Patent Publication Number: US-2023157745-A1

Title: Jaw tip support for tapered jaw member

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 63/281,185 filed Nov. 19, 2021, the entire contents of which being incorporated by reference herein. 
    
    
     FIELD 
     The present disclosure relates to surgical instruments and, more specifically, to end effector assemblies for surgical instruments, such as for use in robotic surgical systems. 
     BACKGROUND 
     Robotic surgical systems are increasingly utilized in various different surgical procedures. Some robotic surgical systems include a console supporting a robotic arm. One or more different surgical instruments may be configured for use with the robotic surgical system and selectively mountable to the robotic arm. The robotic arm provides one or more inputs to the mounted surgical instrument to enable operation of the mounted surgical instrument. 
     A surgical forceps, one type of instrument capable of being utilized with a robotic surgical system, relies on mechanical action between its jaw members to grasp, clamp, and constrict tissue. Electrosurgical forceps utilize both mechanical clamping action and energy to heat tissue to treat, e.g., coagulate, cauterize, or seal, tissue. Typically, once tissue is treated, the tissue is severed using a cutting element. Certain electrosurgical forceps utilize a tapered jaw design to facilitate dissection and access to smaller operating cavities. Manufacturing a jaw member with a consistent strength and stiffness profiles to absorb the necessary closure pressures associated with tissue sealing can present design challenges especially at the tapered distal tip. 
     SUMMARY 
     As used herein, the term “distal” refers to the portion that is being described which is further from an operator (whether a human surgeon or a surgical robot), while the term “proximal” refers to the portion that is being described which is closer to the operator. The terms “about,” substantially,” and the like, as utilized herein, are meant to account for manufacturing, material, environmental, use, and/or measurement tolerances and variations, and in any event may encompass differences of up to 10%. Further, to the extent consistent, any of the aspects described herein may be used in conjunction with any or all of the other aspects described herein. 
     Provided in accordance with aspects of the present disclosure is a jaw member of an electrosurgical instrument which includes a U-shaped structural frame defining a cavity therein and extending therealong configured to receive at least a portion of an insulative spacer therein such that the insulative spacer extends distally therefrom. The insulative spacer includes a tapered fin at a distal end thereof. A tissue treating plate is disposed on the face of the insulative spacer, the tissue treating plate is adapted to connect to a source of energy to treat tissue therewith. The tapered fin is configured to extend to and support a distal end of the tissue treating plate. 
     In an aspect of the present disclosure, the insulative spacer is configured to electrically isolate the structural frame from the tissue treating plate. 
     In an aspect of the present disclosure, the tapered fin includes an overhang on either side thereof configured to laterally support the distal end of the tissue treating plate. 
     In an aspect of the present disclosure, the jaw member includes an outer insulative jacket disposed about at least a portion of an outer face of the structural frame and the insulative spacer. In other aspects of the present disclosure, the outer insulative jacket is overmolded about the structural frame and the insulative spacer. 
     In an aspect of the present disclosure, the insulative spacer is made from a material selected from the group consisting of: PPA, PTFE, PEEK, PBI and PEI. 
     In an aspect of the present disclosure, the draft angle of the tapered fin is about 0.5 degrees. The draft angle may be in the range of about 3 degrees to about 10 degrees. 
     In an aspect of the present disclosure, the insulative spacer is configured to receive a thermal cutting element therein and extending therealong. In other aspects of the present disclosure, the insulative spacer is configured to electrically isolate the structural frame from the thermal cutting element. 
     Provided in accordance with aspects of the present disclosure is an end effector of an electrosurgical instrument which includes first and second jaw members pivotably coupled to one another such that at least one of the first or second jaw members is movable relative to the other from a spaced-apart position to an approximated position to grasp tissue therebetween. Each of the first and/or second jaw members includes: a U-shaped structural frame defining a cavity therein and extending therealong configured to receive at least a portion of an insulative spacer therein such that the insulative spacer extends distally therefrom, the insulative spacer includes a tapered fin at a distal end thereof; and a tissue treating plate disposed on the face of the insulative spacer, the tissue treating plates of each jaw member disposed in vertical opposition relative to one another and each tissue treating plate is adapted to connect to an opposite potential from a source of energy to treat tissue therewith, each tapered fin is configured to extend to and support a distal end of the respective tissue treating plate. 
     In an aspect of the present disclosure, each insulative spacer is configured to electrically isolate the structural frame from the tissue treating plate of each respective jaw member. 
     In an aspect of the present disclosure, each tapered fin includes an overhang on either side thereof configured to laterally support the distal end of the tissue treating plate of each respective jaw member. 
     In an aspect of the present disclosure, each jaw member includes an outer insulative jacket disposed about at least a portion of an outer face of the structural frame and the insulative spacer of each respective jaw member. In other aspects of the present disclosure, the outer insulative jacket is overmolded about the structural frame and the insulative spacer of each respective jaw member. 
     In an aspect of the present disclosure, the insulative spacer of each jaw member is made from a material selected from the group consisting of: PPA, PTFE, PEEK, PBI and PEI. 
     In an aspect of the present disclosure, the draft angle of each tapered fin is about 0.5 degrees. The draft angle may be in the range of about 3 degrees to about 10 degrees. 
     In an aspect of the present disclosure, the insulative spacer of the first jaw member is configured to receive a thermal cutting element therein and extending therealong. In other aspects of the present disclosure, the insulative spacer of the first jaw member is configured to electrically isolate the structural frame from the thermal cutting element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects and features of the present disclosure are described hereinbelow with reference to the drawings wherein: 
         FIG.  1    is a perspective view of a surgical instrument in accordance with the present disclosure configured for mounting on a robotic arm of a robotic surgical system; 
         FIG.  2    is a rear perspective view of a proximal portion of the surgical instrument of  FIG.  1    with an outer housing removed; 
         FIG.  3    is a schematic illustration of an exemplary robotic surgical system configured to releasably receive the surgical instrument of  FIG.  1   . 
         FIG.  4    is a side view of an end effector assembly of the forceps of  FIG.  1    including first and second jaw members; 
         FIG.  5    is a perspective view of a first jaw member of the end effector assembly with outer insulative jackets removed therefrom to expose an insulative spacer; 
         FIG.  6    is a transverse, cross-sectional view of the first jaw member of the end effector assembly as shown in  FIG.  4   ; and 
         FIG.  7    is an enlarged view of the distal tapered fin of the insulative spacer of the jaw member of  FIG.  5   . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS.  1  and  2   , a surgical instrument  10  provided in accordance with the present disclosure generally includes a housing  20 , a shaft  30  extending distally from the housing  20 , an end effector assembly  100  extending distally from the shaft  30 , and an actuation assembly  300  disposed within the housing  20  and operably associated with the shaft  30  and the end effector assembly  100 . The surgical instrument  10  is detailed herein as an articulating electrosurgical forceps configured for use with a robotic surgical system, e.g., robotic surgical system  500  ( FIG.  3   ). However, the aspects and features of the surgical instrument  10  provided in accordance with the present disclosure, detailed below, are equally applicable for use with other suitable surgical instruments (including non-robotic surgical instrument) and/or in other suitable surgical systems (including non-robotic surgical systems). 
     The housing  20  of the surgical instrument  10  includes first and second body portions  22   a ,  22   b  and a proximal faceplate  24  ( FIG.  2   ) that cooperate to enclose the actuation assembly  300  therein. The proximal faceplate  24  includes apertures defined therein through which inputs  410 ,  420 ,  430 ,  440  of the actuation assembly  300  extend. A pair of latch levers extends outwardly from opposing sides of the housing  20  and enables releasable engagement (directly or indirectly) of the housing  20  with a robotic arm of a surgical system, e.g., robotic surgical system  500  ( FIG.  3   ). An aperture  28  defined through the housing  20  permits a thumbwheel  640  to extend therethrough to enable manual manipulation of the thumbwheel  640  from the exterior of the housing  20  to permit manual opening and closing of the end effector assembly  100 . 
     The shaft  30  of the surgical instrument  10  includes a distal segment  32  (such as, for example, a collar or clevis), a proximal segment  34 , and an articulating section  36  disposed between the distal and proximal segments  32 ,  34 , respectively. The articulating section  36  includes one or more articulating components  37 , e.g., links, joints, etc. A plurality of articulation cables  38 , e.g., four (4) articulation cables, or other suitable actuators, extends through the articulating section  36 . More specifically, the articulation cables  38  are operably coupled to the distal segment  32  of the shaft  30  at the distal ends thereof and extend proximally from the distal segment  32  of the shaft  30 , through the articulating section  36  and the proximal segment  34  of the shaft  30 , and into the housing  20 , wherein the articulation cables  38  operably couple with an articulation assembly  200  of the actuation assembly  300  to enable selective articulation of the distal segment  32  (and, thus the end effector assembly  100 ) relative to the proximal segment  34  and the housing  20 , e.g., about at least two axes of articulation (yaw and pitch articulation, for example). The articulation assembly  200  is operably coupled between the first and second inputs  410 ,  420 , respectively, of the actuation assembly  300  and the articulation cables  38  ( FIG.  1   ) such that, upon receipt of appropriate rotational inputs into the first and/or second inputs  410 ,  420 , the articulation assembly  200  manipulates the articulation cables  38  to articulate the end effector assembly  100  in a desired direction, e.g., to pitch and/or yaw the end effector assembly  100 . The articulation cables  38  are arranged in a generally rectangular configuration, although other suitable configurations are also contemplated. 
     With respect to articulation of the end effector assembly  100  relative to the proximal segment  34  of the shaft  30 , actuation of the articulation cables  38  is effected in pairs. More specifically, in order to pitch the end effector assembly  100 , the upper pair of cables  38  is actuated in a similar manner while the lower pair of cables  38  is actuated in a similar manner relative to one another but an opposite manner relative to the upper pair of cables  38 . With respect to yaw articulation, the right pair of cables  38  is actuated in a similar manner while the left pair of cables  38  is actuated in a similar manner relative to one another but an opposite manner relative to the right pair of cables  38 . 
     Turning now to  FIG.  3   , a robotic surgical system  500  is configured for use in accordance with the present disclosure. Aspects and features of the robotic surgical system  500  not germane to the understanding of the present disclosure are omitted to avoid obscuring the aspects and features of the present disclosure in unnecessary detail. 
     The robotic surgical system  500  generally includes a plurality of robot arms  502 ,  503 ; a control device  504 ; and an operating console  505  coupled with control device  504 . The operating console  505  may include a display device  506 , which may be set up in particular to display three-dimensional images; and manual input devices  507 ,  508 , by means of which a person, e.g., a surgeon, may be able to telemanipulate the robot arms  502 ,  503  in a first operating mode. The robotic surgical system  500  may be configured for use on a patient  513  lying on a patient table  512  to be treated in a minimally invasive manner. The robotic surgical system  500  may further include a database  514 , in particular coupled to the control device  504 , in which are stored, for example, pre-operative data from the patient  513  and/or anatomical atlases. 
     Each of the robot arms  502 ,  503  may include a plurality of members, which are connected through joints, and a mounted device which may be, for example, a surgical tool “ST.” One or more of the surgical tools “ST” may be the surgical instrument  10  ( FIG.  1   ), thus providing such functionality on a robotic surgical system  500 . 
     Specifically, the actuation assembly  300  ( FIG.  2   ) is configured to operably interface with the robotic surgical system  500  when the surgical instrument  10  is mounted on the robotic surgical system  500  to enable robotic operation of the actuation assembly  300 . That is, the robotic surgical system  500  selectively provides rotational inputs to inputs  410 ,  420 ,  430 ,  440  of the actuation assembly  300  to articulate the end effector assembly  100 , grasp tissue between the first and second jaw members  110 ,  120 , and/or cut tissue grasped between the first and second jaw members  110 ,  120 . 
     The robot arms  502 ,  503  may be driven by electric drives, e.g., motors, connected to the control device  504 . The control device  504 , e.g., a computer, may be configured to activate the motors, in particular by means of a computer program, in such a way that the robot arms  502 ,  503 , and, thus, their mounted surgical tools “ST” execute a desired movement and/or function according to a corresponding input from the manual input devices  507 ,  508 , respectively. The control device  504  may also be configured in such a way that it regulates the movement of the robot arms  502 ,  503  and/or of the motors. 
     Turning to  FIGS.  4 - 7   , end effector assembly  100 , as noted above, includes first and second jaw members  110 ,  120 . Either or both jaw members  110 ,  120  may include a structural frame  111 ,  121 , an insulative spacer  112 ,  122 , a tissue treating plate  113 ,  123  defining the respective tissue treating surface  114 ,  124  thereof, and, in aspects, an outer insulative jacket  116 ,  126 . Tissue treating plates  113 ,  123  may be pre-formed and engaged with insulative spacers  112 ,  122  and/or other portion(s) of jaw members  110 ,  120  via, for example, overmolding, adhesion, mechanical engagement, etc., or may be deposited onto insulative spacers  112 ,  122 , e.g., via sputtering or other suitable deposition technique. 
     Referring in particular to  FIG.  5   , jaw member  120 , as noted above, includes a generally U-shaped structural frame  121 , an insulative spacer  122 , a tissue treating plate  123  defining a tissue treating surface  124 , and, in aspects, an outer insulative jacket  126  ( FIG.  4   ). Structural frame  121  may be formed from stainless steel or other suitable material configured to provide structural support to jaw member  120 . Structural frame is typically stamped in a U-shaped configuration and defines a cavity  121   a  defined therealong configured to at least partially receive the insulative space  122 . The frame may be forged, cast or otherwise fabricated. Structural frame  121  includes a proximal flange portion  152  about which jaw member  120  is pivotably coupled to jaw member  110  via pivot  103  ( FIG.  4   ) and a distal body portion  154  that supports the other components of jaw member  120 , e.g., insulative spacer  122 , tissue treating plate  123 , and outer insulative jacket  126  (where provided). In shaft-based or robotic configurations, proximal flange portion  152  enables operable coupling of jaw member  120  to the actuation assembly  200  to enable pivoting of jaw member  110  relative to jaw member  120  in response to actuation thereof. Many suitable drive arrangements are contemplated, e.g., using cam pins and cam slots, a screw-drive mechanism, etc. 
     Insulative spacer  122  of jaw member  120  is formed from an electrically insulative material capable of withstanding high temperatures, e.g., above at least 300° C., although other configurations are also contemplated. Insulative spacer  122  may be formed from ceramic or other suitable material, e.g., PPA, PTFE, PEEK, PBI and PEI. Insulative spacer  122  may include various cutout or apertures defined therealong to facilitate assembly of jaw member  120 . 
     Continuing with reference to  FIG.  5   , insulative spacer  122  is configured for at least partial receipt within distal body portion  154  of structural frame  121  and may be at least partially shaped complementary thereto. Insulative spacer  122  may include one or more alignment features to facilitate assembly to frame  121 , e.g., alignment bosses, flanges, etc. Overhang  176  of insulative spacer  122  is configured to be supported on longitudinally extending sides of the distal body portion  154  of structural frame  121  ( FIG.  6   ). Overhang  176  may also be configured to provide electrical insulation between the seal plate and other structural components. 
     Referring again to  FIGS.  4 - 7   , as noted above, tissue treating plate  123  is supported or received on insulative spacer  122 . In aspects, tissue treating plate  123  overlaps the overhangs  176  of insulative spacer  122 , although other configurations are also contemplated. As noted above, tissue treating plate  123  may be pre-formed and engaged with insulative spacer  122  or may be deposited onto insulative spacers  122 , e.g., via sputtering or other suitable deposition technique. In aspects where tissue treating plate  123  is pre-formed and engaged with insulative spacer  122 , tissue treating plate  123  may be secured to jaw member  120  and, thus, insulative spacer  122 , via overmolding of outer insulative jacket  126  about distal body portion  154  of structural frame  121  of tissue treating plate  123 . Tissue treating plate  123  may include a longitudinally extending slot  128  defined therethrough and along at least a portion of the length thereof. 
     Slot  128  may be transversely centered on tissue treating surface  124  or may be offset relative thereto and may be linear, curved, include angled sections, etc. similarly or differently from the configuration, e.g., curvature, of jaw member  120 . Slot  128  exposes a portion of insulative spacer  122  and may be recessed relative to tissue treating surface  124 , substantially co-planar with tissue treating surface  124 , or protruding beyond tissue treating surface  124  towards jaw member  110 . In other aspects, slot  128  is omitted and, thus tissue treating plate  123  extends continuously insulative spacer  122  without exposing any portion thereof. 
     Regardless of the particular configuration of tissue treating plate  123 , insulative spacer  122  electrically isolates tissue treating plate  123  from structural frame  121 . Tissue treating plate  123  is electrically connected, e.g., via one or more electrical leads (not shown), to an activation switch (not shown)) and an electrosurgical generator “G” ( FIG.  1   ) to enable selective energization of tissue treating plate  123 , e.g., as one pole of a bipolar Radio Frequency (RF) electrosurgical circuit. However, other suitable energy modalities, e.g., thermal, ultrasonic, light, microwave, infrared, etc., are also contemplated. Jaw member  120  further includes a thermal cutting element  130  which may be connected to the same (e.g., generator “G”) or alternate electrical energy source. A mechanical cutting element (not shown) may also be employed which is configured to translate a cutting blade through the tissue upon selective application thereof. 
     A second activation switch (not shown) may be integrated with the robotic system  500  and coupled to the thermal cutting element  130  and to the electrosurgical generator “G” for enabling the selective activation of the supply of energy to the thermal cutting element  130  for thermally cutting tissue. 
     Thermal cutting element  130  may be secured within and directly to insulative spacer  122  in any suitable manner, e.g., adhesive, friction fitting, mechanical engagement, etc., or may be indirectly secured within insulative spacer  122  via attachment to one or more other components of jaw member  120 . Thermal cutting element  130  may protrude distally beyond the distal tip of insulative spacer  122  of jaw member  120 , may be substantially flush therewith, or may be recessed relative thereto. In aspects where end effector assembly  100 , or a portion thereof, is curved, thermal cutting element  130  may similarly be curved. Thermal cutting element  130  is electrically connected, e.g., via one or more electrical leads (not shown), to electrosurgical generator “G” ( FIG.  1   ) to enable selective activation of the supply of energy to thermal cutting element  130  for heating thermal cutting element  130  to thermally cut tissue. Thermal cutting element  130 , more specifically, may be configured to cut previously (or concurrently) sealed tissue grasped between jaw members  110 ,  120 , to cut tissue extending across jaw member  120 , and/or to cut tissue adjacent the distal end of jaw member  120 . 
     Thermal cutting element  130  may be any suitable thermal cutting element such as, for example, a resistive cutting element, a ferromagnetic cutting element, a monopolar cutting element, a bipolar cutting element, etc. With respect to resistive cutting elements, thermal cutting element  130  may include a substrate, e.g., aluminum, ceramic, stainless steel, etc., an insulative coating disposed on the substrate, e.g., a Plasma Electrolytic Oxidation (PEO)-formed coating, a sprayed coating, a deposited coating, or other suitable coating, and a heating circuit trace disposed on the coating such that when an AC voltage is applied to the heating circuit trace, the thermal cutting element  130  is heated for thermally cutting tissue in contact therewith or adjacent thereto. 
     With reference to  FIG.  4   , jaw member  110  includes a structural frame  111 , an insulative spacer  112 , a tissue treating plate  113  defining tissue treating surface  114 , and, in aspects, an outer insulative jacket  116 . Jaw member  110  is similar to jaw member  120  with the general exception of thermal cutting element  130  being housed therein. 
     Structural frame  121  of jaw member  120  defines a proximal flange portion  152  and a distal body portion  154  extending distally from proximal flange portion  152 . Proximal flange portion  152  may be bifurcated to define a pair of spaced apart proximal flange portion segments or may define any other suitable configuration. Proximal flange portion  152  of jaw member  120  and proximal flange portion  188  of jaw member  110  may define a nestled configuration, e.g., wherein one of the proximal flange portions  152 ,  188  is received within the other, an overlapping configuration, e.g., wherein proximal flange portions  152 ,  188  at least partially overlap one another, or an offset configuration, e.g., wherein proximal flange portions  152 ,  188  are positioned in side-by-side relation. Regardless of the particular arrangement of proximal flange portions  152 ,  188 , proximal flanges are configured for receipt of pivot  103 , e.g., welded or otherwise secured therein, to pivotably couple jaw members  110 ,  120  with one another. 
     Insulative spacer  112  of jaw member  110  may be configured similarly as and may include any of the features of insulative spacer  122  of jaw member  120  and, thus, only differences therebetween are described below. For example, tissue treating plate  113  defines tissue treating surface  114  and is supported on insulative spacer  112  similarly as tissue treating plate  123  is supported on insulative spacer  122 . Tissue treating plate  113  may be formed similarly to and/or include any of the features of tissue treating plate  123  and may be secured to jaw member  110  similarly as tissue treating plate  123  is secured to jaw member  120 , e.g., via overmolding of outer insulative jacket  116 . Insulative spacer  112  electrically isolates tissue treating plate  113  from structural frame  111 . 
     Details relating to the spacer  122  are described in more detail below with reference to  FIGS.  4 - 7   . More particularly, spacer  122  includes a reduced profile at a distal end thereof that is shaped like a fin  122   a  that extends under and supports the corresponding distal end  123   a  of the tissue treating plate  123 . In order to reduce the configuration of the jaw members  110 ,  120  (only jaw member  120  is shown in detail but the configuration of the spacer  112  is substantially the same) to a tapered profile at a distal end thereof, the stamped (or otherwise fabricated), U-shaped configuration of the structure frame, e.g., frame  121 , is reduced in length proximate the distal end of the jaw member  120  for manufacturing purposes. In other words, the thinner the profile of the frame  121  the more difficult it is to form the U-shape at a distal end. As a result, the structural frame, e.g., frame  121 , does not support the distal end  123   a  of the tissue treating plate  123 . 
     To avoid inconsistencies in pressure between the jaw members  110 ,  120  along the length thereof during sealing, the distal ends  113   a ,  123   a  of the of the jaw members  110 ,  120 , respectively, are supported by the corresponding fins  112   a  ( FIG.  4   ),  122   a  associated with each of the same. Overhangs  175  ( FIGS.  4   ) and  176  ( FIG.  6   ), which extend laterally from respective fins  112   a ,  122   a , transversally support the distal tips  113   a ,  123   a  of the tissue treating plates  113 ,  123  to insure sealing pressure is generated along and across and the same. This support geometry also allows the tissue treating plates  113 ,  123  to “fully seat” near the jaw tip, thus reducing the opportunity for flash to leak around and over the distal end of the tissue treating plates  113 ,  123  during molding. 
     Fins  112   a ,  122   a  are made from the same materials as the spacers  112 ,  122  mentioned above, namely, ceramic or other suitable material, e.g., PPA, Polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), Polyetherimide (PEI), polybenzimidazole (PBI) etc. Fins  112   a ,  122   a  are integrally associated, e.g., overmolded in single unitary construction, with spacers  112  and  122  or may be affixed in some other fashion, e.g., adhesive. As such, the fins  112   a ,  122   a  are typically overmolded at the same time as the spacers  112 ,  122  over the respective structural frames  111 ,  121 . 
     Jaw member  110  typically includes a fin  112   a  dimensioned having a height “H” of about 0.040 inches, a length “L” of about 0.040 inches, a width “W” of about 0.012 inches and a draft angle alpha “α” of about 0.5 degrees. Jaw member  120  typically includes a fin  122   a  dimensioned having a height “H” of about 0.050 inches, a length “L” of about 0.040 inches, a width “W” of about 0.012 inches and a draft angle alpha “α” of about 0.5 degrees. The lengths and drafts angles of the jaw members  110 ,  120  may change depending on the overall size of the jaw members for the particular sealing purpose, e.g., sealing vessels or sealing lungs, the desired length of the tapered distal ends  113   a ,  123   a  of the jaw members  110 ,  120 , etc. For example, draft angles in the range of 0° to about 10° are contemplated. 
     While several aspects of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. For example, the disclosure may incorporate a moving blade (not shown) instead of a thermal cutting element  130 . Obviously various components of the jaw members  120  and  110  would have to change to accommodate a moving blade, however, the overall purpose and spirit of the disclosure would remain the same. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular configurations. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 
     It will be understood that various modifications may be made to the aspects and features disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various aspects and features. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.