CZ308217B6 - Electrically conductive material needle for influencing living tissue - Google Patents

Abstract

A needle of electrically conductive material for influencing living tissue, where there is a body (3) in the end region for controlled electrical heating of a portion of the needle. The needle is a solid metal core with an inner conductor function (1) of steel, titanium, brass with a circular cross section and an outer diameter of 0.3 mm, the needle heater (3) is 1 to 10 mm long and the needle core is 10 to 15 cm long for undercutting the skin and parallel to the skin surface, and the outside the preselected length from the needle tip is covered by an electrically insulating layer (4), the outer conductor (2) of the needle is a highly electroconductive lacquer, ink or paste comprising a material selected from silver, copper, nickel, and the outer surface of the needle has a biocompatible protective layer (8) e.g. of gold, the heating element (3) is carbon based or a metal coating.

Description

Field of technology

The invention relates to a needle made of electrically conductive material for influencing living tissue.

Prior art

In medicine, often in aesthetic medicine, it is necessary to heat a small portion of the tissue, a few cubic millimeters, to a temperature of about 70 degrees Celsius to achieve the targeted effects described below. Currently available techniques can be used to perform local heating within the tissue mainly for aesthetic purposes in the following ways:

- highly focused ultrasound using ultrasonic generators with piezoelectric hemispherical transducers with an internal diameter of 2 to 4 cm. These hemispheres are located about 1 cm above the skin, with the epicenter where the ultrasound waves are focused at a depth of 1.5 to 4 mm. Here, energy of 1 to 10 J is generated, which causes the tissue to heat up to about 70 degrees Celsius - the heated tissue is about 1 to 5 cubic mm in volume. The disadvantage of this solution is that already on the surface of the skin, the ultrasonic waves are partially focused at the point of penetration and the skin bruises, which reduces the comfort of this procedure. Another disadvantage is the inaccuracy in the case of a specific point targeting requirement. The head with needles measuring 40x 20 mm does not allow precise aiming, eg when lifting the eyes. Another disadvantage is that ultrasonic generators have a relatively short lifespan and the treatment is expensive for the patient.

- radio frequency - using a system of insulated heads, a high-frequency electric current is supplied to the subcutaneous tissue, which heats the tissue to turn off and compact the skin. In this case, the subcutaneous tissue is only heated, it is not possible to achieve the local heating of 70 degrees Celsius, which is needed to denature the collagen. This method does not allow targeted heating.

- Intense pulsed light from a source of monochromatic light radiation is able to perform photothermolysis during depilation, when monochromatic light of a certain wavelength acts on dark follicles of hair, heats them and the hairs subsequently fall out. This method is capable of targeted heating only during depilation - generally not, in addition, eye protection is necessary.

- laser beams are able to purposefully destroy tissue, but the laser beam is very intense, it is not able to sensitively and accurately cause thermal heating only in the interval of 50 to 70 degrees Celsius. Eye protection is required.

In all the above cases, the tissue is heated so that ultrasonic waves, electric current, electromagnetic radiation (light) act on the tissue and heat it, which brings with it the above-mentioned drawbacks. It is an object of the present invention of the thermowell that the needle heats itself after being inserted into the tissue and then transfers the heat generated only to the surrounding tissue. In this way, it is possible to target very precisely where the tissue is to be targeted to a temperature of 50 to 70 degrees Celsius, and in addition, the temperature at the application site can be measured relatively accurately. This achieves greater accuracy while at the same time increasing comfort for the patient, the procedure does not bring side effects / pain / or discomfort / protection of the eyes from the harmful effects of electromagnetic waves /.

Part of the state of the art is the document WO 01/28488 A1, which describes a resistance-heated needle, in which heating is provided by a spiral of metal wire placed in the tip of the needle, from which it is electrically isolated by a layer of insulator. The present solution achieves the same effect, but using a different technology and design, which brings the following advantages. The heating resistor in the needle tip is formed by aspirating the resistive suspension into the space between the inner surface of the needle and the stripped segment of the central supply conductor and subsequently curing it. The main advantage is

- 1 GB 308217 B6 the fact that the diameter of the needle can be arbitrarily small. Another advantage is that more insulated segments can be formed on the central conductor, whereby any number of heating elements can be formed along the entire length of the needle. Finally, a significant advantage is the very low thermal inertia of the formed needle, as it is a compact structure where heat is transferred from the resistive material directly to the metal of the needle, without undesired thermal insulating parts. This is important for aesthetic medicine, where the transfer of thermal energy in short times is required.

Another prior art document is WO 2011/139086 A2, which relates to an electrically formed needle of not very small diameter, the individual parts of which are made of different materials. The needle is longitudinally divided, due to the supply of current to the heating element in the tip and does not allow the formation of a very thin needle.

Document US 2017/0348039 describes a heated needle with a diameter exceeding 1 mm, which is supplied with a high-frequency current, where the thermal effect occurs by a combination of induction heating of a metal tip and resistance heating by a spiral formed by a coated conductor. Since these are needles for aesthetic purposes, it is necessary to achieve the smallest possible needle diameter, with a limit diameter of 0.3 mm, which the described construction of the needle does not allow.

WO 2011/037235 describes resistance heated needles for surgical purposes, which additionally comprise a resistance temperature sensor. The shown construction of the needles eliminates the possibility of forming a needle up to 0.3 mm, as described in the present solution according to the present invention.

The essence of the invention

The invention relates to a needle made of electrically conductive material for influencing living tissue, in which a heating member or body is integrated in the region of its end or tip for controlled heating of a part of the needle when the needle is inserted into living tissue, and where this member or body is connected via an outer the needle wire and the inner needle wire are connected to a power source. The essence of the invention is that the needle is formed of a solid metal core with an inner conductor function of a material selected from the group consisting of steel, titanium, brass having a circular cross-section and an outer diameter of 0.3 mm, wherein the needle heating element has a length of 1 to 10 mm, and the needle core is 10 to 15 cm long for subcutaneous and parallel skin applications and is covered by an electrically insulating layer outside the preselected length from the needle tip, the outer needle guide being a layer of highly electrically conductive varnish, ink or paste. , comprising a material selected from the group consisting of silver, copper, nickel, and wherein the outer surface of the needle is provided with a biocompatible protective layer, e.g. of gold, the heating element being based on carbon or a metal coating.

The heating element of the needle preferably has a length of 5 mm and the needle core has a length of preferably 11 cm for injection applications under the skin and parallel to the surface of the skin.

The needle is preferably formed of a solid metal core with an inner conductor function, on which an electrically insulating layer is situated, which is at least in the region of the needle tip of a material doped with conductive impurities and thus forms an electrically conductive layer as a heating element, and where at least part of the remaining length of the needle, a layer of electrically conductive material doped with elements of an order of magnitude reducing its electrical conductivity is situated on the core, the outer surface of the needle being provided with a biocompatible protective layer.

In an alternative embodiment, the needle may be formed of a thin-walled metal tube extending into a closed tip, which forms an outer conductor, in which a metal inner conductor is located electrically insulated at the end of the needle opposite to the tip, the outer surface of the needle being biocompatible. protective layer.

-2 CZ 308217 B6

The needle can be designed as a hollow needle with the function of an inner guide for the possibility of aspirating dissolved fat or damaged tissue, or introducing a therapeutic solution into the tissue, where the outer diameter of the needle is 0.6 mm and the inner diameter 0.2 mm, with manufacturing tolerances where the needle has a length of 10 to 15 cm and is covered at least for part of its length with an electrically insulating layer, the outer conductor of the needle being formed by a layer of highly electrically conductive varnish, ink or paste containing a material selected from the group consisting of silver, copper, nickel and the heating element is based on carbon or a metal coating and has a length of 1 to 10 mm.

The electrically heated heating element is integrated at the end of a solid needle with a diameter usually in the region of 0.3 mm or a hollow needle with an outer diameter in the region of 0.5 to 3 mm. The electrically heated heating element, integrated at the end of a solid needle with a diameter of about 0.3 mm or a hollow needle with an outer diameter of about 0.5 to about 3 mm, has two connecting conductors, and therefore current passes only through these conductors and the heating element, and not by the patient's body. The heating element is heated only after the needle has been inserted into the skin, the heating can be realized either by a precisely defined power for a certain time, i.e. a precise dose of energy, or as a heating to a precise and measured temperature for a certain time, i.e. a precise thermal action. The advantages are that the unheated part of the needle is cold, does not damage the surrounding tissue, nor does it cause pain to the patient. When inserting the needle into the skin and pulling it out, the whole needle is cold, so even thanks to the thinness of the whole needle, no visible punctures remain on the skin. It is possible to measure and regulate the temperature of the needle directly and with a smaller time delay also the temperature of the surrounding tissue. The needle can be provided with a mechanical stop, which precisely defines the depth of the injection, and thus also the depth and tissue in which the heating element is located. It can be inserted into the skin other than vertically, allowing penetration into areas that are otherwise difficult to access.

The needle is very small in space and can be inserted basically wherever it is needed, it can also be very long, which, when inserted into the skin parallel to the surface, allows therapy to be performed on a single injection even over a long distance.

The service life of the needle can be, depending on the production process used, in the hundreds to thousands of needles, the costs of its acquisition are small.

Explanation of drawings

Exemplary embodiments of the present invention are shown in the accompanying drawings. In Fig. 1B, the needle is made of a solid metal core with the function of an inner conductor, pre-ground into a tip which, except for a selected length from the tip, is covered for most of its length with an insulating layer and a heating element on the core in the tip area. Fig. 1A is a detail of the needle tip of Fig. 1A.

Figures 2A and 2B show a modification of the embodiment according to Figure 1, in which the outer conductor is formed directly from a biocompatible material, e.g. conductive lacquer, platinum, etc. The heating element is significantly longer here, depending on the intended application it can be 1, 2, 3 long. mm or even 10 mm.

Fig. 3 is a further modification of the embodiment of the needle according to Fig. 1, where the heating element does not have to be formed only on the tip of the needle, but substantially anywhere along its length.

The needle in Figs. 4A and 4B is formed of a solid metal core with the function of an inner conductor, pre-ground into a tip, on which a layer of electrically insulating material is deposited, which is doped at the tip with conductive impurities so as to form an electrically conductive layer acting as heating element. A layer of electrically conductive material is applied to the core, which is doped with elements that significantly reduce its electrical conductivity. Their concentration is low at the tip and high for the rest of the length, which creates a layer with an order of magnitude greater electrical resistance than at the tip, and thus a negligible power dissipation in the passage of an electric current causing the needle to warm itself.

-3 CZ 308217 B6

In Figures 5A and 5B, the needle is formed of a thin-walled metal tube that forms an outer conductor. The inner conductor consists of an insulated wire, the end of which is stripped of the insulating layer to the required length. After threading the inner conductor into the outer tube so that its face is at the edge of the future needle edge, this assembly is dipped in an electrically conductive varnish which penetrates into the tube and the space between the two conductors. After the lacquer has hardened, the needle is ground to the desired shape without exposing the inner conductor. The base material is then applied to the needle under a biocompatible protective layer, which simultaneously strengthens the blade surface, and the final biocompatible protective layer.

Figures 6A and 6B show a modification of the embodiment of Figure 5, where the needle is formed of a pre-ground thin-walled metal tube which forms the outer conductor. The inner conductor consists of an insulated wire, the end of which is stripped of the insulating layer to the required length. A part of the inner conductor without insulation is soaked in the electrically conductive varnish before it hardens, the whole conductor is inserted into the tube so that its face is at the edge of the needle tip. The integrating base material is placed on the whole needle under the biocompatible protective layer, while the surface of the blade, resp. the tip is selectively closed and the blade eventually reground. Subsequently, the final biocompatible protective layer is rendered.

Figures 7A and 7B show another modification of the embodiment of Figure 6, wherein the needle cavity in the blade surface is closed by welding metal microspheres (laser) instead of selective galvanic delivery.

Fig. 8 is an assembly of needles that are mounted in a common holder.

In Figs. 9A and 9B, the needle is in the form of a hollow needle.

Examples of embodiments of the invention

For all illustrated embodiments, the needle has a circular cross-section (but if the application requires it, it may be different) and the outer diameter of the resulting needle is about 0.3 mm (smaller and possible needles for shorter needles and usually larger for longer needles) .

In the embodiment according to Figs. 1A and 1B, the needle is formed of a solid metal core with the function of an inner conductor 1 (steel, titanium, brass, etc.) pre-ground into the shape of a needle. This core is covered for most of its length with an insulating layer 4 (thermoplastic or thermoset), except for the selected length from the tip. At the tip of the needle and through it, a heating element 3 is formed on the core, for example of carbon lacquer or a metal coating with low conductivity, formed by a chemical or galvanic process, steaming, sintering or another form of coating. The whole needle is covered with a layer of highly conductive varnish, eg containing silver, copper, nickel, etc., which creates an outer conductor 2. After the surface of the insulating layer 4 (commonly used methods - eg colloidal carbon, palladium process, etc.) is an outer conductor 2, usually made of copper, is galvanically formed on the entire surface of the needle. After restoring the blade of the formed needle, the whole needle is coated with a biocompatible protective layer 5, e.g. of gold.

Figures 2A and 2B show an embodiment of the needle, where the outer conductor 2 is formed directly from a biocompatible material (biocompatible outer conductor 6 made of special conductive varnishes, platinum, etc.) and further covering layers are thus no longer needed. In addition, the heating element 3 shown here is significantly longer - depending on the intended application, it can be 1, 2, 3 mm or even 10 mm long.

Fig. 3 shows a modification of the needle, in which the heating element 3 does not have to be formed only on the tip of the needle, but substantially anywhere on its length.

In Figs. 4A and 4B, the needle is formed of a solid metal core with the function of an inner conductor 1 (steel, titanium, brass, etc.) pre-ground into the shape of a needle.

-4 CZ 308217 B6

a) A layer 4 of electrically insulating material is applied to the core by chemical or galvanic process, steaming, sintering or other form of coating, which is doped at the tip with conductive additives so as to form an electrically conductive layer which then acts as a heating element 3.

b) A layer of electrically conductive material (metal), which is doped with elements significantly reducing its electrical conductivity, is deposited on the core by chemical or galvanic process, evaporation, sintering or other form of coating. Their concentration is low at the tip and high for the rest of the length, which creates a layer with an order of magnitude greater electrical resistance than at the tip, and thus a negligible power dissipation in the passage of an electric current causing the needle to warm itself.

The subsequent layers forming the outer conductor 2 and possibly also the biocompatible protective layer 4 are identical to the embodiment according to FIG.

In Figures 5A and 5B, the needle is formed of a thin-walled metal tube (steel, titanium), which forms the outer conductor 2. The inner conductor 1 consists of an insulated wire (copper wire in enamel, polyurethane, polyester or other insulation), the end of which is in the desired length stripped of insulating layer. After threading the inner conductor 1 into the outer tube so that its face is on the edge of the future needle edge, this assembly is dipped in electrically conductive varnish, which (possibly with the help of vacuum) penetrates into the tube and the space between the two conductors 1, 2. the needle is ground to the desired shape, the inner conductor 1 must not be exposed. The base material (substrate 7) is now galvanically deposited on the whole needle under a biocompatible protective layer (copper), which simultaneously strengthens the blade surface, and the final biocompatible protective layer 8.

The needle in Figs. 6A and 6B is formed of a needle-shaped thin-walled metal tube (steel, titanium) which forms the outer conductor 2. The inner conductor 1 consists of an insulated wire (copper wire in enamel, polyurethane, polyester or other insulation). the end of which is stripped of the insulating layer to the required length. The insulated part of the inner conductor 1 is soaked in an electrically conductive varnish (e.g. carbon) and before it has hardened, the whole conductor is inserted into the tube so that its face is at the edge of the needle edge. The integrating base material (substrate 7) is now galvanically deposited on the entire needle under the biocompatible protective layer 8 (copper), the surface of the blade being selectively closed and the blade possibly reground again. Subsequently, the final biocompatible protective layer 8 is galvanically rendered.

Figures 7A and 7B show a modification of the embodiment of Figure 6, wherein the cavity in the blade surface is closed by welding metal microspheres (laser), instead of by selective galvanic discharge. The blade edge will be very hard.

Fig. 8 shows an embodiment of an assembly of two needles, in which it is advantageous to insert more needles simultaneously in order to influence a larger area of tissue due to time savings. Such a set of needles can be made either separately and then fastened to a common holder, but advantageously their production can also be used together with their carrier and the discharged outer layers can thus be used directly as an electrical connection.

Figures 9A and 9B show a hollow needle which makes it possible to aspirate dissolved fat or damaged tissue or, conversely, to inject a therapeutic solution into the tissue on the right. In this case, the outer diameter of the needle is, for example, 0.6 mm and the inner diameter is 0.2 mm. The production process is similar to the case of Fig. 1 to Fig. 8, only instead of a full inner conductor 1 a tube (steel, titanium, brass, etc.) is used, which is temporarily blinded with a removable plug before production or is continuously cleaned or blown during production. . If all biocompatible materials are used (biocompatible inner conductor 5, biocompatible outer conductor 6), grinding of the resulting needle blade can be performed only as a last operation.

It is always a matter of producing a thin needle of the required length, depending on the penetration depth requirement (5 mm to eg 110 mm for oblique subcutaneous application), with a certain length (eg 1 to 5 mm

-5 CZ 308217 B6 selected according to the field of application) is heated by means of an electric current passing through a resistance heating element 3 formed in the internal structure of this needle.

To achieve sufficient strength and durability of the needle even if a very small overall diameter is required (approx. 0.3 mm, while for short needles there may be smaller diameters, on the contrary for longer needles or hollow needles with larger diameter) the whole system is formed coaxially as follows :

- the outer shell of the entire surface of the needle is made of electrically conductive material and thus forms one pole for the heating element 3

- the second pole for the heating element 3 is formed by an inner conductor 1 insulated along its entire length from the outer sheath

the heating element 3 itself is made of a material with a lower conductivity than the supply conductors, located in a selected length at the end of the needle between the inner and outer conductors J, 2.

For a needle with an outer diameter of 0.3 mm, for example, the inner conductor 1 can be 100 .mu.m in diameter, the resistive layer at the tip or the insulation for the rest of the length 2x 50 .mu.m, the outer conductor 2 2x 2x .mu.m thick, the protective biocompatible layer 5 gold 2x 1 pm.

Construction options:

a) - an insulator (enamel, polyurethane, etc., coated conductor (copper)) is passed through a tube (stainless steel) with the required outer diameter;

- at the end of the inner conductor 1 it is removed in the required length of insulation;

- the unit is immersed in an electrically conductive varnish / ink / paint / paste (different manufacturers call it differently) on the basis of eg carbon due to high resistance, i.e. low conductivity compared to the supply conductors;

- the inner conductor 1 is pulled back into the tube so that its face is hidden to a defined depth from its end;

- the electrically conductive varnish / ink / paint / paste is allowed to dry / cure by a process defined by the manufacturer; this creates a conductive connection of the inner and outer conductor with a measurable non-zero resistance;

- the end of the tube is ground to the desired shape;

- if all biocompatible materials have been used, they can be ground until the inner conductor 1 appears on the ground surface (the tension between the exposed inner and outer conductor 1, 2 on the forehead will be so low that there is no risk of injury to the patient);

- if the inner materials (conductor or resist layer) are not biocompatible, they are ground so that the inner conductor 1 is not exposed, and then they are applied (chemically or galvanically) to the whole needle of the biocompatible protective layer 5 (copper and gold, etc.).

b) - similar to a), only starting with a tube already pre-sharpened into the shape of the resulting needle (eg a finished insulin needle can be used);

- after the resistance layer has hardened, it is only necessary to gently restore the blade of the original needle, and if not all materials are biocompatible, additional outer protective layers are applied.

-6 CZ 308217 B6

c) - the solid wire (steel, titanium, brass, etc.) which will form the inner conductor 1 is ground approximately into the shape of the resulting needle and this end is coated with a less conductive and the rest of the length with an insulating coating;

- optionally, a pre-insulated wire is used, at the end of which the insulating layer is removed to the required length;

- after curing of the coatings, some of the known methods of conducting the surface of the insulator (palladium, colloidal carbon, etc.) are used;

- a galvanically conductive (copper, iron, etc.) layer of the required thickness (10 to 50 μm) is applied to the entire surface thus conducted, which will form the outer conductor 2;

- the exact required shape of the needle is sharpened so that the galvanically carried outer conductor 2 on the front of the needle is not completely ground (the advantage is that more material is galvanically carried on the tips, ie the layer will be thicker here)

- a biocompatible coating (gold) is applied to the entire needle.

d) - if a less conductive coating is formed on the inner conductor 1 by chemical means (e.g. oxidation, nitriding, evaporation, coating / refining of carbide, etc.), an insulating layer can be formed in the same way, only a modified composition is used so that the resulting conductivity layer 4 on the rest of the length of the needle was many times higher than the conductive at the tip;

- this procedure will heat the whole needle, not only its tip, but in the insulating part, for example, only by a hundredth of a power, ie its final warming will be negligible and will not affect the overall function;

- the advantage of this solution is the fact that the whole surface will be conductive already in this step, i.e. it is possible to omit the process of conducting the surface of the insulator, in which chemicals that are strongly incompatible are mostly used; in addition, the adhesion of the subsequently deposited galvanic layer (copper, iron) to the metal substrate along the entire length of the needle will also be significantly higher, and thus the susceptibility to damage will be reduced.

e) - if ad c) the conductive coating is formed by an electrically conductive varnish, or ink, paint or paste, which can be applied to insulators and which can then be directly galvanized, it can be applied along its entire length (even through the insulating layer 4) and again omit the problematic process of conducting the insulator surface.

Needles with more heated areas along their length can be created by similar procedures.

The needles thus obtained can be soldered or fed behind a carrier part (tube or central wire) to a carrier (printed circuit board or other suitable conductive material) and the second pole connected to the electronics, ensuring the supply of the needle with the required voltage and current.

If copper and gold are to be galvanically removed on the outer surface of the needle, the needles can be mechanically fastened to the carrier before this step, thus directly protecting and galvanically connecting more needles to the carrier.

Most of the materials used in the manufacture of this needle have a non-zero coefficient of dependence on temperature and it will therefore be possible to measure the temperature of these materials, and thus the temperature of the heating element 3 itself, and thus the temperature of the surrounding tissue with calibrated accuracy. In addition, when more metallic materials (iron, copper, nickel, etc.) come into contact, a thermoelectric voltage is created, which will again be measurable, and from it also the temperature of this transition can be determined. The application possibilities of these needles can be extended to the use of a significantly longer needle (10 to 15 cm in length), which is inserted separately under the skin and at the same time

-7 CZ 308217 B6 with the skin surface will move back and forth in its desired direction along its length. The skin is stretched during the treatment, when the end of the needle heats up and when moving back and forth it creates a coagulation in the path of movement, which has a similar effect as lifting the mesonite. It causes scarring with contraction in the direction of the scarring and in the subcutaneous tissue it results in tightening of the skin. This method can be repeated in a fan-shaped manner, for example from a point in front of the ear in a fan-shaped range from the support wing to the angle of the jaw.

Claims (3)

PATENT CLAIMS A needle made of electrically conductive material for influencing living tissue, wherein a heating member or body (3) is integrated in the region of its end or tip for controlled heating of a part of the needle when the needle is inserted into living tissue, and wherein said member or body is connected thereto. the outer conductor (2) of the needle and the inner conductor (1) of the needle, which are separated by an electrically insulating layer (4), connected to a source of electric current, characterized in that the needle is formed of a solid metal core with the function of an inner conductor (1) of a material selected from the group consisting of steel, titanium, brass having a circular cross-section and an outer diameter of 0.3 mm, where the heating element (3) of the needle has a length of 1 to 10 mm, and the needle core has for undercutting and parallel to the surface leather 10 to 15 cm long, the outer conductor (2) of the needle being formed by a layer of highly electrically conductive varnish, ink or paste containing o a material selected from the group consisting of silver, copper, nickel, and wherein the outer surface of the needle is provided with a biocompatible protective layer (8), e.g. of gold, the heating element (3) being based on carbon or a metal coating. The needle according to claim 1, characterized in that the heating element (3) of the needle has a length of preferably 5 mm and the needle core has a length of preferably 11 cm for injection applications under the skin and parallel to the surface of the skin. The needle according to claim 1, characterized in that it is formed of a solid metal core with the function of an inner conductor (1), on which an electrically insulating layer (4) is situated, which is at least in the region of the needle tip of a material doped with conductive impurities and thus forming an electrically conductive layer in the function of the heating element (3), and wherein at least part of the remaining length of the needle a layer of electrically conductive material doped with elements reducing its electrical conductivity is situated on the core, the outer surface of the needle being provided with a biocompatible protective layer (8).