Patent Description:
The present invention relates to medical ablation, fragmentation, and cutting, and, more particularly, to a microcavitation system, device, and ultrasonic probe assembly for generating directional microcavitation.

Medical procedures, such as vascular occlusion crossing and/or atherectomy, may utilize ultrasonic energy to cross and/or break up the vascular occlusion through the vibration of a catheter tip engaged with the vascular occlusion. Also, interventional oncology may utilize a mechanical cutting instrument, thermal ablation, or cryogenic techniques, for the removal of a tumor or cancerous lesion.

Acoustic cavitation is the formation and collapse of bubbles in liquid irradiated by intense ultrasound. The speed of the bubble collapse sometimes reaches the sound velocity in the liquid. Accordingly, the bubble collapse becomes a quasi-adiabatic process. Violent bubble collapse during cavitation causes extreme local temperatures, heating/cooling rates and pressures, producing free radicals and giving rise to many chemical (sonochemical) reactions (e.g., oxidation of pollutants, sterilization, polymerization, desulfurization, long-chain molecule degradation, etc.).

What is needed in the art is a microcavitation system, device, and ultrasonic probe assembly for generating directional microcavitation that may be used, for example, in vascular and interventional oncology procedures.

<CIT> discloses a probe comprising an elongated member and a cannula. From <FIG> and <FIG> of this document, a cavitation generation member may be defined by a wall at the distal end of the cannula.

<CIT> discloses an ultrasound delivery device including a part having a wall defining a plurality of apertures provided in order to form a jet striking skin surface. By virtue of capability of skin to heal and close tiny holes in a short period of time, the apparatus would reduce the discomfort to the patient. <CIT>, <CIT>, <CIT>, <CIT>, and <CIT> illustrate other devices close to the technical field of the present invention.

The present invention provides a microcavitation system, device, and ultrasonic probe assembly for generating directional microcavitation that may be used, for example, in vascular and interventional oncology procedures.

An advantage of the present invention is that directional microcavitation is generated to produce directional fluid jetting streams that are emitted longitudinally from a distal end of the cannula of the ultrasonic probe assembly to provide controlled and directional cutting and/or ablation.

Another advantage is that the microcavitation is directional via the generated cavitation column, thereby providing better tumor margin outcomes than many other tumor removal techniques.

Yet another advantage is that the energy density of the microcavitation is much less destructive to tissue that surrounds the tumor margin, as compared with the harsh environment of RF, thermal, or microwave ablation.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate an embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

Referring now to the drawings, and more particularly to <FIG>, there is shown a microcavitation system <NUM> in accordance with an embodiment of the present invention. Microcavitation system <NUM> generally includes a console <NUM> and an ultrasonic microcavitation device <NUM>. Ultrasonic microcavitation device <NUM> may be used, for example, for interventional oncology or vascular procedures.

Console <NUM> is connected in electrical communication with ultrasonic microcavitation device <NUM> via an electrical cable <NUM>, e.g., a multi-conductor cable. Console <NUM> is connected in fluid communication with ultrasonic microcavitation device <NUM> via a fluid conduit <NUM>, e.g., a flexible tube or hose. Console <NUM> may include multiple components in a single housing unit or in separate housing units. In the present embodiment, console <NUM> may include a user interface <NUM>, a controller <NUM>, an ultrasonic signal generator <NUM>, and a fluid source <NUM>.

User interface <NUM> is connected to controller <NUM> via an electrical conductor <NUM>-<NUM>, e.g., a multi-wire cable or USB, to provide electrical and communication interconnection. Alternatively, user interface <NUM> may be a wireless link, e.g., Bluetooth, which is communicatively coupled to controller <NUM>. User interface <NUM> may include, for example, a touchscreen display and associated input and output processing circuitry. Touchscreen display may include, for example, a liquid crystal display (LCD) or a light-emitting diode (LED) display. Alternatively, user interface <NUM> may be in the form of a laptop computer or tablet. User interface <NUM> is configured to generate control signals based on user input. For example, a user may operate user interface <NUM> to provide the control signals to controller <NUM> to initiate and/or terminate operation of ultrasonic signal generator <NUM>, and/or to selectively start, stop, or control the fluid feed rate of fluid source <NUM>.

Controller <NUM> is electrically connected and communicatively coupled to user interface <NUM> via electrical conductor <NUM>-<NUM>, e.g., a multi-wire cable or USB. Also, controller <NUM> is electrically connected and communicatively coupled to ultrasonic signal generator <NUM> via an electrical conductor <NUM>-<NUM>, e.g., a multi-wire cable or USB, and controller <NUM> is electrically connected and communicatively coupled to fluid source <NUM> via an electrical conductor <NUM>-<NUM>, e.g., a multi-wire cable or USB. Each of electrical conductors <NUM>-<NUM>, <NUM>-<NUM> is configured to carry respective output control signals.

Controller <NUM> includes a processor circuit <NUM>-<NUM>, interface circuitry <NUM>-<NUM>, and an electronic memory circuit <NUM>-<NUM>. Controller <NUM> executes program instructions to process signals received from user interface <NUM>, executes program instructions to provide output control signals via interface circuit <NUM>-<NUM> to ultrasonic signal generator <NUM> to control the operation of ultrasonic signal generator <NUM>, and executes program instructions to provide output control signals via interface circuit <NUM>-<NUM> to fluid source <NUM> to control the operation of fluid source <NUM>.

More particularly, processor circuit <NUM>-<NUM> of controller <NUM> may include one or more programmable microprocessors and associated circuitry, such as an input/output interface, clock, buffers, memory, etc. Processor circuit <NUM>-<NUM> may be programmed, e.g., through software or firmware stored in electronic memory circuit <NUM>-<NUM>, to execute program instructions to process received input data, and to generate and send output data.

Interface circuitry <NUM>-<NUM> includes input and output circuits to facilitate electrical connection and data transfer with user interface <NUM>, ultrasonic signal generator <NUM>, and fluid source <NUM>.

Electronic memory circuit <NUM>-<NUM> is an electronic non-transitory memory having a plurality of data storage locations, as is well known in the art. Electronic memory circuit <NUM>-<NUM> may include one or more of volatile memory circuits, such as random access memory (RAM), and non-volatile memory circuits, such as read only memory (ROM), electronically erasable programmable ROM (EEPROM), NOR flash memory, NAND flash memory, etc. Electronic memory circuit <NUM>-<NUM> may be used, for example, to store program instructions to be executed by processor circuit <NUM>-<NUM> of controller <NUM> of console <NUM>.

Ultrasonic signal generator <NUM> is typical of that known in the art, and may be adjustable via user interface <NUM> and controller <NUM> to produce an ultrasonic electrical signal in the form of an ultrasonic excitation signal, in a frequency range of <NUM>-<NUM>, and is adjustable via user interface <NUM> and controller <NUM> to produce a variable electrical power output of the ultrasonic excitation signal by adjusting the amplitude of the output voltage and/or current, and/or by adjusting the frequency and/or duty cycle, of the ultrasonic excitation signal.

As shown in <FIG>, ultrasonic microcavitation device <NUM> includes a handle <NUM> and an ultrasonic probe assembly <NUM>. Handle <NUM> includes a housing <NUM> that contains an ultrasonic transducer <NUM> that is mounted internally to housing <NUM>. Housing <NUM> has an outer shape and size to facilitate being grasped by an operator during a medical procedure, such as for example, an oncological or occlusion related procedure.

Ultrasonic transducer <NUM> may be, for example, a piezoelectric-type transducer. Ultrasonic transducer <NUM> of handle <NUM> is electrically connected to ultrasonic signal generator <NUM> by electrical cable <NUM>, and is configured to receive and convert the ultrasonic excitation signal generated by ultrasonic signal generator <NUM> into ultrasonic vibrational energy, which may be in a frequency range corresponding to that of the ultrasonic excitation signal generated by ultrasonic signal generator <NUM>. For example, if the frequency of the ultrasonic excitation signal generated by ultrasonic signal generator <NUM> and supplied to ultrasonic transducer <NUM> is <NUM>, then the vibrational frequency of the output of ultrasonic transducer <NUM> correspondingly may be <NUM>.

Ultrasonic probe assembly <NUM> is mechanically connected to housing <NUM> of handle <NUM>. Ultrasonic probe assembly <NUM> generally includes an ultrasonic transmission member <NUM>, a cannula <NUM>, and a cannula sheath <NUM>, wherein cannula sheath <NUM> is an optional component of ultrasonic probe assembly <NUM>. Also, optionally and alternatively, ultrasonic transmission member <NUM> may be a component of handle <NUM>.

In a case wherein ultrasonic microcavitation device <NUM> is intended to be fully disposable, then ultrasonic probe assembly <NUM> may be permanently attached to handle <NUM>. However, if it is desired that handle <NUM> of ultrasonic microcavitation device <NUM> be reusable, then ultrasonic probe assembly <NUM> may be made to be removably attachable to handle <NUM>, e.g., by a screw coupling or snap connection.

Cannula <NUM> is a part of ultrasonic probe assembly <NUM>, and thus, is connected to housing <NUM> of handle <NUM>. In the present embodiment, cannula <NUM> may be made of a biocompatible metal, such as stainless steel, and is configured to be semi-rigid, i.e., allowing some degree of flexing without permanent deformation. However, it is contemplated that other more flexible and/or non-metal biocompatible materials may be used, depending upon the medical application.

Referring also to <FIG>, cannula <NUM> has a tubular side wall <NUM>-<NUM>, a cannula lumen <NUM>-<NUM>, a fluid input port <NUM>-<NUM>, a proximal end <NUM>-<NUM>, a distal end <NUM>-<NUM>, and a distal end portion <NUM>-<NUM>.

Proximal end <NUM>-<NUM> of cannula <NUM> is connected to housing <NUM> of handle <NUM>.

Distal end portion <NUM>-<NUM> is configured to define a cavitation generation chamber <NUM> that distally terminates at the distal end <NUM>-<NUM>. Cavitation generation chamber <NUM> has a distal end wall <NUM>-<NUM> located at distal end <NUM>-<NUM> of cannula <NUM>. Distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM> is configured as a sieve <NUM>-<NUM> to define a plurality of apertures <NUM>-<NUM>. A longitudinal axis <NUM> of cannula <NUM> longitudinally extends through each of cannula lumen <NUM>-<NUM>, cavitation generation chamber <NUM>, and sieve <NUM>-<NUM>.

Cannula <NUM> further includes an annular protrusion <NUM>-<NUM> in the cannula lumen <NUM>-<NUM> that extends inwardly from the tubular side wall <NUM>-<NUM>. Annular protrusion <NUM>-<NUM> defines a proximal termination end of distal end portion <NUM>-<NUM>, and provides a demarcation between cannula lumen <NUM>-<NUM> and cavitation generation chamber <NUM>. Stated differently, annular protrusion <NUM>-<NUM> is configured to define a distal termination end of cannula lumen <NUM>-<NUM> and is configured to define an aft end of the cavitation generation chamber <NUM>. In addition, annular protrusion <NUM>-<NUM> tends to direct the flow stream of fluid entering cavitation generation chamber <NUM> away from tubular side wall <NUM>-<NUM> of cannula <NUM>.

Fluid input port <NUM>-<NUM> of cannula <NUM> may be in the form of a Y-connector that provides fluid access to, and is connected in fluid communication with, cannula lumen <NUM>-<NUM>. Fluid input port <NUM>-<NUM> is connected by fluid conduit <NUM> to fluid source <NUM>, such as a saline injector, having a pump <NUM>-<NUM>. For example, fluid source <NUM> may be configured to deliver a fluid <NUM>, e.g., sterile saline, to cannula lumen <NUM>-<NUM> of cannula <NUM>. Fluid <NUM> may serve to cool ultrasonic transmission member <NUM> and cannula <NUM>. Moreover, fluid <NUM> is the fluid used for the generation of microbubble cavitation energy by ultrasonic microcavitation device <NUM> in cavitation generation chamber <NUM>.

In the present embodiment, cannula lumen <NUM>-<NUM> is an elongate lumen that longitudinally extends within cannula <NUM> from proximal end <NUM>-<NUM> up to, but not into, cavitation generation chamber <NUM> of distal end portion <NUM>-<NUM>. Cannula lumen <NUM>-<NUM> may be formed as a central lumen, relative to the diameter, of cannula <NUM>. Cannula lumen <NUM>-<NUM> is sized and configured to receive and carry ultrasonic transmission member <NUM>. Also, cannula lumen <NUM>-<NUM> is sized and configured to deliver fluid <NUM> to cavitation generation chamber <NUM>. However, it is contemplated that cannula lumen <NUM>-<NUM> may alternatively be formed as multiple lumens in cannula <NUM>, wherein a separate fluid lumen may deliver the fluid <NUM> to cavitation generation chamber <NUM>.

Ultrasonic transmission member <NUM> may be in the form of an elongate flexible metal wire, e.g., nitinol, which is sometimes also referred to in the art as a core wire. Ultrasonic transmission member <NUM> is located in, and longitudinally extends within, cannula lumen <NUM>-<NUM> of cannula <NUM>. Ultrasonic transmission member <NUM> has a first end portion <NUM>-<NUM> and a second end <NUM>-<NUM> spaced apart from the first end portion <NUM>-<NUM>. Second end <NUM>-<NUM>, i.e., the distal end, of ultrasonic transmission member <NUM> distally terminates at a location proximal to cavitation generation chamber <NUM>.

First end portion <NUM>-<NUM> of the ultrasonic transmission member <NUM> is mechanically connected to ultrasonic transducer <NUM>, e.g., by a sonic connector, to receive the vibrational energy from ultrasonic transducer <NUM> so as to produce a vibrational motion of ultrasonic transmission member <NUM>. Thus, ultrasonic transducer <NUM> generates vibratory energy at a vibratory energy level corresponding to the electrical energy output level of the ultrasonic excitation signal generated by ultrasonic signal generator <NUM>. The vibrational motion of ultrasonic transmission member <NUM> may be a combination of longitudinal and transverse vibration.

For example, if the frequency of the ultrasonic excitation signal generated by ultrasonic signal generator <NUM> and supplied to ultrasonic transducer <NUM> is <NUM>, then the vibrational frequency of a longitudinal and/or transverse vibrational motion of distal end portion <NUM>-<NUM> of ultrasonic transmission member <NUM> correspondingly may be <NUM>. In this example, each of the longitudinal and/or transverse displacement of second end <NUM>-<NUM> of ultrasonic transmission member <NUM> may be approximately <NUM> micrometers when the ultrasonic excitation signal generated by ultrasonic signal generator <NUM> and supplied to ultrasonic transducer <NUM> is <NUM>. The amount of displacement, and the resulting fluid cavitation, may be increased by increasing the ultrasonic excitation signal frequency and/or the electrical power of the ultrasonic excitation signal supplied to ultrasonic transducer <NUM>.

Fluid <NUM> flows through cannula lumen <NUM>-<NUM> of cannula <NUM> around and across ultrasonic transmission member <NUM>, and enters cavitation generation chamber <NUM>. Upon activation of ultrasonic transmission member <NUM>, the fluid <NUM> in cavitation generation chamber <NUM> of cannula <NUM> undergoes cavitation to generate within cavitation generation chamber <NUM> a column of microcavitation bubbles <NUM> that is directed toward distal end <NUM>-<NUM> of cannula <NUM>. The plurality of apertures <NUM>-<NUM> of sieve <NUM>-<NUM> defined by distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM> are configured, e.g., sized and shaped, to eject longitudinally directed fluid jetting streams <NUM>-<NUM> along (i.e., on and substantially parallel to) longitudinal axis <NUM>. Due to the fluid dynamics of the generation and collapse of the microcavitation bubbles <NUM> in cavitation generation chamber <NUM>, the longitudinally directed fluid jetting streams <NUM>-<NUM> are ejected along longitudinal axis <NUM> through the plurality of apertures <NUM>-<NUM> of sieve <NUM>-<NUM> defined by distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM>. The fluid jetting streams <NUM>-<NUM> emitted from the plurality of apertures <NUM>-<NUM> of sieve <NUM>-<NUM> defined by distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM> are highly directional micro-jets having a high velocity, e.g., approximately <NUM> meters per second, and produce high shear forces, thereby being adaptable to a wide range of medical procedures requiring ablation, cutting, or fragmenting of a material substance, such as for example, in performing vascular occlusion crossing, atherectomy, and interventional oncology procedures.

Due to the potential heating of cannula <NUM> during activation of ultrasonic microcavitation device <NUM>, cannula sheath <NUM> may be included in ultrasonic microcavitation device <NUM> to provide additional cooling of cannula <NUM>. In the present embodiment, cannula sheath <NUM> is positioned over cannula <NUM> in a region proximal to cavitation generation chamber <NUM>. In some embodiments, cannula sheath <NUM> may be permanently attached to cannula <NUM>. Cannula sheath <NUM> includes a cooling jacket <NUM> configured as a microtube arrangement <NUM>-<NUM> that surrounds tubular side wall <NUM>-<NUM> of the cannula <NUM> in a region proximal to cavitation generation chamber <NUM>. Microtube arrangement <NUM>-<NUM> of cooling jacket <NUM> may be configured, for example, in a crisscross or spiral pattern. Microtube arrangement <NUM>-<NUM> is configured to receive a flow of a cooling fluid, such as sterilized saline, and accordingly, may utilize fluid <NUM> delivered by fluid source <NUM> as the cooling fluid. As such, microtube arrangement <NUM>-<NUM> may be connected in fluid communication with fluid source <NUM>.

In operation, a user activates microcavitation system <NUM> by providing an input at user interface <NUM>. The user input may be, for example, the depression of a pushbutton or a selection made from a displayed menu. User interface <NUM> then sends an input signal to controller <NUM>.

Controller <NUM> executes program instructions to process the input signal from user interface <NUM>, and executes program instructions to generate and supply output signals to ultrasonic signal generator <NUM> and to fluid source <NUM>, which in turn triggers a series of events related to the operation of ultrasonic microcavitation device <NUM>, culminating in the generation of the longitudinally directed fluid jetting streams <NUM>-<NUM> that are emitted from the plurality of apertures <NUM>-<NUM> of sieve <NUM>-<NUM> defined by distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM> of cannula <NUM>.

In particular, controller <NUM> produces and outputs a generator control signal to ultrasonic signal generator <NUM> to cause the ultrasonic signal generator <NUM> to generate an ultrasonic excitation signal having a predefined electrical energy output level. The ultrasonic excitation signal is supplied to ultrasonic transducer <NUM>, wherein ultrasonic transducer <NUM> generates vibratory energy at a vibratory energy level corresponding to the electrical energy output level of the ultrasonic excitation signal. Ultrasonic transducer <NUM>, in turn, supplies the vibratory energy to ultrasonic transmission member <NUM> to activate the ultrasonic transmission member to produce both longitudinal and transverse motion at second end <NUM>-<NUM>, i.e., the distal end, of ultrasonic transmission member <NUM>.

Also, controller <NUM> produces and outputs a fluid control signal to the fluid source <NUM> to control an amount of flow (e.g., volume per unit time or speed/velocity of a given volume) of fluid <NUM> generated by the fluid source <NUM>. Fluid source <NUM> supplies the flow of fluid <NUM> to the fluid input port <NUM>-<NUM> of the cannula <NUM>, and in turn, fluid <NUM> travels through cannula lumen <NUM>-<NUM> to cavitation generation chamber <NUM>.

Upon activation of ultrasonic transmission member <NUM>, fluid <NUM> in cavitation generation chamber <NUM> of cannula <NUM> undergoes cavitation to generate within cavitation generation chamber <NUM> a column of microcavitation bubbles <NUM> that is directed toward distal end <NUM>-<NUM> of cannula <NUM>. Due to the fluid dynamics of the generation and collapse of the microcavitation bubbles <NUM> in cavitation generation chamber <NUM>, fluid jetting streams <NUM>-<NUM> are ejected through the plurality of apertures <NUM>-<NUM> of sieve <NUM>-<NUM> defined by distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM>. Accordingly, the directional microcavitation generated in cavitation generation chamber <NUM> produces directional fluid jetting streams <NUM>-<NUM> that are emitted longitudinally from a distal end <NUM>-<NUM> of cannula <NUM> of ultrasonic probe assembly <NUM> to provide controlled and directional cutting and/or ablation by ultrasonic microcavitation device <NUM> along longitudinal axis <NUM>.

The user may supply further inputs to user interface <NUM> to adjust an aggressiveness (i.e., velocity and/or pressure) at which the fluid jetting streams <NUM>-<NUM> are emitted, i.e., ejected, through the plurality of apertures <NUM>-<NUM> in distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM>. For example, the user may supply a further input to user interface <NUM> to select an electrical power output of the ultrasonic excitation signal that is generated by ultrasonic signal generator <NUM> and supplied to ultrasonic transducer <NUM> of ultrasonic microcavitation device <NUM>, so as to control the vibratory energy transferred by ultrasonic transmission member <NUM> to the fluid in cavitation generation chamber <NUM>, so as to control the aggressiveness of the fluid jetting streams <NUM>-<NUM> that are emitted, i.e., ejected, through the plurality of apertures <NUM>-<NUM> in distal end wall <NUM>-<NUM> of cavitation generation chamber <NUM>.

Claim 1:
An ultrasonic probe assembly (<NUM>), comprising:
an ultrasonic transmission member (<NUM>) having a first end portion (<NUM>-<NUM>) and a second end (<NUM>-<NUM>) spaced apart from the first end portion (<NUM>-<NUM>); and
a cannula (<NUM>) having a tubular side wall, a cannula lumen (<NUM>-<NUM>), a fluid input port (<NUM>-<NUM>), a proximal end (<NUM>-<NUM>), a distal end (<NUM>-<NUM>), and a distal end portion (<NUM>-<NUM>), wherein:
the ultrasonic transmission member (<NUM>) is located in the cannula lumen (<NUM>-<NUM>);
the fluid input port (<NUM>-<NUM>) of the cannula (<NUM>) is connected in fluid communication with the cannula lumen (<NUM>-<NUM>); and
the distal end portion (<NUM>-<NUM>) of the cannula (<NUM>) is configured to define a cavitation generation chamber (<NUM>), the cavitation generation chamber (<NUM>) having a distal end wall (<NUM>-<NUM>) at the distal end (<NUM>-<NUM>) of the cannula (<NUM>), characterized in that the distal end wall (<NUM>-<NUM>) is configured as a sieve (<NUM>-<NUM>) to define a plurality of apertures (<NUM>-<NUM>) configured to eject fluid jetting streams, and
the second end (<NUM>-<NUM>) of the ultrasonic transmission member (<NUM>) distally terminates at a location proximal to the cavitation generation chamber (<NUM>).