US 20070270679 A1
The invention provides a deflectable catheter capable of forming many variable radius spiral forms from a single, flexible, distal end section. In one aspect, the catheter employs a variable radius control wire to extend or deform a pre-formed loop structure into a three dimensional spiral-like form or geometry. The ability of a single catheter to create the multitude of shapes and sizes possible allows users to access a greater number of anatomical areas without changing the catheter during a procedure or treatment. In another aspect, the invention encompasses methods of producing deflectable variable radius catheters, where two or more regions of the catheter having common control wires are fused or formed onto one another.
1. A catheter comprising
a proximal section comprising a shaft and a control section at a proximal end, the control section operably connected to two or more bidirectional control wires and a variable radius control wire; and
a distal section comprising at desired points along its length at least one electrode, a connection point for the variable radius control wire, and a connection point for the at least two bidirectional control wires,
wherein engaging one or more of the bidirectional control causes a left to right motion in the distal section, and wherein engaging the variable radius control wire modifies the radius of the loop.
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19. A method of forming a desired three dimensional loop form in a catheter distal section, for positioning the catheter in an intracardial or epicardial area, comprising
providing a catheter having at least one control wire and at least one variable radius control wire;
inserting the catheter into a patient and advancing the catheter end to an epicardial or intracardial position;
engaging at least one control wire; and
engaging the variable radius control wire to modify the radius of a loop form.
20. The method of
21. The method of
22. A deflectable catheter comprising
a flexible distal end section having a tip or tip electrode and a proximal end having two or more actuators for controlling the shape of the distal end section;
a first control wire connected to a desired point in a central catheter shaft;
a variable radius control wire connected at or near the tip or tip electrode of the distal end section;
a central catheter shaft connecting the distal end section to the proximal end;
an actuator at the proximal end that engages the first control wire to produce a desired deflection in the distal end section; and
an actuator at the proximal end that engages the variable radius control wire to modify a loop form at the distal end.
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This application claims full priority benefit of prior U.S. Provisional application 60/800,851, filed May 17, 2006, the entire contents of which are hereby incorporated by reference.
The invention relates to catheters with improved deflectable and/or control characteristics, methods of using the catheters, and methods of producing them. In one aspect, for example, the invention encompasses a catheter design that allows a desired loop or partial loop to be formed at a distal end and the loop to be further controlled, for example, by contracting or extending into a spiral form or into a variable size and length, and also to be controlled in bilateral movement left to right without the bilateral movement affecting the contracting or extending, or vice versa. Thus, the invention provides improved control over the motion of the catheter. The catheter can also replace the use of multiple catheters having different distal end loop sizes with a single, flexible catheter capable of forming variable loop sizes along its length.
Deflectable or steerable catheters are used in various medical and surgical procedures, including ablation, such as arrhythmia ablation, mapping, such as cardiac mapping, and drug delivery, such as intracardial drug delivery. The steerable function can be accomplished by three modes of actions: straight translational movement along the direction of the catheter length; deflection of an end or distal section in one direction or in one plane; and turning of the catheter shaft to direct the deflected end toward the desired point. A control wire or pull wire positioned inside the catheter, usually connecting to the distal end, is used to direct the degree of deflection of the distal section. As known in the art, a catheter typically comprises a distal end that enters the body, and a proximal end that controls the movement or function at the distal end, the proximal end remaining outside the body. Deflection is generally within one plane, having only a curl or sweep profile. The control wire is operably connected to some type of a pulling mechanism, which is connected to a control device at the proximal end of the catheter shaft. The degree of pulling on the mechanism directs the movement of the control wire and thus the degree of deflection of the distal end of the catheter shaft.
In many cases, the control wire is located off of center relative to the catheter shaft. This allows a curve toward an intended deflection side. When the control wire is pulled, the catheter deflects toward the side of the catheter in which the wire is located. A bidirectional deflection is also possible, where two control wires are located on opposite sides of the catheter and the pulling on one control wire causes a deflection in one direction in a plane, and pulling on the other causes the opposite deflection in the same plane.
There are several known deficiencies with the use of existing steerable catheters. For example, the control in the direction of deflection is limited, and both the surface of the catheter and the interior space used for the control wire can operate inefficiently to cause unintended movement, or lack of movement, of the catheter tip. Furthermore, for those catheters designed to form a loop at the distal end, the size and shape of the loop is generally fixed by the length of the pull wire and/or the loop form is fixed within a single plane. Thus, catheters capable of improved control of the distal tip and those capable of forming a loop of variable sizes are desired in the art.
It is desirable to be able to direct catheter tips or distal sections of catheters in a variety of directions to accommodate numerous surgical procedures and anatomical features. In one aspect, the invention provides a deflectable catheter capable of forming one of many variable radius, spiral forms from a flexible distal end section. In one embodiment, the catheter employs a variable radius control wire to extend, contract, or deform a pre-formed loop structure, as a loop structure is typically produced from conventional, bidirectional deflectable catheter. The extended loop can essentially create a three dimensional, spiral-like form or geometry. The loop can also form a partial or complete circle. The ability of a single catheter to create the multitude of shapes and sizes possible allows a user to access a greater number of anatomical areas without changing the catheter or the size of the distal end during a procedure or treatment.
In a general aspect, the invention provides a catheter comprising a proximal section with a shaft and a control actuator at a proximal end, where the control actuator is connected to two or more bidirectional control wires. These wires can be engaged at the proximal end to produce a left to right motion in the distal end. The proximal section also comprises a second control actuator for separate control of a variable radius control wire. A distal section of the catheter comprises, at desired points along its length, at least one electrode, such as a sensing electrode or ablation electrode, and the distal section also comprises a connection point for the variable radius control wire, and a connection point for the at least two bidirectional control wires. The connection point for the variable radius control wire is typically in the loop section, while the connection point for the bidirectional control wires is proximal to the connection point for the variable radius control wire. Of course, the engagement of the control wire or wires and the engagement of the variable radius control wire can occur simultaneously to produce two independent planes of motion. The two independent planes of motion are allowed by use of two separate compression coils, one for each plane of motion, the motion in each plane is accomplished independently of motion in the other plane, and is done without affecting the position of the distal tip in the other plane.
The first compression coil can be in the inside diameter of the polymer shaft of the catheter, and extend from the proximal end of the shaft to the distal end of the straight portion of the shaft. The two bidirectional control wires are housed inside this first compression coil. Also housed inside the first compression coil is the second compression coil. While there can be a connection of the two compression coils at the proximal end of the second compression coil, the first and second compression coils are generally not connected, and may move independently of each other in the lateral direction. The variable radius control wire is housed in the lumen of the second compression coil. The second compression coil can run from the proximal end of the catheter to the tip electrode, or can run from a point on the first compression coil to a point inside the loop.
Various alternatives and specific embodiments of this general catheter are possible. For example, the catheter can further comprise a shape wire at the distal section, where the shape wire is preferably a Nitinol composition. The radius control wire can be connected to the distal end and the distal end can comprise a tip electrode. The catheter distal section can be composed of a variety of external, biocompatible coatings or coverings as known in the art, including a flexible polyether block amide, such as one of the many Pebax polymers available. More than one polymer composition can be used along the length of the distal section and at least two polymer compositions can have different hardness properties on the durometer A scale. When two bidirectional control wires and one variable radius control wire are used, the bidirectional control wires and the variable radius control wire can be housed separately within separate compression coils. The variable radius control wire is in a separate compression coil to avoid unintended left to right movement of the distal tip section of the kind preferably controlled by the bidirectional control wires when engaging the variable radius control wire to adjust the loop at the distal end. In a preferred embodiment, additional control of the desired loop form or spiral form can be achieved by using a flattened wire portion of the variable radius control wire, such that, for example, the most distal end and the end connecting to the tip or near the tip is a flattened wire. The use of flattened wire sections enables increased control over the loop.
In another general aspect, the invention provides a method of using the catheters and distal end sections of catheters. For example, the methods can be used to form a desired three-dimensional spiral form in a catheter distal section, and for positioning the catheter in an intracardial, epicardial, or pulmonary vein area. These methods can comprise inserting the catheter into a patient and advancing the catheter end to desired position. By engaging at least one control wire, one produces a desired loop form from a desired distal end structure, comprising the control wire and pull ring features noted above or throughout this disclosure. Engaging the variable radius control wire can extend the desired loop form into spiral form. Preferably, two bidirectional control wires are used that are together capable of causing a desired loop to form in the distal section of the catheter. A preferred method of using the catheters of the invention includes use in mapping or ablating the pulmonary vein ostium and surrounding areas of the heart, as in atrial fibrillation diagnosis and treatment procedures known in the art.
In another general aspect, the invention provides a deflectable catheter comprising a flexible distal end section, having a distal tip and optionally a tip electrode, and having a proximal end with two or more actuators for controlling the shape of the distal end section. A first control wire, and optionally more than one control wire, is connected to a desired deflection point at or near the end of a straight portion of the central shaft region, and a variable radius control wire is connected at or near the distal tip or tip electrode. As commonly known, the catheter can include a central shaft region that connects the distal end section to a handle and actuator at the proximal end. The shaft includes connections or continuing wire lengths so that a first, and optional additional control wire and the variable radius control wire can be operably attached to the actuators at the proximal end for the user to engage the wires. One of the actuators at the proximal end can engage a first control wire to produce a left to right motion at the end of the straight portion of the central shaft region. Then, another actuator at the proximal end that engages the variable radius control wire can reduce or extend the radius of the loop.
In another aspect, the invention provides a deflectable shaft and deflectable loop. The deflectable loop can be composed of an outer polymeric member with attached sensing electrodes, shape wire, control wire, tubing, and tip electrode. In a preferred embodiment, the polymers used at different points or sections of the catheter can differ, so that sections at the proximal end are made of a harder composition than the sections at the distal end. More particularly, a pattern of polymers having desired hardness, such as with the Shore D or durometer D hardness scale, can be selected for a particular section of the catheter to accommodate an expected or desired curvature during the use of the catheter.
Examples and preferred methods to produce the catheters of the invention and the final selection of internal tubing, sheathing, reinforcing braids or tubes, and heat-shrinking polymers to produce a desired inside and outside diameter are noted below.
A variety of catheters can be produced or used in accordance with the disclosure of this invention, including, without limitation, steerable catheters, introducers, RF or ultrasound ablation catheters, urologic catheters, drainage catheters, coronary sinus catheters, angiography catheters, catheters for locating pulmonary veins, intra-cardiac echo catheters, aortic bypass catheters, stent delivery or balloon catheters, imaging agent or contrast agent or drug or biological agent delivery catheters, EP or cardiac mapping catheters, sizing catheters, all in a wide variety of lengths and diameters. One of skill in the art is familiar with adapting the use of a deflectable or steerable catheter in a variety medical and surgical procedures.
The foregoing and other aspects, features, details, utilities, and advantages of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.
Throughout this disclosure, applicants refer to texts, patent documents, and other sources of information. Each and every cited source of information is specifically incorporated herein by reference in its entirety. Portions of these sources may be included in this document as allowed or required. However, the meaning of any term or phrase specifically defined or explained in this disclosure shall not be modified by the content of any of the sources.
The headings (such as “Brief Summary”) used are intended only for general organization of topics within the disclosure of the invention and are not intended to limit the disclosure of the invention or any aspect of it. In particular, subject matter disclosed in the “Related Art” includes aspects of technology within the scope of the invention and thus may not constitute solely background art. Subject matter disclosed in the “Brief Summary” is not an exhaustive or complete disclosure of the entire scope of the invention or any particular embodiment.
As used herein, the words “preferred,” “preferentially,” and “preferably” refer to embodiments of the invention that afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention and no disclaimer of other embodiments should be inferred from the discussion of a preferred embodiment or a figure showing a preferred embodiment. In fact, the nature of the devices and methods of the invention allow one of skill in the art to make and use the invention on many medical or surgical devices available or contemplated.
In one preferred embodiment, the invention comprises a catheter and the use of a catheter that in addition to bidirectional control wires to control movement, in one direction or another at a distal end or section, also comprises a control wire or wires for varying the radius of a formed loop or over a portion of a formed loop (variable radius control wire(s)). In practice, the invention advantageously allows the user to form desired three dimensional structures, such as a spiral structure, with a distal section of a catheter. This spiral structure can be used to access a number of tissue areas and anatomical features with improved control and accuracy compared to earlier devices and methods. In one preferred aspect, the spiral structure can be used to access the interior form of one or more pulmonary veins, such as during a pulmonary vein isolation (PVI) procedure. Thus, the invention specifically allows the formation of a three-dimensional spiral structure with a section of a medical device, particularly a catheter and even more particularly a catheter used in PVI mapping or ablation procedures.
With respect to intracardial, pulmonary vein and PVI procedures in general, the invention allows a single distal loop to form variable sizes in order to avoid the problem of using two or more catheters to reach desired anatomical features or electrophysiological elements in a patient because the loop can be moved left or right without changing the shape of the loop, and the size of the loop can also be changed without moving the loop left to right. The operator has increased control over the location of the loop. Thus, in one aspect, two independent types of motion are allowed by the use of a separate the left/right movement from movement controlling the shape or size of the loop movement, and the mechanisms controlling these two types of movement can be separated into two separate compression coils. For example, a first compression coil can be in the inside diameter of the polymer shaft of the catheter, and extend from the proximal end of the shaft to the distal end of the straight portion of the shaft. The two bidirectional control wires can be housed inside this first compression coil. Also housed inside the first compression coil is a second compression coil. The first and second compression coils need not be connected at any point of the shaft and allow independent movement of the control wires housed in them. Thus, the variable radius control wire can be housed in the lumen of the second compression coil. The second compression coil can run from the proximal end of the catheter to the tip electrode, or can run from a point on the first compression coil to a point inside the loop. In the past, multiple loops or distal structures may have been required during certain procedures because of individual variations in anatomy or size.
In another general aspect, the catheter comprises a compression coil, a pull ring assembly, a reinforced member of metallic, composite, or polymeric filament, and a flexible outer layer, preferably of one or more biocompatible polymers.
A number of polymers have been suggested for use in medical device and catheter applications, including: polyethylene; polyetherimide; polypropylene; polyetheretherketone (PEEK); polytetrafluoroethylene (PTFE) or Teflon (DuPont, Wilmington, Del.); Ultra High Molecular Weight (UHMW) polyethylene; high density polyethylene (HDPE); polyimide; polyaryletherketones; polyetheretherketones; polyurethane; polypropylene; oriented polypropylene; polyethylene; crystallized polyethylene terephthalate; polyethylene terephthalate; polyester; polyoxymethylene or Delrin (DuPont, Wilmington, Del.); polyamide-imide (PAI) or TORLON (Solvay Advance Polymers, Alpharetta, Ga.); polyoxymethylene (POM), acetal resin, or Delrin (DuPont, Wilmington, Del.); and polyvinylidene fluoride or Kynar (Atochem Corporation). One of skill in the art is familiar with selecting the appropriate polymer or polymer combinations to achieve the flexibility and lubricity properties desired. In some examples, flexible elostomers, such as polyether block amide—PEBA, such as Pebax®, a registered trademark of Atofina Chemicals, are a preferred polymer for use in the invention and methods especially for the external coating of the catheters, and especially in varying hardness according to the Durometer D or Shore D scale, known in the art.
In one embodiment, the invention comprises a deflectable shaft and a deflectable loop-forming distal section. The deflectable loop can comprise, consist, or consist essentially of an outer polymeric layer made of a 72 Durometer Pebax segment proximally and 40 Durometer Pebax segment distally. Any of the biocompatible Pebax polymers can be selected for use, but those with a hardness of 72 D, 55 D, and 40 D, are preferred. The loop section can also comprise polymers of varying hardness along its length, as depicted in the drawings. By varying the hardness along the lengths of the distal end or distal loop section, both the force required to manipulate through the actuators and the geometric structures the distal end section can eventually form can be controlled. The distal loop section can also comprise one or more electrodes or sensing electrodes along its length at desired points or intervals. The distal loop section can also comprise a shape wire composed of a shaped memory alloy, preferably NITINOL (an acronym for NIckel TItanium Naval Ordnance Laboratory). Other alloys or shaped memory alloys can be selected. In a preferred embodiment where a shaped wire is used, the shaped wire can be joined to a control wire or operably linked to a control wire, especially a flattened control wire or a flattened section of a control wire. The shaped wire, flattened control wire, and especially the combination of the flattened control wire and shaped wire enhance the control of the loop or curved form produced at the distal section. In another preferred embodiment, a PTFE or high lubricity polymer tubing or layer can surround the control wires, and/or the control wires and shaped wires. In another preferred embodiment, an FEP polymer tubing or layer can be used, and/or a polyimide polymer tubing or layer can be used. One of more layers of the polymers of tubing used can have desired imaging characteristics, so that the position, orientation, and the form of the distal loop section can be more easily visualized by one or more imaging techniques known or available in the art.
In a preferred aspect of any of the various embodiments disclosed, a distal end tip electrode is used. One of skill in the art is familiar with the selection of various electrodes for use in catheters, including, without limitation, sensing electrodes, ablation electrodes, RF delivery electrodes, ultrasound energy delivery probes, and others.
In another preferred aspect, at least one and preferably multiple sensing electrodes are mounted on the external polymer coating or tubing of the distal loop section. Each of the electrodes can be separately connected to a control and/or monitoring device, or multiple electrodes can be connected in series. The electrodes can be attached to the external surface by piercing holes, adhesive bonding, and subsequent stringing lead wires through the interior of the catheter shaft.
In any embodiment, including those where sensing electrodes are mounted on the external surface of the distal loop section, the invention optionally comprises a distal loop section having a pre-made form within the assembly, in order to direct the loop structure of form into a desired curve, loop, multiple loop, or curvilinear shape. As referred to herein, the term “loop” can be a simple curve, a multiple curve form, a compound curve form, a curvilinear form, an entire circle, a substantial part of an entire circle, or more than an entire circle. The drawings depict exemplary “loop” forms that can be produced during different aspects of the use of the catheters of the invention, but the drawings should not be taken as a limitation on the forms possible under this invention.
The tip electrode pull wire assembly is then inserted into the polymeric member from the distal end and inserted until the proximal end of the tip electrode is butted up to the polymer member.
Referring now briefly to the drawings,
The embodiments exemplified in the drawings will now be discussed in detail as some of the many examples possible under the invention. As shown in part of the invention detailed in
The inner or interior layer at the distal end can be constructed of polymeric material such as Polytetrafluoroethylene (PTFE), polyester, polyethylene, and similar biocompatible, flexible polymers and blends of the same. The preferred polymer material is PTFE, which provides a low coefficient of friction and high lubricity. Thermal or mechanical bonding can be used to attach the deflectable loop of
In methods to produce the catheters and catheter assemblies of the invention, the PTFE inner layer can be mounted on a mandrel with rectangular grooves running along the length of the mandrel and about 180 degrees apart, when the pull wires are desired at 180 degree separation. However, other configurations of the pull wires can be used.
As noted above, the outer layer is constructed of polymeric material, and can be similar to the inner layer or any combination of biocompatible polymeric compositions. Polymeric material used for this external or outer layer can preferably be one or more of the Pebax polymers available, but polyethylene, polyurethane, polyester, and blends can also be selected. Pebax is used for the particular design shown in
As shown in, for example, FIGS. 12A-F, the control of the deflection and loop forms possible in the distal section or assembly of the catheter during use is accomplished in part by one or more control wires. As noted above, a preferred control wire will have both a flattened or rectangular profile section and a round section, however, control wires of a variety of shapes and sizes can be selected for use. The preferred size of the control wire or wires ranges from about 0.005 to about 0.020 inches in diameter. In FIGS. 12A-F control wire attachment to one or more pull rings is detailed in various embodiments. Methods of attaching the wires to the pull rings are known in the art and include adhesives, brazing, and welding. A preferred attachment method is laser welding at the interior surface of the pull ring, and flattened section of control wires can preferably be laser welded to a pull ring. In use, the deflectable distal section or distal loop section can be articulated by pulling one or more control wires usually at an actuator in the handle section of the most proximal end of the catheter. Pulling the control wire or engaging the control wire by the actuator will cause the distal loop to deflect in a curve, as shown, for example, in
For example, to accomplish various curve forms or geometries and multiple deflections, a system of pull wires and pull ring combinations can be devised. As shown in
To achieve unidirectional or bidirectional loop actuation, one ring can be attached to the pull wires. This will articulate in one or both directions with symmetrical curve profile (
To achieve bidirectionality and asymmetry, two pull wires can be attached to two pull rings that are welded at different predetermined positions. Actuating one pull wire will achieve one curve profile while articulating the opposite pull wire will achieve a different curve profile (
To achieve bidirectionality in different plane and curve profiles, four (4) pull wires are attached to two pull rings at a predetermined location (
In another aspect of the invention, the use of multiple compression coils to isolate the movement or displacement of the various control wires can be incorporated into the design of the catheters of the invention. For example, in a preferred embodiment, a compression coil housing the variable radius control wire is separate from another compression coil housing the bidirectional control wire or wires. In a more particular embodiment, the proximal ends of both of these compression coils ends at the handle, at the proximal end, and can be joined by conventional techniques to the handle or its housing, such as adhesive bonding or UV bonding, either separately or together. The distal ends of the compression coils can end at different points along the catheter. A first compression coil can overlap a second, for example. The second compression coil can reside, to the extent it overlaps with the first, in the lumen of the first compression coil. The second compression coil can extend into the distal loop section, while the first compression coil ends proximal to that point.
In another preferred embodiment, the proximal end of the second compression coil bonds to the first compression coil, but thereafter proceed independently to the distal loop section.
A first compression coil can extend from the handle to a point in
The use of the catheter to form a three dimensional, variable radius and/or three dimensional or spiral form from any of the curve or loops forms noted here or possible with one or more control wires can be achieved, in one aspect, by providing a variable radius control wire. The variable radius control wire in essence exerts a force, such as pushing or pulling force, on one or more desired points on the distal section. In one alternative, the variable radius control wire exerts a pushing force from one proximal connection point on the distal section to a second distal connection point. Alternatively, the variable radius control wire exerts a pushing force simply at the distal end or one connection point at or near the distal end of the catheter and/or at the distal tip. Since the distal end has been locked into a curve or loop form by engaging the one or more control wires (such as engaging one or both of two bidirectional control wires), the pushing force causes the curve or loop to extend in another plane or dimension to essentially form a spiral or a form with spiral attributes. As used herein, the three dimensional spiral form or more generally “spiral form” refers to the result of the pushing force on a distal section of a pre-formed loop form of the distal section of a catheter. While a spiral generated from exerting a distal end section (or distal end) pushing force is preferably formed from a loop form as shown in
The images of
As shown in
The following are some examples of the preferred aspects of the invention.
In a pulmonary vein isolation procedure (PVI), a common step is mapping the electrophysiological characteristics using one or more sensing electrodes. The mapping procedure, as known in the art, combines positioning information through an imaging technique and electrical response information from electrodes. By providing a variable radius catheter, the mapping procedure can employ a single catheter that can vary its size and access points at or near the pulmonary veins, and at and through the pulmonary ostium, to produce a more precise map of the electrophysiology. For catheter ablation of atrial fibrillation (AF), a proper catheter positioning can be crucial to a successful treatment, and such success depends on knowledge of pulmonary vein (PV) anatomy and electrophysiology. By efficiently providing a single catheter to assess PV spatial orientation, ostial shape, and electrophysiology, the AF procedure is simplified and shortened.
The catheter of the invention with two bidirectional control wires for controlling movement of a distal loop section and with one variable radius control wire for further controlling, tightening, or extending a pre-formed structure in a third direction, for example, is used. The catheter is fed up the femoral vein, into the right atrium, introduced transseptally into the left atrium, and at least one bidirectional control wire is engaged to deflect the distal section in a desired direction. Mapping from the electrodes on the external surface of the catheter can begin at this point. To contact or record electrophysiology characteristics at points inside the pulmonary vein ostium, the loop can be adjusted to the desired size by engaging the variable radius control wire to a desired extent. A smaller radius and most distal end of the spiral, formed by engaging the variable radius control wire, can then be inserted into one or more pulmonary ostium to record electrical activity within the vein, which then can be used for mapping ostial ablation points. An ablation catheter having similar spiral form-generating mechanisms as discussed here can then be used to access and ablate the same ostial tissue, or a combined mapping and ablation catheter can be designed and used.
Although various embodiments of this invention have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention. It is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative only of particular embodiments and not limiting. All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the basic elements of the invention as defined in the following claims. The invention is not limited to any particular embodiment or example given here. Instead, one of skill in the art can use the information and concepts described to devise many other embodiments beyond those given specifically here.