Patent Description:
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.

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. For example, document <CIT> discloses systems and methods for variable injection flow. Document <CIT> discloses a catheter with uniform spray pattern along infusion length.

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 -<NUM>) 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 -<NUM> but still very low (e.g., -<NUM> 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 <NUM> to -<NUM>, 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.

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 <NUM> 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.

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 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 <CIT> and <CIT>, and <CIT> and <CIT>, 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 United States Provisional Patent Application having Attorney Docket number <NUM>, filed concurrently herewith.

In one embodiment of a cyrospray delivery system configured for devices to enhance cryospray from a catheter, as illustrated in <FIG>, a catheter <NUM> is connected to a cryotherapy console <NUM> at a catheter interface <NUM>. The catheter <NUM> 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 the monitor <NUM>, 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 the catheter <NUM> via a foot petal <NUM>. The catheter <NUM> may have an insulated portion <NUM> and a distal end <NUM>.

As an example of the fluid mechanics of cryospray formation and supply, with reference to the system illustrated in <FIG>, as cryogen (e.g., liquid nitrogen) travels from the tank to the proximal end of cryogen delivery catheter <NUM>, the liquid warms and starts to boil, resulting in cool gas emerging from the distal end <NUM> of catheter <NUM>. The amount of boiling in the catheter <NUM> depends on the mass, surface area, and thermal capacity of catheter <NUM>. When the liquid nitrogen undergoes phase change from liquid to gaseous nitrogen, additional pressure is created throughout the length of catheter <NUM>. This is especially true at a solenoid/catheter junction, where the diameter of the supply tube to the lumen of catheter <NUM> decreases, e.g., from approximately <NUM> to approximately <NUM>,<NUM> (<NUM> inches to approximately <NUM> inches), respectively. The lumen of the catheter <NUM> may have a diameter, e.g., ranging between <NUM> and <NUM> (<NUM> and <NUM> 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 the catheter <NUM> 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 to <FIG>, as an example, the catheter <NUM> is connected to a console <NUM>. The console <NUM> contains the tank that supplies the cryogen. The console <NUM> may include precooling and defrost features. The console <NUM> and/or catheter <NUM> include valving and plumbing to deliver the cryogen under pressure, e.g., delivering low pressure to the distal tip <NUM> of the catheter <NUM>. There may be sensors within the console <NUM> and/or the catheter <NUM> to measure the temperature of the cryogen and/or the tissue. There may be a feedback loop for metered control of cryogen dosing. A pedal <NUM> may be used to control the cryogen delivery, or the cryogen delivery may be timed for a predetermined dosage. The distal tip <NUM> may be openended and/or include radial apertures. The console <NUM> may include software and/or hardware with safety features. The console <NUM> may include an interactive user interface. The console <NUM> may include control settings for a cryospray therapy procedure. The console <NUM> may include cryospray procedure profiles for pre-determined delivering of cryospray.

With reference to <FIG>, an exemplary cyrospray catheter in accordance with an embodiment of the present disclosure is illustrated. The catheter <NUM> is placed within a patient such that the distal end <NUM> is in proximity to the target tissue. A medical professional may visualize placement of the distal end <NUM> of the catheter <NUM> via a camera in an endoscope and/or through fluoroscopy. The marking bands <NUM> may be visualized using the camera and/or may be radiopaque for visualization with a fluoroscope. With the distal end <NUM> in position, the medical professional may introduce cryogen into the catheter <NUM>. When the cryogen reaches the distal end <NUM> of catheter <NUM> it exits the distal tip <NUM> and/or the radial apertures <NUM> as a cyrospray towards the target tissue. The exemplary catheter <NUM> is shown in <FIG> with an open end with an open distal face to produce spray in a distal direction at the distal tip <NUM> and with radial apertures <NUM> 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 of <FIG> and/or catheter of <FIG>, 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 the catheter <NUM> leads to the radial apertures <NUM> and/or distal tip <NUM> for cryospray to exit the catheter. Cryogens may partially boil as they travel down the catheter <NUM> and the resulting mixture may be released out of the exit points at the distal end <NUM> of the catheter <NUM>. The radial apertures <NUM> in the distal end <NUM> of the catheter <NUM> are meant to emit cryospray onto the inner wall of tissue in a body lumen.

When cryospray exits the distal end <NUM> of the catheter <NUM> through the radial holes <NUM>, it does so typically in an orthogonal direction or angle from the catheter <NUM> (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 <NUM> to about <NUM> 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 to <FIG>, an embodiment of a device with a flow distribution element <NUM> includes lumens <NUM> fluidly connecting a central lumen <NUM> to a plurality of apertures <NUM> about a body <NUM>. The flow distribution element <NUM> includes a diffuser element, e.g., cone <NUM>, at a proximal end of the flow distribution element <NUM> with an apex of the cone <NUM> that is axial with the central lumen <NUM>. The apex of the cone <NUM> is directed toward the central lumen <NUM> (i.e., in a proximal direction). A flow of cryogen through the central lumen <NUM> from the proximal end <NUM> is expanded conically to a larger diameter, because of the cone <NUM>, to enhance uniform distribution to a proximal end of the lumens <NUM>. The angle of the cone <NUM> (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 <NUM>° to about <NUM>° for liquid nitrogen from a longitudinal axis of the body. The flow distribution element is then separated by multiple lumens <NUM>. Each lumen <NUM> corresponds to a separate aperture <NUM> (e.g., a row of radial apertures, a radial slot, or a ring). Each lumen <NUM> extends distally within the body <NUM> parallel to the longitudinal axis and then transitions to an aperture <NUM> along a radial wall <NUM> of the body <NUM> that is perpendicular to the longitudinal axis to a corresponding aperture <NUM>. The plurality of lumens <NUM> may include discrete components that are configured to be nested together to form the body <NUM>. When the flow from a lumen <NUM> reaches the radial wall <NUM>, the flow momentum changes from a substantially distal, axial direction to a substantially radial direction, towards the aperture <NUM>. While the body <NUM> may be substantially cylindrical as in <FIG>, the body <NUM> may take on other shapes, such as an ellipsoid as in <FIG>. 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 the body <NUM>, in order to direct spray in a multitude of directions, such as a direction normal to a curved outer surface of the body <NUM>, such as an angle from an axis that is perpendicular to the longitudinal axis of the body where the angle may be <NUM>°, <NUM>°, <NUM>°, or the like (e.g., <FIG>). For example, the body <NUM> depicted in <FIG> may be ellipsoid-shaped with the major axis of the ellipsoid shape coinciding with the longitudinal axis of the body <NUM>. Each lumen <NUM> may extend distally within the body <NUM> parallel to the longitudinal axis and then transition along a radial wall of the body <NUM> that is perpendicular to the exterior radial surface of the body <NUM> to a corresponding aperture <NUM>. 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. A flow distribution element <NUM> may include different configurations of a diffuser element that are coaxial with the central lumen <NUM> and face proximally along the longitudinal axis toward the proximal end <NUM> of the body <NUM> to distribute flow, such as the cone <NUM> described above, or a device may not include the cone <NUM> or other diffuser element such that flow may pass through a central lumen <NUM> in a distal direction out of the body <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element <NUM> includes lumens <NUM> extending from the central lumen <NUM> to a plurality of apertures <NUM> about the body <NUM>. A flow of cryogen through the central lumen <NUM> expands substantially conically to a larger diameter because of the transition from the smaller diameter of the central lumen <NUM> compared to the larger diameter of the mid-portion of the portion corresponding to outermost lumen <NUM>. The angle of the transition may be an angle characteristic of a saturated multiphase mixture expansion, e.g., about <NUM>° to about <NUM>° for liquid nitrogen. The flow is then distributed through the multiple lumens <NUM>. Each lumen <NUM> corresponds to a separate row of apertures <NUM> (e.g., radial apertures or radial slots or rings). As shown in <FIG>. the lumens <NUM> extend distally within the body <NUM> parallel to the longitudinal axis and then transition gradually along a curve to corresponding apertures <NUM>, but the path may be as desired including as described above with respect to <FIG>. With a gradual curve, flow within an annular channel <NUM> may transition from an axial direction to a radial direction along the length of the lumen <NUM> with a longer radius of curvature and greater angle, than a <NUM>-degree angle turn. Referring to <FIG>, an embodiment of a porous sheath <NUM> is depicted. The sheath may be disposed about the exterior surface of the body <NUM> and cover the apertures <NUM>. The porous sheath <NUM> may comprise one or more porous rings and each ring may correspond to or cover a row of apertures <NUM>. A porous sheath, such as sheath <NUM>, 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 the apertures <NUM> to create a more continuous spray pattern when compared to an array of apertures <NUM> without a sheath. Particles of the spray emitted from the apertures <NUM> may be sintered by the sheath <NUM>, resulting in a substantially randomized and substantially uniform mist of spray. While the body <NUM> may be substantially cylindrical as in <FIG>, the body <NUM> may take on other shapes, such as a body <NUM> with a scalloped exterior radial surface between the apertures <NUM>, as in <FIG>. The scalloped shape decreases the amount of material necessary to manufacture the embodiment. The apertures <NUM> of <FIG> may instead comprise of rings such as that illustrated in 4C, but without the sheath <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element <NUM> includes independent lumens <NUM> comprising elongate tubes extending from the central lumen <NUM> to a plurality of apertures <NUM> about the body <NUM>. Each tubular lumen <NUM> is associated with an independent aperture <NUM>. Each tubular lumen <NUM> has a proximal portion that extends distally within the body <NUM> parallel with the central lumen <NUM> and along a curve to a radial portion of the tubular lumen <NUM> that is aligned with the associated aperture <NUM>. A flow of cryogen through the central lumen of a catheter may be expanded to a larger diameter of the flow distribution element <NUM>. The flow is then distributed through the tubular lumens <NUM>. The tubular lumens <NUM> gradually extend to a radial portion that is radial with the apertures <NUM>. Various angles of curvature, including an angle normal to the longitudinal axis, as above, may be chosen as desired for particular applications. Each tubular lumen <NUM> in <FIG> transitions to an aperture <NUM> gradually in an arc along the length of each tubular lumen <NUM>. Flow within the tubular lumens <NUM> smoothly transitions from an axial direction to a radial direction throughout the length of the tubular lumen <NUM>. The tubular lumens <NUM> are aligned in concentric radial circles at the proximal portion of the tubular lumens <NUM>. Tubular lumens <NUM> that are closer <NUM> to the longitudinal axis of the body <NUM> extend farther in a distal direction at the radial portion than the tubular lumens <NUM> that are radially farther <NUM> from the longitudinal axis of the body <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element includes a porous body <NUM> within a mid-portion of the body <NUM>. The porous body <NUM> gradually becomes less permeable from a proximal end <NUM> to a distal end <NUM> along a longitudinal axis of the body. The porous body <NUM> also gradually becomes more permeable in a direction from the longitudinal axis <NUM> toward the exterior radial surface of the body <NUM> (i.e., towards the apertures <NUM>). The porous body <NUM> may be anisotropic in other directions along the porous body <NUM> to accommodate desirable flow and distribution properties. A porous body <NUM> with higher radial permeability relative to the axial permeability creates a flow pathway that will travel in a primarily radial path toward the apertures <NUM>. A porous body, such as the body <NUM>, 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. The porous body <NUM> may be designed such that flow impedance increases distally with each axial row of apertures <NUM> such that flow is evenly distributed among the rows (e.g., by radially uniform change in permeability).

With reference to <FIG>, an embodiment of a device with a flow distribution element includes a distribution lumen <NUM> that extends from the central lumen <NUM> to the distal end of the body <NUM> and is in fluid communication with and substantially coaxial with the central lumen <NUM>. A plurality of apertures <NUM> about the body <NUM> are also in fluid communication with the central lumen <NUM>. The distribution lumen <NUM> has sections in the direction of the distal end along the longitudinal axis of the body <NUM> that change in inner diameter and each include at least one of the apertures <NUM>. Each row of apertures <NUM>, as radial holes, diminish in diameter in a distal direction along the body <NUM>. Because cryogen flow may be typically distributed unevenly along the length of a body (i.e., more flow exits from the apertures <NUM> in the distal portion of a device when compared to apertures <NUM> in the proximal portion), larger diameter apertures <NUM> in the proximal portion of the device allows for a lessresistive exit pathway for the flow than that of the smaller diameter apertures <NUM> at the distal portion. A flow of cryogen through the central lumen <NUM> of this embodiment is constricted from the larger diameter of the central lumen <NUM> to the smaller diameter of the distribution lumen <NUM>. The distribution lumen <NUM> extends in a distal direction and changes in diameter after each row of apertures <NUM> in the distal direction. In <FIG>, the change in diameter of the distribution lumen <NUM> is larger in the direction of the distal end. In <FIG>, the change in diameter of the distribution lumen <NUM> is smaller in the direction of the distal end. Some embodiments, e.g., <FIG>, may have a section in the proximal portion of the distribution lumen (e.g., <NUM>) that has a smaller diameter than the central lumen (e.g., <NUM>). Some embodiments may have a combination of changing diameters of sections of a distribution lumen along the body <NUM>. The distribution lumen <NUM> may change in diameter in abrupt steps, or by gradual transitioning or tapering. A wall thickness about the distribution lumen <NUM> in <FIG> is reduced in a distal direction along the body <NUM>, which relates to the depth of the apertures <NUM>. The deeper apertures <NUM> in the proximal portion have a higher residence time for the flow as it exits the apertures <NUM> than that of the shallower apertures in the distal portion of the body <NUM>. 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 in <FIG>. 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 the distribution lumens <NUM> affects the amount of fluid delivered from a flow of fluid to each aperture <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element includes a distribution lumen <NUM> that extends from a central lumen to the distal end of the body <NUM> and is in fluid communication with the central lumen. The distribution lumen <NUM> includes a plurality of the apertures <NUM> along the longitudinal axis. A spring <NUM> within the distribution lumen <NUM> has a distal end attached to the distal end of the body <NUM> and a proximal end. An oscillator body <NUM> is attached to the proximal end of the spring <NUM>, whereby the oscillator body <NUM> oscillates in the distribution lumen <NUM> with flow pushing against a restoring force of the spring <NUM> to more evenly distribute the flow to the apertures <NUM>. The oscillator body <NUM> has a conical diffuser element pointing against a direction of the flow from the proximal end of the body <NUM>. A flow of cryogen through the distribution lumen <NUM> of this embodiment impacts the oscillator body <NUM> and is expanded substantially conically to a larger diameter, because of the shape of the proximal side of the oscillator body <NUM>. The diffuser element of the oscillator <NUM> 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 the apertures <NUM> that are closest to the oscillator body <NUM>. The flow of fluid approaches the oscillator body <NUM> in an axial direction and with axial force. This axial force translates the oscillator body <NUM> in a distal direction, compressing the spring <NUM>. As the oscillator body <NUM> translates further distally within the distribution lumen <NUM>, it will pass by other rows of apertures <NUM> that the oscillator body <NUM> will direct the cryogen flow to. The pulsatile nature of the flow of fluid will vary the force applied to the oscillator body <NUM> and the spring <NUM>, causing the oscillator body <NUM> to oscillate distally and proximally, distributing the flow among the apertures <NUM> as the apertures <NUM> are uncovered. A spring and damper are designed for the flow distribution element such that a stroke that translates the oscillator body <NUM> axially will spend an equal amount of time passing each row of apertures <NUM>. The time-averaged flow through each row of apertures <NUM> 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 of apertures <NUM> evenly at the same time, and so the most-distal apertures <NUM> do not receive an imbalanced amount of flow compared to other apertures <NUM>. The spring <NUM> may be attached within the distribution lumen <NUM> at a distal end or a proximal end. The spring <NUM> has a distal component associated with the distal end of the body <NUM> and a proximal component associated with the oscillator body <NUM>. The spring <NUM> may be a pair of magnets with one magnet of the pair as the distal component of the spring <NUM> and the other magnet of the pair as the proximal component and the oscillatory body <NUM>. Like poles of the magnets may face one another that act as the restoring force of the spring <NUM>. The spring <NUM> may have the distal component attached to the distal end of the body <NUM>, the proximal component attached to the oscillator body <NUM>, and a volume of gas compressed distally behind the oscillator body <NUM> may act as the restoring force of the spring <NUM>. The oscillatory body <NUM> may be disposed onto hydrodynamic bearings that may reduce friction.

With reference to <FIG>, an embodiment of a device with a flow distribution element includes a distribution lumen <NUM> within the body <NUM> extending from a central lumen. A rod <NUM> is rotatably disposed within the distribution lumen <NUM> and extends along a longitudinal axis of the body <NUM>. A turbine <NUM> is axially disposed about the rod <NUM>. A flow of fluid into the distribution lumen <NUM> will rotate the turbine <NUM> and the rod <NUM>. At least one multilumen member <NUM> is disposed about the rod <NUM> and distal to the turbine <NUM>. The flow of fluid is divided into radial segments that make up the lumens <NUM> of the first multilumen member <NUM>. At least one lumen <NUM> of each of the multilumen members <NUM> has an exposed radial portion that longitudinally coincides with one of the plurality of rows of radial apertures <NUM>. Each lumen <NUM> of the multilumen member(s) <NUM> terminates in a substantially radial wall <NUM> adjacent to one of the rows of apertures <NUM> in a distal direction. The substantially radial wall <NUM> terminates the lumen <NUM> of the multilumen member <NUM> that has the exposed radial portion associated with a specific row of apertures <NUM>. A portion of the flow of fluid that enters the lumen <NUM> with an exposed radial portion will collide with the substantially radial wall <NUM>. The flow will be diverted from a substantially axial direction to a substantially radial direction out of the apertures <NUM> that are in fluid communication with the lumen <NUM> with an exposed radial portion. The remainder of the flow of fluid will travel distally through the remaining lumens <NUM> of the first multilumen member <NUM>. These lumens <NUM> are open at a distal end of the first multilumen member <NUM> for the flow of fluid to reach subsequent multilumen members <NUM> in the distal direction. Flow from the lumens <NUM> that do not terminate in the substantially radial wall <NUM> of the first multilumen member <NUM> will reach the second multilumen member <NUM>. Flow from one multilumen member <NUM> distally to the next will subsequently lose flow from one of the lumens <NUM> as flow continues from the first multilumen member <NUM>, to the second multilumen member <NUM>, to the third multilumen member <NUM>, to the fourth multilumen member <NUM>, and to the fifth multilumen member <NUM>. Each multilumen member <NUM> has one substantially radial wall <NUM> that is rotationally offset about the rod <NUM> from the substantially radial wall <NUM> of other multilumen members <NUM>. In this way, each of the radially exposed lumens <NUM> of the multilumen members <NUM> together form a spray pattern of about <NUM>° about the rod <NUM> and through the apertures <NUM>. This <NUM>° spray pattern coverage is distributed through each multilumen such that each multilumen sprays in an angular arc of about <NUM>/n where "n" is the number of multilumen members <NUM> (e.g., each multilumen member in <FIG> sprays in an angular arc of about <NUM>°). The multilumen members <NUM> are attached to the rod <NUM> such that the turbine <NUM>, rod <NUM>, and multilumen members <NUM> rotate together within the distribution lumen <NUM>. For example, <FIG> illustrates the angular position of the rotatable turbine <NUM>, rod <NUM>, and multilumen members <NUM> at time t<NUM>. <FIG> illustrates the angular position of the rotatable turbine <NUM>, rod <NUM>, and multilumen members <NUM> at another instant of time t<NUM>. At both t<NUM> and t<NUM>, there is an angular spray coverage of about <NUM>°, however, the axial depth of the spray coverage varies at each substantially radial wall <NUM> of each of the multilumen members <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The axial distance between the rows of apertures <NUM> and the length of the multilumen members <NUM> 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 the apertures <NUM> are active at any given instant.

Referring to <FIG>, 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 to <FIG>, an embodiment of a device with a flow distribution element includes an elongate member <NUM> having a longitudinal axis, an open proximal end, a distal end, and a plurality of lumens <NUM> extending therebetween in fluid communication with a flow distribution element. The plurality of lumens <NUM> 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 the flow distribution element <NUM>. A flow distribution element <NUM> disposed about the elongate member <NUM> includes a plurality of longitudinally adjacent annular chambers <NUM>, each chamber <NUM> having a proximal end, a distal end, and a central lumen <NUM> extending therethrough that receives the elongate member <NUM>. Each chamber <NUM> has one or more radial apertures <NUM> about an outer surface of the chamber <NUM>. Each lumen of the plurality of lumens <NUM> has at least one supply aperture <NUM> in fluid communication with a dedicated chamber for that lumen. A fluid supplied through a device <NUM> of this embodiment flows through the elongate member via the three, radially partitioned lumens of the plurality of lumens <NUM>. The flow within each lumen will exit the lumen through the supply aperture <NUM> of the lumen into the dedicated chamber <NUM>. The flow will then exit the chamber <NUM> through the radial apertures <NUM> and out of the device <NUM>. Dividing the flow within the plurality of lumens <NUM> to separate chambers <NUM> each having their own radial apertures <NUM> helps to produce a balanced flow to the radial apertures <NUM> and spray from the radial apertures <NUM>. Each of the plurality of lumens <NUM> of the elongate member is dedicated to a respective chamber <NUM> and has at least one dedicated supply aperture <NUM> in fluid communication therewith. The elongate body <NUM> may be mated with a catheter. Each lumen of the plurality of lumens <NUM> of the elongate member <NUM> may terminate at a supply aperture <NUM> associated with its respective annular chamber <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element <NUM> has the flow distribution element <NUM> extending partially along an elongate body <NUM>. The body <NUM> is configured to be inserted into or be integral with a distal end opening of a catheter <NUM>. The body <NUM> has a longitudinal axis, a proximal end, a distal end, and a backstop <NUM> at the distal end. The flow distribution element <NUM> includes a plurality of fins <NUM> extending radially from a longitudinal axis of the elongate body <NUM> that are configured to engage an inner surface of the catheter <NUM>. The backstop <NUM> has a surface <NUM> perpendicular to and facing the distal end opening of the catheter <NUM> when the elongate body <NUM> is inserted into the catheter <NUM>. The surface <NUM> is longitudinally offset from a distal end opening of the catheter <NUM> in a distal direction forming a radial aperture <NUM> around the opening. A <NUM>° aperture <NUM> is created by the space between the surface <NUM> and the distal end of the catheter <NUM>. A flow of fluid through the catheter <NUM> is directed from a substantially axial direction to a substantially radial direction through the aperture <NUM> upon colliding with the surface <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element <NUM> has the flow distribution element extending partially along an elongate body <NUM> and the body <NUM> is configured to be inserted into or integral with a catheter <NUM>. The elongate body <NUM> has a proximal end, a distal end, and a backstop <NUM> at the distal end. The flow distribution element <NUM> includes fins <NUM>. The fins <NUM> gradually extend radially further from a longitudinal axis of the elongate body <NUM> as the fins <NUM> extend along the elongate body <NUM> in the direction of the backstop. The fins <NUM> extend along the elongate body <NUM> in a helical pattern and in a distal direction. The backstop <NUM> is configured to engage the inner surface of the catheter <NUM>. The elongate body <NUM> may engage a catheter <NUM> with apertures <NUM>, which may be radial apertures that receive protrusions on the wall of the catheter <NUM>. Conversely, the protrusions may be on the device and configured be received within notches on the wall of a catheter <NUM>. A flow of fluid through the catheter <NUM> is directed from a substantially axial direction to a substantially radial direction through the apertures <NUM> by the fins <NUM> as well as the elongate body <NUM> transitioning into the backstop <NUM>. The elongate body <NUM> has a slope <NUM> that transitions from the body <NUM> to the backstop <NUM> such that cross-sectional resistance to the flow of fluid increases as the flow translates distally. The helical pattern of the fins <NUM> encourages the flow to rotate, increasing radial flow towards the apertures <NUM> due to centripetal acceleration. The slope <NUM> portion and fins <NUM> of the elongate body <NUM> may be independent of the backstop <NUM> and instead be disposed on an axial shaft and motor assembly. The motor may rotate the slope <NUM> portion and fins <NUM>, directing the flow of fluid generally toward the apertures <NUM>.

With reference to <FIG>, an embodiment of a device with a flow distribution element has an elongate body <NUM> configured to be inserted into a catheter <NUM>. The elongate body <NUM> engages the catheter <NUM> via one or more ridges <NUM> along the elongate body <NUM>. A ring <NUM> may fit into a notch of the catheter <NUM> such that the body <NUM> is held in place. Instead of or in addition to the ring <NUM> and/or ridges <NUM>, the body <NUM> may be fixed into place within the catheter <NUM> via threading, bonding, interference, and the like. The elongate body <NUM> has a proximal end, a distal end, and a backstop <NUM> attached at the distal end. The backstop <NUM> has a concave surface <NUM> facing the distal end opening of the catheter <NUM>. The flow distribution element <NUM> includes a diffuser element <NUM> from the concave surface <NUM> that extends proximally towards a lumen of the catheter <NUM> and against a direction of flow from the opening of the catheter <NUM>. The diffuser element <NUM> has a curved transition from the tip to the concave surface <NUM>. The backstop <NUM> and the flow distribution element <NUM> are configured to be concentrically disposed within or integrated as part of a lumen of the elongate body <NUM>. The concave surface <NUM> is offset from the distal end of the elongate body <NUM>, creating an aperture <NUM>. The aperture <NUM> is oriented <NUM>° proximally from a perpendicular plane to the longitudinal axis of the elongate body <NUM>. This proximal orientation directs flow from the aperture <NUM> 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. The backstop <NUM> may be connected to the elongate body <NUM> by several struts of the diffuser element <NUM> that engage the elongate body <NUM>. The struts of the diffuser element <NUM> distally span the gap of the aperture <NUM>, but are thin enough to not substantially obstruct the aperture <NUM>. The thickness and number of struts in the diffuser element <NUM> may be determined by the desired amount of connection strength between the backstop <NUM> and the elongate body <NUM> and the desired flow of spray from the aperture <NUM>.

In various embodiments, the apertures may include multiple rows of apertures, such as, e.g., <NUM> rows spaced about <NUM> millimeters apart. The apertures may comprise a variety of shapes and sizes, such as, e.g., <NUM> equally spaced holes of about <NUM>" (about <NUM> millimeters) diameter. The apertures may be oriented radially, proximally, or distally, or some combination thereof.

Claim 1:
A device for a radial spray catheter (<NUM>, <NUM>), comprising:
a body (<NUM>) 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 (<NUM>) along the longitudinal axis from the proximal end of the body (<NUM>) into at least the mid-portion of the body (<NUM>);
one or more apertures (<NUM>) distributed about the exterior radial surface of the body (<NUM>); and
a flow distribution element in fluid communication with the central lumen and the one or more apertures,
wherein the flow distribution element comprises a distribution lumen (<NUM>) that extends from the central lumen to the distal end of the body (<NUM>) and is in fluid communication with the central lumen, and wherein the distribution lumen (<NUM>) includes a plurality of the apertures (<NUM>) along the longitudinal axis,
characterised by
a spring (<NUM>) within the distribution lumen having a distal component associated with the distal end of the body (<NUM>) and a proximal component associated with an oscillator body (<NUM>), whereby the oscillator body (<NUM>) oscillates in the distribution lumen with flow pushing against a restoring force of the spring (<NUM>) to distribute the flow to the apertures (<NUM>).