Patent Publication Number: US-2021169468-A1

Title: Endoscopic stitching devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation Application of U.S. patent application Ser. No. 16/211,398, filed Dec. 6, 2018, which is a Continuation Application of U.S. patent application Ser. No. 15/372,616, filed Dec. 8, 2016, now U.S. Pat. No. 10,413,289, which is a Continuation Application of U.S. patent application Ser. No. 12/896,364, filed on Oct. 1, 2010, now abandoned, which claims the benefit of and priority to each of U.S. Provisional Application Ser. No. 61/304,825, filed on Feb. 16, 2010, and U.S. Provisional Application Ser. No. 61/249,063, filed on Oct. 6, 2009, the entire contents of each of which are incorporated herein by reference. 
     U.S. patent application Ser. No. 12/896,364 is also a Continuation-in-Part Application of U.S. patent application Ser. No. 12/482,049, filed Jun. 10, 2009, now U.S. Pat. No. 8,628,545, which claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/061,136, filed Jun. 13, 2008, the entire contents of each of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to devices, systems and methods for endoscopic suturing or stitching and, more particularly, to devices, systems and methods for endoscopic suturing and/or stitching through an access tube or the like. 
     Background 
     As medical and hospital costs continue to increase, surgeons are constantly striving to develop advanced surgical techniques. Advances in the surgical field are often related to the development of operative techniques which involve less invasive surgical procedures and reduce overall patient trauma. In this manner, the length of hospital stays can be significantly reduced, and, therefore, the hospital and medical costs can be reduced as well. 
     One of the truly great advances in recent years to reduce the invasiveness of surgical procedures is endoscopic surgery. Generally, endoscopic surgery involves incising through body walls for example, viewing and/or operating on the ovaries, uterus, gall bladder, bowels, kidneys, appendix, etc. There are many common endoscopic surgical procedures, including arthroscopy, laparoscopy (pelviscopy), gastroentroscopy and laryngobronchoscopy, just to name a few. Typically, trocars are utilized for creating the incisions through which the endoscopic surgery is performed. Trocar tubes or cannula devices are extended into and left in place in the abdominal wall to provide access for endoscopic surgical tools. A camera or endoscope is inserted through a relatively large diameter trocar tube which is generally located at the naval incision, and permits the visual inspection and magnification of the body cavity. The surgeon can then perform diagnostic and therapeutic procedures at the surgical site with the aid of specialized instrumentation, such as, forceps, cutters, applicators, and the like which are designed to fit through additional cannulas. Thus, instead of a large incision (typically 12 inches or larger) that cuts through major muscles, patients undergoing endoscopic surgery receive more cosmetically appealing incisions, between 5 and 10 millimeters in size. Recovery is, therefore, much quicker and patients require less anesthesia than traditional surgery. In addition, because the surgical field is greatly magnified, surgeons are better able to dissect blood vessels and control blood loss. Heat and water loss are greatly reduced as a result of the smaller incisions. 
     In many surgical procedures, including those involved in endoscopic surgery, it is often necessary to suture bodily organs or tissue. The latter is especially challenging during endoscopic surgery because of the small openings through which the suturing of bodily organs or tissues must be accomplished. 
     In the past, suturing of bodily organs or tissue through endoscopic surgery was achieved through the use of a sharp metal suture needle which had attached at one of its ends a length of suture material. The surgeon would cause the suture needle to penetrate and pass through bodily tissue, pulling the suture material through the bodily tissue. Once the suture material was pulled through the bodily tissue, the surgeon proceeded to tie a knot in the suture material. The knotting of the suture material allowed the surgeon to adjust the tension on the suture material to accommodate the particular tissue being sutured and control approximation, occlusion, attachment or other conditions of the tissue. The ability to control tension is extremely important to the surgeon regardless of the type of surgical procedure being performed. 
     However, during endoscopic surgery, knotting of the suture material is time consuming and burdensome due to the difficult maneuvers and manipulation which are required through the small endoscopic openings. 
     Many attempts have been made to provide devices to overcome the disadvantages of conventional suturing. Such prior art devices have essentially been staples, clips, clamps or other fasteners. However, none of these above listed devices overcome the disadvantages associated with suturing bodily tissue during endoscopic surgery. 
     Accordingly, there is a need for improvements in suturing devices which overcome the shortcomings and drawbacks of prior art apparatus. 
     SUMMARY 
     An endoscopic stitching device consistent with the present invention comprises a handle assembly; an elongate shaft supported by and extending from the handle assembly; and an end effector supported on a distal end of the elongate shaft, the end effector including a neck assembly configured and adapted for articulation in one direction between a substantially linear configuration and an off-axis configuration, and a pair of juxtaposed jaws pivotally associated with one another, wherein each jaw defines a suture needle receiving recess formed in a tissue contacting surface thereof. 
     In one embodiment, the jaws that are rotatably supported on the end effector for selective rotation about a longitudinal axis thereof when the end effector is in the substantially linear configuration and in the articulated configuration. In another embodiment, the handle assembly supports a rotation assembly configured to transmit an actuation from the handle assembly through the elongate shaft to effectuate rotation of the jaws. The rotation assembly may include a knob rotatably supported on a housing of the handle assembly and operatively connected to a center drive rod assembly, wherein the center drive rod assembly includes a distal end extending through the elongate shaft and connected to the jaws. In some embodiments, at least a portion of the center drive rod assembly is flexible. In an embodiment, the endoscopic stitching device includes a center drive rod assembly translatably supported therein, the center drive rod assembly including a proximal end operatively connected to at least one handle of the handle assembly and a distal end extending through the elongate shaft and operatively connected to the jaws, wherein axial translation of the center drive rod assembly results in opening and closing of the jaws. In an embodiment, the axial rotation of the center drive rod assembly results in rotation of the jaws about a longitudinal axis thereof. In one embodiment, the endoscopic stitching device includes a rotation assembly supported on a housing of the handle assembly and operatively connected to the center drive rod assembly, wherein actuation of the rotation assembly results in concomitant rotation of the center drive rod assembly and the jaws. In an embodiment, at least a portion of a length of the center drive rod assembly is flexible, wherein the flexible portion of the center drive rod assembly will flex upon an articulation of the end effector and enable rotation of the jaws when the end effector is in an articulated condition. 
     In an embodiment, the end effector further includes a pair of axially translatable needle engaging blades slidably supported, one each, in a respective jaw, each blade having a first position wherein a portion of the blade engages a suture needle when a suture needle is present in suture needle receiving recess formed in the tissue contacting surface of the jaw, and a second position wherein the blade does not engage the suture needle. In accordance with an embodiment, a proximal end of each blade is rotatably supported on a respective barrel of a concentric barrel pair, wherein the blades rotate about the barrels upon a rotation of the jaws. 
     In some embodiments, a suture needle is loadable into the suture needle receiving recess defined in the jaw when the respective blade is in the second position. In one embodiment, the device includes a loading/unloading assembly supported on the handle assembly and connected to each blade, wherein the loading/unloading assembly is movable between a first position in which the blades are in the first position and a second position in which the blades are in the second position. The loading/unloading assembly may be actuatable in a first direction to move a first blade to the first position and a second blade to the second position, and a second direction to move the first blade in the second direction and the second blade in the first direction. 
     An endoscopic stitching device of the present invention may also include an articulation assembly supported on the handle assembly and actuatable to articulate the end effector, wherein actuation of the articulation assembly results in articulation of the end effector between the linear configuration and the off-axis configuration. In one embodiment, the articulation assembly includes an articulation cam supported on a housing of the handle assembly and includes first and second cam disks having opposing respective first and second camming channels defined therein, a first pin operably associated with the first camming channel and a first slider configured to longitudinally translate with respect to the housing, and a second pin operably associated with the second camming channel and a second slider configured to longitudinally translate with respect to the housing, the first and second slider secured with respective proximal ends of first and second articulation cables, the distal ends being secured at a location distal of the neck assembly, and wherein the articulation cables are disposed on opposed sides of a center drive rod assembly. The first and second camming channels may be configured to provide equidistant linear motion directly proportional to the angular rotation of the first and second cam disks. The first and second camming channels may have a shape substantially similar to a logarithmic spiral. In some embodiments, each articulation cable remains substantially taut upon translation thereof. In an embodiment, the first and second cam disks are monolithically formed. A torsion spring may operably couple the first and second cam disks. In some embodiments, the articulation assembly includes an articulation knob supported on a housing of the handle assembly, an articulation sleeve operatively connected to the articulation knob and including a pair of oppositely pitched outer helical threads, an articulation collar threadably connected to each helical thread and configured to permit axial translation and prevent rotation thereof, and an articulation cable secured to each articulation collar, wherein each articulation cable includes a first end secured to the respective articulation collar and a second end secured at a location distal of the neck assembly, and wherein the articulation cables are disposed on opposed sides of a center drive rod assembly. 
     In an embodiment, each articulation cable is operably associated with a seal having first and second lumens extending therethrough, and wherein at least one lumen is configured to receive at least one articulation cable in substantial sealing relationship therewith. At least one of the first and second lumens of the seal may have an arched section. In an embodiment, at least one of the first and second lumens of the seal is repositionable through a plurality of positions including a first position and a second position in response to longitudinal translation of at least one articulation cable therethrough. In an embodiment, at least one lumen of the seal is biased towards at least one of the first or second positions. 
     In some embodiments, rotation of the articulation knob results in rotation of the articulation sleeve and concomitant axial translation of the articulation collars, wherein axial translation of the articulation collars results in articulation of the end effector. In an embodiment, rotation of the articulation sleeve in a first direction results in relative axial separation of the articulation collars to articulate the end effector in a first direction, and rotation of the articulation sleeve in a second direction results in relative axial separation of the articulation collars to articulate the end effector in a second direction. 
     In one embodiment, the neck assembly includes a plurality of links in pivotable contact with one another, wherein each link includes a knuckle formed on a first side thereof and a clevis formed on a second side thereof, wherein the knuckle of a first link is operatively connected to a clevis of an adjacent link. In one embodiment, the neck assembly further includes at least one stiffener plate translatably disposed in the plurality of operatively connected links. In one embodiment, one end of the at least one stiffener plate is securely attached to the neck assembly. The knuckles and devises may be configured to enable uni-directional articulation of the neck assembly. The knuckles and devises may be configured to at least partially overlap one another when the neck assembly is in either the substantially linear configuration or the off-axis configuration. An endoscopic stitching device according to the present invention may include a handle assembly that has a pair of handles and a center drive rod connected at a first end to the handles and at a second end to the pair of jaws, wherein actuation of the handles results in axial translation of the center drive rod and concomitant opening and closing of the jaws. 
     An endoscopic stitching device consistent with an embodiment of the invention includes a handle assembly including a housing; an elongate shaft supported by and extending from the housing; an end effector supported on a distal end of the elongate shaft, the end effector including a neck assembly configured and adapted for articulation in one direction between a substantially linear configuration and an off-axis configuration, and a pair of juxtaposed jaws pivotally associated with one another, wherein each jaw defines a suture needle receiving recess formed in a tissue contacting surface thereof, and wherein the jaws are rotatably supported on the end effector for selective rotation about a longitudinal axis thereof when the end effector is in the substantially linear configuration and in the articulated configuration; an articulation assembly supported on the housing and actuatable to articulate the end effector, wherein actuation of the articulation assembly results in articulation of the end effector between the linear configuration and the off-axis configuration; and a rotation assembly supported on the housing, the rotation assembly being configured to transmit an actuation from the handle assembly through the elongate shaft to effectuate rotation of the jaws. 
     In an embodiment, the articulation assembly includes an articulation cam supported on a housing of the handle assembly and includes first and second cam disks having opposing respective first and second camming channels defined therein, a first pin operably associated with the first camming channel and a first slider configured to longitudinally translate with respect to the housing, and a second pin operably associated with the second camming channel and a second slider configured to longitudinally translate with respect to the housing, the first and second slider secured with respective proximal ends of first and second articulation cables, the distal ends being secured at a location distal of the neck assembly, and wherein the articulation cables are disposed on opposed sides of a center drive rod assembly. The first and second camming channels may be configured to provide equidistant linear motion directly proportional to the angular rotation of the first and second cam disks. The first and second camming channels may have a shape substantially similar to a logarithmic spiral. In some embodiments, each articulation cable remains substantially taut upon translation thereof In an embodiment, the first and second cam disks are monolithically formed. A torsion spring may operably couple the first and second cam disks. 
     In an embodiment, the rotation assembly includes a knob rotatably supported on the housing and operatively connected to a center drive rod assembly, wherein the center drive rod assembly includes a distal end extending through the elongate shaft and connected to the jaws. The rotation assembly may include a beveled gear assembly operatively associated with the knob. The beveled gear assembly may be configured to translate the center drive rod assembly for opening and closing the jaws. The beveled gear assembly may be configured to translate rotational energy to the center drive rod assembly in accordance with at least one of the following ratios 1:1, more than 1:1, or less than 1:1. In an embodiment, the beveled gear assembly includes a sun gear disposed in mechanical cooperation with the knob and operatively associated with first and second beveled gears, the first and second beveled gears being operatively associated with each other. The beveled gear assembly may further include a first beveled gear mount disposed in mechanical cooperation with the first beveled gear and the knob. The second beveled gear may be disposed in mechanical cooperation with the center drive rod assembly. In an embodiment, at least a portion of the center drive rod assembly extending through the neck assembly is flexible. 
     In one embodiment, the endoscopic stitching device includes a center drive rod assembly at least translatably supported in the housing, the elongate shaft and the end effector, and at least rotatably supported in the elongate shaft and the end effector, the center drive rod assembly including a proximal end operatively connected to at least one handle of the handle assembly and a distal end extending through the elongate shaft and operatively connected to the jaws, wherein axial translation of the center drive rod assembly results in opening and closing of the jaws. 
     In one embodiment, axial rotation of at least a distal portion of the center drive rod assembly results in rotation of the jaws about a longitudinal axis thereof. In an embodiment, the end effector further includes a pair of axially translatable needle engaging blades slidably supported, one each, in a respective jaw, each blade having a first position wherein a portion of the blade engages a suture needle when a suture needle is present in suture needle receiving recess fanned in the tissue contacting surface of the jaw, and a second position wherein the blade does not engage the suture needle. A proximal end of each blade may be rotatably supported on a respective barrel of a concentric barrel pair, wherein the blades rotated about the barrels upon a rotation of the jaws. A suture needle may be loadable into the suture needle receiving recess defined in the jaw when the respective blade is in the second position. 
     An endoscopic stitching device consistent with invention may have a loading/unloading assembly supported on the handle assembly and connected to each blade, wherein the loading/unloading assembly is movable between a first position in which the blades are in the first position and a second position in which the blades are in the second position. The loading/unloading assembly may be actuatable in a first direction to move a first blade to the first position and a second blade to the second position, and a second direction to move the first blade in the second direction and the second blade in the first direction. 
     In an embodiment, the articulation assembly includes an articulation knob supported on the housing of the handle assembly, an articulation sleeve operatively connected to the articulation knob and including a pair of oppositely pitched outer helical threads, an articulation collar threadably connected to each helical thread and configured to permit axial translation and prevent rotation thereof, and an articulation cable secured to each articulation collar, wherein each articulation cable includes a first end secured to the respective articulation collar and a second end secured at a location distal of the neck assembly, and wherein the articulation cables are disposed on opposed sides of a center drive rod assembly. 
     In an embodiment, each articulation cable is operably associated with a seal having first and second lumens extending therethrough, and wherein at least one lumen is configured to receive at least one articulation cable in substantial sealing relationship therewith. At least one of the first and second lumens of the seal may have an arched section. At least one of the first and second lumens of the seal may be repositionable through a plurality of positions including a first position and a second position in response to longitudinal translation of at least one articulation cable therethrough. In an embodiment, at least one lumen of the seal is biased towards at least one of the first or second positions. 
     In an embodiment, rotation of the articulation knob results in rotation of the articulation sleeve and concomitant axial translation of the articulation collars, wherein axial translation of the articulation collars results in articulation of the end effector. In one embodiment, rotation of the articulation sleeve in a first direction results in relative axial separation of the articulation collars to articulate the end effector in a first direction, and rotation of the articulation sleeve in a second direction results in relative axial separation of the articulation collars to articulate the end effector in a second direction. 
     An endoscopic stitching device of the invention may have a neck assembly that includes a plurality of links in pivotable contact with one another, wherein each link includes a knuckle formed on a first side thereof and a clevis formed on a second side thereof, wherein the knuckle of a first link is operatively connected to a clevis of an adjacent link. The neck assembly may further include at least one stiffener plate translatably disposed in the plurality of operatively connected links. One end of the at least one stiffener plate may be securely attached to the neck assembly. The knuckles and devises may be configured to enable uni-directional articulation of the neck assembly. The knuckles and devises may be configured to at least partially overlap one another when the neck assembly is in either the substantially linear configuration or the off-axis configuration. 
     In an embodiment, the handle assembly includes a pair of handles supported on the housing; and a center drive rod connected at a first end to the handles and at a second end to the pair of jaws, wherein actuation of the handles results in axial translation of the center drive rod and concomitant opening and closing of the jaws. 
     An endoscopic stitching device consistent with an embodiment of the invention includes a handle assembly; an elongate shaft supported by and extending from the handle assembly; an end effector supported on a distal end of the elongate shaft, the end effector including a neck assembly configured and adapted for articulation in one direction between a substantially linear configuration and an off-axis configuration, and a pair of juxtaposed jaws pivotally associated with one another; and a stiffener plate disposed in the neck assembly and axially extending therein, wherein the stiffener plate defines a plane. 
     In an embodiment, the plane defined by the stiffener plate is substantially orthogonal to a direction of articulation. The stiffener plate may be substantially flat, wherein the substantially flat stiffener plate is bendable in one direction. The stiffener plate may be translatably disposed in the neck assembly. The end effector may be articulatable in a direction out of the plane defined by the stiffener plate. In an embodiment, the stiffener plate restricts planar articulation of the end effector with respect to the plane defined by the stiffener plate. In one embodiment one end of the stiffener plate includes an anchor portion secured to the neck assembly, wherein the anchor portion may be bifurcated, the bifurcated anchor portion including at least a pair of spaced apart tines. In an embodiment, a free end of the stiffener plate is axially tapered with respect to the width thereof. In some embodiments, the free end of the stiffener plate may be axially tapered with respect to the thickness thereof. In one embodiment, the neck assembly includes a plurality of links in pivotable contact with one another, wherein each link defines a stiffener plate receiving slot for receiving the stiffener plate therethrough. The stiffener plate may extend through the slot of at least one of the links. The stiffener plate, however, may also extend through the slot of all of the links. The stiffener plate may be made of resilient material. 
     An endoscopic stitching device consistent with an embodiment of the invention includes a handle assembly; an elongate shaft supported by and extending from the handle assembly; an end effector supported on a distal end of the elongate shaft, the end effector including a neck assembly configured and adapted for articulation in one direction between a substantially linear configuration and an off-axis configuration, and a pair of juxtaposed jaws pivotally associated with one another; and a pair of stiffener plates disposed in the neck assembly and axially extending therein, wherein each of the pair of stiffener plates defines a plane. 
     In one embodiment, the pair of stiffener plates is substantially parallel with one another. The plane defined by each of the pair of stiffener plates may be substantially orthogonal to a direction of articulation. In an embodiment, the pair of stiffener plates is substantially flat, wherein the pair of substantially flat stiffener plates is bendable in one direction. In an embodiment, the pair of stiffener plates is translatably disposed in the neck assembly, wherein the end effector is articulatable in a direction out of the plane defined by the pair of stiffener plates. In one embodiment, the pair of stiffener plates restricts planar articulation of the end effector with respect to the planes defined by the pair of stiffener plates. One end of each of the pair of stiffener plates may include an anchor portion secured to the neck assembly. The anchor portion may be bifurcated, each of the bifurcated anchor portion including at least a pair of spaced apart tines. In an embodiment, a free end of the respective stiffener plate is axially tapered with respect to the width thereof. In another embodiment, a free end of the respective stiffener plate is axially tapered with respect to the thickness thereof. In one embodiment, the neck assembly includes a plurality of links in pivotable contact with one another, wherein each link defines a pair of stiffener plate receiving slots tor receiving the stiffener plates therethrough. The pair of stiffener plates may extend through the slot of at least one of the links. The pair of stiffener plates may also extend through the slot of all of the links. The stiffener plate may be made of resilient material. 
    
    
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
       The foregoing objects, features and advantages of the disclosure will become more apparent from a reading of the following description in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a flexible stitching device according to an embodiment of the present disclosure; 
         FIG. 2  is a top, plan view of the flexible stitching device of  FIG. 1 ; 
         FIG. 3  is a side, elevational view of the flexible stitching device of  FIGS. 1 and 2 ; 
         FIG. 4  is a perspective view of an end effector of the flexible stitching device of  FIGS. 1-3 ; 
         FIG. 5  is a perspective view of a neck assembly of the flexible stitching device of  FIGS. 1-3 ; 
         FIG. 6  is a perspective view of the neck assembly of  FIG. 5 , as viewed along line  6 - 6  of  FIG. 5 ; 
         FIG. 7  is a top, right-side, perspective view of a handle assembly of the flexible stitching device, illustrated with a housing half-section removed therefrom; 
         FIG. 8  is a top, left-side, perspective view of a handle assembly of the flexible stitching device, illustrated with a housing half-section removed therefrom; 
         FIG. 9  is a perspective view, with parts separated, of the flexible stitching device; 
         FIG. 10  is a perspective view, with parts separated, of a needle load assembly and an end effector articulation assembly of the flexible stitching device; 
         FIG. 11  is a perspective view of a suture needle assembly of the present disclosure; 
         FIG. 12  is a perspective view, with parts separated, of a needle retention assembly of the flexible stitching device; 
         FIG. 13  is a perspective view, with parts assembled, of the needle retention assembly of  FIG. 12 ; 
         FIG. 14  is a longitudinal, cross-sectional view of the needle retention assembly of  FIGS. 12 and 13 , as taken through  14 - 14  of  FIG. 13 ; 
         FIG. 15  is a longitudinal, cross-sectional view of the flexible stitching device of the present disclosure, as taken through  15 - 15  of  FIG. 3 ; 
         FIG. 16  is a longitudinal, cross-sectional view of the flexible stitching device of the present disclosure, as taken through  16 - 16  of  FIG. 15 ; 
         FIG. 17  is an enlarged view of the indicated area of detail of  FIG. 15 ; 
         FIG. 18  is an enlarged view of the indicated area of detail of  FIG. 16 ; 
         FIG. 19  is an enlarged view of the indicated area of detail of  FIG. 15 ; 
         FIG. 20  is an enlarged view of the indicated area of detail of  FIG. 16 ; 
         FIG. 21  is a cross-sectional view of the handle assembly, as taken through  21 - 21  of  FIG. 20 ; 
         FIG. 22  is a cross-sectional view of a jaw of the end effector assembly, as taken through  22 - 22  of  FIG. 17 ; 
         FIG. 23  is a cross-sectional view of the handle assembly, of the flexible stitching device, illustrating an initial actuation of the handles thereof; 
         FIG. 24  is a cross-sectional view of the end effector assembly, of the flexible stitching device, during the initial actuation of the handle assembly; 
         FIG. 25  is an enlarged view of the indicated area of detail of  FIG. 24 : 
         FIG. 26  is a cross-sectional view of the jaw of the end effector illustrating the needle of the suture needle assembly disposed therein; 
         FIG. 27  is a cross-sectional view illustrating the movement of the needle load assembly during the initial actuation of the handle assembly; 
         FIG. 28  is a cross-sectional view of the needle load assembly of  FIG. 27  as taken through  28 - 28  of  FIG. 27 ; 
         FIG. 29  is a perspective view of a housing half-section of the flexible stitching device; 
         FIG. 30  is an enlarged view of the indicated area of detail of  FIG. 29 ; 
         FIG. 31  is a cross-sectional view of the handle assembly, of the flexible stitching device, illustrating a release of handles thereof and an actuation of a needle retention assembly; 
         FIG. 32  is a plan view further illustrating the actuation of the needle retention assembly; 
         FIG. 33  is a longitudinal, cross-sectional view of the end effector assembly, illustrating the loading of a suture needle assembly therein; 
         FIG. 34  is a cross-sectional view of the end effector assembly as taken through  34 - 34  of  FIG. 33 ; 
         FIG. 35  is a cross-sectional view of the end effector assembly as taken through  35 - 35  of  FIG. 33 ; 
         FIG. 36  is a cross-sectional view of the handle assembly, of the flexible stitching device, illustrating a further actuation of the needle retention assembly; 
         FIG. 37  is a longitudinal, cross-sectional view of the end effector assembly, illustrating the positioning of the needle of the suture needle assembly in an opposite jaw thereof; 
         FIG. 38  is a cross-sectional view of the handle assembly as taken through  38 - 38  of  FIG. 8 ; 
         FIG. 39  is a cross-sectional view of the handle assembly as taken through  39 - 39  of  FIG. 8 ; 
         FIG. 40  is a longitudinal cross-sectional view of the handle assembly, illustrating an actuation of the articulation assembly; 
         FIG. 41  is a perspective view, with parts separated, of the neck assembly of the flexible stitching device; 
         FIG. 42  is a perspective view of a link of the neck assembly of  FIG. 41 ; 
         FIG. 43  is a cross-sectional view of the end effector, illustrating an articulation thereof; 
         FIG. 44  is a perspective view of the end effector of  FIG. 43 ; 
         FIG. 45  is a cross-sectional view of the handle assembly as taken through  45 - 45  of  FIG. 7 , illustrating an operation of a rotation assembly of the flexible stitching device; 
         FIG. 46  is a cross-sectional view of the handle assembly as taken through  46 - 46  of  FIG. 7 , illustrating a further operation of a rotation assembly of the flexible stitching device; 
         FIG. 47  is a perspective view illustrating the connection of a distal center rod and a proximal center rod, including a coupling sleeve; 
         FIG. 48  is a perspective view illustrating the connection of the distal center rod and the proximal center rod, with the coupling sleeve removed therefrom; 
         FIG. 49  is a perspective view, with parts separated, of the connection of a distal link of the neck portion of the end effector assembly to a distal support member of the end effector assembly; 
         FIG. 50  is an enlarged view of the indicated area of detail of  FIG. 49 ; 
         FIG. 51  is a longitudinal cross-sectional view illustrating the connection of the distal link of the neck assembly the distal support member; 
         FIG. 52  is an enlarged view of the indicated area of detail of  FIG. 51 ; 
         FIG. 53  is a perspective view of the end effector assembly, illustrating a rotation thereof; 
         FIG. 54  is a front, perspective view of an end effector rotation assembly according to another embodiment of the present disclosure; 
         FIG. 55  is a rear, perspective view of the end effector rotation assembly of  FIG. 54 ; 
         FIG. 56  is a perspective view, with parts separated, of the end effector rotation assembly of  FIGS. 54 and 55 ; 
         FIG. 57  is a rear, perspective view of the end effector rotation assembly of  FIGS. 54-56 , illustrating an operation thereof; 
         FIG. 58  is a front, perspective view of an end effector rotation assembly according to still another embodiment of the present disclosure; 
         FIG. 59  is a cross-sectional view of the end effector rotation assembly of  FIG. 58 , as taken through  59 - 59  of  FIG. 58 ; 
         FIG. 60  is a perspective view, with parts separated, of the end effector rotation assembly of  FIGS. 58 and 59 ; 
         FIG. 61  is a cross-sectional view of the end effector rotation assembly of  FIGS. 58-60 , as taken through  61 - 61  of  FIG. 58 ; 
         FIG. 62  is the cross-sectional view of  FIG. 59 , illustrating an operation of the end effector rotation assembly of  FIGS. 58-61 ; 
         FIG. 63  is a longitudinal, cross-sectional view of another embodiment of the distal end of a flexible stitching device of the present disclosure, including an arched seal therein; 
         FIG. 64  is an enlarged view of the indicated area of detail of  FIG. 63 , with the arched seal being illustrated in a first position; 
         FIG. 65  is a perspective view of the arched seal of  FIG. 63 ; 
         FIG. 66  is a perspective, longitudinal, cross-sectional view of the arched seal of  FIGS. 63-65 , as taken through  66 - 66  of  FIG. 65 ; 
         FIG. 67  is a transverse, cross-sectional view of the arched seal of  FIGS. 63-66 , as taken through  67 - 67  of  FIG. 64 ; 
         FIG. 68  is a longitudinal, cross-sectional view of the arched seal of  FIGS. 63-67 , with the arched seal being illustrated in a second position; 
         FIG. 69  is a transverse, cross-sectional view of the arched seal of  FIGS. 63-68 , as taken through  69 - 69  of  FIG. 68 ; 
         FIG. 70  is a longitudinal, cross-sectional view of an end effector rotation assembly according to another embodiment of the present disclosure; 
         FIG. 71  is a perspective view of a gear assembly of the end effector rotation assembly of  FIG. 70 ; 
         FIG. 72  is a cross-sectional view of the end effector rotation assembly of  FIGS. 70 and 71 , as taken through  72 - 72  of  FIG. 70 ; 
         FIG. 73  is a perspective view of another embodiment of a handle assembly of the flexible stitching device, including another embodiment of an articulation assembly therein; 
         FIG. 74  is an enlarged perspective view of the handle assembly of  FIG. 73  with the housing removed to illustrate the articulation assembly; 
         FIG. 75  is a perspective view, with parts separated, of the articulation assembly of  FIGS. 73-74 ; 
         FIG. 76  is a side elevational view of an articulation cam of the articulation assembly of  FIGS. 73-75 , with the articulation cam being illustrated in a first position; 
         FIG. 77  is a side elevational view of the articulation cam of  FIG. 76  with the articulation cam being illustrated in a second position; 
         FIG. 78  is a side elevational view of the articulation cam of  FIGS. 76-77  with the articulation cam being illustrated in a third position; 
         FIG. 79  is a perspective view of another embodiment of an articulation cam in accordance with the present disclosure; 
         FIG. 80  is a top plan schematic view of another embodiment of an articulation assembly in accordance with the present disclosure; 
         FIG. 81  is a top plan schematic view of another embodiment of an articulation assembly in accordance with the present disclosure; 
         FIG. 82  is a side elevational schematic view of another embodiment of an articulation assembly in accordance with the present disclosure; 
         FIG. 83  is a perspective, longitudinal, cross-sectional view of another embodiment of the neck assembly in accordance with the present disclosure, incorporating therein two stiffener plates; 
         FIG. 84A  is a distal end view of a stem of the neck assembly of  FIG. 83 , configured to receive the two stiffener plates; 
         FIG. 84B  is a perspective view of the stem of  FIG. 84A , illustrated with a portion cut away therefrom; 
         FIG. 85A  is a proximal end view of a link of the neck assembly of  FIG. 83 , configured to receive the two stiffener plates; 
         FIG. 85B  is a perspective view of the link of  FIG. 85A , illustrated with a portion cut away therefrom; 
         FIG. 86  is a cross-sectional view of another embodiment of a link of a neck assembly in accordance with the present disclosure, incorporating therein two stiffener plates; 
         FIG. 87  is a longitudinal cross-sectional view of the neck assembly of  FIG. 83  as taken through  87 - 87  of  FIG. 83 ; 
         FIG. 88  is another longitudinal, cross-sectional view of the neck assembly of  FIG. 83 ; and 
         FIG. 89  is a perspective view of a drive assembly according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates to devices, systems and methods for endoscopic, laparoscopic, endoluminal, and/or transluminal suturing. In one embodiment, for example, such a device comprises a handle. Handle assembly or other suitable actuating mechanism (e.g., robot, etc.) connected to a proximal end of a flexible, elongated body portion. A neck assembly operatively supported on a distal end of the flexible, elongated body portion allows an end effector, operatively supported at a distal end of the neck assembly, to articulate in response to actuation of articulation cables. The end effector includes a suture needle and a pair of jaws. In operation, the suture needle is passed back and forth through tissue from one jaw to the other. The device is adapted to be placed in a lumen of a flexible endoscope and then inserted into a natural orifice of a patient and transited endoluminally through the anatomy of the natural lumen to a treatment site within or outside the natural lumen. 
     In the drawings and in the description which follow, the term “proximal”, as is traditional, will refer to the end of the device which is closest to the operator, while the term “distal” will refer to the end of the device which is furthest from the operator. 
     Referring now in specific detail to the drawings, in which like reference numbers identify similar or identical elements,  FIGS. 1-3  illustrate a flexible stitching device, shown generally at  100 . Stitching device  100  is adapted to be particularly useful in endoscopic or laparoscopic procedures wherein an endoscopic portion of the stitching device, i.e., end effector, is insertable into an operative site, via a cannula assembly or the like (not shown). 
     As seen in  FIGS. 1-3 , stitching device  100  includes an end effector  200  of supportable on or extends from a handle assembly  300  and/or a distal end of an elongate tubular body portion  308  extending distally from handle assembly  300 . 
     As seen in  FIGS. 1-6, 9, 41 and 42 , end effector  200  includes a neck assembly  210  supported on a distal end of shaft  308  extending from handle assembly  300 , and a tool or jaw assembly  220  supported on a distal end of neck assembly  210 . Neck assembly  210  includes a plurality of links  212  each including a proximal knuckle  212   a  and a distal clevis  212   b  formed therewith. As seen in  FIGS. 41 and 42 , each knuckle  212   a  operatively engages a clevis  212   b  of an adjacent link  212 . Each link  212  defines a central lumen  212   c  (see  FIG. 42 ) formed therein and two pair of opposed lumen  212   d   1 ,  212   d   2  and  212   e   1 ,  212   e   2 , respectively, formed on either side of central lumen  212   c.  A pair of articulation cables  340 ,  342 , slidably extend through respective lumens  212   e   1 ,  212   e   2 , of links  212 . 
     Links  212  are configured to enable end effector  200  to move between a substantially linear configuration and a substantially angled, off-axis or articulated configuration. Links  212  are also configured so as to permit end effector  200  to be articulated in solely a single direction. For example, as seen in  FIGS. 5 and 6 , when end effector  200  is in a linear condition, the knuckles and devises on a first side of central lumen  212   c  are fully seated within one another, and the knuckles and devises on a second side of central lumen  212   c  are not fully seated within one another, thereby permitting end effector  200  to be articulated in the direction of the not fully seated side of central lumen  212   c.  Moreover, the knuckles and corresponding devises are dimensioned such that when end effector  200  is in the substantially linear configuration, the knuckles and the corresponding devises on the not fully seated side of central lumen  212   c  are at least aligned with one another or at least partially overlap one another. In this manner, the possibility of tissue, vessels or other body structures getting caught or pinched therebetween is reduced. 
     Operation of neck assembly  210  to articulate end effector  200  thereabout, will be discussed in greater detail below. 
     As seen in  FIGS. 1-4, 9, 49 and 50 , jaw assembly  220  of end effector  200  includes a jaw support member  222 , and a pair of jaws  230 ,  232  mounted for pivotable movement on jaw support member  222 . Jaw support member  222  defines a lumen  224  in a proximal end thereof and a pair of spaced apart arms  226  in a distal end thereof. As seen in  FIG. 49 , lumen  224  is configured and dimensioned to receive a stem  212   f  extending from a distal-most link  212  of neck assembly  210 . 
     As seen in  FIGS. 49-52 , jaw support member  222  defines an annular groove  224   a  formed in a surface of lumen  224  thereof and stem  212   f  defines an annular race  212   f   1  formed in an outer surface thereof. An annular groove  224   a  formed in a surface of lumen  224  of jaw support member  222  and annular race  212   f   1  formed in the outer surface of stem  212   f  are in registration with one another when stem  212   f  is connected to jaw support member  222 . A ring  213  is disposed within annular groove  224   a  formed in a surface of lumen  224  of jaw support member  222  and annular race  212   f,  formed in the outer surface of stem  212   f  to thereby maintain stem  212   f  connected to jaw support member  222  and permit rotation of jaw support member  222  relative to stem  212   f.    
     As seen in  FIGS. 4, 17 and 18 , each jaw  230 ,  232  includes a needle receiving recess  230   a,    232   a,  respectively, configured to surround and hold at least a portion of a needle  104  of a suture needle assembly  102  disposed therein substantially perpendicular to tissue engaging surfaces thereof. As seen in  FIG. 11 , needle  104  includes a groove  104   a  formed near each end thereof. A suture  106  may be secured to surgical needle  104  at a location between grooves  104   a.    
     Suture  106  of suture needle assembly  104  may comprise a one-way or barbed suture, wherein the suture includes an elongated body having a plurality of barbs extending therefrom. The barbs are oriented in such a way that the barbs cause the suture to resist movement in an opposite direction relative to the direction in which the barb faces. 
     Suitable sutures for use with suture needle assembly  104  include, and are not limited to, those sutures described and disclosed in U.S. Pat. Nos. 3,123,077; 5,931,855; and U.S. Patent Publication No. 2004/0060409, filed on Sep. 30, 2002, the entire content of each of which being incorporated herein by reference. 
     Jaws  230 ,  232  are pivotably mounted on support member  222  by means of a jaw pivot pin  234  which extends through holes  226   a  formed in arms  226  of support member  222  and respective pivot holes  230   b,    232   b  formed in jaws  230 ,  232 . To move jaws  230 ,  232  between an open position and a closed position there is provided an axially or longitudinally movable center drive rod assembly  236  having a camming pin  238  mounted at a distal end of a center drive rod distal portion  236   a.  Camming pin  238  rides in and engages angled camming slots  230   c,    232   c  formed in respective jaws  230 ,  232  such that axial or longitudinal movement of center rod assembly  236  causes jaws  230 ,  232  to be cammed between open and closed positions. 
     Jaw assembly  220  includes a drive assembly  240  slidably and rotatably disposed within lumen  224  of support member  222 . As seen in  FIGS. 9 and 12-14 , drive assembly  240  includes an inner drive assembly  242  and an outer drive assembly  244 . Inner drive assembly  242  includes an inner barrel or collar  242   a  defining a lumen  242   b  therethrough. Lumen  242   b  is configured to slidably and rotatably receive center drive rod distal portion  236   a  of center drive rod assembly  236  therein. Inner drive assembly  242  further includes a cuff  250   a  slidably and/or rotatably supported on inner barrel  242   a,  and a first blade  250   b  extending from cuff  250   a.  Blade  250   b  extends from cuff  250   a  in a direction substantially parallel to a central longitudinal axis of lumen  242   b  of inner barrel  242   a.    
     As seen in  FIGS. 9 and 12-14 , outer drive assembly  244  includes an outer barrel or collar  244   a  defining a lumen  244   b  therethrough and an annular recess  244   c  formed in a surface of lumen  244   b.  Lumen  244   b  is configured to slidably and rotatably receive inner barrel  242   a  therein, such that inner barrel  242   a  is nested within lumen  244   b  of outer barrel  244   a.  Outer drive assembly  244  further includes a cuff  252   a  slidably and/or rotatably supported in annular recess  244   c,  and a second blade  252   b  extending from ring  244   d.  Blade  252   b  extends from cuff  252   a  in a direction substantially parallel to a central longitudinal axis of lumen  244   b  of outer barrel  244   a.    
     Jaw assembly  220  further includes a clevis  246  disposed between arms  226  of support member  222 . Clevis  246  includes a pair of spaced apart arms  246   b  extending from a base  246   a.  Each arm  246   b  defines a lumen  246   c  therethrough. Clevis  246  defines a central aperture  246   d  formed in base  246   a.  Arms  246   b  are spaced apart an amount sufficient and central aperture  246   d  of base  246   b  is dimensioned so as to slidably and rotatably receive distal portion  236   a  of center rod assembly  236  therethrough. 
     Jaw assembly  220 , as discussed above, further includes a pair of needle engaging members or blades  250   b,    252   b  which are slidably supported within a respective lumen  246   c  of arms  246   b  of clevis  246 . Each blade  250   b,    252   b  includes a distal end slidably extending into blade receiving channels  230   d,    232   d  (see  FIG. 17 ) of respective jaws  230 ,  232 . Each blade  250   b ,  252   b  is resilient so as to flex or bend as jaws  230 ,  232  are opened and closed and still translate relative thereto when jaws  230 ,  232  are in either the open or closed condition. 
     In operation, as inner drive assembly  242  and outer drive assembly  244  are translated, in an axial direction, relative to one another. Blades  250   b,    252   b  are also translated with respect to one another. 
     Turning now to  FIGS. 1-3 and 7-10 , a detailed discussion of handle assembly  300  is provided. Handle assembly  300  includes a housing  302  having an upper housing half  304  and a lower housing half  306 . Handle assembly  300  further includes a pair of handles  310  pivotably secured to housing  302  and extending outwardly therefrom. 
     Housing halves  304 ,  306  of flexible stitching device may be joined together by snap-fit engagement or by suitable fasteners (e.g., screws) or the like. Housing  302  defines a window  304   a,    306   a  respectively formed in housing halves  304 ,  306 . Windows  304   a,    306   a  of housing halves  304 ,  306  are dimensioned to receive and provide access to an articulation assembly  330 . 
     As seen in  FIG. 9 , handles  310  are secured to housing  302  at handle pivot posts. Handle assembly  300  includes a link member  312  having a first end pivotably connected to each handle  310  at a pivot point  310   a  formed in a respective handle  310  and a second end pivotally connected to one another and pivotally connected to a proximal portion  236   b  of center drive rod assembly  236  via a drive pin  316 . Each end of drive pin  316  is slidably received in a respective elongate channel  304   b,    306   b  of housing halves  304 ,  306 . In use, as will be described in greater detail below, as handles  310  are squeezed, link members  312  push center drive rod assembly  236  proximally via drive pin  316 . 
     As mentioned above, handle assembly  300  includes a center drive rod assembly  236  translatably supported in housing  302 . Handle assembly  300  includes a biasing member  318 , in the form of a return spring, supported on proximal portion  236   b  of center drive rod assembly  236  and held in place between a surface  306   c  formed in lower housing half  306  and a retaining clip  318   a  connected to proximal portion  236   b  of center drive rod assembly  236 . 
     As seen in  FIGS. 9, 47 and 48 , a distal end proximal portion  236   b  of center drive rod assembly  236  is rotatably connected to a proximal end of an intermediate portion  236   c  of center drive rod assembly  236 . In this manner, intermediate portion  236   c  of center drive rod assembly  236  is free to rotate relative to proximal portion  236   b  of center drive rod assembly  236 . A sleeve  237  may be provided to maintain intermediate portion  236   c  of center drive rod assembly  236  and proximal portion  236   b  of center drive rod assembly  236  connected to one another. Intermediate portion  236   c  of center drive rod assembly  236  is connected to distal portion  236   a  of center drive rod assembly  236 . In operation, as proximal portion  236   b  of center drive rod assembly  236  is translated upon the actuation of handles  310 , said translation is transmitted to intermediate portion  236   c  and distal portion  236   a  of center drive rod assembly  236 . As described above, as distal portion  236   a  of center drive rod assembly  236  is translated camming pin  238 , mounted to distal portion  236   a  of center drive rod assembly  236 , rides in and engages angled camming slots  230   c,    232   c  formed in respective jaws  230 ,  232  to cause jaws  230 ,  232  to be cammed between open and closed positions. 
     Handle assembly  300  further includes an articulation assembly  330  rotatably supported in housing  302 . Articulation assembly  330  includes a threaded articulation sleeve  332  rotatably supported and axially fixed on center drive rod  314 , at a location distal of biasing member  318 . Threaded articulation sleeve  332  defines a distal thread and a proximal thread  332   a,    332   b,  respectively. 
     As seen in  FIGS. 9, 10, 19 and 20 , articulation assembly  330  further includes a distal articulation collar  334   a  and a proximal articulation collar  334   b  operatively connected to a respective thread  332   a,    332   b  of articulation sleeve  332 . Each collar  334   a,    334   b  defines a pair of radially extending tabs  334   a   1 ,  334   b   1 , respectively, that are in slidably engagement in elongate slots  304   d,    306   d  (see  FIG. 20 ) of upper and lower housing halves  304 ,  306 , respectively. Threads  332   a,    332   b  of articulation sleeve  332  and respective threads of distal and proximal articulation collars  334   a ,  334   b  are configured such that rotation of articulation sleeve  332  results in either approximation of distal and proximal articulation collars  334   a,    334   b  relative to one another when articulation sleeve  332  is rotated in a first direction or separation of distal and proximal articulation collars  334   a,    334   b  relative to one another when articulation sleeve  332  is rotated in a second direction. It is contemplated that the pitch of the threads between articulation sleeve  332  and articulation collars  334   a,    334   b  may be selected as necessary to achieve the intended purpose of approximating or separating the collars  334   a,    334   b  relative to one another. 
     Articulation assembly  330  further includes an articulation disk  336  rotatably disposed in housing  302  and keyed or otherwise secured to articulation sleeve  332 . In this manner, as articulation disk  336  is rotated, concomitant rotation is transmitted to articulation sleeve  332  and to distal and proximal articulation collars  334   a ,  334   b.  Articulation disk  336  is keyed or otherwise connected to an articulation knob  338  rotatably supported in housing  302  and accessible through windows  304   a,    306   a  of upper and lower housing halves  304 ,  306 . In operation, as articulation knob  338  is rotated, said rotation is transmitted to articulation disk  336 . 
     Articulation assembly  330  further includes a pair of articulation cables  340 ,  342  extending through and secured to end effector  200  and handle assembly  300 . A first articulation cable  340  includes a first end secured to proximal articulation collar  334   b  and a second end extending through distal articulation collar  334   a,  through a respective slot in articulation disk  336 , through respective lumen  212   e   1  of links  212 , and secured to distal-most link  212  or stem  212   f  of neck portion  210  (see  FIG. 18 ). A second articulation cable  342  includes a first end secured to distal articulation collar  334   a  and a second end extending through a respective slot in articulation disk  336 , through respective lumen  212   e   2  of links  212 , and secured to distal-most link  212  or stem  212   f  of neck portion  210  (see  FIG. 18 ). 
     In operation, as will be described in greater detail below, as articulation knob  338  is rotated, rotation is transmitted to articulation disk  336  and on to articulation sleeve  332 . As articulation sleeve  332  is rotated, distal and proximal articulation collars  334   a,    334   b  are approximated and/or separated relative to one another, and thus cause retraction of either first or second articulation cable  340 ,  342 , depending on the direction of rotation of articulation knob  338 . 
     Articulation assembly  330  further includes a biasing member  346  supported on intermediate portion  236   c  of center drive rod assembly  236 . 
     As seen in  FIGS. 1-3 and 7-14 , handle assembly  300  further includes a needle loading/retaining assembly  350  supported thereon. Needle loading/retaining assembly  350  includes a lever  352  pivotably supported in housing  302  and having a pair of arms  354   a ,  354   b  extending therefrom. Needle loading/retaining assembly  350  further includes a first blade control rod  356   a  and a second blade control rod  356   b.  Each blade control rod  356   a,    356   b  includes a proximal end connected to lever  352  at opposed sides of a pivot axis. In this manner, as lever  352  is actuated or pivoted in a first direction, first blade control rod  356   a  is moved in a first direction and second blade control rod  356   b  is moved in a second direction, opposite to the first direction, and vice-versa. A distal end of each blade control rod  356   a,    356   b  is connected to a respective inner drive assembly  242  and outer drive assembly  244 , in particular, to respective inner barrel  242   a  and outer barrel  244   a  of drive assembly  240 . 
     As seen in  FIGS. 12-14 , needle loading/retaining assembly  350  further includes resilient bendable rods  358   a,    358   b  interconnecting the distal end of each blade control rod  356   a ,  356   b  to respective inner barrel  242   a  and outer barrel  244   a  of drive assembly  240 . As seen in  FIGS. 13 and 14 , a rod  359   a,    359   b  may interconnect respective distal ends of blade control rods  356   a,    356   b  and inner and outer barrels  242   a,    244   a.    
     As seen in  FIGS. 9, 10, 20-22 and 26-30 , needle loading/retaining assembly  350  further includes a pair of needle loading/unloading buttons  360 ,  362  supported on housing  302 . Needle loading/unloading buttons  360 ,  362  are slidable between a distal-most position and a proximal-most position. When needle loading/unloading buttons  360 ,  362  are in the distal-most position, blades  250   b ,  252   b  are in a distal-most position such that a respective notch  250   c ,  252   c  formed therein, as seen in  FIG. 22 , is aligned with or in registration with respective needle receiving openings  230   a ,  232   a  of respective jaws  230 ,  232 . With blades  250   b ,  252   b  in a distal-most position, needle  104  of suture needle assembly  102  may be placed into a selected needle receiving opening  230   a ,  232   a  of a selected jaw  230 ,  232 . When needle loading/unloading buttons  360 ,  362  are in the proximal-most position blades  250   b ,  252   b  are in a proximal-most position such that the respective notch  250   c ,  252   c  formed therein is out of aligned with or registration with respective needle receiving openings  230   a ,  232   a  of respective jaws  230 ,  232 . With blades  250   b ,  252   b  in the proximal-most position, needle  104  of suture needle assembly  102 , placed into the selected needle receiving opening  230   a ,  232   a  of a selected jaw  230 ,  232 , is held in place due to the blade  250   b,    252   b  engaging a groove  104   a  of needle  104 . 
     As seen in  FIGS. 9, 20 and 21 , each button  360 ,  362  is supported on a respective biased stem  360   a ,  362   a  by a respective biasing member  360   b ,  362   b . As seen in  FIGS. 21 and 27-30 , stems  360   a ,  360   b  are slidably disposed within respective slots  304   e ,  306   e  of upper and lower housing halves  304 ,  306 . Each slot  304   e ,  306   e  includes an enlarged proximal end  304   f ,  306   f  configured to receive a portion of a respective stem  360   a ,  362   a  therein as buttons  360 ,  362  are moved to a proximal position. In order to move buttons  360 ,  362  in a distal direction, once stems  360   a ,  362   a  have seated in enlarged proximal ends  304   f ,  306   f  of slots  304   e ,  306   e  of upper and lower housing halves  304 ,  306 , the user must depress buttons  360 ,  362  to move stems  360   a ,  362   a  out of enlarged proximal ends  304   f ,  306   f  of slots  304   e ,  306   e  and thus allow for buttons  360 ,  362  to move distally. 
     As seen in  FIGS. 9, 10, 20 and 27 , needle loading/retaining assembly  350  is supported on a frame or bracket  368 . Bracket  368  is movable distally and proximally with lever  352  and is configured to permit passage of center drive rod assembly  236  therethrough. As seen in  FIG. 27 , biasing member  346  is interposed between bracket  368  and articulation sleeve  332 . In use, as buttons  360 ,  362  are moved in a proximal direction, bracket  368  is moved in a proximal direction to compress biasing member  346 . In this manner, when buttons  360 ,  362  are depressed to disengage stems  360   a ,  362   a  from enlarged proximal ends  304   f ,  306   f  of slots  304   e ,  306   e , biasing member  346  is permitted to expand the thus return buttons  360 ,  362  to a distal position. 
     As seen in  FIGS. 1-3, 7-10, 45 and 46 , handle assembly  300  further includes a tip rotation assembly  370  supported on housing  302  for rotating end effector  200  about the longitudinal axis thereof. Tip rotation assembly  370  includes a rotation knob  372  supported on housing  302 . Rotation knob  372  defines an annular array of internal gear teeth  372   a . Tip rotation assembly  370  includes a gear system  374  supported on a frame  376  in housing  302 . Gear system  374  includes at least a first gear  374   a  operatively engaged with gear teeth  372   a  of rotation knob  372 , at least a second gear  374   b  keyed to or otherwise connected to intermediate portion  236   c  of center drive rod assembly  236 , and at least a third gear  374   c  interconnecting the first gear  374   a  and the second gear  374   b  such that the direction of rotation of rotation knob  372  results in concomitant rotation of the intermediate portion  236   c  and the distal portion  236   a  of center drive rod assembly  236  and, in turn, end effector  200 . As intermediate portion  236   c  and distal portion  236   a  of center drive rod assembly  236  is rotated, said rotation is transmitted to caroming pin  238  of jaws  230 ,  232  and thus rotation is transmitted to end effector  200 . Since blades  250   b ,  252   b  are rotatably supported on respective barrels  242   a ,  244   a , blades  250   b ,  252   b  also rotate with end effector  200 . 
     Turning now to  FIGS. 15-53 , a detailed discussion of the operation of flexible endoscopic stitching device  100  is provided. As seen in  FIGS. 15-22 , stitching device  100  is shown in a needle load/unload configuration. When stitching device  100  is in the needle load/unload configuration, as seen in  FIGS. 16 and 20 , needle loading/retaining assembly  350  is in a distal position such that blades  250   b ,  252   b  are in a distal-most position and, as seen in  FIG. 22 , respective notches  250   c ,  252   c  formed therein, are aligned with or in registration with respective needle receiving openings  230   a ,  232   a  of respective jaws  230 ,  232 . With notches  250   c ,  252   c  of blades  250   b ,  252   b  aligned with or in registration with respective needle receiving openings  230   a ,  232   a  of respective jaws  230 ,  232 , as seen in  FIGS. 24-26 , needle  104  of suture needle assembly  102  may be positioned or loaded into a selected one needle receiving opening  230   a ,  232   a  of respective jaws  230 ,  232 . 
     As seen in  FIGS. 23-26 , once needle  104  is loaded into either needle receiving opening  230   a ,  232   a  of respective jaws  230 ,  232 , handles  310  are actuated (e.g., squeezed) to move link members  312  and, in turn, axially displace center drive rod assembly  236  in a proximal direction (as indicated by arrow “A” of  FIGS. 23 and 24 ). As seen in  FIGS. 24 and 25 , as center drive rod assembly  236  is moved in a proximal direction, camming pin  238  is moved in a proximal direction to approximate jaws  230 ,  232 . 
     As seen in  FIG. 27 , once needle  104  is loaded into either needle receiving opening  230   a ,  232   a  of respective jaws  230 ,  232 , needle loading/retaining assembly  350  is moved in a proximal direction to thereby retract blades  250   b ,  252   b  and cause each blade  250   b ,  252   b  to engage a respective groove  104   a  of needle  104 . 
     As seen in  FIGS. 31-35 , with needle  104  engaged by both blades  250   b ,  252   b , as seen in  FIGS. 31 and 32 , lever  352  is actuated or rotated so that only one blade  250   b ,  252   b , e.g., blade  252   b , is maintained in engagement with needle  104 , as seen in  FIG. 35 , and the other blade  250   b  is disengaged from needle  104 , as seen in  FIG. 34 . With only one blade, e.g., blade  252   b , engaged with needle  104 , as seen in  FIGS. 33-35 , handles  310  may be released, as seen in  FIG. 31 , thereby moving center drive rod assembly  236  and camming pin  238  in a distal direction to open jaws  230 ,  232 . 
     With jaws  230 ,  232  open, end effector  200  may be positioned at the surgical site as needed, and handles  310  reactuated to approximate jaws  230 ,  232 . For example, with jaws  230 ,  232  in an open position and needle  104  loaded therein, jaws  230 ,  232  may be positioned about or over a target tissue and handles  310  actuated to approximate jaws  230 ,  232 . As jaws  230 ,  232  are approximated, the exposed end of needle  104  is penetrated through the target tissue and enters into the opposed jaw  230 ,  232 . With needle  104  in the opposed jaw  230 ,  232 , as seen in  FIG. 36 , lever  352  is once again actuated or rotated so that blades  250   b ,  252   b  are reversed. In so doing, blade  252   b  is disengaged from needle  104  and blade  250   b  is engaged with needle  104 . 
     As seen in  FIG. 37 , with needle  104  engaged by blade  250   b , handles  310  may be released to thereby open jaws  230 ,  232  and draw needle  104  through the target tissue. In so doing, suture  106  is also drawn through the tissue. The process is repeated numerous times passing the needle  104  between jaws  230 ,  232  and drawing suture through the target tissue thereby suturing the target tissue as needed and or desired. 
     During a surgical procedure, if desired or necessary, as seen in  FIGS. 38-44 , a user may actuate articulation knob  338  of articulation assembly  330  to effectuate articulation or off-axis movement of end effector  200 . In particular, as articulation knob  338  is rotated, rotation is transmitted to articulation disk  336  and on to articulation sleeve  332 . As articulation sleeve  332  is rotated, distal and proximal articulation collars  334   a ,  334   b  are moved from an approximated condition to a more separated condition relative to one another, thus causing retraction of first articulation cable  340  and extension of second articulation cable  342 . 
     As seen in  FIGS. 43 and 44 , as first articulation cable  340  is retracted and second articulation cable  342  is extended, end effector  200  is articulated at neck portion  210 . As end effector  200  is articulated, intermediate portion  236   c  of center drive rod assembly  236  is flexed. In this manner, end effector  200  is still capable of rotation about its axis and jaws  230 ,  232  are still capable of opening and closing. 
     As seen in  FIG. 44 , while in an articulated condition, links  212  remain at least partially over-lapped in order to inhibit entry of tissue of the like therebetween. In this manner, when end effector  200  is returned to un-articulated or linear condition, tissue will not be caught or pinched between links  212  of neck portion  210 . 
     During a surgical procedure, if desired or necessary, as seen in  FIGS. 45-53 , a user may actuate rotation knob  372  of tip rotation assembly  370  to effectuate rotation of end effector  200  along a longitudinal axis thereof. In particular, as rotation knob  372  is rotated intermediate portion  236   c  and distal portion  236   a  of center drive rod assembly  236  is rotated. As intermediate portion  236   c  and distal portion  236   a  of center drive rod assembly  236  is rotated, said rotation is transmitted to camming pin  238  of jaws  230 ,  232  and thus rotation is transmitted to end effector  200 . 
     Turning now to  FIGS. 54-57 , a tip rotation assembly according to another embodiment of the present disclosure, for use with stitching device  100 , is generally designated as  470 . Tip rotation assembly  470  includes a rotation knob  472  supported on housing  302 . Knob  472  defines an arcuate slot  472   a  formed in a rear surface thereof and which arcuate slot  472   a  extends radially outward from a central rotational axis of knob  472  and extends approximately 180° about the central rotational axis. Tip rotation assembly  470  includes a collar  474  keyed to or otherwise secured to center drive rod assembly  236 . Tip rotation assembly  470  further includes a wishbone link  476  having a first end  476   a  pivotally connected to collar  474  and a second end  476   b  pivotally supporting a piston  478 . First end  476   a  of link  476  is curved about an axis transverse to a pivot axis thereof, so as to define a pocket  476   c  configured to selectively receive center drive rod assembly  236  therein. A pin  479  extends though piston  478  and connects piston  478  to arcuate slot  472   a.    
     Rotation assembly  470  includes a home position in which pin  479  is located at a first end of arcuate slot  472   a , where the arcuate slot  472   a  is furthest from the center drive rod assembly  236 . 
     In operation, in order to rotate end effector  200  about the longitudinal axis thereof, rotation knob  472  is rotated from the home position. As rotation knob  472  is rotated, pin  479  slidably translates through arcuate slot  472   a , approximating pin  479  toward center drive rod assembly  236 . As pin  479  is approximated toward center drive rod assembly  236 , wishbone link  476  is provided with sufficient clearance in order for wishbone link  476  to encircle center drive rod assembly  236 . In this way, rotation of knob  472  results in a transmission of a rotational force to center drive rod assembly  236  via piston  478 , wishbone link  476  and collar  474 . 
     Turning now to  FIGS. 58-62 , a tip rotation assembly according to another embodiment of the present disclosure, for use with stitching device  100 , is generally designated as  570 . Tip rotation assembly  570  includes a rotation knob  572  supported on housing  502 . Knob  572  defines an inner helical thread  572   a  formed in an inner surface thereof: Tip rotation assembly  570  includes a nut disposed within housing  502 . Nut  574  includes a pair of opposed stems  574   a  extending radially therefrom and through respective longitudinally extending slots  502   a  formed in housing  502 . Stems  574   a  of nut  574  are sufficiently long to engage helical thread  574   a  of rotation knob  574 . Nut  574  defines an inner helical thread  574   b.    
     Tip rotation assembly  570  further includes a lead screw  576  keyed to or otherwise connected to center drive rod assembly  236 . Lead screw  576  includes an outer thread or the like  576   a  which is configured to operatively engage inner helical thread  574   b  of nut  574 . Lead screw  576  is further axially fixed and rotatably supported in braces  502   b  formed in housing  502 . 
     In operation, as seen in  FIG. 62 , as rotation knob  572  is rotated, stems  574   a  of nut  574  are engaged by the inner helical thread  572   a  of rotation knob  572  and cause nut  574  to move axially through housing  502  and elongate slots  502   a  of housing  502 . As nut  574  moves axially though slots  502   a  of housing  502 , inner thread  574   a  thereof engages thread  576   a  of lead screw  576  causing lead screw  576  to rotate since lead screw  576  is axially fixed in braces  502   b  of housing  502 . As lead screw  576  rotates, lead screw  576  transmits said rotation to center drive rod assembly  236 . 
     Referring now to  FIGS. 63-69 , it is contemplated that each articulation cable  340 ,  342  may be operably associated with an arched seal  10  disposed in mechanical cooperation with center drive rod assembly  236 . Arched seal  10  includes a plurality of cable lumens  12   a , 12   d  (see 40  FIG. 65 ) disposed around a center drive rod lumen  14 , all extending therethrough. Center drive rod lumen  14  is configured to receive center drive rod assembly  236  therethrough. Each cable lumen  12   a , 12   d  is configured to receive one or more articulation cables  340 ,  342  in substantial sealing relationship therewith. Each cable lumen  12   a , 12   d  may have a respective arched section  16  that includes a venturi portion  16   a  configured to engage a surface of one or more articulation cables  340 ,  342  so that arched seal  10  may move with articulation cables  340 ,  342 . 
     Venturi portion  16   a  of each arched section  16  enables each cable lumen  12   a , 12   d  to be repositionable through a plurality of positions including a first position corresponding to a linear orientation of neck assembly  210  (e.g.,  FIG. 66 ) and a second position corresponding to an articulated orientation of neck assembly  210  (e.g.,  FIG. 68 ) in response to longitudinal translation of one or more articulation cables  340 ,  342  therethrough. In this manner, the sealing relationship between arched seal  10  and articulation cables  340 ,  342  is maintained at all times when neck assembly  210  is in either the linear or the articulated orientation. 
     Turning now to  FIGS. 70-72 , a tip rotation assembly according to another embodiment of the present disclosure, for use with stitching device  100 , is generally designated as  670 . Tip rotation assembly  670  includes a rotation knob  672  supported on housing  302  (see  FIG. 70 ) and a beveled gear assembly  680  operatively associated with rotation knob  672 . Beveled gear assembly  680  includes a sun gear  682  disposed in mechanical cooperation with knob  672 , a first beveled gear  684  that is operatively associated with sun gear  682 , and a second beveled gear  686  operatively associated with first beveled gear  684 . First beveled gear  684  may be generally orthogonally disposed relative to sun gear  682  and second beveled gear  686 . Second beveled gear  686  is disposed in mechanical cooperation with center drive rod assembly  236  for facilitating the transfer of rotational energy from tip rotation assembly  670  to center drive rod assembly  236  for opening and closing jaws  230 ,  232 . 
     Tip rotation assembly  670  further includes a first beveled gear mount  685  disposed in mechanical cooperation with first beveled gear  684  and knob  672 . First beveled gear mount  685  rotatably supports first beveled gear  684  relative to knob  672  and, in particular, interconnecting sun gear  682  and second beveled gear  606 . 
     Sun gear  682  and second beveled gear  686  may be configured and dimensioned to rotate about the longitudinal axis of the stitching device  100  in offset relationship relative to each other. First beveled gear mount  685  is configured to orient first beveled gear  684  such that first beveled gear  684  rotates about an axis transverse to the longitudinal axis of the stitching device  100 . Second beveled gear  686  may be keyed to or flat surfaces for engaging center drive rod assembly  236  while still allowing axial movement of center drive rod assembly  236  relative to second beveled gear  686 . Sun gear  682 , first beveled gear  684 , and second beveled gear  686  may be configured and dimensioned to collectively allow only minimal (e.g., five degrees) rotational backlash. In addition, beveled gear assembly  680  of tip rotation assembly  670  may be configured and dimensioned to translate rotational energy to the center drive rod assembly  236  in accordance with one or more of the following ratios: 1:1, more than 1:1, or less than 1:1. 
     In operation, as rotation knob  672  is rotated (may be clockwise or counterclockwise) about the longitudinal axis of the stitching device  100 , sun gear  682  (keyed to rotation knob  672 ) of beveled gear assembly  680  concentrically rotates therewith. Sun gear  682  engages with a first gear portion  684   a  of first beveled gear  684 , causing first beveled gear  684  to be rotated about an axis transverse to the longitudinal axis of the stitching device  100 . Rotation of the first beveled gear  684  causes second gear portion  684   b  of first beveled gear  684  to engage second beveled gear  686  and to rotate second beveled gear  686  about the longitudinal axis of the stitching device  100 . Rotation of the second beveled gear  686  causes the center drive rod assembly  236  to rotate and thus cause jaws  230 ,  232  to rotate. 
     Referring now to  FIGS. 73-78 , a handle assembly  1300  including another embodiment of an articulation assembly  1000  is shown. Articulation assembly  1000  includes an articulation cam  1010 , a first pin  1020 , a second pin  1030 , a first slider  1040 , a second slider  1050 , and first and second articulation cables  340 ,  342 . Articulation cam  1010  includes first and second articulation arms  1012 ,  1014 , and first and second cam disks  1016 ,  1018  for positioning articulation cam  1010  through a plurality of positions corresponding to a linear and/or angular orientation of neck assembly  210  including a first position ( FIG. 76 ), a second position ( FIG. 77 ), and a third position ( FIG. 78 ). 
     Articulation cam  1010  is supported in a housing  1302  of handle assembly  1300 . First and second cam disks  1016 ,  1018  define opposing respective first and second camming channels  1016   a ,  1018   a  therein. First and second camming channels  1016   a ,  1018   a  may have a shape substantially similar to a logarithmic spiral that may be configured to provide equidistant linear motion directly proportional to the angular rotation of first and second cam disks  1016 ,  1018 . As such, each articulation cable  340 ,  342  may remain substantially taut upon translation thereof relative to housing  1302 . 
     Referring again to  FIGS. 73-78 , first pin  1020  is operably associated with first camming channel  1016   a  of first cam disk  1016  and with first slider  1040 . First slider  1040  is configured to longitudinally translate in a channel defined in housing  1302 . Second pin  1030  is operably associated with second camming channel  1018   a  of second cam disk  1018  and with second slider  1050 . Second slider  1050  is configured to longitudinally translate in a channel defined in housing  1302 . First and second sliders  1040 ,  1050  are secured to respective proximal ends of first and second articulation cables  340 ,  342 . Distal ends of first and second articulation cables  340 ,  342  are secured at a location distal of the neck assembly  210 , as described above. Articulation cables  340 ,  342  are disposed on opposed sides of center drive rod assembly  236 . 
     In operation, to articulate neck assembly  210 , articulation cam  1010  is rotated via first and/or second articulation arms  1012 ,  1014 . As seen in  FIGS. 73-78 , as articulation cam  1010 , is rotated, first and second pins  1020 ,  1030  translate through respective first and second camming channels  1016   a ,  1018   a  of first and second cam disks  1016 ,  1018 , and cause respective first and second sliders  1040 ,  1050  to longitudinally translate. As first and second sliders  1040 ,  1050  longitudinally translate, either first or second articulation cables  340 ,  342  retract, depending on the direction of the rotation of the articulation cam  1010 , thereby causing neck assembly  210  to articulate. In this manner, one articulation cable  340 ,  342  is retracted, while the other articulation cable  340 ,  342  extends precisely the same length as the other shortens. The retraction and extension of the articulation cables  340 ,  342  are proportional with the curvature of first and second camming channels  1016   a ,  1018   a  of first and second cam disks  1016 ,  1018 . 
     In other words, upon articulation of neck assembly  210 , the articulation cable  340 ,  342  translating in a distal direction must travel a greater distance as compared to articulation cable  340 ,  342  translating in a proximal direction. As such, in order to compensate for any slack in the tension of articulation cables  340 ,  342 , first and second camming channels  1016   a ,  1018   a  have been shaped to cause greater proximal translation of articulation cable  340  or  342  the greater the degree of rotation of first and/or second actuation arms  1012 , 1014 . 
     First and second cam disks  1016 ,  1018  may be monolithically formed. As illustrated in another embodiment of an articulation cam designated generally as  2010  and shown in  FIG. 79 , first and second cam disks  2016 ,  2018  may be separate and distinct such that each may rotate in opposed rotational directions via first and second articulation arms  2012 ,  2014 . A torsion spring  2015  may operably couple first and second cam disks  2016 ,  2018  such that distal and proximal ends of torsion spring  2015  are disposed in mechanical cooperation with respective first and second cam disks  2016 ,  2018 . Torsion spring  2015  may be supported on a shaft axially disposed between first and second cam disks  2016 ,  2018  to facilitate about 10 to 15 degree rotation of each cam disk  2016 ,  2018  in relation to each other. Torsion spring  2015  may be preloaded such that it generates force sufficient for maintaining articulation cables  340 ,  342  in tension for precision operation of the stitching device  100 , yet configured to limit rotation of first and second cam disks  2016 ,  2018  relative to each other during articulation of the neck assembly  210 . 
     As illustrated in other embodiments of articulation assemblies  3000 ,  4000 ,  5000  shown in  FIGS. 80-82 , articulation cables  340 ,  342  may be attached directly to first or second pins  1020 ,  1030  that are disposed in mechanical cooperation with respective first and second cam disks  1016 ,  1018 ,  2016 ,  2018  for providing longitudinal translation. As illustrated in the embodiments shown in  FIGS. 80-81 , articulation cables  340 ,  342  may be redirected by one or more rollers “R” mounted at various positions on housing  302 ,  1302 . As such, first and second cam disks  1016 ,  1018 ,  2016 ,  2018  may be positioned in longitudinal alignment with the longitudinal axis of the stitching device, transverse thereto, or any other variation thereof since rollers “R” may redirect the articulation cables  340 ,  342  in any direction, depending on placement thereof. 
     Turning now to  FIGS. 83-88 , an alternate embodiment of a neck assembly is generally designated as  1210 . Neck assembly  1210  is similar to neck assembly  210  and thus will only be discussed herein to the extent necessary to identify differences in construction and operation thereof. 
     As seen in  FIGS. 83-88 , each link  212  defines a pair of opposed stiffener plate receiving slots  216   a ,  216   b . Slots  216   a ,  216   b  are fanned on either side of central lumen  212   c  and are interposed between central lumen  212   c  and a respective articulation cable lumen  212   e   1 ,  212   e   2 . As shown in  FIGS. 83 and 88 , neck assembly  1210  includes a pair of stiffener plates  218   a ,  218   b  translatably disposed in the plate receiving slots  216   a ,  216   b , respectively. As seen in  FIG. 87 , a distal-end of each stiffener plate  218   a ,  218   b  includes an anchor portion  219  to securely attach respective distal-end of stiffener plate  218   a ,  218   b  to stem  212   f  of neck assembly  1210 , while allowing the proximal-end of each stiffener plate  218 ,  218   b  to translate freely through plate receiving slots  216   a ,  216   b.    
     In an embodiment, as seen in  FIG. 87 , anchor portion  219  of each stiffener plate  218   a ,  218   b  may be bifurcated and include a pair of spaced apart tines that snap-fit into packets formed at the ends of plate receiving slots  216   a ,  216   b . Each stiffener plate  218   a ,  218   b  may have an elongated, flattered (e.g., ribbon-like) profile. Each stiffener plate  218   a ,  218   b  thus defines a plane, wherein the stiffener plates  218   a ,  218   b  are supported in neck assembly  1210  such that the respective planes of stiffener plates  218   a ,  218   b  are substantially parallel with one another. In the present embodiment, the planes of stiffener plates  218   a ,  218   b  are oriented substantially orthogonal to a direction of articulation of end effector  200 . Stiffener plates  218   a ,  218   b  may be constructed from any durable resilient material, such as, for example, stainless steel, titanium, etc. 
     Links  212  are configured to enable end effector  200  to move between a substantially linear configuration and a substantially angled, off-axis or articulated configuration. Since stiffener plates  218   a ,  218   b  are oriented such that the planes thereof are substantially orthogonal to a direction of articulation of end effector  200 , movement or articulation of end effector  200  is restricted solely in two dimensions (i.e., a single plane). As illustrated in  FIG. 87 , stiffener plate  218   a  (and stiffener plate  218   b , not shown) restrict(s) movement or canting of end effector  200  in the direction of arrows “A.” 
     Turning now to  FIG. 89 , an alternate embodiment of a drive assembly is generally designated as  2240 . Drive assembly  2240  is similar to drive assembly  240  and thus will only be discussed herein to the extent necessary to identify differences in construction and operation thereof. As seen in  FIG. 89 , drive assembly  2240  includes an inner drive member  2242  and an outer drive member  2244 . Inner drive member  2242  includes a partially circular collar  2242   a  and a first blade  2250   b  extending therefrom. First blade  2250   b  and the partially circular collar  2242   a  are constructed or stamped as one unitary member from one piece of sheet metal. Similarly, outer drive member  2244  includes a partially circular collar  2244   a  and a second blade  2252   b  extending therefrom. Second blade  2252   b  and the partially circular collar  2244   a  are also constructed or stamped as one unitary member from one piece of sheet metal. The partially circular collar  2242   a  of inner drive member  2242  is nested within the partially circular collar  2244   a  of outer drive member  2244  and defines a lumen  2242   b  through which center drive rod distal portion  236   a  of center drive rod assembly  236  is received. Inner and outer drive members  2242 ,  2244  provide a snap feature that snaps around inner and outer bushings (not shown), thereby allowing rotation of inner and outer drive members  2242 ,  2244  around the inner and outer bushings, respectively. Such design reduces the number of parts that are required to hold blades  2250   b ,  2252   b  in place, thereby simplifying manufacturability and reducing cost of manufacturing. 
     While the disclosure has been particularly shown and described with reference to particular embodiments, it will be understood by those skilled in the art that various modifications in form and detail may be made therein without departing from the scope and spirit of the invention. Accordingly, modifications such as those suggested above, but not limited thereto, are to be considered within the scope of the invention.