Patent Description:
Surgical devices for stapling tissue are well known in the art and typically include a handle assembly, a body portion extending distally from the handle assembly, and a tool assembly supported on a distal end of the body portion. The tool assembly includes first and second jaws which are movable in relation to each other between open and clamped or approximated positions. The first jaw includes an anvil assembly and the second jaw supports a staple cartridge which houses a plurality of staples.

In known surgical stapling devices, a clamping member engages the first and second jaws to move the first and second jaws from the open position to the clamped position and is movable along the first and second jaws to advance an actuation sled to sequentially eject staples from the staple cartridge. In the absence of a staple cartridge, or in the presence of a spent staple cartridge, i.e., if the actuation sled is missing, or in an advanced position, advancement of the clamping member will cause cutting of tissue without stapling tissue, resulting in complications. <CIT> relates to a stapling device that includes a flexible lockout member wherein movement of the actuation sled of the cartridge assembly causes the lockout member to move to a flexed condition to allow advancement of a drive assembly.

A continuing need exists in the art for a surgical stapling device with a lockout mechanism for preventing undesired advancement of the drive assembly when the actuating sled or staple cartridge is not present and when the staple cartridge is spent.

A first aspect of the present invention provides a tool assembly as claimed in claim <NUM> annexed hereto. The tool assembly includes a cartridge assembly and an anvil assembly pivotally secured to the cartridge assembly such that the tool assembly is movable between open and clamped positions. The cartridge assembly includes a channel member, a staple cartridge supported in the channel member, and an actuation sled positioned within the staple cartridge. The actuation sled is movable from a first position to a second position to eject staples from the staple cartridge. The tool assembly further includes a drive assembly having a clamping member movable from an initial position to an advanced position to move the actuation sled from the first position to the second position, and a lockout member secured to the channel member and moveable between a relaxed condition and a flexed condition. Movement of the actuation sled from the first position towards the second position causes the lockout member to move to the flexed condition to permit advancement of the drive assembly.

The lockout member is configured to prevent advancement of the drive assembly when the actuation sled is missing, or in the second position. The actuation sled includes a ramp feature positioned to engage the lockout member as the actuation sled moves from the first position towards the second position. The lockout member may include an interlock spring secured to the channel member. The interlock spring may include a blocking portion that is located in a first position adjacent the channel member when the locking mechanism is in the relaxed condition and in a second position spaced from the channel member when the locking mechanism is in the flexed condition. The interlock spring may be welded to the channel member. The interlock spring may include an engagement portion extending distally from the blocking portion of the interlock spring.

In other aspects of the disclosure, the clamping member includes a vertical strut, an upper beam, and a lower beam. The vertical strut may include a knife. The clamping member may include a retraction ramp that is engaged by the engagement portion of the interlock spring when the drive assembly moves from the advanced position back to the initial position. Engagement of the engagement portion of the interlock spring by the retraction ramp of the clamping member may cause the interlock spring to move from the relaxed condition to the flexed condition.

In aspects of this disclosure, the tool assembly forms part of a surgical stapling device comprising an elongate body portion and the tool assembly pivotally secured to the elongate body portion. The tool assembly includes a cartridge assembly and an anvil assembly pivotally secured to the cartridge assembly and movable in relation to the cartridge assembly between open and clamped positions. The cartridge assembly includes a channel member, a staple cartridge supported in the channel member, and an actuation sled positioned within the staple cartridge. The actuation sled is movable from a first position to a second position to eject staples from the staple cartridge. The tool assembly further includes a drive assembly having a clamping member movable from an initial position to an advanced position to move the actuation sled from the first position to the second position, and a lockout member secured to the channel member and moveable between a relaxed condition and a flexed condition. Movement of the actuation sled from the first position towards the second position causes the lockout member to move from the relaxed condition to the flexed condition to permit advancement of the drive assembly.

Various aspects of the disclosure are described herein with reference to the drawings, wherein:.

The disclosed surgical stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that the aspects of the disclosure are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure. In addition, directional terms such as front, rear, upper, lower, top, bottom, distal, proximal, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

In this description, the term "proximal" is used generally to refer to that portion of the device that is closer to a clinician, while the term "distal" is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term "clinician" is used generally to refer to medical personnel including doctors, nurses, and support personnel.

The disclosed surgical stapling device includes a lockout mechanism for preventing advancement of a drive assembly in the absence of an actuating sled, cartridge assembly and/or in the presence of a previously fired or defective cartridge assembly.

<FIG> illustrates a surgical stapling device according to exemplary aspects of the disclosure shown generally as stapling device <NUM>. The stapling device <NUM> includes a powered handle assembly <NUM>, an adapter assembly <NUM> releasably secured to the powered handle assembly <NUM>, and a loading unit <NUM> releasably secured to the adapter assembly <NUM>. The handle assembly <NUM> include a stationary grip <NUM> that supports actuation buttons 24a, 24b for controlling operation of various functions of the stapling device <NUM> including clamping and cutting of tissue. Although shown as individual or separable components, it is envisioned that any or all of the powered handle assembly <NUM>, adapter assembly <NUM>, and loading unit <NUM> may be integrally formed.

The stapling device <NUM> is illustrated as an electrically powered stapling device including an electrically powered handle assembly that may support one or more batteries (not shown). Examples of electrically powered stapling devices can be found in <CIT> and <CIT>. Alternately, it is envisioned that the loading unit <NUM> could also be incorporated into a manual stapling device such as disclosed in <CIT> or a stapling device that is configured for use with a robotic system such as disclosed in <CIT> that does not include a handle assembly.

<FIG> illustrates the loading unit <NUM> of the stapling device <NUM> (<FIG>) including a body portion <NUM> and a tool assembly <NUM> pivotally secured to the body portion <NUM>. A proximal end of the body portion <NUM> is configured for releasable engagement with the adapter assembly <NUM> (<FIG>).

<FIG> illustrates the tool assembly <NUM> of the loading unit <NUM> including a jaw assembly <NUM> having an anvil assembly <NUM> and a cartridge assembly <NUM>. The cartridge assembly <NUM> includes a staple cartridge 116a and a channel member <NUM> configured to receive the staple cartridge 116a. In certain aspects of the disclosure, and as shown, the staple cartridge 116a may be replaceable. The anvil assembly <NUM> and cartridge assembly <NUM> are pivotable relative to each other between an open position (<FIG>) and an approximated or clamped position (<FIG>). The anvil assembly <NUM> and the cartridge assembly <NUM> may be biased to the open position by one or more springs, e.g., leaf springs <NUM>. The loading unit <NUM> is substantially as described in <CIT> ("the '<NUM> patent"). Accordingly, the components of the loading unit <NUM> which are common to that which is disclosed in the '<NUM> patent will only be described herein to the extent necessary to fully disclose the aspects of the lockout mechanism <NUM> and its method of operation.

A drive assembly <NUM> extends through and from the body portion <NUM> (<FIG>) of the loading unit <NUM> into the tool assembly <NUM>. The drive assembly <NUM> includes a dynamic clamping member <NUM> and a drive beam <NUM> extending proximally from the dynamic clamping member <NUM> into the body portion <NUM> of the loading unit <NUM>. In certain aspects of the disclosure, the drive beam <NUM> of the drive assembly <NUM> is formed from a plurality of stacked sheets that are formed of a resilient or flexible material, e.g., stainless steel. A proximal end of the drive beam <NUM> is configured to engage a drive member (not shown) of the adapter assembly <NUM> (<FIG>) and/or the powered handle assembly <NUM> (<FIG>) for advancing and retracting the drive assembly <NUM> within the body portion <NUM> and the tool assembly <NUM>.

The anvil assembly <NUM> of the jaw assembly <NUM> of the tool assembly <NUM> defines a longitudinal slot <NUM> (<FIG>) and an inner clamping surface 114a on either side of the longitudinal slot <NUM>. In certain aspects of the disclosure, the anvil assembly <NUM> includes an anvil body <NUM> and an anvil plate <NUM> (<FIG>) secured to the underside of the anvil body <NUM> to form the longitudinal slot <NUM>. The anvil plate <NUM> defines a plurality of staple receiving depressions (not shown).

The channel member <NUM> of the cartridge assembly <NUM> is pivotally secured to the anvil assembly <NUM>. The channel member <NUM> defines a channel <NUM> that receives the cartridge assembly <NUM>. The staple cartridge 116a of the cartridge assembly <NUM> of the jaw assembly <NUM> includes a cartridge body <NUM> supported in a cartridge holder <NUM>, a plurality of staples "S", and a staple firing assembly <NUM>. The cartridge body <NUM> of the staple cartridge 116a is secured within the channel <NUM> of the channel member <NUM> with, e.g., a snap-fit connection. Other forms of connections are contemplated and may be used in place of the snap-fit connection, or in addition thereto, to fixedly or releasably secure the staple cartridge 116a within the channel <NUM> of the channel member <NUM>. The channel member <NUM> further defines a longitudinal slot <NUM> and a clamping surface 118a on either side of the longitudinal slot <NUM>.

The cartridge body <NUM> of the staple cartridge 116a defines a plurality of laterally spaced staple retention slots <NUM> which are positioned in alignment with the staple receiving depressions (not shown) in the anvil plate <NUM> (<FIG>) of the anvil assembly <NUM> when the tool assembly is in the clamped position. Each retention slot <NUM> receives a fastener or staple "S" and a pusher <NUM>. The staple firing assembly <NUM> includes an actuation sled <NUM> (<FIG>) and a plurality of pusher members <NUM>. The actuation sled <NUM> is positioned within the cartridge body <NUM> of the staple cartridge 116a and is configured to pass longitudinally through the cartridge body <NUM> into engagement with the pushers <NUM> to lift the pushers within the cartridge body <NUM> to sequentially eject the staples "S" from the cartridge body <NUM>.

<FIG> illustrate the actuation sled <NUM> of the staple firing assembly <NUM> which includes a base portion <NUM>, a central rib portion <NUM> extending upwardly from the base portion <NUM>, and first and second paired camming rib portions 174a, 174b. A ramp feature <NUM> extends downwardly from the base portion <NUM> and includes an angled surface 176a. The angle surface 176a faces distally, i.e., away from the drive assembly <NUM>. The ramp feature <NUM> may include a stop surface (not shown) for engaging a hard stop 118b (<FIG>) of the channel member <NUM>.

<FIG> illustrates an interlock spring <NUM> of the lockout mechanism <NUM>. The interlock spring <NUM> includes a pair of tang portions <NUM>, an elongate body or spring portion <NUM> extending from the each of tang portions <NUM>, and a blocking portion <NUM> extending between the elongate body portions <NUM>. The tang portions <NUM> of the interlock spring <NUM> are spaced apart from one another to define a channel <NUM> through which the dynamic clamping member <NUM> (<FIG>) of the drive assembly <NUM> (<FIG>) may pass. An engagement portion <NUM> extends distally from the blocking portion <NUM>. The blocking portion <NUM> of the interlock spring <NUM> defines a notch or camming feature <NUM>.

<FIG> and <FIG> illustrate placement of the interlock spring <NUM> of the lockout mechanism <NUM> on the channel member <NUM> of the cartridge assembly <NUM> of the loading unit <NUM>. The channel member <NUM> defines a cutout <NUM> for receiving the interlock spring <NUM>. The cutout <NUM> is formed on an underside of a proximal portion of the channel member <NUM>. Each of the tang portions <NUM> is secured to the channel member <NUM> on either side of the longitudinal slot <NUM>. In certain aspects of the disclosure, the tang portions <NUM> are welded to the channel member <NUM>. Alternatively, the tang portions <NUM> may be secured to the channel member <NUM> in any suitable manner, including, with adhesives, mechanical fasteners, or friction fit. The interlock spring <NUM> is positioned on the channel member <NUM> such that the elongate body portions <NUM> of the interlock spring <NUM> extend distally along the channel member <NUM> on opposite sides of the longitudinal slot <NUM>. When the interlock spring <NUM> is secured to the channel member <NUM>, the blocking portion <NUM> of the interlock spring <NUM> extends across the longitudinal slot <NUM> such that the notch or camming feature <NUM> is centered in the blocking portion <NUM> of the locking spring <NUM> and is aligned with the longitudinal slot <NUM> and the engagement portion extends along the longitudinal slot <NUM>. With only the tang portions <NUM> of the interlock spring <NUM> secured to the channel member <NUM>, the elongate body portions <NUM> of the interlock spring <NUM> are able to flex outwardly away from the channel member <NUM>.

<FIG> illustrate the dynamic clamping member <NUM> of the drive assembly <NUM> which includes an upper flange portion <NUM>, a lower flange portion <NUM>, and a vertical strut <NUM> interconnecting the upper flange portion <NUM> and the lower flange portion <NUM>. The upper flange portion <NUM> is sized and dimensioned to be slidably received within the longitudinal slot <NUM> (<FIG>) of the anvil assembly <NUM> and includes a clamping surface 132a (<FIG>) that engages the inner clamping surface 114a (<FIG>) of the anvil assembly <NUM> to cause the pivoting of the anvil assembly <NUM> relative to the cartridge assembly <NUM> to move the tool assembly <NUM> from the open position to the clamped position. The lower flange portion <NUM> is sized and dimensioned to be slidably received along an outer surface of the channel member <NUM> (<FIG>) and includes clamping surfaces 134a (<FIG>) facing the upper flange portion <NUM> of the dynamic clamping member <NUM>. The vertical strut <NUM> of the dynamic clamping member <NUM> is received within the longitudinal slot <NUM> of the channel member <NUM> and includes a knife 136a.

The dynamic clamping member <NUM> of the drive assembly <NUM> defines a retraction ramp <NUM> (<FIG>) on a proximal portion of the lower flange portion <NUM>. The retraction ramp <NUM> is positioned to be aligned with the engagement portion <NUM> (<FIG>) of the interlock spring <NUM>. The lower flange portion <NUM> of the dynamic clamping member <NUM> includes a lead-in surface <NUM> (<FIG>) and the upper flange portion <NUM> of the dynamic clamping member <NUM> includes a lead-in surface <NUM> (<FIG>). As will be described in further detail below, the lead-in surface <NUM> of the lower flange portion <NUM> includes an angled surface 137a and a blocking surface 137b, and the lead-in surface <NUM> of the upper flange portion <NUM> includes a blocking surface 139a.

<FIG> illustrate the loading unit <NUM> of the stapling device <NUM> (<FIG>) including the staple cartridge 116a in a pre-fired condition and the drive assembly <NUM> in a retracted position. In the pre-fired condition, the actuation sled <NUM> of the cartridge assembly <NUM> is in an initial position in which the ramp feature <NUM> of the actuation sled <NUM> is positioned proximal of the blocking portion <NUM> of the interlock spring <NUM>, resulting in the interlock spring <NUM> being in an unflexed condition. When the drive assembly <NUM> is in the retracted position, the dynamic clamping member <NUM> of the drive assembly <NUM> is longitudinally spaced from the cartridge assembly <NUM> of the jaw assembly <NUM>. Springs <NUM> bias the anvil assembly <NUM> and the cartridge assembly <NUM> to the open position to permit placement of tissue between tissue contacting surfaces 114b (<FIG>), 116b of the respective anvil assembly <NUM> and cartridge assembly <NUM>. In the retracted position, the dynamic clamping member <NUM> of the drive assembly <NUM> is also longitudinally spaced from the actuation sled <NUM>.

<FIG> and <FIG> illustrate the drive assembly <NUM> of the loading unit <NUM> in a first partially advanced position. Movement of the drive assembly <NUM> to the first partially advanced position, as indicated by arrow "A" in <FIG>, pivots the jaw assembly <NUM> to the clamped position, as indicated by arrow "B" in <FIG>. More particularly, the upper flange portion <NUM> of the dynamic clamping member <NUM> engages the clamping surface 114a of the anvil assembly <NUM> and the lower flange portion <NUM> of the dynamic clamping member <NUM> engages the clamping surface 118a of the channel member <NUM> to pivot the channel member <NUM>, including the staple cartridge 116a, to the clamped position. In the first partially advanced position, the dynamic clamping member <NUM> of the drive assembly <NUM> may be, as shown, longitudinally spaced from the actuation sled <NUM> to prevent any unintended advancement of the actuation sled <NUM> during closing of the jaw assembly <NUM>.

<FIG> illustrates the drive assembly <NUM> of the loading unit <NUM> in a second partially advanced position. Movement of the drive assembly <NUM> to the second partially advanced position, as indicated by arrows "C", causes the dynamic clamping member <NUM> to engage the actuation sled <NUM> to cause advancement of the actuation sled <NUM>. Advancement of the actuation sled <NUM> causes the ramp feature <NUM> of the actuation sled <NUM> to engage the blocking portion <NUM> of the interlock spring <NUM> at the notch or camming feature <NUM>.

<FIG> and <FIG> illustrate continued advancement of the drive assembly <NUM> of the loading unit <NUM>, as indicated by arrows "D", to a third partially advanced position. The continued advancement of the drive assembly <NUM> to the third partially advanced position causes the continued advancement of the actuation sled <NUM> in relation to the interlock spring <NUM>. As the actuation sled <NUM> moves distally in relation to the interlock spring <NUM>, the ramp feature <NUM> of the actuation sled <NUM> moves beneath the blocking portion <NUM> to flex the elongate portions of the interlock spring <NUM> such that the blocking portion <NUM> of the interlock spring <NUM> lifts in the direction of arrow "E" in <FIG> over the ramp feature <NUM> and position the blocking portion <NUM> onto the angled surface 137a of the lead-in surface <NUM> of the lower flange portion <NUM> of the dynamic clamping member <NUM>. As the blocking portion <NUM> of the interlock spring <NUM> flexes away from the channel member <NUM>, the lower flange portion <NUM> of the dynamic clamping member <NUM> can clear the blocking portion <NUM>, thereby permitting continued advancement of the drive assembly <NUM>.

<FIG> and <FIG> illustrate the jaw assembly <NUM> of the loading unit <NUM> following an actuation stroke of the stapling device <NUM> (<FIG>). The actuation sled <NUM> of cartridge assembly <NUM> is in its distal-most position following the actuation stroke of the loading unit <NUM> and remains in the distal-most position during retraction of the drive assembly <NUM>. The drive assembly <NUM> is retracted, as indicated by arrow "F" in <FIG>, to a first retracted position wherein the dynamic clamping member <NUM> engages the interlock spring <NUM>. More particularly, the engagement portion <NUM> of the interlock spring <NUM> engages the lower flange portion <NUM> at the retraction ramp <NUM>. Engagement of the engagement portion <NUM> of the interlock spring <NUM> with the retraction ramp <NUM> causes the blocking portion <NUM> of the interlock spring <NUM> to flex away from the channel portion <NUM>, as indicated by arrow "G" in <FIG>, such that the lower flange portion <NUM> of the dynamic clamping member <NUM> can pass over and clear the blocking portion <NUM>, thereby permitting continued retraction of the drive assembly.

<FIG> illustrates the continued retraction of the drive assembly <NUM>. More particularly, once the blocking portion <NUM> of the interlock spring <NUM> passes the retraction ramp <NUM> of the dynamic clamping member <NUM>, the blocking portion <NUM> of the interlock spring <NUM> remains in engagement with an outer surface of the lower flange portion <NUM> of the dynamic clamping member <NUM> to permit the dynamic clamping member <NUM> to pass by the blocking portion <NUM> of the interlock spring <NUM>, permitting continued retraction of the drive assembly <NUM> to a position in which lower beam <NUM> of the dynamic clamping member <NUM> is positioned proximally of the blocking portion <NUM>.

<FIG> illustrates the drive assembly <NUM> in a locked position. Following a stapling procedure, the drive assembly <NUM> is retracted to a point in which the lower beam <NUM> is positioned proximally of the blocking portion <NUM> of the interlock spring <NUM>. Once the lower beam <NUM> is positioned proximally of the blocking portion <NUM> of the interlock spring <NUM>, the drive assembly <NUM> is prevented from being readvanced. More particularly, in the absence of the actuation sled <NUM> (<FIG>), i.e., without the flexing of the interlock spring <NUM> caused by the ramp feature <NUM> of the actuation sled <NUM>, the blocking portion <NUM> of the interlock spring <NUM> engages the blocking surface 137b of the lead-in surface <NUM> of the lower flange portion <NUM> of the dynamic clamping member <NUM>. Engagement of the blocking surface 137b of the lower flange portion <NUM> of the dynamic clamping member <NUM> prevents continued advancement of the drive assembly <NUM> past the blocking portion <NUM> of the interlock spring <NUM>.

<FIG> illustrates the drive assembly <NUM> within the jaw assembly <NUM> of the loading unit <NUM> in an inverted or upside-down condition. The drive assembly <NUM> is in the inverted condition as a result of a manufacturing error in which the dynamic clamping member <NUM> is positioned one hundred-eighty degrees (<NUM>°) from its correct position. In this manner, the knife 136a is not aligned with the gap defined between the tissue contacting surfaces 114b (<FIG>), 116b of the anvil and cartridge assemblies <NUM>, <NUM>, respectively. Firing of the loading unit <NUM> when the drive assembly <NUM> is in the inverted position may cause significant damage to tissue being stapled (not shown) as the knife 136a of the dynamic clamping member <NUM> is not in proper alignment with the jaw assembly <NUM>.

<FIG> illustrates partial advancement of the drive assembly <NUM>, as indicated by arrow "H", when the drive assembly <NUM> is in the inverted condition. The partial advancement of the drive assembly <NUM> causes advancement of the actuation sled <NUM> which cause partial flexing of the interlock spring <NUM>, as indicated by arrow "I". However, since the dynamic clamping member <NUM> is inverted, the blocking portion <NUM> of the interlock spring <NUM> engages the blocking surface 139a of the lead-in surface <NUM> of the upper flange portion <NUM> of the dynamic clamping member <NUM> instead of the angled surface 137a of the lead-in surface <NUM> of the lower flange portion <NUM> of the dynamic clamping member <NUM>. In this manner, even in the presence of the actuation sled <NUM>, the interlock spring <NUM> prevents further advancement of the drive assembly <NUM> when the dynamic clamping member <NUM> of the drive assembly is improperly installed in the stapling device <NUM>.

Claim 1:
A tool assembly (<NUM>) comprising:
a cartridge assembly (<NUM>) including a channel member (<NUM>), a staple cartridge (116a) supported in the channel member, and an actuation sled (<NUM>) positioned within the staple cartridge, the actuation sled being movable from a first position to a second position to eject staples ("S") from the staple cartridge;
an anvil assembly (<NUM>) pivotally secured to the cartridge assembly (<NUM>) and movable in relation to the cartridge assembly between open and clamped positions;
a drive assembly (<NUM>) including a clamping member (<NUM>) movable from an initial position to an advanced position to move the actuation sled (<NUM>) from the first position to the second position; and
a lockout member (<NUM>) secured to the channel member (<NUM>) and moveable between relaxed and flexed conditions, wherein movement of the actuation sled (<NUM>) from the first position towards the second position causes the lockout member to move from the relaxed condition to the flexed condition to permit advancement of the drive assembly, characterized in that the actuation sled (<NUM>) includes a ramp feature (<NUM>) positioned to engage the lockout member as the actuation sled moves from the first position towards the second position.