Patent Application
20150359589
The present technology relates generally to intravascular neuromodulation and associated methods. In particular, several embodiments are directed to devices having generally helix-shaped support structures with spaced-apart proud portions for intravascular renal neuromodulation and associated methods.
The sympathetic nervous system (SNS) is a primarily involuntary bodily control system typically associated with stress responses. Fibers of the SNS innervate tissue in almost every organ system of the human body and can affect characteristics such as pupil diameter, gut motility, and urinary output. Such regulation can have adaptive utility in maintaining homeostasis or preparing the body for rapid response to environmental factors. Chronic activation of the SNS, however, is a common maladaptive response that can drive the progression of many disease states. Excessive activation of the renal SNS in particular has been identified experimentally and in humans as a likely contributor to the complex pathophysiology of hypertension, states of volume overload (such as heart failure), and progressive renal disease. For example, radiotracer dilution has demonstrated increased renal norepinephrine (“NE”) spillover rates in patients with essential hypertension.
Cardio-renal sympathetic nerve hyperactivity can be particularly pronounced in patients with heart failure. For example, an exaggerated NE overflow from the heart and kidneys of plasma is often found in these patients. Heightened SNS activation commonly characterizes both chronic and end stage renal disease. In patients with end stage renal disease, NE plasma levels above the median have been demonstrated to be predictive of cardiovascular diseases and several causes of death. This is also true for patients suffering from diabetic or contrast nephropathy. Evidence suggests that sensory afferent signals originating from diseased kidneys are major contributors to initiating and sustaining elevated central sympathetic outflow.
Sympathetic nerves innervating the kidneys terminate in the blood vessels, the juxtaglomerular apparatus, and the renal tubules. Stimulation of the renal sympathetic nerves can cause increased renin release, increased sodium (Na+) reabsorption, and a reduction of renal blood flow. These neural regulation components of renal function are considerably stimulated in disease states characterized by heightened sympathetic tone and likely contribute to increased blood pressure in hypertensive patients. The reduction of renal blood flow and glomerular filtration rate as a result of renal sympathetic efferent stimulation is likely a cornerstone of the loss of renal function in cardio-renal syndrome (i.e., renal dysfunction as a progressive complication of chronic heart failure). Pharmacologic strategies to thwart the consequences of renal efferent sympathetic stimulation include centrally acting sympatholytic drugs, beta blockers (intended to reduce renin release), angiotensin converting enzyme inhibitors and receptor blockers (intended to block the action of angiotensin II and aldosterone activation consequent to renin release), and diuretics (intended to counter the renal sympathetic mediated sodium and water retention). These pharmacologic strategies, however, have significant limitations including limited efficacy, compliance issues, side effects, and others. Recently, intravascular devices that reduce sympathetic nerve activity by applying an energy field to a target site in the renal blood vessel (e.g., via radio frequency ablation) have been shown to reduce blood pressure in patients with treatment-resistant hypertension.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure. Furthermore, components can be shown as transparent in certain views for clarity of illustration only and not to indicate that the illustrated component is necessarily transparent. For ease of reference, throughout this disclosure identical reference numbers may be used to identify identical or at least generally similar, analogous and/or complementary components or features.
The present technology is directed to apparatuses, and methods for achieving electrically- and/or thermally-induced renal neuromodulation (i.e., rendering neural fibers that innervate the kidney inert, inactive or otherwise completely or partially reduced in function) by percutaneous transluminal intravascular access. In particular, embodiments of the present technology relate to treatment devices (e.g., treatment catheters) having therapeutic assemblies with support structures that provide a pre-formed, generally helical shape with spaced-apart proud portions, such as steps, platforms or other structures protruding from the neighboring portions of the support structure. The therapeutic assemblies include neuromodulation elements (e.g., energy delivery elements, band electrodes, etc.) that can be associated, for example, with the proud portions of the treatment device. After being positioned in a target blood vessel of a human patient, a therapeutic assembly is transformable between a delivery configuration having a low-profile configured to pass through the vasculature and a deployed configuration in which the therapeutic assembly has a radially expanded shape (e.g., generally spiral/helical or coil) and in which the proud portions or steps maintain stable apposition between the neuromodulation elements and an inner wall of the target blood vessel (e.g., renal artery). Although it is the shape of the pre-formed support structure that tends to dominate or define the shape of the therapeutic assembly in the deployed configuration, other components of the assembly may also contribute to the shape of the deployed configuration. Therefore, the term “deployed configuration” can refer to the treatment device, the therapeutic assembly, the support structure, or other components that are actively or passively involved in the transformation between the delivery configuration and the deployed configuration.
The treatment devices may also be part of a system that can also include an energy source or energy generator external to the patient in electrical communication with the neuromodulation element(s). In operation, the neuromodulation element(s) are advanced intravascularly to a target blood vessel, such as the renal artery, along a percutaneous transluminal path (e.g., a femoral artery puncture, an iliac artery and the aorta, a radial artery, or another suitable intravascular path), and then energy is delivered to the wall of the target blood vessel via the neuromodulation element(s). Suitable energy modalities include, for example, electrical energy, radio frequency (RF) energy, pulsed electrical energy, or thermal energy. The treatment device carrying the neuromodulation element(s) can be configured such that the neuromodulation element(s) are in steady apposition with the interior wall of the target blood vessel when the therapeutic assembly is in the deployed configuration, e.g., radially expanded to have a spiral/helical shape. The proud portions or steps are offset with respect to adjacent and/or interposing regions of the support structure when the support structure is in the spiral/helical deployed configuration. The proud portions, for example, can protrude radially outward relative to neighboring portions of the support structure to contact the inner wall of the target blood vessel such that interposing segments of the support structure may have reduced contact force with, or be spaced radially inward and apart from the inner wall of the target blood vessel. The pre-formed spiral/helical shape of the deployed therapeutic assembly allows blood to flow through the assembly during therapy, which is expected to help prevent occlusion of the blood vessel during activation of the neuromodulation element(s), while the proud portions offset from the spiral/helical shape provide unobstructed or focused contact regions for the neuromodulation elements to enhance apposition with the inner wall of the target blood vessel.
Known energy-delivery catheter systems for inducing neuromodulation include one or more electrodes mounted on a positioning element, e.g. a balloon, a basket or a helical shaft that can itself contact the inner wall of the blood vessel and, in doing so, may compromise the desired contact between electrodes and the inner wall. For example, a portion of a positioning element near an electrode may contact an irregular surface of the interior wall of the blood vessel and thereby impair the integrity of or even prevent the contact between the electrode and the vessel wall. This can cause the measured impedance to be higher at such an electrode and result in an inconsistent lesion being formed on the interior wall of the blood vessel.
Several embodiments of the present technology have a support structure with proud portions that are offset radially outward with respect to adjacent and/or intervening portions of the support structure between the proud portions when the support structure is in a helical shape upon deployment. As such, neuromodulation elements (e.g., energy delivery elements, electrodes, etc.) mounted at the proud portions may more assuredly contact the interior wall of the blood vessel. In various embodiments, the offset of the proud portions may space the adjacent and/or interposing portions of the support structure inwardly apart from the interior wall. This reduced vessel wall contact by non-electrode portions of the therapeutic assembly is expected to increase the consistency of the electrical impedance measured between the neuromodulation elements and the surface of the interior wall of the blood vessel and thereby cause more consistent lesions to be produced as compared to conventional positioning elements that lack proud portions. For example, reliable radial and longitudinal contact of the electrodes with the inner wall of the target blood vessel may provide benefits, such as more reliable energy transmission, which may lower energy requirements and improve the accuracy of impedance and temperature measured at the inner wall of the target blood vessel. Therapeutic assemblies of the present technology also have a low-profile, collapsed delivery configuration in which the proud portions and associated neuromodulation elements are at least approximately in axial alignment with the longitudinal axis of the intervening portions of the low-profile support structure. As such, the present design allows for delivery of the treatment device through the vasculature in a low-profile guide catheter or delivery sheath.
Specific details of several embodiments of the technology are described below with reference to
As used herein, the terms “distal” and “proximal” define a position or direction with respect to the treating clinician or clinician's control device (e.g., a handle assembly). “Distal” or “distally” are a position distant from or in a direction away from the clinician or clinician's control device. “Proximal” and “proximally” are a position near or in a direction toward the clinician or clinician's control device.
Therapeutic assembly 100 may be transformed between the delivery and deployed configurations using a variety of suitable mechanisms or techniques (e.g., self-expansion). In one specific example, support structure 110 can include a pre-formed, self-expanding tubular structure that tends to take on the deployed configuration when unconstrained (e.g., by retracting a guidewire, a guide catheter, straightening sheath, etc.).
The proximal end of support structure 110 is carried by or affixed to distal portion 20 of elongated shaft 14. Catheter 12 may also include an atraumatic tip 112 at the distal end of support structure 110 to prevent intravascular trauma during delivery of the therapeutic assembly 100 to the treatment site. The distal end of catheter 12 may also be configured to engage another element of system 10 or catheter 12. For example, the distal end of catheter 12 may define a passageway for receiving guidewire 50 for delivery of the treatment device using over-the-wire (“OTW”) or rapid exchange (“RX”) techniques. Further details regarding such arrangements are described below with reference to
Neuromodulation element(s) 122 can be electrically coupled to energy source 30 via a cable 32, and energy source 30 (e.g., an RF energy generator) can be configured to produce a selected modality and magnitude of energy for delivery to the treatment site via neuromodulation elements 122 at proud portions 120 of support structure 110. As described in greater detail below, one or more supply wires (not shown) can extend along elongated shaft 14 or through a lumen in shaft 14 to therapeutic assembly 100 and supply the treatment energy to neuromodulation elements 122.
System 10 can further include a control mechanism 40, such as foot pedal or handheld remote control device, connected to energy source 30 to allow the clinician to initiate, terminate and, optionally, adjust various operational characteristics of energy source 30, including, but not limited to, power delivery. The remote control device 40 can be positioned in a sterile field and operably coupled to the therapeutic assembly 100, and specifically to neuromodulation elements 122, and can be configured to allow the clinician to activate and deactivate the energy delivery to neuromodulation elements 122. In other embodiments, the remote control device may be built into handle assembly 18.
The energy source or energy generator 30 can be configured to deliver the treatment energy via an automated control algorithm 34 and/or under the control of a clinician. For example, energy source 30 can include computing devices (e.g., personal computers, server computers, tablets, etc.) having processing circuitry (e.g., a microprocessor) that is configured to execute stored instructions relating to control algorithm 34. In addition, the processing circuitry may be configured to execute one or more evaluation/feedback algorithms 35, which can be communicated to the clinician. For example, energy source 30 can include a monitor or display 36 and/or associated features that are configured to provide visual, audio, or other indications of power levels, sensor data, and/or other feedback. Energy source 30 can also be configured to communicate the feedback and other information to another device, such as a monitor in a catheterization laboratory.
System 10 may be configured to provide monopolar or bipolar electric fields via neuromodulation elements 122. In embodiments configured to deliver monopolar electric fields, system 10 also includes a neutral or dispersive electrode 38 electrically connected to energy generator 30 and attached to the exterior of the patient, as shown in
System 10 can also include one or more sensors 22 located proximate to or within neuromodulation elements 122. For example, system 10 can include temperature sensors (e.g., thermocouples, thermistors, etc.), impedance sensors, pressure sensors, optical sensors, flow sensors, and/or other suitable sensors connected to one or more supply wires (not shown) that transmit signals from the sensors and/or convey energy to the therapeutic assembly 100.
Referring to
Referring to
In an alternate method step, guidewire 50 including distalmost portion 52 may be withdrawn completely from therapeutic assembly 100 to permit transformation of therapeutic assembly 100 into the deployed configuration while guidewire 50 remains within shaft 14. In yet another method step, guidewire 50 may be withdrawn completely from catheter 12. In any of the foregoing examples, the clinician can withdraw guidewire 50 sufficiently to observe transformation of therapeutic assembly 100 to the deployed configuration and/or until an X-ray image shows that distalmost portion 52 of guidewire 50 is at a desired location relative to therapeutic assembly 100 (e.g., at least partially withdrawn from the therapeutic assembly). In some methods, the extent of withdrawal of guidewire 50 can be based, at least in part, on the clinician's judgment with respect to the selected guidewire and the extent of withdrawal necessary to achieve deployment of the therapeutic assembly 100.
In one example, therapeutic assembly 100 terminates at an atraumatic tip 128 (
As best seen in
As shown in
Upon deployment, the pre-formed helical shape of support structure 110 provides proud portions 120 that are offset from the curvilinear axis CA1 in a direction radially outward from the central helical axis HA1 and in an orientation toward an interior wall of the target blood vessel. Referring to
The helix-shaped deployed configuration of support structure 110 is further illustrated in
As shown in
In some embodiments, proud portions 120 are both longitudinally and circumferentially offset from one another.
In one embodiment, support structure 110 can include a solid structural element, e.g., a wire, tube, coiled or braided cable. Support structure 110 may be formed from biocompatible metals and/or polymers, including polyethylene terephthalate (PET), polyamide, polyimide, polyethylene block amide copolymer, polypropylene, or polyether ether ketone (PEEK) polymers. In some embodiments, components of support structure 110 may be electrically nonconductive, electrically conductive (e.g., stainless steel, nickel-titanium alloy (nitinol), silver, platinum, nickel-cobalt-chromium-molybdenum alloy), or a combination of electrically conductive and nonconductive materials. In one particular embodiment, for example, support structure 110 can include a pre-shaped material, such as spring temper stainless steel or nitinol. Furthermore, in particular embodiments, support structure 110 may be formed, at least in part, from radiopaque materials that are capable of being fluoroscopically imaged to allow a clinician to determine if therapeutic assembly 100 is appropriately placed and/or deployed in the renal artery. Radiopaque materials may include, for example, barium sulfate, bismuth trioxide, bismuth subcarbonate, powdered tungsten, powdered tantalum, or various alloys of certain metals, including gold and platinum, and these materials may be directly incorporated into structural elements or may form a partial or complete coating on support structure 110.
As mentioned above, pre-shaped control member 116 may be used to impart a spiral/helical shape to support structure 110 having spaced-apart proud portions 120 in therapeutic assembly 100. In one embodiment, control member 116 can be a tubular structure comprising a nitinol multifilar stranded wire with a lumen therethrough and sold under the trademark HELICAL HOLLOW STRAND (HHS), and commercially available from Fort Wayne Metals of Fort Wayne, Ind. Control member 116 may be formed from a variety of different types of materials, may be arranged in a single or dual-layer configuration, and may be manufactured with a selected tension, compression, torque and pitch direction. The HHS material, for example, may be cut using a laser, electrical discharge machining (EDM), electrochemical grinding (ECG), or other suitable means to achieve a desired finished component length and geometry.
Forming control member 116 of nitinol multifilar stranded wire(s) or other similar materials is expected to provide a desired level of support and rigidity to the therapeutic assembly 100 without requiring additional reinforcement wire(s) or other reinforcement features within support structure 110. This feature is expected to reduce the number of manufacturing processes required to form therapeutic assembly 100 and reduce the number of materials required for the device.
In yet further embodiments, a stiffness of control member 116, and thereby support structure 110, can vary along the central longitudinal axis LA1 of support structure 110. For example, control member 116 at proud portions 120 can have a first stiffness and at adjacent portions 124 can have a second stiffness greater than the first stiffness. In various embodiments, variable stiffness along portions of control member 116 and/or support structure 110 could be provided using variations in a braid or weave pattern, coiled structures, woven structures and/or wire density as known by one of ordinary skill in the art of fabricating shaped devices. In such arrangements, proud portions 120 can be at least approximately in axial alignment (e.g., the offset resulting in an outer dimension less than 10% greater than the outer dimension D1) with longitudinal axis LA1 of support structure 110 in a delivery configuration (e.g., the stiffness of guidewire 50 can be greater than the stiffness of the shape memory material at proud portions 120) such that therapeutic assembly 100 can maintain a low-profile for delivery through a suitably-sized guide catheter (e.g., 6 Fr, 7 Fr, less than 8 Fr, etc.).
In one embodiment, flexible tube 114 provides an insulating layer or sleeve over control member 116 and energy supply wires 121 to further electrically isolate the material (e.g., nitinol) of support structure 110 (e.g., as shown in
In one embodiment, control member 116 and inner wall of tube 114 can be in intimate contact with little or no space therebetween (as best seen in
In other embodiments, control member 116 and/or other components of therapeutic assembly 100 may be composed of different materials and/or have a different arrangement. For example, control member 116 may be formed from other suitable shape memory materials (e.g., wire or tubing besides HHS or Nitinol, super elastic polymers, electro-active polymers) that are pre-formed or pre-shaped into the desired deployed configuration. Alternatively, control member 116 may be formed from multiple materials such as a composite of one or more polymers and metals.
In one embodiment, individual neuromodulation elements 122 can be electrodes configured to deliver energy (e.g., electrical energy, RF energy, pulsed electrical energy, non-pulsed electrical energy, thermal energy, etc.) across the wall of renal artery RA. In a specific embodiment, each neuromodulation element 122 can deliver a thermal RF field to targeted renal nerves adjacent the wall of renal artery RA. Referring to
Neuromodulation elements 122 are electrically connected to an external energy source (such as energy source 30,
In operation and referring to
After forming sufficient lesions or treatment zones to achieve neuromodulation, and in accordance with one method, therapeutic assembly 100 may be transformed back to the low-profile delivery configuration by axially advancing guidewire 50 relative to therapeutic assembly 100 (e.g., within lumen 111 of support structure 110). Once guidewire 50 is in position at the treatment site and therapeutic assembly 100 is in the low-profile delivery configuration, therapeutic assembly 100 can be pulled back with or over guidewire 50.
In the illustrated embodiment, the therapeutic assembly 200 further includes a control member 202 and an end piece, such as a tip 250, coupled to a distal region or portion 212a of support structure 210 and control member 202. Tip 250 can have a conical or bullet shape. For example, tip 250 can include a rounded distal portion for atraumatic insertion of therapeutic assembly 100 into a target blood vessel. In other embodiments, the end piece can be a collar or other type of cap. A proximal region or portion 212b of support structure 210 is coupled to and affixed to an elongated shaft 204 of the therapeutic assembly 200. Elongated shaft 204 defines a central passageway for passage of control member 202. Control member 202 may be, for example, a solid wire made from a metal or polymer. Control member 202 extends from elongated shaft 204 and is affixed to tip 250. Moreover, control member 202 slidably passes through elongated shaft 204 to an actuator in a handle assembly (not shown).
In this embodiment, control member 202 is configured to move distally and proximally through elongated shaft 204 so as to move tip 250 and distal region 212a of support structure 210 accordingly. Distal and proximal movement of distal region 212a respectively lengthens and shortens the axial length of the helix of support structure 210 so as to transform therapeutic assembly 100 between a delivery configuration (
Several suitable delivery methods are disclosed herein and discussed further below; however, one of ordinary skill in the art will recognize a plurality of methods suitable to deliver therapeutic assembly 100 to the treatment site and to deploy support structure 110 from the delivery configuration to the deployed configuration.
In the method step illustrated in
Image guidance, e.g., computed tomography (CT), fluoroscopy, intravascular ultrasound (IVUS), optical coherence tomography (OCT), or another suitable guidance modality, or combinations thereof, may be used to aid the clinician's positioning and manipulation of therapeutic assembly 100. For example, a fluoroscopy system (e.g., including a flat-panel detector, x-ray, or c-arm) can be utilized to accurately visualize and identify the target treatment site. In other embodiments, the treatment site can be determined using IVUS, OCT, and/or other suitable image mapping modalities that can correlate the target treatment site with an identifiable anatomical structure (e.g., a spinal feature) and/or a radiopaque ruler (e.g., positioned under or on the patient) before delivering catheter 12 and/or therapeutic assembly 100. Further, in some embodiments, image guidance components (e.g., IVUS, OCT) may be integrated with catheter 12, support structure 110 and/or run in parallel with catheter 12 to provide image guidance during positioning and removal of therapeutic assembly 100. For example, image guidance components (e.g., IVUS or OCT) can be coupled to at least one of therapeutic assembly 100 to provide three-dimensional images of the vasculature proximate the target site to facilitate positioning or deploying therapeutic assembly 100 within the target renal blood vessel.
Referring to
In operation (and with reference to
Features of the catheter device components described above and illustrated in
Various method steps described above for delivery and deployment of the therapeutic assembly components also can be interchanged to form additional embodiments of the present technology. For example, while the method steps described above are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.
Renal neuromodulation is the partial or complete incapacitation or other effective disruption of nerves innervating the kidneys. In particular, renal neuromodulation comprises inhibiting, reducing, and/or blocking neural communication along neural fibers (i.e., efferent and/or afferent nerve fibers) innervating the kidneys. Such incapacitation can be long-term (e.g., permanent or for periods of months, years, or decades) or short-term (e.g., for periods of minutes, hours, days, or weeks). Renal neuromodulation is expected to efficaciously treat several clinical conditions characterized by increased overall sympathetic activity, and in particular conditions associated with central sympathetic over-stimulation such as hypertension, heart failure, acute myocardial infarction, metabolic syndrome, insulin resistance, diabetes, left ventricular hypertrophy, chronic and end stage renal disease, inappropriate fluid retention in heart failure, cardio-renal syndrome, osteoporosis, and sudden death. The reduction of afferent neural signals contributes to the systemic reduction of sympathetic tone/drive, and renal neuromodulation is expected to be useful in treating several conditions associated with systemic sympathetic over activity or hyperactivity. Renal neuromodulation can potentially benefit a variety of organs and bodily structures innervated by sympathetic nerves.
Various techniques can be used to partially or completely incapacitate neural pathways, such as those innervating the kidney. The purposeful application of energy (e.g., electrical energy, thermal energy) to tissue by energy delivery element(s) or components such as those described in conjunction with the intravascular treatment assemblies above, can induce one or more desired thermal heating effects on localized regions of the renal artery and adjacent regions of the renal plexus, which lay intimately within or adjacent to the adventitia of the renal artery. The purposeful application of the thermal heating effects can achieve neuromodulation along all or a portion of the renal plexus.
The thermal heating effects can include both thermal ablation and non-ablative thermal alteration or damage (e.g., via sustained heating and/or resistive heating). Desired thermal heating effects may include raising the temperature of target neural fibers above a desired threshold to achieve non-ablative thermal alteration, or above a higher temperature to achieve ablative thermal alteration. For example, the target temperature can be above body temperature (e.g., approximately 37° C.) but less than about 45° C. for non-ablative thermal alteration, or the target temperature can be about 45° C. or higher for the ablative thermal alteration.
More specifically, exposure to thermal energy (heat) in excess of a body temperature of about 37° C., but below a temperature of about 45° C., may induce thermal alteration via moderate heating of the target neural fibers or of vascular structures that perfuse the target fibers. In cases where vascular structures are affected, the target neural fibers are denied perfusion resulting in necrosis of the neural tissue. For example, this may induce non-ablative thermal alteration in the fibers or structures. Exposure to heat above a temperature of about 45° C., or above about 60° C., may induce thermal alteration via substantial heating of the fibers or structures. For example, such higher temperatures may thermally ablate the target neural fibers or the vascular structures. In some patients, it may be desirable to achieve temperatures that thermally ablate the target neural fibers or the vascular structures, but that are less than about 90° C., or less than about 85° C., or less than about 80° C., and/or less than about 75° C. Regardless of the type of heat exposure utilized to induce the thermal neuromodulation, a reduction in renal sympathetic nerve activity (RSNA) is expected.
The above detailed descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.
From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Where the context permits, singular or plural terms may also include the plural or singular term, respectively.
Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the term “comprising” is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.
