a circuit board assembly  464  of reload  400  when reload  400  is connected to adapter assembly  200 . 
     First and second contact members  324   a ,  324   b  of distal electrical connector  322  are configured to engage respective contact members  464   b  of circuit board assembly  464  of chip assembly  460  of reload  400  when reload  400  is connected to adapter assembly  200 . 
     With reference now to  FIGS. 57-65 , adapter assembly  200  includes a rotation assembly  330  configured to enable rotation of adapter assembly  200  relative to handle assembly  100 . Specifically, outer knob housing  202  and an outer tube  206  of adapter assembly  200  are rotatable relative to drive coupling assembly  210  of adapter assembly  200 . 
     Rotation assembly  330  includes a lock button  332  operably supported on outer knob housing  202 . As will be described in further detail below, when rotation assembly  330  is in an unlocked configuration, outer knob housing  202  and an outer tube  206  are rotatable along a longitudinal axis of adapter assembly  200  relative to drive coupling assembly  210 . When rotation assembly  330  is in a locked configuration, outer knob housing  202  and an outer tube  206  are rotationally secured relative to drive coupling assembly  210 . In particular, being that outer tube  206  has a curved profile, rotation of outer knob housing  202  and an outer tube  206  about the longitudinal axis of adapter assembly  200  causes handle assembly  100  to be positioned in various orientations relative to adapter assembly  200  in order to provide the clinician with increased flexibility in manipulating the surgical instrument in the target surgical site. 
     Lock button  332  of rotation assembly  330  is configured to operatively engage inner housing member  204  of adapter assembly  200 . Inner housing member  204  is a substantially cylindrical member defining a pair of longitudinal openings for receiving at least portions of first and second force/rotation transmitting/converting assemblies  240 ,  250  therethrough. Inner housing member  204  includes proximal and distal annular flanges  204   a ,  204   b  and further defines proximal and distal outer annular grooves. The proximal annular groove of inner housing member  204  accommodates an inner annular flange of outer knob housing  202  to rotatably secure outer knob housing  202  to inner housing member  204 . 
     With reference still to  FIGS. 57-65 , distal annular flange  204   b  and the distal annular groove of inner housing member  204  operate in combination with rotation assembly  330  of adapter assembly  200  to secure outer knob housing  202  in fixed rotational orientations relative to inner housing member  204 . In particular, distal annular flange  204   b  of inner housing member  204  defines first, second, and third radial cutouts  204   c ,  204   d ,  204   e  configured to selectively receive a lock shoe  334  of lock button  332  of rotation assembly  330 . The first and third cutouts  204   c ,  204   e  are opposed to one another, and second cutout  204   d  is oriented perpendicular to the first and third cutouts  204   c ,  204   e.    
     With reference to  FIGS. 60-61 , outer knob housing  202  has a frustoconical profile including a plurality of ridges configured for operable engagement by a clinician. Outer knob housing  202  defines a radial opening for operably supporting lock button  332 . The opening in outer knob housing  202  is positioned in alignment or registration with the distal annular groove of inner housing member  204  such that lock button  332  of rotation assembly  330  is receivable with the distal annular groove and selectively receivable within each of the first, second, and third cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  of inner housing member  204 . 
     As mentioned above, rotation assembly  330  of adapter assembly  200  includes a lock button  332  operably supported in an opening of outer knob housing  202  and configured for actuating rotation assembly  330 . Rotation assembly  330  further includes a lock shoe  334  disposed between outer knob housing  202  and inner housing member  204  and axially slidable relative to lock button  332  and inner housing member  204 . A biasing member  336  is interposed between lock button  332  and lock shoe  334  to urge lock button  332  to a locked position, wherein lock shoe  334  is disposed within one of first, second, and third cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  of inner housing member  204 . 
     Lock button  332  is configured for operable engagement by a clinician. Lock button member  332  defines an angled cam slot  332   a  formed therein for receiving a cam pin or boss  334   a  of lock shoe  334 . The biasing member  336  biases lock button  332  and lock shoe  334  away from one another, and urges lock shoe  334  into contact with distal annular flange  204   b  of inner housing member  204  and into one of first, second, and third cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  when lock shoe  334  is in registration with one of first, second, and third cutouts  204   c ,  204   d ,  204   e.    
     As mentioned above, lock shoe  334  is configured to be selectively received within one of the first, second, and third radial cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  of inner housing member  204 . Specifically, lock shoe  334  includes or defines a shoulder  334   a  projecting from a surface thereof for receipt in one of the first, second, and third radial cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  when shoulder  334   a  of lock shoe  334  is in registration with one of the first, second, and third radial cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  and lock button  332  is un-depressed. When shoulder  334   a  of lock shoe  334  is free of any of the first, second, and third radial cutouts  204   c ,  204   d ,  204   e  in distal annular flange  204   b  (e.g., rotation assembly  330  is in an unlocked condition), outer knob housing  202  is free to rotate relative to inner housing member  204 , and thus adapter assembly  200  is free to rotate relative to handle assembly  100 . 
     The operation of rotation assembly  330  will now be described with continued reference to  FIGS. 57-65 . Referring initially to  FIGS. 58, 59, 61 and 64 , rotation assembly  330  is shown in a locked condition. In particular, in the locked condition, shoulder  334   a  of lock shoe  334  is received within first cutout  204   c  in distal annular flange  204   a  of inner housing member  204 . Also, in the locked condition, lock button  332  of rotation mechanism  330  is biased radially outward by biasing member  336 . 
     When lock button  332  of rotation assembly  330  is depressed, as indicated by arrow “A” in  FIG. 64 , lock button  332  moves radially inward against the bias of biasing member  336 . As lock button  332  moves radially inward, lock shoe  334  slides axially in a distal direction, against the bias of biasing member  336 . The axial sliding of lock shoe  334  moves shoulder  334   a  of lock shoe  334  from within the first radial cutout  204   c  of the distal annular flange  204   b  of inner housing member  204 , thus placing rotation assembly  330  in an unlocked condition and freeing outer knob housing  202  to rotate, as indicated by arrow “B” in  FIG. 62 , relative to inner housing member  204 . 
     Turning now to  FIG. 65 , once rotation assembly  330  is in the unlocked condition, outer knob housing  202  may be rotated relative to inner housing member  204 . The release of lock button  332  allows biasing member  336  to bias lock button  332  to its initial position. Similarly, biasing member  336  biases lock shoe  334  to its initial position. When lock shoe  334  is re-aligned with one of the first, second, and third radial cutouts  204   c ,  204   d ,  204   e  of distal annular flange  204   b  of inner housing member  204 , as outer knob housing  202  is rotated relative to inner housing member  204 , shoulder  334   a  of lock shoe  334  is free to be received within the respective first, second, and third cutout  204   c ,  204   d ,  204   e  and rotationally locks outer knob housing  202  relative to inner housing member  204  and drive coupling assembly  210  of adapter assembly  200 . 
     Rotation assembly  330  may be used throughout the surgical procedure to rotate handle assembly  100  and adapter assembly  200  relative to one another. 
     During rotation of outer knob housing  202  relative to inner housing member  204  and drive coupling assembly  210  of adapter assembly  200 , since proximal drive shafts  212 ,  214 ,  216  are supported in drive coupling assembly  210 , and since first coupling shaft  251  of second force/rotation transmitting/converting assembly  250 , second coupling shaft  261  of third force/rotation transmitting/converting assembly  260 , and second rotatable proximal drive shaft  281  of first force/rotation transmitting/converting assembly  240  are supported in inner housing member  204 , the respective angular orientations of proximal drive shaft  212  relative to second rotatable proximal drive shaft  281 , proximal drive shaft  216  relative to second coupling shaft  261 , and proximal drive shaft  214  relative to first coupling shaft  251 , are changed relative to one another. 
     Adapter assembly  200  further includes, as seen in  FIGS. 57-59 , an attachment/detachment button  342  supported thereon. Specifically, button  342  is supported on drive coupling assembly  210  of adapter assembly  200  and is biased by a biasing member  344  to an un-actuated condition. Button  342  includes a lip or ledge  342   a  formed therewith that is configured to snap behind a corresponding lip or ledge  20   a  ( FIG. 18 ) defined along recess  20  of connecting portion  108  of handle housing  102  of handle assembly  100 . In use, when adapter assembly  200  is connected to handle assembly  100 , lip  342   a  of button  342  is disposed behind lip  108   b  of connecting portion  108  of handle housing  102  of handle assembly  100  to secure and retain adapter assembly  200  and handle assembly  100  with one another. In order to permit disconnection of adapter assembly  200  and handle assembly  100  from one another, button  342  is depressed or actuated, against the bias of biasing member  344 , to disengage lip  342   a  of button  342  and lip  108   b  of connecting portion  108  of handle housing  102  of handle assembly  100 . 
     As illustrated in  FIGS. 1 and 66-80 , reload  400  is configured for operable connection to adapter assembly  200  and is configured to fire and form an annular array of surgical staples, and to sever a ring of tissue. 
     Reload  400  includes a shipping cap assembly (not shown) that is selectively received on a distal end  402  of reload  400  and can function to facilitate insertion of reload  400  into a target surgical site and to maintain staples “S” ( FIG. 67 ) within a staple cartridge  420  of reload  400 . Shipping cap assembly  401  also functions to prevent premature advancement of a staple driver assembly  430  ( FIG. 66 ) of reload  400  and of a knife assembly  440  ( FIG. 66 ) of reload  400  prior to and during attachment of reload  400  to adapter assembly  200 . 
     With reference now to  FIGS. 66-72 , reload  400  includes a housing  410  having a proximal end portion  410   a  and a distal end portion  410   b , a staple cartridge  420  fixedly secured to distal end portion  410   b  of housing  410 , a staple driver assembly  430  operably received within housing  410 , a knife assembly  440  operably received within housing  410 , a bushing member  450  received within proximal end  410   a  of housing  410 , and a chip assembly  460  mounted about bushing member  450 . 
     Housing  410  of reload  400  includes an outer cylindrical portion  412  and an inner cylindrical portion  414 . A plurality of ribs (not shown) interconnects outer and inner cylindrical portions  412 ,  414 . Outer cylindrical portion  412  and inner cylindrical portion  414  of reload  400  are coaxial and define a recess  412   a  ( FIG. 67 ) therebetween configured to operably receive staple driver assembly  430  and knife assembly  440 . Inner cylindrical portion  412  of reload  400  includes a plurality of longitudinally extending ridges  416  ( FIG. 67 ) projecting from an inner surface thereof and configured for radially aligning (e.g., clocking) anvil assembly  510  with reload  400  during a stapling procedure. As will be described in further detail below, proximal ends  416   a  of longitudinal ridges  416  are configured to facilitate selective securement of shipping cap assembly  401  with reload  400 . An annular ridge  418  ( FIG. 67 ) is formed on an outer surface of inner cylindrical portion  412  and is configured to assist in maintaining knife assembly  440  in a retracted position. 
     Staple cartridge  420  of reload  400  is fixedly secured on distal end  410   b  of housing  410  and includes a plurality of staple pockets  421  formed therein which are configured to selectively retain staples “S”. 
     With continued reference to  FIGS. 66-72 , staple driver assembly  430  of reload  400  includes a driver adapter  432  and a driver  434 . A proximal end  432   a  of driver adapter  432  is configured for selective contact and abutment with support base  255   d  of outer flexible band assembly  255  of second force/rotation transmitting/converting assembly  250  of adapter assembly  200 . In operation, during distal advancement of outer flexible band assembly  255 , as described above, support base  255   d  of outer flexible band assembly  255  contacts proximal end  432   a  of driver adapter  432  to advance driver adapter  432  and driver  434  from a first or proximal position to a second or distal position. Driver  434  includes a plurality of driver members  436  aligned with staple pockets  421  of staple cartridge  420  for contact with staples “S”. Accordingly, advancement of driver  434  relative to staple cartridge  420  causes ejection of the staples “S” from staple cartridge  420 . 
     Still referring to  FIGS. 66-72 , knife assembly  440  of reload  400  includes a knife carrier  442  and a circular knife  444  secured about a distal end  442   b  of knife carrier  442 . A proximal end  442   a  of knife carrier  442  is configured for operable connection with support base  265   d  of inner flexible band assembly  265  of third force/rotation transmitting/converting assembly  260  of adapter assembly  200 . In operation, during distal advancement of inner flexible band assembly  265 , as described above, support base  265   d  of inner flexible band assembly  265  connects with proximal end  442   a  of knife carrier  442  to advance knife carrier  442  and circular knife  444  from a first or proximal position to a second or advanced position to cause the cutting of tissue disposed between staple cartridge  420  and anvil assembly  510 . 
     Distal end  452   b  of bushing member  450  is secured within a proximal end  414   a  of inner cylindrical portion  414  of housing  410  by a plurality of ridges  452   c  formed on distal end  452   b  of bushing member  450 . 
     Chip assembly  460  includes a housing  461  from which annular flange  462  extends. Annular flange  462  extends perpendicular to a longitudinal axis of housing  461 . Annular flange  462  is configured to be received about a distal end  452   b  of bushing member  450 . 
     Chip assembly  460  includes a circuit board assembly  464  secured within a cavity  461   a  of housing  461 . Circuit board assembly  464  includes a circuit board  464   a , a pair of contact members  464   b  and a chip  464   c . A first end of circuit board  464   a  supports chip  464   c , and a second end of circuit board  464   a  supports first and second contact members  464   b . Chip  464   c  is a writable/erasable memory chip. Chip  464   c  includes the following stored information: lot number, staple size, lumen size, fire count, manufacturing stroke offsets, excessive force index, shipping cap assembly presence, and demonstration modes. Chip  464   c  includes write capabilities which allow handle assembly  100  to encode to chip  464   c  that reload  400  has been used to prevent reuse of an empty, spent or fired reload. 
     Proximal end  410   a  of housing  410  is configured for selective connection to connector sleeve  290  of adapter assembly  200 . Specifically, outer cylindrical portion  412  of housing  410  terminates in a proximal cylindrical flange  412   a  having an inner diameter which is larger than a diameter of a distal end portion  290   a  of connector sleeve  290  of adapter assembly  200 . Further, proximal end  432   a  of driver adapter  432  has an outer diameter which is smaller than the diameter of distal end portion  290   a  of connector sleeve  290 . 
     Reload  400  includes a compressible release ring  413  supported on flange  412   a  of outer cylindrical portion  412  of housing  410 . Release ring  413  has a substantially ovoid profile including a relative long axis and a relative short axis. In operation, when radially inward directed forces act along the long axis of release ring  413  (as indicated by arrows “A 1 ” of  FIG. 70 ), release ring  413  flexes radially outwardly along the short axis thereof (as indicated by arrows “A 2 ” of  FIG. 70 ). 
     Release ring  413  includes a ramp feature  413   a  projecting radially inwardly and located substantially along the short axis of release ring  413 . Ramp feature  413   a  of release ring  413  extends through a window  412   b  defined in flange  412   a  of outer cylindrical portion  412  of housing  410 . Ramp feature  413   a  of release ring  413  projects sufficiently radially inwardly so as to be selectively received in a window  290   b  defined in distal end portion  290   a  of connector sleeve  290 . 
     Reload  400  includes a retaining ring  415  connected to outer cylindrical portion  412  of housing  410  and configured to help retain release ring  413  on outer cylindrical portion  412  of housing  410 . 
     For radial alignment and clocking of reload  400  with adapter assembly  200 , reload  400  includes a longitudinally extending rib  412   c  projecting radially inwardly from outer cylindrical portion  412  of housing  410  which is configured for slidable receipt in a longitudinally extending slot  290   c  defined in distal end portion  290   a  of connector sleeve  290 . 
     To connect reload  400  with adapter assembly  200 , rib  412   c  of reload  400  is radially aligned with longitudinally extending slot  290   c  of connector sleeve  290  of adapter assembly  200 . reload  400  and adapter assembly  200  are then axially approximated towards one another until distal end portion  290   a  of connector sleeve  290  is received within flange  412   a  of outer cylindrical portion  412  of housing  410  and until ramp feature  413   a  of release ring  413  is received in window  290   b  of connector sleeve  290 . reload  400  and adapter assembly  200  are thus locked together. 
     When reload  400  is connected with adapter assembly  200 , distal electrical connector  322  of adapter assembly  200  is mechanically and electrically connected to chip assembly  460  of reload  400 . 
     To disconnect reload  400  and adapter assembly  200  from one another, release ring  413  is squeezed along the long axis thereof (in the direction of arrows “A 1 ”) to thereby remove ramp feature  413   a  of release ring  413  from within window  290   b  of connector sleeve  290 , and thus allowing reload  400  and adapter assembly  200  to be axially separated from one another. 
     Referring now to  FIGS. 71-75 , an anvil assembly  510  is provided and is configured for selective connection to trocar member  274  of adapter assembly  200  and for cooperation with reload  400 . 
     Anvil assembly  510  includes a head assembly  512  and a center rod assembly  514 . Head assembly  512  includes a post  516 , a housing  518 , a cutting ring  522 , a cutting ring cover  523 , an anvil plate  524 , a spacer or washer  525 , a cam latch member  526 , and a retainer member  527 . Post  516  is centrally positioned within housing  518 . 
     With reference still to  FIGS. 73-75 , anvil plate  524  is supported in an outer annular recess  528  of housing  518  and includes a plurality of staple pockets  530  formed therein and configured to receive and form staples. 
     Cutting ring  522  includes a central opening which is positioned about post  516  within an inner annular recess of housing  518  between post  516  and outer annular recess  528 . Cutting ring  522  is formed from polyethylene. Cutting ring cover  523  is secured to an outwardly facing or proximal surface of cutting ring  522 . 
     Retainer member  527  is positioned in the inner annular recess between cutting ring  522  and a back wall of housing  518 . Retainer member  527  is annular and includes a plurality of deformable tabs which engage a rear surface of cutting ring  522 . Retainer member  527  prevents cutting ring  522  from moving or being pushed into the inner annular recess of housing  518  until a predetermined force sufficient to deform the tabs has been applied to cutting ring  522 . When the predetermined force is reached, e.g., during cutting of tissue, cutting ring  522  is urged into the inner annular recess  536  and compresses the retainer members. 
     Turning back to  FIG. 75 , anvil center rod assembly  514  includes a center rod  552 , a plunger  554  and a plunger spring  556 . A first end of center rod  552  includes a pair of arms  159  which define a cavity  159   a . A pivot member  562  is provided to pivotally secure post  516  to center rod  552  such that anvil head assembly  512  is pivotally mounted to anvil center rod assembly  514 . 
     Cam latch member  526  is pivotally mounted within a transverse slot of post  516  of housing  518  and about pivot member  562 . Cam latch member  526  has an outer cam profile which permits plunger  554  to move forward as cam latch member  526  rotates in a clockwise direction, and permits plunger  554  to be retracted as cam latch member rotates in a counter-clockwise direction. 
     Plunger  554  is slidably positioned in a bore formed in the first end of center rod  552 . Plunger  554  includes an engagement finger which is offset from the pivot axis of anvil head assembly  512  and biased into engagement with an edge of cam latch  526 . Engagement of the finger of plunger  554  with the edge of cam latch  526  presses a leading portion of the edge of cam latch  526  against an inner periphery of cutting ring  522  to urge anvil head assembly  512  to an operative or non-tilted position on center rod  552 . 
     Anvil head assembly  512  may be tilted relative to anvil center rod assembly  514  in a pre-fired tilted position. Tilting of anvil head assembly  512  relative to anvil center rod assembly  514  causes the body portion of cam latch member  526  to engage a finger  166  of plunger  554 . As cam latch member  526  rotates with the tilting of anvil head assembly  512 , plunger  554  is retracted with the bore of anvil center rod assembly  514 , thereby compressing spring  556 . In this manner, finger  566  of plunger  554  is distally biased against the body portion of cam latch member  526 . 
     With reference to  FIGS. 74-75 , a second end of center rod  552  includes a bore  580  defined by a plurality of flexible arms  582 . The proximal end of each of the flexible arms  582  includes an internal shoulder dimensioned to releasably engage a shoulder of trocar  274  of trocar assembly  270  of adapter assembly  200  to secure anvil assembly  510  to adapter assembly  200 . A plurality of splines  586  are formed about center rod  552 . Splines  586  function to align and/or clock anvil assembly  510  with staple cartridge  420  of reload  400 . 
     With reference now to  FIGS. 76-81 , reload  400  is configured to selective optional connection with an external irrigation source via an irrigation tube  590 . Irrigation tube  590  is configured to deliver air or saline to the anastomosis site for the purpose of leak testing, for improved insertion or for insulflating the rectal stump. 
     Irrigation tube  590  terminates at a proximal end  590   a  thereof with a proximal luer fitting  591  configured to connect to a syringe (not shown), and at a distal end  590   b  with a distal fitting  592  configured to selectively snap-fit connect to a port  410   c  of housing  410  of reload  400 . Distal fitting  592  includes a pair of resilient fingers  592   a  configured to engage respective shoulders  410   d  defined in port  410   c  of housing  410 . 
     With reference to  FIG. 89 , a schematic diagram of the power handle  101 , the circular adapter assembly  200 , and the reload  400 , is shown. For brevity, only one of the motors  152 ,  154 ,  156  is shown, namely, motor  152 . The motor  152  is 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 the motor  152  are coupled to the motor controller circuit board  142   a  having a motor controller  143  which controls the operation of the motor  152  including the flow of electrical energy from the battery  144  to the motor  152 . The main controller circuit board  142   b  ( FIGS. 12 and 13 ) includes a main controller  147 , which controls the power handle  101 . The motor controller  143  includes a plurality of sensors  408   a ,  408   b , . . .  408   n  configured to measure operational states of the motor  152  and the battery  144 . The sensors  408   a - n  may include voltage sensors, current sensors, temperature sensors, telemetry sensors, optical sensors, and combinations thereof. The sensors  408   a - 408   n  may measure voltage, current, and other electrical properties of the electrical energy supplied by the battery  144 . The sensors  408   a - 408   n  may also measure angular velocity (e.g., rotational speed) as revolutions per minute (RPM), torque, temperature, current draw, and other operational properties of the motor  152 . Angular velocity may be determined by measuring the rotation of the motor  152  or a drive shaft (not shown) coupled thereto and rotatable by the motor  152 . Position of various axially movable drive shafts may also be determined by using various linear sensors disposed in or in proximity to the shafts or extrapolated from the RPM measurements. In embodiments, torque may be calculated based on the regulated current draw of the motor  152  at a constant RPM. In further embodiments, the motor controller  143  and/or the main controller  147  may measure time and process the above-described values as a function of time, including integration and/or differentiation, e.g., to determine the rate of change in the measured values. The main controller  147  is also configured to determine distance traveled of various components of the circular adapter assembly  200  and/or the reload  400  by counting revolutions of the motors  152 ,  154 , and  156 . 
     The motor controller  143  is coupled to the main controller  147 , which includes a plurality of 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 operational status of the motor  152  and the battery  144  and, in turn, outputs control signals to the motor controller  143  to control the operation of the motor  152  based on the sensor readings and specific algorithm instructions, which are discussed in more detail below. The main controller  147  is also configured to accept a plurality of user inputs from a user interface (e.g., switches, buttons, touch screen, etc. coupled to the main controller  147 ). 
     The main controller  147  is also coupled to a memory  141  that is disposed on the main controller circuit board  142   b . 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 gauge  320  of the circular adapter assembly  200  using a wired or a wireless connection and is configured to receive strain measurements from the strain gauge  320  which are used during operation of the power handle  101 . 
     The reload  400  includes a storage device  405  (e.g., chip  464   c ). The circular adapter assembly  200  also includes a storage device  407 . The storage devices  405  and  407  include non-volatile storage medium (e.g., EEPROM) that is configured to store any data pertaining to the reload  400  and the circular adapter assembly  200 , respectively, including but not limited to, usage count, identification information, model number, serial number, staple size, stroke length, maximum actuation force, minimum actuation force, factory calibration data, and the like. In embodiments, the data may be encrypted and is only decryptable by devices (e.g., main controller  147 ) have appropriate keys. The data may also be used by the main controller  147  to authenticate the circular adapter assembly  200  and/or the reload  400 . The storage devices  405  and  407  may be configured in read only or read/write modes, allowing the main controller  147  to read as well as write data onto the storage device  405  and  407 . 
     Operation of the handle assembly  100 , the circular adapter assembly  200 , and the reload  400  is described below with reference to  FIGS. 82A-F , which shows a flow chart of the operation process. With particular reference to  FIG. 82A , the power handle  101  is removed from a charger (not shown) and is activated. The power handle  101  performs a self-check upon activation and if the self-check passes, the power handle  101  displays an animation on the display screen  146  illustrating how the power handle  101  should be inserted into shell housing  10 . 
     After the power handle  101  is inserted into the shell housing  10 , the power handle  101  verifies that it is properly inserted into the shell housing  10  by establishing communications with the electrical connector  66  of the shell housing  10 , which has a chip (not shown) disposed therein. The chip within the electrical connector  66  stores a usage counter which the power handle  101  uses to confirm that the shell housing  10  has not been previously used. The data (e.g., usage count) stored on the chip is encrypted and is authenticated by the power handle  101  prior to determining whether the usage count stored on the chip exceeds the threshold (e.g., if the shell housing  10  has been previously used). 
     With reference to  FIG. 82B , after the power handle  101  is enclosed within the shell housing  10  to form handle assembly  100 , adapter assembly  200  is coupled to handle assembly  100 . After attachment of circular adapter assembly  200 , handle assembly  100  initially verifies that circular adapter assembly  200  is coupled thereto by establishing communications with the storage device  407  of the circular adapter assembly  200  and authenticates circular adapter assembly  200 . The data (e.g., usage count) stored on the storage device  407  is encrypted and is authenticated by the power handle  101  prior to determining whether the usage count stored on the storage device  407  exceeds the threshold (e.g., if the adapter assembly  200  has been previously used). Power handle  101  then performs verification checks (e.g., end of life checks, trocar member  274  missing, etc.) and calibrates circular adapter assembly  200  after the handle assembly  100  confirms that the trocar member  274  is attached. 
     After circular adapter assembly  200  is calibrated, an unused reload  400 , with the shipping cap assembly  401 , is coupled to circular adapter assembly  200 . The handle assembly  100  verifies that circular reload  400  is attached to circular adapter assembly  200  by establishing communications with the storage device  405  of circular reload  400 . With reference to  FIG. 82C , power handle  101  also authenticates the storage device  405  and confirms that circular reload  400  has not been previously fired by checking the usage count. The usage count is adjusted and encoded by handle assembly  100  after use of circular reload  400 . If circular reload  400  has been previously used, handle assembly  100  displays an error indicating the same on the display screen  146 . 
     The power handle  101  also performs calibration with the reload  400  attached to the circular adapter assembly  200  to determine a starting hard stop position. The main controller  147  calculates the distance travelled by the motors  152 ,  154 ,  156  to determine the hard stop. The main controller  147  also utilizes the traveled distance during calibration to confirm that the reload  400  is unused. Thus, if the traveled distance is determined to be above a predetermined hard stop threshold, then the main controller  147  confirms that the staples were previously ejected from the reload  400  and marks the reload  400  as used, if the reload  400  was not properly marked before. Once the anvil assembly  510  is attached, the main controller  147  performs another calibration. 
     With continued reference to  FIG. 82C , upon attaching circular reload  400  and confirming that circular reload  400  is unused and has been authenticated, handle assembly  100  prompts the user to eject the shipping cap assembly  401  by prompting the user to press up on the toggle control button  30 . The prompt is displayed as an animation on the display screen  146  with a flashing arrow pointing toward the toggle control button  30 . The user depresses the upper portion of the toggle control button  30 , which activates an automatic extension (and retraction) of trocar member  274  until the shipping cap assembly  401  is ejected, at which point the shipping cap ejection process is complete and the handle assembly  100  is now ready for use. 
     In embodiments, the circular adapter assembly  200  also operates with reloads  400  having disposable trans-anal/abdominal introducers. Once the reload  400  with the introducer is attached, handle assembly  100  shows a ready screen. This allows the user to insert circular adapter assembly  200  along with the reload  400  more easily through intra-abdominal incisions. Thus, when the toggle control button  30  is pressed, a prompt for ejecting the introducer is displayed, which is similar to the animation for ejecting the shipping cap assembly  401 . The user depresses the upper portion of the toggle control button  30 , which activates an automatic extension (and retraction) of the trocar member  274  until the introducer is ejected, at which point the introducer ejection process is complete. 
     With continued reference to  FIG. 82C , after the shipping cap assembly  401  or the introducer is removed, the user commences a surgical procedure which includes preparing the target tissue area and positioning circular adapter assembly  200  within the colorectal or upper gastrointestinal region or until trocar member  274  extends sufficiently to permit piercing of tissue. The user presses the toggle control button  30  to extend the trocar member  274  until it pierces tissue. While the trocar member  274  is extending, an animation illustrating the extension process is displayed on the display screen  146 . In addition, distance traveled by the trocar member  274  is shown as a scale and the direction of the movement of the trocar member  274  is shown via an arrow. The trocar member  274  is extended until it reaches the maximum extension distance which is indicated on the display screen  146 . 
     With reference to  FIGS. 82C-D  and  86 , which shows a flow chart of the clamping process, after extension of the trocar member  274 , the anvil assembly  510  (already positioned by surgeon) is attached to the trocar member  274  and the user begins the clamping process on the tissue interposed between circular reload  400  and the anvil assembly  510  by pressing on the bottom of the toggle control button  30 . The clamping process is also shown as an animation on the display screen  146 , but as a reverse of the animation of the extension of the trocar member  274 , e.g., an arrow is highlighted illustrating the retraction direction. 
     During clamping, the anvil assembly  510  is retracted toward the circular reload  400  until reaching a fully compressed position, namely position of the anvil assembly  510  at which the tissue is fully compressed between the anvil assembly  510  and the reload  400 . Fully compressed distance varies for each of the different types of reloads (e.g., the distance is about 29 mm for 25 mm reloads). While clamping, the strain gauge assembly  320  continuously provides measurements to the main controller on the force imparted on the first rotation transmitting assembly  240  as it moves the anvil assembly  510 . 
     With reference to  FIG. 83 , which schematically illustrates the travel distance and speed of the anvil assembly  510  as it is retracted by the first motor  152 , the anvil assembly  510  is initially retracted from a full open position marker  600  at a first speed for a first segment from the full open position marker  600  to a first distance marker  602 . Thereafter, the anvil assembly  510  traverses a second distance from the first distance marker  602  to a second distance marker  604  at the second speed, which is slower than the first speed. As the anvil assembly  510  is traversing the second segment, the main controller  147  continuously verifies whether the measured force is within predefined parameters to determine if the measured force exceeds a high force threshold limit prior to reaching a starting compression distance ( FIGS. 83 and 86 ). This measurement is used to detect misalignment of the splines  586  of trocar member  274  with longitudinally extending ridges  416  of the reload  400 . If the force is higher than the high force threshold, then the power handle  101  temporarily reverses the rotation transmitting assembly  240  to retract the anvil assembly in an attempt to correct the misalignment of the splines  586 . The main controller  147  then reattempts to continue clamping until a third distance marker  604  is reached. If the third distance marker  604  is not reached within a predetermined period of time, the main controller  147  then issues an error, including an alarm on the display screen  146  prompting the user to inspect the anvil assembly  510 . After inspection and clearance of any obstruction, the user may then restart the clamping process. 
     Once the anvil assembly  510  reaches the third distance marker  604  at the end of the second segment, the power handle  101  performs a rotation verification to check position of the anvil assembly  510 . Then the main controller commences a controlled tissue compression (“CTC”) algorithm which varies the clamping speed during tissue compression without exceeding a target compression force. 
     The CTC accounts for slow-changing and rapid-changing forces imparted on the tissue during compression with a second-order predictive force filter. As the predicted force approaches the target force, the clamping speed is slowed to prevent over-shoot. When the measured force reaches the target force and the clamp gap has not yet been achieved, clamping is stopped to allow for tissue relaxation. During tissue relaxation, after the measured force falls below the target clamping force, the CTC recommences. The force exerted on tissue is derived from the strain measurements by the main controller  147  from the strain gauge assembly  320 . 
     During CTC, the user continues to press down on the toggle control button  30  to continue operation of handle assembly  100 . The third distance marker  604 , at which the controller commences the CTC, corresponds to the distance at which the anvil assembly  510  begins to compress the tissue against the staple guide of the circular reload  400  for the remainder of the clamping process. CTC controls the movement of the anvil assembly  510  during a third segment, from the third distance marker  604  to a fourth distance marker  606 , which corresponds to the fully compressed position of the anvil assembly  510 . CTC continues until the anvil assembly  510  reaches the fourth distance marker  606 . During clamping, if no forces are detected, the handle assembly  100  identifies that the anvil assembly  510  is missing and the handle assembly  100  issues an error. 
     The CTC is run for a predetermined time period, namely, a first time period, and an optional second time period. During execution of the CTC, the main controller monitors force based on strain as measured by the strain gauge assembly  320  that is imparted on the first rotation transmitting assembly  240  as it moves the anvil assembly  510  until the measured force approaches the target clamping force. 
     During execution of the CTC, the main controller  147  determines whether the measured forces approaches the target clamping force by calculating a predicted clamping force using a second-order predictive filter. Target clamping force may be any suitable threshold from about 100 pounds to about 200 pounds, in embodiments, the target clamping force may be approximately 150 pounds. The CTC calculates a predicted clamping force and compares it to the target clamping force. The main controller samples a plurality of strain gauge values at predetermined frequency (e.g., every 1 millisecond) during a predetermined sampling time period. The main controller  147  then uses a first plurality of strain gauge samples obtained during the sampling time period to calculate a filtered strain gauge value. The main controller  147  stores a plurality of filtered strain gauge values and uses three strain gauge samples to predict the target clamping force. In particular, the main controller  147  initially calculates a first difference between the first two (e.g., first and second) filtered strain gauge values, which provides a first-order comparison. More specifically, the main controller  147  then calculates a second difference between subsequent two filtered strain gauge values (e.g., second and third values). In embodiments, the subsequent filtered strain gauge values may be any other subsequent values, rather than encompassing the second value used to calculate the first difference. The first difference is then divided by the second difference, to obtain a percentage of the difference. The main controller determines the target clamping force based on a predicted strain change, which is calculated by multiplying the first difference by the percentage of the difference and a value representing future periods of strain extrapolation. The predicted strain change is then added to the current filtered strain gauge value to determine a predicted strain value, which corresponds to the predicted clamping force. 
     If the predicted clamping force is above the target force, the PWM voltage driving the motor  152 , which is driving the first rotation transmitting assembly  240  is set to zero. The force is continued to be monitored, and once the force drops below a target threshold, the speed of the motor  152  is set to an updated speed to continue the clamping process. This process repeats until the fourth distance marker  606  is reached. 
     The target speed is calculated by the main controller  147  based on a strain ratio. The strain ratio is calculated by subtracting the predicated strain value from the target clamping force and dividing the difference by the target clamping force. The strain ratio is then used to determine a speed offset by multiplying a difference between maximum and minimum speeds of the motor  152  by the strain ratio. The speed offset is then added to the minimum speed of the motor  152  to determine the target speed. The target speed is used to control the motor  152  in response to the motor deviating by a predetermined amount from currently set speed (e.g., if the motor  152  deviates by about 50 revolutions per minute). In addition, the motor  152  is set to a newly calculated target speed, if the current speed of the motor  152  is zero, e.g., following the predicted clamping force approaching the target force. This allows for varying the speed of the motor  152  while maintaining the desired force on the tissue during clamping. 
     The target clamping force is fixed for the first time period. When thick tissue is encountered, the clamp gap may not be attained within the first time period (e.g., reaching the fourth distance marker  606 ), clamping is stopped and the operator is notified via the display screen. If the operator chooses to continue the clamping operation, CTC continues to operate for the second time period, during which the target clamping force is incremented until the maximum force is reached. During the second period, clamping movement distance is monitored to determine if the anvil assembly  510  is moved in response to incremental force increases. Thereafter, the clamp distance is periodically monitored for any minimal movement. If no minimal movement is detected, the target force is dynamically incremented by a proportional amount based on a difference between the current clamp position and the fourth distance marker  606 . If a maximum force, which is higher than the target clamping force, is detected, all clamping is stopped. In addition, if clamping is not achieved within the second time period, then the CTC issues an alarm. This may include instructing the user on the display screen  146  to check the clamp site for obstructions. If none are found, the user may continue the clamping process. If the clamping is not complete, e.g., second time period expires and/or the maximum force limit is reached, another alarm is triggered, instructing the user to check tissue thickness and to use a larger reload  400  to restart the clamping process. 
     With reference to  FIGS. 82C-D  and  86 , once CTC is commenced, the display screen  146  displays a CTC user interface after the main controller  147  confirms that the anvil assembly  510  is present based on detection of a minimum force. In particular, the distance scale on the display screen  146  is replaced with a gauge illustrating the force being imparted on the tissue, and the trocar is replaced with the anvil and tissue being compressed. Also displayed is the progress of the clamping until the fourth distance marker  606  is reached. Thus, as the anvil assembly  510  is being moved to compress the tissue under the CTC, the gauge, the anvil animation, and the distance traveled by the anvil assembly  510  are updated continuously to provide real time feedback regarding the CTC progress. 
     During CTC, the strain gauge assembly  320  continuously provides measurements to the main controller on the force imparted on the first rotation transmitting assembly  240  as it moves the anvil assembly  510 . The force measured by the strain gauge assembly  320  is represented by the gauge on the display screen  146 , which is separated into three zones, zone  1  shows the force from 0% to 50% of the target clamp force, zone  2  shows the force from 51% to 100%, and zone  3  shows the maximum force above the target clamp force. High force caution graphic is displayed on screen for zone  3 , the user is required to perform a second activation of the toggle to confirm clamping despite zone  3  high forces. 
     The user can then press the toggle control button  30  to re-clamp, which would move the anvil assembly  510  until the force reaches the maximum force limit of zone  3 . This allows for further compression of the tissue in certain circumstances where the user deems it necessary, e.g., based on tissue thickness. Once the CTC algorithm is complete and tissue is compressed, handle assembly  100  activates an LED and issues a tone indicating the same and the CTC screen indicating 100% compression is continuously displayed on the display screen  146  until the stapling sequence is started. A pre-fire calibration is performed prior to commencement of the stapling sequence. 
     With reference to  FIG. 82D and 87A -B, to initiate stapling sequence, the user presses one of the safety buttons  36   a  or  36   b  of the power handle  101 , which acts as a safety and arms the toggle control button  30 , allowing it to commence stapling. Upon activation of the safety button  36   a  or  36   b , a second rotation verification calibration check is performed. The display screen  146  transitions to the stapling sequence display, which includes a circle illustrating an animated view of a circular anastomosis, a progress bar, and a staple icon. The stapling sequence screen is displayed until user initiates the stapling sequence, exits the stapling sequence, or unclamps. At the start of the stapling sequence, the LED begins to flash and an audio tone is played. The LED continues to flash throughout the duration of the stapling and cutting sequences. 
     To commence the stapling sequence, the user presses down on the toggle control button  30 , which moves the second rotation transmitting assembly  250  to convert rotation to linear motion and to eject and form staples from circular reload  400 . In particular, during the firing sequence, the second motor  152  advances the driver  434  using the second rotation transmitting assembly  250 . The force imparted on the second rotation transmitting assembly  250  is monitored by the strain gauge assembly  320 . The process is deemed complete once the second rotation transmitting assembly  250  reaches a hard stop corresponding to a force threshold and detected by the strain gauge assembly  320 . This indicates that the staples have been successfully ejected and deformed against the anvil assembly  510 . 
     With reference to  FIG. 84 , which schematically illustrates the travel distance and speed of the second motor  154  as it advances the driver  434 , driver  434  is initially advanced from a first position marker  608  (e.g., hardstop) at a first speed for a first segment from the first distance marker  608  to a second distance marker  610 . From the second distance marker  610 , the driver  434  is advanced at a second speed, slower than the first speed, until it reaches a third distance marker  612 , to eject the staples. 
     During the first segment, the second motor  154  advances the driver  434  until the driver  434  contacts the staples to commence firing. The main controller  147  also writes to the storage devices  405  and  407  of the reload  400  and the circular adapter assembly  200 . In particular, main controller  147  marks the reload  400  as “used” in the storage device  405  and increments the usage count in the storage device  407  of the circular adapter assembly  200 . 
     After reaching the second distance marker  610 , the second motor  154  is operated at the second, slower speed to eject the staples from the reload  400 . With reference to  FIG. 87B , during the second segment, as the staples are ejected from the reload  400  to staple tissue, the main controller  147  continually monitors the strain measured by the strain gauge assembly  320  and determines whether the force corresponding to the measured strain is between a minimum stapling force and a maximum stapling force. The stapling force range may be stored in the storage device  405  of the reload  400  and used by the main controller  147  during the stapling sequence. Determination whether the measured force is below the minimum stapling force is used to verify that the staples are present in the reload  400 . In addition, a low force may be also indicative of a failure of the strain gauge  320 . If the measured force is below the minimum stapling force, then the main controller  147  signals the second motor  154  to retract the driver  434  to the second distance marker  610 . The main controller  147  also displays a sequence on the display  146  instructing the user the steps to exit stapling sequence and retract the anvil assembly  510 . After removing the anvil assembly  510 , the user may replace the circular adapter assembly  200  and the reload  400  and restart the stapling process. 
     If the measured force is above the maximum stapling force, which may be about  500  lbs., the main controller  147  stops the second motor  154  and displays a sequence on the display  146  instructing the user the steps to exit the stapling sequence. However, the user may still continue the stapling process without force limit detection by pressing on toggle control button  30 . 
     The main controller  147  determines that the stapling process is completed successfully, if the second motor  154  reached a third distance marker  612  associated with stapled tissue and during this movement the measured strain was within the minimum and maximum stapling force limits. Thereafter, the second motor  154  retracts the driver  434  to a fourth distance marker  614  to release pressure on the tissue and subsequently to the second distance marker  610  prior to starting the cutting sequence. 
     The main controller  147  is also configured to account for band compression of outer flexible band assembly  255  during the stapling process which may result in a non-linear relationship between motor position as determined by the main controller  147  and position of components of the circular adapter assembly  200 . The main controller  147  is configured to resolve the discrepancy between the calculated position of the motors  152 ,  154 ,  156  and the actual position of the components of the circular adapter assembly  200  using a second order mapping of force changes that result in the discrepancies. The force changes are based on the strain measurements from the strain gauge assembly  320 . In particular, the main controller  147  maintains a count of lost turns by the motors  152 ,  154 ,  156 , namely, turns that did not result in movement of the components of the circular adapter assembly  200 , e.g., due to compression, based on the force imparted on the components of the circular adapter assembly  200 . The main controller  147  accumulates the total lost turns each time the imparted force changes by a predetermined amount, e.g., about 5 lbs. The motor position is then adjusted by the total accumulated lost-turns value to determine whether the target position has been attained. 
     With reference to  FIG. 82D , progress of staple firing is illustrated by an animation of the anastomosis, the firing progress bar, and staple formation. In particular, the animation illustrates staple legs penetrating tissue and then forming to create concentric staple lines. Once the stapling sequence is complete, the outer circumference is displayed in green. The staple icon also shows initially unformed staples, and then shows the legs of the staples being curled inward. The progress bar is separated into two segments, the first segment being indicative of the stapling process and the second segment being indicative of the cutting process. Thus, as the stapling sequence is ongoing the progress bar continues to fill until it reaches its midpoint. 
     With reference to  FIGS. 82E and 88A -B, after the stapling sequence is complete, the power handle  101  automatically commences the cutting sequence. During the cutting sequence, the third motor  154  advances the knife assembly  440  using the third rotation transmitting assembly  260 . The force imparted on the third rotation transmitting assembly  260  is monitored by the strain gauge assembly  320 . The process is deemed complete once the third rotation transmitting assembly  260  reaches a hard stop corresponding to a force threshold and detected by the strain gauge assembly  320  or a maximum position is reached. This indicates that the knife assembly  320  has cut through the stapled tissue. 
     With reference to  FIG. 85 , which schematically illustrates the travel distance and speed of the third motor  156  as it advances the knife assembly  440 . The knife assembly  440  is initially advanced from a first position marker  616  at a first speed for a first segment from the first distance marker  616  until a second distance marker  618 . From the second distance marker  618 , the knife assembly  440  is advanced at a second speed, slower than the first speed, until it reaches a third distance marker  620 , to cut the stapled tissue. 
     During the first segment, the third motor  156  advances the knife assembly  440  until the knife assembly  440  contacts the stapled tissue. After reaching the second distance marker  618 , the third motor  154  is operated at the second, slower speed to cut the stapled tissue. With reference to  FIGS. 88A-B , during the second segment, as the knife assembly  440  is advanced to cut tissue, the main controller  147  continually monitors the strain measured by the strain gauge assembly  320  and determines whether the force corresponding to the measured strain is between a target cutting force and a maximum cutting force. The target cutting force and the maximum cutting force may be stored in the storage device  405  of the reload  400  and used by the main controller  147  during cutting sequence. If the target cutting force is not reached during the cutting sequence, which is indicative of improper cutting, then the main controller  147  signals the third motor  156  retract the knife assembly  440  allowing the user to open the reload  400  and abort the cutting sequence. The main controller  147  also displays a sequence on the display  146  indicating to the user the steps to exit the cutting sequence and retract the anvil assembly  510 . After removing the anvil assembly  510 , the user may replace the circular adapter assembly  200  and the reload  400  and restart the stapling process. If the measured force is above the maximum cutting force, the main controller  147  stops the third motor  156  and displays a sequence on the display  146  instructing the user to exit the cutting sequence. 
     The main controller  147  determines that the stapling process is completed successfully, if the knife assembly  440  being moved by the third motor  156  reached a third distance marker  620  associated with cut tissue and during this movement the measured strain was within the target and maximum cutting force limits. Thereafter, the third motor  154  retracts the knife assembly  440  back to the first distance marker  616 . 
     Each of the distance markers  600 - 620  are stored in the memory  141  and/or the storage device  405  and are used by the main controller  147  to control the operation of the power handle  101  to actuate various components of the circular adapter assembly  200  based thereon. As noted above the distance markers  600 - 620  may be different for different type of reloads accounting for variations in staple size, diameter of the reload, etc. In addition, the distance markers  600 - 620  are set from the hard stop as determined during the calibration process described above. 
     With reference to  FIG. 82E , the cutting sequence is illustrated by the same user interface, except the staple icon is grayed out and a knife icon is highlighted. During the cutting sequence, the knife icon is animated with motion and the progress bar moves from its midpoint to the right. In addition, the inner circumference of the circle is displayed in green once the cutting sequence is complete. During the cutting sequence the force imparted on the third rotation transmitting assembly  260  is monitored by the strain gauge assembly  320  to ensure that maximum force limit is not exceeded. The process is deemed complete once the third rotation transmitting assembly  260  reaches a hard stop or a force threshold as detected by the strain gauge assembly  320 . This indicates that the knife has successfully dissected the tissue. Completion of the cutting sequence is indicated by another tone and the LED stops flashing and remains lit. 
     With reference to  FIG. 82F , after the stapling and cutting sequences are complete, the user begins an unclamping sequence to release the anvil assembly  510  from the trocar member  274  by pressing on the top of the toggle control button  30 . As the toggle control button  30  is pressed up, the trocar member  274  is automatically extended distally, thereby moving the anvil assembly  510  away from circular reload  400  and unclamping the tissue to the preset anvil tilt distance. The unclamping sequence is illustrated on the display screen  146 . In particular, an unclamping animation shows the anvil assembly  510  moving distally and the head assembly  512  being tilted. In addition, the display screen  146  also shows a lock icon to show that the anvil assembly  510  is secured to the trocar member  274 . Once the anvil assembly  510  is moved away from circular reload  400  to its tilt distance, the display screen  146  shows the anvil assembly  510  in the extended state with the head assembly  512  in the tilted state. This indicates that the user may remove the circular adapter assembly  200  from the patient. The LED then turns off. Once circular adapter assembly  200  is removed, the user then may unlock the anvil assembly  510  from the trocar member  274  by pressing one of the left-side or right-side control buttons  32   a ,  32   b ,  34   a ,  34   b  of the of the power handle  101  for a predetermined period of time (e.g.,  3  seconds or more). The display screen  146  shows which button needs to be pressed on the power handle  101  to unlock the anvil assembly  510 . As the user is pressing one of the control buttons  32   a ,  32   b ,  34   a ,  34   b , the display screen  146  displays a countdown (e.g., 3, 2, 1) and the lock icon is shown to be in the unlocked state. At this point, the anvil assembly  510  is unlocked and may be removed. The user may then remove reload  400  as well as the severed tissue from the resection procedure. Circular adapter assembly  200  is also detached from handle assembly  100  and is cleaned and sterilized for later reuse. The shell housing  10  is opened and discarded, with the power handle  101  being removed therefrom for reuse. 
     The powered stapler according to the present disclosure is also configured to enter recovery states during the clamping, stapling, and cutting sequences if any of the components, e.g., the power handle  101 , circular adapter assembly  200 , circular reload  400 , and/or the anvil assembly  510 , encounter errors. The recovery states are software states executed by main controller  147  that guide the user through correcting and/or troubleshooting the errors and allow the user to resume any of the clamping, stapling, and cutting sequences once the error is corrected. 
     At the start of each operational sequence (e.g, clamping, stapling, firing, etc.), the main controller  147  writes to the storage device  407  of the circular adapter assembly  200  a recovery code associated with the operational sequence. Thus, at the start of the procedure the storage device  407  stores an initialization recovery code indicating that the circular adapter assembly  200  has not yet been used. However, as the circular adapter assembly  200  is used throughout the procedure, namely, progressing through the different sequences described above, corresponding recovery codes are written to the storage device  407 . In addition, the main controller  147  writes corresponding recovery states to the memory  141 . In either instance, this allows for replacement of either of the adapter assembly  200  and/or the power handle  101  depending on the error state as both of the components store the last recovery state locally, namely, in the storage device  407  or the memory  141 , respectively. 
     With reference to  FIG. 87A , which shows a recovery procedure during the stapling sequence and  FIG. 88A , which shows a recovery procedure during the cutting sequence, during the procedure there may be instances that the power handle  101  identifies a flaw with one or more of the components of the power handle  101 , the circular adapter assembly  200 , and/or the reload  400 . These recovery procedures are illustrative and similar procedures are also envisioned to be implemented in other operational sequences of the power handle  101 , e.g., clamping sequence. The recovery procedures may include, but are not limited to, attaching a new power handle  101  to an adapter assembly  200  that is inserted into the patient, replacing the adapter assembly  200  and/or the reload  400 . 
     When an adapter assembly  200  is attached to the power handle  101 , the power handle  101  reads the recovery code from the storage device  407  to determine the state of the adapter assembly  200 . The recovery code was written when the adapter assembly  200  was previously detached from the power handle  101 . As noted above, at the start of the procedure, the recovery cod indicates the initial state, which directs the power handle  101  to transition into start-up sequence, e.g., calibration. If the adapter assembly  200  was detached in the middle of the procedure, e.g., clamping, stapling, cutting, etc., the corresponding recovery code provides the entry point back into the mainline flow after performing a recovery procedure. This allows the operator to continue the surgical procedure at the point where the adapter assembly  200  was originally detached. 
     Similarly, in situations where the power handle  101  is being replaced, a new power handle  101  is configured to read the recovery state from the adapter assembly  200 . This allows the new power handle  101  to resume operation of the previous power handle  101 . Thus, during any of the operational sequences, e.g., clamping, stapling, and cutting, the adapter assembly  200  may be left in the corresponding configuration, e.g., clamped, stapled, etc., and after the new power handle  101  is attached, operation may be resumed. 
     It will be understood that various modifications may be made to the embodiments of the presently disclosed adapter assemblies. Therefore, 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.