BACKGROUND

Technical Field

The present disclosure relates generally to surgical loading units for endoscopic use and, more specifically, to surgical loading units having articulation assemblies for articulating an end effector of the surgical loading unit.

Background of Related Art

Various types of surgical instruments used to endoscopically treat tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical stapling instrument. Typically, surgical stapling instruments include an end effector having an anvil assembly and a cartridge assembly for supporting an array of surgical staples, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical staples from the cartridge assembly.

During laparoscopic or endoscopic surgical procedures, access to a surgical site is achieved through a small incision or through a narrow cannula inserted through a small entrance wound in a patient. Because of limited area available to access the surgical site, many endoscopic instruments include mechanisms for articulating the end effector of the instrument in relation to a body portion of the instrument to improve access to tissue to be treated. In addition, some end effectors have a knife blade that translates therethrough to tissue grasped by jaws of the end effector. During articulation of the end effector, the knife blade experiences a bending moment and/or a shear force that may degrade the knife blade over continued articulation of the end effector.

Accordingly, it would be beneficial to provide an improved surgical instrument, which includes a mechanism for articulating the end effector relative to the body portion in a variety of orientations without damaging a knife blade that moves through the end effector.

SUMMARY

In one aspect of the present disclosure, a surgical loading unit is provided that includes an elongate body, an end effector having a proximal portion pivotably coupled to a distal portion of the elongate body, and a knife assembly disposed within the elongate body. The knife assembly includes an elongate guide member and a flexible knife bar. The elongate guide member is pivotably supported in the distal portion of the elongate body. The knife bar is configured to move through a longitudinally-extending channel defined through the elongate guide member. Articulation of the end effector relative to the elongate body in a first direction effects movement of a distal portion of the elongate guide member in a second direction, opposite the first direction.

In some embodiments, the elongate body may define a first longitudinal axis and the end effector may define a second longitudinal axis. The end effector may be configured to move relative to the elongate body from a first position in which the second longitudinal axis is aligned with the first longitudinal axis to a second position in which the second longitudinal axis is misaligned with the first longitudinal axis. Upon the end effector moving to the second position, a distal portion of the end effector may be disposed on a first side of a central longitudinal axis defined by the elongate body and the distal portion of the elongate guide member of the knife assembly may be disposed on a second side of the central longitudinal axis defined by the elongate body.

It is contemplated that the knife bar may be more flexible than the elongate guide member such that the elongate guide member is configured to maintain a linear shape as a segment of the knife bar that is located distally of the elongate guide member flexes during articulation of the end effector.

It is envisioned that the knife assembly may further include a pair of blow-out plates extending along opposite sides of the knife bar. The pair of blow-out plates may have a distal portion coupled to the proximal portion of the end effector. A first blow-out plate may have a proximal portion disposed between a first lateral side of the knife bar and a first lateral side of the elongate guide member, and a second blow-out plate may have a proximal portion disposed between a second lateral side of the knife bar and a second lateral side of the elongate guide member. The proximal portion of the first blow-out plate may be configured to slide relative to the elongate guide member in a first axial direction, and the proximal portion of the second blow-out plate may be configured to slide relative to the elongate guide member in a second axial direction in response to the end effector articulating.

In some embodiments, the proximal portion of the end effector may include first and second walls that taper proximally such that the first and second walls cooperatively define a proximally-flaring cavity through which both the distal portion of the knife bar and the pair of blow-out plates extend. Each of the first and second walls may define arcuate side surfaces that are laterally spaced from one another. The arcuate side surface of the first wall may be configured to contact the first blow-out plate when the end effector articulates in the first direction, and the arcuate side surface of the second wall may be configured to contact the second blow-out plate when the end effector articulates in the second direction.

It is contemplated that a proximal portion of the first wall may be configured to contact the first blow-out plate in response to an articulation of the end effector in the first direction to move the distal portion of the elongate guide member in the second direction. The proximal portion of the second wall may be configured to contact the second blow-out plate in response to an articulation of the end effector in the second direction to move the distal portion of the elongate guide member in the first direction.

It is envisioned that a proximal portion of the first wall may be configured to move the distal portion of the elongate guide member in the second direction in response to an articulation of the end effector in the first direction, and a proximal portion of the second wall may be configured to move the distal portion of the elongate guide member in the first direction in response to an articulation of the end effector in the second direction.

In some embodiments, the elongate guide member may include a proximal portion pivotably coupled to the elongate body. The proximal portion of the elongate guide member may have a circular tab pivotably coupled to the elongate body, such that the elongate guide member is prevented from translating longitudinally relative to the elongate body.

It is contemplated that the knife assembly may further include a track defining a longitudinally-extending channel. The flexible knife bar may include a first knife bar shaft and a second knife bar shaft coupled to and extending parallel with the first knife bar shaft. The first knife bar shaft may extend through the channel of the elongate guide member. The second knife bar shaft may extend through the channel of the track.

It is envisioned that the track and the elongate guide member may be less flexible than the knife bar, such that the track and the elongate guide member are configured to maintain a linear shape during articulation of the end effector relative to the elongate body.

In some embodiments, the surgical loading unit may further include a support structure disposed between the first and second knife bar shafts of the flexible knife bar. The support structure may include a top surface on which the elongate guide member is supported, and a bottom surface on which the track is supported.

In some aspects, the elongate body may include a support structure on which the knife assembly is supported. The support structure may have a distal portion pivotably coupled to the proximal portion of the end effector. The support structure may have a planar top surface that defines a distally-flaring cavity therein. The elongate guide member may be disposed within the distally-flaring cavity.

It is contemplated that the elongate body may include an articulation assembly for effecting articulation of the end effector. The articulation assembly may include an elongated drive nut extending through a proximal portion of the support structure, an elongated drive screw extending through a distal portion of the support structure and having a proximal portion threadingly coupled to the drive nut, and an articulation link having a proximal portion pivotably coupled to a distal portion of the drive screw, and a distal portion pivotably coupled to the proximal portion of the end effector. Rotation of the drive nut may axially move the drive screw to pivot the articulation link and, in turn, articulate the end effector.

It is envisioned that the articulation assembly may be laterally offset from a central longitudinal axis defined by the elongate body.

In some embodiments, the knife bar may have a proximal portion operably coupled to an actuator for axially moving the knife bar through the elongate body, and a distal portion that supports a knife blade for cutting tissue. The end effector may include a staple cartridge and an anvil. The staple cartridge may define a longitudinally-extending channel dimensioned for slidable receipt of the knife blade.

In another aspect of the present disclosure, a surgical loading unit is provided that includes an elongate body, an end effector having a proximal portion pivotably coupled to a distal portion of the elongate body, and a flexible knife bar extending through the distal portion of the elongate body and the proximal portion of the end effector. Articulation of the end effector relative to the elongate body in a first direction may curve a first segment of the knife bar in the first direction and may pivot a second segment of the knife bar in a second direction, opposite the first direction, while the second segment maintains a linear shape. The second segment may be disposed proximally of the first segment.

