US20190254733A1 - Systems and methods to enhance radial spray from a catheter - Google Patents

Abstract

The present disclosure relates generally to the field of medical devices and, in particular, the present disclosure relates to methods and devices to enhance radial spray from a catheter, such as devices with flow distribution elements for a radial spray catheter, including for radial cryospray catheters.

Description

PRIORITY
• This application claims the benefit of priority under 35 USC § 119 to U.S. Provisional Patent Application Ser. No. 62/633,121, filed Feb. 21, 2018, which is incorporated by reference herein in its entirety and for all purposes.
FIELD
• The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to methods and devices to enhance radial spray from a catheter. Devices with flow distribution elements for a radial spray catheter, including radial cryospray catheters, are disclosed.
BACKGROUND
• Various catheters are used within different body lumens for different applications, including to deliver fluids, as a diagnostic or treatment option, to the body lumen. The fluid may be a liquid, a gas, or a mixture of both a liquid and a gas. The delivery may involve spraying the fluid on the wall of the body lumen. For purposes of delivering a catheter through an endoscope within a body lumen, in some cases, involving multiple radial apertures, the efficacy and/or efficiency of the procedure may be dependent on how uniformly the flow may be distributed among the apertures. For example, fluid may tend to flow to the endmost apertures at the distal end of a catheter more so than flowing out of more proximal apertures, creating a non-uniform distribution of flow.
• As an example, cryosurgery is a procedure in which diseased, damaged or otherwise undesirable tissue (collectively referred to herein as “target tissue”) is treated by focal delivery of a cryogen under pressure, which may be a cryogen spray. These systems are typically referred to as cryoablation systems, cryospray systems, cryospray ablation systems, cryosurgery systems, cryosurgery spray systems and/or cryogen spray ablation systems. As typically used, “cryogen” refers to any fluid (e.g., gas, liquefied gas or other fluid known to one of ordinary skill in the art) with a sufficiently low boiling point (i.e., below approximately −153° C.) for therapeutically effective use during a cryogenic surgical procedure. Suitable cryogens may include, for example, liquid argon, liquid nitrogen and liquid helium. Pseudo-cryogens such as carbon dioxide and liquid nitrous oxide that have a boiling temperature above −153° C. but still very low (e.g., −89° C. for N₂O) may also be used.
• During operation of a cryospray system, a medical professional (e.g., clinician, technician, medical professional, surgeon etc.) directs a cryogen spray onto the surface of a treatment area via a cryogen delivery catheter. The medical professional may target the cryogen spray visually through a video-assisted device or endoscope, such as a bronchoscope, gastroscope, colonoscope, or ureteroscope. Cryogen spray exits the cryogen delivery catheter at a temperature ranging from 0° C. to −196° C., causing the target tissue to freeze or “cryofrost.”
• Body lumens (e.g., the esophagus, trachea, intestines, etc.) may be treated with cryoablation via radial spray from a catheter. However, as noted above, distributing flow of cryogen mixtures through a catheter central lumen, such as liquid nitrogen and its vapor, to multiple apertures of a catheter may be difficult due to the higher density and, by extension, momentum of the liquid component of cryogen when compared to the gaseous component of cryogen in the cryogen mixture. The gaseous portions of the cryogen mixture may easily flow out of the more proximal apertures (e.g., radial apertures) while the liquid portion of the cryogen may continue to flow axially to the more distal apertures, resulting in a flow imbalance. A flow imbalance among rows of apertures may limit the uniformity and effective length of a cryogen catheter's spray volume and coverage area.
• Various advantages therefore may be realized by the devices, systems and methods of the present disclosure for enhancing radial spray from catheters utilizing flow distribution elements.
SUMMARY
• The present disclosure in its various embodiments includes methods and devices to enhance radial spray from a catheter. Various embodiments may include devices for a radial spray catheter and/or a radial cryospray catheter. Various embodiments may be used with cryosurgery systems configured to enhance radial cryospray with different elements to improve flow distribution. Devices for a radial spray catheter, including radial cryospray catheters and plugs, may emit spray more efficiently and may result in more effective treatment for targeted tissue. Devices for radial cryospray catheters or other devices, or radial cryospray catheters or other devices, with flow distribution elements, may contribute to more uniform distribution of the spray and efficiently orienting the spray laterally (normal to the target) from the apertures, whereas devices without a flow distribution element may have an undesirable substantial axial component to the spray velocity or direction, or both.
• The present disclosure in various embodiments includes devices and methods of use for enhanced radial spray from a catheter. Enhanced spray may be used to more efficiently delivery fluids to treatment areas to provide, among other benefits, a more productive coverage of spray at treatment sites. Various embodiments have flow distribution elements, either as a component or accessory for use with a catheter or as an integral part of spray catheters.
• In one aspect of the present disclosure, a device for a radial spray catheter may include a body that may have a longitudinal axis, a proximal end, a distal end, a mid-portion extending therebetween, and an exterior radial surface. A central lumen may extend within the body along the longitudinal axis from the proximal end of the body into at least the mid-portion of the body. One or more apertures may be distributed about the exterior radial surface of the body. A flow distribution element may be in fluid communication with the central lumen and the one or more apertures. The one or more apertures may be radial openings, or slot openings, or both. The central lumen may extend through the distal end of the body and may be configured to accept a medical instrument. The central lumen may transition from a smaller diameter to a larger diameter between the proximal end of the body and the mid-portion of the body. The proximal end of the body may be configured to be mated with a distal end of the catheter. The proximal end of the body may be mated by being a continuous extension of the distal end of the catheter, bonded to the distal end of the catheter, or removably coupled to the distal end of the catheter.
• In another aspect of the present disclosure, the flow distribution element may include a diffuser element that is coaxial with the central lumen and may face proximally along the longitudinal axis of the body. The diffuser element may include a cone with a cone apex that faces proximally along the longitudinal axis of the body. The flow distribution element may include a plurality of lumens fluidly connecting the central lumen with a plurality of the one or more apertures. Each lumen may extend distally within the body parallel to the longitudinal axis and may then transition along a radial wall of the body that may be perpendicular to the longitudinal axis to a corresponding aperture. The body may be ellipsoid-shaped with the major axis of the ellipsoid shape coinciding with the longitudinal axis of the body. Each lumen may extend distally within the body parallel to the longitudinal axis and may then transition along a radial wall of the body that is perpendicular to the exterior radial surface of the body to a corresponding aperture. The plurality of lumens may include discrete components that are configured to be nested together to form the body. The lumens may extend distally within the body parallel to the longitudinal axis and may then transition gradually along a curve to corresponding apertures. The central lumen may transition from the smaller diameter to the larger diameter at an angle of about 30 degrees from the longitudinal axis in the direction of the large diameter. A porous sheath or porous rings may be about the exterior radial surface of the body covering the apertures. The flow distribution element may include a plurality of independent lumens comprising elongate tubes, and each tubular lumen may be associated with an independent aperture. Each tubular lumen may have a proximal portion that extends distally within the body parallel with the central lumen and along a curve to a radial portion of the tubular lumen that may be aligned with the associated aperture. The tubular lumens may be aligned in concentric radial circles at the proximal portion. The lumens radially closer to the longitudinal axis of the body may extend farther distally at the radial portion than the lumens radially farther from the longitudinal axis of the body. The flow distribution element may include a porous body within the mid-portion of the body. The porous body may be configured to be gradually less permeable along the longitudinal axis of the body from a proximal end of the porous body to a distal end of the porous body. The porous body may be gradually more permeable from the longitudinal axis of the body in a direction toward the exterior radial surface of the body.
• In another aspect of the present disclosure, the flow distribution element may include a distribution lumen that extends from the central lumen to the distal end of the body and is in fluid communication and substantially coaxial with the central lumen. The distribution lumen may have sections in the direction of the distal end along the longitudinal axis of the body that change in inner diameter and may each include at least one of the apertures. The change in inner diameter may become larger from section to section in the direction of the distal end or may become smaller from section to section in the direction of the distal end, or some combination thereof. One or more of the apertures may have a diameter that becomes larger from section to section in the direction of the distal end, or becomes smaller from section to section in the direction of the distal end, or some combination thereof. The change in inner diameter may be inversely proportional to a change in wall thickness of the body from section to section along the distribution lumen. The diameter of the exterior radial surface of the body along the distribution lumen may be constant. A section in the proximal portion of the distribution lumen may have a smaller diameter than the central lumen. The flow distribution element may have a distribution lumen that extends from the central lumen to the distal end of the body and is in fluid communication with the central lumen. The distribution lumen may include a plurality of the apertures along the longitudinal axis. A spring may be within the distribution lumen having a distal component associated with the distal end of the body and a proximal component associated with an oscillator body. The oscillator body may oscillate in the distribution lumen with flow pushing against a restoring force of the spring to distribute the flow to the apertures. The spring may be a pair of magnets with one magnet of the pair as the distal component of the spring and the other magnet of the pair as the proximal component and the oscillator body. Like poles of the magnets may face one another that act as the restoring force of the spring. The spring may have the distal component attached to the distal end of the body and the proximal component attached to the oscillator body. A volume of gas may be compressed distally behind the oscillator body that acts as the restoring force of the spring. The oscillator body may have a diffuser element having a larger diameter toward the distal end of the body and a smaller diameter of the diffuser element pointing against a direction of the flow from the proximal end of the body.
• In another aspect of the present disclosure, the flow distribution element may include a distribution lumen within the body extending from the central lumen. A rod may be rotatably disposed within the distribution lumen along the longitudinal axis of the body. A turbine may be axially disposed about the rod. A multilumen member may be disposed about the rod, distal to the turbine and extending along the rod. Each lumen of the multilumen member may have an exposed radial portion that longitudinally coincides with a respective one of a plurality of radial rows of the apertures. Each lumen of the multilumen member may terminate at a substantially radial wall that is adjacent distally to the respective one of the radial rows of apertures for each lumen.
• In another aspect of the present disclosure, a device for a radial spray catheter may include an elongate member having a longitudinal axis, an open proximal end, a distal end, and plurality of lumens extending therebetween in fluid communication with a flow distribution element. The flow distribution element may be disposed about the elongate member and may include a plurality of longitudinally adjacent annular chambers. Each chamber may have a proximal end, a distal end, a central lumen extending therethrough that receives the elongate member, and a plurality of radial apertures about an outer surface of the chamber. Each one of the plurality of lumens of the elongate member may be dedicated to a respective each one of the plurality of chambers and may have at least one dedicated supply aperture in fluid communication therewith. Each lumen of the elongate member may terminate at the at least one dedicated supply aperture associated with its respective annular chamber. The elongate member may be mated to a distal end of a catheter by being a continuous extension of the distal end of the catheter, bonded to the distal end of the catheter, or removably coupled to the distal end of the catheter.
• In another aspect of the present disclosure, a device for a radial spray catheter may include an elongate body configured to be inserted into a distal end opening of a catheter. The body may have a longitudinal axis, a proximal end, and a distal end. A flow distribution element may extend at least partially between the proximal and distal end of the body and may include a backstop at the distal end of the body. The flow distribution element may include a plurality of fins extending radially from the longitudinal axis of the elongate body. The fins may be configured to engage an inner surface of the catheter. The backstop may have a surface perpendicular to and facing the distal end opening of the catheter when the elongate body is inserted into the catheter. The surface may be longitudinally offset from the distal end opening of the catheter in a distal direction forming a radial aperture around the opening. The flow distribution element may include a plurality of fins extending along the elongate body and arranged in a helical pattern that widens radially further from the longitudinal axis of the elongate body as the fins extend to the backstop. The backstop may be configured to engage an inner surface of the catheter. The backstop may have a concave surface facing the distal end opening of the catheter. The flow distribution element may include a diffuser element extending proximally from the concave surface against a direction of flow from the opening of the catheter. The concave surface may be offset from the distal end of the elongate body, creating a radial aperture around the opening.
BRIEF DESCRIPTION OF THE DRAWINGS
• Non-limiting embodiments of the present disclosure are described by way of example with reference to the accompanying figures, which are schematic and not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:
• FIG. 1 illustrates an isometric view of a cryosurgery system in accordance with an embodiment of the present disclosure.
• FIG. 2 illustrates a radial spray tip of a catheter in accordance with an embodiment of the present disclosure.
• FIG. 3A illustrates a left view of a device with a flow distribution element including lumens in accordance with an embodiment of the present disclosure.
• FIG. 3B illustrates a cross-sectional view of the embodiment inFIG. 3A.
• FIG. 3C illustrates a left view of a device with a flow distribution element including lumens in accordance with an embodiment of the present disclosure.
• FIG. 4A illustrates a left view of a device with a flow distribution element including lumens in accordance with an embodiment of the present disclosure.
• FIG. 4B illustrates a cross-sectional view of the embodiment ofFIG. 4A.
• FIG. 4C illustrates a left view of a device with a flow distribution element including lumens and a sheath in accordance with an embodiment of the present disclosure.
• FIG. 4D illustrates a left view of a device with a flow distribution element including lumens and a scalloped outer surface in accordance with an embodiment of the present disclosure.
• FIG. 5A illustrates a left, quarter-cross-sectional view of a device with a flow distribution element including a plurality of tubular lumens in accordance with an embodiment of the present disclosure.
• FIG. 5B illustrates a cross-sectional view the embodiment ofFIG. 5A.
• FIG. 6 illustrates a cross-sectional view of a device with a flow distribution element including a porous body in accordance with an embodiment of the present disclosure.
• FIG. 7A illustrates a perspective, cross-sectional view of a device with a flow distribution element including a distribution lumen that has a change in diameter in accordance with an embodiment of the present disclosure.
• FIG. 7B illustrates a perspective, cross-sectional view of a device with a flow distribution element including a distribution lumen that has a change in diameter in accordance with an embodiment of the present disclosure.
• FIG. 8A illustrates a left view of a device with a flow distribution element including a distribution lumen with an oscillator body attached to a spring in a first position in accordance with an embodiment of the present disclosure.
• FIG. 8B illustrates a left, cross-sectional view of the embodiment ofFIG. 8A with the spring in a second position.
• FIG. 9A illustrates perspective view of a device with a flow distribution element including a distribution lumen with a rotatable turbine in accordance with an embodiment of the present disclosure.
• FIG. 9B and 9C illustrate an axial, cross-sectional view of the embodiment ofFIG. 9A in a first and second position, respectively.
• FIG. 10A illustrates a perspective view of a device with a flow distribution element including a distribution lumen with a plurality of annular chambers in accordance with an embodiment of the present disclosure.
• FIG. 10B is a substantially rear view of the embodiment ofFIG. 10A.
• FIG. 10C is a perspective view of the distribution member ofFIGS. 10A and 10B.
• FIG. 10D is a perspective view of the annular chamber ofFIGS. 10A and 10B.
• FIG. 11 is a perspective view of a device with a flow distribution element including an insert for a catheter in accordance with an embodiment of the present disclosure.
• FIG. 12A is a perspective view of a device with a flow distribution element including an insert for a catheter in accordance with an embodiment of the present disclosure.
• FIG. 12B is a left view of the embodiment ofFIG. 12A.
• FIG. 13 is a right, cross-sectional view of a device with a flow distribution element including a backstop having a concave surface in accordance with an embodiment the present disclosure.
DETAILED DESCRIPTION
• The present disclosure is not limited to the particular embodiments described. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting beyond the scope of the appended claims. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. Although embodiments of the present disclosure are described with specific reference to radial cryospray systems for use within the upper and lower GI tracts and respiratory system, it should be appreciated that such systems and methods may be used in a variety of other body passageways, organs and/or cavities, such as the vascular system, urogenital system, lymphatic system, neurological system and the like.
• As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used herein, specify the presence of stated features, regions, steps elements and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and/or groups thereof.
• As used herein, the conjunction “and” includes each of the structures, components, portions, or the like, which are so conjoined, unless the context clearly indicates otherwise, and the conjunction “or” includes one or the others of the structures, components, portions, or the like, which are so conjoined, singly and in any combination and number, unless the context clearly indicates otherwise.
• As used herein, the term “distal” refers to the end farthest away from the medical professional when introducing a device into a patient, while the term “proximal” refers to the end closest to the medical professional when introducing a device into a patient. As used herein, “diameter” refers to the distance of a straight line extending between two points and does not necessarily indicate a particular shape.
• The present disclosure generally provides methods and devices to enhance radial spray from a catheter. Various embodiments may include devices to enhance spray for a radial spray catheter and/or a radial cryospray catheter.
• For example, various embodiments of devices for enhanced spray, described here or otherwise, within the scope of the present disclosure, may be used with cryosurgery systems configured with flow distribution elements to improve uniformity of flow distribution. Exemplary cryosurgery systems in which the present disclosure may be implemented include, but are not limited to, those systems described in U.S. Pat. Nos. 9,301,796 and 9,144,449, and U.S. patent application Ser. Nos. 14/012,320 and 14/869,814, each of which are herein incorporated by reference in their entirety. In various embodiments, features and advantages of distributing fluid through flow distribution elements may be realized with a lumen running the length of the element that accommodates a medical instrument extending therethrough. Such elements may be implemented with features throughout the disclosure of co-owned U.S. Provisional Patent Application having Attorney Docket number 8177.0040, filed concurrently herewith, which is incorporated by reference herein in its entirety and for all purposes.
• In one embodiment of a cyrospray delivery system configured for devices to enhance cryospray from a catheter, as illustrated inFIG. 1, acatheter102 is connected to acryotherapy console100 at acatheter interface104. Thecatheter102 may be used with an endoscope for delivery into a patient. An image received at the lens on the distal end of the endoscope may be transferred to a monitoring camera which sends video signals via a cable to themonitor108, where the procedure can be visualized. Built-in software and controls in the console allows the medical professional to control delivery of cryogen from the tank through thecatheter102 via afoot petal106. Thecatheter102 may have an insulatedportion110 and adistal end112.
• As an example of the fluid mechanics of cryospray formation and supply, with reference to the system illustrated inFIG. 1, as cryogen (e.g., liquid nitrogen) travels from the tank to the proximal end ofcryogen delivery catheter102, the liquid warms and starts to boil, resulting in cool gas emerging from thedistal end112 ofcatheter102. The amount of boiling in thecatheter102 depends on the mass, surface area, and thermal capacity ofcatheter102. When the liquid nitrogen undergoes phase change from liquid to gaseous nitrogen, additional pressure is created throughout the length ofcatheter102. This is especially true at a solenoid/catheter junction, where the diameter of the supply tube to the lumen ofcatheter102 decreases, e.g., from approximately 0.25 inches to approximately 0.070 inches, respectively. The lumen of thecatheter102 may have a diameter, e.g., ranging between 0.030 and 0.115 inches. In other embodiments, the lumen may have another range of diameter depending on what is suitable for a particular application. In an alternate embodiment, gas boiling inside thecatheter102 may be reduced even greater by the use of insulating materials such as PTFE, FEP, Pebax, and the like, or by surrounding the catheter with a substantially evacuated lumen to help reduce the rate of heat transfer.
• With further reference toFIG. 1, as an example, thecatheter102 is connected to aconsole100. Theconsole100 contains the tank that supplies the cryogen. Theconsole100 may include precooling and defrost features. Theconsole100 and/orcatheter102 include valving and plumbing to deliver the cryogen under pressure, e.g., delivering low pressure to thedistal tip112 of thecatheter102. There may be sensors within theconsole100 and/or thecatheter102 to measure the temperature of the cryogen and/or the tissue. There may be a feedback loop for metered control of cryogen dosing. A pedal106 may be used to control the cryogen delivery, or the cryogen delivery may be timed for a predetermined dosage. Thedistal tip112 may be open-ended and/or include radial apertures. Theconsole100 may include software and/or hardware with safety features. Theconsole100 may include an interactive user interface. Theconsole100 may include control settings for a cryospray therapy procedure. Theconsole100 may include cryospray procedure profiles for pre-determined delivering of cryospray.
• With reference toFIG. 2, an exemplary cyrospray catheter in accordance with an embodiment of the present disclosure is illustrated. Thecatheter202 is placed within a patient such that thedistal end212 is in proximity to the target tissue. A medical professional may visualize placement of thedistal end212 of thecatheter202 via a camera in an endoscope and/or through fluoroscopy. The markingbands208 may be visualized using the camera and/or may be radiopaque for visualization with a fluoroscope. With thedistal end212 in position, the medical professional may introduce cryogen into thecatheter202. When the cryogen reaches thedistal end212 ofcatheter202 it exits thedistal tip204 and/or theradial apertures206 as a cyrospray towards the target tissue. Theexemplary catheter202 is shown inFIG. 2 with an open end with an open distal face to produce spray in a distal direction at thedistal tip204 and withradial apertures206 to produce spray in a radial direction. Alternative exemplary catheters may have only a distal tip and open distal face without having any radial apertures, or may have only radial apertures without having a distal tip with an open distal face.
• With the system ofFIG. 1 and/or catheter ofFIG. 2, for example, freezing of fluids on the target tissue and/or freezing of the target tissue is apparent to the medical professional by the acquisition of a white color by the target tissue. The white color, resulting from surface frost, indicates the onset of mucosal or other tissue freezing sufficient to initiate destruction of the diseased or abnormal tissue. The operator may use a system timer to freeze for a specified duration once initial freeze is achieved in order to control the depth of injury. The delivery of cyrogen may be metered and controlled via a feedback loop that monitors readings from one or more temperature sensors on the catheter shaft. The medical professional may observe the degree of freezing and stop the spray as soon as the surface achieves the desired whiteness of color. The operator may monitor the target tissue to determine when freeze has occurred via the camera integrated into the endoscope. The operator may manipulate the catheter to freeze the target tissue. Once the operation is complete, the catheter, endoscope, and any other instruments, such as a cryodecompression tube for the evacuation by passive or active venting of fluids from the patient (e.g., cryospray gases), are withdrawn from the patient.
• The delivery of a multiphase flow of cryogen through thecatheter202 leads to theradial apertures206 and/ordistal tip204 for cryo spray to exit the catheter. Cryogens may partially boil as they travel down thecatheter202 and the resulting mixture may be released out of the exit points at thedistal end212 of thecatheter202. Theradial apertures206 in thedistal end212 of thecatheter202 are meant to emit cryospray onto the inner wall of tissue in a body lumen.
• When cryospray exits thedistal end212 of thecatheter202 through theradial holes206, it does so typically in an orthogonal direction or angle from the catheter202 (i.e., along an axis transverse to the longitudinal axis of the catheter). Increasing the ratio of the width of radial holes to the diameter of these apertures may improve spray orthogonality, which may increase cooling efficiency.
• As noted above, distributing flow of cryogen mixtures (e.g., liquid and gas, such as liquid nitrogen and its vapor) through a catheter central lumen to multiple apertures may be difficult due to the higher momentum of the liquid cryogen when compared to the gaseous cryogen in the cryogen mixture. The gaseous portions of the cryogen mixture may easily flow out of the more proximal apertures (e.g., radial apertures), while the liquid portion of the cryogen may continue to flow axially to the distal end of the catheter, resulting in a flow imbalance. This flow imbalance among rows of apertures may limit the uniformity and effective length of a cryogen spray volume and coverage area. The momentum of fluid flow within a catheter and/or catheter tip may also be difficult to direct efficiently among a plurality of apertures arranged at different points longitudinally and radially.
• Distal momentum of fluid traveling within a catheter may still exist when sprayed out of the apertures. This distal momentum may progress fluids distally past the spray site, which may be undesirable and may result in patient harms such as distention or perforation of organs.
• Various embodiments of devices with different configurations of flow distribution elements may improve the uniformity of flow distribution across one or more radial apertures and increase the efficiency and efficacy of radial spray. Some of the embodiments may have a body with a longitudinal axis, a proximal end, a distal end, a mid-portion extending therebetween, and an exterior radial surface. A central lumen may extend within the body along the longitudinal axis from the proximal end of the body into at least the mid-portion of the body. One or more apertures may be distributed about the exterior radial surface of the body. The apertures may be radial openings, or slot openings, or both. The central lumen may include a lumen of a catheter, or include a portion of a lumen of a catheter, or include a proximal section of a body that does not include the lumen of a catheter. The central lumen may extend through the distal end of the body, e.g., to allow passage of instruments through the central lumen. The central lumen may transition from a smaller diameter to a larger diameter between the proximal end of the body and the mid-portion of the body. This transition may be at an angle, e.g., of about 25 to about 30 degrees from a longitudinal axis of the body in the direction of the large diameter. A flow distribution element may be in fluid communication with the central lumen and the one or more apertures. The flow distribution element may extend from the central lumen to a plurality of apertures about the body. The flow distribution element may help the flow of cryogen fluids from the central lumen to transition through the flow distribution element and out of the apertures more efficiently and with less flow imbalance. The various embodiments of devices with a flow distribution element may be mated with an end of a catheter, e.g., inserted into, bonded with, removably coupled to, or integrated into the end of a catheter as a continuous extension or unibody of the catheter. Various embodiments may include apertures that vary in diameter and/or in depth along the length of the body of the device. Lumens leading to apertures may vary in diameter and shape. Such variances may increase or decrease flow to particular apertures such that a net uniform or other desired application of spray for all of the apertures results.
• With reference toFIGS. 3A-3C, an embodiment of a device with aflow distribution element310 includeslumens314 fluidly connecting acentral lumen308 to a plurality ofapertures312 about abody300. Theflow distribution element310 includes a diffuser element, e.g.,cone316, at a proximal end of theflow distribution element310 with an apex of thecone316 that is axial with thecentral lumen308. The apex of thecone316 is directed toward the central lumen308 (i.e., in a proximal direction). A flow of cryogen through thecentral lumen308 from theproximal end302 is expanded conically to a larger diameter, because of thecone316, to enhance uniform distribution to a proximal end of thelumens314. The angle of the cone316 (as well as the angle of the wall of the body as the central lumen expands to a mid-portion of the body) may be an angle characteristic of a saturated multiphase mixture expansion, e.g., about 25° to about 30° for liquid nitrogen from a longitudinal axis of the body. The flow distribution element is then separated bymultiple lumens314. Eachlumen314 corresponds to a separate aperture312 (e.g., a row of radial apertures, a radial slot, or a ring). Eachlumen314 extends distally within thebody300 parallel to the longitudinal axis and then transitions to anaperture312 along aradial wall318 of thebody300 that is perpendicular to the longitudinal axis to acorresponding aperture312. The plurality oflumens314 may include discrete components that are configured to be nested together to form thebody300. When the flow from alumen314 reaches theradial wall318, the flow momentum changes from a substantially distal, axial direction to a substantially radial direction, towards theaperture312. While thebody300 may be substantially cylindrical as inFIGS. 3A and 3B, thebody300 may take on other shapes, such as an ellipsoid as inFIG. 3C. An ellipsoid or other shape of body may be configured with different paths for the lumens to the apertures, e.g., other than perpendicular to the longitudinal axis of thebody300, in order to direct spray in a multitude of directions, such as a direction normal to a curved outer surface of thebody300, such as an angle from an axis that is perpendicular to the longitudinal axis of the body where the angle may be 5°, 10°, 15°, or the like (e.g.,FIG. 3C). For example, thebody300 depicted inFIG. 3C may be ellipsoid-shaped with the major axis of the ellipsoid shape coinciding with the longitudinal axis of thebody300. Eachlumen314 may extend distally within thebody300 parallel to the longitudinal axis and then transition along a radial wall of thebody300 that is perpendicular to the exterior radial surface of thebody300 to acorresponding aperture312. Exterior radial surfaces may correspond to an anatomy that is to be treated. For example, the spray from each aperture may be oriented normal to the surface of the target tissue. Anatomies such as a hiatal hernia may be treated with such an elliptical exterior radial surface of a body. Aflow distribution element310 may include different configurations of a diffuser element that are coaxial with thecentral lumen308 and face proximally along the longitudinal axis toward theproximal end302 of thebody300 to distribute flow, such as thecone316 described above, or a device may not include thecone316 or other diffuser element such that flow may pass through acentral lumen308 in a distal direction out of thebody300.
• With reference toFIGS. 4A-4D, an embodiment of a device with aflow distribution element410 includeslumens414 extending from thecentral lumen408 to a plurality ofapertures412 about thebody400. A flow of cryogen through thecentral lumen408 expands substantially conically to a larger diameter because of the transition from the smaller diameter of thecentral lumen408 compared to the larger diameter of the mid-portion of the portion corresponding tooutermost lumen410. The angle of the transition may be an angle characteristic of a saturated multiphase mixture expansion, e.g., about 25° to about 30° for liquid nitrogen. The flow is then distributed through themultiple lumens410. Eachlumen410 corresponds to a separate row of apertures412 (e.g., radial apertures or radial slots or rings). As shown inFIG. 4B, thelumens410 extend distally within thebody400 parallel to the longitudinal axis and then transition gradually along a curve to correspondingapertures412, but the path may be as desired including as described above with respect toFIGS. 3A-3C. With a gradual curve, flow within anannular channel410 may transition from an axial direction to a radial direction along the length of thelumen410 with a longer radius of curvature and greater angle, than a 90-degree angle turn. Referring toFIG. 4C, an embodiment of aporous sheath416 is depicted. The sheath may be disposed about the exterior surface of thebody400 and cover theapertures412. Theporous sheath416 may comprise one or more porous rings and each ring may correspond to or cover a row ofapertures412. A porous sheath, such assheath416, may be placed over any embodiment of the present disclosure in order to help disperse the cryogen flow from an aperture into a uniform plume. A sheath may be fabricated in a multitude of ways such as into a woven mesh or with sintered particles having pore sizes chosen to optimally disperse the spray plume. The sheath may diffuse the spray from theapertures412 to create a more continuous spray pattern when compared to an array ofapertures412 without a sheath. Particles of the spray emitted from theapertures412 may be sintered by thesheath416, resulting in a substantially randomized and substantially uniform mist of spray. While thebody400 may be substantially cylindrical as inFIGS. 4A-4C, thebody400 may take on other shapes, such as abody400 with a scalloped exterior radial surface between theapertures412, as inFIG. 4D. The scalloped shape decreases the amount of material necessary to manufacture the embodiment. Theapertures412 ofFIGS. 4A and 4B may instead comprise of rings such as that illustrated in4C, but without thesheath416.
• With reference toFIGS. 5A and 5B, an embodiment of a device with aflow distribution element510 includesindependent lumens511 comprising elongate tubes extending from the central lumen508 to a plurality ofapertures512 about thebody500. Eachtubular lumen511 is associated with anindependent aperture512. Eachtubular lumen511 has a proximal portion that extends distally within thebody500 parallel with the central lumen508 and along a curve to a radial portion of thetubular lumen511 that is aligned with the associatedaperture512. A flow of cryogen through the central lumen of a catheter may be expanded to a larger diameter of theflow distribution element510. The flow is then distributed through thetubular lumens511. Thetubular lumens511 gradually extend to a radial portion that is radial with theapertures512. Various angles of curvature, including an angle normal to the longitudinal axis, as above, may be chosen as desired for particular applications. Eachtubular lumen511 inFIG. 5A transitions to anaperture512 gradually in an arc along the length of eachtubular lumen511. Flow within thetubular lumens511 smoothly transitions from an axial direction to a radial direction throughout the length of thetubular lumen511. Thetubular lumens511 are aligned in concentric radial circles at the proximal portion of thetubular lumens511.Tubular lumens511 that are closer514 to the longitudinal axis of thebody500 extend farther in a distal direction at the radial portion than thetubular lumens511 that are radially farther516 from the longitudinal axis of thebody500.
• With reference toFIG. 6, an embodiment of a device with a flow distribution element includes aporous body610 within a mid-portion of thebody600. Theporous body610 gradually becomes less permeable from aproximal end602 to a distal end604 along a longitudinal axis of the body. Theporous body610 also gradually becomes more permeable in a direction from thelongitudinal axis606 toward the exterior radial surface of the body600 (i.e., towards the apertures612). Theporous body610 may be anisotropic in other directions along theporous body610 to accommodate desirable flow and distribution properties. Aporous body610 with higher radial permeability relative to the axial permeability creates a flow pathway that will travel in a primarily radial path toward theapertures612. A porous body, such as thebody610, may be fabricated in a multitude of configurations such as multiple stacks of woven wire screens with increasing or decreasing density. Stacked screens inherently have anisotropic flow resistances due to the geometric difference between a flow path through the screen in a normal direction and a flow path longitudinally through the screen. Theporous body610 may be designed such that flow impedance increases distally with each axial row ofapertures612 such that flow is evenly distributed among the rows (e.g., by radially uniform change in permeability).
• With reference toFIGS. 7A and 7B, an embodiment of a device with a flow distribution element includes adistribution lumen710 that extends from thecentral lumen708 to the distal end of thebody700 and is in fluid communication with and substantially coaxial with thecentral lumen708. A plurality ofapertures712 about thebody700 are also in fluid communication with thecentral lumen708. Thedistribution lumen710 has sections in the direction of the distal end along the longitudinal axis of thebody700 that change in inner diameter and each include at least one of theapertures712. Each row ofapertures712, as radial holes, diminish in diameter in a distal direction along thebody700. Because cryogen flow may be typically distributed unevenly along the length of a body (i.e., more flow exits from theapertures712 in the distal portion of a device when compared toapertures712 in the proximal portion),larger diameter apertures712 in the proximal portion of the device allows for a less-resistive exit pathway for the flow than that of thesmaller diameter apertures712 at the distal portion. A flow of cryogen through thecentral lumen708 of this embodiment is constricted from the larger diameter of thecentral lumen708 to the smaller diameter of thedistribution lumen710. Thedistribution lumen710 extends in a distal direction and changes in diameter after each row ofapertures712 in the distal direction. InFIG. 7A, the change in diameter of thedistribution lumen710 is larger in the direction of the distal end. InFIG. 7B, the change in diameter of thedistribution lumen710 is smaller in the direction of the distal end. Some embodiments, e.g.,FIG. 7A, may have a section in the proximal portion of the distribution lumen (e.g.,710) that has a smaller diameter than the central lumen (e.g.,708). Some embodiments may have a combination of changing diameters of sections of a distribution lumen along thebody700. Thedistribution lumen710 may change in diameter in abrupt steps, or by gradual transitioning or tapering. A wall thickness about thedistribution lumen710 inFIG. 7A is reduced in a distal direction along thebody700, which relates to the depth of theapertures712. Thedeeper apertures712 in the proximal portion have a higher residence time for the flow as it exits theapertures712 than that of the shallower apertures in the distal portion of thebody700. As such, similar flow distribution may be achieved if the change in the inner diameter of the distribution lumen is inversely proportional to a change in wall thickness of the body from section to section along the distribution lumen, such as depicted inFIGS. 7A-7B. In such cases, the diameter of the exterior radial surface of the body along the distribution lumen may be kept constant. The varying diameter of thedistribution lumens710 affects the amount of fluid delivered from a flow of fluid to eachaperture712.
• With reference toFIGS. 8A and 8B, an embodiment of a device with a flow distribution element includes adistribution lumen810 that extends from a central lumen to the distal end of thebody800 and is in fluid communication with the central lumen. Thedistribution lumen810 includes a plurality of theapertures812 along the longitudinal axis. Aspring814 within thedistribution lumen810 has a distal end attached to the distal end of thebody800 and a proximal end. Anoscillator body816 is attached to the proximal end of thespring814, whereby theoscillator body816 oscillates in thedistribution lumen810 with flow pushing against a restoring force of thespring814 to more evenly distribute the flow to theapertures812. Theoscillator body816 has a conical diffuser element pointing against a direction of the flow from the proximal end of thebody800. A flow of cryogen through thedistribution lumen810 of this embodiment impacts theoscillator body816 and is expanded substantially conically to a larger diameter, because of the shape of the proximal side of theoscillator body816. The diffuser element of theoscillator816 body may take on other shapes such as an inverted cone, a dome, an inverted dome, a flat surface, any shape with an increasing diameter, a shape with an exponentially increasing diameter, and the like. The flow is directed to theapertures812 that are closest to theoscillator body816. The flow of fluid approaches theoscillator body816 in an axial direction and with axial force. This axial force translates theoscillator body816 in a distal direction, compressing thespring814. As theoscillator body816 translates further distally within thedistribution lumen810, it will pass by other rows ofapertures812 that theoscillator body816 will direct the cryogen flow to. The pulsatile nature of the flow of fluid will vary the force applied to theoscillator body816 and thespring814, causing theoscillator body816 to oscillate distally and proximally, distributing the flow among theapertures812 as theapertures812 are uncovered. A spring and damper are designed for the flow distribution element such that a stroke that translates theoscillator body816 axially will spend an equal amount of time passing each row ofapertures812. The time-averaged flow through each row ofapertures812 is equal, causing a uniform application of spray while reducing the instantaneous flow rate of fluid within the device and decreasing gas egression requirements. This embodiment does not supply all rows ofapertures812 evenly at the same time, and so the most-distal apertures812 do not receive an imbalanced amount of flow compared toother apertures812. Thespring814 may be attached within thedistribution lumen810 at a distal end or a proximal end. Thespring814 has a distal component associated with the distal end of thebody800 and a proximal component associated with theoscillator body816. Thespring814 may be a pair of magnets with one magnet of the pair as the distal component of thespring814 and the other magnet of the pair as the proximal component and theoscillatory body816. Like poles of the magnets may face one another that act as the restoring force of thespring814. Thespring814 may have the distal component attached to the distal end of thebody800, the proximal component attached to theoscillator body816, and a volume of gas compressed distally behind theoscillator body816 may act as the restoring force of thespring814. Theoscillatory body816 may be disposed onto hydrodynamic bearings that may reduce friction.
• With reference toFIGS. 9A-9C, an embodiment of a device with a flow distribution element includes adistribution lumen910 within thebody900 extending from a central lumen. Arod914 is rotatably disposed within thedistribution lumen910 and extends along a longitudinal axis of thebody900. Aturbine918 is axially disposed about therod914. A flow of fluid into thedistribution lumen910 will rotate theturbine918 and therod914. At least onemultilumen member916 is disposed about therod914 and distal to theturbine918. The flow of fluid is divided into radial segments that make up thelumens920 of the first multilumenmember931. At least onelumen920 of each of themultilumen members916 has an exposed radial portion that longitudinally coincides with one of the plurality of rows ofradial apertures912. Eachlumen920 of the multilumen member(s)931 terminates in a substantiallyradial wall922 adjacent to one of the rows ofapertures912 in a distal direction. The substantiallyradial wall922 terminates thelumen920 of the multilumenmember916 that has the exposed radial portion associated with a specific row ofapertures912. A portion of the flow of fluid that enters thelumen920 with an exposed radial portion will collide with the substantiallyradial wall922. The flow will be diverted from a substantially axial direction to a substantially radial direction out of theapertures912 that are in fluid communication with thelumen920 with an exposed radial portion. The remainder of the flow of fluid will travel distally through the remaininglumens920 of the first multilumenmember931. Theselumens920 are open at a distal end of the first multilumenmember931 for the flow of fluid to reach subsequentmultilumen members916 in the distal direction. Flow from thelumens920 that do not terminate in the substantiallyradial wall922 of the first multilumenmember931 will reach the second multilumenmember932. Flow from onemultilumen member916 distally to the next will subsequently lose flow from one of thelumens920 as flow continues from the first multilumenmember931, to the second multilumenmember932, to the third multilumenmember933, to the fourth multilumenmember934, and to the fifth multilumenmember935. Each multilumenmember916 has one substantiallyradial wall922 that is rotationally offset about therod914 from the substantiallyradial wall922 of othermultilumen members916. In this way, each of the radially exposedlumens920 of themultilumen members916 together form a spray pattern of about 360° about therod914 and through theapertures912. This 360° spray pattern coverage is distributed through each multilumen such that each multilumen sprays in an angular arc of about360/nwhere “n” is the number of multilumen members916 (e.g., each multilumen member inFIG. 9A sprays in an angular arc of about 72°). Themultilumen members916 are attached to therod914 such that theturbine918,rod914, and multilumenmembers916 rotate together within thedistribution lumen910. For example,FIG. 9B illustrates the angular position of therotatable turbine918,rod914, and multilumenmembers916 at time to.FIG. 9C illustrates the angular position of therotatable turbine918,rod914, and multilumenmembers916 at another instant of time t₁. At both t₀and t₁, there is an angular spray coverage of about 360°, however, the axial depth of the spray coverage varies at each substantiallyradial wall922 of each of themultilumen members931,932,933,934, and935. The axial distance between the rows ofapertures912 and the length of themultilumen members916 determine the amount of area covered by the fluid spray. This embodiment may create a large spray area without increasing the total flowrate necessary since only some of theapertures912 are active at any given instant.
• Referring toFIGS. 8A through 9C, embodiments of a device for enhanced spray according to the present disclosure may increase body lumen coverage of cryospray, without increasing the flowrate of fluid. These embodiments and the other embodiments of flow distribution elements described above, may allow for more efficient and accurate control of the rate and volume of fluid necessary to provide for treatment of the body lumen, while avoiding excess gas build up that may result in distension or other harmful effects. Exposing only a portion of the apertures to the fluid within the flow distribution element at a time, may allow for a lower flow rate of fluid when compared to an embodiment exposing all of the apertures to the flow of fluid throughout a treatment procedure. Even though only a portion of the apertures are exposed at one time, complete coverage of cryospray along all of the apertures may be maintained. A lower flow rate may result in less distal progression of the cryospray, which may be useful in certain anatomies and/or if maintaining a uniform gas egression rate is difficult.
• With reference toFIGS. 10A-10D, an embodiment of a device with a flow distribution element includes anelongate member1010 having a longitudinal axis, an open proximal end, a distal end, and a plurality oflumens1014 extending therebetween in fluid communication with a flow distribution element. The plurality oflumens1014 divides the flow of fluid into radial lumens (i.e., rather than one central lumen or multiple lumens). Lumens may have a flow imbalance if the flow is more centralized at the lumens that are most-axial or if the flow is more radial along the outer-most walls of theflow distribution element1006. Aflow distribution element1006 disposed about theelongate member1010 includes a plurality of longitudinally adjacentannular chambers1020, eachchamber1020 having a proximal end, a distal end, and acentral lumen1018 extending therethrough that receives theelongate member1010. Eachchamber1020 has one or moreradial apertures1012 about an outer surface of thechamber1020. Each lumen of the plurality oflumens1014 has at least onesupply aperture1016 in fluid communication with a dedicated chamber for that lumen. A fluid supplied through adevice1000 of this embodiment flows through the elongate member via the three, radially partitioned lumens of the plurality oflumens1014. The flow within each lumen will exit the lumen through thesupply aperture1016 of the lumen into thededicated chamber1006. The flow will then exit thechamber1006 through theradial apertures1012 and out of thedevice1000. Dividing the flow within the plurality oflumens1014 to separatechambers1006 each having their ownradial apertures1012 helps to produce a balanced flow to theradial apertures1012 and spray from theradial apertures1012. Each of the plurality oflumens1014 of the elongate member is dedicated to arespective chamber1006 and has at least onededicated supply aperture1016 in fluid communication therewith. Theelongate body1000 may be mated with a catheter. Each lumen of the plurality oflumens1014 of theelongate member1010 may terminate at asupply aperture1016 associated with its respectiveannular chamber1020.
• With reference toFIG. 11, an embodiment of a device with aflow distribution element1110 has theflow distribution element1110 extending partially along anelongate body1100. Thebody1100 is configured to be inserted into or be integral with a distal end opening of acatheter1130. Thebody1100 has a longitudinal axis, a proximal end, a distal end, and abackstop1106 at the distal end. Theflow distribution element1110 includes a plurality offins1116 extending radially from a longitudinal axis of theelongate body1100 that are configured to engage an inner surface of thecatheter1130. Thebackstop1106 has asurface1108 perpendicular to and facing the distal end opening of thecatheter1130 when theelongate body1100 is inserted into thecatheter1130. Thesurface1108 is longitudinally offset from a distal end opening of thecatheter1130 in a distal direction forming aradial aperture1112 around the opening. A 360°aperture1112 is created by the space between thesurface1108 and the distal end of thecatheter1130. A flow of fluid through thecatheter1130 is directed from a substantially axial direction to a substantially radial direction through theaperture1112 upon colliding with thesurface1108.
• With reference toFIGS. 12A and 12B, an embodiment of a device with aflow distribution element1210 has the flow distribution element extending partially along anelongate body1200 and thebody1200 is configured to be inserted into or integral with acatheter1230. Theelongate body1200 has a proximal end, a distal end, and abackstop1206 at the distal end. Theflow distribution element1210 includesfins1216. Thefins1216 gradually extend radially further from a longitudinal axis of theelongate body1200 as thefins1216 extend along theelongate body1200 in the direction of the backstop. Thefins1216 extend along theelongate body1200 in a helical pattern and in a distal direction. Thebackstop1206 is configured to engage the inner surface of thecatheter1230. Theelongate body1200 may engage acatheter1230 with apertures1212, which may be radial apertures that receive protrusions on the wall of thecatheter1230. Conversely, the protrusions may be on the device and configured be received within notches on the wall of acatheter1230. A flow of fluid through thecatheter1230 is directed from a substantially axial direction to a substantially radial direction through the apertures1212 by thefins1216 as well as theelongate body1200 transitioning into thebackstop1206. Theelongate body1200 has aslope1214 that transitions from thebody1200 to thebackstop1206 such that cross-sectional resistance to the flow of fluid increases as the flow translates distally. The helical pattern of thefins1216 encourages the flow to rotate, increasing radial flow towards the apertures1212 due to centripetal acceleration. Theslope1214 portion andfins1210 of theelongate body1200 may be independent of thebackstop1206 and instead be disposed on an axial shaft and motor assembly. The motor may rotate theslope1214 portion andfins1210, directing the flow of fluid generally toward the apertures1212.
• With reference toFIG. 13, an embodiment of a device with a flow distribution element has anelongate body1300 configured to be inserted into acatheter1330. Theelongate body1300 engages thecatheter1330 via one ormore ridges1302 along theelongate body1300. Aring1332 may fit into a notch of thecatheter1330 such that thebody1300 is held in place. Instead of or in addition to thering1332 and/orridges1302, thebody1300 may be fixed into place within thecatheter1330 via threading, bonding, interference, and the like. Theelongate body1300 has a proximal end, a distal end, and abackstop1306 attached at the distal end. Thebackstop1306 has aconcave surface1308 facing the distal end opening of thecatheter1330. Theflow distribution element1310 includes adiffuser element1314 from theconcave surface1308 that extends proximally towards a lumen of thecatheter1330 and against a direction of flow from the opening of thecatheter1330. Thediffuser element1314 has a curved transition from the tip to theconcave surface1308. Thebackstop1306 and theflow distribution element1310 are configured to be concentrically disposed within or integrated as part of a lumen of theelongate body1300. Theconcave surface1308 is offset from the distal end of theelongate body1300, creating anaperture1312. Theaperture1312 is oriented 20° proximally from a perpendicular plane to the longitudinal axis of theelongate body1300. This proximal orientation directs flow from theaperture1312 proximally such that the fluid from the flow does not spray distally into the body lumen. Other angles of orientation may be selected as desired to achieve a desired deflection pattern. Thebackstop1306 may be connected to theelongate body1300 by several struts of thediffuser element1314 that engage theelongate body1300. The struts of thediffuser element1314 distally span the gap of theaperture1312, but are thin enough to not substantially obstruct theaperture1312. The thickness and number of struts in thediffuser element1314 may be determined by the desired amount of connection strength between thebackstop1306 and theelongate body1300 and the desired flow of spray from theaperture1312.
• In various embodiments, the apertures may include multiple rows of apertures, such as, e.g., 6 rows spaced about 5 millimeters apart. The apertures may comprise a variety of shapes and sizes, such as, e.g., 24 equally spaced holes of about 0.015″ (about 0.381 millimeters) diameter. The apertures may be oriented radially, proximally, or distally, or some combination thereof.
• All of the devices and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the devices and methods of this disclosure have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations can be applied to the devices and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the spirit and scope of the disclosure. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit and scope of the disclosure as defined by the appended claims.

Claims (20)

What is claimed is:

1. A device for a radial spray catheter, comprising:

a body having a longitudinal axis, a proximal end, a distal end, a mid-portion extending therebetween, and an exterior radial surface;

a central lumen extending within the body along the longitudinal axis from the proximal end of the body into at least the mid-portion of the body;

one or more apertures distributed about the exterior radial surface of the body; and

a flow distribution element in fluid communication with the central lumen and the one or more apertures.

2. The device ofclaim 1, wherein the central lumen extends through the distal end of the body.

3. The device ofclaim 1, wherein the central lumen transitions from a smaller diameter to a larger diameter between the proximal end of the body and the mid-portion of the body.

4. The device ofclaim 1, wherein the proximal end of the body is configured to be mated with a distal end of the catheter.

5. The device ofclaim 1, wherein the flow distribution element comprises a diffuser element that is coaxial with the central lumen and faces proximally along the longitudinal axis of the body.

6. The device ofclaim 5, wherein the diffuser element is a cone with a cone apex that faces proximally along the longitudinal axis of the body.

7. The device ofclaim 1, wherein the flow distribution element comprises a plurality of lumens fluidly connecting the central lumen with a plurality of the one or more apertures, and wherein each lumen extends distally within the body parallel to the longitudinal axis and then transitions along a radial wall of the body that is perpendicular to the longitudinal axis to a corresponding aperture.

8. The device ofclaim 7, wherein the lumens extend distally within the body parallel to the longitudinal axis and then transition gradually along a curve to corresponding apertures.

9. The device ofclaim 1, further comprising a porous sheath or porous rings about the exterior radial surface of the body covering the apertures.

10. The device ofclaim 1, wherein the flow distribution element comprises a plurality of independent lumens comprising elongate tubes, each tubular lumen associated with an independent aperture.

11. The device ofclaim 10, wherein the tubular lumens are aligned in concentric radial circles at the proximal portion, and wherein the lumens radially closer to the longitudinal axis of the body extend farther distally at the radial portion than the lumens radially farther from the longitudinal axis of the body.

12. The device ofclaim 1, wherein the flow distribution element comprises a distribution lumen that extends from the central lumen to the distal end of the body and is in fluid communication and substantially coaxial with the central lumen, and wherein the distribution lumen has sections in the direction of the distal end along the longitudinal axis of the body that change in inner diameter and each include at least one of the apertures.

13. The device ofclaim 1, wherein the flow distribution element comprises a distribution lumen that extends from the central lumen to the distal end of the body and is in fluid communication with the central lumen, and wherein the distribution lumen includes a plurality of the apertures along the longitudinal axis, a spring within the distribution lumen having a distal component associated with the distal end of the body and a proximal component associated with an oscillator body, whereby the oscillator body oscillates in the distribution lumen with flow pushing against a restoring force of the spring to distribute the flow to the apertures.

14. The device ofclaim 1, wherein the flow distribution element comprises:

a distribution lumen within the body extending from the central lumen;

a rod rotatably disposed within the distribution lumen along the longitudinal axis of the body;

a turbine axially disposed about the rod; and

a multilumen member disposed about the rod, distal to the turbine and extending along the rod, wherein each lumen of the multilumen member has an exposed radial portion that longitudinally coincides with a respective one of a plurality of radial rows of the apertures, and wherein each lumen of the multilumen member terminates at a substantially radial wall that is adjacent distally to the respective one of the radial rows of apertures for each lumen.

15. A device for a radial spray catheter, comprising an elongate member having a longitudinal axis, an open proximal end, a distal end, and plurality of lumens extending therebetween in fluid communication with a flow distribution element.

16. The device ofclaim 15, wherein the flow distribution element is disposed about the elongate member and comprises a plurality of longitudinally adjacent annular chambers, each chamber having a proximal end, a distal end, a central lumen extending therethrough that receives the elongate member, and a plurality of radial apertures about an outer surface of the chamber.

17. The device ofclaim 15, wherein each one of the plurality of lumens of the elongate member is dedicated to a respective each one of the plurality of chambers and has at least one dedicated supply aperture in fluid communication therewith.

18. A device for a radial spray catheter, comprising:

an elongate body configured to be inserted into a distal end opening of a catheter, the body having a longitudinal axis, a proximal end, and a distal end; and

a flow distribution element extending at least partially between the proximal and distal end of the body, and including a backstop at the distal end of the body.

19. The device ofclaim 18, wherein the flow distribution element further comprises a plurality of fins extending radially from the longitudinal axis of the elongate body, the fins configured to engage an inner surface of the catheter.

20. The device ofclaim 18, wherein the backstop has a surface perpendicular to and facing the distal end opening of the catheter when the elongate body is inserted into the catheter, and wherein the surface is longitudinally offset from the distal end opening of the catheter in a distal direction forming a radial aperture around the opening.

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