The present application relates to an applicator comprising a pressure pulse concentrator which is adapted to concentrate a planar pressure pulse, and a conduction device, which is adapted to conduct the concentrated planar pressure pulse to a delivery location.

Pressure pulses or shock waves are used for treatment of different medical conditions. For example, high-energy focused shock waves are used in lithotripsy, whereby the energy of the Shockwaves is used to destroy kidney stones or gallstones in a patient.

Recent developments suggest the usage of pressure pulses with a lower intensity than those used in lithotripsy for example for promotion of tissue regeneration. Among others, this kind of application is used in urology and applied to medical conditions in the pelvic floor and male and female sexual organs. The associated application sites for pressure pulses on the human body are comparatively difficult to reach. As a general requirement, devices for generating the pressure pulses require a minimum size and weight to be able to produce pressure pulses with the required energy density and focusing means. Said required size impedes the use of pressure pulses at application sites that are difficult to reach.

Single pressure pulses, to which the present invention refers, are substantially different from ultrasound waves. The pressure pulse is characterized by one very large pressure amplitude that includes a very abrupt rise of pressure and a subsequent abrupt decrease of the pressure to zero with only little following after-oscillation. When the pressure pulse propagates within a medium, for example water, the effect of steepening occurs, raising the maximum amplitude by shortening the total pulse. This effect relies on the variability of the speed of sound in dependency of the pressure within a fluid.

To the contrary, ultrasound is characterized by a periodic pressure fluctuation in multiple cycles within a limited bandwidth.

DE 10340624 A1 discloses a source of pressure pulses with the features of the preamble of claim 10. A planar pressure pulse is generated by a flat coil and then focused by an acoustic lens with the two concave outer surfaces. The focus of the device is dependent on the characteristic of the lens. The described device has a generally cylindrical shape resembling the cross section of the flat coil. The patient-sided end of the device, at which the focused pressure pulse exits the device is closed by a flexible coupling bag filled with water, that is adapted to contact the skin of the patient close to the treatment zone.

The functional principle of a flat coil in combination with an attached conductive metallic membrane for generation of a pressure pulse is based on the physical principle of electromagnetic induction. A short flow of electrical current is led through the flat coil, which then builds up a strong magnetic field. This magnetic field induces a counter-directed current in the membrane. The so-called Lorentz-force pushes the metallic membrane, which in turn generates the pressure pulse within the fluid.

US 2008/02281 12 discloses a Shockwave conductor. A Shockwave is generated pursuant to the principle of electrohydraulic Shockwave generation. Within a conduction medium, for example water, an electrical discharge is caused between two electrode tips causing a very hot plasma to develop which expands in the form of an explosion and thereby initiates the pressure pulse. This pressure pulse initially propagates in the form of an expanding sphere. Said spherical Shockwave can be transformed to a planar Shockwave by a parabolic shaped mirror. To focus the resulting parallel pressure pulse, it is necessary to utilize an acoustic lens or parabolic reflector. Attentively, the spherical pressure pulse can be instantly focused by an accordingly shaped reflector. That focus of the Shockwave is set close to an inlet of a Shockwave tube, in which the focused pressure pulse is conducted to an application site.

Instead of using a reflector or acoustic lens, EP 0183236 suggests using a curved electromagnetic induction coil in combination with a curved membrane, whose design is self- focusing. Focusing of the Shockwave is attained by the distinctive shape of the coil and membrane. Pursuant to the principles of geometrical optics, the outermost rays of the generated Shockwaves propagate in parallel to the walls of a cone shaped chamber and are concentrated in a focus at the target site.

US 5,152,768 describes an example for a pressure pulse generated by electrical discharge. The spherically propagating pressure pulse is led through a nozzle within a flowing working fluid that is also conducted through the nozzle. The nozzle is not disclosed to have any focusing effects but simply functions as a baffle, cutting off, by absorption and reflection, parts of the pressure pulse, which would otherwise be conducted sideways.

US 6,007,499 discloses methods and apparatuses for the application of high intensity focused ultrasound including examples of conducting focusing and reflecting ultrasound waves. The principles disclosed therein solely rely on geometrical optics with straight ray propagation, neglecting diffraction effects.

It is an object of the present invention to suggest an applicator comprising a pressure pulse concentrator which is adapted to concentrate a planar pressure pulse, and a conduction device, which is adapted to conduct the concentrated planar pressure pulse to a delivery location. The applicator is characterized in that the conduction device comprises a conduction tube and at least one reflector provided within the conduction tube adapted to reflect planar pressure pulses into at least one sideward direction.

However the pressure pulse concentrator and/or the conduction device constitute separately an invention as such. The features disclosed in the following for the complete applicator may be also present, as long as this is not technologically impossible, for each of the pressure pulse concentrator and/or the conduction device. Also the features which are disclosed in the following for the pressure pulse concentrator and/or the conduction device may be present in the applicator.

In the following a method for generating a concentrated planar pressure pulse is also described. The method comprises the steps of creating a generally planar pressure pulse with a direction of propagation, and increasing the pressure amplitude of the pressure pulse with an amplification means.

In this method the pressure pulse is transmitted towards a tapered wall section of the amplification means, which is inclined relative to the direction of propagation, wherein a boundary area of the pressure pulse collides with the tapered wall section and the pressure amplitude of the pressure pulse is accumulated in the boundary area.

The method may be executed with the disclosed devices. E.g. the amplification means may be constituted by the pressure pulse concentrator.

The described method may form a separate invention. All product related features may be formulated in a method related way for the inventive method.

However both the method and the corresponding device(s) allow improved access to treatment sites which are difficult to reach.

It is in particular provided an applicator, wherein the conduction device may have a configuration that it emits the concentrated planar pressure pulse through an opening (in the sidewall).

The opening may be closed by a window, which allows the concentrated planar pressure pulse to be emitted in a planar manner to the exterior of the applicator.

In the applicator the pressure pulse concentrator and the conduction device may be a unitary piece, wherein an elongated portion of the conduction device, which is provided distal from the pressure pulse concentrator, is adapted to be inserted in a patient's cavity. In the applicator, the conduction device may be a separate piece, separate from the pressure pulse concentrator and adapted to be connected to an outlet of a concentration chamber of the pressure pulse concentrator.

The concentration chamber may contain a conduction medium configured to conduct a planar pressure pulse from an inlet to an outlet of the concentration chamber and to increase the pressure amplitude of the pressure pulse.

The conduction device may have an elongated portion, which is provided distal from the pressure pulse concentrator and adapted to be inserted in a patient's cavity.

The applicator may be adapted so that the conduction medium is received in an unitary chamber constituted by the concentration chamber of the pressure pulse concentrator and a conduction tube of the conduction device.

The applicator may comprise a reflector piece, which is constituted by an insert, which is placed in the conduction tube. The reflector piece preferably has the configuration of an inverted cone.

The applicator may further comprises a pressure pulse generating means, which is provided at a rear side of the pressure pulse concentrator, which generates planar pressure pulses, which traverse first through a cylindrical part upstream of the concentration chamber, wherein the planar pressure pulse is concentrated and remains basically planar while its amplitude being enhanced in the concentration chamber.

The applicator may be configured such that the relation between the longitudinal extension of the concentration chamber to the conduction tube is between 1 :1 and 1 :5. Further preferred values are 1 :1.5; 1 :2; 1 :3; 1 :4.

In the following some technical effects of the pressure pulse concentrator are described.

When the boundary areas of the planar pressure pulse collide with the tapered wall section having an inclination angle, a snowplow effect occurs. This effect is based on a combination of acoustic wave reflection and fluid dynamics. Instead of a behavior pursuant to the rules of geometrical optics, the fluid dynamic mechanisms for pulse concentration are similar to the transient state of a De Laval-Nozzle. The components of the pressure pulse that are reflected at the tapered wall section overlay and mingle with the incoming components of the pressure pulse. The use of tapered wall sections for concentrating the pressure pulse allows a reliable, lightweight and small assembly that is easy to handle. This allows a reliable and steady increase of the pressure amplitude, while the cross-section of the pressure pulse can be narrowed to focus the pressure pulse. The focusing can be performed precisely, as it is possible to maintain a short pulse width of the pressure pulse and a high energy density within the concentration zone. After concentration, the initially planar pressure pulse remains generally planar with a small pulse width. This may facilitate further conduction of the concentrated pressure pulse to an application site.

In particular, the initial pulse width of the pressure pulse may be more than 1 s and less than 100 s, in particular at least 5 s and less than 100 s. This promotes the effect of increasing the pressure amplitude and helps to achieve a stable and short pressure pulse width.

Possibly, the cross section of the pressure pulse may be reduced by 50 to 80 % between an inlet and an outlet of the amplification means. This allows a high increase of the pressure pulse amplitude. This promotes the amplification effect of the pressure amplitude and focuses the cross section of the pressure pulse to facilitate targeting an application zone of the pressure pulse.

The inclination angle between the tapered wall section and the direction of propagation of the planar pressure pulse may be more than 20 degrees and not more than 40 degrees. Thereby, a stable pressure pulse wave front and short pulse width are maintained.

The inclination angle between the tapered wall section and the direction of propagation of the planar pressure pulse may be variable, wherein, in particular, the inclination angle increases following an essentially parabolic curve. This allows reflecting parts of the pressure pulse towards a common focal zone within the propagation path of the concentrated planar pressure pulse to further promote amplification of the pressure pulse.

The concentrated planar pressure pulse may be conducted through an elongated conduction tube after exiting the amplification means. This allows conducting the concentrated pressure pulse to an application site distant from the site where the pressure pulse is initially generated and concentrated. In particular, the conduction tube can be used to access treatment sites that are difficult to reach. For example, the conduction tube could be adapted to be inserted into body openings of a patient.

In particular, a direction of propagation of the concentrated planar pressure pulse may be altered within the conduction tube. This increases the ability of reaching different treatment sites, as the initial direction of propagation of the concentrated pressure pulse when entering the conduction tube may be different from a terminal direction of propagation of the pressure pulse when exiting the conduction tube. The concentrated planar pressure pulse may be reflected within the conduction tube. Due to the reflection, the angle between the direction of propagation when entering and when exiting the conduction tube may be adjusted more freely. For example, the pressure pulse could exit the conduction tube in a sideways direction of the conduction tube.

The concentrated pressure pulse may be split and conducted in at least two different directions within the conduction tube. For example, this allows applying the pressure pulse to multiple target zones or to one large target zone.

Due to the inclination of the tapered wall section, the planar pressure pulse collides with the tapered wall section. At those border areas of the planar pressure pulse that get in contact with the tapered wall section, a snowplow effect occurs. This effect is more based on a principle based on fluid dynamics, pursuant to which fluid is pushed inwards away from the tapered wall section and has little effect on the wave front of the pressure pulse. Pursuant to the principles of acoustics, components of the pressure pulse are reflected at the inclined wall. The reflected components overlay and mingle with the main pressure pulse.

Due to these effects, the pressure amplitude of the pulse is increased where it is in contact with the tapered wall. The assembly can be realized with a comparatively light weight and small size.

The generated concentrated pressure pulses are planar and thus suitable for further conduction to an application site.

The tapered wall section of the concentration chamber may be shaped as a blunt cone. This supports the generation of a symmetric, round and homogeneous pressure pulse.

In particular, a cross section of the outlet of the concentration chamber may be 20 to 50 % of the cross section of the inlet. This supports providing a high amplitude while maintaining a short pulse width and stable pressure pulse front.

Possibly, an inclination angle between the tapered wall section and the direction of propagation is more than 20 degrees and not more than 40 degrees. This promotes a high efficiency of the concentration effect within the concentration chamber in order to attain high pressure amplitudes.

Pursuant to one exemplary implementation, an inclination angle between the direction of propagation of the pressure pulse and the tapered wall section may vary, wherein in particular, the shape of the tapered wall section can follow an essentially parabolic curve. Thereby, components of the pressure pulse that are reflected and do not maintain in the boundary area can be focused to further increase the pressure amplitude of the concentrated pressure pulse.

In the following some technical effects of the conduction device are described.

The conduction tube may have an orifice connected to an outlet of the means for creating concentrated pressure pulses. By use of the conduction tube, a concentrated pressure pulse may be conducted to an application site distant from the source of the pressure pulse. In particular, medical treatment of regions that are difficult to access for devices generating pressure pulses, could be reached more easily with a conduction tube. For example, the conduction tube could be sized and adapted to be inserted into a patient's body opening.

In one embodiment, a reflector may be provided within the conduction tube adapted to reflect planar pressure pulses to a sideward direction. This increases the ability of the device to target different application sites, in particular those that are difficult to reach.

Possibly, the orientation and/or position of the reflector may be changeable. This allows adapting the conduction tube to different target sites for pressure pulses.

For example, the reflector may comprise at least two reflection surfaces provided in an angle relative to each other configured to split the pressure pulse and reflect it in at least two different directions. This allows targeting different application sites or one large application site with one initial pressure pulse.

In particular a cross section of the conduction tube is substantially constant in a direction of propagation of the pressure pulse within the conduction device. This promotes conduction of a stable pressure pulse with little influence of the outer walls of the conduction tube on the quality of the pressure pulse. In can further facilitate handling of the conduction tube, for example if it is intended for insertion into a body opening.

Below, the invention shall the explained in view of a several embodiments:

Fig. 1 shows a cross-sectional view of a pressure pulse concentrator with a plane electromagnetic coil and membrane for pulse generation and a conical concentration chamber.

Fig. 2 shows a conduction tube with a reflection element.

Fig. 3 shows a pressure pulse concentrator comprising a combination of a pressure pulse concentrator as shown in fig. 1 and a conduction tube as shown in fig. 2.

Fig. 4 schematically visualizes the snow-plow effect within a pressure pulse concentrator. Identical reference numbers shall be used for corresponding or identical features within the embodiments.

The pressure pulse concentrator 1 as shown in fig. 1 comprises a planar pulse generator 2, which is schematically shown. The planar pulse generator comprises a flat electromagnetic coil. When applied with an electric current, the coil generates a strong magnetic field. The magnetic field is pushing a metallic foil which is forced to perform an abrupt movement and thereby initiates the pulse. The planar pulse generator is adapted to create planar pressure pulses having a linear direction of propagation 3 that is generally perpendicular to a plane surface of the planar pulse generator. In alternative embodiments, other techniques for generating planar pressure pulses may be used.

The planar pressure pulse, initially generated by the planar pulse generator 2 is at first traveling through a relatively short distance of a cylindrical part 4 of the pressure pulse concentrator and is then entering a concentration chamber 5, which has the shape of a blunt cone via an inlet 6. At its opposite side, the concentration chamber comprises an outlet 7 through which the concentrated pressure pulses exit the concentration chamber 5. The blunt cone is formed by inclined conical wall sections 22 that are inclined relative to the direction of propagation 3 of the pressure pulse by an inclination angle (a) of 20 to 40 degrees. In alternative embodiments, this angle may be variable or, in particular having the shape of a hyperbolic curve.

Concentration chamber 5 is filled with water. In other embodiments it is also possible to replace the water by other media able to transmit acoustical pressure pulses.

The concentration chamber 5 is made of aluminum, which combines advantageous characteristics in view of the reflection and accumulation of the pressure pulse and at the same time promotes a low weight construction. In alternative embodiments, the walls of the concentration chamber could be made from steel or any other suitable material that is adapted to reflect a pressure pulse transmitted within the medium filling the concentration chamber.

The outlet 7 is closed by a membrane 8, which is made of a polymer and permeable for pressure pulses.

The membrane 8 has an increased lateral extension so as to also cover the complete outer surface of the conical concentration chamber 5 to reduce noise generated during pulse generation which is transmitted to the environment and to enable easy cleaning and disinfection for maintaining hygiene. Between the part of the membrane 8 covering the concentration chamber 5 and the concentration chamber 5 there are provided air pockets 9 that are adapted to further reduce the noises being transmitted from the concentration chamber 5 to the environment.

The pressure pulse concentrator fig. 1 can be used by directly placing the membrane 8 on the skin of the patient or combining it with a conduction tube, as shown in fig. 3.

The use of a conical concentration chamber 5 is more based on the physical principles of fluid dynamics while previously known means for pressure pulse concentration and/or amplification utilize lenses or mirrors and are based on the acoustic principles of refraction and reflection.

Fig. 2 shows a conduction tube. The conduction tube comprises an orifice 1 1 connected to a concentration chamber 5. A planar pulse generator 2 is directly connected the concentration chamber 5.

At the opposite end of the cylindrical part 13, a reflection element 14 is provided with two surfaces 15 that are both arranged in a 45° angle relative to the direction of propagation 17 of the pressure pulse within the conduction tube. When the concentrated pressure pulse reaches the reflection element, it is split up into two parts and reflected in a direction that is perpendicular to its initial direction of propagation. The two parts of the initial pressure pulse, resulting from the split-up exit the conduction tube in opposite exit directions 17, 18 through a pair of opposite exit windows 19, 20. The exit windows are made of a pressure pulse permeable polymer. In alternative embodiments, a 360° circumferential exit window or one or several exit windows that are open only at certain divisions of the circumference may be formed.

The conduction tube, including the output window or windows and, if present, an outer coating, may be produced by injection molding as a single part.

In alternative embodiments, the conduction tube may not have a reflection element such that the pressure pulse keeps its initial direction of propagation and exits the conduction tube through an end face surface.

The outer surface of the conduction tube is covered by a polymeric coating 21 that reduces noise exiting from the conduction tube and may be suited for skin contact.

Alternative, similar embodiments can be combined with air pockets as shown in figure 1 . Fig. 3 shows an applicator comprising an pressure pulse concentrator which is adapted to concentrate a planar pressure pulse, and an conduction device, which is adapted to conduct the concentrated planar pressure pulse to a delivery location.

In particular, Fig. 3 shows a combination of the pressure pulse generator shown in fig. 1 and the conduction tube 10 as shown in fig. 2. The orifice 1 1 of the conduction tube 10 is connected to the outlet 8 of the pressure pulse concentrator. The separation into two fluid compartments may be advantageous with regard to patient safety requirements.

Such an embodiment can be advantageous when the conduction tube is designed as a single-use consumable so as to increase hygiene. A fresh, unused conduction tube can be attached to the pressure pulse concentrator and detached after use to be disposed of, while the pressure pulse concentrator can be intended for multiple uses.

To facilitate the use and assembly, the conduction tube may be pre-filled with a fluid or gel and closed by a Shockwave transmitting membrane at the interface for attaching the pressure pulse concentrator.

In alternative embodiments, the Shockwave conductor may be adapted to be filled with a gel or fluid manually by a user before the start of treatment.

In other embodiments, the pressure pulse concentrator 1 and conduction tube 10 may be provided without a dividing membrane or may be, for example, integrally formed as a single part.

In use, a planar pressure pulse is generated by the planar pulse generator 2 and travels in a linear direction through the concentration chamber 5. Where the pressure pulse contacts the walls of the inclined conical walls sections 22 of the concentration chamber 5, the pressure amplitude within the boundary areas of the pressure pulse close to the wall are accumulated due to the contact. While the pressure pulse traverses the concentration chamber 5, its cross-sectional area is decreased and its pressure amplitude is increased such that upon exiting the concentration chamber 5 through the outlet, substantially the complete cross section of the pressure pulse has an increased pressure amplitude in comparison to the initial pressure amplitude at the planar pulse generator. The effect is further supported by choosing the inner dimensions of the concentration chamber 5 similar to the spatial length of the pressure pulse.

The concentrated pressure is then entering the conduction tube, where it is linearly conducted until it reaches the reflection element. When impinging on the reflection element, the direction of propagation of the pressure pulse is altered and it exits the conduction tube through at least one output window to reach the desired application site.

Figure 4 schematically shows a concentration chamber 5 having the shape of a blunt cone that is rotation-symmetric about an axis 23. Planar pressure pulses enter the concentration chamber 5 through an inlet 6 and exit it after being concentrated through an outlet 7.

Within the concentration chamber 5 the pressure pulse propagates in a linear direction 3 and maintains a generally planar wave front while traversing the cone-shaped concentration chamber 5. The direction of propagation 3 is collinear with the axis of the cone-shaped concentration chamber 5. The extension of the pressure pulse's wave front at subsequent moments is indicated by lines 24, 25, 26, 27. These lines indicate that the wave front is generally perpendicular to the direction of propagation and at any moment parallel to a cross section of the cone-shaped concentration chamber 5.

On the left side of the axis 23, the increase of the pressure amplitude in different positions of the pulse's wave front is schematically shown by dashed lines. The same pressure profile will develop on the opposite side of the concentration chamber. As can be seen on the first wave front line 24, there occurs an increase of the pressure close to the wall 22, while the inner parts of the wave front distant from the wall remain at the initial pressure level. Thereby, a boundary area of increased pressure which is concentric to the central axis 23 develops close to the wall. As the pressure pulse travels through the narrowing concentration chamber, both the pressure amplitude and the geometrical thickness of the boundary area increases. At the outlet 7, most of the wave front has an increased pressure. In certain embodiments, the geometry of the concentration chamber can be chosen so that the boundary areas overlap at the outlet so that the complete wave front has an increased pressure at the outlet.

Further arrangements of the invention may be as follows.

1. A method for generating a concentrated planar pressure pulse, comprising the steps of creating a generally planar pressure pulse with a direction of propagation, increasing the pressure amplitude of the pressure pulse with an amplification means characterized in that the pressure pulse is transmitted towards a tapered wall section of the amplification means, which is inclined relative to the direction of propagation, wherein a boundary area of the pressure pulse collides with the tapered wall section and the pressure amplitude of the pressure pulse is accumulated in the boundary area.

2. The method of arrangement 1 , characterized in that the initial pulse width of the pressure pulse is more than 1 s and less than 100 s, in particular at least 5 s and less than 100 s. 3. The method of one of the preceding arrangements 1 or 2, characterized in that the cross section of the pressure pulse is reduced by 50 to 80 % between an inlet and an outlet of the amplification means.

4. The method of one of the preceding arrangements 1 to 3, characterized in that an inclination angle between the tapered wall section and the direction of propagation of the planar pressure pulse is more than 20 degrees and not more than 40 degrees.

5. The method of one of the preceding arrangements 1 to 4, characterized in that the inclination angle (a) between the tapered wall section and the direction of propagation of the planar pressure pulse is variable, wherein, in particular, the inclination angle increases following an essentially parabolic curve.

6. The method of one of the preceding arrangements 1 to 5, characterized in that the concentrated planar pressure pulse is conducted through an elongated conduction tube after exiting the amplification means.

7. The method of arrangement 6, characterized in that a direction of propagation of the concentrated planar pressure pulse is altered within the conduction tube.

8. The method of one of the preceding arrangements 1 to 7, characterized in that the concentrated planar pressure pulse is reflected within the conduction tube.

9. The method of one of the preceding arrangements 1 to 8, characterized in that the concentrated pressure pulse is split and conducted in at least two different directions within the conduction tube.