Articulating clip applier

[0001] The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/368,349 filed on Jul. 28, 2010, the entire contents of which are incorporated herein by reference.

[0002] 1. Technical Field

[0003] The present disclosure relates to surgical clip appliers and, more particularly, to an articulating endoscopic surgical fastener applier.

[0004] 2. Background of Related Art

[0005] Endoscopic staplers and clip appliers are known in the art and are used for a number of distinct and useful surgical procedures. In the case of a laparoscopic surgical procedure, access to the interior of an abdomen is achieved through narrow tubes or cannulas inserted through a small entrance incision in the skin. Minimally invasive procedures performed elsewhere in the body are often generally referred to as endoscopic procedures. Typically, a tube or cannula device is extended into the patient's body through the entrance incision to provide an access port. The port allows the surgeon to insert a number of different surgical instruments therethrough using a trocar and for performing surgical procedures far removed from the incision.

[0006] During a majority of these procedures, the surgeon must often terminate the flow of blood or another fluid through one or more vessels. The surgeon will often apply a surgical clip to a blood vessel or another duct to prevent the flow of body fluids therethrough during the procedure. An endoscopic clip applier is known in the art for applying a single clip during an entry to the body cavity. Such single clip appliers are typically fabricated from a biocompatible material and are usually compressed over a vessel. Once applied to the vessel, the compressed clip terminates the flow of fluid therethrough.

[0007] Endoscopic clip appliers that are able to apply multiple clips in endoscopic or laparoscopic procedures during a single entry into the body cavity are described in commonly assigned U.S. Pat. Nos. 5,084,057 and 5,100,420 to Green et al., which are both incorporated by reference in their entirety. Another multiple endoscopic clip applier is disclosed in commonly assigned U.S. Pat. No. 5,607,436 to Pratt et al., the contents of which is also hereby incorporated by reference herein in its entirety. These devices are typically, though not necessarily, used during a single surgical procedure. U.S. patent application Ser. No. 08/515,341 now U.S. Pat. No. 5,695,502 to Pier et al., the disclosure of which is hereby incorporated by reference herein, discloses a resterilizable surgical clip applier. The clip applier advances and forms multiple clips during a single insertion into the body cavity. This resterilizable clip applier is configured to receive and cooperate with an interchangeable clip magazine to advance and form multiple clips during a single entry into a body cavity. One significant design goal is that the surgical clip be loaded between the jaws without any compression of the clip from the loading procedure.

[0008] Endoscopic or laparoscopic procedures are often performed remotely from the incision. Consequently, application of clips may be complicated by a reduced field of view or reduced tactile feedback for the user at the proximal end of the device. It is therefore desirable to improve the operation of the instrument by providing an instrument that is capable of articulating.

[0009] The present disclosure relates to surgical clip appliers.

[0010] According to an aspect of the present disclosure, a surgical apparatus for application of surgical clips to body tissue is provided and includes a housing, a drive assembly, a shaft assembly, and a trigger. The shaft assembly extends distally from the housing. The drive assembly is at least partially positioned within the housing. The trigger is operatively connected to the drive assembly.

[0011] The shaft assembly has a first tubular member and a second tubular member located distally from the first tubular member. The first tubular member defines a longitudinal axis. The first tubular member and the second tubular member are pivotally connected through a common pivot axis. The pivot axis is perpendicular to the longitudinal axis. The drive assembly may include a flexible cable that transfers both a translational force and a rotational force from inside of the housing into the second tubular member.

[0012] An articulation mechanism operatively connects the first tubular member and the second tubular member. The articulation mechanism includes a gear rack, at least one gear and a gear segment. The gear rack has a plurality of teeth longitudinally placed thereon and is located within the first tubular member. The at least one gear is operatively connected with the gear rack within the first tubular member. The gear segment extends proximally from the second tubular member and is operatively connected with the at least one gear. The gear segment is fixed with respect to the second tubular member. The articulation mechanism pivots the second tubular member about the pivot axis at an angle of up to 90° from the longitudinal axis. The articulating mechanism may include a control knob that is rotatable to pivot the second tubular member.

[0013] The second tubular member may include a jaw assembly and a clip cartridge containing a plurality of fasteners disposed therein.

[0014] The surgical clip applying apparatus may include a rotation mechanism. The rotation mechanism is operatively connected with and provides a rotational force to the jaw assembly. The rotation mechanism may include a dial and a band. The band is located about a proximal portion of the drive assembly. The dial defines an internal passage and an inner surface. The band defines a contoured outer surface that receives and transmits a rotational force from the inner surface of the dial to the drive assembly. The dial is slidably coupled with the band.

[0015] The second tubular member may include two substantially parallel gear segments.

[0016] In another embodiment, a surgical apparatus for application of surgical clips to body tissue is provided and includes a housing, a drive assembly, a shaft assembly, and a trigger. The shaft assembly extends distally from the housing.

[0017] The shaft assembly has a first tubular member and a second tubular member located distally from the first tubular member. The first tubular member defines a first longitudinal axis, around which the first tubular member may be rotated. The first tubular member and the second tubular member are pivotally connected through a common pivot axis.

[0018] The second tubular member defines a second longitudinal axis. A distal portion of the second tubular member is rotatable about the second longitudinal axis. The second tubular member includes a geared segment extending proximally from a proximal portion thereof.

[0019] The drive assembly is at least partially positioned within the housing and extends through the first tubular member and partially into the second tubular member. The drive assembly may include a flexible cable to transfer both a translational force and a rotational force from inside of the housing into the second tubular member. The trigger is operatively connected to the drive assembly.

[0020] A rack extends along a portion of the longitudinal axis. The rack is located within the first tubular member and reciprocates along the first longitudinal axis. The rack is operatively connected with the geared segment.

[0021] The surgical clip applying apparatus may include an articulation mechanism that provides a pivotal force to pivot the second tubular member about the pivot axis at an angle of up to 90° from the first longitudinal axis. The articulating mechanism includes a control knob being rotatable to retract the rack proximally and to extend the rack distally.

[0022] The surgical clip applying apparatus may further include a rotation mechanism. The rotation mechanism is operatively connected with the drive assembly to provide a rotational force to the distal portion of the second tubular member. The rotation mechanism includes a dial and a band located about a proximal portion of the drive assembly. The dial defines an internal passage and an inner surface. The band defines a contoured outer surface that is able receive and transmit a rotational force from the inner surface of the dial to the proximal portion of the drive assembly. The dial is slidably coupled with the band.

[0023] The second tubular member may include a jaw assembly and a clip cartridge containing a plurality of clips disposed therein. The rotation mechanism may be connected with and provide a rotational force to the jaw assembly.

[0024] According to another aspect of the present disclosure, an end effector for operative connection to a surgical handle assembly including an axially reciprocatable drive assembly having a flexible drive cable operatively connected to the end effector is provided. The end effector includes a distal housing portion defining a proximal end, a distal end, and a longitudinal axis; a knuckle portion extending proximally from the proximal end of the distal housing portion, the knuckle portion being bifurcated into a first geared portion and a second geared portion, the distal housing portion being rotatably mounted to the knuckle portion to allow the distal housing portion to rotate about the longitudinal axis with respect to the knuckle portion; a jaw assembly extending distally from the base portion, the jaw assembly including a first jaw and a second jaw movable between a spaced apart position and an approximated position; a plurality of surgical clips loaded in the housing in a partially stacked fashion; and a jaw closure mechanism disposed in the distal housing portion and operatively associated with the jaw assembly and the plurality of surgical clips. A distal end of the flexible drive cable is connected to the jaw closure mechanism so as to transmit an operative force to the jaw closure mechanism when the longitudinal axis of the distal housing portion is either axially aligned or angled with respect to a longitudinal axis of the surgical handle. The jaw closure mechanism feeds a clip into the jaw assembly and forms the fed clip upon a single complete stroke of the flexible drive cable.

[0025] The end effector may further include a proximal housing pivotably connected to the knuckle portion; and a gear train supported in the proximal housing. A distal-most gear of the gear train may be operatively engaged with the first geared portion and the second geared portion of the knuckle portion.

[0026] The end effector may further include a rack slidably supported in the proximal housing, wherein the rack defines at least one axial row of gear teeth, and wherein the axial row of gear teeth is engaged with a proximal-most gear of the gear train.

[0027] In use, axial displacement of the rack relative to the cover results in articulation of the distal housing portion relative to the proximal housing portion.

[0028] According to a further aspect of the present disclosure, an end effector for application of surgical clips to body tissue is provided. The end effector includes a portion defining a proximal end, a distal end, and a longitudinal axis; a knuckle portion extending proximally from the proximal end of the base portion, the knuckle portion being bifurcated into a first geared portion and a second geared portion, the base portion being rotatably mounted to the knuckle portion to allow the base portion to rotate about the longitudinal axis with respect to the knuckle portion; a jaw assembly extending distally from the base portion, the jaw assembly including a first jaw and a second jaw movable between a spaced apart position and an approximated position; and a plurality of fasteners located within the base portion, each of the plurality of fasteners having a pair of legs extending from a backspan, each of the plurality of fasteners defining a fastener axis extending in a direction substantially parallel to the pair of legs, each of the plurality of fasteners being arranged within the base portion to form an angle between the fastener axis and the longitudinal axis, each of the plurality of fasteners being located adjacent to another of the plurality of fasteners to form a stack.

[0029] The knuckle may include a pivot structure that defines a pivot axis.

[0030] The end effector may further include a jaw closure mechanism operatively connected to the jaw assembly, the jaw closure mechanism providing an approximating force to the first jaw and the second jaw.

[0031] The knuckle portion may include a plurality of teeth.

[0032] The plurality of fasteners may be stacked in a non-colinear position with respect to the second longitudinal axis.

[0033] The first jaw and the second jaw may be angled with respect to the longitudinal axis.

[0034] The legs of the plurality of fasteners may be disposed in a substantially parallel orientation to the first jaw and the second jaw.

[0035] The fasteners may have a U-shape or a V-shape. The stack of fasteners may extend parallel to the longitudinal axis.

[0036] The end effector may further include a proximal housing portion connected to knuckle portion such that base portion is pivotable off-axis with respect to the cover. The proximal housing portion may support a gear train in a distal region thereof, and wherein a distal-most gear of the gear train may be operatively engaged with the first geared portion and the second geared portion of the knuckle portion. The end effector may further include a rack slidably supported in a proximal region of the proximal housing portion, wherein the rack defines at least one axial row of gear teeth, and wherein the axial row of gear teeth is engaged with a proximal-most gear of the gear train.

[0037] In use, axial displacement of the rack relative to the proximal housing portion may result in articulation of the base portion relative to the proximal housing portion.

[0038] According to yet another aspect of the present disclosure, an end effector for operative connection to a surgical handle assembly including an axially reciprocatable drive assembly having a flexible drive cable operatively connected to the end effector is provided. The end effector includes a distal housing portion defining a proximal end, a distal end and a longitudinal axis; a proximal housing portion defining a proximal end, a distal end and a longitudinal axis; a knuckle portion interconnecting the proximal end of the distal housing portion and the distal end of the proximal housing portion, wherein the knuckle portion permits rotation of the distal housing portion relative thereto and articulation of the distal housing portion relative to the proximal housing portion; a jaw assembly supported in the distal end of the distal housing portion, the jaw assembly including a first jaw and a second jaw movable between a spaced apart position and an approximated position; and a plurality of fasteners loaded within the distal housing portion, each of the plurality of fasteners having a pair of legs extending from a backspan, each of the plurality of fasteners defining a fastener axis extending in a direction substantially parallel to the pair of legs, each of the plurality of fasteners being arranged within the base portion such that the fastener axis is disposed at an angle with respect to the longitudinal axis of the distal housing portion, and wherein the plurality of fasteners are arranged in a stack.

[0039] The end effector may further include a jaw closure mechanism operatively connected to the jaw assembly, wherein the jaw closure mechanism provides an approximating force to the first jaw and the second jaw upon a proximal movement thereof relative to the first jaw and the second jaw.

[0040] The jaw closure mechanism may include a cam plate axially slidably supported in the distal housing portion, wherein the cam plate includes a camming aperture formed therein, wherein the camming aperture has a substantially “V” shaped profile, and wherein each of first jaw and second jaw includes a post extending therefrom and into the camming aperture of the cam plate. In use, movement of the cam plate proximally relative to the first jaw and second jaw engages an edge of the camming aperture against the nubs of the first jaw and the second jaw to approximate the first jaw and the second jaw.

[0041] The cam plate may include a protrusion extending distally into the camming aperture; wherein movement of the cam plate distally relative to the first jaw and second jaw engages the protrusion of the camming aperture between the nubs of the first jaw and the second jaw to separate the first jaw and the second jaw.

[0042] The flexible drive cable may extend between the distal housing portion and the proximal housing portion, and across the knuckle portion.

[0043] A proximal end of the drive cable may be connected to a drive assembly and a distal end of the drive cable may be connected to a block member slidably supported in the base portion, wherein distal movement of the drive cable results in distal movement of the block member to distally advance a feed bar and load a fastener into the jaw assembly.

[0044] The end effector may further include a cam plate axially slidably supported in the base portion; wherein the block member includes a finger extending into a proximal axially extending slot provided in the cam plate; wherein the cam plate includes a camming aperture formed therein; wherein the camming aperture has a substantially “V” shaped profile, and wherein each of first jaw and second jaw includes a post extending therefrom and into the camming aperture of the cam plate. In use, distal movement of the block member may result in distal movement of the cam plate and proximal movement of the block member results in proximal movement of the cam plate. Additionally, in use, movement of the cam plate proximally relative to the first jaw and second jaw engages an edge of the camming aperture against the nubs of the first jaw and the second jaw to approximate the first jaw and the second jaw.

[0045] The cam plate may include a protrusion extending distally into the camming aperture, wherein movement of the cam plate distally relative to the first jaw and second jaw engages the protrusion of the camming aperture between the nubs of the first jaw and the second jaw to separate the first jaw and the second jaw.

[0046] The cam plate may be biased to a distal position.

[0047] The end effector may further include a clip follower disposed proximally of the plurality of fasteners, wherein the clip follower is biased in a distal direction to urge the plurality of fasteners distally.

[0048] The knuckle portion may be bifurcated into a first geared portion and a second geared portion.

[0049] The proximal housing portion may support a gear train in a distal region thereof, and wherein a distal-most gear of the gear train is operatively engaged with the first geared portion and the second geared portion of the knuckle portion.

[0050] The end effector may further include a rack slidably supported in a proximal region of the proximal housing portion, wherein the rack defines at least one axial row of gear teeth, and wherein the axial row of gear teeth is engaged with a proximal-most gear of the gear train.

[0051] In use, axial displacement of the rack relative to the proximal housing portion results in articulation of the distal housing portion relative to the proximal housing portion such that the longitudinal axis of the distal housing portion is angled with respect to the longitudinal axis of the proximal housing portion.

[0111] Other features of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the present disclosure.

[0112] Embodiments of surgical clip appliers in accordance with the present disclosure will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical structural elements. As shown in the drawings and described throughout the following description, as is traditional when referring to relative positioning on a surgical instrument, the term “proximal” refers to the end of the apparatus which is closer to the user and the term “distal” refers to the end of the apparatus which is further away from the user.

[0113] With reference to FIG. 1, reference numeral 100 designates an embodiment of the presently disclosed surgical clip applier. In the interest of brevity, the present disclosure focuses on an articulation mechanism and a clip applying end mechanism of surgical clip applier 100. U.S. Pat. No. 7,637,917, filed on Oct. 7, 2005, describes in detail the structure and operation of a surgical clip applier that may incorporate the presently disclosed articulation mechanism and a clip applying end mechanism, the entire content of which is incorporated herein by reference.

[0114] Clip applier 100 includes a handle assembly 200 and an articulating endoscopic portion or a shaft assembly 300 extending distally from handle assembly 200. Referring now to FIGS. 5, 5A, 5B-8, handle assembly 200 of surgical clip applier 100 is shown. Handle assembly 200 includes a housing 202 having a first or right side half-section 202a and a second or left side half-section 202b. Handle assembly 200 includes a trigger 208 pivotably supported between right side half-section 202a and left side half-section 202b. Housing 202 of handle assembly 200 may be formed of a suitable plastic material.

[0115] As seen in FIGS. 1-15, the shaft assembly 300 includes a first tubular member 302 and a second tubular member or an end effector 500. The first tubular member 302 defines a first longitudinal ‘X1’ axis and the end effector 500 defines a second longitudinal ‘X2’ axis. The end effector 500 is located distally from the first tubular member 302. The first tubular member 302 and the end effector 500 are pivotally connected to each other through a common pivot ‘Z’ axis. The common pivot ‘Z’ axis is substantially perpendicular to both the first longitudinal ‘X1’ axis and the second longitudinal ‘X2’ axis. Shaft assembly 300 and the components thereof may be formed of suitable biocompatible materials, such as, for example, stainless steel, titanium, plastics, and the like.

[0116] As seen in FIG. 5, the first tubular member 302 has a rotation mechanism 304, and an articulation mechanism 320. The rotation mechanism 304 allows the first tubular member 302 to rotate, with respect to housing 202, about the first longitudinal ‘X1’ axis. The rotation mechanism 304 includes a rotation knob 306 that is rotatably coupled to the housing 202 and an outer tube 310. The rotation knob 306 is supported between the housing half-sections 202a, 202b.

[0117] As seen in FIGS. 5 and 6, the outer tube 310 is at least partially supported by rotation knob 306, and has a proximal end 310a and a distal end 310b. The outer tube 310 defines a lumen 312, extending longitudinally therethrough, and a pair of openings 314, formed near the proximal end 310a of the outer tube 310. With reference to FIGS. 20 and 21, the rotation knob 306 has a pair of nubs 307 that extend into and interface with the openings 314 of the outer tube 310. In use, as seen in FIG. 1, rotation of the rotation knob 306 causes the outer tube 310 to rotate about the first longitudinal ‘X1’ axis and thus results in the rotation of the entire shaft assembly 300.

[0118] As seen in FIG. 5A, clip applier 100 includes a drive assembly 220 operatively connected to trigger 208. The drive assembly 220 is at least partially positioned within the housing 202 of handle assembly 200 and extends through the first tubular member 302 and at least partially into the end effector 500. The drive assembly 220 is able to transfer both a translational force and a rotational force into the end effector 500.

[0119] The trigger 208 is operatively connected to a link 210. Link 210 may be connected to an electrical motor 212, which is connected with a drive member 226. The drive member 226 is rotatably attached to the proximal end 222a of the drive rod 222 via a coupling 230 that allows the drive rod 222 to rotate with respect to the drive member 226.

[0120] The drive rod 222 may have a cylindrical shape and may extend at least partially along the first tubular member 302. With additional reference to FIG. 44, drive assembly 220 includes a flexible drive cable 224 mounted to the distal end 222b of the drive rod 222. Drive cable 224 extends distally from drive rod 222 and into the end effector 500. It is envisioned that the drive cable 224 may have a cross-sectional shape that is non-circular.

[0121] As seen in FIGS. 5-5B, clip applier 100 further includes a positioning mechanism 530. The positioning mechanism 530 is operatively connected with the drive assembly 220 to provide a rotational force to a distal portion or clip cartridge 550 of the end effector 500. As seen in FIG. 5A, the positioning mechanism 530 includes a rotation knob 306, portions of the drive rod 222, and portions of the drive cable 224.

[0122] The drive rod 222 includes a contoured outer surface or shaped band 232 that is complimentary to an aperture 242 defined in a mounting member 240 that supports drive rod 222. The aperture 242 is sized slightly larger than the shaped band 232 of the drive rod 222. The over sized aperture 242 allows for longitudinal movement of the drive rod 222 through the aperture 242. The drive rod 222 is able to freely rotate within the first tubular member 302, which allows the drive rod 222 to receive and transmit a rotational force from the rotation knob 306 to the proximal portion of the drive assembly 220.

[0123] As seen in FIG. 5, clip applier 100 includes an articulation mechanism 320 operatively connecting the first tubular member 302 with the end effector 500. The articulation mechanism 320 provides a pivot force to the end effector 500 to pivot the end effector 500 about the pivot axis at an angle of up to about 90° relative to the first longitudinal ‘X1’ axis.

[0124] As seen in FIGS. 6 and 12-18, articulation assembly 320 includes an articulation knob 322 rotatably supported by and projecting distally from the rotation knob 306 (FIG. 5A). With reference to FIG. 21, articulation knob 322 has an internal thread 324 that is sized to accept and compliment an external thread 332 (FIG. 8) of an articulation screw 330. As seen in FIG. 8, articulation screw 330 includes a first or right hand half section 330a and a second or left hand section 330b. Each section 330a, 330b has a nub 334 projecting radially inward from an inner curved surface 336. Each nub 334 extends through a slot 316 (FIG. 6) defined in the outer tube 310 and into a radial recess 342 of an articulation plunger 340 (FIG. 7).

[0125] Articulation assembly 320 includes an articulation plunger 340 that extends between a proximal end 340a, located proximally of nubs 334 of articulation screw 330 and outer tube 310. Articulation plunger 340 defines a lumen 346 sized to allow passage of the drive rod 222 therethrough. The articulation plunger 340 terminates in a distal end 340b having a mushroom shaped head 344. The mushroom shaped head 344 has a larger distal portion 344b than proximal portion 344a.

[0126] With reference to FIGS. 6-7 and 9-11, clip applier 100 includes a shaft 350 defining a proximal portion 352 having a proximal end 350a, a distal portion 354 having a distal end 350b, and a center portion 350c. The shaft 350 is semi-cylindrical in shape to allow the drive rod 222 to pass therealong, and extends longitudinally within the outer tube 310. As shown in FIG. 4, the proximal end 350a and the distal end 350b of shaft 350 are curved in an opposite transverse direction than the center portion 350c. Shaft 350 defines a distal aperture that separates the distal portion 354 from the center portion 350c and a proximal aperture that separates the proximal portion 352 from the center portion 350c. The distal aperture of shaft 350 is sized and configured to accept the distal portion 334b of head 344 of the articulation plunger 340 therein and the distal portion forms an arc that is sized and configured to loosely set about distal portion 344b of head 344 of the articulation plunger 340.

[0127] As seen in FIG. 11, the proximal portion 352 of the shaft 350 removably couples the shaft 350 to a rack 360. A proximal end 362a of the rack 360 is formed in a mushroom shaped tail 362. The proximal end 362a of the mushroom shaped tail 362 is larger than the distal end 362b of the mushroom shaped tail 362. The proximal aperture of the shaft 350 is sized to accept the proximal end 362b of the mushroom shaped tail 362 therein. The proximal portion 352 of shaft 350 forms an arc that is sized to set loosely about distal end 362b of the mushroom shaped tail 362 of the rack 360.

[0128] As seen in FIG. 11, rack 360 includes a cylindrical section 363 and a proximal end 362b disposed immediately adjacent to cylindrical section 363 and that is sized slightly smaller than an inner diameter of the outer tube 310. The cylindrical section 363 may have one or more recesses 364 about the perimeter that are sized to accept an O-seal 382 therein, as shown in FIG. 17. The O-seal 382 is deformable to fill the space between the cylindrical section 363 of the rack 360 and the inner diameter of the outer tube 310 to substantially seal the distal portion of the first tubular member 302.

[0129] As shown in FIG. 11, the rack 360 defines a central passageway 365 along the first longitudinal ‘X1’ axis sized to allow passage of the drive cable 226 therethrough. A distal portion 366 of the rack 360 has a rectangular cross-sectional shape. With reference to FIGS. 12 and 14, the distal portion 366 is sized to fit through the longitudinal center of a helical spring 380. The spring 380 has an outer diameter sized to be slightly smaller than the cylindrical section 363 of the rack 360. As a result, the spring is prevented from passing proximally beyond the cylindrical section 363 of the rack 360.

[0130] As shown in FIGS. 11 and 12, the distal portion 366 of rack 360 includes at least two protrusions 367 and a set of longitudinally aligned linear teeth 368. The two protrusions 367 extend outward in opposite directions from the proximal portion 366 and are aligned and sized to be placed into slots 391 defined in an inner surface 392 of an end cover 390. As seen in FIG. 12, the end cover 390 has a right hand side cover 390a and a left hand side cover 390b. The outer proximal portion 393 of end cover 390 defines an outer diameter that is sized to enable the end cover 390 to be pressed into the distal end 310b of the outer tube 310 and establish an interference fit between the end cover 390 and the outer tube 310.

[0131] The inner surface 392 of the end cover 390 has a rectangular shape that is sized to be slightly larger than the rectangular cross-section of the rack 360 to allow at least partial longitudinal movement of the rack 360 therein. A proximal end 394a of the end cover 390 is sized to be smaller than the spring 380 to provide a biasing surface for the spring 380. As seen in FIGS. 14 and 15, the spring 380 is interposed between a distal surface 363a of the cylindrical portion 363 and the proximal end 394a of the end cover 390 to bias the rack 360 proximally.

[0132] As seen in FIGS. 12 and 16, the inner surface 392 of the end cover sections 390a, 390b define a series of three circular recesses 396a, 396b, and 396c. Each of the three circular recesses 396a, 396b, and 396c are centered about an aperture 397a, 397b, and 397c through each of the end cover sections 392a, 392b.

[0133] As stated above, the rack 360 is located within the outer tube 310 and extends into the end cover 390. The rack 360 is configured to reciprocate along the first longitudinal ‘X1’ axis. A proximal position and a distal position of the rack 360 is defined by the two protrusions 367 that are located within respective slots 391 of end cover 390. The two protrusions 367 of rack 360, acting against the proximal end 391a of the slots 391, define the proximal-most position of the rack 360. The two protrusions 367 of rack 360, acting against the distal end 391b of the slots 391, define the distal-most position of the rack 360.

[0134] While rack 360 includes a pair of opposed longitudinally arranged teeth 368 that engage respective gear sets and mating structure, only a single set of teeth 368 of rack 360 and a single respective gear set and mating structure will be described herein for the purpose of clarity. As shown in FIGS. 12-18, rack 360 has a pair of longitudinally arranged teeth 368 on opposing sides of the distal portion 366. The longitudinally arranged teeth 368 are defined by recesses 369 in the distal portion 366 that form the distal portion 366 into an “I” beam, wherein the longitudinally arranged teeth 368 are formed along an inside of flanges of the “I” beam that extend in opposing directions. The longitudinally arranged teeth 368 are in intimate contact with a first gear 420 supported in end cover 390.

[0135] As seen in FIG. 12A, the first gear 420 defines a center aperture 421, a circular base 422, a first circular set of teeth 423, and a second circular set of teeth 424. The first circular set of teeth 423 is smaller in diameter than and stacked upon the second set of teeth 424. The circular base 422 forms a substantially similar outer diameter as the second set of teeth 424. As seen in FIG. 12, a first pin 410 has a head portion 410a that is larger than the aperture 421 of first gear 420, a body portion 410b slightly smaller in diameter than the center aperture 421, and a tail portion 410c that is sized to allow the first pin 410 to be press fit into the aperture 397a in the cover 390. An interference fit between the tail portion 410c and the cover 390 retains the tail portion 410c in the aperture 397a and holds the first gear 420 at least partially within the first recess 396a of the end cover 390. The longitudinally arranged teeth 368 of the rack 360 and the first gear 420 are connected, such that longitudinal movement of the rack 360 relative to first gear 420 results in a rotational movement in a first direction of the first gear 420.

[0136] The first gear 420 is operatively connected with a second gear 430 of the gear set. As seen in FIG. 12B, the second gear 430 defines a center aperture 431, a raised base 432, and a circular set of teeth 433. The raised base 432 is circular in cross-sectional shape and has a substantially smaller outer diameter than the circular set of teeth 423. A second pin 411 has a head portion 411a that is larger than the aperture 431, a body portion 411b that is slightly smaller in diameter than the center aperture 431, and a tail portion 411c that is sized to allow the second pin 411 to be press fit into the aperture 397b in the cover 390. An interference fit between the tail portion 411c and the cover 390 retains the tail portion 411c in the aperture 397b and holds the second gear 430 at least partially within the second recess 396b of the end cover 390. The second circular set of teeth 424 of the first gear 420 is interconnected with the circular set of teeth 433 of the second gear 430, such that rotational movement of the first gear 420 in a first direction results in a rotational movement of the second gear 430 in a second direction.

[0137] The second gear 430 is operatively connected with a third gear 440 of the gear set. As seen in FIG. 12c, the third gear 440 defines a center aperture 441, a circular base 442, and a circular set of teeth 443. The circular base 442 forms a substantially similar outer diameter as the circular set of teeth 443. The circular base 442 is substantially equal in height as both the raised base 432 of the second gear 430 and the circular base 422 of the first gear 420. A third pin 412 has a head portion 412a that is larger than the aperture 441, a body portion 412b that is slightly smaller in diameter than the center aperture 441, and a tail portion 412c that is sized to allow the third pin 412 to be press fit into the aperture 397c in the cover 390. An interference fit between the tail portion 412c and the cover 390 retains the tail portion 412c in the aperture 397c and holds the third gear 440 at least partially within the second recess 396c of the end cover 390. The circular set of teeth 433 of the second gear 40 is interconnected with the circular set of teeth 444 of the third gear 440, such that rotational movement of the second gear 430 in the second direction results in a rotational movement of the third gear 440 in the first direction.

[0138] Located distally of the third gear 440, each of the end cover sections 392a, 392b defines a boss 398 extending radially inward from the distal portion 395b of the end cover sections 392a, 392b. The bosses 398 capture and secure a cylindrical distal, portion 522 of the end effector 500 to the first tubular member 302.

[0139] As seen in FIG. 12, cylindrical distal portion 522 of the end effector 500 has a knuckle 510. The knuckle 510 includes a bifurcated proximal portion 514 and a cylindrical distal portion 522. The bifurcated proximal portion 514 defines a pivoting aperture 511 that is perpendicular to both the first longitudinal ‘X1’ axis and the second longitudinal ‘X2’ axis. The pivoting aperture 511 defines the pivot ‘Z’ axis. The pivoting aperture 511 is circular in cross-sectional shape and is sized to accept the bosses 398 therein. The size and alignment of the bosses 398 allow the end cover sections 392a, 392b to sandwich the knuckle 510 therebetween. As a result of the circular bosses 398 projecting into the circular pivoting aperture 511, the end effector 510 is able to pivot or swing about the ‘Z’ axis.

[0140] The bifurcated proximal portion 514 of knuckle 510 includes two gear segments 516a, 516b that are integrally formed therewith and that extend proximally about the proximal end 510a of the knuckle 510. Each gear segment 516 defines an arcuate set of teeth 517 that are operatively connected with the third gear 440.

[0141] The knuckle 510 further defines a lumen 518 through the center thereof, and a circular channel 520 about the cylindrical distal portion 522. The circular channel 520 is located proximally from the distal end 510b of the knuckle 510. The center lumen 518 is sized to allow at least partial passage of the drive cable 224 therethrough and at least partially into a clip cartridge 550 (FIGS. 24 and 27) of the end effector 500.

[0142] The operation of the articulation mechanism will now be discussed in reference to FIGS. 6-21. With specific reference to FIGS. 20 and 21, rotation of the articulation knob 322 (FIG. 5) with respect to the rotation knob 306 and the outer tube 310 produces longitudinal movement of the articulation screw 330 by causing the internal thread 324 of the articulation knob 322 to react against the external thread 332 of the articulation screw 330. The articulation screw 330 is rotationally fixed with respect to the outer tube 310 by the nubs 334. As a result, the articulation screw 330 can only move longitudinally as the articulation knob 332 is rotated about the articulation screw 330. Therefore, rotation of the articulation knob 322 in a first direction causes the movement of the articulation screw 330 in distal direction and rotation of the articulation knob 322 in a second direction causes the movement of the articulation screw 330 in proximal direction.

[0143] Axial movement of the articulation screw 330 causes the nubs 334 to react against the articulation plunger 340 to cause longitudinal movement of the articulation plunger 340 in the same direction. Movement of the articulation plunger 340 causes longitudinal movement of the shaft 350 and, in turn, longitudinal movement of the rack 360.

[0144] As discussed above, the first gear 420 is operatively connected with the linear teeth 368 of the rack 360. With specific reference to FIGS. 17 and 18, as the rack 360 is forced to move proximally, the first gear 420 is rotated in a first direction causing the second gear 430 to be rotated in a second direction. The second gear 430 causes the third gear 440 to be rotated in the same direction as the first gear 420. The third gear 440 reacts against the geared segments 516 causing the second tubular member 302 to pivot about the pivot ‘Z’ axis.

[0145] As seen in FIGS. 1-6, end effector 500 is in the form of a surgical clip applier and is configured to support a clip cartridge 550. As seen in FIG. 27, clip cartridge 550 has a housing or base portion 560 and a cover 590. With reference to FIG. 28, the housing 560 includes a proximal portion 561a and a distal portion 561b. The proximal portion 561a of housing 560 is cylindrical in shape and defines a longitudinal passageway 562 therethrough. The longitudinal passageway 562 is co-axially located with the second longitudinal ‘X2’ axis and transitions, as seen in FIGS. 22 and 23, from a larger cylindrical portion 562a of the passageway 562, sized to accept the cylindrical distal portion 522 of the knuckle 510, to a narrower or smaller portion 562b that is co-axially located with the center lumen 518 of the knuckle 510.

[0146] Now referring to FIGS. 22-23 and 27-28, the proximal portion 561a of the housing 560 also defines a pair of parallel pinholes 563 located distally from the proximal end 560a of the proximal portion 561a. The pair of pinholes 563 are aligned off-center, such that each of the pair of pinholes 563 creates a single passageway through the proximal portion 561a to extend into and through the larger cylindrical portion 562a of the longitudinal passageway 562. Each hole 563 is sized to accept a pin 586 therein to cause a friction or interference fit of the pin 586 within the pinhole 563. Each of the pair of the pinholes 563 is located to position the pins 586 with the circular channel 520 of the knuckle 510. As a result, the clip cartridge 550 is longitudinally restrained to the knuckle 510 by the pins 586, while allowing the clip cartridge 550 to rotate about the knuckle 510.

[0147] As seen in FIG. 28, the distal portion 561b of the housing 560 is a semi-cylindrical structure that extends distally from a perpendicular surface 564 of the proximal portion 561a. With reference to FIG. 28, the semi-cylindrical distal portion 561b has a pair of horizontal walls 565 that extend partially along the distal portion 561b, a first recessed surface 567, and a second recessed surface 568 that define a longitudinally extending recess 566 along the distal portion 561b of the housing 560, between the pair of horizontal walls 565. A pair of inward projection locks 569 extend into the longitudinally extending recess 566 along the first recessed surface 567 with one projection lock extending inward from each of the horizontal walls 565. A spring slot 570 is defined longitudinally along the second recessed surface 568 at a location distal of spring slot 570. A horizontal recess 571 is defined radially along the second recessed surface 568 at a location distal of spring slot 570. Two stops 572 project from the second recess surface 568 along the distal end 560b and define a pair of longitudinal openings 574a, 574b between the horizontal walls 565 and the stops 572, and a distal opening 573 between the two stops 572. The distal portion 561b of the housing 560 is shaped and sized to mate with the cover 590.

[0148] As shown in FIG. 27, the clip cartridge 550 includes a plurality or series of clips or fasteners 580, a cam spring 600, a cam plate 610, a jaw structure 620, a block member 640, a feed bar 650, a clip carrier 660, a clip follower 670, and a follower spring 680, between the housing 560 and the cover 590.

[0149] The plurality of surgical clips 580 are retained within the clip cartridge 550 for application to tissue. As shown in FIG. 27A, each clip 580 has a pair of legs 582a, 582b extending from a backspan 581 and defines a clip axis ‘W’ extending substantially parallel with the pair of legs 582a, 582b. The clips 580 are located adjacent to one another to form an angled stack. With reference to FIGS. 42 and 43, the series of fasteners or clips 580 are arranged within the clip cartridge 550 to form an angle of between, but not including, 0° and 90° with the second longitudinal ‘X2’ axis. The series of clips 580 are stacked in or at an angle with respect to the second longitudinal ‘X2’ axis and extend along in an offset parallel fashion with the second longitudinal ‘X2’ axis. The shape of the clip 580 may be U-shaped, V-shaped, or some other shape.

[0150] As seen in FIGS. 48-51, clip cartridge 550 includes a jaw closure mechanism 532 including the camming plate 610, which is connected with the drive assembly 220 through the block member 640 to provide an approximating force to the jaw structure 620.

[0151] With reference to FIGS. 27 and 29, the cam plate 610 defines a proximal portion 610c and a camming or distal portion 610d. A dog bone shaped aperture 611 is defined in the proximal portion 610c and a camming aperture 614 is defined in the camming portion 610d. The cam plate 610 has a finger 612 that extends perpendicularly to a top/bottom surface thereof and a pair of stops 613 extending outward from the camming portion 610c along a side edge thereof.

[0152] The camming aperture 614 is substantially “V” shaped. The “V” shaped camming aperture 614 defines a protrusion or separator 615 extending into the center of the aperture and a pair of camming surfaces 616 along the outer edges of the aperture. With reference to FIGS. 30 and 49-51, the camming aperture 614 mates with a pair of posts 621 that extend vertically from the jaw structure 620. Each post 621 includes a head 622 that acts to secure the cam plate 610 and the jaw structure 620 together to maintain contact between the two components.

[0153] With reference to FIG. 37, cam plate 610 is located along the second recessed surface 568 of housing 560. The stops 613 of cam plate 610 extend radially outward through the longitudinal openings 574a, 574b of housing 560 to limit longitudinal movement of the cam plate 610 to the length of openings 574a, 574b. The proximal portion 610c of the cam plate 610 is sized to fit into the longitudinal extending recess 566 of the housing 560. When cam plate 610 is at a distal-most position relative to housing 560, a gap 575 is formed between the proximal end 610a of the cam plate 610 and the second recessed surface 567. The finger 612 is sized to be positioned within the spring slot 570 (FIG. 28) of the housing 560. In use, longitudinal movement of the camming plate 610 moves the cam aperture 614 relative to the posts 621 of jaw structure 620.

[0154] With reference to FIG. 38, a cam spring 600 is located within the spring slot 570 of the housing 560 such that the finger 612 of the cam plate 610 is disposed distal of cam spring 600.

[0155] With reference to FIGS. 27 and 30, the jaw structure 620 includes a locking tab 623, a pair of legs 625, and a pair of jaws 626. A pair of lock recesses 628 is defined between the locking tab 623 and the pair of legs 625. The lock recesses 628 extend inward from side edges thereof to form a pair of locking shoulders 624. With reference to FIG. 36, the locking recesses 628 act to secure the jaw structure 620 along the first recessed surface 567 of the housing 560, by providing space for the inward projecting locks 569. The inward projecting locks 569 act upon the locking block 623 and the locking shoulders 624 to prevent longitudinal movement of the jaw structure 620 with respect to the housing 560.

[0156] Each of the pair of legs 625 extends proximally from the respective locking shoulder 624 parallel with the second longitudinal ‘X2’ axis. The pair of jaws 626 is formed at the distal ends of the legs 625 and includes a first jaw 626a and a second jaw 626b. Each jaw 626 extends at an angle from the respective leg 635 to form an angle with the second longitudinal ‘X2’ axis. The clip axis ‘W’ of each clip 580 is substantially parallel to a longitudinal axis of each of the first and second jaws 526a, 526b. Each jaw 626 defines a channel 627 along an inner section that is sized to accept a portion of the clip leg 582a, 582b therein. One of the clip legs 582a, 582b is retained in the channel 627 of the first jaw 626a and the other clip leg 582a, 582b is retained in the channel 627 of the second jaw 626b.

[0157] The jaw assembly or structure 620 is supported on and extends distally from between the cover 590 and the housing 560. The jaw structure 620 includes a first jaw 626a and a second jaw 626b that are moveable between a spaced apart position and an approximated position.

[0158] Referring to FIGS. 27 and 31, the movement of the cam plate 614 is provided by the block member 640. With reference to FIG. 31, the block member 640 includes a pair of rails 644 extending from a surface thereof, and a finger 642 extending from a surface opposite rails 644 at a location proximate a distal end 640b of the block member 640. The finger 642 is sized to extend between the jaw legs 624, 625 and into the dog bone shaped aperture 611 of the camming plate 610.

[0159] With reference to FIGS. 31 and 44-45, a proximal end 640a of the block member 640 is connected with the distal end 224b of the drive cable 224. As a result, advancement or retraction of the drive cable 224 advances or retracts, respectively, the block member 640 along the second longitudinal ‘X2’ axis. Proximal movement or retraction of the block member 640 will cause the finger 642 thereof to abut a proximal end 611a of the dog bone shaped aperture 611 of camming plate 610 and will in turn pull the camming plate 610 proximally. In a proximal position, as seen in FIGS. 49 and 50, the cam aperture 614 presents the separator 615 of camming plate 610, having a tapered end 615a, between the posts 621 of jaw structure 620 to separate the posts 621 and to open the jaws 626.

[0160] Meanwhile, distal movement or advancement of the block member 640 will cause the finger 642 to abut a distal end 611b of the dog bone shaped aperture 611 of camming plate 610 and will in turn push the camming plate 610 distally. In a distal position, as seen in FIG. 51, the camming surfaces 616, of cam aperture 614 of camming plate 610, force the posts 621 of the jaw structure 620 together to close the jaws 626. A longitudinal length of the finger 642 is less than a length of the dog bone shaped aperture 611 to thereby allow the finger 642 of block member 640 to move a predetermined distance before engaging and moving the camming plate 610.

[0161] With reference to FIGS. 27 and 32, a feed bar 650 is provided for longitudinal movement relative to cover 590 in order to advance individual clips 580 into jaws 626. As seen in FIG. 32, to facilitate the insertion of the clip 580 into jaws 626, feed bar 650 is provided with the pusher 652 at its distal end 650b, which is configured to advance an individual clip 580 out of the stack of clips 580 and into jaws 626.

[0162] The pusher 652 is sized and shaped to selectively engage/move (i.e., distally advance) a distal-most clip “C1” (FIGS. 42 and 43) of the clips 580 into the jaws 626. The feed bar defines a pair of recess 654a, 654b along each side edge thereof that are sized and shaped to accept the rails 644a, 644b of the block member 640 to mate the feed bar 650 and the block member 640. Turning to FIGS. 44-48, it is understood that a movement of the block member 640 causes a movement of the feed bar 650 in the same direction and in the same magnitude.

[0163] With reference to FIGS. 27 and 39-41, the feed bar 650 is slidably disposed under the clip carrier 660. The clip carrier 660 is shaped and sized to retain the plurality of surgical clips 580 thereon. It should be noted that clip carrier 660 and jaw structure 620 do not move longitudinally relative to housing 560.

[0164] Referring to FIG. 33, the clip carrier 660 includes a distal pair of slots 664 sized and shaped to receive the pusher 652 of feed bar 650 therein. The clip carrier 660 is formed with a ‘hat’ shaped transverse cross-sectional profile, consisting of a center platform 667, two vertical walls 666 projecting downward from the center platform 667, and a horizontal wall 665 projecting outward from each of the vertical walls 666. Each of the horizontal walls 665 includes two longitudinally spaced retainers 661 that project upward along an outside edge. Each of the retainers 661 defines an opening 662 therethrough. A ramp section 668 about a distal end 660b allows the center platform 667 to be shorter than the horizontal walls 665.

[0165] As shown in FIG. 40, a proximal end 660a of the clip carrier 660 is located against the perpendicular surface 564 of the housing 560 and the horizontal walls 665 sit upon the horizontal walls 565 of the housing 560. The ramp section 668 extends the clip carrier 660 partially over a flared out section 629 of the legs 625 of the jaw structure 620. The ramp section 668 forms substantially the same angle with respect to the second longitudinal ‘X2’ axis as the jaws 626.

[0166] With reference to FIGS. 27, 34, and 40, the clip follower 670 sits on top of the clip carrier 660. As shown in FIG. 34, the clip follower 670 includes an abutment surface 672 for engagement with the stack of clips 580 and includes two aims 674a, 674b for engagement about the clip carrier 660. The clip follower 670 includes a proximally extending post 676 sized to fit inside of follower spring 680. With reference to FIG. 42, the clip follower 670 is positioned behind the stack of clips 580 on the clip carrier 660 to advance the stack of clips 580 through surgical clip applier 100 as the distal-most clip is fired.

[0167] The clip follower 670 is biased distally by the follower spring 680 to urge the stack of clips 580 distally along the clip carrier 660. The cover 590 overlies the clip carrier 660 and is configured to retain and guide advancement of the follower 670, the follower spring 680, and the stack of clips 580 therein.

[0168] As seen in FIGS. 27 and 35, the cover 590 of clip cartridge 550 has a substantially semi-cylindrical body 591 and a nose 592. Two pairs of securing protrusions 593 extend radially outward along each side of the semi-cylindrical body 591 of cover 590. Each securing protrusion 593 is sized and shaped to fit into and project through the openings 662 in the retainers 661 of the clip carrier 660. The cover 590 defines a longitudinal passage 595 therealong.

[0169] With reference to FIG. 45, the clip carrier 660 forms an elongated clip channel with the inner surface of the longitudinal passage 595 of the cover 590 for retaining the plurality of clips 580, as shown in stacked manner above the clip carrier 660 in FIGS. 40-43. To direct the clips 580 traversing along the clip channel and into the jaws 626, a ramped inner surface 596 is provided at a distal end 590b of cover 590 along the nose 592 to assist in directing surgical clips 580 into jaws 626. The proximal end 590a of cover 590 is shaped to abut the perpendicular surface 564 of the housing 560.

[0170] With reference to FIGS. 44-48, the operation of the clip cartridge 550 will now be discussed. Initially, jaws 626 are placed about a vessel “V.” As seen in FIG. 44, actuation of the trigger 208 (see FIG. 5A) causes distal movement of the drive assembly 220 (see FIG. 5A) and drive rod 222, represented by the direction arrow ‘a’. The distal movement of drive rod 222 causes distal advancement of drive cable 224 which in turn causes the advancement of the block member 640, represented by the direction arrow ‘b’. Referring to FIG. 45, the distal movement of the block member 640 causes a distal advancement of the feed bar 650, represented by the direction arrow ‘c’. As the block member 640 is moved distally, the finger 642 thereof abuts against a reduced width portion of the dog bone shaped recess 611 to force the feed bar 650 distally. As the feed bar 650 is advanced distally, the pusher 652 of feed bar 650 forces a distal-most clip ‘C1’ distally and in-between the jaw members 626, as illustrated by the direction arrow ‘d’ in FIG. 46. During a further advancement of the block member 640, the finger 642 of the block member 640 travels along the dog bone shaped recess 611 of the cam plate 610 thereby maintaining the cam plate 610 stationary in a distal-most position, as seen in FIGS. 40 and 50.

[0171] Referring to FIGS. 47 and 48, with distal-most clip “C1” loaded in jaw members 626, retraction of the drive rod 222 as a result of a release of trigger 208, represented by the direction arrow ‘g’, causes a retraction or a proximal movement of the block member 640 and of the pusher 652 of feed bar 650, as illustrated by direction arrow ‘e’. As the feed bar 650 is returned to the initial or starting position, the pusher 652 is forced down toward the center of the clip cartridge 550 by a ramped edge 653 of the pusher 652 riding across the next clip in the stack of clips 580. Referring to FIG. 48, the ramped edge 653 also allows the pusher 652 to be positioned under the clip carrier 660, while the block member 640 continues to move proximally from the initial starting position, represented by the direction arrow ‘h’. As the block member 640 moves proximally from the initial starting position, the finger 642 abuts and acts against the reduced width portion of the dog bone shaped recess 611 to force the cam plate 610 to move proximally, represented by the direction arrow ‘i’. As the cam plate 610 moves proximally, the finger 612 of the cam plate 610 moves proximally, represented by direction arrow ‘j’ to compress the cam spring 600, represented by the direction arrow ‘k’.

[0172] With reference to FIGS. 49-52, the forming of the clip ‘C1” about a blood vessel will now be discussed. The interconnected cam plate 610 and jaw structure 626, as discussed earlier is shown in FIG. 49. With the jaws 626, having a clip ‘C1’ loaded therein and being placed about the blood vessel, the cam plate 610 is forced proximally by the proximally moving block member 640 to cause the camming surface 616 (see FIG. 27) of jaws 626 to act against the posts 621 of the jaw structure 626. As the camming surface 616 of camming aperture 614 abuts each of the posts 621 of the jaw structure 626, the posts 621 are forced together to form the clip ‘C1’ about the blood vessel, as illustrated in FIG. 52.

[0173] As the trigger 208 continues to open to withdraw drive rod 222, block member 640 is further pulled in the proximal direction until finger 642 thereof is pulled through the reduced width portion of the dog bone shaped recess 611 of the cam plate 610 at which time cam spring 600 is permitted to expand and act on finger 612 of cam plate 610 to move cam plate 610 distally and open jaw structure 626.

[0174] In this manner, a single complete stroke of trigger 208 results in a feeding of a clip “C1” into the jaws 626 and a forming of the loaded clip by the jaws 626. Such a firing sequence can be accomplished with the second longitudinal axis “X2” of the end effector 500 either axially aligned with or angled with respect to the first longitudinal axis “X1” of the first tubular member 302 of the shaft assembly 300.

[0175] It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications, and variances. The embodiments described with reference to the attached drawing figures are presented only to demonstrate certain examples of the disclosure. Other elements, steps, methods, and techniques that are insubstantially different from those described above and/or in the appended claims are also intended to be within the scope of the disclosure.