Patent Publication Number: US-2021177525-A1

Title: Navigated instrument for use in robotic guided surgery

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Non-Provisional Application which claims priority to provisional application Ser. No. 62/947,688 filed on a Dec. 13, 2019, which is incorporated in its entirety herein. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to medical devices, and more particularly to an instrument for use with a robotic surgical system. 
     BACKGROUND 
     Position recognition systems for robot assisted surgeries are used to determine the position of and track a particular object in 3-dimensions (3D). In robot assisted surgeries, for example, certain objects, such as surgical instruments, need to be tracked with a high degree of precision as the instrument is being positioned and moved by a robot or by a physician, for example. 
     Position recognition systems may use passive and/or active sensors or markers for tracking the objects. In passive sensors or markers, objects to be tracked may include passive sensors, such as reflective spherical balls, which are positioned at strategic locations on the object to be tracked. With passive tracking sensors, the system then geometrically resolves the 3-dimensional position of the active and/or passive sensors based on information from or with respect to one or more of the infrared cameras, digital signals, known locations of the active or passive sensors, distance, the time it took to receive the responsive signals, other known variables, or a combination thereof. 
     These surgical systems can therefore utilize position feedback to precisely guide movement of robotic arms and tools relative to a patients&#39; surgical site. In surgical navigation, commonly tracked tools like a drill, tap or screwdriver are typically axially symmetrical. For example, a representation of a drill looks the same no matter how the drill bit is rotated. The tracking array for such tools may be mobile in its rotational coordinate about the tool since the rotational position of the tool does not need to be monitored. Therefore, marker arrays for tracking these common tools are designed with the array on a sleeve that is free to rotate about the tool. The user may reposition the array about the tool shaft as necessary to keep it facing toward the tracking cameras while using the tool. 
     However, it is sometimes necessary to track a tool that is not symmetrical, such as a curved curette or a delivery device for an interbody spacer. In such cases, the system must track the full rigid body position of the tool so that it can properly update the image of the tool overlaid on anatomy, showing, for example, which direction the curve or cutting surface of the curette faces. For these tools and instruments, different methods must be used to find the tracking array&#39;s orientation relative to the tool in all directions including rotation. 
     SUMMARY 
     An instrument for use in a navigated surgical procedure, the instrument includes a proximal portion, a distal portion and a shaft extending therebetween. An angled instrument tip is positioned at an end of the distal portion of the instrument. A first tracking array is coupled to the proximal portion of the instrument and a surveillance array is coupled to the proximal portion of the instrument. The tracking array includes a plurality of tracking markers, and is configured to rotate with respect to a central axis of the instrument. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in a constitute a part of this application, illustrate certain non-limiting embodiments of inventive concepts. In the drawings: 
         FIGS. 1A, 1B and 1C  are views of a surgical instrument according to one embodiment of the present invention. 
         FIGS. 2A and 2B  illustrates an embodiment of a surgical instrument with an array having adjustable positions. 
         FIGS. 3A and 3B  illustrates the surgical instrument with centerline markers and offset markers for use with a surgical robotic system according to some embodiments; 
         FIG. 4  illustrates another embodiment of the surgical instrument having multiple offset markers and center line markers. 
         FIGS. 5A, 5B, 5C, and 5D  illustrate yet another embodiment of a surgical instrument that allows rotation of an array by use of a cam mechanism. 
         FIGS. 6A, 6B, 6C, and 6D  show another embodiment of a surgical instrument that uses a hinged cam mechanism to allow rotation of an array. 
         FIGS. 7A and 7B  illustrate another embodiment of a surgical instrument that uses multiple cam mechanisms for rotation of an array. 
         FIGS. 8A-8D  illustrates yet another embodiment of a surgical instrument according to the present disclosure. 
         FIG. 9  illustrates another embodiment of a surgical instrument with a plurality of tracker arrays. 
         FIG. 10  illustrates yet another embodiment of a surgical instrument in which the array is configured to swivel about central axis of the surgical instrument. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the description herein or illustrated in the drawings. The teachings of the present disclosure may be used and practiced in other embodiments and practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
     The following discussion is presented to enable a person skilled in the art to make and use embodiments of the present disclosure. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the principles herein can be applied to other embodiments and applications without departing from embodiments of the present disclosure. Thus, the embodiments are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the embodiments. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of the embodiments. 
     In surgical navigation, it is very important that a tool&#39;s tracker marker template be accurate so that a tracked tool and/or tracked robot end effector is correctly localized relative to the anatomy. A method is whereby a sequence of simple and rapid test movements using a navigated tool and a tracked rigid guide tube, such as the guide tube of a surgical robot, can fully calibrate a tool that was initially not calibrated. The calibrated tool will have its shaft coincident with one coordinate axis, the markers facing toward a pre-defined direction, and the origin offset by a pre-defined distance from the origin of the tracked rigid guide tube. 
     Surgical navigation uses an optical tracking system where two or more cameras detect reflective or active markers on tools and track the 3D coordinates of the markers through stereophotogrammetry. As discussed in the previous embodiments, surgical tools are equipped with rigidly mounted arrays of 3 or more reflective or active markers, and the tracking system uses best-fit algorithms to match the detected marker locations to stored templates of ideal marker locations. In this way, the system can determine which tool or tools are in view, and where the tools, as rigid bodies, are located in the coordinate system of the cameras. Virtual landmarks can also be found. For example, from the tracked locations of markers that are mounted on a tool&#39;s handle, the system finds the location of the tool shaft and tip in camera space. Once tool locations are known relative to the cameras and registration has been performed to align the coordinate system of the cameras to the coordinate system of the medical image, it is possible to graphically display tool locations overlaid on the medical images. 
     Several factors can influence the accuracy of surgical navigation. The array of optical markers that is attached to the tool is poorly defined or can become displaced, either in whole or in part, causing errors because the detected markers positions are shifted or do not fit the stored marker template well. Other factors included inconsistent lighting and poor viewing angles of markers. In surgical navigation, errors in tracking of poorly-calibrated navigated tools can be manifested as “wander” of the graphic of the tool when the user rotates the tool within a rigid tube. That is, the display of a tool that is rotated within a rigid tube should not move since the tool is spinning about its axis without translating or bending. If the display does in fact wander, it confirms that the tracked location of the tool&#39;s array does not match the stored template for the tool. 
     Now turning to  FIGS. 1A-1C , there is shown a tracking array coupled to an instrument that optimally allows the tracking of the instrument according to one embodiment. When a tracking array is rigidly mounted to a tool, the array is designed so that it is pointing optimally toward the cameras while the tool is held in the most often used position. 
       FIGS. 1A, 1B, and 1C  shows a navigated tool  10  having a proximal portion  12 , a middle portion  14 , and a distal portion  16 . The distal portion  16  of the navigated tool  10  in this embodiment is provided with a curved tip  18 . A shaft  20  extends from the curved tip  18  to the proximal portion  12 . At the proximal portion of the tool  18 , there is a handle  22  and a tracking array  24 . The tracking array  24  is configured to be rotated with respect to the longitudinal axis of the navigated tool  10 . The adjustable tracking array  24  also includes a calibration dial  26  positioned on an upper surface of the tool  10 . The tracking array  24  is also configured to be positioned at any rotational position and may be locked into position and identified by a locking position as marked on the calibration dial  26 . When the tracking array  24  is locked in a particular orientation relative to the handle  22 , the user may enter or the system detects the rotational coordinate and the system shows a representation of the tool  10  overlaid on the anatomy. As shown in  FIG. 1B  and  FIG. 1C , the tracking array  10  is locked in position  5  (center) or position  6  (right) to allow tracking cameras to maintain a line of sight for tracking the full motion of the tool  10 . The tracking array  24  in the present embodiment illustrates a plurality of markers  25 . It should be noted that in other embodiments, it is contemplated that the tracker array  24  may having a more than additional or less markers than shown in the current embodiment. The tracker array  24  may also be configured as a different shape than illustrate in  FIGS. 1A-1C . 
     In another embodiment as shown in  FIGS. 2A and 2B , a multi-positional array system  30  includes a proximal portion  32 , a distal portion  34  and a shaft  36  extending from the proximal portion to the distal portion  34 . The distal portion  34  includes a curved tip in one embodiment, but include any type of tip that is suitable for a surgical procedure. The proximal portion also includes a handle  38  and a rotatable tracking array  40 , and a fixed marker  42 . The fixed marker  42  may be used as an additional tracking marker as a means of automatically identifying the system  30  position relative to the tracking array  40 . This additional fixed marker  42  must be offset from the center of rotation of the tracking array (center shaft of the tool) to detect array position. 
       FIGS. 2A and 2B  also shows an embodiment of an array  40  that is rotationally adjustable. The tool array  40  is rotatably movable relative to the handle  38  and shaft  36 . A single fixed marker  42  mounted to the central shaft detects the rotational position of the tracking array relative to the shaft, allowing correct tracking and graphical representation of the entire tool including the curved tool tip. Although in the present embodiment the fixed marker  42  is shown in a particular offset location, it is contemplated in other embodiments, that the fixed marker  42  may be configured in type of offset position relative to the tool and tracking array. Also, it the present embodiment, the tracking marker  42  is positioned in a offset position from the upper surface of the tool, it is contemplated in other embodiments that the offset tracking marker  42  may be positioned laterally with respect to the tool  30 . 
     Now turning to  FIGS. 3A and 3B , an instrument  50  having a handle  52 , a shaft  54  and a plurality of tracking markers is shown. The instrument  50  includes at least two centerline markers  56  and at least two offset markers  58 . The offset markers  58  extend a distance away from the central axis of the instrument  50 . The offset markers  58  are also provided with shields  60 . The centerline markers  56  and offset markers  58  are rigidly attached to the instrument  50 . The centerline markers  56  and offset markers  58  are provided with features allowing it to be viewed from a wide range of angles. The offset markers  58  are at different longitudinal coordinates along the centerline, allowing the system to distinguish between the offset markers  58  when only one is visible by the distance from the centerline markers  56 . Alternately, the offset markers  58  could be at different radial distances offset from centerline but at the same longitudinal coordinate to allow them to be distinguished. The thin flat shield  60  behind each offset marker hides the marker from view and prevents visual overlap with other markers or parts of the tool when the tool is rotated away from the cameras. Although in the present embodiment, only two offset markers and centerline makers are shown, it is contemplated that a plurality of either centerline and/or offset makers may be utilized to determine the position of the instrument. 
     In another embodiment, a part of one offset marker may be visible farther from the cameras due to partial obstruction from its shield and the whole of another offset marker is visible closer to the cameras. The system can utilize the larger detected  2 D “blob” (high contrast region) size in deciding which of the two offset markers to use in calculations to get the most accurate navigation. Alternately, the system may also use calculations for both sets of 3 markers (two centerline markers plus offset marker  1  or two centerline markers plus offset marker  2 ) to determine the tip location of the instrument. 
     In another embodiment as shown in  FIG. 4 , there is provided an instrument  60  that utilizes three offset markers  62  at 120° separation, ensuring that at least one of the offset markers is fully visible to both cameras at any orientation. The instrument  60  also includes at least two colinear markers  64  positioned on the central axis of the instrument. 
       FIGS. 5A and 5B  shows an instrument  70  with a proximal portion  72  and a distal portion  74 . The proximal portion includes a tracking array  76  and a single cam mechanism  78  that causes an tracked marker  80 , which is positioned on a spring-loaded piston  82 , to move toward or away from a central shaft of the instrument  70  when the tracking array  76  is rotated about the shaft. The cam mechanism  78  is an offset circular or oblong shaped element on which a spring-loaded plunger  82  presses. This mechanism  78  causes the plunger  82  to move inward and outward by varying amounts as the array orientation is adjusted relative to the instrument tip as shown in  FIG. 5C  and  FIG. 5D . After calibrating the angle of the tracker array relative to marker&#39;s  80  linear position, by tracking the offset of the additional marker, the system can determine the orientation of the instrument  70 . As the instrument tip is moved and angled as shown as about 135 degrees counterclockwise as shown in  FIG. 5C , the marker  80  is offset to position D 1 . If the instrument tip is angled to about 5 degrees clockwise as shown in  FIG. 5D , the marker  80  is moved to offset position D 2 . As shown in  FIGS. 5C and 5D , the cam mechanism  78  is configured to provide information to the tracking system about the orientation of the tip relative to the instrument. In this embodiment, the tracker array  76  is provided with 4 markers, it is contemplated in other embodiments, additional or less markers may be used to navigate the instrument. 
       FIGS. 6A-6D  show an instrument  82  having a proximal portion  84  and a distal portion  86 . The proximal portion  84  includes a tracker array  88  that includes a plurality of trackers  90 . The proximal portion  84  also includes a single cam mechanism  92  coupled to a handle assembly  94  of the instrument  82 . The single cam mechanism  92  is coupled to the upper surface of the handle assembly  94  of the instrument. The cam mechanism  92  is also coupled to a tracking marker  96 . Tracking marker  96  is positioned on a hinged, spring-loaded arm  98  and configured to move toward or away from the central shaft of the instrument when the tracker array  88  is rotated about the shaft. As further illustrated in  FIGS. 6C and 6D , the spring loaded arm  98  is configured to swivel in varying directions allowing for the tracked marker  96  to be visualized by the camera system at different locations. After calibrating angle of tracker array  88  relative to tracker marker  96  position, by detecting the offset of the marker  96 , the system can determine the orientation of the instrument. 
     With either a linear or hinged mechanism, the moving position of the tracker marker can be detected relative to the positions of the rest of the markers in the tracking array and this information used to determine the orientation of the instrument tip relative to the tracking array. Then, as the surgeon uses the instrument, the tracker array may face toward the cameras while positioning the instrument appropriately to perform surgical work, and the system can continuously track the instrument position while also showing a correct graphical representation of the instrument, including its asymmetrical tip. 
     Now turning to  FIGS. 7A and 7B , a system for unambiguously defining the instrument tip orientation of an instrument through a full 360 degree range using two cam mechanisms is shown. As show in  FIGS. 7A and 7B , a surgical instrument  100  having a proximal portion  102  and a distal portion  104 . The distal portion  104  is provided with an angled end or tip  106  for performing surgical procedures. The proximal portion  102  is provided with a first tracking array  108 . The first tracking array  108  is provided with a plurality of tracking markers  110 . Each of the plurality of tracking makers  110  are spaced apart from one another and configured to be detected by a camera system. The proximal portion  102  of the instrument  100  also includes a handle assembly  112 . The proximal portion  102  also includes a second tracker array  114  having at least one tracker marker  116 . The second tracker array  114  is coupled to the proximal portion  102  via a first cam mechanism  118  and a second cam mechanism  120 . The first cam mechanism  118  is configured to enable the second tracker array  114  to moved vertically with respect to the longitudinal axis of the instrument  100 . The second cam mechanism  120  is configured to enable the second tracker array  114  to be moved horizontally with respect to the longitudinal axis of the instrument  100 . As each cam mechanism controls the position of tracking marker  116 , the positions of the marker  116  can be identified relative to the tracking array  108 . 
     In another embodiment, the second cam mechanism may be configured to shift the whole assembly of the first cam mechanism, thereby, the first cam mechanism may shift the marker  116  inward and outward along a piston toward or away from the tracker array  108 , whereas the second cam mechanism could shift the marker  116  longitudinally up or down in the direction of the instrument relative to the tracker array  108 . 
     Now turning to  FIGS. 8A-8D , another embodiment for determining the rotational positioning of an instrument  130  is provided.  FIGS. 8A-8D  illustrates a proximal portion of the instrument  130 . The instrument  130  includes a first tracker array  132  and a second tracker array  134  with a tracker marker  135 . Tracker marker  135  is attached to a hinged cam assembly  136 . The hinged cam assembly  136  includes a lever arm  138  attached to the cam mechanism  140 . As the instrument is rotated, the tracker marker  135  is moved rotationally and angularly with respect to the central longitudinal axis of the instrument  130 . As a result, the tracker marker  135  along with the first tracker array  132 , is tracked by the camera system allowing the instrument tip to accurately tracked during surgical procedures. 
     In yet another embodiment,  FIG. 9  illustrates an instrument  150  having multiple tracking arrays  152 . Each of the tracking arrays  152  is configured with a plurality of tracking markers  154 , with each tracking marker  154  having a shield  156 . The tracking arrays  152  are deployed about the center axis of the instrument  150 . In one embodiment, the system would select for tracking only the 3 or more markers closest to the cameras and in best view of the cameras. The tracking arrays  152  in this embodiment provide 3 markers each however it is contemplated in other embodiments to have additional or less markers for each tracking array  152 . The tracking arrays  152  are also configured to be detected by a camera system from all angles. 
       FIG. 10  shows an embodiment in which surgical instrument  160  includes a tracker array  162  that is capable of rotating with respect to the longitudinal axis of the instrument. The tracker array  162  includes plurality of markers  164  and a surveillance marker  166  positioned on a central portion of the tracker array  162 . The surveillance marker  166  is configured to rotated with respect to the tracker array  162  and is configured to identify the array position relative to the instrument tip. The surveillance marker  166  is mounted directly to the tracker array  162  face on the central portion of the tracker array  162 . In other embodiments, it is contemplated that the surveillance marker  166  is configured to rotated and translated with respect to the instrument  160 . 
     Now turning to  FIG. 11 , a tracking system and method of performing a procedure to optimize the tracking of markers is provided. When an optical tracking system tracks the markers on a tool or instrument, it performs a comparison of the detected markers to the known stored marker template for that tool or instrument using computational methods. Other important landmarks of the tool or instrument such as its tip and tail are designed to be in known locations in the template coordinate system. During any tracking frame, using computational methods, the system transforms the coordinates of any landmark defined within the template coordinate system to camera space based on the tool&#39;s detected markers in that frame. 
     In one embodiment of the invention, the positioning of physical features of the tool within the coordinate system of the marker template can serve to re-define the tool template during a simple calibration procedure. These features of the tool are defined such that it is exactly aligned with and positioned along the Cartesian coordinate (X,Y,Z) axes according to standards used for registration. The navigated tool or instrument includes a shaft that is aligned along the Z axis, with a tail that is configured to be in a more positive position than the tip of the tool or instrument. The marker array coupled to the instrument is aligned at a rotational position about the Z axis at which the marker&#39;s plane normal is aligned in a X direction. The tool or instrument is positioned longitudinally along the Z axis with its Z origin (Z=0) at the location where the tool bottoms out on the guide tube. 
     Using a tool or instrument as provided, the following sequences may be applied in one embodiment of the invention. The system may record the end effector markers or calibration tool markers to establish where an inserted tool bottoms out relative to the end effector guide tube  170 . Next, the navigated tool is inserted until it bottoms out in the tube. Then the tool or instrument may be swiveled back and forth about its shaft between 45-90° while keeping the tool or instrument bottomed out. 
     The data is recorded from these steps in tracking the instrument and used to create an updated tool or instrument template file using the following algorithm. The helical axis of motion in the camera space from the frames of data recoding the swiveling of the instrument is recoded. The axis represents the functional center of the tool or instrument shaft. Next, the system transforms the helical axis into alignment with the Z-axis and these transformations are applied to each data set. Then the instrument or tool is translated along the Z-axis unit it bottoms out and matches the bottom out point of the end effector. Next, the tool is rotated to position the marker array in the positive X direction. After these transformations are applied to the point set, the marker positions in the tool template file are replaced with the marker position in the new coordinate system. 
     It is also contemplated that software may “repair” the calibration of a tool if it is discovered during usage that the calibration is off. In one embodiment, the user would indicate to software that a repair is being initiated, possibly by pressing a button or otherwise activating a feature that sets a flag indicating that the repair should occur on the next tool coming into close proximity with the end effector guide tube. When a tool is bottomed out in the guide tube, the origin of the tool and the origin of the guide tube should be nearly coincident if the guide tube&#39;s origin is also defined as the tube&#39;s center and upper rim, or the point where any tool entering it bottoms out. 
     In the first step of a repair workflow, it is noted that it should be specified which markers belong to the tool&#39;s array. Providing the current (damaged) template for the purpose of sorting and matching incoming markers is one possible way to specify the desired markers since each frame can be compared to the damaged template and only markers that are within a tolerance of matching the template pattern can be automatically selected. Alternately, a software interface could take a static shot and markers belonging to the tool could be manually marked on a software interface; software monitors and tracks the markers as they move. In another embodiment, the system may utilize elements that strobe in a known pattern, allowing markers to be indexed and always stored in the same order for each frame. In such systems, the list indices of markers belonging to the tool could be specified. 
     In later steps, the helical axis of motion (HAM) is calculated. Computational methods used for calculating the finite HAM or approximating the instantaneous HAM from tracked marker data are applied, and better accuracy is achieved with larger angular step sizes. 
     In some embodiments, instead of repairing an existing template, the swivel method can be used to successfully create an accurate tool marker template without any starting template. Therefore, such a method could construct an accurate marker template for a tool with markers arbitrarily glued, bolted or otherwise secured to its tool shaft as long as the tool bottoms out at a known position and has a central shaft that can be swiveled. If the length of a tool from the location where it bottoms out (its origin) to the tip and the tool&#39;s shaft diameter is provided, then all of the critical information about the tool for safe navigation is specified. A generic tool appearing overlaid on the anatomy as a cylinder of specified diameter with the tip offset at the specified distance from the origin could be overlaid on the anatomy to represent the tool and accurately visualize the anatomy intersected by the tool. 
     Incorporating various methods of tracking the array as well as asymmetric tip orientation and allowing the updating of the CAD model in the software is more accurate in two main orientations, and depending on array pattern in respect to the camera, allows the surgeon to track in a wider variety of positions. Tracking such as this is especially helpful during tracking where the CAD model orientation updates automatically without UI input from the surgeon. 
     In the above-description of various embodiments of present inventive concepts, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of present inventive concepts. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which present inventive concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     When an element is referred to as being “connected”, “coupled”, “responsive”, or variants thereof to another element, it can be directly connected, coupled, or responsive to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected”, “directly coupled”, “directly responsive”, or variants thereof to another element, there are no intervening elements present. Like numbers refer to like elements throughout. Furthermore, “coupled”, “connected”, “responsive”, or variants thereof as used herein may include wirelessly coupled, connected, or responsive. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Well-known functions or constructions may not be described in detail for brevity and/or clarity. The term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements/operations, these elements/operations should not be limited by these terms. These terms are only used to distinguish one element/operation from another element/operation. Thus a first element/operation in some embodiments could be termed a second element/operation in other embodiments without departing from the teachings of present inventive concepts. The same reference numerals or the same reference designators denote the same or similar elements throughout the specification. 
     As used herein, the terms “comprise”, “comprising”, “comprises”, “include”, “including”, “includes”, “have”, “has”, “having”, or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. Furthermore, as used herein, the common abbreviation “e.g.”, which derives from the Latin phrase “exempli gratia,” may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. 
     Although several embodiments of inventive concepts have been disclosed in the foregoing specification, it is understood that many modifications and other embodiments of inventive concepts will come to mind to which inventive concepts pertain, having the benefit of teachings presented in the foregoing description and associated drawings. It is thus understood that inventive concepts are not limited to the specific embodiments disclosed hereinabove, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. It is further envisioned that features from one embodiment may be combined or used with the features from a different embodiment(s) described herein. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described inventive concepts, nor the claims which follow. The entire disclosure of each patent and patent publication cited herein is incorporated by reference herein in its entirety, as if each such patent or publication were individually incorporated by reference herein. Various features and/or potential advantages of inventive concepts are set forth in the following claims.