Patent Application
20220323114
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
The present disclosure relates generally to robotic spinal surgery.
More particularly, this disclosure pertains to a stabilization apparatus for the detection and prevention of a loss of accuracy in robotic spinal surgery.
The use of robots in many surgical disciplines has become commonplace, yet a role for robots in spine surgery remained elusive due to the mobility of the spinal column and its intimate relationship with the spinal cord and nerve roots. The proximity of critical neural structures to the vertebrae necessitates millimetric accuracy, which has been difficult to achieve with the required consistency for practical clinical implementation.
While the first FDA approved spine robot was introduced in 2004, the use of robots in spine surgery remains limited. These robots represent the first generation of practically useful spinal robots, with their sole function being the accurate placement of implants into the bony spinal column.
There are, however, some fundamental challenges which must be overcome to grant the ease of use and dependability that will allow for widespread adoption of the robots in spinal surgery.
It is important to understand that these robots do not currently have the technology to track the location of the patient's spinal anatomy in real time. Consequently, at the beginning of surgery the robot is “registered” or familiarized with the patient's anatomy before surgery begins. Once this registration has been obtained, the robot will assume that the relationship between the robot and the patient's anatomy will not change for the duration of the surgery. As such, it is critical that the patient's spine not move in order to preserve the accuracy of the robot.
Foremost among the weaknesses of spinal robots is a loss of spatial accuracy leading to misplacement of implanted hardware in a patient's spine. Substantial resources have been dedicated to teaching the spinal robot how to match a 3D CT scan of the spine with the patient's spine on the operating room table, and this can now be done consistently with the required accuracy. Retaining that initial accuracy over the course of an entire surgical procedure, during which the spinal column is being heavily manipulated, remains an ongoing challenge.
Currently, spinal robots are either connected to the patient via a rigid attachment to the pelvis or function completely independently without any physical attachment to the patient's anatomy. Both of these operational paradigms have shortcomings: because the spine is articulated, it can move substantially relative to the pelvis making this method of attachment prone to an undetected loss of accuracy. In a system without any physical attachment at all, there is a complete reliance on optical navigation to detect a loss of accuracy without any physical attachment to detect or prevent such an error.
The maintenance of navigational accuracy is a seminal challenge in the development of spinal robotics. Detecting and preventing patient movement as a source of inaccuracy is a fundamental and unsolved challenge to establishing the dependability necessary for the widespread adoption of robotics in spine surgery.
In view of at least some of the above-referenced problems in conventional spinal surgery performed at least in part by a robot, an exemplary object of the present disclosure may be to provide a spinal stabilization apparatus that is configured to stabilize, detect, and prevent movement of the spine of a patient during spinal surgery.
An exemplary such apparatus may feature a three-point attachment frame, which may be affixed to the patient at both the proximal and distal ends of the spine to firmly triangulate the spinal column. The exemplary such apparatus may be affixed to the robot via a rigid connection. The exemplary such apparatus presents a straightforward solution prevents shifting of the spine in all three axes of space (e.g., x-, y-, and z-axes), thereby maintaining registration throughout surgery and preventing a loss of navigational accuracy. The exemplary such apparatus may further feature a strain gauge incorporated into the connection between the frame and the robot that allows for monitoring of the amount of force being applied to the patient. The robot (or an external device) may be programmed to activate an alarm state in the robot (or the external device) to thereby notify the surgeon of an impending loss of accuracy, and therefore prevent a potential catastrophic patient outcome.
The exemplary such apparatus may further feature a plurality of optical reference points (e.g., reflective spheres) positionable along the frame (e.g., at articulating joints of the frame). The reference spheres will piggyback on the robot's “optical navigation system” such that the robot will localize these references spheres in 3-dimensional space. Should there by a shift in the frame, the reference spheres will move relative to each other and the robot may be configured to immediately notify the surgeon that the has been a frame shift and a loss of accuracy.
In a particular embodiment, an exemplary spinal stabilization apparatus for preventing and detecting the unintended movement of a spine of a patient during spinal surgery performed at least partially by a robot is disclosed herein. The spinal stabilization apparatus may comprise a proximal attachment member, a distal attachment member, a first adjustable attachment arm, and a second adjustable attachment arm. The proximal attachment member may be configured to be positioned above a sacrum bone of the patient. The distal attachment member may be configured to be coupled to at least one vertebra of the spine of the patient. The first adjustable attachment arm may be configured to be coupled between the proximal attachment member and the distal attachment member. The first adjustable attachment arm may further be configured to be coupled to a first point on the pelvis or sacrum of the patient. The second adjustable attachment arm may be configured to be coupled between the proximal attachment member and the distal attachment member and extend away from the first adjustable attachment arm. The second adjustable attachment arm may further be configured to be coupled to a second point on the pelvis or sacrum of the patient.
In an exemplary aspect according to the above-referenced embodiment, the first and second adjustable attachment arms may be positioned bilaterally symmetrically or asymmetrically about the spine of the patient when the spinal stabilization apparatus is attached to the spine of the patient
In another exemplary aspect according to the above-referenced embodiment, the distal attachment member may be offset from the proximal attachment member by an offset distance. In accordance with this aspect, each of the first and second adjustable attachment arms may be longer than the offset distance.
In another exemplary aspect according to the above-referenced embodiment, the spinal stabilization apparatus may further comprise a first threaded post and a second threaded post. The first threaded post may be configured to couple the first adjustable attachment arm to an ilium portion of the first hip bone of the patient. The second threaded post may be configured to couple the second adjustable attachment arm to an ilium portion of the second hip bone of the patient.
In another exemplary aspect according to the above-referenced embodiment, the first threaded post may include a first end configured to be attached to the ilium portion of the first hip bone of the patient and a second end configured to be attached to the first adjustable attachment arm. In accordance with this aspect, the second threaded post may include a first end configured to be attached to the ilium portion of the second hip bone of the patient and a second end configured to be attached to the second adjustable attachment arm.
In another exemplary aspect according to the above-referenced embodiment, the first adjustable attachment arm may include a first arm proximal member, a first arm intermediate member, and a first arm distal member pivotally coupled together. The first arm proximal member may be configured to be coupled to the proximal attachment member. The first arm distal member may be configured to be coupled to the distal attachment member. In accordance with this aspect, the second adjustable attachment arm may include a second arm proximal member, a second arm intermediate member, and a second arm distal member pivotally coupled together. The second arm proximal member may be configured to be coupled to the proximal attachment member. The second arm distal member may be configured to be coupled to the distal attachment member.
In another exemplary aspect according to the above-referenced embodiment, the first arm intermediate member may be coupled between free ends of the first arm proximal member and the first arm distal member; and the second arm intermediate member may be coupled between free ends of the second arm proximal member and the second arm distal member
In another exemplary aspect according to the above-referenced embodiment, the first arm proximal member may include a first arm proximal member first end and a first arm proximal member second end. The first arm proximal member may be configured to be coupled to a first threaded post of the spinal stabilization apparatus between the first arm proximal member first end and the first arm proximal member second end. The first threaded post may be configured to be coupled to an ilium portion of the first hip bone of the patient. In accordance with this aspect, the second arm proximal member may include a second arm proximal member first end and a second arm proximal member second end. The second arm proximal member may be configured to be coupled to a second threaded post of the spinal stabilization apparatus between the second arm proximal member first end and the second arm proximal member second end. The second threaded post may be configured to be coupled to an ilium portion of the second hip bone of the patient.
In another exemplary aspect according to the above-referenced embodiment, the spinal stabilization apparatus may further comprise a plurality of threaded optical reference spheres. In accordance with this aspect, one threaded optical reference sphere of the plurality of threaded optical reference spheres may be positioned at each end of each of the first arm proximal member, the first arm distal member, the second arm proximal member, and the second arm distal member.
In another exemplary aspect according to the above-referenced embodiment, the first and second arm intermediate members may be telescopic in length.
In another exemplary aspect according to the above-referenced embodiment, each of the first arm proximal member, the first arm intermediate member, and the first arm distal member may be configured to be pivotally coupled together using a first plurality of fasteners and each of the second arm proximal member, the second arm intermediate member, and the second arm distal member may be configured to be pivotally coupled together using a second plurality of fasteners.
In another exemplary aspect according to the above-referenced embodiment, the spinal stabilization apparatus may further comprise a plurality of threaded optical reference spheres coupled along each of the first and second adjustable attachment arms. In accordance with this aspect, the plurality of threaded optical reference spheres may be configured to be monitored for determining if the spine of the patient moves during the course of the spinal surgery
In another exemplary aspect according to the above-referenced embodiment, the distal attachment member may be a spinous process clamp including a vertical post. The vertical post may be configured to couple to each of the first and second adjustable attachment arms.
In another exemplary aspect according to the above-referenced embodiment, the proximal attachment member may include a proximal robot attachment portion and the distal attachment member may include a distal robot attachment portion. In accordance with this aspect, one or more of the proximal robot attachment portion or the distal robot attachment portion may be configured to couple to a portion of the robot.
In another exemplary aspect according to the above-referenced embodiment, the spinal stabilization apparatus may further comprise at least one strain gauge configured to couple to one or more of the proximal robot attachment portion or the distal robot attachment portion. In accordance with this aspect, the at least one strain gauge may be configured to monitor sprain applied to the spinal stabilization apparatus by at least the robot such that impending movement of the spine of the patient is identifiable.
In another embodiment, a method of stabilizing a spine of a patient with a spinal stabilization apparatus for spinal surgery performed at least in part by a robot is disclosed herein. The method may comprise (a) coupling at least one threaded post of the spinal stabilization apparatus to one of an ilium portion of a hip bone or a sacrum bone of the patient; (b) coupling a clamp of the spinal stabilization apparatus to a spinous process of a vertebra of the spine of the patient; (c) positioning a proximal attachment member of the spinal stabilization apparatus above the sacrum bone of the patient; and (d) attaching first and second adjustable attachment arms of the spinal stabilization apparatus between the at least one threaded post and the clamp such that each of the first and second adjustable attachment arms extend away from each other on opposite sides of the spine of the patient.
In an exemplary aspect according to the above-referenced embodiment, step (d) of the method may further comprise coupling each of the first and second adjustable attachment arms to the proximal attachment member.
In another exemplary aspect according to the above-referenced embodiment, step (d) of the method may further comprise adjusting a positioning of a plurality of arm members of each of the first and second adjustable attachment arms to surround an area of surgical interest; and rigidly coupling the plurality of arm members of each of the first and second adjustable attachment arms together to stabilize at least a portion of the spine of the patient positioned between the clamp and the proximal attachment member and highlighted by the area of surgical interest.
In another exemplary aspect according to the above-referenced embodiment, the method may further comprise coupling a plurality of optical reference spheres to each of the first and second adjustable attachment arms such that one optical reference sphere of the plurality of optical reference spheres is positioned at each end of the plurality of arm members of the first and second adjustable attachment arms.
In another exemplary aspect according to the above-referenced embodiment, the method may further comprise coupling a plurality of optical reference spheres along each of the first and second adjustable attachment arms
Reference will now be made in detail to embodiments of the present disclosure, one or more drawings of which are set forth herein. Each drawing is provided by way of explanation of the present disclosure and is not a limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope of the disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment.
Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the present disclosure are disclosed in, or are obvious from, the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.
The words “connected”, “attached”, “joined”, “mounted”, “fastened”, and the like should be interpreted to mean any manner of joining two objects including, but not limited to, the use of any fasteners such as screws, nuts and bolts, bolts, pin and clevis, and the like allowing for a stationary, translatable, or pivotable relationship; welding of any kind such as traditional MIG welding, TIG welding, friction welding, brazing, soldering, ultrasonic welding, torch welding, inductive welding, and the like; using any resin, glue, epoxy, and the like; being integrally formed as a single part together; any mechanical fit such as a friction fit, interference fit, slidable fit, rotatable fit, pivotable fit, and the like; any combination thereof; and the like.
Unless specifically stated otherwise, any part of the apparatus of the present disclosure may be made of any appropriate or suitable material including, but not limited to, metal, alloy, polymer, polymer mixture, wood, composite, or any combination thereof.
Referring to
The spinal stabilization apparatus 100 may comprise a proximal attachment member 110, a distal attachment member 120, a first adjustable attachment arm 130, and a second adjustable attachment arm 150. The first and second adjustable attachment arms 130, 150 are configured to be attached between the proximal attachment member 110 and the distal attachment member 120 and are further configured to extend away from each other, for example, on opposite sides of the spine 12 of the patient 10 so as to not interfere with access to the spine 12 during surgery. The first and second adjustable attachment arms 130, 150 may surround the area of surgical interest 102 of the spine 12 of the patient 10 between the proximal attachment member 110 and the distal attachment member 120. In certain optional embodiments, the first and second adjustable attachment arms 130, 150 may be bilaterally symmetric about the spine 12 of the patient 10 when the spinal stabilization apparatus 100 is attached to the spine 12 of the patient 10.
The proximal attachment member 110 may be configured to be positioned above a sacrum bone 14 of the patient 10. The proximal attachment member 110 may include at least one arm attachment point 112. As illustrated, the at least one arm attachment point 112 includes a first arm attachment point 112A configured to be coupled to the first adjustable attachment arm 130 and a second arm attachment point 112B configured to be coupled to the second adjustable attachment arm 150. The at least one arm attachment point 112 may be a post, for example, a threaded post or the like. The first and second adjustable attachment arms 130, 150 may be coupled to the first and second arm attachment points 112A, 112B using fasteners as disclosed herein.
The distal attachment member 120 may be configured to be coupled to a spinous process 18 of a vertebra 16 of the patient 10. In certain optional embodiments (not shown), the distal attachment member 120 may be coupled to the spinous process of consecutive vertebrae. The distal attachment member 120 may also be referred to herein as a clamp 120. The distal attachment member 120 may be, for example, a spinous process clamp, as shown in
The distal attachment member 120 may be offset from the proximal attachment member 110 by an offset distance 104. Each of the first and second adjustable attachment arms 130, 150 may be longer than the offset distance 104.
The spinal stabilization apparatus 100 may further include at least one threaded post 170 configured to be coupled to one of the sacrum bone 14, a first hip bone 20 of the patient 10, or a second hip bone 30 of the patient 10. The first hip bone 20 may also be referred to herein as a left hip bone 20 and the second hip bone 30 may also be referred to herein as a right hip bone 30. As illustrated in
In certain optional embodiments, the first adjustable attachment arm 130 may be configured to be coupled to ilium portion 22 of the first hip bone 20 of the patient 10 using, for example, the first threaded post 170A. Likewise, the second adjustable attachment arm 150 may be configured to be coupled to ilium portion 32 of the second hip bone 30 of the patient 10 using, for example, the second threaded post 170B. In other optional embodiments (not shown), the at least one threaded post 170 may be coupled between the proximal attachment member 110 and the sacrum bone 14 of the patient 10.
Each of the at least one threaded post 170 may include a first end 172 and a second end 174. The first end 172 may be configured to be attached to one of the sacrum bone 14, the ilium portion 22 of the first hip bone 20, or the ilium portion 32 of the second hip bone 30. The second end 174 may be configured to be coupled to one of the proximal attachment member 110, the first adjustable attachment arm 130, or the second adjustable attachment arm 150.
The first adjustable attachment arm 130 may include a first arm proximal member 132, a first arm intermediate member 134, and a first arm distal member 136 configured to be pivotally coupled together. The first arm proximal member 132 may be configured to be coupled to the proximal attachment member 110. The first arm distal member 136 may be configured to be coupled to the distal attachment member 120. The first arm intermediate member 134 may be configured to be coupled between the first arm proximal member 132 and the first arm distal member 136.
Referring to
The couplings between the first arm proximal member 132, the first arm intermediate member 134, and the first arm distal member 136 may be defined by a first plurality of fasteners 138. The first plurality of fasteners 138 may comprise an exteriorly threaded shaft 138S and an interiorly treaded receiver 138R. The exteriorly threaded shaft 138S may comprise, for example, a threaded fastener such as a bolt, an all-thread shaft, or the like. As illustrated in
The second adjustable attachment arm 150 may include a second arm proximal member 152, a second arm intermediate member 154, and a second arm distal member 156 configured to be pivotally coupled together. The second arm proximal member 152 may be configured to be coupled to the proximal attachment member 110. The second arm distal member 156 may be configured to be coupled to the distal attachment member 120. The second arm intermediate member 154 may be configured to be coupled between the second arm proximal member 152 and the second arm distal member 156.
Referring to
The couplings between the second arm proximal member 152, the second arm intermediate member 154, and the second arm distal member 156 may be accomplished using a second plurality of fasteners 158. The second plurality of fasteners 158 may be identical to the first plurality of fasteners 138. The second plurality of fasteners 158 may comprise an exteriorly threaded shaft 158S and an interiorly treaded receiver 158R. The exteriorly threaded shaft 158S may comprise, for example, a threaded fastener such as a bolt, an all-thread shaft, or the like. As illustrated in
Each of the first arm proximal member 132 and the second arm proximal member 152 may be identical. Likewise, each of the first arm intermediate member 134 and the second arm intermediate member 154 may be identical. Finally, each of the first arm distal member 136 and the second arm distal member 156 may be identical.
The first threaded post 170A may be coupled to the first arm proximal member 132 between the first arm proximal member first end 132A and the first arm proximal member second end 132B. In certain optional embodiments, the first threaded post 170A may be coupled to the first arm proximal member 132 closer to the first arm proximal member first end 132A than to the first arm proximal member second end 132B. The second threaded post 170B may be coupled to the second arm proximal member 152 between the second arm proximal member first end 152A and the second arm proximal member second end 152B. In certain optional embodiments, the second threaded post 170B may be coupled to the second arm proximal member 152 closer to the second arm proximal member first end 152A than to the second arm proximal member second end 152B.
Referring to
The spinal stabilization apparatus 100 may further include a plurality of threaded optical reference spheres 190 configured to be coupled to along each of the first and second adjustable attachment arms 130, 150. The plurality of threaded optical reference spheres 190 may also be referred to herein as a plurality of optical reference spheres 190. Referring to
The arm members (e.g., the first arm proximal, intermediate, and distal members 132, 134, 136 and the second arm proximal, intermediate, and distal members 152, 154, 156) of each of the first and second adjustable attachment arms 130, 150 may be constructed of a rigid substrate, such as, for example, a metal alloy, or alternatively a composite material which includes rigid properties while also having radiolucent properties which will prevent the arm members from obstructing intraoperative x-rays. The certain optional embodiments, the proximal and distal attachment members 110, 120 may also be constructed of the same or similar material to that of the arm members.
Referring to
The spinal stabilization apparatus 100 may further include at least one strain gauge 106 configured to couple to one or more of the proximal robot attachment portion 114 or the distal robot attachment portion 126. The at least one strain gauge 106 may be configured to monitor a strain applied to the spinal stabilization apparatus 100 by at least the robot 40 such that impending movement of the spine 12 of the patient 10 can be determined.
In certain optional embodiments, the robot 40 may be attached to both the proximal robot attachment portion 114 and the distal robot attachment portion 126. Each of the proximal robot attachment portion 114 and the distal robot attachment portion 126 may include an interlocking tab (e.g., male/female joint, not shown) secured by a screw or other fastening means. The at least one strain gauge 106 may be integrated into the base of this tab (not shown) to accurately measure the forces being placed on the patient 10 relative to the robot 40 to detect a potential loss of accuracy.
The at least one strain gauge 106 and the plurality of threaded optical reference spheres 190 are two structures of the spinal stabilization apparatus 100 which may be utilized, for example, by the robot 40 (or some other external device) to detect a loss of accuracy (e.g., movement or impending movement of the spine 12 of the patient 10).
The at least one strain gauge 106 of the spinal stabilization apparatus 100 may be configured to transmit (wirelessly or wired) a constant voltage output to the base station (not shown) of the robot 40. This not only allows for user defined thresholds for an alarm to sound at the computer base station should the threshold value be exceeded, but also allows for recording of data and retrospective data review in cases in which a loss of accuracy is subsequently discovered after the surgery has been completed. The ability to retrospectively parse through this force data from many surgical cases will allow physicians to better understand the critical thresholds of force beyond which accuracy is lost and better predict a loss of accuracy in the future.
The plurality of threaded optical reference spheres 190 of the spinal stabilization apparatus 100 may piggyback on an infrared optical navigation system (not shown) of the robot 40. The infrared optical navigation system is the basis for localizing the articulating arm 42 of the robot 40 in 3D space. The plurality of threaded optical reference spheres 190 of the spinal stabilization apparatus 100 may be utilized by the robot 40 such that the infrared optical navigation system of the robot 40 can visualize the location of each of the first and second adjustable attachment arms 130, 150 in 3D space. The navigation system may then visualize and monitor the relationship between the first and second adjustable attachment arms 130, 150 as a 3D shape (e.g., the area of surgical interest 102), and sound an alarm if the spatial relationship between the plurality of threaded optical reference spheres 190 changes to suggest that a joint of the spine 12 of the patient 10 has shifted.
Referring to
In certain optional embodiments, step (d) of the method 200 may further include coupling each of the first and second adjustable attachment arms 130, 150 to the proximal attachment member 110.
In certain optional embodiments, step (d) of the method 200 may further include adjusting a positioning of plurality of arm members 132, 134, 136, 152, 154, 156 of each of the first and second adjustable attachment arms 130, 150 to surround an area of surgical interest 102 and rigidly coupling the plurality of arm members 132, 134, 136, 152, 154, 156 of each of the first and second adjustable attachment arms 130, 150 together to stabilize at least a portion of the spine 12 of the patient 10 positioned between the clamp 120 and the proximal attachment member 110, highlighted by the area of surgical interest 102. In other optional embodiments, the method 200 may further include coupling a plurality of optical reference spheres 190 to each of the first and second adjustable attachment arms 130, 150 such that one optical reference sphere of the plurality of optical reference spheres 190 is positioned at each end of the plurality of arm members 132, 134, 136, 152, 154, 156 of the first and second adjustable attachment arms 130, 150.
In certain optional embodiments, the method 200 may further include coupling a plurality of optical reference spheres 190 along each of the first and second adjustable attachment arms 130, 150.
In certain optional embodiments, the method 200 may further coupling the robot 40 to at least one of the clamp 120 or the proximal attachment member 110.
To facilitate the understanding of the embodiments described herein, a number of terms have been defined above. The terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity, but rather include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as set forth in the claims. The phrase “in one embodiment,” as used herein does not necessarily refer to the same embodiment, although it may.
Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
Although embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that various modifications can be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.
This written description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
It will be understood that the particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention may be employed in various embodiments without departing from the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.
All of the compositions and/or methods disclosed and claimed herein may be made and/or executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of the embodiments included herein, it will be apparent to those of ordinary skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.
The previous detailed description has been provided for the purposes of illustration and description. Thus, although there have been described particular embodiments of a new and useful invention, it is not intended that such references be construed as limitations upon the scope of this disclosure except as set forth in the following claims.
