Patent Description:
Examples of surgical instruments include surgical staplers. Some such staplers are operable to clamp down on layers of tissue, cut through the clamped layers of tissue, and drive staples through the layers of tissue to substantially seal the severed layers of tissue together near the severed ends of the tissue layers. Examples of surgical staplers and associated features are disclosed in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

While several surgical instruments and systems have been made and used, it is believed that no one prior to the inventors has made or used the invention described in the appended claims.

<CIT> provides surgical tools and related methods that articulate an actuation rod assembly via an actuation tension member. The surgical tool includes an end effector, an instrument shaft assembly supporting the end effector, an actuation rod assembly drivingly coupled with the end effector, a guide surface, a flexible tension member connected to the actuation rod assembly, and an actuation portion. The actuation rod assembly is mounted to slide within the instrument shaft assembly. The flexible tension member is connected to the actuation rod assembly at a connection.

<CIT> provides various surgical tools with bailout mechanisms are provided that allow direct engagement with one or more actuators to provide rapid and effective bailout (such as release, reversal, and/or retraction) of surgical tools while minimizing the amount of force and/or time to complete the bailout.

Other examples, features, aspects, embodiments, and advantages of the technology will become apparent to those skilled in the art from the following description, which is by way of illustration, one of the best modes contempl ated for carrying out the technology.

Such modifications and variations are intended to be included within the scope of the claims, as long as they fall thereunder.

For clarity of disclosure, the terms "proximal" and "distal" are defined herein relative to a human or robotic operator of the surgical instrument. The term "proximal" refers the position of an element closer to the human or robotic operator of the surgical instrument and further away from the surgical end effector of the surgical instrument. The term "distal" refers to the position of an element closer to the surgical end effector of the surgical instrument and further away from the human or robotic operator of the surgical instrument. It will be further appreciated that, for convenience and clarity, spatial terms such as "clockwise," "counterclockwise," "inner," "outer," "upper," "lower," and the like also are used herein for reference to relative positions and directions. Such terms are used below with reference to views as illustrated for clarity and are not intended to limit the invention described herein.

Aspects of the present examples described herein may be integrated into a robotically-enabled medical system, including as a robotic surgical system, capable of performing a variety of medical procedures, including both minimally invasive, such as laparoscopy, and non-invasive, such as endoscopy, procedures. Among endoscopy procedures, the robotically-enabled medical system may be capable of performing bronchoscopy, ureteroscopy, gastroscopy, etc..

<FIG> shows a top plan view of an exemplary robotic surgical system (<NUM>) that may be used for performing a diagnostic or surgical procedure on a patient (<NUM>) who is lying down on an operating table (<NUM>). Robotic surgical system (<NUM>) may be constructed and operable in accordance with at least some of the teachings of <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and/or <CIT>.

Robotic surgical system (<NUM>) may include a surgeon's console (<NUM>) for use by a surgeon (<NUM>) during a surgical procedure. One or more assistants (<NUM>) may also participate in the procedure. Robotic surgical system (<NUM>) may include a patient side cart (<NUM>) (i.e., a surgical robot) and an electronics cart (<NUM>). Patient side cart (<NUM>) may manipulate at least one surgical instrument (<NUM>) (also referred to as a "tool assembly" or "tool") through an incision in the body of patient (<NUM>) while surgeon (<NUM>) views the surgical site through surgeon's console (<NUM>). As will be described in greater detail below, surgical instrument(s) (<NUM>) and an imaging device (shown as an endoscope (<NUM>)) may be removably coupled with patient side cart (<NUM>). Electronics cart (<NUM>) may be used to process the images of the surgical site for subsequent display to the surgeon (<NUM>) through surgeon's console (<NUM>). Electronics cart (<NUM>) may be coupled with endoscope (<NUM>) and may include a processor (<NUM>) (shown schematically) to process captured images for subsequent display, such as to surgeon (<NUM>) on the surgeon's console (<NUM>), on a display (<NUM>) of electronics cart (<NUM>), or another suitable display located locally and/or remotely. The images may also be processed by a combination of electronics cart (<NUM>) and processor (<NUM>), which may be coupled together to process the captured images jointly, sequentially, and/or combinations thereof. Electronics cart (<NUM>) may overlay the captured images with a virtual control interface prior to displaying combined images to the surgeon (<NUM>) via surgeon's console (<NUM>).

<FIG> shows a perspective view of surgeon's console (<NUM>). Surgeon's console (<NUM>) includes a left eye display (<NUM>) and a right eye display (<NUM>) for presenting surgeon (<NUM>) with a coordinated stereo view of the surgical site that enables depth perception. Surgeon's console (<NUM>) includes one or more input control devices (<NUM>) causing patient side cart (<NUM>) (shown in <FIG>) to manipulate one or more surgical instruments (<NUM>). Input control devices (<NUM>) may provide the same degrees of freedom as their associated surgical instruments (<NUM>) (shown in <FIG>) to provide surgeon (<NUM>) with telepresence, or the perception that the input control devices (<NUM>) are integral with surgical instruments (<NUM>). To this end, position, force, and tactile feedback sensors (not shown) may be employed to transmit position, force, and tactile sensations from surgical instruments (<NUM>) back to the surgeon's hands through input control devices (<NUM>). In some instances, surgeon's console (<NUM>) may be located in the same room as the patient so that surgeon (<NUM>) may directly monitor the procedure, be physically present if necessary, and speak to an assistant directly rather than over the telephone or other communication medium. Alternatively, surgeon (<NUM>) may be located in a different room, a completely different building, or other remote location from the patient allowing for remote surgical procedures.

<FIG> shows patient side cart (<NUM>) that manipulates surgical instruments (<NUM>). An image of the surgical site may be obtained by endoscope (<NUM>), which may include a stereoscopic endoscope. Manipulation is provided by robotic mechanisms, shown as robotic arms (<NUM>) that include at least one robotic joint (<NUM>) and an output coupler (not shown) that is configured to removable secure surgical instrument (<NUM>) with robotic arm (<NUM>). Endoscope (<NUM>) and surgical tools (<NUM>) may be positioned and manipulated through incisions in the patient so that a kinematic remote center is maintained at the incision to minimize the size of the incision. Images of the surgical site may include images of the distal ends of the surgical instruments (<NUM>) when they are positioned within the field-of-view of the endoscope (<NUM>). Patient side cart (<NUM>) may output the captured images for processing outside electronics cart (<NUM>). The number of surgical instruments (<NUM>) used at one time will generally depend on the diagnostic or surgical procedure and the space constraints within the operating room, among other factors. To change one or more of surgical instruments (<NUM>) being used during a procedure, assistant(s) (<NUM>) may remove surgical instrument (<NUM>) from patient side cart (<NUM>) and replace surgical instrument (<NUM>) with another surgical instrument (<NUM>) from a tray (<NUM>) (shown in <FIG>) in the operating room.

<FIG> show an exemplary surgical instrument (<NUM>) that may be mounted on and used with patient side cart (<NUM>) shown in <FIG>. Surgical instrument (<NUM>) can have any of a variety of configurations capable of performing one or more surgical functions. As shown, surgical instrument (<NUM>) includes an instrument base (<NUM>), a shaft assembly (<NUM>) extending distally from instrument base (<NUM>), and an end effector (<NUM>) at a distal end of shaft assembly (<NUM>). Instrument base (<NUM>) includes an attachment interface (<NUM>) that includes input couplers (<NUM>) that are configured to interface with and be driven by corresponding output couplers (not shown) of robotic arm (<NUM>) of patient side cart (<NUM>).

<FIG> shows an enlarged perspective view of instrument base (<NUM>) of surgical instrument (<NUM>). Instrument base (<NUM>) includes a drive system (<NUM>) mounted on a chassis (<NUM>) and having one or more actuators for actuating end effector (<NUM>) to clamp, staple, and cut tissue, and for articulating end effector (<NUM>) relative to a longitudinal axis defined by shaft assembly (<NUM>). Drive system (<NUM>) may include a manual actuator (<NUM>), which is shown in the form of a knob configured to be manually rotated. Manual actuator (<NUM>) may engage other components of surgical instrument (<NUM>) to serve as a "bailout" mechanism to obtain a desired movement in end effector (<NUM>) without powered actuation of drive system (<NUM>). Shaft assembly (<NUM>) may include additional drive components, such as portions of a drive train (<NUM>), that may couple instrument base (<NUM>) to a moveable feature (<NUM>) of shaft assembly (<NUM>) that may be coupled to end effector (<NUM>). Shaft assembly (<NUM>) may be configured for use with a variety of interchangeable end effectors (<NUM>), such as a cutter, grasper, a cautery tool, a camera, a light, or a surgical stapler, for example.

<FIG> shows a cross-sectional side view of end effector (<NUM>) of surgical instrument (<NUM>). End effector (<NUM>) extends distally from a distal end of shaft assembly (<NUM>). In the present example, end effector (<NUM>) comprises a surgical stapler, which may also be referred to herein as an "endocutter," configured to clamp, cut, and staple tissue. As illustrated, end effector (<NUM>) includes opposing upper and lower jaws (<NUM>, <NUM>) configured to move relative to one another between open and closed positions for clamping and releasing tissue.

One or both of upper and lower jaws (<NUM>, <NUM>) may be configured to pivot and thereby actuate end effector (<NUM>) between open and closed positions. Lower jaw (<NUM>) includes a removable staple cartridge (<NUM>). In the illustrated example, lower jaw (<NUM>) is pivotable relative to upper jaw (<NUM>) to move between an open, unclamped position and a closed, clamped position. In other examples, upper jaw (<NUM>) may move relative to lower jaw (<NUM>) (e.g., similar to end effector (<NUM>) of <FIG>). In still other examples, both and upper and lower jaws (<NUM>, <NUM>) may move to actuate end effector (<NUM>) between open and closed positions. In the present example, lower jaw (<NUM>) is referred to as a "cartridge jaw" or "channel jaw," and upper jaw (<NUM>) is referred to as an "anvil jaw.

Upper jaw (<NUM>) defines a surface that has a plurality of pockets (not shown) and operates as an anvil to deform staples ejected from staple cartridge (<NUM>) during operation. Staple cartridge (<NUM>) is replaceable, for example, by removing a used staple cartridge (<NUM>) from end effector (<NUM>) and inserting a new staple cartridge (<NUM>) into lower jaw (<NUM>). Staple cartridge (<NUM>) includes a staple cartridge body (<NUM>) that houses a firing assembly (<NUM>), a plurality of staple drivers (<NUM>) (also referred to as staple pushers), and a plurality of staples (<NUM>). As shown in <FIG> and <FIG>, end effector (<NUM>) includes a driving assembly (<NUM>) that includes a pusher member (<NUM>) that is operatively coupled with an actuation mechanism via a push rod (<NUM>). As shown in <FIG> and <FIG>, firing assembly (<NUM>) includes a wedge sled (<NUM>) (also referred to as a staple pushing shuttle), and a knife member (<NUM>).

<FIG> shows a top view of staple cartridge body (<NUM>). Staple cartridge body (<NUM>) includes an array of staple accommodating apertures (<NUM>) (also known as openings) extending through an upper deck (<NUM>) of staple cartridge body (<NUM>). Each aperture (<NUM>) slidably houses a respective staple (<NUM>) in an unformed state and a free end of a corresponding staple driver (<NUM>) positioned beneath the unformed staple (<NUM>). Staple cartridge (<NUM>) includes proximal and distal ends (<NUM>, <NUM>). In operation, staples (<NUM>) are sequentially deployed from apertures (<NUM>) by staple drivers (<NUM>) starting at proximal end (<NUM>) and advancing toward distal end (<NUM>). A vertical slot (<NUM>), configured to accommodate knife member (<NUM>), extends through part of staple cartridge (<NUM>).

<FIG> shows pusher member (<NUM>) as including first and second flanges (<NUM>, <NUM>). First flange (<NUM>) is configured to be received in a longitudinal slot (<NUM>) (shown in <FIG>) of upper jaw(<NUM>) and second flange (<NUM>) is configured to be received in a longitudinal slot (<NUM>) (shown in <FIG>) of staple cartridge body (<NUM>) of lower jaw (<NUM>). First and second flanges (<NUM>, <NUM>) move along longitudinal slots (<NUM>, <NUM>) during actuation of pusher member (<NUM>). In some versions, pusher member (<NUM>) may include a single flange (e.g., omitting first flange (<NUM>)). As shown, longitudinal slot (<NUM>) is generally enclosed and longitudinal slot (<NUM>) opens to an exterior surface of lower jaw (<NUM>).

<FIG> shows a perspective view of firing assembly (<NUM>), which is configured to be slidably received within the proximal end of staple cartridge body (<NUM>) in a longitudinal direction prior to engaging staple drivers (<NUM>) and staples (<NUM>). Wedge sled (<NUM>) of firing assembly (<NUM>) slidingly interfaces with staple cartridge body (<NUM>). More specifically, wedge sled (<NUM>) advances distally along staple cartridge body (<NUM>) such that ramp portions (<NUM>) of wedge sled contact staple drivers (<NUM>). Staple drivers (<NUM>) push staples (<NUM>) out of apertures (<NUM>) of staple cartridge body (<NUM>) to penetrate through and staple tissue clamped between staple cartridge body (<NUM>) and upper jaw (<NUM>). An initial distal actuation of pusher member (<NUM>) may move pusher member (<NUM>) into contact with wedge sled (<NUM>), with further actuation pushing staples (<NUM>) transversely out of staple cartridge body (<NUM>).

At an initial proximal position of wedge sled (<NUM>), knife member (<NUM>) is housed within staple cartridge body (<NUM>). The position of knife member (<NUM>) is controlled during a first portion of the movement of wedge sled (<NUM>) from proximal end (<NUM>) of staple cartridge body (<NUM>) to distal end (<NUM>) of staple cartridge (<NUM>), so that a cutting edge (<NUM>) of knife member (<NUM>) extends through vertical slot (<NUM>). Vertical slot (<NUM>) accommodates cutting edge (<NUM>) of knife member (<NUM>) as firing assembly (<NUM>) is moved toward distal end (<NUM>) of staple cartridge (<NUM>). Wedge sled (<NUM>) includes a guide member (<NUM>) that provides a bearing surface that cooperates with a similarly shaped surface of staple cartridge body (<NUM>) to guide wedge sled (<NUM>). Guide member (<NUM>) extends from a vertical rib member (<NUM>) of wedge sled (<NUM>), which forms a central portion of wedge sled (<NUM>). In some versions, knife member (<NUM>), or at least cutting edge (<NUM>), may be retracted below upper deck (<NUM>) of staple cartridge body (<NUM>) prior to firing assembly (<NUM>) reaching its distal most position adjacent to distal end (<NUM>) of staple cartridge (<NUM>).

<FIG> show a second exemplary end effector (<NUM>), in an open position, that is configured to compress, cut, and staple tissue. End effector (<NUM>) may be configured for use with surgical instrument (<NUM>) of <FIG>, or with surgical instruments of alternative constructions. End effector (<NUM>) may be constructed and operable in accordance with at least some of the teachings of <CIT>. End effector (<NUM>) of the present example includes a lower jaw (<NUM>) and an upper jaw in the form of a pivotable anvil (<NUM>). Lower jaw (<NUM>) may be constructed and operable in accordance with at least some of the teachings of <CIT>. Anvil (<NUM>) may be constructed and operable in accordance with at least some of the teachings of <CIT>.

<FIG> shows end effector (<NUM>), where anvil (<NUM>) is pivoted to an open position and a firing beam (<NUM>) is proximally positioned, allowing an unspent staple cartridge (<NUM>) to be removably installed into a channel of lower jaw (<NUM>). Staple cartridge (<NUM>) includes a cartridge body (<NUM>), which presents an upper deck (<NUM>) and is coupled with a lower cartridge tray (<NUM>). A vertical slot (<NUM>) is formed through part of staple cartridge (<NUM>) and opens upwardly through upper deck (<NUM>). One or more rows of staple apertures (<NUM>) are formed through upper deck (<NUM>) on one side of vertical slot (<NUM>), with one or more rows of staple apertures (<NUM>) being formed through upper deck (<NUM>) on the other side of vertical slot (<NUM>). End effector (<NUM>) is closed by distally advancing a closure tube (not shown) and a closure ring (<NUM>). Firing beam (<NUM>) is then advanced distally so that an upper pin of firing beam (<NUM>) enters longitudinal anvil slot (<NUM>). Simultaneously, a pusher block (<NUM>) located at the distal end of firing beam (<NUM>) engages a wedge sled (<NUM>) housed within cartridge body (<NUM>), such that wedge sled (<NUM>) is pushed distally by pusher block (<NUM>) as firing beam (<NUM>) is advanced distally through staple cartridge (<NUM>) and anvil (<NUM>).

During firing, cutting edge (<NUM>) of firing beam (<NUM>) enters vertical slot (<NUM>) toward distal end (<NUM>) of staple cartridge (<NUM>), severing tissue clamped between staple cartridge (<NUM>) and anvil (<NUM>). As best seen in <FIG>, wedge sled (<NUM>) presents inclined cam surfaces that urge staple drivers (<NUM>) upwardly as wedge sled (<NUM>) is driven distally through staple cartridge (<NUM>). A firing beam cap (<NUM>) slidably engages a lower surface of lower jaw (<NUM>). Wedge sled (<NUM>) is movable longitudinally within staple cartridge (<NUM>), while staple drivers (<NUM>) are movable vertically within staple cartridge (<NUM>). A middle pin (<NUM>) and pusher block (<NUM>) of firing beam (<NUM>) together actuate staple cartridge (<NUM>) by entering into vertical slot (<NUM>) within staple cartridge (<NUM>), driving wedge sled (<NUM>) distally into upward camming contact with staple drivers (<NUM>) that in turn drive staples (<NUM>) out through staple apertures (<NUM>) and into forming contact with staple forming pockets (<NUM>) on the inner surface of anvil (<NUM>). Additional examples of alternative surgical instruments and/or associated features are described in <CIT>.

It will be appreciated that any one or more of the teachings described below may be combined with any one or more of the teachings described above in connection with <FIG>.

In some examples of drive system (<NUM>) of surgical instrument (<NUM>) described above, it may be desirable to include certain bailout features to provide manual drive of drive system (<NUM>). For instance, during the course of a surgical procedure, unexpected operational conditions may sometimes be encountered. When such conditions are encountered, it may be desirable to immediately terminate or pause the surgical procedure, for example after a distal firing stroke of surgical instrument (<NUM>) has initiated. To do so, it may be desirable to actuate one or more potions of surgical instrument (<NUM>) manually or without input from robotic surgical system (<NUM>). One merely exemplary bailout feature may be a drive to retract an actuation assembly, shown as a driving assembly (<NUM>). This bailout feature may be desirable to return firing system components of surgical instrument (<NUM>) to a proximal, pre-fired position and enable jaws (<NUM>, <NUM>) of end effector (<NUM>) to be opened to release the clamped tissue and subsequently withdraw end effector (<NUM>) from a patient. This particular bailout feature may be referred to as a manual bailout mechanism in some examples.

In such manual bailout mechanisms, manual drive features may be integrated into robotically controlled drive features. Such a configuration may be desirable to promote a compact and light weight design. However, such integration may lead to a more complex mechanism, which may require more force during manual drive. As a result, it may be desirable to incorporate certain features into such manual bailout mechanisms to promote ease of use during manual operation.

<FIG> shows an exemplary bailout mechanism (<NUM>) (also referred to as bailout assembly, opening mechanism, or opening assembly) that may be readily incorporated into drive system (<NUM>) of surgical instrument (<NUM>) described above. Bailout mechanism (<NUM>) is generally configured to drive movement of jaws (<NUM>, <NUM>) of end effector (<NUM>) between an open and closed configuration using either motor driven input or manual input. Bailout mechanism (<NUM>) includes a motor input shaft (<NUM>) to facilitate motor input and a manual drive wheel (<NUM>) (also referred to as a knob, driver, or manual drive input) to facilitate manual input.

Motor input shaft (<NUM>) extends proximally from attachment interface (<NUM>). Although not shown, a distal end of motor input shaft (<NUM>) may include an input coupler similar to input couplers (<NUM>) described above. As with input couplers (<NUM>) described above, the input coupler may be configured to engage or otherwise communicate with a corresponding output coupler (not shown) of robotic arm (<NUM>) to rotate motor input shaft (<NUM>).

A proximal end of motor input shaft (<NUM>) includes an input gear (<NUM>). Input gear (<NUM>) is configured to mesh with a combination drive gear (<NUM>). As will be described in greater detail below, input gear (<NUM>) is generally configured to transmit rotary input provided by motor input shaft (<NUM>) to other components of bailout mechanism (<NUM>) to ultimately drive movement of jaws (<NUM>, <NUM>) of end effector (<NUM>).

Manual drive wheel (<NUM>) is generally configured for manual rotation by an operator. In the present example, manual drive wheel (<NUM>) extends from the proximal end of bailout mechanism (<NUM>) to permit actuation from the proximal end of surgical instrument (<NUM>). However, in other examples, manual drive wheel (<NUM>) may have a variety of alternative positions relative to surgical instrument (<NUM>). The shape of manual drive wheel (<NUM>) is generally cylindrical to promote grasping by an operator. To further promote gasping, manual drive wheel (<NUM>) may include one or more grasping features such as grooves, knurling, ribs, and/or etc..

A manual drive gear (<NUM>) extends distally from manual drive wheel (<NUM>). As will be described in greater detail below, manual drive gear (<NUM>) is generally configured to communicate a manual rotary input from manual drive wheel (<NUM>) to other portions of bailout mechanism (<NUM>) to ultimately drive movement of jaws (<NUM>, <NUM>) of end effector (<NUM>). In some examples, manual drive gear (<NUM>) may be integral with manual drive wheel (<NUM>) such that any rotatory motion of manual drive wheel (<NUM>) is communicated to manual drive gear (<NUM>). In other examples, manual drive wheel (<NUM>) and manual drive gear (<NUM>) may be connected by an intermediate mechanism to modify communication of at least some rotary input of manual drive wheel (<NUM>) to manual drive gear (<NUM>). By way of example only, one suitable intermediate mechanism may be a ratcheting mechanism to permit drive of manual drive gear (<NUM>) when manual drive wheel (<NUM>) is rotated in one direction, but prevent drive of manual drive gear (<NUM>) when manual drive wheel (<NUM>) is rotated in another direction. Of course, various alternative suitable intermediate mechanisms may be used as will be appreciated by those of ordinary skill in the art in view of the teachings herein.

Manual drive gear (<NUM>) is in communication with input gear (<NUM>). Thus, manual drive gear (<NUM>) is configured to transmit rotary motion to input gear (<NUM>) from manual drive wheel (<NUM>). Input gear (<NUM>), in turn, is in communication with a combination drive gear (<NUM>). Combination drive gear (<NUM>) is configured to drive an integral bevel gear (<NUM>), which communicates with a capstan gear (<NUM>). Capstan gear (<NUM>) defines a bevel complementary to the bevel of bevel gear (<NUM>) to promote meshing of the two gears (<NUM>, <NUM>). Capstan gear (<NUM>) is in communication with a capstan (<NUM>), which is configured to rotate with capstan gear (<NUM>) to manipulate actuation cables (<NUM>, <NUM>).

Capstan (<NUM>) defines a shaft extending from capstan gear (<NUM>) perpendicularly relative to a longitudinal axis defined by elongate shaft (<NUM>) of surgical instrument (<NUM>). Capstan (<NUM>) is configured as a double capstan and defines two spool channels (<NUM>, <NUM>) configured to receive actuation cables (<NUM>, <NUM>) in a helical pattern. In particular, capstan (<NUM>) defines a first spool channel (<NUM>) having a first pitch and a second spool channel (<NUM>) having a second pitch. In the present example, the first pitch and the second pitch are opposite of each other to promote an opposite threading for each actuation cable (<NUM>, <NUM>). As a consequence, rotation of capstan (<NUM>) in one direction may pull a portion of one actuation cable (<NUM>, <NUM>) toward capstan (<NUM>), while releasing a portion of another actuation cable (<NUM>, <NUM>) to move away from capstan (<NUM>).

Actuation cables (<NUM>, <NUM>) extend distally away from capstan (<NUM>) and into elongate shaft (<NUM>) of surgical instrument (<NUM>). In the present example, bailout mechanism (<NUM>) includes a retraction actuation cable (<NUM>) and an advancement actuation cable (<NUM>). As will be described in greater detail below, retraction actuation cable (<NUM>) and advancement actuation cable (<NUM>) are together configured to manipulate structures within elongate shaft (<NUM>) to control movement of end effector (<NUM>) using rotation of capstan (<NUM>) via motor input shaft (<NUM>) or manual drive wheel (<NUM>).

As best seen in <FIG> and <FIG>, bailout mechanism (<NUM>) further includes a shuttle (<NUM>), which may be disposed within elongate shaft (<NUM>) of surgical instrument (<NUM>). Shuttle (<NUM>) is generally configured to translate within elongate shaft (<NUM>) to drive movement of end effector (<NUM>). In particular, shuttle (<NUM>) includes an elongate frame (<NUM>) having a manipulation end (<NUM>) and a coupling end (<NUM>). Manipulation end (<NUM>) is in communication with pusher rod (<NUM>) to drive movement pusher member (<NUM>), which may be configured to manipulate lower jaw (<NUM>) relative to upper jaw (<NUM>). Thus, shuttle (<NUM>) is configured to manipulate jaws (<NUM>, <NUM>) by translating within elongate shaft (<NUM>) to push and pull push rod (<NUM>).

As noted above, movement of jaws (<NUM>, <NUM>) may be controlled by actuation cables (<NUM>, <NUM>). Thus, shuttle (<NUM>) of the present example is configured to engage actuation cables (<NUM>, <NUM>) to facilitate translation of shuttle (<NUM>) within elongate shaft (<NUM>) via actuation cables (<NUM>, <NUM>). Specifically, coupling end (<NUM>) of shuttle (<NUM>) is configured to couple to each end of actuation cable (<NUM>, <NUM>). As best seen in <FIG> and <FIG>, coupling end (<NUM>) includes a retraction receiver (<NUM>) and an advancement receiver (<NUM>). Retraction receiver (<NUM>) is configured to receive retraction actuation cable (<NUM>). Similarly, advancement receiver (<NUM>) is configured to receive advancement actuation cable (<NUM>).

Retraction receiver (<NUM>) and advancement receiver (<NUM>) are oriented in opposite directions to permit application of different force vectors to shuttle (<NUM>). For instance, retraction receiver (<NUM>) is oriented proximally to permit retraction actuation cable (<NUM>) to pull shuttle distally (<NUM>). Similarly, advancement receiver (<NUM>) is oriented distally to permit advancement actuation cable (<NUM>) to pull shuttle proximally with the assistance of other portions of shuttle (<NUM>) described in greater detail below.

Bailout mechanism (<NUM>) further includes a block (<NUM>) disposed within elongate frame (<NUM>) of shuttle (<NUM>). Block (<NUM>) includes a pully (<NUM>) configured to receive advancement actuation cable (<NUM>). Specifically, pully (<NUM>) is configured to reverse the direction of advancement actuation cable (<NUM>) such that advancement actuation cable (<NUM>) may pass through coupling end (<NUM>) of shuttle (<NUM>), reverse at pully (<NUM>), and then return to coupling end (<NUM>) to couple to advancement receiver (<NUM>). The configuration of pully (<NUM>) and coupling end (<NUM>) is generally desirable to permit advancement actuation cable (<NUM>) to pull shuttle (<NUM>) distally using tension provided by capstan (<NUM>).

Block (<NUM>) of the present example is not physically secured to shuttle (<NUM>). In other words, shuttle (<NUM>) may move relative to block (<NUM>). Although not shown, it should be understood that block (<NUM>) may be secured or otherwise mechanically grounded to elongate shaft (<NUM>). This configuration may be desirable to increase the mechanical advantage of advancement actuation cable (<NUM>) and pully (<NUM>). In other examples, block (<NUM>) may be secured directly to shuttle (<NUM>) to provide similar functionality without added mechanical advantage.

Returning to <FIG>, in an exemplary use, bailout mechanism (<NUM>) may receive input from either motor input shaft (<NUM>) or manual drive wheel (<NUM>). In both uses, this may result in turning of input gear (<NUM>) either by motor input shaft (<NUM>) directly or manual drive gear (<NUM>).

Rotation of input gear (<NUM>) by wither motor input shaft (<NUM>) or manual drive gear (<NUM>) may result in rotation of combination drive gear (<NUM>). Rotation of combination drive gear (<NUM>) rotates bevel gear (<NUM>), which rotates capstan gear (<NUM>). As a result of rotation of capstan gear (<NUM>), capstan (<NUM>) likewise rotates. One actuation cable (<NUM>, <NUM>) will then be tensioned and another actuation cable (<NUM>, <NUM>) will be relaxed, depending on the direction of rotation of capstan (<NUM>).

As shown in <FIG> and <FIG>, translation of shuttle (<NUM>) may be controlled by tensioning or relaxing a given actuation cable (<NUM>, <NUM>). For instance, if capstan (<NUM>) is rotated to tension retraction actuation cable (<NUM>), retraction actuation cable (<NUM>) will pull directly on coupling end (<NUM>) of shuttle (<NUM>) to translate shuttle (<NUM>) proximally. This proximal translation of shuttle (<NUM>) will pull pusher member (<NUM>) proximally and thereby open jaws (<NUM>, <NUM>).

Alternatively, if capstan (<NUM>) is rotated in an opposite direction to tension advancement actuation cable (<NUM>), the tension on advancement actuation cable (<NUM>) will be directed through pully (<NUM>) and then to coupling end (<NUM>) to pull shuttle (<NUM>) distally. This distal translation of shuttle (<NUM>) will push pusher member (<NUM>) distally and thereby close jaws (<NUM>, <NUM>).

<FIG> shows an exemplary alternative bailout mechanism (<NUM>) (also referred to as bailout assembly, opening mechanism, or opening assembly) that may be readily incorporated into drive system (<NUM>) of surgical instrument (<NUM>) described above. Bailout mechanism (<NUM>) is substantially similar to bailout mechanism (<NUM>) described above. For instance, like with bailout mechanism (<NUM>) described above, bailout mechanism (<NUM>) of the present example is generally configured to drive movement of jaws (<NUM>, <NUM>) of end effector (<NUM>) between an open and closed configuration using either motor driven input or manual input. As such, bailout mechanism (<NUM>) of the present example includes a motor input shaft (<NUM>) and a manual drive wheel (<NUM>) (also referred to as a knob, driver, or manual drive input) to facilitate manual input.

As with motor input shaft (<NUM>) described above, motor input shaft (<NUM>) of the present example extends proximally from attachment interface (<NUM>) and includes an input gear (<NUM>) similar to input gear (<NUM>) described above. Input gear (<NUM>) is configured to mesh with a combination drive gear (<NUM>) , which may be used to drive other components of bailout mechanism (<NUM>), as will be described in greater detail below.

Manual drive wheel (<NUM>) is substantially similar to manual drive wheel (<NUM>) described above in that manual drive wheel (<NUM>) is generally configured for manual rotation by an operator. Thus, the shape of manual drive wheel (<NUM>) is generally cylindrical to promote grasping by an operator. Also like manual drive wheel (<NUM>) described above, manual drive wheel (<NUM>) of the present example includes a manual drive gear (<NUM>) extending distally therefrom.

Capstan (<NUM>) of the present example is substantially similar to capstan (<NUM>) described above. For instance, capstan (<NUM>) defines a shaft extending from capstan gear (<NUM>) perpendicularly relative to a longitudinal axis defined by elongate shaft (<NUM>) of surgical instrument (<NUM>). Capstan (<NUM>) is configured as a double capstan and defines two spool channels (<NUM>, <NUM>) configured to receive actuation cables (<NUM>, <NUM>) in a helical pattern. As similarly described above, spool channels (<NUM>, <NUM>) include a first spool channel (<NUM>) having a first pitch and a second spool channel (<NUM>) having a second pitch. The first pitch and the second pitch are opposite of each other to promote an opposite threading for each actuation cable (<NUM>, <NUM>). As a consequence, rotation of capstan (<NUM>) in one direction may pull a portion of one actuation cable (<NUM>, <NUM>) toward capstan (<NUM>), while releasing a portion of another actuation cable (<NUM>, <NUM>) to move away from capstan (<NUM>).

Actuation cables (<NUM>, <NUM>) extend distally away from capstan (<NUM>) and into elongate shaft (<NUM>) of surgical instrument (<NUM>). In the present example, bailout mechanism (<NUM>) includes a retraction actuation cable (<NUM>) and an advancement actuation cable (<NUM>). As with retraction actuation cable (<NUM>) and advancement actuation cable (<NUM>) described above, retraction actuation cable (<NUM>) and advancement actuation cable (<NUM>) of the present example are together configured to manipulate structures within elongate shaft (<NUM>) to control movement of end effector (<NUM>) using rotation of capstan (<NUM>) via motor input shaft (<NUM>) or manual drive wheel (<NUM>).

Unlike retraction actuation cable (<NUM>) and advancement actuation cable (<NUM>) described above, retraction actuation cable (<NUM>) and advancement actuation cable (<NUM>) of the present example define differing diameters or thicknesses. In particular, retraction actuation cable (<NUM>) of the present example defines a diameter (Tr) that is greater than a diameter (Ta) defined by advancement actuation cable (<NUM>). This configuration may be desirable in some circumstances to promote the physical integrity of bailout mechanism (<NUM>). For instance, in some circumstances, a relatively large load may be applied to jaws (<NUM>, <NUM>) of end effector (<NUM>) by tissue, bone, or other structures proximate end effector (<NUM>). Such a load may resist movement of jaws (<NUM>, <NUM>) from a closed to open configuration. As a result, it may be beneficial for retraction actuation cable (<NUM>) to withstand relatively high loads to move jaws (<NUM>, <NUM>) from the closed configuration to the open configuration in such circumstances.

Although the present example promotes physical integrity of bailout mechanism (<NUM>) using an increased diameter of retraction actuation cable (<NUM>) relative to advancement actuation cable (<NUM>) (e.g., Tr > Ta), such benefits may be achieved by varying other physical properties of actuation cables (<NUM>, <NUM>). For instance, in some examples, retraction actuation cable (<NUM>) may be of a different material relative to advancement action cable (<NUM>) (e.g., INCONEL versus stainless steel). In other examples, actuation cables (<NUM>, <NUM>) may be of the same material but of a different configuration. For instance, in some examples, both actuation cables (<NUM>, <NUM>) may be braided, but retraction actuation cable (<NUM>) may have a higher strength braid relative to advancement actuation cable (<NUM>). In still other examples, various combinations of different physical properties may be used to promote physical integrity of bailout mechanism (<NUM>). In addition, or in the alternative, retraction actuation cable (<NUM>) may be independently manipulated in some examples such that retraction actuation cable (<NUM>) is configured as an independent direct pull cable.

As best seen in <FIG>, bailout mechanism (<NUM>) further includes a shuttle (<NUM>), which may be disposed within elongate shaft (<NUM>) of surgical instrument (<NUM>). Shuttle (<NUM>) is substantially similar to shuttle (<NUM>) described above. For instance, shuttle (<NUM>) of the present example generally configured to translate within elongate shaft (<NUM>) to drive movement of end effector (<NUM>). As with shuttle (<NUM>) described above, shuttle (<NUM>) of the present example includes an elongate frame (<NUM>) having a manipulation end (<NUM>) and a coupling end (<NUM>). Manipulation end (<NUM>) is in communication with pusher rod (<NUM>) such that shuttle (<NUM>) is configured to manipulate jaws (<NUM>, <NUM>) by translating within elongate shaft (<NUM>) to push and pull pusher rod (<NUM>).

Coupling end (<NUM>) of shuttle (<NUM>) is configured to couple to each end of actuation cable (<NUM>, <NUM>). As best seen in <FIG>, coupling end (<NUM>) includes a retraction receiver (<NUM>) and an advancement receiver (<NUM>). Retraction receiver (<NUM>) is configured to receive retraction actuation cable (<NUM>). Similarly, advancement receiver (<NUM>) is configured to receive advancement actuation cable (<NUM>). Although actuation cables (<NUM>, <NUM>) of the present example couple to coupling end (<NUM>) of shuttle (<NUM>), it should be understood that in some examples, one or more of actuation cables (<NUM>, <NUM>) may bypass shuttle (<NUM>) entirely and coupled directly to pusher member (<NUM>). For instance, in some examples, retraction actuation cable (<NUM>) may couple directly to pusher member (<NUM>) with retraction actuation cable (<NUM>) being configured to directly pull pusher member (<NUM>).

Unlike coupling end (<NUM>) described above, coupling end (<NUM>) of the present example includes a release feature (<NUM>) associated with advancement receiver (<NUM>). Release feature (<NUM>) of the present example is configured to couple advancement actuation cable (<NUM>) to coupling end (<NUM>) until a predetermined load is applied to advancement actuation cable (<NUM>), at which point release feature (<NUM>) is configured to release advancement actuation cable (<NUM>). In other words, release feature (<NUM>) is configured to operate as a mechanical fuse to release advancement actuation cable (<NUM>) from coupling end (<NUM>) upon the application of a load exceeding a predetermined threshold to advancement actuation cable (<NUM>). This configuration may be desirable to promote ease of use for bailout mechanism (<NUM>) during certain circumstances. For instance, when encountering some bailout conditions, relatively large force may be required to fully close jaws (<NUM>, <NUM>). In such circumstances, advancement actuation cable (<NUM>) may automatically release to prevent closure of jaws (<NUM>, <NUM>) beyond certain predetermined force limits. Meanwhile, retraction actuation cable (<NUM>) may remain attached to coupling end (<NUM>) to permit proximal translation of shuttle (<NUM>) for opening of jaws (<NUM>, <NUM>), while preventing distal translation of shuttle (<NUM>) for closure of jaws (<NUM>, <NUM>).

Release feature (<NUM>) of the present example includes a collar configured to release from advancement actuation cable (<NUM>) upon application of a predetermined load. The collar may be crimped or swaged to an end of advancement actuation cable (<NUM>) to promote fastening until the collar releases. Alternatively, some examples a portion of coupling end (<NUM>) may be configured to release advancement actuation cable (<NUM>). For instance, coupling end (<NUM>) may include a lug or other feature configured to release upon application of a predetermined load. In such examples, the collar may remain coupled to advancement actuation cable (<NUM>) upon release thereof.

Bailout mechanism (<NUM>) further includes a block (<NUM>) disposed within elongate frame (<NUM>) of shuttle (<NUM>). Block (<NUM>) of the present example is substantially similar to block (<NUM>) described above. For instance, like block (<NUM>), block (<NUM>) of the present example includes a pully (<NUM>) configured to receive advancement actuation cable (<NUM>) and reverse the direction of advancement actuation cable (<NUM>). Also like block (<NUM>) described above, block (<NUM>) of the present example may move relative to shuttle (<NUM>) and may be secured or otherwise mechanically grounded to elongate shaft (<NUM>). As noted above, this configuration may be desirable to increase the mechanical advantage of advancement actuation cable (<NUM>) and pully (<NUM>). In other examples, block (<NUM>) may be secured directly to shuttle (<NUM>) to provide similar functionality without added mechanical advantage.

It should be understood that block (<NUM>) and pully (<NUM>) in the present example is merely one example of a block and tackle mechanism that might be used to increase the mechanical advantage of either actuation cables (<NUM>, <NUM>). Thus, even though the present example includes one block (<NUM>) having one pully (<NUM>), it should be understood that in other examples, multiple blocks (<NUM>) with one pully (<NUM>), multiple blocks (<NUM>) with multiple pullies (<NUM>), or one block (<NUM>) with multiple pullies (<NUM>) may be used to increase the force applied by either actuation cable (<NUM>, <NUM>) or both. In merely one example, a similar block and tackle mechanism may be associated with retraction actuation cable (<NUM>). Such a block and tackle may define multiple synchronized loops of retraction actuation cable (<NUM>) to magnify the retraction force applied by retraction actuation cable (<NUM>). Of course, various other suitable configurations of block and tackle mechanisms will be apparent to those of ordinary skill in the art in view of the teachings herein.

As shown in <FIG>, in some examples, pusher member (<NUM>) may be coupled to push rod (<NUM>) using an axial strengthening feature (<NUM>). Axial strengthen feature (<NUM>) is generally configured to strengthen the interface between pusher member (<NUM>) and push rod (<NUM>) to resist separation between the two during relatively high axial loads (e.g., during proximal retraction of pusher member (<NUM>)). Axial strengthening feature (<NUM>) may take on a variety of forms suitable to withstand relatively high axially loads. For instance, in the present example, axial strengthening feature (<NUM>) include a mating keyed interface having a rounded key that may be received in a corresponding opening. In other examples, a threaded projection may be received in a threaded bore. In other examples, axial strengthening feature (<NUM>) may include a coupler. In still other examples, pusher member (<NUM>) and push rod (<NUM>) may instead be welded to each other. Of course, axial strengthening feature (<NUM>) of the present example is merely optional and may be omitted in some examples.

In use, bailout mechanism (<NUM>) of the present example functions similarly to bailout mechanism (<NUM>) described above. For instance, capstan (<NUM>) may be rotated in a first direction by either motor input shaft (<NUM>) or manual drive wheel (<NUM>) to tension advancement actuation cable (<NUM>) and simultaneously relax retraction actuation cable (<NUM>) for advancement of shuttle (<NUM>) distally and closure of jaws (<NUM>, <NUM>). Similarly, capstan (<NUM>) may be rotated in an opposite second direction by either motor input shaft (<NUM>) or manual drive wheel (<NUM>) to tension retraction actuation cable (<NUM>) and simultaneously relax advancement actuation cable (<NUM>) for retraction of shuttle (<NUM>) proximally and opening of jaws (<NUM>, <NUM>).

Unlike bailout mechanism (<NUM>) described above, the present use of bailout mechanism (<NUM>) may deviate upon an operator encountering unexpected operating conditions. For instance, in some circumstances external structures such as tissue, bone, other surgical instruments or equipment, and/or etc. may add additional forces to jaws (<NUM>, <NUM>) either preventing complete closure or resisting opening of jaws (<NUM>, <NUM>). In such circumstances, it may be beneficial to open jaws (<NUM>, <NUM>) to move or reposition surgical instrument (<NUM>). As described above, jaws (<NUM>, <NUM>) may be opened by retracting shuttle (<NUM>) proximally via rotation of capstan (<NUM>) to tension retraction actuation cable (<NUM>). Due to the diameter (Tr) of retraction actuation cable (<NUM>), retraction actuation cable (<NUM>) may be used to apply additional force to shuttle (<NUM>) and thus jaws (<NUM>, <NUM>).

Also during use, excessive application of force to advancement actuation cable (<NUM>) may result in release feature (<NUM>) releasing advancement actuation cable (<NUM>) from coupling end (<NUM>) of shuttle (<NUM>). As a result, distal translation of shuttle (<NUM>) may be disabled, thereby permitting only proximal translation of shuttle (<NUM>) via retraction actuation cable (<NUM>). In addition, releasing of advancement actuation cable (<NUM>) may release any tension applied to shuttle (<NUM>) in the distal direction opposite the force applied by retraction actuation cable (<NUM>), thereby reducing the force required for retraction actuation cable (<NUM>) to translate shuttle (<NUM>) proximally.

In some circumstances, a bailout mechanism similar to bailout mechanisms (<NUM>, <NUM>) described above may be operated manually by an operator using a manual input driver similar to manual drive wheels (<NUM>, <NUM>) described above. However, in some circumstances, a limiting factor on operation of such bailout mechanisms may be the ability to apply force to the manual input driver. Additionally, in some circumstances, another limiting factor may be the direction of the application of force to the manual input driver. Thus, it may be desirable to incorporate features into such manual input drivers to increase a user's ability to apply force or to ensure the force is applied in a particular direction.

<FIG> shows an exemplary alternative manual drive wheel (<NUM>) (also referred to as a knob, driver, or manual drive input), which may be readily incorporated into bailout mechanisms (<NUM>, <NUM>) described above. Manual drive wheel (<NUM>) is generally configured to enhance the ability of an operator to apply torque and/or power to manual drive wheel (<NUM>), thereby enhancing the ability to drive bailout mechanisms (<NUM>, <NUM>). Manual drive wheel (<NUM>) is similar to manual drive wheels (<NUM>, <NUM>) described above in that manual drive wheel (<NUM>) defines a generally cylindrical shape suitable for grasping and may additionally include one or more gripping features to enhance an operator's grip. Although not shown, it should be understood that manual drive wheel (<NUM>) may be in communication with one or more gears similar to manual drive gears (<NUM>, <NUM>) described above to transmit power from manual drive wheel (<NUM>) to other components of bailout mechanisms (<NUM>, <NUM>).

Unlike manual drive wheels (<NUM>, <NUM>) described above, manual drive wheel (<NUM>) of the present example includes an arm (<NUM>) (alternatively referred to as a lever) configured to extend and retract relative to a portion of manual drive wheel (<NUM>) to provide additional leverage for rotation of manual drive wheel (<NUM>). In particular, arm (<NUM>) is configured to pivot, flip or rotate from a retracted configuration shown in <FIG> to an extended configuration shown in <FIG>.

Arm (<NUM>) in the present example defines a length approximately corresponding to the diameter of manual drive wheel (<NUM>). Additionally, manual drive wheel (<NUM>) defines a channel (<NUM>) configured to receive arm (<NUM>). Channel (<NUM>) approximately corresponds to the thickness of arm (<NUM>) to permit arm (<NUM>) to be relatively flush with the top of manual drive wheel (<NUM>) when arm (<NUM>) is in the retracted configuration.

One side of arm (<NUM>) may be coupled to a portion of manual drive wheel (<NUM>) by a hinge, pivot shaft, living hinge, or other feature to promote pivoting, flipping or rotation of arm (<NUM>) relative to a portion of manual drive wheel (<NUM>). Meanwhile, an opposite end of arm (<NUM>) remains free for manipulation by an operator. This permits arm (<NUM>) to pivot about the coupling to increase the leverage provided by manual drive wheel (<NUM>) by <NUM> times or more. Although arm (<NUM>) of the present example is shown as using a pivoting, flipping or rotational action, it should be understood that other examples may include different configurations to provide extension of arm (<NUM>). For instance, in some examples, channel (<NUM>) may include a track or other feature to permit arm (<NUM>) to slide laterally out relative to a portion of manual drive wheel (<NUM>). Still other configurations for extension of arm (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

To enhance grip of arm (<NUM>) the exterior of arm (<NUM>) may optionally include one or more grip features. Such grip features may take on a variety of forms such as indentations, protrusions, knurling, and/or etc. Additionally, in some examples such grip features may match grip features incorporated into the perimeter of the cylindrical portion of manual drive wheel (<NUM>). In other examples, the grip features may be varied relative to those of manual drive wheel (<NUM>).

In use, arm (<NUM>) may initially be stowed in the retracted configuration as shown in <FIG>. In this configuration, manual drive wheel (<NUM>) may be used similar to manual drive wheels (<NUM>, <NUM>) described above. Specifically, an operator may grasp manual drive wheel (<NUM>) and rotate manual drive wheel (<NUM>) about an axis of rotation. Use of manual drive wheel (<NUM>) while arm (<NUM>) is in the retracted position may be desirable where limited force input is required or in circumstances where there is limited operational clearance between manual drive wheel (<NUM>) and other medical components or equipment.

In some contexts, it may be desirable to exert additional force on manual drive wheel (<NUM>). To assist with this, an operator may move arm (<NUM>) from the retracted configuration shown in <FIG> to the extended configuration shown in <FIG>. In the present example, arm (<NUM>) may be moved to the extended configuration by gasping the uncoupled end thereof and pivoting, flipping, or rotating arm (<NUM>) to the position shown in <FIG>. In this position, arm extends from the cylindrical perimeter of manual drive wheel (<NUM>) by about the diameter of manual drive wheel (<NUM>). Thus, an operator may rotate manual drive wheel (<NUM>) by applying a force to arm (<NUM>). Because of the length of arm (<NUM>), additional leverage is provided for increased torque.

Although not shown, in some examples, manual drive wheel (<NUM>) may be in communication with a ratcheting mechanism. In such examples, manual drive wheel (<NUM>) may be used either with arm (<NUM>) in the retracted configuration or the extended configuration to move repeatedly through a desired range of motion. In use, this repeated motion provided by such a ratcheting mechanism may be desirable to make it easier for an operator to apply force to manual drive wheel (<NUM>). This benefit may be especially present with arm (<NUM>) in the extended configuration, as it may permit an operator to avoid adjusting grip on arm (<NUM>) by not having to durn manual drive wheel (<NUM>) through a complete rotation.

<FIG> shows an exemplary alternative manual drive wheel (<NUM>) (alternatively referred to as a knob, driver, or manual drive input), which may be readily incorporated into bailout mechanisms (<NUM>, <NUM>) described above. Manual drive wheel (<NUM>) is generally configured to enhance the ability of an operator to apply torque and/or power to manual drive wheel (<NUM>), thereby enhancing the ability to drive bailout mechanisms (<NUM>, <NUM>). Manual drive wheel (<NUM>) is similar to manual drive wheels (<NUM>, <NUM>) described above in that manual drive wheel (<NUM>) defines a generally cylindrical shape suitable for grasping and may additionally include one or more gripping features to enhance an operator's grip. Although not shown, it should be understood that manual drive wheel (<NUM>) may be in communication with one or more gears similar to manual drive gears (<NUM>, <NUM>) described above to transmit power from manual drive wheel (<NUM>) to other components of bailout mechanisms (<NUM>, <NUM>).

Unlike manual drive wheels (<NUM>, <NUM>) described above, manual drive wheel (<NUM>) of the present example includes an instrument retaining feature (<NUM>). Instrument retaining feature (<NUM>) is generally configured to promote application of force to manual drive wheel (<NUM>) along a specific axis to promote engagement between surgical instrument (<NUM>) and robotic arm (<NUM>) at chassis (<NUM>) of surgical instrument (<NUM>). As best seen in <FIG> and <FIG>, instrument retaining feature (<NUM>) includes a drive lock (<NUM>), a resilient feature (<NUM>), and a wheel lock (<NUM>). Drive lock (<NUM>) of the present example defines an irregular configuration similar to a castle nut. As will be described in greater detail below, the configuration of drive lock (<NUM>) may be complementary to the configuration of wheel lock (<NUM>) to promote releasable engagement between drive lock (<NUM>) and wheel lock (<NUM>). Although not shown, it should be understood that drive lock (<NUM>) may be in communication with other components of bailout mechanisms (<NUM>, <NUM>) to transmit rotary motion from manual drive wheel (<NUM>) to other drive components of bailout mechanisms (<NUM>, <NUM>).

Wheel lock (<NUM>) is best seen in <FIG>. As can be seen, wheel lock (<NUM>) extends from an underside surface of manual drive wheel (<NUM>). In this configuration, wheel lock (<NUM>) is configured to selectively engage drive lock (<NUM>) when manual drive wheel (<NUM>) is coupled to the rest of surgical instrument (<NUM>). The particular configuration of wheel lock (<NUM>) is complementary to the particular configuration of drive lock (<NUM>). For instance, as noted above, drive lock (<NUM>) includes a configuration similar to a castle nut. Thus, wheel lock (<NUM>) of the present example likewise includes a configuration similar to a castle nut, but with an opposite pattern to promote mating engagement between drive lock (<NUM>) and wheel lock (<NUM>).

Although drive lock (<NUM>) and wheel lock (<NUM>) of the present example use a configuration similar to a castle nut, it should be understood that in other examples various alternative configurations may be used. For instance, the configuration used in the present example provides a paw or cam surface that may be used to selectively transfer rotary motion from wheel lock (<NUM>) to drive lock (<NUM>). Thus, any other suitable mating surface may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein.

Returning to <FIG>, resilient feature (<NUM>) is disposed between drive lock (<NUM>) and wheel lock (<NUM>). Resilient feature (<NUM>) is generally configured to bias wheel lock (<NUM>) away from drive lock (<NUM>) such that drive lock (<NUM>) and wheel lock (<NUM>) may not be matingly engaged unless a suitable force is applied to manual drive wheel (<NUM>). Resilient feature (<NUM>) of the present example is configured as a coil spring, although in other examples various alternative configurations may be used such as torsion springs, rubber or polymer cylinders, and/or etc..

In use, manual drive wheel (<NUM>) may be initially in a disengaged configuration as shown in <FIG>. In this configuration, resilient feature (<NUM>) biases manual drive wheel (<NUM>) proximally from surgical instrument (<NUM>) such that wheel lock (<NUM>) is disengaged from drive lock (<NUM>). With wheel lock (<NUM>) disengaged from drive lock (<NUM>), manual drive wheel (<NUM>) may rotate freely without transmitting rotation to any other portion of bailout mechanism (<NUM>, <NUM>).

To initiate drive of bailout mechanism (<NUM>, <NUM>), a distal force may be applied to manual drive wheel (<NUM>) as shown in <FIG>. This force may overcome the force of resilient feature (<NUM>) and drive manual drive wheel (<NUM>) distally to engage wheel lock (<NUM>) with drive lock (<NUM>). Manual drive wheel (<NUM>) may then be rotated. During rotation, rotation of manual drive wheel (<NUM>) is communicated to other components of bailout mechanism (<NUM>, <NUM>) via engagement between wheel lock (<NUM>) and drive lock (<NUM>).

As manual drive wheel (<NUM>) is rotated, distal force sufficient to overcome the resilient bias of resilient feature (<NUM>) may be maintained to maintain engagement between wheel lock (<NUM>) and drive lock (<NUM>). This distal force component may be desirable to force surgical instrument (<NUM>) distally toward robotic arm (<NUM>) to promote engagement between surgical instrument (<NUM>) and robotic arm (<NUM>). Without such a distal force component, an operator might apply excessive force to manual drive wheel (<NUM>) leading to disengagement of surgical instrument (<NUM>) from robotic arm (<NUM>). Thus, manual drive wheel (<NUM>) of the present example is desirable to prevent inadvertent disengagement between surgical instrument (<NUM>) and robotic arm (<NUM>).

Any one or more of the teachings, expressions, embodiments, examples, etc. described herein may be combined with any one or more of the teachings, expressions, embodiments, examples, etc. described in U. Ref. No. END9348USNP1], entitled "Methods of Operating a Robotic Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP2], entitled "Multi-Threshold Motor Control Algorithm for Powered Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP3], entitled "Variable Response Motor Control Algorithm for Powered Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP4], entitled "Powered Surgical Stapler Having Independently Operable Closure and Firing Systems," filed on even date herewith; U. Ref. No. END9348USNP5], entitled "Firing System Features for Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP6], entitled "Multiple-Sensor Firing Lockout Mechanism for Powered Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP7], entitled "Proximally Located Firing Lockout Mechanism for Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP8], entitled "Cartridge-Based Firing Lockout Mechanism for Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP9], entitled "Sled Restraining Member for Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP10], entitled "Firing Member Tracking Feature for Surgical Stapler," filed on even date herewith; U. Ref. No. END9348USNP11], entitled "Adjustable Power Transmission Mechanism for Powered Surgical Stapler," filed on even date herewith; and/or U. Ref. No. END9348USNP13], entitled "Deflectable Firing Member for Surgical Stapler," filed on even date herewith.

Versions described above may be designed to be disposed of after a single use, or they can be designed to be used multiple times. Reconditioning may include any combination of the steps of disassembly of the systems, instruments, and/or portions thereof, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, some versions of the systems, instruments, and/or portions thereof may be disassembled, and any number of the particular pieces or parts of the systems, instruments, and/or portions thereof may be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, some versions of the systems, instruments, and/or portions thereof may be reassembled for subsequent use either at a reconditioning facility, or by an operator immediately prior to a procedure. Those skilled in the art will appreciate that reconditioning of systems, instruments, and/or portions thereof may utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned systems, instruments, and/or portions thereof, are all within the scope of the present application.

In one sterilization technique, the systems, instruments, and/or portions thereof is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and system, instrument, and/or portion thereof may then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation may kill bacteria on the system, instrument, and/or portion thereof and in the container. The sterilized systems, instruments, and/or portions thereof may then be stored in the sterile container for later use. Systems, instruments, and/or portions thereof may also be sterilized using any other technique known in the art, including but not limited to beta or gamma radiation, ethylene oxide, or steam.

Claim 1:
A surgical instrument (<NUM>), comprising:
(a) a body;
(b) a shaft assembly (<NUM>) extending distally from the body;
(c) an end effector (<NUM>) disposed on a distal end of the shaft assembly (<NUM>), wherein the end effector (<NUM>) includes a first jaw and a second jaw (<NUM>, <NUM>);
(d) an actuation assembly including a pusher member (<NUM>) configured to move relative to the end effector (<NUM>) to drive movement of the first jaw, the second jaw, or both the first jaw and the second jaw (<NUM>, <NUM>); and
(e) a bailout mechanism (<NUM>) including a first elongate actuation element (<NUM>) and a second elongate actuation element (<NUM>), wherein a portion of the bailout mechanism (<NUM>) is configured to selectively apply tension to the first elongate actuation element (<NUM>) and the second elongate actuation element (<NUM>) to move the pusher member (<NUM>), characterised in that the first elongate actuation element (<NUM>) is stronger in tension than the second elongate actuation element (<NUM>).