LOW- AND MID-FREQUENCY ULTRASOUND DEVICE WITH ENHANCED CAVITATION EFFECT IN COMBINATION WITH RADIAL IN-DEPTH SKIN THERAPY

Field of the invention

The invention relates to a device for the treatment of subcutaneous fat tissue, specifically to a device that uses low- and mid-frequency ultrasound waves in combination with in-depth skin therapy.

Technical problem

The technical problem solved by this device is the design and construction of a device that includes an applicator for destruction of subcutaneous fat tissue using low- and mid-frequency ultrasound in combination with in-depth vacuum therapy. Additionally the device described in the invention, must be able to filter any excess gel absorbed into the device's interior during therapy. Cavitation is the process by which subcutaneous fat cells are selectively and non-surgically removed by applying concentrated ultrasound energy to a certain tissue depth. The skin surface, veins, nerves and muscles are not affected by the treatment. Fat from the destroyed fat cells is deposited into the extracellular fluid in the form of triglycerides. Under the influence of enzymes, it is broken up into glycerol and free fatty acids. The water-soluble glycerol enters the bloodstream and is used for energy while the insoluble fatty acids travel to the liver and are digested just like any other free fatty acid (including acids from food). The cavitation effect of ultrasound is only strong enough for therapeutic use in the frequency range between 20 kHz and 500 kHz. Since the applicator must be pressed against the skin during therapy, this increases possibility of transferring ultrasound energy into deeper levels of body, which is undesired and potentially harmful. Determining suitable subcutaneous treatment depth with an applicator without applying pressure represents a significant technical problem. In vacuum technology, there exist applicators which create a skin fold inside the interior of the applicator. If the same applicator contained an ultrasound source for the destruction of subcutaneous fat cells, it would be possible to perform both types of therapy simultaneously. This would not only create a sum of the effects of both therapies resulting in a shorter time period, but would also have important synergy effects. The principal design problem is the optimal ratio between the size of the ultrasound source and the size of the bell-shaped housing that creates the conditions required for a vacuum.

During therapy, the combination of negative pressure and ultrasound gel presents a problem. The gel is often used for easier entry of ultrasound into tissue, but the gel could also be absorbed into the vacuum part of the applicator, which is inconvenient.

Prior state of the art

Ultrasound cavitation therapy is usually combined with endodermic vacuum massages. Until now, these therapies have been conducted one after another. There are currently several devices on the market that offer either deep therapy/massages or cavitation using ultrasound.

EP1260208 describes a device for circular deep vacuum therapy where a skin fold is formed in the applicator.

Devices that use high-frequency ultrasound between 1 and 30 MHz for diagnostic purposes are well-known. Several devices are also known that use ultrasound waves with frequencies between 1 and 5 MHz for thermal treatment of subcutaneous tissue. Devices also exist that use low-frequency ultrasound waves to break kidney stones. There are also known examples of devices that use low-frequency ultrasound to induce cavitation and destroy subcutaneous fat cells.

Devices that utilize the cavitation effect are manufactured by companies such as Ultrashepe ZDA, Liposonix and Bothell, all from the USA. The device from patent application WO2008114186A2 is also known. The company Enraf Nonius srl (Netherland) produces a device that combines ultrasound with vacuum fixation. The weakness of the device in question is that the vacuum-inducing dish is made of rubber. During use, the rubber dish deforms and adheres to the skin. The device is based on ultrasound between 1 and 3 MHz and is stationary. The vacuum is used to fix the ultrasound electrodes to the tissue.

WO2008114186A2 describes cavitation therapy, but does not combine it with vacuum therapy.

EP1386597A1 and EP1219278A2 describe the use of ultrasound therapy in combination with vacuum therapy. From the shape and size of the ultrasound source, it is evident that the source is exclusively high-frequency. Low-frequency ultrasound sources have different design requirements. The disadvantage of these devices is that high frequency ultrasound does not achieve the same cavitation effect as low frequency ultrasound. The described system does not include a round bell shaped housing that would allow formation of a skin fold inside the cup and would be the most important part of radial deep therapy.

WO 2006/091093 describes a combination of high frequency ultrasound that does not include the low and medium frequency cavitation effect, and a deformable vacuum cup for fixation. It utilizes only the gel pads and cannot allow use of cheaper and commonly used ultrasound gel that is not solid, since it does not provide a solution for removal of excess liquefied gel via a filtration system in the handle.

A device manufactured by Emme srl (Italy) uses high-frequency ultrasound between 1 and 3 MHz in combination with deformable fixation vacuum cup. Due to the high ultrasound frequency, the cavitation effect is not strong enough for therapeutic use. Description of the solution to the technical problem

The low- and mid-frequency ultrasound device for cavitation in combination with radial deep skin therapy according to the invention has an ultrasound head built into a solid bell-shaped housing with the bottom side curved outward and a suitably smooth surface for easier movement across the skin. A unique design feature of the device according to the invention is that the ultrasound head is built into the bell-shaped housing in such a way that the therapeutic part of the ultrasound head reaches up to approximately one third of the height of the bell-shaped housing that enables vacuum therapy. Additionally, excess gel is removed via a filtration system in the handle.

The device according to the invention will be described in further detail using figures that show:

Figure 1 - the device assembly

Figure 2 - the device with a ring-shaped skin fold

Figure 3 - ultrasound head 5

The device according to the invention has a roughly oval-shaped handle 1 that widens slightly in its lower part 1a, followed by a narrower ring-shaped part 1b with engraved threads. At the top of handle 1 is a round opening 1d for the cables of the ultrasound head and opening 1e for the tube of the vacuum pump. In the upper part of handle 1 , there is a round hole 1c for a plug that can be used to admit air (decompress interior) for easier removal of the device at the end of the therapy. A bell-shaped housing 2 is fastened to the narrow part 1b using the inner thread of the fastening ring 3. Inside it is the cone-shaped housing of the ultrasound head 5 which is fixed to handle 1 using thread 4a. The space between parts 1 and 4 serves as a filter - reservoir for any absorbed impurities, especially ultrasound gel. The housing 4 is divided into three segments using rings 4c and 4e, which prevents gel from entering the interior of the device using the capillary effect. Housing 4 consists of a cylindrical part 4a with engraved threads, a cylindrical part 4b with a ring-shaped part 4c, which continues into part 4d (shaped like a truncated cone). Between parts 4d and 4f, there is a ring-shaped part 4e. Part 4f is shaped like a truncated cone and ends at cylindrical part 4g with threads where the lid 6 is screwed after attaching the ultrasound head 5.

A unique design feature of the device according to the invention is that the ultrasound head 5 is built into the solid bell-shaped housing 2 in such a way that the therapeutic part of the head 5a reaches up to approximately one third of the height of the bell- shaped housing 2.

The device also comprises an attached or integrated electrical signal generator for ultrasound control and a vacuum pump for the purposes of vacuum therapy.

The device according to the invention combines ultrasound cavitation therapy with an endodermic vacuum massage, allowing the skin fold to be closer to ultrasound head 5 without putting pressure on any internal organs in the vicinity of the treated skin. Ultrasound head 5 can be made using the principle of a low-frequency ultrasound source in the 10-500 kHz range. There are several possible implementations of the ultrasound source, the most common being the piezoelectric crystal. It is possible to use a piezoelectric source where the piezoelectric crystal is surrounded by metal plates on the top and bottom. These plates act as a resonator.

Building the reservoir into the applicator itself solves the problem of ultrasound gel absorption. By using the capillary effect, the reservoir acts as a filtration system. Additionally, it is possible to use mechanical filters in the applicator, on the vacuum tube leading to the applicator, or inside the negative pressure pump. These filters prevent the ultrasound gel from being absorbed deeper into the vacuum system. Alternatively, conductive gel lining can be used. In this case, the gel is stored in a protective casing and thus not absorbed into the system. The device according to variant I has tubes for the application of therapeutic ultrasound gel built into the handle 1. The gel is applied using a pump which can be controlled either manually or by a computer. An automatic sensor system can be integrated into the system for easier gel application. Medical or cosmetic substances can be added to the gel.

The device according to the invention can be made with a convex or concave shape of the lower part of the ultrasound source, the upper part of the ultrasound source or the piezoelectric crystal itself. Thus, the ultrasound wave can be focused or defocused.

The device according to variant Il consists of several ultrasound sources spread over the surface of the ultrasound head. These ultrasound sources can be time- or phase- shifted. The sources can operate at the same frequency or at several different frequencies. One or more sources can operate in pulsed, continuous or modulated modes.

The device according to variant III includes one or more radiofrequency wave sources in handle 1. These allow skin heating or radiofrequency ablation.

The device according to variant IV includes an electronic circuit for estimation of skin depth and composition using a diagnostic ultrasound source. The system manually or automatically determines the optimal depth at which the system should operate and adjusts the parameters of the device accordingly.

The device according to variant V has the bell-shaped housing 2 shaped in such a way that the bottom side is oval.

The device according to variant Vl has an extended holder on the handle, allowing better grip. The device according to variant VII combines the ultrasound source in the bell- shaped housing 2 with one or more built-in balls, rollers, heating or cooling devices, electrical signal sources and/or sources of coherent or non-coherent light. The efficiency of a light source can be increased using materials that reflect light.

The device according to the invention can be used for intradermal or transdermal substance delivery, a phenomenon known as sonoporation. The advantages of the invention allow optimal effects in all points beneath the bell-shaped housing 2 and simultaneously ensure that moving the device over the patient's skin does not cause pain or discomfort.